This is a Division of application Ser. No. 12/457,779 filed Jun. 22, 2009. The disclosure of the prior application is hereby incorporated by reference herein in its entirety.
BACKGROUND1. Technical Field
The present invention relates to a substrate processing method and a substrate processing apparatus.
2. Description of Related Art
As one of the manufacturing steps of a semiconductor device such as IC, a substrate processing step using an ALD (Atomic Layer Deposition) method and a CVD (Chemical Vapor Deposition) method is performed. A vertical substrate processing apparatus is used as a substrate processing apparatus for performing the substrate processing step. The vertical substrate processing apparatus includes a reaction tube for forming a processing chamber; a gas supply unit for supplying processing gas into the processing chamber; an exhaust unit for exhausting inside of the processing chamber; and a heater unit for heating the inside of the processing chamber. The vertical substrate processing apparatus is capable of processing a plurality of substrates by a single batch processing, and therefore has a characteristic that throughput (productivity) is higher than a sheet-type substrate processing apparatus.
FIG. 20 is a schematic view showing a structure of a processing furnace of a conventional vertical substrate processing apparatus. This processing furnace includes areaction tube203′ made of, for example, quartz (SiO2). Aprocessing chamber201′ is formed in thereaction tube203′. Boats (not shown) as substrate holding tools for supporting a plurality of wafers as substrates, are loaded into theprocessing chamber201′ in multiple stages. The processing furnace includes a gas supply unit for supplying processing gas such as source gas and oxide gas into theprocessing chamber201′. The gas supply unit includes a firstgas supply tube232a′ for supplying the source gas (such as a gas containing element Zr); a secondgas supply tube232b′ for supplying the oxide gas (such as an ozone (O3) gas); a firstgas supply nozzle233a′ connected to the firstgas supply tube232a′; and a secondgas supply nozzle233b′ connected to the secondgas supply tube232b′. The firstgas supply nozzle233a′ and the secondgas supply nozzle233b′ are respectively provided in thereaction tube203′, so as to be vertically extended from a lower part of thereaction tube203′ to a ceiling part of thereaction tube203′ along an inner wall of thereaction tube203′. A plurality of gas jet holes are respectively provided in the firstgas supply nozzle233a′ and the secondgas supply nozzle233b′. An arrangement pitch of the gas jet holes is made to be same as a support pitch of the plurality of wafers (not shown) supported by the aforementioned boats (not shown) in multiple stages. The gas jet holes are constituted so that the processing gas can be flown along an upper surface of each wafer. The firstgas supply tube232a′ is connected to a source gas supply source for supplying source gas, through avalve243a′. The secondgas supply tube232b′ is connected to an oxide gas supply source for supplying oxide gas through a valve AV2′. Note that although not shown, the processing furnace further includes a carrier gas line for supplying N2gas, being a carrier gas (purge gas), into theprocessing chamber201′, and an exhaust unit for exhausting an atmosphere in theprocessing chamber201′.
For example, in the substrate processing step using the ALD method, first source gas supplying step→N2purging step→first exhausting step→second source supplying step→N2purging step→second exhausting step are set as one cycle, and this cycle is repeated multiple number of times. In the first source gas supplying step, the valve AV2′ is closed and thevalve243a′ is opened, while exhausting the inside of theprocessing chamber201′ by the exhaust unit (not shown), and the source gas is supplied into theprocessing chamber201′. Thus, the source gas jetted from each gas jet hole of the firstgas supply nozzle233a′ is flown horizontally on each wafer, then is adsorbed on the surface of the wafer, to thereby form a base film on the wafer. In the N2purging step, the valve AV2′ and thevalve243a′ are closed while continuing exhaust of the inside of theprocessing chamber201′ by the exhaust unit (not shown), and N2gas, being purge gas, is supplied into theprocessing chamber201′ from a carrier gas line (not shown). Thus, the source gas remained in theprocessing chamber201′ is discharged from theprocessing chamber201′, and the inside of theprocessing chamber201′ is purged. In the first exhausting step, supply of the N2gas from the carrier gas line (not shown) is stopped, with the valve AV2′ and thevalve243a′ closed, while continuing the exhaust of the inside of theprocessing chamber201′ by the exhaust unit (not shown). Thus, the inside of theprocessing chamber201′ is exhausted and cleaned. In the oxide gas supplying step, O3gas, being the oxide gas, is supplied into theprocessing chamber201′, with thevalve243a′ closed and the valve AV2′ opened, while continuing the exhaust of the inside of theprocessing chamber201′. Thus, the oxide gas jetted from each gas jet hole of the secondgas supply nozzle233b′ is flown horizontally on each wafer, which is then reacted with the base film formed on the wafer, to thereby form an oxide film on the wafer.
Thus, in the ALD method and the CVD method, oxide gas containing, for example, ozone, being oxide species, is used as a second source, so that ozone is horizontally supplied along an upper surface of each wafer. However, if processing is performed by a conventional vertical substrate processing apparatus, there is a tendency that oxidation is easily advanced on an outer peripheral side of the wafer to which ozone is supplied easily, and oxidation is delayed on a center side of the wafer to which ozone is hardly supplied. Therefore, a film thickness distribution and composition distribution in a surface of the wafer are deteriorated, thus generating variation in the characteristic of the semiconductor device, and a manufacturing yield of the semiconductor device is deteriorated in some cases.
Therefore, the following two methods have been examined. One of them is a method of preventing a delay in oxidation in the center part of the wafer, by increasing a flow speed of the oxide gas containing ozone on the wafer. The other one is a method of processing substrates uniformly in the surface, by eliminating an uneven oxidation over the whole wafer, by supplying to the wafer, a large flow rate of the oxide gas containing high density ozone.
However, in the former method, sufficient improvement is not observed, and it is difficult to sufficiently prevent the delay in oxidation in the center part of the wafer, and it is difficult to improve the manufacturing yield of the semiconductor device.
Further, in the latter method, the yield can be improved. However, a flow rate of high density ozone that can be supplied at once is reduced, in terms of a performance of ozonizer (not shown) of the oxide gas supply source, then supply time of ozone is prolonged, and throughput (productivity) is deteriorated.
An object of the present invention is to shorten a processing time and improve uniformity of a film thickness in the surface, when the oxide film is formed by supplying the oxide gas onto the substrate.
SUMMARY OF THE INVENTIONAccording to a first aspect of the present invention, there is provided a substrate processing method, including the steps of:
supplying source gas into a processing chamber in which substrates are accommodated;
removing the source gas and an intermediate body of the source gas remained in the processing chamber;
supplying ozone into the processing chamber, in a state of substantially stopping an atmosphere in the processing chamber;
removing the ozone and the intermediate body of the ozone remained in the processing chamber,
with these steps repeated multiple number of times, and the source gas and the ozone alternately supplied so as not to be mixed with each other, to thereby form an oxide film on the surface of the substrates.
According to other aspect of the present invention, there is provided a substrate processing method, including the steps of:
supplying source gas into a processing chamber in which substrates are accommodated;
exhausting an atmosphere in the processing chamber;
reserving the ozone into a gas reservoir connected to the processing chamber;
supplying into the processing chamber the ozone reserved into the gas reservoir; and
exhausting the atmosphere in the processing chamber,
with these steps repeated multiple number of times, and the source gas and the ozone alternately supplied so as not to be mixed with each other, to thereby form an oxide film on the surface of the substrates.
According to further another aspect of the present invention, there is provided a substrate processing method, including the steps of:
loading substrates into a processing chamber;
supplying ozone into the processing chamber, in a state of substantially stopping exhaust of an atmosphere in the processing chamber; and
removing the ozone and an intermediate body of the ozone remained in the processing chamber,
with the step of supplying ozone and the step of removing the ozone repeated multiple number of times, to thereby form an oxide film on the surface of the substrates.
According to further another aspect of the present invention, there is provided a substrate processing method, including the steps of:
reserving ozone into a gas reservoir connected to a processing chamber in which substrates are accommodated;
supplying into the processing chamber the ozone reserved into the gas reservoir; and
exhausting an atmosphere in the processing chamber,
with these steps repeated multiple number of times, to thereby form an oxide film on the surface of the substrates.
According to further another aspect of the present invention, there is provided a substrate processing apparatus, including:
a processing chamber that processes substrates;
a gas supply unit that supplies ozone into the processing chamber;
an exhaust unit that exhausts an atmosphere in the processing chamber; and
a controller,
with the gas supply unit including an ozone supply path connected to the processing chamber, and an ozone supply valve that performs open/close of the ozone supply path,
the exhaust unit including an exhaust path connected to the processing chamber, and an exhaust valve for opening and closing the exhaust path,
the controller controlling the gas supply unit and the exhaust unit, so that the ozone is supplied into the processing chamber from the ozone supply path, in a state of substantially stopping an exhaust of inside of the processing chamber, when the ozone is supplied into the processing chamber.
According to the present invention, when the oxide film is formed by supplying the oxide gas onto the substrates, it is possible to shorten a processing time and improve uniformity of the film thickness in the surface.
BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a schematic block diagram showing an entire structure of a substrate processing apparatus according to a first embodiment of the present invention.
FIG. 2 is a vertical sectional view of a processing furnace of the substrate processing apparatus according to the first embodiment of the present invention.
FIG. 3 is a horizontal sectional view corresponding to a sectional face taken along the line A-A of the processing furnace shown inFIG. 2.
FIG. 4 is a schematic block diagram of the processing furnace and a gas supply unit of the substrate processing apparatus according to a third embodiment of the present invention.
FIG. 5 is a sequence view of the step of forming an oxide film according to a comparative example.
FIG. 6 is a schematic view showing a sequence example 1 of the step of forming the oxide film (step3) according to a third embodiment of the present invention.
FIG. 7 is a schematic view showing a sequence example 2 of the step of forming the oxide film (step3) according to the third embodiment of the present invention.
FIG. 8 is a schematic view showing a sequence example 3 of the step of forming the oxide film (step3) according to the third embodiment of the present invention.
FIG. 9 is a table chart explaining examples 1 to 3 of the present invention together with a comparative example 1, showing an average oxide film thickness, a substrate center film thickness, and uniformity of film thickness.
FIG. 10 is a graph chart explaining examples 4 to 6 of the present invention together with a comparative example 2,FIG. 10A shows a relation between an increase of an average film thickness and oxidation time of the oxide film in a substrate surface, andFIG. 10B shows a relation between the increase of the film thickness and the oxidation time of the oxide film in a center part of the substrate, respectively.
FIG. 11 is a table chart for explaining examples 7 and 8 of the present invention together with comparative example 3, showing the average thickness and uniformity of the thickness of the oxide film in each case of an upper part and a lower part of a substrate processing position.
FIG. 12 is a table chart showing a composition uniformity of a HfO2film in each part of an upper part, a middle part, and a lower part of the substrate processing position, whereinFIG. 12A shows the composition uniformity of comparative example 4 and
FIG. 12B shows the composition uniformity of example 9, andFIG. 12C shows the composition uniformity of example 10, respectively.
FIG. 13 is a schematic block diagram of a processing furnace and a gas supply unit of the substrate processing apparatus according to a fourth embodiment of the present invention.
FIG. 14 is a view exemplifying an operation of the gas supply unit and a valve open/close sequence according to the fourth embodiment of the present invention.
FIG. 15 is a view exemplifying a cooling structure of a buffer tank according to the third embodiment of the present invention.
FIG. 16 is a view exemplifying other cooling structure of the buffer tank according to the third embodiment of the present invention.
FIG. 17 is a schematic block diagram when the gas supply unit according to the third embodiment is applied to a side flow-type vertical substrate processing apparatus.
FIG. 18 is a vertical sectional view of a processing furnace of the side flow type vertical substrate processing apparatus according to a second embodiment of the present invention.
FIG. 19 is a perspective view showing a modified example of an inner tube of the substrate processing apparatus according to the second embodiment of the present invention.
FIG. 20 is a schematic block diagram of a conventional vertical substrate processing apparatus.
DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTIONFirst EmbodimentFirst, a basic structure of a normal flow type vertical substrate processing apparatus according to a first embodiment of the present invention, and a substrate processing method executed by this substrate processing apparatus will be described.
(1) Structure of a Substrate Processing ApparatusFIG. 1 is a schematic block diagram showing an entire structure of a substrate processing apparatus according to this embodiment. As shown in the figure, asubstrate processing apparatus101 includes acasing111. In order to carry a wafer (substrate)200 made of silicon, etc, into/out of thecasing111, acassette110, being a wafer carrier accommodating the wafer (substrate)200 made of silicon, etc, is used. A front side maintenance port (not shown) is opened, as an opening part opened in a lower part of afront side wall111aof thecasing111 of thesubstrate processing apparatus101, so that maintenance of an inside of thecasing111 can be performed. A front side maintenance door (not shown) for opening/closing this front side maintenance port is built on thefront side wall111aof thecasing111. A cassette loading/unloading port (substrate container loading/unloading port)112 is opened on the maintenance door, so as to communicate inside and outside of thecasing111. The cassette loading/unloadingport112 is opened and closed by a front shutter (open/close mechanism of the substrate container loading/unloading port)113. A cassette stage (substrate container transferring stand)114 is installed inside of thecasing111 of the cassette loading/unloadingport112. Thecassette110 is loaded on thecassette stage114, and unloaded from thecassette stage114, by an in-step carrying device (not shown).
Thecassette110 is placed on thecassette stage114, so that thewafer200 in thecassette110 takes a vertical posture, and a wafer charging/discharging port of thecassette110 is faced upward. Thecassette114 is constituted, so that thecassette110 is vertically rotated by 90 degrees toward a rear of thecasing111, with thewafer200 set in a horizontal posture in thecassette110, and the wafer charging/discharging port of thecassette110 is faced rearward in thecasing111.
A cassette shelf (substrate container placement shelf)105 is set in approximately a longitudinally center part in thecasing111. Thecassette shelf105 is constituted, so that a plurality ofcassettes110 are stored in multiple stages and in multiple rows. Atransfer shelf123 is provided on thecassette shelf105, on which thecassette110, being a carrying object of awafer transfer mechanism125 as will be described later, is stored. Further, aspare cassette shelf107 is provided in an upper part of thecassette stage114, for storing thecassette110 as spare.
A cassette carrying device (substrate container carrying device)118 is installed between thecassette stage114 and thecassette shelf105. Thecassette carrying device118 includes a cassette elevator (substrate container elevation mechanism)118acapable of elevating thecassette110 in a state of holding thecassette110, and a cassette carrying mechanism (substrate container carrying mechanism)118b, being a carrying mechanism capable of horizontally moving thecassette110 in a state of holding thecassette110. By continuous motion of thesecassette elevator118aandcassette carrying mechanism118b, thecassette110 is carried among thecassette stage114, thecassette shelf105, and thespare cassette shelf107.
The wafer transfer mechanism (substrate transfer mechanism)125 is set in the rear of thecassette shelf105. Thewafer transfer mechanism125 includes a wafer transfer device (substrate transfer device) capable of horizontally rotating or linearly moving thewafer200, and a wafer transfer device elevator (substrate transfer device elevation mechanism)125bfor elevating thewafer transfer device125a. Note that thewafer transfer device125aincludes a tweezer (jig for transferring substrates)125cfor holding thewafer200 in a horizontal posture. The wafertransfer device elevator125bis installed on a right side end portion of thecasing111 having pressure resistance. By the continuous motion of thesewafer transfer device125aand wafertransfer device elevator125b, thewafer200 is picked up from the inside of thecassette110 on thetransfer shelf123 and charged into a boat (substrate supporting member)217 as will be described later and discharged form theboat217, and stored in thecassette110 on thetransfer shelf123.
Aprocessing furnace202 is provided in a rear upper part of thecasing111. An opening (furnace port) is formed in a lower end portion of theprocessing furnace202. This opening is opened/closed by a furnace port shutter (furnace port open/close mechanism)147. Note that a structure of theprocessing furnace202 will be described later.
A boat elevator (substrate holding tool elevation mechanism)115, being an elevation mechanism for elevating theboat217 and carrying it to inside/outside of theprocessing furnace202, is provided in a lower part of theprocessing furnace202. Anarm128, being a connecting tool, is formed on an elevating stand of theboat elevator115. Aseal cap219 is provided on thearm128, as a lid member, for vertically supporting theboat217 and air-tightly sealing the lower end portion of theprocessing furnace202 when theboat217 is elevated by theboat elevator115.
Theboat217 includes a plurality of holding members, so that a plurality of (for example, about 50 to 150)wafers200 are horizontally held respectively, in a state of being arranged in a vertical direction, with centers thereof aligned.
Aclean unit134aincluding a supply fan and a dust-proof filter is provided above thecassette shelf105. Theclean unit134ais constituted so that clean air, being cleaned atmosphere, is flown into thecasing111.
Further, aclean unit134bincluding the supply fan and the dust-proof filter for supplying clean air is installed on a left side end portion of thecasing111, on the opposite side to the side of the wafertransfer device elevator125band theboat elevator115. The clan air blown out from theclean unit134bis circulated around thewafer transfer device125aand theboat217, then sucked in an exhaust device not shown, and exhausted to the outside of thecasing111.
(2) Operation of the Substrate Processing ApparatusNext, an operation of thesubstrate processing apparatus101 according to this embodiment will be described.
Prior to supplying thecassette110 to thecassette stage114, the cassette loading/unloadingport112 is opened by thefront shutter113. Thereafter, thecassette110 is loaded from the cassette loading/unloadingport112. Thecassette110 is placed on thecassette stage114, so that thewafer200 is set in a vertical posture and the wafer charging/discharging port of thecassette110 is faced upward. Then, thecassette110 is vertically rotated by 90 degrees toward the rear of thecasing111 by thecassette stage114. As a result, thewafer200 in thecassette110 is set in a horizontal posture, and the wafer charging/discharging port of thecassette110 is faced rearward in thecasing111.
Next, thecassette110 is automatically carried and transferred to thecassette shelf105 and a shelf position designated by thespare cassette shelf107, then stored temporarily therein, and transferred to thetransfer shelf123 from thecassette shelf105 or thespare cassette shelf107, or directly carried to thetransfer shelf123.
When thecassette110 is transferred to thetransfer shelf123, thewafer200 is picked up from thecassette110 through the wafer charging/discharging port by thetweezer125cof thewafer transfer device125a, and charged into theboat217 in the rear of the transfer chamber124 by the continuous motion of thewafer transfer device125aand the wafertransfer device elevator125b. After thewafer200 is transferred to theboat217, thewafer transfer device125areturns to thecassette110 so that thenext wafer200 is charged into theboat217.
When previously designated sheets ofwafers200 are charged into theboat217, the lower end portion of theprocessing furnace202, which is closed by thefurnace port shutter147, is opened by thefurnace port shutter147. Subsequently, by elevating theseal cap219 by theboat elevator115, theboat217 holding a group ofwafers200 is loaded into theprocessing furnace202.
After loading, arbitrary processing is applied to thewafer200 in theprocessing furnace202. This processing will be described later. In a reversed procedure to the aforementioned procedure, thewafer200 and thecassette110 are discharged to outside of thecasing111.
(3) Structure of the Processing FurnaceNext, the structure of theprocessing furnace202 according to this embodiment will be described.
FIG. 2 is a vertical sectional view of theprocessing furnace202 of the substrate processing apparatus according to this embodiment, andFIG. 3 is a horizontal sectional view corresponding to the line A-A of theprocessing furnace202 shown inFIG. 2.
(Processing Chamber)Theprocessing furnace202 according to an embodiment of the present invention includes thereaction tube203 and amanifold209. Thereaction tube203 is made of a non-metal material having heat resistance property, such as quartz (SiO2) and silicon carbide (SiC), and is formed into a cylindrical shape, with an upper end portion closed and a lower end portion opened. The manifold209 is made of a metal material such as SUS, and is formed into a cylindrical shape, with the upper end portion and the lower end portion opened. Thereaction tube203 is vertically supported by the manifold209 from the side of the lower end portion. Thereaction tube203 and the manifold209 are concentrically disposed. The lower end portion of the manifold209 is air-tightly sealed by theseal cap219 when theaforementioned boat elevator115 is elevated. An O-ring220, being a sealing member, for air-tightly sealing the inside of theprocessing chamber201 is provided between the lower end portion of the manifold209 and theseal cap219.
Theprocessing chamber201 accommodating thewafer200, being the substrate, is formed inside of thereaction tube203. Theboat217, being a substrate holding tool, is inserted into theprocessing chamber201 from below. Inner diameters of thereaction tube203 and the manifold209 are made larger than a maximum outer diameter of theboat217 into which thewafer200 is charged.
Theboat217 is constituted so that a plurality of (for example 75 to 100)wafers200 are held in multiple stages, with prescribed gaps (substrate pitch intervals) provided in approximately horizontal states. Theboat217 is mounted on aheat insulating cap218 for insulating thermal conduction from theboat217. Theheat insulating cap218 is supported from below by a rotational shaft255. The rotational shaft255 is provided so as to pass through the center part of theseal cap219, while an air-tight state of the inside of theprocessing chamber201 is maintained. Arotating mechanism267 for rotating the rotational shaft255 is provided below theseal cap219. By rotating the rotational shaft255 by therotating mechanism267, theboat217, on which a plurality ofwafers200 are mounted, can be rotated, while the air-tight state of the inside of theprocessing chamber201 is maintained.
Aheater207, being a heating unit (heating mechanism) is provided on an outer periphery of thereaction tube203, concentrically with thereaction tube203. Theheater207 has a cylindrical shape, and is vertically installed on a heater base207aby being supported thereby as a holding plate shown inFIG. 3. Thewafer200 and the atmosphere in the processing chamber are heated by a radiation heat from theheater207.
(Gas Supply Unit)A firstgas supply nozzle233ais provided in themanifold209. The firstgas supply nozzle233ais formed into an L-shape having a vertical portion and a horizontal portion. The vertical portion of the firstgas supply nozzle233ais formed linearly along a loading direction of thewafers200, and is extended from the lower part of theprocessing chamber201 to the vicinity of a ceiling part of theprocessing chamber201, through a circular arc shaped space in a planar view, between the inner wall of thereaction tube203 and thewafer200 on theboat217. A plurality of first gas jet holes248a, being gas inlet ports for introducing gas into theprocessing chamber201, are vertically provided on the side face of the vertical portion (cylinder portion) of the firstgas supply nozzle233a. The first gas jet holes248aare provided at the same pitch as the pitch of loading thewafer200 held by theboat217, so that the gas is horizontally flown along the upper surface of eachwafer200 on theboat217. Further, the first gas jet holes248ahave mutually the same opening areas, to thereby equalize the flow rate of the gas flowing on eachwafer200. Note that an opening diameter of each of the first gas jet holes248amay be set to be gradually larger from the lower part to the upper part.
The horizontal portion of the firstgas supply nozzle233ais provided so as to pass through the side wall of themanifold209. The firstgas supply tube232afor supplying source gas (TEHAH gas and TEMAZ gas) obtained by vaporizing a liquid source such as tetrakisdimethyl amino hafnium (Hf[NCH3C2H5]4; TEHAH) and tetrakisdimethyl amino zirconium (TEMAZ) containing element Hf(hafnium) and element Zr(zirconium), is connected to an upper stream end of the firstgas supply nozzle233a. A liquid source supply source, amass flow controller240, being a flow rate control device (flow rate controller), avaporizer242 for generating the source gas by vaporizing the liquid source, and afirst valve243a, are provided in the firstgas supply tube232a, sequentially from an upper stream.
A first carriergas supply tube234afor supplying N2GAS, being a carrier gas (purge gas), is connected to a lower stream side of thefirst valve243aof the firstgas supply tube232a. A carrier gas supply source not shown, a secondmass flow controller241b, being a flow rate control device (flow rate controller), and athird valve243care provided in the first carriergas supply tube234a, sequentially from the upper stream.
A secondgas supply nozzle233bis provided in themanifold209. The secondgas supply nozzle233bis formed into an L-shape having the vertical portion and the horizontal portion. The vertical portion of the secondgas supply nozzle233bis formed linearly along the loading direction of thewafers200, and is extended from the lower part of theprocessing chamber201 to the vicinity of the ceiling part of theprocessing chamber201, through a circular arc shaped space in a planar view, between the inner wall of thereaction tube203 and thewafer200 on theboat217. A plurality of second gas jet holes248b, being the gas inlet ports for introducing the gas into theprocessing chamber201, are vertically provided on the side face of the vertical portion (cylinder portion) of each secondgas supply nozzle233b. The second gas jet holes248bare provided at the same pitch as the pitch of loading thewafer200 held by theboat217, and are respectively formed so that the gas is horizontally flown along the upper surface of eachwafer200 on theboat217. Further, the second gas jet holes248bhave mutually the same opening areas, to thereby equalize the flow rate of the gas flowing on eachwafer200. Note that the opening diameter of each of the second gas jet holes248bmay be set to be gradually larger from the lower part to the upper part.
The horizontal portion of the secondgas supply nozzle233bis provided so as to pass through the side wall of themanifold209. The secondgas supply tube232bfor supplying ozone (O3) gas, being the oxide gas, is connected to the upper stream end of the secondgas supply nozzle233b. An ozone gas supply source, a firstmass flow controller241a, being the flow rate control device (flow rate controller), and an ozone supply valve AV2 are provided in the secondgas supply tube232bsequentially from the upper stream.
Avent gas tube232vis connected between themass flow controller241aof the secondgas supply tube232b, and the ozone supply valve AV2. A sixth valve243vis provided in the vent gas tube232v. When the ozone gas is not supplied into theprocessing chamber201, the sixth valve243vis opened and ozone is discharged from thevent gas tube232v, without stopping the generation of ozone, to thereby stably and rapidly start next supply of ozone into theprocessing chamber201.
A second carriergas supply tube234bfor supplying N2gas, being a carrier gas (purge gas), is connected to the lower stream side of the ozone supply valve AV2 of the secondgas supply tube232b. A carrier gas supply source not shown, a thirdmass flow controller241c, being the flow rate control device (flow rate controller), and afourth valve243dare provided in the second carrier gas supply tube243b, sequentially from the upper stream.
A source gas supply unit according to this embodiment is mainly constituted by the firstgas supply nozzle233a, the firstgas jet hole248a, the firstgas supply tube232a, a liquid source supply source not shown, the liquidmass flow controller240, thevaporizer242, thefirst valve243a, the first carriergas supply tube234a, and the secondmass flow controller241b, and thethird valve243c. Also, an oxide gas supply unit according to this embodiment is mainly constituted by the secondgas supply nozzle233b, the secondgas getting port248b, the secondgas supply tube232b, an ozone gas supply source not shown, the firstmass flow controller241a, the ozone supply valve AV2, thevent gas tube232v, the sixth valve243v, the second carriergas supply tube234b, a carrier gas supply source not shown, the thirdmass flow controller241c, and thefourth valve243d. In addition, a gas supply unit for supplying the source gas and the oxide gas into theprocessing chamber201 is mainly constituted by the source gas supply unit and the oxide gas supply unit.
Thus, the gas supply unit for supplying gas of two kinds (the source gas and the oxide gas) into theprocessing chamber201, is provided in thesubstrate processing apparatus101. Then, a desired film is formed on thewafer200, by alternate supply of the gas of two kinds into theprocessing chamber201. Further, in the film forming step, the inside of theprocessing chamber201 is cleaned by being exhausted using avacuum pump246, after being purged using the carrier gas. Further, desired processing can be performed by replacing a part of the gas supply unit with a device suitable for processing.
(Exhaust Unit)Anexhaust tube231 is connected to the side wall of themanifold209. Afifth valve243e, being an exhaust valve, and thevacuum pump246 are provided in theexhaust tube231 sequentially from the upper stream side. Note that thefifth valve243ecan control start/stop of vacuum exhaust of theprocessing chamber201 by opening/closing the valve, and further is constituted as an automatic pressure adjustment valve (APC valve) capable of adjusting a pressure in theprocessing chamber201 by adjusting an opening degree of the valve. An exhaust unit for exhausting the atmosphere in theprocessing chamber201 is mainly constituted by theexhaust tube231, thefifth valve243e, and thevacuum pump246.
(Controller)The substrate processing apparatus according to this embodiment includes acontroller280, being a control part (control means). Thecontroller280 is connected to the liquidmass flow controller240, first to thirdmass flow controllers241a,241b,241c, first tosixth valves243a,243b,243c,243d,243e,243v, theheater207, thevacuum pump246, therotating mechanism267, and a boat elevating mechanism not shown. Thecontroller280 is constituted to control flow adjustment operation of the liquidmass flow controller240 and the first to thirdmass flow controllers241a,241b,241c, open/close operation of the first to fourth andsixth valves243a,243b,243c,243d,243c, open/close operation and opening degree adjustment operation of thefifth valve243e, temperature adjustment operation of theheater207, start/stop of thevacuum pump246, rotating speed adjustment of therotating mechanism267, and elevating operation of the boat elevating mechanism.
(4) Substrate Processing StepNext, explanation will be given for the substrate processing step according to this embodiment executed as one of the manufacturing steps of the semiconductor device. The substrate processing step according to this embodiment is executed by the aforementioned substrate processing apparatus (normal flow type vertical substrate processing apparatus). In the explanation given hereunder, the operation of each part constituting the substrate processing apparatus is controlled by thecontroller280.
In the substrate processing step according to this embodiment, TEMAH gas is used as the source gas, and ozone gas is used as the oxide gas, to thereby form an HfO2film on thewafer200 by using the ALD method. The ALD method, being one of the CVD methods is a method of forming a film by supplying on the substrate the reactive gas of two kinds, being at least sources of two kinds used in film-formation, alternately one by one, which is then adsorbed on the substrate in units of one atom, and film-formation is performed by utilizing a surface reaction. At this time, control of the film thickness is performed by less number of cycles (for example, if a film forming speed is 1 Å/cycle, the reactive gas is supplied by 20 cycles when a film of 20 Å is formed). In the film-formation processing using the ALD method, a processing temperature for depositing HfO and ZrO is set to be 180° C. to 270° C., and for example set to be 250° C. In the ALD method, for example, when the HfO2film is formed, high quality film-formation is possible at a low temperature such as 180 to 250° C. by using the TEMAH gas and the ozone gas.
(Wafer Loading Step)First, as described above, thewafer200 is charged into theboat217, and is loaded into theprocessing chamber201. After theboat217 is loaded into theprocessing chamber201, four steps as will be described later are sequentially executed.
(Source Gas Supplying Step (Step1))Instep1, the TEMAH gas, being the source gas, is supplied into theprocessing chamber201, while exhausting the atmosphere in theprocessing chamber201 in which thewafer200 is accommodated.
Specifically, thefifth valve243eof theexhaust tube231 is opened, and exhaust of the atmosphere in theprocessing chamber201 is started. Then, thethird valve243cof the first carriergas supply tube234ais opened, and the N2gas, being the carrier gas, is flown to the firstgas supply tube232a, while adjusting the flow rate by the secondmass flow controller241b. Further, TEMAH being the liquid source, is flown to thevaporizer242 from the liquid source supply source not shown to be vaporized, while adjusting the flow rate by the liquidmass flow controller240, to thereby generate the TEMAH gas. Then, thefirst valve243aof the firstgas supply tube232ais opened, and the TEMAH gas generated by thevaporizer242 is flown to the firstgas supply nozzle233a. The TEMAH gas is mixed with the carrier gas in the firstgas supply tube232a. Mixed gas of the TEMAH gas and the carrier gas is supplied into theprocessing chamber201, through the firstgas jet hole248aof the firstgas supply nozzle233a. Surface reaction (chemical adsorption) is caused between TEMAH in the mixed gas supplied into theprocessing chamber201, and a surface part of thewafer200, to thereby form a base film on thewafer200. An excess portion of the mixed gas not contributing to forming the base film, is exhausted from theexhaust tube231 as exhaust gas.
At this time, the opening degree of thefifth valve243eis set, so that the pressure in theprocessing chamber201 is set so as to be maintained in a range of 0.1 to 400 Pa, and for example set to be 200 Pa. Further, the flow rate of TEMAH controlled by the liquidmass flow controller240 is set to be 0.01 to 0.1 g/min, and the time for exposing thewafer200 to the mixed gas is set to be 30 to 180 seconds. Moreover, the temperature of theheater207 is adjusted, so that the temperature of thewafer200 is set to be in a range of 180 to 250° C. and for example set to be 230° C.
(Source Gas Removing Step (Step2))Instep2, the TEMAH gas and the intermediate body of the TEMAH gas remained in theprocessing chamber201 are removed.
Specifically, thefirst valve243aof the firstgas supply tube232ais closed, and supply of the TEMAH gas into theprocessing chamber201 is stopped. At this time, the inside of theprocessing chamber201 is exhausted by thevacuum pump246 down to 20 Pa or less, with thefifth valve243eof theexhaust tube231 opened, and the residual TEMAH gas and intermediate body of the TEMAH gas are removed from theprocessing chamber201. Note that thethird valve243cof the first carriergas supply tube234ais opened until removal of the residual TEMAH gas and intermediate body of the TEMAH gas from the processing chamber is completed, and N2, being purge gas, is supplied into theprocessing chamber201 while adjusting its flow rate by using the secondmass flow controller241b. Thus, an effect of removing the residual TEMAH gas and intermediate body of the TEMAH gas from theprocessing chamber201 is further improved.
(Ozone Supplying Step (Step3))Instep3, ozone is supplied into theprocessing chamber201, with the exhaust of the atmosphere in theprocessing chamber201 substantially stopped.
Specifically, by closing thefifth valve243eof theexhaust tube231, the exhaust of inside of theprocessing chamber201 is substantially stopped. Then, thefourth valve243dof the second carriergas supply tube234bis opened, and the N2gas, being the carrier gas, is flown to the secondgas supply tube232b, while adjusting its flow rate by using the thirdmass flow controller241c. Further, the ozone supply valve AV2 of the secondgas supply tube232bis opened, and the ozone gas, being the oxide gas, is flown to the secondgas supply nozzle233b, while adjusting its flow rate by using the firstmass flow controller241a. The ozone gas is mixed with the carrier gas in the secondgas supply tube232b. The mixed gas of the ozone gas and the carrier gas are supplied into theprocessing chamber201 through the secondgas jet hole248bof the secondgas supply nozzle233b. Ozone in the mixed gas supplied into theprocessing chamber201 causes surface reaction with TEMAH which is chemically adsorbed on the surface of thewafer200, to thereby form the HfO2film on thewafer200. An excess portion of the mixed gas not contributing to forming the HfO2film is exhausted from theexhaust tube231 as exhaust gas.
At this time, the opening degree of thefifth valve243eis set, so that the pressure in theprocessing chamber201 is maintained in a range of 0.1 to 400 Pa and for example maintained to be 200 Pa. Further, the time for exposing thewafer200 to O3is set to be 10 to 120 seconds. Moreover, the temperature of theheater207 is adjusted, so that the temperature of thewafer200 is set to be in a range of 180 to 250° C. in the same way as the time for supplying the TEMAH gas ofstep1, and for example, set to be 230° C.
(Repeating Step)Thereafter, theaforementioned steps1 to4 are set as one cycle, and by repeating this cycle multiple number of times, the HfO2film of desired thickness is formed on thewafer200, and the substrate processing step according to this embodiment is ended. Then, thewafer200 after processing is unloaded from theprocessing chamber201, by a procedure reverse to the wafer loading step.
(5) Advantage of this Embodiment
According to this embodiment, one or a plurality of advantages are exhibited, as shown below.
(a) According to this embodiment, the ozone supplying step (step3) for supplying ozone into theprocessing chamber201 is performed, with exhaust of the atmosphere in theprocessing chamber201 substantially stopped.
Thus, ozone is diffused and the inside of theprocessing chamber201 is reserved with ozone, so that ozone can be sufficiently supplied not only to the outer peripheral edge, but also to the center part of thewafer200. As a result, the processing time for forming the HfO2film can be shortened, and homogeneity of distribution of thickness and distribution of composition of the HfO2film formed on thewafer200 can be improved.
(b) Further, according to this embodiment, the TEMAH gas and ozone are alternately supplied into theprocessing chamber201 so as not to be mixed with each other. Thus, excess vapor phase reaction in theprocessing chamber201 can be suppressed, film forming reaction can be efficiently generated on thewafer200, and the processing time for forming the HfO2film can be shortened. Moreover, generation of particles in theprocessing chamber201 can be suppressed, and homogeneity of the distribution of thickness and distribution of composition of the HfO2film formed on thewafer200 can be improved.
(c) Moreover, according to this embodiment, the aforementioned advantage can be obtained, by performing the ozone supplying step (step3), with exhaust of the atmosphere in theprocessing chamber201 substantially stopped, and there is no necessity for supplying ozone of large flow rate into theprocessing chamber201. Therefore, waste of ozone can be suppressed, and cost required for processing substrates can be reduced.
Second EmbodimentNext, a basic structure of the side flow type vertical substrate processing apparatus and a substrate processing method using this substrate processing apparatus, according to a second embodiment of the present invention will be described.
As shown inFIG. 18, the substrate processing apparatus according this embodiment is different from the substrate processing apparatus according to the aforementioned embodiment, in the point that thereaction tube203 is constituted of anouter tube31 and aninner tube38 disposed inside of theouter tube31. In addition, the substrate processing apparatus according to this embodiment is different from the substrate processing apparatus according to the aforementioned embodiment in the point that a plurality ofexhaust ports41 are provided on the side wall of theinner tube38 so that exhaust passed through the plurality ofexhaust ports41 is discharged from anexhaust port35 provided in a lower part of theouter tube31. Other structure is the same as that of the normal flow type vertical substrate processing apparatus.
The side flow type vertical substrate processing apparatus will be described below, focusing on these different points.
FIG. 18 is a vertical sectional view of a side flow type processing furnace according to this embodiment. As shown in the figure, the reaction tube according to this embodiment is constituted of theouter tube31, and theinner tube38 disposed inside of theouter tube31. Theouter tube31 and theinner tube38 are respectively made of non-metal materials having heat resistance property, such as quartz (SIO2) and silicon carbide (SiC) and have a cylindrical shape, with the upper end portion closed and the lower end portion opened. Theouter tube31 is vertically supported by the manifold209 from the side of the lower end portion. Areceiver base31aprojecting toward inside is formed on an inner wall surface of the lower part of theouter tube31. A plurality ofprojection parts38aprojecting toward outside are formed on an outer wall surface of the lower part of theinner tube38. Theinner tube38 is vertically supported from below in theouter tube31, by setting theprojection parts38aon thereceiver base31a.Cylindrical space39 extending vertically is formed between the outer wall surface of theinner tube38 and the inner wall surface of theouter tube31. Theprocessing chamber201 is formed inside of theinner tube38, so that theboat217 is inserted from below.
The vertical portion of the firstgas supply nozzle233aand the vertical portion of the secondgas supply nozzle233bare respectively extended to the vicinity of the ceiling part of theprocessing chamber201, through a circular arc-shaped space in planar view, between the inner wall of theinner tube38 and thewafer200 on theboat217.
A plurality ofexhaust ports41 are provided at positions opposed to the firstgas supply nozzle233aand the secondgas supply nozzle233b. The plurality ofexhaust ports41 are provided at the same pitch as the pitch of loading thewafer200 held by the boat217 (namely, an arrangement pitch of the first gas jet holes248aand the second gas jet holes248b), so that the gas is horizontally flown along the upper surface of eachwafer200 on theboat217. Note that theexhaust port35, with theexhaust tube231 connected thereto, is formed on the lower part of the side wall of the manifold209 (below the lower end of the inner tube38).
In addition, afurnace port34, being an opening, is formed on the lower end of themanifold209. Thefurnace port34 is constituted so as to be sealed by aseal cap219, being a disc (lid member) having an outer diameter larger than an inner diameter of thefurnace port34, through an O-ring (seal ring)220. In addition, arotational shaft64 of therotating mechanism267 is provided so as to pass through an axial center part of theseal cap219. A support stand is vertically erected on the upper end of therotational shaft64. Theboat217, being a substrate holding tool, is vertically erected on the support stand.
When the boat holding a plurality ofwafers200 is inserted into theprocessing chamber200 and theprocessing chamber201 is sealed by theseal cap219, the inside of theprocessing chamber201 is exhausted down to a prescribed pressure or less, by thevacuum pump246 connected to theexhaust tube231, and the temperature inside of theprocessing chamber201 is raised to a prescribed temperature. Then, theboat217 is rotated by a rotational shaft62 of a rotation driving mechanism63. With a structure of a hot wall type furnace structure, the temperature in theprocessing chamber201 is maintained uniformly over the whole, and temperature distribution of theboat217 and eachwafer200 held thereby is also uniform over the whole.
According to this embodiment, one or a plurality of effects shown below are further exhibited, in addition to the aforementioned effects.
(a) According to this embodiment, the firstgas supply nozzle233a, the secondgas supply nozzle233bare provided inside of theinner tube38, so as to be extended in a loading direction of the plurality ofwafers200. Further, a plurality ofexhaust ports41 are provided at positions of theinner tube38 opposed to the firstgas supply nozzle233aand the secondgas supply nozzle233b. Thus, a horizontal flow of the source gas and the oxide gas can be formed over eachwafer200. Then, uniformity in the surface of the HfO2film, etc, formed on eachwafer200 can be improved.
(b) In addition, according to this embodiment, the firstgas supply nozzle233aand the secondgas supply nozzle233bare disposed so as to be close to the outer edge of thewafer200 held by theboat217. Thus, supply efficiency of the source gas and the oxide gas to thewafer200 can be improved, and productivity of processing substrates can be improved. In addition, supply amount of the gas to the vicinity of the center of thewafer200 can be increased, and the uniformity in the surface of the thickness of the HfO2film formed on thewafer200 can be improved.
(c) In addition, according to this embodiment, vertically continuedspace39 is formed between the outer wall surface of theinner tube38 and the inner wall surface of theouter tube31. Further, theexhaust port35 is provided on the lower side of the opening end of theinner tube38. Thus, both of the gas passed through thespace39 between theinner tube38 and theouter tube31, and the gas from the opening end of the inner tube can be simultaneously exhausted, and replacement efficiency of the gas can be improved.
FIG. 19 is a perspective view showing a modified example of theinner tube38 shown inFIG. 18.
A different point from the substrate processing apparatus explained inFIG. 18 is a point thatexhaust port41A is opened on a ceiling wall of theinner tube38. Theexhaust port41A is provided on the opposite side (the side of a plurality of exhaust ports41) to the side where theexhaust tube231 is provided. According to this modified example, the horizontal flow of the gas jetted from the firstgas jet hole248aof the firstgas supply nozzle233a, and the gas jetted from the secondgas jet hole248bof the secondgas supply nozzle233bcan be respectively suppressed, and gas purge efficiency in theprocessing chamber201 can be improved. Note that it is desirable to set the size of theexhaust port41A to be optimum, by comparing a horizontal flow suppressing effect and the gas purge efficiency.
Third EmbodimentNext, explanation will be given for the structure of the substrate processing apparatus according to the third embodiment of the present invention, and the substrate processing step executed by this substrate processing apparatus.
(1) Structure of the Substrate Processing ApparatusFirst, the structure of the substrate processing apparatus according to this embodiment will be described, with reference toFIG. 4.FIG. 4 is a schematic block diagram of the processing furnace and the gas supply unit of the substrate processing apparatus according to this embodiment. This embodiment is different from the aforementioned embodiment in the point that the ozone gas, being the oxide gas, is supplied into theprocessing chamber201 pulsatively by the gas supply unit (flush supply). Note that the structure other than the gas supply unit is the same as that of the first embodiment, excluding an oxidation sequence of thecontroller280. The structure of the gas supply unit of the substrate processing apparatus according to this embodiment will be described hereinafter.
As shown inFIG. 4, a lower stream end of the firstgas supply tube232ais connected to the upper stream end of the firstgas supply nozzle233a. The upper stream end of the firstgas supply tube232ais connected to the secondary side (outlet) of a vaporizingchamber242aformed in thevaporizer242. The lower stream end of atransfer tube100 is connected to the primary side (inlet) of the vaporizingchamber242a. The upper stream end of thetransfer tube100 is inserted (immersed) into the TEMAH, being a liquid source stored in atank305 as a liquid source supply source. A valve AV4 and the liquidmass flow controller240 are provided in thetransfer tube100 sequentially from the upper stream side. The lower stream end of a compressedgas supply tube51 is connected to an upper space of the TEMAH stored in thetank305, so that the N2gas, being the compressed gas, is supplied from the compressedgas supply tube51. A valve AV3 is provided in the compressedgas supply tube51. The lower stream end of the first carriergas supply tube234ais connected to the inside of the vaporizingchamber242a, so that the N2gas, being the carrier gas (purge gas) is supplied thereto. A carrier gas supply source not shown, the secondmass flow controller241b, and thethird valve243care provided sequentially from the upper stream side, in the first carriergas supply tube234a. A switchingvalve50 is provided in thevaporizer242. By this switchingvalve50, switching is possible to either one of a switching position (called a carrier gas supply position hereinafter) for communicating the inside of thetank305 and the vaporizingchamber242a, and a switching position (called a carrier gas supply position) for communicating the first carriergas supply tube234aand the firstgas supply tube232athrough the vaporizingchamber242a.
The lower stream end of the secondgas supply tube232bis connected to the upper stream end of the secondgas supply nozzle233b. Anozonizer52, being an ozone generating apparatus, an ozone inlet valve AV1, the firstmass flow controller241a, abuffer tank102, being a gas reservoir connected to theprocessing chamber201, and an ozone supply valve AV2 are provided in the secondgas supply tube232b. Theozonizer52 is an apparatus for generating ozone gas from oxygen (O2) by discharge. Oxygen gas is supplied to theozonizer52 from an oxygen gas supply line not shown. Thebuffer tank102, being the gas reservoir, is constituted as a pressure vessel temporarily charged with ozone gas supplied into theprocessing chamber201 pulsatively. Namely, after the inside of thebuffer tank102 is temporarily charged with ozone gas supplied from theozonizer52, this ozone gas is supplied (flush-supplied) into theprocessing chamber201 pulsatively. Note that in this embodiment, the second carriergas supply tube234bis removed, unlike the substrate processing apparatus according to the first embodiment.
Regarding the source gas generated by vaporization of the liquid source in thevaporizer242, re-liquefaction is apt to occur depending on its type. Therefore, a supply route of the source gas (the upper stream side of the firstgas supply tube232aand the firstgas supply nozzle233a) to theprocessing chamber201 from the secondary side of the vaporizer242 (outlet) is heated to a prescribed temperature (for example, 130° C. when TEMAZ is used as the liquid source), to thereby suppress the re-liquefaction of the source gas. Specifically, a ribbon heater (not shown), etc, is provided on an outer surface of the aforementioned supply route of the source gas (the upper stream side of the firstgas supply tube232aand the firstgas supply nozzle233a).
In addition, in order to accelerate vaporization of the liquid source in thevaporizer242, the supply route (transfer tube100) of the liquid source from thetank305 to thevaporizer242 is heated to a prescribed temperature, to thereby preheat the liquid source supplied to thevaporizer242. Specifically, the ribbon heater (not shown), etc, is provided on the outer surface of the supply route (transfer tube100) of the liquid source.
Note that when the ribbon heater (not shown) is provided on the outer surface of the supply route (the upper stream side of thetransfer tube100, the firstgas supply tube232a, and the firstgas supply nozzle233a) of the liquid source and the source gas, to thereby heat the inside of the supply route, the inside of thebuffer tank102 is also heated by heat conduction, thus decomposing ozone reserved into thebuffer tank102. Therefore, the inside of thebuffer tank102 is cooled. For example, as shown inFIG. 15, a coolingcoil300 is provided on the outer surface of thebuffer tank102, and by flowing a heat exchanging medium such as chilling water and industrial water into the coolingcoil300, thebuffer tank102 is cooled. In addition, as shown inFIG. 16, it is also acceptable that thebuffet tank102 is provided inside of athermostatic bath301, and the temperature of the inside of thethermostatic bath301 is kept to be within a range of −20 to +25° C., for example, around 23° C. Further, although not shown, thebuffet tank102 may also be cooled by use of a Peltier element. With this structure, it is possible to suppress a situation in which ozone is decomposed in thebuffer tank102 before it reaches theprocessing chamber201, then stabilize the supply of the ozone gas into theprocessing chamber201, and suppress waste of ozone.
In addition, ozone reserved into thebuffer tank102 is reacted with the inner wall surface of thebuffer tank102, and is deactivated in some cases. Therefore, the inner wall surface of thebuffer tank102 is coated with a coating film, to thereby suppress the reaction between the inner wall surface of thebuffer tank102 and the ozone gas. For example, oxide films of iron (Fe), titanium (Ti), aluminum (Al), nickel (Ni), or chromium (Cr) (Fe oxide film, Ti oxide film, Al oxide film, Ni oxide film, and Cr oxide film) can be used as the kind of the coating film. It is also acceptable that an inner surface of thebuffer tank102 is coated with a stainless film such as SUS316, or thebuffer tank102 is constituted of stainless steel such as SUS316. In a stainless steel containing chromium, chromium oxide, etc, is easily formed by oxidation processing, and a stable immobility film (oxide film) is thereby formed. Therefore, it is possible to prevent the deactivation of ozone reserved into thebuffer tank102.
Further, the deactivation of ozone is suppressed not only on the inner wall surface of thebuffer tank102, but also in a supply path of the ozone gas, namely, on the inner wall surface of the secondgas supply tube232b. Specifically, the inner wall surface of the secondgas supply tube232bis coated with the aforementioned coating film. In addition, it is also acceptable that the secondgas supply tube232bis constituted of stainless, and the immobility film made of chromium oxide is formed on the inner wall surface of the secondgas supply tube232b.
In addition, in order to form the immobility film made of chromium oxide on the inner wall surface of thebuffer tank102 and the inner wall surface of the secondgas supply tube232b, a coating step is executed, for supplying ozone to the secondgas supply tube232bfrom theozonizer52, in a state of sufficiently removing moisture inside of thebuffer tank102 and the secondgas supply tube232b. At this time, the ozone inlet valve AV1 and the ozone supply valve AV2 are opened, and other valves are closed. As a result, the surface of each part made of stainless is exposed to ozone and oxidized, and on this surface, a stable immobility film made of chromium oxide, etc, is formed. Thus, the deactivation of ozone can be suppressed, and wasteful consumption of ozone can be prevented. In addition, the coating step of forming the immobility film made of chromium oxide on the inner wall surface of thebuffer tank102 and the inner wall surface of the secondgas supply tube232bmay be performed before the substrate processing step as will be described later is started.
(2) Substrate Processing StepNext, the substrate processing step according to this embodiment executed as one of the manufacturing steps of a semiconductor device will be described. The substrate processing step according to this embodiment has an ozone reserving step of reserving ozone into thebuffer tank102 connected to theprocessing chamber201, before the ozone supplying step, and in the ozone supplying step, ozone reserved into thebuffer tank102 is supplied (flush-supplied) pulsatively into theprocessing chamber201, and this point is different from the first and second embodiments. In this embodiment, the ozone filing step, the ozone supplying step, and the ozone removing step are repeated multiple number of times. The substrate processing step according to this embodiment is executed by the substrate processing apparatus shown inFIG. 4. In the following explanation, an operation of each part constituting the substrate processing apparatus is controlled by thecontroller280.
(Wafer Loading Step)First, as described above, thewafer200 is charged into theboat217, and is loaded into theprocessing chamber201. After theboat217 is loaded into theprocessing chamber201, five steps as will be described later are sequentially executed.
(Source Gas Supplying Step (Step1))Instep1, TEMAH gas, being a source gas, is supplied into theprocessing chamber201, while exhausting an atmosphere in theprocessing chamber201 in which thewafer200 is accommodated.
Specifically, thefifth valve243eof theexhaust tube231 is opened, and exhaust of the atmosphere in theprocessing chamber201 is started. Further, the valve AV3 is opened, and the N2gas, being the compressed gas, is supplied to an upper space of the TEMAH stored in thetank305. Moreover, the switchingvalve50 is formed at a source gas supplying position, then the valve AV4 is opened, and TEMAH stored in thetank305 is fed to the vaporizer242 (vaporizingchamber242a) in a compressed state, with its flow rate adjusted by the liquidmass flow controller240, to thereby generate the TEMAH gas. Further, thefirst valve243aof the firstgas supply tube232ais opened, and the N2gas, being the carrier gas, is supplied to the vaporizer242 (vaporizingchamber242a), with its flow rate adjusted by the secondmass flow controller241b. As a result, mixed gas of the TEMAH gas and the carrier gas is supplied into theprocessing chamber201, through the firstgas jet hole248aof the firstgas supply nozzle233a. The TEMAH in the mixed gas supplied into theprocessing chamber201 causes surface reaction (chemical adsorption) with a surface part, etc, of thewafer200, and a base film is formed on thewafer200. An excess portion of the mixed gas not contributing to forming the base film is exhausted from theexhaust tube231 as exhaust gas.
At this time, the opening degree of thefifth valve243eis set, so that the pressure in theprocessing chamber201 is maintained in a range of 0.1 to 400 Pa, for example, 200 Pa. In addition, the flow rate of the TEMAH controlled by the liquidmass flow controller240 is set to be 0.01 to 0.1 g/min, and the time for exposing thewafer200 to the mixed gas is set to be 30 to 180 seconds. Further, the temperature of theheater207 is set, so that the temperature of thewafer200 is set in a range of 180 to 250° C., and for example, 230° C.
(Source Gas Removing Step (Step2))Instep2, the TEMAH gas and the intermediate body of the TEMAH gas remained in theprocessing chamber201 are removed.
Specifically, the switchingvalve50 of thevaporizer242 is formed at a carrier gas supplying position, and the supply of the TEMAH gas into theprocessing chamber201 is stopped. At this time, the inside of theprocessing chamber201 is exhausted until the pressure becomes 20 Pa or less by using thevacuum pump246, with thefifth valve243eof theexhaust tube231 opened, and thethird valve243cof the first carriergas supply tube234ais kept open, until the removal of the residual TEMAH gas and intermediate body of the TEMAH gas from theprocessing chamber201 is completed, and N2, being the purge gas, is supplied into theprocessing chamber201, with its flow rate adjusted by the secondmass flow controller241b. Thus, an effect of removing the residual TEMAH gas and intermediate body of the TEMAH gas from theprocessing chamber201 is further increased.
(Oxide Film Forming Step (Step3))Next, an oxide film forming step (step3) is executed, in which the step of reserving ozone into thebuffer tank102, being a gas reservoir connected to the processing chamber201 (ozone filing step (step3a), the step of supplying into theprocessing chamber201 ozone reserved into the buffer tank102 (step3b), and the step of exhausting the atmosphere of the processing chamber201 (ozone removing step (step3c) are repeated multiple number of times.
Sequence examples 1 to 3 of the oxide film forming step (step3) are respectively shown inFIG. 6 toFIG. 8.
(Sequence Example 1)FIG. 6 shows a sequence example 1 of the oxide film forming step (step3).
In the sequence example 1, as shown in [1] ofFIG. 6, the ozone inlet valve AV1 is opened, with the fifth valve (APC)243eopened, and the ozone supply valve AV2 closed, and ozone gas is supplied into thebuffer tank102, with its flow rate adjusted by the firstmass flow controller241a(ozone reserving step (step3a).
When a prescribed time is elapsed, then a prescribed amount of the ozone gas is reserved into thebuffer tank102, and the pressure in thebuffer tank102 reaches, for example, 100000 Pa, as shown in [2] ofFIG. 6, the ozone supply valve AV2 is opened, and the ozone gas reserved into thebuffer tank102 is supplied into the processing chamber201 (ozone supplying step (step3b). In the ozone supplying step (step3b), the ozone gas reserved into thebuffer tank102 is supplied (flush-supplied) into theprocessing chamber201 pulsatively. The ozone gas causes surface reaction with TEMAH which is chemically adsorbed on the surface of thewafer200, to thereby form the HfO2film on thewafer200. In addition, in the ozone supplying step (step3b), the pressure in theprocessing chamber201 immediately after supplying ozone is set to be, for example, within a range of 0.1 to 1000 Pa.
After a prescribed time is elapsed, ozone and the intermediate body of ozone remained in theprocessing chamber201 are removed (ozone removing step (step3c). Specifically, the ozone supply valve AV2 of the secondgas supply tube232bis closed, and the supply of the ozone gas into theprocessing chamber201 is stopped. At this time, the inside of theprocessing chamber201 is exhausted by thevacuum pump246 until the pressure thereof becomes 20 Pa or less, with thefifth valve243eof theexhaust tube231 opened, and the residual ozone and intermediate body of ozone are removed from theprocessing chamber201. Note that if thefourth valve243dof the second carriergas supply tube234bare opened until removal of the residual ozone and intermediate body of ozone from theprocessing chamber201 is completed and in this state, when N2, being purge gas, is supplied into theprocessing chamber201, with its flow rate adjusted by the thirdmass flow controller241c, the effect of removing the residual ozone and intermediate body of ozone from theprocessing chamber201 can be further increased.
Then, the ozone reserving step (step3a), the ozone supplying step (step3b), and the ozone removing step (step3c) are set as one cycle, and this cycle is repeated multiple number of times.
(Sequence Example 2)FIG. 7 shows a sequence example 2 of the oxide film forming step (step3). In the sequence example 2, the exhaust inside of theprocessing chamber201 is stopped, when the ozone supplying step (step3b) is executed.
In the sequence example 2, first, as shown in [1] ofFIG. 7, the ozone inlet valve AV1 is opened, with the fifth valve (APC)243eopened and the ozone supply valve AV2 closed, and the ozone gas is supplied into thebuffer tank102, with its flow rate adjusted by the firstmass flow controller241a(ozone reserving step (step3a)).
After a prescribed time is elapsed, when a prescribed amount of ozone gas is reserved into thebuffer tank102, and the pressure in thebuffer tank102 reaches, for example, 100000 Pa, as shown in [2] ofFIG. 7, the fifth valve (APC)243eis closed, and the ozone supply valve AV2 is opened, and the ozone gas reserved into thebuffer tank102 is supplied into the processing chamber201 (ozone supplying step (step3b)). In the ozone supplying step (step3b), the ozone gas reserved into thebuffer tank102 is supplied (flush-supplied) into theprocessing chamber201 pulsatively. The ozone gas causes surface reaction with TEMAH which is chemically adsorbed on the surface of thewafer200, to thereby form the HfO2film on thewafer200. In addition, in the ozone supplying step (step3b), the pressure in theprocessing chamber201 immediately after supplying ozone is set to be, for example, within a range of 0.1 to 1000 Pa.
Thereafter, in the same way as the sequence example 1, the ozone removing step (step3c) is executed. Then, the ozone reserving step (step3a), the ozone supplying step (step3b), and the ozone removing step (step3c) are set as one cycle, and this cycle is repeated multiple number of times.
(Sequence Example 3)FIG. 8 shows a sequence example 3 of the oxide film forming step (step3). In the sequence example 3, the opening degree of the fifth valve (APC)243eis adjusted when the ozone supplying step (step3b) is executed, and the ozone gas is supplied into theprocessing chamber201, while adjusting the pressure in theprocessing chamber201 to be an average pressure.
In the sequence example 2, first, as shown in [1] ofFIG. 8, the ozone inlet valve AV1 is opened, with the fifth valve (APC)243eopened and the ozone supply valve AV2 closed, and the ozone gas is supplied into thebuffer tank102, with its flow rate adjusted by the firstmass flow controller241a(ozone reserving step (step3a).
After a prescribe time is elapsed, when a prescribed amount of ozone gas is reserved into thebuffer tank102, and the pressure in thebuffer tank102 reaches, for example, 100000 Pa, as shown in [2] ofFIG. 8, the opening degree of the fifth valve (APC)243eis adjusted, and the ozone supply valve AV2 is opened, to thereby supply into theprocessing chamber201 the ozone gas reserved into the buffer tank102 (ozone supplying step (step3b). In the ozone supplying step (step3b), the ozone gas reserved into thebuffer tank102 is supplied (flush-supplied) into the processing chamber pulsatively. The ozone gas causes surface reaction with TEMAH which is chemically adsorbed on the surface of thewafer200, to thereby form the HfO2film on thewafer200. In addition, in the ozone supplying step (step3b), the pressure in theprocessing chamber201 immediately after supplying ozone is set in a range, for example 0.1 to 1000 Pa.
Thereafter, in the same way as the sequence example 1, the ozone removing step (step3c) is executed. Then, the ozone reserving step (step3a), the ozone supplying step (step3b), and the ozone removing step (step3c) are set as one cycle, and this cycle is repeated multiple number of times.
Note that in any one of the sequence examples, the ozone reserving step (step3a) executed at least in an initial time of repetition is executed simultaneously with the aforementioned source gas supplying step (step1) and/or the source gas removing step (step2). Namely, the step3ais executed simultaneously with the source gas supplying step (step1), simultaneously with the source gas removing step (step2), or simultaneously with the source gas supplying step (step1) and the source gas removing step (step2). In addition, the ozone reserving step (step3a) executed in a second time of repetition may also be executed simultaneously with the ozone removing step (step3c). Namely, after the ozone supplying step (step3b) is executed, the timing of restarting the reserving of the ozone gas into thebuffer tank102 may be set after execution of the ozone supplying step (step3b) is completed.
Further, in any one of the sequence examples, the temperature of the secondgas supply tube232bconnecting thebuffer tank102 and theprocessing chamber201 to a second temperature, while heating thewafer200 to a first temperature (in a range of 180 to 250° C., and for example 230° C.), and further the temperature of thebuffer tank102 is cooled to a third temperature. At this time, the first temperature is set to be higher than the second temperature, and the second temperature is set to be higher than the third temperature. Thus, it is possible to prevent ozone from being decomposed in thebuffer tank102.
(Repeating Step)Thereafter, the aforementioned source gas supplying step (step1) to the oxide film forming step (step3) are set as one cycle, and this cycle is repeated multiple number of times, to thereby form the HfO2film of a prescribed thickness on thewafer200, and the substrate processing step according to this embodiment is ended. Then, thewafer200 after processing is unloaded from theprocessing chamber201, in a reversed procedure to the aforementioned procedure.
Note that in this embodiment, a volume ratio of thebuffer tank102 to theprocessing chamber201 is set to be, for example, 1/2100 to 1/105. For example, when the volume of theprocessing chamber201 is set to be 210 L, the volume of thebuffer tank102 is set to be 0.1 L to 2 L. This is because when the volume ratio becomes under 1/2100, a flow speed of the ozone gas supplied into theprocessing chamber201 pulsatively becomes almost the same as the flow speed of the ozone gas when thebuffer tank102 is not used, and the effect obtained by using thebuffer tank102 is hardly obtained. Also, this is because when the volume ratio exceeds 1/105, the pressure in theprocessing chamber201 becomes too high, when the ozone gas is supplied into theprocessing chamber201 from thebuffer tank102 pulsatively, and this is not preferable.
Further, the pressure of the ozone gas reserved into thebuffer tank102 is set in a range of 200 to 101, 130 Pa, and set to be, for example, 100000 Pa. This is because when the pressure of the ozone gas reserved into thebuffer tank102 becomes under 200 Pa, the flow speed of the ozone gas pulse-supplied into theprocessing chamber201 becomes almost the same as the flow speed of the ozone gas when thebuffer tank102 is not used, and the effect obtained by using thebuffer tank102 is hardly obtained. Also, when the pressure of the ozone gas reserved into thebuffer tank102 exceeds101, 130 Pa, a differential pressure between a pressure of supplying the ozone gas into theprocessing chamber201 and a pressure of the ozone gas reserved into thebuffer tank102, is not taken when the ozone gas is supplied into theprocessing chamber201 pulsatively, thus making it impossible to control the flow rate. This is not preferable.
Further, the pressure in theprocessing chamber201 during executing the ozone supplying step (step3b) is set to be 0.1 to 1000 Pa. This is because when the pressure of theprocessing chamber201 during executing the ozone supplying step (step3b) becomes under 0.1 Pa, ozone supply to the surface of thewafer200 becomes insufficient. Moreover, this is because when the pressure in theprocessing chamber201 during executing the ozone supplying step (step3b) becomes 1000 Pa or more, an exhaust speed of thevacuum pump246 is decreased.
(3) Effect According to this Embodiment
According to this embodiment, one or a plurality of effects as shown below are further exhibited, in addition to the aforementioned effect.
(a) According to this embodiment, the ozone reserving step (step3a) for reserving ozone into thebuffer tank102, being a gas reservoir, is executed, before the ozone supplying step (step3b). Then, in the ozone supplying step (step3b), ozone reserved into thebuffer tank102 is supplied (flush-supplied) into theprocessing chamber201 pulsatively. Thus, a supply amount of ozone to thewafer200 is increased, and delay in oxidation of the base film in the center part of thewafer200 is suppressed. Then, uniformity of the film thickness distribution and the composition distribution of the HfO2film formed on the surface of thewafer200 is improved, and a manufacturing yield of the semiconductor device can be improved.
(b) in addition, according to this embodiment, the supply amount of ozone to thewafer200 is increased, without supplying a large flow rate of the oxide gas containing high density ozone to thewafer200, and delay in oxidation of the base film in the center part of thewafer200 can be suppressed. Therefore, waste of ozone is suppressed, then the cost of processing substrates can be reduced, and throughput (productivity) of processing substrates can be improved.
(c) Further, according to this embodiment, a ribbon heater (not shown), etc, is provided on an outer surface of a supply route of the source gas from the secondary side (outlet) of thevaporizer242 to the processing chamber201 (the upper stream side of the firstgas supply tube232aand the firstgas supply nozzle233a), to thereby heat the source gas to a prescribed temperature (for example, 130° C. when TEMAZ is used as the liquid source). Thus, re-liquefaction of the source gas can be suppressed.
(d) Further, according to this embodiment, the ribbon heater (not shown), etc, is provided on the outer surface of the supply route of the liquid source from thetank305 to thevaporizer242, to thereby heat the liquid source to a prescribed temperature. Thus, vaporization of the liquid source in thevaporizer242 can be accelerated.
(e) Moreover, according to this embodiment, for example as shown inFIG. 15, a coolingcoil300 is provided on the outer surface of thebuffer tank102, then chilling water and a thermal exchange medium such as industrial water, etc, is flown into the coolingcoil300, to thereby cool thebuffer tank102. Thus, temperature increase of the buffer tank due to thermal conduction can be suppressed, and decomposition of ozone in thebuffer tank102 can be suppressed before ozone reaches theprocessing chamber201. Then, supply of the ozone gas into theprocessing chamber201 can be stabilized and waste of ozone can be suppressed.
EXAMPLESFirst, examples 1 to 3 of the present invention will be described together with comparative examples.
FIG. 9 is a table chart explaining examples 1 to 3 of the present invention, together with comparative example 1, showing the film thickness of an average oxidation film, the film thickness of a substrate center part film, and uniformity of the film thickness.
Example 1In this example, the sequence of the oxide film forming step (step3) is the same as the aforementioned sequence example 1 (FIG. 6). Then, the time for reserving the ozone gas into thebuffer tank102 is set to be 3 seconds, the time for flowing the ozone gas into theprocessing chamber201 from thebuffer tank102 is set to be 2 seconds, steps from the ozone reserving step (step3a) to the ozone removing step (step3c) are repeated times, and the time for executing the oxide film forming step (step3) is set to be 180 seconds in total. The flow rate of the O3adjusted by the first mass flow controller (MFC)241aand supplied into thebuffer tank102 is set to be constant 9 slm.
Example 2In this example, the sequence of the oxide film forming step (step3) is the same as the aforementioned sequence example 2 (FIG. 7). Namely, in the ozone supplying step (step3b), the fifth valve (exhaust valve)243eis closed. The other conditions are the same as those of example 1.
Example 3In this example, the sequence of the oxide film forming step (step3) is the same as the aforementioned sequence example 3 (FIG. 8). Namely, in the ozone supplying step (step3b), the opening degree of the fifth valve (exhaust valve)243eis adjusted, and the pressure in theprocessing chamber201 is adjusted to be an average pressure. The other conditions are the same as those of the example 1.
Comparative Example 1In this comparative example, as shown inFIG. 5, the ozone gas is continuously supplied into theprocessing chamber201, without reserving the ozone gas into thebuffer tank102.FIG. 5 is a sequence view of the oxide film forming step according to a comparative example. Namely, the valve AV1 and the valve AV2 are simultaneously opened, and the oxide film is formed without executing the ozone reserving step (step3a) (without supplying the ozone gas pulsatively).
According toFIG. 9, in each case of the examples 1 and 2, the thickness of the HfO2film is larger than that of the comparative example 1, and this reveals that a high film forming speed can be obtained. Also, in each case of the examples 1, 2, 3, the thickness of the HfO2film is larger than that of the comparative example 1 in the center part of thewafer200, and this reveals that the delay in oxidation of the base film in the center part of thewafer200 can be suppressed. Also, in each case of the examples 1, 2, 3, it is found that the uniformity of the film thickness is improved, compared with the comparative example 1. In addition, in the examples 1, 2, it is found that the film forming speed is higher, the film thickness is larger in the center part of thewafer200, and the uniformity of the film thickness is higher than those of example 3.
Next, examples 4 to 6 of the present invention will be described, together with a comparative example 2.
FIG. 10 is a graph chart explaining the examples 4 to 6 of the present invention together with the comparative example 2, whereinFIG. 10A shows a relation between an average film thickness increase amount of the oxide film in the surface of the substrate and an oxidation time, andFIG. 102 shows a relation between the film thickness increase amount of the oxide film in the center part of the substrate and the oxidation time, respectively.
Example 4In this example, the sequence of the oxide film forming step (step3) is the same as the aforementioned sequence example 1 (FIG. 6). Then, the number of repetitions from the ozone filing step (step3a) to the ozone removing step (step3c) is changed, to thereby change the execution time (oxidation time) of the oxide film forming step (step3) in such a manner as 60 seconds, 120 seconds, and 180 seconds.
Example 5In this example, the sequence of the oxide film forming step (step3) is the same as the aforementioned sequence example 2 (FIG. 7). Namely, in the ozone supplying step (step3b), the fifth valve (exhaust valve)243eis closed. Then, the number of repetitions from the ozone reserving step (step3a) to the ozone removing step (step3c) is changed, to thereby change the execution time (oxidation time) of the oxide film forming step (step3) in such a manner as 60 seconds, 120 seconds, and 180 seconds.
Example 6In this example, the sequence of the oxide film forming step (step3) is the same as the aforementioned sequence example 3 (FIG. 8). Namely, in the ozone supplying step (step3b), the opening degree of the fifth valve (exhaust valve)243eis adjusted, to thereby adjust the pressure of theprocessing chamber201 to an average pressure (230 Pa). Then, the steps from the ozone reserving step (step3a) to the ozone removing step (step3c) are repeated, and the oxidation time is set to be 180 seconds.
Comparative Example 2In this comparative example, as shown inFIG. 5, the ozone gas is not reserved into thebuffer tank102 but continuously supplied into theprocessing chamber201.FIG. 5 is a sequence view of the oxide film forming step according to the comparative example. Namely, the valve AV1 and the valve AV2 are simultaneously opened, to thereby form the HfO2film without executing the ozone reserving step (step3a) (without supplying the ozone gas pulsatively). The valve AV1 and the valve AV2 are simultaneously opened, to thereby change the time (oxidation time) for supplying the ozone gas in such a manner as 60 seconds, 120 seconds, and 180 seconds.
According toFIG. 10A, in a case of the comparative example 2, it is found that the oxidation time of about 180 seconds is required for increasing the average film thickness of the HfO2film by 3.5 Å. Meanwhile, in each case of the examples 4, 5, 6 also, it is found that a short oxidation time is enough to increase the average film thickness of the HfO2film by 3.5 Å. For example, it is found that the oxidation time of about 60 seconds is enough in a case of the example 4, to increase the average film thickness of the HfO2film by 3.5 Å, and in a case of the example 5, the oxidation time of about 40 seconds is enough. Namely, in each case of the examples 4 to 6, it is found that a higher film forming speed can be obtained, compared with the comparative example 2.
Further, according toFIG. 10B, in a case of the comparative example 2, even if the oxidation time is increased from 60 seconds to 180 seconds, the thickness of the oxide film in the center part of the substrate is hardly increased (0.1 to 0.2 Å). Meanwhile, in examples 4 and 5, it is found that the thickness of the HfO2film in the center part of thewafer200 is relatively largely increased (1 to 2 Å), by increasing the oxidation time from 60 seconds to 180 seconds. Namely, in each case of the examples 4 and 5 also, the delay of the oxidation of the base film in the center part of thewafer200 can be suppressed.
Next, examples 7 and 8 of the present invention will be described together with the comparative example 3.
FIG. 11 is a table chart describing examples 7 and 8 of the present invention together with the comparative example 3, and showing the average thickness of the HfO2film and the uniformity of the film thickness, in each case of an upper part and a lower part of substrate processing positions.
Example 7In this example, the sequence of the oxide film forming step (step3) is the same as the aforementioned sequence example 2 (FIG. 7). Namely, in the ozone supplying step (step3b), the fifth valve (exhaust valve)243eis closed. Then, by an ALD method wherein the steps from the source gas supplying step (step1) to the oxide film forming step (step3) are set as one cycle, and this cycle is repeated multiple number of times, the HfO2film of a prescribed thickness is formed on the substrate.
Example 8In this example, the sequence of the oxide film forming step (step3) is the same as the aforementioned sequence example 3 (FIG. 8). Namely, in the ozone supplying step (step3b), the opening degree of the fifth valve (exhaust valve)243eis adjusted, to thereby adjust the pressure in theprocessing chamber201 to an average pressure. Then, by the ALD method wherein the steps from the source gas supplying step (step1) to the oxide film forming step (step3) are set as one cycle, and this cycle is repeated multiple number of times, the HfO2film of a prescribed thickness is formed on the substrate.
Comparative Example 3In this comparative example, as shown inFIG. 5, the ozone gas is continuously supplied into theprocessing chamber201, without filing the ozone gas into thebuffer tank102.FIG. 5 is a sequence view of the oxide film forming step according to the comparative example. Namely, the valve AV1 and the valve AV2 are simultaneously opened, and the HfO2film is formed by the ALD method, without executing the ozone filing step (step3a) (without supplying the ozone gas pulsatively).
According toFIG. 11, in each case of the examples 7 and 8 also, it is found that the uniformity of the film thickness is improved, compared with the comparative example 3. Note that the film thickness of the examples 7 and 8, and the film thickness of the comparative example 3 are different from each other. However this is because the number of cycles of ALD is smaller than the number of cycles of ALD of the comparative example 3, and this is not because the film forming speed of the examples 7 and 8 is lower than the film forming speed of the comparative example 3.
Next, examples 9 and 10 of the present invention will be described, together with the comparative example 4.
FIG. 12 is a table chart showing the composition uniformity of the HfO2film in each of the upper part, middle part, and lower part of the substrate processing positions, whereinFIG. 12A shows the composition uniformity of the comparative example 4,FIG. 12B shows the composition uniformity of the example 9, andFIG. 13C shows the composition uniformity of the example 10, respectively. Note that in any one of the cases, evaluation of the composition uniformity is performed by XPS.
Example 9In this example, the sequence of the oxide film forming step (step3) is the same as the aforementioned sequence example 2 (FIG. 7). Namely, in the ozone supplying step (step3b), the fifth valve (exhaust valve)243eis closed. Then, by the ALD method wherein the steps from the source gas supplying step (step1) to the oxide film forming step (step3) are set as one cycle, the HfO2film of a prescribed thickness is formed on the substrate.
Example 10In this example, the sequence of the oxide film forming step (step3) is the same as the aforementioned sequence example 3 (FIG. 8). Namely, in the ozone supplying step (step3b), the opening degree of the fifth valve (exhaust valve)243eis adjusted, to thereby adjust the pressure in theprocessing chamber201 to an average pressure. Then, by the ALD method wherein the steps from the source gas supplying step (step1) to the oxide film forming step (step3) are set as one cycle, the HfO2film of a prescribed thickness is formed on the substrate.
Comparative Example 4In this comparative example, the ozone gas is continuously supplied into theprocessing chamber201, without filing the ozone gas into thebuffer tank102. Namely, the valve AV1 and the valve AV2 are simultaneously opened, and the HfO2film is formed by the ALD method, without executing the ozone reserving step (step3a) (without supplying the ozone gas pulsatively).
According toFIG. 12, in a case of the comparative example 4, it is found that the composition uniformity is deteriorated (deteriorated from ±1.40% to ±3.00%), toward the upper part from the lower part of the substrate processing positions. Namely, in the case of the comparative example 4, it is found that the ozone supply amount to the center part of the wafer is decreased toward the upper part from the lower part of the substrate processing positions. Meanwhile, in each case of the examples 9 and 10, high composition uniformity can be obtained even if the substrate processing positions are changed (±0.9 to ±1.0% in the case of the example 9, and ±1.25% in the case of the example 10). Namely, in either case of the examples 9 and 10, it is found that the ozone supply amount to the center part of the wafer can be prevented from being decreased toward the upper part from the lower part of the substrate processing positions.
Fourth EmbodimentNext, the structure of the substrate processing apparatus according to a fourth embodiment of the present invention, and a substrate processing step executed by this substrate processing apparatus will be described.
(1) Structure of the Substrate Processing ApparatusFirst, the structure of the substrate processing apparatus according to this embodiment will be described, with reference toFIG. 13.FIG. 13 is a schematic block diagram of a processing furnace and a gas supply unit of the substrate processing apparatus according to this embodiment. In this embodiment, the gas supply unit includes a plurality of ozone gas supply routes from theozonizer52 to the secondgas supply nozzle233b, and these plurality of ozone gas supply routes are provided in parallel. This point is a different point from the third embodiment. Note that other structure is the same as the structure of the third embodiment excluding an oxidation sequence of thecontroller280. The structure of the gas supply unit according to this embodiment will be described hereinafter.
As shown inFIG. 13, the lower stream end of the secondgas supply tube232bis connected to the upper stream end of the secondgas supply nozzle233b. The secondgas supply tube232bis branched into a plurality of branch lines (N lines inFIG. 13) in parallel, in the vicinity of a midstream. Each branch line thus branched is merged and unified again on the upper stream side and is connected to theozonizer52. Ozone inlet valves AV1-1 to AV1-N, first mass flow controllers241a-1 to241a-N, buffer tanks102-1 to102-N, being the gas reservoir connected to theprocessing chamber201, and ozone supply valves AV2-1 to AV2-N are respectively provided sequentially from the upper stream side, in each branch line formed by branching the secondgas supply tube232b.
By closing the ozone supply valves AV2-1 to AV2-N, and opening the ozone inlet valves AV1-1 to AV1-N, the ozone gas can be reserved into the buffer tanks102-1 to102-N, while adjusting the flow rate by the first mass flow controllers241a-1 to241a-N. Thereafter, by sequentially opening the ozone supply valves AV2-1 to AV2-N, the ozone gas reserved into the buffer tanks102-1 to102-N can be supplied (flush-supplied) into theprocessing chamber201 pulsatively. Further, by controlling a time interval for opening the ozone supply valves AV2-1 to AV2-N, the time interval for pulse-supply is narrowed, so that an oxidation processing speed can be increased.
(2) Substrate Processing StepNext, the substrate processing step according to this embodiment executed as one of the manufacturing steps of the semiconductor device will be described, with reference toFIG. 14.FIG. 14 is a view exemplifying an operation of the gas supply unit according to this embodiment, and a valve open/close sequence. According to the substrate processing step of this embodiment, in the oxide film forming step (step3), the ozone gas, being the oxide gas, is sequentially supplied (flush-supplied) into theprocessing chamber201 pulsatively, from a plurality of ozone supply routes provided in parallel. This point is a different point from the third embodiment. The substrate processing step according to this embodiment is executed by the substrate processing apparatus shown inFIG. 13. In the following description, the operation of each part constituting the substrate processing apparatus is controlled by thecontroller280.
(Wafer Loading Step to Source Gas Removing Step (Step2))First, in the same way as the aforementioned embodiments, the wafer loading step, the source gas supplying step (step1), and the source gas removing step (step2) are sequentially executed.
(Oxide Film Forming Step (Step3))Next, the oxide film forming step (step3) is executed. Note that in the oxide film forming step (step3) exemplified inFIG. 14, by using an ozone supply system of three systems, the ozone gas is sequentially supplied (flush-supplied) into theprocessing chamber201 pulsatively.
First, as shown in [1] ofFIG. 14, the ozone supply valves AV2-1 to AV2-3, and the ozone inlet valves AV1-2, AV1-3 are closed, then the ozone inlet valve AV1-1 is opened, and the ozone gas is reserved into the buffer tank102-1 while adjusting the flow rate by the first mass flow controller241a-1 (ozone filing step (step3a-1)).
When a prescribed amount of ozone gas is reserved into the buffer tank102-1 after elapse of a prescribed time, and the pressure in the buffer tank102-1 reaches. For example, 100000 Pa, as shown in [2] ofFIG. 14, the ozone inlet valve AV1-1 is closed and the ozone supply valve AV2-1 is opened, and the ozone gas reserved into the buffer tank102-1 is supplied into the processing chamber201 (ozone supplying step (step3b-1)). In the ozone supplying step (step3b-1), the ozone gas reserved into the buffer tank102-1 is supplied (flush-supplied) into theprocessing chamber201 pulsatively. The ozone gas causes surface reaction with TEMAH which is chemically adsorbed on the surface of thewafer200, to thereby form the HfO2film on thewafer200. In addition, in the ozone supplying step (step3b-1), the pressure in theprocessing chamber201 immediately after supplying ozone is set to be, for example, in a range of 0.1 to 1000 Pa.
Also, as shown in [2] ofFIG. 14, in parallel to execution of the ozone supplying step (step3b-1), the ozone inlet valve AV1-2 is opened, and the ozone gas is reserved into the buffer tank102-2, while adjusting the flow rate by the firstmass flow controller241a-(ozone reserving step (step3a-2).
When a prescribed amount of ozone gas is reserved into the buffer tank102-2 after elapse of a prescribed time, and the pressure in the buffer tank102-2 reaches, for example, 100000 Pa, as shown in [3] ofFIG. 14, the ozone inlet valve AV1-2 is closed, and the ozone supply valve AV2-2 is opened, and the ozone gas reserved into the buffer tank102-2 is supplied into the processing chamber201 (ozone supplying step (step3b-2)). In the ozone supplying step (step3b-2), the ozone gas reserved into the buffer tank102-2 is supplied (flush-supplied) into theprocessing chamber201 pulsatively. The ozone gas is chemically adsorbed on the surface of thewafer200, to cause surface reaction with TEMAH, and the HfO2film is formed on thewafer200. Note that in the ozone supplying step (step3b-2), the pressure in theprocessing chamber201 immediately after supplying ozone is set, for example, within a range of 0.1 to 1000 Pa.
Further, as shown in [3] ofFIG. 14, in parallel to execution of the ozone supplying step (step3b-2), the ozone inlet valve AV1-3 is opened, and the ozone gas is reserved into the buffer tank102-3, while adjusting the flow rate by the first mass flow controller241a-3 (ozone reserving step (step3a-3)).
When a prescribed amount of ozone gas is reserved into the buffer tank102-3 after elapse of a prescribed time, and the pressure in the buffer tank102-3 reaches, for example, 100000 Pa, as shown in [4] ofFIG. 14, the ozone inlet valve AV1-3 is closed and the ozone supply valve AV2-3 is opened, and the ozone gas reserved into the buffer tank102-3 is supplied (flush-supplied) into theprocessing chamber201 pulsatively. The ozone gas causes surface reaction with TEMAH which is chemically adsorbed on the surface of thewafer200, to thereby form the HfO2film on thewafer200. In addition, in the ozone supplying step (step3b-3), the pressure in theprocessing chamber201 immediately after supplying ozone is set, for example, within a range of 0.1 to 1000 Pa.
Further, as shown in [4] ofFIG. 14, in parallel to execution of the ozone supplying step (step3b-3), the ozone inlet valve AV1-1 is opened, and the ozone gas is reserved into the buffer tank102-1, while adjusting the flow rate of the first mass flow controller241a-3 (ozone reserving step (step3a-1)).
Thereafter, the steps from the ozone reserving step (step3a-1) to the ozone supplying step (step3b-3) are set as one cycle, and after repeating this cycle multiple number of times, the ozone supplying valves AV2-1 to AV2-3 are closed, to thereby end the oxide film forming step (step3). In addition, during executing and after ending the oxide film forming step (step3), thefifth valve243eof theexhaust tube231 is always opened, to thereby exhaust the inside of theprocessing chamber201 by thevacuum pump246, so that the residual ozone and intermediate body of ozone are removed from theprocessing chamber201. In addition, it is also acceptable that the opening degree of thefifth valve243eis adjusted and the pressure in theprocessing chamber201 is adjusted. Note that when N2being purge gas, is supplied into theprocessing chamber201 until the removal of the residual ozone and intermediate body of ozone from theprocessing chamber201 is completed, the effect of excluding the residual ozone and intermediate body of ozone from theprocessing chamber201 is further increased.
(Repeating Step)Thereafter, the steps from the source gas supplying step (step1) to the oxide film forming step (step3) are set as one cycle, and by repeating this cycle multiple number of times, the HfO2film of a prescribed thickness is formed on thewafer200, and the substrate processing step according to this embodiment is ended. Then, thewafer200 after processing is unloaded from theprocessing chamber201, by a procedure reverse to the wafer loading step.
Note that in this embodiment, the number of supply routes of the ozone gas (the number of buffer tanks102-1 to102N) provided in parallel is decided based on a balance between a processing time and a manufacturing cost required for forming the oxide film.
(3) Effect of this Embodiment
According to this embodiment, one or a plurality of effects shown below are further exhibited, in addition to the aforementioned effects.
(a) According to this embodiment, the time interval of the pulse-supply is narrowed by controlling the time interval for opening the ozone supply valves AV2-1 to AV2-N, to thereby increase the speed of the oxidation processing and it becomes possible to improve the throughput (productivity) of processing substrates.
(b) Further, according to this embodiment, waste of ozone discharged from a vent line is reduced. Therefore, the service life of theozonizer52 can be prolonged, and a running cost can be reduced.
Other Embodiment of the Present InventionAs described above, embodiments of the present invention are specifically described. However, the present invention is not limited to the aforementioned embodiments, and can be variously modified in a range not beyond its gist.
For example, the present invention can be applied to a case of forming films, such as a film other than the HfOxfilm (Si oxide film (SiO), Hf oxide film (HfOx), Zr oxide film (ZrO), Al oxide film, Ti oxide film, Ta oxide film, Ru oxide film, and Ir oxide film).
As the source gas, it is possible to use not only the TEMAH gas obtained by vaporizing tetrakisethylmethyl amino hafnium (TEHAH), being the liquid source which is a liquid at a room temperature, but also the gas obtained by vaporizing other organic metal liquid source such as tetrakisethylmethyl amino zirconium. Also, as the oxide gas, it is possible to use not only ozone (O3), but also other oxygen-containing gas.
Also, as the source gas supplied into theprocessing chamber201, it is possible to use the gas, being a vapor at a room temperature, other than the gas obtained by vaporizing the source, being the liquid at a room temperature by thevaporizer242, depending on the kind of the thin film formed on thewafer200. In such a case, it is also acceptable that the source gas supply source and the mass flow controller (both of them are not shown) are provided, instead of the liquid source supply source, the liquidmass flow controller240, and thevaporizer242. It is also acceptable that the second carriergas supply tube234bis removed, depending on the kind and concentration of the oxide gas supplied into theprocessing chamber201.
Also, third and fourth embodiments show a case in which the substrate processing apparatus is constituted as a normal flow type vertical substrate processing apparatus. However, the substrate processing apparatus is not limited thereto, and may be constituted as a side flow type vertical substrate processing apparatus.FIG. 17 is a schematic block diagram in a case that the gas supply unit according to the third embodiment is applied to the side flow type vertical substrate processing apparatus.
Preferred Aspects of the Present InventionNext, preferred aspects of the present invention will be additionally described.
(Additional Description 1)There is provided a substrate processing method, including the steps of:
supplying source gas into a processing chamber in which substrates are accommodated;
removing the source gas and an intermediate body of the source gas remained in the processing chamber;
supplying ozone into the processing chamber in a sate of substantially stopping an exhaust of an atmosphere in the processing chamber;
removing ozone and the intermediate body of the ozone remained in the processing chamber;
with these steps repeated multiple number of times, to thereby alternately supply the source gas and the ozone so as not to be mixed with each other, and form an oxide film on the surface of the substrate.
Preferably, the source gas is a liquid source at a room temperature and under an atmospheric pressure, and in the source gas supplying step, the source gas is supplied into the processing chamber while exhausting the atmosphere in the processing chamber.
Further preferably, in the ozone supplying step, a pressure in the processing chamber immediately after supplying the ozone is 0.1 to 1000 Pa.
Further preferably, in the ozone supplying step, the ozone is supplied into the processing chamber while adjusting the pressure in the processing chamber to an average pressure.
Further preferably, an ozone filing step for filing the ozone into a gas reservoir connected to the processing chamber is provided before the ozone supplying step, and in the ozone supplying step, the ozone reserved into the gas reservoir is supplied into the processing chamber.
Further preferably, the ozone reserving step is performed simultaneously with the source gas supplying step and/or the source gas removing step. Namely, the ozone reserving step is performed simultaneously with the source gas supplying step, simultaneously with the source gas removing step, or simultaneously with the source gas supplying step and the source gas removing step.
Further preferably, in the ozone reserving step, the ozone is reserved into the gas reservoir, until the pressure in the gas reservoir becomes 100000 Pa.
Further preferably, in each of the steps, the gas supply tube connecting the gas reservoir and the processing chamber is heated to a second temperature, while heating the substrate to a first temperature and further while cooling the gas reservoir to a third temperature, wherein the first temperature is set higher than the second temperature, and the second temperature is set higher than the third temperature.
(Additional Description 2)There is provided the substrate processing method, including the steps of:
supplying source gas into a processing chamber in which substrates are accommodated;
exhausting an atmosphere in the processing chamber;
reserving ozone into a gas reservoir connected to the processing chamber;
supplying into the processing chamber the ozone reserved into the gas reservoir; and
exhausting the atmosphere in the processing chamber;
with these steps repeated multiple number of times, to thereby alternately supply the source gas and the ozone so as not to be mixed with each other, and form an oxide film on the surface of the substrate.
(Additional Description 3)There is provided a substrate processing method, including the steps of:
loading substrates into a processing chamber;
supplying ozone into the processing chamber, in a state of substantially stopping exhaust of an atmosphere in the processing chamber; and
removing the ozone and an intermediate body of the ozone remained in the processing chamber,
with these ozone supplying step and ozone removing step repeated multiple number of times, to thereby form an oxide film on the surface of the substrate.
Preferably, in the ozone supplying step, the pressure in the processing chamber immediately after supplying the ozone is 0.1 to 1000 Pa.
Further preferably, in the ozone supplying step, the ozone is supplied into the processing chamber while adjusting the pressure in the processing chamber to an average pressure.
Further preferably, the ozone reserving step for reserving the ozone into a gas reservoir connected to the processing chamber is provided before the ozone supplying step, and in the ozone supplying step, the ozone reserved into the gas reservoir is supplied into the processing chamber.
Further preferably, in the ozone reserving step, the ozone if reserved into the gas reservoir, until the pressure in the gas reservoir becomes 100000 Pa.
Further preferably, in each of the steps, the gas supply tube connecting the gas reservoir and the processing chamber is heated to a second temperature while heating the substrate to a first temperature and further while cooling the gas reservoir to a third temperature, wherein the first temperature is set higher than the second temperature, and the second temperature is set higher than the third temperature.
(Additional Description 4)There is provided a substrate processing method, including the steps of:
reserving ozone into a gas reservoir connected to a processing chamber in which substrates are accommodated;
supplying into the processing chamber the ozone reserved into the gas reservoir; and
exhausting an atmosphere in the processing chamber;
with these steps repeated multiple number of times, to thereby form an oxide film on the surface of the substrate.
(Additional Description 5)There is provided a substrate processing apparatus, including:
a processing chamber processing a substrate;
a gas supply unit supplying ozone into the processing chamber;
an exhaust unit exhausting an atmosphere in the processing chamber; and
a controller,
with the gas supply unit including an ozone supply path connected to the processing chamber, and an ozone supply valve performing open/close of the ozone supply path.
with the exhaust unit including an exhaust path connected to the processing chamber, and an exhaust valve for opening and closing the exhaust path,
with the controller controlling the gas supply unit and the exhaust unit so that the ozone is supplied into the processing chamber from the ozone supply path in a state of substantially stopping an exhaust of the atmosphere inside of the processing chamber, when the ozone is supplied into the processing chamber.
Preferably, the gas supply unit is disposed on the upper stream side of the ozone supply valve and has a gas reservoir for accumulating ozone, and the controller controls the gas supply unit so as to supply the ozone accumulated in the gas reservoir into the processing chamber by opening the ozone supply valve, after the ozone is supplied into the ozone supply path and the ozone is accumulated in the gas reservoir.
Further preferably, a volume ratio of the gas reservoir to a volume of the processing chamber is 1/2100 to 1/105.
Further preferably, the gas supply unit includes a cooling unit having a cooling medium that cools the gas reservoir.
Further preferably, an inner wall of the gas reservoir is coated with any one of a Fe oxide film, a Ta oxide film, an Al oxide film, a Ni oxide film, and a Cr oxide film.
(Additional Description 6)There is provided a substrate processing apparatus, including:
a processing chamber that accommodates a substrate;
a heating unit disposed outside the processing chamber, for heating an atmosphere and the substrate in the processing chamber;
a gas supply unit that supplies a prescribed gas to the processing chamber;
an exhaust unit that exhausts the atmosphere in the processing chamber; and
a controller that controls at least gas supply operation in the gas supply unit or gas exhaust operation in the exhaust unit,
with the gas supply unit having an ozone supply part for supplying ozone into the processing chamber,
with the ozone supply part having an ozone supply path, a gas reservoir for accumulating ozone, disposed on the ozone supply path on an upper stream side of a connection part of the ozone supply path and the processing chamber, and an ozone supply valve for opening and closing the ozone supply path, disposed on the ozone supply path, being the connection part between the gas reservoir and the processing chamber,
wherein the controller controls the gas supply unit in such manner that, when ozone is supplied into the processing chamber, first, the ozone supply valve is closed, then ozone is flown to the ozone supply path, and a prescribed amount of ozone is accumulated in the gas reservoir, then the ozone supply valve is opened and ozone accumulated in the gas reservoir is supplied to the processing chamber, to thereby form a desired oxide film on the substrate. The pressure in the processing chamber is more reduced than an atmospheric pressure, and an ozone supply accumulating pressure is higher than the pressure in the processing chamber, and substrates are horizontally disposed in the processing chamber in multiple stages. In this state, when the ozone supply valve is opened, ozone is supplied along an upper surface of each substrate pulsatively, and the substrate is processed uniformly in the surface by ozone.
Preferably, there is provided the substrate processing apparatus, wherein the controller controls the gas supply unit, so that a first step of flowing the ozone to the ozone supply path and accumulating a prescribed amount of the ozone in the gas reservoir, and a second step of opening the ozone supply valve and supplying into the processing chamber the ozone accumulated in the gas reservoir are repeated prescribed number of times, when the ozone is supplied into the processing the chamber, to thereby form a desired oxide film on the substrate. Thus, ozone is continuously supplied to the substrate pulsatively. As a result, the substrate is processed uniformly in the surface.
Further preferably, there is provided the substrate processing apparatus, wherein the exhaust unit has an exhaust path; a vacuum exhaust part connected through the exhaust path; and an exhaust valve for opening/closing the exhaust path, with the controller controlling the gas supply unit and the exhaust unit so that the ozone accumulated in the gas reservoir is supplied into the processing chamber from the gas reservoir in a state of stopping exhaust of the processing chamber or extremely squeezing the exhaust of the processing chamber, to thereby form a desired oxide film on the substrate. When the exhaust is stopped or squeezed at the time of oxidizing the substrate by ozone, the substrate is processed uniformly in the surface.
Further preferably, there is provided the substrate processing apparatus, wherein the pressure in the processing chamber immediately after supplying the ozone is set to be 0.1 to 1000 Pa. In a case of the pressure of under 0.1 Pa, uniformity in the surface of the oxide film is lowered, and when the pressure exceeds 1000 Pa, the thickness of the oxide film does not become uniform in the surface. Accordingly, when the oxide film is formed, the pressure in the processing chamber immediately after supplying ozone is set to be 0.1 to 1000 Pa.
Further preferably, there is provided the substrate processing apparatus, wherein the ozone is accumulated in the gas reservoir, until the pressure in the gas reservoir reaches 100000 Pa. When the pressure of the gas reservoir is set to the aforementioned pressure, uniform oxidation and film-formation in the surface of the substrate is possible by ozone supplied to the substrate pulsatively, when the ozone supply valve is opened.
Further preferably, there is provided the substrate processing apparatus, wherein a volume ratio of the gas reservoir to a volume of the processing chamber is 1/2100 to 1/105. Thus, by deciding the volume ratio, the wafer can be uniformly oxidized in the surface and uniform film-formation in the surface is possible.
Further preferably, there is provided the substrate processing apparatus, wherein the controller controls the gas supply unit and the exhaust unit so as to adjust the pressure in the processing chamber to an average pressure when the ozone is supplied into the processing chamber, to thereby form a desired oxide film. Here, the average pressure is the pressure obtained from the pressure for supplying ozone without closing the exhaust valve. When the pressure in the processing chamber is set to be the average pressure, a desired oxide film can be formed uniformly in the surface of the substrate.
Further preferably, there provided the substrate processing apparatus, wherein the exhaust unit is connected to a lower part of the processing chamber. When the exhaust unit is provided in the lower part, source gas (processing gas) can be exhausted after flowing through the processing chamber, and therefore there is no waste of source gas (processing gas). Moreover, the exhaust unit in the lower part is suitable for forming the flow suitable for oxidation and film-formation without disturbing the flow of the gas in the processing chamber.
Further preferably, there is provided the substrate processing apparatus, wherein the processing chamber includes an outer tube and an inner tube set inside of the outer tube, with at least its lower end opened, in which the plurality of substrates are laminated and accommodated, and the gas supply unit has a plurality of gas supply nozzles having gas jet holes erected inside of the inner tube so as to be extended in a laminating direction of the plurality of substrates, and further the processing chamber has a plurality of exhaust ports provided in the inner tube, at positions opposed to the gas supply nozzles.
When the processing chamber is thus constructed, a horizontal flow can be formed on each substrate, and therefore in-surface uniformity of each substrate can be improved. Moreover, both of the processing gas after passing through a gap between the inner tube and the outer tube, and the processing gas from an open end of the inner tube can be exhausted. Therefore, substitution efficiency of the gas can be improved.
Further preferably, there is provided the substrate processing apparatus, wherein the ozone supply part includes a cooling unit having a cooling medium for cooling the gas reservoir.
When this gas reservoir is cooled, the service life of ozone is prolonged, and therefore the substrate can be processed in a state of a constant quality.
Further preferably, there is provided the substrate processing apparatus, wherein the cooling medium is either one of the cooling water and a peltier element. With a simple structure, accumulation of the supplied ozone can be surely cooled, and therefore reliability is improved.
Further preferably, there is provided the substrate processing apparatus, wherein an inner wall of the gas reservoir is coated with any one of a Fe oxide film, a Ti oxide film, an Al oxide film, a Ni oxide film, and a Cr oxide film. Thus, reaction between ozone and cooled reservoir is prevented, and therefore reliability of processing substrates can be improved.
Further preferably, there is provided the substrate processing apparatus, wherein the gas supply unit has a source gas supply part that supplies source gas different from ozone into the processing chamber, and the source gas supply part has a source gas supply path and a source gas supply valve disposed in the source gas supply path, for opening and closing the source gas supply path, and the controller controls the gas supply unit and the exhaust unit so that the source gas and the ozone are alternately repeatedly supplied into the processing chamber multiple number of times so as not to be mixed with each other, and when the source gas is supplied into the processing chamber, the source gas is supplied into the processing chamber from the source gas supply path, and in a state of closing the ozone supply valve, the ozone is flown to the ozone supply path and a prescribed amount of the ozone is accumulated in the gas reservoir, to thereby form a desired oxide film on the substrate.
With this structure, ozone can be accumulated in the gas reservoir while processing the substrate by the source gas. Ozone is supplied to the substrate by opening the ozone supply valve, immediately after ending the processing by the source gas, and the ozone causes reaction with raw materials of the source gas, to thereby oxidize the substrate or form a film thereon.
Further preferably, there is provided the substrate processing apparatus, wherein the oxide film is any one of the Si oxide film, Hf oxide film, Zr oxide film, Al oxide film, Ti oxide film, Ta oxide film, Ru oxide film, and Ir oxide film.
Further preferably, the source gas is any one of an organic compound containing Si atom, Hf atom, Zr atom, Al atom, Ti atom, Ta atom, Ru atom, and Ir atom or chloride of the aforementioned atoms.
Further preferably, there is provided the substrate processing apparatus, wherein the controller further controls the gas supply unit and the exhaust unit so that the remained source gas or ozone is removed, after supply of the source gas into the processing chamber is stopped and after supply of the ozone into the processing chamber is stopped.
Thus, the processing chamber is cleaned.
(Additional Description 7)There is provided a manufacturing method of a semiconductor device, including:
a first step of reserving ozone into a gas reservoir connected to a processing chamber;
a second step of supplying into the processing chamber ozone reserved into the gas reservoir; and
a third step of exhausting an atmosphere in the processing chamber,
with the steps from the first step to the third step repeatedly performed one or more times, to thereby form an oxide film of a prescribed thickness on the surface of a plurality of substrates laminated and accommodated in the processing chamber.
By these steps, the substrate can be processed uniformly in the surface and the oxide film can be formed.
Preferably, there is provided the manufacturing method of the semiconductor device, wherein when the steps from the first step to the third step are repeated, at least one or more first step and third step are simultaneously performed. When ozone is exhausted while being supplied pulsatively, the oxide film can be uniformly formed in the surface.
(Additional Description 8)There is provided the manufacturing method of the semiconductor device for forming the oxide film of a prescribed thickness on the surface of a plurality of substrates laminated and accommodated in a processing chamber by supplying source gas and ozone into the processing chamber alternately and repeatedly prescribed number of times so as not to be mixed with each other, including:
a first step of supplying the source gas into the processing chamber;
a second step of reserving the ozone into a gas reservoir connected to the processing chamber;
a third step of supplying into the processing chamber ozone reserved into the gas reservoir; and
a fourth step of exhausting an atmosphere in the processing chamber,
with the steps from the first step to the fourth step repeated at least one or more times, to thereby form an oxide film of a prescribed thickness on the surface of a plurality of substrates laminated and accommodated in the processing chamber. When these steps are executed, a desired film can be uniformly formed in the surface of the substrate.
Preferably, there is provided the manufacturing method of the semiconductor device, wherein when the steps from the first step to the fourth step are repeated, at least one or more first step and second step are simultaneously performed. With this structure, ozone can be accumulated in the gas reservoir while processing the substrates by the source gas. Ozone is supplied to the substrate, by opening the ozone supply valve immediately after processing by the source gas is ended, and the ozone causes reaction with raw materials of the source gas, to thereby perform oxidation and film-formation.