US20110226418A1 - Method of manufacturing semiconductor device - Google Patents

Abstract

In a dry cleaning process, breakage of a gas supply pipe can be prevented, and maintenance efficiency can be increased. There is provided a substrate processing apparatus comprising: a process chamber configured to process a substrate; a heater configured to heat an inside of the process chamber; a gas supply pipe installed in the process chamber; a gas supply system configured to supply at least a cleaning gas to the gas supply pipe to introduce the cleaning gas into the process chamber; and a control unit configured to control the heater and gas supply system with the substrate unloaded from the process chamber to perform heating an inside of the process chamber to generate a crack in a thin film formed inside the process chamber; decreasing an inside temperature of the process chamber after the crack is generated in the thin film; and introducing the cleaning gas into the process chamber by supplying the cleaning gas to the gas supply pipe after the inside temperature of the process chamber is decreased.

Description

CROSS-REFERENCE TO RELATED PATENT APPLICATION
• The present application is a divisional application of application Ser. No. 12/571,706, filed Oct. 1, 2009; which relates to and claims priority under 35 U.S.C. §119 of Japanese Patent Application No. 2008-260630, filed on Oct. 7, 2008, to the Japanese Patent Office, the entire contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
• 1. Field of the Invention
• The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to a method of manufacturing a semiconductor device by processing a substrate while removing films formed on parts of a semiconductor manufacturing apparatus.
• 2. Description of the Prior Art
• In a process of forming a silicon (Si)-based film by using a hot wall type chemical vapor deposition (CVD) apparatus, source gas and etch gas are supplied to the inside of a reaction furnace through a gas supply pipe. However, when gas is supplied from a gas supply source, films are deposited on quartz components (e.g., a reaction tube, a boat, and the gas supply pipe (including a nozzle)) as well as wafers, and if the thickness of the films exceeds 3 μm, the films may be stripped off and form particles.
• Therefore, it is necessary to clean the quartz components periodically, and moreover, it is necessary to replace the quartz components with new components according to the wear of the quartz components. Wet etching can be performed (to remove Si-based films by using an etchant such as fluoroacetic acid and hydrogen fluoride) each time wafers are processed. However, in this case, since washing and drying processes are also necessary, maintenance time increases, and thus maintenance efficiency decreases. In addition, when a quartz component is detached, the inside of the reaction furnace is exposed to the outside atmosphere and thus can be contaminated. Therefore, it is not preferable to maintain a highly clean state.
• For these reasons, dry etching may be alternatively performed to remove Si-based films by introducing cleaning gas (e.g., ClF₃) into the reaction furnace in a state where the quartz components are disposed in the apparatus in a nitrogen (N₂) atmosphere.
• However, when an Si-based film forming process is performed, since the inside pressure of the gas supply pipe (including a nozzle) used for supplying source gas is higher than the inside pressure of the reaction furnace, a thicker film is deposited on the inside of the source gas supply pipe as compared with the inside of the reaction furnace. Therefore, stresses are accumulated in the gas supply pipe due to the thicker film. If cleaning gas is supplied through the gas supply pipe in which stresses are accumulated, the film deposited on the inside of the gas supply pipe is rapidly etched, and thus the accumulated stresses are rapidly released. This causes breakage of the gas supply pipe such as cracking of the gas supply pipe. Moreover, due to resultant particles and replacement of the gas supply pipe after a dry cleaning process, maintenance efficiency decreases.
SUMMARY OF THE INVENTION
• An object of the present invention is to prevent breakage of a gas supply pipe during a dry cleaning process and improve maintenance efficiency.
• According to an aspect of the present invention, there is provided a substrate processing apparatus comprising: a process chamber configured to process a substrate; a heater configured to heat an inside of the process chamber; a gas supply pipe installed in the process chamber; a gas supply system configured to supply at least a cleaning gas to the gas supply pipe to introduce the cleaning gas into the process chamber; and a control unit configured to control the heater and gas supply system with the substrate unloaded from the process chamber to perform: heating an inside of the process chamber to generate a crack in a thin film formed inside the process chamber; decreasing an inside temperature of the process chamber after the crack is generated in the thin film; and introducing the cleaning gas into the process chamber by supplying the cleaning gas to the gas supply pipe after the inside temperature of the process chamber is decreased.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a schematic view illustrating a substrate processing apparatus.
• FIG. 2 is a schematic view illustrating a processing furnace.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• Preferable embodiments of the present invention will be described hereinafter with reference to the attached drawings.
• A substrate process apparatus relevant to the current embodiment is an example of semiconductor manufacturing apparatuses used for manufacturing semiconductor device integrated circuits (ICs). In the following description, as an example of a substrate processing apparatus, a vertical type apparatus configured to perform a process such as a heat treatment process will be explained.
• FIG. 1 is a schematic view illustrating asubstrate processing apparatus101 according to an embodiment of the present invention.
• As shown inFIG. 1, thesubstrate processing apparatus101 includes agas supply system300, atransfer unit106,cassettes110, aprocess furnace202, aboat217, acontroller240, and avacuum exhaust device246.
• Thecassettes110 are accommodated in thesubstrate processing apparatus101, and each of thecassettes110 holds a plurality ofwafers200 in a state where thewafers200 are arranged and horizontally oriented. Thewafers200 are made of a material such as silicon and have a disk shape.
• Thetransfer unit106 is used to transfer thewafers200 from thecassettes110 to theboat217, or from theboat217 to thecassettes110. For this end, thetransfer unit106 has a wafer pickup structure. That is, thetransfer unit106 is configured to chargewafers200 into theboat217 and discharge thewafers200 from theboat217. Theboat217 is placed under theprocess furnace202 when a film forming process is not performed.
• Theprocess furnace202 includes aheater206 and aprocess tube203. Theheater206 is installed around theprocess tube203 and configured to heat theprocess tube203. Thegas supply system300 is connected to theprocess furnace202 to supply various process gases, and thevacuum exhaust device246 is connected to theprocess furnace202 to evacuate the inside of theprocess furnace202. Theprocess furnace202 will be described later in more detail.
• Thecontroller240 controls operations of thesubstrate processing apparatus101.
• FIG. 2 is a schematic vertical sectional view illustrating theprocess furnace202 of thesubstrate processing apparatus101. InFIG. 2,wafers200 and theboat217 are loaded in aprocess chamber201. Theprocess furnace202 will now be described with reference toFIG. 2.
• As already explained inFIG. 1, theprocess furnace202 includes theheater206 as a heating mechanism. Theheater206 has a cylindrical shape. Theheater206 includes a heating wire and a heat-resistant material disposed around the heating wire. Theheater206 is vertically installed in a state where theheater206 is supported by a holder (not shown).
• Inside theheater206, theprocess tube203 is installed coaxially with theheater206. Theprocess tube203 includes aninner tube204 as an inner reaction tube, and anouter tube205 installed outside theinner tube204 as an outer reaction tube.
• Theouter tube205 is made of a heat-resistant material such as quartz (SiO₂) and silicon carbide (SiC). Theouter tube205 has a cylindrical shape with a closed top side and an opened bottom side.
• Theinner tube204 is made of a heat-resistant material such as quartz (SiO₂) and silicon carbide (SiC). Theinner tube204 has a cylindrical shape with opened top and bottom sides. Theinner tube204 is installed inside theouter tube205. Theinner tube204 and theouter tube205 are coaxial with each other, and the outer diameter of theinner tube204 is smaller than the inner diameter of theouter tube205. Therefore, a cylindrical space250 is formed between theinner tube204 and theouter tube205. The top side of theinner tube204 is spaced downward from the ceiling of theouter tube205, and the top side of ahollow region212 of theinner tube204 communicates with the top side of the cylindrical space250.
• Under theinner tube204 and theouter tube205, a manifold209 is installed. The manifold209 is made of a metal such as stainless steel. The manifold209 has a cylindrical shape with opened top and bottom sides.
• Amiddle plate210 is formed on the inside of the manifold209 at a vertical center position, and apenetration hole211 is formed through a center part of themiddle plate210.
• The manifold209 has the same diameter as that of theouter tube205. The top side of the manifold209 is connected to the bottom side of theouter tube205, and theouter tube205 is supported by the manifold209. Theinner tube204 is installed in a state where theinner tube204 is erected on themiddle plate210, and thepenetration hole211 is positioned inside the diameter of theinner tube204. An O-ring is installed between theouter tube205 and the manifold209 as a seal member. The manifold209 is supported by a holder (not shown) so that theprocess tube203 can be vertically installed.
• A reaction vessel is constituted by theprocess tube203 and the manifold209. Theprocess chamber201 formed in the reaction vessel is divided into thehollow region212 of theinner tube204, the cylindrical space250 formed between theinner tube204 and theouter tube205, and a lower-side space213 (hollow region) of the manifold209 located under themiddle plate210.
• Under the manifold209, a seal cap219 is installed as a furnace port cover for air-tightly closing the opened bottom side of the manifold209. The seal cap219 is made of a metal such as stainless steel and has a cylindrical shape. On the top surface of the seal cap219, an O-ring is installed as a seal member making contact with the bottom side of the manifold209.
• At the seal cap219, arotary mechanism254 is installed. A rotation shaft255 of therotary mechanism254 is connected to theboat217 through the seal cap219. Therotary mechanism254 is configured to rotatewafers200 by rotating theboat217. The seal cap219 is configured to be vertically lifted and lowered by a lift motor248 installed outside theprocess furnace202 as a lift mechanism. By this, theboat217 can be loaded into and out of theprocess chamber201. A drivingcontrol unit237 is electrically connected to therotary mechanism254 and a boat elevator115 so as to perform a desired operation at a desired time.
• Theboat217 used as a substrate holding unit is made of a heat-resistant material such as quartz (SiO₂) and silicon carbide (SiC). Theboat217 is configured to hold a plurality of wafers200 (for example, fifty to one hundred fifty wafers200) in a state where thewafers200 are horizontally oriented and are arranged in multiple stages with centers of thewafers200 being aligned. At the lower part of theboat217, a plurality of insulatingplates216, which are made of a heat-resistance material such as quartz (SiO₂) and silicon carbide (SiC) and have a disk shape, are horizontally oriented and arranged in multiple stages so as to prevent heat transfer from theheater206 to the manifold209.
• In addition, atemperature sensor263 is installed inside theinner tube204.
• Atemperature control unit238 is electrically connected to theheater206 and thetemperature sensor263 so as to control power supplied to theheater206 based on temperature information detected using thetemperature sensor263, so that desired temperature distribution can be obtained inside theprocess chamber201 at a desired time.
• Agas supply pipe165, a gas supply pipe167, and fourgas supply pipes166 are installed at the manifold209. Thegas supply pipes165,166, and167 extend from an outside area of the manifold209 to the inside of theprocess chamber201 through the manifold209. Downstream end parts of thegas supply pipes165,166, and167 are configured as nozzles.
• The downstream end part of thegas supply pipe165 is located in the lower-side space213 of the manifold209. The upstream side of thegas supply pipe165 is connected to a directional control valve331. The directional control valve331 is three-port directional control valve. A first port of the directional control valve331 is connected to thegas supply pipe165. A second port of the directional control valve331 is connected to a raw-materialgas supply source301 through a valve321 and a mass flow controller (MFC)311, and the second port of the directional control valve331 is also connected to a dilutegas supply source302 through a valve322 and anMFC312. A third port of the directional control valve331 is connected to an inertgas supply source305 through a valve325 and anMFC315, and the third port of the directional control valve331 is also connected to a cleaning gas supply source306 through avalve326 and an MFC316. The directional control valve331 has first and second switching positions (two switching positions). If the directional control valve331 is switched to the first switching position, thegas supply pipe165 is connected to the valve321 and the valve322, and when the directional control valve331 is switched to the second switching position, thegas supply pipe165 is connected to the valve325 and thevalve326.
• The downstream end part of one of the fourgas supply pipes166 is located in the lower-side space213, and the downstream end parts of the other threegas supply pipes166 are located at different heights in thehollow region212 of theinner tube204. The upstream sides of thegas supply pipes166 are connected to first ports of directional control valves333. Second ports of the directional control valves333 are connected to a raw-materialgas supply source303 through valves323 andMFCs313. Third ports of the directional control valves333 are connected to the inertgas supply source305 through the valve325 and theMFC315, and the third ports of the directional control valves333 are also connected to the cleaning gas supply source306 through thevalve326 and the MFC316. Each of the directional control valves333 has first and second switching positions (two switching positions). If the directional control valves333 are switched to the first switching positions, thegas supply pipes166 are connected to the valves323, and if the directional control valves333 are switched to the second switching positions, thegas supply pipes166 are connected to the valve325 and thevalve326.
• The downstream end part of the gas supply pipe167 is located in the lower-side space213. The upstream side of the gas supply pipe167 is connected to a first port of a directional control valve334. A second port of the directional control valve334 is connected to a etchgas supply source304 through a valve324 and an MFC314. A third port of the directional control valve334 is connected to the inertgas supply source305 through the valve325 and theMFC315, and the third port of the directional control valve334 is also connected to the cleaning gas supply source306 through thevalve326 and the MFC316. The directional control valve334 has first and second switching positions (two switching positions). If the directional control valve334 is switched to the first switching position, the gas supply pipe167 is connected to the valve324, and if the directional control valve334 is switched to the second switching position, the gas supply pipe167 is connected to the valve325 and thevalve326.
• Silane gas such as monosilane (SiH₄) is filled in the raw-materialgas supply source301. Dilute gas such as hydrogen gas and helium gas is filled in the dilutegas supply source302. Germanium-based gas such as monogermane gas (GeH₄) is filled in the raw-materialgas supply source303. Etch gas such as chlorine gas and hydrogen chloride gas is filled in the etchgas supply source304. Inert gas such as nitrogen gas and argon gas is filled in the inertgas supply source305. Cleaning gas such as Chlorine trifluoride (ClF₃) is filled in the cleaning gas supply source306.
• The MFCs311 to316 are gas flowrate control devices configured to detect and control gas flowrates.
• A gas flowrate control unit235 is electrically connected to the MFCs311 to316 and the valves321 to326 so to control gas supply, so that gas can be supplied with a desired flowrate at a desired time. The gas flowrate control unit235 is electrically connected to the directional control valves331,333, and334, so as to control switching positions of the directional control valves331,333, and334.
• Agas exhaust pipe231 is installed at the manifold209 and is connected to the cylindrical space250. Thevacuum exhaust device246 such as a vacuum pump is connected to the downstream side of thegas exhaust pipe231 through a pressure sensor243 used as a pressure detector and an automatic pressure control (APC) valve242 used as a pressure regulator. A pressure control unit236 is electrically connected to the pressure sensor243 and the APC valve242, and the opened degree of the APC valve242 is adjusted based on pressure information detected using the pressure sensor243, so that the inside pressure of theprocess chamber201 can be adjusted to a desired level at a desired time.
• The gas flowrate control unit235, the pressure control unit236, the drivingcontrol unit237, and thetemperature control unit238 constitute a manipulation unit and an input/output unit and are electrically connected to a main control unit239 configured to control the overall operation of thesubstrate processing apparatus101. Thecontroller240 is constituted by the gas flowrate control unit235, the pressure control unit236, the drivingcontrol unit237, thetemperature control unit238, and the main control unit239.
• Next, a method of manufacturing a semiconductor device will be described together with main operations of the above-describedsubstrate processing apparatus101. In the following description, respectively parts of thesubstrate processing apparatus101 are controlled by thecontroller240.
• Substrate processing operations will now be described.
• When a plurality ofcassettes110 is carried into thesubstrate processing apparatus101 by an in-plant carrying device (not shown), thetransfer unit106charges wafers200 into theboat217 from the cassettes110 (wafer charging). After thetransfer unit106transfers wafers200 to theboat217, thetransfer unit106 goes back to thecassettes110 for transferring thenext wafers200 to theboat217.
• After a predetermined number ofwafers200 are charged into theboat217, thecontroller240 controls the drivingcontrol unit237 to initiate a lifting operation of the boat elevator115. Then, theboat217 in which a group ofwafers200 are held is loaded into theprocess furnace202 by the lifting operation of the boat elevator115 (boat loading), the opened bottom side of the manifold209 is closed by the seal cap219. In this way, thecontroller240 operates the boat elevator115 through the drivingcontrol unit237.
• Next, thecontroller240 controls the pressure control unit236 to operate thevacuum exhaust device246, and then the inside of theprocess chamber201 is evacuated to a desired pressure (vacuum degree) by thevacuum exhaust device246. At this time, the inside pressure of theprocess chamber201 is measured using the pressure sensor243, and based on the measured pressure, the APC valve242 is feedback-controlled by the pressure control unit236 of thecontroller240.
• In addition, thecontroller240 controls thetemperature control unit238 to operate theheater206, and thus the inside of theprocess chamber201 is heated to a desired temperature by theheater206. At this time, to obtain desired temperature distribution inside theprocess chamber201, power to theheater206 is feedback-controlled by thetemperature control unit238 of thecontroller240 based on temperature information detected by thetemperature sensor263.
• Next, thecontroller240 controls the drivingcontrol unit237 to operate therotary mechanism254. Then, theboat217 is rotated by therotary mechanism254, and thus thewafers200 held in theboat217 can be rotated. The operation of therotary mechanism254 is continued.
• Next, thecontroller240 controls the gas flowrate control unit235 to switch the directional control valve331 for connecting thegas supply pipe165 to the valves321 and322. Similarly, the directional control valves333 and334 are switched so that thegas supply pipes166 can be connected to the valves323 and the gas supply pipe167 can be connected to the valve324.
• Thereafter, thecontroller240 controls the gas flowrate control unit235 so as to set the flowrates of the MFCs311 to314 to predetermined values and open the valves321 to324. Then, a mixture of silane gas and dilute gas is introduced into theprocess chamber201 through thegas supply pipe165, germanium-based gas is introduced into theprocess chamber201 through thegas supply pipes166, and etching gas is introduced into theprocess chamber201 through the gas supply pipe167. The gases introduced into theprocess chamber201 flow upward in thehollow region212 of theinner tube204 and enter the cylindrical space250 through the opened top side of theinner tube204. Then, the gases are discharged from the cylindrical space250 through thegas exhaust pipe231. When the gases flows through theprocess chamber201, the gases make contact with thewafers200 so that epitaxial silicon germanium (Epi-SiGe) films can be selectively grown on the surfaces of thewafers200. In addition, films (e.g., Epi-SiGe films) are grown on components such as theinner tube204 and theouter tube205. Such films are also grown on the inner walls of thegas supply pipes165,166, and167.
• Alternatively, thecontroller240 may close the valves323 and open the valves321,322, and324. In this case, germanium-based gas is not introduced into theprocess chamber201, and thus Epi-Si films may be selectively grown on the surfaces of thewafers200. If thesubstrate processing apparatus101 is used to form only Epi-Si films onwafers200, the raw-materialgas supply source303, theMFCs313, the valves323, the directional control valves333, and thegas supply pipes166 are not installed.
• Alternatively, thecontroller240 may close the valve324 and open the valves321,322, and323. In this case, etch gas is not introduced into theprocess chamber201, and thus poly-SiGe films may be deposited on the surfaces of thewafers200.
• Alternatively, thecontroller240 may close the valves323 and324 and open the valves321 and322. In this case, etch gas and germanium-based gas are not introduced into theprocess chamber201, and thus Epi-Si films may be deposited on the surfaces of thewafers200.
• After a predetermined time interval from the instruction of the gases, thecontroller240 closes the valves321 to324. Thereafter, thecontroller240 switches the directional control valves331,333, and334. Then, thegas supply pipe165 is connected to the valve325 through the directional control valve331, thegas supply pipes166 are connected to the valve325 through the directional control valves333, and the gas supply pipe167 is connected to the valve325 through the directional control valve334.
• After that, thecontroller240 sets the flowrate of theMFC315 to a predetermined value and opens the valve325. Then, inert gas is introduced into theprocess chamber201 from the inertgas supply source305 through thegas supply pipes165,166, and167. As a result, the inside atmosphere of theprocess chamber201 is replaced with the inert gas, and at the same, the inside pressure of theprocess chamber201 returns to atmospheric pressure.
• Next, thecontroller240 controls the drivingcontrol unit237 to stop therotary mechanism254 and initiate a lowering operation of the boat elevator115. As the seal cap219 and theboat217 are moved downward by the lowering operation of the boat elevator115, the bottom side of the manifold209 is opened, and at the same time, theboat217 in which thewafers200 are held is unloaded from the process chamber201 (boat unloading). Thereafter, thetransfer unit106 transfers the processedwafers200 from theboat217 to thecassettes110. Thecassettes110 in which the processedwafers200 are placed are carried to the outside of thesubstrate processing apparatus101 by the in-plant carrying device (not shown).
• Thereafter, the above-described substrate processing operations are repeated for processing thenext wafers200 sequentially. When the above-described substrate processing operations are repeated, a cleaning operation is performed on theprocess furnace202. The cleaning operation is performed each time the above-described substrate processing operations are repeated once or a predetermined number of times. Hereinafter, the cleaning operation will now be described in detail.
• In a state where nowafer200 is placed in theboat217 after processedwafers200 are transferred from theboat217 tocassettes110, thecontroller240 initiate the lifting operation of the boat elevator115.
• Next, thecontroller240 switches the directional control valves331,333, and334. Then, thegas supply pipe165 is connected to thevalves325 and326 through the directional control valve331, thegas supply pipes166 are connected to thevalves325 and326 through the directional control valves333, and the gas supply pipe167 is connected to thevalves325 and326 through the directional control valve334.
• Next, thecontroller240 keeps the valve325 opened. In addition, the opened degree of the APC valve242 is feedback-controlled by thecontroller240 based on pressure information detected and input by the pressure sensor243. Then, inert gas is introduced into theprocess chamber201 to fill the inside of theprocess chamber201 at a pressure of 50 Pa to 500 Pa.
• Next, thecontroller240 controls thetemperature control unit238 to operate theheater206 for heating theprocess chamber201 and parts of thegas supply pipes165,166, and167 placed inside theprocess chamber201. At this time, thecontroller240 inputs a temperature measured by thetemperature sensor263 for feedback-controlling theheater206 and keeping the rate of temperature increase caused by theheater206 within the range of 10° C./min to 30° C./min. Preferably, theprocess chamber201 may be heated to a temperature of 750° C. to 800° C. in 30 minutes from the initiation of heating.
• During the temperature increasing process, thecontroller240 compares a temperature detected by thetemperature sensor263 with an upper threshold value (ranging from 600° C. to 900° C., preferably, from 750° C. to 800° C.). If the temperature of theprocess chamber201 and thegas supply pipes165,166, and167 increases to a temperature of 600° C. to 900° C. (preferably, 750° C. to 800° C.), thecontroller240 recognizes that a temperature detected by thetemperature sensor263 reaches the upper threshold value, and thecontroller240 stops or lowers the heating operation of theheater206. Then, the temperature of theprocess chamber201 and thegas supply pipes165,166, and167 is decreased. If thegas supply pipes165,166, and167 are heated to a temperature of 600° C. to 900° C. as described above, cracks are generated in films formed on the insides of thegas supply pipes165,166, and167, and thus residual stresses of thegas supply pipes165,166, and167 are reduced. Owing to the same reason, cracks are generated in films formed on theboat217, theinner tube204, and theouter tube205, and thus residual stresses of theboat217, theinner tube204, and theouter tube205 are reduced.
• During the temperature lowering process, thecontroller240 compares a temperature detected by thetemperature sensor263 with an lower threshold value (ranging from 350° C. to 550° C.). If the temperature of theprocess chamber201 and thegas supply pipes165,166, and167 decreases to a temperature of 350° C. to 550° C., thecontroller240 recognizes that a temperature detected by thetemperature sensor263 reaches the lower threshold value. Then, thecontroller240 sets the flowrate of theMFC315 to a value of 1000 sccm to 4500 sccm and the flowrate of the MFC316 to a value of 500 sccm to 2500 sccm. In addition, thecontroller240 keeps thevalves325 and326 opened.
• Then, cleaning gas and inert gas are introduced into theprocess chamber201 through thegas supply pipes165,166, and167. Since cleaning gas flows through thegas supply pipes165,166, and167, films formed on the insides of thegas supply pipes165,166, and167 are removed by dry etching. As described above, since the films are previously heated to form cracks in the films, the residual stresses of thegas supply pipes165,166, and167 are not greatly varied by the removing of the films. Therefore, thegas supply pipes165,166, and167 can be prevented from being damaged during the film etching process.
• The cleaning gas and inert gas introduced into theprocess chamber201 flow upward in thehollow region212 of theinner tube204 and enter the cylindrical space250 through the opened top side of theinner tube204. Then, the gases are discharged from the cylindrical space250 through thegas exhaust pipe231. Since cleaning gas flows through theprocess chamber201 in this way, films formed on theboat217, theinner tube204, and theouter tube205 can be etched away.
• While the cleaning gas and inert gas are introduced, the flowrate of the cleaning gas is adjusted to the set value of 500 sccm to 2500 sccm of the MFC316, and the flowrate of the inert gas is adjusted to the set valve of 1000 sccm to 4500 sccm of theMFC315. The inert gas is used to dilute the cleaning gas.
• In addition, while the cleaning gas and inert gas are introduced, thecontroller240 inputs a pressure detected by the pressure sensor243 and adjusts the opened degree of the APC valve242 based on the detected pressure by feedback controlling. In this way, the inside of theprocess chamber201 is kept at a pressure of 50 Pa to 500 Pa.
• In addition, while the cleaning gas and inert gas are introduced, thecontroller240 inputs a temperature detected by thetemperature sensor263 and controls power supplied to theheater206 based on the detected temperature by feedback controlling (isothermal controlling). In this way, the inside of theprocess chamber201 is kept at a temperature of 350° C. to 550° C.
• After a predetermined time from the introduction of the cleaning gas and inert gas through thevalves325 and326 which are kept opened by thecontroller240, thevalve326 is closed by thecontroller240. As a result, cleaning gas is not supplied, and only inert gas is supplied to the inside of theprocess chamber201, so that the inside atmosphere of theprocess chamber201 is replaced with inert gas and the inside pressure of theprocess chamber201 returns to atmospheric pressure.
• Next, quartz components (theinner tube204, theouter tube205, theboat217, and thegas supply pipes165,166, and167 including nozzles) of thesubstrate processing apparatus101 are coated with silicon (Si). By this coating, substrates can be prevented from being contaminated by quartz during a processing process.
• Next, thecontroller240 controls the pressure control unit236 to operate thevacuum exhaust device246, and then the inside of theprocess chamber201 is evacuated to a desired pressure (vacuum degree) by thevacuum exhaust device246. At this time, the inside pressure of theprocess chamber201 is measured using the pressure sensor243, and based on the measured pressure, the APC valve242 is feedback-controlled by the pressure control unit236 of thecontroller240.
• In addition, thecontroller240 controls thetemperature control unit238 to operate theheater206, and thus the inside of theprocess chamber201 is heated to a desired temperature by theheater206. At this time, to obtain desired temperature distribution inside theprocess chamber201, power to theheater206 is feedback-controlled by thetemperature control unit238 of thecontroller240 based on temperature information detected by thetemperature sensor263.
• Next, thecontroller240 controls the drivingcontrol unit237 to operate therotary mechanism254. Then, theboat217 is rotated by therotary mechanism254, and thus thewafers200 held in theboat217 can be rotated. The operation of therotary mechanism254 is continued.
• Next, thecontroller240 controls the gas flowrate control unit235 to switch the directional control valve331 so as to connecting thegas supply pipe165 to the valves321 and322. Thereafter, thecontroller240 controls the gas flowrate control unit235 to set the flowrates of theMFCs311 and312 to predetermined values and open the valves321 and322. Then, a mixture of silane gas and dilute gas is introduced into theprocess chamber201 through thegas supply pipe165. The silane gas and dilute gas introduced into theprocess chamber201 flow upward in thehollow region212 of theinner tube204 and enter the cylindrical space250 through the opened top side of theinner tube204. Then, the silane gas and inert gas are discharged from the cylindrical space250 through thegas exhaust pipe231. When the gases flow through theprocess chamber201, the gases makes contact with quartz components of thesubstrate processing apparatus101. Therefore, the quartz components are previously coated with silicon (Si) as described above.
• Next, thecontroller240 initiates the lowing operation of the boat elevator115. Then, the seal cap219 and theboat217 are moved downward by the boat elevator115.
• Thereafter, the above-described substrate processing processes are performed again.
• According to the above-described embodiment of the present invention, a temperature increasing process is performed prior to introduction of cleaning gas so as to generate cracks in films formed on thegas supply pipes165,166, and167 by raw-material gas, so that stresses remaining in thegas supply pipes165,166, and167 can be reduced. Therefore, although the films are rapidly etched away from thegas supply pipes165,166, and167 by cleaning gas, stresses remaining in thegas supply pipes165,166, and167 are not rapidly released. Thus, breakage and deterioration of thegas supply pipes165,166, and167 can be prevented. As a result, generation of particles caused by breakage of thegas supply pipes165,166, and167 can be prevented, and thegas supply pipes165,166, and167 can be less frequently replaced. Accordingly, the maintenance of thesubstrate processing apparatus101 can be easily performed, and thus, maintenance costs and time can be reduced.
• In addition to thegas supply pipes165,166, and167, theboat217, theinner tube204, and theouter tube205 can also be prevented from being damaged and deteriorated by etching.
• In the above-described embodiment, after Si-based poly silicon films are formed, a cleaning process is performed using ClF₃gas. However, the present invention can be applied to the case where a cleaning process is performed using F₂gas after SiN-based films are formed by an atomic layer deposition (ALD) method or a chemical vapor deposition (CVD) method using gas and surface reactions.
• In addition, the heating process prior to the introduction of cleaning gas may be performed by directly heating thegas supply pipes165,166, and167 using a heater fixed to thegas supply pipes165,166, and167. Furthermore, a temperature sensor fixed to thegas supply pipes165,166, and167 may be used. Similarly, a heater or a temperature sensor may be fixed to the surfaces of theboat217, theinner tube204, and theouter tube205.
• According to the present invention, prior to supply of cleaning gas to the inside of the process chamber, the inside of the process chamber is heated to a temperature higher than a temperature at which the process chamber is kept when cleaning gas is supplied to the inside of the process chamber. Therefore, stresses caused by films formed on the inside of the substrate processing apparatus can be gradually removed, so that breakage of nozzles can be prevented. Accordingly, generation of particles caused by breakage of the nozzles can be reduced, and thus maintenance efficiency can be improved.
• While preferred aspects and embodiments of the present invention have been described, the present invention also includes the following embodiments.
• (Supplementary Note 1)
• According to a preferred embodiment of the present invention, there is provided a method of manufacturing a semiconductor device, the method including: loading a substrate into a process chamber; forming a silicon film or a silicon compound film on the substrate loaded in the process chamber by supplying a raw-material gas to a gas supply pipe disposed in the process chamber to introduce the raw-material gas into the process chamber; unloading the substrate from the process chamber; heating an inside of the process chamber; decreasing an inside temperature of the process chamber after the heating of the inside of the process chamber; and introducing a cleaning gas into the process chamber by supplying the cleaning gas to the gas supply pipe after the decreasing of the inside temperature of the process chamber.
• (Supplementary Note 2)
• In the method of Supplementary Note 1, the inside of the process chamber is heated to a temperature of 600° C. to 900° C. in the heating of the inside of the process chamber; the inside temperature of the process chamber is decreased to a temperature of 350° C. to 550° C. in the decreasing of the inside temperature of the process chamber; and the inside temperature of the process chamber is kept in a range from 350° C. to 550° C. in the introducing of the cleaning gas into the process chamber.
• (Supplementary Note 3)
• According to another preferred embodiment of the present invention, there is provided a substrate processing apparatus including: a process chamber configured to process a substrate; a heater configured to heat an inside of the process chamber; a gas supply pipe installed in the process chamber; a gas supply system configured to supply at least a cleaning gas to the gas supply pipe for introducing the cleaning gas into the process chamber; and a control unit configured to perform a process of heating the inside of the process chamber by using the heater, a temperature decreasing process of stopping the heater or decreasing heat generated by the heater after the process of heating the inside of the process chamber, and a process of supplying a cleaning gas to the gas supply pipe by using the gas supply system after the temperature decreasing process.
• (Supplementary Note 4)
• The substrate processing apparatus of Supplementary Note 3, further includes a temperature detecting unit connected to detect an inside temperature of the process chamber, wherein if the control unit recognizes a temperature detected by the temperature detecting unit and ranging from 600° C. to 900° C. during the process of heating the inside of the process chamber, the control unit performs the temperature decreasing process, and if the control unit recognizes a temperature detected by the temperature detecting unit and ranging from 350° C. to 550° C. during the temperature decreasing process, the control unit performs the process of supplying the cleaning gas to the gas supply pipe.
• (Supplementary Note 5)
• According to another preferred embodiment of the present invention, there is provided a method of cleaning a substrate processing apparatus including: a process chamber configured to process a substrate; a gas supply pipe installed in the process chamber; and a gas supply system configured to supply a cleaning gas to the gas supply pipe for introducing the cleaning gas into the process chamber, the method including: heating an inside of the process chamber; decreasing an inside temperature of the process chamber after the heating of the inside of the process chamber; and introducing a cleaning gas into the process chamber by supplying the cleaning gas to the gas supply pipe after the decreasing of the inside temperature of the process chamber.
• (Supplementary Note 6)
• In the method of Supplementary Note 5, the inside of the process chamber is heated to a temperature of 600° C. to 900° C. in the heating of the inside of the process chamber; the inside temperature of the process chamber is decreased to a temperature of 350° C. to 550° C. in the decreasing of the inside temperature of the process chamber; and the inside temperature of the process chamber is kept in a range from 350° C. to 550° C. in the introducing of the cleaning gas into the process chamber.
• (Supplementary Note 7)
• According to another preferred embodiment of the present invention, there is provided a method of cleaning a substrate processing apparatus including: a process chamber configured to process a substrate; a gas supply pipe installed in the process chamber; and a gas supply system configured to supply a cleaning gas to the gas supply pipe for introducing the cleaning gas into the process chamber, the method including: heating the gas supply pipe; decreasing a temperature of the gas supply pipe after the heating of the gas supply pipe; and introducing a cleaning gas into the process chamber by supplying the cleaning gas to the gas supply pipe after the decreasing of the temperature of the gas supply pipe.
• (Supplementary Note 8)
• In the method of Supplementary Note 7, the gas supply pipe is heated to a temperature of 600° C. to 900° C. in the heating of the gas supply pipe; the temperature of the gas supply pipe is decreased to a temperature of 350° C. to 550° C. in the decreasing of the temperature of the gas supply pipe; and an inside temperature of the process chamber is kept in a range from 350° C. to 550° C. in the introducing of the cleaning gas into the process chamber.

Claims (2)

1. A substrate processing apparatus comprising:

a process chamber configured to process a substrate;

a heater configured to heat an inside of the process chamber;

a gas supply pipe installed in the process chamber;

a gas supply system configured to supply at least a cleaning gas to the gas supply pipe to introduce the cleaning gas into the process chamber; and

a control unit configured to control the heater and gas supply system with the substrate unloaded from the process chamber to perform heating an inside of the process chamber to generate a crack in a thin film formed inside the process chamber;

decreasing an inside temperature of the process chamber after the crack is generated in the thin film; and

introducing the cleaning gas into the process chamber by supplying the cleaning gas to the gas supply pipe after the inside temperature of the process chamber is decreased.

2. The apparatus ofclaim 1, further comprising:

a temperature sensor for sensing the inside temperature of the process chamber,

wherein the control unit performs decreasing the inside temperature of the process chamber when the inside temperature of the process chamber sensed by the temperature sensor ranges from 600° C. to 900° C., and performs introducing the cleaning gas into the process chamber when the inside temperature of the process chamber sensed by the temperature sensor ranges from 350° C. to 550° C.

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