US20040025786A1 - Substrate processing apparatus and reaction container - Google Patents

Abstract

A substrate processing apparatus comprises a reaction chamber which is to accommodate stacked substrates, a gas introducing portion, and a buffer chamber, wherein the gas introducing portion is provided along a stacking direction of the substrates, and introduces substrate processing gas into the buffer chamber, the buffer chamber includes a plurality of gas-supply openings provided along the stacking direction of the substrates, and the processing gas introduced from the gas introducing portion is supplied from the gas-supply openings to the reaction chamber.

Description

BACKGROUND OF THE INVENTION
• 1. Field of the Invention[0001]
• The present invention relates to a substrate processing apparatus and a reaction container, more particularly, to a substrate processing apparatus and a reaction container used in one step of producing process of a semiconductor device for processing a substrate in a reaction chamber, and more particularly, to an improvement of a gas introducing portion which supplies gas to a substrate.[0002]
• 2. Description of the Related Art[0003]
• A conventional technique for processing a substrate in a reaction chamber by a CVD (Chemical Vapor Deposition) method or an ALD (Atomic Layer Deposition) method will be briefly explained with reference to FIG. 14 while taking a vertical type substrate processing apparatus as an example.[0004]
• FIG. 14 is a schematic sectional view of the inside of a reaction tube which is a reaction chamber in the conventional vertical type substrate processing apparatus.[0005]
• A plurality of[0006]wafers107 are stacked on a boat108 as substrates to be processed. The boat108 is inserted into areaction tube106. Agas nozzle101 as a gas introducing portion for processing thewafers107 in thereaction tube106 is provided in thereaction tube106.
• The[0007]gas nozzle101 is provided with a plurality of gas nozzle holes103 (five in the example shown in FIG. 14). With this arrangement, processing gas flows into thegas nozzle101 from a gas introducing opening105, and is supplied to thewafers107 from thegas nozzle holes103.
• The gas supplied to each[0008]wafer107 passes through a process for forming a desired film on thewafer107 and then, is discharged out from thereaction tube106 through anexhaust opening118.
• However, when all of the[0009]gas nozzle holes103 provided in thegas nozzle101 have the same opening areas, there is a problem that a flow rate and flow velocity of gas supplied from thegas nozzle holes103 to thewafers107 are reduced from an upstream side closer to the gas introducing opening105 toward a downstream side further from theopening105.
• That is, if the apparatus for collectively processing the plurality of[0010]wafers107 shown in FIG. 14 is considered from a viewpoint of gas supply with respect to each of the wafers, it seems that thegas nozzle101 supplies gas uniformly to thewafers107, but in reality, a difference in the gas flow rate or flow velocity is generated, and the gas is not supplied to all of thewafers107 under the same conditions.
• For example, if the five[0011]gas nozzle holes103 provided in thegas nozzle101 are defines as a first hole, a second hole, . . . and a fifth hole from the upstream side closer to the gas introducing opening105 of thegas nozzle101 toward the downstream further from theopening105, and if the flow rates of gas supplied from the respectivegas nozzle holes103 are defined as q1, q2 . . . q5, a relation of q1>q2> . . . >q5 is established.
• Concerning the flow velocities of gas also, a velocity of gas from the first[0012]gas nozzle holes103 is the fastest, and velocities of gas from the second, third, . . . are gradually reduced.
• As a result, the flow rates and flow velocities of gas supplied to the[0013]wafers107 become nonuniform.
• Therefore, in the process of wafers which largely depends of a supply amount of gas, the film forming states of the[0014]stacked wafers107 become nonuniform.
• Referring back to FIG. 14, a cause of the nonuniformity of the supply amount of gas will be considered.[0015]
• In the[0016]gas nozzle101 in a state in which gas is supplied to thewafers107, a gas flow rate between the introducing opening105 and the firstgas nozzle hole103 is defined as q00 and a gas pressure therebetween is defined as p0. Next, a gas flow rate between the first and secondgas nozzle holes103 is defined as q01 and a gas pressure therebetween is defined as p1. Similarly, a gas flow rate between the n−1-th and n-thgas nozzle holes103 is defined as q0(n−1) and a gas pressure therebetween is defined as pn−1.
• A flow rate of gas injecting from the n-th[0017]gas nozzle hole103 is defined as qn.
• At that time, gas flow rates qn (n=1, 2, . . . ) injecting from the plurality of[0018]gas nozzle holes103 provided from the upstream side to the downstream side and having the same opening areas are reduced from the upstream gas nozzle hole toward the downstream gas nozzle hole as shown in the following expression (1):
• q1>q2> . . . >qn−1>qn  (1).
• This is because, in the case of gas flowing from the upstream side toward the downstream side through the[0019]gas nozzle101, its gas flow rate q0(n−1) is reduced by a gas flow rate qn injecting from thegas nozzle hole103 when the gas passes through thegas nozzle hole103, and the gas flows toward a next gas nozzle hole. A flow rate of gas after the gas passed through thegas nozzle hole103 is reduced from the upstream side toward the downstream side as shown in the following expression (2):
• q0n=q0(n−1)−qn  (2)
• At that time, a gas concentration of fluid in the[0020]gas nozzle101 is reduced by a flow rate of gas injecting from the gas holes from the upstream side toward the downstream side. Since there is a correlation between the gas concentration and gas pressure, a gas pressure pn at a location in thegas nozzle101 corresponding to thegas nozzle hole103 is reduced from the upstream side toward the downstream side as shown in the following expression (3):
• p1>p2> . . . >pn−1>pn  (3)
• Therefore, flow rates of gas injecting from the respective[0021]gas nozzle holes103 do not become equal to each other. If an opening area of thegas nozzle hole103 is defined as S, a flow velocity V of gas injecting from the gas nozzle hole is expressed as shown in the following expression (4):
• V=qn/S  (4)
• Since the flow rates of gas injected from the respective[0022]gas nozzle holes103 are not equal to each other, if the opening areas of the nozzle holes are the same, flow velocities of gas injected from the respectivegas nozzle holes103 become different. In the above-describedconventional gas nozzle101, since the flow rates and flow velocities of gas injected from the respectivegas nozzle holes103 are different, it is considered that gas can not be supplied to the wafers uniformly.
• To solve the above problem, two conventional solutions have been proposed.[0023]
• According to a first solution, opening areas of the[0024]gas nozzle hole103 are increased from the upstream side toward the downstream side, and a gas flow rate which is reduced toward the downstream side is supplemented by increasing the opening area. However, if the gas flow rates are equalized by adjusting the opening areas, the gas flow velocities are adversely varied depending upon the size of the opening area. Therefore, gas injecting from thegas nozzle holes103 is nonuniform in the flow velocity.
• According to a second solution, a capacity of the gas nozzle itself is increased to such a degree that such a large amount of gas that the injecting amount can be ignored is stored so that even if gas is injected from the[0025]gas nozzle holes103 from the upstream side toward the downstream side, gas pressures in thegas nozzle101 at locations corresponding to the respectivegas nozzle holes103 are not changed, thereby equalizing the flow rates of gas injecting from thegas nozzle holes103. However, if the capacity of the gas nozzle itself is increased to such a size that the gas pressure in thegas nozzle101 is not affected by the gas injecting amount, since there is limitation in space of the reaction chamber which accommodates the gas nozzle, this is not practical.
• The above problem is not limited to a wafer, and a substrate in general also has the same problem.[0026]
SUMMARY OF THE INVENTION
• Thereupon, it is a main object of the present invention to provide, from a viewpoint different from the above structure, a substrate processing apparatus capable of achieving the uniformity of process between substrates by uniformly supplying gas.[0027]
• According to a first aspect of the present invention, there is provided a substrate processing apparatus, comprising:[0028]
• a reaction chamber which is to accommodate stacked substrates,[0029]
• a gas introducing portion, and[0030]
• a buffer chamber, wherein[0031]
• the gas introducing portion is provided along a stacking direction of the substrates, and introduces substrate processing gas into the buffer chamber,[0032]
• the buffer chamber includes a plurality of gas-supply openings provided along the stacking direction of the substrates, and the processing gas introduced from the gas introducing portion is supplied from the gas-supply openings to the reaction chamber.[0033]
• According to a second aspect of the present invention, there is provided a substrate processing apparatus, comprising:[0034]
• a reaction chamber which is to accommodate stacked substrates,[0035]
• a plurality of buffer chambers, and[0036]
• a plurality of gas introducing portions for respectively introducing substrate processing gases to the buffer chambers, wherein[0037]
• the buffer chambers respectively include a plurality of gas-supply openings provided in a stacking direction of the substrates, and the substrate processing gas introduced from each of the gas introducing portions is supplied to the reaction chamber from the gas-supply openings of each of the buffer chambers.[0038]
• According to a third aspect of the present invention, there is provided a reaction container, comprising:[0039]
• a reaction chamber which is to accommodate stacked substrates,[0040]
• a plurality of buffer chambers, and[0041]
• a plurality of gas introducing portions for respectively introducing substrate processing gases to the buffer chambers, wherein[0042]
• the buffer chambers respectively include a plurality of gas-supply openings provided in a stacking direction of the substrates, and the substrate processing gas introduced from each of the gas introducing portions is supplied to the reaction chamber from the gas-supply openings of each of the buffer chambers.[0043]
• According to a forth aspect of the present invention, there is provided a reaction container, comprising:[0044]
• a reaction chamber which is to accommodate stacked substrates,[0045]
• a gas introducing portion, and[0046]
• a buffer chamber, wherein[0047]
• the gas introducing portion is provided along a stacking direction of the substrates, and introduces substrate processing gas into the buffer chamber,[0048]
• the buffer chamber includes a plurality of gas-supply openings provided along the stacking direction of the substrates, and the processing gas introduced from the gas introducing portion is supplied from the gas-supply openings to the reaction chamber.[0049]
BRIEF DESCRIPTION OF THE DRAWINGS
• The above and further objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, wherein:[0050]
• FIG. 1 is a schematic sectional view of a inside of a reaction tube of a substrate processing apparatus according to a first embodiment of the present invention;[0051]
• FIG. 2A is a schematic lateral sectional view of a reaction tube of a substrate processing apparatus according to a first embodiment of the present invention;[0052]
• FIG. 2B is a longitudinal sectional view taken along a line aa′ of FIG. 2A;[0053]
• FIG. 3A is a perspective view of a gas nozzle according to a first embodiment of the present invention;[0054]
• FIG. 3B is a perspective view of a buffer chamber according to a first embodiment of the present invention;[0055]
• FIG. 4 is a schematic view for explaining a mechanism of a vertical type substrate processing apparatus according to embodiments of the present invention;[0056]
• FIG. 5A is a view showing an outward appearance of a reaction tube of a substrate processing apparatus according to a second embodiment of the present invention;[0057]
• FIG. 5B is a schematic longitudinal sectional view of a reaction tube of a substrate processing apparatus according to a second embodiment of the present invention;[0058]
• FIG. 5C is a schematic longitudinal partial sectional view of a reaction tube of a substrate processing apparatus according to a second embodiment of the present invention;[0059]
• FIG. 6 is a lateral sectional view taken along a line A-A of FIG. 5A;[0060]
• FIG. 7 is a lateral sectional view of a reaction tube of a substrate processing apparatus according to a third embodiment of the present invention;[0061]
• FIG. 8 is a lateral sectional view of a reaction tube of a substrate processing apparatus according to a forth embodiment of the present invention;[0062]
• FIG. 9 is a lateral sectional view of a reaction tube of a substrate processing apparatus according to a fifth embodiment of the present invention;[0063]
• FIG. 10 is a lateral partial sectional view of a reaction tube of a substrate processing apparatus according to a sixth embodiment of the present invention;[0064]
• FIG. 11 is a lateral partial sectional view of a reaction tube of a substrate processing apparatus according to a seventh embodiment of the present invention;[0065]
• FIG. 12 is a lateral partial sectional view of a reaction tube of a substrate processing apparatus according to a eighth embodiment of the present invention;[0066]
• FIG. 13 is a lateral sectional view of a reaction tube of a substrate processing apparatus according to a ninth embodiment of the present invention; and[0067]
• FIG. 14 is a schematic sectional view of a inside of a reaction tube of a substrate processing apparatus according to a conventional technique.[0068]
DESCRIPTION OF THE PREFERRED EMBODIMENTS
• According to a preferred embodiment of the present invention, there is provided a substrate processing apparatus comprises[0069]
• a reaction chamber which is to accommodate stacked substrates,[0070]
• a gas introducing portion, and[0071]
• a buffer chamber, wherein[0072]
• the gas introducing portion is provided along a stacking direction of the substrates, and introduces substrate processing gas into the buffer chamber,[0073]
• the buffer chamber includes a plurality of gas-supply openings provided along the stacking direction of the substrates, and the processing gas introduced from the gas introducing portion is supplied from the gas-supply openings to the reaction chamber.[0074]
• With this structure, the substrate processing apparatus according to the present invention, nonuniform flow velocity of gas supplied from the gas introducing portion can be equalized in the buffer chamber, and gas can be supplied to the stacked substrates uniformly.[0075]
• Preferably, opening areas of the gas-supply openings provided in the buffer chamber are substantially equal to each other.[0076]
• It is possible to further equalize the gas supply to the substrates by providing the gas-supply openings having the same opening areas.[0077]
• Preferably, the buffer chamber is provided therein with electrodes for generating plasma.[0078]
• Since the electrodes for generating plasma are provided in the buffer chamber, active species are produced by plasma at a location close to the substrates and in a state in which pressure is uniform, and uniform and more active species can be supplied to the substrates.[0079]
• Next, embodiments of the present invention will be explained with reference to the drawings.[0080]
• First, as an example of process for a substrate carried out in the embodiment of the invention, film forming processing using the CVD method and the ALD method will briefly be explained based on a comparison the methods.[0081]
• In the CVD method, one kind (or more kinds) of gases which are raw material used for forming a film are mixed and supplied onto a substrate under a certain film forming condition (temperature, time or the like), the gas is adsorbed and reacted on the substrate using both vapor-phase reaction and surface reaction, or only surface reaction, thereby forming a film.[0082]
• According to the ALD method, two kinds (or more kinds) of gases which are raw material used for forming a film are alternately supplied onto a substrate one kind gas by one kind gas under a certain film forming condition (temperature, time or the like), the gas is adsorbed in one atomic layer unit, and a film is formed utilizing the surface reaction.[0083]
• That is, when a SiN (silicon nitride) film is to be formed for example, in the case of the ALD method, DCS (dichlorsilane) and NH[0084]₃(ammonia) are used for carrying out chemical reaction to be utilized, and a film having high quality can be formed at a low temperature of 300 to 600C.°. Whereas, in the case of a normal CVD method, a film forming temperature is relatively high as high as 600 to 800C.°. In the case of the ALD method, a plurality of kinds of reaction gases are alternately supplied one kind gas by one kind gas (not at the same time), and in the case of the normal CVD method, a plurality of kinds of gases are supplied at the same time. In the ALD method, a film thickness is controlled based on the number of cycles of supply of reaction gas (assuming that a film forming velocity is 1 Å/cycle for example, when a film of 20 Å is to be formed, the processing is carried out through 20 cycles), and in the CVD method, a film thickness is controlled based on time.
• An embodiment of the present invention will be explained with reference to FIGS.[0085]1 to13.
• The same elements are designated with the same symbols in FIGS.[0086]1 to13.
• First, an outline of a mechanism of a vertical type substrate processing apparatus of each of embodiments of the present invention will be briefly explained using FIG. 4.[0087]
• FIG. 4 shows an outward appearance of an example of a vertical type substrate processing apparatus in which a plurality of wafers which are substrates to be processed and which have diameter of 200 mm are loaded in a reaction tube which is a reaction chamber and made of quartz, and films are formed by the CVD method or the ALD method which is one of the CVD method as processing method.[0088]
• The vertical type substrate processing apparatus has a[0089]body60 and autility portion61 which supplies electric power or the like to thebody60.
• In the[0090]body60, there are provided areaction tube6 as a vertical type reaction chamber for processing wafers, and aheater16 for appropriately heating thereaction tube6. Aboat8 for loading and unloading the wafers into and from thereaction tube6, and aboat elevator36 for vertically moving theboat8 are disposed below thereaction tube6.
• If it is necessary to produce plasma in the[0091]reaction tube6,electrodes52 are provided in thereaction tube6, high frequency electric power is applied to theelectrodes52 from a highfrequency power supply51 through anRF matching unit53.
• Further, provided in the[0092]body60 arecassette shelves34 for temporarily storing cassettes in which wafers to be supplied to theboat8 are accommodated, and awafer transfer apparatus38 for supplying wafers which are not yet processed (pre-process wafers, hereinafter) from thecassette shelves34 to theboat8 and for transferring out wafers which were processed (post-process wafers, hereinafter).
• A[0093]cassette loader35 transfers acassette32 between thecassette shelves34 and an I/O stage33 which receives and delivers thecassette32 of the wafer from and to outside.
• The I/[0094]O stage33 is disposed on a front surface of the apparatus, and delivers and receives thecassette32 accommodating wafers to and from outside.
• The operation of the above-described vertical type substrate processing apparatus will be explained briefly.[0095]
• The[0096]cassettes32 accommodating the wafers are set to the I/O stage33.
• The[0097]cassettes32 set in the I/O stage33 are transferred to thecassette shelves34 by thecassette loader35 in succession.
• In the[0098]cassette32,25 wafers are accommodated.
• The[0099]wafer transfer apparatus38 transfers the wafers out from thecassette shelves34 and transfers the same to thequartz boat8. Since 100 wafers can be loaded into theboat8, the transfer operation by thewafer transfer apparatus38 is repeated several times.
• If the transfer operation of the wafers to the[0100]boat8 is completed, theboat8 is moved upward by theboat elevator36 and inserted into thereaction tube6 and then, the inside of thereaction tube6 is held air-tightly.
• The gas is exhausted from the[0101]reaction tube6 through an exhaust opening (not shown) using a pump, and if a pressure in thereaction tube6 reaches a predetermined value, theboat8 is rotated by a rotating mechanism (not shown), and film-forming processing gas of a certain flow rate is supplied into thereaction tube6. A pressure of the supplied processing gas is maintained at a constant value by a pressure adjusting mechanism (not shown). At that time, the wafers in thereaction tube6 are maintained at a predetermined temperature.
• The process for forming films on the wafers is proceeded in this manner, and further details thereof will be described later.[0102]
• If the film is formed by a plasma CVD method or the ALD method, high frequency electric power is applied to the[0103]electrodes52 from the highfrequency power supply51 through theRF matching unit53, plasma is produced in the film-forming gas, and the film-forming gas is activated. This activating operation will also be described later.
• If the process for forming film is completed, the[0104]wafer boat8 is moved down from thereaction tube6 by theboat elevator36, thewafer boat8 is transferred to the I/O stage33 through thewafer transfer apparatus38, thecassette shelves34 and thecassette loader35, and transferred out from the apparatus.
• Next, embodiments using the above-described vertical type substrate processing apparatus will be explained.[0105]
• (First Embodiment)[0106]
• Embodiment Using CVD Method for Film Forming Process[0107]
• FIG. 2A is a schematic lateral sectional view of the reaction tube in the vertical type substrate processing apparatus according to this embodiment, and FIG. 2B is a vertical sectional view taken along a line a-a′ in FIG. 2A.[0108]
• In FIG. 2A, a[0109]heater16 is provided on an outer periphery of thereaction tube6 which is a vertical type reaction chamber. A plurality ofwafers7 as substrates to be processed are stacked and placed in thereaction tube6. In an arc space between thewafers7 and an inner wall of thereaction tube6, abuffer chamber17 is provided on an inner wall of thereaction tube6 from its lower portion to its upper portion along a stacking direction of thewafers7. Buffer chamber holes3 as gas-supply openings are provided in an end of a wall of thebuffer chamber17 which is adjacent to thewafer7. The buffer chamber holes3 are opened toward a center of thereaction tube6.
• An end of the[0110]buffer chamber17 which is opposite from the buffer chamber holes3 is provided with agas nozzle2 formed in the gas introducing portion from the lower portion to the upper portion of thereaction tube6 along the stacking direction of thewafers7. Thegas nozzle2 is provided with a plurality of gas nozzle holes4.
• As shown in FIG. 2B, an outer periphery of the[0111]reaction tube6 is covered with theheater16. Thereaction tube6 is supported on afurnace opening flange25. A furnace opening of thefurnace opening flange25 is air-tightly closed with afurnace opening cap27.
• The[0112]boat8 is provided in a central portion in thereaction tube6. The plurality ofwafers7 are placed in theboat8 at equal distances from one another in a multistage manner. Theboat8 can come into and go out from thereaction tube6 by the boat elevator. In order to enhancing the uniformity of the processing, theboat8 is provided at its lower portion with arotating mechanism15 for rotating theboat8.
• When the[0113]boat8 enters thereaction tube6 to form films on thewafers7, thewafers7 placed in the multistage manner are placed at an equal distance from thebuffer chamber17.
• The[0114]buffer chamber17 is provided along the inner wall of thereaction tube6, thegas nozzle2 is disposed in thebuffer chamber17 from the lower portion to the upper portion of a side surface of thereaction tube6, and a portion of thegas nozzle2 at the lower portion becomes agas introducing opening5.
• The[0115]gas nozzle2 and thebuffer chamber17 are provided with the gas nozzle holes and the buffer chamber holes, respectively. Examples of opening states of these holes will be explained using FIGS. 3A and 3B.
• FIG. 3A is a perspective view of the gas nozzle shown in FIGS. 2A and 2B. FIG. 3B is a perspective view of the buffer chamber also shown in FIGS. 2A and 2B.[0116]
• The[0117]gas nozzle2 shown in FIG. 3A is a pipe having a circular cross section. The gas nozzle holes4 are straightly arranged in a side surface of thegas nozzle2 from its substantially uppermost portion to a bottom of thebuffer chamber17 from an upstream side toward a downstream side of gas flow. Opening areas of the gas nozzle holes4 are increased from the upstream side (lower portion in FIG. 3A) toward the downstream side (upper portion in FIG. 3A) as viewed from the gas introducing opening.
• The[0118]buffer chamber17 shown in FIG. 3B is a pipe having an arc cross section. The buffer chamber holes3 having the same opening areas are straightly arranged in an end of a curve inner surface of thebuffer chamber17 along the stacking direction of thewafers7.
• Referring back to FIG. 2B, the[0119]reaction tube6 is provided at its lower portion with anexhaust opening18 connected to an exhaust pump (not shown).
• The film forming process by the CVD method on the[0120]wafer7 in thereaction tube6 will be explained with reference to FIGS. 2A and 2B.
• The processing gas which is raw material is supplied to the[0121]gas nozzle2 from thegas introducing opening5. Thegas nozzle2 is provided with the plurality of gas nozzle holes4, and thegas nozzle2 injects gas into thebuffer chamber17. As described as the conventional solution, however, it is difficult to uniform the flow rate and the flow velocity of gas injected from the plurality of gas nozzle holes4 by controlling only the opening areas of the gas nozzle holes4.
• Thereupon, in the present invention, the opening areas of the gas nozzle holes[0122]4 are increased from the upstream side toward the downstream side. With this arrangement, gas of substantially the same flow rate is injected from each of the gas nozzle holes4 although there is a difference in the flow velocity of gas. Then, the gas injected from the gas nozzle holes4 is not injected into thereaction tube6, but the gas once injected and introduced into thebuffer chamber17, and the flow velocities of the gas are uniformed.
• That is, the gas injected from each the gas nozzle holes[0123]4 in thebuffer chamber17 is moderated in the particle velocity of gas in thebuffer chamber17 and then, is injected into thereaction tube6 from the buffer chamber holes3. During that time, kinetic energies of the gas injected from the gas nozzle holes4 are exchanged and thus, when the gas is injected from the buffer chamber holes3, gas having the uniform flow rate and flow velocity can be injected.
• The equalizing operation of the gas supply amount in the[0124]buffer chamber17 will be explained in more detail using FIG. 1.
• FIG. 1 is a schematic sectional view showing a relation between the gas nozzle, the buffer chamber and the reaction tube in the reaction tube of the vertical type substrate processing apparatus of the invention.[0125]
• In FIG. 1, the[0126]buffer chamber17 is provided in thereaction tube6. Thegas nozzle2 is disposed in thebuffer chamber17, and thereaction tube6 is provided with theexhaust opening18 for exhausting gas in thereaction tube6 to outside.
• In the[0127]reaction tube6, theboat8 having wafers7 (five wafers in FIG. 1) is provided adjacent to thebuffer chamber17.
• The[0128]gas nozzle2 and thebuffer chamber17 are respectively provided with the gas nozzle holes4 and the buffer chamber holes3 (five each in FIG. 1). The opening areas of the gas nozzle holes4 are increased from the upstream side toward the downstream side as viewed from thegas introducing opening5 so that the injecting amounts of gas from the gas nozzle holes4 become the same.
• With this structure, if the gas nozzle holes[0129]4 of thegas nozzle2 are respectively defined as the first, second . . . fifth gas nozzle hole from the upstream side closer to the introducingopening5 toward the downstream side further from the introducingopening5, and if the flow rates of gas supplied from the respective gas nozzle holes4 are respectively defined as Q1, Q2 . . . Q5, it is possible to obtain a state of Q1=Q2= . . . =Q5.
• In the flow velocities of gas as explained in the conventional solution, however, gas from the first gas nozzle hole[0130]4 is the fastest, and the flow velocity is gradually reduced in the order of the second, third, forth and fifth gas nozzle holes.
• Gas having the same flow rates but different flow velocities Q1 to Q5 is once introduced into the[0131]buffer chamber17. During that time, gas having the flow velocities Q1 to Q5 is uniformed in flow velocity by exchanging kinetic energies, and a pressure in thebuffer chamber17 is substantially equalized.
• As a result, if the flow rates of gas injected from the buffer chamber holes[0132]3 are respectively defined as R1, R2 . . . R5, even if the buffer chamber holes3 have the same opening areas, since the pressure in thebuffer chamber17 is uniform, a state of R1=R2= . . . =R5 can be obtained, and the flow velocities become equal to each other.
• Further, the opening positions of the buffer chamber holes[0133]3 have the same pitches as thewafers7 which are respectively adjacent to the buffer chamber holes.3, and the gas is supplied to gaps between thewafers7. Therefore, gas having uniform flow velocities and flow rates can efficiently be supplied to thewafers7 preferably.
• Since the gas having uniform flow velocities and flow rates can efficiently be supplied to the[0134]wafers7, the film forming states of thewafers7 are equalized, and the processing speed of thewafers7 can largely be enhanced.
• Although the gas nozzle and the buffer chamber are described in the above explanation based on the CVD method, the invention can also be applied based on the ALD method also.[0135]
• (Second Embodiment)[0136]
• Embodiment Using ALD Method for Film Forming Process[0137]
• An embodiment for forming films by the ALD method will be explained concretely.[0138]
• When films are formed on the[0139]wafers7 by the ALD method also, the above-described vertical type substrate processing apparatus can be used. In the case of the ALD method, however, if it is required to activate the processing gas by plasma or the like, an apparatus and an operation required for this process are added.
• A case for forming films by the ALD method will be explained below using FIGS. 5A, 5B and[0140]5C and FIG. 6.
• FIGS. 5A, 5B and[0141]5C show, from a side, an outward appearance and the inside of the reaction tube which is the reaction chamber in the vertical type substrate processing apparatus of the invention used for forming films by the ALD method. FIG. 6 is a lateral sectional view taken along a line A-A.
• FIG. 5A shows the outward appearance of the reaction chamber. FIGS. 5B and C are vertical sectional views of the reaction chamber. In the drawings, connected portions of the furnace opening flange with respect to the heater, the wafers, the boat and the reaction tube, as well as the boat rotating mechanism are omitted.[0142]
• In FIG. 6, the[0143]reaction tube6 is provided at its outer periphery with aheater16, and the plurality ofwafers7 as substrates to be processed are stacked inside thereaction tube6. Thebuffer chamber17 is provided in the arc space between thewafers7 and the inner wall of thereaction tube6 along the stacking direction of thewafers7 to the inner wall of thereaction tube6, and the buffer chamber holes3 are provided in the end of the wall which is adjacent to the wafers.
• The[0144]reaction tube6 is provided at its lower portion with theexhaust opening18.
• In the reaction tube explained in FIG. 2A, the gas nozzle is provided in the end which is opposite from the buffer chamber hole in the buffer chamber. In this embodiment, a[0145]gas supply chamber43 is provided as the gas introducing portion in the reaction tube instead of the gas nozzle. Thegas supply chamber43 is provided at its lower portion with thegas introducing opening5.
• A partition wall between the[0146]gas supply chamber43 and thebuffer chamber17 is provided with gas supply chamber holes47 having the same structure as that of the gas nozzle holes provided in the above-described gas nozzle. The opening positions of the buffer chamber holes3 provided in thebuffer chamber17 have the same pitches as those of theadjacent wafers7.
• As a result, like the first embodiment, gas is once introduced from the gas introducing portion, and gas can be supplied to the[0147]stacked wafers7 uniformly.
• In this embodiment, the[0148]electrode52 is disposed in thebuffer chamber17 such that theelectrode52 is protected by an electrode-protectingtube50 from its upper portion to lower portion. Theelectrode52 is connected to the highfrequency power supply51 through theRF matching unit53. As a result, theelectrode52 can generateplasma14 in thebuffer chamber17.
• In addition, in this embodiment, a reaction[0149]gas buffer chamber42 is provided on an inner wall of thereaction tube6 at a location away from the opening of thebuffer chamber hole3 through 120° along the inner periphery of thereaction tube6. This reactiongas buffer chamber42 contains gas different from that contained in thebuffer chamber17. When the films are to be formed by the ALD method, the reactiongas buffer chamber42 and thebuffer chamber17 supply different kinds of gases to thewafers7 alternately.
• Like the[0150]buffer chamber17, the reactiongas buffer chamber42 has reaction gas buffer chamber holes48 with the same pitches at locations adjacent to the wafers. The reactiongas buffer chamber42 is provided at its lower portion with a reactiongas introducing opening45. Unlike thebuffer chamber17, the reactiongas buffer chamber42 does not have thegas supply chamber43 and theelectrode52. Opening areas of the reaction gas buffer chamber holes48 are increased from the upstream side toward the downstream side.
• The[0151]reaction tube6 is provided at its lower portion with theexhaust opening18. When different kinds of gases are alternately supplied to thewafers7 to form films by the ALD method, theexhaust opening18 can exhaust inside gas from thereaction tube6.
• FIG. 5A shows an outward appearance and the inside (shown with broken lines) of the[0152]reaction tube6 as viewed from a front surface of thebuffer chamber17.
• The[0153]buffer chamber17 is provided in thereaction tube6 such as to extend from its upper portion to lower portion. Thegas supply chamber43 is provided adjacent to thebuffer chamber17. Theelectrode52 covered with the electrode-protectingtube50 is disposed in thebuffer chamber17 from its upper portion to lower portion. Thegas supply chamber43 is provided at its lower portion with thegas introducing opening5.
• This electrode-protecting[0154]tube50 can be inserted into thebuffer chamber17 in a state in which the thin andlong electrode52 is isolated from atmosphere in thebuffer chamber17. Here, since the inside has the same atmosphere as outside air, theelectrode52 inserted into the electrode-protectingtube50 is oxidized by heat from the heater. Therefore, an inert gas purging mechanism is provided in the electro-deprotecting tube50 for charging or purging inert gas such as nitrogen to suppress the oxygen concentration to sufficiently low level.
• The reaction[0155]gas buffer chamber42 is provided in thereaction tube6 along its inner wall from its upper portion to lower portion away from thebuffer chamber17. The reactiongas buffer chamber42 is provided at its lower portion with the reactiongas introducing opening45.
• The[0156]reaction tube6 is provided at its lower portion with theexhaust opening18 along the inner wall of thereaction tube6 at a location opposed from the reactiongas buffer chamber42 with respect to thebuffer chamber17.
• FIG. 5B shows the inside of the[0157]reaction tube6 as viewed from front surfaces of the buffer chamber holes3 and the reaction gas buffer chamber holes48.
• In the[0158]reaction tube6, thebuffer chamber17 and thegas supply chamber43 adjacent to thebuffer chamber17 extend from the upper portion to the lower portion in thereaction tube6. The buffer chamber holes3 having the same pitches are provided at positions adjacent to the wafers (not shown) from the upper portion to the lower portion in thebuffer chamber17. The buffer chamber holes3 have the same opening areas in the wall of thebuffer chamber17 having the same thickness.
• The reaction[0159]gas buffer chamber42 is provided in thereaction tube6 along its inner wall from its upper portion to lower portion away from thebuffer chamber17. The reaction gas buffer chamber holes48 having the same pitches are provided adjacent to the wafers (not shown) from the upper portion to the lower portion in the reactiongas buffer chamber42. The opening areas of the reaction gas buffer chamber holes48 are increased from the upstream side toward the downstream side, from the lower portion to the upper portion in FIGS. 5A, 5B and5C.
• FIG. 5C is a vertical sectional view of the[0160]reaction tube6 as viewed from front surfaces of the gas supply chamber holes47 provided in thegas supply chamber43.
• The[0161]gas supply chamber43 is provided in thereaction tube6 from the upper portion to the lower portion adjacent to thebuffer chamber17. A partition wall between thebuffer chamber17 and thegas supply chamber43 is provided with the gas supply chamber holes47 from the upper portion to a location lower than the lower portion where the gas supply chamber holes47 are adjacent to the wafers (not shown). The reason why the gas supply chamber holes47 are opened up to the lowermost end of thebuffer chamber17 is that stagnation of gas is not generated in thebuffer chamber17.
• Like the gas nozzle holes provided in the gas nozzle explained in FIG. 3A, the opening areas of the gas supply chamber holes[0162]47 are increased from the upstream side toward the downstream side of the gas flow.
• Here, the film forming operation on the[0163]wafers7 in thereaction tube6 by the ALD method will be explained with reference to FIGS. 5A, 5B,5C and6.
• In this film forming example, active species of ammonia (NH[0164]₃) and dichlorsilane (SiH₂Cl₂) are alternately supplied as processing gas, and SiNx film (silicon nitride film) is formed by an atomic layer film-forming method.
• First, 100[0165]wafers7 are loaded into thereaction tube6, and the inside of thereaction tube6 is brought into the air-tight state and maintained in this state. Thereaction tube6 is exhausted by a pump (not shown) through an exhaust pipe, and a temperature in thereaction tube6 is constantly maintained in a range of 300 to 600° C. by adjusting the temperature using theheater16.
• The supply of ammonia to the[0166]gas supply chamber43 from thegas introducing opening5 is started.
• The opening areas of the gas supply chamber holes[0167]47 provided in thegas supply chamber43 are gradually increased from the upstream side toward the downstream side of the gas flow so that the flow rates of ammonia injected into thebuffer chamber17 from thegas supply chamber43 become the same.
• Therefore, the flow velocity of ammonia injected into the[0168]buffer chamber17 through the gas supply chamber holes47 is fast at the upstream side and slow at the downstream side, but the flow rates of the ammonia through all of the gas supply chamber holes47 are the same.
• The ammonia injected to the[0169]buffer chamber17 once stay therein, kinetic energies are exchanged, the flow velocities are equalized and the pressure in thebuffer chamber17 becomes uniform.
• In a state in which the ammonia is introduced into the[0170]buffer chamber17 and a pressure in the space between the pair of electrode-protecting tubes becomes uniform, high frequency electric power from the highfrequency power supply51 is supplied to the rod-like electrodes52 inserted into the two electrode-protectingtubes50 through theRF matching unit53,plasma14 is produced between the electro-deprotecting tubes50.
• By bringing the ammonia into plasma state in the[0171]buffer chamber17, active species of ammonia is produced. At that time, since the plasma is produced in a state in which the pressure in thebuffer chamber17 is uniform, an electron temperature and plasma concentration distribution which affect the production of active species also become uniform. Therefore, more uniform active species can be produced.
• The active species produced by the effect of plasma has lifetime, and if a distance between a plasma producing portion and the[0172]wafer7 is long, the species are deactivated before they are supplied to thewafers7, and an amount of active species which contribute to the reaction on thewafers7 is largely reduced. Therefore, it is preferable that the plasma is produced in the vicinity of thewafers7.
• According to this structure, since the active species of ammonia is produced in the[0173]buffer chamber17 which is in the vicinity of thewafers7, it is possible to efficiently supply a large amount of active species of produced ammonia to thewafers7.
• It is preferable that the distance between the two electrode-protecting[0174]tubes50 is set to an appropriate value so that a place where theplasma14 is generated is limited to inside thebuffer chamber17, and a preferable distance is about 20 mm. Theplasma14 may be produced anywhere inside thebuffer chamber17, and it is preferable that the gas introduced into thebuffer chamber17 passes through the plasma. Preferably, theplasma14 is produced between thebuffer chamber hole3 and the gassupply chamber hole47.
• A distance between the electrode-protecting[0175]tube50 and thebuffer chamber hole3 is adjusted to an appropriate value so that theplasma14 generated in thebuffer chamber17 is not dispersed and leaked outside thebuffer chamber17.
• As a result, only electrically neutral active species of ammonia are supplied from the buffer chamber holes[0176]3 to thewafers7, and it is possible to avoid the damage caused by charge-up of thewafer7.
• Since all the buffer chamber holes[0177]3 provided in thebuffer chamber17 have the same opening areas, the active species supplied to thewafers7 have uniform flow rates and flow velocities and thus, uniform film forming processing is carried out for thewafers7.
• Since the buffer chamber holes[0178]3 are located at intermediate portions of the gap between theadjacent wafers7 placed in the multistage manner, the processing gas is sufficiently supplied to thestacked wafers7.
• In the ALD method in which different kinds of processing gases are alternately supplied to form extremely thin films by one layer by one layer, if one layer of the extremely thin film including N atom is formed by supply of the active species of ammonia, the thickness is limited by appropriately setting a pressure or a temperature inside the[0179]reaction tube6, and the thickness of the film is not further increased.
• If the extremely thin film including the N atom is formed on the entire surface of the[0180]wafer7, the supply of RF electric power applied to theelectrode52 is cut off, and the supply of ammonia is stopped.
• Next, the inside of the[0181]reaction tube6 is purged by inert gas such as N₂or Ar and in this state, the gas is exhausted from theexhaust opening18. If the concentration of the active species of ammonia in thereaction tube6 has sufficiently reduced, the supply of the inert gas is stopped, and dichlorsilane is introduced into the reactiongas buffer chamber42 from the reactiongas introducing opening45.
• The reaction gas buffer chamber holes[0182]48 whose opening areas are gradually increased from the upstream side toward the downstream side of the reactiongas introducing opening45 are provided in the reactiongas buffer chamber42 toward the center of thereaction tube6. As a result, the dichlorsilane supplied to the wafers from the reaction gas buffer chamber holes48 has different flow velocities but has the same flow rates and is injected into thereaction tube6.
• If another set of[0183]gas supply chamber43 andbuffer chamber17 which is adjacent to thegas supply chamber43 which are same as those used for supplying ammonia are disposed in thereaction tube6 instead of the reactiongas buffer chamber42, and dichlorsilane is supplied from the buffer chamber holes3, it is preferable because the flow rater and flow velocities become uniform.
• In this embodiment, if the flow rates of dichlorsilane is equalized using the reaction[0184]gas buffer chamber42 which is more simple than the combination of thegas supply chamber43 and thebuffer chamber17, it is possible to form sufficiently uniform films on thewafers7.
• If particles including Si is adsorbed on the[0185]wafer7 in the extremely thin film form, the supply of the dichlorsilane is stopped. Then, the inside of thereaction tube6 is purged by inert gas such as N₂or Ar, the gas is exhausted from theexhaust opening18 and when the concentration of dichlorsilane in thereaction tube6 is reduced sufficiently, the supply of the inert gas is stopped.
• A SiNx film of about 1 Å is formed through this series of process. When a SiNx film of 500 Å is to be formed on a[0186]wafer7, the above process is repeated about 500 times.
• If the boat (not shown) in which the[0187]wafers7 are placed is rotated at a constant speed, even if gas is supplied from a side of thewafers7, more uniform film forming processing is realized over the entire surfaces of thewafers7. In this embodiment, the rotating speed of 1 to 10 rpm is sufficient.
• When the boat was not rotated, uniformity of film thickness of the[0188]wafer7 is about ±5%, but when the boat was rotated, the uniformity was <±1%.
• (Third to Fifth Embodiments)[0189]
• Different Embodiments Using ALD Method for Film Forming[0190]
• FIG. 7 is a lateral sectional view of a reaction tube of a vertical type substrate processing apparatus according to a third embodiment of the present invention.[0191]
• The[0192]reaction tube6 shown in FIG. 7 has the same structure as that shown in FIG. 6. In FIG. 6, the electrode for producing plasma is disposed in thebuffer chamber17. In FIG. 7, anultraviolet lamp54 for activating gas and areflection plate58 for preventing ultraviolet from radiating out from thebuffer chamber17 are provided in combination.
• Reaction gas is activated by light energy of the[0193]lamp54.
• The processing gas which is brought into the active species in the[0194]buffer chamber17 having the above structure is injected toward thewafers7 from the buffer chamber holes3, and films are formed on thewafers7 by the ALD method.
• FIG. 8 is a lateral sectional view of a reaction tube of a vertical type substrate processing apparatus according to a fourth embodiment of the invention.[0195]
• The[0196]reaction tube6 shown in FIG. 8 has the same structure as that shown in FIG. 7. In FIG. 7, the reaction gas is activated by light energy. In the fourth embodiment, an exotherm (hot wire, hereinafter)55 having appropriate electrical resistance value is heated by apower supply57 to a temperature of 1,600° C. or higher, and gas which comes into contact with the hot wire is activated.
• As the[0197]hot wire55 having the appropriate electrical resistance value and generating the active species, a W (tungsten) wire having about 0.5 mm or the like can be suitably used.
• This[0198]hot wire55 is heated to 1,600° C. or higher by electric power of thepower supply57, and processing gas which comes into contact with thehot wire55 is activated by the thermal energy.
• The processing gas which is brought into the active species in the[0199]buffer chamber17 having the above structure is injected toward thewafers7 from the buffer chamber holes3, and films are formed on thewafers7 by the ALD method.
• FIG. 9 is a lateral sectional view of a reaction tube of a vertical type substrate processing apparatus according to a fifth embodiment of the invention.[0200]
• The[0201]reaction tube6 shown in FIG. 9 has the same structure as that shown in FIG. 6. In FIG. 6, the plasma generating electrode is disposed in thebuffer chamber17. In the fifth embodiment shown in FIG. 9, aremote plasma unit56 is disposed on a gas passage upstream from thegas introducing opening5 through which processing gas is introduced into thereaction tube6, and gas passing through theremote plasma unit56 is allow to produce plasma.
• The processing gas passing through the[0202]remote plasma unit56 is reacted with plasma and brought into active species, the gas which was brought into the active species enters thereaction tube6 from thegas introducing opening5, and is supplied to thebuffer chamber17 through thegas supply chamber43, and is further supplied to thewafers7 as uniform gas from the buffer chamber holes3 provided in thebuffer chamber17. Then, films are formed on thewafers7 by the ALD method.
• An ICP coil or the like is suitably used as the[0203]remote plasma unit56.
• According to this structure, an amount of active species to be supplied to the wafers is reduced and processing efficiency is deteriorated as compared with the apparatus shown in FIG. 6. This fifth embodiment is used for a case in which the deterioration in the processing efficiency makes no problem.[0204]
• (Sixth to Eighth Embodiments)[0205]
• Sixth to eighth embodiments of the present invention will be explained with reference to FIGS. 10, 11 and[0206]12. FIGS. 10, 11 and12 are lateral sectional views of left halves ofreaction tubes6 used for substrate processing apparatuses of the sixth, seventh and eighth embodiments of the invention, respectively.
• In the sixth, seventh and eighth embodiments shown in FIGS. 10, 11 and[0207]12, respectively, agas nozzle102 is disposed in thebuffer chamber17 from the lower portion to the upper portion of thereaction tube6 in the stacking direction of thewafers7. Thegas introducing opening5 is in communication with a lower portion of thegas nozzle102. A large number of gas nozzle holes (not shown) are provided in thegas nozzle102 in the vertical direction. Like the first to fifth embodiments, the exhaust opening which is in communication with an exhaust pump (not shown) is formed in a side surface of a lower portion of thereaction tube6.
• In the sixth embodiment shown in FIG. 10, a[0208]wall172 which is a portion of thebuffer chamber17 is a portion of a wall of thereaction tube6. Two electrode-protectingtubes50 are disposed closer to awall surface173 of a portion of awall171 of thebuffer chamber17 provided with the buffer chamber holes3 than awall surface174 of thewall172. Twoelectrodes52 protected by the two electrode-protectingtubes50 are also disposed closer to thewall surface173 of thewall171 than thewall surface174 of thewall172. The two electrode-protectingtubes50 are located in the vicinity of thewall171 of thebuffer chamber17 provided with the buffer chamber holes3 (preferably, a distance between the electrode-protectingtubes50 and the wall surface of thewall171 of thebuffer chamber17 is 0 to 5 mm. Here, 0 mm means a case in which the electrode-protectingtubes50 are tightly connected to the wall surface). The twoelectrodes52 and the two electrode-protectingtubes50 are disposed astride the buffer chamber holes3 (that is, the buffer chamber holes3 are located between the two electrode-protecting tubes50). With this arrangement, a distance between theplasma14 and thebuffer chamber hole3 can be shortest.
• If the two electrode-protecting[0209]tubes50 are brought close to thewall surface173 of thewall171 constituting thebuffer chamber17, it is possible to limit a main gas flow path. If the buffer chamber holes3 are provided at location where the limited main gas flow path passes between the two electrode-protectingtubes50, the reaction gas can efficiently pass through a region where the concentration of theplasma14 is high, and it is possible to increase the concentration of the active species.
• In the case of FIG. 10, the reaction gas path in the[0210]buffer chamber17 can roughly be divided into paths D, E, e and f. The paths D and E are main gas flow path, and most of reaction gas passes between the two electrode-protectingtubes50, i.e., passes through the region where the concentration of theplasma14 is high.
• Since the[0211]plasma14 and the buffer chamber holes3 are located very close to each other, and unnecessary swelling portion becomes minimum. Therefore, deactivation of active species generated in the paths D and E can be suppressed as low as possible. Even if the active species are deactivated before the active species enter the buffer chamber holes3, the active species can be activated again by theplasma14.
• The paths e and f which do not pass between the two electrode-protecting[0212]tubes50 also pass near theplasma14 just in front of the buffer chamber holes3. Therefore, the concentration of the active species is increased, and deactivation of active species until the active species are introduced into thereaction tube6 is small like the paths C and D.
• That is, according to this embodiment, the following points become possible.[0213]
• 1) The active species can be activated with plasma having high concentration (concentration of the active species is increased at the time of excitation)[0214]
• 2) A substrate to be processed (wafer) can be carried without deactivating the active species.[0215]
• This embodiment also has a feature that it is unnecessary to control the gas flow paths before the gas is brought into active species so that concentration of the active species is not different in the paths D and E.[0216]
• If the electrode-protecting[0217]tubes50 and thebuffer chamber17 are brought into tight contact with each other, since the paths e and f are cut off, and the gas paths can be limited to the paths D and E. This is effective because the active species having high concentration are supplied to a substrate. There is no clearance for the paths e and f. This is preferable because there is no variation in concentration of reaction gas active species between apparatuses.
• FIG. 11 shows the seventh Embodiment. In this embodiment, the[0218]gas nozzle102 and the buffer chamber holes3 are disposed between the two electrode-protectingtubes50 so that gas supplied from thegas nozzle102 straightly pass through (path F), theplasma14 and the buffer chamber holes3. In this structure, the concentration of the active species can be increased like the structure shown in FIG. 10.
• FIG. 12 shows the eighth embodiment. In this embodiment, one of the two electrode-protecting[0219]tubes50 is brought close to thewall surface173 of thewall171 provided with the buffer chamber holes3, and the other electrode-protectingtube50 is brought close to thewall surface174 of the portion of thewall172 of thebuffer chamber17 which is the portion of the wall of thereaction tube6, so that the main gas flow path is limited. The The buffer chamber holes3 are provided at locations where the main gas flow path I passes between the two electrode-protectingtubes50.
• If this embodiment shown in FIG. 12 is compared with the embodiments shown in FIGS. 10 and 11, a distance between the[0220]plasma14 and thebuffer chamber hole3 becomes long and correspondingly, a swelling portion is generated, but the deactivation can be reduced by bringing one of the electrode-protectingtubes50 closer to thewall surface173 of thewall171 constituting thebuffer chamber17.
• As described above, the concentration of the active species of the reaction gas can be increased by optimizing the layout of the[0221]buffer chamber17, the electrode-protectingtubes50 and the buffer chamber holes3.
• The concentration of the active species of the reaction gas can be enhanced by optimizing the relative position of the[0222]buffer chamber17, the electrode-protectingtubes50 and the buffer chamber holes3 as described above. When the processing uniformity between apparatuses, the reliability and repeatability are taken into consideration, it is preferable that there is no variation in the relative position.
• In the above example, since the electrode-protecting[0223]tubes50, thebuffer chamber17 and the buffer chamber holes3 are independent from one another, an assembling error is generated and thus, it is considered that the concentration of the active species of the reaction gas is varied between the apparatuses.
• Therefore, if a reaction tube in which the[0224]reaction tube6, a wall constituting thebuffer chamber17, the buffer chamber holes3 and the electrode-protectingtubes50 are integrally formed is used, it is possible to suppress the variation. There is no problem if these elements are made of quartz and integrally welded to each other.
• In the above example, the positions of the electrode-protecting[0225]tubes50 are explained because the electrode-protectingtubes50 are used, but when the electrode-protectingtubes50 are not used, theelectrodes52 should be located at same positions of the electro-deprotecting tubes50.
• If the structures shown in the sixth to eighth embodiments are used, the apparatus can be used as the CVD apparatus like the first embodiment, and if a[0226]buffer chamber42 is added in addition to thebuffer chamber17 as shown in FIG. 6, the apparatus can be used as the ALD apparatus.
• (Ninth Embodiment)[0227]
• A ninth embodiment of the invention will be explained with reference to FIG. 13. In this embodiment, the[0228]buffer chamber42 shown in FIG. 6 is added to the apparatus of the sixth embodiment shown in FIG. 10, and the apparatus is formed into the ALD apparatus.
• The[0229]gas nozzle102 is provided with a large number ofgas nozzle hole103 in the vertical direction. The gas nozzle holes103 is provided toward awall surface176 of awall175 of thebuffer chamber17. If gas nozzle holes103 are provided toward the inside of thebuffer chamber17 which is on the other side from thewall surface176, when silicon nitride films are to be formed using the ALD method by alternately supplying ammonia from thegas nozzle102 and dichlorsilane from thebuffer chamber42 like the second embodiment, and when ammonia stays and dichlorsilane flows, reaction byproduct is generated, which becomes a cause of particles. Therefore, the gas nozzle holes103 are directed toward thewall surface176 of thewall175 of thebuffer chamber17, and after ammonia is supplied, the chamber is purged with inert gas for not allowing ammonia to stay and for preventing particles from being generated.
• In the sixth to eighth embodiments, the[0230]gas nozzle102 is provided at its side surface with the large number of gas nozzle holes (not shown) in the vertical direction. In the ninth embodiment, thegas nozzle102 is provided at its side surface with the large number of gas nozzle holes103. Thegas nozzle102 may have a predetermined length, and the gas nozzle holes may be opened at the upper portion of thegas nozzle102. In this case, it is preferable that a height of thegas nozzle102 is lower than the loading position of thewafer7.
• The entire disclosures of Japanese Patent Application No. 2002-104011 filed on Apr. 5, 2002 and Japanese Patent Application No. 2002-203397 filed on Jul. 12, 2002 including specifications, claims, drawings and abstracts are incorporated herein by reference in their entireties.[0231]
• Although various exemplary embodiments have been shown and described, the invention is not limited to the embodiments shown. Therefore, the scope of the invention is intended to be limited solely by the scope of the claims that follow.[0232]

Claims (20)

What is claimed is:

1. A substrate processing apparatus, comprising;

a reaction chamber which is to accommodate stacked substrates,

a gas introducing portion, and

a buffer chamber, wherein

said gas introducing portion is provided along a stacking direction of said substrates, and introduces substrate processing gas into said buffer chamber,

said buffer chamber includes a plurality of gas-supply openings provided along the stacking direction of said substrates, and said processing gas introduced from said gas introducing portion is supplied from said gas-supply openings to said reaction chamber.

2. A substrate processing apparatus as recited inclaim 1, wherein

opening areas of said gas-supply openings provided in said buffer chamber are substantially equal to each other.

3. A substrate processing apparatus as recited inclaim 1, wherein

said gas introducing portion is provided with a plurality of gas introducing openings along the stacking directions of said substrates.

4. A substrate processing apparatus as recited inclaim 1, wherein

said gas introducing portion includes a gas-supply tube provided in said buffer chamber, and said gas-supply tube is provided with a plurality of gas introducing openings along the stacking direction of said substrates.

5. A substrate processing apparatus as recited inclaim 3, wherein

opening areas of said gas introducing openings of said gas introducing portion are increased from an upstream side toward a downstream side.

6. A substrate processing apparatus as recited inclaim 1, wherein

said gas-supply openings of said buffer chamber are disposed with the same pitch as that of the stacked substrates.

7. A substrate processing apparatus as recited inclaim 1, further comprising another buffer chamber.

8. A substrate processing apparatus as recited in claim1, wherein

said gas-supply openings of said buffer chamber are provided lower than a position where said substrates are disposed.

9. A substrate processing apparatus as recited inclaim 1, wherein

said buffer chamber is provided therein with a gas activating member for activating said substrate processing gas.

10. A substrate processing apparatus as recited inclaim 9, wherein

said gas activating member is electrodes for generating plasma.

11. A substrate processing apparatus as recited inclaim 10, wherein

each of said electrodes is provided with a protecting member, atmosphere in said buffer chamber and said electrodes are not in contact with each other.

12. A substrate processing apparatus as recited inclaim 11, wherein

inert gas is charged into said protecting member, or said protecting member is purged with inert gas.

13. A substrate processing apparatus as recited inclaim 10, wherein

said gas-supply openings of said buffer chamber are provided between said electrodes.

14. A substrate processing apparatus as recited inclaim 1, wherein

said buffer chamber is provided in said reaction chamber,

said buffer chamber includes first and second wall surfaces,

said gas-supply openings are provided in said first wall surface of said buffer chamber,

said second wall surface of said buffer chamber is a portion of a wall surface of said reaction chamber,

said buffer chamber is provided therein with electrodes for generating plasma, and

at least one of said electrode is brought closer to said first wall surface than said second wall surface.

15. A substrate processing apparatus as recited in claim1, wherein

said buffer chamber is provided in said reaction chamber,

said buffer chamber includes first and second wall surfaces,

said gas-supply openings are provided in said first wall surface of said buffer chamber,

said second wall surface of said buffer chamber is a portion of a wall surface of said reaction chamber,

said buffer chamber is provided therein with electrodes for generating plasma,

each of said electrodes is provided with a protecting member, atmosphere in said buffer chamber and said electrodes are not in contact with each other, and

at least one of said electrode is brought closer to said first wall surface than said second wall surface.

16. A substrate processing apparatus as recited inclaim 1, wherein

said apparatus further comprising a remote plasma unit connected to said gas introducing portion,

said substrate processing gas activated by said remote plasma unit is introduced into said buffer chamber from said gas introducing portion.

17. A substrate processing apparatus, comprising:

a reaction chamber which is to accommodate stacked substrates,

a plurality of buffer chambers, and

a plurality of gas introducing portions for respectively introducing substrate processing gases to said buffer chambers, wherein

said buffer chambers respectively include a plurality of gas-supply openings provided in a stacking direction of said substrates, and said substrate processing gas introduced from each of said gas introducing portions is supplied to said reaction chamber from said gas-supply openings of each of said buffer chambers.

18. A reaction container, comprising:

a reaction chamber which is to accommodate stacked substrates,

a plurality of buffer chambers, and

a plurality of gas introducing portions for respectively introducing substrate processing gases to said buffer chambers, wherein

said buffer chambers respectively include a plurality of gas-supply openings provided in a stacking direction of said substrates, and said substrate processing gas introduced from each of said gas introducing portions is supplied to said reaction chamber from said gas-supply openings of each of said buffer chambers.

19. A reaction container as recited inclaim 18, wherein

at least one of said gas introducing portions is provided along a stacking direction of said substrates.

20. A reaction container, comprising:

a reaction chamber which is to accommodate stacked substrates,

a gas introducing portion, and

a buffer chamber, wherein

said gas introducing portion is provided along a stacking direction of said substrates, and introduces substrate processing gas into said buffer chamber,

said buffer chamber includes a plurality of gas-supply openings provided along the stacking direction of said substrates, and said processing gas introduced from said gas introducing portion is supplied from said gas-supply openings to said reaction chamber.

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