Substrate processing apparatus, substrate processing method, and semiconductor device manufacturing method

Abstract

The present invention comprises: (a) a processing tube including a cylinder portion which has a covered top and which internally accommodates a substrate; (b) a supply buffer which is provided on a side wall of the cylinder portion and which protrudes outward from the side wall; (c) a first injection device which is installed inside the supply buffer and which extends along the direction of an axis of the cylinder portion; and (d) a plurality of exhaust sections which are formed in the side walls of the cylinder portion and which exhaust raw material gas, the plurality of exhaust sections including a pair of exhaust sections opening from both sides of a virtual plane set to pass through the circumferential center of the cylinder portion and the axis of the cylinder portion at a boundary between the supply buffer and the cylinder portion in a plan view.

Description

[Technical Field]

[0001] The present disclosure relates to a substrate processing apparatus, a substrate processing method, and a method for manufacturing a semiconductor device. [Background technology]

[0002] Conventionally, as an example of a substrate processing apparatus, a semiconductor manufacturing apparatus for manufacturing semiconductor devices has been known. As an example of a semiconductor manufacturing apparatus, Japanese Patent Publication No. 2019-203182, Japanese Patent Publication No. 2022-52622, and Korean Patent Publication No. 101464644 disclose vertical semiconductor manufacturing apparatuses that process multiple substrates while holding them in multiple stages in the vertical direction. In the vertical semiconductor manufacturing apparatus, a film formation process that forms a predetermined film on the surface of the substrate can be performed as the substrate processing.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2019-203182 Patent Document 2: Japanese Patent Application Laid-Open No. 2022-52622 Patent Document 3: Korean Patent Publication No. 101464644 Summary of the Invention [Problem to be solved by the invention]

[0004] During a film formation process, when source gases are sprayed onto a substrate in a processing chamber, uneven flow of the source gas on the substrate surface can cause uneven concentrations of the source gases or intermediates. If uneven concentrations of these gases occur on the substrate surface, the in-plane uniformity of the gas adsorbed on the substrate surface can decrease, and step coverage can also decrease.

[0005] The present disclosure provides a technique that can improve the uniformity of the flow of source gas on the surface of a substrate. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, (a) a process tube having a cylindrical portion whose upper portion is covered and which accommodates a substrate therein; (b) a supply buffer provided on a side wall of the cylindrical portion and protruding outward from the side wall; (c) a first injection device provided inside the supply buffer and extending along the axis of the cylindrical portion; (d) A configuration is provided which includes a plurality of exhaust sections formed on the side wall of the cylindrical section and which exhaust the raw material gas, the plurality of exhaust sections having a pair of exhaust sections which open on both sides of an imaginary plane which is set to pass through the circumferential center of the cylindrical section and the axis of the cylindrical section at the boundary between the supply buffer and the cylindrical section in a plan view. [Effects of the Invention]

[0007] According to the present disclosure, the uniformity of the flow of the source gas on the surface of the substrate can be improved. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a front view illustrating a substrate processing apparatus according to an embodiment of the present disclosure, with a portion cut along a vertical plane extending in the depth direction. [Figure 2] FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1, illustrating the substrate processing apparatus according to this embodiment by cutting it in the horizontal direction. [Figure 3] FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2, illustrating the processing vessel of the substrate processing apparatus according to this embodiment, cut along a vertical plane extending in the width direction. [Figure 4] FIG. 4 is a side view illustrating a main exhaust slit and a sub-exhaust slit formed in an inner pipe of a processing vessel of a substrate processing apparatus according to this embodiment, viewed from the outer pipe side. [Figure 5] FIG. 5 is a cross-sectional view illustrating a first injector that injects a source gas in the substrate processing apparatus according to this embodiment, cut in the horizontal direction. [Figure 6] FIG. 6 is a block diagram illustrating a control system of a control unit of the substrate processing apparatus according to this embodiment. [Figure 7] FIG. 7 is a flowchart illustrating a substrate processing process according to this embodiment. [Figure 8]FIG. 8 is a diagram illustrating, using a simulation model, the distribution of source gas concentration inside the cylindrical portion when the center-to-center distance between the two first injectors of the substrate processing apparatus according to this embodiment is 22 mm. [Figure 9] FIG. 9 is a graph illustrating the results of a simulation analyzing the relationship between the uniformity of the source gas concentration and the center-to-center distance between the two first injectors. [Figure 10A] FIG. 10A is a diagram illustrating the flow and partial pressure distribution of the raw material gas inside the cylindrical portion in the substrate processing apparatus according to this embodiment when the first injection device has a single row of ejection holes and a pair of secondary exhaust slits is not provided. [Figure 10B] FIG. 10B is a diagram illustrating the flow and partial pressure distribution of the raw material gas inside the cylindrical portion in the substrate processing apparatus according to this embodiment when the first injection device has three rows of ejection holes and a pair of secondary exhaust slits is not provided. [Figure 10C] FIG. 10C is a diagram illustrating the flow and partial pressure distribution of the raw material gas inside the cylindrical portion when the first injection device has three rows of ejection holes and a pair of auxiliary exhaust slits in a substrate processing apparatus according to a seventh modified example of this embodiment. [Figure 11] FIG. 11 is a diagram illustrating the generation state of a return flow inside the cylindrical portion of the substrate processing apparatus according to this embodiment, with different conditions depending on the shape of the first injector and the flow rate of the source gas. [Figure 12A] FIG. 12A is a diagram illustrating a substrate processing apparatus according to a first modified example, in which six first ejection devices are provided. [Figure 12B] FIG. 12B is a diagram illustrating a substrate processing apparatus according to a second modified example, in which a plurality of first ejection devices are arranged away from the substrate. [Figure 12C] FIG. 12C is a diagram illustrating a substrate processing apparatus according to a third modified example, in which a sidewall having a slit is provided between the first jetting device and the substrate, and the jetting holes of the multiple first jetting devices open toward the sidewall on the opposite side from the substrate. [Figure 12D]FIG. 12D is a diagram illustrating a substrate processing apparatus according to a fourth modified example, in which a sidewall having a slit is provided between the first jetting device and the substrate, and the jetting holes of the multiple first jetting devices open toward the sidewall having the slit. [Figure 12E] FIG. 12E is a diagram illustrating a substrate processing apparatus according to a fifth modified example, in which a plurality of first jetting devices are positioned away from the substrate, a sidewall having slits is provided between the first jetting devices and the substrate, and the jetting holes of the plurality of first jetting devices open toward the sidewall having slits. [Figure 13] FIG. 13 is a perspective view illustrating a substrate processing apparatus according to a sixth modified example in which fins are provided on each of the main exhaust slit and the sub-exhaust slit. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, one embodiment of the present disclosure will be described mainly with reference to Figures 1 to 13. Note that all drawings used in the following description are schematic, and the dimensional relationships between elements, the ratios of elements, etc. shown in the drawings do not necessarily match those in reality. Furthermore, the dimensional relationships between elements, the ratios of elements, etc. do not necessarily match between multiple drawings.

[0010] Furthermore, unless otherwise specified in the specification, each element is not limited to one, and may be present in plural. Furthermore, in the drawings, substantially identical elements are denoted by the same reference numerals, and redundant explanations in the specification will be omitted.

[0011] <Overall configuration of substrate processing equipment> First, the overall configuration of a substrate processing apparatus 10 according to this embodiment will be described with reference to Figures 1 to 6. Note that the up-down direction H of the apparatus indicates the vertical direction, the width direction W of the apparatus indicates the horizontal direction, and the depth direction D of the apparatus indicates the horizontal direction.

[0012] 1, the substrate processing apparatus 10 includes a control unit 280 that controls each unit and a processing furnace 202. The processing furnace 202 has a heater 207 as a heating means. The heater 207 is cylindrical and is installed in the vertical direction of the apparatus by being supported on a heater base (not shown). The heater 207 also functions as an activation mechanism that activates the processing gas by heat. The control unit 280 will be described in detail later.

[0013] A reaction tube 203 serving as a processing tube constituting a reaction vessel is arranged upright inside the heater 207 and concentrically with the heater 207. The reaction tube 203 corresponds to the processing vessel of the present disclosure. The reaction tube 203 is made of a heat-resistant material such as quartz (SiO2) or silicon carbide (SiC). The substrate processing apparatus 10 is a so-called hot-wall type.

[0014] As shown in Fig. 2, the reaction tube 203 has a cylindrical inner tube 12 and a cylindrical outer tube 14 provided to surround the inner tube 12. That is, the outer tube 14 constitutes the reaction tube 203 together with the inner tube 12. The outer tube 14 surrounds the inner tube 12, thereby forming a gap as an exhaust space S between the outer tube 14 and the cylindrical portion. The inner tube 12 is disposed concentrically with the outer tube 14. The inner tube 12 is an example of a tubular member.

[0015] The inner tube 12 has a covered upper portion and a cylindrical sidewall for accommodating a plurality of substrates therein. Specifically, as shown in Fig. 1, the inner tube 12 is formed in a ceiling-like shape with an open lower end and a closed upper end with a flat wall. The outer tube 14 is also formed in a ceiling-like shape with an open lower end and a closed upper end with a flat wall.

[0016] 2, a supply buffer 222 serving as a nozzle chamber is formed in the exhaust space S formed between the inner pipe 12 and the outer pipe 14. That is, the supply buffer 222 is a supply space in which a nozzle for supplying a processing gas is disposed. The supply buffer 222 will be described in detail later.

[0017] 1, a processing chamber 201 for processing wafers 200 as substrates is formed inside the inner tube 12. The processing chamber 201 can accommodate a boat 217, which is an example of a substrate holder capable of holding the wafers 200 in a horizontal position and aligned vertically in multiple stages, and the inner tube 12 surrounds the accommodated wafers 200. The multiple wafers 200 are arranged inside the cylindrical portion of the inner tube 12 along the axial direction of the cylindrical portion. Details of the inner tube 12 will be described later.

[0018] The lower end of the reaction tube 203 is supported by a cylindrical manifold 226. The manifold 226 is made of a metal such as a nickel alloy or stainless steel, or a heat-resistant material such as SiO2 or SiC. A flange is formed at the upper end of the manifold 226, and the lower end of the outer tube 14 is placed on this flange. An airtight member 220 such as an O-ring is disposed between this flange and the lower end of the outer tube 14, making the inside of the reaction tube 203 airtight.

[0019] A seal cap 219 is airtightly attached to the opening at the lower end of the manifold 226 via an airtight member 220 such as an O-ring, and the opening side at the lower end of the reaction tube 203, i.e., the opening of the manifold 226, is airtightly closed. The seal cap 219 is made of a metal such as a nickel alloy or stainless steel, and is formed in a disk shape. The seal cap 219 may be configured so that its exterior is covered with a heat-resistant material such as SiO2 or SiC.

[0020] A boat support stand 218 that supports the boat 217 is provided on the seal cap 219. The boat support stand 218 is made of a heat-resistant material such as SiO2 or SiC, and functions as a heat insulating portion.

[0021] The boat 217 is erected on a boat support stand 218. The boat 217 is made of a heat-resistant material such as SiO2 or SiC. As shown in Fig. 2, the boat 217 has a bottom plate (not shown) fixed to the boat support stand 218 and a top plate disposed above the bottom plate, and a plurality of support columns 217a are installed between the bottom plate and the top plate.

[0022] The boat 217 holds a plurality of wafers 200 to be processed in the processing chamber 201 in the inner tube 12. As shown in Fig. 2, the plurality of wafers 200 are supported by supports 217a of the boat 217 with the wafers 200 held horizontally at a fixed interval from one another and with their centers aligned. The loading direction of the plurality of wafers 200 is the axial direction of the reaction tube 203. In other words, the centers of the substrates are aligned with the central axis of the boat 217, and the central axis of the boat 217 coincides with the central axis of the reaction tube 203.

[0023] A rotation mechanism 267 for rotating the boat is provided below the seal cap 219. A rotation shaft 265 of the rotation mechanism 267 passes through the seal cap 219 and is connected to the boat support base 218. The rotation mechanism 267 rotates the boat 217 via the boat support base 218, thereby rotating the wafers 200.

[0024] The seal cap 219 is vertically raised and lowered by an elevator 115 as a lifting mechanism provided outside the reaction tube 203 , and the boat 217 can be carried in and out of the processing chamber 201 .

[0025] The manifold 226 is provided with a plurality of nozzle supports that support the gas nozzle 342a, return nozzle 340, return nozzle 341, and gas nozzle 342c that supply gas to the inside of the processing chamber 201, and the nozzle supports penetrate the manifold 226. In this embodiment, four nozzle supports are provided. In FIG. 1, the return nozzle 341 and nozzle support 350c are illustrated as examples. The nozzle supports are made of a material such as a nickel alloy or stainless steel.

[0026] Gas supply pipes 310a to 310d that supply gas into the processing chamber 201 are connected to one end of the nozzle support. Gas nozzle 342a, return nozzle 340, return nozzle 341, and gas nozzle 342c are connected to the other end of the nozzle support. Gas nozzles 342a and 342c are made of a heat-resistant material such as SiO2 or SiC. Details of gas nozzles 342a and 342c will be described later.

[0027] (gas supply pipe) Gas supply pipe 310a communicates with corresponding gas nozzle 342a via a nozzle support (not shown). Gas supply pipe 310d communicates with corresponding gas nozzle 342c via a nozzle support (not shown). Gas supply pipe 310b communicates with return nozzle 340 via a nozzle support (not shown). Gas supply pipe 310c communicates with return nozzle 341 via nozzle support 350c (not shown).

[0028] The gas supply pipe 310a is provided with, in order from the upstream side in the gas flow direction, a gas supply source 360a for supplying an assist gas as a processing gas, a mass flow controller (MFC) 320a which is an example of a flow rate controller, and a valve 330a which is an on-off valve. The gas supply pipe 310b is provided with, in order from the upstream side, a gas supply source 360b for supplying a raw material gas as a processing gas, an MFC 320b, a tank 322b, and a valve 330b.

[0029] The gas supply pipe 310c is provided with, in order from upstream, a gas supply source 360c for supplying a raw material gas as a processing gas, an MFC 320c, a tank 322c, and a valve 330c. The gas supply pipe 310d is provided with, in order from upstream, a gas supply source 360d for supplying a reactive gas as a processing gas, an MFC 320d, and a valve 330d.

[0030] A reactive gas is supplied from the gas supply pipe 310d. A source gas is supplied from the gas supply pipes 310b and 310c. Although not shown, each gas nozzle in this embodiment is also provided with a gas supply pipe for supplying nitrogen (N2) gas or the like as a purge or assist gas, along with an MFC and a valve.

[0031] A plurality of exhaust slits, including a main exhaust slit 236 and sub-exhaust slits 238, are formed on the side wall of the inner pipe 12. The plurality of exhaust slits exhaust gas inside the inner pipe 12 to the exhaust space S. The main exhaust slit 236 in this embodiment corresponds to the exhaust section and the main exhaust section of the present disclosure. The sub-exhaust slit 238 in this embodiment corresponds to the exhaust section and the sub-exhaust section of the present disclosure. In this embodiment, the number of the plurality of exhaust slits is three, consisting of one main exhaust slit 236 and two sub-exhaust slits 238. In this disclosure, the number of the plurality of exhaust slits may be at least two or more.

[0032] The lower exhaust port 237 is an auxiliary opening provided in the inner pipe below the main exhaust slit 236, and exhausts gas near the boat support base 218. Note that the lower exhaust port 237 is not essential.

[0033] An exhaust port 230 serving as an exhaust port is formed in the outer tube 14 of the reaction tube 203. The exhaust port 230 is formed below the lower end of the main exhaust slit 236, and connects the exhaust space S to the outside of the reaction tube 203. As shown in Fig. 2, the exhaust port 230 is disposed on the opposite side of the supply buffer 222, and in a plan view, the supply buffer 222, the exhaust port 230, and the main exhaust slit 236 (described later) are arranged to be aligned on a straight line passing through the center of the substrate.

[0034] The exhaust unit may be, for example, an exhaust port having an opening that connects the inside of the processing chamber 201 to the exhaust space S and indirectly exhausts gas inside the processing chamber 201 to the outside via the exhaust space S, or an opening that is directly connected to an exhaust duct, which will be described later. The latter embodiment will be described later as a seventh modified example. The exhaust duct 231 is a conduit that extends outward from the exhaust port 230 and guides the exhaust from the reaction tube 203 to a vacuum pump 246, which serves as a vacuum exhaust device.

[0035] The exhaust duct 231 is provided with a pressure sensor 245 that detects the pressure inside the processing chamber 201, and an APC (Auto Pressure Controller) valve 244 as a pressure regulator. The downstream side of the vacuum pump 246 is connected to a waste gas treatment device (not shown). Thus, by controlling the output of the vacuum pump 246 and the aperture of the APC valve 244, the processing chamber 201 can be evacuated to a predetermined pressure (vacuum level).

[0036] In addition, a temperature sensor (not shown) serving as a temperature detector is installed inside or on the outer wall of the reaction tube 203, and the power supplied to the heater 207 is adjusted based on the temperature information detected by the temperature sensor, so that the temperature inside the processing chamber 201 has a desired temperature distribution.

[0037] In this specification, the processing temperature refers to the temperature of the wafer 200 or the temperature inside the processing chamber 201, and the processing pressure refers to the pressure inside the processing chamber 201. Furthermore, the processing time refers to the time the processing continues. These terms also apply to the following explanations.

[0038] In the processing furnace 202, a boat 217 carrying multiple wafers 200 to be batch processed in multiple stages is loaded into the processing chamber 201 by a boat support 218. The wafers 200 loaded into the processing chamber 201 are then heated to a predetermined temperature by a heater 207. An apparatus having such a processing furnace is called a vertical batch apparatus.

[0039] <Main part configuration> Next, a detailed description will be given of the supply buffer 222, the return nozzles 340 and 341 as first injectors, and the exhaust slits including the main exhaust slit 236 and the sub-exhaust slit 238 in the substrate processing apparatus 10 according to this embodiment. Note that the first injector is not limited to a tubular member such as a nozzle, as long as it is capable of injecting the source gas into the processing chamber 201.

[0040] (supply buffer) 2, the supply buffer 222 is provided on the side wall of the cylindrical portion of the inner pipe 12 and is a region that protrudes outward from the side wall. The supply buffer 222 is formed in the exhaust space S between the outer peripheral surface 12c of the inner pipe 12 and the inner peripheral surface 14a of the outer pipe 14. The supply buffer 222 is divided into three portions along the circumferential direction of the cylindrical portion by the third partition 18c and the fourth partition 18d.

[0041] The supply buffer 222 is formed between the first partition 18a and the second partition 18b, and between the inner pipe 12 and the arc-shaped top plate 20 that connects the tip of the first partition 18a and the tip of the second partition 18b. Both the first partition 18a and the second partition 18b extend from the outer peripheral surface 12c of the inner pipe 12 toward the outer pipe 14. Both the first partition 18a and the second partition 18b are continuous with the inner pipe 12.

[0042] A third partition 18c and a fourth partition 18d are formed inside the supply buffer 222, extending from the outer peripheral surface 12c of the inner tube 12 toward the top plate 20. Both the third partition 18c and the fourth partition 18d extend toward the top plate 20 in parallel with the first partition 18a and the second partition 18b. The third partition 18c and the fourth partition 18d are lined up in this order from the first partition 18a side toward the second partition 18b side.

[0043] The top plate 20 is spaced apart from the outer tube 14. The tip of the third partition 18c opposite the wafer 200 and the tip of the fourth partition 18d opposite the wafer 200 reach the top plate 20. The first partition 18a, the second partition 18b, the third partition 18c, the fourth partition 18d, and the top plate 20 are an example of a partition member.

[0044] The first partition 18a and the second partition 18b form a central portion 222b of the divided portions of the supply buffer 222. Return nozzles 340 and 341 that supply source gases are provided in the central portion 222b.

[0045] At the boundary between the central portion 222b of the supply buffer 222 and the cylindrical portion, a fan shape is formed by an imaginary arc connecting both circumferential ends of the cylindrical portion and the center C1 of the wafer 200. In this embodiment, the central angle θ of the fan shape is less than 30 degrees. If the central angle θ were 30 degrees or more, the circumferential width of the cylindrical portion of the supply buffer 222 would be wider, and more gas nozzles would need to be provided in the supply buffer 222. This would increase manufacturing costs and equipment downtime even if inexpensive tubular nozzles were used.

[0046] Furthermore, it is more preferable that the central angle θ of the sector is 15 degrees or more and 45 degrees or less. If the central angle θ of the sector is less than 15 degrees, it becomes difficult to uniformly expose the entire surface of the wafer to the source gas. Furthermore, if the central angle θ of the sector exceeds 45 degrees, the advantage of this example in which multiple nozzles are arranged is lost for the above-mentioned reasons. In the present disclosure, the central angle of the sector can be set arbitrarily.

[0047] 2, a supply slit 235b is formed in a central portion 222b of the supply buffer 222 on the inner circumferential surface 12a of the inner tube 12 on the supply slits 235a and 235c side. As shown in Fig. 3, the supply slit 235b opens over the entire central portion 222b in the vertical direction H of the apparatus and the entire width direction W of the apparatus. Therefore, the entire return nozzles 340 and 341 in the vertical direction H of the apparatus and the entire width direction W of the apparatus face the wafer 200 inside the cylindrical portion.

[0048] (1st injection device) The return nozzles 340 and 341, which are multiple gas nozzles, are provided inside the supply buffer 222 and extend along the axial direction of the cylindrical portion. Specifically, four nozzles, including two gas nozzles 340a and 340b and two gas nozzles 341a and 341b, are arranged along the circumferential direction of the cylindrical portion and are configured to be able to supply the same source gas. The four gas nozzles 340a, 340b, 341a, and 341b in this embodiment correspond to the multiple gas nozzles of the present disclosure.

[0049] (return nozzle) In this embodiment, the four gas nozzles 340a, 340b, 341a, and 341b are formed by two return nozzles 340 and 341. That is, the gas nozzles 340a and 340b adjacent to each other on the lower side in the width direction W in FIG. 2 are formed by one return nozzle 340, and the gas nozzles 341a and 341b adjacent to each other on the upper side opposite the gas nozzles 340a and 340b in the width direction W are formed by another return nozzle 341. In the present disclosure, two nozzles may be formed by only one return nozzle.

[0050] In addition, in the present disclosure, the number of return nozzles 340, 341 may be one, or may be any number of two or more. In addition, in the present disclosure, the multiple nozzles do not necessarily have to be return nozzles, and may be, for example, an arrangement of multiple nozzles that are independent of each other (nozzle array).

[0051] As shown in FIG. 3, the return nozzle 340 has an outward pipe corresponding to gas nozzle 340a and a return pipe corresponding to gas nozzle 340b, and the upper ends of the outward pipes and the return pipes are connected to each other, allowing source gas to flow through each pipe. The return nozzle 341 is configured plane-symmetrical to the return nozzle 340. The return pipes of the return nozzles 340 and 341 are adjacent to each other and spaced apart from each other. In this embodiment, the inner diameter of the outward pipe and the return pipe are the same. In the present disclosure, the inner diameter of the outward pipe and the return pipe may be different.

[0052] (Injection hole) The outward and return pipes of the return nozzles 340, 341 each have three or more rows of injection holes 234 extending along the longitudinal direction of the return nozzle. The injection holes 234 provide a cylindrical flow path connecting the inside and outside of the return nozzle. Such injection holes normally form a subsonic jet, but the velocity boundary layer formed may act like a Laval nozzle, thereby realizing a supersonic flow. The same source gas is injected from the injection holes 234. The source gas is injected radially in a plan view.

[0053] In the present disclosure, it is not essential that the gas nozzles 340a, 340b, 341a, and 341b have three or more rows of injection holes arranged in the vertical direction, but may have three or more injection holes arranged in the circumferential direction of the cylindrical portion in a plane parallel to the surface of the substrate. Also, in the present disclosure, the number of injection holes can be set arbitrarily to one, two, four or more.

[0054] Of the four gas nozzles 340a, 340b, 341a, and 341b arranged side by side in the central portion 222b of the supply buffer 222, the gas nozzles 340a and 341a on both sides in the width direction W inject the source gas toward the outermost sides of the wafer 200. Furthermore, of the three injection holes 234 provided in the gas nozzle 340a at the bottom in FIG. 2 which is the most opposite side in the width direction W to the gas nozzle 341a, the injection hole 234 most opposite in the width direction W to the gas nozzle 341a, and of the three injection holes 234 provided in the gas nozzle 341a at the top in FIG. 2 which is the most opposite side in the width direction W to the gas nozzle 340a, the injection hole 234 most opposite in the width direction W to the gas nozzle 340a, inject the source gas toward the outermost sides of the wafer 200.

[0055] 2, the injection direction of each injection hole 234 that injects the source gas toward the outermost side of the wafer 200 in a plan view is illustrated by a dotted arrow. A space is formed between the wafer 200 and each injection hole 234 that injects the source gas toward the outermost side of the wafer 200, allowing the source gas to travel straight along the injection direction. In other words, no other structure, such as a partition wall, is provided between the injection hole 234 and the wafer 200 in the injection direction. This disclosure does not exclude the placement of another structure between the wafer and at least one injection hole 234 that injects the source gas toward the outermost side of the wafer.

[0056] 5, in this embodiment, the diameter R1 of the injection holes 234 that injects the raw material gas toward the outermost side in a plan view from the center C1 of the wafer 200 (i.e., toward both ends in the width direction W of the apparatus in FIG. 5) is larger than the diameter R2 of the other injection holes 234. In the present disclosure, the diameter of the injection hole 234 that injects the raw material gas toward the outermost side from the center C1 of the wafer 200 may be equal to or smaller than the diameters of the other injection holes 234.

[0057] As shown in Figure 5, in this embodiment, the first injection direction F1, which is the injection direction of the injection hole 234 of the outward pipe of one return nozzle that is closest to the return pipe, and the second injection direction F2, which is the injection direction of the injection hole 234 of the return pipe that is closest to the outward pipe, intersect within the central portion 222b of the supply buffer 222 away from the wafer 200.

[0058] For example, the gas nozzle 340a of the return nozzle 340 on the left side of the imaginary plane A in Figure 5 is an outward pipe, and the gas nozzle 340b on the right side is a return pipe. Of the three injection holes 234 of the gas nozzle 340a of the outward pipe, the injection direction F1 of the rightmost injection hole 234 is closest to the gas nozzle 340b of the adjacent return pipe. Also, of the three injection holes 234 of the gas nozzle 340b of the return pipe, the injection direction F2 of the leftmost injection hole 234 is closest to the gas nozzle 340a of the adjacent outward pipe.

[0059] The injection direction F1 of the rightmost injection hole 234 of the gas nozzle 340a of the outward pipe and the injection direction F2 of the leftmost injection hole 234 of the gas nozzle 340b of the return pipe intersect at an intersection FX. In Figure 5, the intersection FX is illustrated inside the central portion 222b of the supply buffer 222. Similarly, in the two gas nozzles 341a, 341b of the return nozzle 341 on the right side of the imaginary plane A in Figure 5, the intersection FX of the first injection direction F1 and the second injection direction F2 is illustrated inside the central portion 222b of the supply buffer 222.

[0060] In this embodiment, the inner diameters of the forward and return pipes have the same radius r. The first injection direction F1 and the second injection direction F2 intersect outside the wafer 200, i.e., at a position away from the wafer 200, within a distance of 3r from the center C2 of the forward and return pipes in a plan view. Similarly, an intersection FY of the injection directions between the gas nozzle 340b of the return nozzle 340 and the gas nozzle 341b of the adjacent return nozzle 341 can be defined. Similar to the intersection FX, the intersection FY is located away from the wafer 200, within a distance of 3r from the center C2 of the forward and return pipes. Furthermore, matching the distance between the center C2 and the intersection FX and the distance between the center C2 and the intersection FY may result in more uniform gas mixing.

[0061] In the present disclosure, the position of the intersection of the first ejection direction and the second ejection direction is not limited to the position of the intersection in this embodiment. Also, it is possible to realize only a state in which the first ejection direction F1 and the second ejection direction F2 intersect within the supply buffer 222 away from the wafer 200. Also, when the inner diameter of the forward pipe and the inner diameter of the return pipe have the same radius r, it is possible to realize only a state in which the first ejection direction F1 and the second ejection direction F2 intersect at a position away from the wafer 200 within a distance of 3r from the center C2 of the forward pipe and within a distance of 3r from the center C2 of the return pipe in a plan view.

[0062] <Exhaust slit> 2, a plurality of exhaust slits, including a main exhaust slit 236 and a sub-exhaust slit 238, are formed in the sidewall of the cylindrical portion to exhaust the source gas from inside the cylindrical portion. In the present disclosure, the main exhaust slit 236 is not essential.

[0063] (Main exhaust slit) The main exhaust slit 236 is formed in the sidewall of the cylindrical portion on the opposite side of the supply buffer 222 with respect to the center C1 of the wafers 200. The main exhaust slit 236 opens on the side of each wafer 200 and exhausts the source gas and the like that has flowed over the wafers 200. The main exhaust slit 236 can be formed as a single opening extending between the side of the uppermost wafer 200 and the side of the lowermost wafer 200, or as multiple holes distributed between them.

[0064] (Secondary exhaust slit) The two sub-exhaust slits 238 are open on either side of an imaginary plane A set inside the cylindrical portion. As shown in Fig. 2, imaginary plane A is set to pass through the axis of the cylindrical portion and the circumferential center of the cylindrical portion at the boundary between the supply buffer 222 and the cylindrical portion in a plan view. The axis of the cylindrical portion overlaps with the center of the wafer 200.

[0065] The two sub-exhaust slits 238 form a pair of exhaust slits, sandwiching the main exhaust slit 236 at the same height as the main exhaust slit 236. In a plan view, a first virtual line L1 is set connecting the center of each sub-exhaust slit 238 and the center C1 of the wafer 200. In this embodiment, the angle between the first virtual line L1 and the virtual plane A is an obtuse angle. In the present disclosure, the angle between the first virtual line L1 and the virtual plane A is not limited to an obtuse angle.

[0066] 2, the width of each of the two sub-exhaust slits 238 in the circumferential direction of the cylindrical portion is smaller than the width of the main exhaust slit 236 at the same height. In the present disclosure, the width of the sub-exhaust slit 238 may be equal to or greater than the width of the main exhaust slit 236.

[0067] 2, the return nozzles 340, 341 and the two sub-exhaust slits 238 are configured symmetrically with respect to an imaginary plane A. In the present disclosure, it is not essential that the return nozzles 340, 341 and the pair of exhaust slits are configured symmetrically with respect to the imaginary plane A.

[0068] As shown in Fig. 4, in this embodiment, the opening width W1 of the main exhaust slit 236 along the circumferential direction of the cylindrical portion narrows from the side opposite the exhaust port 230 (i.e., the upper side in Fig. 4) toward the exhaust port 230 (i.e., the lower side in Fig. 4) along the axial direction of the cylindrical portion. Similarly, the opening width of each of the pair of sub-exhaust slits 238 along the circumferential direction of the cylindrical portion narrows from the side opposite the sub-exhaust port (i.e., the upper side in Fig. 4) toward the sub-exhaust port (i.e., the lower side in Fig. 4) along the axial direction of the cylindrical portion. The sub-exhaust ports are not shown in the figure.

[0069] In the present disclosure, the opening width along the circumferential direction of the cylindrical portion of each of the main exhaust slit 236 and the pair of sub-exhaust slits 238 can be set arbitrarily. For ease of viewing, the counter buffer is not shown in Figure 4. The counter buffer will be described later.

[0070] (tank) 1, the substrate processing apparatus 10 according to this embodiment further includes tanks 322b and 322c connected to the return nozzles 340 and 341. The tanks 322b and 322c can store the source gas alone so that the source gas is not mixed with the carrier gas. The tanks 322b and 322c supply the stored source gas in pulses to the return nozzles 340 and 341 almost simultaneously through on-off valves.

[0071] That is, in this embodiment, a flush supply of a high-concentration source gas can be performed. In the flush supply, the source gas stored in the tanks 322b and 322c is supplied from the tanks 322b and 322c toward the reaction tube 203 at a high flow rate. The source gas supplied at a high flow rate is also called a "flash flow." The flush flow source gas flows at a relatively high speed over the surface of the wafer 200 inside the cylindrical portion of the inner tube 12 during the film formation process.

[0072] By flush supply, the entire surface of the wafer 200 is exposed to a high-speed flow of source gas during the film formation process. A high-speed gas flow is one of the most effective means for promoting gas replacement inside fine structures such as trenches and holes formed on the surface of the wafer 200, and is particularly useful in processing patterned wafers with high aspect ratios.

[0073] The present disclosure is not limited to flush supply of raw material gases, and may be applied to, for example, ammonia (NH) or the like as a purge gas at a large flow rate using a general MFC. Therefore, in the present disclosure, the flush supply tanks 322b and 322c are not essential.

[0074] In this embodiment, the total maximum instantaneous flow rate of the source gases injected in pulses from each of the return nozzles 340 and 341 is 1 slm or more and 300 slm or less. If the total maximum instantaneous flow rate of the source gases is less than 1 slm, the flow rate will be insufficient, causing the source gas to change quality as it flows over the wafer 200 or insufficient gas replacement within the microstructure, resulting in reduced film quality and uniformity. Furthermore, if the total maximum instantaneous flow rate of the source gases exceeds 300 slm, the replacement promotion effect will saturate while the source gas flow rate will become too large, resulting in increased source gas costs.

[0075] Furthermore, it is more preferable that the total instantaneous maximum flow rate of the source gases is 12 slm or more and 50 slm or less. If the total instantaneous maximum flow rate of the source gases is less than 12 slm, the flow velocity on the wafer 200 may not be sufficiently high (e.g., 10 m / s or more), resulting in insufficient step coverage of the formed film. Furthermore, if the total instantaneous maximum flow rate of the source gases exceeds 50 slm, the configuration of the supply system for storing the source gases in a tank at high pressure without decomposing them becomes complicated, increasing the cost of the device. In the present disclosure, the total instantaneous maximum flow rate of the source gases injected in a pulsed manner is not limited to this and can be changed as appropriate.

[0076] (Second injection device) 2, the substrate processing apparatus 10 according to this embodiment further includes gas nozzles 342a and 342c as second injectors for supplying an assist gas. The gas nozzles 342a and 342c are provided in the portions 222a and 222c on both sides of the supply buffer 222, respectively. In the present disclosure, the second injectors are not essential. Note that the second injectors are not limited to tubular members such as nozzles, as long as they are capable of injecting a source gas.

[0077] As shown in Fig. 2, partition walls are provided between the cylindrical portion and both side portions 222a, 222c in the width direction W of the supply buffer 222. Furthermore, as shown in Fig. 3, supply slits 235a, 235c are formed in the partition walls. The gas nozzles 342a, 342c have a plurality of injection holes 344 arranged in the vertical direction.

[0078] (Third injection device) 2, the substrate processing apparatus 10 according to this embodiment further includes a counter-nozzle 343 as a third spraying device that supplies an assist gas. One or more counter-nozzles 343 can be provided as counter-nozzles at positions where, in a plan view, the angle between a second imaginary line L2 connecting the spraying direction of the counter-nozzle 343 and the center C1 of the wafer 200 and the imaginary plane A is an obtuse angle.

[0079] The counter-nozzle 343 is housed inside the counter-buffer 222d. Similar to the supply buffer 222, the counter-buffer 222d is a region provided on the side wall of the cylindrical portion of the inner pipe 12 and protruding outward from the side wall. The counter-buffer 222d may be provided between the main exhaust slit 236 and the two sub-exhaust slits 238 in the circumferential direction of the cylindrical portion, or between the supply buffer 222 and the two sub-exhaust slits 238. In the present disclosure, the counter-nozzle 343 is not essential. A temperature sensor may be disposed in the counter-buffer 222d. Note that the third injection device is not limited to a tubular member such as a nozzle, as long as it is capable of injecting the process gas.

[0080] (Control unit) Next, the control unit 280 will be described with reference to Fig. 6. Fig. 6 is a block diagram showing the substrate processing apparatus 10, and the control unit 280 (i.e., controller) of the substrate processing apparatus 10 is configured as a computer. This computer includes a CPU (Central Processing Unit) 121a, a RAM (Random Access Memory) 121b, a storage device 121c, and an I / O port 121d.

[0081] The RAM 121b, the storage device 121c, and the I / O port 121d are configured to be able to exchange data with the CPU 121a via an internal bus 121e. The control unit 280 is connected to an input / output device 122 configured as, for example, a touch panel.

[0082] The storage device 121c is configured with, for example, a flash memory, an HDD (Hard Disk Drive), etc. A control program for controlling the operation of the substrate processing apparatus, a process recipe describing procedures and conditions for substrate processing (to be described later), etc. are readably stored in the storage device 121c.

[0083] A process recipe is a combination of procedures in a substrate processing step, which will be described later, that are executed by the control unit 280 to obtain a predetermined result, and functions as a program. Hereinafter, the process recipe, control program, etc. will be collectively referred to simply as a program.

[0084] In this specification, when the word "program" is used, it may include only a process recipe, only a control program, or both. The RAM 121b is configured as a memory area (i.e., a work area) where programs and data read by the CPU 121a are temporarily stored.

[0085] The I / O port 121d is connected to the above-mentioned MFCs 320a to 320d, valves 330a to 330d, pressure sensor 245, APC valve 244, vacuum pump 246, heater 207, temperature sensor, rotation mechanism 267, elevator 115, and the like.

[0086] The CPU 121a is configured to read and execute a control program from the storage device 121c, and also to read a process recipe from the storage device 121c in response to an input of an operation command from the input / output device 122, etc.

[0087] The CPU 121a is configured to control the flow rate adjustment operations of various gases by the MFCs 320a to 320d, the opening and closing operations of the valves 330a to 330d, and the opening and closing operation of the APC valve 244, in accordance with the contents of the read process recipe. The CPU 121a is also configured to control the pressure adjustment operation by the APC valve 244 based on the pressure sensor 245, the start and stop of the vacuum pump 246, and the temperature adjustment operation of the heater 207 based on the temperature sensor. The CPU 121a is also configured to control the rotation and rotation speed adjustment operation of the boat 217 by the rotation mechanism 267, the lifting and lowering operation of the boat 217 by the elevator 115, etc.

[0088] The control unit 280 is not limited to being configured as a dedicated computer, but may also be configured as a general-purpose computer. For example, the control unit 280 of this embodiment can be configured by preparing an external storage device 123 storing the above-mentioned program and installing the program in a general-purpose computer using this external storage device 123. Examples of external storage devices include magnetic disks such as hard disks, optical disks such as CDs, magneto-optical disks such as MOs, and semiconductor memories such as USB memories.

[0089] <Substrate processing method> Next, a substrate processing method using the substrate processing apparatus 10 according to this embodiment will be described with reference to Fig. 7. In this embodiment, as an example of a semiconductor device manufacturing process, a cycle process will be described in which a film formation process is performed by alternately supplying a source gas and a reactive gas to a processing chamber.

[0090] In the cycle process, a Si source gas is used as an example of a source, and an N-containing gas is used as a reactant, whereby a Si nitride film (Si 3 N 4 film, hereinafter also referred to as a SiN film) is formed on the wafer 200.

[0091] The SiN film is formed by performing a cycle of non-simultaneously performing film formation process 1 in step S3, film formation process 2 in step S4, film formation process 3 in step S5, and film formation process 4 in step S6 in Figure 7 one or more times.

[0092] Film formation process 1 is a process of supplying raw material gas to wafers 200 in inner tube 12. Film formation process 2 is an exhaust process of removing remaining raw material gas from inner tube 12. Film formation process 3 is a process of supplying N-containing gas as a reaction gas to wafers 200 in inner tube 12. Film formation process 4 is an exhaust process of removing remaining reaction gas from inner tube 12.

[0093] First, in step S1 in Fig. 7, wafers 200 are loaded into a boat 217. The boat 217 is carried into the inner tube 12, thereby accommodating the substrates inside the cylindrical portion of the inner tube 12. Next, in step S2 in Fig. 7, after the boat 217 is carried into the inner tube 12, the pressure and temperature inside the inner tube 12 are adjusted. Next, four steps of film formation processes 1 to 4 are executed in sequence. Each step will be described in detail below.

[0094] (Film forming process 1) 7, in the film forming process 1, the first injector is used to inject the source gas toward the wafer 200, while the main exhaust slit 236 and the two sub-exhaust slits 238 are used to exhaust the injected source gas to the outside of the cylindrical portion. Specifically, a flush supply is performed one or more times, in which the source gas and the carrier gas are instantaneously discharged from the gas nozzles 340a, 340b, 341a, and 341b, i.e., in a relatively short time. At this time, an assist gas may be injected from the gas nozzles 342a and 342c or the counter nozzle 343. When multiple flush supplies are performed intermittently, the flow rate of the assist gas may change accordingly.

[0095] The source gas may be, for example, a gas containing Si and a halogen. The Si- and halogen-containing gas may be, for example, an inorganic chlorosilane-based gas such as tetrachlorosilane (SiCl4, abbreviated as STC) gas, hexachlorodisilane (Si2Cl6, abbreviated as HCDS) gas, or octachlorotrisilane (Si3Cl8, abbreviated as OCTS) gas. The Si- and halogen-containing gas may be, for example, one or more of these.

[0096] In this disclosure, a "large flow rate" means a mass flow rate [kg / s] of 8×10 -4 kg / s or more. 8×10 -4 A mass flow rate [kg / s] of 8×10 kg / s or more corresponds to a volumetric flow rate [slm] of 4 slm or more of HCDS gas. -4A mass flow rate [kg / s] of 38 slm or more corresponds to a volumetric flow rate [slm] of N2 gas of 38 slm or more. In this specification, 1 slm is defined as 1 L / m. At high flow rates, various difficulties in gas supply can occur, such as vortices and backflows within the processing chamber 201.

[0097] The volumetric flow rate [slm] is calculated by dividing the mass flow rate by the density of the gas species. Therefore, the volumetric flow rate can be used as a flow rate applicable to the present disclosure regardless of the gas species. Typical high flow volumetric flow rates for gases used in applicable film species include, for example, titanium tetrachloride (TiCl4) at approximately 5.5 slm or more, oxygen (O2) at approximately 30 slm or more, trimethylaluminum (TMA) at approximately 15 slm or more, and NH3 at approximately 65 slm or more.

[0098] By performing the flush supply operation intermittently, the source gas is adsorbed onto the surface of the wafer 200. By the adsorption, a film containing Si is formed on the base film of the wafer 200. The substrate processing method according to this embodiment can be configured by the above steps S1 and S3.

[0099] (Film formation process 2) In the film formation process 2, first, in step S4 in Fig. 7, the supply of the source gas and the carrier gas is stopped. Next, by controlling an exhaust pump such as the vacuum pump 246 and the APC valve 244, the source gas is evacuated so that the pressure inside the reaction tube 203 reaches a predetermined pressure (i.e., vacuum degree). By evacuating, the source gas remaining in the inner tube 12 is exhausted from the inner tube 12 to the outside. In the film formation process 2, if an inert gas, for example, N2 gas, is supplied into the inner tube 12 as a purge gas, the effect of exhausting the remaining source gas is further enhanced.

[0100] (Film forming process 3) In the film forming process 3, in step S5 in FIG. 7, a reactive gas is supplied into the inner tube 12 using the second injection device. Examples of the reactive gas include N-containing gas, non-Si-containing gas, oxidizing gas, and reducing gas such as hydrogen (H2). In step S5, for example, NH3 gas is supplied as the reactive gas into the inner tube 12 while being exhausted through multiple exhaust slits. The supply of the N-containing gas causes a reaction between the Si-containing film on the base film of the wafer 200 and the N-containing gas. A SiN film is formed on the wafer 200 through this reaction. Alternatively, if a mixture of O2 and H2 gas is used as the reactive gas, SiO2 is formed.

[0101] (Film forming process 4) 7, after forming a film, the reaction gas is evacuated by controlling an exhaust pump such as the vacuum pump 246 and the APC valve 244, etc., so that the pressure inside the reaction tube 203 reaches a predetermined pressure (vacuum level). By evacuating, the N-containing gas remaining in the inner tube 12 after contributing to film formation is exhausted from the inner tube 12 to the outside. In the film formation process 4, if an inert gas, for example, N gas used as a carrier gas, is supplied into the inner tube 12 as a purge gas, the effect of exhausting the remaining N-containing reaction gas from the inner tube 12 is further enhanced.

[0102] The above-described film formation steps 1 to 4 constitute one cycle, and in step S7 in FIG. 7, the cycle of film formation steps 1 to 4 is performed a predetermined number of times to form a SiN film with a predetermined thickness on wafer 200. In this embodiment, film formation steps 1 to 4 are repeated multiple times. In the present disclosure, film formation steps 1 to 4 may be performed one at a time without being repeated.

[0103] In film formation using a cyclic process such as this example, one gas among multiple process gases may be dominant in terms of film quality, particularly uniformity. For example, if uniform adsorption of a chlorosilane-based source gas onto adsorption sites within a microstructure is important for good step coverage, only the source gas may be supplied planarly by the first injector. As a result, both the flow rate and partial pressure of the source gas or intermediate gas on the wafer surface may be maintained within a predetermined range. On the other hand, the wafer's exposure to the reactive gas does not require the same uniformity as the source gas.

[0104] After the above-described film formation process is completed, in step S8 in Fig. 7, the pressure inside the inner tube 12 is returned to normal pressure (i.e., atmospheric pressure). Specifically, for example, an inert gas such as N2 gas is supplied into the inner tube 12 and then exhausted. This causes the inside of the inner tube 12 to be purged with the inert gas, and any gas remaining inside the inner tube 12 is removed from the inside of the inner tube 12. Thereafter, the atmosphere inside the inner tube 12 is replaced with the inert gas, and the pressure inside the inner tube 12 is returned to normal pressure.

[0105] 7, the substrate processing according to this embodiment is completed by unloading the wafer 200 from the inner tube 12. The above series of steps constitutes a method for manufacturing a semiconductor device using the wafer 200 according to this embodiment.

[0106] The term "wafer" used in this specification may refer to the wafer itself or to a laminate of the wafer and a predetermined layer or film formed on its surface. The term "surface of a wafer" used in this specification may refer to the surface of the wafer itself or to the surface of a predetermined layer or the like formed on the wafer. When described in this specification, "forming a predetermined layer on a wafer" may mean forming a predetermined layer directly on the surface of the wafer itself or forming a predetermined layer on a layer or the like formed on the wafer. When used in this specification, the term "substrate" is synonymous with the term "wafer".

[0107] (Analysis example) Next, first to third analysis examples for confirming the characteristics of the substrate processing apparatus according to this embodiment will be described with reference to FIGS.

[0108] (1st analysis example) First, a first analysis example will be described, in which the center-to-center distance between two straight nozzles is analyzed. Fig. 8 illustrates the distribution of source gas concentration inside the cylindrical portion when the center-to-center distance d between two gas nozzles 345 corresponding to gas nozzles 340b and 341b in the substrate processing apparatus according to this embodiment is 22 mm. In the first analysis example, the substrate processing apparatus is not provided with a sub-exhaust slit, but is provided with only a main exhaust slit.

[0109] 8, even without providing a sub-exhaust slit, providing two gas nozzles 345 generally reduces unevenness in the source gas concentration distribution on the substrate compared to the case where there is one gas nozzle 345. Figure 8 illustrates a state in which the portions with a relatively high source gas concentration are located on the outer edges of both sides of the substrate, on the main exhaust slit side in the depth direction D of the apparatus.

[0110] Figure 9 also shows the analysis results of the relationship between the uniformity of source gas concentration and the center-to-center distance d between two gas nozzles. Each gas nozzle had three injection holes. As shown in Figure 9, the uniformity of source gas concentration on the substrate is expressed as the standard deviation [±%] relative to the average concentration [%]. The average concentration [%] is the concentration of source gas per unit area over the entire substrate surface.

[0111] 9 also plots a value of 25% as the uniformity of the source gas concentration when the center-to-center distance d between the two gas nozzles is 0 mm, which means that there is one gas nozzle.

[0112] As shown in Figure 9, when the center-to-center distance d between the two gas nozzles is between 20 mm and 100 mm, the standard deviation is kept to approximately 14% or less, which improves the uniformity of the source gas concentration. If the center-to-center distance d exceeds 100 mm, the dimensions of the supply buffer become large, which raises concerns about the bulkiness of the inner tube.

[0113] In addition, when the center-to-center distance d between the two gas nozzles is 40 mm or more and 100 mm or less, the standard deviation is suppressed to approximately 7% or less, which further improves the uniformity of the source gas concentration. Furthermore, when the center-to-center distance d between the two gas nozzles is 60 mm or more and 80 mm or less, the standard deviation is suppressed to approximately 3% or less, which further improves the uniformity of the source gas concentration.

[0114] (Second analysis example) Next, a second analytical example will be described, in which the flow of the source gas inside the cylindrical portion of the inner tube and the distribution of the partial pressure [Pa] of the intermediate are analyzed. In the second analytical example, an inorganic chlorosilane gas is used as the source gas, and the intermediate is SiCl2 generated by decomposition of the source gas. The source gas is supplied to the wafer at a large flow rate by four gas nozzles. Note that in Figures 10A to 10C, the flow of the source gas is symmetrical across imaginary plane A, so only the state on the left side is illustrated, and the state on the right side is omitted.

[0115] 10A illustrates the flow and partial pressure distribution of the source gas in an analytical model of the substrate processing apparatus according to this embodiment, in which the gas nozzles 340a and 340b each have a single row of injection holes and the only exhaust slit is the main exhaust slit 236. In other words, the pair of sub-exhaust slits 238 are not provided.

[0116] In the analytical model of Fig. 10A, as shown in the upper part, a return flow, i.e., a vortex, was formed when the source gas was supplied from the gas nozzles 340a and 340b to the vicinity of the gas nozzle 342a. Also, as shown in the lower part of Fig. 10A, a high intermediate partial pressure of approximately 10 Pa was formed on the wafer at positions corresponding to both sides of the imaginary plane A across the entire depth direction D, and a concentration gradient was distributed across the entire wafer. A high intermediate partial pressure suggests a relatively low flow velocity.

[0117] 10B illustrates the flow and partial pressure distribution of the source gas in an analytical model in which the substrate processing apparatus according to this embodiment has three rows of injection holes in each of the gas nozzles 340a and 340b and only one exhaust slit, the main exhaust slit 236. Other analytical conditions are the same as those in the case of FIG. 10A.

[0118] In the analytical model of Fig. 10B, as shown in the upper part, no return flow was formed. Furthermore, as shown in the lower part of Fig. 10B, the partial pressure concentration of the intermediate body was distributed relatively uniformly except for the side portions in the width direction W, which was an improvement over the case of Fig. 10A. Specifically, in the positions corresponding to both sides of the wafer and on the gas nozzle 340a, 340b side in the depth direction D, the partial pressure concentration of the source gas was suppressed to 10 Pa or less.

[0119] 10C illustrates the flow and partial pressure distribution of the source gas in an analytical model of the substrate processing apparatus according to this embodiment, in which the gas nozzles 340a and 340b each have three rows of injection holes and are provided with one main exhaust slit 236 and two sub-exhaust slits 238. Other analytical conditions are the same as those in the case of FIG. 10A.

[0120] In the analytical model of Fig. 10C in which two sub-exhaust slits 238 were added, no return flow was formed, as shown in the upper part. It was also found that the two sub-exhaust slits 238 formed a flow of source gas flowing at a position corresponding to the vicinity of the outer edge of the side of the wafer. Furthermore, as shown in the lower part of Fig. 10C, the deviation in the partial pressure of the intermediate was clearly reduced compared to the cases of Fig. 10A and Fig. 10B.

[0121] (Third analysis example) Next, a third analytical example will be described, in which the return flow inside the cylindrical portion of the inner tube was analyzed. As shown in Fig. 11, in the third analytical example, the presence or absence of the return flow was evaluated for each pattern in which the shape of the injection holes was changed when the source gas was injected from two gas nozzles 340a, 340b. The analytical conditions for the simulation of the third analytical example, such as pressure, temperature, and gas type, were set to simulate those used in an actual film formation process.

[0122] As shown in Figure 11, the presence or absence of backflow was evaluated on a three-point scale: "◎", "△", and "×". "◎" means that there was no or almost no backflow. "△" means that a weak backflow was observed. "×" means that a strong backflow was present.

[0123] In the third analytical example, five patterns were set according to the different shapes of the gas nozzles 340a, 340b. In the first pattern, the number of injection holes in each of the two gas nozzles 340a, 340b was one, and the diameter of the injection hole was 4.6 mm.

[0124] In the second pattern, the number of injection holes in each of the two gas nozzles 340a, 340b was two along the circumferential direction of the gas nozzles 340a, 340b. In the second pattern, the injection holes were arranged so that the angle between the injection direction of each injection hole and the direction from the center of the gas nozzles 340a, 340b toward the center of the wafer was 30 degrees in plan view. The diameter of the injection holes was 1.9 mm.

[0125] In the third pattern, the number of injection holes in each of the two gas nozzles 340a and 340b was three along the circumferential direction of the gas nozzle. In the third pattern, the injection holes were arranged so that the angle between adjacent injection holes was 30 degrees in plan view. In addition, the injection direction of the central injection hole of the three injection holes was aligned from the center of the gas nozzles 340a and 340b toward the center of the wafer in plan view. The diameter of the injection hole was 1.9 mm.

[0126] In the fourth pattern, the number of injection holes in each of the two gas nozzles 340a, 340b was four along the circumferential direction of the gas nozzle. In the fourth pattern, the injection holes were arranged so that the angle between adjacent injection holes was 30 degrees in plan view. Furthermore, the injection holes were arranged so that the angle between the injection direction of the central two injection holes and the direction from the center of the gas nozzles 340a, 340b toward the center of the wafer was 30 degrees in plan view. The diameter of the injection holes was 1.9 mm.

[0127] In the fifth pattern, the number of injection holes in each of the two gas nozzles 340a, 340b was four along the circumferential direction of the gas nozzle 340b. In the fifth pattern, the injection holes were arranged so that the angle between adjacent injection holes was 20 degrees in plan view. Furthermore, the injection holes were arranged so that the angle between the injection direction of the central two injection holes and the direction from the center of the gas nozzles 340a, 340b toward the center of the wafer was 20 degrees in plan view.

[0128] That is, in the fourth pattern, the injection range centered in the direction from the center of the gas nozzles 340a and 340b toward the center of the wafer was set wider than the injection range in the fifth pattern. The diameter of the injection hole was 1.9 mm.

[0129] Furthermore, the inner diameter and thickness of the cylinders of the gas nozzles 340a, 340b were set to be the same throughout the first to fifth patterns. In the first pattern, a partition was provided between the central portion 222b of the supply buffer 222, where the gas nozzles 340a, 340b are arranged, and the cylindrical portion of the inner tube 12, and a slit opening opposite the injection holes, such as the supply slit 235a in FIG. 3, was also provided. On the other hand, in all of the second to fifth patterns, as in this embodiment shown in FIG. 3, no partition was provided between the central portion 222b of the supply buffer 222, where the gas nozzles 340a, 340b are arranged, and the cylindrical portion of the inner tube 12.

[0130] In the third analysis example, the flow rate per gas nozzle was varied to five levels: 1 slm, 5 slm, 12 slm, 20 slm, and 50 slm. As a result of the analysis, as shown in Figure 11, in the first pattern, a backflow was continuously present at flow rates per gas nozzle of 5 slm, 12 slm, 20 slm, and 50 slm. In the second pattern, it was found that the smaller the flow rate per gas nozzle, the more the occurrence of a backflow was suppressed.

[0131] In addition, in the cases of the third, fourth, and fifth patterns, it was found that no backflow occurred except when the flow rate per gas nozzle was 50 slm in the fourth pattern. When the flow rate per gas nozzle was 50 slm in the fourth pattern, the injection range centered on the direction from the center of the gas nozzles 340a and 340b toward the center of the wafer was wider than the injection range in the fifth pattern, so the flow of source gas from the injection holes collided with the side wall of the supply buffer close to the injection holes. As a result, a backflow continuously existed.

[0132] In addition, in another analysis example, even when the flow rate per gas nozzle is 50 slm in the fourth pattern, no other structures such as the side walls of the supply buffer are placed near the gas nozzles 340a and 340b. As a result, it was found that the flow of source gas is not blocked by the other structures.

[0133] <Modification> Next, substrate processing apparatuses according to first to sixth modified examples will be described with reference to Figures 12 to 13. In the first to sixth modified examples, the inner structure of the supply buffer 222 differs from that of this embodiment.

[0134] (First Modification) As shown in Fig. 12A, in the present disclosure, the number of gas nozzles 340a, 340b, 341a, and 341b constituting the first injector can be one or more, and can be changed as appropriate. Fig. 12A illustrates a substrate processing apparatus according to a first modification, in which six gas nozzles corresponding to gas nozzle 340a and the like constituting the first injector are provided. The first modification also provides the same effects as the present embodiment.

[0135] (Second Modification) 12B, in the second modification, a plurality of gas nozzles corresponding to gas nozzle 340a and the like are arranged at a distance from wafer 200. Specifically, supply buffer 222 is configured so that a certain distance M is formed between the center of each gas nozzle and wafer 200. In this embodiment, the certain distance M is preferably, for example, at least two times the Kolmogorov length and at most ten times the Kolmogorov length.

[0136] If the fixed distance M is less than twice the Kolmogorov length of the gas flow from the gas nozzle, the source gas will impinge on the wafer 200 without being sufficiently homogenized. If the fixed distance M is more than 10 times the Kolmogorov length, there is a concern that the substrate processing apparatus will become too large. Note that, in this embodiment, the fixed distance can be set arbitrarily.

[0137] The second modification also provides the same effects as the present embodiment. Furthermore, in the second modification, the multiple gas nozzles are arranged away from the wafer 200, which promotes mixing of the source gases injected from the multiple gas nozzles before they reach the wafer 200. This allows the source gases, the mixing of which has been promoted, to be sent onto the surface of the wafer 200.

[0138] (Third Modification) As shown in FIG. 12C , in the third modification, the injection holes of the plurality of gas nozzles 345, which correspond to the gas nozzle 340a and the like, open toward the sidewall opposite the wafer 200 (i.e., the upper side in FIG. 12C ). The third modification also provides the same effects as the present embodiment. Furthermore, in the third modification, the injection holes of the plurality of gas nozzles 345 open toward the sidewall opposite the wafer 200, so that the injected source gas collides with the sidewall opposite the wafer 200. The source gas that collides with the sidewall opposite the wafer 200 heads toward a ventilation slit 380a in a partition wall 380 provided between the gas nozzle 345 and the wafer 200. The source gas reaches the wafer 200 through the ventilation slit 380a.

[0139] The ventilation slit 380a of the third modified example is an example of a ventilation hole having an opening. In the present disclosure, the shape of the opening of the ventilation hole formed in the partition wall is not limited to a slit shape and can be arbitrarily changed, for example, to a hole shape. In the present disclosure, the ventilation hole is an example of a ventilation part formed between the gas nozzle 345 and the wafer 200 to pass the source gas toward the wafer 200. Also, in the present disclosure, the ventilation part is not limited to a ventilation hole in the partition wall. For example, a ventilation device having an overall tubular shape and having a gas flow path formed inside may be provided as the ventilation part.

[0140] Therefore, in the third modification, mixing of the source gases is promoted after the source gases are ejected from the gas nozzle 345 and before they reach the wafer 200. As a result, the source gases whose mixing is promoted can be sent onto the surfaces of the wafers 200.

[0141] (Fourth Modification) 12D, in the fourth modification, the injection holes of the multiple gas nozzles corresponding to gas nozzle 340a and the like are opened toward a sidewall provided between the gas nozzle and wafer 200. In the fourth modification, the same effects as in the present embodiment can be obtained. Furthermore, in the fourth modification, the injection holes of the multiple gas nozzles are opened toward a partition wall 380 provided between the gas nozzle and wafer 200, so that the injected source gas collides with the partition wall 380.

[0142] The source gas that collides with the partition wall 380 passes through the ventilation slits 380a of the partition wall 380 and reaches the wafer 200. Therefore, mixing of the source gases is promoted after the source gases are ejected from the gas nozzle 340b and before they reach the wafer 200. As a result, the source gases whose mixing is promoted can be sent onto the surfaces of the wafers 200.

[0143] (Fifth Modification) In the present disclosure, the configurations of the first to fourth modifications may be partially combined. For example, Fig. 12E illustrates a fifth modification in which the configurations of the second and fourth modifications are combined. That is, in the supply buffer 222 according to the fifth modification, similar to the second modification, multiple gas nozzles are disposed away from the wafer 200 so that a certain distance M is formed between the center of each gas nozzle and the wafer 200.

[0144] Furthermore, in the fifth modification, similarly to the fourth modification, a partition wall 380 having ventilation slits 380a is provided between the gas nozzle and wafer 200, and the injection holes of a plurality of gas nozzles corresponding to gas nozzles 340a and the like open toward partition wall 380 having ventilation slits 380a. Therefore, in addition to the same effects as the present embodiment, the fifth modification can also obtain the effects of both the second and fifth modifications.

[0145] (Sixth Modification) 13, in the substrate processing apparatus according to the sixth modification, the main exhaust slit 236 and the pair of sub-exhaust slits 238 are both rectangular in shape. In the sixth modification, fins 250 protruding from the side walls toward the outer tube 14 are provided as exhaust flow rate adjusters on parts of the side walls that form the main exhaust slit 236 and the pair of sub-exhaust slits 238 in the cylindrical portion.

[0146] The protruding length of the fins 250 provided on the side wall of the main exhaust slit 236 decreases along the axial direction of the cylindrical portion from the upper side in FIG. 13, which is the opposite side from the main exhaust port, to the lower side in FIG. 13, where the main exhaust port is located. The main exhaust port is not shown. The protruding length of the fins 250 provided on the side wall of the sub-exhaust slit 238 decreases along the axial direction of the cylindrical portion from the upper side in FIG. 13, which is the opposite side from the sub-exhaust port, to the lower side in FIG. 13, where the sub-exhaust port is located. The sub-exhaust port is not shown.

[0147] The sixth modification also provides the same effects as the present embodiment. Furthermore, in the sixth modification, the fins 250 can equalize the flow rate of the source gas exhausted between the substrates stacked in multiple stages along the axial direction of the cylindrical portion, i.e., equalize the conductance in the vertical direction. The effects of the sixth modification will be described in detail later.

[0148] 13 illustrates an example in which the fins 250 are formed in a stepped pattern using a plate-like member having five plate-like portions with increasing protruding lengths from top to bottom, but in the present disclosure, the shape of the exhaust flow rate adjuster is not limited to a stepped shape. For example, in the present disclosure, the exhaust flow rate adjuster may be formed using a plate-like member having plate-like portions with protruding lengths that gradually decrease toward the main exhaust port. Furthermore, the exhaust flow rate adjuster is not limited to a plate-like member, and may be formed using a solid member, an annular member, or the like.

[0149] (Seventh Modification) 10C , the substrate processing apparatus according to the seventh modification includes a main exhaust buffer 232a formed to airtightly cover the main exhaust slit 236 from the outside of the inner pipe 12, and two sub-exhaust buffers 232b formed separately from the main exhaust buffer to similarly cover the two sub-exhaust slits 238, respectively, from the outside of the inner pipe 12. The main exhaust buffer 232a and the sub-exhaust buffer 232b are each connected to the exhaust duct 231.

[0150] The main exhaust buffer 232a and the sub-exhaust buffer 232b, like the supply buffer 222, are formed on the outside of the inner tube, extending in the axial direction of the reaction tube along the distribution of the corresponding main exhaust slits 236 and sub-exhaust slits 238. The main exhaust buffer 232a reduces the pressure gradient therein and cooperates with the main exhaust slit 236 to provide uniform exhaust to the wafers 200. The same is true for the sub-exhaust buffer 232b.

[0151] The main exhaust buffer 232a corresponds to the main exhaust device that sends the source gas to the outside in this disclosure. The two sub-exhaust buffers 232b correspond to the two sub-exhaust devices that send the source gas to the outside in this disclosure. Note that in this disclosure, the main exhaust device is not limited to the main exhaust buffer, and may be any main exhaust space that can alleviate the internal pressure gradient. Similarly, in this disclosure, the sub-exhaust device is not limited to the sub-exhaust buffer, and may be any sub-exhaust space that can alleviate the internal pressure gradient.

[0152] The seventh modification also provides the same effects as the present embodiment. Furthermore, in the seventh modification, by providing the main exhaust buffer 232a and the like, the outer tube 14 is no longer necessary, and a processing vessel with a single-tube structure can be adopted. In this context, the term "processing tube" refers to each of the inner tube 12 and the outer tube 14, and may particularly include a single tube that has the same shape and pressure resistance as the inner tube 12 and is used alone.

[0153] (Action and effect) According to this aspect, one or more of the following effects can be obtained.

[0154] The substrate processing apparatus 10 according to this embodiment includes a reaction tube 203 having an inner tube 12 and an outer tube 14, a supply buffer 222 provided in the cylindrical portion of the inner tube 12, four gas nozzles 340a, 340b, 341a, 341b provided in the supply buffer 222, and two auxiliary exhaust slits 238 provided in the cylindrical portion.

[0155] The two sub-exhaust slits 238 are formed in the side wall of the cylindrical portion and open on both sides of an imaginary plane A that is set to pass through the circumferential center of the cylindrical portion at the boundary between the supply buffer 222 and the cylindrical portion and the axis of the cylindrical portion in a plan view. In other words, the two sub-exhaust slits 238 face both sides of the wafer 200 that are sandwiched between the imaginary plane A.

[0156] Therefore, the source gas injected from the four gas nozzles 340a, 340b, 341a, and 341b is promoted to flow not only toward the center of the wafer 200 in plan view, but also toward both sides of the wafer 200. As a result, the uniformity of the source gas flow on the surface of the wafer 200 can be improved during the film formation process.

[0157] Furthermore, in this embodiment, the uniformity of the flow of the source gas can be improved by simply forming two sub-exhaust slits 238 in the cylindrical portion on both sides of the imaginary plane A, so that no additional member is required. As a result, the substrate processing apparatus 10 can be configured relatively inexpensively and compactly.

[0158] In this embodiment, one main exhaust slit 236 is formed in the sidewall of the cylindrical portion on the opposite side of the supply buffer 222 with respect to the center C1 of the wafer 200. The two sub-exhaust slits 238 are disposed at the same height as the main exhaust slit 236 and spaced apart from it, sandwiching the main exhaust slit 236. In plan view, the angle between each first imaginary line L1 connecting the center of the sub-exhaust slit 238 and the center C1 of the wafer 200 and the imaginary plane A is an obtuse angle. The width of each of the two sub-exhaust slits 238 in the circumferential direction of the cylindrical portion is smaller than the width of the main exhaust slit 236.

[0159] The source gas is further dispersed by the main exhaust slit 236 and the two sub-exhaust slits 238, thereby reducing the area where the flow of the source gas decreases around the wafer 200. This further improves the uniformity of the flow of the source gas on the surface of the wafer 200.

[0160] In this embodiment, the four gas nozzles 340a, 340b, 341a, and 341b are arranged along the circumferential direction of the cylindrical portion and are configured to be able to supply the same source gas. Each of the four gas nozzles 340a, 340b, 341a, and 341b has an outgoing pipe and a returning pipe through which the source gas flows, and is a return nozzle having injection holes 234 that inject the same source gas by communicating the upper ends of the outgoing pipe and the returning pipe.

[0161] In this embodiment, the source gas is further dispersed by the four gas nozzles 340a, 340b, 341a, and 341b. Furthermore, the four gas nozzles 340a, 340b, 341a, and 341b can be easily configured using two return nozzles.

[0162] In this embodiment, the flow rate of gas injected toward the periphery of the wafer 200 by the four gas nozzles 340a, 340b, 341a, and 341b arranged along the circumferential direction of the cylindrical portion is greater than the flow rate of gas injected toward the center C1 of the wafer 200, thereby reducing the area where the flow of the source gas is slow around the wafer 200. This further improves the uniformity of the flow of the source gas on the surface of the wafer 200.

[0163] In this embodiment, each of the four gas nozzles 340a, 340b, 341a, and 341b has three or more injection holes 234 arranged in a plane parallel to the surface of the wafer 200 along the circumferential direction of the cylindrical portion.

[0164] Since the source gas is radially injected from three or more injection holes 234, the region where the flow of the source gas decreases around the wafer 200 is reduced, thereby further improving the uniformity of the flow of the source gas on the surface of the wafer 200.

[0165] Furthermore, in this embodiment, the four gas nozzles 340a, 340b, 341a, and 341b and the two sub-exhaust slits 238 are arranged symmetrically with respect to the imaginary plane A. This further improves the uniformity of the flow of the source gas over the surface of the wafer 200.

[0166] In this embodiment, a plurality of wafers 200 are arranged inside the cylindrical portion along the axial direction of the cylindrical portion. Four gas nozzles 340a, 340b, 341a, and 341b are arranged along the circumferential direction of the cylindrical portion and are configured to be able to supply the same source gas. Each of the four gas nozzles 340a, 340b, 341a, and 341b has an outgoing pipe and a returning pipe through which the source gas flows, and the four gas nozzles 340a, 340b, 341a, and 341b are formed by two return nozzles that inject the same source gas by communicating the upper ends of the outgoing pipe and the returning pipe.

[0167] The return pipes of the two return nozzles 340, 341 are adjacent to each other and the outward pipes are spaced apart. Each of the outward and return pipes of the two return nozzles 340, 341 has three or more rows of injection holes 234 extending along the longitudinal direction of the return nozzle. The injection holes 234 inject the source gas radially in a plan view.

[0168] By arranging the outgoing pipe with a relatively high internal pressure outside the center C1 of the wafer 200, a large amount of gas can be supplied to the outer periphery of the wafer 200, where the flow rate and gas concentration tend to be insufficient, during radial injection. This makes it possible to suppress the occurrence of a backflow of the source gas.

[0169] In this embodiment, tanks 322b and 322c are provided, which are connected to the four gas nozzles 340a, 340b, 341a, and 341b, store source gas alone without being mixed with a carrier gas, and supply the stored source gas in pulses to the four gas nozzles 340a, 340b, 341a, and 341b almost simultaneously. The total maximum instantaneous flow rate of the source gas injected in pulses from the four gas nozzles 340a, 340b, 341a, and 341b is 5 slm or more.

[0170] Here, when flash supply is performed, if the total instantaneous maximum flow rate of the source gases is small, the film-forming gas may be subjected to sufficient heat, which may cause the gas to change in quality. On the other hand, when gas is supplied at a large flow rate, fresh gas can be supplied to the wafer 200 without being subjected to much heat. Therefore, this embodiment, in which flash supply of source gases at 5 slm or more is performed, is advantageous in that the quality of the formed film can be further improved.

[0171] Furthermore, in this embodiment, the diameter R1 of the injection hole 234 that injects the source gas from the center C1 of the wafer 200 outward among the three or more injection holes 234 can be larger than the diameters R2 of the other injection holes 234. This makes the flow rate of the exhausted source gas more uniform, thereby improving the inter-surface uniformity of the film on the surfaces of the multiple wafers 200.

[0172] Furthermore, in this embodiment, a space is formed between the wafer 200 and one of the three or more injection holes 234 that injects the source gas toward the outermost side of the wafer 200 in a plan view, allowing the source gas to travel straight along the injection direction. That is, no other structures are provided as obstacles that hinder the flow of the source gas before it reaches the wafer 200. Since the flow rate of the exhausted source gas is made more uniform, the inter-surface uniformity of the film on the surfaces of the multiple wafers 200 is improved.

[0173] In this embodiment, the reaction tube 203 further includes an outer tube 14 that surrounds the cylindrical portion to form an exhaust space S between the outer tube 14 and the cylindrical portion. The outer tube 14 has an exhaust port 230 and a pair of sub-exhaust ports (not shown) that communicate the exhaust space S with the outside of the reaction tube 203. Therefore, the source gas passes through the exhaust space and is exhausted to the outside from the exhaust port 230 and the pair of sub-exhaust ports, thereby reducing the area around the wafers 200 where the flow of the source gas is reduced. This further improves the uniformity of the flow of the source gas over the surface of the wafers 200.

[0174] In this embodiment, the opening width of one main exhaust slit 236 along the circumferential direction of the cylindrical portion narrows from the side opposite the exhaust port 230 toward the exhaust port 230 along the axial direction of the cylindrical portion. The opening width of each of the two sub-exhaust slits 238 along the circumferential direction of the cylindrical portion narrows from the side opposite each of the pair of sub-exhaust ports toward the pair of sub-exhaust ports along the axial direction of the cylindrical portion. This makes the flow rate of the source gas being exhausted more uniform among the wafers 200 stacked in multiple stages along the axial direction, thereby improving the inter-surface uniformity of the film on the surfaces of the multiple wafers 200.

[0175] Furthermore, in the sixth modified example, fins 250 are provided on parts of the side walls that form the one main exhaust slit 236 and the two sub-exhaust slits 238 of the cylindrical portion. The fins 250 protrude from the side walls toward the outer tube 14, and the protruding length decreases along the axial direction of the cylindrical portion from the side opposite the main exhaust port and the pair of sub-exhaust ports toward the main exhaust port and the pair of sub-exhaust ports. In other words, the distance between the inner tube and the outer tube in the exhaust space becomes shorter in plan view toward the main exhaust port and the pair of sub-exhaust ports along the up-down direction H.

[0176] Here, consider a case where the distance between the inner pipe and the outer pipe in the exhaust space is substantially constant in plan view toward the main exhaust port and the pair of sub-exhaust ports without providing fins 250. When the distance between the inner pipe and the outer pipe is substantially constant, the flow rate of the source gas exhausted from the portion of one main exhaust slit 236 closer to the main exhaust port is greater than the flow rate of the source gas exhausted from the portion farther from the main exhaust port.

[0177] Similarly, the flow rate of the source gas exhausted from the portion of the two sub-exhaust slits 238 closer to the sub-exhaust port is greater than the flow rate of the source gas exhausted from the portion farther from the sub-exhaust port. That is, the difference in exhaust rate between the top and bottom of each of the one main exhaust slit 236 and the two sub-exhaust slits 238 becomes greater. As a result, the unevenness in the flow rate of the source gas exhausted becomes greater among the wafers 200 stacked in multiple stages along the axial direction.

[0178] On the other hand, in the sixth modification, the fins 250 suppress the difference between the flow rate of the source gas exhausted from the bottom side near the main exhaust port and the sub-exhaust port and the flow rate of the source gas exhausted from the top side so as to be small. Therefore, the flow rate of the source gas exhausted is equalized among the wafers 200 stacked in multiple stages along the axial direction. As a result, the inter-surface uniformity of the film between the surfaces of the multiple wafers 200 is improved. Furthermore, there is no need to process the sidewall of the cylindrical portion so that the opening width of the slit narrows from the opposite side of the exhaust port toward the exhaust port along the axial direction.

[0179] Furthermore, in the seventh modification, a main exhaust buffer 232a and two sub-exhaust buffers 232b are provided, each of which sends the source gas to the outside, thereby facilitating the exhaust of the source gas to the outside.

[0180] In addition, in this embodiment, the first injection direction F1, which is the injection direction of the injection hole 234 of the return nozzle's outward pipe that is closest to the return pipe, and the second injection direction F2, which is the injection direction of the injection hole 234 of the return pipe that is closest to the outward pipe, intersect outside the wafer 200 or within the supply buffer 222.

[0181] Therefore, the source gas injected along the first injection direction and the source gas injected along the second injection direction F2 collide at a position away from the wafer 200. As a result, the source gas with a uniform concentration due to the collision can be supplied to the wafer 200. If the intersection point FX is outside the supply buffer 222 and close to the wafer 200, the collision position of the source gases is too close to the wafer 200, making it difficult to supply the source gas with a uniform concentration to the entire surface of the wafer 200. Furthermore, if the intersection point FX is located outside the range of a distance of 3r from the center C2 of the outward pipe and a distance of 3r from the center C2 of the return pipe, the distance between the collision position of the source gases and the wafer 200 becomes short. As a result, it is difficult to supply the source gas with a uniform concentration to the entire surface of the wafer 200.

[0182] In this embodiment, the supply buffer 222 is divided into three sections along the circumferential direction of the cylindrical portion by the third partition 18c and the fourth partition 18d. Among the divided sections of the supply buffer 222, the central section 222b is provided with return nozzles 340 and 341, which are provided as four gas nozzles 340a, 340b, 341a, and 341b, and gas nozzles 342a and 342c are provided on both sides of the central section to supply assist gas and reactant gas. The assist gas from the gas nozzle 342a and the like makes it easy to adjust the in-plane or inter-plane uniformity of the source gas concentration.

[0183] In this embodiment, the counter nozzle 343 that supplies the assist gas is provided as the third injector at a position where, in a plan view, the angle between the imaginary plane A and a second imaginary line L2 that connects the injection direction of the third injector and the center C1 of the wafer 200 is an obtuse angle. By mixing the assist gas from the counter nozzle 343 as the third injector with the raw material gas, it becomes easier to further adjust the uniformity of the concentration of the raw material gas.

[0184] When none of the four gas nozzles 340a, 340b, 341a, and 341b serving as the first injectors are used, 5 slm to 10 slm of assist gas is required per nozzle, such as gas nozzle 342a. On the other hand, when all of the first injectors are used, the amount of N2 used as assist gas per nozzle, such as gas nozzle 342a and counter-nozzle 343, can be reduced to about 1 slm. Furthermore, the amount of pure N2 (i.e., high-purity N2) used in the entire substrate processing can be reduced by 10% to 20%.

[0185] In this specification, when a numerical range is expressed, such as "3 slm to 4 slm," it means that the lower limit and upper limit are included in the range. For example, "3 slm to 4 slm" means "3 slm or more and 4 slm or less." The same applies to other numerical ranges.

[0186] Furthermore, in this embodiment, the central angle θ of the sector formed by the imaginary arc connecting both circumferential ends of the cylindrical portion of the supply buffer 222 and the center C1 of the wafer 200 is less than 30 degrees. If the central angle θ is 30 degrees or more, the circumferential width of the cylindrical portion of the supply buffer 222 becomes wider, resulting in an increase in the overall size of the supply buffer 222. That is, in this embodiment, the circumferential width of the cylindrical portion of the supply buffer 222 can be narrower than when the central angle θ is 30 degrees or more. This allows the overall size of the supply buffer 222 to be reduced.

[0187] Furthermore, in the substrate processing method using the substrate processing apparatus 10 according to this embodiment, the uniformity of the flow of the source gas on the surface of the wafer 200 can be improved.

[0188] Furthermore, in the semiconductor device manufacturing method including the substrate processing method according to this embodiment, the uniformity of the flow of the raw material gas on the surface of the wafer 200 can be improved, so that a semiconductor device can be manufactured in which the in-plane uniformity and step coverage of the raw material gas adsorbed on the surface of the wafer 200 are improved.

[0189] In particular, in the manufacture of semiconductor devices, such as 3D NAND flash memories, relatively deep pinholes may be formed on the surface of the wafer 200. The deeper the pinholes, the greater the surface area of ​​the wafer 200, and therefore the amount of source gas required for the film formation process increases in accordance with the surface area. For this reason, this embodiment, which improves the uniformity of the source gas flow, can be advantageously applied to film formation processes in the manufacturing process of semiconductor devices in which relatively deep holes are formed on the surface.

[0190] <Other Aspects of the Present Disclosure> Although the present disclosure has been described based on the aspects of the disclosed embodiments, the descriptions and drawings forming part of this disclosure should not be understood to limit the present disclosure. The present disclosure is not limited to the above aspects, and various modifications can be made without departing from the spirit of the present disclosure.

[0191] For example, in the above-described embodiment, an example of forming a film using a batch-type substrate processing apparatus that processes multiple substrates at a time has been described. The present disclosure is not limited to the above-described embodiment, and can be suitably applied to, for example, a case where a film is formed using a single-wafer-type substrate processing apparatus that processes one or several substrates at a time.

[0192] In the above-described embodiment, a film is formed using a substrate processing apparatus having a hot-wall type processing furnace. However, the present disclosure is not limited to the above-described embodiment and can be suitably applied to a case where a film is formed using a substrate processing apparatus having a cold-wall type processing furnace.

[0193] When using these substrate processing apparatuses, each process can be performed using the same processing procedures and conditions as in the above-described embodiments and modifications, and the same effects as in the above-described embodiments and modifications can be obtained.

[0194] The present disclosure may also be configured by partially combining the configurations included in the above-disclosed multiple embodiments, modifications, and aspects. In the present disclosure configured by combining the configurations, the processing procedures and processing conditions executed may be configured similarly to the processing procedures and processing conditions described in the aspects of the present embodiment, for example.

[0195] The present disclosure includes various embodiments not described above, and the technical scope of the present disclosure is defined only by the invention-specifying matters in the scope of the claims that are appropriate from the above description.

[0196] The disclosure of Japanese Patent Application No. 2022-017389, filed on February 7, 2022, is incorporated herein by reference in its entirety. In addition, all documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference. [Explanation of symbols]

[0197] 10. Substrate processing equipment 200 wafers (substrates) 203 Reaction tube (processing tube) 222 Supply Buffer 236 Main exhaust slit (exhaust section) 238 Sub-exhaust slit (exhaust section) 340a gas nozzle (first injector) 340b Gas nozzle (first injector) 341a Gas nozzle (first injector) 341b Gas nozzle (first injector) A Virtual Surface

Claims

1. (a) a process tube having a cylindrical portion whose upper portion is covered and which accommodates a substrate therein; (b) a supply buffer provided on a side wall of the cylindrical portion and protruding outward from the side wall; (c) a first injection device provided inside the supply buffer and extending along the axis of the cylindrical portion; (d) a plurality of exhaust sections formed on the side wall of the cylindrical section and configured to exhaust a source gas, the plurality of exhaust sections each having a pair of openings sandwiching an imaginary plane that is set to pass through the circumferential center of the cylindrical section and the axis of the cylindrical section at the boundary between the supply buffer and the cylindrical section in a plan view; Equipped with the plurality of exhaust sections include one main exhaust section formed on the side wall of the cylindrical section on the opposite side of the supply buffer with respect to the center of the substrate; the pair of exhaust units are two sub-exhaust units that are disposed at the same height as the main exhaust unit and spaced apart from the main exhaust unit, and that sandwich the main exhaust unit; In a plan view, an angle between each first imaginary line connecting a center of the sub-exhaust section and a center of the substrate and the imaginary plane is an obtuse angle; The substrate processing apparatus, wherein the width of each of the two auxiliary exhaust sections in the circumferential direction of the cylindrical section is smaller than the width of the main exhaust section.

2. a plurality of the first injectors are arranged along a circumferential direction of the cylindrical portion and are configured to be able to supply the same source gas; each of the plurality of first injection devices has an outward pipe and a return pipe through which the source gas flows, an upper end of the outward pipe and an upper end of the return pipe are in communication with each other, and the outward pipe and the return pipe are return nozzles having injection holes for injecting the same source gas; The substrate processing apparatus according to claim 1 .

3. four first injectors are formed by two return nozzles; The substrate processing apparatus according to claim 2 .

4. the first injection device has three or more injection holes arranged in a plane parallel to the surface of the substrate and along a circumferential direction of the cylindrical portion; The substrate processing apparatus according to claim 1 .

5. The first injection device and the pair of exhaust sections are configured symmetrically with respect to the imaginary plane. The substrate processing apparatus according to claim 1 .

6. (a) a processing tube having a cylindrical portion whose upper portion is covered and which accommodates a substrate inside; (b) a supply buffer provided on a side wall of the cylindrical portion and protruding outward from the side wall; (c) a first injection device provided inside the supply buffer and extending along the axis of the cylindrical portion; (d) a plurality of exhaust sections formed on the side wall of the cylindrical section and configured to exhaust a source gas, the plurality of exhaust sections each having a pair of openings sandwiching an imaginary plane that is set to pass through the circumferential center of the cylindrical section and the axis of the cylindrical section at the boundary between the supply buffer and the cylindrical section in a plan view; Equipped with a plurality of the substrates are arranged inside the cylindrical portion along the axial direction of the cylindrical portion; a plurality of the first injectors are arranged along a circumferential direction of the cylindrical portion and are configured to be able to supply the same source gas; each of the plurality of first injection devices has an outward pipe and a return pipe through which the source gas flows, an upper end of the outward pipe and an upper end of the return pipe are in communication with each other, and the outward pipe and the return pipe have two return nozzles each having an injection hole for injecting the same source gas, so that there are four of the first injection devices; The two return nozzles are arranged such that the return pipes are adjacent to each other and the outward pipes are spaced apart from each other, the outward pipe and the return pipe of the two return nozzles each have three or more rows of injection holes extending along the longitudinal direction of the return nozzle, the injection holes inject the source gas radially in a plan view; Substrate processing equipment.

7. a plurality of the first injectors are arranged along a circumferential direction of the cylindrical portion and are configured to be able to supply the same source gas; a tank connected to the plurality of first injectors, storing the source gas alone without being mixed with a carrier gas, and supplying the stored source gas to the plurality of first injectors in a pulsed manner almost simultaneously; a total maximum instantaneous flow rate of the source gas injected in a pulsed manner from each of the plurality of first injectors is 5 slm or more; The substrate processing apparatus according to claim 1 .

8. Among the three or more injection holes, the diameter of the injection hole that injects the source gas from the center of the substrate toward the outermost side is larger than the diameters of the other injection holes. The substrate processing apparatus according to claim 4 .

9. a space that allows the source gas to travel straight along the injection direction is formed between the substrate and one of the three or more injection holes that injects the source gas toward the outermost side of the substrate in a plan view, without any structure being provided between the substrate and the one injection hole. The substrate processing apparatus according to claim 4 .

10. 2. The substrate processing apparatus of claim 1, wherein the processing tube further comprises an outer tube surrounding the cylindrical portion to form an exhaust space between the cylindrical portion and the outer tube, the outer tube having an exhaust port communicating the exhaust space with the outside of the processing tube.

11. the processing tube further includes an outer tube surrounding the cylindrical portion to form an exhaust space between the outer tube and the cylindrical portion, the outer tube having an exhaust port communicating the exhaust space with the outside of the processing tube; an opening width of each of the main exhaust section and the pair of auxiliary exhaust sections along the circumferential direction of the cylindrical section narrows from an opposite side to the exhaust port toward the exhaust port along the axial direction of the cylindrical section; The substrate processing apparatus according to claim 1 .

12. The processing tube includes an outer tube that surrounds the cylindrical portion to form an exhaust space between the outer tube and the cylindrical portion, and that has an exhaust port that communicates the exhaust space with the outside of the processing tube; an exhaust flow rate adjusting section that protrudes from a part of the side wall that forms each of the main exhaust section and the pair of sub-exhaust sections in the cylindrical section toward the outer pipe, the protruding length decreasing from the side opposite the exhaust port toward the exhaust port along the axial direction of the cylindrical section; The substrate processing apparatus of claim 1 , further comprising:

13. The apparatus further includes a main exhaust device and two sub-exhaust devices each for sending the source gas to the outside. The substrate processing apparatus according to claim 1 .

14. (a) a process tube having a cylindrical portion whose upper portion is covered and which accommodates a substrate inside; (b) a supply buffer provided on a side wall of the cylindrical portion and protruding outward from the side wall; (c) a first injection device provided inside the supply buffer and extending along the axis of the cylindrical portion; (d) a plurality of exhaust sections formed on the side wall of the cylindrical section and configured to exhaust a source gas, the plurality of exhaust sections each having a pair of openings sandwiching an imaginary plane that is set to pass through the circumferential center of the cylindrical section and the axis of the cylindrical section at the boundary between the supply buffer and the cylindrical section in a plan view; Equipped with a plurality of the first injectors are arranged along a circumferential direction of the cylindrical portion and are configured to be able to supply the same source gas; each of the plurality of first injection devices has an outward pipe and a return pipe through which the source gas flows, an upper end of the outward pipe and an upper end of the return pipe are in communication with each other, and the outward pipe and the return pipe are return nozzles having injection holes for injecting the same source gas; a first injection direction, which is closest to the return pipe among the injection directions of the injection holes of the outward pipe of the return nozzle, and a second injection direction, which is closest to the outward pipe among the injection directions of the injection holes of the return pipe, intersect outside the substrate; Substrate processing equipment.

15. (a) a process tube having a cylindrical portion whose upper portion is covered and which accommodates a substrate therein; (b) a supply buffer provided on a side wall of the cylindrical portion and protruding outward from the side wall; (c) a first injection device provided inside the supply buffer and extending along the axis of the cylindrical portion; (d) a plurality of exhaust sections formed on the side wall of the cylindrical section and configured to exhaust a source gas, the plurality of exhaust sections each having a pair of openings sandwiching an imaginary plane that is set to pass through the circumferential center of the cylindrical section and the axis of the cylindrical section at the boundary between the supply buffer and the cylindrical section in a plan view; Equipped with the supply buffer is divided into three by partition walls along the circumferential direction of the cylindrical portion, a return nozzle provided as the first injection device in a central portion of the divided portions of the supply buffer; second injection devices provided on both sides of the central portion for supplying assist gas; The substrate processing apparatus further comprises:

16. a third injector that supplies an assist gas, the third injector being provided as a counter nozzle at a position where, in a plan view, an angle between a second imaginary line connecting the injection direction of the third injector and the center of the substrate and the imaginary plane is an obtuse angle; The substrate processing apparatus of claim 6 , further comprising:

17. a central angle of a sector formed by an imaginary arc connecting both ends of the cylindrical portion of the supply buffer in the circumferential direction and the center of the substrate is less than 30 degrees; 16. The substrate processing apparatus according to claim 1, 6, 14, or 15.

18. (A) placing a substrate inside a cylindrical portion of a process tube having a covered top; (B) injecting a source gas toward the substrate using a nozzle provided inside a supply buffer provided on a side wall of the cylindrical portion so as to protrude outward from the side wall and extending along the axis of the cylindrical portion; (C) A plurality of exhaust sections formed on a side wall of the cylindrical section and exhausting the source gas, the plurality of exhaust sections including a pair of exhaust sections that have openings sandwiching an imaginary plane that is set to pass through the circumferential center of the cylindrical section and the axis of the cylindrical section at the boundary between the supply buffer and the cylindrical section in a plan view, and one main exhaust section formed on the side wall of the cylindrical section on the opposite side from the supply buffer with respect to the center of the substrate, the pair of exhaust units are two sub-exhaust units that are disposed at the same height as the main exhaust unit and spaced apart from the main exhaust unit, and that sandwich the main exhaust unit; In a plan view, an angle between each first imaginary line connecting a center of the sub-exhaust section and a center of the substrate and the imaginary plane is an obtuse angle; the width of each of the two auxiliary exhaust sections in the circumferential direction of the cylindrical section is smaller than the width of the main exhaust section, and the injected source gas is exhausted to the outside of the cylindrical section using a plurality of exhaust sections. Substrate processing method.

19. (α) placing a substrate inside a cylindrical portion of a process tube having a covered top; (β) spraying a source gas toward the substrate using a nozzle provided inside a supply buffer provided on a side wall of the cylindrical portion so as to protrude outward from the side wall and extending along the axis of the cylindrical portion; (γ) A plurality of exhaust sections formed on a side wall of the cylindrical section and exhausting the source gas, the plurality of exhaust sections including a pair of exhaust sections having openings sandwiching an imaginary plane set to pass through the circumferential center of the cylindrical section and the axis of the cylindrical section at the boundary between the supply buffer and the cylindrical section in a plan view, and one main exhaust section formed on the side wall of the cylindrical section on the opposite side of the supply buffer with respect to the center of the substrate, the pair of exhaust units are two sub-exhaust units that are disposed at the same height as the main exhaust unit and spaced apart from the main exhaust unit, and that sandwich the main exhaust unit; In a plan view, an angle between each first imaginary line connecting a center of the sub-exhaust section and a center of the substrate and the imaginary plane is an obtuse angle; a step of exhausting the injected source gas to the outside of the cylindrical portion using a plurality of exhaust sections, each of which has a width smaller than a width of the main exhaust section in a circumferential direction of the cylindrical portion; A method for manufacturing a semiconductor device, comprising:

Images