Substrate processing apparatus, substrate processing method, method for manufacturing semiconductor device, and recording medium

Abstract

A substrate processing apparatus has: an outer pipe of a cylindrical shape whose upper end is blocked and whose lower end is opened; an inner pipe provided inside the outer pipe, formed into a cylindrical shape whose upper end is blocked and whose lower end is opened, and capable of processing a substrate inside; a manifold of a cylindrical shape connected to the lower end of the outer pipe and the lower end of the inner pipe and communicating with a processing chamber of the inner pipe, provided with an exhaust space isolated from an annular space between the inner pipe and the outer pipe; a processing gas nozzle that supplies a processing gas for processing a substrate to the inside of the inner pipe; a purge gas nozzle that supplies a purge gas to the annular space; and a flow conductance variable portion provided between the annular space and the exhaust space and allowing gas to pass between the annular space and the exhaust space.

Description

Technical Field

[0001] This invention relates to a substrate processing apparatus, a substrate processing method, a method for manufacturing a semiconductor device, and a recording medium. Background Technology

[0002] In the manufacturing method of semiconductor integrated circuit devices (hereinafter referred to as ICs), for polycrystalline or single-crystal silicon or silicon-germanium films formed on silicon wafers, a batch vertical hot-wall CVD film forming apparatus (hereinafter referred to as a substrate processing apparatus) is used, for example.

[0003] This substrate processing apparatus includes an outer tube and an inner tube disposed inside the outer tube. By moving a silicon wafer into the inner tube, and supplying processing gas into the inner tube while heating the inner tube with a heater, a film is formed on the silicon wafer (see, for example, Japanese Patent Application Laid-Open No. 2003-203868 and Japanese Patent Application Laid-Open No. 2006-5198). Summary of the Invention

[0004] However, in such a substrate processing apparatus, if the processing gas flows into the space between the inner tube and the outer tube, it will cause a film of reaction products (such as a silicon or silicon-germanium deposited film) to be generated on the inner surface of the outer tube facing the space, and removing the reaction products from the outer tube is troublesome.

[0005] The purpose of this invention is to provide a technique for suppressing the formation of a film containing reaction products on the inner surface of an outer tube.

[0006] According to one aspect of the present invention, a technique is provided, for example, comprising: a cylindrical outer tube, the upper end of which is sealed and the lower end is open; an inner tube disposed inside the outer tube, formed as a cylinder with the upper end sealed and the lower end open, capable of processing a substrate inside; a cylindrical manifold disposed below the outer and inner tubes, communicating with the internal space of the inner tube, and having an exhaust space isolated relative to the annular space between the inner and outer tubes; a processing gas nozzle that supplies processing gas for substrate processing to the interior of the inner tube; a purge gas nozzle that supplies purge gas to the annular space; and a variable flow section disposed in a partition between the annular space and the exhaust space, allowing gas to pass through between the annular space and the exhaust space, and allowing the flow of gas to be variable.

[0007] Invention Effects

[0008] As explained above, the substrate processing apparatus and substrate processing method according to the present invention can suppress the formation of a film of reaction products on the inner surface of the outer tube. Attached Figure Description

[0009] Figure 1This is a longitudinal sectional view of a substrate processing apparatus according to one embodiment of the present invention.

[0010] Figure 2 This is a horizontal cross-sectional view of a substrate processing apparatus according to one embodiment of the present invention.

[0011] Figure 3 This is a perspective view of the flow-conducting variable section of a substrate processing apparatus according to one embodiment of the present invention.

[0012] Figure 4 It is a three-dimensional diagram showing the connection state between the inner tube fitting ring and the inner tube support.

[0013] Figure 5 This is a perspective view showing the lower end of the inner tube with the inner tube installed on the inward-facing flange.

[0014] Figure 6A This is a cross-sectional view along the axis of a fastening screw with a vent hole.

[0015] Figure 6B This is a cross-sectional view along the axis of a typical fastening screw. Detailed Implementation

[0016] use Figure 1 Figure 6 illustrates a substrate processing apparatus 10 according to one embodiment of the present invention. Furthermore, the figures used in the following description are schematic, and the dimensional relationships and ratios of the elements shown may not necessarily correspond to actual dimensions. Additionally, the dimensional relationships and ratios of elements may not necessarily be consistent across different figures.

[0017] exist Figure 1 The schematic structure of the substrate processing apparatus 10 of the present invention is shown in the cross-sectional view. The substrate processing apparatus 10 is configured, for example, as a vertical CVD film deposition apparatus (batch vertical hot-wall CVD film deposition apparatus) used in the manufacture of ICs and the like to deposit polycrystalline silicon films on silicon wafers (hereinafter referred to as substrates).

[0018] Figure 1 The substrate processing apparatus 10 shown has a longitudinally shaped outer tube 11 arranged vertically along its central axis, and an inner tube 12 is coaxially housed inside the outer tube 11. Furthermore, an annular space 18 is provided between the outer tube 11 and the inner tube 12.

[0019] In this embodiment, the outer tube 11 is made of quartz and is formed into a cylindrical shape with a sealed top. The inner tube 12 is made of silicon carbide (SiC) and is formed into a cylindrical shape with a sealed top and a diameter smaller than that of the outer tube 11. The outer tube 11 is a pressure vessel and needs to be sealed using the sealing material 33, which will be described later as the first sealing material. Furthermore, silicon carbide, with its high thermal conductivity, easily transfers heat from the furnace to the sealing material 33, exposing the sealing material 33 to high temperatures, making it difficult to use in the outer tube 11. The inner tube 12 has a thinner wall thickness compared to the outer tube 11 and may not necessarily have the strength to withstand the pressure difference between atmospheric pressure and vacuum.

[0020] Furthermore, the coefficient of linear expansion of silicon carbide (SiC) is known to be, for example, 4.2 × 10⁻⁶ for conventionally formed products based on reaction sintering using 4H-SiC powder as the main raw material. -6 / K, the coefficient of linear expansion of the polycrystalline silicon film, described later, is 3.9 × 10⁻⁶. -6 / K, relative to the coefficient of linear expansion of polycrystalline silicon, the coefficient of linear expansion of silicon carbide (SiC) is +7.6%. Furthermore, the coefficient of linear expansion of quartz (SiO2) is 0.5 × 10⁻⁶. -6 / K.

[0021] The internal space of the inner tube 12 is configured as a processing chamber 13 for transporting multiple substrates 1 stacked in the boat 25. In addition, the lower opening of the inner tube 12 forms a furnace opening 14 for loading and unloading the boat 25.

[0022] The outer tube 11 is fixed to the upper part of the manifold 16, which is a short cylindrical shape and is mounted on the housing 2 of the substrate processing device 10.

[0023] The manifold 16 has an upper flange 16A that protrudes radially outward at its upper end and a lower flange 16B that protrudes radially outward at its lower end. The manifold 16 also has an inwardly projecting flange (rib) 17 that protrudes radially inward and is formed in a ring shape, serving as a partition wall. Furthermore, the inwardly projecting flange 17 is ring-shaped.

[0024] Inside the manifold 16, the space between the inward flange 17 and the upper surface of the housing 2 is designated as the exhaust space ES.

[0025] The lower end of the outer tube 11 is supported on the upper flange 16A of the manifold 16 via a sealing material 33. The lower flange 16B of the manifold 16 is supported on the upper surface of the housing 2 via a sealing material 34, which serves as a second sealing material.

[0026] On the outer wall of the manifold 16, an exhaust pipe 19, which serves as an exhaust port and communicates with the exhaust space ES, is provided at a position lower than the inward flange 17. An exhaust device (not shown) for exhausting gas inside the exhaust space ES is connected to the exhaust pipe 19.

[0027] like Figure 1 , Figures 3-5 As shown, a flange (lip) 12A protruding radially outward is integrally formed at the lower end of the inner tube 12. The outer diameter of the flange 12A is smaller than the inner diameter of the inward flange 17, allowing it to pass through the manifold 16 axially (vertically).

[0028] An annular inner tube support 35 is disposed on the lower side of the flange 12A, and an annular sealing flange 36, serving as a mounting component, is disposed on the lower side of the inner tube support 35. Additionally, an annular inner tube fitting ring 37 is disposed on the upper side of the flange 12A.

[0029] Although the inner tube support 35 is ring-shaped, it has a plurality of protrusions 35A spaced circumferentially on its outer periphery, protruding radially outward. The outer diameter of the inner tube support 35, excluding the protrusions 35A, is smaller than the inner diameter of the inward flange 17.

[0030] Furthermore, although the inner tube fitting ring 37 is ring-shaped, a protrusion 37A protruding radially outward is formed on its outer periphery at a position opposite to the protrusion 35A of the inner tube support 35. The outer diameter of the inner tube fitting ring 37, excluding the protrusion 37A, is smaller than the inner diameter of the inward flange 17.

[0031] Multiple notches 17A are formed on the inner periphery of the inward flange 17. These multiple notches 17A are used to allow the protrusions 35A of the inner tube support 35 and the protrusions 37A of the inner tube fitting ring 37 to pass through in the axial direction (up and down direction).

[0032] Therefore, when the protrusion 37A of the inner tube fitting ring 37 and the protrusion 35A of the inner tube support member 35 are aligned with the notch 17A of the inward flange 17, the inner tube fitting ring 37 and the inner tube support member 35 can pass through the inward flange 17 in the axial direction (up and down direction).

[0033] like Figure 4 As shown, with the flange 12A of the inner tube 12 sandwiched between the inner tube fitting ring 37 and the inner tube support member 35, the inner tube fitting ring 37 and the inner tube support member 35 are connected to each other by a plurality of screws 38. Thus, the inner tube fitting ring 37 and the inner tube support member 35 are fixed to the flange 12A of the inner tube 12. Furthermore, a threaded hole 35B for screws 38 to engage is formed on the inner tube support member 35, and a hole 37B for screws 38 to pass through is formed on the inner tube fitting ring 37.

[0034] like Figure 5As shown, the sealing flange 36 is formed with a diameter larger than the inner diameter of the inward flange 17, and abuts against the lower surface of the inward flange 17. The sealing flange 36 is fixed to the inner tube support 35 by a plurality of screws 40. The inward flange 17 is held by the inner tube support 35 and the sealing flange 36, thereby the inner tube 12 is mounted on the inward flange 17. Thus, even if the pressure in the processing chamber 13 is higher than the pressure in the annular space 18, the inner tube 12 will not float or move. In addition, a threaded hole 35C for screws 40 to engage is formed on the inner tube support 35, and a hole 36B for screws 40 to pass through is formed on the sealing flange 36.

[0035] In addition, the outer diameters of the inner tube fitting ring 37, the inner tube 12, the inner tube support 35, and the sealing flange 36 are each set to be smaller than the inner diameter of the manifold 16.

[0036] like Figure 3 As shown, a plurality of threaded holes 41 (eight in this embodiment) are formed circumferentially spaced on the sealing flange 36, and a plurality of threaded holes 41 (eight in this embodiment) are formed on the inward flange 17 at the same intervals as the threaded holes 41. (Refer to...) Figure 2 ) Through hole 42.

[0037] Furthermore, after aligning the protrusions 37A of the inner tube fitting ring 37 and the inner tube support 35 with the notch 17A of the inward flange 17, and passing the inner tube 12, inner tube fitting ring 37, and inner tube support 35 upward relative to the inward flange 17, the inner tube 12 is rotated, thereby aligning the threaded hole 41 of the sealing flange 36 with the through hole 42 of the inward flange 17. Additionally, with the threaded hole 41 and through hole 42 aligned, the inner tube 12 is installed on the inward flange 17 as described above.

[0038] These threaded holes 41 can be screwed in Figure 6A The fastening screw 43 shown has an internal hexagonal socket and a vent hole. Figure 6B The example shown is a common fastening screw 44 with an internal hexagonal socket. On the axis of the fastening screw 43 with a vent hole, a vent hole 43A with a diameter of, for example, 0.8 mm is formed, which allows gas to pass through.

[0039] The fastening screws 43 and 44 with vent holes are, for example, metric screws of M4 to M6.

[0040] In the substrate processing apparatus 10, a fastening screw 43 with a vent hole is screwed into at least one of the multiple threaded holes 41, and fastening screws 44 or ordinary screws are screwed into the remaining threaded holes 41. Thus, the processing chamber 13 and the annular space 18 are connected only through the vent hole 43A of the fastening screw 43 with the vent hole.

[0041] Furthermore, the variable flow guide of the present invention is constituted by multiple threaded holes 41, fastening screws 43 with vent holes, and fastening screws 44. Flow guide is the reciprocal of the gas flow resistance when gas flows from the annular space 18 to the exhaust space ES. For example, if the number of fastening screws 43 with vent holes is increased, the flow resistance decreases and the flow guide increases.

[0042] (Handling the gas nozzle)

[0043] like Figure 1 and Figure 2 As shown, multiple processing gas nozzles 21 are inserted into the side wall of the manifold 16, positioned lower than the inward flange 17. The open ends of the processing gas nozzles 21 are located at the upper end of the processing chamber 13 or on the side of the substrate 1. That is, each processing gas nozzle 21 has only one opening at its front end, with the same shape and area as the tube's cavity. This large opening will not be blocked by deposits like a pinhole opening. The multiple processing gas nozzles 21 are at different heights within the processing chamber 13. To ensure uniformity of film thickness and film quality (grain size) on the surfaces of each substrate 1, the flow rate of the raw material gas 50 discharged from each processing gas nozzle 21 is controlled. The processing gas nozzles 21 can be made of the same material as the outer tube 11 or a different material. Furthermore, the processing gas nozzle 21 is an example of the processing gas nozzle of the present invention.

[0044] A gas supply device (not shown) is connected to the processing gas nozzle 21, from which processing gases (raw material gas 50, hydrogen (H2) as a pretreatment gas, or nitrogen as a purging gas) are supplied. These gases are ejected from the open end of the processing gas nozzle 21 into the interior of the processing chamber 13. The gas introduced into the processing chamber 13 by the processing gas nozzle 21 flows down in the processing chamber 13 and is discharged to the outside through the exhaust space ES and the exhaust pipe 19.

[0045] (Purge gas nozzle)

[0046] A purge gas nozzle 20, serving as a purge gas nozzle, is inserted into the side wall of the manifold 16, with its open end positioned at the upper end of the annular space 18. A gas supply device for supplying nitrogen, an inactive gas, is connected to the purge gas nozzle 20. The nitrogen introduced into the upper end of the annular space 18 by the purge gas nozzle 20 can flow down within the annular space 18 and exit through the vent 43A of the fastening screw 43 with a vent hole to the exhaust space ES.

[0047] The gas supply device is configured by connecting the control valve 53 and the flow controller 54 in series, supplying nitrogen from the nitrogen source to the purge gas nozzle 20 at a specified mass flow rate. In addition, two pipes are branched onto the pipeline from the nitrogen source. One pipe is connected to the purge gas nozzle 20 via the gas supply device, and the other pipe is connected to the treatment gas nozzle 21 via the same gas supply device (not shown).

[0048] like Figure 1 As shown, pipes 45 and 46 pass through manifold 16.

[0049] One end of the piping 45 is disposed in the processing chamber 13, and a first pressure gauge 48 is installed on the other end of the piping 45 via an on / off valve 47. The internal pressure of the processing chamber 13 can be detected by the first pressure gauge 48. Furthermore, the on / off valve 47 can be opened as needed, such as when using the first pressure gauge 48.

[0050] Additionally, one end of the piping 46 is disposed in the annular space 18, and a second pressure gauge 52 is installed on the other end of the piping 46 via an on / off valve 51. The internal pressure of the annular space 18 can be detected by the second pressure gauge 52. Furthermore, the on / off valve 51 can be opened as needed when using the second pressure gauge 52.

[0051] Additionally, a vessel inlet / outlet 3 is provided on the housing 2 at a position opposite to the manifold 16. A sealing cover 22, which is raised and lowered by a vessel lifter (not shown), abuts against the lower surface of the housing 2 from the lower vertical direction to seal the vessel inlet / outlet 3.

[0052] The sealing cover 22 is formed into a disc shape with an outer diameter larger than the inner diameter of the vessel inlet / outlet 3. The vessel inlet / outlet chamber 4 formed by the shell 2 is raised and lowered below the outer tube 11 by the vessel lifter.

[0053] A rotating shaft 24, which is rotated by a rotating actuator 23, is arranged on the central axis of the sealing cover 22, and a boat 25 is vertically supported at the upper end of the rotating shaft 24.

[0054] The vessel 25 has a pair of end plates 26 and 27, and three retaining members 28 that are mounted between the end plates 26 and 27 and arranged vertically. On the three retaining members 28, a plurality of retaining grooves 29 are engraved along the length direction in such a way that they are equally spaced and open to each other.

[0055] The boat 25 holds multiple substrates 1 horizontally and with their centers aligned by inserting substrates 1 between the holding grooves 29 of the three holding members 28. The boat 25 can be made of the same material as the outer tube 11 or a different material.

[0056] The outer side of the outer tube 11 is completely covered by the heat insulation cover 31. On the inner side of the heat insulation cover 31, heaters 32 are arranged in concentric circles around the outer tube 11 to heat the inside of the outer tube 11.

[0057] The heat shield 31 and the heater 32 are vertically supported by a bracket 5 constructed on the housing 2. The heater 32 is divided into multiple heater sections, which are configured to cooperate with each other and be sequentially controlled independently by a temperature controller (not shown).

[0058] (Preparation)

[0059] First, the pre-processing (initial setting of substrate processing apparatus 10) before processing substrate 1 in substrate processing apparatus 10 of this embodiment will be explained.

[0060] In this substrate processing apparatus 10, when processing the substrate 1 housed in the inner tube 12 with the raw material gas 50, it is necessary to supply nitrogen gas to the annular space 18 and prevent the raw material gas 50 supplied to the inner tube 12 from flowing into the annular space 18. In addition, it is preferable to suppress the amount of nitrogen supplied to the annular space 18 in order to avoid wasting nitrogen gas supplied to the annular space 18.

[0061] Therefore, before actually processing the substrate 1, the number of mounting screws 43 with vent holes is adjusted so that the pressure in the annular space 18 becomes slightly higher than the internal pressure in the processing chamber 13, and the amount of nitrogen used (i.e. the amount discharged from the annular space 18 to the exhaust space ES of the manifold 16) is suppressed.

[0062] During the preparation phase, nitrogen gas is supplied to the processing chamber 13 from the processing gas nozzle 21 while venting is performed through an exhaust device to bring the pressure inside the processing chamber 13 to a level consistent with the actual processing conditions. Additionally, nitrogen gas is supplied to the annular space 18, and the internal pressure of the processing chamber 13 is detected by a first pressure gauge 48, while the internal pressure of the annular space 18 is detected by a second pressure gauge 52. Furthermore, during the preparation phase, it is not necessary to house the substrate 1 within the inner tube 12.

[0063] Then, by changing the number of fastening screws 43 with vent holes and confirming the detection of the internal pressure of the processing chamber 13, the internal pressure of the annular space 18, and the flow rate of nitrogen, the necessary number of fastening screws 43 with vent holes is determined in advance so that the internal pressure of the annular space 18 is slightly higher than the internal pressure of the processing chamber 13, or the gas flow rate in the vent hole 43A is above a specified level. This ensures that the differential pressure between the internal pressure of the processing chamber 13 and the internal pressure of the annular space 18 remains constant and that the amount of nitrogen used is suppressed. Furthermore, in processes where the pressure of the processing chamber 13 fluctuates significantly, it is desirable that the differential pressure be maintained at least below the pressure resistance of the inner tube. For example, if the differential pressure is kept small by allowing flow in the vent hole 43A (including temporary backflow) that accompanies pressure fluctuations, the minimum total conductance of the vent hole 43A is determined based on the volume of the annular space 18 and the maximum pressure fluctuation rate.

[0064] This pre-processing is now complete, allowing the actual processing of substrate 1 to proceed. Furthermore, this pre-processing can also be performed via desktop computing.

[0065] Furthermore, the substrate processing apparatus 10 of this embodiment is in a state in which a fastening screw 43 with a vent hole is screwed into a threaded hole 41 at the position furthest from the purge gas nozzle 20, and ordinary fastening screws 44 are screwed into other threaded holes 41.

[0066] (Functions and Effects)

[0067] Next, the function and effect of the substrate processing apparatus 10 prepared as described above will be explained in the case of forming a polycrystalline silicon film on the substrate 1.

[0068] like Figure 1 As shown, a boat 25 holding multiple substrates 1 is placed on a sealing cover 22 with the direction of the substrate 1 group being perpendicular. The substrate 1 group is pushed up by the boat lifter and moved (boat loading) from the furnace opening 14 of the inner tube 12 into the processing chamber 13, and is arranged in the processing chamber 13 while being supported by the sealing cover 22.

[0069] Next, the air inside the outer tube 11 is exhausted through the exhaust pipe 19 in such a way that the pressure inside the outer tube 11 is a specified pressure (e.g., 0.1 to 100 Pa), and the heater 32 heats the inside of the outer tube 11 to a specified temperature (e.g., about 650°C (500 to 750°C)).

[0070] Next, hydrogen (H2) gas, which is used as a pretreatment gas, is introduced into the upper part of the processing chamber 13 through the processing gas nozzle 21 at a specified flow rate (0.1 to 10 L / min). The hydrogen gas introduced into the upper part of the processing chamber 13 through the processing gas nozzle 21 flows down in the processing chamber 13 and is discharged to the outside of the substrate processing apparatus 10 through the exhaust space ES of the manifold 16 and the exhaust pipe 19.

[0071] Furthermore, during the flow of hydrogen gas down in the processing chamber 13, it comes into contact with the substrate 1 held in the boat 25, thereby performing pretreatment such as reduction on the substrate 1.

[0072] If the specified time has elapsed, for example, silane (SiH4) and 0.1% diluted boron trichloride (BCl3) as raw material gas 50 for silicon film formation are introduced from the processing gas nozzle 21 into the upper end of the processing chamber 13.

[0073] In addition, the flow rate of SiH4 gas is, for example, 0.5 to 3 L / min, and the flow rate of BCl3 gas is less than 0.02 L / min.

[0074] The raw material gas 50 introduced into the processing chamber 13 by the processing gas nozzle 21 flows down in the processing chamber 13 and is discharged to the outside of the substrate processing apparatus 10 through the exhaust space ES of the manifold 16 and the exhaust pipe 19.

[0075] Furthermore, the raw material gas 50 undergoes a thermal CVD reaction by contacting the substrate 1 held in the boat 25 during its flow down in the processing chamber 13, thereby depositing (depositioning) polycrystalline silicon on the substrate 1 to form an epitaxial silicon film.

[0076] In addition, while the raw material gas 50 is supplied to the processing chamber 13, nitrogen (N2) is supplied from the purge gas nozzle 20 to the annular space 18 between the outer pipe 11 and the inner pipe 12.

[0077] Because the internal pressure of the annular space 18 is higher than the internal pressure of the inner tube 12 and the exhaust space ES of the manifold 16 which is connected to the inner tube 12, the nitrogen supplied to the annular space 18 will be discharged into the exhaust space ES of the manifold 16 through the vent 43A of the fastening screw 43 with a vent hole.

[0078] Furthermore, the nitrogen gas heats up during its flow within the purge gas nozzle 20, approaching the temperature of the processing chamber 13 as it exits from the open end, thus suppressing temperature or film thickness unevenness caused by nitrogen. Additionally, the nitrogen gas discharged upwards from the purge gas nozzle 20 circulates from top to bottom within the annular space 18 and exits through the vent 43A of the fastening screw 43 with a vent hole, thus preventing nitrogen from stagnating within the annular space 18.

[0079] This inhibits the flow and diffusion of the raw material gas 50 supplied to the inner tube 12 into the annular space 18, thereby inhibiting the deposition of silicon film on the inner surface of the outer tube 11 facing the annular space 18 and the outer surface of the inner tube 12.

[0080] In addition, the nitrogen gas discharged into the exhaust space ES of the manifold 16, together with the raw material gas 50 flowing down inside the inner tube 12, is discharged to the outside of the substrate processing apparatus 10 through the exhaust pipe 19.

[0081] If the prescribed film-forming time has elapsed, after the introduction of the raw material gas 50 is stopped, nitrogen, as the purging gas, is introduced into the processing chamber 13 from the processing gas nozzle 21, and the raw material gas 50 in the processing chamber 13 and the exhaust space ES is discharged to the outside through the exhaust pipe 19. After the raw material gas 50 has been fully discharged, the flow path from the exhaust pipe 19 to the exhaust device is blocked, allowing the pressure inside the processing chamber 13 to return to atmospheric pressure. Furthermore, to accelerate atmospheric recovery, nitrogen can also be introduced into the processing chamber 13 or the exhaust space ES through a diffusion nozzle (Break Fill Board) not shown in the diagram.

[0082] At this time, nitrogen gas is also introduced into the annular space 18 between the outer pipe 11 and the inner pipe 12 through the purge gas nozzle 20, and the differential pressure is kept below constant. In addition, the flow and diffusion of the raw material gas 50 remaining in the exhaust space ES of the inner pipe 12 and manifold 16 into the annular space 18 are suppressed.

[0083] After the processing chamber 13 and the exhaust space ES are purged with nitrogen and restored to atmospheric pressure, the boat 25 supported by the sealing cover 22 is lowered by the boat lift and removed from the furnace opening 14 of the inner tube 12 (boat unloading).

[0084] Subsequently, by repeatedly performing the above-described process, the substrate processing apparatus 10 performs batch processing of polysilicon film deposition on the substrate 1. In the above process, polysilicon with a film thickness of 2 μm or more can be deposited on the substrate 1 each time.

[0085] During the above film formation process, the raw material gas 50 not only comes into contact with the substrate 1 during its flow down in the processing chamber 13, but also with the inner surface of the inner tube 12. Therefore, the epitaxial silicon will also accumulate on the inner surface of the inner tube 12.

[0086] Since the coefficient of linear expansion of the silicon carbide (SiC) forming the inner tube 12 is approximately the same as that of the epitaxial silicon deposited on the inner surface of the inner tube 12, the difference in expansion (dimensional change) between the inner tube 12 and the epitaxial silicon deposited on the inner surface of the inner tube 12 is small when the temperature changes. Therefore, during temperature changes (e.g., from the loading of substrate 1 to the processing of substrate 1 to the unloading of substrate 1), the mechanical stress acting on the epitaxial silicon is suppressed, and the peeling of the epitaxial silicon deposit accumulated on the inner surface of the inner tube 12 can be suppressed. For this purpose, their coefficients of linear expansion should be defined as the average coefficients of linear expansion between room temperature and processing temperature, or between the temperature of the inner tube 12 or the boat 25 during the substrate 1 loading process (which is the lowest temperature) and the processing temperature, and compared.

[0087] The coefficient of linear expansion of sintered materials such as silicon carbide varies depending on the sintering conditions, and is known to range from 3.1 to 4.4 × 10⁻⁶. -6 The coefficient of linear expansion of / K, for example in the spark plasma sintering method, is known to be approximately equal to that of Si, at 3.9 × 10⁻⁶. -6 The sintered body has a coefficient of linear expansion of approximately 1 / K. Discharge plasma sintering involves sintering nano-sized SiC ultrafine powder under pressure while simultaneously passing a pulsed high current, without the use of sintering aids. However, large-scale forming presents technical challenges. Furthermore, the coefficient of linear expansion of the sintered body can be modified by using silicon carbide as the base material and selecting known additives (binders) or additives such as ZrO2, Al2O3, SiO2, TiO2, TIC, WC, B4C, MoSi2, Si3N4, AlN, TiN, BN, TiB2, ZrB2, and LAB6. In this example, the inner tube 12, the boat 25, and the processing gas nozzle 21 can be constructed from a sintered body obtained in this way, having a coefficient of linear expansion approximately equal to that of Si.

[0088] By suppressing the peeling of the deposited film accumulated on the inner surface of the inner tube 12, the generation of particles can be prevented. Therefore, the frequency of cleaning the inner tube 12 can be reduced, downtime is reduced, and thus the operating rate of the substrate processing apparatus 10 can be improved.

[0089] For example, with conventional quartz inner tubes, it is recommended to perform wet or dry cleaning of the inner tube 12 every 10 μm of cumulative film thickness. In the case of a 2 μm deposition in a single process, cleaning is required after only five film depositions. In contrast, in an inner tube 12 formed of a material with a coefficient of linear expansion of ±8% or less relative to the deposits on the substrate surface, film deposition up to a cumulative film thickness of approximately 100 μm can be achieved without particle generation under ideal conditions. With a coefficient of linear expansion exceeding ±8%, the permissible cumulative film thickness is significantly lower than 100 μm, making long-term maintenance-free operation impossible.

[0090] Furthermore, the substrate processing apparatus 10 in this example can insert the inner tube through the opening of the manifold, and the inserted inner tube can be easily attached to and detached from the inward flange of the manifold using a mounting component. That is, the inner tube can be removed without removing the outer tube. Therefore, the operation of replacing the inner tube for cleaning is easy and quick, thereby improving the operating rate of the substrate processing apparatus.

[0091] [Other Implementation Methods]

[0092] The above describes one embodiment of the present invention, but the present invention is not limited to the above. Of course, various modifications can be made without departing from its spirit.

[0093] Furthermore, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from its spirit.

[0094] In the above embodiments, although a threaded hole 41 is formed on the sealing flange 36 of the fastening screw 43 or fastening screw 44 with a vent hole and a through hole 42 is formed on the inward flange 17, it is also possible to form a through hole 42 on the sealing flange 36 and a threaded hole 41 on the inward flange 17.

[0095] In the above embodiments, the case of forming a polycrystalline silicon film was described, but the substrate processing apparatus 10 is not limited to this, and can also be applied to the case of forming a polycrystalline silicon germanium film, etc.

[0096] For example, the process conditions for forming polycrystalline silicon germanium films are as follows.

[0097] The feed gas (flow rate shown in parentheses) is, for example, SiH4 (0.5–3 L / min), 10% diluted GeH4 (less than 3 L / min), or 0.1% diluted BCl3 (less than 0.02 L / min).

[0098] The pretreatment gas is, for example, H2 (0.1–10 L / min). The pressure of the pretreatment gas is, for example, 0.1–100 Pa. For example, the pretreatment temperature is 700–1000 °C, and the film-forming temperature is 450–700 °C.

[0099] Furthermore, the linear expansion coefficient of the polycrystalline silicon germanium attached to the inner surface of the inner tube 12 is 4.2 × 10⁻⁶. -6 / K) is also related to the coefficient of linear expansion of silicon carbide (SiC) forming the inner tube 12 (4.2×10). -6 The temperature of the inner tube 12 and the epitaxial silicon germanium attached to the inner surface of the inner tube 12 is almost the same, so when the temperature changes, the epitaxial silicon germanium attached to the inner surface of the inner tube 12 is difficult to peel off from the inner tube 12.

[0100] The substrate processing apparatus of the present invention is not limited to a vertical CVD film deposition apparatus, but can be applied to all film deposition apparatuses where the temperature of the inner wall of the processing chamber can vary.

[0101] In the above embodiments, the inner tube 12 is formed of silicon carbide (SiC), and the film deposited on the inner tube 12 is polycrystalline silicon or polycrystalline silicon germanium. However, as long as the linear expansion coefficient of the material forming the inner tube 12 is similar to the linear expansion coefficient of the material of the film deposited on the inner tube 12, the materials of the inner tube 12 and the film deposited on the inner tube 12 are not limited to the above embodiments.

[0102] In the above embodiment, the number of fastening screws 43 with vent holes is pre-adjusted as a flow-conductivity variable part so that the raw material gas 50 does not flow into the annular space 18 during the processing of the substrate 1, and the amount of nitrogen supplied to the annular space 18 is suppressed. However, it is not limited to this, as long as the structure can make the flow conduction variable. For example, the gas supply amount of the gas supply device for supplying the processing gas and the gas supply device for supplying nitrogen can be adjusted to maintain the differential pressure between the annular spaces 18 appropriately. That is, the pressure difference generated by the purge gas flowing through the vent hole 43A can be directly controlled by the flow rate of the purge gas. In addition, when the pressure of the processing chamber 13 is changed as described above by repeatedly supplying and stopping the raw material gas during the processing, the flow controller 54 can be changed into a pressure controller, and the pressure of the purge gas supplied by the pressure controller can be fed forward in conjunction with the target pressure mode of the processing chamber 13.

[0103] The first pressure gauge 48 can also detect the internal pressure of the processing chamber 13 during the processing of the substrate 1, and the second pressure gauge 52 can also detect the internal pressure of the annular space 18 during the processing of the substrate 1. For example, it can be used to monitor and record the operation of the device by detecting various pressures during the processing of the substrate 1, and to detect and stop the device when the pressure deviates from the specified range.

[0104] The following describes the intended mode of the present invention.

[0105] (Postscript 1)

[0106] A substrate processing apparatus comprising:

[0107] A cylindrical outer tube, with its upper end sealed and its lower end open;

[0108] The inner tube, which is located inside the outer tube, is formed into a cylindrical shape with the upper end sealed and the lower end open, and can process the substrate inside.

[0109] The manifold is formed in the shape of a cylinder and is located below the outer pipe and the inner pipe. It communicates with the internal space of the inner pipe and has an exhaust space that is isolated from the annular space between the inner pipe and the outer pipe.

[0110] A processing gas nozzle supplies processing gas for processing the substrate into the inner tube.

[0111] A purge gas nozzle supplies purge gas to the aforementioned annular space; and

[0112] A variable flow conductance section is provided in the partition wall between the annular space and the exhaust space, which allows gas to pass between the annular space and the exhaust space, and allows the flow conductance of the gas to be variable.

[0113] (Postscript 2)

[0114] As described in Appendix 1, the substrate processing apparatus has a mounting member at the lower end of the inner tube, which allows the inner tube to be inserted through the opening of the cylindrical manifold and can be detachably mounted on an annular inward flange formed on the inner periphery of the manifold.

[0115] (Note 3)

[0116] The substrate processing apparatus as described in Appendix 1 or 2 has:

[0117] A first pressure gauge for detecting the pressure in the aforementioned internal space; and

[0118] A second pressure gauge is used to detect the pressure in the aforementioned annular space.

[0119] (Postscript 4)

[0120] As described in any one of Appendix 1 to 3, the inner tube is formed of a material having a coefficient of linear expansion of ±8% or less relative to the coefficient of linear expansion of the deposits accumulated on the inner surface of the inner tube when the substrate is processed by the processing gas.

[0121] (Note 5)

[0122] As described in any of Appendix 1 to 4, the inner tube is formed of a material having a coefficient of linear expansion substantially equal to that of the aforementioned deposit.

[0123] (Note 6)

[0124] As described in Appendix 4, the substrate processing apparatus is made of silicon, and the inner tube is a sintered body made primarily of silicon carbide.

[0125] (Note 7)

[0126] As described in any of Appendix 1 to 4, the aforementioned flow-conducting variable portion has a plurality of threaded holes provided through the aforementioned partition portion, and at least one screw that engages with one of the plurality of threaded holes.

[0127] (Postscript 8)

[0128] As described in Appendix 2, the substrate processing apparatus includes: an upper flange located at one end of the cylindrical portion and connected to the outer tube via a first sealing material; a lower flange located at the other end of the cylindrical portion and connected to a housing supporting the outer tube via a second sealing material; and an inwardly facing flange located on the inner periphery of the cylindrical portion and supporting the inner tube.

[0129] The aforementioned flow guide variable part is provided on the aforementioned inward flange or the aforementioned mounting component.

[0130] (Note 9)

[0131] In the substrate processing apparatus described in any of Appendices 1 to 4, the exhaust space of the manifold is directly connected to the internal space of the inner tube without passing through the annular space.

[0132] The aforementioned manifold is provided with an exhaust port for discharging the gas inside the aforementioned inner tube.

[0133] (Postscript 10)

[0134] The substrate processing apparatus described in Appendix 2 performs a process of depositing a film of 2 μm or more on the substrate housed inside the inner tube.

[0135] (Postscript 11)

[0136] A substrate processing method using the substrate processing apparatus described in Appendix 1, the substrate processing method comprising the following steps:

[0137] In the substrate processing step, processing gas is supplied to the inner tube on which the substrate is disposed to process the substrate, and purge gas is supplied to the annular space. The processing gas supplied to the inner tube is discharged to the outside of the manifold through the exhaust space, and the purge gas in the annular space is discharged to the outside of the manifold through the variable flow section and the exhaust space; and

[0138] In the exhaust process, after the substrate processing process is completed, purge gas is supplied from the processing gas nozzle to the internal space and from the purge gas nozzle to the annular space, so that the processing gas in the internal space is discharged to the outside of the manifold through the exhaust space.

[0139] (Postscript 12)

[0140] A program, using the substrate processing apparatus described in Appendix 1, causes a computer included in the substrate processing apparatus to perform a step of processing the substrate, which is performed through the following steps:

[0141] In the substrate processing step, processing gas is supplied to the inner tube on which the substrate is disposed to process the substrate, and purge gas is supplied to the annular space. The processing gas supplied to the inner tube is discharged to the outside of the manifold through the exhaust space, and the purge gas in the annular space is discharged to the outside of the manifold through the variable flow section and the exhaust space; and

[0142] In the exhaust step, after the substrate processing step is completed, purge gas is supplied from the processing gas nozzle to the internal space and from the purge gas nozzle to the annular space, so that the processing gas in the internal space is discharged to the outside of the manifold through the exhaust space.

Claims

1. A substrate processing apparatus comprising: A cylindrical outer tube, with its upper end sealed and its lower end open; The inner tube, which is located inside the outer tube, is formed into a cylindrical shape with the upper end sealed and the lower end open, and can process the substrate inside. The manifold is formed in the shape of a cylinder and is located below the outer pipe and the inner pipe. It communicates with the internal space of the inner pipe and has an exhaust space that is isolated relative to the annular space between the inner pipe and the outer pipe. A processing gas nozzle supplies processing gas for processing the substrate into the inner tube; A purge gas nozzle supplies purge gas to the annular space; and A variable flow conductance section is provided in the partition wall between the annular space and the exhaust space, allowing gas to pass between the annular space and the exhaust space, and enabling the gas to pass through with variable flow conductance. The flow-guiding variable part has at least one threaded hole that passes through the partition wall and a screw that engages with the threaded hole.

2. The substrate processing apparatus as claimed in claim 1, wherein, A mounting component is provided at the lower end of the inner tube, which allows the inner tube to be inserted into the opening of the cylindrical manifold and can be detachably mounted on an annular inward flange formed on the inner circumference of the manifold.

3. The substrate processing apparatus as described in claim 1 or 2, wherein, have: A first pressure gauge for detecting the pressure in the internal space; and A second pressure gauge for detecting the pressure in the annular space.

4. The substrate processing apparatus as described in claim 1 or 2, wherein, The inner tube is formed of a material having a coefficient of linear expansion of less than ±8% relative to the coefficient of linear expansion of the deposits accumulated on the surface inside the inner tube when the substrate is processed by the processing gas.

5. The substrate processing apparatus as claimed in claim 4, wherein, The inner tube is formed of a material having a coefficient of linear expansion that is substantially equal to that of the accumulation.

6. The substrate processing apparatus as claimed in claim 4, wherein, The deposit is silicon, and the inner tube is a sintered body made primarily of silicon carbide.

7. The substrate processing apparatus as claimed in claim 2, wherein, The inward flange and the mounting component constitute the partition wall portion.

8. The substrate processing apparatus as claimed in claim 2, wherein, The flow guide variable portion has a threaded hole formed on one of the inward flange and the mounting member, and a through hole formed on the other of the inward flange and the mounting member opposite to the threaded hole.

9. The substrate processing apparatus as claimed in claim 1 or 2, wherein, The variable flow guide part has multiple threaded holes, and one or more screws are screwed into one of the multiple threaded holes.

10. The substrate processing apparatus as claimed in claim 1 or 2, wherein, The screw has a vent hole along its axis that allows gas to pass through.

11. The substrate processing apparatus as claimed in claim 9, wherein, One of the screws having a vent hole along the axis that allows gas to pass through, and the screw without the vent hole, is screwed into each of the plurality of threaded holes.

12. The substrate processing apparatus as claimed in claim 1, wherein, It also has a pressure controller that can control the pressure of the purge gas supplied to the purge gas nozzle in conjunction with the target pressure mode of the processing chamber, which is the internal space of the inner tube.

13. The substrate processing apparatus as claimed in claim 2, wherein, The mounting component has: An annular inner tube support member is provided between the inwardly facing flange and the lower end of the inner tube; An annular inner tube fitting ring is disposed on the opposite side of the inner tube support, separated from the flange of the inner tube; Multiple first fixing screws that connect the inner tube fitting ring and the inner tube support to each other; An annular sealing flange located on the opposite side of the inner tube support, separated from the inwardly facing flange; and The plurality of second fixing screws connecting the sealing flange and the inner tube support to each other The inner tube support has multiple protrusions that project radially outward at intervals along the circumferential direction on its outer periphery. The inward flange has multiple cuts that allow the plurality of protrusions to pass through.

14. The substrate processing apparatus as claimed in claim 2, wherein, The manifold includes: an upper flange located at one end of the cylindrical portion and connected to the outer tube via a first sealing material; a lower flange located at the other end of the cylindrical portion and connected to a housing supporting the outer tube via a second sealing material; and an inwardly facing flange located on the inner circumference of the cylindrical portion and supporting the inner tube. The flow guide variable part is provided on the inward flange or the mounting component.

15. The substrate processing apparatus as claimed in claim 1 or 2, wherein, The exhaust space of the manifold communicates directly with the internal space of the inner pipe without passing through the annular space. The manifold is provided with an exhaust port for discharging the gas inside the inner tube.

16. The substrate processing apparatus as claimed in claim 2, wherein, The substrate housed inside the inner tube is subjected to a process of depositing a film of 2 μm or more.

17. A substrate processing method using the substrate processing apparatus of claim 1, the substrate processing method comprising the following steps: In a substrate processing step, processing gas is supplied to the inner tube on which the substrate is disposed to process the substrate, and purge gas is supplied to the annular space. The processing gas supplied to the inner tube is discharged to the outside of the manifold through the exhaust space, and the purge gas in the annular space is discharged to the outside of the manifold through the variable flow section and the exhaust space; and In the exhaust process, after the substrate processing process is completed, purge gas is supplied from the processing gas nozzle to the internal space and from the purge gas nozzle to the annular space, so that the processing gas in the internal space is discharged to the outside of the manifold through the exhaust space.

18. A method for manufacturing a semiconductor device, using the substrate processing apparatus of claim 1, wherein the method for manufacturing the semiconductor device comprises the following steps: In a substrate processing step, processing gas is supplied to the inner tube on which the substrate is disposed to process the substrate, and purge gas is supplied to the annular space. The processing gas supplied to the inner tube is discharged to the outside of the manifold through the exhaust space, and the purge gas in the annular space is discharged to the outside of the manifold through the variable flow section and the exhaust space; and In the exhaust process, after the substrate processing process is completed, purge gas is supplied from the processing gas nozzle to the internal space and from the purge gas nozzle to the annular space, so that the processing gas in the internal space is discharged to the outside of the manifold through the exhaust space.

19. A recording medium having a program recorded thereon, the program using the substrate processing apparatus of claim 1 to cause a computer included in the substrate processing apparatus to perform steps of processing a substrate, the steps being performed by means of the following steps: In the substrate processing step, processing gas is supplied to the inner tube on which the substrate is disposed to process the substrate, and purge gas is supplied to the annular space. The processing gas supplied to the inner tube is discharged to the outside of the manifold through the exhaust space, and the purge gas in the annular space is discharged to the outside of the manifold through the variable flow section and the exhaust space; and In the exhaust step, after the substrate processing step is completed, purge gas is supplied from the processing gas nozzle to the internal space and from the purge gas nozzle to the annular space, so that the processing gas in the internal space is discharged to the outside of the manifold through the exhaust space.

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