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

Abstract

To provide a substrate processing apparatus, a substrate processing method, a semiconductor device manufacturing method, and a gas rectifier that can stably measure temperature.SOLUTION: A substrate processing apparatus includes: a port that is provided in a processing vessel formed by a reaction tube 7 and a manifold 11, which accommodates and heat-processes substrates (wafers), and provides an optical path penetrating the inside and outside of the processing vessel; an optical window that is attached to the port and transmits light while maintaining the port airtight; a purge gas supplier that is disposed inside the processing vessel, and supplies purge gas to the inner surface of the optical window; and a partition that guides the purge gas from the purge gas supplier to the optical window.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In semiconductor device manufacturing methods, a vertical substrate processing apparatus may be used to form an oxide film or a metal film on a substrate (hereinafter referred to as a wafer). When forming a predetermined film on the wafer, the processing chamber is heated to a predetermined temperature while a processing gas is supplied into the processing chamber. To maintain the predetermined temperature, the substrate processing apparatus is provided with a temperature sensor, such as a radiation thermometer, to detect the temperature inside the processing chamber.

[0003] When a radiation thermometer is used, the temperature inside the processing chamber is measured based on radiant light incident from inside the processing chamber through an optical window. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-222167 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when measuring temperature using a radiation thermometer, the optical window is exposed to the processing chamber, and therefore contamination from processing gases, particles, and the like may accumulate on the optical window, which may make it difficult to obtain highly reproducible temperature measurements.

[0006] The present disclosure provides a technique that enables stable temperature measurement. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, there is provided a technology including: a port provided in a processing vessel that accommodates a substrate therein for heat treatment and that provides an optical path penetrating the inside and outside of the processing vessel; an optical window attached to the port and that transmits light while maintaining the port airtight; a purge gas supplier disposed inside the processing vessel and that supplies a purge gas to an inner surface of the optical window; and a partition that guides the purge gas from the purge gas supplier to the optical window. [Effects of the Invention]

[0008] According to the present disclosure, stable temperature measurement is possible. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a vertical cross-sectional view illustrating an example of a processing furnace according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional plan view showing an upper surface portion of a manifold in a processing furnace according to an embodiment of the present disclosure. [Figure 3] FIG. 2 is an enlarged longitudinal cross-sectional view of a main portion showing a viewport and its vicinity according to an embodiment of the present disclosure. [Figure 4] FIG. 1 is a perspective view of an insulating ring stack according to an embodiment of the present disclosure. [Figure 5] FIG. 2A is a perspective view of the gas rectifier, and FIG. 2B is a bottom view of the gas rectifier. [Figure 6] 1 is a flowchart illustrating a substrate processing method according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, one embodiment of the present disclosure will be described mainly with reference to Figures 1 to 6. Note that the drawings used in the following description are all schematic, and the dimensional relationships, ratios, etc. of the elements shown in the drawings do not necessarily match those of reality. Furthermore, the dimensional relationships, ratios, etc. of the elements do not necessarily match between multiple drawings.

[0011] First, an embodiment according to the present disclosure will be described with reference to Fig. 1. Fig. 1 shows a vertical cross-sectional view of a processing furnace 2 in a substrate processing apparatus 1 according to this embodiment. Note that Figs. 2 to 5 are configured in the same manner as the substrate processing apparatus 1 shown in Fig. 1, and elements that are substantially the same as those described in Fig. 1 are assigned the same reference numerals, and descriptions thereof will be omitted.

[0012] The substrate processing apparatus 1 according to this embodiment is configured as an apparatus for performing an annealing process on a plurality of SiC (silicon carbide) substrates aligned in a vertical direction, that is, a batch-type vertical SiC annealing apparatus. By configuring it as a batch-type processing apparatus, it becomes possible to process a large number of substrates at once, thereby improving productivity.

[0013] The substrate processing apparatus 1 has a processing furnace 2, into which a boat 3 serving as a substrate holder can be inserted and removed. The boat 3 is made of a heat-resistant material such as carbon graphite or SiC. The boat 3 is configured to hold multiple wafers 4 serving as substrates, each made of SiC or the like, stacked vertically in a horizontal position with their centers aligned. A boat insulation part 5 made of a heat-resistant material such as graphite (carbon graphite), SiC, or quartz is disposed below the boat 3. The boat insulation part 5 supports the boat 3 from below and is configured to prevent heat from an induction target 6 (described later) from being transferred downward into the processing furnace 2. The boat 3 loaded with multiple wafers 4 is loaded into the processing furnace 2, where heat treatment is performed. When the boat 3 is loaded into the processing furnace 2, the boat insulation part 5 is positioned near the opening of the reaction tube 7.

[0014] Next, the configuration of the processing furnace 2 included in the substrate processing apparatus 1 will be described.

[0015] 1, the processing furnace 2 is made of a heat-resistant material such as quartz or SiC, and includes a cylindrical reaction tube 7 that is closed at the top and open at the bottom. A processing chamber 8 is formed in the hollow cylindrical portion of the reaction tube 7. The processing chamber 8 is configured to accommodate the boat 3 holding the wafers 4.

[0016] A manifold 11 is disposed below the reaction tube 7 and concentrically with the reaction tube 7. The manifold 11 is made of, for example, stainless steel, and is formed in a cylindrical shape that extends vertically. The manifold 11 is provided to support the reaction tube 7 from below. An O-ring 9 is provided as a sealing member between the manifold 11 and the reaction tube 7. The manifold 11 is supported by a holder (not shown), so that the reaction tube 7 is installed vertically. The reaction tube 7 and the manifold 11 form a processing vessel.

[0017] The process furnace 2 includes an induction target 6 as a heating element to be heated by induction heating, and an induction coil 12 as an induction heating unit, i.e., a magnetic field generator. The induction target 6 is cylindrically formed from a conductive heat-resistant material such as dense carbon and is disposed within the reaction tube 7, surrounding the boat 3, i.e., the wafer 4 storage area. The induction target 6 is cylindrically formed with a closed top end and an open bottom end, and when placed on the manifold 11, it exhibits a certain degree of airtightness and particle intrusion prevention capabilities. The induction coil 12 is supported by a coil support 12a made of an insulating heat-resistant material and is disposed so as to surround the outer periphery of the reaction tube 7. The induction coil 12 is configured to receive AC power of, for example, 10 to 450 kHz and 10 to 200 kW from an AC power source 13. An AC magnetic field generated by passing an AC current through the induction coil 12 generates an induced current, i.e., an eddy current, in the induction target 6, which generates heat due to Joule heat. When the induction target 6 generates heat, the wafers 4 held in the boat 3 are heated to a predetermined processing temperature, for example, 1500°C to 2000°C, by the radiant heat emitted from the induction target 6. In order to prevent thermal damage, it is preferable to maintain the temperature of components below the processing furnace 2, such as the manifold 11, at a temperature of, for example, 200°C or less.

[0018] A heat insulator 14 made of, for example, carbon felt having excellent heat resistance is provided between the reaction tube 7 and the induction target 6. The heat insulator 14 is formed in a cylindrical shape with a closed upper end and an open lower end. By providing the heat insulator 14, it is possible to suppress the transfer of heat from the induction target 6 to the reaction tube 7 or to the outside of the reaction tube 7.

[0019] Furthermore, at a predetermined height on the inner surface of the induction target 6, a substantially annular or cylindrical support part 20 is provided inside the reaction tube 7 along the inner peripheral surface of the induction target 6. The support part 20 is concentric with the induction target 6, and a temperature measurement chip 15 protruding toward the center of the processing chamber 8 is supported on the inner surface.

[0020] A viewport 16 made of, for example, a transparent quartz material is formed on the upper surface of the manifold 11 (the surface exposed inside the reaction tube 7, i.e., the inner surface) at a position facing the temperature measurement chip 15. Furthermore, in the space below the processing chamber 8, at a position facing the temperature measurement chip 15 across the viewport 16, a radiation light reflecting mirror 17 and a radiation thermometer 18 serving as temperature detection means are provided. The radiation thermometer 18 can measure the temperature of the temperature measurement chip 15 by receiving radiation light such as infrared light that is emitted from the temperature measurement chip 15 as a target and reflected by the radiation light reflecting mirror 17.

[0021] The temperature measurement chip 15 and the induction target 6 are made of the same material, and furthermore, the temperature measurement chip 15 is provided close to the induction target 6, so that the temperature measurement chip 15 is heated in the same way as the induction target 6, and the temperature of the temperature measurement chip 15 becomes equal to the temperature of the induction target 6. Therefore, by measuring the temperature of the temperature measurement chip 15, the temperature of the induction target 6 can be accurately measured.

[0022] The radiation thermometer 18 is electrically connected to a temperature control unit (not shown). The temperature control unit controls the processing temperature of the wafer 4 to a desired temperature by adjusting the amount of electricity supplied from the AC power supply 13 to the induction coil 12 based on temperature information detected by the radiation thermometer 18. The induction target 6, the induction coil 12, the AC power supply 13, the temperature measurement chip 15, the viewport 16, and the radiation thermometer 18 mainly constitute a heating unit according to this embodiment.

[0023] 1 shows one each of the temperature measurement chip 15, viewport 16, radiation thermometer 18, and support part 20, but a plurality of viewports 16, for example, four viewports 16, are arranged along an imaginary circle concentric with the axis of the reaction tube 7. The temperature measurement chips 15, radiation thermometers 18, and support parts 20 are also arranged corresponding to the respective viewports 16, and furthermore, the temperature measurement chips 15 and support parts 20 are arranged at different heights.

[0024] An outer heat insulating wall 19, for example, of a water-cooled structure, which suppresses heat transfer from inside the processing chamber 8 to the outside, is provided outside the induction coil 12 so as to surround the processing chamber 8. Furthermore, a magnetic shield 21 is provided outside the outer heat insulating wall 19 to prevent the magnetic field generated by the induction coil 12 from leaking to the outside. The outer heat insulating wall 19 and the magnetic shield 21 may be integrally formed.

[0025] The process furnace 2 is provided with a first gas nozzle 22 having a first gas supply port 22a. The first gas nozzle 22 is disposed inside the induction target 6, vertically disposed between the wafer 4 accommodation area and the induction target 6. The first gas nozzle 22 is made of a heat-resistant material such as carbon graphite. The first gas supply port 22a may be provided at the upper end (tip) or side of the first gas nozzle 22. The downstream end of a first gas supply pipe 23 is connected to the upstream side of the first gas nozzle 22. The first gas supply pipe 23 is disposed so as to penetrate the manifold 11. A gas supply unit 24 is connected to the upstream end of the first gas supply pipe 23. Although only one first gas nozzle 22 is shown in FIG. 1, two gas nozzles are disposed between the wafer 4 accommodation area and the induction target 6.

[0026] A second gas supply pipe 25 is disposed in the vertical direction outside the induction target 6, between the heat insulator 14 and the reaction tube 7. A second gas supply port 26 is provided at the downstream end of the second gas supply pipe 25. The second gas supply pipe 25 is disposed so as to penetrate the manifold 11. A gas supply unit 24 is connected to the upstream end of the second gas supply pipe 25.

[0027] A first exhaust port 27 is provided in the side wall of the manifold 11 facing the first gas supply port 22a, below the boat insulation section 5, i.e., the wafer 4 accommodation area. A second exhaust port 28 is provided in the wall of the manifold 11 between the insulation body 14 and the reaction tube 7, on which the reaction tube 7 is mounted. The first exhaust port 27 and the second exhaust port 28 are connected to the upstream end of a branched exhaust pipe 29. The exhaust pipe 29 is provided with, in order from the upstream side, a pressure sensor 31 as a pressure detector, an APC (Auto Pressure Controller) valve 32 as a pressure regulator, and a vacuum pump 33 as a vacuum exhaust device. The pressure sensor 31, the APC valve 32, and the vacuum pump 33 are electrically connected to a pressure control unit (not shown). The pressure control unit controls the opening of the APC valve 32 based on pressure information measured by the pressure sensor 31, thereby controlling the pressure in the process chamber 8 to a predetermined pressure at a predetermined timing.

[0028] By providing the first exhaust port 27 as described above, the gas supplied from the first gas supply port 22a into the processing chamber 8, i.e., the processing gas, flows downward within the processing chamber 8, i.e., inside the induction target 6, through the region where the boat insulation part 5 is provided, and is exhausted from the first exhaust port 27. At this time, the entire wafer 4 is efficiently and uniformly exposed to the gas.

[0029] Furthermore, by providing the second exhaust port 28 as described above, the inert gas such as nitrogen supplied into the processing chamber 8 from the second gas supply port 26 acts as a purge gas, flows between the reaction tube 7 and the insulator 14, and is exhausted from the second exhaust port 28. This makes it possible to quickly exhaust contaminants and the like evaporated from the induction target 6 and the insulator 14 before they diffuse into the induction target 6, and also makes it possible to prevent the processing gas from penetrating between the induction target 6 and the reaction tube 7.

[0030] Furthermore, the boat 3 can be carried into the processing chamber 8 (i.e., boat loading) and carried out (i.e., boat unloading) by an elevator mechanism (not shown). When the boat 3 is carried into the processing chamber 8, the opening of the processing furnace 2 (i.e., the furnace port) is airtightly closed by a seal cap 34 via a sealing member such as an O-ring. A boat rotation mechanism 35 that supports the boat insulation part 5 penetrates the center of the seal cap 34, and the boat 3 can be rotated by the boat rotation mechanism 35.

[0031] The controller 36 controls each part of the substrate processing apparatus 1 and includes a central processing unit (CPU) 37, a main memory device 38, and an auxiliary memory device 39. The auxiliary memory device 39 stores recipe information including a series of operations for causing the substrate processing apparatus 1 to perform an annealing process and the like, and a program executed by the CPU 37 to actually control the substrate processing apparatus 1 based on the recipe information. The auxiliary memory device 39 may include a recording medium such as an optical disk. Note that a gas rectifier 42 and a heat insulating ring stack 43, which will be described later, are not shown in FIG. 1.

[0032] Next, the opening of the reaction tube 7 and the surrounding structure will be described with reference to Figures 2 and 3. Figure 2 is a cross-sectional view of the processing furnace 2 in the vicinity of and above the upper surface of the manifold 11.

[0033] On the upper surface of the manifold 11, there are provided four viewports 16 (16a, 16b, 16c, 16d) arranged in sequence along an imaginary circle concentric with the axis of the reaction tube 7, inside the induction target 6, i.e., inside the reaction tube 7; a purge gas supplier 41 arranged to supply an inert gas as a purge gas (e.g., argon (Ar) or nitrogen (N2)) toward the viewports 16a to 16d; and a partially open, annular gas rectifier 42 arranged above the upper surface of the manifold 11.

[0034] The purge gas supplier 41 is disposed on the upper surface of the manifold 11 adjacent to the viewport 16a, and is fluidly connected to the gas supply unit 24, and ejects the purge gas supplied from the gas supply unit 24 in the circumferential direction of the imaginary circle. The purge gas supplier 41 may be connected to the second gas supply pipe 25, and may extract and eject a portion of the purge gas supplied to the second gas supply pipe 25.

[0035] The viewports 16a to 16d and the purge gas supplier 41 are respectively arranged along the circular opening of the reaction tube 7 and along the inner circumference of the induction target 6, on the inner circumferential side of the reaction tube 7. The gas rectifier 42 has a plate portion 42a arranged parallel to the upper surface of the manifold 11 so as to partially cover the upper parts of the viewports 16a to 16d, and a partition 42b serving as a guide extending upward parallel to the axis of the reaction tube 7 on the inner circumferential side above the viewports 16a to 16d. The partition 42b is made of a highly heat-resistant material, such as graphite, and is formed as an arc-shaped plate on the inner circumferential side of the viewports 16a to 16d and the purge gas supplier 41, and along the arrangement of the viewports 16a to 16d. Furthermore, one end of partition 42b, i.e., the end on the purge gas supplier 41 side, is formed with bent portion 42c that is bent radially outward at a right angle or approximately a right angle, and the other end of partition 42b, i.e., the end on the viewport 16d side, extends further toward the other end side than viewport 16d. Bent portion 42c prevents the purge gas injected from purge gas supplier 41 from drawing in surrounding unclean gas and flowing together with it into viewports 16a to 16d.

[0036] Plate portion 42a is configured by, for example, forming a flat graphite plate into a ring shape with a portion open, and two first gas nozzles 22 are arranged in open ring portion 55a, which is the open portion of plate portion 42a. That is, open ring portion 55a is configured to prevent contact between plate portion 42a and the bases of first gas nozzles 22, 22 disposed in the vertical direction. Plate portion 42a also has notches 53a-53d directly above viewports 16a-16d.

[0037] The upper end of the bent portion 42c is connected to the end of the plate portion 42a at approximately a right angle. The upper end of the partition 42b is connected to the inner peripheral end of the plate portion 42a at approximately a right angle. The partition 42b, the bent portion 42c, and the plate portion 42a are not necessarily connected by integral formation. They may be formed separately and positioned so that the upper ends of the partition 42b and the bent portion 42c contact or are close to the end of the plate portion 42a. The gas rectifier 42 blocks radiation from the induction target 6, which has reached a high temperature. This prevents the upper surface 11a of the manifold 11 from being heated by radiation, and also prevents unwanted light from entering the viewport 16.

[0038] As described above, the space around the purge gas supplier 41 and the viewports 16a to 16d is blocked radially by the partition 42b of the gas rectifier 42 and the induction target 6, blocked on one side in the circumferential direction by the bent portion 42c, and blocked upward by the plate portion 42a except for the notches 53a to 53d. Without the gas rectifier 42, the purge gas from the purge gas supplier 41 would easily flow down into the annular space between the boat insulation portion 5 and the manifold 11 before reaching the viewport 16d and be discharged from the first exhaust port 27. By providing the gas rectifier 42, a flow path is formed in which the purge gas from the purge gas supplier 41 passes above the viewports 16a to 16d before being discharged.

[0039] 3, the viewport 16 is composed of a port 47 formed to extend in the longitudinal direction (tube axis direction) of the reaction tube 7 (processing vessel), a cylindrical portion 48 inserted into the port 47, a sealing member 49 that airtightly seals the gap between the port 47 and the cylindrical portion 48, and an optical window 51 held by the cylindrical portion 48. Note that although only one viewport 16 and its components are shown in FIG. 3, a plurality of viewports 16 and their components, for example, four viewports 16 and their components, may be provided.

[0040] The port 47 is a cylindrical member provided so that its upper end opens upward on the upper surface 11a of the manifold 11 (i.e., the inner surface 11a exposed inside the reaction tube 7), i.e., on a plane perpendicular to the tube axis at the opening side of the reaction tube 7, and the inside and outside of the reaction tube 7 are communicated with each other via the port 47.

[0041] The cylindrical portion 48 is a cylindrical member made of, for example, SUS, and is attached to the inside of the port 47. A seal member 49, made of, for example, a heat-resistant adhesive or heat-resistant resin, is provided between the outer surface of the lower end of the cylindrical portion 48 and the inner surface of the port 47, and the seal member 49 provides an airtight seal between the inner periphery of the port 47 and the outer periphery of the cylindrical portion 48. A disk-shaped optical window 51, made of, for example, transparent sapphire, is airtightly brazed and fixed to the inner surface of the upper end of the cylindrical portion 48. Therefore, the optical window 51 and the seal member 49 isolate the atmosphere inside and outside the viewport 16. The upper surface of the optical window 51 is substantially flush with the inner surface 11a of the manifold 11 or is slightly lower than the inner surface 11a.

[0042] A lens barrel 18a having a radiation reflection mirror 17 is provided at the lower end of the port 47, and a radiation thermometer 18 is provided on the reflected optical axis of the radiation reflection mirror 17. That is, the port 47 provides an optical path parallel to the tube axis for guiding the radiation to the radiation thermometer 18. Therefore, the optical path of the radiation penetrates the inside and outside of the processing chamber 8 and extends in the longitudinal direction of the reaction tube 7 inside the induction target 6, so that the radiation thermometer 18 can measure the temperature of the temperature measurement chip 15. The optical path of the radiation passes through the notches 53a to 53d of the gas rectifier 42 to reach the temperature measurement chip 15.

[0043] When purge gas is ejected from the purge gas supplier 41, the purge gas is supplied toward the upper surface (the surface exposed inside the reaction tube 7, i.e., the inner surface) of the viewport 16 (viewport 16a). The partition 42b and the induction target 6 block the radial direction (horizontal direction), the bent portion 42c blocks one side in the circumferential direction (rear), and the plate portion 42a blocks the upper side. Therefore, the purge gas is guided by the partition 42b and the induction target 6 and flows from the viewport 16a toward the viewport 16d. The purge gas that has passed through the viewport 16d continues to flow circumferentially along the induction target 6 and gradually flows down into the manifold 11.

[0044] Supplying purge gas forms a diffusion barrier for the process gas and blows away particles, thereby suppressing contamination of the viewport 16. Furthermore, because the purge gas flows over the top surface of the viewport 16, it is possible to suppress a temperature rise in the viewport 16 and prevent the viewport 16 from being destroyed by heat. Furthermore, because the optical window 51 is mounted so that it is substantially flush with the top surface 11a (inner surface 11a) of the manifold 11, the purge gas can be sprayed efficiently. Furthermore, because a flow path is formed that is surrounded above, below, left, and right by the gas rectifier 42 having the partition 42b extending substantially parallel to the optical path, the induction target 6, and the manifold 11, the purge gas is supplied to the viewport 16d without being dispersed, thereby further improving the effects of suppressing contamination and temperature rise in the viewport 16.

[0045] Next, the details of the insulating ring stack 43 will be described with reference to Figures 4, 5(A), and 5(B). The insulating ring stack 43 is configured as an insulating assembly in which insulating rings 44 are stacked in multiple layers and is placed between the boat insulation section 5 and the induction target 6. In this example, the insulating ring stack 43 uses a gas rectifier 42 for the lowest insulating ring. The insulating ring stack 43 is positioned and integrated with fasteners 46, such as bolts, through holes 45 formed at predetermined angular intervals. In addition, the stacked insulating rings 44 are placed near the opening of the reaction tube 7 to improve insulation between the inside and outside of the process chamber 8 and suppress temperature increases in the manifold 11. The insulating ring stack 43 is made of a heat-resistant material, such as graphite, SiC, or quartz.

[0046] The multiple insulation rings 44 basically have the same shape and are annular plates with an opening in the center for inserting the boat insulation part 5. The insulation ring 44 has four holes 45 formed at predetermined angular intervals, notches 53a to 53d formed on the outer periphery, a notch 54 formed on the outer periphery spaced apart from the notches 53a to 53d, and a rectangular notch 55 formed on the inner periphery.

[0047] Four fasteners 46, such as a set of bolts and nuts, are inserted into the holes 45 to secure the insulating rings 44. Regular spacers may be inserted along with the insulating rings 44 to maintain a constant distance between adjacent insulating rings 44. Fasteners 46 protrude from the upper and lower ends of the insulating ring stack 43. When the insulating ring stack 43 is placed on the upper surface 11a of the manifold 11, the fasteners 46 function as feet. It is desirable that the center and orientation of the insulating ring stack 43 be accurately positioned so that the notches 53a to 53d are positioned directly above the viewports 16a to 16d. If recesses that fit with the fasteners 46 are provided on the upper surface 11a, the fasteners 46 function as positioning means.

[0048] Notch 54 is a notch for placing a profile thermocouple during temperature calibration. Notch 55 is for preventing contact between heat insulating ring 44 and first gas nozzles 22, 22, and is arranged in the same direction as open ring portion 55a. Notches 53a to 53d ensure that the optical path of light thermally radiated from each temperature measurement chip 15 is not blocked by heat insulating ring 44.

[0049] Among the insulating rings constituting the insulating ring stack 43, the second insulating ring 44a from the bottom has an open ring portion 55a similar to that of the gas rectifier 42, unlike the other insulating rings 44. The open ring portion 55a is located opposite the notch 55, and the bases of the first gas nozzles 22 are disposed in the open ring portion 55a. In this embodiment, of the insulating rings 44 stacked, the insulating ring 44 at the height where the bases of the first gas nozzles 22 are located is the insulating ring 44a with the open ring portion 55a, thereby preventing contact between the insulating ring 44 and the first gas nozzles 22. Alternatively, the first insulating ring from the bottom of the insulating ring stack 43 and the second insulating ring from the bottom may be identical to the insulating ring 44a, and only the partition 42b of the gas rectifier 42 may be disposed between the manifold 11 and the lowest insulating ring.

[0050] Next, substrate processing using the above-described substrate processing apparatus 1 will be described with reference to the flowchart in Fig. 6. Here, an example will be described in which argon (Ar) gas is supplied as a processing gas into the processing chamber 8 and an annealing process is performed to remove oxygen from the wafer 4. In this specification, the processing temperature refers to the temperature of the wafer 4 or the temperature of the processing chamber 8, and the processing pressure refers to the pressure inside the processing chamber 8. In the following description, the operation of each component of the substrate processing apparatus 1 is controlled by a controller 36.

[0051] The explanation will be given from the state where the seal cap 34 is lowered by a lifting mechanism (not shown), the boat 3 is carried out from the reaction tube 7, that is, the boat is unloaded, and there are no wafers 4 in the boat 3. (Wafer charge and boat load) When a FOUP containing wafers 4 is loaded into the substrate processing apparatus 1, a transfer machine (not shown) transfers the wafers 4 to the boat 3 (STEP: 01). When multiple wafers 4 are loaded into the boat 3, i.e., wafer charging, the seal cap 34 is raised by a lifting mechanism (not shown), and the boat 3 is carried inside the induction target 6 in the processing chamber 8, i.e., boat loading, and the lower opening of the reaction tube 7 is airtightly closed (sealed) by the seal cap 34 (STEP: 02).

[0052] (Pressure and temperature adjustment) The processing chamber 8 is evacuated, i.e., decompressed, by the vacuum pump 33. The atmosphere in the processing chamber 8 flows linearly or approximately linearly through the exhaust pipe 29 and is exhausted through the vacuum pump 33. Once the pressure in the processing chamber 8 is evacuated, Ar gas is supplied into the processing chamber 8. The Ar gas is controlled to a predetermined flow rate by the gas supply unit 24 and supplied into the processing chamber 8 from the tip of the first gas nozzle 22 via the first gas supply pipe 23 and the first gas nozzle 22. Simultaneously with the supply of Ar gas, i.e., with the seal cap 34 closing the opening of the manifold 11, the gas supply unit 24 supplies purge gas, controlled to a desired flow rate, from the second gas supply port 26 through the second gas supply pipe 25 to between the reaction tube 7 and the heat insulator 14. The purge gas is ejected upward, diffuses circumferentially along the ceiling, descends along the circumferential surface, and is exhausted to the outside of the processing chamber 8 via the second exhaust port 28 and the exhaust pipe 29. The pressure inside the processing chamber 8 is measured by a pressure sensor 31, and based on this measured pressure information, the APC valve 32 is feedback-controlled to adjust the pressure to a predetermined pressure (degree of vacuum).

[0053] In parallel with the supply of purge gas from second gas supply port 26, purge gas is supplied from purge gas supply device 41. The purge gas is sprayed sequentially along the flow path formed by gas rectifier 42 onto the upper surfaces (inner surfaces of processing chamber 8) of viewports 16a to 16d (i.e., each optical window 51 of each viewport 16), and then exhausted to the outside of processing chamber 8 via second exhaust port 28 and exhaust pipe 29. Supply of purge gas from purge gas supply device 41 suppresses contamination and temperature rise of each optical window 51 of viewports 16a to 16d.

[0054] To bring the wafers 4 in the processing chamber 8 to a predetermined temperature, a predetermined AC power is supplied from the AC power supply 13 to the induction coil 12, an induced current is passed through the induction target 6 to raise the temperature of the induction target 6, and the induction target 6 heats the wafers 4 from the surroundings. By heating by induction heating, the wafers 4 can be heated efficiently. At this time, the state of current flowing to the induction coil 12 is feedback-controlled based on temperature information detected by the radiation thermometer 18 so that the entire wafers 4 loaded in the boat 3 have a predetermined temperature distribution. Also, the boat rotation mechanism 35 starts rotating the boat 3 and the wafers 4.

[0055] (Substrate processing) The wafer 4 is heated in an Ar atmosphere at a predetermined temperature for a predetermined time, thereby activating the ion-implanted impurities and removing oxygen from the surface, thereby producing an annealed wafer (STEP: 03).

[0056] (Boat unloading and wafer discharging) After the annealed wafers are produced, the induction coil 12 is de-energized, and the wafers 4 are cooled until their temperature drops to a predetermined temperature. After the wafers 4 have cooled, the APC valve 32 is closed, and the pressure inside the processing chamber 8 is returned to atmospheric pressure. Thereafter, the seal cap 34 is lowered by a lifting mechanism (not shown), and the boat 3 is removed from the reaction tube 7, i.e., the boat is unloaded (STEP: 04).

[0057] After the boat 3 is removed, that is, while the seal cap 34 is not closing the opening of the processing chamber 8, a cooling process is performed on the wafers 4 and the boat insulation part 5 (STEP: 05).

[0058] When the wafers 4 and the boat insulation section 5 have cooled to a predetermined temperature, the processed wafers 4 loaded into the boat 3 are stored in the FOUP by a transfer machine (not shown), and the FOUP is transported out of the substrate processing apparatus 1 (STEP: 06), completing the substrate processing.

[0059] The processing conditions for Ar annealing the wafer 4 are, for example, as follows. Processing temperature (wafer temperature): 1500℃~1900℃ Processing pressure (pressure inside the processing chamber): 1 Pa to atmospheric pressure Ar gas: 1sccm to 5SLM, N2 gas: 1sccm to 5SLM, By setting each processing condition to a value within the respective range, the film formation process can be carried out appropriately. Note that the expression of a numerical range such as "1500°C to 1900°C" above means that the lower limit and upper limit are included in the range. For example, "1500°C to 1900°C" means "1500°C or higher and 1900°C or lower." The same applies to other numerical ranges.

[0060] According to this aspect, one or more of the following effects can be obtained.

[0061] In this embodiment, an arc-shaped partition 42b is provided along the row of viewports 16a to 16d (optical windows 51), and the purge gas ejected from the purge gas supply device 41 is guided to the gas rectifier 42 and sprayed sequentially onto the viewports 16a to 16d. In addition, the partition 42b extends from the rear of the purge gas supply device 41 beyond the viewport 16 that is farthest from the purge gas supply device 41, so that the purge gas can be delivered to the viewport 16 that is farthest from the purge gas supply device 41 without dissipating.

[0062] Therefore, the flow rate of the purge gas can be reduced, foreign matters such as particles deposited or about to deposit on the view port 16 can be blown away to suppress contamination, and the view port 16 can be cooled to suppress a temperature rise, which enables stable temperature measurement with high reproducibility by the radiation thermometer 18 and reduces the frequency of in-furnace maintenance of the reaction tube 7.

[0063] Furthermore, by supplying purge gas, a region with a high purge gas concentration, i.e., a low concentration of deposition gas, can be formed around the viewport 16, thereby forming and maintaining a concentration gradient that prevents deposition gas from reaching the viewport 16.

[0064] In this embodiment, the optical window 51 of the viewport 16 is provided in the reaction tube 7 so as to be exposed above the upper surface of the manifold 11. That is, the viewport 16 is arranged so that the optical window 51 faces upward, but the divider 42b of this embodiment can be applied even if the viewport 16 is arranged so that the optical window 51 faces sideways, for example. Furthermore, in this embodiment, the notch 53 is formed on the edge on the outer periphery of the heat insulating ring 44, but it may also be formed on the inner periphery. The position where the notch 53 is formed is selected appropriately depending on the position where the viewport 16 is provided.

[0065] 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, for example, to a case where a film is formed using a single-wafer-type substrate processing apparatus that processes one or several substrates at a time. Furthermore, in the above-described embodiment, an example of forming a film using a substrate processing apparatus having a hot-wall processing furnace has been described. 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 processing furnace. [Explanation of symbols]

[0066] 1. Substrate processing equipment 4 wafers 7 Reaction tube 16 viewports 41 Purge gas supply 42 Gas rectifier 47 ports 51 Optical window

Claims

1. a port provided in a processing vessel for accommodating a substrate therein and performing a heat treatment thereon, the port providing an optical path penetrating the inside and outside of the processing vessel; an optical window attached to the port and allowing light to pass through while maintaining the port airtight; a purge gas supplier disposed inside the processing vessel and supplying a purge gas to an inner surface of the optical window; and a partition for directing the purge gas from the purge gas supplier to the optical window.

2. The substrate processing apparatus according to claim 1 , wherein the partition is provided substantially parallel to the optical path.

3. 2. The substrate processing apparatus according to claim 1, wherein the port and the purge gas supplier are arranged along an inner periphery of a circular opening of the processing vessel, and the partition is formed in an arc shape on the inner periphery of the port and the purge gas supplier.

4. The substrate processing apparatus according to claim 1 , wherein the ports are arranged along an imaginary circle that is concentric with the axis of the processing vessel, and the partition extends along the arrangement of the ports.

5. 2. The substrate processing apparatus of claim 1, further comprising a cylindrical heating element disposed inside the processing vessel and heated by induction, wherein the port is provided along an inner periphery of the heating element so that the optical path extends in the longitudinal direction of the processing vessel inside the heating element.

6. 2. The substrate processing apparatus according to claim 1, wherein the port is provided in a cylindrical manifold having a surface perpendicular to a tube axis of the processing vessel on the opening side of the processing vessel, the port facing upward.

7. 2. The substrate processing apparatus according to claim 1, further comprising a cylindrical portion formed in a cylindrical shape and attached to the inside of the port, the cylindrical portion airtightly fixing and holding the optical window therein, the port having a sealing member that airtightly seals the outer periphery of the cylindrical portion.

8. 2. The substrate processing apparatus according to claim 1, further comprising: a gas rectifying device including the partition and a plate portion disposed in the processing vessel so as to partially cover an upper portion of the port, the plate portion and the partition being connected at approximately a right angle.

9. The substrate processing apparatus according to claim 8 , wherein the plate portion is formed in an open ring shape, and the partition is connected to an edge of the inner periphery or the outer periphery of the plate portion.

10. 10. The substrate processing apparatus according to claim 9, further comprising: a heat insulating assembly having a plurality of heat insulating rings held in multiple stages and the gas rectifier, the heat insulating assembly being installed near an opening of the processing vessel.

11. 6. The substrate processing apparatus of claim 5, further comprising an insulating ring disposed near an opening of the processing vessel, the insulating ring covering an area surrounded by the partition and the heating element and directing purge gas from the purge gas supplier to the optical window.

12. The substrate processing apparatus of claim 6 , wherein the optical window is disposed within the port so as to be substantially flush with an inner surface of the manifold.

13. 2. The substrate processing apparatus according to claim 1, further comprising a substantially cylindrical support member attached to the port from the inside of the processing vessel, the support member supporting a target of a radiation thermometer.

14. The substrate processing apparatus according to claim 11 , wherein the heat insulating ring has a notch on an inner or outer circumferential edge thereof for ensuring the optical path.

15. The substrate processing apparatus according to claim 1 , wherein the partition is made of graphite.

16. a processing vessel for accommodating a substrate therein for heat treatment, the processing vessel having a port for providing an optical path penetrating the inside and outside of the processing vessel; an optical window attached to the port for transmitting light while maintaining the port's airtightness; a process for introducing purge gas from a purge gas supplier disposed inside the processing vessel to the optical window; and a process for introducing purge gas from the purge gas supplier to the optical window by a partition.

17. A method for manufacturing a semiconductor device, comprising: a process vessel for accommodating a substrate therein and performing a heat treatment thereon, the process vessel having a port that provides an optical path penetrating the inside and outside of the process vessel; an optical window attached to the port that transmits light while maintaining the port's airtightness; a process of guiding purge gas from a purge gas supplier disposed inside the process vessel to the optical window; and a partition that guides the purge gas from the purge gas supplier to the optical window.

18. A gas rectifying device comprising: a plate portion arranged in a processing vessel for accommodating substrates therein and performing heat treatment, facing a port that provides an optical path penetrating the inside and outside of the processing vessel and partially covering the port; and a partition arranged approximately parallel to the optical path, wherein the plate portion and the partition are arranged between a purge gas supplier arranged adjacent to the port in the processing vessel and an optical window attached to the port.

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