Thermal insulation structure, substrate processing device, semiconductor device manufacturing method, substrate processing method, and storage medium

Abstract

The present invention provides a technology for improving the thermal insulation performance of the lower portion of a processing chamber and shortening the temperature stabilization time within the processing chamber. The thermal insulation structure, located near the furnace opening of a heat treatment furnace with a temperature gradient, comprises multiple thermal insulation panels. These panels comprise a metal insulation material and a quartz or ceramic sealing member covering the front and back surfaces of the insulation material. The insulation material is disposed within a vacuum cavity formed within the sealing member, and the multiple thermal insulation panels are spaced apart from each other.

Description

Technical Field

[0001] The present invention relates to a heat insulation structure, a substrate processing device, a method for manufacturing a semiconductor device, a substrate processing method, and a storage medium. Background Art

[0002] For thermal processing of substrates (wafers) in the manufacturing process of semiconductor devices (equipment), a vertical substrate processing apparatus is used, for example. In a vertical substrate processing apparatus, multiple substrates are arranged vertically and held by a substrate holder, which is then moved into a processing chamber. Then, while the substrates are heated by a heater located outside the processing chamber, a processing gas is introduced into the processing chamber to perform thin film formation, for example, on the substrates.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-49853

[0006] Patent Document 2: International Publication No. 2016 / 135876 Pamphlet

[0007] Patent Document 3: International Publication No. 2019 / 053807 Pamphlet Summary of the Invention

[0008] Problems to be solved by the invention

[0009] In the vertical substrate processing apparatus described above, a sub-heater is sometimes provided in the lower portion of the processing chamber where a large amount of heat is dissipated outside the furnace, and the substrate is heated by both the main heater and the sub-heater provided outside the processing chamber.

[0010] However, if the sub-heater is set up in this way, if the temperature rise of the sub-heater cannot track the main heater, it will take time to stabilize the temperature of the processing chamber. In addition, since the sub-heater heats the center of the substrate, the temperature distribution within the substrate surface may become uneven.

[0011] The object of the present invention is to provide a technology that improves the thermal insulation performance of the lower part of the processing chamber and shortens the temperature stabilization time in the processing chamber.

[0012] Solutions to Problems

[0013] According to one embodiment of the present invention, a technology is provided having an insulating structure, which is arranged near a furnace mouth having a temperature gradient of a heat treatment furnace, wherein the insulating structure is provided with a plurality of insulating plates, each of which has a metal insulating material and a sealing component made of quartz or ceramic covering the front and back surfaces of the insulating material, and the insulating material is arranged in a vacuum cavity formed inside the sealing component, and the plurality of insulating plates are arranged at intervals from each other.

[0014] Effects of the Invention

[0015] According to the present invention, a technology can be provided that can improve the thermal insulation performance of the lower portion of a processing chamber and shorten the temperature stabilization time in the processing chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of a vertical furnace of a substrate processing apparatus suitable for use in an embodiment of the present invention, and is a diagram showing the interior of the furnace in a longitudinal cross-sectional view.

[0017] Figure 2 1 is a longitudinal sectional view showing a cover heater and its surroundings of a substrate processing apparatus preferably used in an embodiment of the present invention.

[0018] Figure 3 It is a perspective view showing a cover heater of a substrate processing apparatus suitable for use in the embodiment of the present invention.

[0019] Figure 4 (A) and (B) are perspective views for explaining a heat insulating structure of a substrate processing apparatus preferably used in the embodiment of the present invention.

[0020] Figure 5 (A) is a plan view showing a heat insulating plate constituting a heat insulating structure suitable for use in an embodiment of the present invention, and (B) is a longitudinal sectional view showing a heat insulating plate of a substrate processing apparatus suitable for use in an embodiment of the present invention.

[0021] Figure 6 (A) and (B) are longitudinal cross-sectional views for explaining the structure of a heat shielding board preferably used in the embodiment of the present invention.

[0022] Figure 7 1 is a schematic block diagram of a controller of a substrate processing apparatus suitable for use in an embodiment of the present invention, and is a diagram showing a control system of the controller in a block diagram. DETAILED DESCRIPTION

[0023] Below, use Figure 1 An embodiment of the present invention will be described.

[0024] like Figure 1As shown, in this embodiment, the substrate processing apparatus 1 is configured as a vertical heat treatment apparatus for performing a heat treatment process in the manufacture of semiconductor integrated circuits, and is equipped with a furnace 2. The furnace 2 is a cylindrical electric furnace and is supported by a heater base 2A serving as a retaining plate and is installed vertically relative to the installation floor of the substrate processing apparatus 1. In order to uniformly heat the interior of the furnace, a heater 3 serving as a first heater is provided on the inner surface side of the furnace 2. As described later, the heater 3 also functions as an activation mechanism (excitation unit) that activates (excites) the gas by heat.

[0025] A reaction tube 4, which serves as a reaction vessel (processing vessel), is located inside the furnace 2. The reaction tube 4 is made of a heat-resistant material, such as infrared-transmissive quartz (SiO2) or silicon carbide (SiC), which is close to a black body. It is cylindrical, with a closed upper end and an open lower end. A gas supply space (supply duct) 4A and a gas exhaust space (exhaust duct) 4B are formed on the outside of the reaction tube 4, facing each other and projecting outward. Furthermore, a flange 4C is formed at the lower end of the reaction tube 4, projecting outward. The flange 4C is connected to the manifold 5, the counterpart component on the cover 19 side, via an O-ring 5A, which serves as a sealing member.

[0026] A processing chamber 6 is formed in the hollow portion of the reaction tube 4. The processing chamber 6 is configured to accommodate wafers 7 via a wafer boat 21 described later. The processing chamber 6 and the gas supply space 4A and the gas exhaust space 4B are separated by the reaction tube 4 (inner wall).

[0027] The manifold 5 is cylindrical and made of metal, and is provided to support the lower end of the reaction tube 4. The inner diameter of the manifold 5 is formed to be larger than the inner diameter of the reaction tube 4 (the inner diameter of the flange portion 4C). This allows an annular space, described below, to be formed between the lower end of the reaction tube 4 (the flange portion 4C) and the cap 19 provided at the lower end (one end) of the reaction tube 4.

[0028] One or more nozzles 8 are provided in the gas supply space 4A. Gas supply pipes 9 for supplying processing gas (raw gas) pass through the manifold 5 and are respectively connected to the nozzles 8. On the flow path of each gas supply pipe 9, a mass flow controller (MFC) 10 as a flow controller and a valve 11 as an opening and closing valve are provided in sequence from the upstream direction. On the downstream side of the valve 11, a gas supply pipe 12 for supplying inert gas is connected to the gas supply pipe 9. On the gas supply pipe 12, an MFC 13 and a valve 14 are provided in sequence from the upstream direction. The processing gas supply system, i.e., the processing gas supply part, is mainly composed of the gas supply pipe 9, the MFC 10, and the valve 11. In addition, the inert gas supply system, i.e., the inert gas supply part, is composed of the gas supply pipe 12, the MFC 13, and the valve 14. In addition, it is also conceivable to include the gas supply pipe 12, the MFC 13, and the valve 14 in the processing gas supply part (processing gas supply system).

[0029] Nozzle 8 is installed in gas supply space 4A, rising from the bottom of reaction tube 4. One or more gas supply holes 8A are provided on the side or top of nozzle 8 for supplying gas. Gas supply holes 8A, opening toward the center of reaction tube 4, can spray gas toward wafer 7. A plurality of laterally elongated supply slits 4E are vertically arranged on the inner wall between gas supply space 4A and processing chamber 6 at intervals corresponding to wafer 7.

[0030] On the inner wall between the gas exhaust space 4B and the processing chamber 6, a plurality of laterally long exhaust slits 4F serving as the first exhaust portion (first exhaust port) are vertically arranged in a manner corresponding to the supply slits 4E. An exhaust port 4D connected to the gas exhaust space 4B is formed near the lower end of the reaction tube 4. An exhaust pipe 15 for discharging the ambient gas in the processing chamber 6 is connected to the exhaust port 4D. An exhaust port 4G is formed on the inner wall below the gas exhaust space 4B (the wall between the gas exhaust space 4B and the processing chamber 6). In addition, an exhaust port 4H is formed on the flange portion 4C to connect the processing chamber 6 and the lower end of the gas exhaust space 4B. The exhaust ports 4G and 4H mainly function to discharge the purge gas described later.

[0031] A vacuum pump 18 serving as a vacuum exhaust device is connected to the exhaust pipe 15 via a pressure sensor 16 serving as a pressure detector (pressure gauge) for detecting the pressure in the processing chamber 6 and an APC (Auto Pressure Controller) valve 17 serving as a pressure regulator (pressure regulating unit). The APC valve 17 can perform vacuum exhaust and stop vacuum exhaust in the processing chamber 6 by opening and closing the valve while the vacuum pump 18 is in operation. Furthermore, the valve opening is adjusted based on the pressure information detected by the pressure sensor 16 while the vacuum pump 18 is in operation, thereby adjusting the pressure in the processing chamber 6. The exhaust system is mainly composed of the exhaust pipe 15, the APC valve 17, and the pressure sensor 16. It is also conceivable to include the vacuum pump 18 in the exhaust system.

[0032] A cover 19 is provided below the manifold 5, serving as a furnace port cover that airtightly closes the lower end opening of the manifold 5. Cover 19 is formed of a metal such as stainless steel or a nickel-based alloy and is disk-shaped. An O-ring 19A, serving as a sealing member and contacting the lower end of the manifold 5, is provided on the top surface of cover 19.

[0033] In addition, a cover plate 20 for protecting the cover 19 is provided on the upper surface of the cover 19 on the inner side of the bottom flange of the manifold 5. The cover plate 20 is made of a heat-resistant and corrosion-resistant material such as quartz, sapphire or SiC, and is formed in the shape of a disk. The cover plate 20 does not require mechanical strength and can therefore be formed to a relatively thin thickness. The cover plate 20 is not limited to a component prepared independently of the cover 19, but may also be a thin film or layer of a nitride or the like coated on the inner surface of the cover 19 or the inner surface modified. The cover plate 20 may also have a wall rising from the edge of the circumference along the inner surface of the manifold 5.

[0034] The wafer boat 21, serving as a substrate holder, supports multiple wafers 7, for example, 25 to 200 wafers 7, arranged in a horizontal position and aligned vertically in multiple layers. The wafers 7 are arranged at regular intervals. The wafer boat 21 is made of a heat-resistant material such as quartz or SiC. It is sometimes preferable that the reaction tube 4 have a minimum inner diameter sufficient to safely load and unload the wafer boat 21.

[0035] A thermal insulation structure 22 is located below the wafer boat 21 in the processing chamber 6 and connected to the exhaust pipe 15. The thermal insulation structure 22 has a structure that minimizes heat conduction or transfer in the vertical direction and typically has a cavity inside. As described in detail later, the thermal insulation structure 22 is configured to prevent radiant heat from above from escaping toward the lower portion of the reaction tube 4. Furthermore, the interior of the thermal insulation structure 22 can be purged with a purge gas.

[0036] A rotating mechanism 23 for rotating the wafer boat 21 is provided on the side of the cover 19 opposite the processing chamber 6. A gas supply pipe 24 for purge gas is connected to the rotating mechanism 23. The gas supply pipe 24 is provided with an MFC 25 and a valve 26 in order from the upstream direction, which mainly constitute the purge gas supply unit. One of the purposes of this purge gas is to protect the interior of the rotating mechanism 23 (such as the bearings) from the effects of corrosive gases used in the processing chamber 6. The purge gas is discharged from the rotating mechanism 23 along the axis and is guided into the thermal insulation structure 22.

[0037] The boat elevator 27 is vertically disposed outside the reaction tube 4 and functions as an elevator mechanism (transport mechanism) for raising and lowering the lid 19. Thus, the boat 21 and wafers 7 supported by the lid 19 are carried in and out of the processing chamber 6.

[0038] A temperature detector 28 is provided on the outer wall of the reaction tube 4. The temperature detector 28 may be composed of a plurality of thermocouples arranged vertically. The power supply to the heater 3 is adjusted based on the temperature information detected by the temperature detector 28, thereby achieving the desired temperature distribution within the processing chamber 6.

[0039] The controller 29 is a computer that controls the entire substrate processing device 1, and is electrically connected to MFC10, 13, 25, valves 11, 14, 26, pressure sensor 16, APC valve 17, vacuum pump 18, heater 3, the auxiliary heater as the second heater described later, namely the cover heater 34, temperature detector 28, rotating mechanism 23, wafer boat elevator 27, etc., and receives signals from them or controls them.

[0040] Figure 2 The figure shows a cross-section of the heat-insulating structure 22 and the rotating mechanism 23. The rotating mechanism 23 includes a housing (main body) 23A, which is formed into a roughly cylindrical shape with an open upper end and a closed lower end. The housing 23A is fixed to the lower surface of the cover 19 by bolts. Inside the housing 23A, a cylindrical inner shaft 23B and an outer shaft 23C are coaxially arranged in order from the inside. The outer shaft 23C is formed into a cylindrical shape with a diameter larger than the diameter of the inner shaft 23B. The outer shaft 23C is rotatably supported by a pair of upper and lower inner bearings 23D and 23E sandwiched between the inner shaft 23B and the housing 23A, and a pair of upper and lower outer bearings 23F and 23G sandwiched between the housing 23A. On the other hand, the inner shaft 23B is fixed to the housing 23A and cannot rotate.

[0041] Magnetic fluid seals 23H and 23I are installed on the inner bearing 23D and outer bearing 23F, that is, on the side of the processing chamber 6. Magnetic fluid seals 23H and 23I separate the vacuum and atmospheric pressure air. A worm gear or pulley 23K driven by an electric motor (not shown) is mounted on the outer shaft 23C.

[0042] The sub-heater support 33 is vertically inserted through the inner side of the inner shaft 23B. The sub-heater support 33 is a quartz tube, and a cover heater 34, serving as a sub-heater for heating the wafer 7 from below within the processing chamber 6, is concentrically held at its upper end. The sub-heater support 33 is supported at the upper end of the inner shaft 23B by a support portion 23N formed of a heat-resistant resin. Furthermore, at the lower end, the sub-heater support 33 is sealed between its outer surface and the inner shaft 23B via an O-ring via a vacuum joint 23P connected to the inner shaft 23B or the housing 23A.

[0043] A cylindrical rotating shaft 36 with a flange at its lower end is fixed to the upper surface of the flanged outer shaft 23C. The sub-heater support 33 extends through the hollow of the rotating shaft 36. A disc-shaped rotating table 37 is fixed to the upper end of the rotating shaft 36, spaced a predetermined distance from the cover plate 20. The rotating table 37 has a through-hole formed in its center, through which the sub-heater support 33 extends.

[0044] The rotating table 37 is formed of metal such as stainless steel, etc. A heat shield plate holder 38 holding a plurality of heat shield plates 40 and a cylindrical cover (lid) 39 are concentrically placed on the upper surface of the rotating table 37 and fixed with screws or the like.

[0045] The lid heater 34 is provided below the wafer boat 21 and closer to the lid 19 than the wafer boat 21 , and heats the interior of the reaction tube 4 .

[0046] like Figure 2 and Figure 3 As shown, the cover heater 34 is formed into a circular ring with a diameter smaller than that of either the wafer 7 or the cover 39, and is connected and supported by the sub-heater support 33 so as to be parallel to the wafer 7. A heating wire constituting a coiled resistance heating element, namely a heating element 34B, is inserted into each of the sub-heater support 33. The heating element 34B is formed of, for example, an Fe-Cr-Al alloy, molybdenum disilicide, or tungsten.

[0047] The cover heater 34 has independent wires and can be energized independently. The cover heater 34 is arranged near the upper end of the insulation structure 22. In addition, a plurality of insulation plates 40 are arranged below the cover heater 34. Furthermore, the cover heater 34 heats the upper surface of the cover body 39 located around it, the insulation plates 40A, and the wafer 7 (bottom wafer) located at the bottom layer of the wafer boat 21. The cover heater 34 performs the following two functions: heating to compensate for the heat escaping from the furnace mouth so that the apparent insulation of the insulation structure 22 becomes very high; and uniformizing the in-plane temperature distribution of the bottom wafer. The former helps to uniformize the temperature between the wafers 7. By performing this heating during the temperature rise process, it is possible to approach the temperature distribution (temperature gradient distribution) in a steady state where the temperature is stabilized, thereby accelerating the convergence of the temperature control of the heater 3.

[0048] like Figure 2 As shown, a heat absorber 56 having a predetermined emissivity is provided on the upper surface of the flange 4C, that is, on the side opposite the manifold 5. Preferably, the heat absorber 56 has an emissivity close to unity (i.e., close to that of a blackbody) in at least a portion of the wavelength range between the peak wavelength of blackbody radiation at the heat-resistant temperature of the O-ring 5A and the peak wavelength of blackbody radiation at the temperature of the center of the reaction tube 4. The heat absorber 56 absorbs radiant heat near the flange 4C before light entering the reaction tube 4 reaches the O-ring 5A through multiple reflections, etc. This protects the O-ring 5A between the flange 4C and the manifold 5 from the effects of heat. Preferably, the heat absorber 56 is in close contact with the flange 4C and can be formed as a thin, elastic sheet. Alternatively, the heat absorber 56 can be sandwiched between the flange 4C and a backing plate (not shown) that presses the flange 4C against the manifold 5, acting as a cushion.

[0049] Furthermore, a thermal insulation cloth 51 is installed on the outer circumference of the reaction tube 4, above the flange 4C and between the lid 19-side end of the furnace 2. Furthermore, a thermal insulation sheet 53 is wrapped around the outer surface of the thermal insulation cloth 51. The thermal insulation cloth 51 and thermal insulation sheet 53 prevent the intrusion of radiant heat from outside the reaction tube 4, thereby stabilizing the temperature within the furnace. This is useful when adjacently arranging other reaction tubes 4 that may be used at different temperatures. Furthermore, it prevents heat from escaping from the furnace, where the temperature of the bottom wafer is prone to drop, improving thermal insulation performance and shortening the temperature stabilization time.

[0050] The thermal insulation sheet 53 is made of a high-reflectivity (low-emissivity) metal such as molybdenum (Mo). A flat, mirror-like surface can reduce vertical emissivity. Alternatively, the sheet can be a laminate of a metal film and a resin film thick enough to not transmit infrared rays. The sheet can also be wound in more than one layer.

[0051] Next, the structure of the heat insulating structure 22 will be described using the drawings.

[0052] The thermal insulation structure 22 is composed of a thermal insulation holder 38, a cover 39, and a plurality of thermal insulation panels 40, and is placed on a turntable 37. The thermal insulation structure 22 is positioned near the furnace opening, which has a temperature gradient, between the wafer boat 21 and the lid 19 within the processing chamber 6. More specifically, the end of the thermal insulation structure 22 on the deep side of the reaction tube 4 is preferably positioned closer to the deep side of the reaction tube 4 than the end on the lid 19 side of the furnace 2.

[0053] The heat shield retainer 38 is cylindrical in shape, with a central cavity through which the subheater support 33 passes. The heat shield retainer 38 is arranged approximately coaxially with the axis of arrangement of the heat shields 40 and holds a plurality of disc-shaped heat shields 40. The cylindrical portion 38A of the heat shield retainer 38 is provided with a plurality of flange-shaped retaining portions 38D for holding the heat shields 40. Furthermore, the lower end of the heat shield retainer 38 has outward-facing flange-shaped legs 38C. The lower ends of the legs 38C abut against the rotating table 37. The heat shield retainer 38 can be formed from a heat-resistant material such as quartz.

[0054] A plurality of heat insulation panels 40 are arranged at intervals from each other in the heat insulation panel holder 38. That is, the heat insulation structure 22 is formed by arranging a plurality of heat insulation panels 40 at intervals from each other.

[0055] On the other hand, the upper end of the heat insulator holder 38 is opened so that the sub-heater support 33 protrudes therefrom, and constitutes a purge gas supply port 38B.

[0056] A first flow path having an annular cross section is formed between the heat shield plate holder 38 and the sub-heater support 33 as a purge gas supply path for supplying purge gas to an upper portion of the heat shield structure 22 .

[0057] The purge gas supplied from the supply holes 38B flows downward in the second flow path, which is the space between the heat shield holder 38 and the inner wall of the cover 39 , and is discharged outside the cover 39 from a plurality of exhaust holes 22A provided at the lower end of the cover 39 .

[0058] The upper end of the cover 39 is sealed by a flat plate, and the wafer boat 21 is placed there. The upper end of the cover 39 is convex. In other words, a step is formed around the entire perimeter of the upper surface of the cover 39, and the annular bottom plate of the wafer boat 21 fits into this step. This structure allows the cover 39 and wafer boat 21 to be rotated without rotating the cover heater 34.

[0059] The portion above the step on the upper surface of the cover 39 is not loaded by the wafer boat 21 and can therefore be thinner and formed into any shape. For example, shaping or opacification such as adjusting the heating amount of the bottom wafer can be performed.

[0060] The cover body 39 is made of quartz or ceramics, is arranged approximately coaxially with the arrangement axis of the heat insulation plates 40, and is configured to cover the side surfaces and upper surfaces of multiple heat insulation plates 40. In addition, a cylindrical side heat insulation material 54 is embedded in the side surface of the cover body 39. The side heat insulation material 54 is, for example, configured in the form of a sheet. Specifically, it has metal sheets such as molybdenum (Mo) sheets and platinum (sheets), and ceramic sheets such as aluminum oxide (AlO) and zirconium oxide (ZrO). It is preferably composed of a Mo sheet. More preferably, the surface of the side heat insulation material 54 is configured as a mirror surface. By configuring the surface as a mirror surface, the reflectivity can be increased, and the heat insulation effect can be improved.

[0061] like Figure 4 (A) and Figure 4 As shown in FIG. 3B , a heat shield 40A and a heat shield 40B are coaxially provided on a holding portion 38D of a heat shield holder 38 as the heat shield 40. The heat shield 40A and the heat shield 40B are held at a predetermined distance from each other in the heat shield holder 38. The heat shield 40A is held on the uppermost layer of the heat shield holder 38, i.e., on the side where the cover heater 34 is disposed, and the heat shield 40B is held below the heat shield.

[0062] The heat shield 40B is provided with a radially elongated notch 40C. The width of the notch 40C is set to be smaller than the outer diameter of the retaining portion 38D of the heat shield retainer 38, allowing it to be retained by the retaining portion 38D. It is also set to be slightly larger than the outer diameter of the cylindrical portion 38A of the heat shield retainer 38, allowing it to avoid the cylindrical portion 38A of the heat shield retainer 38. Furthermore, the length of the notch 40C is set to be greater than the radius of the heat shield 40B by the width of the notch. Furthermore, when inserted into the retaining portion 38D, the notches 40C of each layer of the heat shield 40B are circumferentially staggered so that they do not overlap. This circumferential staggering of the notches 40C of each layer of the heat shield 40B can mitigate any adverse effects of the notches 40C in each layer of the heat shield 40B. Furthermore, since the through holes 50A (described later) of each layer are not arranged in a straight line, light passing through the through holes 50A is easily reflected by the heat insulating plate 40B of the lower layer, thereby improving the heat insulating property.

[0063] The heat shield 40A has a hole 40D formed in the center thereof. The diameter of the hole 40D is set to be smaller than the outer diameter of the holding portion 38D so that the heat shield can be held by the holding portion 38D of the heat shield holder 38. By forming the circular hole 40D in the heat shield 40A instead of forming the notch 40C as in the heat shield 40B, the heating of the bottom wafer can be uniformed.

[0064] The inner diameter of 40D is smaller than the inner diameter of the cover heater 34 (for example, half or less).

[0065] The heat shields 40A and 40B are disk-shaped, smaller than the diameter of the wafers 7 and larger (e.g., 1.5 times or more) than the outer diameter of the cover heater 34, to accommodate the housing 39. The heat shields 40A and 40B form a suitable vertical temperature gradient within the insulation structure 22. The heat shield 40A reflects radiant heat from the heater 3 and the cover heater 34, trapping heat above the heat shield 40A, and flattening the in-plane temperature distribution of the wafers 7 placed on the bottom layer of the wafer boat 21.

[0066] In this example, the number of thermal insulation plates 40B is set to be greater than the number of thermal insulation plates 40A. By placing thermal insulation plates 40A above and thermal insulation plates 40B below, thermal insulation can be achieved by reflecting radiant heat from cover heater 34 using thermal insulation plates 40A. Furthermore, by using thermal insulation plates 40B to reflect light radiated from or transmitted through thermal insulation plates 40A and 40B at locations away from wafer 7, thermal insulation can be achieved. This improves the temperature responsiveness of wafer 7 and shortens the temperature rise time. Furthermore, the number and arrangement of thermal insulation plates 40A and 40B are not limited to those described above and can be optimized to minimize heat flux through thermal insulation structure 22.

[0067] Next, take the heat shield 40B as an example, use Figure 5 (A) Figure 5 (B) Figure 6 (A) and Figure 6 (B) The structure of the heat insulating board 40 constituting the heat insulating structure 22 suitable for use in the embodiment of the present invention will be described. Figure 6 (A) and Figure 6 (B) is a longitudinal sectional view schematically showing a part of the heat shielding plate 40B.

[0068] The heat shield 40B is composed of a heat insulating material 50 and a pair of sealing plates 52A and 52B. Sealing plates 52A and 52B are disc-shaped with the same diameter and cooperate to form a sealing member. The heat insulating material 50 is thinner than either sealing plate 52A or 52B and has a slightly smaller outer diameter than the sealing plates 52A and 52B.

[0069] The heat insulating material 50 is, for example, in the form of a sheet. Specifically, it comprises metal sheets such as molybdenum (Mo) sheets and platinum (sheets), and ceramic sheets such as aluminum oxide (AlO) and zirconium oxide (ZrO). It is preferably composed of Mo sheets. More preferably, the surface of the heat insulating material 50 is configured as a mirror surface. By configuring the surface as a mirror surface, the reflectivity can be increased, and the heat insulating effect can be improved. In addition, a plurality of square through holes 50A connecting the front and back surfaces are formed in the heat insulating material 50. In addition, the through hole 50A may also be circular.

[0070] The sealing plates 52A and 52B are made of a heat-resistant and corrosion-resistant material such as quartz or ceramic, and have a rigidity that does not bend due to their own weight and a strength that can withstand a pressure difference of more than 1 atmosphere. On at least one of the sealing plates 52A and 52B, protrusions 58A and 58B that are the same shape as the through-hole 50A and slightly smaller than the through-hole 50A are respectively formed at positions corresponding to the through-hole 50A of the heat insulating material 50. In addition, on at least one of the sealing plates 52A and 52B, side walls 59A and 59B that are the same height as the protrusions 58A and 58B are provided throughout the entire circumference of the edge including the notch 40C. The protrusions 58A and 58B are aligned with each other and arranged regularly (for example, in a grid shape), and their formation density can be selected from 0.1 to 10 cm -2 .

[0071] like Figure 6 (A) and Figure 6As shown in (B), the heat insulation plate 40B is formed by a pair of sealing plates 52A and 52B sandwiching the heat insulation material 50. Specifically, any one of the protrusions 58A and 58B of the sealing plates 52A and 52B is inserted into the through hole 50A, and heat treatment is applied while vacuuming to perform bonding, thereby bonding the side walls 59A and 59B, the protrusions 58A and the protrusions 58B to each other, thereby forming the heat insulation plate 40B. At this time, the heat insulation material 50 can form a vacuum insulation layer on both sides without being welded to the sealing plates 52A and 52B. Heat treatment (welding), laser welding, vacuum bonding, etc. can be used to integrate the pair of sealing plates 52A and 52B. In addition, vacuuming can also be performed after welding. In this case, a thin tube for sealing protrudes vertically from either side of the sealing plates 52A and 52B, and remains as a navel after sealing. In such a case Figure 4 When stacked as shown, if the stacking interval is set to be at least twice the height of the navel, contact with the navel can be avoided by aligning the direction of the notches 40C of the adjacent heat shielding panels 40B with the position of the navel.

[0072] That is, the heat insulating plate 40B is provided with the heat insulating material 50 in the vacuum cavity 60 formed between the pair of sealing plates 52, and the columns erected between the pair of sealing plates 52 are arranged in a predetermined pattern in the cavity 60, so that the strength can be maintained. The surfaces of the sealing plates 52A and 52B can be formed into a mirror surface or optically sufficiently flat by flame polishing, and the interior can be made transparent or opaque. If it is made opaque by bubbles, etc., although the strength is reduced, the heat flux generated by the transmission and conduction of radiation can be reduced. In order to suppress the radiation that passes through the protrusions 58A, 58B (columns) or the side walls 59A and 59B, the outer surface of the heat insulating plate 40B can be made into a sandblasted surface or the interior can be made opaque only in these parts. In addition, the heat insulating material 50 and either of the sealing plates 52A and 52B can be in point contact instead of surface bonding. For example, the heat insulating material 50 embossed on both surfaces is supported by the sealing plate 52B serving as the bottom of the cavity 60 through point contact by the tips of the downward protrusions.

[0073] Similarly, vacuum cavities are formed inside the heat insulating plate 40A and the side surfaces of the cover 39 , and the heat insulating material 50 or the side heat insulating material 54 is disposed in each cavity.

[0074] Thus, thermal insulation panels 40 having a vacuum cavity 60 formed therein and thermal insulation material 50 within cavity 60 can suppress heat conduction in the thickness direction compared to thermal insulation panels without cavity 60, thereby improving the thermal insulation performance of each panel. Furthermore, by providing side insulation material 54 on the side of cover 39, not only is the thermal insulation performance between the interior and exterior of insulation structure 22 enhanced, but the thermal insulation performance between thermal insulation panels 40 is also improved due to the reduced form factor. Furthermore, the portion of side insulation material 54 above thermal insulation panel 40A reflects radiant heat from lid heater 34 toward wafer 7, preventing it from escaping toward the lower portion of processing chamber 6.

[0075] like Figure 7 As shown, controller 29 is electrically connected to various components, including MFCs 10, 13, and 25, valves 11, 14, and 26, pressure sensor 16, APC valve 17, vacuum pump 18, heater 3, lid heater 34, temperature detector 28, rotation mechanism 23, and boat elevator 27, and automatically controls these components. Controller 29 is configured as a computer and includes a CPU (Central Processing Unit) 212, RAM (Random Access Memory) 214, storage device 216, and I / O port 218. RAM 214, storage device 216, and I / O port 218 are configured to exchange data with CPU 212 via an internal bus 220. I / O port 218 is connected to each of the aforementioned components. An input / output device 222, such as a touch panel, is connected to controller 29.

[0076] The storage device 216 is comprised of, for example, a flash memory or a hard disk drive (HDD). The storage device 216 readablely stores a control program for controlling the operation of the substrate processing apparatus 1 and programs (recipes such as program recipes and cleaning recipes) for causing each component of the substrate processing apparatus 1 to perform film formation processing according to processing conditions. The RAM 214 serves as a memory area (work area) for temporarily storing programs and data read by the CPU 212.

[0077] The CPU 212 reads and executes a control program from the storage device 216 , and reads a recipe from the storage device 216 according to input of an operation instruction from the input / output device 222 or the like, and controls each structure according to the recipe.

[0078] The controller 29 can be configured by installing the aforementioned program, which is continuously stored in an external storage device (e.g., a semiconductor memory such as a USB memory or memory card, an optical disk such as a CD or DVD, or an HDD) 224, into a computer. The storage device 216 and the external storage device 224 are configured as tangible computer-readable media. Hereinafter, these are collectively referred to as storage media. Furthermore, the program can be provided to the computer using a communication means such as the Internet or a dedicated line, rather than using the external storage device 224.

[0079] Next, as one step in the manufacturing process of a semiconductor device (equipment), a description will be given of an example of a process for forming a film on a substrate (hereinafter also referred to as a film forming process) using the substrate processing apparatus 1 described above.

[0080] Here, the following example is described: two or more nozzles 8 are provided, hexachlorodisilane (HCDS) gas is supplied from nozzle 8a as a first process gas (raw material gas), and ammonia (NH3) gas is supplied from nozzle 8b as a second process gas (reaction gas), to form a silicon nitride (SiN) film on wafer 7. In the following description, the operation of each component of substrate processing apparatus 1 is controlled by controller 29.

[0081] In the film formation process of this embodiment, a SiN film is formed on wafer 7 by repeating the following steps a predetermined number of times (one or more): a step of supplying HCDS gas to wafer 7 in process chamber 6; a step of removing HCDS gas (residual gas) from process chamber 6; a step of supplying NH3 gas to wafer 7 in process chamber 6; and a step of removing NH3 gas (residual gas) from process chamber 6. In this specification, for convenience, this film formation sequence is expressed as follows:

[0082]

[0083] (Wafer loading and wafer boat loading)

[0084] When multiple wafers 7 are loaded into the wafer boat 21 (wafer loading), the wafer boat 21 is moved into the processing chamber 6 (wafer loading) by the wafer boat elevator 27. At this time, the cover 19 is in an airtightly closed (sealed) state at the lower end of the manifold 5 via the O-ring 19A. From the standby state before wafer loading, the valve 26 can be opened to supply a small amount of purge gas into the cover 39.

[0085] (Pressure adjustment)

[0086] The space within processing chamber 6, i.e., where wafers 7 are located, is evacuated (decompressed) by vacuum pump 18 to a predetermined pressure (vacuum level). At this time, the pressure within processing chamber 6 is measured by pressure sensor 16, and feedback control of APC valve 17 is performed based on the measured pressure information. The purge gas supply to cover 39 and the operation of vacuum pump 18 are maintained until at least the processing of wafers 7 is completed.

[0087] (Heating)

[0088] After oxygen and the like are fully exhausted from the processing chamber 6, the temperature in the processing chamber 6 is raised. Based on the temperature information detected by the temperature detector 28, the power supply status of the heater 3 and the cover heater 34 is feedback-controlled so that the processing chamber 6 has a predetermined temperature distribution suitable for film formation. The heater 3 and the cover heater 34 continue to heat the processing chamber 6 at least until the processing (film formation) of the wafer 7 is completed. The power supply period of the cover heater 34 does not have to coincide with the heating period of the heater 3. For example, it is desirable that the temperature of the cover heater 34 reaches the same temperature as the film formation temperature immediately before the film formation begins, and that the inner surface temperature of the manifold 5 reaches 180°C or higher (for example, 260°C). Heating immediately before the start of the film formation can shorten the time that the O-ring 19A is exposed to high temperature, thereby extending its life.

[0089] Furthermore, the rotation mechanism 23 begins rotating the wafer boat 21 and wafers 7. The rotation mechanism 23 rotates the wafer boat 21 via the rotation shaft 36, the rotation stage 37, and the cover 39, thereby rotating the wafers 7 without rotating the cover heater 34. This reduces uneven heating. The rotation mechanism 23 continues rotating the wafer boat 21 and wafers 7 until at least the processing of the wafers 7 is completed.

[0090] (Film Formation)

[0091] When the temperature in the processing chamber 6 is stabilized at the preset processing temperature, steps 1 to 4 are repeated. In addition, the valve 26 may be opened before starting step 1 to increase the supply of the purge gas.

[0092] [Step 1: Raw material gas supply process]

[0093] In step 1, HCDS gas is supplied to wafer 7 within processing chamber 6. Simultaneously with the opening of valve 11a, valve 14a is opened, allowing HCDS gas to flow into gas supply pipe 9a and N₂ gas to flow into gas supply pipe 12a. The HCDS gas and N₂ gas have their flow rates regulated by MFCs 10a and 13a, respectively, and are supplied into processing chamber 6 through nozzle 8a and exhausted through exhaust pipe 15. By supplying HCDS gas to wafer 7, a silicon (Si)-containing film having a thickness of, for example, less than one atomic layer to several atomic layers is formed as a first layer on the outermost surface of wafer 7.

[0094] [Step 2: Raw material gas exhaust process]

[0095] After the first layer is formed, valve 11a is closed to stop the supply of HCDS gas. APC valve 17 remains open, and vacuum pump 18 evacuates the processing chamber 6, discharging any remaining unreacted HCDS gas or any HCDS gas that has been involved in the formation of the first layer. Furthermore, valve 14a remains open, and N2 gas is supplied to purge the gas supply pipe 9a and the nozzle processing chamber 6.

[0096] [Step 3: Reaction Gas Supply Process]

[0097] In step 3, NH3 gas is supplied to the wafer 7 in the processing chamber 6. The opening and closing control of valves 11b and 14b is performed in the same order as the opening and closing control of valves 11a and 14a in step 1. The flow rates of NH3 gas and N2 gas are adjusted by MFCs 10b and 13b, respectively, and they are supplied to the processing chamber 6 through nozzles 8b and exhausted from exhaust pipes 15. The NH3 gas supplied to the wafer 7 reacts with at least a portion of the first layer, i.e., the Si-containing layer, formed on the wafer 7 in step 1. Thus, step 3 is completed.

[0098] One layer is nitrided and changed (modified) into a second layer containing Si and N, namely a silicon nitride layer (SiN layer).

[0099] [Step 4: Reaction Gas Exhaust Process]

[0100] After the second layer is formed, valve 11b is closed to stop the supply of NH3 gas. Then, the unreacted NH3 gas and reaction by-products remaining in the processing chamber 6 or after the second layer is formed are exhausted from the processing chamber 6 through the same processing sequence as step 2.

[0101] By performing the above four steps non-simultaneously, that is, without overlapping, for a predetermined number of times (n), a SiN film of a predetermined composition and predetermined thickness can be formed on the wafer 7. Preferably, the above cycle is repeated a plurality of times.

[0102] The following are examples of processing conditions for the above sequence:

[0103] Processing temperature (wafer temperature): 250~700℃,

[0104] Processing pressure (pressure in the processing chamber): 1~4000Pa;

[0105] HCDS gas supply flow rate: 1-2000 sccm;

[0106] NH3 gas supply flow rate: 100~10000sccm;

[0107] N2 gas supply flow rate (nozzle): 100~10000sccm;

[0108] N2 gas supply flow rate (rotation axis): 100~500sccm.

[0109] By setting each processing condition to a value within the respective range, the film formation process can be accurately performed.

[0110] Thermally decomposable gases such as HCDS are more likely to form byproduct films on metal surfaces than on quartz. Surfaces exposed to HCDS (and ammonia) are more likely to form SiO, SiON, etc., when exposed to temperatures below 260°C.

[0111] (Purification and atmospheric pressure restoration)

[0112] After the film formation process is completed, valves 14a and 14b are opened to supply N2 gas from gas supply pipes 12a and 12b into the processing chamber 6 and exhaust it from exhaust pipe 15. As a result, the atmosphere in the processing chamber 6 is replaced with an inert gas (inert gas replacement), and the remaining raw materials and by-products are removed (purified) from the processing chamber 6. Then, the APC valve 17 is closed until the pressure in the processing chamber 6 reaches normal pressure, and then N2 gas is filled in (restoration of atmospheric pressure).

[0113] (Wafer boat unloading and wafer unloading)

[0114] The lid 19 is lowered by the boat elevator 27, opening the lower end of the manifold 5. The processed wafers 7 are then unloaded from the lower end of the manifold 5 to the outside of the reaction tube 4 while being supported by the boat 21 (boat unloading). The processed wafers 7 are removed from the boat 21.

[0115] In this embodiment, one or more of the following effects can be obtained.

[0116] (a) By forming a vacuum cavity inside the heat insulating plate 40 and burying a heat insulating material with high reflectivity in the cavity, radiant heat can be reflected, thereby improving the heat insulating performance in the processing chamber.

[0117] (b) This can shorten the temperature stabilization time in the processing chamber and improve the in-plane uniformity of the wafer.

[0118] (c) Specifically, by placing the heat insulating plate 40 with a vacuum cavity formed inside and the heat insulating material 50 buried in the cavity below the cover heater 34, the radiant heat of the cover heater 34 can be retained in the furnace, thereby suppressing heat escape from the lower part of the processing chamber 6.

[0119] (d) Furthermore, by providing side heat insulators 54 on the side surfaces of cover 39 covering heat insulating plate 40 , radiant heat from lid heater 34 can be reflected toward wafer 7 , preventing it from escaping to the lower portion of processing chamber 6 .

[0120] (e) Furthermore, by wrapping a heat-insulating cloth 51 around the furnace opening of the reaction tube 4 and further covering it with a heat-insulating sheet 53, the heat-insulating performance of areas where the temperature of the bottom wafer is likely to drop can be improved, thereby shortening the temperature stabilization time within the processing chamber. Furthermore, radiant heat from the outside into the furnace can be reflected, thereby stabilizing the temperature within the furnace.

[0121] (f) Furthermore, by providing the heat absorber 56 on the upper surface of the flange portion 4C, radiant heat in the vicinity of the flange portion 4C can be absorbed, thereby protecting the sealing member between the flange portion 4C and the manifold 5 .

[0122] (g) Furthermore, the heat insulation performance can be improved by using the same number of sheets as in the past. Furthermore, the number of heat insulation panels 40 can be reduced significantly while maintaining the same heat insulation performance as in the past.

[0123] In addition, those skilled in the art should understand that the heat insulating material of the quartz cover in the above embodiment is arranged above the uppermost heat insulating plate, and can be omitted or replaced by opaque quartz below it.

[0124] In addition, those skilled in the art will appreciate that a plurality of heat insulating materials 50 may be stacked and disposed in the cavity 60 of the heat insulating plate 40 .

[0125] Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the present invention.

[0126] Explanation of symbols

[0127] 1—substrate processing device, 2—furnace, 3—heater, 4—reaction tube, 6—processing chamber, 7—wafer (substrate), 21—crystal boat (substrate holder), 22—thermal insulation structure, 29—controller, 34—lid heater (sub-heater), 40—thermal insulation board, 50—thermal insulation material, 51—thermal insulation cloth, 52—sealing plate, 53—thermal insulation sheet, 54—side insulation material, 56—heat absorber.

Claims

1. A heat-insulating structure arranged near a furnace opening having a temperature gradient in a heat treatment furnace. It is characterized in that A plurality of heat-insulating plates are provided, each of which comprises a metal heat-insulating material and a quartz or ceramic sealing member covering the front and back surfaces of the heat-insulating material, wherein the heat-insulating material is arranged in a vacuum cavity formed inside the sealing member. The plurality of heat insulation panels are arranged at intervals from each other. The sealing member is composed of a pair of sealing plates. The pair of sealing plates are connected to each other along their entire circumferences. Each of the plurality of heat insulating plates has at least one through-hole communicating between the front and back surfaces, and the pair of sealing plates are connected to each other along the entire circumference of the pair of sealing plates and within the through-holes.

2. The thermal insulation structure according to claim 1, wherein The pair of sealing plates are formed into a disc shape. The heat insulating material is formed to be thinner than either of the pair of sealing plates.

3. The thermal insulation structure according to claim 1, wherein Each of the heat insulating materials of the plurality of heat insulating panels has a mirror surface.

4. The thermal insulation structure according to claim 1, wherein The heat insulating material of each of the plurality of heat insulating panels is supported in the cavity so as not to come into surface contact with the pair of sealing plates.

5. The thermal insulation structure according to claim 1, wherein Each of the heat insulating materials of the plurality of heat insulating panels has a plurality of regularly arranged through holes.

6. The thermal insulation structure according to claim 1, wherein The pair of sealing plates have rigidity such that they do not bend due to their own weight, and have mirror-like surfaces except for at least the portions where they are connected to each other.

7. The thermal insulation structure according to claim 6, characterized in that The heat insulating material of each of the plurality of heat insulating panels is embossed.

8. The thermal insulation structure according to claim 1, wherein Also features: a heat shield plate holder disposed substantially coaxially with an arrangement axis of the plurality of heat shield plates and configured to hold the plurality of heat shield plates; and The cylindrical cover is provided substantially coaxially with the arrangement axis, covers the plurality of heat shielding plates, and is made of quartz or ceramic. The cover has a side surface in which a cylindrical side heat insulating material is embedded.

9. The thermal insulation structure according to claim 1, wherein The above-mentioned heat insulating material is made of molybdenum.

10. A substrate processing device, characterized in that: have: a cylindrical processing container in which substrates are processed; a substrate holder for holding the substrate in the processing container; a processing gas supply unit for supplying processing gas into the processing container; a cylindrical first heater disposed outside the processing container and heating the inside of the processing container; a cover disposed at one end of the processing container; a second heater disposed closer to the cover than the substrate holder and configured to heat the interior of the processing container; a heat insulating cloth provided on the outer periphery of the processing container between the cover-side end of the first heater and the cover; a heat-insulating sheet wound around the outside of the heat-insulating cloth; and The heat-insulating structure is arranged near the furnace opening in the above-mentioned processing container. The thermal insulation structure is formed by arranging a plurality of thermal insulation boards at intervals from each other, wherein the thermal insulation boards include a metal thermal insulation material and a quartz or ceramic sealing member covering the front and back surfaces of the thermal insulation material, and the thermal insulation material is arranged in a vacuum cavity formed inside the sealing member. An end of the heat insulating structure farther from the cover is arranged at a deeper side of the processing container than an end of the first heater on the cover side.

11. The substrate processing apparatus according to claim 10, wherein: The processing container is composed of a reaction tube, and at least a portion of the reaction tube surrounded by the first heater is formed of a material that transmits infrared rays. The reaction tube has a flange portion connected to the counterpart member on the cover side via a sealing member. A heat absorbing body having a predetermined emissivity is provided on a surface of the flange portion on the opposite side to the counterpart member on the cover side.

12. The substrate processing apparatus according to claim 10, wherein: The above-mentioned heat insulation sheet is made of molybdenum.

13. A method for manufacturing a semiconductor device, characterized in that: The process includes the following steps: A heat insulating structure is disposed near a furnace port having a temperature gradient in a heat treatment furnace, wherein the heat insulating structure is formed by arranging heat insulating plates at intervals, the heat insulating plates comprising a metal heat insulating material and a quartz or ceramic sealing member covering the front and back surfaces of the heat insulating material, wherein the heat insulating material is disposed in a vacuum cavity formed within the sealing member; placing the substrate to be processed into the heat treatment furnace; Performing vacuum exhaust on the heat treatment chamber; and While being insulated by the above-mentioned heat insulation structure, the heat treatment furnace is heated. The sealing member is composed of a pair of sealing plates. The pair of sealing plates are connected to each other along their entire circumferences. Each of the plurality of heat insulating plates has at least one through-hole communicating between the front and back surfaces, and the pair of sealing plates are connected to each other along the entire circumference of the pair of sealing plates and within the through-holes.

14. A substrate processing method, characterized in that: The process includes the following steps: A heat insulating structure is disposed near a furnace port having a temperature gradient in a heat treatment furnace, wherein the heat insulating structure is formed by arranging heat insulating plates at intervals, the heat insulating plates comprising a metal heat insulating material and a quartz or ceramic sealing member covering the front and back surfaces of the heat insulating material, wherein the heat insulating material is disposed in a vacuum cavity formed within the sealing member; placing the substrate to be processed into the heat treatment furnace; Performing vacuum exhaust on the heat treatment chamber; and While being insulated by the above-mentioned heat insulation structure, the heat treatment furnace is heated. The sealing member is composed of a pair of sealing plates. The pair of sealing plates are connected to each other along their entire circumferences. Each of the plurality of heat insulating plates has at least one through-hole communicating between the front and back surfaces, and the pair of sealing plates are connected to each other along the entire circumference of the pair of sealing plates and within the through-holes.

15. A computer-readable storage medium, characterized in that: A program is stored that causes the substrate processing apparatus to execute the following steps via a computer: A heat insulating structure is disposed near a furnace port having a temperature gradient in a heat treatment furnace, wherein the heat insulating structure is formed by arranging heat insulating plates at intervals, the heat insulating plates comprising a metal heat insulating material and a quartz or ceramic sealing member covering the front and back surfaces of the heat insulating material, wherein the heat insulating material is disposed in a vacuum cavity formed within the sealing member; placing the substrate to be processed into the heat treatment furnace; Performing vacuum exhaust on the heat treatment chamber; and While being insulated by the above-mentioned heat insulation structure, the heat treatment furnace is heated. The sealing member is composed of a pair of sealing plates. The pair of sealing plates are connected to each other along their entire circumferences. Each of the plurality of heat insulating plates has at least one through-hole communicating between the front and back surfaces, and the pair of sealing plates are connected to each other along the entire circumference of the pair of sealing plates and within the through-holes.

16. A substrate processing device, characterized in that: have: a cylindrical processing container in which substrates are processed; a heat-insulating structure disposed near the furnace opening in the processing container; and A cover is disposed at one end of the processing container. The thermal insulation structure is formed by arranging a plurality of thermal insulation boards at intervals from each other, wherein the thermal insulation boards include a metal thermal insulation material and a quartz or ceramic sealing member covering the front and back surfaces of the thermal insulation material, and the thermal insulation material is arranged in a vacuum cavity formed inside the sealing member. The sealing member is composed of a pair of sealing plates. The pair of sealing plates are connected to each other along their entire circumferences. Each of the plurality of heat insulating plates has at least one through-hole communicating between the front and back surfaces, and the pair of sealing plates are connected to each other along the entire circumference of the pair of sealing plates and within the through-holes.

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