JP2015191960A - Deposition apparatus, deposition method and reflector unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a reflector from being damaged by thermal stress.SOLUTION: A deposition apparatus includes a deposition chamber where a film is formed on a substrate, a heater for heating the substrate from below, a first reflector unit provided above the deposition chamber, and a gas supply section for supplying process gas to the deposition chamber. The first reflector unit has an annular first reflector, a first slit is provided in the first reflector from the inner peripheral part to the outer peripheral part, and the first reflector is continuous from one end face to the other end face through the first slit with being separated.

Description

  The present invention relates to a film forming apparatus, a film forming method, and a reflector unit.

  Conventionally, in a manufacturing process of a semiconductor element that requires a relatively large crystal film, such as a power device such as an IGBT (Insulated Gate Bipolar Transistor), a single crystal thin film is formed on a substrate such as a wafer. An epitaxial growth technique for forming a film by vapor phase growth is used.

  In a film forming apparatus used for the epitaxial growth technique, for example, a wafer is placed in a film forming chamber maintained at normal pressure or reduced pressure. And while heating this wafer, the gas used as the raw material for film-forming (henceforth only raw material gas) is supplied in the film-forming chamber. Then, a thermal decomposition reaction and a hydrogen reduction reaction of the source gas occur on the surface of the wafer, and an epitaxial film is formed on the wafer.

  In order to manufacture an epitaxial wafer having a large film thickness with a high yield, it is necessary to improve the vapor deposition rate by bringing new raw material gases into contact with the surface of the uniformly heated wafer one after another. Therefore, epitaxial growth is performed while rotating the wafer at a high speed (for example, see Patent Document 1).

  In the conventional film forming apparatus, in order to increase the thermal efficiency, a donut-shaped (annular) reflector is provided in the upper part of the film forming chamber so as to reflect the radiation from the heat source. For example, carbon coated with SiC is used as the material of the reflector. However, as the temperature of the film forming chamber increases, a temperature distribution occurs in the radial direction of the reflector, and the reflector is damaged due to thermal stress.

JP-A-5-152207

  An object of this invention is to provide the film-forming apparatus provided with the reflector which prevented the damage by the thermal stress, the reflector unit, and the film-forming method using such a film-forming apparatus.

  A film formation apparatus according to an aspect of the present invention includes a film formation chamber that forms a film on a substrate, a heater that heats the substrate from below, a first reflector unit that is provided above the film formation chamber, and the formation device. A gas supply unit configured to supply a process gas to the film chamber, wherein the first reflector unit has an annular first reflector, and the first reflector has a first slit extending from an inner periphery to an outer periphery. The first reflector is continuous without being separated from one end face to the other end face through the first slit.

  In the film forming method according to one aspect of the present invention, a SiC substrate is carried into a film forming chamber provided with a reflector unit at an upper portion, a process gas containing silane gas is taken in from a position above the reflector unit, and penetrates the reflector unit. A film forming method for forming a film on the SiC substrate by supplying the process gas to a lower region of the reflector through a gas flow path, wherein the reflector unit has an annular reflector. The reflector is provided with slits from the inner periphery to the outer periphery, and the reflector is continuous from one end surface to the other end surface via the slit, and is formed on the SiC substrate. In the film forming chamber, the lower area of the reflector unit is set to a first predetermined temperature, and the upper area of the reflector unit is Characterized by the band to the first lower than the predetermined temperature the second predetermined temperature.

  A reflector unit according to an aspect of the present invention is a reflector unit that is provided in an upper part of a film formation chamber for forming a film on a substrate and reflects heat from a heater in the film formation chamber. A first slit is provided from the peripheral part to the outer peripheral part, and the first reflector is continuous from the one end surface through the first slit without being separated from the other end face, and has an annular shape, from the inner peripheral part A second slit is provided over the outer periphery, and the second reflector is continuous without being separated from one end face to the other end face via the second slit, and the second reflector includes the second slit The slit is shifted from the position of the first slit and stacked on the first reflector.

  According to one embodiment of the present invention, the reflector can be prevented from being damaged by thermal stress.

1 is a schematic configuration diagram of a film forming apparatus according to an embodiment of the present invention. The schematic block diagram of the reflector by embodiment of this invention. The schematic block diagram of the reflector unit by embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a film forming apparatus according to an embodiment of the present invention. A substrate 101 made of SiC is used as a sample to be subjected to film formation. FIG. 1 shows a state where the substrate 101 is placed on the susceptor 102. Then, a plurality of types of gases (process gases), which are raw materials for forming the SiC epitaxial film, are supplied onto the substrate 101 placed on the susceptor 102 and subjected to vapor phase growth reaction on the substrate 101 to form a film. I do.

  The film forming apparatus 100 includes a chamber 103 as a film forming chamber in which a SiC epitaxial film is formed by vapor phase growth on a substrate 101.

  A susceptor 102 is provided above the rotating unit 104 inside the chamber 103. The susceptor 102 has a ring shape configured with an opening. The susceptor 102 has a structure in which a counterbore is provided on the inner peripheral side of the susceptor 102 and the outer peripheral portion of the substrate 101 is received and supported in the counterbore. Further, since the susceptor 102 is exposed to a high temperature, for example, the surface of isotropic graphite is configured by coating SiC with high heat resistance and high purity by a CVD method.

  The structure of the susceptor 102 is not limited to that shown in FIG. For example, a susceptor can be configured by providing a member that closes the opening.

  The rotating part 104 has a cylindrical part 104a and a rotating shaft 104b. In the rotating part 104, the susceptor 102 is supported by the upper part of the cylindrical part 104a. Then, when the rotating shaft 104b is rotated by a motor (not shown), the susceptor 102 is rotated through the cylindrical portion 104a. Thus, when the substrate 101 is placed on the susceptor 102, the substrate 101 can be rotated.

  In FIG. 1, a cylindrical portion 104a has a structure in which an upper portion is opened and a structure in which the upper portion is released. A heater (main heater) 120 is provided in the cylindrical portion 104a. As the heater 120, a resistance heater can be used, which is made of, for example, a carbon (C) material doped with impurities. The heater 120 is fed by a wiring (not shown) passing through the inside of a substantially cylindrical quartz shaft 108 provided in the rotating shaft 104b, and heats the substrate 101 from its back surface.

  In addition, in the cylindrical portion 104 a, a reflector 110 is provided below the heater 120 in order to efficiently perform heating by the heater 120. The reflector 110 is made of a material having high heat resistance such as carbon, SiC, or carbon coated with SiC. Further, a heat insulating material 111 is provided below the reflector 110, so that heat from the heater 120 can be prevented from being transmitted to the shaft 108 and the like, and heater power during heating can be suppressed.

  Inside the shaft 108, raising / lowering pins 112 are arranged as substrate raising / lowering means. The lower end of the lifting pin 112 extends to a lifting device (not shown) provided at the lower portion of the shaft 108. And the raising / lowering pin 112 can be raised or lowered by operating the raising / lowering device. The lift pins 112 are used when the substrate 101 is carried into the chamber 103 and carried out of the chamber 103. Lift pins 112 support the substrate 101 from below, lift it up and pull it away from the susceptor 102. Then, the substrate 101 operates so as to be disposed at a predetermined upper position away from the susceptor 102 on the rotating unit 104 so that the substrate 101 can be transferred to and from the robot for transporting the substrate 101 (not shown). .

A gas exhaust part 125 for exhausting gas is provided in the lower part of the chamber 103. The gas exhaust unit 125 is connected to an exhaust mechanism 128 including an adjustment valve 126 and a vacuum pump 127. The exhaust mechanism 128 is controlled by a control mechanism (not shown) to adjust the inside of the chamber 103 to a predetermined pressure.

  In the chamber 103, a cylindrical liner 130 is provided to partition a film formation region 103b where film formation is performed and a side wall (inner wall) 103a of the chamber 103. The liner 130 is configured using a material having high heat resistance such as carbon or carbon coated with SiC.

  An auxiliary heater 131 for heating the substrate 101 from above is provided between the liner 130 and the side wall 103a. The auxiliary heater 131 is, for example, a resistance heating type heater. In addition, a heat insulating material 132 is provided between the auxiliary heater 131 and the side wall 103 a to prevent heat from the auxiliary heater 131 from being transmitted to the chamber 103. Thereby, the heater electric power at the time of a heating can be suppressed.

  Reflector units RU <b> 1 and RU <b> 2 that reflect radiation from the heater 120 and the auxiliary heater 131 are provided on the upper portion of the chamber 103 of the film forming apparatus 100 in order to increase thermal efficiency. The reflector unit RU2 is provided below the reflector unit RU1.

  The reflector unit RU1 includes a plurality of thin plates 140 that are stacked apart from each other, and each thin plate 140 includes a circular reflector 141 and an annular reflector 142 provided on the outer periphery of the circular reflector 141. And have. The reflectors 141 and 142 are configured using carbon, SiC, or carbon coated with SiC.

  FIG. 2 is a top view of the reflector 142. As shown in FIG. 2, the reflector 142 is provided with slits SL from the inner periphery to the outer periphery. The reflector 142 that reflects heat in the chamber 103 generates a temperature distribution in the radial direction and is subjected to thermal stress. However, by providing the slit SL as shown in FIG. 2, the stress is relieved and the reflector 142 can be prevented from being damaged.

  Further, by forming one slit SL to be formed, the reflector 142 is continuous without being separated from one end surface to the other end surface via the slit SL, and a plurality of one annular reflector 142 is provided. Not divided into parts. Therefore, it is possible to prevent an increase in the number of parts and an increase in reflector support locations.

  When the temperature of the reflector 142 rises, the amount of deformation at the location where the slit SL is formed is greater than at other locations. Therefore, it is preferable that the position of the slit SL and the support position of the reflector 142 are shifted to suppress the influence on the installation posture (tilt or the like) of the reflector 142. For example, when three support members that support the reflector 142 are provided at intervals of 120 °, the slit SL is positioned between the two support members.

  When the film forming apparatus 100 is provided with a thermocouple for measuring the temperature of the film forming region 103b, and the reflector 142 is provided with a hole for passing this thermocouple, such a hole is likely to be subjected to thermal stress. It is preferable to form the slit SL in accordance with this hole.

  In order to reduce the leakage of radiation from the heat source through the slit SL, the width of the slit SL is preferably 0.5 to 1.0 mm.

  Further, when a plurality of reflectors 142 are stacked as in the reflector unit RU1 shown in FIG. 1, it is preferable to shift the position of the slit SL of the upper reflector 142 from the position of the slit SL of the lower reflector 142. Thereby, the leakage of the radiation from the heat source through the slit SL can be suppressed, and the thermal efficiency can be increased.

  The reflector unit RU1 may be composed of a single reflector 142, or a plurality of reflectors 142 may be stacked.

  FIG. 3 is a top view of the reflector unit RU2. As shown in FIG. 3, the reflector unit RU <b> 2 includes annular reflectors 151 to 153. The reflector 152 is provided on the outer periphery of the reflector 151, and the reflector 153 is provided on the outer periphery of the reflector 152.

  For example, the reflector 152 is installed on the outer periphery of the reflector 151 by overlapping the outer periphery of the reflector 151 and the inner periphery of the reflector 152. Similarly, the reflector 153 is installed on the outer periphery of the reflector 152 by overlapping the outer periphery of the reflector 152 and the inner periphery of the reflector 153. In FIG. 3, the reflectors 151 to 153 are illustrated separately for the convenience of explanation.

  The reflector 151 is provided with a slit SL1 from the inner peripheral portion to the outer peripheral portion, and the reflector 151 is continuous without being separated from one end face to the other end face via the slit SL1.

  The reflector 152 is provided with a slit SL2 from the inner periphery to the outer periphery, and the reflector 152 is continuous from one end surface to the other end surface through the slit SL2.

  The reflector 153 is provided with a slit SL3 from the inner periphery to the outer periphery, and the reflector 153 is continuous without being separated from one end surface to the other end surface via the slit SL3.

  In the reflector unit RU2, the temperature of the inner periphery is high and the temperature of the outer periphery tends to be low. Therefore, when the reflector unit RU2 is composed of a single reflector, the temperature difference between the inner peripheral portion and the outer peripheral portion increases, and the reflector is easily damaged by thermal stress. In the present embodiment, the reflector unit RU2 is divided into a plurality of reflectors 151 to 153 in the radial direction and the slits SL1 to SL3 are provided in the reflectors 151 to 153, so that the thermal stress is alleviated and the reflectors 151 to 153 Breakage can be prevented.

  When the temperature of the reflectors 151 to 153 rises, the amount of deformation at the locations where the slits SL1 to SL3 are formed is greater than at other locations. Therefore, it is preferable to install the reflectors 151 to 153 by shifting the positions of the slits SL1 to SL3. For example, as shown in FIG. 3, it is preferable to install the reflectors 151 to 153 so that the positions of the slits SL1 to SL3 are shifted from each other by 120 °.

  FIG. 3 shows an example in which the reflector unit RU2 includes three reflectors 151 to 153, but the number of reflectors may be two or four or more. Further, the reflector unit RU2 may be configured by stacking a plurality of sets of reflectors 151 to 153 vertically.

  As shown in FIG. 1, a gas supply unit 160 is provided on the upper portion of the chamber 103 of the film forming apparatus 100. The gas supply unit 160 supplies purge gas and process gas to the film formation region 103b via gas flow paths (gas pipes) 161-163. For example, argon gas or hydrogen gas as a purge gas is supplied to the film formation region 103b through the gas flow path 161. Further, silane gas or propane gas is supplied as a process gas to the film formation region 103b via the gas flow paths 162 and 163. In FIG. 1, one gas flow path is provided for each gas, but a plurality of gas flow paths may be provided.

  Each gas is supplied to the chamber 103 from a position higher than the reflector unit RU1, and the gas flow paths 161 to 163 are provided so as to penetrate the reflector 141 of the reflector unit RU1. That is, the gas inlet into the chamber 103 is at a higher position than the reflector unit RU1, and gas is supplied to the film formation region below the reflector unit RU1 via the gas flow paths 161-163.

  Since the radiation from the heat source is reflected by the reflector units RU 1 and RU 2, the temperature of the film formation region 103 b can be efficiently raised during film formation on the substrate 101. In addition, since the reflectors 142 and 151 to 153 constituting the reflector units RU1 and RU2 are provided with slits SL and SL1 to SL3, the reflectors 142 and 151 to 153 are heated even when the film formation region 103b becomes high temperature. Breakage due to stress can be prevented.

  The gas supply port to the chamber 103 is separated from the film formation region 103b by the reflector unit RU1. Therefore, even when the film formation region 103b is heated to about 1500 to 1700 ° C., the temperature of the region above the reflector unit RU1 in the chamber 103 is equal to or lower than the reaction temperature of silane (about 600 ° C.) and the silane is liquefied. Can be maintained at a temperature that does not. Accordingly, silane can be supplied to the film formation region without being reacted, and a desired film can be formed on the substrate 101.

  In the above embodiment, a radiation thermometer may be provided on the upper portion of the chamber 103 so that the temperature of the substrate 101 can be measured. In this case, a quartz glass window is provided in a part of the chamber 103, and the temperature of the substrate 101 is measured with a radiation thermometer through the quartz glass window.

  The present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 100 Film-forming apparatus 101 Substrate 103 Chamber 103a Side wall (inner wall)
RU1, RU2 Reflector unit 160 Gas supply part

Claims (5)

A film forming chamber for forming a film on a substrate;
A heater for heating the substrate from below;
A first reflector unit provided in an upper part of the film forming chamber;
A gas supply unit for supplying a process gas to the film formation chamber;
With
The first reflector unit includes an annular first reflector, and the first reflector is provided with a first slit from an inner peripheral portion to an outer peripheral portion, and the first reflector is provided via the first slit. A film forming apparatus characterized in that the film is continuous without being separated from one end face to the other end face. The first reflector unit further includes an annular second reflector,
The second reflector is provided with a second slit from the inner periphery to the outer periphery, and the second reflector is continuous without being separated from one end surface to the other end surface via the second slit,
2. The film forming apparatus according to claim 1, wherein the second reflector is stacked on the first reflector by shifting the position of the second slit from the position of the first slit. A second reflector unit provided at a lower portion of the first reflector unit;
The second reflector unit has an annular third reflector and fourth reflector,
The third reflector is provided with a third slit from the inner periphery to the outer periphery, and the third reflector is continuous without being separated from one end surface to the other end surface via the third slit,
The fourth reflector is provided with a fourth slit from the inner periphery to the outer periphery, and the fourth reflector is continuous without being separated from one end surface to the other end surface via the fourth slit,
3. The component according to claim 1, wherein the third reflector is provided on an inner peripheral side of the fourth reflector by shifting the position of the third slit from the position of the fourth slit. Membrane device. A SiC substrate is carried into a film forming chamber provided with a reflector unit at the top,
A process gas containing silane gas is taken in from a position above the reflector unit, and the process gas is supplied to a lower region of the reflector via a gas flow path penetrating the reflector unit to form a composition on the SiC substrate. A film forming method for forming a film,
The reflector unit includes an annular reflector, and the reflector is provided with a slit from an inner periphery to an outer periphery, and the reflector is continuous without being separated from one end surface to the other end surface via the slit. And
During film formation on the SiC substrate, a lower region of the reflector unit in the film formation chamber is set to a first predetermined temperature, and an upper region of the reflector unit is set to a second predetermined temperature lower than the first predetermined temperature. A film forming method characterized by the above. A reflector unit that is provided in an upper part of a film forming chamber for forming a film on a substrate and reflects heat from a heater in the film forming chamber;
A first reflector having an annular shape, provided with a first slit from an inner periphery to an outer periphery, and continuous from one end surface to the other end surface via the first slit;
A second reflector having an annular shape, provided with a second slit from the inner periphery to the outer periphery, and continuous from one end surface to the other end surface via the second slit;
With
The reflector unit is characterized in that the second reflector is stacked on the first reflector by shifting the position of the second slit from the position of the first slit.

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