JP7342719B2 - Film forming equipment - Google Patents

Description

The present invention relates to a film forming apparatus, for example, depositing polycrystalline silicon carbide (hereinafter sometimes referred to as "SiC") on a support substrate by chemical vapor deposition (hereinafter sometimes referred to as "CVD method"). The present invention relates to a film forming apparatus capable of forming a film.

SiC is a compound semiconductor material composed of silicon (hereinafter sometimes referred to as "Si") and carbon. SiC not only has an excellent dielectric breakdown field strength 10 times that of Si and a band gap three times that of Si, but also allows for the control of p-type and n-type over a wide range, which is necessary for device fabrication. For these reasons, it is expected to be a material for power devices that exceeds the limits of Si.

However, compared to the widely popular Si semiconductor, SiC semiconductors cannot be produced in large quantities and are expensive because large-area SiC single crystal substrates cannot be obtained and the process is complicated. Ta.

Various efforts have been made to reduce the cost of SiC semiconductors. For example, Patent Document 1 discloses a method for manufacturing a SiC substrate, in which at least an SiC single crystal substrate and a SiC polycrystalline substrate having a density of micropipes of 30 pieces/cm ² or less are prepared, and the single crystal substrate and the It is described that a step of bonding a polycrystalline silicon carbide substrate is performed, and then a step of thinning the single crystal substrate is performed to manufacture a substrate in which a single crystal layer is formed on the polycrystalline substrate.

Furthermore, Patent Document 1 discloses that before the step of bonding a SiC single crystal substrate and a SiC polycrystalline substrate, a step of implanting hydrogen ions into the SiC single crystal substrate to form a hydrogen ion implantation layer is performed, After the process of bonding the crystal substrate and the SiC polycrystalline substrate, and before the process of thinning the SiC single crystal substrate, heat treatment is performed at a temperature of 350°C or less, and the process of thinning the SiC single crystal substrate is performed using hydrogen. A method for manufacturing a SiC substrate is described, which includes a step of mechanically peeling off an ion-implanted layer.

With this method, more SiC substrates can be obtained from one SiC single crystal ingot.

JP2009-117533A Patent No. 3857446

However, most of the SiC bonded substrates manufactured by the method described in Patent Document 1 are SiC polycrystalline substrates. Therefore, it is necessary to use a SiC polycrystalline substrate with a sufficient thickness to have mechanical strength so that the SiC bonded substrate is not damaged during handling such as polishing.

Conventionally, the SiC polycrystalline substrate has been produced by forming SiC polycrystalline films on a large number of graphite support substrates by CVD, and then depositing each support substrate coated with the SiC polycrystalline film on the end face of the SiC polycrystalline film. The support substrate is exposed from the side surface of the SiC polycrystalline film by grinding or the like, and then the supporting substrate is separated from the SiC polycrystalline film by baking in an oxidizing atmosphere, etc., and then the SiC polycrystalline film is ground by surface grinding and, if necessary, A SiC polycrystalline substrate with a desired thickness and surface condition was obtained by polishing the substrate (for example, Patent Document 2).

However, in the above-described method, when a large number of support substrates are placed into a deposition chamber of a CVD deposition apparatus and a film is formed, the film formation may be affected by the temperature distribution in the deposition chamber or the concentration gradient of the deposition gas. There is a risk that large variations in the film thickness of the SiC polycrystalline film may occur, and this variation may cause the film formation process to take a longer time and the amount of grinding during surface grinding of the SiC polycrystalline film after film formation to increase. This has been a factor that reduces the productivity of polycrystalline films and increases manufacturing costs.

The present invention has been made with attention to such problems, and it is an object of the present invention to provide a film forming apparatus that can suppress variations in film thickness within the same plane of a film forming target surface of a film forming target substrate. purpose.

As a result of intensive research to solve the above problems, the present inventors have discovered that in a method of forming SiC polycrystalline films on, for example, a large number of support substrates by CVD, raw material gas is flowed, for example, in the vertical direction, and the supporting substrates are The support substrate is arranged so that the surface normal of the surface to be film-formed on the substrate is perpendicular to the flow direction of the raw material gas, and the surface normal to the surface to be film-formed on the support substrate and the rotation axis around which the support substrate rotates. We discovered that by using a film forming apparatus that can form a film by rotating the support substrate in a direction in which the Ta.

That is, in order to solve the above problems, the film forming apparatus of the present invention includes a film forming chamber for forming a film on a substrate to be formed by chemical vapor deposition, and a source gas introduction chamber for introducing a source gas into the film forming chamber. a raw material gas outlet for discharging the raw material gas from the film forming chamber; arranged so as to be perpendicular to the flow direction, rotate in the flow direction of the raw material gas, so that the film formation target substrate can be rotated in the flow direction of the raw material gas, and the film formation target surface of the film formation target substrate is rotated in the flow direction of the raw material gas. The apparatus includes a rotating shaft held parallel to the flow direction of the raw material gas, and a rotational drive means for rotating the rotating shaft.

The rotating shaft may include a fixing part that skewers and fixes the substrate to be film-formed.

The rotation shaft may include a grip portion that grips an end portion of the substrate to be film-formed.

According to the present invention, it is an object of the present invention to provide a film forming apparatus that can suppress variations in film thickness within the same plane of a film forming target surface of a film forming target substrate. Therefore, the present invention has the effect of improving productivity and reducing manufacturing costs by shortening film formation time, reducing the amount of grinding in surface grinding, etc.

FIG. 2 is a schematic diagram showing an example of a mode in which a wafer-shaped substrate 100 to be film-formed is held by a rotating shaft 200 during film-forming. FIG. 2 is a schematic diagram showing an example of a mode in which a plurality of wafer-shaped film-forming target substrates 100 are held on a rotating shaft 200 during film-forming. 3 is a schematic diagram showing an example of a mode in which a plurality of wafer-shaped film-forming target substrates 100 are held on a rotating shaft 200 during film formation, which is different from FIG. 2. FIG. 4 is a schematic diagram showing an example of a mode in which a plurality of wafer-shaped film-forming target substrates 100 are held on a rotating shaft 200 during film formation, which is different from FIG. 3. FIG. FIG. 1 is a schematic cross-sectional view of a film forming apparatus 1000. FIG. 1 is a schematic cross-sectional view of a film forming apparatus 1001. 10 is a schematic cross-sectional view of a film forming apparatus 1002. FIG. 5 is a schematic diagram showing the configuration of gears in a gearbox 530. FIG. FIG. 2 is a schematic cross-sectional view of a film forming apparatus 1003. 9 is a schematic diagram showing a configuration of gears in a gearbox 530 in a different manner from FIG. 8. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to these embodiments.

[Film forming equipment]
The film forming apparatus is an apparatus capable of forming a thin film of a predetermined substance on a surface of a substrate to be film-formed using a chemical vapor deposition method. For example, by using a support substrate made of carbon or a support substrate made of silicon as a film-forming target substrate, any silicon carbide polycrystalline film or silicon carbide single crystal film can be formed on these support substrates.

Such a film forming apparatus includes a film forming chamber, a raw material gas inlet, a raw material gas outlet, a rotating shaft, and a rotational drive means as described below.

<Film formation chamber>
In the film forming chamber, a substrate to be film-formed is installed in the room, and a thin film is formed on the substrate to be film-formed by chemical vapor deposition. The internal shape of the film forming chamber can be any shape, such as a rectangular parallelepiped shape or a cylindrical shape.

Further, it is preferable that the film forming chamber is made of graphite. Graphite can be easily processed into a rectangular parallelepiped or cylindrical shape, and by forming the film under an inert atmosphere, it can have sufficient durability under high-temperature film formation conditions.

The film forming chamber includes a source gas inlet and a source gas outlet, which will be described later. Although there are no particular restrictions on the location of these ports, for example, if the source gas inlet is located on the floor of the film forming chamber and the source gas outlet is located on the ceiling of the film forming chamber, the source gas will be removed during the film forming process. flows vertically from bottom to top.

<Raw material gas inlet>
The raw material gas inlet introduces raw material gas into the film forming chamber. For example, when forming a film on a support substrate made of carbon or a support substrate made of silicon, Si-based gas and C-based gas may be introduced into the film formation chamber using separate raw material gas inlets, and these gases may be introduced in advance into the film formation chamber. The mixed gas may be introduced into the film forming chamber. Moreover, the source gas is entrained by a carrier gas, and may be further entrained by a dopant gas.

As the raw material gas introduction tube having a raw material gas inlet at the end, for example, when forming a film on a carbon support substrate or a silicon support substrate, any tube such as a graphite tube or a stainless steel tube can be used. Can be used.

In addition, in order to control the temperature of the raw material gas inlet so that the raw material does not precipitate and block the raw material gas inlet, temperature control means such as a heater that can appropriately heat the raw material gas inlet pipe and a cooler that can cool it are provided. It's okay.

<Raw material gas outlet>
The raw material gas exhaust port discharges the raw material gas from the film forming chamber. As the raw material gas discharge pipe having a raw material gas discharge port at its end, any pipe such as a graphite pipe or a stainless steel pipe can be used.

In addition, in order to control the temperature of the raw material gas outlet so that the raw material does not precipitate and block the raw material gas outlet, temperature control means such as a heater that can appropriately heat the raw material gas exhaust pipe and a cooler that can cool the raw material gas exhaust pipe are installed. It's okay.

<Axis of rotation>
The rotating shaft rotates in the direction in which the raw material gas flows, so that the substrate to be film-formed can be rotated in the direction in which the raw material gas flows, and the surface to be film-formed of the substrate to be film-formed is held parallel to the direction in which the raw material gas flows. . During the film forming process, the source gas flows from the source gas inlet to the source gas outlet within the film forming chamber. Therefore, the rotating shaft is arranged in the film forming chamber between the source gas inlet and the source gas outlet so that its longitudinal direction is orthogonal to the flow direction of the source gas. By arranging the rotation shaft in this way, it becomes possible to rotate in the direction in which the raw material gas flows, and furthermore, it is possible to rotate the substrate to be film-formed in the direction in which the raw material gas flows, and also to rotate the film-forming target surface of the film-forming target substrate in the direction in which the raw material gas flows. can be held parallel to the flow direction of the raw material gas.

(Fixed part)
The rotating shaft can include a fixing part that skewers and fixes the substrate to be film-formed. For example, the entire length of the rotating shaft body is threaded, and by passing this rotating shaft body through an opening in the center of the substrate to be film-formed, the substrate to be film-formed can be skewered. By fastening the fixing members such as nuts and washers from both sides of the substrate to be film-formed, the substrate to be film-formed can be fixed.

For example, when forming a support substrate made of carbon or a support substrate made of silicon, the rotating shaft body and the fixing member are preferably made of graphite. If it is made of graphite, it can be easily threaded and processed into nuts and washers.Also, by forming the film under an inert atmosphere, it has sufficient durability to withstand high-temperature film forming conditions. You can have it.

FIG. 1 is a schematic diagram showing an example of a mode in which a wafer-shaped substrate 100 to be film-formed is held on a rotating shaft 200 during film formation, as an example of a mode in which the substrate to be film-formed is fixed by the fixing section.

The substrate 100 to be film-formed has an opening 110 in its center through which the rotating shaft 200 can be inserted. It is fastened and fixed to the rotating shaft 200 using two nuts 210 as fixing members from the front surface 120a and the back surface 120b. It is held on a rotating shaft 200. The rotating shaft 200 and the nut 210 can be made of materials that can withstand film formation by chemical vapor deposition, and for example, the rotating shaft 200 and the nut 210 can be made of carbon. By rotating the rotating shaft 200 counterclockwise as shown by arrow A, for example, the film-forming target substrate 100 can be rotated counterclockwise as shown by arrow A. Further, the rotating shaft 200 may be rotated clockwise.

Note that the rotation speed of the substrate to be film-formed during the film-forming process is not particularly limited, but can be set to, for example, 0.1 to 60 rpm. If the rotation speed is slower than 0.1, the thickness of the deposited film may be significantly uneven. If the rotation speed is faster than 60 rpm, there is a risk of damage to the rotating shaft 200 or the generation of airflow due to the rotation, which may cause the film to become uneven. There is a risk of membrane failure. Further, the front surface 120a and the back surface 120b of the substrate 100 to be film-formed are the surface 120 to be film-formed, and a vector perpendicular to the surface 120 to be film-formed is the surface normal 300.

Further, arrow B indicates the direction in which the raw material gas flows. The source gas is not particularly limited as long as it can form a film, and commonly used source gases can be used. For example, when forming a polycrystalline film of silicon carbide, a Si-based source gas and a C-based source gas are used. As the Si-based raw material gas, for example, silane (SiH ₄ ) can be used, as well as chlorine-based Si raw material-containing gases containing Cl that have an etching effect, such as SiH ₃ Cl, SiH ₂ Cl ₂ , SiHCl ₃ , and SiCl ₄ . (chloride-based raw materials) can also be used. As the C-based raw material gas, for example, methane (CH ₄ ), propane (C ₃ H ₈ ), and acetylene (C ₂ H ₂ ) can be used.

When forming a polycrystalline film of titanium nitride, TiCl ₄ gas, N ₂ gas, or the like can be used. When forming a polycrystalline film of aluminum nitride, AlCl ₃ gas, NH ₃ gas, or the like can be used. When forming a polycrystalline film of titanium carbide, TiCl ₄ gas, CH ₄ gas, or the like can be used. When forming a polycrystalline film of diamond-like carbon, a hydrocarbon gas such as acetylene can be used.

Further, the raw material gas may be accompanied by a carrier gas. A commonly used carrier gas can be used as long as the raw material gas can be spread onto the film formation target substrate 100 without inhibiting film formation. For example, when forming a silicon carbide polycrystalline film, hydrogen (H ₂ ), which has excellent thermal conductivity and has an etching effect on SiC, can be used.

Further, an impurity doping gas can be supplied as a third gas simultaneously with these source gas and carrier gas. For example, nitrogen (N ₂ ) can be used when the conductivity type is n-type, and trimethylaluminum (TMA) can be used when the conductivity type is p-type.

When forming a film using the film forming apparatus of the present invention, the surface normal 300 of the film-forming surface 120 of the film-forming target substrate 100 is perpendicular to the flow direction B of the raw material gas, and the surface normal 300 and the film-forming surface 120 are perpendicular to each other. Film formation is performed by rotating the film formation target substrate 100 in a direction in which the rotation axis 200 on which the film formation target substrate 100 rotates is parallel. In this way, by supplying the raw material gas along the film-forming target surface 120 while rotating the film-forming target substrate 100 and forming the film, the raw material gas is supplied unevenly to the film-forming target surface 120. Therefore, it is possible to suppress variations in film thickness within the same plane of the film-forming target surface 120 of the film-forming target substrate 100.

Note that the direction in which the source gas flows can be arbitrarily set to be parallel to the film-forming target surface 120; for example, it may be vertical as shown by arrow B in FIG. 1, or it may be horizontal. It's okay.

Further, FIG. 2 is a schematic diagram showing an example of a mode in which a plurality of wafer-shaped film-forming target substrates 100 are held on a rotating shaft 200 during film-forming. When forming a film using the film forming apparatus of the present invention, a method of forming a film on a plurality of film forming target substrates 100 as shown in FIG. 2 may be used. By installing the number of substrates 100 to be film-formed that can be film-formed in a single process in the film-forming chamber of the film-forming apparatus, film-forming efficiency can be increased. Here, it is preferable to form a film by installing the plurality of film-forming target substrates 100 so that their central axes 130 are aligned with the rotation axis 200. That is, each substrate 100 to be film-formed has an opening 110 in its center through which the rotating shaft 200 can be inserted. 100, and is fastened and fixed to the rotating shaft 200 using a plurality of nuts 210. With such an arrangement, the central axis 130 of the plurality of film-forming target substrates 100 can be made to coincide with the rotation axis of the rotating shaft 200, and the film-forming conditions can be adjusted for any of the film-forming target substrates 100. This makes it possible to prevent the source gas from being unbalancedly supplied to any of the film-forming surfaces 120, so that in any film-forming target substrate 100, the same surface of the film-forming surface 120 can be It is possible to suppress variations in film thickness within the film.

When a plurality of substrates 100 to be film-formed are formed into films in one process as shown in FIG. 2, it is preferable that the inter-substrate distances 140 of the plurality of substrates 100 to be film-formed are equally spaced. By having the inter-substrate distances 140 at equal intervals, the source gas can be uniformly supplied to any of the film-forming surfaces 120, so that the Variations in film thickness can be further suppressed.

(gripping part)
The rotating shaft can include a gripping part that grips an end of the substrate to be film-formed. For example, like the fixing part above, the entire length of the rotating shaft body is threaded, and a gripping member consisting of a nut or washer is used to attach the end of the rotating shaft from both sides of the substrate to be film-formed. By sandwiching and then tightening the gripping members, it is possible to grip the edge of the substrate to be film-formed. Furthermore, instead of a nut or washer, a spacer having an opening through which the rotating shaft body passes can be used as the gripping member, and the edge of the substrate to be film-formed can be gripped by sandwiching it from both sides with the spacer. can.

For example, when forming a support substrate made of carbon or a support substrate made of silicon, the rotating shaft body and the gripping member are preferably made of graphite. If it is made of graphite, it can be easily threaded and processed into nuts and washers.Also, by forming the film under an inert atmosphere, it has sufficient durability to withstand high-temperature film forming conditions. You can have it.

FIG. 3 shows a mode in which a plurality of wafer-shaped target substrates 100 are held on a rotating shaft 200 during film formation, which is a different mode from FIG. A schematic diagram showing an example is shown. When forming a film using the manufacturing apparatus of the present invention, as shown in FIG. By installing the film forming apparatus 100 in the film forming chamber of the film forming apparatus, the film forming efficiency can be increased. Further, in the case of the embodiment shown in FIG. 3, a plurality of film-forming target substrates 100 constitute a rotationally symmetrical substrate group 400 arranged rotationally symmetrically around the rotation axis 200. Each film-forming target substrate 100 is gripped and fixed to a rotating shaft 200 by a pair of nuts 210 as fixing means. Although the fixing means is not particularly limited, for example, in addition to the threaded nut 210, the substrate 100 to be film-formed can be fixed by sandwiching and gripping the substrate 100 to be film-formed using washers or the like.

The rotationally symmetrical substrate group 400 is composed of a plurality of film formation target substrates 100 on the same plane, and although four film formation target substrates 100 are shown in FIG. A rotationally symmetrical substrate group 400 can be configured by an arbitrary number of about eight substrates 100 to be film-formed, and the rotationally symmetrical substrate group 400 can be gripped and fixed to the rotating shaft 200 by a pair of nuts 210. By forming a rotationally symmetrical substrate group 400 with a plurality of film-forming target substrates 100 and rotating this, film-forming conditions can be made uniform for all film-forming target substrates 100. Therefore, by being able to suppress supply of the raw material gas unevenly to any of the deposition target surfaces 120, the film thickness within the same deposition target surface 120 can be reduced in any of the deposition target substrates 100. Variation can be suppressed.

Further, FIG. 4 is a schematic diagram showing an example of a mode in which a plurality of wafer-shaped film-forming target substrates 100 are held on the rotation shaft 200 during film formation, which is different from FIG. 3. Here, it is preferable that the rotational axes 410 of the plurality of rotationally symmetrical substrate groups 400 all coincide with each other. That is, the film-forming target substrates 100 of any rotationally symmetrical substrate group 400 are arranged to be fixed to the same rotation axis 200. With such an arrangement, any of the rotation axes 410 of the plurality of rotationally symmetrical substrate groups 400 can be made to coincide with the rotation axis of the rotation axis 200, and the film formation conditions can be adjusted for any of the film formation target substrates 100. This makes it possible to prevent the source gas from being unbalancedly supplied to any of the film-forming surfaces 120, so that in any film-forming target substrate 100, the same surface of the film-forming surface 120 can be It is possible to suppress variations in film thickness within the film.

As shown in FIG. 4, when forming a film on the film formation target substrates 100 of a plurality of rotationally symmetrical substrate groups 400 in a single process, the inter-substrate distances 420 between the plurality of rotationally symmetrical substrate groups 400 are equally spaced. It is preferable that Since the distances 420 between the substrates are equal, the raw material gas can be evenly supplied to any film formation target surface 120 without any bias, so that the Variations in film thickness can be further suppressed. The inter-substrate distance 420 can be made equal, for example, by adjusting the width of the nut 210 or by using a spacer or the like in addition to the nut 210.

<Rotation drive means>
The rotation drive means rotates the rotation shaft. The rotational drive means can include, for example, an engine equipped with a piston as a prime mover, and a connecting rod or crankshaft that replaces the piston movement by the piston with rotational movement, and the crankshaft connects to the rotational shaft to rotate the rotational shaft. can do.

In addition, when a motor is used as the prime mover, the rotational drive means includes the motor, a motor belt that transmits the rotation of the motor shaft due to the operation of the motor to the rotating shaft, a first pulley that connects the shaft and the motor belt, and the motor. A second pulley connecting the belt and the rotating shaft can be provided. The rotating shaft can be rotated by transmitting the rotational motion of the motor to the shaft, the first pulley, the motor belt, and the second pulley in this order. Further, the shaft of the motor can be extended to form the rotating shaft 200.

For example, when depositing a support substrate made of carbon or a support substrate made of silicon, the connecting rod, crankshaft, first pulley, and second pulley of the rotational drive means, if provided in the deposition chamber, must be made of graphite. is preferred. If it is made of graphite, it is easy to process, and by forming the film under an inert atmosphere, it can have sufficient durability under high-temperature film formation conditions. A graphite chain can be used in place of the motor belt.

Note that if the rotational drive means is provided outside the casing of the film forming chamber, it does not need to be made of a material that can handle the film forming environment, and may be made of metal, FRP, etc. Any rotational driving means that can be generally used may be used.

(Other configurations)
The film forming apparatus may have a configuration other than the above. For example, it may include a heater that controls the temperature inside the film forming chamber, a water-cooled stainless steel casing that is located outside the heater, and serves as the exterior of the film forming apparatus.

(Film forming apparatus 1000)
An example of the film forming apparatus of the present invention will be described below with reference to the drawings.

FIG. 5 shows a schematic cross-sectional view of the film forming apparatus 1000. The film forming apparatus 1000 includes a film forming chamber 1010 for forming a film on a film forming target substrate 100 held on a rotating shaft 200 using a plurality of nuts 210, and an inlet 1020 for introducing source gas and carrier gas into the film forming chamber 1010. , an exhaust port 1030 that exhausts the raw material gas and carrier gas discharged from the film forming chamber 1010 to the outside of the film forming apparatus 1000, and an exhaust gas that introduces the raw material gas and carrier gas discharged from the film forming chamber 1010 to the exhaust port 1030. A box 1050 that covers the introduction chamber 1040 and the exhaust gas introduction chamber, a heater 1060 that controls the temperature inside the film forming chamber 1010 from outside the box 1050, and a water-cooled stainless steel that is located outside the heater 1060 and serves as the exterior of the film forming apparatus 1000. The casing 1100 made of

Further, in the film forming apparatus 1000, the shaft of a motor 500 that is grounded on the outer wall of the casing 1100 as a rotational driving means serves as a rotating shaft 200, and a horizontal hole is formed from the casing 1100 through the film forming chamber 1010 to the box 1050. and pass the rotating shaft 200 there. Then, the rotating shaft 200 is rotated by driving the motor. Note that the rotation speed of the rotating shaft 200 can be controlled by a switch or the like that can control the rotation speed, and the rotation can also be controlled by mechanical or electrical control means such as a brake. Further, the end of the rotating shaft 200 opposite to the motor 500 can be fixed to the box 1050 by a bearing 510 that is grounded on the outer wall of the box 1050 so as not to inhibit the rotation of the rotating shaft 200.

(Film forming apparatus 1001)
FIG. 6 shows a schematic cross-sectional view of a film forming apparatus 1001 as an example of a film forming apparatus of the present invention that is different from the film forming apparatus 1000. The film forming apparatus 1001 is similar to the film forming apparatus 1000 in that a rotating shaft 200 is fixed to a box 1050 by a bearing 510, but instead of the motor 500, an engine 600 is used, and a shaft that is moved by a piston by the engine 600 is used. The film forming apparatus 610 is different from the film forming apparatus 1000 in that it is provided with a crankshaft that is located inside a box 620 that is grounded on the outer wall of the casing 1100 and serves as an axis for converting piston motion into rotational force.

The rotating shaft 200 can also be rotated by a rotational drive means including such an engine 600, a shaft 610, and a crankshaft.

(Film forming apparatus 1002)
FIG. 7 shows a schematic cross-sectional view of a film forming apparatus 1002 as an example of the film forming apparatus of the present invention, which is different from the film forming apparatuses 1000 and 1001. The film forming apparatus 1002 is similar to the film forming apparatus 1000 in that it uses a motor 500 and that the rotating shaft 200 is fixed to the box 1050 by a bearing 510, but the shaft 520 of the motor 500 is connected to the rotating shaft 200. This differs from the film forming apparatuses 1000 and 1001 in that a gearbox 530 that changes the rotation direction is grounded on the outer wall of the casing 1100 instead.

FIG. 8 shows a schematic diagram showing the configuration of gears in the gearbox 530. Inside the gearbox 530, a plurality of gears 521 provided near the end of the shaft 520 and a plurality of gears 201 provided near the end of the rotating shaft 200 are provided so as to mesh with each other. Horizontal rotation can be converted into vertical rotation of the rotating shaft 200.

The rotary shaft 200 can also be rotated by a rotary drive means including the motor 500, the shaft 520, and the gears 201 and 521 in the gear box 530.

(Film forming apparatus 1003)
FIG. 9 shows a schematic cross-sectional view of a film forming apparatus 1003 as an example of a film forming apparatus of the present invention that is different from the film forming apparatuses 1000, 1001, and 1002. The film forming apparatus 1003 is the same as the film forming apparatus 1002 in that the rotating shaft 200 is rotated using a motor 500, a shaft 520, and a gear box 530 that changes the direction of rotation. However, the motor 500 is grounded at the upper center of the outer wall of the housing 1100, and the shaft 520 extends from the motor 500 through the housing 1100, the box 1050, the exhaust gas introduction chamber 1040, and into the deposition chamber 1010; There is a gearbox 530 inside the film forming chamber 1010, a rotating shaft 200 extends left and right from the gear box 530, and holds the substrate 100 to be film-formed on the left and right sides of the gear box 530, and bearings 510 are provided at both ends of the rotating shaft. It differs from the film forming apparatus 1002 in that it is fixed to a box 1050 by a.

FIG. 10 is a schematic diagram showing the configuration of gears in the gearbox 530 in a different manner from FIG. 8. Inside the gearbox 530, a plurality of gears 521 are provided near the end of the shaft 520, and a plurality of gears 201 are provided at a portion of the rotating shaft 200 that is equidistant from both longitudinal ends of the rotating shaft 200 or near that portion. are provided to mesh with each other, and horizontal rotation by the shaft 520 can be converted into vertical rotation of the rotating shaft 200.

[Example of substrate manufacturing method]
Next, an example of a method for manufacturing a substrate using the film forming apparatus of the present invention will be described. The substrate manufacturing method includes a film forming method using the above-described film forming apparatus of the present invention. For example, in a film forming chamber 1010 of a film forming apparatus 1000 shown in FIG. 5, a plurality of film forming target substrates 100 are fixed to a rotating shaft 200. Then, in order to remove the atmosphere from inside the film forming chamber 1010, the inside of the film forming chamber 1010 is evacuated using a rotary pump or the like, and then the inside of the film forming chamber 1010 is returned to atmospheric pressure using an inert gas such as Ar. The temperature inside the film forming chamber 1010 is raised to the reaction temperature while flowing gas. When the inside of the film forming chamber 1010 reaches the reaction temperature, the inert gas is stopped and the motor 500 is operated to rotate the rotating shaft 200 to form a film with the source gas, carrier gas, etc. while rotating the film forming target substrate 100. It flows into the chamber 1010. Thereby, a film can be formed on the film-forming target substrate 100.

Further, as an example of a method for manufacturing a substrate, a method for manufacturing a polycrystalline silicon carbide substrate is taken as an example. This manufacturing method further includes an exposure step and a combustion removal step, which will be described below.

<Exposure process>
An example of the exposure step is to remove the edges of the silicon carbide polycrystalline film on the surface of the carbon support substrate obtained by the above-described film forming method, and then remove the carbon support substrate. This includes a step of exposing the substrate. This step exposes the carbon support substrate, making it easier to vaporize the carbon support substrate in the combustion removal step described below.

In the film forming process, a silicon carbide polycrystalline film is formed on the side wall of the carbon support substrate, so this is put into an end face processing device, for example, and the silicon carbide polycrystalline film is processed inward from the end face of the formed silicon carbide polycrystalline film. By grinding 4 mm, the end face of the carbon support substrate can be exposed. Note that if the outer periphery of the carbon support substrate is masked with ring-shaped graphite or the like before forming the silicon carbide polycrystalline film, end face processing is not required, and in this case, the mask can be removed. This is the exposure process.

Alternatively, the carbon support substrate with a silicon carbide polycrystalline film formed on its surface may be hollowed out with a core drill or the like to a desired diameter (for example, 6 inches diameter), thereby exposing the carbon support substrate at the outer periphery of the side surface. can.

<Combustion removal process>
An example of the combustion removal step is a step of holding the carbon support substrate after the exposure step under conditions of 1 atm pressure and 800° C. in the atmosphere for 100 hours or more. In this step, the carbon supporting substrate can be burned and removed, so a silicon carbide polycrystalline substrate can be obtained.

(polishing process)
The method for manufacturing a silicon carbide polycrystalline substrate may include a polishing step of polishing the surface of the formed silicon carbide polycrystalline film after the combustion removal step. If a silicon carbide polycrystalline substrate is to be used in the manufacture of semiconductors, it must have surface precision that can be used in semiconductor manufacturing processes. Therefore, it is preferable to smooth the surface of the silicon carbide substrate through this step.

For example, the surface of the silicon carbide substrate is smoothed by lapping it with diamond slurry, hard polishing it with a mixed slurry of diamond and alumina, and then polishing it with silica slurry (colloidal silica, pH 11). can do.

(Other processes)
The method for manufacturing a silicon carbide substrate of the present invention can include other steps in addition to the steps described above. For example, a cleaning process for removing deposits on the silicon carbide substrate due to a polishing process, etc. may be mentioned. Further, the method for manufacturing a substrate of the present invention can include any step for manufacturing a substrate when manufacturing a substrate different from a silicon carbide polycrystalline substrate.

EXAMPLES Examples of the present invention will be specifically described below with reference to comparative examples. Here, a carbon support substrate was used as a film-forming target substrate, and a silicon carbide polycrystalline film was formed on the carbon support substrate. Note that the present invention is not limited to these Examples.

(Example 1)
The film forming apparatus 1000 used to form the silicon carbide polycrystalline film was a hot wall type thermal CVD apparatus in which source gas was introduced from the bottom of the film forming chamber 1010 and discharged from the ceiling. As the substrate 100 to be film-formed, a carbon support substrate was used, which had a wafer shape with a thickness of 5 mm and a diameter of 400 mm, and had an opening 110 with a diameter of 50 mm in the center. As in the embodiments shown in FIGS. 2 and 5, the substrate 100 to be film-formed is placed in the film-forming chamber 1010 so that its surface normal 300 is parallel to the rotation axis 200 and perpendicular to the flow direction of the source gas. Placed. There were six film formation target substrates 100 used for film formation, and the film formation target substrates 100 were skewered on the rotating shaft 200 so that the inter-substrate distance 140 of the opposite film formation target surfaces 120 of each film formation target substrate 100 was 20 mm. Fixed. Note that the distance between the inner wall of the film forming chamber 1010 and the film forming surface 120 facing the inner wall is also 20 mm so that the flow of the source gas passing between the film forming target substrates 100 is uniform. installed.

After the inside of the film forming chamber 1010 is evacuated with an exhaust pump to make it into a reduced pressure state, Ar gas is introduced to return the pressure inside the film forming chamber 1010 to atmospheric pressure, and while the Ar gas is flowing, the film forming chamber 1010 is The inside was heated to 1400°C. SiCl ₄ and CH ₄ were used as source gases, and H ₂ was used as a carrier gas. While rotating the substrates 100 to be film-formed at a rotational speed of 1 rpm, the front surface of the surface 120 to be film-formed was prepared under conditions such that the gas flow ratio was SiCl ₄ :CH ₄ :H ₂ =1:1:10. Film formation was performed for 2.5 hours on the surface 120a and the back surface 120b. At this time, the pressure inside the film forming chamber 1010 was controlled to be 20 kPa.

After the film-forming process was completed, four substrates each having a diameter of 150 mm were cut out of the film-forming target substrate 100 on which the silicon carbide polycrystalline film had been deposited using a core drill having an inner diameter of 151 mm. The carbon supporting substrate, which is the film-forming target substrate 100, is exposed at the outer periphery of each hollowed-out substrate. By heating this substrate at 800° C. for 100 hours or more in an air atmosphere, the carbon support substrate was burned and removed, and a total of eight silicon carbide polycrystalline substrates were separated per one film-forming target substrate 100. The remaining five silicon carbide polycrystalline films 100 on which the silicon carbide polycrystalline films were formed were also subjected to the same exposure process and combustion removal process to obtain a total of 48 silicon carbide polycrystalline substrates per batch. Ta.

As a result of measuring the thickness of all of these 48 polycrystalline silicon carbide substrates, the thinnest part in the same plane was 130 μm, and the thickest part was 400 μm.

(Example 2)
As the substrate 100 to be film-formed, a carbon support substrate having a wafer shape with a thickness of 5 mm and a diameter of 151 mm and without an opening 110 was used. As shown in FIG. 4, one set of rotationally symmetrical substrates 400 is a set of rotationally symmetrical substrates 400 that are rotationally symmetrical with respect to the rotational axis 200 and arranged between nuts 210 in a four-fold symmetrical manner. A total of six rotationally symmetrical substrate groups 400 (a total of 24 substrates 100 to be film-formed) were arranged in the film-forming chamber 1010 so that the rotationally symmetrical substrates 420 were equally spaced at 20 mm. In addition, the distance between the inner wall of the film forming chamber 1010 and the film forming surface 120 facing the inner wall is set to 20 mm so that the flow of the source gas passing between the film forming target substrates 100 becomes uniform. installed. The film was formed under the same conditions as in Example 1.

After the film-forming process is completed, the film-forming target substrate 100 on which the silicon carbide polycrystalline film has been deposited is taken out from the film-forming chamber 1010, and a part of the edge of the silicon carbide polycrystalline film is removed to form the film-forming target substrate 100. The carbon support substrate was exposed. Thereafter, the carbon support substrate was burned off by heating this substrate in the air at 800° C. for 100 hours or more. Through these operations, a total of 2 silicon carbide polycrystalline substrates were obtained per 100 film-forming target substrates, and a total of 48 silicon carbide polycrystalline substrates per batch.

As a result of measuring the thickness of all of these 48 polycrystalline silicon carbide substrates, the thinnest part in the same plane was 130 μm, and the thickest part was 400 μm.

(Comparative example 1)
The film formation process, exposure process, and combustion removal process were performed in the same manner as in Example 1, except that the rotation speed of the film formation target substrate 100 in the film formation process was set to 0 rpm (no rotation). As a result of measuring the thickness of all of the 48 silicon carbide polycrystalline substrates obtained, the thinnest part in the same plane was 30 μm, and the thickest part was 520 μm.

[summary]
As described above, according to the present invention, it is possible to suppress variations in the thickness of the deposited film within the same surface of the deposition target surface of the deposition target substrate. In the embodiment, as an example, the case of forming a silicon carbide polycrystalline film on a carbon substrate was introduced, but the effects of the present invention are not limited to this case. It can also be obtained when forming a single crystal film or a polycrystalline film of titanium nitride, aluminum nitride, titanium carbide, diamond-like carbon, or the like.

100 Film formation target substrate 110 Opening 120 Film formation target surface 120a Front surface 120b Back surface 130 Center axis 140 Distance between substrates 200 Rotation axis 201 Gear 210 Nut 300 Surface normal 400 Rotationally symmetrical substrate group 410 Rotation axis 420 Between substrates Distance 500 Motor 510 Bearing 520 Shaft 521 Gear 530 Gearbox 600 Engine 610 Shaft 620 Box 1000 Film forming apparatus 1001 Film forming apparatus 1002 Film forming apparatus 1003 Film forming apparatus 1010 Film forming chamber 1020 Inlet 1030 Exhaust port 1040 Exhaust gas introduction chamber 1050 Box 1060 Heater 1100 Housing A Arrow B Arrow

Claims (1)

a deposition chamber that deposits a film on a substrate to be deposited by chemical vapor deposition;
a source gas inlet for introducing source gas into the film forming chamber;
a raw material gas outlet for discharging raw material gas from the film forming chamber;
In the film forming chamber, the film forming target substrate is arranged between the raw material gas inlet and the raw material gas outlet so that the longitudinal direction thereof is perpendicular to the flowing direction of the raw material gas. a rotating shaft rotatably held with a surface parallel to the flow direction of the raw material gas;
A film forming apparatus comprising: a rotational drive means for rotating the rotational shaft ,
A film forming apparatus, wherein the rotating shaft includes a fixing part that skewers and fixes the substrate to be film formed .

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