JP7234829B2 - Film forming apparatus and film forming method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a film forming apparatus and a film forming method, for example, a film forming apparatus and a film forming apparatus for forming a film of polycrystalline silicon carbide or the like by laminating a plurality of supporting substrates or the like at equal intervals in a non-contact state. It relates to a film forming method.

Silicon carbide (SiC) is a wide bandgap semiconductor with a wide bandgap of 2.2 to 3.3 eV. Research and development of devices (semiconductor elements) made of silicon carbide (SiC), such as electronic devices, short-wavelength optical devices from blue to ultraviolet, and the like, are being actively carried out. In promoting the practical use of SiC devices, it is required to manufacture large-diameter silicon carbide substrates for high-quality SiC epitaxial growth. At present, most of them are manufactured by a sublimation recrystallization method (called an improved Rayleigh method, an improved Rayleigh method, etc.) using a seed crystal, a CVD method (chemical vapor deposition method), or the like.

A method for manufacturing a silicon carbide substrate using a CVD method is to cause a vapor phase reaction of a raw material gas to deposit a silicon carbide product on the substrate surface to form a coating film, and then remove the substrate. can obtain a high-purity silicon carbide substrate. Also, the base material is removed by cutting, polishing, or the like, but if a carbon material is used for the base material, it can be removed by heat treatment in the air.

In Patent Document 1, as a method for manufacturing a silicon carbide substrate by a CVD method, a silicon carbide film is formed on the surface of a base material by a chemical vapor deposition method, and then the base material is removed. Furthermore, a method for manufacturing a silicon carbide substrate by chemical vapor deposition is proposed, which is characterized by forming a silicon carbide film.

When using a thermal CVD method among CVD methods to fabricate a SiC substrate, generally, a silicon carbide substrate is placed on a substrate holder in a growth chamber, and while rotating the holder, the silicon carbide substrate is directly above the SiC substrate. For example, a method of epitaxially growing a SiC single crystal thin film by supplying a raw material gas obtained by mixing a silicon source such as silane gas or chlorosilane gas and a carbon source such as hydrocarbon gas together with a carrier gas such as hydrogen is adopted ( For example, see Non-Patent Document 1).

At this time, a doping gas such as nitrogen (N ₂ ) is usually mixed with the raw material gas and supplied. A substrate processing apparatus in which a SiC substrate is placed on a holder in this way is called a substrate processing apparatus having a horizontal arrangement structure. In addition, even in the substrate processing apparatus with the same horizontal arrangement structure, a plurality of SiC substrates are mounted side by side using a larger holder, and each SiC substrate is rotated (revolved) and the holder is rotated (revolved) so that one time It is also possible to obtain a plurality of epitaxially grown SiC wafers (epitaxial SiC wafers) in the process. A substrate processing apparatus in which a plurality of SiC substrates are arranged on a holder in this way is called a substrate processing apparatus having a planetary structure.

In the case of the substrate processing apparatus of this planetary structure, by combining the rotation and revolution of the SiC substrate, it is possible to create an equivalent epitaxial growth environment for a plurality of SiC substrates. In addition, variations in film thickness and doping density among a plurality of SiC substrates can be suppressed, which is advantageous from the viewpoint of productivity. However, since the number of SiC substrates that can be mounted is determined by the size of the holder, the number of substrates that can be mounted decreases as the diameter of the SiC substrate increases. In particular, in the case of SiC substrates that are intended to have a large diameter, the productivity of epitaxial SiC wafers must also be considered at the same time.

One of the means for improving the productivity of epitaxial SiC wafers is a substrate processing apparatus with a vertically arranged structure in which holders are vertically arranged in a growth chamber and a plurality of SiC substrates are arranged in the stacking direction with gaps between them. be done. According to this, even if the diameter of the SiC substrate is increased, there is not much restriction on the apparatus, and by increasing the number of SiC substrates arranged in the vertical direction, the productivity is higher than that of a substrate processing apparatus with a horizontal arrangement structure. It makes it possible to manufacture epitaxial SiC wafers.

However, in such a substrate processing apparatus with a vertical arrangement structure, control different from that in the case of a substrate processing apparatus with a horizontal arrangement structure is required. For example, if the temperature in the growth chamber is not uniform in the vertical direction, the film thickness of the epitaxially grown film obtained may vary depending on where the SiC substrate is placed, or the doping density may vary. In order to uniformly grow epitaxially grown films on each of the SiC substrates arranged in the vertical direction in the growth chamber, a raw material gas containing a silicon source and a carbon source is introduced through pipes along the vertical direction in the growth chamber. , gas outlets are provided at positions corresponding to the gaps between the SiC substrates, and the raw material gas is supplied to the surfaces of the SiC substrates. Here, if a mixture of a silicon source gas and a carbon source gas is supplied as in the case of a substrate processing apparatus having a horizontal arrangement structure, these gases are mixed in the piping in a high-temperature environment in the thermal CVD method of SiC. reacts to form SiC, which may clog the outlet or deposit SiC in the pipe.

Therefore, a substrate processing apparatus with a vertically arranged structure has been proposed in which a silicon material gas containing a silicon source and a carbon material gas containing a carbon source are respectively introduced into the growth chamber through separate gas introduction pipes (for example, See Patent Documents 2 and 3). By using the substrate processing apparatus with this vertically arranged structure, it is possible to form epitaxially grown SiC films with a uniform film thickness on a large number of SiC substrates. However, even if such a substrate processing apparatus is used, the resulting epitaxial SiC wafer has variations in the doping density of the SiC single crystal thin film depending on the location where the SiC substrate is placed, or a single SiC wafer in a single epitaxial SiC wafer. Doping densities within the same plane of the crystal thin film may vary.

In order to address these problems, in Patent Document 4, the gas introduction pipe has gas outlets at positions corresponding to the respective gaps between the silicon carbide single crystal substrates, and the surfaces of the silicon carbide single crystal substrates are provided with gas outlets. A method for manufacturing an epitaxial silicon carbide wafer has been proposed in which a mixture of a silicon source gas, a carbon source gas, and a doping gas and a rare gas as a carrier gas are supplied to the .

JP-A-8-188408 Japanese Patent Application Laid-Open No. 2010-283336 Japanese Patent Application Laid-Open No. 2011-3885 Japanese Patent Application Laid-Open No. 2014-103188

Materials Science Forum Vols.45-648(2010),pp77-82

However, when substrates are stacked in a conventional hot-wall vertical furnace with the film formation target surface horizontal as in Patent Document 4, SiC is generated in order to supply a sufficient source gas between the substrates. It is necessary to form a pipe in a temperature range, and SiC may be generated and precipitated in the pipe or at the gas outlet, making it difficult to control the gas supply. In addition, since one or more gas outlets and exhaust ports are required between stacked substrates, when the number of stacked substrates increases, the number of gas outlets and exhaust ports to be managed increases, making management difficult. There is In the case where the raw material gas is supplied separately into the silicon material gas and the carbon material gas, the mixture of the raw material gases may be insufficient, and the composition of the raw material gas may not be uniform on the substrate. There is a possibility that the thickness of the deposited film may vary significantly and the film may not have a uniform thickness.

Therefore, in view of the above problems, the present invention prevents SiC from depositing in gas outlets and pipes connected thereto, and alleviates variations in film thickness within the same film formation target surface or between substrates. Therefore, it is an object of the present invention to provide a film forming apparatus and a film forming method capable of forming a film having a more uniform film thickness.

The present inventors have made intensive studies to solve the above problems, and found that, for example, a fixed plate having a linear slit and uniform linear motion of the linear slit are coordinated in a rotating coordinate system. A rotatable disk having a curved slit created by conversion is brought into close contact with the circular disk having a curved slit, and by rotating the disk having the curved slit, an ejection port for ejecting a mixed gas containing a raw material gas and a carrier gas is formed. It is possible to move in the longitudinal direction on a linear slit, thereby preventing deposition of SiC on pipes, etc., and reducing variations in film thickness within the same film formation target surface or between substrates. and completed the present invention. In addition, the inventors have found that the intervals between the plurality of nozzles can be kept constant by transforming the coordinates into a specific rotating coordinate system. Furthermore, in order to further improve the film thickness distribution within the same film formation target surface, it is possible to provide a plurality of gas ejection ports that are fixed without moving, in addition to the ejection ports that move in the linear slit. found to be effective.

That is, the film forming apparatus of the present invention has a rectangular parallelepiped internal shape including a first surface, a second surface facing the first surface, and four side surfaces connecting the first surface and the second surface. a film formation chamber having a film formation chamber, a mixed gas jetting mechanism for jetting a mixed gas containing a raw material gas and a carrier gas from the first surface into the film formation chamber; A mixed gas discharge port for discharging from the film forming chamber, a heater surrounding the four side surfaces to heat the film forming chamber, and a plurality of substrates can be held by stacking the substrates at equal intervals in a non-contact manner. , a substrate holder capable of setting a film-forming target surface of the substrate parallel to the side surface between the first surface and the second surface of the film-forming chamber; an ejection speed control means capable of making the ejection speed of the gas faster than the diffusion speed of the mixed gas, wherein the mixed gas ejection mechanism is a first mixed gas for ejecting the mixed gas into the film forming chamber It has an ejection port, a plurality of second mixed gas ejection ports, and a mixed gas introduction port located outside the deposition chamber for introducing the mixed gas into the first mixed gas ejection port and the second mixed gas ejection port. between a mixed gas introduction pipe, a rectangular opening having a longitudinal direction through which the mixed gas flowing from the mixed gas introduction pipe to the film formation chamber passes, and the first surface and the mixed gas introduction pipe; a disk-shaped rotating plate rotating about the direction of introduction of the mixed gas as a central axis and having a communication port communicating with the first mixed gas ejection port, the mixed gas introduction port, and the opening; The first mixed gas ejection port moves in the longitudinal direction of the opening by the rotating operation, and the second mixed gas ejection port is introduced from the mixed gas introduction port without passing through the communication port. The mixed gas is ejected.

The second mixed gas ejection ports may be arranged at equal intervals on two imaginary straight lines that are parallel to the longitudinal direction of the opening and sandwich the opening at equal intervals.

The communication port may have a curved shape obtained by coordinate-converting the uniform linear motion of the first mixed gas ejection port moving through the opening into a rotating coordinate system.

The film forming apparatus of the present invention may have a plurality of communication ports.

The opening may intersect the central axis of the rotating plate.

A shortest distance between the first mixed gas ejection port and the second mixed gas ejection port and the substrate holder may be 150 mm or more.

Further, in order to solve the above problems, a film forming method of the present invention is a film forming method using the above film forming apparatus of the present invention, wherein the substrates are placed on the substrate holder in a non-contact manner in the film forming chamber. The mixed gas is injected from the first mixed gas outlet and the second mixed gas outlet to a plurality of the substrates stacked at equal intervals with the film formation target surface parallel to the side surface. The mixed gas is discharged from the film formation chamber through the mixed gas discharge port, and the mixed gas is circulated in a direction parallel to the film formation target surface to form a film on the substrate. In the film forming step, the rotating plate rotates about the direction of introduction of the mixed gas as a central axis, and the first mixed gas ejection port is rotated by the rotating operation. The opening is moved longitudinally.

An ejection speed of the mixed gas ejected from the first mixed gas ejection port and the second mixed gas ejection port may be faster than a diffusion speed of the mixed gas.

A film forming method of the present invention is a method for forming a silicon carbide polycrystalline film, the source gas includes a silicon source gas and a carbon source gas, and the silicon source gas includes SiH ₄ , SiH ₃ Cl, and SiH _{2 .} One or two or more selected from the group consisting of Cl ₂ , SiHCl ₃ and SiCl ₄ , and the carbon source gas is one or two or more selected from hydrocarbons having 5 or less carbon atoms. and the carrier gas may be hydrogen gas.

The temperature inside the film formation chamber may be 1400K to 1700K, and the temperature of the first surface may be 1100K or less.

The temperatures of the first mixed gas jetting port and the second mixed gas jetting port may be 1200K or less.

A film forming method of the present invention is a method for forming a silicon carbide single crystal film, the source gas includes a silicon source gas and a carbon source gas, and the silicon source gas includes SiH ₄ , SiH ₃ Cl, and SiH _{2 .} One or two or more selected from the group consisting of Cl ₂ , SiHCl ₃ and SiCl ₄ , and the carbon source gas is one or two or more selected from hydrocarbons having 5 or less carbon atoms. wherein the carrier gas is hydrogen gas, the ratio of the number of carbon atoms in the carbon source gas to the number of silicon atoms in the silicon source gas (C/Si) is set to 0.7 to 1.3, and the substrate is carbonized. A silicon single crystal thin film may be epitaxially grown.

According to the present invention, SiC is prevented from depositing in the gas outlet and the piping connected thereto, and the variation in film thickness within the same film formation target surface or between substrates is alleviated, resulting in a more uniform film thickness. can be provided.

1 is a schematic diagram showing a cross section of a film forming apparatus 1000 according to an embodiment of the present invention as viewed from above; FIG. FIG. 23 is a schematic diagram of a plate 231; It is the front schematic diagram which looked at the rotating plate 240 from the front, and the front schematic diagram of the board 231 when the rotating plate 240 is piled up. FIG. 11 is a diagram illustrating movements of the communication port 241 and the first mixed gas ejection port 210 when the rotating plate 240 is rotated clockwise; FIG. 10 is a diagram illustrating movement of communication ports 241 and 242 and first mixed gas ejection port 210 when rotating plate 240 having communication ports 241 and 242 is rotated clockwise. It is the front schematic which looked at the 2nd surface 120 from the inside of the film-forming chamber 110. FIG. 5 is a schematic diagram of a substrate holder 500. FIG. It is a schematic diagram explaining ejection of mixed gas. 6 is a diagram showing a film thickness measurement portion of a polycrystalline silicon carbide substrate 650. FIG. It is a schematic diagram showing a cross section seen from the upper surface of the film forming apparatus 2000 used in the conventional example. It is the front schematic diagram which looked at the 1st surface 110a in a prior art example from the inside of the film-forming chamber 110. FIG.

An embodiment of a film forming apparatus and a film forming method of the present invention will be described below with reference to the drawings. However, the invention is not limited to these embodiments.

[Deposition apparatus 1000]
FIG. 1 shows a schematic diagram showing a cross section of a film forming apparatus 1000 according to an embodiment of the present invention as viewed from above. The film forming apparatus 1000 includes a film forming chamber 100 , a mixed gas ejection mechanism 200 , a mixed gas outlet 300 , a heater 400 and a substrate holder 500 .

<Deposition chamber 100>
The film forming chamber 100 has a rectangular parallelepiped inner shape consisting of a first surface 110, a second surface 120 facing the first surface 110, and four side surfaces 130 connecting the first surface 110 and the second surface 120. . With the rectangular parallelepiped internal shape, when a plurality of substrates are placed in the deposition chamber 100, the shape of the gap between the substrates and the gap between the substrates and the side surface 130 are the same or similar. Therefore, like the mixed gas flowing between the substrates, the mixed gas flowing between the side surface 130 and the substrate is uniformly distributed toward the mixed gas discharge port 300 from the first mixed gas jet port 210 or the like, which will be described later. can flow. As a result, it is possible to form a uniform film with little variation on the substrate.

For example, if the inner shape of the deposition chamber 100 is cylindrical instead of rectangular parallelepiped, the shape of the gap between the substrates differs greatly from the shape of the gap between the substrates and the side surface 130 . The mixed gas flowing between the substrate and the mixed gas flowing between the side surface 130 and the substrate do not flow uniformly. As a result, the film formed between the substrates and the film formed between the substrate and the side surface 130 become non-uniform, and there is a possibility that films with large variations between the substrates will be formed.

Note that the inner shape of the film formation chamber 100 may be large enough to accommodate the substrate holder 500 and the substrate held by the substrate holder 500, and the mixed gas not involved in the film formation is mixed from the first mixed gas jet port 210 or the like. It is preferable not to provide an extra space that flows toward the gas outlet 300 and is discharged from the deposition chamber 100 .

Moreover, the film forming chamber 100 is preferably made of graphite. Graphite can be easily processed into a rectangular parallelepiped shape, and by forming the film in an inert atmosphere, it can have sufficient durability under high-temperature film forming conditions.

<Mixed gas ejection mechanism 200>
The mixed gas jetting mechanism 200 is a mechanism for jetting a mixed gas containing a raw material gas and a carrier gas from the first surface 110 to the film forming chamber 100 . The mixed gas ejection mechanism 200 has a first mixed gas ejection port 210 and a second mixed gas ejection port 211, a mixed gas introduction pipe 220, a first opening 230, and a rotating plate 240, which will be described below.

(First mixed gas ejection port 210)
The first mixed gas jetting port 210 is a jetting port for jetting the mixed gas into the film forming chamber 100 . The rotation of the rotary plate 240, which will be described later, moves the first opening 230 in the longitudinal direction.

(Second mixed gas ejection port 211)
The second mixed gas jetting port 211 is a jetting port for jetting the mixed gas introduced from the mixed gas introduction port 221 without passing through communication ports 241 and 242 described later. A plurality of second mixed gas ejection ports 211 are provided on, for example, the first surface 110 in correspondence with the second openings 232 .

(Mixed gas introduction pipe 220)
The mixed gas introduction pipe 220 is located outside the film formation chamber 100 and has a mixed gas introduction port 221 for introducing the mixed gas into the first mixed gas jet port 210 and the second mixed gas jet port 211 . Mixed gas flows inside the mixed gas introduction pipe 220, and the mixed gas is introduced from the outside of the film forming apparatus 1000 into the film forming chamber 100 through the first mixed gas jet port 210 and the second mixed gas jet port 211. can be done. In FIG. 1, as the mixed gas introduction pipe 220, a single pipe having a shape in which the diameter of the pipe increases in a tapered manner from the middle of the pipe toward the first mixed gas ejection port 210 is illustrated. is not limited to A plurality of mixed gas introduction pipes 220 may be provided according to the number of the first mixed gas jetting ports 210 and the second mixed gas jetting ports 211, and may not be tapered. In addition, it is preferable that the mixed gas inlet 221 is in close contact with the rotating plate 240 so as not to prevent gas leakage of the mixed gas and prevent rotation of the rotating plate 240 to be described later. The film forming apparatus 1000 may include temperature control means such as a heater capable of appropriately heating the mixed gas introduction pipe 220 or a cooler capable of cooling the mixed gas introduction pipe 220 so that the temperature of the mixed gas introduction pipe 220 can be controlled.

(First opening 230)
The mixed gas flowing from the mixed gas introduction pipe 220 to the film forming chamber 100 passes through the first opening 230 . A schematic diagram of the plate 231 with the first opening 230 in FIG. 1 is shown in FIG. 2(a) is a front view of the plate 231 viewed from the first surface 110 side, and FIG. 2(b) is a schematic cross-sectional view of the plate 231 cut along line AA in FIG. 2(a). FIG. 2(c) is a schematic cross-sectional view of the plate 231 taken along line BB in FIG. 2(a). Although the actual plate 231 or rotating plate 240 is not shown in FIGS. A vertical axis (Y-axis) is attached. The plate 231 is fixed so as not to move, and has a rectangular first opening 230 whose longitudinal direction is the vertical direction. Note that the first opening 230 is not limited to being formed in the plate 231, and the mixed gas ejection port of the first surface 110 also serves as the rectangular first opening 230 whose longitudinal direction is the vertical direction. Alternatively, the mixed gas introduction port 221 may also serve as the rectangular first opening 230 whose longitudinal direction is the vertical direction.

In addition, although FIG. 3A illustrates the first opening 230 whose longitudinal direction is the vertical direction of X=0 passing through the origin, the present invention is not limited to this. For example, the first opening 230 may have a longitudinal direction that passes through the origin and is Y=0, or the first opening 230 that has an arbitrary oblique direction as a longitudinal direction. In addition, although one first opening 230 is illustrated in FIGS. 1 and 3(a), a plurality of first openings 230 may be provided.

In the plate 231, the second openings 232 are parallel to the longitudinal direction of the first openings 230 and are equally spaced on two imaginary straight lines AA and A'A' that sandwich the first openings 230 at equal intervals. are arranged (FIG. 2(a)). Lines AA and A′A′ are imaginary lines and are not attached to the actual plate 231 .

The second mixed gas ejection port 211 is also arranged corresponding to the second opening 232 . That is, they are arranged at equal intervals on two imaginary straight lines that are parallel to the longitudinal direction of the first opening 230 and sandwich the first opening 230 at equal intervals.

The plate 231 has a hollow structure so that the mixed gas can pass from a third opening 233 opened on the back surface to a second opening 232 opened on the front surface, and has a space 234 (Fig. 2(b), (c)). As indicated by arrows in FIGS. 2B and 2C, the mixed gas flowing inside the mixed gas introduction pipe 220 enters the plate 231 from the mixed gas introduction port 221 directly contacting the third opening 233, for example. , is discharged from the second opening 232 . The third opening 233 is formed around the circumference of the rotating plate 240 so that the mixed gas can be continuously ejected without being affected by the rotating plate 240 (described later) arranged on the back surface of the plate 231 . placed outside the On the other hand, the second opening 232 is preferably arranged inside the circumference of the rotating plate 240 so that the mixed gas can be evenly ejected into the film forming chamber 100 . However, the second opening 232 may be arranged outside the circumference of the rotating plate 240 as well as the third opening 233 as long as it does not affect the film formation.

Although three second openings 232 are arranged on two imaginary straight lines in FIG. 2, the present invention is not limited to this. For example, the number of second openings 232 may be large or small, and the second openings 232 may be arranged on three or more imaginary straight lines.

In this way, apart from the first mixed gas jetting ports 210 that move by the rotation of the rotating plate 240, there are a plurality of second mixed gas jetting ports 211 that can continuously jet the mixed gas without being affected by the rotating plate 240. By providing such a film, variations in film thickness within the same film formation target surface or between substrates can be further reduced, and film formation with a more uniform film thickness can be achieved.

(Rotating plate 240)
The rotating plate 240 is located between the first surface 110 and the mixed gas introduction pipe 220, rotates around the direction of introduction of the mixed gas, and rotates around the first mixed gas outlet 210, the mixed gas introduction port 221, It is a disc-shaped plate having a communication port that communicates with the first opening 230 . FIG. 3A shows a schematic front view of the rotating plate 240 in FIG. 1 as viewed from the front. The rotating plate 240 rotates around the origin and has a communication port 241 .

The communication port 241 in FIG. 3( a ) is connected to the first mixed gas jet 210 or the like so that the first mixed gas jet 210 can move from top to bottom in the first opening 230 by uniform linear motion. It has a curved opening obtained by transforming a fast linear motion into a rotating coordinate system. For example, the first opening 230 in FIG. 2(a) has a vertical direction passing through the origin and X=C (C is arbitrary, but C=0 in the case of FIG. 2(a)) as a longitudinal direction. The equation for the uniform linear motion of the first opening 230 is shown in [Equation 1] below.

[Formula 1]
X=C, Y=V×t
(V is speed, t is time)

Converting the uniform linear motion of Equation 1 into rotational coordinates (Xc, Yc) yields the following [Equation 2], and the curved shape of the communication port 241 is obtained.

[Formula 2]
Xc=x*cos(w*t)+y*sin(w*t), Yc=-x*sin(w*t)+y*cos(w*t)
(w is the angular velocity π/T, T is half the cycle time (time for one rotation))

FIG. 3(b) is a schematic front view of a state in which the plate 231 is placed in front of the rotating plate 240, and when the rotating plate 240 is rotated clockwise in this state, the communication port 241 and the FIG. 4 shows the movement of the first mixed gas jetting port 210 . 4, illustration of the second opening 232 and the third opening 233 is omitted. When the rotary plate 240 rotates clockwise by 180 degrees at a constant speed, the communication port 241 rotates from a to d (FIG. 4(a)). The intersection of the first opening 230 and the communication port 241 becomes the first mixed gas ejection port 210, and the first mixed gas ejection port 210 moves from top to bottom in the first opening 230 at a constant speed (Fig. 4(a)). ). At the position of the origin (0, 0), the first opening 230 and the communication port 241 intersect. It can be a structure that does not blow out.

When the rotary plate 240 is rotated 180° It rotates from d to h (FIG. 4(b)). The intersection of the first opening 230 and the communication port 241 becomes the first mixed gas jetting port 210, and the first mixed gas jetting port 210 moves from the bottom to the top of the first opening 230 at a constant speed (Fig. 4 ( b)).

For example, assuming that the coordinates of the upper end of the first opening 230 are (0, a) and the coordinates of the lower end are (0, -a), C = 0, V = 2a/90, w = π/ In the case of 90/sec, the rotating plate 240 can rotate once in 180 seconds. Then, the first mixed gas ejection port 210 moves at a constant speed in the first opening 230 from the upper end coordinates (0, a) to the lower end coordinates (0, -a) in 90 seconds, and then moves at the same speed as the coordinates (0, a ) to the bottom coordinate (0, -a) in 90 seconds.

In Equations 1 and 2, the linear first opening 230 should pass through the origin, and the numerical values can be changed arbitrarily. If the linear first opening 230 does not pass through the origin, a plurality of intersections between the linear first opening 230 and the curved communication port 241 will appear. It may stop moving fast.

Although FIGS. 3 and 4 show a mode in which one communication port 241 is provided, the film forming apparatus may be provided with a plurality of communication ports. For example, as shown in FIG. 5, a curved communication port 242 can be provided in addition to the communication port 241 . In this case, since there are two communication ports, there are two intersections between the first opening 230 and the communication ports 241 and 242, that is, there are two first mixed gas ejection ports 210 (FIG. 5(a)). . Then, when the rotating plate 240 rotates clockwise at a constant speed, the two first mixed gas ejection ports 210 move downward from the upper end and the vicinity of the center of the first opening 230, as indicated by the arrows in FIG. 5(a). move fast. Then, when the rotating plate 240 rotates clockwise at a constant speed from the state in which the rotating plate 240 has been rotated clockwise by 90 degrees (FIG. 5B), two second rotations occur as indicated by the arrows in FIG. 5B. 1 mixed gas ejection port 210 moves downward from the upper end and the vicinity of the center of first opening 230 at a constant speed.

The thickness, side length, and diameter of the plate 231 and the rotating plate 240 can be appropriately set. For example, the thickness can be set to 1 mm to 20 mm, and the side length of the plate 231 and the diameter of the rotating plate 240 can be set smaller than the inner diameter of the outer cylinder 1100 described later.

Plate 231 and rotating plate 240 are preferably made of graphite. Graphite can be easily processed into a plate shape or a disk shape, and can have sufficient durability under high-temperature film formation conditions by setting it in an inert atmosphere during film formation.

Although not shown, the film forming apparatus 1000 also includes a control means such as a personal computer or a microcomputer capable of controlling the rotation conditions of the rotating plate 240, and a motor or engine for driving the rotating plate 240 to rotate. source, etc. can be provided. In addition, it is possible to provide a configuration that allows rotation of the rotating plate 240 such as a rotating shaft, and a configuration that prevents gas leakage of the mixed gas 810 due to rotational driving of a sealing portion or the like.

<Mixed gas outlet 300>
The mixed gas outlet 300 is located at or near the second surface 120 of the film forming chamber 100 and discharges the mixed gas from the film forming chamber 100 . An example of the mixed gas discharge port 300 corresponds to an open end through which the mixed gas is discharged in the mixed gas discharge pipe 310 through which the mixed gas is discharged to the outside. The mixed gas outlet 300 may be located on the second surface 120, and as shown in FIG. It may be outside the film forming chamber 100 assuming that it is not present. The vicinity is, for example, about 20 mm from the second surface 120 as a guideline. In order to control the temperature of the mixed gas discharge port 300 and the mixed gas introduction pipe 220 so that silicon carbide or the like does not precipitate at the mixed gas discharge port 300 and the mixed gas discharge pipe 310, the temperature of a heater that can be appropriately heated or a cooler that can be cooled is adjusted. A control means may be provided.

FIG. 6 shows a schematic front view of the second surface 120 viewed from inside the film forming chamber 100 . In FIG. 6 , one mixed gas outlet 300 is arranged in the center of the second surface 120 . The mixed gas discharge port 300 may be one or more as long as the mixed gas can be discharged without problem even if a film of silicon carbide or the like is formed to some extent. It is preferable to have an opening diameter of about 1/5 to 1/2 of one side of the second surface so that the mixed gas can be discharged without problems.

<Heater 400>
The heater 400 surrounds the four side surfaces 130 of the deposition chamber 100 and heats the deposition chamber 100 . By controlling the heater 400, the temperature of the deposition chamber 100 can be controlled to a temperature suitable for depositing a film on the substrate. As the heater 400, a heater useful for the thermal CVD method can be used, for example, a tubular carbon heater or a Kanthal heater can be used.

<Substrate holder 500>
FIG. 7 shows a schematic diagram of the substrate holder 500. As shown in FIG. 7A is a side view of the substrate holder 500 holding the substrate 600, and FIG. 7B is a front view of the substrate holder 500 inside the deposition chamber 100 viewed from the first surface 110 side. The substrate holder 500 can hold a plurality of substrates 600 by stacking the substrates 600 in a non-contact manner at regular intervals. can be set parallel to the side surface 130 of the film forming chamber 100 .

In FIG. 7, the substrate holder 500 can hold the substrate 600 by sandwiching it from two upper and lower positions with an upper holding rod 510 and a lower holding rod 520 . It has grooves 511 and 521 for holding the . However, the substrate holder is not limited to this, and has holding rods in the front and back in addition to the top and bottom, and can hold the substrate at three or four locations.

The substrate holder 500 participates in film formation by, for example, both the upper holding rod 510 and the lower holding rod 520 being in close contact with the upper side surface 130 a and the lower side surface 130 b of the side surfaces 130 of the film forming chamber 100 . It is possible to prevent the mixed gas from flowing from the first mixed gas outlet 210 and the second mixed gas outlet 211 toward the mixed gas outlet 300 and being discharged from the film forming chamber 100 in large amounts.

In FIG. 7B, the film-forming target surface 610 of the substrate 600 is installed parallel to the left side 130c and the right side 130d of the side surfaces 130 of the film forming chamber 100, and the upper side 130a and the lower side 130b. is installed vertically. However, by changing the shape of the substrate holder 500, the film formation target surface 610 of the substrate 600 can be installed perpendicular to the left side 130c and the right side 130d and parallel to the upper side 130a and the lower side 130b. . That is, the substrates 600 may be stacked vertically or horizontally. However, the film formation target surface 610 is arranged parallel to the first surface 110 and the second surface 120 so that the film formation target surface 610 faces the first mixed gas outlet 210 and the second mixed gas outlet 211 . If the substrates 600 are placed, the mixed gas will not flow uniformly between the substrates, which is not preferable.

Further, the width 700 of the gap between the film formation target surface 610 of the substrate 600 and the left side 130c and the width 710 of the gap between the right side 130d are the same as the width 720 of the gap between the substrates 600 stacked at regular intervals. Then, since the mixed gas uniformly flows through these gaps, it is possible to form a film with little variation in thickness between substrates or on the same film formation target surface.

<Ejection speed of mixed gas>
FIG. 8 shows a schematic diagram for explaining ejection of the mixed gas. It schematically shows the spread of the mixed gas when collisions between molecules in the mixed gas are ignored. Let Vd be the diffusion speed in this case, and Vg be the ejection speed in the case where the mixed gas is pressurized and ejected from the first mixed gas ejection port 210 .

When the diffusion speed Vd is higher than the ejection speed Vg, diffusion of the mixed gas 800 progresses slowly (FIG. 8A), so the supply amount of the raw material gas to the film forming chamber 100 decreases, and the film forming speed slows down. may become In order to prevent the first mixed gas outlet 210 from forming a film with the mixed gas, the temperature of the mixed gas outlet is set to a low temperature (for example, 1200 K or lower), the film formation takes longer because there is a distance for the mixed gas 800 to reach the substrate 600 . The same applies to the ejection speed of the mixed gas from the second mixed gas ejection port 211 .

<Ejection speed control means>
Therefore, the film forming apparatus 1000 of the present invention includes an ejection speed control means capable of making the ejection speed of the mixed gas ejected from the first mixed gas ejection port 210 faster than the diffusion speed of the mixed gas. By setting the ejection velocity Vg faster than the diffusion velocity Vd ( FIG. 8B ), the mixed gas 810 is forcibly discharged from the first mixed gas ejection port 210 . As a result, even when a certain distance is provided between the substrate 600 and the first mixed gas jetting port 210 in the film forming chamber 100, a decrease in the film forming speed can be suppressed. That is, while maintaining a film formation rate equivalent to that of the conventional method, the diameter of the first mixed gas jetting port 210 becomes smaller due to film formation by the mixed gas, and the first mixed gas jetting port 210 is blocked. can be prevented. The same applies to the ejection speed of the mixed gas from the second mixed gas ejection port 211 .

Forcibly discharging the mixed gas 810 from the first mixed gas jetting port 210 in order to make the jetting speed Vg faster than the diffusion speed Vd is, for example, controlled by jetting speed control means such as a regulator, a compressor, or a suction device. It is possible by adjusting by For example, by setting the ejection velocity Vg to 0.4 m/sec or more, the diameter of the first mixed gas ejection port 210 becomes smaller due to the film formation of the mixed gas while maintaining the film formation velocity equivalent to that of the conventional method. In addition, it is possible to easily prevent the first mixed gas ejection port 210 from being clogged. Furthermore, if the ejection speed Vg is 1 m/sec or more, the film formation speed can be clearly increased compared to the conventional method, and the film formation processing time can be shortened more effectively. The same applies to the ejection speed of the mixed gas from the second mixed gas ejection port 211 .

In the film forming apparatus 1000 of the present invention, the shortest distance between the first mixed gas jetting port 210 and the second mixed gas jetting port 211 and the substrate holder 500 is preferably 150 mm or more. Although the optimum shortest distance varies depending on the ejection speed and gas flow rate of the mixed gas 810 and the number of the first mixed gas ejection port 210 and the number of the second mixed gas ejection ports 211, if the shortest distance is 150 mm or more, it is possible to achieve success. The temperature around the first mixed gas outlet 210 and the second mixed gas outlet 211 can be made sufficiently lower than the film formation temperature around the substrate 600 in the film chamber 100 . As a result, the diameter of the first mixed gas jetting port 210 or the second mixed gas jetting port 211 becomes smaller due to film formation of the mixed gas, and the first mixed gas jetting port 210 or the second mixed gas jetting port 211 becomes smaller. It is possible to easily prevent clogging.

(Other configurations)
The film forming apparatus 1000 according to one embodiment of the present invention may have a further configuration in addition to the configuration described above. For example, as shown in FIG. 1, a cylindrical outer cylinder 1100 made of carbon, for example, in which the film forming chamber 100 is inserted, and inside the outer cylinder 1100, the film forming chamber 100 has a first surface 110 and a second surface 120. A holding jig 1200 fixed from the outside of the ceramic furnace core tube 1300, the outer cylinder 1100, and the ceramic furnace core tube 1300 for circulating an inert gas such as Ar gas are inserted inside, and the outer cylinder 1100 is inserted inside. A housing 1500 may be provided to house the deposition chamber 100 together with the outer cylinder 1100 and the ceramic furnace core tube 1300 . Also, although not shown, temperature measurement such as a thermometer for measuring the temperature inside the film forming chamber 100, the temperature of the first surface 110, and the temperature of the first mixed gas jet port 210 and the second mixed gas jet port 211 A control means such as a switch for controlling heat generation of the heater 400, a power supply for generating heat, and the like can be provided.

[Deposition method]
Next, a film forming method using the film forming apparatus 1000 will be described as an example of the film forming method of the present invention. A film forming method of the present invention includes a film forming step.

<Film formation process>
In the film formation process, in the film formation chamber 100, the substrates 600 are stacked on the substrate holder 500 at regular intervals in a non-contact manner, and the film formation target surface 610 is set parallel to the side surface 130. The mixed gas 810 is ejected from the first mixed gas ejection port 210 and the second mixed gas ejection port 211 into the film formation chamber 100, and the mixed gas 810 is discharged from the film formation chamber 100 from the mixed gas discharge port 300. In this step, a film is formed on the substrate 600 by circulating the liquid 810 in a direction parallel to the film formation target surface 610 . By forming the film in this way, it is possible to form a film with little variation in thickness between substrates or on the same film formation target surface.

Further, the width 700 of the gap between the film formation target surface 610 of the substrate 600 and the left side 130c and the width 710 of the gap between the right side 130d are the same as the width 720 of the gap between the substrates 600 stacked at regular intervals. Then, since the mixed gas uniformly flows through these gaps, it is possible to form a film with less variation in thickness between substrates or on the same film formation target surface.

Further, as described with reference to FIGS. 3 to 5 and the like, in the film forming method of the present invention, the rotating plate 240 rotates about the direction in which the mixed gas 810 is introduced as the central axis in the film forming process. 1 mixed gas jet 210 moves longitudinally in the first opening 230 by this rotational movement.

For example, as described using FIG. 8, the ejection speed Vg of the mixed gas 810 ejected from the first mixed gas ejection port 210 and the second mixed gas ejection port 211 is set to be faster than the diffusion speed Vd of the mixed gas 810. preferably.

The film forming method of the present invention includes, for example, a method for forming a polycrystalline silicon carbide film. In this case, the silicon source gas and the carbon source gas, which are the raw materials of silicon carbide, are the raw material gases, and the raw material gas and the rare gas such as argon gas and helium gas, hydrogen gas, etc., which have the role of transporting these raw material gases. A mixed gas 810 is obtained by mixing these carrier gases. Mixed gas 810 may further optionally include a dopant gas such as nitrogen gas or argon gas.

The silicon source gas is not particularly limited as long as a silicon carbide polycrystalline film can be formed on the substrate 600 without any problem. For example, one or more selected from the group consisting of monomers SiH ₄ , SiH ₃ Cl, SiH ₂ Cl ₂ , SiHCl ₃ and SiCl ₄ can be used as the silicon source gas.

Further, the carbon source gas is not particularly limited as long as a silicon carbide polycrystalline film can be formed on the substrate 600 without any problem. Since it is in a gaseous state near room temperature and is convenient for handling, it is preferably a carbon source gas composed of a saturated hydrocarbon having 5 or less carbon atoms or an unsaturated hydrocarbon having 5 or less carbon atoms. , one or a mixture of two or more thereof can be suitably used. In particular, it is one or more selected from hydrocarbons having 5 or less carbon atoms, and methane, ethane, propane, butane, and similar hydrocarbon gases can be appropriately used as the carbon source gas.

When forming a silicon carbide polycrystalline film, it is preferable to set the temperature in film forming chamber 100 to 1400 K to 1700 K and the temperature of first surface 110 to 1100 K or lower. The temperature in film formation chamber 100 is an important condition for forming a polycrystalline silicon carbide film on substrate 600 . If the temperature in the chamber is low, the silicon carbide polycrystalline film may not be formed, or the film formation rate may be slowed, resulting in a decrease in manufacturing efficiency. Furthermore, a large amount of raw material gas that does not participate in the film formation is discharged from the film forming chamber, which may increase the loss of the raw material gas. Moreover, if the temperature in the chamber is high, epitaxial growth may occur, and the film formation target surface 610 close to the first mixed gas jet port 210 and the second mixed gas jet port 211 corresponding to the upstream side of the mixed gas 810 may not be deposited. Therefore, it may be difficult to form a film on the film formation target surface 610 close to the mixed gas outlet 300 corresponding to the downstream side of the mixed gas 810, and the film thickness of the silicon carbide polycrystalline film on the same film formation target surface 610 may be increased. There is a risk of significant variation. By setting the temperature in the film forming chamber 100 to 1400 K to 1700 K, it is possible to form a silicon carbide polycrystalline film uniformly without lowering the production efficiency.

Then, the temperature of the first surface 110 does not increase due to the deposition of the polycrystalline silicon carbide film on the first mixed gas ejection port 210 and the second mixed gas ejection port 211, and therefore the ejection of the mixed gas 810 does not occur. This is an important condition for preventing control from becoming difficult. If the temperature of the first surface 110 is high, a polycrystalline silicon carbide film may be deposited on the first mixed gas ejection port 210 or the second mixed gas ejection port 211, making it difficult to control the ejection of the mixed gas 810. , the first mixed gas outlet 210 and the second mixed gas outlet 211 may be blocked. Although there is no problem even if the temperature of the first surface 110 is low, it may become difficult to control the temperature inside the film forming chamber 100 due to the low temperature of the first surface 110 . Considering these points, it is preferable to set the temperature of the first surface 110 to 1100K or less, more preferably about 600K to 1000K.

Furthermore, when forming a silicon carbide polycrystalline film, it is preferable to set the temperature of the first mixed gas outlet 210 and the second mixed gas outlet 211 to 1200 K or lower. The temperature of the first mixed gas jet port 210 and the second mixed gas jet port 211 does not increase due to the deposition of the silicon carbide polycrystalline film on the first mixed gas jet port 210 and the second mixed gas jet port 211 to prevent blockage. , and is also an important condition for preventing difficulty in controlling ejection of the mixed gas 810 . If the temperature of the first mixed gas jet port 210 or the second mixed gas jet port 211 is high, a silicon carbide polycrystalline film will be deposited on the first mixed gas jet port 210 or the second mixed gas jet port 211, and the mixed gas will There is a risk that the ejection of 810 will be difficult to control, and that the first mixed gas ejection port 210 and the second mixed gas ejection port 211 will be blocked. Although there is no problem even if the temperature of the first mixed gas jetting port 210 or the second mixed gas jetting port 211 is low, it is difficult to control the temperature inside the film forming chamber 100 because the temperature of the first surface 110 becomes low. There is a risk of becoming. Considering these points, it is preferable to set the temperature of the first mixed gas jet port 210 and the second mixed gas jet port 211 to 1200K or less, more preferably about 600K to 1000K.

The film thickness of the silicon carbide polycrystalline thin film grown on the film formation target surface 610 of each substrate 600 can be appropriately set, and is not particularly limited. Generally, the film thickness can be in the range of about 0.2 to 5 mm.

Further, the film forming method of the present invention includes a method for forming a silicon carbide single crystal film. In this case, the silicon source gas and the carbon source gas, which are the raw materials of silicon carbide, are the raw material gases, and the raw material gas and the rare gas such as argon gas and helium gas, hydrogen gas, etc., which have the role of transporting these raw material gases. A mixed gas 810 is obtained by mixing these carrier gases. Mixed gas 810 may further optionally include a dopant gas such as nitrogen gas or argon gas.

The silicon source gas is not particularly limited as long as a silicon carbide polycrystalline film can be formed on the substrate 600 without any problem. For example, one or more selected from the group consisting of monomers SiH ₄ , SiH ₃ Cl, SiH ₂ Cl ₂ , SiHCl ₃ and SiCl ₄ can be used as the silicon source gas.

Further, the carbon source gas is not particularly limited as long as a silicon carbide polycrystalline film can be formed on the substrate 600 without any problem. Since it is in a gaseous state near room temperature and is convenient for handling, it is preferably a carbon source gas composed of a saturated hydrocarbon having 5 or less carbon atoms or an unsaturated hydrocarbon having 5 or less carbon atoms. , one or a mixture of two or more thereof can be suitably used. In particular, it is one or more selected from hydrocarbons having 5 or less carbon atoms, and methane, ethane, propane, butane, and similar hydrocarbon gases can be appropriately used as the carbon source gas.

Furthermore, when forming a silicon carbide single crystal film, the ratio (C/Si) of the number of carbon atoms in the carbon source gas to the number of silicon atoms in the silicon source gas (C/Si) is important. By controlling the ratio to 7 to 1.3, epitaxial growth of a silicon carbide single crystal thin film on the substrate 600 is facilitated, and the growth rate can be increased, leading to an improvement in productivity. If C/Si deviates from 0.7 to 1.3, the ratio of silicon atoms and carbon atoms will be out of balance, which may make film formation difficult or slow down the film formation speed. , there is a possibility that the raw material gas that does not participate in the film formation increases and is wasted. For example, if C/Si is less than 0.7, unreacted Si may adhere (droplet) to the film in a metallic state, causing defects. Moreover, when C/Si exceeds 1.3, there is a possibility that surface steps called bunching may occur, which may adversely affect device fabrication. More preferably, C/Si is 0.8 to 1.2.

The growth rate of the silicon carbide single crystal thin film is preferably 10 μm/hour to 70 μm/hour, and the silicon material gas at that time has a concentration of 1% by volume of the silicon source gas mentioned as a suitable example above. ~10% by volume, preferably between 2% and 4% by volume. On the other hand, for the carbon material gas, the concentration of the carbon source gas mentioned as a suitable example is preferably 0.01% by volume to 1% by volume or less, preferably 0.02% by volume to 0.06% by volume. % by volume. It should be noted that this concentration range is illustrated for the case of C ₃ H ₈ as an example, and using this concentration range as a guideline, when using another carbon source gas, the amount of carbon (C) is equivalent. should be changed so that For example, if methane (CH ₄ ) is used, the upper and lower limits of this concentration range should be tripled.

As for the growth pressure of the silicon carbide single-crystal thin film, the general conditions for CVD growth of the silicon carbide thin film can be adopted as they are, as with the growth temperature. For example, the growth pressure should be in the range of 10,000 Pa to 110,000 Pa.

It should be noted that the film forming method of the present invention is not limited to the method for forming a silicon carbide polycrystalline film or a silicon carbide single crystal film. For example, this method is also useful for forming films of titanium nitride, aluminum nitride, titanium carbide, diamond-like carbon, and the like.

(Other processes)
The film forming method of the present invention can include other steps in addition to the film forming steps described above. For example, a step of stacking the substrates 600 on the substrate holder 500 at regular intervals without contact and placing the substrates 600 on the substrate holder 500, a step of placing the substrate holder 500 with the substrates 600 placed thereon in the deposition chamber 100, A process of starting up the film forming apparatus 1000 in a state ready for film formation, a process of cooling the film forming chamber after the film forming process, and a process of taking out the substrate after film formation from the film forming chamber 100, and the like are included.

Further, in the film forming method of the present invention, a plurality of support substrates such as Si substrates or C substrates can be used as substrates 600, and silicon carbide polycrystalline thin films can be grown on each of the film forming target surfaces 610 thereof. The number of substrates 600 in one film formation process is not particularly limited, but films can be formed on 5 to 10 substrates to 20 to 30 or more substrates 600 at the same time. Note that the substrate 600 is not limited to the support substrate, and any substrate suitable for film formation can be selected as appropriate and used as the substrate.

Hereinafter, the present invention will be described more specifically based on examples and comparative examples. In addition, the present invention is not limited to the following contents.

[Example 1]
Nine carbon substrates having a diameter of 4 inches (100 mm) and a thickness of 1 mm were prepared as the substrate 600, and the film forming apparatus 1000 shown in FIG. A film-forming step of forming a silicon carbide polycrystalline film was carried out. After the film formation step, the state of precipitation of silicon carbide at first mixed gas jet port 210 and second mixed gas jet port 211 was confirmed, and the film thickness of the formed polycrystalline silicon carbide film was measured. Variability was evaluated.

(Deposition apparatus 1000)
The outer cylinder 1100 has a cylindrical shape formed from a double-ended graphite crucible and is inserted into the ceramic furnace core tube 1300 . Both ends of the ceramic furnace core tube 1300 and the outer cylinder 1100 are sealed with metal fixed flanges 1400 . A film forming chamber 100 is fixed inside the outer cylinder 1100 by a holding jig 1200 . The mixed gas introduction pipe 220 made of graphite has a mixed gas introduction port 221 that introduces the mixed gas 810 into the first mixed gas ejection port 210 and the second mixed gas ejection port 211, and the mixed gas introduction port 221 serves as a holding jig. It is installed by being inserted into the tool 1200 . A plate 231 and a rotating plate 240 are installed between the first surface 110 and the mixed gas introduction pipe 220 . The mixed gas discharge pipe 310 made of graphite is installed by being inserted into the holding jig 1200 and the second surface 120 so that the mixed gas discharge port 300 is positioned inside the film formation chamber 100 . A cylindrical graphite heater 400 surrounding the ceramic furnace core tube 1300 is installed, and a housing 1500 is provided to house the deposition chamber 100 together with the outer cylinder 1100 and the ceramic furnace core tube 1300 . The mixed gas 810 supplied to the film forming chamber 100 can be discharged from the film forming apparatus 1000 to the outside using a vacuum pump (not shown) connected to the mixed gas discharge pipe 310 .

In the film forming apparatus 1000, the ceramic furnace core tube 1300 has an outer diameter of 210 mm, an inner diameter of 190 mm, a uniform thickness, and a length of 700 mm. The outer cylinder 1100 has an outer diameter of 180 mm, an inner diameter of 170 mm, a uniform thickness, and a length of 700 mm. The film forming chamber 100 has an outer shape of a rectangular parallelepiped of 118 mm square and a length of 320 mm, an inner shape of a rectangular parallelepiped of 110 mm square and a length of 320 mm, and has a uniform thickness.

(plate 231)
The plate 231 is made of carbon and has a length and width of 120 mm and a thickness of 10 mm. . In addition, the plate 231 is parallel to the longitudinal direction of the first opening 230, and is arranged on two imaginary straight lines AA and A′A′ that sandwich the opening 230 at equal intervals. Three openings 232 were provided. The intervals between the imaginary straight lines AA and A′A′ are each 4 cm from the first opening 230, and the intervals between the second openings 232 on the same imaginary straight line are equal intervals of 4 cm at the center of the circle. Among the three second openings 232 arranged on the imaginary straight line, the center of the circle of the middle second opening 232 was arranged on the X-axis. Furthermore, the second openings 232 are all arranged inside the circumference of the rotating plate 240 . The third openings 233 had an inner diameter of 8 mm, and were arranged near the four corners of the plate 231 and outside the circumference of the rotating plate 240 . The plate 231 was positioned between the rotating plate 240 and the first surface 110 of the film forming chamber 100 and fixed outside the film forming chamber 100 . Note that the center of the plate 231 and the center of the rotating plate 240 are arranged so as to coincide with each other.

(Rotating plate 240)
The rotating plate 240 is made of carbon and has a diameter of 120 mm and a thickness of 10 mm. One having a communication opening 241 opening in a curved line obtained by coordinate transformation of linear motion into a rotating coordinate system was used (FIG. 3(a)). Specifically, the opening 230 in FIG. 2(a) has a vertical direction passing through the origin and having X=0 as its longitudinal direction. , as shown in [Equation 3] below. Let the coordinates of the upper end of the opening 230 passing through the center (origin (0, 0)) be (0, a) and the coordinates of the lower end be (0, -a) (FIG. 4). Since the opening is 100 mm in the direction, a is 50 mm. In Equation 3, the first mixed gas jetting port 210 moves at a constant speed in 10 minutes from the coordinates (0, 50 mm) of the upper end of the opening 230 to the coordinates (0, -50 mm) of the lower end (Y = -V x t + 50 ), and then the first mixed gas jet port 210 moves at a constant speed (Y=V×t−50) in 10 minutes from the coordinates of the lower end (0, −50 mm) to the coordinates of the upper end (0, 50 mm). bottom.

[Formula 3]
X=0
From top coordinate (0, 50mm) to bottom coordinate (0, -50mm): Y=-V×t+50
From the coordinates of the lower end (0, -50mm) to the coordinates of the upper end (0, 50mm): Y = V x t-50
V=10mm/min
(V is speed, t is time)

Converting the uniform linear motion of Equation 3 into rotational coordinates (Xc, Yc) yields the following [Equation 4], and the curved shape of the communication port 241 is formed based on [Equation 4]. In Equation 4, the angular velocity w is 180 degrees/60 seconds, or 3 degrees/second. The width of the communication port 241 was set to 10 mm.

[Formula 4]
Xc=x*cos(w*t)+y*sin(w*t)=y*sin(w*t), Yc=y*cos(w*t) w=π/min (w is angular velocity π/ T, T is half the cycle time (time for one rotation))

When the rotary plate 240 is rotated once in 20 minutes at a constant speed, the first mixed gas jetting port 210 reaches the coordinates of the upper end of the opening 230 ( 0, 50 mm) to the lower end coordinates (0, −50 mm) at a constant speed. After that, within 10 minutes after the rotating plate 240 makes one turn from half a turn, the first mixed gas jetting port 210 moves from the coordinates (0, −50 mm) of the lower end of the opening 230 to the coordinates (0, 50 mm) of the upper end, and so on. moved fast. The mixed gas 810 jetted from the second mixed gas jet port 211 was not affected by the rotation of the rotating plate 240, and the mixed gas 810 was continuously jetted.

(Installation of substrate 600)
Nine substrates 600 were placed on the substrate holder 500 as in the embodiment shown in FIG. The substrate 600 was placed in the deposition chamber 100 while being fixed to the substrate holder 500 by the grooves 511 and 521 . As shown in FIG. 7B, the upper holding bar 510 of the substrate holder 500 is brought into close contact with the upper side surface 130a so that the mixed gas 810 does not enter between the substrate holder 500 and the lower holding bar 520. It is brought into close contact with the lower surface 130b so that the mixed gas 810 does not enter between it and the lower surface 130b. The width 700 of the gap between the film formation target surface 610 of the substrate 600 and the left side 130c and the width 710 of the gap between the right side 130d are the same as the width 720 of the gap between the substrates 600 stacked at equal intervals, Each was 10 mm. The shortest distance between the first mixed gas jetting port 210 and the second mixed gas jetting port 211 and the substrate holder 500 was set to 150 mm.

(Deposition of silicon carbide polycrystalline film)
Ar gas was flowed between the outer cylinder 1100 and the ceramic furnace core tube 1300 and inside the housing 1500 to prevent oxidation of the graphite material. After the inside of the film forming chamber 100 is evacuated by a vacuum pump (not shown), the mixed gas introduction pipe 220 is used to introduce hydrogen gas into the film forming chamber 100 at a flow rate of 200 cm ³ per minute. The internal pressure was adjusted to atmospheric pressure (101,325 Pa). After that, while maintaining the pressure constant, the temperature of the first surface 110 is maintained at 1100 K or less, and the temperature of the first mixed gas jet port 210 and the second mixed gas jet port 211 is maintained at 1200 K or less. was raised to 1550K. Then, the flow rate of hydrogen gas introduced into the film forming chamber 100 was increased to 6.5 liters per minute. After maintaining this state for 3 minutes, this hydrogen gas was mixed with 0.65 liters/minute of SiCl ₄ gas, 0.65 liters/minute of CH ₄ gas, and 3.2 liters/minute of argon gas to obtain a mixed gas 810 with Vg>Vd. In this state, the formation of a polycrystalline silicon carbide film on the substrate 600 by thermal CVD was started.

After the film formation process was performed for 40 hours, the supply of the mixed gas 810 and the heating by the heater 400 were stopped to cool the substrate 600 to room temperature. Then, the substrates 600 are exposed by grinding the outer periphery, and the substrates 600 are baked in the air to be ashed. got a piece Silicon carbide is not adhered to first mixed gas ejection port 210, second mixed gas ejection port 211, mixed gas introduction pipe 220, first opening 230, and rotating plate 240, which constitute mixed gas ejection mechanism 200. , confirmed that there was no abnormality in the ejection of the mixed gas 810.

(Measurement of Film Thickness of Silicon Carbide Polycrystalline Substrate 650)
The film thickness of silicon carbide polycrystalline substrate 650 was measured using an oblique incidence optical measuring instrument. As shown in FIG. 9, nine measurements were taken on each substrate. Here, location No. 1 is the center of polycrystalline silicon carbide substrate 650, location No. 8 is on the upper side surface 130a side, location No. 6 is on the lower side surface 130b side, and location No. 7 is the first mixed gas jet port. 210 side, No. 9 is the mixed gas outlet 300 . The 4th point is equidistant from the 1st and 8th points, and is located on a straight line connecting the 1st and 8th points. The 3rd, 2nd and 5th locations are the same as the 4th location. Table 1 shows the average value of the film thickness measured at the same location on two polycrystalline silicon carbide substrates 650 obtained from the same substrate 600, and the film thickness of polycrystalline silicon carbide substrate 650 calculated from this average value. Mean values are shown.

[Comparative example]
Example 1 A silicon carbide polycrystalline film was formed under the same conditions as in , and the film thickness was measured. After the film formation, it was confirmed that no silicon carbide adhered to the first mixed gas jetting port 210 and the mixed gas introduction pipe 220, and that the jetting of the mixed gas 810 was normal. Similar to Example 1, Table 1 shows the measurement results of the film thickness.

[Conventional example]
In the conventional example, a silicon carbide polycrystalline film was formed under the same conditions as in Example 1 except that the film forming apparatus 2000 shown in FIG. 10 was used, and the film thickness was measured. After the film formation, it was confirmed that no silicon carbide adhered to the mixed gas jetting port 210a and the mixed gas introducing pipe 220a, and that the jetting of the mixed gas 810 was normal. Similar to Example 1, Table 1 shows the measurement results of the film thickness.

The film forming apparatus 2000 will be described below. In the film forming apparatus 2000, instead of the mixed gas ejection mechanism 200, four mixed gas introduction pipes 220a pass through the outer cylinder 1100, the holding jig 1200, and the first surface 110a from the outside of the fixed flange 1400 to form the film forming chamber. 100 was installed so that the mixed gas ejection port 210a was arranged.

FIG. 11 is a schematic front view of the first surface 110a of the film forming apparatus 2000 viewed from inside the film forming chamber 110. FIG. As shown in FIG. 11, four mixed gas ejection ports 210a each having an inner diameter of 12 mm are arranged on the first surface 110a. The four mixed gas jets 210a are arranged at equal intervals of 22 mm at the center of the pipe, and the mixed gas jets 210a are arranged in a row in the center of the first surface 110 in the width direction (direction perpendicular to the row). placed. In addition, in the film forming apparatus 2000 , the same reference numerals as in the film forming apparatus 1000 are assigned the same components as in the film forming apparatus 1000 .

In the conventional example, variations in film thickness were observed within the same film formation target surface and between substrates. In the comparative example, such variations are more moderated than in the conventional example, and in the example, variations in film thickness within the same film-forming target surface or between substrates are further moderated more than in the comparative example. As a result, it was confirmed that, in the example, it was possible to form a polycrystalline silicon carbide film having a more uniform film thickness than in the conventional example and the comparative example.

[summary]
As described above, according to the film forming apparatus and film forming method of the present invention, it is possible to prevent the deposition of silicon carbide in the gas outlet and the piping connected thereto, and prevent the deposition of silicon carbide in the same film forming target surface or between substrates. It is clear that it is possible to further reduce the variation in the film thickness in 1, and to form a film with a more uniform film thickness.

REFERENCE SIGNS LIST 100 Film formation chamber 110 First surface 110a First surface 120 Second surface 130 Side surface 130a Upper surface 130b Lower surface 130c Left surface 130d Right surface 200 Mixed gas ejection mechanism 210 First mixed gas ejection port 211 Second mixed gas ejection port 210a Mixed gas ejection port 220 Mixed gas introduction pipe 220a Mixed gas introduction pipe 221 Mixed gas introduction port 230 First opening 231 Plate 232 Second opening 233 Third opening 234 Space 240 Rotating plate 241 Communication port 242 Communication port 300 Mixed gas Exhaust port 310 Mixed gas exhaust pipe 400 Heater 500 Substrate holder 510 Upper holding bar 511 Groove 520 Lower holding bar 521 Groove 600 Substrate 610 Film formation target surface 650 Silicon carbide polycrystalline substrate 700 Width 710 Width 720 Width 800 Mixed gas 810 Mixed gas 1000 Film forming apparatus 1100 Outer cylinder 1200 Holding jig 1300 Ceramic furnace core tube 1400 Fixed flange 1500 Housing 2000 Film forming apparatus Vg Ejection velocity Vd Diffusion velocity

Claims (12)

a deposition chamber having a cuboid inner shape comprising a first surface, a second surface facing the first surface, and four side surfaces connecting the first surface and the second surface;
a mixed gas ejection mechanism for ejecting a mixed gas containing a raw material gas and a carrier gas from the first surface into the film forming chamber;
a mixed gas discharge port on or near the second surface for discharging the mixed gas from the film forming chamber;
a heater that surrounds the four side surfaces and heats the deposition chamber;
A plurality of substrates can be held by stacking the substrates at equal intervals without contact, and the film formation target surface of the substrate is positioned between the first surface and the second surface of the film formation chamber. A substrate holder that can be installed parallel to the side surface,
an ejection speed control means capable of making the ejection speed of the mixed gas ejected into the film formation chamber faster than the diffusion speed of the mixed gas,
The mixed gas ejection mechanism is
a first mixed gas ejection port and a plurality of second mixed gas ejection ports for ejecting the mixed gas into the film forming chamber;
a mixed gas introduction pipe located outside the deposition chamber and having a mixed gas introduction port for introducing the mixed gas into the first mixed gas ejection port and the second mixed gas ejection port;
a rectangular opening having a longitudinal direction through which the mixed gas flowing from the mixed gas introduction pipe to the film formation chamber passes;
It is located between the first surface and the mixed gas introduction pipe, rotates about the direction of introduction of the mixed gas as a central axis, and moves the first mixed gas ejection port, the mixed gas introduction port, and the opening. a disk-shaped rotating plate having a communicating port,
The first mixed gas ejection port moves in the longitudinal direction of the opening due to the rotational movement,
The film forming apparatus, wherein the second mixed gas ejection port ejects the mixed gas introduced from the mixed gas introduction port without passing through the communication port. 2. The composition according to claim 1, wherein the second mixed gas ejection ports are arranged at equal intervals on two imaginary straight lines that are parallel to the longitudinal direction of the opening and sandwich the opening at equal intervals. membrane device. 3. The communication port according to claim 1 or 2, wherein said communication port opens in a curved shape obtained by coordinate-converting uniform linear motion of said first mixed gas ejection port moving in said opening into a rotating coordinate system. Deposition equipment. 4. The film forming apparatus according to claim 1, comprising a plurality of communication ports. 5. The film forming apparatus according to claim 1, wherein said opening intersects the central axis of said rotating plate. 6. The film forming apparatus according to claim 1, wherein a shortest distance between said first mixed gas outlet and said second mixed gas outlet and said substrate holder is 150 mm or more. A film forming method using the film forming apparatus according to any one of claims 1 to 6,
In the deposition chamber, the first mixed gas is applied to the plurality of substrates, which are stacked on the substrate holder at regular intervals in a non-contact manner, and the deposition target surface is set parallel to the side surface. The mixed gas is ejected from the ejection port and the second mixed gas ejection port into the film formation chamber, and the mixed gas is discharged from the film formation chamber from the mixed gas discharge port to perform the film formation. A film forming step of forming a film on the substrate by circulating in a direction parallel to the target surface,
In the film formation step, the rotating plate rotates about the direction in which the mixed gas is introduced, and the first mixed gas ejection port moves the opening in the longitudinal direction due to the rotating operation. Deposition method. 8. The film forming method according to claim 7, wherein an ejection speed of said mixed gas ejected from said first mixed gas ejection port and said second mixed gas ejection port is faster than a diffusion speed of said mixed gas. In the method for forming a silicon carbide polycrystalline film, the source gas includes a silicon source gas and a carbon source gas, and the silicon source gas includes SiH ₄ , SiH ₃ Cl, SiH ₂ Cl ₂ , SiHCl ₃ and SiCl. ₄ , the carbon source gas is one or more selected from hydrocarbons having 5 or less carbon atoms, and the carrier gas is hydrogen gas. The film forming method according to claim 7 or 8, wherein 10. The film forming method according to claim 9, wherein the temperature inside said film forming chamber is 1400K to 1700K, and the temperature of said first surface is 1100K or less. 11. The film forming method according to claim 9, wherein the temperature of said first mixed gas outlet and said second mixed gas outlet is 1200K or lower. In the method for forming a silicon carbide single crystal film, the source gas includes a silicon source gas and a carbon source gas, and the silicon source gas includes SiH ₄ , SiH ₃ Cl, SiH ₂ Cl ₂ , SiHCl ₃ and SiCl. ₄ , the carbon source gas is one or more selected from hydrocarbons having 5 or less carbon atoms, and the carrier gas is hydrogen gas. and
The silicon carbide single crystal thin film is epitaxially grown on the substrate by setting the ratio (C/Si) of the number of carbon atoms in the carbon source gas to the number of silicon atoms in the silicon source gas to 0.7 to 1.3. 9. The film forming method according to 7 or 8.

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