JP2006070342A - Vapor phase film deposition system, susceptor and vapor phase film deposition method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor phase film deposition system, a susceptor and a vapor phase film deposition method capable of optimizing the temperature conditions of a substrate. <P>SOLUTION: The vapor phase film deposition system is provided with: a treatment vessel 2; a susceptor 10; and high frequency coils 4. The susceptor 10 is arranged at the inside of the treatment vessel 2, and holds a substrate 12. The high frequency coils 4 each form a magnetic field for subjecting the susceptor 10 to induction heating. Each high frequency coil 4 has a coiled shape with the central axis in a direction shown by an arrow 13 as the center. To the direction to which the central axis of each high frequency coil 4 elongates, the direction to which the surface holding the substrate 12 in the susceptor 10 is crossed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vapor deposition apparatus, a susceptor, and a vapor deposition method, and more specifically, a vapor deposition apparatus, a susceptor, and a vapor deposition that can improve the uniformity of deposition conditions. Regarding the method.

Conventionally, a vapor deposition apparatus such as a CVD (Chemical Vapor Deposition) apparatus is known as an apparatus for forming an epitaxial thin film or the like. In such a vapor deposition apparatus, a susceptor for holding a substrate or the like that is a target for forming a film is used (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 10-12364

  In the vapor phase film forming apparatus as described above, it is required to uniformly heat the substrate surface in order to realize uniform film formation on the substrate during film formation. In order to realize such uniform heating of the substrate, for example, in Patent Document 1, in the direction parallel to the magnetic field generated by the coil for inductively heating the susceptor and opposite to the surface supporting the substrate. A susceptor having a groove formed on the back surface is disclosed. In Patent Document 1, the susceptor is configured as described above, whereby the temperature distribution of the susceptor on the surface that supports the substrate is made uniform, and as a result, the substrate surface can be heated uniformly.

  However, in the conventional vapor phase film forming apparatus as described above, when the configuration and arrangement of the coil and the susceptor are determined, the heat generation density distribution in the susceptor is determined. If the heat dissipation characteristics at the susceptor change due to changes in process conditions (more specifically, the thermal conditions around the susceptor), the heat density distribution at the susceptor is corrected in response to such changes in the heat dissipation characteristics. It was difficult to do. For this reason, when a change in process conditions occurs, it is difficult to realize an appropriate substrate temperature condition.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to optimize the temperature conditions of the substrate even when the process conditions change. It is to provide a possible vapor deposition apparatus, susceptor and vapor deposition method.

  A vapor deposition apparatus according to the present invention includes a processing container, a susceptor, and a coil. The susceptor is disposed inside the processing container and holds the substrate. The coil forms a magnetic field for inductively heating the susceptor. The coil is wound around a central axis. The extending direction of the surface holding the substrate in the susceptor intersects the extending direction of the central axis of the coil.

  In this case, if the extending direction of the surface holding the substrate in the susceptor intersects the extending direction of the central axis of the coil (that is, the susceptor is inclined with respect to the central axis of the coil), the heat generation density due to induction heating in the susceptor The distribution of changes. For this reason, the balance between heat generation and heat dissipation in the susceptor can be optimized by changing the angle θ formed by the direction in which the surface holding the substrate in the susceptor extends with respect to the direction in which the central axis of the coil extends. As a result, the temperature distribution of the substrate mounted on the susceptor (particularly the temperature distribution in the direction in which the central axis of the coil extends) can be made uniform.

  The vapor deposition apparatus may further include a gantry that holds the susceptor so that the direction in which the surface of the susceptor holds the substrate intersects the direction in which the central axis of the coil extends. In this case, the susceptor can be held in an inclined state so that the extending direction of the surface holding the substrate in the susceptor intersects the extending direction of the central axis of the coil by a simple method of mounting the susceptor on the mount. Moreover, by preparing a plurality of types of mounts with different inclination angles of the portion on which the susceptor is mounted, by selecting and using one of the plurality of types of mounts, the angle θ can be easily changed. be able to.

  The vapor phase film forming apparatus may further include a reaction gas supply member for circulating the reaction gas inside the processing container. Further, the planar shape of the substrate may be circular. The planar shape of the susceptor is an end located on the upstream side of the flow of the reaction gas flowing through the inside of the processing vessel, and is a straight upstream side wall part, and an arcuate corner part connected to both ends of the upstream side wall part, It may comprise an arcuate portion that is an end located on the downstream side of the flow of the reaction gas, and a side wall portion that connects both ends of the arcuate portion and arcuate corner portions that are connected to both ends of the upstream side wall portion. Good. The substrate is preferably arranged so that the center point of the substrate is located upstream of the center point of the arcuate portion. Further, the total width (upstream width) of the upstream side wall and the arc-shaped corner in the direction perpendicular to the reaction gas flow direction is preferably larger than the width of the arc-shaped portion (downstream width).

  In this case, since the arcuate corners are formed instead of the sharp corners in the planar shape of the susceptor, the degree of heat radiation from the corners of the susceptor can be made smaller than when the sharp corners are formed. For this reason, the difference in temperature between the central portion of the susceptor and the outer peripheral portion such as the corner portion can be reduced (temperature uniformity in the susceptor can be improved).

  Further, by disposing the susceptor at an angle, the heat generation density due to induction heating in the vicinity of the upstream side wall of the susceptor is increased. If the substrate is shifted and arranged on the region side where the heat generation density is increased (in the direction of the upstream side wall portion), the temperature uniform region of the susceptor due to the presence of the portion where the heat generation density is increased as described above. It can be used effectively. As a result, the substrate temperature can be made uniform. Further, if the arc-shaped portion as described above is formed, the heat radiation characteristics on the downstream side of the susceptor can be made more uniform in the direction perpendicular to the central axis (the width direction of the susceptor).

  Further, since the upstream width of the susceptor is larger than the downstream width, a turbulent flow is generated in the reaction gas flow in the region facing the side wall of the susceptor. As a result, since the reaction gas diffuses in the width direction (relative to the flow) on the downstream side of the susceptor, sufficient reaction gas can be supplied onto the substrate located on the downstream side of the susceptor. For this reason, a film can be formed at a sufficient film formation speed even on a substrate located on the downstream side.

  The distance from the center of the substrate to the upstream side wall of the susceptor may be greater than the distance from the center of the substrate to the arcuate portion of the susceptor. In this case, the reaction gas flowing to the substrate can be sufficiently heated by the heat radiation from the susceptor located on the upstream side of the substrate. As a result, the deposition rate on the substrate can be sufficiently increased.

  The vapor deposition method according to the present invention is centered on a central axis that forms a processing vessel, a susceptor for holding the substrate, and a magnetic field for induction heating the susceptor, which is disposed inside the processing vessel. A gas phase film forming method using a gas phase film forming apparatus including a coil having a winding shape, and includes a susceptor arranging step and a film forming step. In the susceptor arranging step, the susceptor is arranged inside the processing container so that the extending direction of the surface holding the substrate in the susceptor intersects the extending direction of the central axis of the coil. In the step of forming the film, the film is formed on the substrate surface in a state where the susceptor is inductively heated by supplying electric power to the coil.

  In this case, if the extending direction of the surface holding the substrate in the susceptor intersects the extending direction of the central axis of the coil (that is, the susceptor is inclined with respect to the central axis of the coil), the heat generation density due to induction heating in the susceptor The distribution of changes. For this reason, the balance between heat generation and heat dissipation in the susceptor can be optimized by changing the angle θ formed by the direction in which the surface holding the substrate in the susceptor extends with respect to the direction in which the central axis of the coil extends. As a result, the temperature distribution of the substrate mounted on the susceptor (particularly the temperature distribution in the direction in which the central axis of the coil extends) can be made uniform. Therefore, film forming conditions (for example, film forming speed) on the substrate can be made uniform.

  In addition, when the process conditions for film formation (for example, the flow rate of the reaction gas) change, the heat dissipation conditions from the susceptor also change. In this case as well, by adjusting the angle θ appropriately, Temperature uniformity (ie, temperature uniformity at the substrate) can be optimized.

  A susceptor according to the present invention is a plate-shaped susceptor used in a vapor deposition apparatus for holding a substrate having a circular planar shape, and the planar shape of the susceptor is a linear one wall. , Arcuate corners connected to both ends of the one wall part, arcuate parts located on the opposite side of the one wall part, arcuate corners connected to both ends of the arcuate part and both ends of the one wall part And a side wall portion connecting the two. The substrate is arranged so that the center point of the substrate is located on the one wall side from the center point of the arc-shaped portion.

  In this case, since the arcuate corners are formed instead of the sharp corners in the planar shape of the susceptor, the degree of heat radiation from the corners of the susceptor can be made smaller than when the sharp corners are formed. For this reason, the temperature difference between the central portion of the susceptor and the outer peripheral portion such as a corner portion can be reduced.

  In addition, when a coil that forms a magnetic field for induction heating of a susceptor is used in a vapor deposition apparatus, if the susceptor is inclined with respect to the central axis of the coil, induction heating near one wall of the susceptor is performed. The heat generation density by increases. And if the substrate is shifted and arranged on the side of the region where the heat generation density is increased (one wall direction), the temperature uniform region of the susceptor due to the presence of the portion where the heat generation density is increased as described above. It can be used effectively. As a result, the substrate temperature can be made uniform. In addition, if the arc-shaped portion as described above is formed, the heat dissipation characteristics on the arc-shaped portion side of the susceptor can be made more uniform in the width direction of the susceptor (one direction parallel to the wall portion).

  A susceptor according to the present invention is a plate-like susceptor used in a vapor deposition apparatus for holding a substrate, and the vapor deposition apparatus forms a magnetic field used for induction heating of the susceptor. Therefore, a coil having a winding shape around the central axis is provided. The susceptor has a square shape based on the temperature distribution of the substrate when the planar shape of the susceptor is square and the substrate is held at the center of the square and the extending direction of the surface holding the substrate in the susceptor is parallel to the central axis. The shape of the susceptor and the arrangement of the substrate on the surface of the susceptor are made uniform so that the temperature distribution of the substrate is uniform when used in a state where the extending direction of the surface holding the substrate in the susceptor intersects the axis. It has been decided.

  In this case, the temperature distribution on the substrate disposed on the susceptor can be made more uniform than when a simple square susceptor is used. Here, the uniform temperature distribution means that the temperature at a plurality of locations on the substrate surface in a state where the susceptor is inductively heated is measured, and the variation in temperature data at the plurality of locations is small. Specifically, the case where the standard deviation of the temperature data at a plurality of locations is small, or the case where the maximum value among the differences of the respective temperature data with respect to the average value of the temperature data is small is applicable.

  In the susceptor, the susceptor may be plate-shaped, and the planar shape of the substrate may be circular. The planar shape of the susceptor consists of a straight one wall, an arc corner connected to both ends of the one wall, an arc portion located on the opposite side of the one wall, and both ends of the arc portion. You may consist of the side wall part which connects the circular-arc-shaped corner | angular part connected to the both ends of a wall part, respectively. The arrangement of the substrates may be determined such that the center point of the substrate is located on the one wall side from the center point of the arcuate portion.

  In this case, since the arcuate corners are formed instead of the sharp corners in the planar shape of the susceptor, the degree of heat radiation from the corners of the susceptor can be made smaller than when the sharp corners are formed. For this reason, the temperature difference between the central portion of the susceptor and the outer peripheral portion such as a corner portion can be reduced.

  In addition, if the susceptor is inclined with respect to the central axis of the coil, the heat generation density by induction heating in the vicinity of one wall portion of the susceptor increases. And if the substrate is shifted and arranged on the side of the region where the heat generation density is increased (one wall direction), the temperature uniform region of the susceptor due to the presence of the portion where the heat generation density is increased as described above. It can be used effectively. As a result, the substrate temperature can be made uniform.

  In addition, if the arc-shaped portion as described above is formed, the heat dissipation characteristics on the arc-shaped portion side of the susceptor can be made more uniform in the width direction of the susceptor (one direction parallel to the wall portion).

  In the susceptor, the total width (one side width) of the one wall portion and the arc-shaped corner portion in the direction (width direction) perpendicular to the direction from the one wall portion toward the arc-shaped portion is the width of the arc-shaped portion. It is preferable that it is larger than (the other side width). In this case, since the width of one side of the susceptor is larger than the width of the other side, when the reaction gas flows from the one wall side (upstream side) to the arcuate part side (downstream side) with respect to the susceptor, the side wall portion of the susceptor A turbulent flow is generated in the reaction gas flow in the region facing the surface. As a result, since the reaction gas diffuses in the width direction (relative to the flow) on the downstream side of the susceptor, sufficient reaction gas can be supplied onto the substrate located on the downstream side of the susceptor. For this reason, a film can be formed at a sufficient film formation speed even on a substrate located on the downstream side.

  Further, the distance from the center of the substrate to the one wall portion of the susceptor may be larger than the distance from the center of the substrate to the arcuate portion of the susceptor. In this case, the reaction gas flowing to the substrate can be sufficiently heated by heat radiation from the susceptor located on the upstream side of the substrate. As a result, the deposition rate on the substrate can be sufficiently increased.

  The susceptor may include a base material and a coating material formed to cover the surface of the base material. In this case, by disposing the coating material on the surface of the base material, it is possible to reduce the possibility that the base material is damaged by an external atmospheric gas or the like. As a coating material, it is possible to protect the base material, and to prevent diffusion of impurities during the film formation process, so that it can withstand a high temperature in the film formation process, as well as a material having resistance to the atmosphere of the film formation process. A heat-resistant material (for example, a material having a melting point of 1500 ° C. or higher), and an electric conductivity lower than that of the base material so that eddy current does not flow through the base material when induction heating is performed. A material, a paramagnetic material (for example, a material having a relative permeability of about 1 (for example, 0.5 or more and 1.5 or less)), or the like can be used. The material of the coating material is preferably selected as appropriate for each film forming process condition. From the viewpoint of improving the thermal uniformity of the susceptor, it is preferable to use a material having high thermal conductivity as the coating material. Note that the above-mentioned conditions regarding the electrical conductivity and magnetic properties are that the penetration depth of the magnetic field is inversely proportional to the root of the product of frequency, relative permeability, and vacuum permeability, so heat generation is concentrated on the coating material. Is to avoid.

  The coating material preferably includes at least one selected from the group consisting of a silicon carbide film, a tantalum carbide film, and a pyrolytic carbon film. In this case, it is possible to realize a coating material capable of protecting the base material as described above, preventing diffusion of impurities, and improving the thermal uniformity of the susceptor.

  The vapor phase film forming method according to the present invention includes a susceptor arranging step and a film forming step. In the susceptor arrangement step, the substrate is mounted on the susceptor according to the present invention, and the susceptor is arranged inside the processing container of the vapor deposition apparatus. In the step of forming the film, the film is formed on the substrate surface by supplying a reaction gas into the processing container while heating the susceptor by induction heating. In the process of forming the film, the susceptor is induction-heated using a coil that is wound around a central axis. In the susceptor arranging step, the susceptor is arranged so that the extending direction of the surface holding the substrate in the susceptor intersects the extending direction of the central axis of the coil.

  In this way, the temperature distribution of the substrate disposed on the susceptor disposed to be inclined with respect to the central axis of the coil is compared with the case where the square susceptor is disposed in parallel with the central axis as in the prior art. It can be made uniform. Therefore, a uniform film formation process can be performed on the substrate (for example, variation in film formation speed on the substrate can be reduced).

In the susceptor arrangement step of the vapor phase film forming apparatus or the vapor phase film forming method, the angle θ formed by the extending direction of the surface of the susceptor with respect to the extending direction of the central axis of the coil is:
| Θ | <atan (√ (H (W + H) / (L (W + L))))
May be set so as to satisfy the relational expression. In the susceptor, the length in the direction in which the central axis of the coil extends is L, the height in the direction intersecting the direction in which the central axis of the coil extends is H, and the direction in which the central axis of the coil extends and the direction of the height H The width of the susceptor in the direction perpendicular to the defined plane is W.

  If the above condition of the angle θ is satisfied, excessive heat generation at the outer periphery of the susceptor due to excessive tilting of the susceptor with respect to the central axis can be prevented. As a result, it is possible to suppress the temperature distribution at the susceptor from becoming nonuniform, that is, the temperature distribution at the substrate from becoming nonuniform.

  According to the present invention, even if the process conditions of the film formation process change, the temperature distribution of the substrate can be made uniform by changing the crossing angle (tilt angle) of the susceptor with respect to the central axis of the coil. Can be planned. As a result, even when the process conditions change, the film forming conditions on the substrate can be made uniform.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

  FIG. 1 is a schematic cross-sectional view showing a processing section of a vapor phase growth apparatus according to the present invention. FIG. 2 is a block diagram showing the configuration of the vapor phase growth apparatus according to the present invention including the processing section shown in FIG. FIG. 3 is a schematic plan view showing a susceptor according to the present invention used in the vapor phase growth apparatus shown in FIG. FIG. 4 is a schematic cross-sectional view taken along line IV-IV shown in FIG. A vapor phase growth apparatus and a susceptor according to the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the processing unit 3 of the vapor phase growth apparatus according to the present invention has a processing container 2 and a winding shape around a central axis, which is disposed so as to surround the outer periphery of the processing container 2. A high-frequency coil 4 as a coil, a susceptor 10 disposed inside the processing container 2, and an inclination angle of the susceptor 10 with respect to the direction of the coil axis (center axis) of the high-frequency coil 4 (direction indicated by an arrow 13) and a gantry 11 for holding in a state inclined by θ1. Here, the inclination angle θ1 is an angle formed between the direction of the coil axis (the direction indicated by the arrow 13) as the center axis of the coil and the upper surface holding the substrate 12 in the susceptor 10, but the illustrated susceptor Since the top surface and the bottom wall are parallel to each other, the inclination angle θ1 is shown as an angle formed by the direction of the coil axis indicated by the arrow 13 and the bottom wall.

  On the upper surface of the susceptor 10, a recess 18 (see FIG. 4) for holding the substrate 12 having a circular planar shape is formed. The gantry 11 is made of quartz, and includes a bottom wall 22, a front portion that is connected to the bottom wall and forms a convex portion 23, and a coil axis direction that is continuous with the convex portion 23 and indicated by an arrow 13 (a direction in which the bottom wall 22 extends). The upper wall 21 is inclined with respect to the angle θ1. The susceptor 10 is disposed on the upper wall 21. A predetermined reaction gas is supplied into the processing container 2 from the direction indicated by the arrow 15. The reaction gas flows in the direction indicated by the arrow 15 inside the processing container 2.

  As shown in FIG. 2, the vapor phase growth apparatus 1 including the processing unit 3 illustrated in FIG. 1 includes a processing unit 3 and a gas supply unit as a reactive gas supply member for supplying a reactive gas to the processing unit 3. 5, a gas discharge unit 6 for discharging gas from the processing unit 3, a power supply unit 7 for supplying predetermined power to the high-frequency coil 4 constituting the processing unit 3, a gas supply unit 5, and a gas discharge unit 6 and a control unit 8 for controlling the power supply unit 7. Note that the configuration of the vapor phase growth apparatus 1 is not limited to the configuration shown in FIG. 2, and other configurations are adopted as long as it is possible to form a film on the surface of the substrate 12 in the processing unit 3. May be.

  Next, the susceptor according to the present invention used in the vapor phase growth apparatus shown in FIGS. 1 and 2 will be described with reference to FIGS.

  As shown in FIGS. 3 and 4, the planar shape of the susceptor 10 according to the present invention is asymmetrical between the upstream side and the downstream side in the direction of the reaction gas flow indicated by the arrow 15. Regarding the susceptor 10, when the planar shape of the susceptor 10 is a square, the substrate 12 is held in the center of the square, and the extending direction of the surface holding the substrate 12 in the susceptor 10 is parallel to the coil axis indicated by the arrow 13. The temperature distribution of the substrate 12 in the case where the coil 12 is used in a state in which the extending direction of the upper surface holding the substrate 12 in the susceptor 10 intersects (inclines) with respect to the coil axis. Further, the shape of the susceptor 10 and the arrangement of the substrate 12 on the upper surface of the susceptor 10 are determined.

  Specifically, an upstream side wall portion 25 having a linear shape with a width D as one wall portion is located at a position away from the center 30 of the substrate 12 by a distance W on the upstream side in the gas flow direction indicated by the arrow 15. Is formed. Further, on both sides of the linear upstream side wall portion 25, arc-shaped corner portions 26 having a radius R2 are formed. Further, on the downstream side in the flow direction of the reaction gas indicated by the arrow 15 of the susceptor 10, a semicircular arc-shaped portion 27 having a radius R3 centering on a position 31 that is separated from the center 30 of the substrate 12 by δ downstream. Is formed. The end of the arcuate portion 27 on the downstream side and the arcuate corner portion 26 having a radius R2 on the upstream side in the flow direction of the reaction gas are connected to each other by a linear side wall portion 28. The substrate 12 is disposed on the susceptor 10 such that the center 30 that is the center point of the substrate 12 is located upstream of the position 31 that is the center point of the arc-shaped portion 27. As can be seen from FIG. 3, the width W1 of the upstream side wall portion 25 and the arc-shaped corner portion 26 is larger than the width W2 of the arc-shaped portion 27 having the radius R3 on the downstream side of the susceptor 10.

  In this case, since the arc-shaped corner portion 26 is formed in the planar shape of the susceptor 10 instead of the sharp corner portion, the degree of heat radiation from the corner portion 26 of the susceptor 10 is less than when the sharp corner portion is formed. Can be small. For this reason, the temperature difference between the central portion of the susceptor 10 and the outer peripheral portion such as the corner portion 26 can be reduced. Further, by disposing the susceptor 10 with an inclination angle θ1 with respect to the coil axis indicated by the arrow 13, the heat generation density by induction heating in the vicinity of the upstream side wall portion 25 of the susceptor 10 is increased. If the substrate 12 is shifted and arranged on the upstream side wall portion 25 side where the heat generation density is increased, the temperature uniform region of the susceptor 10 due to the presence of the portion where the heat generation density is increased as described above can be effectively used. Available. As a result, the temperature of the substrate 12 can be made uniform.

  In addition, if the arc-shaped portion 27 as described above is formed, the heat radiation characteristics on the downstream side of the susceptor 10 can be made more uniform in the width direction of the susceptor 10 (horizontal direction perpendicular to the arrow 13). . Further, since the width W1 that is the upstream width of the susceptor 10 is larger than the width W2 that is the downstream width, a turbulent flow is generated in the flow of the reaction gas in the region facing the side wall 28 of the susceptor 10. As a result, since the reaction gas diffuses in the width direction of the susceptor 10 on the downstream side of the susceptor 10, sufficient reaction gas can be supplied onto the substrate 12 located on the downstream side of the susceptor 10. For this reason, a film can be formed at a sufficient film formation speed even on the substrate 12 located on the downstream side.

  Further, the distance W from the center 30 of the substrate 12 to the upstream side wall portion 25 of the susceptor 10 is larger than the distance R3 from the center 30 of the substrate 12 to the arcuate portion 27 of the susceptor 10. Thus, in the susceptor 10, when the upstream width in the flow direction of the reaction gas is larger than the downstream width, the heat flows from the surface of the susceptor 10 located upstream of the substrate 12 to flow to the substrate 12. The incoming reaction gas can be heated sufficiently. As a result, the film formation rate on the substrate 12 can be sufficiently increased. Note that the planar shape of the susceptor 10 according to the present invention is not limited to the shape as shown in FIG. 3, and may be other shapes as long as the temperature condition of the substrate 12 can be made uniform. It can also be changed as appropriate.

  Further, as shown in FIG. 4, the susceptor 10 has a structure in which a coating material 17 is coated on the surface of a base material 16. An example of the material constituting the base material 16 is carbon. Examples of the material of the coating material 17 include silicon carbide (SiC), tantalum carbide (TaC), and pyrolytic carbon coating (for example, PYROGRAPH (registered trademark) manufactured by Toyo Tanso Co., Ltd.).

  In a horizontal cold wall type vapor phase growth apparatus (for example, an epitaxial growth apparatus) as shown in FIG. 1, a susceptor 10 as shown in FIGS. 3 and 4 is used, and the susceptor 10 is an arrow in the coil axis direction. The reason why the angle θ1 is inclined with respect to the direction shown in FIG. 13 is based on the following concept. That is, the temperature of the outer peripheral portion of the susceptor 10 is likely to decrease due to heat dissipation. Therefore, the temperature of the susceptor 10 is increased by inclining the susceptor 10 with respect to the coil axis direction indicated by the arrow 13 to increase the heat generation density in the outer peripheral portion where the temperature tends to decrease, that is, the end regions 14a and 14b in FIG. To equalize. In addition, since a region having a relatively uniform temperature on the susceptor 10 is formed from the center of the susceptor 10 to the high heat generation density portion (end region 14a), the substrate 12 is disposed near the region. Specifically, the center 30 of the substrate 12 is arranged at a position shifted by δ upstream from the position 31 that is the center of the arcuate portion.

  Further, the corner portion where heat dissipation is likely to occur and the rate of change in temperature is large is circular as shown in FIG. As a result, the degree of heat dissipation in the corner portion can be reduced, and as a result, the temperature distribution in the susceptor 10 can be made more uniform.

  Further, when the heat dissipation characteristics of the susceptor 10 change due to changes in the flow state of the reaction gas (for example, the flow rate or flow rate of the reaction gas), the susceptor 10 is changed by changing the inclination angle θ1 with respect to the coil axis of the susceptor 10. The balance between heat dissipation and heat generation can be adjusted. As a result, even when the flow state of the reaction gas is changed, the temperature uniformity of the substrate disposed on the susceptor 10 can be maintained.

Further, the coating material 17 constituting the susceptor 10 shown in FIG. 4 is required to have characteristics that protect the base material 16 and prevent diffusion of impurities into the base material 16. Specifically, the coating material 17 is heat resistant (for example, has a melting point of 1500 ° C. or higher), has a lower electrical conductivity than the carbon constituting the base material 16, and is a paramagnetic material. It is preferable that the non-permeability is approximately 1 (specifically, for example, 0.5 to 1.5, more preferably 0.7 to 1.2). As described above, the electrical conductivity and magnetism are requested as shown in the following Equation 1. The penetration depth δ of the magnetic field is the frequency f, the non-permeability μ, the vacuum permeability μ ₀ , and the electrical conductivity. This is to prevent heat generation from concentrating on the coating material 17 because it is inversely proportional to the root of the product of σ.

  Further, from the viewpoint of improving the thermal uniformity of the susceptor 10 as the material of the coating material 17, it is preferable to use a substance having a high thermal conductivity. As a result of studying the constraint conditions described above, it is conceivable that the above-described silicon carbide, tantalum carbide, or the like is used as the material constituting the coating material 17.

  In the vapor phase growth apparatus according to the present invention shown in FIGS. 1 and 2, the tilt angle of the susceptor 10 with respect to the coil axis indicated by the arrow 13 can be arbitrarily changed by replacing the gantry 11. Specifically, as shown in FIG. 5, the gantry 11 is prepared such that the inclination angle θ2 of the upper wall 21 with respect to the arrow 13 is different from the inclination angle θ1 of the gantry 11 shown in FIG. And you may prepare the other mount from which this inclination angle differs further. Then, the gantry 11 is selected from a plurality of gantry and arranged inside the processing container 2 so that the inclination angle of the susceptor 10 becomes a predetermined angle. Then, the susceptor 10 is arranged on the mount 11. In this way, the inclination angle of the susceptor 10 with respect to the coil axis (the direction indicated by the arrow 13) can be arbitrarily changed. FIG. 5 is a schematic cross-sectional view showing another example of the gantry 11 used in the vapor phase growth apparatus according to the present invention.

  Next, a vapor phase growth method using the vapor phase growth apparatus according to the present invention shown in FIG. 1 will be described. FIG. 6 is a flowchart showing a vapor phase growth method according to the present invention. The vapor phase growth method according to the present invention will be described with reference to FIG.

  As shown in FIG. 6, in the vapor phase growth method according to the present invention, first, a step (S10) of placing a gantry in the apparatus is performed. Specifically, the gantry 11 for arranging the susceptor 10 is arranged inside the processing container 2 constituting the processing unit 3 of the vapor phase growth apparatus. At this time, by selecting one of the gantry 11 from a plurality of gantry having different inclination angles, the susceptor inclination angle (coil axis and upper part of the susceptor 10) with respect to a coil axis (direction shown by an arrow 13) described later is selected. The angle at which the direction of the surface intersects can be changed.

  Next, a step (S20) of placing a susceptor on a gantry as a susceptor placement step is performed. Specifically, the susceptor 10 is mounted on the upper wall 21 of the gantry 11 disposed inside the processing container 2 as shown in FIG. The susceptor 10 is in a state where a substrate 12 that is an object of film formation is already disposed. Next, a film forming step (S30) as a step of forming a film is performed. Specifically, after setting the pressure inside the processing container 2 to a predetermined pressure value, a predetermined reaction gas is supplied from the gas supply unit 5 (see FIG. 2) into the processing container 2. The reaction gas flows in the direction indicated by the arrow 15 in FIG. At the same time, a magnetic field is formed inside the processing container 2 by supplying electric power to the high-frequency coil 4 from the power supply unit 7 (see FIG. 2). The temperature of the susceptor 10 is raised by induction overheating using this magnetic field. In this way, a predetermined film can be formed on the surface of the substrate 12. In this case, the substrate 12 disposed on the susceptor 10 disposed to be inclined with respect to the coil axis of the high-frequency coil 4 is compared with the case where the square susceptor is disposed in parallel with the coil axis as in the prior art. The temperature distribution can be made uniform. Therefore, a uniform film forming process can be performed on the substrate 12.

  Further, since the susceptor 10 is inclined with respect to the direction of the coil axis (the direction indicated by the arrow 13), the heat generation condition in the susceptor can be changed by changing the inclination angle.

  When the susceptor 10 is tilted so as to intersect the coil axis indicated by the arrow 13, the upstream side (relative to the flow of the reaction gas) of the susceptor 10 is lower than the downstream side as shown in FIG. In addition to inclining the susceptor in a direction such that the susceptor 10 is in a tilted state, as shown in FIG. 7, the susceptor 10 may be tilted in a direction in which the upstream side of the susceptor 10 is raised from the downstream side. FIG. 7 is a schematic sectional view showing a modification of the vapor phase growth apparatus according to the present invention. A modification of the vapor phase growth apparatus according to the present invention will be described with reference to FIG.

  The processing unit of the vapor phase growth apparatus shown in FIG. 7 basically has the same structure as the processing unit of the vapor phase growth apparatus shown in FIG. 1, but the arrangement of the gantry 35 and the arrow 13 of the susceptor 10 are shown. The inclination angle with respect to the direction of the coil axis is different. That is, in the vapor phase growth apparatus shown in FIG. 7, unlike the vapor phase growth apparatus shown in FIG. 1, the protruding portion 23 of the gantry 35 has a reaction gas flow indicated by the arrow 15 rather than the susceptor 10. It is arranged to come downstream. As a result, the susceptor 10 is in a state where the upstream end in the flow of the reaction gas is higher than the downstream end. The inclination angle θ3 at this time is defined by the angle θ3 formed by the bottom wall of the susceptor 10 with respect to the arrow 13 indicating the coil axis. 7 is arranged downstream of the susceptor 10 with respect to the flow of the reaction gas, for example, when the flow of the reaction gas is slow or when the reaction heat generated in the film forming process is large. This is effective in the case where the temperature around the susceptor 10 becomes high and the heat dissipation efficiency from the downstream side of the susceptor 10 to the outside is consequently reduced.

  Next, a method of determining the inclination angle θ with respect to the coil axis of the susceptor 10 will be described with reference to FIGS. FIG. 8 is a schematic cross-sectional view for explaining the arrangement of the susceptor according to the present invention. FIG. 9 is a schematic plan view of the susceptor viewed from the direction indicated by the arrow 24 in FIG.

  As shown in FIGS. 8 and 9, a plate-like susceptor 10 having a square shape of a length L, a height H, and a width W in a direction indicated by an arrow 13 that is a coil axis direction is considered. The upper wall of the susceptor 10 is E, the bottom wall is F, the side wall on the upstream side of the reaction gas flow in the susceptor 10 is A, the side wall on the downstream side is C, and the side wall on the right side when viewed from the upstream side of the reaction gas flow is B , D on the left side wall. At this time, as shown in FIG. 8, when the inclination angle of the bottom wall F of the susceptor 10 with respect to the direction of the coil axis indicated by the arrow 13 is θ, the upstream side susceptor 10 in the flow of the reaction gas indicated by the arrow 15. The lower end on the downstream side of the susceptor 10 is moved away from the arrow 13 by L × sin θ. Further, the distance from the upper end of the upstream side wall A to the arrow 13 in the flow of the reaction gas is expressed as H × cos θ.

  Here, the upper limit of the tilt angle θ is first considered. If the susceptor 10 is tilted too much with respect to the direction indicated by the arrow 13 (θ is too large), the loop surface of the current flowing through the susceptor 10 due to the magnetic field provided by the high-frequency coil 4 (see FIG. 1) The path of the upper wall E-side wall D-bottom wall F-side wall B is changed to the side wall A-side wall B-side wall C-side wall D. As a result, heat generation due to the induced current is excessively concentrated on the outer peripheral portion of the susceptor 10. For this reason, the uniformity of temperature in the susceptor 10 deteriorates. Therefore, Q1 is the amount of heat generated by the susceptor 10 when a magnetic flux is applied so that the current loop of the above-mentioned top wall E-side wall D-bottom wall F-side wall B is generated, and side wall A-side wall B-side wall C. -When the heat generation amount of the susceptor 10 when the magnetic flux is applied so as to generate a current loop of the path of the side wall D is Q2, the heat generation amount Q1 exceeds the heat generation amount Q2 (satisfying the condition of Q1 / Q2> 1) Was considered as a constraint on the tilt angle θ. Here, the calorific value Q1 and the calorific value Q2 are expressed as shown in Equations 2 and 3 below.

Here, δ represents the penetration depth of the magnetic field, and σ represents the electrical conductivity of the susceptor. When the inclination angle θ is maximum (when it is θ _max ), the heat generation amount Q1 = the heat generation amount Q2. For this reason, from Equation 2 and Equation 3 described above, the maximum value θ _max of the tilt angle satisfies the following Equation 4.

  Next, the lower limit of the tilt angle θ will be examined. Here, the case where the inclination angle θ is negative, that is, the case where the downstream side of the susceptor 10 is lower than the upstream side as shown in FIG. 7 is also considered.

  Normally, at the inclination angle θ = 0 °, the amount of heat released is larger than the amount of heat generated at the downstream end in the reaction gas flow direction as compared to the center of the susceptor 10. For this reason, it seems that the optimum value exists in the range of the inclination angle θ> 0 ° which is a direction for correcting such a state. On the other hand, when the flow of the reaction gas is slow, or when the amount of reaction heat is large, the outside air temperature increases on the downstream side of the susceptor 10. As a result, heat dissipation on the downstream side of the susceptor 10 is deteriorated. Therefore, it is necessary to correct the direction opposite to that described above, that is, to set the tilt angle θ in the range of the tilt angle θ <0 °. The lower limit value of the inclination angle θ in the minus direction is equal to the value obtained by inverting the sign of the inclination angle θ of the upper limit value described above.

  As a result, it is considered that the range of the inclination angle θ is a range represented by the following formula 5.

  If the range of the inclination angle θ is set to a range such as Equation 5, excessive heat generation at the outer peripheral portion of the susceptor 10 due to excessive inclination of the susceptor 10 with respect to the coil axis can be prevented. As a result, it is possible to suppress the temperature distribution at the susceptor 10 from becoming nonuniform, that is, the temperature distribution at the substrate 12 from becoming nonuniform.

  For example, when a rectangular parallelepiped susceptor having a height H = 20 mm and a length L = width W = 80 mm is considered, the absolute value of the inclination angle θ is less than 21.6 ° from the above equation 5 (the range of the inclination angle θ is −21). .6 ° and less than 21.6 °).

  The results of specific studies by the inventor on the parameters of the susceptor according to the present invention shown in FIGS. 3 and 4 are shown below. That is, as a specific example of the dimensions of the susceptor 10, when the radius of the substrate 12 is R1, the parameters for specifying the shape shown in FIGS. 3 and 4 can be set as follows. Specifically, R3 = 1.48 × R1, R2 = 0.78 × R1, D = 1.56 × R1, δ = 0.20 × R1, W = 0.98 × R1, H = 0.78. It can be set to xR1. As for the material constituting the susceptor 10, the magnetic permeability and electrical conductivity using the above-described formula 1 are set so that the above-described height H becomes H = 2 × δ with respect to the penetration depth δ of the magnetic field. And determining the frequency. When the heat dissipation characteristics from each surface are substantially uniform with respect to the susceptor under such conditions, the inclination angle θ may be set to 10 °. On the other hand, when the flow of the reaction gas is slow, the heat radiation characteristics from the susceptor 10 are lowered toward the downstream side in the flow of the reaction gas. In this case, it is necessary to change the inclination angle θ in a range of 0 ° to 10 ° so as to adapt to the flow rate of the reaction gas.

  Next, the susceptor 10 according to the present invention shown in Example 1 was vapor-grown on the substrate 12 in a state where the susceptor 10 according to the present invention was inclined by the inclination angle θ1 = 5 ° with respect to the coil axis direction as shown in FIG. The growth rate of the film was compared between the case and the case where the film was grown on the surface of the substrate 12 using the vapor phase growth apparatus as a comparative example shown in FIGS. This will be specifically described below. FIG. 10 is a schematic cross-sectional view showing a processing unit of a vapor phase growth apparatus used as a comparative example. FIG. 10 corresponds to FIG. FIG. 11 is a schematic plan view showing a susceptor as a comparative example used in the vapor phase growth apparatus shown in FIG. FIG. 11 is a schematic plan view of the susceptor 40 viewed from the direction indicated by the arrow 41 in FIG. The susceptor 40 used as a comparative example has a square planar shape with a width W0 and a length L0 of 3.1 × R1. The height H0 of the susceptor 40 is 0.78 × R1, which is the same as the thickness H of the susceptor according to the present invention. The substrate 12 is arranged in the center of such a susceptor 40.

On the other hand, in the vapor phase growth apparatus as an example of the present invention, the susceptor 10 shown in Example 1 was disposed in the processing vessel with an inclination angle θ = 5 °. And in each vapor phase growth apparatus, the film-forming process was performed on the same conditions. Specifically, the radius R1 of the substrate is 25.4 mm, silane (SiH ₄ ) and propane (C ₃ H ₈ ) are used as the reaction gas, the frequency of the current applied to the high frequency coil 4 is 110 kHz, and the flow rate of the reaction gas. Was 0.03% silane and 0.04% propane in volume ratio to the carrier gas. And the growth rate of the film | membrane in the surface of the board | substrate 12 which performed such a film-forming process was measured. As a measurement method, a method of measuring a change in the thickness of the wafer after film formation and dividing by the film formation time was used. The result is shown in FIG.

  FIG. 12 is a graph showing experimental results in Example 2. In FIG. 12, the horizontal axis indicates the position on the substrate, and the vertical axis indicates the film growth rate. The growth rate on the vertical axis is shown as a relative value with the average growth rate of the entire measured value as 100% and the average value as a reference. As for the position on the horizontal axis, the upstream end of the substrate in the direction in which the reaction gas flows is 100%, the downstream end is 0%, and the position between them is shown as a relative value.

  As can be seen from FIG. 12, the growth rate of the film in the comparative example becomes higher toward the upstream side, and the variation of the value is relatively large. On the other hand, in the example of the present invention, it can be seen that the growth rate of the film is more uniform (the variation is smaller) than the growth rate distribution of the comparative example.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is shown not by the embodiments and examples described above but by the scope of claims for patent, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims for patent.

It is a cross-sectional schematic diagram which shows the process part of the vapor phase growth apparatus by this invention. It is a block diagram which shows the structure of the vapor phase growth apparatus by this invention containing the process part shown in FIG. It is a plane schematic diagram which shows the susceptor by this invention used in the vapor phase growth apparatus shown in FIG. It is a cross-sectional schematic diagram in line segment IV-IV shown in FIG. It is a cross-sectional schematic diagram which shows the other example of the mount frame 11 used in the vapor phase growth apparatus by this invention. It is a flowchart which shows the vapor phase growth method by this invention. It is a cross-sectional schematic diagram which shows the modification of the vapor phase growth apparatus by this invention. It is a cross-sectional schematic diagram for demonstrating arrangement | positioning of the susceptor by this invention. FIG. 9 is a schematic plan view of the susceptor viewed from the direction indicated by the arrow 24 in FIG. 8. It is a cross-sectional schematic diagram which shows the process part of the vapor phase growth apparatus used as a comparative example. It is a plane schematic diagram which shows the susceptor as a comparative example used in the vapor phase growth apparatus shown in FIG. 6 is a graph showing experimental results in Example 2.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Vapor growth apparatus, 2 processing container, 3 processing part, 4 high frequency coil, 5 gas supply part, 6 gas discharge part, 7 power supply part, 8 control part, 10,40 susceptor, 11,35 mount, 12 substrate, 13 , 15, 24, 41 Arrow, 14a, 14b End region, 16 base material, 17 coating material, 18 concave portion, 21 top wall, 22 bottom wall, 23 convex portion, 25 upstream side wall portion, 26 corner portion, 27 arc shape Part, 28 sidewalls, 30 center, 31 position.

Claims (12)

A processing vessel;
A susceptor disposed inside the processing vessel for holding a substrate;
A coil that forms a magnetic field for inductively heating the susceptor and is wound around a central axis;
A vapor deposition apparatus in which the extending direction of the surface holding the substrate in the susceptor intersects the extending direction of the central axis of the coil. In the susceptor, the length in the direction in which the central axis of the coil extends is L, the height in a direction intersecting the direction in which the central axis of the coil extends is H, the direction in which the central axis of the coil extends and the height H When the width in the direction perpendicular to the plane defined by the direction is W, the angle θ formed by the extending direction of the surface of the susceptor with respect to the extending direction of the central axis of the coil is
| Θ | <atan (√ (H (W + H) / (L (W + L))))
The vapor deposition apparatus according to claim 1, wherein the relational expression is satisfied. A reaction gas supply member for circulating the reaction gas inside the processing container;
The planar shape of the substrate is circular,
The planar shape of the susceptor is
An end located on the upstream side of the flow of the reaction gas flowing through the inside of the processing vessel, and a straight upstream side wall; and
Arc-shaped corners connected to both ends of the upstream side wall,
An arcuate portion that is an end located on the downstream side of the flow of the reaction gas;
It consists of side wall portions that connect both end portions of the arc-shaped portion and arc-shaped corner portions connected to both ends of the upstream side wall portion, respectively.
3. The vapor deposition apparatus according to claim 1, wherein the substrate is disposed such that a center point of the substrate is positioned upstream of a center point of the arc-shaped portion. The susceptor is
A substrate;
The vapor-phase film-forming apparatus of any one of Claims 1-3 containing the coating material formed so that the surface of the said base material might be covered.   The vapor deposition apparatus according to claim 4, wherein the coating material includes at least one selected from the group consisting of a silicon carbide film, a tantalum carbide film, and a pyrolytic carbon film. A processing container, a susceptor that is disposed inside the processing container and holds a substrate, and a coil that forms a magnetic field for induction heating of the susceptor and is wound around a central axis. A vapor deposition method using a vapor deposition apparatus,
A susceptor disposition step of disposing the susceptor inside the processing container such that the extending direction of the surface holding the substrate in the susceptor intersects the extending direction of the central axis of the coil;
Forming a film on the surface of the substrate in a state where the susceptor is inductively heated by supplying electric power to the coil. In the susceptor arranging step, an angle θ formed by a direction in which the surface of the susceptor extends with respect to a direction in which the central axis of the coil extends is defined as L in the direction in which the central axis of the coil extends in the susceptor, When the height in the direction intersecting the direction in which the central axis of the coil extends is H, and the width in the direction perpendicular to the plane defined by the direction in which the central axis of the coil extends and the direction of the height H is W,
| Θ | <atan (√ (H (W + H) / (L (W + L))))
The vapor phase film-forming method according to claim 6, wherein the following relational expression is satisfied. A plate-shaped susceptor for holding a substrate having a circular planar shape, which is used in a vapor deposition apparatus,
The planar shape of the susceptor is
A straight one wall,
Arcuate corners continuous to both ends of the one wall part;
An arcuate portion located opposite to the one wall portion;
It consists of side wall portions that respectively connect both end portions of the arc-shaped portion and arc-shaped corner portions that are connected to both ends of the one wall portion,
The susceptor, wherein the substrate is arranged such that a center point of the substrate is located closer to the one wall portion than a center point of the arcuate portion. A plate-shaped susceptor for holding a substrate used in a vapor deposition apparatus,
The vapor phase film forming apparatus includes a coil that is wound around a central axis for forming a magnetic field used for induction heating of the susceptor,
From the temperature distribution of the substrate when the planar shape of the susceptor is square and the substrate is held in the center of the square and the extending direction of the surface holding the substrate in the susceptor is parallel to the central axis, The shape of the susceptor and the surface of the susceptor are uniform so that the temperature distribution of the substrate becomes uniform when used in a state where the extending direction of the surface holding the substrate in the susceptor intersects the central axis. A susceptor in which the arrangement of the substrate is determined. The susceptor is plate-shaped,
The planar shape of the substrate is circular,
The planar shape of the susceptor is
A straight one wall,
Arcuate corners continuous to both ends of the one wall part;
An arcuate portion located opposite to the one wall portion;
It consists of side wall portions that respectively connect both end portions of the arc-shaped portion and arc-shaped corner portions that are connected to both ends of the one wall portion,
The susceptor according to claim 9, wherein the arrangement of the substrate is determined so that the center point of the substrate is located closer to the one wall portion than the center point of the arcuate portion. A substrate;
The susceptor of any one of Claims 8-10 containing the coating material formed so that the surface of the said base material might be covered. A susceptor disposition step of mounting a substrate on the susceptor according to any one of claims 8 to 11 and disposing the susceptor inside a processing container of a vapor deposition apparatus;
Forming a film on the substrate surface by supplying a reaction gas into the processing vessel while heating the susceptor by induction heating,
In the step of forming the film, the susceptor is induction-heated using a coil that is wound around a central axis,
In the susceptor arranging step, the susceptor is arranged such that the extending direction of the surface holding the substrate in the susceptor intersects the extending direction of the central axis of the coil.

Images