JP2021082824A - Vapor phase growth apparatus - Google Patents

Abstract

To provide a vapor phase growth apparatus capable of improving uniformity of temperatures of a substrate.SOLUTION: A vapor phase growth apparatus comprises: a reaction chamber; an annular holder which is provided in the reaction chamber and on which a substrate is loaded, the annular holder including an annular outer peripheral part 50 constituting an outer peripheral portion and an annular inner peripheral part 52 constituting an inner peripheral portion and having on an upper part thereof an annular protrusion 54 separated from the outer peripheral part, the outer peripheral part having a top surface provided above a top surface of the annular protrusion; and a heater provided below the annular holder. In a state in which part of an end of an outer peripheral region of the substrate W loaded on the annular holder is in contact with an inner peripheral surface E2 of the outer peripheral part, the whole region of the top surface of the annular protrusion comes into contact with a rear surface of the substrate. The annular holder has a recess 50c on the inner peripheral surface of the outer peripheral part. In the annular holder's radial cross section including the recess, an amount of inward protrusion of the inner peripheral surface of the outer peripheral part is maximized at the top surface of the outer peripheral part.SELECTED DRAWING: Figure 8

Description

The present invention relates to a vapor deposition apparatus that supplies a gas to form a film.

As a method for forming a high-quality semiconductor film, there is an epitaxial growth technique in which a single crystal film is grown by vapor phase growth on a substrate such as a wafer. In a vapor phase growth apparatus using an epitaxial growth technique, a wafer is placed on a support portion in a reaction chamber held at normal pressure or reduced pressure.

Then, while heating this wafer, a process gas such as a source gas, which is a raw material for film formation, is supplied from the upper part of the reaction chamber to the surface of the wafer in the reaction chamber. A thermal reaction of the source gas occurs on the wafer surface, and an epitaxial single crystal film is formed on the wafer surface.

The characteristics of the epitaxial single crystal film formed on the wafer surface depend on the temperature of the wafer. Therefore, it is desired to improve the temperature uniformity in the wafer surface.

Patent Document 1 describes a vapor phase growth apparatus in which a susceptor supporting a wafer is provided with a convex portion in order to reduce deformation of the wafer and uniformly heat the wafer.

Japanese Unexamined Patent Publication No. 7-58040

An object to be solved by the present invention is to provide a vapor phase growth apparatus capable of improving the temperature uniformity of a substrate.

The vapor phase growth apparatus of one aspect of the present invention is an annular holder provided in the reaction chamber and on which a substrate is placed, and constitutes an annular outer peripheral portion and an inner peripheral portion constituting the outer peripheral portion. An annular holder having an annular inner peripheral portion having an annular convex portion at an upper portion separated from the outer peripheral portion, and an annular holder having an upper surface of the outer peripheral portion above the upper surface of the annular convex portion, and an annular holder. The annular convex portion is provided with a heater provided below, and a part of the end portion of the outer peripheral region of the substrate placed on the annular holder is in contact with the inner peripheral surface of the outer peripheral portion. The entire upper surface of the annular holder is in contact with the back surface of the substrate, and the annular holder has a recess on the inner peripheral surface of the outer peripheral portion. The amount of protrusion inward of the surface is maximum on the upper surface of the outer peripheral portion.

In the vapor phase growth apparatus of the above aspect, it is desirable that the height of the annular convex portion is smaller than the width of the annular convex portion in the radial cross section of the annular holder.

In the vapor phase growth apparatus of the above aspect, it is desirable that the recess is provided on the entire circumference of the inner peripheral surface of the outer peripheral portion.

In the vapor phase growth apparatus of the above aspect, the annular holder has a plurality of island-shaped convex portions protruding inward of the outer peripheral portion and separated from the annular convex portion, and the concave portion is the island-shaped convex portion. It is desirable to be provided in.

In the vapor phase growth apparatus of the above aspect, it is desirable that the annular convex portion is provided at a predetermined distance from the inner circumference of the inner peripheral portion.

In the vapor phase growth apparatus of the above aspect, it is desirable that the upper surface of the annular convex portion is flat.

According to the present invention, it is possible to provide a vapor phase growth apparatus capable of improving the temperature uniformity of a substrate.

The schematic sectional view of the vapor phase growth apparatus of 1st Embodiment. The schematic diagram of the annular holder of 1st Embodiment. The explanatory view of the operation and effect of the vapor phase growth apparatus of 1st Embodiment. The explanatory view of the operation and effect of the vapor phase growth apparatus of 1st Embodiment. The explanatory view of the operation and effect of the vapor phase growth apparatus of 1st Embodiment. The explanatory view of the operation and effect of the vapor phase growth apparatus of 1st Embodiment. The explanatory view of the operation and effect of the vapor phase growth apparatus of 1st Embodiment. FIG. 3 is a schematic cross-sectional view of a part of the annular holder of the second embodiment. FIG. 3 is a schematic cross-sectional view of a part of the annular holder of the modified example of the second embodiment. The schematic diagram of the annular holder of the 3rd Embodiment. The explanatory view of the operation and effect of the gas phase growth apparatus of the 3rd embodiment. FIG. 3 is a schematic cross-sectional view of a part of the annular holder of the fourth embodiment. FIG. 3 is a schematic cross-sectional view of a part of the annular holder of the fifth embodiment.

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

In the present specification, the same or similar members may be designated by the same reference numerals.

In the present specification, the direction of gravity in a state where the vapor deposition apparatus is installed so that a film can be formed is defined as "downward", and the opposite direction is defined as "upper". Therefore, "lower" means the position in the direction of gravity with respect to the reference, and "downward" means the direction of gravity with respect to the reference. The "upper part" means a position in the direction opposite to the gravitational direction with respect to the reference, and the "upper" means the direction opposite to the gravitational direction with respect to the reference. The "vertical direction" is the direction of gravity.

Further, in the present specification, the “process gas” is a general term for gases used for film formation on a substrate, and is a concept including, for example, a source gas, a carrier gas, a diluent gas, and the like.

(First Embodiment)
The vapor phase growth apparatus of the present embodiment is a reaction chamber, an annular holder provided in the reaction chamber on which a substrate is placed, an annular outer peripheral portion forming an outer peripheral portion, and an outer peripheral portion forming an inner peripheral portion. An annular holder having an annular inner peripheral portion having an annular convex portion at an upper portion and an upper surface of an outer peripheral portion provided above the upper surface of the annular convex portion, and a heater provided below the annular holder. , Equipped with.

FIG. 1 is a schematic cross-sectional view of the vapor phase growth apparatus of the present embodiment. The vapor phase growth apparatus of the present embodiment is, for example, a single-wafer type epitaxial growth apparatus using a MOCVD method (metalorganic vapor phase growth method).

The vapor phase growth apparatus of the present embodiment includes a reaction chamber 10, a first gas supply path 11, a second gas supply path 12, and a third gas supply path 13. The reaction chamber 10 includes an annular holder 14, a rotating body unit 16, a rotating shaft 18, a rotating drive mechanism 20, a shower plate 22, an in-heater (heater) 24, an out-heater 26, a reflector 28, a support column 34, a fixing base 36, and a fixed shaft. 38, equipped with a gas discharge port 40.

The first gas supply path 11, the second gas supply path 12, and the third gas supply path 13 supply the process gas to the reaction chamber 10.

The first gas supply path 11 supplies, for example, the first process gas containing the organic metal of the Group III element and the carrier gas to the reaction chamber 10. The first process gas is a gas containing a group III element when a film of a group III-V semiconductor is formed on a wafer.

Group III elements are, for example, gallium (Ga), Al (aluminum), In (indium) and the like. Further, the organic metal is trimethylgallium (TMG), trimethylaluminum (TMA), trimethylindium (TMI) and the like.

The second gas supply path 12 supplies, for example, a second process gas containing _{ammonia (NH 3) to the reaction chamber 10.} The second process gas is a source gas of a group V element, nitrogen (N), when a film of a group III-V semiconductor is formed on a wafer.

The third gas supply path 13 supplies, for example, a diluting gas for diluting the first process gas and the second process gas to the reaction chamber 10. The concentration of the Group III element and the Group V element supplied to the reaction chamber 10 is adjusted by diluting the first process gas and the second process gas with the diluting gas. The diluting gas is, for example, an inert gas such as hydrogen gas, nitrogen gas, argon gas, or a mixed gas thereof.

The reaction chamber 10 is provided with, for example, a stainless steel cylindrical wall surface 17. The shower plate 22 is provided above the reaction chamber 10. The shower plate 22 is provided with a plurality of gas ejection holes. Process gas is supplied into the reaction chamber 10 from the plurality of gas ejection holes.

The annular holder 14 is provided inside the reaction chamber 10. A wafer (board) W can be placed on the annular holder 14. The annular holder 14 is provided with an opening at the center.

The annular holder 14 is formed of, for example, ceramics such as silicon carbide (SiC), tantalum carbide (TaC), boron nitride (BN), and pyrotechnic graphite (PG), or carbon as a base material. For the annular holder 14, for example, carbon coated with SiC, BN, TaC, PG, or the like can be used.

The annular holder 14 is fixed to the upper part of the rotating body unit 16. The rotating body unit 16 is fixed to the rotating shaft 18. The annular holder 14 is indirectly fixed to the rotating shaft 18.

The rotation shaft 18 can be rotated by the rotation drive mechanism 20. The rotation drive mechanism 20 makes it possible to rotate the annular holder 14 by rotating the rotation shaft. By rotating the annular holder 14, the wafer W placed on the annular holder 14 can be rotated.

For example, the wafer W is rotated at a rotation speed of 50 rpm or more and 3000 rpm or less. The rotation drive mechanism 20 is composed of, for example, a motor and a bearing.

The in-heater 24 and the out-heater 26 are provided below the annular holder 14. The in-heater 24 and the out-heater 26 are provided in the rotating body unit 16. The out heater 26 is provided between the in heater 24 and the annular holder 14.

The in-heater 24 and the out-heater 26 heat the wafer W held in the annular holder 14. The in-heater 24 heats at least the central portion of the wafer W. The out heater 26 heats the outer peripheral portion of the wafer W. The inheater 24 has, for example, a disk shape. The out heater 26 is, for example, an annular shape.

The reflector 28 is provided below the in-heater 24 and the out-heater 26. An in-heater 24 and an out-heater 26 are provided between the reflector 28 and the annular holder 14.

The reflector 28 reflects the heat radiated downward from the in-heater 24 and the out-heater 26 to improve the heating efficiency of the wafer W. Further, the reflector 28 prevents the members below the reflector 28 from being heated. The reflector 28 has, for example, a disk shape.

The reflector 28 is made of a material having high heat resistance. The reflector 28 has heat resistance to a temperature of 1100 ° C. or higher, for example.

The reflector 28 is formed using, for example, ceramics such as SiC, TaC, carbon, BN, and PG, or a metal such as tungsten as a base material. When ceramics are used for the reflector 28, a sintered body or a base material produced by vapor phase growth can be used. The reflector 28 may also be a carbon base material coated with ceramics such as SiC, TaC, BN, PG, and glassy carbon.

The reflector 28 is fixed to the fixing base 36 by, for example, a plurality of support columns 34. The fixed base 36 is supported by, for example, a fixed shaft 38.

A push-up pin (not shown) is provided in the rotating body unit 16 in order to attach and detach the wafer W from the annular holder 14. The push-up pin penetrates, for example, the reflector 28 and the inheater 24.

The gas discharge port 40 is provided at the bottom of the reaction chamber 10. The gas discharge port 40 discharges the surplus reaction product after the source gas reacts on the surface of the wafer W and the surplus process gas to the outside of the reaction chamber 10.

Further, a wafer inlet / outlet and a gate valve (not shown) are provided on the wall surface 17 of the reaction chamber 10. The wafer W can be carried in and out of the reaction chamber 10 by the wafer inlet / outlet and the gate valve.

FIG. 2 is a schematic view of the annular holder of the present embodiment. FIG. 2A is a top view, and FIG. 2B is a cross-sectional view taken along the line AA'of FIG. 2A.

The annular holder 14 has an outer peripheral portion 50 forming an outer peripheral portion and an inner peripheral portion 52 provided inside the outer peripheral portion 50. The outer peripheral portion 50 and the inner peripheral portion 52 are integrally molded, for example.

The outer peripheral portion 50 is annular.

The inner peripheral portion 52 is annular. The inner peripheral portion 52 is provided inside the outer peripheral portion 50. Hereinafter, the inner end portion (E2 in FIG. 2) of the outer peripheral portion 50 may be expressed as the inner peripheral surface E2 of the outer peripheral portion 50.

The inner peripheral portion 52 is a counterbore of the annular holder 14. The wafer W is held on the inner peripheral portion 52 and inside the outer peripheral portion 50.

An annular convex portion 54 is provided on the upper portion of the inner peripheral portion 52. The annular convex portion 54 is provided so as to be separated from the outer peripheral portion 50. In other words, the outer end of the annular convex 54 (E3 in FIG. 2B) is separated from the inner end of the outer peripheral 50 (E2 in FIG. 2B).

The upper surface of the convex portion 54 is below the upper surface 50a of the outer peripheral portion 50. The convex portion 54 is provided so that the inner end portion is flush with the inner end portion (E1 in FIG. 2B) of the inner peripheral portion 52. In other words, the position of the inner end of the convex portion 54 coincides with the position of the inner end of the inner peripheral portion 52.

As shown in FIG. 2B, in the radial cross section of the annular holder 14, the height of the annular convex portion 54 (h in FIG. 2B) is, for example, the width of the annular convex portion 54 ( It is smaller than d) in FIG. 2 (b). Since the height of the annular convex portion 54 is smaller than the width, the mechanical strength of the annular convex portion 54 is increased.

The upper end corner of the annular convex portion 54 is chamfered, for example. By chamfering, chipping of the annular convex portion 54 is prevented.

The inner diameter of the inner peripheral portion (r in FIG. 2A) is, for example, 90% or more of the diameter of the wafer W placed on the annular holder 14. By setting the inner diameter of the inner peripheral portion to 90% or more of the diameter of the wafer W, the exposed area on the back surface of the wafer W becomes large, and the wafer W can be heated with high efficiency and uniformly. The inner diameter of the inner peripheral portion is preferably 95% or more of the diameter of the wafer W placed on the annular holder 14.

Next, the action / effect of the vapor phase growth apparatus of the present embodiment will be described.

The characteristics of the epitaxial single crystal film formed on the surface of the wafer W, such as the film thickness, chemical composition, and crystallinity, depend on the temperature of the wafer. Therefore, when the temperature variation in the wafer surface becomes large, the characteristics of the film vary in the surface of the wafer W. Therefore, it is desired to improve the temperature uniformity in the wafer surface.

3, FIG. 4, FIG. 5, and FIG. 6 are explanatory views of the operation and effect of the vapor phase growth apparatus of the present embodiment.

FIG. 3 is a schematic view of a state in which the wafer W is placed on the annular holder 15 in the comparative form. A state in which the wafer W is placed in the center of the annular holder 15 is shown. FIG. 3A is a top view, and FIG. 3B is a cross-sectional view taken along the line AA'of FIG. 3A. In FIG. 3A, the position of the inner end portion (E1 in FIG. 3B) of the inner peripheral portion 52 is indicated by a dotted line.

The annular holder 15 of the comparative embodiment is different from the annular holder 14 of the present embodiment in that the annular holder 15 of the present embodiment does not have the annular convex portion 54 of the present embodiment on the upper surface of the inner peripheral portion 53.

The outer peripheral region of the back surface of the wafer W is in contact with the upper surface 53a of the inner peripheral portion 53. The wafer W is heated from the back surface side by the in-heater 24 and the out-heater 26 during the film formation. Heat conduction occurs between the back surface of the wafer W and the annular holder 14 via the upper surface 53a.

When the wafer W is lower than the annular holder 15, heat is conducted from the annular holder 15 to the wafer W. On the contrary, when the wafer W has a higher temperature than the annular holder 15, heat is conducted from the wafer W to the annular holder 15.

In FIG. 3, the wafer W is placed in the center of the annular holder 15. Therefore, the outer peripheral region of the back surface of the wafer W is evenly in contact with the upper surface 53a. In other words, the contact area between the outer peripheral region of the back surface of the wafer W and the second upper surface 53a is uniform in the circumferential direction of the wafer W.

Therefore, the heat conduction between the annular holder 15 and the wafer W in the outer peripheral region of the wafer W occurs uniformly regardless of the position in the circumferential direction of the wafer W. Therefore, the variation in temperature in the circumferential direction of the wafer W becomes small. For example, the temperatures of the region X and the region Y in FIG. 3A are substantially the same.

FIG. 4 is a schematic view of a state in which the wafer W is placed on the annular holder 15 in the comparative form. The state in which the wafer W is placed so as to be offset from the center of the annular holder 15 is shown. 4 (a) is a top view, and FIG. 4 (b) is a cross-sectional view taken along the line AA'of FIG. 4 (a).

During the film formation of the wafer W, the annular holder 15 rotates with the wafer W placed on it. At this time, the wafer W may be displaced from the center of the annular holder 15 due to the centrifugal force applied to the wafer W. At this time, for example, as shown in FIG. 4B, a part of the end portion of the outer peripheral region of the wafer W comes into contact with the inner peripheral surface E2 of the outer peripheral portion 51.

As shown in FIG. 4, when the wafer W is placed on the annular holder 15 with a deviation from the center of the annular holder 15, the outer peripheral region of the back surface of the wafer W is unevenly in contact with the upper surface 53a of the inner peripheral portion. It will be. Specifically, since the wafer W is pushed to one side of the annular holder 15, in the region Y in FIG. 4A, the contact area between the wafer W and the upper surface 53a of the inner peripheral portion is the contact area in the region X. It is larger than. That is, the contact area between the outer peripheral region of the back surface of the wafer W and the upper surface 53a of the inner peripheral portion becomes non-uniform in the circumferential direction of the wafer W.

Therefore, the heat conduction between the annular holder 15 and the wafer W in the outer peripheral region of the wafer W occurs non-uniformly depending on the position of the wafer W in the circumferential direction. Therefore, the temperature variation in the circumferential direction of the wafer W becomes large. For example, the temperature difference between the temperature of the region X and the temperature of the region Y in FIG. 4A becomes large.

FIG. 5 is a schematic view of a state in which the wafer W is placed on the annular holder of the present embodiment. The state where the wafer W is placed in the center of the annular holder 14 is shown. 5 (a) is a top view, and FIG. 5 (b) is a cross-sectional view taken along the line AA'of FIG. 5 (a). In FIG. 5 (a), the inner end portion (corresponding to E1 in FIG. 5 (a)) and the outer end portion E3 of the annular convex portion 54 are shown by dotted lines.

The outer peripheral region of the back surface of the wafer W is in contact with the upper surface of the annular convex portion 54. The wafer W is heated from the back surface side by the in-heater 24 and the out-heater 26 during the film formation. Heat conduction occurs between the back surface of the wafer W and the annular holder 14 via the upper surface of the annular convex portion 54.

In FIG. 5, the wafer W is placed in the center of the annular holder 14. Therefore, the outer peripheral region of the back surface of the wafer W uniformly contacts the upper surface of the annular convex portion 54. Therefore, the heat conduction between the annular holder 14 and the wafer W in the outer peripheral region of the wafer W occurs uniformly regardless of the position in the circumferential direction of the wafer W. Therefore, the variation in temperature in the circumferential direction of the wafer W becomes small. For example, the temperatures of the region X and the region Y in FIG. 5A are substantially the same.

FIG. 6 is a schematic view of a state in which the wafer W is placed on the annular holder of the present embodiment. The state where the wafer W is deviated from the center of the annular holder 14 is shown. 6 (a) is a top view, and FIG. 6 (b) is a cross-sectional view taken along the line AA'of FIG. 6 (a).

As in the case of the comparative form, for example, as shown in FIG. 6B, a part of the end portion of the outer peripheral region of the wafer W comes into contact with the inner peripheral surface E2 of the outer peripheral portion 50. The outer peripheral region of the back surface of the wafer W is uniformly in contact with the upper surface of the annular convex portion 54 even if the wafer W deviates from the center. Specifically, since the width of the annular convex portion 54 is limited, even if the wafer W deviates from the center, the contact area between the outer peripheral region of the back surface of the wafer W and the annular convex portion 54 is the same as that of the wafer W. It becomes uniform in the circumferential direction.

Therefore, even if the wafer W deviates from the center, the temperature variation in the circumferential direction of the wafer W is small. For example, the temperatures of the region X and the region Y in FIG. 6A are substantially the same.

FIG. 7 is an explanatory diagram of the operation and effect of the vapor phase growth apparatus of the present embodiment. The horizontal axis of FIG. 7 represents the position of the wafer W in the circumferential direction in terms of phase (angle). The vertical axis of FIG. 7 is the emission peak wavelength of the MQW (Multi Quantum Well) layer for the LED (Light Emitting Diode) formed on the wafer W. The measured value is at a position 90 mm from the center of the wafer W. The radius of the wafer W is 100 mm.

The MQW layer is a laminated film of an indium gallium nitride (InGaN) film and a gallium nitride (GaN) film. The emission peak wavelength is determined by irradiating the wafer W with excitation light and measuring the wavelength of fluorescence emitted from the MQW layer. FIG. 7 shows the dependence of the emission peak wavelength on the outer peripheral portion of the wafer W in the circumferential direction.

When the annular holder 15 of the comparative form is used, the variation in the emission peak wavelength in the circumferential direction is about 7 nm. On the other hand, when the annular holder 14 of the present embodiment is used, the variation in the emission peak wavelength in the circumferential direction is about 3.5 nm. By using the annular holder 14 of the present embodiment, the variation in the emission peak wavelength in the circumferential direction is halved.

The emission peak wavelength of the MQW layer depends on the temperature of the wafer W. For example, the higher the temperature of the wafer W at the time of film formation, the shorter the emission peak wavelength. Therefore, it is considered that the temperature variation in the circumferential direction of the outer peripheral portion of the wafer W is reduced by using the annular holder 14 of the present embodiment.

The annular convex portion 54 of the annular holder 14 of the present embodiment is annular. Therefore, the back surface of the wafer W is continuously in close contact with the annular convex portion 54. Therefore, it is suppressed that the gas during film formation flows between the back surface of the wafer W and the annular holder 14. Therefore, the flow of gas during film formation between the inside and the outside of the rotating body unit 16 is suppressed.

If a gas flow occurs from the inside of the rotating body unit 16 to the outside, contamination from a member such as a heater in the rotating body unit 16 may be taken into the film on the wafer W, and the characteristics of the film may deteriorate. .. Further, if a gas flow occurs from the outside to the inside of the rotating body unit 16, the process gas may etch a member such as a heater in the rotating body unit 16 or cause deposits on the member such as the heater. There is a fear. If the member is etched or deposits are formed on the member, the life of the member may be shortened, the film forming conditions may be changed, and the characteristics of the film may be deteriorated.

Etching of the member becomes a particular problem when _{H 2 or ammonia gas having high activity is used as the process gas.}

According to the annular holder 14 of the present embodiment, by suppressing the flow of gas in the film between the inside and the outside of the rotating body unit 16, the life of the member is extended and the characteristics of the film to be formed are stabilized. realizable.

As described above, according to the vapor phase growth apparatus of the present embodiment, it is possible to improve the temperature uniformity of the wafer by reducing the temperature variation in the circumferential direction of the outer peripheral region of the wafer W. In addition, it is possible to extend the life of the member and stabilize the characteristics of the film to be formed.

(Second embodiment)
In the vapor phase growth device of the present embodiment, in the vertical cross section of the outer peripheral portion, a part of the inner end portion of the outer peripheral portion protrudes inside the outer peripheral portion than another part of the inner end portion of the outer peripheral portion. Other than that, it is the same as that of the first embodiment. Therefore, the description of the content that overlaps with the first embodiment will be omitted.

FIG. 8 is a schematic cross-sectional view of a part of the annular holder of the present embodiment. FIG. 8A shows a state in which the wafer W is placed in the center of the annular holder 14. FIG. 8B shows a state in which the wafer W is placed offset from the center of the annular holder 14.

In the annular holder 14 of the present embodiment, in the vertical cross section of the outer peripheral portion 50, a part of the inner end portion (E2 in FIG. 8) of the outer peripheral portion 50 is another part of the inner end portion of the outer peripheral portion 50. It protrudes inward of the outer peripheral portion 50. Specifically, the upper end portion inside the outer peripheral portion 50 protrudes, and a recess 50c is formed on the inner peripheral surface of the outer peripheral portion 50. In other words, the inner upper end of the outer peripheral portion 50 has an overhang shape.

For example, in the case of the annular holder 14 of the first embodiment, when the wafer W deviates from the center of the annular holder 14 as shown in FIG. 6, a part of the end portion of the wafer W becomes an inner end portion of the outer peripheral portion 50. It comes into contact with (E2 in FIG. 6B). In this case, heat conduction occurs between the end portion of the wafer W and the annular holder 14 via the inner end portion E2 of the outer peripheral portion 50.

Therefore, there is a possibility that a temperature difference may occur between the region where the end portion of the wafer W and the annular holder 14 are in contact with each other and the region where the end portion of the wafer W and the annular holder 14 are not in contact with each other. Specifically, the temperature difference between the region X and the region Y in FIG. 6A may become large.

In the annular holder 14 of the present embodiment, the upper end portion inside the outer peripheral portion 50 protrudes. Therefore, as shown in FIG. 8B, the contact area between the wafer W and the outer peripheral portion 50 is smaller than that in the first embodiment.

Therefore, heat conduction between the end portion of the wafer W and the annular holder 14 via the inner end portion E2 of the outer peripheral portion 50 is suppressed. Therefore, the temperature variation in the circumferential direction of the outer peripheral region of the wafer W is reduced.

As described above, the present embodiment is effective even when there is no annular convex portion 54 in that the heat inflow that is not uniform in the circumferential direction from the outer peripheral portion 50 is reduced. When the present embodiment is used in a form without the annular convex portion 54, the contact between the back surface of the wafer W and the upper surface 52a of the inner peripheral portion 52 is such that the wafer W is placed so as to be centered with respect to the annular holder 14. And it tends to be non-uniform in the circumferential direction. In order to avoid this, it is preferable that the diameter of the inner end E2 of the outer peripheral portion 50 is as close as possible to the diameter of the wafer W. By doing so, it is possible to reduce the degree to which the wafer W deviates from the center with respect to the annular holder 14. By doing so, the thermal contact between the wafer W and the inner peripheral surface E2 of the outer peripheral portion 50 can be reduced while maintaining the uniformity of the contact between the back surface of the wafer W and the upper surface 52a of the inner peripheral portion 52 in the circumferential direction. Then, the non-uniformity of the heat inflow from the inner peripheral surface E2 to the wafer W in the circumferential direction can be reduced, and the temperature uniformity in the circumferential direction of the outer peripheral portion of the wafer W is improved.

(Modification example)
FIG. 9 is a schematic cross-sectional view of a part of the annular holder of the modified example of the present embodiment. FIG. 9A shows a state in which the wafer W is placed in the center of the annular holder 14. FIG. 9B shows a state in which the wafer W is placed offset from the center of the annular holder 14.

In the annular holder 14 of the modified example of the present embodiment, the upper end portion inside the outer peripheral portion 50 protrudes in an acute angle shape. The same effect as that of this embodiment is realized by the annular holder 14 of the modified example of this embodiment.

As described above, according to the vapor phase growth apparatus of the present embodiment and the modified example, it is possible to further reduce the temperature variation in the circumferential direction of the outer peripheral region of the wafer W as compared with the first embodiment, and therefore, further. , It is possible to improve the temperature uniformity of the wafer.

As described above, the modified example is effective even when there is no annular convex portion 54 in that the heat inflow that is not uniform in the circumferential direction from the outer peripheral portion 50 is reduced. When the present embodiment is used in a form without the annular convex portion 54, the contact between the back surface of the wafer W and the upper surface 52a of the inner peripheral portion 52 is such that the wafer W is placed so as to be centered with respect to the annular holder 14. And it tends to be non-uniform in the circumferential direction. In order to avoid this, it is preferable that the diameter of the inner end E2 of the outer peripheral portion 50 is as close as possible to the diameter of the wafer W. By doing so, it is possible to reduce the degree to which the wafer W deviates from the center with respect to the annular holder 14. By doing so, the thermal contact between the wafer W and the inner peripheral surface E2 of the outer peripheral portion 50 can be reduced while maintaining the uniformity of the contact between the back surface of the wafer W and the upper surface 52a of the inner peripheral portion 52 in the circumferential direction. Then, the non-uniformity of the heat inflow from the inner peripheral surface E2 to the wafer W in the circumferential direction can be reduced, and the temperature uniformity in the circumferential direction of the outer peripheral portion of the wafer W is improved.

(Third Embodiment)
The vapor phase growth apparatus of the present embodiment is the same as that of the first embodiment except that it protrudes inward of the outer peripheral portion and has a plurality of island-shaped convex portions separated from the annular convex portion. Therefore, the description of the content that overlaps with the first embodiment will be omitted.

FIG. 10 is a schematic view of the annular holder of the present embodiment. 10 (a) is a top view, and FIG. 10 (b) is a cross-sectional view taken along the line AA'of FIG. 10 (a).

The annular holder 14 of the present embodiment has a plurality of islands protruding inward of the outer peripheral portion 50 at the inner end portion (E2 in FIG. 10B) of the outer peripheral portion 50 in the horizontal cross section of the outer peripheral portion 50. It has a convex portion 56. For example, island-shaped convex portions 56 projecting in the central direction are provided at eight locations on the inner peripheral surface E2 of the outer peripheral portion 50. The plurality of island-shaped convex portions 56 are separated from the annular convex portion 54.

FIG. 11 is an explanatory diagram of the operation and effect of the vapor phase growth apparatus of the present embodiment. When the wafer W deviates from the center of the annular holder 14, the end portion of the wafer W and the inner peripheral surface of the outer peripheral portion 50 come into contact with each other only by the island-shaped convex portion 56. Therefore, as compared with the case of the first embodiment shown in FIG. 6, the contact area between the end portion of the wafer W and the inner peripheral surface of the outer peripheral portion 50 is smaller. Therefore, the temperature variation in the circumferential direction of the outer peripheral portion of the wafer W is further reduced.

The number of island-shaped convex portions 56 is not necessarily limited to eight, and may be less than eight or more than eight. However, when the wafer W deviates from the center of the annular holder 14, it is desirable that the end portion of the wafer W always contacts the convex portion 56. From this point of view, it is desirable that the number of island-shaped convex portions 56 is at least three or more.

According to the vapor phase growth apparatus of the present embodiment, it is possible to further reduce the temperature variation in the circumferential direction of the outer peripheral region of the wafer W as compared with the first embodiment, and therefore, the temperature of the wafer can be further reduced. It is possible to improve the uniformity.

As described above, the present embodiment is effective even when there is no annular convex portion 54 in that the heat inflow that is not uniform in the circumferential direction from the outer peripheral portion 50 is reduced. When the present embodiment is used in a form without the annular convex portion 54, the contact between the back surface of the wafer W and the upper surface 52a of the inner peripheral portion 52 is such that the wafer W is placed so as to be centered with respect to the annular holder 14. And it tends to be non-uniform in the circumferential direction. In order to avoid this, it is preferable that the diameter of the inner end E2 of the outer peripheral portion 50 is as close as possible to the diameter of the wafer W. By doing so, it is possible to reduce the degree to which the wafer W deviates from the center with respect to the annular holder 14. By doing so, the thermal contact between the wafer W and the inner peripheral surface E2 of the outer peripheral portion 50 can be reduced while maintaining the uniformity of the contact between the back surface of the wafer W and the upper surface 52a of the inner peripheral portion 52 in the circumferential direction. Then, the non-uniformity of the heat inflow from the inner peripheral surface E2 to the wafer W in the circumferential direction can be reduced, and the temperature uniformity in the circumferential direction of the outer peripheral portion of the wafer W is improved.

(Fourth Embodiment)
The vapor phase growth apparatus of the present embodiment is the same as that of the third embodiment except that a concave portion is formed in the vertical cross section of the island-shaped convex portion protruding in the central direction. Therefore, the description of the content that overlaps with the third embodiment will be omitted.

FIG. 12 is a schematic cross-sectional view of a part of the annular holder of the present embodiment. A state in which the wafer W is placed in the center of the annular holder 14 is shown.

In the annular holder 14 of the present embodiment, a part of the island-shaped convex portion 56 protrudes in the vertical cross section of the island-shaped convex portion 56. Specifically, the upper portion of the island-shaped convex portion 56 protrudes inward from the lower portion of the island-shaped convex portion 56, and the concave portion 56c is formed. In other words, the upper part of the island-shaped convex portion 56 has an overhang shape.

According to the annular holder 14 of the present embodiment, the contact area between the end portion of the wafer W and the inner end portion of the outer peripheral portion 50 is smaller than that in the case of the first, second and third embodiments. Therefore, it is possible to further reduce the temperature variation in the circumferential direction of the outer peripheral portion of the wafer W, and thus it is possible to further improve the temperature uniformity of the wafer.

As described above, the present embodiment is effective even when there is no annular convex portion 54 in that the heat inflow that is not uniform in the circumferential direction from the outer peripheral portion 50 is reduced. When the present embodiment is used in a form without the annular convex portion 54, the contact between the back surface of the wafer W and the upper surface 52a of the inner peripheral portion 52 is such that the wafer W is placed so as to be centered with respect to the annular holder 14. And it tends to be non-uniform in the circumferential direction. In order to avoid this, it is preferable that the diameter of the inner end E2 of the outer peripheral portion 50 is as close as possible to the diameter of the wafer W. By doing so, it is possible to reduce the degree to which the wafer W deviates from the center with respect to the annular holder 14. By doing so, the thermal contact between the wafer W and the inner peripheral surface E2 of the outer peripheral portion 50 can be reduced while maintaining the uniformity of the contact between the back surface of the wafer W and the upper surface 52a of the inner peripheral portion 52 in the circumferential direction. Then, the non-uniformity of the heat inflow from the inner peripheral surface E2 to the wafer W in the circumferential direction can be reduced, and the temperature uniformity in the circumferential direction of the outer peripheral portion of the wafer W is improved.

(Fifth Embodiment)
The vapor phase growth apparatus of the present embodiment is the same as that of the first embodiment except that the annular convex portion is provided at a predetermined distance from the inner circumference of the inner peripheral portion. In other words, it is the same as the first embodiment except that the inner end of the annular convex portion is not flush with the inner end of the inner peripheral portion. Therefore, the description of the content that overlaps with the first embodiment will be omitted.

FIG. 13 is a schematic cross-sectional view of a part of the annular holder of the present embodiment. A state in which the wafer W is placed in the center of the annular holder 14 is shown.

In the annular holder 14 of the present embodiment, the inner end portion (E1 in FIG. 13) of the inner peripheral portion 52 and the annular convex portion 54 are separated by a predetermined distance. In other words, the inner circumference of the inner peripheral portion 52 protrudes inward from the annular convex portion 54.

The temperature of the outer peripheral portion of the wafer W depends on the amount of heat transferred by heat conduction between the wafer W and the annular holder 14. For example, when the temperature of the annular holder 14 becomes higher than that of the wafer W during film formation, the temperature of the outer peripheral portion of the wafer W may become too high compared to other parts due to heat conduction from the annular holder 14 to the wafer W. There is. In particular, when an annular outheater 26 for heating the outer peripheral region of the wafer W is provided, this tendency becomes remarkable.

According to the annular holder 14 of the present embodiment, the inner peripheral portion 52 protruding inward from the annular convex portion 54 shields the radiant heat from the in-heater 24 and the out-heater 26, which are the outer peripheral portions of the wafer W. Therefore, it is possible to prevent the temperature of the outer peripheral portion of the wafer W from becoming higher than that of the other portions. Therefore, it is possible to further improve the temperature uniformity of the wafer.

This embodiment includes a second embodiment shown in FIG. 8, a modified example of the second embodiment shown in FIG. 9, a third embodiment shown in FIG. 10, and a fourth embodiment shown in FIG. It may be used in combination with an embodiment or the like. By combining this embodiment with other embodiments, it is possible to simultaneously improve the temperature distribution in the circumferential direction and the radial direction in the vicinity of the outer periphery of the wafer W.

The embodiments of the present invention have been described above with reference to specific examples. The above-described embodiment is merely given as an example, and does not limit the present invention. In addition, the components of each embodiment may be combined as appropriate.

For example, in the embodiment, a single-wafer type vapor deposition apparatus has been described as an example, but if the apparatus uses an annular holder 14, it is not limited to the single-wafer type, and is a batch type that simultaneously forms a film on a plurality of wafers W. The present invention can also be applied to a vapor phase growth apparatus.

For example, in the embodiment, a case where a laminated film in which a plurality of indium gallium nitride films and a plurality of gallium nitride films are laminated on a GaN film is epitaxially grown has been described as an example. The present invention can also be applied to the formation of a single crystal film of other group III-V nitride semiconductors such as AlGaN). The present invention can also be applied to group III-V semiconductors such as GaAs. Furthermore, the present invention can also be applied to film formation of other films.

Further, although the case where the process gas is mixed in the shower plate has been described as an example, the configuration may be such that the process gas is mixed before entering the shower plate. Further, the process gas may be separated until it is ejected from the shower plate into the reaction chamber.

Further, although the case where the outer peripheral portion 50 and the inner peripheral portion 52 of the annular holder 14 are integrally molded has been described as an example, the annular holder 14 has a structure in which the inner peripheral portion 52 or a part thereof can be separated. I do not care. By making the inner peripheral portion 52 or a part thereof separable, for example, an annular holder 14 having various shapes can be applied, and fine adjustment of the temperature distribution on the outer peripheral portion of the wafer W becomes easy.

Further, although the case where two types of heaters, an in-heater 24 and an out-heater 26, is provided as an example has been described, only one type of heater may be used.

In the embodiment, the description of parts that are not directly required for the description of the present invention, such as the device configuration and the manufacturing method, is omitted, but the required device configuration, the manufacturing method, and the like can be appropriately selected and used. In addition, all vapor deposition apparatus having the elements of the present invention and which can be appropriately redesigned by those skilled in the art are included in the scope of the present invention. The scope of the present invention is defined by the scope of claims and the scope of their equivalents.

10 Reaction chamber 11 First gas supply path 12 Second gas supply path 14 Ring holder 24 In-heater (heater)
50 Outer circumference 50c Recessed portion 52 Inner peripheral portion 54 Circular convex portion 56 Island-shaped convex portion 56c Recessed portion W Wafer (board)

Claims (6)

Reaction room and
An annular holder provided in the reaction chamber on which a substrate is placed, which has an annular outer peripheral portion forming an outer peripheral portion and an annular convex portion forming an inner peripheral portion and separated from the outer peripheral portion at the upper portion. An annular holder having an inner peripheral portion and having an upper surface of the outer peripheral portion above the upper surface of the annular convex portion.
A heater provided below the annular holder and
With
In a state where a part of the end portion of the outer peripheral region of the substrate placed on the annular holder is in contact with the inner peripheral surface of the outer peripheral portion, the entire upper surface of the annular convex portion is in contact with the back surface of the substrate. ,
The annular holder has a recess on the inner peripheral surface of the outer peripheral portion.
A vapor deposition apparatus in which the amount of protrusion of the outer peripheral portion inward on the inner peripheral surface of the outer peripheral portion is maximum on the upper surface of the outer peripheral portion in the radial cross section of the annular holder including the recess. The vapor phase growth apparatus according to claim 1, wherein the height of the annular convex portion is smaller than the width of the annular convex portion in the radial cross section of the annular holder. The vapor phase growth apparatus according to claim 1 or 2, wherein the recess is provided on the entire circumference of the inner peripheral surface of the outer peripheral portion. Claim 1 or claim that the annular holder has a plurality of island-shaped convex portions that protrude inward of the outer peripheral portion and are separated from the annular convex portion, and the concave portion is provided on the island-shaped convex portion. 2. The vapor phase growth apparatus according to 2. The vapor phase growth apparatus according to any one of claims 1 to 4, wherein the annular convex portion is provided at a predetermined distance from the inner circumference of the inner peripheral portion. The vapor phase growth apparatus according to any one of claims 1 to 5, wherein the upper surface of the annular convex portion is a flat surface.

Images