This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2013-191116, filed Sep. 13, 2013; the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a vapor phase growth apparatus and a vapor phase growth method.
A vapor phase growth apparatus used for the fabrication of semiconductor devices such as a light emitting device and a High Electron Mobility Transistor (HEMT) is one of important apparatuses when a high quality film is formed. Particularly, in an apparatus for performing metal organic chemical vapor deposition (MOCVD), a multitude of wafers may be processed at a time for the purpose of mass production. In a vapor phase growth apparatus, a plurality of substrate holding portions is provided on a susceptor on which a wafer is arranged. Film formation may be performed on a multitude of wafers at a time by arranging a wafer on each of a plurality of substrate holding portions.
The susceptor has a rotating mechanism in order to perform uniform film formation on a plurality of wafers on the susceptor. Further, each of the substrate holding portions on the susceptor also has a rotating mechanism. The substrate holding portion is rotatably supported on the susceptor through a bearing. In the vapor phase growth apparatus, when raw-material gas flows into the housing of the bearing, and deposit adheres to the surface of the bearing, the rotation of the substrate holding portion is affected. In the vapor phase growth apparatus, it is important to keep the function of the bearing for a long time.
It is an object of an exemplary embodiment of the present disclosure to provide a vapor phase growth apparatus and a vapor phase growth method capable of maintaining function of a bearing that supports a substrate holding portion for a long time.
According to one embodiment, a vapor phase growth apparatus includes a susceptor in a chamber, the susceptor configured to rotate on an axis perpendicular to a surface of the susceptor, a plurality of substrate holding portions above the susceptor, each of the substrate holding portions configured to revolve around the axis by the rotation of the susceptor and configured to rotate circumferentially, a plurality of bearings arranged in a housing between the susceptor and the substrate holding portion, and a plurality of blade portions on the outer periphery of the substrate holding portion, each of the blade portions extending radially from the center of the substrate holding portion.
According to another embodiment, a vapor phase growth apparatus includes a susceptor in a chamber, the susceptor configured to rotate on an axis perpendicular to a surface of the susceptor, a plurality of substrate holding portions above the susceptor, each of the substrate holding portions configured to revolve around the axis by the rotation of the susceptor and configured to rotate circumferentially, a plurality of bearings arranged in a housing between the susceptor and the substrate holding portion, and a non-contact sealing portion including a part of susceptor, a part of the substrate holding portion, and a gap between the substrate holding portion and the susceptor and provided outside the housing.
Exemplary embodiments of the present disclosure will be described below with reference to the accompanying drawings. In the following description, the same symbols are assigned to the same elements and their description is not repeated as appropriate.
As shown in
The vapor phase growth apparatus 110 further includes a chamber 1 and a heater 50. The susceptor 10 rotates around an axis c1 in the chamber 1. As shown in
The substrate holding portion 20 is provided on the susceptor 10. In examples shown in
A gear, not shown, is provided on the outer periphery of the disk-like substrate holding portion 20. The gear of the substrate holding portion 20 engages with a gear provided inside a ring member, not shown, that is arranged so as to surround the outer periphery of the susceptor 10. When the substrate holding portion 20 revolves caused by the rotation of the susceptor 10, the gear of the substrate holding portion 20 engages with the gear of the ring member, thus the substrate holding portion 20 rotates on its axis.
The bearings 30 are arranged in a housing 35 provided between the susceptor 10 and the substrate holding portion 20. The bearings 30 are arranged near the outer periphery of substrate holding portion 20 on the side of the susceptor 10. The substrate holding portion 20 is put on the bearings 30. In this manner, the substrate holding portion 20 rotates smoothly on the susceptor 10 by the rolling action of the bearings 30. For example, a wafer W to be processed is provided on the surface of the substrate holding portion 20.
The blade portions 40 are provided on the outer periphery of the substrate holding portion 20. Each of the blades 40 includes a portion extending radially from the center of the substrate holding portion 20.
In order to perform vapor phase growth using the vapor phase growth apparatus 110, first, a wafer W is put on the substrate holding portion 20 on the susceptor 10, and the susceptor 10 and the substrate holding portion 20 are rotated. Then, the wafer W is heated by the heater 50. And then, a raw-material gas GS1 is introduced in the chamber 1. In this manner, the raw-material gas GS1 reacts on the heated wafer W, and a film having prescribed composition is formed according to the component of the raw-material gas.
As shown in
A depressed portion 20a is provided in the center of the substrate holding portion 20. On the other hand, a projecting portion 12a is provided in the center of the tray portion 12. The depressed portion 20a in the substrate holding portion 20 is put on the projecting portion 12a in the tray portion 12. The inner diameter of the depressed portion 20a is slightly larger than the contour of the projecting portion 12a.
Further, a housing 35 of the bearing 30 is provided between the substrate holding portion 20 and the tray portion 12. The housing 35 is provided on the tray portion 12 side on the outer periphery of the substrate holding portion 20. The housing 35 surrounds the outside of the projecting portion 12a in the tray portion 12. The predetermined number of the bearings 30 is arranged in the housing 35. For example, the bearings 30 are arranged on the circumference through the center of the housing 35 by a ratio of approximately 60% to 80% of the circumference.
The diameter of each of the bearings 30 is slightly larger than a height of the projecting portion 12a in the tray portion 12. Therefore, when the bearings 30 are arranged on the housing 35, and the substrate holding portion 20 is put on the tray portion 12, the substrate holding portion 20 is supported by the bearings 30. When the substrate holding portion 20 is arranged on the tray portion 12 through the bearings 30, a gap is provided between the inner surface of the depressed portion 20a and the outer surface of the projecting portion 12a. This gap allows the substrate holding portion 20 to rotate smoothly on the tray portion 12 by the rolling action of the bearing 30.
A step 21 is provided on the opposite side (surface side) to the tray portion 12 of the substrate holding portion 20. A wafer W is put on the step 21.
An introduction opening 12h for counter gas GS2 is provided in the tray portion 12. Inert gas such as N2 is used for the counter gas GS2. The counter gas GS2 inhibits the gas GS1 for growth introduced in the chamber 1 from flowing into the bottom of the susceptor 10.
The introduction opening 12h is a through-hole that reaches the housing 35 of the bearing 30 from the outer peripheral surface (e.g., underside) of the tray portion 12. As shown in
As shown in
When such blade portions 40 are provided, and the substrate holding portion 20 rotates (on its axis), a pressure on the side of the housing 35 centered on the substrate holding portion 20 becomes higher than a pressure on the opposite side to the housing 35. That is, the rotation of the blade portions 40 generates the pressure difference between the front side and the back side of the substrate holding portion 20.
As shown in
When vapor phase growth is performed by the vapor phase growth apparatus 110, the raw-material gas GS1 is sent into the front side of the substrate holding portion 20. Here, assuming that the pressure generated by the raw-material gas GS1 flowing from the surface of the substrate holding portion 20 toward the housing 35 is set to be P1, and the pressure generated by the counter gas GS2 flowing from the housing 35 toward the surface of the substrate holding portion 20 is set to be P2 in the gap between the blade portion 40 and the body portion 11 of the susceptor 10, the blade portions 40 are provided so that the pressure P2 becomes higher than the pressure P1. This inhibits the raw-material gas GS1 from flowing into the housing 35 of the bearing 30 during vapor phase growth processing.
The vapor phase growth apparatus 110 according to the present embodiment inhibits the raw-material gas GS1 from flowing into the housing 35 of the bearing 30 due to generation of pressure difference by the blade portions 40, and inhibits deposit due to the raw-material gas GS1 from adhering to the surface of the bearing 30.
Next, a vapor phase growth apparatus according to a second embodiment will be described.
As shown in
In the vapor phase growth apparatus 120, the non-contact sealing member 60 inhibits raw-material gas GS1 from flowing into the housing 35 of the bearings 30 through the gap between the substrate holding portion 20 and the tray portion 12.
As shown in
In the non-contact sealing member 60, the gap between the substrate holding portion 20 and the tray portion 12 includes a first portion 61 and a second portion 62. The first portion 61 extends from a position 601 in communication with the housing 35 toward the substrate holding portion 20 (upper side). The second portion 62 extends toward the tray portion 12 side than the closest position to the substrate holding portion 20 in the first portion 61. That is, the first portion 61 rises up from the position 601 in communication with the housing 35. The second portion 62 falls down from the uppermost position of the first portion 61. There may be another portion (e.g., a portion where height does not change) between the first portion 61 and the second portion 62.
In the example shown in
In addition, it is desirable that, in the gap between the substrate holding portion 20 and the tray portion 12, the outermost position 602 in the non-contact sealing member 60 is separated from the surface side (the side where a wafer W is put on) of the substrate holding portion 20. When the position 602 is near to the surface of the substrate holding portion 20, the raw-material gas GS1 is likely to enter from the front side of the substrate holding portion 20. It is desirable that the position 602 is separated from the surface of the substrate holding portion 20 in order to enhance the sealing effect of the raw-material gas GS1. For example, the position 602 is provided on the side of the tray portion 12 than the position 601.
When vapor phase growth is performed by the vapor phase growth apparatus 120, the raw-material gas GS1 is sent into the front side of the substrate holding portion 20. Then, a wafer W is put on the substrate holding portion 20, and the susceptor 10 and the substrate holding portion 20 are rotated. The rotation of the substrate holding portion 20 generates a labyrinth effect in the non-contact sealing member 60. The labyrinth effect inhibits the raw-material gas GS1 from flowing into the housing 35.
In a non-contact sealing member 60B shown in
Note that the configuration of the non-contact sealing member 60 is not limited to the examples shown in
In the vapor phase growth apparatus 120 according to the present embodiment, such a sealing effect by the non-contact sealing member 60 can inhibit the raw-material gas GS1 from flowing into the housing 35 of the bearing 30, thus, inhibiting deposit due to the raw-material gas GS1 from adhering to the surface of the bearing 30.
Next, a vapor phase growth method according to a third embodiment will be described.
As shown in
In step S101, the wafer W is put on the substrate holding portion 20 on the susceptor 10. As the wafer W, a GaN substrate, a sapphire substrate, a SiC substrate, a GaAs substrate and an Si substrate may be used.
Next, in step S102, the susceptor 10 is rotated and the substrate holding portion 20 is also rotated. The substrate holding portion 20 revolves caused by the rotation of the susceptor 10, and rotates on its axis with respect to the susceptor 10. The wafer W also revolves and rotates on the axis thereof caused by the revolution and rotation of the substrate holding portion 20. Next, while the susceptor 10 and the substrate holding portion 20 are being rotated, the wafer W is heated by the heater 50. The heating temperature is between 600 degrees Celsius and 1,300 degrees Celsius, for example.
Next, in step S103, raw-material gas GS1 is introduced in the chamber 1. As gas GS1 for growth, for example, organic metal gas is used. As the raw-material gas GS1, trimethyl gallium (TMGa), trimethyl indium (TMI), aluminum trimethyl (TMA), silane (SiH4), arsine (AsH3), phosphine (PH3), ammoniacal (NH3) and the like are used. Note that N2 and H2 are used for carrier gas, for example.
For example, when semiconductor devices such as a Light Emitting Diode (LED), a Laser Diode (LD) and an HEMT are manufactured, TMI, TMG, TMA, SiH4 and NH3 are used to perform vapor phase growth of the GaN-based film, and TMI, TMG, TMA, SiH4, AsH3 and PH3 are used to perform vapor phase growth of the GaAs-based film.
Further, in step S103, the counter gas GS2 may be introduced in addition to the introduction of the gas GS1 for growth. Inert gas such as N2 is used for the counter gas GS2.
Next, in step S104, a film is formed on the surface of the wafer W in the chamber 1. That is, the raw-material gas GS1 introduced in the chamber 1 reacts on the surface of the wafer W to achieve the crystal growth of the film according to the material of the raw-material gas GS1 on the surface of the wafer W.
When the vapor phase growth apparatus 110 is used in the vapor phase growth method according to the present embodiment, by the rotation of the blade portions 40 caused by the rotation of the substrate holding portion 20, the pressure on the side of the housing 35 centered on the substrate holding portion 20 becomes higher than the pressure on the opposite side to the housing 35. This inhibits the raw-material gas GS1 from entering into the housing 35 during film formation, and also inhibits the counter-flow of the counter gas GS2.
When the vapor phase growth apparatus 120 is used in the vapor phase growth method according to the present embodiment, for example, pressure difference due to a labyrinth effect is generated between the inside of the housing 35 and the outside of the housing 35 by the rotation of the substrate holding portion 20. This inhibits the raw-material gas GS1 from entering into the housing 35 during film formation.
Using such a vapor phase growth method, the semiconductor devices including a light emitting device such as an LED, an HEMT and a power transistor are manufactured.
The vapor phase growth method according to the present embodiment effectively inhibits the raw-material gas GS1 from entering into the housing 35 of the bearing 30. This inhibits deposit due to the raw-material gas GS1 from adhering to the surface of the bearing 30. That is, inhibiting deposit from adhering to the surface of the bearing 30 reduces the interruption and stopping of the operation of the apparatus caused by the trouble of the bearing 30. Thus, semiconductor devices having high quality can be manufactured productively.
As described above, according to the vapor phase growth apparatus and the vapor phase growth method according to the embodiments, the function of the bearing 30 that supports the substrate holding portion 20 can be maintained for a long time.
Note that although the present embodiment and variations thereof have been described, the present disclosure is not limited to these exemplary embodiments. For example, an MOCVD is taken as an example for the vapor phase growth apparatuses 110 and 120, but a CVD other than an MOCVD can be applicable. In addition, addition, deletion and change of a configuration may be suitably made by those skilled in the art on each embodiment and variation described above, and features of each embodiment may be suitably combined, which are encompassed in the present disclosure, without departing from the spirit of the disclosure.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
Number | Date | Country | Kind |
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2013-191116 | Sep 2013 | JP | national |