JPH07183223A - Epitaxial growth device - Google Patents

Abstract

PURPOSE:To prevent the adhesion of products by thermal decomposition of a gaseous starting material to a positioning member which positions a semiconductor wafer holding tool put on a pedestal by positioning the positioning member on the upper surface of a pedestal section other than the flow passage of the gaseous starting material and/or a position where the temperature of the material gas does not reach the temperature at which the material gas is not decomposed thermally. CONSTITUTION:An epitaxial growth device is provided with a gas supplying means 12 having a gaseous starting material blowing port 12A at the front end part of a tube and a cylindrical member 20A which covers the base section of the means 12, with the front end of the means 12 protruded from the front end opening of the member 20A. In addition, an annular pedestal section 20B the inner peripheral surface of which is integrally fixed to the front end opening of the member 20A and which is extended in the radial direction of the member 20a from the front end opening and a positioning member 20C which is annularly protruded from the surface of the pedestal section 20B and positions a semiconductor wafer holding tool 21 on the surface of the section 20B other than the flow passage of the gaseous starting material blown out from the port 12A and/or a position where the temperature of the material gas does not reach the temperature at which the material gas is not decomposed thermally.

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Industrial Application Conventional Technology (FIGS. 4 to 6) Problem to be Solved by the Invention (FIGS. 7 and 8) Means for Solving the Problem (FIGS. 1 and 4) Action (FIGS. 1 and 4) ) Example (FIGS. 1 to 3) Effect of the invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epitaxial growth apparatus, and is particularly suitable for application to a vapor phase epitaxial growth apparatus.

[0003]

2. Description of the Related Art Conventionally, in a vapor phase epitaxial growth apparatus, a monosilane (Si) is used as a base on which a wafer is placed by a high frequency induction heating method (hereinafter referred to as a susceptor).
Some heat up to the thermal decomposition reaction temperature of H ₄ ) gas, and a single crystal such as silicon generated by heat is grown on a wafer. As shown in FIG. 4, the epitaxial growth apparatus 1 has a main structure of a container 2 that isolates the reaction chamber from the outside. Here, the container 2 is formed by an outer bell jar 2A having a viewing window 3 and an inner bell jar 2B provided further inside with a cooling layer 4 interposed therebetween.

A cylindrical work coil cover 6 having a shaft hole 5 extending vertically is formed at the center of the inner bell jar 2B. The work coil cover 6 separates the high frequency induction heating coil 7 mounted on the upper inside from the reaction chamber. A rotary shaft 8 is arranged at the bottom of a shaft hole 5 formed in the center of the work coil cover 6.

A disk holder 9 is provided above the rotary shaft 8.
The lower end of the shaft portion 9A is attached. A doughnut-shaped susceptor 10 made of carbon is placed above the disk holder 9 with the work coil cover 6 sandwiched between the induction heating coils 7 and 7.
It is arranged so as to approach. As a result, the susceptor 10 that is rotationally driven together with the disk holder 9 becomes the wafer 1.
It is designed to be heated uniformly with 1 being placed on it.

The disk holder 9 is made of quartz glass, and as shown in FIG. 5, a donut-shaped disk portion 9B is integrally formed on an upper portion of a cylindrical shaft portion 9A. Here, the outer diameter and the inner diameter of the shaft portion 9A are 31 [mm] and 23 [mm], respectively.
Is. Further, a convex ring portion 9C made of quartz glass is provided on the upper surface of the disk portion 9B at a position of about 35 [mm] toward the outer periphery from the rotation axis a of the disk portion 9B, that is, at a position of an outer diameter of about 70 [mm]. It is formed integrally with the disk portion 9B. Here, the thickness of the convex ring portion 9C in the radial direction is 3 to 4
[Mm], and the height in the direction of the rotation axis a is 7 to 8 [mm]. The inner peripheral portion of the susceptor 10 is fitted into the outer peripheral portion of the convex ring portion 9C with a slight gap, and the disc portion 9
It is mounted on the upper surface of B.

As shown in FIGS. 6 (A) and 6 (B), the susceptor 10 has a donut shape, and a 4-inch wafer 11 is arranged in a circular shape on the upper surface of the susceptor 10. . The inner diameter of the susceptor 10 is a convex ring portion 9C.
Is formed slightly larger than the outer diameter of.

A gas nozzle 12 is coaxially attached to the inside of the shaft portion 9A, and a part of the gas nozzle 12 projects above the disk portion 9B. This gas nozzle 12
Does not rotate because it is fixed, and a plurality of gas ejection holes 12 drilled upward when the disk holder 9 is rotating.
A monosilane gas 13 is ejected radially from A.

[0009]

The heat of the susceptor 10 heated by the induction heating coil 7 is transferred to the disk holder 9
The convex ring portion 9C is also transmitted to the convex ring portion 9C.
C reaches a temperature equal to or higher than the thermal decomposition reaction temperature of the monosilane gas 13. Further, the monosilane gas 13 supplied from the gas nozzle 12 directly flows into the convex ring portion 9C because there is no obstacle in the middle. As a result, the monosilane gas 13 supplied from the gas nozzle 12 causes a thermal decomposition reaction in the convex ring portion 9C as shown in FIG. 7, and the deposit (polysilicon) 14 fills the recessed portion extending from the upper portion of the convex ring portion 9C to the inner wall. Was attached as.

The amount of the deposit 14 is smaller as the temperature is closer to the rotation axis a and the thermal decomposition reaction is less likely to occur, and the amount closer to the rotation axis a is more likely to be separated. The exfoliated deposit 14 is diffused into the reaction chamber by the monosilane gas 13 and adheres onto the wafer 11 to form the wafer 1.
The electronic material or the like formed in No. 1 may be adversely affected. Therefore, the deposit 14 is removed by etching with a mixed solution of hydrofluoric acid and nitric acid.

However, if etching is repeated to remove the deposit 14, a microcrack 15 may occur on the surface of the convex ring portion 9C after the deposit 14 is removed, as shown in FIG. Dust 16 is easily generated from the minute cracks 15, and the dust 16 may be diffused into the reaction chamber by the monosilane gas 13 and adhere to the wafer 11. If the dust 16 adheres to the wafer 11 as described above, it may cause crystal defects in the process of forming the epitaxial growth layer, and the electronic material and the like formed on the wafer 11 may be adversely affected. As a result, the yield of electronic materials may decrease.

The present invention has been made in consideration of the above points, and prevents the pyrolysis products of the source gas from adhering to the positioning member for positioning the semiconductor wafer holder mounted on the pedestal. The proposed epitaxial growth apparatus is to be proposed.

[0013]

In order to solve such a problem, in the present invention, an epitaxial growth apparatus for thermally decomposing a source gas 13 to grow a single crystal layer on a semiconductor wafer 11 is provided in a reaction chamber 2B. A gas supply means 12 having a raw material gas ejection port 12A at the tip portion of the extending pipe, a tip of the gas supply means 12 is projected from the tip opening portion, and the root portion of the gas supply means 12 is covered following the tip opening portion. And an annular pedestal portion 20B having an inner peripheral surface integrally fixed to the tip opening and extending in the radial direction of the tubular member 20A from the tip opening.
From the surface of the pedestal portion 20B at the position avoiding the flow path of the raw material gas 13 ejected from the raw material gas ejection port 12A on the surface of the pedestal portion 20B and / or at the position where the temperature at which the thermal decomposition product of the raw material gas 13 does not occur Positioning member 20C that annularly projects toward the tip of the gas supply means 12 and positions the semiconductor wafer holder 21 placed on the pedestal portion 20B.
And to be provided.

[0014]

[Function] The source gas 13 ejected from the gas supply means 12
By disposing the positioning member 20C at a position other than the flow path of the above, it is possible to prevent the raw material gas 13 from flowing into the positioning member 20C and adhering the thermal decomposition product 14 of the raw material gas 13 to the positioning member 20C. obtain. This eliminates the need to remove the thermal decomposition product 14 adhering to the positioning member 20C, prevents the crystal defects due to the dust 16 generated from the minute cracks 15 due to the etching of the positioning member 20C, and the electronic material formed on the semiconductor wafer 11 and the like. It is possible to further prevent the yield reduction.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, in which parts corresponding to those in FIG. 5 are designated by the same reference numerals, 20 indicates a disk holder of the epitaxial growth apparatus as a whole. The disk holder 20 is made of quartz glass, and a donut-shaped disk portion 20B is integrally formed on an upper portion of a cylindrical shaft portion 20A.
Here, the outer diameter and the inner diameter of the shaft portion 20A are 31 [mm] and 23 [mm], respectively.

On the upper surface of the disk portion 20B, a convex ring portion 20C made of quartz glass and having an outer diameter much smaller than 70 [mm] is formed so that the monosilane gas 13 is not directly contacted.
Are integrally formed with the disk portion 20B. The radial thickness of the convex ring portion 20C is 3 to 4 [mm],
The height in the direction of the rotation axis a is 7 to 8 [mm].

The susceptor 21 is fitted in the outer peripheral portion of the convex ring portion 20C with a slight gap and is mounted on the upper surface of the disk portion 20B.

As shown in FIGS. 2A and 2B, the susceptor 21 has a donut shape, and a 4-inch wafer 11 is arranged in a circular shape on the upper surface of the susceptor 21. . The inner diameter of the susceptor 21 is slightly larger than the outer diameter of the convex ring portion 20C. Therefore, the susceptor 21 has an inner diameter smaller than that of the conventional susceptor 10 and an outer diameter equal to that of the conventional susceptor 10.

In the above structure, the susceptor 21 is fitted in the outer peripheral portion of the convex ring portion 20C so that the disk portion 20B is formed.
Mounted on the upper surface of the disk holder and rotates together with the disk holder 20.

Since the gas nozzle 12 is fixed, it does not rotate, and the monosilane gas 13 is ejected from a plurality of gas ejection holes 12A formed above the gas nozzle 12.

When the susceptor 21 is heated by the induction heating coil 7, the monosilane gas 13 flowing on the wafer 11 placed on the upper surface of the susceptor 21 causes a thermal decomposition reaction, and the generated silicon grows on the wafer 11. The monosilane gas 13 supplied from the gas nozzle 12 does not directly hit the convex ring portion 20C but passes above the convex ring portion 20C and flows toward the wafer 11 arranged on the upper surface of the susceptor 21. In this way, since the monosilane gas 13 does not flow directly into the inside of the convex ring portion 20C (that is, the concave portion), the deposit 14 of polysilicon is hardly attached to the convex ring portion 20C.

According to the above construction, by disposing the convex ring portion 20C at a position where the monosilane gas 13 cannot be sprayed from the gas ejection hole 12A of the gas nozzle 12,
It is possible to prevent the monosilane gas 13 from directly flowing into the inside of the convex ring portion 20C (that is, the concave portion) to attach the deposit 14 to the convex ring portion 20C.

As a result, the deposit 1 is formed on the convex ring portion 20C.
4 does not adhere, and it is not necessary to etch and remove the adhered deposit 14. Therefore, the convex ring portion 20C
16 generated from microcracks 15 due to etching of
It is possible to prevent crystal defects caused by the above and further prevent the yield of electronic materials and the like formed on the wafer 11 from decreasing. Further, since it is possible to prevent the minute cracks 15 from being generated in the disk holder 20, the life of the disk holder 20 can be extended.

In the above-described embodiment, the convex ring portion 20C made of quartz glass is arranged at a position on the upper surface of the disk portion 20B where the monosilane gas 13 does not directly contact, but the present invention is not limited to this. Alternatively, the same effect as described above can be obtained by disposing the convex ring portion made of quartz glass at a position on the upper surface of the disk portion 20B that has a temperature lower than the thermal decomposition reaction temperature of the monosilane gas 13. In this case, the monosilane gas 13 supplied from the gas nozzle 12 is not thermally decomposed on the inner side and the upper surface of the convex ring portion because the temperature of the position where the convex ring portion is installed is lower than the temperature required for the thermal decomposition. Therefore, the thermal decomposition product of the monosilane gas 13 is prevented from adhering to the convex ring portion.

Further, in the above-mentioned embodiment, the convex ring portion 20C made of quartz glass is arranged at a position on the upper surface of the disk portion 20B where the monosilane gas 13 does not directly contact, but the present invention is not limited to this. Alternatively, the convex ring portion made of quartz glass may be arranged at a position where the monosilane gas 13 does not directly contact the upper surface of the disk portion 20B and the temperature is lower than the thermal decomposition reaction temperature of the monosilane gas 13. In this case, the monosilane gas 13 hardly flows into the inside of the convex ring portion, and the same effect as described above can be obtained by not thermally decomposing on the inside and the upper surface of the convex ring portion.

For example, as shown in FIG. 3, the disk portion 30B
The inner diameter of the convex ring portion 30C and the inner diameter of the convex ring portion 30C may be aligned. At this time, the inner diameter of the susceptor 31 is equal to that of the convex ring portion 3.
It may be formed slightly larger than the outer diameter of 0C. The inner diameter of the convex ring portion may be smaller than the inner diameter of the disc portion as long as the disc portion has a gap between the gas nozzle and the convex ring portion so that the disc portion can rotate. Also at this time, the inner diameter of the doughnut-shaped susceptor may be formed slightly larger than the outer diameter of the convex ring portion.

Further, in the above-mentioned embodiment, the size of the wafer placed on the upper surface of the susceptor is 4 inches, but the present invention is not limited to this, and the semiconductor wafer having a size of 5 inches or more. It may be a susceptor for placing.

Further, in the above-mentioned embodiment, the case where the monosilane gas 13 is supplied as the source gas has been described, but the present invention is not limited to this, and can be applied to an epitaxial growth apparatus utilizing a source gas other than the monosilane gas.

Further, in the above-mentioned embodiment, the case where the susceptor is heated by the induction heating coil has been described, but the present invention is not limited to this, and the susceptor is of another type (for example, various lamps, various lasers, etc. are used). It can also be widely applied to an epitaxial growth apparatus that heats by.

[0031]

As described above, according to the present invention, the positioning member is provided on the upper surface of the pedestal portion at a position other than the flow path of the raw material gas and / or at a position at which the raw material gas is not thermally decomposed. Therefore, it is possible to realize the epitaxial growth apparatus capable of preventing the raw material gas from flowing into the positioning member and adhering the thermal decomposition product of the raw material gas to the positioning member.

[Brief description of drawings]

FIG. 1 is a sectional view for explaining a disk holder according to an embodiment of an epitaxial growth apparatus according to the present invention.

FIG. 2 is a schematic diagram used for explaining a shape of a susceptor to be mounted on the disk holder.

FIG. 3 is a sectional view for explaining a disk holder according to another embodiment.

FIG. 4 is a sectional view showing the overall configuration of an epitaxial growth apparatus.

FIG. 5 is a sectional view for explaining a conventional disk holder.

FIG. 6 is a schematic diagram for explaining a susceptor to be mounted on a conventional disk holder.

FIG. 7 is a cross-sectional view for explaining a state in which deposits are attached to the convex ring portion.

FIG. 8 is a cross-sectional view provided for explaining microcracks and dust generated in a convex ring portion by etching.

[Explanation of symbols]

1 ... Epitaxial growth device, 2 ... Container, 2A ...
Outer bergier, 2B ... Inner belger, 3 ...
Viewing window, 4 ... Cooling layer, 5 ... Shaft hole, 6 ... Work coil cover, 7 ... High frequency induction heating coil, 8 ... Rotating shaft, 9, 20, 30 ... Disk holder, 9A, 20
A, 30A ... Shaft, 9B, 20B, 30B ... Disk, 9C, 20C, 30C ... Convex ring, 10, 2
1, 31 ... Susceptor, 11 ... Wafer, 12 ... Gas nozzle, 12A ... Gas ejection hole, 13 ... Monosilane gas, 14 ... Deposit, 15 ... Microcrack, 16 ... Dust.

Claims (4)

[Claims] 1. An epitaxial growth apparatus for thermally decomposing a raw material gas to grow a single crystal layer on a semiconductor wafer, and a gas supply means having a raw material gas ejection port at a tip portion of a tube extending into a reaction chamber; A cylindrical member that projects the tip of the supply means from the tip opening and extends so as to cover the base portion of the gas supply means following the tip opening, and the inner peripheral surface integrally fixed to the tip opening. And a ring-shaped pedestal portion extending in the radial direction of the tubular member from the tip opening, and a position of the surface of the pedestal portion that avoids the flow path of the raw material gas ejected from the raw material gas ejection port and Alternatively, at a position where a temperature at which a thermal decomposition product of the raw material gas does not occur, a semiconductor wafer holding member that projects annularly from the surface of the pedestal portion in the direction of the tip of the gas supply means and is mounted on the pedestal portion An epitaxial growth apparatus comprising: a positioning member for positioning a tool; 2. The epitaxial growth apparatus according to claim 1, wherein the positioning member has a bottom surface integrally fixed to the tip opening portion or the pedestal portion. 3. The semiconductor wafer holder is fitted on the outer peripheral surface of the positioning member.
The epitaxial growth apparatus described in 1. 4. The epitaxial growth apparatus according to claim 1, wherein the semiconductor wafer holder holds a semiconductor wafer of 4 inches or more.