JPH0737813A - Epitaxial growth device - Google Patents

Abstract

PURPOSE:To avoid the adherence of a gaseous raw material cracked products to a positioning member positioning a semiconductor wafer holder mounted on a pedestal part within an epitaxial growth device. CONSTITUTION:This epitaxial growing device wherein the flow rate of a gaseous raw material jetted from a gas 22 feed means is blocked by a gas flow adjusting member 31 arranged between a gas feed means 21 and a positioning member 9C on a pedestal part 9B to prevent the gaseous raw material from directly running in the positioning member 9C thereby enabling the adherence of the cracked products of the gaseous raw material to the alignment part to be avoided can be realized. Through these procedures, the cracked products adhering to the positioning member 9C need not be removed so that the crystal defects due to the dust raised from fine cracks during the etching step of positioning member 9C may be avoided thereby enabling the decrease in the yield of electronic material, etc., formed on a semiconductor wafer to be further avoided.

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. 3 and 4) Problem to be Solved by the Invention (FIGS. 5 and 6) Means for Solving the Problem (FIG. 1) Action (FIG. 1) Example (FIG. 1) And Figure 2) 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. This 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 the cooling layer 4 (FIG. 3).

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. The lower end of the shaft portion 9A of the disk holder 9 is mounted on the upper portion of the rotary shaft 8. A donut-shaped susceptor 10 made of carbon is arranged above the disk holder 9 so as to approach the induction heating coil 7 with the work coil cover 6 interposed therebetween. As a result, the susceptor 10 which is rotationally driven together with the disk holder 9 is heated uniformly.

The disk holder 9 is made of quartz glass, and as shown in FIG. 4, 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 35 [mm] and 23 [mm], respectively.
Is. Further, a convex ring portion 9C having an outer diameter of 72 [mm] is formed integrally with the disc portion 9B on the upper surface of the disc portion 9B at a position of 36 [mm] toward the outer circumference from the rotary shaft 20 of the disc portion 9B. ing. Here, the convex ring portion 9C
The thickness in the radial direction is 3 to 4 [mm], and the height in the direction of the rotating shaft 20 is about 7 [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 is mounted on the upper surface of the disk portion 9B.

A gas nozzle 21 is coaxially attached to the inside of the shaft portion 9A, and a part of the gas nozzle 21 projects above the disk portion 9B. This gas nozzle 21
Does not rotate, and when the disk holder 9 is rotating, the monosilane gas 22 is radially ejected from a plurality of gas ejection holes 21A that are bored upward.

[0007]

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 above the thermal decomposition reaction temperature of the monosilane gas 22 (about 1030 [° C.] here). Also gas nozzle 2
The monosilane gas 22 supplied from No. 1 directly flows into the convex ring portion 9C because there is no obstacle in the middle. As a result, the monosilane gas 2 supplied from the gas nozzle 21
As shown in FIG. 5, No. 2 caused a thermal decomposition reaction in the convex ring portion 9C, and the deposit (polysilicon) 23 was attached so as to fill the recessed portion extending from the upper portion of the convex ring portion 9C to the inner wall.

The amount of the deposit 23 is small because the temperature is lowered as it is closer to the rotary shaft 20 and the thermal decomposition reaction is less likely to occur, and the amount of the deposit 23 is easier to be peeled as it is closer to the rotary shaft 20. The separated deposit 23 may be diffused into the reaction chamber by the monosilane gas 22 and adhere to the wafer 24 to adversely affect the electronic material and the like formed on the wafer 24. Therefore, the deposit 23 is removed by etching with a mixed solution of hydrofluoric acid and nitric acid.

However, if etching is repeated to remove the deposit 23, microcracks 25 may occur on the surface of the convex ring portion 9C after the deposit 23 is removed, as shown in FIG. Dust 26 is easily generated from the minute cracks 25, and the dust 26 may be diffused into the reaction chamber by the monosilane gas 22 and adhere to the wafer 24. If the dust 26 adheres to the wafer 24 in this manner, it may cause crystal defects in the process of forming the epitaxial growth layer, and the electronic material or the like formed on the wafer 24 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 is an epitaxy in which a thermal decomposition product of a raw material gas is prevented from adhering to a positioning member for positioning a semiconductor wafer holder mounted on a pedestal portion. It is intended to propose a jar growth device.

[0011]

In order to solve such a problem, in the present invention, in an epitaxial growth apparatus for thermally decomposing a source gas 22 to grow a single crystal layer on a semiconductor wafer 24, a reaction chamber 2B is provided. A gas supply means 21 having a raw material gas ejection port 21A at the tip portion of the extending pipe, a tip of the gas supply means 21 projecting from the tip opening portion, and a root portion of the gas supply means 21 is covered following the tip opening portion. A cylindrical member 9A extending to the end, an inner peripheral surface integrally fixed to the tip opening, and an annular pedestal 9B extending in the radial direction of the tubular member 9A from the tip opening, and a surface of the pedestal 9B. A positioning member 9C having an annular projection 9C projecting toward the tip of the gas supply means 21 and positioning the semiconductor wafer holder 10 placed on the pedestal portion 9B, and inside the positioning member 9C. The annular gas flow that blocks the flow path of the raw material gas 22 so that the raw material gas 22 projected from the pedestal portion 9B toward the tip of the gas supply means 21 and ejected from the raw material gas ejection port 21A does not reach the positioning member 9C. Adjustment member 3
1 and are provided.

[0012]

A gas flow adjusting member 31 is arranged between the gas supplying means 21 and the positioning member 9C on the pedestal portion 9B, and the raw material gas 22 ejected from the gas supplying means 21 by the gas flow adjusting member 31. The epitaxial growth apparatus capable of preventing the thermal decomposition product 23 of the raw material gas 22 from adhering to the positioning member 9C by blocking the raw material gas 22 from directly flowing into the positioning member 9C by blocking the flow path of realizable. This eliminates the need to remove the thermal decomposition product 23 adhering to the positioning member 9C, prevents crystal defects due to dust 26 generated from the microcracks 25 due to the etching of the positioning member 9C, and electronic materials formed on the semiconductor wafer 24, etc. It is possible to further prevent the yield reduction.

[0013]

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. 4 are designated by the same reference numerals, numeral 30 indicates a disk holder bearing portion of the epitaxial growth apparatus as a whole, and a gas shield cover 31 is provided with a gas nozzle 21 and a convex ring portion 9C. The monosilane gas 22 ejected from the gas nozzle 21 is disposed between the
Are prevented from directly flowing into the convex ring portion 9C.

The gas shield cover 31 is made of quartz glass,
A convex eaves portion 31B is formed on the outer periphery of the upper portion of the cylindrical cover body 31A so as to integrally project horizontally. Further, the cover body 31A has an upper surface and a lower surface which are parallel to each other, and a central axial hole 32 for inserting the gas nozzle 21 is formed so as to penetrate from the upper surface to the lower surface. Here, the outer diameter and height of the cover body 31A are about 60 [mm] and about 15 [mm], and the inner diameter of the shaft hole 32 is 23 [mm], which is the same as the shaft portion 9A.

As a result, when the gas shield cover 31 is placed on the disk holder 9, as shown in FIG. 2, the outer peripheral surface of the cover body 31A, the outer diameter 72 [mm], and the wall thickness 3-4.
3 to 5 [m] between the inner peripheral surface of the convex ring portion 9C of [mm]
A gap 33 of [m] is formed. Therefore, the heat of the convex ring portion 9C is prevented from being directly transferred to the outer surface of the cover body 31A.

The eaves portion 31B has the same height as the upper surface of the cover body 31A, and the outer peripheral portion has an outer peripheral portion.
It is formed so as to project 6 to 9 mm horizontally from the outer peripheral surface of A and does not exceed the outer peripheral surface of the convex ring portion 9C. Here, the wall thickness and outer diameter of the eaves portion 31B are about 4
[Mm] and 72 [mm].

As a result, when the gas shield cover 31 is placed on the disk holder 9, 3 to 3 are provided between the lower surface of the eaves portion 31B and the upper surface of the convex ring portion 9C having a height of about 7 mm.
A gap 34 of 5 [mm] is formed. Also, the eaves section 31B
A gap is also formed between the outer peripheral portion of and the inner peripheral portion of the susceptor 10. Therefore, the heat of the convex ring portion 9C and the heat of the susceptor 10 are not directly transmitted to the eaves portion 31B.

In the above structure, the gas shielding cover 31
Is disposed with the lower surface of the cover body 31A abutting on the concave portion 9D between the gas nozzle 21 and the convex ring portion 9C on the upper surface of the disk portion 9B of the disk holder 9, and rotates together with the disk holder 9.

When the susceptor 10 is heated by the induction heating coil 7, this heat is transferred from the inner peripheral portion of the susceptor 10 to the convex ring portion 9C and further passes through the lower surface of the gas shielding cover 31 to the upper surface of the gas shielding cover 31. Reach Actually, the temperature of the gas shielding cover 31 is about 950 [°] or less.

As a result, the monosilane gas 22 supplied from the gas nozzle 21 does not thermally decompose on the surface of the gas shielding cover 31 because the temperature of the gas shielding cover 31 is lower than the temperature required for thermal decomposition. Therefore, almost no thermal decomposition product of the monosilane gas 22 adheres to the gas shielding cover 31.

On the other hand, the monosilane gas 22 that has passed the upper surface of the gas shielding cover 31 passes above the convex ring portion 9C and flows toward the wafer 24 disposed on the susceptor 10. As a result, the convex ring portion 9C becomes monosilane gas 22
The gas shielding cover 31 prevents the flow of the gas from directly hitting. Therefore, the deposit 23 of polysilicon hardly adheres to the convex ring portion 9C.

According to the above construction, the gas shielding cover 31 is provided between the gas nozzle 21 and the convex ring portion 9C, and the gas shielding cover 31 blocks the passage of the monosilane gas 22 ejected from the gas nozzle 21. Monosilane gas 22
It is possible to prevent the deposit 23 from adhering to the convex ring portion 9C by preventing the water from directly flowing into the convex ring portion 9C.

This eliminates the need to remove the deposit 23 adhering to the convex ring portion 9C, prevents the crystal defects due to the dust 26 generated from the minute cracks 25 due to the etching of the convex ring portion 9C, and the electrons formed on the wafer 24. It is possible to further prevent reduction in yield of materials and the like. Further, since it is possible to prevent the minute cracks 25 from being generated in the disk holder 9, the life of the disk holder 9 can be extended.

In the above-described embodiment, the case where the gas shield cover 31 has the eaves portion 31B has been described, but the present invention is not limited to this, and the gas shield cover is only the cover body and the height of the cover body is high. Gas nozzle 2
Even when the gas is formed up to the vicinity of the gas ejection hole 21A of No. 1, it is possible to prevent the raw material gas supplied from the gas nozzle 21 from directly flowing into the convex ring portion 9C, thereby depositing on the convex ring portion 9C. It is possible to prevent the object 23 from adhering and obtain the same effect as described above.

Further, in the above embodiment, the eaves portion 3
Although the case where the gap 34 is formed between the 1B and the convex ring portion 9C has been described, the present invention is not limited to this, and the case where the gap 34 is not formed between the eaves portion 31B and the convex ring portion 9C is also described. The raw material gas supplied from the gas nozzle 21 can be prevented from directly flowing into the convex ring portion 9C, and the same effect as described above can be obtained.

Further, in the above embodiment, a gap 3 of 3 to 5 [mm] is provided between the eaves portion 31B and the convex ring portion 9C.
Although the case where 4 is formed has been described, the present invention is not limited to this, and a gap of 5 [mm] or more may be formed.

Further, in the above-mentioned embodiment, the case where the inside of the cover body 31A is not hollow is described.
The present invention is not limited to this, and the heat transmitted from the disk holder 9 is prevented from increasing the temperature of the gas shield cover as much as possible by hollowing out the inside of the cover body or reducing the area of the lower surface of the cover body. Is also good.

Further, in the above embodiment, the case where the monosilane gas is supplied as the raw material gas has been described.
The present invention is not limited to this, and can be applied to an epitaxial growth apparatus using a source gas other than 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 can be widely applied to an epitaxial growth apparatus for heating the susceptor by another method. .

[0031]

As described above, according to the present invention, the gas flow adjusting member is provided between the gas supply means and the positioning member on the pedestal portion, and the gas flow adjusting member allows the gas flow adjusting member to operate more efficiently than the gas supply means. An epitaxial growth apparatus capable of preventing the pyrolysis product of the raw material gas from adhering to the positioning member by blocking the flow path of the jetted raw material gas to prevent the raw material gas from directly flowing into the positioning member. realizable. This eliminates the need to remove the thermal decomposition products adhering to the positioning member, prevents crystal defects due to dust generated from microcracks due to etching of the positioning member, and further prevents the yield of electronic materials etc. formed on semiconductor wafers from decreasing. it can.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a disk holder bearing portion having a gas shield cover according to an embodiment of an epitaxial growth apparatus according to the present invention.

FIG. 2 is an enlarged cross-sectional view for explaining a positional relationship around a convex ring portion and a gas shield cover.

FIG. 3 is a cross-sectional view for explaining an epitaxial growth device.

FIG. 4 is a cross-sectional view for explaining a usage state of a conventional disk holder.

FIG. 5 is a cross-sectional view used to explain a state in which deposits are attached to the convex ring portion.

FIG. 6 is a cross-sectional view for explaining a minute crack 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, 32 ... Shaft hole, 6 ... Work coil cover, 7 ... High frequency induction heating coil, 8 ...
Rotating shaft, 9 ... Disk holder, 9A ... Shaft, 9B ...
... disk part, 9C ... convex ring part, 9D ... concave part, 1
0 ... Susceptor, 20 ... Rotating shaft, 21 ... Gas nozzle, 21A ... Gas ejection hole, 22 ... Monosilane gas,
23 ... sediment, 24 ... wafer, 25 ... microcracks,
26 ... dust, 30 ... disk holder bearing portion,
31 ... Gas shield cover, 31A ... Cover body, 31
B ... Eaves, 33, 34 ... Gap.

Claims (3)

[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 an annular pedestal portion extending in the radial direction of the tubular member from the tip opening, and an annular projection protruding from the surface of the pedestal portion in the tip direction of the gas supply means. A positioning member for positioning the semiconductor wafer holder mounted on the substrate, a positioning member positioned inside the positioning member, protruding from the pedestal portion toward the tip of the gas supply means, and ejected from the raw material gas ejection port. The epitaxial growth apparatus in which the raw material gas, characterized in that it comprises an annular gas flow adjusting member blocks the flow path of the raw material gas so as not to reach to the positioning member. 2. The epitaxial growth apparatus according to claim 1, wherein the gas flow adjusting member has an overhanging portion that overhangs the positioning member and covers the positioning member. 3. The epitaxial growth apparatus according to claim 1, wherein the projecting portion has a gap between the positioning member and the semiconductor wafer holder at a predetermined distance.