JPH0760803B2 - Method for manufacturing semiconductor wafer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a semiconductor wafer, in which a compound semiconductor having a heterogeneous crystal structure is epitaxially grown on a Si substrate.

[Prior Art] Epitaxial growth of a compound semiconductor such as GaAs on a Si substrate is performed by using metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE).

However, these are all epitaxially grown on one main surface of the Si substrate. However, since the compound semiconductors such as Si and GaAs have different thermal expansion coefficients, there is a problem that the epitaxial wafer is warped or cracked. These cracks and, of course, some warpage became an important obstacle in the device manufacturing process, and an urgent solution was required.

Therefore, one end of the Si substrate is supported in the reaction furnace, and the source gas is supplied into the reaction furnace while uniformly heating both main surfaces of the Si substrate, and at least one or more compound semiconductor layers of the same thickness and the same material are provided. There has been proposed a method for manufacturing a semiconductor wafer in which the Si is simultaneously epitaxially grown on both main surfaces of the Si substrate (for example, Japanese Patent Laid-Open No. 62-101024).

FIG. 1 is an explanatory view showing a semiconductor wafer in which compound semiconductor layers are formed on both main surfaces of a Si substrate, and the compound semiconductor layers 3 of the same thickness and the same material are formed on the two mirror-finished main surfaces of the Si substrate 2. 3 For example, an epitaxial growth layer of GaAs, GaAsP, GaAlAs or the like is formed. Since the compound semiconductor layers 3 and 3 are simultaneously grown on both main surfaces of the Si substrate 2 by the manufacturing method described below, even if the Si substrate 2 and the compound semiconductor layers 3 and 3 have different thermal expansion coefficients. These mutual expansions and contractions do not cancel each other, so that the semiconductor wafer 1 does not warp or cracks occur. Note that the compound semiconductor layers 3 and 3 may be a plurality of layers, but the same layers grown at the same time must always have the same thickness and the same material.

Next, a conventional method for manufacturing a semiconductor wafer will be described with reference to FIG.

FIG. 2 is an explanatory view showing horizontal vapor deposition for carrying out a conventional semiconductor wafer manufacturing method.

One end of the Si substrate 2 is fixed to the wafer support 4 and set in the reaction tube 5. Both main surfaces of the Si substrate 2 are uniformly heated by the infrared lamps 6 and 6 and the gas introduction port 5 of the reaction tube 5 is heated.
When the source gas of the compound semiconductor to be grown from a is supplied, the source gas flows in the same amount on both main surfaces of the Si substrate 2 (upper side and lower side in the drawing), whereby the compound semiconductor epitaxial growth layer 3 having the same thickness, 3 is formed on the Si substrate 2. The exhaust gas is discharged from the exhaust port 5b. The arrows in the figure indicate the flow of gas. Since the semiconductor wafer 1 thus obtained has the compound semiconductor epitaxial layers 3 of the same thickness and the same material grown on both main surfaces of the Si substrate 2 at the same time, warpage and cracks do not occur.

However, in the conventional horizontal vapor phase epitaxy apparatus, one at a time
The growth was limited to one or several sheets.

[Object of the Invention] An object of the present invention is to solve the above-mentioned problems of the prior art,
It is an object of the present invention to provide a manufacturing method capable of mass-producing semiconductor wafers in which cracks and warpage do not occur even when a compound semiconductor is epitaxially grown on a Si substrate.

[Summary of the Invention] The gist of the present invention is to heat at least both main surfaces of a Si substrate supported in a reaction tube while bringing the source gas supplied into the reaction tube into contact with the both main surfaces, and at least one layer In a method of manufacturing a semiconductor wafer in which a compound semiconductor layer of a material is epitaxially grown on both main surfaces of the Si substrate at the same time, inside a reaction tube having a raw material gas inlet at an upper portion and a plurality of exhaust outlets radially extending at a lower portion of a sidewall An inner tube is installed in the chamber to form a gas flow path between the inner tube and the reaction tube, and a plurality of the Si substrates are mounted on a cylindrical wafer support provided in the gas flow path. The surface is supported toward the center of the inner tube, and the flow of the raw material gas supplied from the raw material gas introduction port of the reaction tube is divided into the inner gas flow passage and the outer gas flow passage by the cylindrical wafer support. And the outside gas distribution The exhaust gas that has passed through the passage is directly discharged from the exhaust port, and the exhaust gas that has passed through the inner gas flow passage is discharged from the exhaust port through a hole provided at the bottom of the cylindrical wafer support, and at the same time, the inner pipe A method of manufacturing a semiconductor wafer, comprising heating both main surfaces of the plurality of Si substrates by an inner heating element installed inside and an outer heating element installed so as to surround the outer periphery of the reaction tube. .

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is an explanatory view showing a vertical type vapor phase growth apparatus for carrying out the method for manufacturing a semiconductor wafer of the present invention. FIG. 3 (a) is a front view and FIG. 3 (b) is Fig. 3 (a)
3 is a cross-sectional view taken along line AA in FIG. 3, and FIG. 3C is a cross-sectional view taken along line BB in FIG.

In the figure, 12 is a quartz reaction tube having a gas inlet 12a and an outlet 12c, and 13 is a gas flow passage 12 installed in the reaction tube 12.
An inner tube for forming b, 14 is a wafer support for supporting one end of the Si substrate 2, and 15 and 16 are infrared lamps for uniformly heating both main surfaces of the Si substrate 2. This vertical vapor phase growth apparatus can grow compound semiconductor layers 3, 3 on both main surfaces of a plurality of Si substrates 2 at the same time, so that it can be compared with the conventional horizontal vapor phase growth apparatus described in FIG. And has excellent mass productivity.

The raw material gas of the compound semiconductor to be grown introduced from the gas inlet 12a passes through the gas flow passage 12b, the infrared lamp 15,
Flowing on both main surfaces of the Si substrate 2 heated uniformly by 16
The compound semiconductor produced by the reaction grows to the same thickness on both main surfaces of the Si substrate 2. The gas after the reaction flows through the gaps between the inner tube 13, the wafer support tool 14, and the reaction tube 12, and is discharged through the discharge port 12
Although the gas is discharged from c, the gas flowing between the inner tube 13 and the wafer support 14 is discharged from the hole 14a provided at the bottom of the wafer support 14 to the discharge port 12c. The arrows in the figure indicate the flow of gas. The semiconductor wafer 1 thus obtained is free from warpage and cracks as in the case of using the horizontal vapor phase growth apparatus.

Example 1 Eight Si substrates each having a thickness of 300 μm and whose main surface was 2 ° off from the (100) surface (both main surfaces were mirror surfaces) were used, and Ga (C
_{H 3) 3, Al (CH} 3) 3, Si as AsH _3, n-type dopant gas
Using H ₄ and H ₂ as a carrier gas, n-type GaAlAs was grown to 20 μm on both main surfaces of each Si substrate by the apparatus shown in FIG. The obtained eight semiconductor wafers had no warpage and cracks and had good electrical characteristics.

Example 2 After growing GaAlAs to 20 μm on both main surfaces of eight Si substrates having a thickness of 300 μm by the same method as in Example 1 described above, supply of gases other than H ₂ gas was stopped, and the raw material gas was left. As Ga
(CH ₃ ) ₃ , AsH ₃ , Zn (CH ₂ CH ₃ ) ₂ as P-type dopant gas
Was supplied to grow a p-type GaAs layer to a thickness of 5 μm. Also in this case, warpage and cracks did not occur in the obtained eight semiconductor wafers, and the electrical characteristics were good.

[Effects of the Invention] As described above, the method for manufacturing a semiconductor wafer of the present invention has the following remarkable effects.

(1) Since at least one compound semiconductor layer having the same thickness and the same material can be simultaneously formed on both mirror-finished main surfaces of the Si substrate by epitaxial growth, warpage and cracks do not occur in this semiconductor wafer.

(2) A plurality of semiconductor wafers free from the above-mentioned warpage and cracks can be simultaneously manufactured by one epitaxial growth, and the mass productivity is excellent.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a semiconductor wafer, FIG. 2 is an explanatory diagram showing a conventional example, and FIG. 3 is an explanatory diagram showing one embodiment of a semiconductor wafer manufacturing method of the present invention. 1: semiconductor wafer, 2: Si substrate, 3: compound semiconductor layer.

Claims (1)

[Claims] 1. A heating method for heating both main surfaces of a Si substrate supported in a reaction tube to bring the source gas supplied into the reaction tube into contact with the both main surfaces to form at least one or more compound semiconductor layers of the same material. In the method for manufacturing a semiconductor wafer in which both main surfaces of the Si substrate are epitaxially grown at the same time, an inner tube is provided inside a reaction tube having a source gas introduction port in the upper part and a plurality of exhaust ports extending radially in the lower part of the side wall. A gas flow passage is formed between the inner pipe and the reaction pipe, and a plurality of the Si substrates are provided on a cylindrical wafer support provided in the gas flow passage, one main surface of which is the inner pipe of the inner pipe. While supporting toward the center respectively, the flow of the raw material gas supplied from the raw material gas introduction port of the reaction tube by the cylindrical wafer support is divided into an inner gas flow passage and an outer gas flow passage, and the outer gas flow passage is provided. Exhaust gas that passed Exhausted directly from the exhaust port and passing through the inner gas flow passage, exhaust gas is exhausted from the exhaust port through a hole provided at the bottom of the cylindrical wafer support, and at the same time, the inner side installed inside the inner pipe. A method of manufacturing a semiconductor wafer, comprising heating both main surfaces of the plurality of Si substrates with a heating body and an outer heating body provided so as to surround the outer circumference of the reaction tube.