JPH097956A - Electric resistance heater for heat treating semiconductor - Google Patents

Abstract

PURPOSE: To obtain a sufficient strength under using conditions by enhancing the thermal expansion coefficient of a carbon base material higher than that of a silicon carbide film, and setting the thermal expansion coefficient of the base material in a specific range. CONSTITUTION: A hollow cylinder 11 extending upward is mounted at the lower surface of a base 10, and a heater support 12 is mounted at the upper end. A heater 16 is mounted at the support 12 via an insulating rod 13, a reflecting plate 14 and an insulating rod 15. The heater uses isotropic carbon having thermal expansion coefficient of 4.3 to 6.0×10<-6> (20 to 450 deg.C) as a base material. A silicon carbide film is formed on the surface of the base material by a CVD coating method, and the base material is covered with the silicon carbide film. The thermal expansion coefficient of the base material is enhanced higher than that of the silicon carbide film. Thus, a sufficient strength can be obtained under the using conditions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor heat treatment apparatus, and more particularly to a heating element used in an epitaxial growth apparatus.

[0002]

2. Description of the Related Art A conventional vapor phase growth apparatus is disclosed in, for example, Japanese Unexamined Patent Publication No. 5-152207.
The wafer is supported by a wafer holding member and heated by a heating element arranged below the wafer holding member to form a vapor phase growth film on the wafer surface.

In the above vapor phase growth apparatus, a hollow cylindrical body extending upward is attached to the lower surface of the base,
A heating element support is attached to the upper end thereof, and a dish-shaped reflecting plate is arranged above the heating element support, and the heating element is accommodated inside and a soaking plate is attached to the upper end. The upper end of the dish-shaped reflection plate is located above the heat equalizing plate, and a ring-shaped susceptor is fitted on the upper end. A counterbore is formed on the inner peripheral side of the susceptor, and a wafer is placed in this. A reduced pressure atmosphere of 50 to 400 Torr is formed in the reaction chamber, and a large amount of a raw material gas such as dichlorosilane and a carrier gas such as hydrogen are introduced from the gas introduction port to perform vapor phase growth. The wafer temperature is heated to about 1150 ° C.

In the conventional vapor phase growth apparatus as described above, as the heating element, a highly purified carbon material or a material obtained by coating the surface of this carbon material with a silicon carbide film is used.

[0005]

However, also in such a vapor phase growth apparatus, mass productivity is an important issue, and therefore rapid heating and quenching of wafers are accelerated, and wafers to be processed in the manufacturing process. Insertion intervals have been shortened.

Therefore, in the conventional heating element made of carbon coated with a silicon carbide film, the silicon carbide film and the carbon at the time of use are different from each other due to the difference in thermal expansion under the severe conditions of recent rapid heating and quenching. The strength with the substrate has become important.
Since the strength of the silicon carbide film is as low as 50 to 400 MPa and the strength of the carbon base material is as low as 20 to 60 MPa, cracks easily occur in the base material under high temperature and severe use conditions.
We could not secure a sufficient life.

An object of the present invention is to provide an electric resistance heating element for semiconductor heat treatment, which can secure sufficient strength under use conditions.

[0008]

According to the present invention, there is provided a vapor phase growth apparatus for supporting a wafer by a wafer holding member and heating the wafer to form a vapor phase growth film on the wafer surface. The heating element is composed of a carbon base material and a silicon carbide based film provided on the surface of the carbon base material, and the thermal expansion coefficient of the carbon base material is made higher than that of the silicon carbide based film. 4.3 to 6.0 × 10 ⁻⁶ / ° C. (20 ° C. to 45 ° C.)
The gist is an electric resistance heating element for semiconductor heat treatment, which is characterized in that the temperature is 0 ° C.).

Preferably, the silicon carbide film has a complex structure in which α-SiC intersperses in β-SiC crystal grains in a streak pattern.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A heating element according to the present invention is a vapor phase growth method in which a wafer is supported by a wafer holding member, and the heating element placed below the wafer holding member heats the wafer to form a vapor growth film on the wafer surface. Used in equipment. The heating element is a carbon base material,
It is made of a silicon carbide film provided on the surface thereof.

The heating element has a coefficient of thermal expansion of 4.3 to 6.0 ×.
Isotropic carbon having a temperature of 10 ⁻⁶ / ° C. (20 ° C. to 450 ° C.) is used as a base material, and a silicon carbide film is formed on the surface of the carbon base material by a CVD coating method. It is covered with a membrane. The coefficient of thermal expansion of the carbon base material is made higher than the coefficient of thermal expansion of the silicon carbide film. As a result, residual stress remains in the film, and a sufficient life can be secured under high temperature and severe use conditions. The coefficient of thermal expansion of the silicon carbide film of the present invention is 3.8 × 10 ⁻⁶ / ° C. (20 ° C. to 450 ° C.).
° C).

The silicon carbide film is composed of β-SiC and α-SiC.
And a small amount of α-SiC is β-Si
The state is scattered in C. For example, α-Si
C accounts for 0.01 to 5% by volume, preferably about 0.1 to 2% by volume, of the entire silicon carbide film.

FIG. 2 shows an X-ray diffraction spectrum of the silicon carbide film, and most of the powder is β-SiC (shown by white circles), but α-SiC of trace level (shown by black circles). 6H and 15R) have been detected.

FIG. 3 is a scanning transmission electron microscope image showing the crystal structure. The streak black line portion is the α-SiC crystal.

FIG. 4 is a TEM high-resolution image showing the crystal structure. The horizontal stripes are α-SiC crystals.

FIG. 5 is a selected area electron diffraction image showing the crystal structure. The presence of white flowing lines indicates α-SiC crystals.

FIG. 6 is a schematic view of an about 3000 times SiC film.

By adopting such a crystal structure, deformation at high temperature is reduced, erosion resistance is improved, and high temperature stability is improved.

The silicon carbide film is formed by high-purity treatment inside the furnace and by a CVD coating method at a temperature (for example, 1600 to 1900 ° C.) higher than the conventional temperature (for example, about 1300 ° C.).

In the heating element of the present invention, it is desirable that the silicon carbide film has a thickness of 45 to 300 μm.

As described above, the crystalline silicon carbide film formed by the CVD coating method has β-SiC and α-SiC.
It is composed of a special composite structure of 1), and the sublimation of the β-SiC crystal can be suppressed in the non-oxidizing atmosphere at 1400 ° C. or higher, and the life becomes long.

[0022] For the illustrated example of the present invention will illustrated example will be described.

In FIG. 1, a hollow cylindrical body 11 extending upward is attached to the lower surface of the base 10, and a heater support 12 is attached to the upper end thereof. Heater support 1
A heater 16 is attached to 2 via an insulating rod 13, a reflector 14 and an insulating rod 15. The lower end of the hollow cylindrical body 11 is closed by a lid 18, and inside the hollow cylindrical body 11, a power supply wiring 17 penetrating the lid 18 and connected to a heater 16 is provided.

A hollow rotary shaft 20 is provided so as to surround the hollow cylindrical body 11, and the hollow rotary shaft 20 has a bearing 21.
Allows the base 10 to rotate freely regardless of the hollow cylindrical body 11.
Mounted on A pulley 22 is attached to the hollow rotary shaft 20, and is rotated by a belt 23 by a motor (not shown).

The upper end of the hollow rotary shaft 20 extends into a reaction chamber 25 formed above the upper surface of the base 10 by a bell jar 24 showing only a part, and the upper end of the hollow support shaft 27 is made of carbon through a key 26. Is stuck. Support disk 27
A support ring 28 made of quartz glass, carbon, or ceramics is rotatably attached to the support disk 27 integrally with the support disk 27.

The support ring 28 surrounds the outer periphery of the heater support 12, the reflection plate 14 and the heater 16 and extends above the heater 16. A step 29 is formed in the upper part of the inner peripheral surface of the support ring 28, and the heating plate 30 is formed on the step 29.
Is fitted. The heating plate 30 is arranged substantially in parallel with the heater 16 with a space therebetween, and is heated in a non-contact manner with the heater 16.

A step portion 31 is formed on the upper end of the support ring 28, and a ring-shaped wafer holding plate 32 is fitted in the step portion 31, and inside a step portion 33 formed near the inner circumference of the upper surface of the wafer holding plate 32. The wafer W is held on the wafer. The wafer W supported by the wafer holding plate 32 is placed so as to have a predetermined distance C from the heating plate 30 which is preferably 3 mm or more.

A cylindrical heat retaining cylinder 40 is concentrically arranged on the outer periphery of the support ring 28 with a predetermined gap.

Next, the operation of the above vapor phase growth apparatus will be described.

Power is supplied to the heater 16 to heat the heating plate 30, and the hollow rotary shaft 20 is rotated to rotate the heating plate 30, the wafer holding plate 32, and the wafer W. The wafer W and the wafer holding plate 32 are heated by the heating plate 30.

The wafer holding plate 32 supports the wafer W so as to keep the interval C at a predetermined value, and is heated by the heating plate 30 to heat the outer circumference of the wafer W to suppress the temperature decrease of the outer circumference. Has the role of providing a uniform temperature distribution from the center to the outer periphery.

[0032]

When the heater is formed of the special heating element as described above, the following effects can be obtained. That is, the strength of the silicon carbide film formed on the surface of the carbon substrate is remarkable. In particular, the strength of the film is stable under high temperature use conditions, and the shape of the particles is not disturbed. It is particularly effective in the case of a complicated shape such as a spiral shape. Strength is further increased by appropriately selecting the conditions during film formation so that the desired residual stress remains in the silicon carbide film under the conditions of vapor phase growth. Residual stress remains in the film, and a sufficient life can be secured under high temperature and severe use conditions.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is an X-ray intensity spectrum graph showing a state in which α-SiC is scattered in β-SiC.

FIG. 3 is a scanning transmission electron microscope image showing a crystal structure.

FIG. 4 is a TEM high-resolution image showing a crystal structure.

FIG. 5 is a selected area electron diffraction image showing a crystal structure.

FIG. 6 is a schematic view of a SiC film having a magnification of about 3000 times.

[Explanation of symbols]

 10 Base 11 Hollow Cylindrical Body 12 Heater Support 13, 15 Insulating Rod 14 Reflector 16 Heater 17 Power Supply Wiring 18 Lid 20 Hollow Rotating Shaft 21 Bearing 22 Pulley 23 Belt 24 Belger 25 Reaction Chamber 27 Support Disk 28 Support Ring 29 Step Section 30 Heating plate 31, 33 Step portion 32 Wafer holding plate 40 Insulating cylinder W wafer

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[Procedure amendment]

[Submission date] June 30, 1995

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A heating element according to the present invention is a vapor phase growth method in which a wafer is supported by a wafer holding member, and the heating element placed below the wafer holding member heats the wafer to form a vapor growth film on the wafer surface. Used in equipment. The heating element is a carbon base material,
It is made of a silicon carbide film provided on the surface thereof. The coefficient of thermal expansion of the carbon base material is made higher than the coefficient of thermal expansion of the silicon carbide film.
The thermal expansion coefficient of the carbon base material is 4.3 to 6.0 × 10 ⁻⁶ /
C. (20.degree. C. to 450.degree. C.), the coefficient of thermal expansion of the silicon carbide film is preferably 3.8.times.10.sup.- ⁶ / .degree. C. (20.degree. C. to 450.degree. C.).

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

FIG. 6 is a schematic view of a SiC film of about 3,000 times. As is clear from FIGS. 4, 5 and 6, α−
SiC is interspersed linearly in the β-SiC crystal particles.

Claims (3)

[Claims] 1. In a vapor phase growth apparatus for supporting a wafer with a wafer holding member and heating the wafer to form a vapor phase growth film on the wafer surface, a heating element for heating the wafer comprises:
Consisting of a carbon base material and a silicon carbide film provided on its surface,
The thermal expansion coefficient of the carbon base material is made higher than that of the silicon carbide film, and the thermal expansion coefficient of the carbon base material is set to 4.3 to 6.0 × 1.
An electric resistance heating element for semiconductor heat treatment, characterized in that the temperature is set to 0 ^-6 / ° C (20 ° C to 450 ° C). 2. In a vapor phase growth apparatus for supporting a wafer by a wafer holding member and heating the wafer to form a vapor phase growth film on the wafer surface, a heating element for heating the wafer comprises:
Consisting of a carbon base material and a silicon carbide film provided on its surface,
An electrical resistance heating element for semiconductor heat treatment, wherein the silicon carbide film has a complex structure in which α-SiC is interspersed linearly in β-SiC crystal grains. 3. The semiconductor heat treatment according to claim 1, wherein the silicon carbide film is formed on the surface of the carbon base material so that a residual stress of −50 to −400 MPa remains at room temperature. Electric resistance heating element.