JP2001196322A - Auxiliary heating plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an auxiliary heating plate which is capable of lessening a temperature difference between the peripheral part and center of a semiconductor wafer so as to uniformly heat the semiconductor wafer, holding it in a light irradiation-type thermal treatment device in which temperature is measured with an optical pyrometer. SOLUTION: An auxiliary heating plate 2 is built in a light irradiation-type thermal treatment device, where the heating plate 2 is formed of ceramic material which is of light transmissivity 0.1% or below to light rays of wavelength 0. 7 to 1.2 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light irradiation type heat treatment apparatus for a substrate, such as a lamp heating apparatus, which rapidly heats a substrate such as a semiconductor wafer by irradiating it with light or an electron beam. The present invention relates to an auxiliary heating plate for reducing a temperature difference in a central portion.

[0002]

2. Description of the Related Art In a light irradiation type heat treatment apparatus for a substrate, a substrate can be rapidly heated to 1100 ° C. or higher in a few seconds by turning on a light source, and can be rapidly cooled by turning off a light source. In a conventional light irradiation type heat treatment apparatus, even when light is uniformly irradiated on a semiconductor wafer, a temperature difference occurs between an outer peripheral portion and a central portion of the semiconductor wafer, and a defect called a slip occurs on the semiconductor wafer. Had been lost.

As a method for preventing a temperature difference between an outer peripheral portion and a central portion so as not to cause the above-mentioned defect, a method using an auxiliary heating plate outside the outer peripheral portion has been disclosed. JP-B-62-44848 and JP-B-63-31
In the publication No. 096, an annular thin plate made of a metal material such as Mo, Ta, or W is disposed as an auxiliary heating plate that receives light irradiation to heat itself, surrounding the semiconductor wafer, and auxiliary heating of the outer peripheral portion of the semiconductor wafer. It is described that the temperature difference is eliminated by this.

In Japanese Patent Application Laid-Open No. 9-22879,
It is disclosed that SiC is used as the auxiliary heating plate and that the structure of the portion of the auxiliary heating plate that supports the semiconductor wafer is a thin plate-shaped projection. This is because if the material of the auxiliary heating plate is the above-mentioned metal material, it reacts with a semiconductor wafer such as a Si wafer, so that the support portion has to be formed into a nail shape, or the substrate is cleaned at the time of cleaning. By using ceramics, the point that reacts with halogen or the like of the material is eliminated by using a ceramic so that the reaction with the semiconductor wafer and the cleaning material is eliminated, and the protrusion can be firmly held by a thin plate-like projection instead of a nail-like projection.

[0005]

Recently, a system has been developed in which the temperature of a semiconductor wafer is individually measured at the outer peripheral portion and the central portion, and the light heating is independently controlled in the circumferential direction accordingly. Instead of measuring the temperature at the position of the conventional auxiliary heating plate or near the semiconductor wafer with a thermocouple, the outer peripheral portion and the central portion are each measured with an optical thermometer. For this reason, the auxiliary heating plate is required to have thermal shock resistance and thermal conductivity higher than those of the conventional material, and to have a light-shielding property in order to measure the temperature with an optical thermometer.

Accordingly, the present invention is directed to a light irradiation type heat treatment apparatus for measuring the temperature of a semiconductor wafer by an optical thermometer. It is an object of the present invention to provide an auxiliary heating plate for retaining the temperature.

[0007]

SUMMARY OF THE INVENTION The present invention relates to an auxiliary heating plate incorporated in a light irradiation type heat treatment apparatus, wherein
An auxiliary heating plate comprising a ceramic material having a light transmittance of 0.1 or less in a wavelength region of 1.2 μm. Further, the thermal conductivity of the ceramic material is
It is preferably at least 50 W / m · K. Further, it is desirable that the ceramic material has a thermal shock resistance that does not cause a crack in a test piece having a diameter of 100 mm and a thickness of 2 mm up to 1000 ° C. at a rate of 100 ° C./sec. Further, it is preferable that the ceramic material contains aluminum nitride (AlN) as a main component.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details will be described below with reference to embodiments. The embodiment of the invention is not limited to the present embodiment. FIG. 1 shows a schematic configuration of a light irradiation type heat treatment apparatus for a semiconductor wafer. The semiconductor wafer 1 is supported by an auxiliary heating plate 2, which is supported by a susceptor 3 made of quartz. Infrared lamp 4 for heating the semiconductor wafer
And is irradiated through the quartz window 5. For the temperature measurement, a radiation thermometer 6 for 900 nm is used, and the temperature is measured through the susceptor 3 made of quartz. The portion between the quartz window and the wafer serves as a flow path for a reaction gas and a cleaning gas, and also allows a wafer transfer loader to pass therethrough.

The infrared lamps 4 can be controlled individually or for each group. Based on data measured by the radiation thermometer 6 corresponding to the irradiation position, the infrared lamps 4 can be controlled at the outer peripheral portion and the central portion of the semiconductor wafer 1. Control the temperature to be uniform. Even if the semiconductor wafer 1 is uniformly heated by the infrared lamp 4, the temperature of the semiconductor wafer 1 drops because the heat escapes at the portion supporting itself. Therefore, the auxiliary heating plate 2 supporting the semiconductor wafer 1 is also irradiated with light and heated, thereby preventing heat dissipation from the supporting portion of the semiconductor wafer. Therefore, it is desired that the auxiliary heating plate has high thermal conductivity. JIS (R16
In the measurement by the laser flash method based on 11), the thermal conductivity is 50 W / m · K or more, preferably 80 W / m · K.
/ M · K or more is preferred.

[0010] Further, it is desired that the auxiliary heating plate has high light absorption in the infrared region in order to increase the efficiency of light irradiation heating, and it is desirable that almost no light is transmitted since an optical thermometer is used. It is. The light transmittance in the wavelength range of 0.7 to 1.2 μm is preferably 0.1% or less, and more preferably 0.05% or less.

[0011] Further, from the demand for speeding up the semiconductor manufacturing process, it is desired that the temperature can be raised and lowered at a high speed.
Therefore, it is desired that the auxiliary heating plate has high thermal shock resistance. In the process of raising the temperature to 1000 ° C., holding for 5 minutes, and lowering the temperature, a test piece with a diameter of 100 mm
It is suitable not to crack at a temperature rising / falling rate of 0 ° C./sec, preferably not to crack at a temperature rising / falling rate of 150 ° C./sec.

Further, a component system which does not react with a reaction gas, a cleaning liquid or a cleaning gas used in a semiconductor manufacturing process is desired. In general, alumina and chemical vapor deposited silicon carbide (CVD-SiC) are often used, but the former has a low thermal conductivity of 10 W / m · K, and the latter is disclosed in
No. 2,879, column 6, lines 4-8,
Light blocking rate is not high. The inventors measured 7 at 900 nm.
-20% transmission.

When the black AlN developed by the inventors was applied, the thermal conductivity was 98 W / m · K, and the light transmittance at 900 nm was 0.07%. The black AlN is Al
N, alumina and silicon oxide in a mass ratio of 98.9: 1: 0.
The raw material powder mixed in 1 was fired at 1750 ° C. and 40 MPa for 2 hours in nitrogen under hot press. In addition, a sintered body obtained by hot pressing only AlN powder, a mixed powder of AlN, alumina, and yttrium oxide, and a mixed powder of AlN, alumina, and silicon nitride also showed suitable characteristics. That is, a material containing AlN as a main component and additional elements added is suitable. Preferably, AlN
A material to which alumina is added is more preferable because the degree of blackness is high and the light transmittance is lower.

The black AlN was processed into 100 mmφ × 2 mmt, and the temperature was raised and lowered to 1000 ° C. at 100 ° C./sec.
No cracking occurred. On the other hand, when a material obtained by attaching silicon carbide to a silicon carbide sintered body by chemical vapor deposition was processed in the same manner, the material did not crack at 70 ° C./sec, but cracked at a temperature rise / fall rate of 100 ° C./sec.

[0015]

According to the present invention, a light irradiation type heat treatment apparatus capable of uniformly and rapidly heating a semiconductor wafer without unevenness in temperature distribution can be constituted.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an apparatus using an auxiliary heating plate of the present invention.

FIG. 2 is a plan view of the auxiliary heating plate of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Si wafer 2 Auxiliary heating plate 3 Quartz susceptor 4 Infrared lamp 5 Quartz window 6 Radiation thermometer

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission Date] January 20, 2000 (2000.1.2
0)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

[0007]

SUMMARY OF THE INVENTION The present invention relates to an auxiliary heating plate incorporated in a light irradiation type heat treatment apparatus, wherein
An auxiliary heating plate comprising a ceramic material having a light transmittance of 0.1 % or less in a wavelength region of 1.2 μm. Further, the thermal conductivity of the ceramic material is preferably 50 W / m · K or more. Also,
The ceramic material desirably has a thermal shock resistance such that it does not crack on a test piece having a diameter of 100 mmφ and a thickness of 2 mm up to 1000 ° C. at a rate of 100 ° C./sec. Further, the ceramic material is aluminum nitride (Al
Preferably, N) is the main component.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

When the black AlN developed by the inventors was applied, the thermal conductivity was 98 W / m · K, and the light transmittance at 900 nm was 0.07%. The black AlN is Al
N, alumina and silicon oxide in a mass ratio of 98.9: 1: 0.
The raw material powder mixed in 1 was obtained by hot press firing in nitrogen at 1750 ° C. and 40 MPa for 2 hours. In addition, a sintered body obtained by hot pressing only AlN powder, a mixed powder of AlN, alumina, and yttrium oxide, and a mixed powder of AlN, alumina, and silicon nitride also showed suitable characteristics. That is, a material containing AlN as a main component and additional elements added is suitable. Preferably, AlN
A material to which alumina is added is more preferable because the degree of blackness is high and the light transmittance is lower.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/26 G

Claims (4)

[Claims] 1. An auxiliary heating plate incorporated in a light irradiation type heat treatment apparatus, wherein a ceramic material having a light transmittance of 0.1 or less in a wavelength range of 0.7 to 1.2 μm is used. And auxiliary heating plate. 2. The thermal conductivity of the ceramic material is 50.
2. The auxiliary heating plate according to claim 1, which has a W / mK or more. 3. The ceramic material has a diameter of 100 mm.
2. A test piece having a φ thickness of 2 mm having a thermal shock resistance that does not crack at a temperature rise / fall of 100 ° C./sec up to 1000 ° C.
Or the auxiliary heating plate according to 2. 4. The auxiliary heating plate according to claim 1, wherein the ceramic material contains aluminum nitride as a main component.