JPS62163323A - Infrared heater - Google Patents

Abstract

PURPOSE:To control a temperature precisely with excellent response without being affected by an outside air temperature by vacuum-sealing a temperature detecting section for a thermocouple into a tube and isolating the temperature detecting section from outside atmospheric air. CONSTITUTION:Nitrogen gas fed from a gas supply port 11 is discharged from a gas exhaust port 12. Semiconductor substrates 13 are heated by an infrared-ray lamp 15. A temperature is controlled to a fixed temperature by a thermocouple 17 in an silica reaction vessel 10. A temperature detecting section 17a for the thermocouple 17 excellently receives the heating temperatures of the semiconductor substrates 13 in the silica reaction vessel 10 through an infrared transmitting protective tube 19 and carbon 18 coated with silicon carbide easy to absorb infrared rays at that time. Since the temperature detecting section 17a is sealed in a vacuum, the heat of the carbon 18, which is coated with silicon carbide and coats the temperature detecting section 17a for the thermocouple 17, is discharged to the outside only by heat radiation, and heat exchange with the outside atmosphere of the silica reaction vessel 10 can be ignored approximately. Accordingly, the temperature of the temperature detecting section 17a is brought to a temperature extremely close to the temperatures of the semiconductor substrates 13.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an infrared heating device, and particularly to an infrared heating device for silicon (Si) wafers used in annealing processes, vapor phase growth processes, etc. in the semiconductor industry.

Prior Art Conventional heating devices employ a method of heating with an electric furnace. When this method is performed in the atmosphere, rapid heating and cooling can be achieved by heating the container to the desired temperature with the lid open and loading and unloading semiconductor wafers. However, there is a problem in that the wafer oxidizes when exposed to the atmosphere, and heating and cooling must be performed in a gas atmosphere to avoid contact of the wafer with air. However, because a normal electric furnace has a large heat capacity, there is a problem that rapid heating and rapid cooling cannot be performed in a gas atmosphere. Therefore, in recent years, infrared heating devices that enable rapid heating and rapid cooling by reducing the heat capacity of the device itself have been attracting attention. do.

FIG. 3 shows a conventional infrared heating device. Third
In the figure, 1 is a quartz reaction vessel, which has a gas supply port 4 and a gas discharge port 5 on the left and right sides, and has a semiconductor substrate 3 inside.
A susceptor 2 is provided to hold the susceptor 2. An infrared lamp 6 is provided above the reaction vessel 1 to heat the inside of the reaction vessel 1 by radiation. Further, a thermocouple 7 is provided inside the reaction vessel 1 from the outside, and a temperature detection portion covered with a substance 8 that easily absorbs infrared rays is located near the suspenner 2.

For example, nitrogen gas is supplied into the reaction vessel 1 from a gas supply port 4 according to the intended heating process, and is discharged from a gas discharge port 5. In this state, the semiconductor substrate 3 in the reaction vessel 1 is radiantly heated by the infrared lamp 6 to a predetermined temperature, for example, about 1000°C. The temperature is controlled by a thermocouple 7 in the quartz reaction vessel 1 so that the semiconductor substrate 3 reaches a predetermined temperature.

However, in the above configuration, since the thermocouple 7 is exposed inside the quartz reaction vessel 1, when the temperature is raised to high temperature or under reduced pressure such as in vapor phase growth, the thermocouple 7 is exposed to the inside of the quartz reaction vessel 1. 1. Impurities fly out into the interior. Therefore, the semiconductor substrate 3 placed in the quartz reaction vessel 1 is contaminated.

As shown in FIG. 4, an infrared heating device that solves this problem can be constructed by inserting a thermocouple 7 into a quartz glass protective tube 9 to control the temperature (for example, patented Publication No. 57-45054) has already been proposed.

Problems to be Solved by the Invention However, in the above configuration, the thermocouple 7 is completely enclosed within the quartz reaction vessel 1 by a protective tube 9 made of quartz glass, and is not exposed inside the quartz reaction vessel 1. Although not, since the inside of the protective tube 9 communicates with the outside of the quartz reaction vessel 1, the thermocouple 7 is in contact with the outside atmosphere. In other words, the temperature of the thermocouple 7 increases when it receives heat radiation from the infrared lamp 6, but since it is in direct contact with the outside air, the temperature is lower than that of the semiconductor substrate 3 due to heat conduction and transfer to the outside atmosphere. The value will vary depending on the outside temperature.Furthermore, for the same reason, the responsiveness of the temperature rise of the thermocouple 7 will be worse than the temperature rise rate of the semiconductor substrate 3.Therefore, the temperature control ( The problem was that reproducibility was poor.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a container at least partially transparent to infrared rays, and an infrared generation source located outside the container for radiant heating of the inside of the container. , an infrared heating device comprising: a base located inside the container on which a semiconductor substrate is placed; and a thermocouple located near the semiconductor substrate to detect the temperature of the semiconductor substrate.
Detection B in which the temperature detection part is coated with a material that easily absorbs infrared rays or a material that is easy to detect temperature, such as the same material as the semiconductor substrate.
1' is vacuum sealed in the tube.

Function The present invention has the above-described configuration, and the temperature detection part of the thermocouple is in a state in which impurities are prevented from flying out so that the temperature can be easily detected through the tube made of an infrared-transparent substance and the temperature-detectable substance in the container. Since the thermocouple is vacuum-sealed within the tube and isolated from the outside atmosphere, the controllability of the temperature of the thermocouple that receives the radiant heat from the infrared lamp is limited to heat conduction and heat transfer other than the heat radiation of the thermocouple itself. Since there is almost no heat exchange, it is better than when there is heat exchange with the outside air. In other words, it is not affected by the temperature of the outside air, has good responsiveness, and is close to the temperature of the semiconductor substrate, so accurate temperature control is possible.

EXAMPLE Hereinafter, an infrared heating device according to an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a sectional view of an infrared heating device in an embodiment of the present invention.

In the figure, 10 is a quartz reaction vessel, which is provided with a gas supply port 11 on the right side and a gas discharge port 12 on the left side. A susceptor 14 on which a semiconductor substrate 13 is placed is provided within the quartz reaction vessel 10 . An infrared lamp for radiant heating of the semiconductor substrate 13 is provided above the quartz reaction vessel 10, and a reflecting mirror is provided at the back of the infrared lamp 15 to efficiently reflect the irradiated light from the infrared lamp 15 and direct it toward the semiconductor substrate 13. It is provided. Carbon (C
)1 Inside the quartz reaction vessel 10, there is a thermocouple 17 housed in a protective tube 19 made of quartz glass, which is an infrared transparent material.
is inserted from the side, and the temperature detection part 17a of the thermocouple 17 is located near the susceptor 14 and is covered with carbon (C') coated with silicon carbide (SiC), a material that easily absorbs infrared rays. The temperature detecting portion 17a of the thermocouple 17 is also enclosed as a vacuum portion 2o at the tip of the protective tube 19, as seen in FIG.

Nitrogen gas supplied from the gas supply port 11 is discharged from the gas discharge port 12. The semiconductor substrate 13 has a predetermined thickness of about 10
It is heated to 00''C by an infrared lamp 15. The temperature is controlled by a thermocouple 17 in the quartz reaction vessel 10 to a predetermined temperature. In this case, the temperature detection part 17a of the thermocouple 17 receives the heating temperature of the semiconductor substrate 13 in the quartz reaction vessel 1o through an infrared-transparent protection tube 19 and carbon 18 coated with silicon carbide that easily absorbs infrared rays.This temperature detection part 17a is sealed in a vacuum. Therefore, the heat of the carbon 18 coated with silicon carbide that coats the temperature detection part 17a of the thermocouple 17 is only released through thermal radiation, and the quartz reaction vessel 1
o Heat exchange with the outside atmosphere is almost negligible. Therefore, the temperature is very close to that of the semiconductor substrate 13, and furthermore, it is possible to obtain the same level of temperature response as the semiconductor substrate 13, and accurate temperature control is possible.

As described above, according to this embodiment, the protection tube 19 made of quartz glass vacuum-seals the temperature detection part 17a of the thermocouple 17 coated with carbon 18 coated with silicon carbide.
By providing this, it is possible to perform accurate temperature control with good responsiveness.

Note that in this embodiment, the temperature detection section 17 of the thermocouple 17
Although a is coated with carbon 18 coated with silicon carbide, the coating material may be any material that easily absorbs infrared rays, and may be carbon (C) or silicon (Si).

Further, in this embodiment, the quartz reaction vessel 10 and the quartz glass protection tube 19 were used, but they may be made of other materials that transmit infrared rays.

Effects of the Invention According to the present invention, a thermocouple in which at least a portion of the thermocouple is inside an infrared-transparent container and whose temperature detection portion is located near a semiconductor substrate has a tube made of an infrared-transmissive material and a thermocouple that is easy to detect temperature within the container. In the state where impurities are prevented from jumping out, which makes it easy to detect temperature through substances, the temperature detection part is isolated from the outside air by a vacuum inside the tube, so there is almost no escape of heat other than radiant heat to the outside air, and it is highly responsive and Accurate temperature control that is unaffected by air temperature is possible.

[Brief explanation of drawings]

Fig. 1 is a sectional view of an infrared heating device according to an embodiment of the present invention, Fig. 2 is an enlarged view of the tip portion of the thermocouple and quartz glass protection tube shown in Fig. 1, and Fig. 3 is a cross-sectional view of a conventional infrared heating device. 4 is a cross-sectional view of another conventional infrared heating device. 13...Semiconductor substrate, 14...Susceptor, 15...Infrared lamp, 16...
Reflector, 17...Thermocouple, 17a...
Temperature detection part, 18...Silico carbide (SiC)
Carbon coated with (C), 19...
Quartz glass protection tube, 20... Vacuum section. Name of agent: Patent attorney Toshio Nakao and 1 other person f3
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Claims (2)

[Claims] (1) A container at least partially transparent to infrared rays; an infrared generation source located outside the container for radiant heating of the inside of the container; and a base located inside the container on which a semiconductor substrate is placed. , to detect the temperature of the semiconductor substrate,
In the infrared heating device equipped with a thermocouple located near the semiconductor substrate, the temperature detection part is coated with a material that easily absorbs infrared rays or a material that is easy to detect temperature, such as the same material as the semiconductor substrate. An infrared heating device characterized in that the thermocouple is covered with a tube made of an infrared transparent material so as to face the inside of the container, and the temperature detection section is vacuum sealed inside the tube. (2) The infrared heating device according to claim 1, wherein the substance that easily absorbs infrared rays is carbon, silicon carbide, or silicon.