JPH0878350A - Semiconductor heat-treatment apparatus - Google Patents

Abstract

PURPOSE: To obtain a semiconductor heat-treatment apparatus by which the temperature difference between the central part and the peripheral part of wafers is compensated by sheetlike heat-conducting members and by which the temperature distribution inside the face of the wafers is made uniform by a method wherein the wafers and the heat-conducting members are alternately fitted into, and loaded on, slits formed in rods for a boat arranged inside a reaction chamber. CONSTITUTION: A boat 13 is arranged inside a reaction chamber 10, and slits 20 are nicked at equal intervals in rods 19 for the boat 13. Wafers 12 and sheetlike heat-conducting members 17 are supported by the slits mutually parallel and alternately. The heat-conducting members are subjected to the thermal radiation of a heating heater 14 when a temperature is raised, heat which is absorbed due to the thermal radiation is transmitted to the central part of the wafers 12, the heat is absorbed from the central part of the wafers 12 when the temperature is lowered, and the heat is radiated to the circumference of the wafers 12. Thereby, the temperature distribution inside the face of the wafers 12 is made uniform in a heat treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment apparatus for heat treating semiconductor wafers, glass substrates and the like.

[0002]

2. Description of the Related Art Conventionally, various heat treatment apparatuses have been used to form a diffusion layer, a silicon oxide film, a silicon nitride film, etc. on a semiconductor wafer (hereinafter referred to as a wafer) or a glass substrate by heat treatment. . These devices are housed in the reaction chamber, heat the boat 13 (see FIG. 7) on which the wafer 12 is mounted, and introduce an inert gas or a reactive gas (both are collectively referred to as gas) into the reaction chamber. By doing so, a predetermined heat treatment is performed.

The performance required as a heat treatment apparatus is as follows: (1) The resistance and depth of the diffusion layer to be formed, the film thickness of the silicon oxide film, the silicon nitride film, etc. are uniform within the wafer surface and between the wafers, and High reproducibility. (2) Slip does not occur on the wafer due to thermal strain due to temperature difference. (3) A large number of wafers can be processed per operation. (4) The processing time per operation is short. (5) Air is mixed in at the same time when the wafer is taken in and out of the reaction chamber, and an oxide film does not grow on the wafer surface due to the air. Etc.

[0004] Conventionally, as compared with the semiconductor integrated circuit, 1000
In the process of heat treatment such as oxidation at a high temperature near ℃, a heat insulating material is provided around the heater to improve the temperature uniformity,
A soaking tube made of silicon carbide or the like is provided between the heater and the process tube. When performing high-temperature heat treatment using such a semiconductor heat treatment apparatus, air is simultaneously mixed in when a wafer is taken in and out of the reaction chamber, and an oxide film is formed in an uncontrolled atmosphere, which is formed by high-temperature heat treatment. The uniformity of the film or the diffusion layer may be deteriorated, or the quality of the film may be deteriorated. To prevent these, lower the temperature when inserting the wafer into the reaction chamber, drive out the mixed air with a high-purity gas such as nitrogen, argon, or oxygen, and then raise the temperature, and after the heat treatment, after lowering the temperature. The method of taking out is taken. Therefore, if a heat treatment device with a large heat capacity of the heating source is used, it takes time to raise and lower the temperature before and after the oxidation and heat treatment at a desired temperature, resulting in lower productivity and keeping the depth of the impurity diffusion layer shallow. There are problems such as not being able to. In addition, if the wafer is rapidly taken out from the container and subjected to cooling after being subjected to oxidation or heat treatment, there is a problem that a large temperature difference occurs in the wafer surface and slip occurs. This is often due to the radial temperature difference within the wafer surface.

In addition, when a plurality of wafers are installed vertically to the heater, if the heating rate of the heater is increased in order to raise the temperature rise, the heating will in principle cause heat rays radiated from the heater. It is done by absorbing the wafer,
Since multiple wafers placed in parallel with each other cast shadows on each other, the temperature difference around the wafer becomes faster than that at the center when the temperature is raised or lowered, and it is difficult to make the temperature distribution in the radial direction of the wafer uniform. It was This state is shown in FIG. 12
Is a wafer, and 14 is a heater, and for a wafer having a radius r, an area C of an effective heater that heats a portion x away from the center is shown. When observed in a cross-section, only an area in a fixed direction above and below the intersection R between the line extending in the plane direction of the wafer 12 and the side surface of the heater 14 acts as an effective area of the heater. This region becomes narrower toward the center and wider toward the periphery. This is the cause of the non-uniformity of the temperature distribution in the radial direction of the wafer, that is, the heat-treated medium.

As described above, in order to heat-treat a large number of wafers at once (batch processing), it is desirable to install the wafers in the reaction chamber perpendicular to the heater and parallel to each other. However, when the temperature of the wafer is suddenly increased or decreased, and when loading / unloading (wafer loading / unloading) is performed, a temperature difference occurs in the radial direction of the wafer, and slip or crystal defects occur due to thermal strain. there were. Further, especially for an 8-inch wafer or more, a large temperature distribution is generated in the wafer surface, so that it has been impossible to increase the temperature raising / lowering rate too much.

[0007]

As described above, the conventional heat treatment apparatus has a problem that the in-plane temperature distribution of the wafer becomes nonuniform when the temperature of the heater is raised or lowered. It is an object of the present invention to provide a heat treatment apparatus capable of eliminating the above-mentioned drawbacks and making the in-plane temperature distribution of a wafer uniform.

[0008]

In order to achieve the above object, in the first invention, a reaction chamber into which a predetermined gas is introduced,
A heater installed around the reaction chamber and capable of raising and lowering the temperature, a jig having a rod with a recess formed therein, and the rod being an end portion of a plurality of substrates to be heat-treated arranged in the reaction chamber. For supporting in parallel with each other by placing them in the recess, and further inserted between a plurality of the substrates to be heat-treated to receive the heat radiation of the heater at the time of temperature rise and to be absorbed by this heat radiation. In the heat treatment apparatus, there is provided a heat conducting member for transmitting the generated heat to the central portion of the heat treated substrate, absorbing the heat from the central portion of the heat treated substrate when the temperature is lowered, and radiating the heat to the periphery of the heat treated substrate. A plate-shaped semiconductor heat treatment apparatus is mounted on the recess.

[0009]

When the means provided by the present invention is used, the heat conducting member receives the heat radiation of the heater when the temperature rises and transfers the heat absorbed by the heat radiation to the central portion of the heat-treated substrate. Therefore, the temperature difference between the central portion and the peripheral portion of the heat-treated substrate is compensated, and the central portion is heated similarly to the peripheral portion. When the temperature is lowered, the heat conducting member absorbs heat from the heat-treated substrate and radiates it around the heat-treated substrate. Therefore, the temperature difference between the central portion and the peripheral portion is compensated, and the central portion is cooled in the same manner as the peripheral portion. Therefore, the in-plane uniformity of the temperature of the substrate to be heat-treated is maintained during the temperature rise and fall.

[0010]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view of the overall structure of a heat treatment apparatus using the present invention. This heat treatment apparatus has a reaction chamber 1 into which a predetermined gas is introduced.
A vertical cylindrical reaction tube 11 for partitioning 0 and this reaction chamber 1
A heater (14) installed around 0 and capable of raising and lowering temperature, and a jig (boat) for supporting a plurality of substrates (wafers) 12 to be heat-treated arranged in the reaction chamber 10 in parallel to each other.
13 and a plurality of wafers 12, which receives the heat radiation of the heater 14 at the time of temperature rise and transfers the heat absorbed by the heat radiation to the central portion of the wafer 12, and the heat from the central portion of the wafer 12 at the time of temperature reduction. And a heat conducting member 17 that absorbs heat and radiates heat to the periphery of the wafer 12. Further, in this heat treatment apparatus, an inert gas introduction pipe 15 such as argon and nitrogen and an exhaust pipe 16 for exhausting gas inside the reaction chamber 10 are provided.
Is connected.

FIG. 2 is a perspective view showing details of the boat 13, the wafer 12 and the heat conducting member 17. The boat 13 includes an upper surface portion 18, a lower surface portion (not shown), and a rod 19 connecting the both. Slit 20 on rod 19
Are equally spaced, and the slits 20 support the wafer 12 and the heat conducting member 17 in parallel with each other and alternately. These heat conducting members 17 are made of silicon carbide (Si
Formed by C). SiC is a “black body” or a “grey body” in terms of heat radiation, and has very high heat radiation / absorption efficiency. Therefore, it is suitable for the present invention.

FIG. 3 is a sectional view of the boat on which the wafer 12 and the heat conducting member 17 are mounted. The wafer 12 and the heat conducting member 17 are mounted on the boat by fitting their ends into the slits 20 formed in the rod 19. Further, the wafers 12 and the heat conducting members 17 are mounted alternately. The heat conducting member 17 efficiently absorbs heat from a heater (not shown) and gives the heat to the wafer 12 by heat radiation. Further, since the heat conducting member 17 has a very high absorption efficiency, the in-plane temperature distribution is uniform, and the wafer 12 has a uniform in-plane temperature distribution when the temperature of the wafer 12 is raised and lowered. The number of wafers 12 by the batch process is reduced by mounting the heat conducting member 17, but the wafer interval is narrower than that of the method of increasing the wafer interval to make the in-plane temperature distribution of the wafer 12 uniform. It is possible to increase the number of mounted.

FIG. 4 is a sectional view of the boat on which the wafer 12 and the heat conducting member 17 are mounted. The difference from FIG. 3 is the shape of the slit 20. One of the reasons why the in-plane temperature distribution of the wafer is not uniform is the heat conduction from the slit 20 formed in the rod 19. Wafer 12 and rod 19
And the slit 20 are in contact with each other, and if the contact area is large, the temperature in the vicinity of the slit 20 of the wafer 12 causes nonuniformity of the in-plane temperature distribution. Therefore, as shown in FIG. 4, the slit has an acute angle point, and the wafer 12 is supported by this acute angle point to reduce the contact area and minimize the heat conduction from the rod 19.

FIG. 5 is a perspective view of the boat 13, the wafer 12 and the arm 21 which are integrated with the heat conducting member 17.
The arm 21 is a device for mounting the wafer 12 on the boat 13. In the above-described embodiment, the wafer 12 is mounted at a certain distance from the heat conducting member 17, but in the present embodiment, the wafer 12 is mounted on the heat conducting member 17 and has a surface contact state. The heat conducting member 17 has a shape in which a cylinder is projected on the surface portion thereof. When the wafer 12 is transferred to the boat 13, the wafer 12 is transferred and mounted on the cylinder by the arm 21.

FIG. 6 is a cross-sectional view of the boat 12 and the wafer 12 integrated with the heat conducting member 17, and is a cross-sectional view of the boat of FIG. The heat conducting member 17 is specifically integrated with the rod 19. Since the contact between the wafer 12 and the heat conducting member 17 is surface contact, the characteristics of the in-plane temperature distribution of the heat conducting member 17 are easily reflected on the wafer 12, and the in-plane temperature distribution of the wafer 12 becomes uniform.

[0016]

As described above, by using the present invention, it is possible to provide a semiconductor heat treatment apparatus capable of making the in-plane temperature distribution of a wafer uniform during heat treatment.

[Brief description of drawings]

FIG. 1 is an overall configuration cross-sectional view of a heat treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view of a boat on which a wafer and a heat conductive member according to an embodiment of the present invention are mounted.

FIG. 3 is a cross-sectional view of a boat on which a wafer and a heat conductive member according to an embodiment of the present invention are mounted.

FIG. 4 is a cross-sectional view of a boat on which a wafer and a heat conductive member according to an embodiment of the present invention are mounted.

FIG. 5 is a perspective view illustrating a boat and an arm on which a heat conductive member integrated with a rod and a wafer are mounted according to an embodiment of the present invention.

FIG. 6 is a cross-sectional view of a boat on which a heat conductive member integrated with a rod and a wafer are mounted according to an embodiment of the present invention.

FIG. 7 is a perspective view of a boat on which a wafer showing a conventional example is mounted.

FIG. 8 is a diagram showing non-uniformity of wafer in-plane temperature.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Reaction chamber 11 Reaction tube 12 Wafer 13 Boat 14 Heater heater 15 Introducing tube 16 Discharge pipe 17 Heat conduction member 18 Top surface part 19 Rod 20 Slit 21 Arm 22 Wafer lifting table 23 Ring 24 Wafer lifting rod

Claims (4)

[Claims] 1. A reaction chamber into which a predetermined gas is introduced, a heater installed around the reaction chamber for raising and lowering the temperature, a jig having a rod having a recess, and the rod. Is for supporting the ends of the plurality of substrates to be heat-treated arranged in the reaction chamber in parallel with each other by placing them in the recesses. When the temperature is high, the heat radiation of the heating heater is received and the heat absorbed by the heat radiation is transferred to the central portion of the heat-treated substrate, and when the temperature is lowered, the heat is absorbed from the central portion of the heat-treated substrate, and around the heat-treated substrate. A heat treatment apparatus comprising a heat conducting member for radiating, wherein the heat conducting member has a plate shape and is placed in the recess. 2. The semiconductor heat treatment apparatus according to claim 1, wherein the contact between the substrate to be heat treated and the recess of the heat conducting member is point contact. 3. The semiconductor heat treatment apparatus according to claim 1, wherein the heat conducting member is integrally formed with the rod. 4. The semiconductor heat treatment apparatus according to claim 1, wherein a peripheral portion of the heat conducting member is formed thinner than a central portion thereof.