JPS6298718A - Vapor growth device - Google Patents

Abstract

PURPOSE:To form the film of good quality having excellent uniformity by a method wherein the center part of a wafer supporting stand is composed of a first member having a low absorption factor for infrared rays, the outer circumference of the wafer supporting stand is composed of a second member having a high absorption factor for infrared rays, and a conveying means with which said wafer-carrying second member is carried to outside a reaction chamber is provided. CONSTITUTION:A wafer supporting stand 19 is composed of the first member 19a made of quartz having the disc-shaped center part and the disc-shaped and SiC-coated member 19b made of graphite surrounding the side of the first member 19a. Also, the center part of the first member 19a is supported by a supporting post 22, and the lower end of the supporting post 22 is coupled to a rotating means 23. A round- shaped and convexed placing stand 30, having the upper part of diameter smaller than the inside diameter of the second member 19b of the wafer supporting stand and two arms 32 to be used as the conveying means with which a wafer 31 is carried between the reaction chamber and the placing stand 30 in the state wherein the wafer is placed on the second member 19b of the wafer supporting stand, are provided on the outside of a reaction chamber 12 at the position opposing to the wafer supporting stand 19 astriding an aperture 29.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a vapor phase growth apparatus employing an infrared heating method, which is widely used in the semiconductor industry.

Conventional vapor phase growth equipment in the semiconductor industry uses heat to separate reactive gas molecules on the surface of a wafer to form a thin film of polycrystalline silicon or the like. The thickness of the film thus formed and the uniformity of resistivity are greatly influenced by the wafer surface temperature. Therefore, in order to obtain a high quality vapor phase grown film, it is necessary to maintain a uniform temperature distribution over the entire surface of the semiconductor substrate.

A conventional vapor phase growth apparatus employing an infrared heating method has a configuration as shown in FIG. 4, as shown in Japanese Patent Publication No. 57-44009, for example.

The reaction chamber can be completely isolated from the outside air by a quartz belljar 1 and a base plate 2, and the base plate 2 has a gas supply port 3 for supplying the reaction gas and a gas exhaust port for discharging the reaction gas. Outlet 4 is installed. Also,
On the base plate 2 is a wafer support stand 6 on which the wafer 6 is placed.
is installed. Also, on the outside of the quartz perjaz,
An infrared lamp 7 for heating the wafer 5 and a reflecting mirror 8 are installed so that reflected light from the infrared lamp 7 can efficiently irradiate the wafer 6.

Problems to be Solved by the Invention However, in the conventional vapor phase growth apparatus configured as described above, the temperature distribution on the surface of the wafer 5 depends on the thermal energy supplied from the infrared lamp 7 and the wafer 5 and wafer support 6. The upper surface of the support base 6 receives a certain amount of radiant heat from the infrared lamp 7, while the outer peripheral surface receives a large amount of heat corresponding to its surface temperature. Heat is released. Therefore, the temperature distribution on the surface of the wafer support 6, that is, on the wafer 5, is high at the center and low at the outer periphery. Furthermore, the temperature of the infrared lamp itself tends to be higher at the center than at the edges. As a result, the thin film grown on the wafer 6 by vapor phase growth has the disadvantage that it is thinner at the edges than at the center. In order to avoid these situations, methods have been taken to control the power applied to each infrared lamp, but this does not solve the problem of uneven temperature distribution in the portions located parallel to each infrared lamp. Furthermore, a method of rotating the wafer support table is considered, but as the diameter of the sea urchin filtrate to be processed becomes larger in the future, it will become difficult to eliminate uneven temperature distribution.

There are still vapor phase growth apparatuses equipped with wafer transfer means to increase processing speed (for example, Japanese Patent Laid-Open No. 59-22292
2) has also been devised, but in this device, as shown in FIG. A recess is provided, which reduces the uniformity of film formation, and also makes it difficult to transfer the wafer if a rotation mechanism is provided on the wafer support. Furthermore, the film naturally adheres not only to the wafer but also to the wafer support, which is at a high temperature. If growth is repeated, the attached film will peel off and fall onto the wafer, causing abnormal growth and contamination. Therefore, after performing multiple growths, it is necessary to take out the wafer support and periodically remove the attached film, and even if the above-mentioned wafer transfer means is provided, this operation greatly reduces the processing speed. It will drop.

Therefore, the present invention provides a vapor phase growth apparatus that can uniformize the temperature on the wafer, form a high quality vapor phase growth film with excellent uniformity, and efficiently transfer the wafer. Means for Solving the Problems In order to solve the above problems, the vapor phase growth apparatus of the present invention includes:
The center of the rotatable wafer support is a first member with a low absorption rate of infrared light, and the outer periphery is a second member with a high absorption rate of infrared light.
The second member has a wafer placed thereon and is provided with means for transporting the second member on which the wafer is placed.

Effect of the Invention According to the above-described structure of the present invention, the infrared light emitted from the infrared lamp is absorbed more in the outer peripheral part of the wafer support, and the temperature is made uniform over the entire surface of the wafer by canceling out the heat released from the outer peripheral part. Since the wafer is transferred while placed on the wafer support, there is no need to lift the wafer from the wafer support, the mechanism is simple, and it is easier to obtain uniformity in the formed film. Furthermore, in order to remove the film attached to the wafer support, this can be done by periodically replacing the wafer support with another wafer support when the wafer support is transferred outside the reaction chamber.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1st
The figure is an external view of a vapor phase growth apparatus in one embodiment of the present invention, and FIG. 2 is a sectional view of a reaction chamber.

In the figure, the reaction chamber 12 is composed of a wall member 21 made of stainless steel and having a water cooling groove 2o therein, and a transparent quartz plate 13 provided on the upper part. This transparent quartz plate 13 is fixed to the wall member 21 via a known gas sealing means such as an O-ring. Reaction chamber 12
A gas supply port 14 connected to a gas supply pipe extending from a gas supply device (not shown) is provided at one end of the side wall, and an exhaust port 15 connected to a vacuum evacuation device such as a rotary pump (not shown) is provided at the other end. A heating block 16 is still attached above the outside of the reaction chamber 12. This heating block 16 has a plurality of horizontal rod-shaped infrared lamps (7 lamps) arranged at equal intervals so as to be perpendicular to the flow direction of the reaction gas flowing from the gas supply port 14 to the gas discharge port 15. The infrared lamp 17 is connected to the gas supply side 2.
Divided into three zones: main, three in the center, and two on the gas exhaust side.
Each is electrically connected to a power adjustment unit (not shown), making it possible to control the temperature in the gas flow direction. Also,
Inside the reaction chamber 12, there is a wafer plate on which a wafer is placed.
A support stand 19 is installed. As shown in FIG. 3, this wafer support stand 19 includes a first member 19a made of quartz and having a disk-shaped center, and a part H1j of this first member 19a.
The second member 19b is made of SiC-coated graphite and has a disc shape surrounding it. Further, the center portion of the first member 19a is supported by a support post 22, and the lower end of the support post 22 is connected to a rotating means 23. Therefore, the wafer support stand 19 is rotated via the support post 22. Further, on the exhaust port side of the reaction chamber, a carrier gas supply port 25 is formed which is connected to the carrier gas supply pipe 24 and has an opening close to the lower surface of the transparent quartz plate 12.

Furthermore, as shown in FIG. 2, the outer periphery of the carrier gas supply port 25 is supported by a protrusion 26 on the side wall of the reaction chamber at a position close to the bottom of the carrier gas supply port 25, and the carrier gas supply port A partition that forms a flow path so that the carrier gas supplied from 25 first flows along the lower surface of the transparent quartz plate 13 as shown by the arrow, then turns around at the gas supply port 14 side and is ejected into the reaction chamber 12. A plate 27 is arranged. The partition plate 27 is made of a material that transmits infrared light, such as transparent quartz. Further, the front side wall of the reaction chamber 12 has an opening 29 equipped with a gate valve 28, and the upper part of the reaction chamber 12 supports a wafer at a position facing the wafer support 19 across the opening 29. A circular convex pedestal 14 3 smaller than the inner diameter of the second member 19b of the pedestal
o and two arms 32 are provided as transfer means for transferring the wafer 31 between the reaction chamber and the mounting table 30 while the wafer 31 is placed on the second member 19b of the wafer support. This arm 32 is made of heat-resistant material such as quartz, for example.
It is made of a material that is corrosion resistant. Furthermore, a wafer transfer device 33 for transferring the wafer 31 between the univaccent and the mounting table 30 (not shown) is provided near the mounting table 3o.

To explain the operation of the vapor phase growth apparatus having the above configuration using polycrystalline/recon growth as an example, first, power is supplied to the infrared lamp 17 via a power adjustment unit (not shown) to raise the wafer temperature to 600°C or higher. heating to a specified temperature. At this time, while rotating the wafer support stand 19 by the rotation means 23 via the support post 22, the gas supply port 14
By supplying a helium-based gas mixture containing a reactive gas such as monosilane at an appropriate concentration through the
This mixed gas flows toward the gas exhaust port 15, and during this time, a reactive gas is separated out from the gas phase in contact with the wafer support 19, and a polycrystalline silicon film is formed on the surface of the wafer 31. At this time, only helium is supplied as a non-reactive gas through the carrier gas supply port 25. After flowing along the transparent quartz plate 13, this gas is ejected into the reaction chamber 12 along the lower surface of the partition plate 27 in the same direction as the mixed gas.

By supplying the gas in this way, a non-reactive gas film is formed on the upper layer, preventing the mixed gas containing the reactive gas from coming into contact with the solid wall surface, and preventing reaction products from adhering to the transparent quartz parts. .

In this vapor phase growth process, if a single material such as graphite coated with SiC is used for the wafer support 19, the temperature at the center of the urchin/1 support 19 will be high, and the infrared lamps in each zone of the heating block 16 will Although the temperature distribution unevenness on the surface of the wafer support 18 could not be suppressed by adjusting the power supplied to the wafer support 18, as shown in this example, infrared light is more easily transmitted through the center of the wafer support than the peripheral area. By changing the material, uneven temperature distribution was eliminated, and variations in film thickness within the wafer were improved.

Next, the wafer transfer mechanism will be described. First, after the vapor phase growth is completed, the reaction chamber is purged with a non-reactive gas, such as helium, to completely expel the reaction gas from the reaction chamber. Next, the pressure is returned to normal and the gate pulp 28 is opened. 2
The book arm 32 is movable in the direction connecting the mounting table 3Q and the wafer support table 19 and in the vertical direction, and
opens and takes it out. Naturally, the two arms are connected to the second member 1
The interval was determined so that only 9b was transferred.

The second member 19b and Unino 31 taken out of the reaction chamber
The arm carrying the wafer moves downward on the mounting table, and the wafer 31 is placed on the arm.
Then, the wafer transfer device 33 stores the unicorn 31 in a wafer cassette (not shown). Furthermore, if vapor phase growth is to be continued, a new wafer is taken out from the wafer cassette, placed on the mounting table 30, and inserted into the reaction chamber using the arm 32.

In addition, in the above embodiment, the surface and surroundings of the second member 19b of the wafer support 19 are exposed to the reaction gas, and the temperature also becomes high, so that reaction products adhere to the second member 19b. When the second member 19b comes to the outside of the reaction chamber, that is, to the position of the mounting table, it can be replaced with another one and cleaned.

In this example, the wafer was directly taken out from the reaction chamber into the atmosphere, but a vacuum preliminary chamber was provided with a gate pulp in between, and a mounting table and an arm were installed in the vacuum preliminary chamber to expose the reaction chamber to the atmosphere. It is also possible to transfer the wafers without having to do so.

Further, in this embodiment, the vapor phase growth of polycrystalline silicon has been described, but it goes without saying that the present invention can be used for vapor phase growth of other silicon oxides, silicon nitrides, and the like.

Effects of the Invention As described above, in the present invention, the center of the wafer support is made up of a first member with a low absorption rate of infrared light, and the outer periphery is made up of a second member with a high absorption rate of infrared light. By providing a transfer means for transferring the second member on which the wafer is placed to the outside of the reaction chamber, the wafer transfer mechanism is simple, and a high-quality film can be formed with good uniformity, and the effect is outstanding. It is what it is.

[Brief explanation of drawings]

Fig. 1 is an external view of a vapor phase growth apparatus according to an embodiment of the present invention, Fig. 2 is a sectional view showing a reaction chamber of the same apparatus, and Fig. 3 is a wafer support stand used in an embodiment of the present invention. 4 is a sectional view of a reaction chamber of a conventional vapor phase growth apparatus, and FIG. 5 is a schematic perspective view showing a part of a conventional vapor phase growth apparatus equipped with a wafer conveying means. 12...Reaction chamber, 13...Transparent quartz plate, 17...Infrared lamp, 19...Wafer support stand, 23...Rotating means, 28...・・・・・・
Gate pulp, 30...Placement stand, 31...-
...Wafer, 32...Arm. Name of agent: Patent attorney Toshio Nakao 1 person! q
---Wafer sentence J to table 23- Rotation! X 28--Date l and Rude Fig. 1 30-1 size of paddy 52-m-Arm Fig. 3 Fig. 4

Claims (3)

[Claims] (1) A reaction chamber that is equipped with a gas supply port, a gas discharge port, and a gate valve for loading and unloading wafers, and a part of the wall surface is made of a material that transmits infrared light; an infrared lamp that irradiates infrared light to the reaction chamber; and an infrared lamp located inside the reaction chamber at a position where it is almost uniformly irradiated with the infrared light emitted by the infrared lamp, and whose center part has a low absorption rate of infrared light. a wafer support stand made of a first member, the part surrounding the side surface of the first member being made of a second member having a high absorption rate of infrared light; a rotating means for rotating the support table; a mounting table located outside the reaction chamber on which the wafer taken out from the gate valve and the second member are mounted; and a transfer means for transferring the second member. (2) The first member of the wafer support is made of quartz, and the second member is made of quartz.
The vapor phase growth apparatus according to claim 1, wherein the member is made of graphite. (3) The inner diameter of the second member of the wafer support stand is smaller than the diameter of the wafer to be processed, and the mounting stand installed outside the reaction chamber consists of two stages, upper and lower, with the upper part being smaller than the inner diameter of the second member of the wafer support stand. The vapor phase growth apparatus according to claim 1, wherein the vapor phase growth apparatus has a substantially cylindrical shape having a small diameter.