JPS62154618A - Vapor growth apparatus - Google Patents

Abstract

PURPOSE:To form a film having uniform thickness on a semiconductor wafer by emitting stronger light from an infrared ray lamp than a center to the periphery of a susceptor to obtain a uniform temperature distribution on a semiconductor wafer. CONSTITUTION:A semiconductor wafer 16 is placed on a susceptor 27, and an electric power is supplied through a power regulation unit to infrared ray lamps 19 to heat the wafer 16 to a predetermined temperature. At this time, mixture gas of helium base is supplied through a gas supply port 14, a reaction chamber 9 is evacuated from a gas outlet 15 by a rotary pump to hold a reduced pressure state, and reaction gas is decomposed and precipitated from gas phase contacted with the wafer 16 to form a polycrystalline silicon film on the wafer 16. The quantity of heat radiated perpendicularly with respect to the lamps 19 is controlled by an electric power supplied to respective zones in the process of the vapor-phase growth, and the light emitted from the lamps 19 can be collected to the periphery of the susceptor 17 by bent projection 20a of a reflecting plate 20 with respect to the longitudinal direction of the lamps 19.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a vapor phase growth apparatus used in a semiconductor manufacturing process, particularly a vapor phase growth apparatus using an infrared lamp as a heating source. The vapor phase growth apparatus used in this technology separates reactive gas molecules such as monosilane on the surface of a semiconductor wafer to form a thin film of polycrystalline silicon or the like.
The thickness and uniformity of resistivity of the thin film thus formed vary greatly depending on the surface temperature of the semiconductor wafer. Therefore, in order to produce a high-quality vapor-deposited film, it is necessary to
It is necessary to maintain a uniform temperature distribution over the entire surface of the wafer.

A conventional vapor phase growth apparatus using 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 supply port 3 for discharging the reaction gas. A discharge port 4 is attached. Furthermore, a susceptor 6 on which a semiconductor wafer 6 is placed is installed on the base plate 2 . Furthermore, a semiconductor wafer 5 is placed on the outside of the quartz belljar 1.
An infrared lamp 7 for heating the semiconductor substrate 6 and an opposite plate 8 are attached so that the reflected light from the infrared lamp efficiently irradiates the semiconductor substrate 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 semiconductor wafer 5 is determined by the thermal energy supplied from the infrared lamp 7 and from the semiconductor wafer 5 and the susceptor 6. The upper surface of the susceptor 6 receives a certain amount of radiant heat from the infrared lamp 7, while the outer peripheral surface releases a large amount of heat corresponding to its surface temperature. . Therefore, the temperature distribution on the surface of the susceptor 6 is high at the center and low at the outer periphery. Also, in the case of infrared lamps themselves, the temperature of the heating element tends to be higher at the center than at the ends.

As a result, the thin film grown in vapor phase on the semiconductor Ueno\5 had the drawback that it was thinner at the edges than at the center. As a countermeasure against this, a method has been taken to control the power applied to each infrared lamp, but the susceptor 6
The temperature distribution unevenness in the longitudinal direction of each of the above infrared lamps cannot be eliminated. Furthermore, a method of rotating the susceptor has been considered, but the mechanism would be complicated, which could cause dust generation, and the unevenness of temperature distribution would not be sufficiently eliminated.

SUMMARY OF THE INVENTION Therefore, the present invention provides a vapor phase growth apparatus that eliminates the uneven temperature distribution on the surface of a susceptor, that is, a semiconductor wafer, and forms a high quality vapor phase growth film with excellent uniformity.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a reaction chamber that can be kept airtight, a part of which is made of a member that transmits infrared light, and a semiconductor inside the reaction chamber. a susceptor that holds the wafer;
a gas supply means for supplying a reaction gas to the reaction chamber; a vacuum evacuation means connected to the reaction chamber and evacuating the inside thereof; and a susceptor that is located outside the reaction chamber and is transparent to the infrared light. an infrared lamp that heats a semiconductor wafer held in the susceptor, and a reflector located at the back of the infrared lamp that reflects the irradiated light from the infrared lamp toward the susceptor, and the reflector that directs the irradiated light from the infrared lamp and the reflector. The susceptor is characterized by being provided with an irradiation control means that makes the susceptor irradiated with light reflected from the susceptor stronger at the periphery of the susceptor than at the center of the susceptor.

Function The present invention has the above-described configuration, in which the irradiation light from the infrared lamp directed onto the susceptor and the reflected light from the reflection plate are strongly applied to the central part and the peripheral part of the susceptor by the irradiation control means, Since the periphery of the semiconductor wafer or susceptor, which tends to drop in temperature due to heat radiation, is heated more strongly than the center, the temperature of the semiconductor wafer surface can be made uniform.

Embodiment An embodiment of the present invention shown in FIGS. 1 and 2 will be described.

FIG. 2 is a sectional view of the entire device. In the figure, a reaction chamber 9 is composed of a wall member 11 made of stainless steel and having a water cooling passage 10 therein, and a transparent quartz plate 12 provided above as a member that transmits infrared light. This transparent quartz plate 12 is sealed via a known gas sealing means such as an O-ring.

It is fixed to the wall member 11. One end of the side wall of the reaction chamber 9 has a gas supply port 14 connected to a gas supply pipe 13 extending from a gas supply device (not shown), and the other end has an exhaust port connected to a vacuum evacuation device such as a rotary pump (not shown). 15 are provided. Furthermore, a susceptor 17 made of graphite coated with SiC is installed inside the reaction chamber 9 on which a semiconductor wafer 16 is placed, and a transparent quartz plate +/-1- 1
A heating block 18 is attached at a position facing the susceptor 17 across the susceptor 2. This heating block 18 is
Six horizontal rod-shaped infrared lamps 19 are 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, and a reflecting plate 2o is installed behind the lamps.

These infrared lamps 19 are located on the gas supply side, in the center.

The gas discharge side is divided into three zones, each with two lamps, each electrically connected to a power adjustment unit via a socket (not shown), which controls the temperature in the direction perpendicular to each infrared lamp (gas flow direction). is possible. Reflector plates 2o provided above these infrared lamps 19
As a result, the radiant light from the infrared lamp 19 is effectively transmitted through the transparent quartz plate 12 to the susceptor 17 in the reaction chamber 9.
It is made up of 114 fl, so as to irradiate it.

In this investigation, in order to prevent the temperature from decreasing around the susceptor, a curved convex portion 20 is provided in the center of the reflector 2Q to direct the irradiated light from the infrared lamp 19 toward the susceptor's periphery.
A is curved in the longitudinal direction of the infrared lamp 19, as shown in FIGS. 1 and 2. This allows the irradiation light from each infrared lamp 19 to radiate in the direction of both ends of the lamp 19. .

The operation of the vapor phase growth apparatus with the above configuration will be explained using the growth of polycrystalline silicon as an example. First, the semiconductor wafer 16 is placed on the upper surface of the susceptor 17, and each infrared lamp 19 is connected to the infrared lamp 19 via a power adjustment unit (not shown). The semiconductor wafer 16 is heated to a predetermined temperature of 600'C or higher. At this time, a helium-based mixed gas containing a reaction gas such as monosilane at an appropriate concentration is supplied through the entire gas supply port 14, and the gas in the reaction chamber 9 is discharged from the gas discharge port 16 using a rotary pump (not shown) or the like. When it is sucked and maintained at a reduced pressure of 10 Torr or less, a reaction gas is separated out from the gas phase in contact with the semiconductor sea urchin 16, and a polycrystalline silicon film is formed on the surface of the semiconductor sea urchin 16. In this vapor phase growth process, the amount of heat radiated in the direction perpendicular to each infrared lamp 16 (gas flow direction) is controlled by the electric power supplied to each zone.
Regarding the longitudinal direction of 9, the curved protrusion 2 of the above-mentioned reflector 2o
Oa allows the irradiation light of the infrared lamp 19 to be focused around the susceptor 17, suppressing uneven temperature distribution on the surface of the semiconductor wafer 16, and improving film thickness variations within the semiconductor wafer.

FIG. 3 shows a heating block according to another embodiment of the invention.13 In this embodiment, the back of each infrared lamp 19 is made of aluminum having a parabolic cross section around the axis of each infrared lamp 19. A reflective plate 21 made of material is provided,
This allows the irradiation light from the infrared lamp to efficiently irradiate the susceptor as parallel light beams. Furthermore, each of the reflectors 21 on the backs of the four infrared lamps located at the center has both ends coated with gold, which has a high reflectance of infrared rays, and reflects the backs of the two infrared lamps placed at the ends. Board 21
The entire surface of the heating block is coated with gold to form a frame-shaped high reflection part 22 around the group of reflection plates 21, so that the peripheral part of the heating block efficiently reflects reflected light from the frame-shaped high reflection part 22. It is Nishi 2. This makes it possible to increase the irradiation rate to the periphery of the susceptor compared to the center, increase the heating l, and reduce unevenness in temperature distribution between the susceptor periphery and the center.

In the second embodiment, the reflection plate 21 has a parabolic cross-sectional shape, but it may have another shape, for example, an arc shape.

It may be flat.

In the above example, the periphery of the reflector was coated with a material with high reflection efficiency, but conversely, a material with low reflection efficiency could be coated in the center, or a material such as a transparent quartz plate could be used to transmit the irradiated light. A difference in transmittance between the peripheral portion and the central portion may be created by applying a paint that restricts the transmission of irradiated light to the central portion of the portion.

Furthermore, although this embodiment has been explained by taking the vapor phase growth of polycrystalline silicon as an example, it can be applied to other vapor phase growth, annealing equipment, etc.

Effects of the Invention According to the present invention, since the irradiation light of the infrared lamp is made to irradiate the periphery of the susceptor more strongly than the central part, it is possible to obtain a uniform temperature distribution on the surface of the semiconductor sea urchin. A uniform film can be grown on the wafer.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a heating block of a vapor phase growth apparatus used in an embodiment of the present invention, FIG. 2 is a sectional view of a vapor phase growth apparatus of an embodiment of the present invention, and FIG. FIG. 4 is a schematic diagram of a heating block of a vapor phase growth apparatus used in the embodiment, and FIG. 4 is a sectional view of a conventional vapor phase growth apparatus. 16... Semiconductor wafer, 17... Susceptor, 18... Heating block, 19...
・Infrared lamp, 20゜21・・・Reflector, 20
a... Curved convex portion, 22... Highly reflective portion. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 19-, V! ! Higashi Shiushi Lumph 0--4 deep rocb

Claims (4)

[Claims] (1) A reaction chamber that is partially made of a material that transmits infrared light and can be kept airtight, a susceptor that is located inside the reaction chamber and holds a semiconductor wafer, and a gas that supplies a reaction gas to the reaction chamber. a supply means, a vacuum evacuation means connected to the reaction chamber and evacuating the inside thereof, and an infrared ray that heats a semiconductor wafer held in a susceptor that is passed through a member that is outside the reaction chamber and that transmits the infrared light. The susceptor is provided with a lamp and a reflector located at the back of the infrared lamp to reflect the irradiated light from the infrared lamp toward the susceptor, the susceptor being irradiated with the susceptor by the direct irradiated light from the infrared lamp and the reflected light from the reflector. 1. A vapor phase growth apparatus comprising: a means for controlling irradiation to make the irradiation stronger at the periphery of the susceptor than at the center of the susceptor. (2) The vapor phase growth according to claim 1, wherein the irradiation control means is a convex portion formed in the center of the reflective surface of the reflector so as to direct the irradiated light from the infrared lamp toward the peripheral portion of the susceptor. Device. (3) The irradiation control means is for making the reflectance different between the central part and the peripheral part of the reflecting surface of the reflecting plate.
Vapor phase growth apparatus described in Section 1. (4) The vapor phase growth apparatus according to claim 3, wherein the material that makes the reflectance different is a coating material.