JPH06326038A - Vapor growth device - Google Patents

Abstract

PURPOSE:To provide a small-sized vapor growth device with no variability of the thickness of film deposited on the surface of wafer and among wafers, simultaneously treating a plurality of semiconductor wafers. CONSTITUTION:In a vapor growth device, in which a plurality of semiconductor wafers are treated simultaneously, a wafer susceptor 2, to which wafer pockets 3, on which a plurality of the semiconductor wafers 1 are placed horizontally, are formed at a plurality of steps, a reaction pipe 5, into which the wafer susceptor 2 is charged and in which a vapor growth reaction is conducted, a means rotating the wafer susceptor 2 in the reaction pipe 5, a gas blow-off port 7 for vapor growth formed at every step of the wafer pickets 3 and a means controlling a gas flow rate are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor phase growth apparatus used for manufacturing semiconductor wafers and the like.

[0002]

2. Description of the Related Art A film forming method (CV) utilizing a chemical vapor reaction
Compared to other film forming methods, D) is (1) that impurities can be easily added at the time of film formation, (2) that a high-purity gas can be used to form a high-quality film, and (3) that a reaction source is used. There are many advantages such as the ability to form various insulating films, semiconductor films, and metal films by selection, and (4) good step coverage. Therefore, in the LSI manufacturing process, it is currently used as a Si-based thin film forming method for forming a gate wiring material, an interlayer insulating film passivation film, and the like, and is an important process technology. In recent years, with the progress of higher precision and higher integration of LSI, it has become necessary to form a thin film having more uniform electrical characteristics and film thickness. It is required to form a thin film.

Cross-sectional views of a typical apparatus for performing this CVD are shown in FIGS. 4 and 5. 1 is a wafer, 2 is a wafer support (wafer boat in FIG. 4, susceptor in FIG. 5),
3 is a wafer pocket, 4 is a hatch, 5 is a reaction tube, 6 is a gas supplied into the reaction tube 5, and the direction of the flow is shown by an arrow. Reference numeral 7 is a gas supply port, 8 is a gas discharge port, and 9 is a heater for heating. The numbers are common to FIGS. 4 and 5.

FIG. 4 shows a diffusion furnace type CVD apparatus in which the wafer 1 is vertically laid on a wafer boat 2 and placed on the wafer boat 2, and the hatch 4 is opened and inserted into the reaction tube 5. The supply gas 6 is supplied into the reaction tube 5 through the gas supply port 7 and exhausted through the gas discharge port 8. A heater 9 for heating is arranged around the reaction tube 5 in order to make the temperature in the reaction tube 5 uniform when the supply gas 6 is supplied. This CVD apparatus is characterized by a simpler structure, better temperature uniformity, and a larger number of processed sheets per time than other apparatuses.

FIG. 5 shows a vertical (disk type) CVD apparatus,
In the above structure, the wafer 1 is placed horizontally on the susceptor 2. The loading and unloading of the wafer 1 is performed by raising and lowering the reaction tube 5. The supply gas 6 is a gas supply port 7 provided at the center of the susceptor 2.
Is supplied to the inside of the reaction tube 5 from the gas exhaust port 8. When supplying the supply gas 6, the susceptor 2 is rotated. The heating heater 9 is a high-frequency coil that conducts heat to the wafer 1 through the susceptor 2. This CVD apparatus is characterized in that the flow of the supply gas is more uniform than other apparatuses.

[0006]

However, the above-described conventional example has the following drawbacks due to the above-described configuration and operation.

In the case of the diffusion furnace type CVD apparatus shown in FIG.
Since the supply gas 6 flows as shown by the arrow, depending on the type of thin film to be formed (for example, a single crystal silicon thin film), the gas reacts further upstream in the reaction gas flow, and the reaction gas flow rate becomes substantially lower downstream. Decrease. From this, the formed film thickness becomes thinner from the upper end to the lower end within the wafer surface. Further, between the wafers processed at the same time, the formed film thickness becomes smaller as the wafer leans toward the back of the wafer boat. That is, there is a drawback that the film thickness varies between the wafer surfaces and between the wafers.

In the case of the vertical CVD apparatus shown in FIG. 5,
By utilizing the gas convection, it is possible to improve the film thickness variation within the wafer surface and between the wafers, but for this reason, the volume of the reaction tube must be large. Further, since the susceptor has a disc shape, the diameter of the susceptor has to be increased when the number of processed sheets is increased, which causes a problem that the device becomes extremely large.

[Object of the Invention] It is an object of the present invention to provide a vapor phase growth apparatus for simultaneously processing a plurality of semiconductor wafers, in which there is no variation in film thickness within a wafer surface and between wafers, and a small apparatus is provided. It is to be realized.

[0010]

SUMMARY OF THE INVENTION The present invention provides a vapor phase growth apparatus for performing vapor phase growth by inserting a wafer supporter having a plurality of wafer pockets for horizontally mounting a plurality of wafers horizontally into a reaction tube. By providing a means for rotating the wafer support in the reaction tube, and a means for providing a gas outlet for each stage of the wafer pocket and controlling the gas flow rate thereof,
(EN) A vapor phase growth apparatus capable of forming a uniform thin film in a plane of a wafer without variation between wafers, excellent in mass productivity, small in size, and consuming less gas.

[0011]

According to the present invention, by supplying the supply gas from the gas supply port arranged in each stage of the wafer pocket in the reaction tube, it is possible to compensate for the decrease in the flow direction of the supply gas, and to process at the same time. It is possible to suppress variations in the formed film thickness between the wafers.

By rotating the wafer support, the heat distribution and the gas flow rate on the wafer surface can be made uniform, and a uniform thin film can be formed.

Further, the apparatus can be made smaller in capacity and smaller than the number of processed sheets, and the gas consumption can be reduced.

Further, by adopting the method of horizontally mounting the wafers, automation such as robot transfer is easy, and since a large number of wafers can be processed at the same time, mass productivity can be improved.

Further, by providing the conical convex surface on the surface of the wafer support table facing the wafer, the supply gas flows so as to make up for the decrease in the supply gas consumed at the outer peripheral portion of the wafer, and The uniformity of the formed film thickness in the plane is improved.

Furthermore, by providing a ring-shaped convex portion at a location corresponding to the outermost peripheral portion of the wafer having a conical convex surface, it is possible to improve the "edge sagging" in which the film thickness of the wafer becomes thin at the outermost peripheral portion of the wafer, A film having a uniform thickness can be formed on the entire surface of the wafer.

It is possible to design various shapes for such an uneven surface by analyzing the gas flow.

Further, the wafer support is made of transparent quartz, and the infrared lamp for heating and the reflecting means are provided therein, so that the number of lamps required for the wafer is smaller than that in the case where the infrared lamp is arranged around the reaction tube. It can be heated more efficiently.

Further, since both surfaces of the wafer can be heated by the infrared lamp, it is possible to prevent uneven heat applied to the wafer and warp of the wafer.

[0020]

[First Embodiment] FIG. 1 shows the first embodiment of the present invention. Here, 1 is a wafer, 2 is a susceptor for mounting a wafer (wafer support base), 3 is a wafer pocket provided on the susceptor 2, 4 is a hatch for loading and unloading the wafer,
Reference numeral 5 denotes a reaction tube, 6 denotes a gas supplied into the reaction tube 5, and the flow direction is indicated by an arrow. 7 is a gas supply port, 8 is a gas discharge port,
Reference numeral 9 is an infrared lamp for heating.

In the above structure, the hatch 4 is opened, the wafer 1 is horizontally placed on the wafer pockets 3 provided in the susceptor 2 in a plurality of stages, the hatch 4 is closed, and the susceptor 2 is attached to the reaction tube 5.
Insert inside. At the time of forming a thin film, the supply gas 6 is sent from the gas supply port 7 into the reaction tube 5 and exhausted from the gas discharge port 8. At this time, the infrared lamp 9 is turned on to heat the inside of the reaction tube and rotate the susceptor 2.

By adopting the above-mentioned configuration and operation, in the reaction tube 5, with respect to the wafers 1 arranged in each stage of the wafer pockets 3, each of the wafer pockets 3 is compensated for by the decrease in the flow direction of the supply gas 6. By supplying the supply gas 6 from the gas supply port 7 arranged in each step, it is possible to suppress the variation in the formed film thickness between the simultaneously processed wafers 1.

Further, by rotating the susceptor 2, it is possible to make the heat distribution and the gas flow rate in the wafer surface uniform, and to form a uniform thin film.

Further, the apparatus can be made smaller in capacity and smaller than the number of processed sheets, and the gas consumption can be reduced.

Further, by adopting a method of horizontally mounting the wafers, automation of robot transfer and the like is easy, and a large number of wafers can be processed at the same time, so that mass productivity can be improved.

[Second Embodiment] A second embodiment of the present invention is shown in FIG. The configuration and operation of FIG. 2 are similar to those of FIG.

In FIG. 2, the surface facing the wafer is not flat but has irregularities. Supply gas 6
Is supplied to the wafer 1 as shown by the arrow, the supply gas 6 is consumed much at the edge of the wafer 1, and the formed film thickness is thicker at the outer peripheral portion of the wafer 1 and thinner at the central portion. In order to improve this problem and form a uniform film, the flow rate of the reacting gas 6 is made different in the wafer plane so that the wafer 1 of the susceptor 2 can be made different.
Roughness was provided on the surface opposite to.

In FIG. 2, by providing a conical convex surface on the surface of the susceptor 2 facing the wafer 1, the supply gas flows so as to compensate for the decrease in the supply gas consumed on the outer peripheral portion of the wafer 1. The uniformity of the formed film thickness within the surface of the wafer 1 is improved. Furthermore, in order to improve the "edge sagging" in which the film thickness of the wafer 1 becomes thin at the outermost peripheral portion of the wafer 1,
A ring-shaped convex portion was provided at a location corresponding to the outermost peripheral portion of the conical convex surface of the wafer. From the above, a film having a uniform thickness can be formed over the entire surface of the wafer.

The uneven surface shown in FIG. 2 is an example, and various shapes may be designed by analyzing the gas flow, and the shape is not limited to that shown in FIG.

According to this embodiment, Si is formed on a 5-inch wafer.
When a 2.6 μm silicon single crystal film is formed using H ₂ Cl ₂ , the film thickness distribution and the specific resistance distribution are ± 3% or less within the wafer surface and ± within a batch (between simultaneously processed wafers).
3% or less, and for example, in the conventional example shown in FIG.
% And 7% and within the batch 5% and 8%, showing superiority.

[Third Embodiment] FIG. 3 shows a third embodiment of the present invention. Here, 1 to 9 are the same as those in FIGS. 1 and 2, 10 is a reflecting mirror, and 11 is a reflecting film. The operation in the above configuration is the same as in the case of FIGS.

In FIG. 3, the susceptor 2 is made of transparent quartz, and a heating infrared lamp 9 and a reflecting mirror 10 are provided inside the susceptor 2. This allows the wafer 1 to be heated more efficiently than in the case where the infrared lamp 9 is arranged around the reaction tube 5. Further, the number of heating lamps 9 can be reduced as compared with the case where the heating lamps 9 are arranged around the reaction tube 5. Further, in the case of the vertical CVD apparatus shown in FIG. 5, since the conduction heating method from the back surface of the wafer is used, there is a problem that the heat applied to the wafer 1 becomes nonuniform and the wafer 1 is warped. Since the present embodiment is a double-sided heating system using the infrared lamp 9, such a problem can be solved.

The shape of the reflecting mirror 10 and the heating lamp 9
The number and the arrangement thereof may be various other than the present embodiment, and are not limited to the case shown in FIG.

[0034]

As described above, in the vapor phase growth apparatus for performing the vapor phase growth by inserting the wafer support table having a plurality of wafer pockets for horizontally mounting a plurality of wafers into the reaction tube, the wafer support table is used. By means of rotating the wafer in the reaction tube and means for controlling the gas flow rate by providing a gas outlet for each stage of the wafer pocket, thereby forming a uniform thin film within the wafer surface and between wafers. be able to.

Moreover, since the wafers are placed horizontally at the same time, automation such as robot transfer is easy, and since a large number of wafers can be processed at the same time, excellent mass productivity can be obtained.

Further, since the volume inside the reaction tube can be made smaller than the number of processed sheets, the gas consumption can be reduced, and it is also effective for downsizing the apparatus and saving space.

The vapor phase growth apparatus can be used not only in a general vapor phase growth apparatus (CVD apparatus) but also in a vapor phase epitaxial growth apparatus.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a vapor phase growth apparatus showing a first embodiment of the present invention.

FIG. 2 is a schematic sectional view of a vapor phase growth apparatus showing a second embodiment of the present invention.

FIG. 3 is a schematic sectional view of a vapor phase growth apparatus showing a third embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of a vapor phase growth apparatus showing a first conventional example.

FIG. 5 is a schematic sectional view of a vapor phase growth apparatus showing a second conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wafer 2 Wafer support (susceptor) 3 Wafer pocket 4 Hatch 5 Reaction tube 6 Supply gas 7 Gas supply port 8 Gas discharge port 9 Heating means 10 Reflector 11 Reflective film

Claims (3)

[Claims] 1. A vapor phase growth apparatus for simultaneously processing a plurality of semiconductor wafers, comprising: a wafer support base having a plurality of wafer pockets for horizontally mounting the plurality of semiconductor wafers; and inserting the wafer support base. A reaction tube for performing a vapor phase growth reaction, a means for rotating the wafer support within the reaction tube, a gas outlet for vapor phase growth provided in each stage of the wafer pocket, and controlling the gas flow rate. A vapor phase growth apparatus comprising: 2. The wafer support base is provided with an uneven surface on a surface facing the wafer.
The vapor phase growth apparatus described. 3. The vapor phase growth apparatus according to claim 1, wherein the wafer support base is made of transparent quartz, and a lamp type heating means and a reflection means are provided therein.