JPH0532902B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a vapor phase growth apparatus, and particularly to uniform heating of a wafer subjected to vapor phase growth.

(Prior Art) RF heating and radiation heating are used to heat a wafer in a conventional vapor phase growth apparatus, particularly an epitaxial vapor phase growth apparatus. For RF heating, the wafer is placed on a carbon susceptor and the susceptor is heated.
The wafer is heated from the back side by induction heating using an RF coil, while the wafer is heated from the back side by radiant heating, which is done by placing the wafer on a susceptor and heating the wafer by radiation from the front side of the wafer and susceptor using an infrared lamp or the like. Direct radiation heating from the front side and heating from the back side with a susceptor, or parallel heating that emits infrared rays as in Japanese Patent Publication No. 63-6627.
There is a method in which the wafer is placed between two heating plates and is directly heated by radiation from both the front and back sides.

(Problem to be Solved by the Invention) As is well known, the above-mentioned RF heating has the drawback that the wafer is heated from the back side, which causes a temperature difference between the front and back sides.For this reason, radiant heating is applied from the front side. It is. The above-mentioned Japanese Patent Publication No. 63-6627 can heat the front and back surfaces of a wafer more uniformly, but the flat heating plate used in this method dissipates a lot of heat at the periphery, so The temperature tends to be lower at the outer periphery than at the outer periphery. Therefore, it is necessary to make the area of the heating plate considerably larger than the wafer placement part. In particular, when wafers are placed on one heating plate in a state where they are substantially in contact with each other without leaving any space between them, the wafer is sensitive to the temperature of the heating plate, so the temperature of the wafer placement area Because of the need to make the temperature more completely uniform, it is necessary to further increase the area of the heating plate.

An object of the present invention is to provide a vapor phase growth apparatus that can achieve uniform heating of a wafer with a smaller apparatus.

[Structure of the invention]

(Means for Solving the Problems) A vapor phase growth apparatus of the present invention for achieving the above object is a cold wall type vapor growth apparatus that forcibly cools the outer wall of the reaction chamber. A flat cylindrical heating section has an opening on the gas inlet side and the other side as the exhaust side, in which the wafer is directly or indirectly placed, and a heating section outside the reaction chamber that heats the entire outer peripheral surface of this heating section. A radiation heating means is provided, and a reaction gas is caused to flow through at least the heating section.

Preferably, the heating section has a substantially flat rectangular tube shape, and radiation heating means are provided corresponding to each of the four outer peripheral surfaces of the rectangular tube shape.

Furthermore, the wafer may be placed on the inner wall of the heating section in the same way as the wafer is placed on a susceptor in a normal vapor phase growth apparatus, or the wafer may be placed on the inner wall of the heating section. A support member may be provided separately for the wafer and the wafer may be placed on the support member.Furthermore, most or all of the wafer, except for the vicinity of the outer periphery, on both the front and back sides of the wafer may be placed so as to face the two opposing inner walls of the heating section at a distance from each other. It may also be placed so that it

(Function) The wafer is placed in a flat cylindrical heating section,
The heating section receives heating by heat conduction and radiation from the inner wall of the heating section, or heating by substantially only radiation from the front and back and the surroundings. At this time, the heating section heats substantially the entire outer circumferential surface of the wafer, including not only the outer circumferential surface portions corresponding to the front and back sides of the wafer, but also the side portions, so the temperature inside the heating section is more uniform from the center to the edges. Therefore, even if the width of the internal space of the heating section, particularly in the direction perpendicular to the gas flow, is made close to the diameter of the wafer, the entire wafer can be heated uniformly with high precision.

It is preferable that the height of the internal space of the heating section is as small as possible. This increases heating efficiency and stabilizes the wafer temperature. Furthermore, since the cross-sectional area of the entire reaction chamber can be reduced, the effective use of gas and the amount used can be achieved. This will result in a reduction in

(Example) The following Figures 1 and 2 show an example of the present invention.
This will be explained with reference to the figure. Reference numeral 11 denotes a reaction vessel made of quartz glass that forms the reaction chamber 10, and its cross-sectional shape is a flat rectangular cylinder as shown in FIG. 2. In FIG. It is fixed to the device frame 13 by tightening with.

A hole 12a that substantially coincides with the inner wall of the reaction vessel 11 is formed in the clamping plate 12, and a gas supply member 14 made of stainless steel is fitted into this hole 12a. In the center of the gas supply member 14, there is a flat stepped hole 1 for supplying reaction gas and purge gas.
5 is opened, and an annular groove 16 for supplying purge gas is formed on the outer periphery of the engagement portion with the tightening plate 12.
is provided. The stepped hole 15 and the annular groove 16 are provided with channels 17 and 1 provided in the tightening plate 12.
Reactant gas or purge gas is supplied from first and second pipes 19 and 20 via pipe 8 .

A lid 21 is removably attached to the left end of the tightening plate 12 in FIG. 1, and the lid 21 seals the left end of the stepped hole 15. A rectifying plate 23 is attached to the lid 21 via a plurality of rods 22 so as to correspond to the stepped portion of the stepped hole 15. This rectifying plate 23 is a punched metal type having a large number of small holes.

A flat gas introduction pipe 24 made of quartz glass is connected to the right end of the stepped hole 15 in FIG. Further, the gas supply member 14 is provided with a large number of gas introduction ports 25 that connect the annular groove 16 to the space between the inner wall of the reaction chamber 10 and the outer periphery of the gas introduction pipe 24 .

Inside the reaction chamber 10, a heating section 26 made of carbon and coated with SiC on the surface is installed via a tray 27 made of quartz glass. This heating section 26
consists of a lower heating element 26a with a cross-sectional shape extending in the left-right direction in FIG. The wafer W is placed on the wafer W. Note that this heating section 26 may be formed in any suitable manner, such as being integrally formed or divided into four parts vertically, horizontally, and horizontally. This heating section 26
In FIG. 1, when the upper heating element 26b is horizontal, the bottom wall of the lower heating element 26a is sloped so that the right side is about 2 degrees higher than the left side in FIG. Heating section 2
6, the opening on the left side is connected to the gas introduction pipe 24 with a slight gap, and the opening on the right side is open toward the exhaust port 28 at the right end of the reaction vessel 11. Here, the stepped hole 1
5. The internal cross-sectional shapes of the gas introduction pipe 24 and the heating section 26 are formed to substantially match each other.

The periphery of the reaction vessel 11 is covered with a cover 29, and radiation heating means 30, 31, 32, 33 (see FIG. 2) are provided inside the cover 29 at a portion facing the heating section 26. In FIGS. 1 and 2, the radiant heating means 30 and 31 located above and below face the upper and lower outer peripheral surfaces of the heating section 26, and a rod-shaped infrared lamp 34 is connected to the second
A plurality of them are arranged at intervals in the left-right direction in the figure, and in the left-right direction in FIG. In FIG. 1, these plurality of infrared lamps 34 are divided into three sections, two each on the left, center, and right, so that their output can be adjusted. Also, in Figure 2,
Radiation heating means 32 and 33 facing the left and right outer peripheral surfaces of the heating section 26 have rod-shaped infrared lamps 34 attached along the longitudinal direction of the left and right outer peripheral surfaces.

Each infrared lamp 34 is attached to a lamp housing 35 having a reflection and cooling function, and is supplied with cooling air from each supply port 36.
4 and reaction vessel 11. Further, a supply port 37 is provided near the right end of the cover 29 in FIG. 1 to supply cooling air into the cover 29, that is, around the reaction vessel 11. Note that in FIG. 1, an exhaust port 38 is provided near the left end of the cover 29.

Next, the operation of this device will be explained. The wafer W is carried in and out by removing the lid 21. Lid 2
1, the rectifying plate 23 located at the step of the stepped hole 15 is removed, and the internal space of the heating section 26 is opened to the left end side in FIG. 1 through the stepped hole 15 and the gas introduction pipe 24. Ru. Therefore, stepped hole 15
The wafer W is loaded and unloaded from the side by a transport device (not shown).

After loading the wafer W, the first and second pipes 1
Purge gas such as N ₂ gas and H ₂ gas is supplied from 9 and 20, and temperature rise is started by the radiant heating means 30 to 33. In this heating, the temperature distribution in the left and right (longitudinal) direction in FIG. 1 of the heating section 26 is as follows:
The output of each infrared lamp 34 of the radiant heating means 30, 31 is adjusted for each section on the left, center, and right to make it uniform, and on the other hand, the temperature of the heating section 26 in the left and right (width) direction in FIG. The distribution is made uniform by adjusting the output of the radiant heating means 32, 33. In addition, as shown in FIGS. 1 and 2, when the wafer W is placed directly on the bottom wall of the heating section 26, the back surface of the wafer W is substantially heated by thermal conduction, and the front surface is heated. Since it is heated by radiation from the upper inner wall of the section 26, the upper and lower radiation heating means 3
It is preferable to adjust the outputs of 0 and 31 independently to suppress the temperature difference between the front and back sides of the wafer W.
Note that it is preferable that the outputs of the left and right radiant heating means 32 and 33 can also be adjusted separately.

Once the heating section 26 reaches the vapor phase growth temperature,
Reactant gas is supplied from the first pipe 19 instead of H ₂ gas, and the stepped hole 15, the rectifier plate 26, and the gas introduction pipe 2
A reactant gas is caused to flow in a laminar flow into the heating section 26 through the wafer W to perform vapor phase growth on the surface of the wafer W. On the other hand,
H ₂ gas as a purge gas is continuously supplied from the second pipe 18 to prevent the reaction gas from directly contacting the inner wall of the reaction vessel 11 as much as possible. Note that the connections between the gas supply member 14 and the heating section 26 and the gas introduction pipe 24 are formed with a slight gap due to thermal expansion, so the reaction gas leaks from these connections, but the amount is limited. is small,
Since the purge gas flows along the inner wall of the reaction vessel 11, wall deposits are hardly generated on the inner wall of the reaction vessel 11.

In the vapor phase growth using the reaction gas flowing inside the heating section 26, the interior space of the heating section 26 is surrounded by a relatively narrow space and has a uniform temperature distribution, so that the entire wafer W is heated more uniformly and slips. In addition, the film thickness distribution becomes uniform, and efficient vapor phase growth is performed using less reaction gas. Further, by making the cross-sectional shape of the heating section 26 smaller, the cross-sectional shape of the reaction vessel 11 is also made smaller, and therefore, the flow rate of the purge gas supplied from the second pipe 20 can also be reduced.

FIG. 3 shows the main part of another embodiment of the present invention, in which the height of the internal space of the heating section 26 is reduced, and a shallow stepped portion 40 on the bottom surface supports only the vicinity of the outer periphery of the wafer W. A deep counterbore 41 is provided so that substantially the entire front and back surfaces of the wafer W are heated by radiation. Also, in this example,
The gas introduction pipe 24 is engaged with the outer periphery of the left end of the heating section 26 with a slight gap. According to this embodiment, since both surfaces of the wafer W are heated by radiation, the wafer W can be easily heated uniformly.

FIG. 4 shows a main part of still another embodiment of the present invention, in which a support member 42 made of SiC-coated carbon or quartz glass is provided in the heating section 26, and a wafer W is placed on this support member 42. With this method, the same vapor phase growth as in the embodiment shown in FIGS. 1 and 2 can be performed.

In the above embodiment, the gas introduction tube 24 is made of quartz glass, but it may be made of carbon coated with SiC. Note that this gas introduction pipe 2
4 may be omitted as shown in FIG. In this case, the wall deposit can be suppressed by cooling the reaction vessel 11 more strongly. Further, in this embodiment, the supporting member 42 or the heating section 26
The wafer W can be carried in and out by carrying it out of the reaction vessel 11.

Furthermore, a gas outlet pipe (not shown) may be placed between the heating section 26 and the exhaust port 28 to more reliably suppress gas turbulence. Furthermore, the heating section 26 does not necessarily have to be horizontal, and may be erected with its longitudinal direction or width direction up and down, and the wafer W
In addition to the above embodiment, the wafer W can be placed on the heating section 26 by placing a ring made of quartz glass or SiC coated carbon on the bottom surface of the heating section 26, so that most or the entire wafer W is placed on the heating section 26, except for the vicinity of the outer periphery of both the front and back surfaces of the wafer W. They may be arranged to face the inner walls of the two opposing sides at a distance from each other, and both the front and back surfaces may be heated by radiation instead of by conduction, as in the embodiment shown in FIG.

Next, experimental results using the apparatus shown in FIGS. 1 and 2 above will be shown. The external dimensions of the gas introduction side of the heating section 26 were 212 mm in width, 30 mm in height, and 230 mm in length, with each wall having a thickness of 6 mm, and the bottom surface was raised by 2° toward the gas exhaust side. One counterbore for placing a wafer W was provided on the bottom surface, and one 6-inch Si wafer W was placed in this counterbore. The infrared lamps 34 have six infrared lamps each on the top and bottom and one each on the left and right in FIG. heated to. As a result, a uniform temperature distribution was obtained over almost the entire heating section 26 in both the longitudinal direction and the width direction.

In addition, in the above heating state, a reaction gas containing SiH ₂ Cl ₂ B:H ₂ of 0.5:100 is supplied from the first pipe 19 at a ratio of 20/20.
As a result, the _film growth rate was approximately 1 μ/min, and the film thickness distribution error was approximately 2%. , the slip was not seen by macroscopic or microscopic examination.

Furthermore, no wall deposits were formed in the reaction vessel 11, and only some wall deposits were formed near the heating section 26 of the gas introduction pipe 24.

〔Effect of the invention〕

As described above, according to the present invention, high-quality vapor phase growth can be performed on relatively large diameter wafers such as 6-inch wafers using a small device, and the miniaturization of the device requires less heating energy and gas. It is possible to keep the amount used low and reduce running costs. Note that if the heating section is formed into a substantially flat rectangular tube shape, the heating efficiency can be increased by making the heating section thinner without impairing the uniformity of the gas flow rate in the width direction. Further, in the case of a substantially rectangular cylindrical shape, the temperature distribution in the width direction of the heating section can be made uniform by providing radiation heating means corresponding to each of the four outer peripheral surfaces.
Furthermore, the wafer may be placed on the heating section either directly or indirectly, but most or all of the wafer, except for the vicinity of the outer periphery on both the front and back surfaces, should be placed at a distance from the inner wall of the heating section. For example, the temperature difference between the front and back sides can be made smaller.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing one embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line - in FIG. 1, and FIGS. 3 to 5 show other different embodiments of the present invention. It is a longitudinal cross-sectional view of the main part. 10...Reaction chamber, 11...Reaction container, 14...
Gas supply member, 23... Current plate, 24... Gas introduction pipe, 25... Gas inlet, 26... Heating section, 2
8... Exhaust port, 30, 31, 32, 33... Radiation heating means, 34... Infrared lamp, 42... Support member, W... Wafer.

Claims (1)

[Scope of Claims] 1. A cold wall type vapor phase growth apparatus that forcibly cools the outer wall of a reaction chamber, which is disposed inside the reaction chamber and has an opening with one side as a gas inlet side and the other side as an exhaust side, and a wafer inside. It is equipped with a flat cylindrical heating section placed directly or indirectly, and a radiation heating means provided outside the reaction chamber so as to heat the entire outer peripheral surface of the heating section, and at least a reaction gas is provided inside the heating section. A vapor phase growth apparatus characterized by being configured to flow. 2. The vapor phase growth apparatus according to claim 1, wherein the heating section has a flat rectangular tube shape, and radiation heating means are provided corresponding to four outer circumferential surfaces of the rectangular tube section. 3. The vapor phase growth apparatus according to claim 1 or 2, wherein the wafer is placed directly on the inner wall of the heating section. 4. The vapor phase growth apparatus according to claim 1 or 2, further comprising a wafer support member provided within the heating section. 5. The wafer is placed in the heating section so that most or all of the wafer, excluding the vicinity of the outer periphery, on both the front and back sides of the wafer faces the two opposing inner walls of the heating section with a distance between them. The vapor phase growth apparatus according to claim 1, 2, 3, or 4, characterized in that: