JPH02279588A - Vapor growth device - Google Patents

Abstract

PURPOSE:To improve the uniformity of the distributions of the film thickness and specific resistance of the film formed on a wafer mounted on a susceptor by providing a temp. measuring plate having the same shape as the shape of the susceptor in proximity to the susceptor and controlling the temp. of the susceptor in accordance with the measured value thereof. CONSTITUTION:Gaseous raw materials are caused to flow horizontally with the susceptor 5 disposed in a device body 2. The gaseous raw materials are thermally cracked on the abovementioned susceptor 5 and the epitaxial film is formed on the surface of the wafer 3 mounted thereon. The temp. measuring plate 9 having the same shape as the shape of the susceptor 5 is disposed in proximity to the susceptor 5 of the abovementioned vapor growth device. Since plural pieces of temp.-measuring elements (thermocouple) 20 are built in this temp.-measuring plate 9, the temps. in the respective parts of the susceptor 5 are exactly measured. The temp. of the susceptor 5 is controlled in accordance therewith, by which the temp. distribution is made uniform. the distributions of the film thickness and specific resistance of the film formed on the wafer 3 are thus made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vapor phase growth apparatus for forming an epitaxial film on a wafer surface, particularly a so-called horizontal vapor phase growth apparatus, and a method of using the apparatus.

The blue five-string lid epitaxial film is a thin film formed by using a single crystal such as silicon as a substrate (wafer) and growing a single crystal in a vapor phase on top of it. This is one of the important steps in the manufacturing process of IC devices such as Bi-CMO5.

Conventionally, a type of vapor phase growth apparatus called a horizontal vapor phase growth apparatus has been widely used for forming this type of epitaxial film.

In the horizontal vapor phase growth apparatus, raw material gas is flowed from a substantially horizontal direction to a susceptor disposed within the apparatus main body, and the raw material gas is thermally decomposed on the susceptor and attached to the susceptor. An epitaxial film is formed on the surface of a wafer.

This epitaxial film is required to have a uniform film thickness distribution so as to prevent variations in performance between products.

Furthermore, in order to obtain a product with the desired high quality in this epitaxial film, uniformity and goodness of resistivity distribution are required.

Therefore, in order to obtain a wafer with a uniform film thickness distribution and a uniform resistivity distribution, the conditions for formation of pus must be uniform, and for this purpose, the velocity distribution of the source gas on the susceptor must be uniform. In addition to this, it is also necessary that the temperature distribution in the susceptor be uniform.

Therefore, in this type of vapor phase growth apparatus, attempts have been made to control the temperature distribution on the susceptor using various measures.

FIG. 7 is a cross-sectional view (first conventional example) schematically showing the main parts of a currently commercially available horizontal vapor phase growth apparatus equipped with such a concentration distribution control mechanism. In the vapor phase growth apparatus, a susceptor 52 that is rotationally driven in the direction of arrow X is disposed within the apparatus main body 51, and a ring member 53 made of carbon coated with silicon carbide is provided around the susceptor 52. Thermocouples 54a are embedded in an appropriate number of locations in the ring member 53, and thermocouples 54b are also introduced into the rotating shaft 55 of the susceptor 52, making it possible to measure the temperature of the periphery and center of the susceptor 52. has been done. That is, in this vapor phase growth apparatus, film formation is performed while rotating the susceptor 52 in the direction of the arrow X so that the temperature distribution in the circumferential direction is uniform.
An appropriate number of thermocouples 54a embedded therein and a thermocouple 54b introduced from the rotating shaft 55 detect the temperature of the susceptor 52 heated by the heat from the heater section 56, and determine the temperature. was in control.

FIG. 8 shows another conventional example (second conventional example) of a horizontal vapor phase growth apparatus, in which a susceptor 62 formed in a rectangular shape is located inside the apparatus main body 51. The susceptor 6 is fixed to the susceptor 6 in an inclined shape with a higher downstream side.
A plurality of thermocouples 54c... are embedded in 2. That is, in this vapor phase growth apparatus, the thermocouples 54c... are embedded in the susceptor 62, and the susceptor 62
By directly measuring the temperature of each part of the susceptor 62, the temperature of the susceptor 62 heated by the heat from the heater part 56 is detected and temperature control is performed.

Note that the reason why the susceptor 62 is provided in an inclined state is that by narrowing the cross-sectional area of the flow velocity on the downstream side, the flow velocity in the flow direction (indicated by arrow Y) decreases and a stagnation layer is created.
This is to prevent the thickness of the pus layer from increasing, and to prevent the growth rate of pus from decreasing in the flow direction.

In the first conventional example, even when using a large susceptor 52 on which a plurality of wafers 57 can be placed, the center 58 of the susceptor 52 and the susceptor 52 The temperature could only be measured near the peripheral edge 59 of the susceptor 52. Therefore, since the temperature at the intermediate position between the center 58 of the susceptor 52 and the peripheral edge 59 of the susceptor 52 cannot be accurately determined, it is difficult to accurately control the temperature distribution. The problem was that it could not be done.

In addition, in the second conventional example, since the thermocouples 54c are directly embedded in multiple locations of the susceptor 62, it is possible to accurately measure the temperature of each part of the susceptor 62, and the temperature can also be controlled accurately. It is possible to do so. However, although the susceptor 62 is arranged horizontally inclined to equalize the film growth rate in the flow direction, the susceptor 62 cannot be rotated, and the velocity distribution changes rapidly. In such cases, it is impossible to adapt to changes in the velocity distribution, and it is difficult to form an epitaxial film that always has a uniform thickness distribution. That is, in the second conventional example, the velocity distribution of the raw material gas in the flow direction and the width direction is often nonuniform, and even if temperature control is performed accurately, the epitaxial film has a uniform thickness distribution. There was a problem in that it was difficult to always form the wafer 57 on the wafer 57.

Furthermore, in both the first and second conventional examples, since the wafer 57 is placed on the susceptor 52, 62, the upper plate 60 of the apparatus main body 51 is
Crystal flakes attached to the wafers 57 may peel off from the upper plate 60 and fall onto the wafers 57 . Therefore, there is a problem that the crystal flakes may be mixed into the epitaxial film on the wafer 57.

The present invention has been made in view of these problems, and by making the reaction temperature distribution uniform on the wafer, the uniformity of the film thickness distribution and resistivity distribution is improved.
An object of the present invention is to provide a vapor phase growth apparatus capable of forming a high quality epitaxial film and a method for using the same.

To solve the problems r In order to achieve the above object, a vapor phase growth apparatus according to the present invention has a method in which a raw material gas is flowed from a substantially horizontal direction to a susceptor disposed in the main body of the apparatus, and further the raw material gas is is thermally decomposed on the susceptor to form an epitaxial film on the surface of a wafer mounted on the susceptor, wherein a temperature measuring plate having substantially the same shape as the susceptor is attached to a flat surface of the susceptor. are arranged opposite to and in close proximity to,
The first feature is that the temperature measuring plate includes a plurality of temperature measuring elements.

Furthermore, in the vapor phase growth apparatus according to the present invention, the wafer is mounted on the lower surface side of the susceptor with the surface facing the sea urchin facing downward.
It is a feature of

5■ According to the above configuration, the temperature measurement plate having approximately the same shape as the susceptor,
The temperature measuring plate is disposed opposite to and close to the flat surface of the susceptor, and has a plurality of temperature measuring elements built into the temperature measuring plate, so that the temperature of each part of the susceptor can be measured with high accuracy. Become.

Furthermore, by mounting the wafer on the lower surface side of the susceptor with the surface of the wafer facing downward, crystal flakes attached to the upper plate of the apparatus main body due to the diffusion of the raw material gas may peel off and fall from the upper plate. However, these crystal flakes do not mix into the epitaxial film.

Ru.

FIG. 1 is a front sectional view showing a horizontal vapor phase growth apparatus according to the present invention, which includes an apparatus body 2 made of quartz and a plurality of wafers 3... a susceptor 5 placed on the susceptor 5; a heater section 6 that heats the inside of the device main body 2;
A temperature measuring plate 9 disposed close to and opposite to the flat part 5a on the lower surface side of the susceptor 5, an injection pipe 10 for supplying raw material gas (including carrier gas) into the apparatus main body 2, and a temperature measuring plate The main part is a control section (not shown) that detects the temperature of the plate 9 and controls the output of the heater section 6 as appropriate.

The apparatus main body 2 includes a reaction tube 11 having a rectangular cross section, a side wall portion 12 to which an injection pipe IO is connected, and an exhaust portion 13 that exhausts unreacted source gas in the direction of the arrow.

The susceptor 5 is made of carbon coated with silicon carbide,
It is formed into a circular shape in plan view and is rotatable in the direction of arrow E. 14 is a bearing seal portion of the susceptor 5.

The heater section 6 includes a plurality of infrared lamps 15 arranged in a row in the width direction above and below the device main body 2, and heats the inside of the device main body 2 by reflecting the heat of these infrared lamps 15. The main part is a reflecting plate 16 that contributes to the reflection. Further, the heater part 6 is divided into a plurality of zones, and the control part appropriately controls the output of the infrared lamps 15 for each zone according to the temperature of each part of the temperature measuring plate 9. Temperature controlled.

Similarly to the susceptor 5, the temperature measuring plate 9 is made of carbon coated with silicon carbide and has the same circular shape as the susceptor 5 in plan view. It is fixed to the bottom plate 18.

Furthermore, a plurality of thermocouples 20... are embedded in the temperature measuring plate 9. That is, in this embodiment, as shown in FIG. 2, a hole is provided in the center of the temperature measuring plate 9 so that the rotating shaft 19 of the susceptor 5 can be inserted therethrough, and a hole is provided in the center of the temperature measuring plate 9 to allow the flow of the raw material gas. Twelve thermocouples 20 are embedded so that the temperature of each part in the direction (indicated by arrow F) and the direction perpendicular to the flow direction (indicated by arrow G) can be measured, and these thermocouples 20 ...is a quartz glass tube 21...
・Covered with

In the vapor phase growth apparatus configured as described above, an epitaxial film is formed on the surface of the wafer 3 in the following manner.

First, after mounting a plurality of wafers 3... on the susceptor 5, the susceptor 5 is driven to rotate in the direction of arrow E, and the power source of the heater unit 6 is turned on to turn the wafers 3...
and heat the susceptor 5 to about 1000°C. After this, silicon gas such as 5IH4, 5LHC11 and H7
, He, etc., and a carrier gas such as He is supplied into the apparatus main body 2 from the injection pipe IO.

When this raw material gas reaches above the susceptor 5,
The silicon-based gas causes a decomposition reaction due to the heat from the heater section 6, and the silicon is transferred to the wafer 3 on the susceptor 5.
・is deposited on the surface of the epitaxial film to form an epitaxial film.

Therefore, by using the vapor phase growth apparatus according to the present invention, it is possible to make the temperature distribution on the susceptor uniform, and it is possible to obtain an epitaxial film with improved uniformity in film thickness distribution and resistivity distribution. can.

That is, a plurality of thermocouples 20 embedded in the temperature measuring plate 9
. . . The approximate temperature of each part of the susceptor 5 is measured, and these temperature measurements are converted into electrical signals and sent to the control section (not shown). Furthermore, the control section controls the output of the infrared lamps 15 in each zone of the heater section 6 divided into a plurality of zones, thereby making the temperature distribution on the susceptor 5 uniform. Strictly speaking, the temperature of each part of the temperature measuring plate 9 is different from the temperature of the susceptor 5, but the temperature distribution is considered to have a high correlation with the temperature distribution on the susceptor 5. Therefore, by disposing a temperature measuring plate 9 having substantially the same shape as the susceptor 5 in the vicinity of the flat part 5a on the lower surface side of the susceptor 5, and measuring and controlling the temperature of the temperature measuring plate 9, the temperature of the susceptor 5 can be measured. Uniform temperature distribution can be achieved.

Table 1 shows the experimental results of film thickness distribution and resistivity distribution when the temperature is controlled using the vapor phase growth apparatus according to the present invention. This is shown in comparison with Figure). In this experiment, the film was formed after pre-treating the wafer 3 with hydrogen, and the raw material gas was 5iHC1i''
Hg was used.

As is clear from Table 1, by using the vapor phase growth apparatus according to the present invention, it is possible to form an epitaxial film with improved uniformity of film thickness distribution and resistivity distribution compared to the conventional example. I understand.

As described above, by using the vapor phase growth apparatus according to the present invention, the temperature distribution on the susceptor 5 is made uniform, the uniformity of the film thickness distribution is improved, and the probability of impurities being mixed into the epitaxial film is also constant. This also improves the uniformity of the resistivity distribution.

FIG. 3 is a front cross-sectional view showing a second embodiment, in which the wafer 3 is mounted on the lower surface side of a susceptor 30 with the front surface 22 of the wafer 3 facing downward. It is something that

Specifically, as shown in FIG.
3... formed thereon, and a plurality of holding plates 26 having cylindrical protrusions on the lower side, which are placed on the upper surface 25 of the susceptor body 24 above the holes 23. Become. Further, a flange portion 27 is formed in the hole 23 so that the wafer 3 can be locked therein. The surface of the wafer 3 (the surface on which the epitaxial film is formed)
With 22 facing downward, remove the flange 2 of the susceptor body 24.
7 and is also fixed to the susceptor 30 by the presser plate 26. The susceptor body 24 and the presser foot 26 are both made of carbon coated with silicon carbide.

With the wafer 3 facing downward with its surface 22,
Since the wafer 3 is mounted on the lower surface 7 side of the susceptor 30, even if crystal flakes attached to the upper plate 28 of the reaction tube 11 peel off and fall from the upper plate 28, they will not be formed on the surface 22 of the wafer 3. It is possible to prevent crystal flakes from being mixed into the epitaxial film, and a high quality epitaxial film can be formed on the surface 22 of the wafer 3.

FIG. 5 is a front sectional view showing the third embodiment, in which a temperature measuring plate 35 is disposed close to the flat portion 30a on the upper surface side of the susceptor 30. That is, the temperature measurement plate 35 is
It is fixed to the upper plate 28 of the reaction tube 11 via the support member 17b. In the second embodiment, the susceptor 30
Since it is necessary to flow raw gas between the susceptor 30 and the temperature measurement plate 9, there is a certain limit to the proximity distance between the susceptor 30 and the temperature measurement plate 9. However, in this third embodiment, the susceptor 3
The temperature measuring plate 35 is connected to the susceptor 30 within the range where it does not touch the temperature.
As a result, the temperature of the temperature measuring plate 35 and the temperature of the susceptor 30 become closer to each other, making it possible to perform highly accurate temperature control. Moreover, since the temperature measuring plate 35 is fixed to the upper plate 28 of the reaction tube 11, there is no need to provide a hole in the center of the temperature measuring plate 35, as shown in FIG. Can be measured at one point.

Furthermore, as in the second embodiment, since the wafer 3 is attached to the lower surface of the susceptor 30, it goes without saying that it is possible to prevent crystal flakes from entering the epitaxial film.

It goes without saying that the present invention is not limited to the above-mentioned embodiments, and may be modified without departing from the scope of the invention. Furthermore, temperature control can be performed by providing more measurement points depending on the size of the susceptor. Furthermore, although a thermocouple was used as the temperature measuring element in the above embodiment, other temperature measuring elements such as an optical fiber thermometer may also be used to achieve the intended purpose in the same manner as described above.

As described in detail above, in the vapor phase growth apparatus according to the present invention, a temperature measuring plate having substantially the same shape as the susceptor is disposed opposite to and close to the flat part of the susceptor, and Since a plurality of temperature measuring elements are built into the temperature measuring plate, the temperature of each part of the susceptor can be accurately measured with high precision even in a device in which the susceptor rotates.

Then, the temperature at a plurality of locations on the temperature measuring plate is measured using a plurality of 1ii
By controlling the temperature of the susceptor using the temperature of the temperature measuring plate, the temperature distribution of each part of the susceptor can be made uniform, and the temperature distribution of the epitaxial film formed on the wafer can be made uniform. The uniformity of film thickness distribution and resistivity distribution can be improved.

In addition, by mounting the wafer on the lower surface side of the susceptor with the surface of the wafer facing downward, crystal flakes attached to the upper plate of the apparatus main body due to the diffusion of the raw material gas may peel off from the upper plate and fall. However, these crystal flakes do not mix into the epitaxial film, and a high quality epitaxial film can be formed on the surface of the wafer.

And, the vapor phase growth apparatus of the present invention such as CCD and B1-CMO
By applying it to the manufacturing process of IC devices such as S,
A remarkable effect is that high-performance IC devices can be manufactured.

[Brief explanation of drawings]

FIG. 1 is a front sectional view showing one embodiment of the present invention. 2 is a view taken along arrows II-TI in FIG. 1, FIG. 3 is a front sectional view showing the second embodiment, FIG. 4 is an enlarged sectional view of the main part (part B) in FIG. 3, and FIG. 6 is a front sectional view showing the third embodiment, FIG. 6 is a view along the IV-IV arrow in FIG. 5, FIG. 7 is a front sectional view showing the first conventional example, and FIG. 8 is a front sectional view showing the second conventional example. It is a front sectional view showing a conventional example. 2... Apparatus main body, 3... Wafer, 5.30... Susceptor, 5a, 30a... Flat part, 9.35... Temperature measurement plate, 20... Thermocouple (for temperature measurement) element), 22... surface of the wafer. Patent applicant/Sumitomo Metal Industries Co., Ltd. Agent:
Patent attorney Ryuji Bennai's funeral map Figure 2 Figure 5 Figure 3 Figure 7

Claims (2)

[Claims] (1) Raw material gas is flowed from a substantially horizontal direction to a susceptor disposed within the apparatus main body, and the raw material gas is thermally decomposed on the susceptor to form an epitaxial film on the surface of the wafer mounted on the susceptor. is formed, wherein a temperature measuring plate having substantially the same shape as the susceptor is disposed opposite to and close to a flat surface of the susceptor, and a plurality of temperature measuring plates are provided on the temperature measuring plate. A vapor phase growth apparatus characterized by having a built-in temperature measuring element. (2) The vapor phase growth apparatus according to claim 1, wherein the wafer is mounted on the lower surface side of the susceptor with the surface of the wafer facing downward.