JPH06224133A - Chemical vapor growth device - Google Patents

Abstract

PURPOSE:To obtain a chemical vapor growth device wherein reactive gas A introduced into a gas head is prevented from being re-liquidized not to remain in the gas head, and a reaction product film can be prevented from deteriorating in deposition rate. CONSTITUTION:Inert gas B introduced into an inert gas sections 4B of a gas head 4 is heated to 60 deg.C by a ribbon heater 12 wound on an inner gas inlet pipe 10. The temperature of inert gas B is controlled white it is monitored by a thermocouple 8 provided on a partitioning plate 6. By this setup, the heat of reactive gas A is prevented from being absorbed by inert gas B through the intermediary of the partitioning plate 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is particularly applicable to room temperature (20 ° C-
The present invention relates to a chemical vapor deposition apparatus for forming a film on a semiconductor wafer using a reaction gas obtained by vaporizing a liquid reaction material that is a liquid at 25 ° C.).

[0002]

2. Description of the Related Art FIG. 4 is a cross-sectional view of an essential part showing an example of a conventional chemical vapor deposition apparatus. In the figure, 1 is a semiconductor wafer on which a reaction product film is formed, 2 is a wafer stage for holding and heating the semiconductor wafer 1, 3 is a reaction chamber accommodating the wafer stage 2, and 4 is a gas facing the wafer stage 2. This gas head 4 has a bottomed cylindrical head body 41, and a lid 42 that covers the opening of the head body 41. Further, an O-ring 43 is interposed at the joint between the head body 41 and the lid 42. Further, in the side wall portion of the head main body 41, a cooling water flow passage 41a for preventing deterioration due to heating of the O-ring 43 is provided.

The reference numeral 5A designates a reaction gas outlet for supplying the reaction gas A to the semiconductor wafer 1, which is disposed in the central portion of the lid 42.
B is an inert gas outlet arranged on the outer peripheral portion of the lid 42 for supplying an inert gas B such as N ₂ gas to the outer peripheral portion of the semiconductor wafer 1. These gas outlets 5A and 5B are
Many of them are about 5 mm in diameter,
For simplicity, the figures show only one at a time. Reference numeral 6 is a cylindrical partition plate for forming a double structure inside the gas head 4, that is, for separating the reaction gas portion 4A and the inert gas portion 4B.

Reference numeral 7 is a band heater wound around the outer periphery of the head body 41 to heat the head body 41, 8 is a thermocouple provided in the wall of the head body 41 to detect the temperature of the head body 41, and 9 is a gas head 4 10 is a reaction gas introducing pipe for introducing the reaction gas A into the reaction gas portion 4A inside, and 10 is an inert gas introducing pipe for introducing the inert gas B into the inert gas portion 4B inside the gas head 4. The ribbon heater is a ribbon heater wound around the outer peripheral portion of the reaction gas introduction pipe 9 in order to prevent reliquefaction of the reaction gas A that is gasified and introduced into the gas head 4. The ribbon heater 11 is a tape-shaped glass fiber that is electrically charged. It is provided with a heating wire. Also, the wafer stage 1
An exhaust path (not shown) for the reaction gas A and the inert gas B is provided in the outer peripheral portion surrounding the.

In the conventional chemical vapor deposition apparatus constructed as described above, the reaction gas A is supplied from the reaction gas outlet 5A to the semiconductor wafer 1 which has been heated (eg, 400 ° C.) on the wafer stage 2 in advance. Is supplied, a reaction product film is formed on the semiconductor wafer 1. At this time, if only the reaction gas A is supplied, the reaction gas A is strongly influenced by the force of being sucked into the exhaust path, particularly in the peripheral portion of the semiconductor wafer 1, so that the film thickness tends to be thinner than in the central portion. Therefore, simultaneously with the supply of the reaction gas A, the inert gas B is supplied to the peripheral portion of the semiconductor wafer 1. Then, the reaction gas A is pressed against the semiconductor wafer 1 by the pressing effect of the gas pressure of the inert gas B, and the deposition of the reaction product film is promoted. Therefore, this inert gas B
By adjusting the flow rate of the valve with a valve (not shown),
The film thickness at the peripheral portion of the semiconductor wafer 1 is controlled, and a uniform film thickness is obtained on the entire surface of the semiconductor wafer 1. Further, after the film formation, only the inert gas B is supplied to the reaction chamber 3 to replace the reaction gas A in the reaction chamber 3 with the inert gas B.

Further, by blowing out the inert gas B from the inert gas blowing port 5B, the concentration of the reaction gas A exhausted from the exhaust path is thinned, and the reaction gas A comes into contact with the CVD film on the wall of the exhaust path. Formation is suppressed. As a result, the CVD film is prevented from peeling off from the wall portion of the exhaust path and rising, and the broken pieces of the CVD film are prevented from adhering to the semiconductor wafer 1 as foreign matter, and the CVD on the wall portion of the exhaust path is prevented. The labor of removing the film is reduced.

[0007]

In the conventional chemical vapor deposition apparatus configured as described above, the temperature of the ribbon heater 11 is set to, for example, 60 ° C. to heat the introduced reaction gas A. On the other hand, the temperature of the inert gas B introduced into the peripheral portion is room temperature, that is, about 20 ° C. In addition, the band heater 7 prevents the head body 4 from removing heat of the reaction gas A.
Although heated to about 0 ° C., the inert gas B supplied into the inert gas portion 4B is hardly heated by the head body 4 because the residence time in the inert gas portion 4B is short. At room temperature, it is difficult to raise the set temperature of the band heater 7 to such an extent that the inert gas B is sufficiently heated via the head body 4 because the O-ring 43 is deteriorated. is there. Therefore, the temperature of the inert gas B in the inert gas portion 4B remains almost at room temperature, and thus part of the reaction gas A is deprived of heat by the room temperature inert gas B through the partition plate 6. It is liquefied and the liquid of the reaction gas A remains in the gas head 4, or the supply amount of the reaction gas A to the semiconductor wafer 1 is reduced and the deposition rate of the reaction product film becomes slower. There was a point.

The present invention has been made to solve the above-mentioned problems, and it is possible to prevent the reaction gas from liquefying in the gas head. An object of the present invention is to provide a chemical vapor deposition apparatus capable of preventing the liquid of gas from remaining and the deposition rate of a reaction product film from decreasing.

[0009]

The chemical vapor deposition apparatus according to the present invention comprises cooling prevention means for preventing the reaction gas in the reaction gas portion from being cooled by the inert gas introduced into the inert gas portion. Be prepared.

[0010]

In the present invention, the cooling of the reaction gas by the inert gas is prevented by the cooling prevention means, and the liquefaction of the reaction gas in the reaction gas portion is prevented.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. Example 1. FIG. 1 is a cross-sectional view of a main part of a chemical vapor deposition apparatus according to an embodiment of the present invention. The same or corresponding parts as in FIG. In the figure,
Reference numeral 12 denotes a ribbon heater as a cooling preventing means which is wound around the outer peripheral portion of the inert gas introducing pipe 10. The ribbon heater 12 serves to prevent the inert gas B introduced into the gas head 4 from flowing through the inert gas introducing pipe 10. Heating through. Further, the partition plate 6 is provided with a thermocouple 14.

In the chemical vapor deposition apparatus constructed as described above, a film is formed by a method similar to the conventional method, but when the temperature of the inert gas B in the inert gas portion 4B is low, it is vaporized. The introduced reaction gas A is reliquefied. Therefore,
A ribbon heater 12 is provided in the inert gas introduction pipe 10, and the inert gas B is heated to, for example, 60 ° C., that is, the same as the reaction gas A and introduced into the inert gas portion 4B. As a result, the heat of the reaction gas A is not taken away by the inert gas B via the partition plate 6, and the reliquefaction of the reaction gas A is prevented. Therefore, it is possible to prevent the liquid of the reaction gas A from remaining in the gas head 4 and the deposition rate of the reaction product film from decreasing.

Here, when the ribbon heater 12 is provided in the inert gas introducing pipe 10, heating can be performed in a long section of the path of the inert gas B, and heating can be efficiently performed with a heat transfer area smaller than that of the inert gas portion 4B. Therefore, the inert gas B can be heated more reliably and uniformly.

In the first embodiment, the temperature of the ribbon heater 12 is controlled by providing the thermocouple 14 on the partition plate 6 and monitoring the temperature of the partition plate 6. As a result, the decrease in the temperature of the reaction gas A can be prevented more reliably, and the ribbon heater 12 can be used efficiently.
Further, since the temperature of the partition plate 6 can be controlled by the ribbon heater 12, the temperature of the reaction gas A can also be adjusted by the ribbon heater 12.

Example 2. Next, FIG. 2 is a cross-sectional view of essential parts of a chemical vapor deposition apparatus according to another embodiment of the present invention. In the figure, the inside of the gas head 4 is separated into a reaction gas portion 4A, a first inert gas portion 4Ba, and a second inert gas portion 4Bb by cylindrical first and second partition plates 6a and 6b. It has a triple structure. The inert gas B is introduced into the first and second inert gas parts 4Ba and 4Bb through the first and second inert gas introduction pipes 10a and 10b, respectively.

Further, the first and second inert gas parts 4B
The inert gas B introduced into a, 4Bb is the first and second
Is blown toward the semiconductor wafer 1 side from the inert gas blowing ports 5Ba and 5Bb. Further, the ribbon heater 12 for heating the inert gas B is the first inert gas introducing pipe 10
a, and the thermocouple 14 is provided on the first partition plate 6a.

In such a chemical vapor deposition apparatus, the flow rate of the inert gas B introduced into the first and second inert gas portions 4Ba and 4Bb is adjusted separately, so that the semiconductor wafer 1 can be wider. The film thickness in the peripheral part of the width is controlled,
The film thickness is more surely made uniform. Also, the reaction gas portion 4A
The inert gas B introduced into the first inert gas portion 4Ba adjacent to the above is heated to the same degree as the reaction gas A by the ribbon heater 12 to reliquefy the reaction gas A in the same manner as in Example 1 above. Is prevented.

Embodiment 3 Next, FIG. 3 is a sectional view showing the principal part of a chemical vapor deposition apparatus according to still another embodiment of the present invention. In the figure, 13 is a band heater as a cooling preventing means which is provided on the outer peripheral portion of the partition plate 6 in the gas head 4 having a double structure and which heats the partition plate 6.

In the chemical vapor deposition apparatus of Example 3, the inert gas B is introduced at room temperature, but the temperature of the partition plate 6 is monitored by the thermocouple 14 while the temperature of the partition plate 6 is controlled by the band heater 13. By keeping the reaction gas A at the same level as that of the reaction gas A, the heat of the reaction gas A is prevented from being taken by the inert gas B through the partition plate 6. Therefore, the first embodiment described above
Similarly, the reliquefaction of the reaction gas A is prevented, and the reaction gas A
This liquid is prevented from remaining in the gas head 4 and the deposition rate of the reaction product film from decreasing.

In the third embodiment, the band heater 13 is provided on the gas head 4 having a double structure. However, in the gas head 4 having a multiple structure as shown in FIG.
The first partition plate 6a adjacent to the first partition plate 6a may be heated by the band heater 13. Further, in each of the above-described embodiments, the ribbon heater 12 and the band heater 13 are used as cooling prevention means.
However, the cooling prevention means is not limited to these.

[0021]

As described above, in the chemical vapor deposition apparatus of the present invention, the cooling preventing means prevents the reaction gas from being cooled by the inert gas, so that the reaction gas in the gas head can be prevented. Reliquefaction can be prevented, the liquid of the reaction gas can be prevented from remaining inside the gas head, and the deposition rate of the reaction product film can be reduced, thus ensuring stable film formation. There is an effect that can be done.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts of a chemical vapor deposition apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of essential parts of a chemical vapor deposition apparatus according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view of essential parts of a chemical vapor deposition apparatus according to still another embodiment of the present invention.

FIG. 4 is a cross-sectional view of essential parts showing an example of a conventional chemical vapor deposition apparatus.

[Explanation of symbols]

 1 Semiconductor Wafer 2 Wafer Stage 3 Reaction Chamber 4 Gas Head 4A Reactive Gas Part 4B Inert Gas Part 4Ba First Inert Gas Part 5A Reactive Gas Outlet 5B Inert Gas Outlet 5Ba First Inert Gas Outlet 9 Reactive gas introduction pipe 10 Inert gas introduction pipe 10a First inert gas introduction pipe 12 Ribbon heater (cooling prevention means) 13 Band heater (cooling prevention means)

Claims (1)

[Claims] 1. A reaction chamber, a wafer stage which is provided in the reaction chamber and holds a semiconductor wafer, and a plurality of reaction gas blowout ports located in the central portion and facing the wafer stage and located in the outer peripheral portion. A gas head having a plurality of inert gas outlets, and the inside of which is separated into a reaction gas portion and an inert gas portion, and a reaction gas introduction pipe for introducing a reaction gas into the reaction gas portion. And an inert gas introducing pipe for introducing an inert gas into the inert gas portion, and preventing the reaction gas in the reaction gas portion from being cooled by the inert gas introduced into the inert gas portion. And a cooling prevention means for controlling the chemical vapor deposition.