JPS62286218A - Chemical vapor growth method - Google Patents

Abstract

PURPOSE:To prevent the adhesion of substance fell on the surface of a wafer and to contrive to make uniform the temperature distribution of the wafer by a method wherein the wafer is separated from a susceptor and supported facing downward on the lower side of the susceptor, the susceptor is heated up, and the wafer is also heated by the radiant heat sent from the susceptor. CONSTITUTION:A pawl 8b, with which a wafer 1 is detachably supported, is provided on the lower surface of a thick plate-formed susceptor main body 8a, a susceptor 8 consisting of silicon carbide-coated graphite is prepared, said wafer 1 is supported facing downward and it is arranged in a reaction chamber 3. The wafer 1 is heated up by the radiant heat sent from the susceptor 8, the wafer comes in contact with reaction gas, and a deposited film 1a is formed on the surface of the wafer. As the wafer 1 is facing downward, the foregin substance 6 fell on the wafer is not adhered to the surface of the wafer 1. Also, as the heating of the wafer 1 is performed by the radiant heat sent from the susceptor 8, the temperature distribution of the wafer 1 can be made uniform even when the gap between the wafer and the susceptor 8 is not uniform, and the generation of a slip line 7 when the deposited film 1a is a crystal film can be prevented.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Summary] In chemical vapor deposition in which a reaction product is deposited on the wafer by supplying a reaction gas while heating the wafer supported by the susceptor, By supporting the wafer downward and away from the susceptor on the lower side, and by heating the susceptor so that the wafer is heated by radiant heat from the susceptor, it is possible to prevent falling foreign matter from adhering to the wafer surface and to reduce the temperature of the wafer. This aims to make the distribution uniform.

[Industrial application field]

The present invention relates to a chemical vapor deposition method in which a reaction product is deposited on a wafer by supplying a reaction gas while heating a wafer supported by a susceptor.

Chemical vapor deposition (CVD), as described above, is used to deposit semiconductors and insulators onto wafers in the manufacture of semiconductor devices and the like.

Therefore, during deposition, it is desirable to prevent foreign matter from being included in the deposited film and, if the deposited film is a crystalline film, to prevent crystal defects from occurring.

[Conventional technology]

A typical conventional method of chemical vapor deposition in which a reaction product is deposited on a wafer by supplying a reaction gas while heating a wafer supported by a susceptor is shown in the side view of FIG.

That is, the wafer 1 is placed directly on a susceptor 2 made of graphite coated with silicon carbide and placed in the reaction chamber 3 . A high frequency coil 4 is arranged outside the reaction chamber 3 to heat the susceptor 2 by induction.

Further, a reaction gas 5 is supplied from one side of the reaction chamber 3.

Then, the wafer 1 is heated by heat conduction from the susceptor 2 and comes into contact with the reaction gas 5, and reaction products are deposited on the surface to form a deposited film 1a.

[Problem that the invention seeks to solve]

However, in the above conventional method, the wafer 1 is
Since the wafer is oriented in the direction 1, floating foreign matter that has peeled off from the inner surface of the reaction chamber 3 falls onto the wafer 1, and as shown in the plan view of the wafer 1 in FIG.
There is a problem in that the quality of the deposited layer 1i1a is deteriorated due to the deposition of particles 1i1a.

Further, since the entire surface of the wafer 1 cannot be said to be in close contact with the susceptor 2, the temperature distribution is not necessarily uniform.

This temperature non-uniformity causes deposition 1j! When la is a crystalline film, it becomes a cause of generation of a slip line (SliρLine) 7 shown in FIG. 4, which is one of the crystal defects, and also causes a problem of deteriorating the quality of the deposited film 1a.

An improved method is to make the wafer 1 substantially vertical, but although this method is effective for the former problem, the latter problem still remains.

[Means for solving problems]

The above problem can be solved by the chemical vapor phase of the present invention in which the wafer support form is changed so that the wafer is supported downwardly and away from the susceptor under the susceptor, and the wafer is heated by radiant heat from the susceptor. Solved by growth method.

[Effect]

In the method of the present invention, since the wafer faces downward, the former problem mentioned above, that is, the problem of falling foreign matter adhering to the wafer surface, is solved.

Furthermore, since the wafer is heated away from the susceptor by radiant heat from the susceptor, even if the gap between the wafer and the susceptor is uneven, heat transfer from the susceptor to the wafer becomes uniform over the entire surface, resulting in a uniform temperature distribution. becomes uniform.

This solves the latter problem mentioned above, that is, the problem of slip lines.

〔Example〕

Examples of the method of the present invention will be described below with reference to FIGS. 1 and 2. The same reference numerals indicate the same functional objects throughout the figures.

FIG. 1 is a side view showing a first embodiment of the method of the present invention.

The method shown in this figure is a modification of the supporting form of the wafer 1 in the conventional method shown in FIG.

That is, a susceptor 8 made of graphite coated with silicon carbide is provided with claws 8b on the lower surface of a thick plate-like susceptor body 8a for supporting the wafer 1 at a distance, and the susceptor 8 is made to support the urchin 1 downward. It is placed in the reaction chamber 3. The arrangement of the high frequency coil 4 and the supply of the reaction gas 5 are the same as in the conventional method.

The wafer 1 is then heated by the radiant heat from the susceptor 8 and comes into contact with the reaction gas 5, resulting in a deposited film 1 on the surface.
form a.

In this method, since the wafer l is facing downward,
The fallen foreign matter 6 shown in FIG. 4 no longer adheres to the surface of the wafer 1. Furthermore, since the wafer 1 is heated by radiant heat from the susceptor 8, even if the gap between the wafer 1 and the susceptor 8 is uneven, the temperature distribution of the wafer 1 becomes uniform, and the deposited M1. If a is a crystalline film, the slip line 7 shown in FIG. 4 will not occur.

The present inventor has determined that the size of the susceptor body 8a is approximately 200 mm, the thickness is approximately 10 mm, and the gap between the susceptor body 8a and the wafer 1 is approximately 3 mm.
5 Q> When a deposited film of silicon crystals with a thickness of about 20 μm was formed on a silicon wafer using a susceptor 8 that supports the wafer, neither foreign matter 6 nor slip line 7 could be found in the deposited film. It was of good quality.

FIG. 2 is a side view showing a second embodiment of the method of the present invention.

The method shown in FIG. 1 is an extension of the method shown in FIG. 1 so that a plurality of wafers 1 can be processed simultaneously.

That is, the susceptor 9 used is the susceptor 8 shown in FIG.
It is made by arranging multiple pieces on a plane and integrating them. Then, a plurality of susceptors 9 supporting wafers 1 are stacked at intervals, the lowest stage is used as a dummy susceptor 10 that does not support wafer 1, and this block is placed in reaction chamber 3. Accordingly, the reaction chamber 3 and the high-frequency coil 4 are made larger, and the reaction gas 5 is supplied from above.

Although the dummy susceptor 10 does not require claws to support the wafer 1, it is desirable to match the material and size to the main body of the susceptor 9.

This method has the feature that the wafer 1 is heated from both sides, since the back surface of the next susceptor 9 faces the front side of the wafer 1 (the dummy susceptor 10 for the lowest wafer 1).

The present inventor has developed a susceptor 9 that supports four wafers 1 (
When the same deposited film as above was formed by stacking five susceptors (the thickness of the main body and the gap with the wafer 1 are the same as those of the susceptor 8) (the stacking pitch of the susceptor 9 is about 3011),
All deposited films were of good quality as before.

In the first embodiment, if it is desired to heat the wafer l from both sides, a dummy susceptor may be provided as in the second embodiment.

〔Effect of the invention〕

As explained above, according to the configuration of the present invention, during chemical vapor deposition in which a reaction product is deposited on the wafer by supplying a reaction gas while heating the wafer supported by a susceptor, foreign particles falling onto the wafer surface are removed. This has the effect of preventing the adhesion of foreign matter and making the temperature distribution of the wafer uniform, and making it possible to form a high-quality deposit with no foreign matter adhering to it and no slip lines being found in the crystal film.

[Brief explanation of drawings]

FIG. 1 is a side view showing the first embodiment of the method of the present invention, FIG. 2 is a side view showing the second embodiment of the method of the present invention, FIG. 3 is a side view showing a typical conventional method, and FIG. The figure is a wafer plan view showing the problems of the conventional method. In the figure, 1 is a wafer, 2.8.9 is a susceptor, 3 is a reaction chamber, 4 is a high frequency coil, 5 is a reaction gas, 6 is a falling foreign object, 7 is a slip line, and 10 is a dummy susceptor.

Claims (1)

[Claims] The wafer is supported downwardly and away from the susceptor under the susceptor, and while the susceptor is heated and the wafer is heated by radiant heat from the susceptor, a reaction gas is supplied to form a reaction product on the wafer. A chemical vapor deposition method characterized by depositing.