JPH02105417A - Plasma vapor growth apparatus - Google Patents

Abstract

PURPOSE:To form a film having a uniform thickness on the surface of a wafer by a method wherein a wafer holder and a jig used to ground the wafer are installed at an upper-part electrode facing a lower-part electrode of a plasma vapor growth apparatus. CONSTITUTION:A water holder 15 is installed at an upper-part electrode 12 facing a lower-part electrode 13; a wafer 11 is set in such a way that a film- growth face is faced downward; after that, a jig 14 made on a metal is placed so as to be brought into contact with the upper-part electrode 12 and the wafer 11. An insulating film on the rear of the wafer 41 is removed. Thereby, the wafer 11 is grounded surely through the jig 14; an irregularity in a film thickness is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a plasma vapor phase growth apparatus, and particularly to a parallel plate type plasma vapor phase growth apparatus.

[Conventional technology]

There are two types of parallel plate type plasma vapor phase growth apparatus: a face-up method in which the film growth surface of the wafer faces upward, and a face-down method in which the film growth surface of the wafer faces downward.

As shown in FIG. 5, the face-up type reaction section has a structure in which a wafer 11 is placed on a lower electrode 13 with the film growth surface facing upward, and high-frequency power is supplied between it and the opposing upper electrode 12. It has become.

On the other hand, as shown in FIG. 4, in a face-down type reaction section, a wafer 11 is placed on the edge of a wafer holder 15 fitted with an upper electrode 12 with the film growth surface facing downward, and the wafer 11 is placed between it and the opposing lower electrode 13. The structure is such that it supplies high-frequency power to the In this case, the wafer holder 15 is made of the same metal as the upper electrode 12;
There is continuity with 2. In the face-down method, since the film growth surface faces downward, it is much more advantageous than the face-up method in terms of particle adhesion. In addition, in both types, the electrode side on which the wafer is placed is grounded, and the opposite electrode is connected to a high-frequency power source.

In FIGS. 4 and 5, 21 is an exhaust port, and 22 is a gas inlet.

[Problem to be solved by the invention]

As mentioned above, the face-down type vapor phase growth apparatus is very advantageous in terms of particle adhesion, but since the wafer 11 itself set in the wafer holder 15 also functions as a part of the electrode, it may be affected depending on the surface condition of the wafer. The plasma state between the wafer 11 and the counter electrode, that is, the plasma intensity differs. In other words, wafer 11
Since the upper electrode side where wafer 1 is set is grounded,
There is no problem if 1 is also grounded, but wafer holder 1
If the periphery of the wafer 11 that contacts the edge of the wafer 11 is covered with an insulating film, the wafer 11 will not be grounded and the wafer potential will float. Therefore, since high frequency power is not supplied to this portion, a film is grown only by the spread of plasma around the area. This has the disadvantage that the grown film will be thinner and the snow collection will be different than if the wafer 11 were grounded.

Also, the unibar 1 that comes into contact with the edge of the wafer holder 15
Even if the peripheral part of wafer 1 is a conductive film, normally the wafer 1
Since the entire surface of the wafer 1 is not covered with a conductive film, and furthermore, there is usually an insulating film on the surface of the wafer, the wafer itself is not grounded. Therefore, similarly grown films will be thinner and have different modifications.

[Means to solve the problem]

The plasma vapor phase growth apparatus of the present invention includes a lower electrode, an upper electrode provided opposite to the lower electrode, a wafer holder provided to the upper electrode, and a wafer held by the wafer holder that is grounded. It consists of a jig for

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a cross-sectional view of the vicinity of an electrode according to a first embodiment of the present invention.

In FIG. 1, a wafer holder 15 is provided on the upper electrode 12 provided opposite to the lower electrode 13. As shown in FIG. After setting the wafer 11 on the edge of the wafer holder 15 with the film growth surface facing downward, a metal jig 14 is placed so as to make contact with the upper electrode 12 and the wafer 11.

At this time, if an insulating film is attached to the back surface of the wafer 11, it is removed in advance.

In this way, according to the first embodiment, the wafer 11 is reliably grounded through the jig 14.

FIG. 3 is a diagram showing variations in film thickness when a silicon nitride (S i N) film is formed using the first embodiment and a conventional plasma vapor deposition apparatus.

As shown in Figure 3, when a jig to ground the wafer is not used, the variation in film thickness is extremely large, as shown by the broken line B, while when a jig is used, as shown by the solid line A. It can be seen that the variation in film thickness is extremely small.

FIG. 2 is a cross-sectional view of the vicinity of an electrode according to a second embodiment of the present invention.

In this second embodiment, instead of the jig 14 shown in FIG. 1, a metal disk 14A that is slightly thicker than the wafer is placed directly on the wafer 21, and the end of the metal disk 14A is placed on the wafer 21. It is designed to be brought into contact with the holder 15.

In this second embodiment, since the disk 14A directly serves as an electrode, the same effect as in the first embodiment can be obtained even if there is an insulating film on the back surface of the wafer 11.

〔Effect of the invention〕

As explained above, the present invention provides a plasma vapor phase growth apparatus that includes a lower electrode, an upper electrode provided opposite to the lower electrode, a wafer holder provided on the upper electrode, and a wafer held by the wafer holder. By including a jig for grounding, there is an effect that a film having a uniform thickness can be formed on the wafer surface.

[Brief explanation of drawings]

1 and 2 are cross-sectional views near the electrodes of the first and second embodiments of the present invention, FIG. 3 is a diagram showing the thickness of the SiN film formed by the embodiment and the conventional example, and FIG. 4 and FIG. 5 are cross-sectional views of a conventional example. 11... Wafer, 12... Upper electrode, 13...
Lower electrode, 4...Jig, 4A...Disc, 5...Wafer holder 0...Heater, 1...Exhaust hole,...Gas inlet.

Claims (1)

[Claims] a lower electrode, an upper electrode provided opposite the lower electrode, and a wafer holder provided on the upper electrode;
A plasma vapor phase growth apparatus comprising: a jig for grounding a wafer held by the wafer holder.