JPH0245931A - Plasma vapor growth device - Google Patents

Abstract

PURPOSE:To enable a refractive index of a thin film to be uniform by providing a damper at a plurality of discharge holes connected to a main discharge hole or two discharge holes opposing the main discharge hole. CONSTITUTION:Eight discharge boles 12 are provided at a reaction room 13 and are connected to main discharge holes 15 at four places each (left and right sides). A semiconductor wafer is retained and stored in a semiconductor wafer susceptor 14 in the reaction room 13, a reaction gas is introduced from a reaction gas guiding system, and plasma is generated to form a thin film on the semiconductor wafer. A damper 16 whose opening can be adjusted is provided at each discharge hole 12 and the opening can be adjusted to 25%, 50%, 75% and 100% from a location closer to the main discharge hole 15. It allows the fluid of each discharge hole to be adjusted, thus enabling the refractive index of thin film to be uniform. Also, two main discharge holes are provided opposing each other instead of a damper for achieving intermittent switching.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a plasma vapor phase growth apparatus used for manufacturing semiconductor devices, etc., and particularly to the structure of its exhaust system.

[Conventional technology]

In the exhaust structure of a conventional plasma vapor phase growth apparatus, as shown in FIG. 4, eight exhaust holes 12 are provided in the reaction chamber 13, and four exhaust holes on the left and right are connected to one main exhaust hole 15. was. In the reaction chamber 13, 11 semiconductor wafers numbered 1 to 11 are held in a susceptor 14, and a reaction gas is introduced from a reaction gas introduction system (not shown) to the susceptor 14 and the electrode plate below it. A high frequency is applied during this time to generate plasma and form a thin film on the semiconductor wafer.

[Problem to be solved by the invention]

The exhaust structure of the conventional plasma vapor phase growth apparatus described above does not have a damper in the exhaust hole, so when forming a nitrogen oxide film on a wafer, for example, the main exhaust hole 1
The exhaust hole that is close to the main exhaust hole has a high flow rate and the reaction gas is easily exhausted, and since the decomposition rate of N20 is slower than that of SiH4 and NH, N20 is more likely to contribute to the reaction on the main exhaust hole side, and the reaction gas is easily exhausted. The refractive index was lowered, and the refractive index distribution within the disposed wafer was worsened.

[Means to solve the problem]

The present invention provides a plasma vapor phase growth apparatus having an exhaust structure in which a reaction chamber has a plurality of exhaust holes and these exhaust holes are connected to a main exhaust hole, in which dampers are provided in the plurality of exhaust holes, or Alternatively, it is characterized by having two main exhaust holes facing each other.

〔Example〕

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

FIG. 1 is a plan view of a first embodiment of the reaction chamber exhaust structure of the present invention. The exhaust structure is the same as the conventional one shown in FIG. 4 described above, but in this embodiment, a damper 16 is installed in each exhaust hole 12 so that each opening can be adjusted. Inside the reaction chamber 13 there is a susceptor 14 into which 11 silicon wafers can be inserted.
A high frequency wave is applied between the wafer and the electrode plate located below to generate plasma from the introduced reactive gas, forming a thin film on the wafer.

Next, in order to confirm the effects of the present invention, in a plasma vapor phase growth apparatus having the exhaust structure shown in FIGS.
A nitrogen oxide film was grown on a silicon wafer using reactive gases of H4, NH3, and N20, and the refractive index of 11 wafers was measured. In this experiment, the damper opening degrees of the exhaust holes 12 in FIG. 1 were set to 25%, 50%, 75%, and 100% from the side closest to the main exhaust hole 15. The results are shown in FIG. As you will see, in the conventional exhaust structure, the refractive index gradually increases from wafer numbers 1 to 11, and the variation in refractive index within the wafers is 0.
It is 91%. In contrast, in the exhaust structure of the present invention, the refractive index distribution within the wafer is flat, and the variation is 0.20%, which is significantly improved compared to the conventional structure.

FIG. 2 is a plan view of a second embodiment of the present invention. In this embodiment, a damper is not provided in the exhaust hole, and there are two systems of main exhaust holes, front and rear, and the main exhaust hole 15 is intermittently closed during the reaction time. By switching the main exhaust hole 17 and the main exhaust hole 17, the same results as in the first embodiment were obtained.

〔Effect of the invention〕

As explained above, the present invention can improve the refractive index of the thin film grown by providing a damper in the exhaust hole of the reaction chamber to adjust the opening degree, or by providing two main exhaust holes and switching intermittently. This has the effect of improving the uniformity between wafers.

Ri3ro

[Brief explanation of the drawing]

Fig. 1 is a plan view of the first embodiment of the present invention, Fig. 2 is a plan view of the second embodiment of the invention, and Fig. 3 shows the refractive index distribution in the inventive and conventional exhaust structures. The figure shown in FIG. 4 is a plan view of an exhaust structure of a conventional plasma vapor phase growth apparatus. 1-11... Semiconductor wafer, 12... Exhaust hole, 1
3... Reaction chamber, 14... Susceptor, 15.17.
...Main exhaust hole, 16...To damper or 1 1.! Ritsu: 1-1-111 4 causes of heat

Claims (1)

[Claims] In a plasma vapor deposition apparatus equipped with an exhaust structure in which the reaction chamber has a plurality of exhaust holes and these exhaust holes are connected to a main exhaust hole, dampers are provided in the plurality of exhaust holes or the main exhaust hole is connected to the main exhaust hole. A plasma vapor phase growth apparatus characterized in that two are provided facing each other.