JPH0590939U - Plasma CVD equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] In a plasma CVD apparatus, a stable reaction gas flow is generated and uniform plasma discharge is performed even when a large-sized substrate is formed, and moreover, controllability of plasma reaction is improved and thin film To improve the uniformity of film thickness and film quality distribution. [Structure] A flat plate-shaped high-frequency electrode and a ground electrode, which face each other, are provided in a reaction chamber in a vacuum atmosphere containing a predetermined reaction gas, and a high-frequency voltage is applied between both electrodes to generate glow discharge. In a plasma CVD apparatus for generating at least one of the components of the reaction gas as an amorphous thin film on the substrate held by the first electrode, the first electrode 4 on which the substrate 7 is mounted, and the first electrode Second electrode 1 facing 4
1 and a reaction gas introduction hole 1 formed in the second electrode 11
2 and a gas discharge hole 13 arranged in proximity to the reaction gas introduction hole 12.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a plasma CVD apparatus used for forming a thin film such as an amorphous silicon film or a silicon nitride film.

[0002]

[Prior Art]

 Heretofore, as a technique in such a field, for example, "Production Reactor for Low Temperature Plasma-Enhanced Silicon Nitride Deposition" has been published. State technology ”(Solid State Technology / June 1976, p. 45).

FIG. 4 is a schematic configuration diagram of such a conventional plasma CVD apparatus. In this figure, the reaction gas selected according to the type of thin film to be formed is introduced from the gas supply port 1 into the reaction vessel 10 placed under a reduced pressure of 0.01-1.0 Torr, and the reaction is performed. The finished gas is appropriately discharged to the outside through the gas discharge port 2.

In addition, the upper electrode 3 is arranged in the upper portion of the reaction vessel 10, and the substrate 7 as the object to be processed is provided below the substrate 7 as opposed to the upper electrode 3. Is placed on the substrate table 4 which serves as the lower electrode. A high-frequency voltage of about 10 kHz to 14 MHz is applied between the electrodes 3 and 4 to generate a high-frequency voltage inside the reaction gas, and at the same time kinetic energy is applied to the plasma to apply the kinetic energy to the substrate 7 to be processed. Plasma is made to collide and a thin film formation reaction is advanced. The substrate 7 can be heated and held from the outside of the reaction vessel 10 to a predetermined temperature, for example, a substrate temperature of about 300 ° C., by the heater 5.

[0005]

[Problems to be solved by the device]

 However, when various thin films are formed using the plasma CVD apparatus in the prior art, it becomes difficult to form a film uniformly over the entire substrate when the substrate to be processed becomes large. The main causes are considered as follows.

The reaction gas flow becomes non-uniform. The plasma discharge becomes non-uniform due to the shape of the electrodes. Specifically, in FIG. 4, the reaction gas is discharged from the periphery of the electrode, but when the electrode becomes large, the reaction gas stagnates in the central part of the electrode, and the concentration, components, etc. of the reactive gas in the central part of the electrode and the surroundings. It will be different. Therefore, the film formed on the substrate becomes non-uniform.

Further, in the parallel plate type electrode, when the size of the electrode is increased, it becomes difficult to obtain sufficient flatness of the electrode and uniformity of the distance between the electrodes. For example, if the electrode is partially distorted, an abnormal discharge will occur at that part. The above two points are the main causes of the non-uniformity of the film, but the above is a problem of processing accuracy and can be solved by improving the processing accuracy.

However, the above cannot be fundamentally solved if the structure of the electrode is as it is. The present invention eliminates the above problems, can generate a stable reaction gas flow even when forming a large-sized substrate, can obtain a uniform plasma discharge, and can improve the controllability of the plasma reaction. At the same time, it is an object of the present invention to provide a plasma CVD apparatus capable of improving the uniformity of the film thickness and film quality distribution of a thin film.

[0009]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention has a flat plate-shaped high frequency electrode and a ground electrode facing each other in a reaction chamber in a vacuum atmosphere containing a predetermined reaction gas, and applies a high frequency voltage between both electrodes. In the plasma CVD apparatus for generating a glow discharge to generate at least one of the components of the reaction gas as an amorphous thin film on the substrate held by one electrode, the first electrode on which the substrate is placed. And a second electrode facing the substrate, a reaction gas introduction hole formed in the second electrode, and a gas discharge hole provided in the vicinity of the reaction gas introduction hole. It is a thing.

[0010]

[Action]

 According to the present invention, as described above, in the plasma CVD apparatus, the reaction gas introduction hole and the gas discharge hole are provided close to the electrode facing the substrate, and the same reaction gas flow is applied to the central portion and the peripheral portion of the electrode. By providing it, stable plasma can be generated and a uniform thin film can be formed.

[0011]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of a plasma CVD apparatus showing an embodiment of the present invention, FIG. 2 is a fragmentary perspective view of an electrode of a plasma CVD apparatus showing an embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. It is a top view of the electrode of the plasma CVD apparatus shown. The same parts as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted.

As shown in these figures, a large-area display substrate 7 as an object to be processed is placed on a substrate stand (first electrode) 4 which serves as a lower electrode in the reaction vessel 10. A counter gas (second electrode) 11 as a high-frequency electrode that is placed and faces the counter electrode is provided with reaction gas introduction holes 12 and gas discharge holes 13 alternately adjacent to each other. That is, the reaction gas introduction holes 12 and the gas discharge holes 13 are alternately formed in the counter electrode 11 at equal intervals and in a grid pattern. A reaction gas introduction pipe 14 arranged in a lattice is connected to the reaction gas introduction hole 12, and the reaction gas introduction pipes 14 are collectively connected to the reaction gas introduction port 16.

Therefore, the reaction gas from the reaction gas introduction port 16 passes through the reaction gas introduction pipe 14 and enters the reaction container 10 through the gas introduction hole 12, and a high frequency of about 10 kHz-14 MHz between the substrate table 4 and the counter electrode 11. A high-frequency voltage is applied by the power source 6 to turn the internal reaction gas into plasma, and kinetic energy is applied to the plasma so that the plasma collides with the substrate 7 to be processed and the thin film formation reaction proceeds. . The substrate 7 can be heated and held by the heater 5 from the outside of the reaction vessel 10 to a predetermined temperature, for example, a substrate temperature of about 300 ° C.

The exhaust gas after the reaction is exhausted by a pump (not shown) through a gas exhaust pipe 15 through a gas exhaust hole 13 provided in the surface of the counter electrode 11 facing the substrate. The reaction gas introduction holes 12 are communicated with each other by a reaction gas introduction pipe 14 and are separated from the gas discharge holes 13. Here, since the reaction gas introduction hole 12 and the gas discharge hole 13 are installed all over to face the substrate, stagnation of the gas does not occur.

Incidentally, the electrode of the plasma CVD apparatus shown in FIG. 3 has an area of, for example, 50 cm × 50 cm, the reaction gas introduction hole 12 has a size of 0.5 to 0.8 mmφ, and the gas discharge hole 13 has a size of 2. ~ 4 mmφ. In addition, for example, SiH ₄ + NH ₃ (silane + ammonia) is introduced as a reaction gas into a 14 inch (35.56 cm) square glass substrate to deposit a silicon nitride Si ₃ N ₄ film on the glass substrate. SiH ₄ can be introduced as a reaction gas to deposit amorphous silicon.

Therefore, the concentration and quality of the existing reaction gas (plasma) are kept uniform between the parallel plate electrodes. Therefore, a uniform film can be formed regardless of the size of the electrode (substrate). The present invention is not limited to the above-mentioned embodiments, and various modifications can be made based on the spirit of the present invention, and these modifications are not excluded from the scope of the present invention.

[0017]

[Effect of the device]

 As described in detail above, according to the present invention, the reaction gas introduction hole and the discharge hole are provided in the electrode facing the substrate in close proximity to each other, so that the same quality (pressure, pressure, By providing a reactive gas flow having a density, etc., stable and uniform plasma can be generated regardless of the size of the electrode (substrate). Further, it is possible to form a uniform thin film despite the large area of the substrate.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a plasma CVD apparatus showing an embodiment of the present invention.

FIG. 2 is a fragmentary perspective view of an electrode of a plasma CVD apparatus showing an embodiment of the present invention.

FIG. 3 is a plan view of electrodes of a plasma CVD apparatus showing an embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a conventional plasma CVD apparatus.

[Explanation of symbols]

 4 substrate stand (lower electrode) 6 high frequency power supply 7 substrate 10 reaction vessel 11 counter electrode (high frequency electrode) 12 reaction gas introduction hole 13 gas discharge hole 14 reaction gas introduction pipe 15 gas discharge pipe 16 reaction gas introduction port

Claims (1)

[Scope of utility model registration request] 1. A flat plate-shaped high frequency electrode and a ground electrode, which face each other, are provided in a reaction chamber in a vacuum atmosphere containing a predetermined reaction gas, and a high frequency voltage is applied between both electrodes to generate glow discharge. A plasma CVD apparatus for producing at least one of the components of the reaction gas as an amorphous thin film on a substrate held by one electrode, (a) a first electrode on which the substrate is mounted; ) A second electrode facing the substrate, (c) a reaction gas introduction hole formed in the second electrode, and (d) a gas discharge hole provided in the vicinity of the reaction gas introduction hole. A plasma CVD apparatus comprising: