JPS622544A - Noiseless discharge type gas plasma treating device - Google Patents

Abstract

PURPOSE:To obtain uniform plasma to uniformize the film thicknesses of the CVD films being formed on the matters to be treated and the amount of plasma etching by a method wherein at least one side of the plasma generating electrodes is coated with a dielectric and AC voltage is impressed across both the electrodes. CONSTITUTION:Flat plate type electrodes 12 are each coated with a dielectric 10, such as glass and ceramics, a hotplate 3 is set up in the vicinity of a heater 4 and matters 5 to be traeted are set up on the upper surface thereof. An AC power source 9 is connected between the hotplate 3 and the flat plate type electrode 12 on one side and the reaction gas to be fed from a reaction gas feeder 7 is fed in a reaction chamber 13 through a gas feed opening 11. When discharge is caused in such a device, discharge plasma is specially produced uniformly and uniform plasma exists even in the vicinities of the matters to be treated. In particular, uneven plasma is not produced at all even at the ends of the electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a silent discharge type gas plasma processing apparatus having an electrode structure capable of uniformly producing a plasma-generated film or etching amount.

[Technical background of the invention and its problems]

In the conventional gas plasma processing apparatus, as shown in FIG. 3, a power source 2 is connected to a circular plate-shaped electrode 1 divided into five parts, a hot plate 3 is heated by a heating element 4, and a hot plate 3 is placed on top of the electrode 1. The processed object 5 is processed. Gas is temporarily supplied into the bell jar 6 from a gas supply body 7, and residual gas is exhausted by a residual gas exhaust body 8. Visit hot plate 3
is processed while being rotated by the rotary drive body 9. Such a technique is also described in Japanese Patent Publication No. 59-33250.

This plasma generating electrode 1 consists of five disk-shaped plates.
It is divided into parts. Therefore, the plasma inevitably becomes spatially non-uniform, and the density of the reactive gas in contact with the object to be processed becomes non-uniform, resulting in non-uniform film thickness of the processed film (OVD film). Particularly, the non-uniformity is remarkable at the electrode end.

The same holds true for plasma etching; the etching rate is slow on average due to plasma non-uniformity, resulting in a long processing time. In addition, the hot plate 3 on which the object to be processed 5 is placed is rotated by a rotary drive member 9, and the object to be processed is rotated, but the device is complicated, large in size, and expensive, and has many drawbacks. .

[Purpose of the invention]

In the present invention, at least one of the plasma generating electrodes is covered with a dielectric material and an alternating current voltage is applied between the electrodes to obtain uniform plasma, thereby making the OVD film thickness and plasma etching amount uniform. The purpose of the present invention is to provide a silent discharge type gas plasma processing apparatus with high performance.

[Summary of the invention]

In the present invention, in order to realize spatial uniformity of discharge plasma, discharge is essentially non-uniform with one electrode. Particularly when the gas pressure is high, non-uniform plasma is likely to be generated.

A discharge type that achieves uniform discharge at any gas pressure is a so-called silent discharge, which is generated by interposing a dielectric between electrodes and applying alternating current. This silent discharge is equivalent to having countless small capacitance capacitors connected between the discharge power source and the discharge power source because a dielectric material is present between the electrodes, so that a spatially uniform discharge is generated. The present invention utilizes the characteristics of this discharge.

〔Effect of the invention〕

According to the present invention, it is possible to obtain spatially uniform plasma, and therefore the amount of reactive gas that comes into contact with the object to be processed is uniform, achieving uniform 0VD film thickness and uniform plasma etching amount. As a result, improved processing power is achieved. Furthermore, the device becomes simpler, smaller, and cheaper.

[Embodiments of the invention]

FIG. 1 shows a silent discharge type gas plasma processing apparatus of the present invention. In this device, parts that are the same as those used in the prior art will be described using the same reference numerals. 12 is a flat electrode, on which a dielectric material 10. For example, it is coated with glass, ceramics, etc.

A hot plate 3 is installed near the heated heater 4, and an object 5 to be processed is placed on the top surface of the hot plate 3. hot plate 3
An AC power source 9 is connected between the electrode 12 and the flat electrode 12 .

Further, the reaction gas supply body 7 supplies gas to the reaction chamber through the gas supply hole 11 . Further, the gas supply holes 11 were provided around the reaction chamber 13, and in this apparatus, they were provided at eight locations. (Omitted from the figure) When a discharge is generated in such an apparatus, discharge plasma is generated spatially uniformly, and uniform plasma exists even in the vicinity of the object to be processed 5. In particular, no non-uniform plasma is generated even at the electrode ends. In the example, a Si film was formed on a quartz substrate. When the temperature is kept at 100 to 150° C. on a hot plate and a silent discharge is generated using Sin as a gas supply, a Si film is uniformly formed on the quartz substrate by plasma CVD. Furthermore, even if the pressure was increased to several Nator, the discharge plasma remained uniform and the deposition rate of the produced film tended to increase.

As described above, by using the silent discharge type plasma processing apparatus of the present invention, the OVD film thickness and the amount of plasma etching can be made uniform, and the apparatus can be made simple, compact, and inexpensive.

In this embodiment, a flat plate electrode is used covered with a dielectric, but a mesh-like metal electrode may be embedded in the dielectric, for example. Further, even if a highly heat-resistant insulator 14 such as ceramics is placed and used on the hot plate as shown in FIG. 2, a similar silent discharge is generated and the same effect as described above can be obtained.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of the configuration of a silent discharge type gas plasma processing apparatus according to an embodiment of the present invention, Fig. 2 is a schematic diagram of the configuration of another modification of the present invention, and Fig. 3 is a schematic diagram of the configuration of a conventional capacitor shop gas plasma processing apparatus. A schematic diagram of the configuration is shown. DESCRIPTION OF SYMBOLS 12... Flat plate electrode, 10... Dielectric material, 5... Treated object, 3... Hot plate, 9... AC power supply. Agent Patent Attorney Kensuke Chika (and 1 other person) No.
1 Figure 2

Claims (1)

[Claims] A silent discharge type gas plasma processing apparatus characterized in that at least one of the two electrodes is an electrode covered with a dielectric material, and an alternating current voltage is applied between the electrodes.