JPH0382779A - Plasma treating device - Google Patents

Abstract

PURPOSE:To keep good transparency of a quartz discharge tube and to treat a large-sized material with plasma by forming a discharge space in the discharge tube and evacuating the outside of the tube. CONSTITUTION:A microwave generated from a magnetron 9 is introduced into an evacuated treating chamber 1 through waveguides 6 and 8 to produce high- density plasma in the discharge tube 2 by the magnetic field of a coil 10. A bias power is impressed on a sample holder 3 from a high-frequency power source 4. Consequently, a wafer 5 on the holder 3 is efficiently executed an etching or the like. In this plasma treating device, a vacuum space 11 is formed outside the tube 2 in which a discharge space is formed. In this case, the waveguides 6 and 8 are arranged outside the tube 2, and the vacuum space 11 is preferably isolated by a quartz sheet 7 having a smaller diameter than the tube 2. The difference in the pressure between the inside and outside of the tube 2 is practically eliminated by this constitution, the thickness of the tube can be reduced to a necessary extent, and good transparency of the tube is kept even if the thickness of the wafer 5 is increased.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is plasma processing! The present invention relates to a J apparatus, and in particular to a plasma processing apparatus suitable for Ml, which generates plasma for etching, sputtering, CVD, etc. to process a sample.

[Conventional technology]

As for conventional plasma processing equipment, for example, Hitachi Hyoron
Vol, 71.45 (1989-5), pages 33 to 3
There is an apparatus discussed in "Dry etching apparatus" by Kawasaki et al., page 8. In this device, a quartz belljar is used as a member for laterally restricting the discharge chamber. In such a device, the transparency of the quartz belljar is used to collect light emitted from the plasma, making it possible to monitor the plasma.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not take into consideration the issue of increasing the size of the discharge space due to the increase in the diameter of the object to be processed. This requires a high thickness in terms of pressure resistance, and quartz has the problem of lowering its transparency and affecting the monitor.

An object of the present invention is to provide a plasma processing apparatus that can maintain good transparency of a quartz discharge tube even when the object to be processed becomes large.

[Means to solve the problem]

In order to achieve the above object, the outside of a quartz discharge tube that forms a discharge space inside is made into a vacuum region.

[For production]

By forming a vacuum region on the outside of the quartz discharge tube, atmospheric pressure is not applied to the quartz discharge tube as in conventional methods, and the thickness can be reduced to the extent necessary for processing, making it possible to maintain the same transparency as before. Therefore, the quartz discharge tube can be made suitable for large-diameter objects.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 9M1.

FIG. 1 shows a plasma processing apparatus, in this case a microwave etch apparatus. For microwave processing and etching processing, a quartz discharge tube 2 is provided at the top of a processing chamber 1 to form a vacuum processing chamber inside, and etching gas can be introduced from a gas source (not shown). , the pressure can be reduced by a vacuum evacuation device (not shown). A sample stage 3 serving as an electrode is provided in the processing chamber 1, and a high frequency power source 4 is connected to the sample stage 3. A wafer 5, which is an object to be processed, is placed on a sample stage 3. A waveguide 6 is provided on the outside of the discharge tube 2, and a coil 1 for generating a magnetic field is provided on the outside.
0 is the default. A quartz plate 7 is provided at the upper end opening of the waveguide 6.
A waveguide 8 is connected thereto, and a magnetron 9 is provided at the end of the waveguide 8.

In addition, although the space outside the discharge tube 2 formed by the waveguide 6, the quartz plate 7, and the discharge tube 2 is not shown in this case, an evacuation device that depressurizes and evacuates the inside of the processing chamber 1 is provided. A vacuum space U is formed by evacuating the space. Furthermore, when the inside of the processing chamber 1 is returned to atmospheric pressure during inspection or the like, leak gas can be supplied so that the space outside the discharge tube 2 is also returned to atmospheric pressure at the same time. This prevents the pressure difference between the inside and outside of the discharge tube 2 from becoming extremely different.

In the device configured in this manner, the microwaves emitted from the magnetron 9 pass through the waveguide 8 , pass through the quartz plate 7 , the inside of the waveguide 6 , and are supplied into the discharge tube 2 . This microwave and the magnetic field generated in the discharge tube 2 by the coil 10 create high-density plasma in the discharge tube 2, and by applying high frequency power to the sample stage 3, an appropriate bias voltage is applied to the wafer 5. is applied, ions in the plasma are drawn into the wafer 5, and reactive ion etching is performed.

At this time, since a vacuum chamber/space U is formed on the outside of the discharge tube 2, atmospheric pressure is not applied to the discharge tube 2 from the outside. Even if the inner diameter of the discharge tube 2 increases to 1 inch, there is no need to increase the thickness of the quartz, the discharge tube can be made thin, and the transparency will not deteriorate. As a result, even if a lighting section is provided outside the discharge tube 2, the light emitted from the plasma can be sufficiently illuminated, and the plasma can be monitored as before.

Further, atmospheric pressure is applied to the quartz plate 7, but since the area to which the pressure is applied is smaller than that of the discharge tube 2, the force is small and a thin quartz plate may be used. Therefore, in plasma monitoring, it is possible to collect light from the plasma even from the outside of the quartz plate 7, that is, from the atmosphere side.

As described above, according to this embodiment, the vacuum region is formed outside the discharge tube 2, so even if the wafer becomes larger and the discharge tube becomes larger, there is no need to increase the thickness of the discharge tube. ,
The transparency of the quartz discharge tube can be maintained.

In this embodiment, the case where the application is applied to a microwave ebutting apparatus has been described, but other kneeling apparatuses and sparter apparatuses using a quartz discharge tube are also applicable.

Needless to say, it can also be applied to CVD equipment and the like.

〔Effect of the invention〕

4. According to the present invention, even if the object to be treated becomes large, the transparency of the quartz discharge tube can be maintained at a good level.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a microwave etching apparatus which is an embodiment of the plasma processing apparatus of the present invention.

Claims (3)

[Claims] 1. A plasma processing apparatus using a quartz discharge tube forming a discharge space inside, characterized in that the outside of the front quartz discharge tube is a vacuum region. 2. 2. The plasma processing apparatus according to claim 1, wherein the discharge is caused by microwaves, and a waveguide for introducing the microwave is disposed outside the front quartz discharge tube, and the front waveguide and the front wave guide are arranged outside the front quartz discharge tube. A plasma processing apparatus in which a front vacuum region is formed between a quartz discharge tube and a quartz plate is provided at the microwave introducing portion of the front waveguide to isolate the front vacuum region. 3. 3. The plasma processing apparatus according to claim 2, wherein the diameter of the front quartz plate is smaller than the diameter of the front quartz discharge tube.