Adhesive bonding and miscellaneous chemical manufacture – Differential fluid etching apparatus – With microwave gas energizing means
Patent
1996-05-31
1998-08-04
Powell, William
Adhesive bonding and miscellaneous chemical manufacture
Differential fluid etching apparatus
With microwave gas energizing means
216 69, 438726, H01L 2100
Patent
active
057887985
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a plasma processing apparatus which is suitable for carrying out the etching, ashing and CVD processes by using plasma on semiconductor device substrates, glass substrates for liquid crystal display (LCD) panels, and the like.
BACKGROUND ART
Plasma of reactive gas is used widely in the fabricating process of LSI and LCD devices. Particularly, the dry etching technique using plasma is an indispensable fundamental technique for the fabricating process of LSI and LCD devices.
As excitation means for generating plasma, the RF (high frequency) of 13.56 MHz is often used, and the microwave is also used recently. This is attributable to the advantages of the generation of low temperature and high-density plasma and the simplicity of the structure and operation of the apparatus.
However, it is difficult for plasma processing apparatus using the microwave to generate uniform microwave plasma over a large area, and therefore it is difficult to process large semiconductor substrates and LCD glass substrates uniformly.
In regard to this matter, the applicant of the present invention has proposed a scheme of using a dielectric sheet for a plasma processing apparatus that is capable of producing uniform microwave plasma over a large area, as disclosed in Japanese Patent Application Laid-Open No. 62-5600 and No. 62-99481.
FIG. 1, FIG. 2 and FIG. 3 are a schematic plan view, a partial cross-sectional view along the line A--A, and a partial cross-sectional view along the line B--B, respectively, of the plasma processing apparatus having the dielectric sheet proposed in the above-mentioned patent publication.
In the plasma processing apparatus shown in these figures, the microwave generated by a microwave generator 26 is directed by a microwave guide path 23 into a dielectric sheet 21. The microwave propagated in the dielectric sheet 21 forms an electric field in a hollow area 20 beneath it. The electric field penetrates a microwave window 4 and enters a reaction room 2, in which reactive gas is excited and plasma is generated. By the generated plasma, the surface of a sample S is subjected to the plasma processing.
The dielectric sheet 21 consists of an entry section 211, a fan-tailed section 212 and a flat section 213. The microwave is led from the microwave guide path 23 into the dielectric sheet 21 as follows. At the entry section 211, the microwave is led from the waveguide into the dielectric sheet. It is expanded in the transverse direction in the fan-tailed section 212. The expanded microwave is led into the flat section 213. Based on this structure, the microwave can be propagated with a uniform transverse distribution in the large flat section 213.
The plasma processing apparatus having this dielectric sheet enables the microwave to propagate uniformly to the large flat section 213, and by widening the microwave window 4 and microwave lead-in opening 3 which confront the flat section 213, it is possible to generate microwave plasma of large area in the reaction room 2.
In recent years, large glass substrates are used for LCD panels, and there are intense demands for apparatus that are capable of uniformly processing glass substrates of 400-by-400 mm or larger. Plasma processing apparatus having this dielectric sheet can generate large-area plasma by having a large dielectric sheet, microwave window and microwave lead-in opening, as mentioned above.
However, when the area of the dielectric sheet is increased steadily, the following problem will emerge. If the dielectric sheet has its width widened too much, with the fan-tailed section 212 being unchanged in length, the dielectric sheet of the fan-tailed section fans out at a large angle in the transverse direction. Therefore, the microwave cannot be expanded uniformly in the transverse direction of the dielectric sheet, resulting in a weak electric field of the microwave at the ends in the transverse direction of the dielectric sheet and an uneven distribution of plasma in the transverse direction of the dielectr
REFERENCES:
patent: 5415719 (1995-05-01), Akimoto
International Search Report.
Ebata Toshiki
Kanayama Shuta
Komachi Kyoichi
Mabuchi Hiroshi
Matsumoto Naoki
Powell William
Sumitomo Metal Industries Ltd.
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