Plasma processing unit

Abstract

A plasma processing unit includes: a processing chamber (10); a first electrode (5) and a second electrode (11) which are placed in the processing chamber (10) and arranged to face each other; and a quartz plate (13) arranged on one of the surfaces of the first electrode (5) facing the second electrode (11) to protect the first electrode (5), the plasma processing unit being configured to excite reaction gas in the processing chamber (11) to generate plasma between the first electrode (5) and the second electrode (11) so that a target object placed on one of the surfaces of the second electrode (11) facing the first electrode (5) is subjected to plasma processing, wherein one of the surfaces of the quartz plate (13) facing the second electrode (11) is rough-finished.

Description

[0001] This application is a Continuation of International Application No. PCT / JP2005 / 010674, filed on Jun. 10, 2005. TECHNICAL FIELD [0002] The present invention relates to a plasma processing unit. BACKGROUND ART [0003] In the process of manufacturing electronic devices such as liquid crystal display devices and semiconductor devices, dry etching techniques have been widely used as a method for forming fine patterns. [0004] The dry etching techniques are required to achieve high aspect ratio, high etch rate, high selectivity and high uniformity. It is also required to prevent the occurrence of particles (fine-grained contaminants). [0005] The aspect ratio is the ratio of width to depth of a trace formed on a substrate by etching. The selectivity is the ratio between etch rate of a material to be etched and that of an etch mask material and an underlayer material. [0006] For example, if etching is carried out with low uniformity, the traces obtained by etching may suffer overetch (...

AI Technical Summary

Benefits of technology

[0029] According to the plasma processing unit of the present invention, one of the surfaces of the protection plate for protecting the first electrode facing the second electrode is rough-finished. This improves the heat absorbency of the protection plate, and therefore the reaction product is less likely to adhere to the protection plate. Further, the surface area of the one of the surfaces of the protection plate facing the second electrode is increased so that the protection plate is able to hold an increased amount of the reaction product adhered thereto. Therefore, the occurrence of particles due to the drop of the reaction product is less likely to occur. Moreover, since the reaction gas molecules generated by the plasma bounce from the rough-finished surface at various angles, the plasma processing is carried out uniformly. For these reasons, the occurrence of the particles is prevented easily and the plasma processing is carried out uniformly.

Problems solved by technology

For example, if etching is carried out with low uniformity, the traces obtained by etching may suffer overetch (excessive etching) and underetch (insufficient etching) due to the difference in etch rate.

Further, if a plurality of traces extending parallel to each other are formed by etching and the particles described above remain therebetween, a short may occur to reduce the manufacturing yield of the products.

This may possibly generate particles that contaminate the inside of the processing chamber.

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