The present invention relates to a plasma processing method of a minute portion.
In general, when an object to be processed represented by a substrate on the surface of which a thin film is formed is subjected to a patterning process, a resist process is used. One example of the process is shown in FIGS. 9A through 9D. In FIGS. 9A through 9D, first of all, a photosensitive resist 34 is coated on the surface of an object 33 to be processed (FIG. 9A). Next, by carrying out exposure by means of an exposure apparatus and thereafter carrying out development, the resist 34 can be patterned into the desired shape (FIG. 9B). Then, by placing the object 33 to be processed in a vacuum vessel, generating a plasma in the vacuum vessel and subjecting the object 33 to be processed to an etching process using the resist 34 as a mask, the surface of the object 33 to be processed is patterned into the desired shape (FIG. 9C). Finally, by removing the resist 34 by means of an oxygen plasma, an organic solvent, or the like, the processing is completed (FIG. 9D).
The aforementioned resist process, which has been suitable for accurately forming a minute pattern, has come to play an important role in manufacturing electronic devices such as semiconductors. However, there is a drawback that the process is complicated.
Accordingly, there is examined a new processing method that uses no resist process. As one example, there is being proposed a plasma processing apparatus equipped with a microplasma source 99 as shown in FIG. 16. The construction is proposed in detail in, for example, the first patent reference of the company's own application that has been published as Japanese Unexamined Patent Publication No. 2004-146773 which was filed as claiming priority of Japanese Patent Application No. 2002-254324.
However, in the plasma processing proposed as above, if a high-frequency power is increased to increase an etching rate, arc discharge (spark) is generated on the surface of the thin plate as the object to be processed, and this leads to an issue that no smooth processed surface can be obtained and neither stability nor reproducibility of processing can be obtained.