Mitsuo Saitoh

Fine pattern etching of molybdenum thin film and silicon substrate by using atmospheric line-shaped microplasma source

An atmospheric line-shaped microplasma source was developed for fine pattern etching. Observation of plasma emission of the developed plasma source has revealed that the finest plasma line is formed when helium (He) gas is supplied to the inner gas feed and reaction gas to the outer gas feeds. When reaction gas is supplied to the outer gas feeds, fluorine radical (F*) emission intensity increases with the gas flow rate, eventually exceeding the maximum emission intensity obtained when a mixture of reaction gas and He gas is supplied to the inner gas feed. Fine pattern etching of molybdenum thin film and silicon substrate was experimentally carried out using microplasma sources in two different configurations: one with the copper electrode covered to protect it from plasma exposure (type 1), and the other with the aluminum electrode end knife-edged and exposed to a plasma (type 2). The experiment revealed that the type 2 source provides a higher etching rate than of the type 1 source. The type 2 source can produce a fine etched pattern with lines of several ten to several hundred µm width. The maximum etching rate of silicon substrate is 79.0 µm/min.

Fine pattern etching of silicon substrates by using atmospheric line shaped micro plasma source

In this paper, various micro plasma sources have been proposed. We have already proposed two types of line shaped micro plasma sources. This report presents a new type of line shaped micro plasma source for finer processing than the former two types and its application to fine pattern etching of a silicon substrate.

Annealing performance improvement of elongated inductively coupled plasma torch and its application to recovery of plasma-induced Si substrate damage

The annealing performance of an elongated inductively coupled plasma (ICP) torch that enables instantaneous thermal processing over a large area has been improved by using a ceramic chamber that ensures better mechanical and thermal properties than a quartz chamber, realizing a substrate temperature higher than 1,600 K. Si wafers damaged by the bombardment of ions from Ar plasma were irradiated by the ICP torch for recovery. The thickness of the damaged layer was monitored by spectroscopic ellipsometry (SE), and the changes in Si crystal structure were examined by transmission electron microscopy (TEM). Significant decreases in damaged layer thickness and TEM contrast, which corresponds to the degree of damage, were observed after the ICP torch irradiation.

Fine pattern etching of molybdenum by using atmospheric line shaped micro plasma source

Various atmospheric micro plasma sources for maskless etching have been proposed. This report briefly summarizes the concept of our line shaped micro plasma source and presents fine pattern etching experiment of molybdenum thin film.