Shin-etsu Handotai Co., Ltd.

Katsuaki Yoshizawa

Yoshinori Hayamizu

Masanori Mayuzumi

A silicon wafer is held in an airtight chamber by a silicon wafer holder. The silicon wafer holder is cooled by a cooler. High purity nitric acid is stored in a storage container disposed in the airtight container. The storage container is heated by a heater, thereby producing nitric acid gas. The nitric acid gas is condensed on the surface of the silicon wafer so that a thin film is formed. Thus, the surface of the silicon wafer is rendered hydrophilic. Thereafter, high purity hydrofluoric acid is dropped on high purity nitric acid in the storage container by an acid dropper, thereby producing hydrofluoric acid gas. By introducing the hydrofluoric acid gas into the thin film formed on the surface of the silicon wafer, an etching is performed while maintaining the surface of the silicon wafer in a good condition.

Growing community of inventors

Gunma-ken, Japan

Katsuaki Yoshizawa