Fujitsu Corporation

Kazumasa Doi

Masanori Onodera

Eiichi Hoshino

Kazuhiko Sumi

Naoyuki Ishiwata

Mitsufumi Naoe

A transparent optical device is provided with a transparent medium having a front side, at least a portion of the front side being adapted for receiving light. A porous layer is formed on substantially all areas of the front side which are adapted for receiving light. The transparent optical device may have a recessed surface area which is recessed below a remainder area of the front side to define a phase shift photomask. The transparent medium may be made of synthesized silica. The porous layer may be formed by reactive ion etching using gaseous plasma of halogenized hydrocarbon. The front side of the transparent medium may have a portion not adapted for receiving light which may have a metal pattern formed thereon. In producing the transparent optical mask, the porous layer may be formed before or after the metal pattern. The transparent optical device may be formed in an etching chamber in which etching depth is monitored by measuring the transmissivity of a preselected portion of the transparent medium.

Transparent optical device and fabrication method thereof

A method for manufacturing a phase shift mask of the invention comprises a process of protecting a side wall of an opening in a light-damping film by means of a resist and then etching the light-damping film to be so thin as a halftone film.

Growing community of inventors

Kawasaki, Japan

Kazumasa Doi