Renesas Technology Corp.

Kenichi Ohto

Takashi Terauchi

Shuichi Ueno

Shigeru Shiratake

Hiroshi Umeda

Yukio Nishida

Akinori Kinugasa

An alignment mark section on a semiconductor substrate has two grooves which are filled with silicon oxide. The surface of the portion of the semiconductor substrate sandwiched by these grooves is lower than other portions of the semiconductor substrate to produce a step having a predetermined depth in the alignment mark section.

Method for manufacturing semiconductor device

A smile oxide film, serving as a gate oxide film, is formed under a three-layer poly-metal gate consisting of a doped polysilicon layer, a tungsten layer, and a SiON layer. The smile oxide film has a first region located beneath an edge of the poly-metal gate and a second region located beneath a central portion of the poly-metal gate. A film thickness of the first region is larger than a film thickness of the second region. An anti-oxidizing film, having a small oxygen diffusion rate compared with the polysilicon layer, entirely covers the poly-metal gate without exposing.

MOSFET with graded gate oxide layer

Growing community of inventors

Tokyo, Japan

Kenichi Ohto