Sharp Kabushiki Kaisha Corporation

Hisashi Yonemoto

Masayuki Tajiri

Toyohiro Harazono

Takayoshi Hashimoto

Satoshi Hikida

Takuya Otabe

A formation method of an element isolation film according to which a high-voltage transistor with an excellent characteristic can be formed is provided. On a substrate, a gate oxide film is previously formed. A CMP stopper film is formed thereon, and thereafter, a gate oxide film and a CMP stopper film are etched. The semiconductor substrate is etched to form a trench. Further, before the trench is filled with a field insulating film, a liner insulating film is formed at a trench interior wall, and a concave portion at the side surface of the gate oxide film under the CMP stopper film is filled with the liner insulating film. In this manner, formation of void in the element isolation film laterally positioned with respect to the gate oxide film can be prevented.

Semiconductor device manufacturing method and semiconductor device

A formation method of an element isolation film according to which a high-voltage transistor with an excellent characteristic can be formed is provided. On a substrate, a gate oxide film is previously formed. A CMP stopper film is formed thereon, and thereafter, a gate oxide film and a CMP stopper film are etched. The semiconductor substrate is etched to form a trench. Further, before the trench is filled with a field insulating film, an liner insulating film is formed at a trench interior wall, and a concave portion at the side surface of the gate oxide film under the CMP stopper film is filled with the liner insulating film. In this manner, formation of void in the element isolation film laterally positioned with respect to the gate oxide film can be prevented.

The high-withstand voltage MOSFET comprises a trench portion formed at the high-withstand voltage active region on a semiconductor substrate, two polysilicon layers formed on the high-withstand voltage active region on both sides of the trench portion by implanting an impurity of the conductivity type opposite to the high-withstand voltage active region, two impurity diffusion drift layers formed on both sides of the trench portion by implanting an impurity of the conductivity type opposite to the high-withstand voltage active region in the surface of the high-withstand voltage active region under the polysilicon layers, and a gate electrode formed through a gate oxide film on bottom and side surfaces of the trench portion and end surfaces and upper surfaces of adjacent regions of the polysilicon layers close to the trench portion, and source and drain regions are formed in the two polysilicon layers excluding the adjacent regions covered with the gate electrode.

Growing community of inventors

Osaka, Japan

Hisashi Yonemoto