Renesas Electronics Corporation

Photonics Electronics Technology Research Association

Atsuro Inada

Shinichi Watanuki

Akira Mitsuiki

Tsuyoshi Horikawa

Keizo Kinoshita

Tohru Mogami

Kazuhiko Ueno

First, half etching is performed to a semiconductor layer formed on an insulating layer to form trenches at positions of slab-portion regions in which slab portions are to be formed. After filling the trenches with an insulating film, a resist mask which covers the semiconductor layer at a projecting-portion region in which a projecting portion is to be formed and whose pattern ends are located on upper surfaces of the insulating films is formed on upper surfaces of the semiconductor layer and the insulating film, and full etching is performed to the semiconductor layer with using the resist mask and the insulating film as an etching mask, thereby forming an optical waveguide constituted of the projecting portion and the slab portions. Thereafter, a first interlayer insulating film is formed to cover the optical waveguide.

Semiconductor device and manufacturing method thereof

When an optical waveguide is formed, an area of an opening of a resist mask is equal to an area of a semiconductor layer for a dummy pattern exposed from the resist mask, and the semiconductor layer for the dummy pattern exposed from the resist mask has a uniform thickness in a region in which the dummy pattern is formed. As a result, an effective pattern density does not change in etching the semiconductor layer for the dummy pattern, and accordingly, it is possible to form a rib-shaped optical waveguide having desired dimensions and a desired shape.

Semiconductor device and method for manufacturing the same

A semiconductor substrate, an insulating layer made of silicon oxide formed on the semiconductor substrate and a semiconductor layer made of silicon formed on the insulating layer are provided, and the semiconductor layer constitutes an optical waveguide in an optical signal transmission line section and an optical modulator in an optical modulation section. Also, the insulating layer is removed except for a part thereof to have a hollow structure with a cavity, and both side surfaces and a lower surface of each of the semiconductor layers constituting the optical waveguide and the optical modulator are exposed and covered with air.

An etching stopper film is formed over a first insulating film. Then, a second insulating film is formed with a thickness that allows concave and convex portions formed due to a first gate electrode to remain. Then, anisotropic etching is performed using the etching stopper film as a stopper to remove the second insulating film over a second gate electrode and form a first side wall spacer of the first gate electrode. Then, the etching stopper film is removed. Then, anisotropic etching is performed on the first insulating film to form a second side wall spacer over the second gate electrode and form a third side wall spacer which is disposed inside the first side wall spacer over the first gate electrode.

Method of forming side wall spacers for a semiconductor device

The wafer processing apparatusincluded in an etching apparatus selectively etches the peripheral portion of a wafer. The wafer processing apparatusincludes a lower electrodeas a stage on which the waferis placed, a process gas introducing ductsupplying therethgouh a process gas etching the peripheral portion, an etching-interfering gas introducing ductsupplying therethrough an etching-interfering gas interfering supply of the process gas to the center portion of the wafer, and a movable alignment mechanismaligning the wafer on the lower electrode. The etching-interfering gas introducing ductand the process gas introducing ductcan be provided in an upper electrode

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Ibaraki, Japan

Atsuro Inada