Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Katsuhiro Fujiyoshi

Hiroyuki Ishii

Toshikazu Tanioka

Kazuhiro Oka

Koichi Sakurai

Ayumu Onoyama

A silicon carbide semiconductor device includes an n-type epitaxial layer provided on a SiC substrate, a front surface electrode provided on the epitaxial layer, and a p-type electric field relieving region provided in the upper layer of the epitaxial layer in a terminal region. On the epitaxial layer, a first protective film composed of an interlayer insulating film and a protective oxide film that covers at least a part of the electric field relieving region is provided. A second protective film composed of a polyimide protective film is provided via a silicon nitride film so as to cover the outer end portion of the surface electrode, the first protective film, and at least a part of the epitaxial layer. The silicon nitride film protrudes from the second protective film at both an inner side end portion and an outer side end portion.

Silicon carbide semiconductor device and power conversion apparatus

Transforming optical images of a portion including a normal conductor pattern having a surface roughness, a portion subjected to an inspection, and a reference portion to images of electric charges and picking up these as electric signals by an image pick-up device, rendering the optical image including the normal conductor pattern having the surface roughness to a pixel signal by the image pick-up device, controlling a light volume of the optical image so that the pixel signal is saturated or immediately before the saturation, picking up a pixel signal of the portion to be inspected under this light volume, obtaining a differential signal from a pixel signal picked up from the reference portion, and judging an existence of defect from the differential signal, so as to detect defects such as a hiatus of conductor, a short circuit, and a deposition of an extraneous matter on a wafer, on which the normal conductor pattern having the roughened surface, with a high accuracy in processes of forming films and etching in manufacturing a semiconductor device.

Defect inspection method and defect inspection equipment

Growing community of inventors

Tokyo, Japan

Katsuhiro Fujiyoshi