The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 25, 2003
Filed:
May. 01, 2001
Toru Otsubo, Fujisawa, JP;
Tatehito Usui, Chiyoda, JP;
Hitach, Ltd., Tokyo, JP;
Abstract
A film formation monitor of a plasma CVD apparatus includes a light source for generating measuring light. Measuring light generated from the light source is guided to an optical system having lenses and mirrors, and is irradiated to a silicon substrate at a plurality of angles of incidence with the back of the silicon substrate being substantially a focus. Reflected light from the substrate is incident into a spectroscope. An intensity of measuring light is detected for each wavelength. A calculation apparatus calculates an etching depth. Reflected light from the back of the substrate interferes with reflected light from an etchd surface. To reduce influences of reflected light from the back of the substrate, measuring light is irradiated while its angle of incidence is varied.