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:
Feb. 02, 2021
Filed:
Oct. 24, 2019
Fuji Electric Co., Ltd., Kawasaki, JP;
Naoko Kodama, Matsumoto, JP;
FUJI ELECTRIC CO., LTD., Kawasaki, JP;
Abstract
A back alignment mark on a surface of a semiconductor substrate is detected and a resist mask patterned into a circuit pattern corresponding to a surface element structure is formed on a back of the semiconductor substrate. Detection of the back alignment mark is performed by using a detector opposing the back of the semiconductor substrate and measuring contrast based on the intensity of reflected infrared light irradiated from the back of the semiconductor substrate. The back alignment mark is configured by a step formed by the surface of the semiconductor substrate and bottoms of trenches formed from the surface of the semiconductor substrate. A polysilicon film is embedded in the trenches. The back alignment mark has, for example, a cross-shaped planar layout in which three or more trenches are disposed in a direction parallel to the surface of the semiconductor substrate.