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:
Sep. 25, 2018
Filed:
Apr. 01, 2016
Disco Corporation, Tokyo, JP;
DISCO CORPORATION, Tokyo, JP;
Abstract
A wafer is produced from an ingot having an end surface. The method includes an end surface measuring step of measuring undulation present on the end surface, and a separation plane forming step of setting the focal point of a laser beam inside the ingot at a predetermined depth from the end surface, which depth corresponds to the thickness of the wafer to be produced, and next applying the laser beam to the end surface to thereby form a separation plane containing a modified layer and cracks extending from the modified layer. The height of an objective lens for forming the focal point of the laser beam is controlled so that the focal point is set in the same plane to form the separation plane, according to the numerical aperture NA of the lens, the refractive index N of the ingot, and the undulation present on the end surface.