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:
Apr. 01, 2003
Filed:
Sep. 14, 2000
Hiroki Kikuchi, Kanagawa, JP;
Asahiko Nogami, Tokyo, JP;
Other;
Abstract
For effecting auto-focussing of an objective lens used for observing a semiconductor wafer, a semiconductor microscopic device includes an inspection stage for supporting a semiconductor wafer and an objective lens for observing the semiconductor wafer. For automatic focussing of the objective lens, a defocussing magnitude of a light spot is detected using a knife edge. A collimator lens is oscillated by a voice coil motor to oscillate the light spot on the wafer. A peak value of the defocussing quantity detected at this time is peak-held to generate a position detection signal. The inspection stage is vertically moved so that this position detection signal will be equal to a pre-set target value.