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:
Jul. 04, 1989
Filed:
May. 31, 1988
Murlidhar V Kulkarni, Tucson, AZ (US);
William H Lancaster, Jr, Tucson, AZ (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
The invention is a method for detecting both surface topography and defect presence using an AC interferometer. Surface topography measurements are maximized by adjusting the signal voltage of the light modulator to a relative phase-sensitive value. Defect detection is maximized by adjusting the signal voltage of the light modulator to a relatively phase-insensitive value. This method not only allows for heretofore unknown defect detection by an AC interferometer but, because the signal voltage can be switched electronically, permits both observations to be taken at a high speed and for many points of a specimen, thereby making the method suitable for the manufacturing environment. More specifically, the method would be applicable to both optical disk and microchip manufacturing.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile