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. 04, 1989
Filed:
May. 06, 1986
Mark Davidson, Palo Alto, CA (US);
KLA Instruments Corporation, Santa Clara, CA (US);
Abstract
A specially adapted Linnik microscope is used in combination with a video camera, a wafer transport stage and data processing electronics to form a novel inspection apparatus based on the use of the two beam interference microscope. The apparatus can utilize either broad band or narrow band light to develop a plurality of interference images taken at different axial positions relative to the surface under investigation. The point-by-point brightness along scan lines across such images is then used to develop data which is proportional to the degree of coherence (or to the fringe amplitude, the variance of the fringes, or the amplitude of oscillation of the fringes) as the optical path difference is varied in a two beam optical or acoustic microscope.