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:
Mar. 03, 1987
Filed:
May. 17, 1985
William T Batchelder, Menlo Park, CA (US);
John A Piatt, Soquel, CA (US);
Kenneth M Sautter, Sunnyvale, CA (US);
GCA Corporation, Andover, MA (US);
Abstract
In the resist development method disclosed herein, the spin development of a resist coating on the surface of a semiconductor wafer is monitored by measuring light scattered back from the wafer surface from an incandescent source. During development, the sensed light level oscillates due to optical fringing caused by the thinning of the resist layer in the exposed areas and the fringe generated oscillation essentially stops when the development breaks through in the exposed areas. By comparing sample data obtained from the sensed light level with template data representing a known or characteristic behavior, a control point corresonding to the last fringe may be determined. Development is then terminated a calculated time after the control point.