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:
Feb. 27, 1979
Filed:
Jun. 30, 1977
Michael Hatzakis, Ossining, NY (US);
Constantino Lapadula, Mahopac, NY (US);
Burn J Lin, Katonah, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
In the process of developing exposed photoresist on a substrate, the endpoint in developing away all of the exposed positive photoresist or any other positive resist is detected by exposing a wafer with a predetermined pattern including an optical grating or other special pattern formed in the photoresist upon a test area. In a system employing this concept, a beam is diffracted by the optics of the grating only at a first angle until the resist forming the grating is removed by development. Then a sensor is activated when an angle of reflection is unblocked when the grating disappears. The system is then turned off to stop development by the sensor in an automatic system or, by the operator in a manual system. A double exposure technique is employed to produce the grating or other special pattern.