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:
Nov. 09, 1993
Filed:
Dec. 31, 1991
Henry H Law, Berkeley Heights, NJ (US);
AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
A method is described for monitoring the rate at which metal layers are chemically etched. The method involves an indicator layer of metal formed on a surface of a monitor substrate. The thickness of the indicator layer varies according to a wedge-shaped profile along a longitudinal axis. The indicator layer is exposed to an etchant medium for a predetermined duration. During such exposure, a portion of the indicator layer is completely removed, exposing the underlying surface and creating an edge between the exposed surface and the remaining portion of the indicator layer. The etching rate is determined by reference to the longitudinal location of the edge.