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. 21, 1995
Filed:
Dec. 17, 1993
Steven G Barbee, Dover Plains, NY (US);
Tony F Heinz, Chappaqua, NY (US);
Ulrich Hofer, Munich, DE;
Leping Li, Poughkeepsie, NY (US);
Victor J Silvestri, Hopewell Junction, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method and apparatus for detecting an etching endpoint of a film on a substrate whereby a first excitation beam of light having a prescribed wavelength is provided, the first light beam substantially containing only a first harmonic component of light at that wavelength. The first light beam is directed at a prescribed incident angle to an interface between the film and the substrate, the first light beam being reflected off the interface to thereby provide a second light beam, the second light beam containing the first harmonic component of the first light beam and a generated second harmonic component. The generated second harmonic component is detected and a first output signal representative thereof is provided. A generated second harmonic component reference of the first light beam is produced and a second output signal representative of a generated second harmonic component reference is provided. The detected second harmonic component of the first light beam is normalized, as a function of the first and second output signals, in real-time, and a third output signal representative of an occurrence of a prescribed change in the normalized detected second harmonic component is provided. The prescribed change corresponds to the etching endpoint of the film on the substrate.