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. 03, 1987
Filed:
Mar. 13, 1985
Karl W Edmark, III, Seattle, WA (US);
GCA Corporation, Andover, MA (US);
Abstract
The calibration scheme disclosed herein is applicable to microlithographic systems of the type in which alignment between successive exposures is provided by means of a microscope mounted to one side of the optical projection column, there being a laser metered stage for transporting a semiconductor wafer between the microscope and an optical projection column. In accordance with the practice of the invention, a wafer with a light sensitive coating is placed on the stage and transported to the column using an approximate base line value. After exposure from a reticle which includes fiducial markings, the wafer is transported by the stage to the microscope. By observing the latent image on the coating, the precise stage movement required to align the latent image of the fiducial markings on the wafer with the microscope system reference reticle may be measured with the laser metered stage. The base line value is then corrected based on the actual measurement.