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. 03, 1987
Filed:
Jun. 19, 1986
Edward H Phillips, Middletown, CA (US);
Compact Spindle Bearing Corporation, Middletown, CA (US);
Abstract
A dark field alignment system is provided wherein a bifurcated light source, including a secondary channel having spot sources of light located in a plane conjugate to the object plane of a reduction lens and directed through a peripheral ring of a plane conjugate to the apertgure plane of the reduction lens, illuminates the object plane of the reduction lens. Reflected and defracted light from an alignment mark of a semiconductive wafer in the image plane of the reduction lens is captured by a mirror located near the aperture plane of the reduction lens. This light is refocused to another plane conjugate to the object plane of the reduction lens and imaged onto detector arrays to provide alignment information. Also provided is an alignment mark system wherein the relative positions of alignment windows in an array of alignment windows, and alignment patterns in a corresponding array of alignment patterns are selected such that an image of an edge of each reticle alignment window illuminates a first edge of a counterpart alignment mark without illuminating any other edges of the alignment marks when the marks and windows are properly aligned.