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. 16, 1993
Filed:
Oct. 08, 1991
Francis S Clube, Neuchatel, CH;
Holtronic Technologies Ltd., Neuchatel, CH;
Abstract
Apparatus for transverse position measurement in a proximity lithographic system including a prism (10) having a glass plate (14) index matched beneath the prism on which a T.I.R. hologram (13) is pre-recorded. A laser source (12) provides a replay beam. A silicon wafer (16) is situated below the hologram and parallel therewith. A second laser source (17) produces through optics (18) a beam with gaussian intensity profile to generate a collimated strip of light (19) at the hologram plane. Elemental grating structures (20) are provided at different locations over the surface of the wafer. Detectors (22,24) collect parts of the lightfield resulting from the interaction of the laser beam with the grating structures. A piezo device (26) operated from a micro-processor (28) moves the silicon wafer in small increments in a direction substantially parallel to the hologram following measurements made by the two detectors which are processed by the micro-processor to produce an alignment signal for the piezo device.