Browse Prior Art Database

Registration System for X-Ray Lithography

IP.com Disclosure Number: IPCOM000119786D
Original Publication Date: 1991-Feb-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 29K

Publishing Venue

IBM

Related People

Bobroff, N: AUTHOR

Abstract

The proposed alignment system registers the X-ray mask to a fiducial on the wafer stage using the X-ray beam. An optical alignment microscope is then registered to this same fiducial on the wafer stage. The net effect of these two registrations is to precisely locate the optical alignment microscope with respect to the X-ray mask. The chip sites on the wafer are then aligned to the optical alignment microscope.

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Registration System for X-Ray Lithography

      The proposed alignment system registers the X-ray mask to a
fiducial on the wafer stage using the X-ray beam.  An optical
alignment microscope is then registered to this same fiducial on the
wafer stage.  The net effect of these two registrations is to
precisely locate the optical alignment microscope with respect to the
X-ray mask.  The chip sites on the wafer are then aligned to the
optical alignment microscope.

      A fiducial mark on the wafer stage serves a dual purpose as a
detector for X-rays and an optical registration mark for the wafer
viewing microscope.  It consists of a metal on glass film with an
open cross (or other appropriate pattern) in the center.  A
photoemission current is generated by the film when illuminated with
X-rays through an open cross on the mask.  Scanning of the mask or
wafer stage across this fiducial produces a signal which is used to
locate the mask with respect to the fiducial.  The same metal film
fiducial pattern is viewed and registered by the optical alignment
microscope.

      Disclosed anonymously.