Two-stage wafer prealignment system for an optical alignment and

Details Two-stage wafer prealignment system for an optical alignment and Two-stage wafer prealignment system for an optical alignment and

1979-10-22

1982-08-24

Wintercorn, Richard A.

Photocopying

Projection printing and copying cameras

Step and repeat

355 77, 355 78, G03B 2742

Patent

active

043458360

ABSTRACT:
In an optical alignment and exposure machine, particularly suited for aligning semiconductive wafers with and exposing them to microelectronic circuit patterns, two stages of mechanical prealignment of the wafers are performed. In the first stage of mechanical prealignment a wafer is received at a prealignment station where the periphery of the wafer engages at least one of three belt-driven rollers in such a manner as to turn the wafer so as to align a flat side edge or alignment flat of the wafer with two of the three rollers. A transfer arm picks up the first-stage prealigned wafer and transfers it to a rotatable alignment and exposure chuck carried by an X-Y addressable work stage. In the second stage of mechanical prealignment two alignment members coupled to the rotatable chuck for rotation therewith index with the alignment flat of the wafer, and additional alignment members also coupled to the rotatable chuck for rotation therewith index either the center of the wafer or a rounded side edge of the wafer to a predetermined position. An optical alignment system permits rotation of the chuck to more precisely align images of alignment marks on the wafer with alignment marks on the mask. Following such precision alignment of the first wafer, the second stage of mechanical prealignment of each succeeding wafer is performed at the final angular position of the chuck during the preceding precision alignment performed with the optical alignment system. Apparatus is coupled to the chuck for selectively moving a wafer supported on the chuck into engagement with a stop to accurately position the plane of an emulsion on the wafer with respect to a focal plane of the optical alignment system.

REFERENCES:
patent: 3709378 (1973-01-01), Segal
patent: 3865254 (1975-02-01), Johannsmeier
patent: 3902615 (1975-09-01), Levy et al.
patent: 3984186 (1976-10-01), Momose et al.
patent: 4140392 (1979-02-01), Lacombat et al.

Affiliated with

Also associated with

Rating

Two-stage wafer prealignment system for an optical alignment and does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Two-stage wafer prealignment system for an optical alignment and, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Two-stage wafer prealignment system for an optical alignment and will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1434988