Pattern recognition alignment system

  • US 5,621,813 A
  • Filed: 11/14/1995
  • Issued: 04/15/1997
  • Est. Priority Date: 01/14/1993
  • Status: Expired due to Fees
First Claim
Patent Images

1. An exposure and alignment system comprising:

  • an optical projection system disposed to expose a substrate with an exposure pattern from a reticle;

    an optical alignment system disposed to form a first alignment image of a first region of said reticle defining a first key pattern therein and a superimposed image of a first portion of said substrate defining a first target pattern therein through said optical projection system;

    a memory;

    a pattern recognition system to recognize said first key and target patterns in said first alignment image, wherein said first key and target patterns to be recognized are arbitrary and user selectable, wherein said first key and target patterns are learned by said pattern recognition system and stored in said memory;

    a computational subsystem coupled to said pattern recognition system to compute positions of said first key and target patterns and their positional difference to determine a deviation in position between said substrate and a reference position, in response to said position of said first key pattern.

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