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High Speed Translation and Rotation of Parts in an E-Beam Tester

IP.com Disclosure Number: IPCOM000043013D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Rogers, WR: AUTHOR

Abstract

To test a part in an E-beam tester it is necessary to align to the part to a predetermined alignment position in order to vector the beam accurately to a test point. The E-beam can search for alignment marks on the part by scanning "zones" on the part where the alignment marks should appear. When alignment marks are found, the data may be sent to a host computer which would perform an algorithm to alter the vector test data accounting for translation and rotation of the part. This method would charge the part unevenly and would produce inaccuracies in beam positioning during testing in the vicinity of the previously charged "zones" unless a discharge cycle was done after alignment. This additional time would slow throughput.

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High Speed Translation and Rotation of Parts in an E-Beam Tester

To test a part in an E-beam tester it is necessary to align to the part to a predetermined alignment position in order to vector the beam accurately to a test point. The E-beam can search for alignment marks on the part by scanning "zones" on the part where the alignment marks should appear. When alignment marks are found, the data may be sent to a host computer which would perform an algorithm to alter the vector test data accounting for translation and rotation of the part. This method would charge the part unevenly and would produce inaccuracies in beam positioning during testing in the vicinity of the previously charged "zones" unless a discharge cycle was done after alignment. This additional time would slow throughput. The alignment method proposed is: Raster scan the total part one time (one frame) with the E-beam at a low accelerating potential. Store the frame in memory. The part will now be in a known, homogeneously charged state in preparation for testing. A software (or hardware) algorithm can be performed on the memory "image" of the part by searching "zones" in the memory for the alignment marks in a manner similar to that which the E-beam itself would have used in the method presently proposed for use (the aforementioned method). All methods of aligning parts in an E-beam tester assume that electron lens distortions are factored out previous to alignment.

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