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Cartesian Translation-Polar Rotation of a Memory Image to Align a Part in an E-Beam Substrate Tester

IP.com Disclosure Number: IPCOM000043015D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Rogers, WR: AUTHOR

Abstract

A test part for an E-Beam tester must be properly aligned. This can be done by: 1. The test part is raster scanned, stored in memory, and the cartesian coordinate location of two alignment marks and the distance between them are factored in. 2. The design alignment vectors have the electron lens distortion values factored in from a previous calibration routine. 3. The translation alignment tolerance excludes the possibility of more than one part image feature being within the translation tolerance "window" (Fig. 1). Memory (not the part) can be searched for the x, y location of the image translate alignment mark (Fig. 2). The vector difference between the design and image translate align mark will become a constant operator which will translate each vector of data during test.

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Cartesian Translation-Polar Rotation of a Memory Image to Align a Part in an E-Beam Substrate Tester

A test part for an E-Beam tester must be properly aligned. This can be done by:
1. The test part is raster scanned, stored in memory, and the cartesian coordinate location of two alignment marks and the distance between them are factored in. 2. The design alignment vectors have the electron lens distortion values factored in from a previous calibration routine. 3. The translation alignment tolerance excludes the possibility of more than one part image feature being within the translation tolerance "window" (Fig. 1). Memory (not the part) can be searched for the x, y location of the image translate alignment mark (Fig.
2). The vector difference between the design and image translate align mark will become a constant operator which will translate each vector of data during test. Assume that the rotation alignment mark was in the opposite corner of the part from the translation alignment mark (not required). The length of the design and image polar from the translation to the rotation mark will be the same. The polar origin (x,y,) was found in part 1. Memory will be searched (by algorithm) by inspecting those addresses which lie on the locus of points prescribed by the arc of the polar, until the image rotate align mark is found. The polar angle theta can then be found by utilizing the known polar length and calculating the vector length from the now known design and...