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Browse Prior Art Database

Pattern Preprocessor for Increased Resolution in Optical Inspection Systems

IP.com Disclosure Number: IPCOM000053011D
Original Publication Date: 1981-Aug-01
Included in the Prior Art Database: 2005-Feb-12
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Dreyfus, RW: AUTHOR [+2]

Abstract

In order to improve the resolution of existing optical inspection scanner a finer optical beam (say one half the diameter) may be substituted and then wiggled at a suitably higher speed during the scan to cover the same field within the same time.

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Pattern Preprocessor for Increased Resolution in Optical Inspection Systems

In order to improve the resolution of existing optical inspection scanner a finer optical beam (say one half the diameter) may be substituted and then wiggled at a suitably higher speed during the scan to cover the same field within the same time.

Existing optical direct inspection equipment has a resolution limited by the beam size. New lasers and optical glasses permit a reduction of the beam size by 2X (or more), which results in finer resolution, and the same overall throughput still can be obtained without modifying existing hardware or any data base of patterns coded in terms of the larger resolution.

The idea is to group 2-4 adjacent beam positions together at the finer resolution and to map them into one beam position at the coarser scale. To get the adjacent positions in sequence, the beam must wiggle. Figs. 1.1 and 1.2 illustrate four adjacent beam inspection positions 10, 11, 12 and 13 occupying approximately the same region formerly occupied by a single beam inspection position having a much larger beam diameter.

The mapping chosen (from the presence or absence of material at positions 10, 11, 12 and 13 into the presence or absence of material in the larger region) can be tailored for sensitivity to the prevailing class of defects sought during inspection (e.g., shorts or opens require different mappings).

The light beam may be wiggled, for example, by passing a polarized opti...