抄録
A spatial filtering is applied to the inspection of TAB (Tape Automated Bonding) leads for faster image processing in comparison with conventional visual inspection systems. TAB leads with various size of pseudo-defects are fabricated by lithographies. Two types of filters, directly photographed and theoretically designed, are manufactured for the evaluation of filtering performance. A defect detection sensitivity - a ratio of filtered defect intensity to background noise, is defined to compare the performance numerically. A sensitivy greater than 20 is obtained for various types of 8×8-micrometer defects, which corresponds to 1/5 of a lead width of 40 micrometer and sufficient for actual use. The robustness of the filtering is also examined for the both positioning errors of the filter and the TAB leads. A maximum tolerance of 0.15mm for the filter displacement and that of 5mm for the TAB leads are obtained for sensitivities of more than 20.
