Frame opto-mechanical device has the spatial resolution of 5μm and FOV of 6.4 x 5.1 mm. And defect inspection can be completed within 150 ms for the chip size of 2.5 x 3.0 mm. The processes of image acquisition and defect inspection can be accomplished during the chip sorting process to satisfy the real-time online inspection. Inspected chips are placed in GO/NG trays in real-time according to their quality. From the verification results compared with the ones by microscope, the inspection accuracy is better than system requirements. The over kill rate is less than 0.3% and 3% for chip boundary flaws and hole-inside defects respectively. But it still can’t be inspected correctly for the hole-inside defects of only one membrance breakage. In the future, we will improve the illumination and detecting algorithm to solve this imperfection. Inspection systems have been integrated into our customer’s chip sorters, and successfully delivered to and accepted by end-users for online operations. Our system also can be accommodated to other customer’s chip sorters with specific requirements for chip backside inspection.
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Ming-Fu Chen, Chih-Chung Chou, Chun-Chien Lien, Rui-Cian Weng, "Development of an AOI system for chips with a hole on backside based on a frame imager," Proc. SPIE 9903, Seventh International Symposium on Precision Mechanical Measurements, 99031F (26 January 2016);