Contactless stacked-die testing for pre-bond interposers

A stacked-die product integrates multiple dies on interposers. In this paper, we first discuss the difficulties of traditional testing mechanism for interposers. To improve production yield, a contactless testing mechanism for pre-bond interposers is proposed. Our testing mechanism attempts to detect a defective interposer from the thermal image after heating the interposer. We propose to extract special features from the thermal image and then use a clustering algorithm to determine whether the interposer is defective. Experimental results show that our testing mechanism can efficiently improve the yield from 70.5% to 96.84%.