Picking large thinned dies with high topography on both sides

Abstract

The process of picking large thinned dies, as a crucial step of the pre-assembly part in a 3D integration flow, has been investigated in this paper. Key factors affecting the yield of this process are identified to be the selection of correct collet material, the needle configuration, and ejection height. By combining correct tools and optimized process parameters, large 50 μm thick dies with dimensions up to 31.6×26 mm2 can be successfully picked. Cu and Sn micro-bumps on both sides of the thin dies are well preserved after the picking process.