No abstract

No abstract

No abstract

Miniaturized 3D package with shorter distances between chips are needed for the mobile and high frequency applications. Chip-to-chip stacking for 3D packaging using conventional assembly method and single step reflow attachment is the most cost-effective. But fine pitch microjoints of stacked chip by single re-flow attachment is challenging due to chip movement during stacking processes, which lead to poor assembly yields. This paper reports a method of stacking chips by thermal tacking and permanent joints are formed simultaneously by single re-flow step.