Release Time:2019-03-12  Hits:

Indexed by: Journal Article

Date of Publication: 2017-02-27

Journal: APPLIED PHYSICS LETTERS

Included Journals: EI、SCIE

Volume: 110

Issue: 9

ISSN: 0003-6951

Abstract: beta-Sn grain orientation and configuration are becoming crucial factors to dominate the lifetime of solder interconnects in three-dimensional integrated circuit packaging. In this paper, we found that a temperature gradient during solidification significantly dominated the orientation and configuration of the final beta-Sn grains in Cu/SnAgCu/Cu micro interconnects. Being different from the random orientations and growth fronts meeting or cyclic twin boundary forming near the center after homogeneous temperature bonding, the beta-Sn grains solidified under a certain temperature gradient were observed to follow a highly preferred orientation with their c-axis departing from the direction of temperature gradient by about 45 degrees-88 degrees. Meanwhile, these preferred oriented beta-Sn grains consisted of low angle grain boundary structures with misorientation in the range of 0 degrees-15 degrees. The mechanism was explained in terms of the anisotropy and directional growth of beta-Sn grains. The results pave the way for grain orientation control in 3D packaging technology. Published by AIP Publishing.