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Indexed by:Journal Papers

Date of Publication:2020-06-01

Journal:MATERIALS TODAY COMMUNICATIONS

Included Journals:EI、SCIE

Volume:23

ISSN No.:2352-4928

Key Words:3D packaging; Single crystal; Prism-type; Temperature gradient; Intermetallic alloys and compounds; Electronic materials

Abstract:The morphology evolution of Cu6Sn5 grains in (001)Cu/Sn/Cu and (011)Cu/Sn/Cu micro solder joints reflowing with and without a temperature gradient was studied. In the as-soldered state, regular and perpendicular prism-type Cu6Sn5 grains formed on (001)Cu substrate, while a mixture of stubby prism-type and scallop-type Cu6Sn5 grains formed on (011)Cu substrate. The prism-type morphology gradually transferred into scallop-type after isothermally reflowed at 270 degrees C for 10 min. However, with a temperature gradient, the initial perpendicular small prismatic Cu6Sn5 grains on (001)Cu substrate and mixed-type Cu6Sn5 grains on (011)Cu continued to grow into large prism-type. All the prism-type Cu6Sn5 grains grew along same direction after long time reflow under temperature gradient due to the merging of adjacent Cu6Sn5 grain pair.