Growth of Cu6Sn5 and Cu3Sn Intermetallic compounds on (111)-, (100)- , and randomly-oriented copper films.

Yu Jin Li, Chih Chen*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

Sn whisker has been found since 1940s.[1] The formation mechanism of whiskers was controversial. There were two possible mechanisms. Some scientists thought whisker formation were the result of recrystallization or abnormal grain growth, however others suggested that the atomic migration of Cu caused by compressive stress gradient were the main driving force of whisker formation. In latest study, Han-wen Lin et al. found that the whiskers growth mechanism is highly related with the growth of intermetallic compounds. The results showed that (100)- or (111)-oriented copper can slow down the growth of intermetallic compounds (IMCs) and whiskers growth. This can prove that the driving force of whiskers is compressive stress gradient produced by serious IMCs formation. As mentioned above, the growth of IMCs plays an important role in whisker formation, and copper are widely used as under bump metallization (UBM) so now we are interesting in the research of the growth mechanism of Cu6Sn5 and Cu3Sn IMCs. Our lab can fabricate highly (111)-oriented nano-twinned copper film and after annealing at appropriate temperature we can get (100)-oriented copper with large grain size. These copper films will serve as substrate. After certain duration of aging test, the results showed that the IMCs of copper and tin grew relatively fast along tin grain boundary. Also, we found that the growth of Cu6Sn5 and Cu3Sn was inhibited on (100)- and (111)-oriented copper films, and the grain of IMCs grew large in randomly-oriented copper film. So we suggest grain boundary diffusion of tin dominate IMCs formation in Cu/Sn system. Moreover, the IMC growth rate on (100)-oriented copper films are even slower than (111 )-oriented copper films.

Original languageEnglish
Title of host publication11th International Microsystems, Packaging, Assembly and Circuits Technology Conference, IMPACT 2016 - Proceedings
PublisherIEEE Computer Society
Pages42-44
Number of pages3
ISBN (Electronic)9781509047697
DOIs
StatePublished - 27 Dec 2016
Event11th International Microsystems, Packaging, Assembly and Circuits Technology Conference, IMPACT 2016 - Taipei, Taiwan
Duration: 26 Oct 201628 Oct 2016

Publication series

NameProceedings of Technical Papers - International Microsystems, Packaging, Assembly, and Circuits Technology Conference, IMPACT
ISSN (Print)2150-5934
ISSN (Electronic)2150-5942

Conference

Conference11th International Microsystems, Packaging, Assembly and Circuits Technology Conference, IMPACT 2016
CountryTaiwan
CityTaipei
Period26/10/1628/10/16

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    Li, Y. J., & Chen, C. (2016). Growth of Cu6Sn5 and Cu3Sn Intermetallic compounds on (111)-, (100)- , and randomly-oriented copper films. In 11th International Microsystems, Packaging, Assembly and Circuits Technology Conference, IMPACT 2016 - Proceedings (pp. 42-44). [7800028] (Proceedings of Technical Papers - International Microsystems, Packaging, Assembly, and Circuits Technology Conference, IMPACT). IEEE Computer Society. https://doi.org/10.1109/IMPACT.2016.7800028