An investigation of diffusion barrier characteristics of electroless Co(W,P) layer to lead-free SnBi older

Hung Chun Pan, Tsung-Eong Hsien*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

This study investigates the interfacial reactions between eutectic SnBi solder and electroless Co(W,P) layer with various crystallinities via the liquid-state aging (250°C, up to 1 hr) and solid-state aging (120°C, up to 1000 hrs) so as to explore the diffusion barrier characteristics of electroless Co(W,P) to SnBi. In the samples containing SnBi/amorphous Co(W,P) subjected to liquid-state aging, a polycrystalline P-rich layer containing mixed IMC phases formed in between solder and Co (W,P) whereas the lath-like CoSn3 intermetallic compound (IMC) spalled into the solder after 1-hr aging. In the samples containing SnBi/polycrystalline Co(W,P) subjected to liquid-state aging, lath-like CoSn3 IMCs formed with spallation and an amorphous W-rich layer was found in between IMCs and Co(W,P). As to the samples subjected to solid-state aging, reactions of solder and Co(W,P) generated a thick, lath-like IMC layer in between solder and Co(W,P) regardless of the crystallinity of Co(W,P). Analytical results illustrated that the electroless Co(W,P) layer is in essential a sacrificial-type barrier to SnBi solder.

Original languageEnglish
Title of host publicationInternational Conference and Exhibition on Device Packaging 2009
Pages2564-2586
Number of pages23
StatePublished - 1 Dec 2008
EventInternational Conference and Exhibition on Device Packaging 2009 - Scottsdale/Fountain Hills, AZ, United States
Duration: 9 Mar 200912 Mar 2009

Publication series

NameInternational Conference and Exhibition on Device Packaging 2009
Volume5

Conference

ConferenceInternational Conference and Exhibition on Device Packaging 2009
CountryUnited States
CityScottsdale/Fountain Hills, AZ
Period9/03/0912/03/09

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