A.R.E.A. - Effect Of PCB Surface Finish on Sn Grain Morphology and Thermal Fatigue Performance of Lead- Free Solder JointsAuthors: Babak Arfaei, Ph.D., Martin Anselm, Ph.D., Francis Mutuku, Eric Cotts, Ph.D.
Company: Universal Instruments Corporation and Binghamton University
Date Published: 9/28/2014 Conference: SMTA International
In this work, different PCB surface finishes such as Cu-OSP, ENIG, ENEPIG, and HASL (commonly used in the microelectronic industry) and some recently developed surface finishes such as ENTEK-OM and Pallaguard were evaluated. The effects of varying surface finish on the microstructure of SAC305 lead-free LGAs and BGAs were investigated. Sn grain morphology was characterized by crossed polarizer light microscopy (PLM). The effect of variation in solder volume and surface finish on Sn grain morphology and lifetime was assessed.
A clear correlation between PCB surface finish, microstructure and reliability was observed. LGA samples assembled on HASL surface finish showed the highest degree of interlaced joints; those samples outperformed joints reflowed on other surface finishes. LGA samples showed more interlaced Sn grain morphology than larger BGA samples. Use of Pallaguard surface finish resulted in very poor performance of both BGA and LGA components in ATC tests.
Sn Grain Morphology, ATC, PCB Surface Finish, LGA, Thermal Fatigue, Pb-free
Members download articles for free:
Not a member yet?
What else do you get when you join SMTA? Read about all of the benefits that go along with membership.
Notice: Sharing of articles is restricted to just your immediate work group. Downloaded papers should not be stored on an external network or shared on the internet.