SMTA International Conference Proceedings


EFFECT OF BALL SIZE ON UNDERCOOLING OF Sn-Ag-Cu SOLDER JOINTS

Authors: R. Kinyanjui, L. P. Lehman, and E. J. Cotts
Company: Binghamton University
Date Published: 9/25/2005   Conference: SMTA International


Abstract: A differential scanning calorimeter (DSC) was used to carry out systematic measurements of the melting and solidification temperatures of Sn-3.5Ag-1.0Cu (wt.%) Pb-free solder alloys bumped onto electronic packages. The distributions of the undercooling temperatures for stand-alone Sn-3.9Ag- 0.6Cu (wt.%), eutectic Pb-Sn and Sn were also determined.

A dependence of the undercooling temperature on sample size was observed for Sn, Sn-3.9Ag-0.6Cu (wt.%), and eutectic Pb-Sn samples. Corresponding results were observed for the solidification of 88 solder bumps of Sn-3.5Ag-1.0Cu (wt.%) solder alloys reflowed onto Cu/Ni/Al metallization pads. These samples displayed a median undercooling of about 60oC for a cooling rate of 1.0oC/s.

Key words: Size, undercooling, Sn dendrites, microstructure.



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.


Back


SMTA Headquarters
6600 City West Parkway, Suite 300
Eden Prairie, MN 55344 USA

Phone +1 952.920.7682
Fax +1 952.926.1819