SMTA International Conference Proceedings


Voiding Behavior In Mixed Solder Alloy System

Authors: Yan Liu, Ph.D., Derrick Herron, Joanna Keck, and Ning-Cheng Lee, Ph.D.
Company: Indium Corporation
Date Published: 10/14/2012   Conference: SMTA International


Abstract: The voiding behavior of mixed solder alloy systems during BGA assembly was investigated with the use of nitrogen reflow atmosphere. The solder joints were comprised of a combination of Sn62Pb36Ag2 (Sn62), Sn63Pb37 (Sn63), Sn98.5Ag1Cu0.5 (SAC105), and Sn96.5Ag3Cu0.5 (SAC305) as the solder ball or solder paste, except for SnPb solder balls with lead-free pastes. Assembly of each BGA employed a high temperature (HT) profile for lead-free and mixed systems, and a low temperature (LT) profile for mixed and SnPb systems. Mixed systems had higher voiding than lead-free systems when reflowed at HT. SnPb systems had a wider voiding range when compared with mixed systems reflowed at LT. Voiding was found to decrease with reduced alloy surface tension, earlier melting of the bottom solder paste, the top ball remaining solid during reflow, a narrower pasty range, smaller joint overheating, and using flux alone instead of solder paste.

Key Words: 

Voiding, void, solder, solder ball, solder paste, BGA, mixed, lead-free, Pb-free, SnPb, soldering, reflow, solder joint



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