SMTA International Conference Proceedings


IMPACT OF UNDERFILL AND SOLDER JOINT ALLOY SELECTION ON FLIP CHIP SOLDER JOINT RELIABILITY

Authors: Dave Hillman and Ross Wilcoxon
Company: Rockwell Collins, Inc.
Date Published: 9/26/2004   Conference: SMTA International


Abstract: Thermal cycle testing of underfilled flip chip devices mounted to a BT circuit board was performed to characterize their reliability. Daisy chained components with either eutectic (Sn63) or lead free, i.e., Pb-free, solder joints were evaluated with one of three underfill materials (Loctite® 3568, Loctite® 3593, and Hysol® FP4527). A total of 2104 thermal cycles from -55°C to +125°C (approximately one hour per cycle with 15 minute dwells at each extreme temperature) were performed and the components were monitored to identify when solder joint failures occurred. Testing revealed that the Pb-free solder joints failed much earlier than those with eutectic solder.

Components with Hysol® FP4527 were only slightly less reliable than those with Loctite® 3568. The results indicate that the Pb-free solder evaluated in this study would not be suitable for Rockwell Collins applications, using present materials and process parameters. On the other hand, this flip chip device with eutectic solder joints and the reworkable Loctite® 3568 underfill completed more than 1000 thermal cycles without failure and therefore is considered to be suitable, per Rockwell Collins standards, for ground-based military and commercial avionics systems.

Key Words: Flip Chip, reliability, thermal cycle testing, underfill, lead 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.


Back


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

Phone +1 952.920.7682
Fax +1 952.926.1819