SMTA International Conference Proceedings


THE EFFECTS OF CURE PROFILE UPON THE PROPERTIES AND THERMO-MECHANICAL RELIABILITY OF FLIP CHIP UNDERFILL

Authors: Guoyun Tian, Chang Lin, Jeffrey C. Suhling, Pradee
Company: Auburn University (CAVE), Auburn University (LEAP)
Date Published: 9/24/2006   Conference: SMTA International


Seika Machinery, Inc.

Abstract: In this work, the effects of underfill cure temperature and JEDEC MSL preconditioning on underfill mechanical and strength properties, as well as flip chip assembly reliability have been explored. Baseline stress-strain curves, mechanical properties, and interfacial shear strengths of a capillary underfill were recorded for curing at 150 °C and 165 °C (30 minutes). In addition, the changes in the mechanical and strength properties resulting from MSL3 and MSL2 preconditioning were evaluated. The MSL preconditioning of the underfill samples included the JEDEC specified humidity and temperature exposures, plus three simulated reflows at 245 °C or 260 °C. Thermal cycling life tests from -55 to 125 °C were also conducted on daisy chain flip chip assemblies incorporating the same underfill. The test matrix for the reliability testing included both 150 °C and 165 °C curing profiles, and two levels of precondition (none and MSL3). Finally, the failure mechanisms in the flip chip assemblies were studied using CSAM, x-ray and SEM analyses. The results clearly indicate the advantages of the higher curing temperature including improved mechanical properties, superior thermal cycling fatigue life, and enhanced resistance to detrimental effects from moisture exposure and solder reflow.

Key words: Flip chip, underfill, curing, stress-strain curve, preconditioning, and reliability



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