By Topic

Compliant Wafer Level Package for Enhanced Reliability

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$33 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

9 Author(s)
Guilian Gao ; Tessera, Inc, 3099 Orchard Drive, San Jose, CA 95134 ; Bel Haba ; Vage Oganesian ; Ken Honer
more authors

Wafer level package (WLP) volumes are steadily increasing due to their small package size and low manufacturing cost. However, applications to date have been mostly limited to die smaller than 5mm x 5mm. Solder joint fatigue due to stresses generated by the CTE mismatch between the die and the printed circuit board (PCB) limits adoption of WLP for large dies. Tessera's new compliant WLP technology greatly enhances thermal fatigue reliability of the package. A compliant layer under the solder joints effectively dissipates thermomechanical stress between the die and the PCB. FEA analysis was carried out to optimize compliant layer shape and mechanical properties, several materials were evaluated for this application, and prototype units were built. The prototype 9mm x 14mm packages exceeded 1600 cycles of temperature cycling from -40 degC to 125 degC. A compliant WLP package version with copper pins was also developed and tested for continuity at the wafer level. This structure has the potential to reduce wafer level test and burn-in (WLBT) costs substantially by eliminating the need for expensive die contact on the whole wafer contactor.

Published in:

High Density packaging and Microsystem Integration, 2007. HDP '07. International Symposium on

Date of Conference:

26-28 June 2007