By Topic

Solder joints reliability with different Cu plating current density in Wafer Level Chip Scale Packaging (WLCSP)

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
$31 $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

4 Author(s)
Cao, K. ; Jiangyin Changdian Adv. Package Co., Jiangyin, China ; Tan, K. ; Lai, C. ; Li Zhang

Electroplated copper is becoming increasingly important in UBM (under bump metallurgy). The Cu is used as a wetting material for the solder (ball). After reflow the Cu and solder joints are the main contact method for mechanical and electrical interconnection to the pads of the chip. One of the critical factors affecting solder joint reliability is the formation of intermetallic compound (IMC); that is generated at the interface of Cu/solder alloy. The formation of IMC is the merging of the plated copper and solder during the reflow process. The IMC will continue to grow when the structure is subjected to temperature. In this study, different current density (0.5ASD, 1.0ASD, 1.5ASD, 2.0 ASD, 2.5ASD, 3.0 ASD) are used on the Cu plating process, which produces different microstructure in the plated Cu layer. It will also impact IMC formation and evolution. The investigation shows that only Cu6Sn5 is generated in as-reflow condition; Cu3Sn is brought forth after being stored at 150 degree C. The early failure was observed at 48 hrs, the fracture is located at the interface of Cu and Cu3Sn in ball shear test. The analysis shows that Kirkendall void formation during aging treatment is the key factor for failure.

Published in:

Electronic Packaging Technology & High Density Packaging, 2009. ICEPT-HDP '09. International Conference on

Date of Conference:

10-13 Aug. 2009