By Topic

Effects of underfill material properties on the reliability of solder bumped flip chip on board with imperfect underfill encapsulants

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)
Lau, J.H. ; Express Packaging Syst. Inc., Palo Alto, CA, USA ; Lee, S.W.R. ; Chang, C. ; Ouyang, C.

The effects of underfill material properties on the reliability of solder bumped flip chip on printed circuit board (PCB) with imperfect underfill encapsulants were studied. Three different types of underfill imperfections were considered; i.e., (1) interfacial delamination between the underfill encapsulant and the solder mask on the PCB (crack initiated at the tip of underfill fillet); (2) interfacial delamination between the chip and the underfill encapsulant (crack initiated at the chip corner); and (3) the same as (2) but without the underfill fillet. Five different combinations of coefficient of thermal expansion (CTE) and Young's modulus with the aforementioned delaminations were investigated. A fracture mechanics approach was employed for computational analysis. The strain energy release rate at the crack tip and the maximum accumulated equivalent plastic strain in the solder bumps of all cases were evaluated as indices of reliability. Besides, mechanical shear tests were performed to characterize the shear strength at the underfill-solder mask interface and the underfill-chip passivation interface. The main objective of the present study is to achieve a better understanding of the thermo-mechanical behavior of flip chip on board (FCOB) assemblies with imperfect underfill encapsulants

Published in:

Electronic Components and Technology Conference, 1999. 1999 Proceedings. 49th

Date of Conference:

1999