By Topic

Predicted size of the inelastic zone in a ball-grid-array (BGA) assembly

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

4 Author(s)
Ephraim Suhir ; University of California, 1158 High St., Santa Cruz, 95064, USA ; Laurent Bechou ; Bruno Levrier ; Damien Calvez

Simple and easy-to-use analytical (mathematical) predictive model has been developed for the assessment of the size of an inelastic zone, if any, in a ball-grid-array (BGA) assembly. The solder material is considered linearly elastic at the strain level below the yield point and ideally plastic above this level. The numerical example carried out for a 30mm long surface-mount package with a 200 micrometer thick lead-free solder has indicated that, in the case of a high expansion PCB substrate, about 7.5% of the interface's length experiences inelastic strains, while no such strains occur in the case of a low expansion ceramic substrate. The FEA computations confirmed this result. The suggested model can be used to check if a zone of inelastic strains exists indeed in the design of interest, and if inelastic strains can be avoided by using a low expansion board or by some other means (say, by using different bonding material at the assembly ends). If not, the model can be used to determine the size of the inelastic zone. It is advisable that such an assessment is carried out prior to the application of a Coffin-Manson-type of an equation (such as, e.g., Anand's model employed in the ANSYS software) aimed at the evaluation of the BGA material lifetime.

Published in:

Aerospace Conference, 2013 IEEE

Date of Conference:

2-9 March 2013