By Topic

Evaluation of tin-whisker growth during thermal-cycle testing using stress- and mass-diffusion analysis

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

7 Author(s)
Terasaki, T. ; Mech. Eng. Res. Lab., Hitachi Ltd., Hitachinaka ; Iwasaki, T. ; Okura, Y. ; Suzuki, T.
more authors

To evaluate tin-whisker growth during thermal cycling tests, a simulation technique for calculating the change in atomic-density distribution of tin caused by a change in temperature, which induces a stress gradient in polycrystalline tin plating, was developed. This technique uses the finite-element method (FEM), molecular-dynamics (MD) simulation, and X-ray diffraction (XRD). Specifically, an FEM model was used to simulate stress-induced diffusion, including grain-boundary diffusion, in a tin coating on copper leads by using the stress- and mass-diffusion-analysis function of commercial FEM software. The stress analysis model considered elasticity anisotropy, thermal-expansion anisotropy, and crystal orientation of beta-tin. Crystal orientations were assigned to tin grains in the model according to reference XRD measurements. Diffusion coefficients for the mass-diffusion analysis were calculated by MD simulation. Two models with different crystal-orientation distributions were evaluated. Samples with a higher tin atomic density were found to be more likely to have longer tin whiskers and higher whisker density. It is concluded from these results that the tin-atomic-density distribution calculated with this model can be used as an effective indicator of the propensity to form tin whiskers.

Published in:

Electronic Components and Technology Conference, 2009. ECTC 2009. 59th

Date of Conference:

26-29 May 2009