Paper Title:

Micro Impact Testing of Lead Free Solder Joints

Periodical Advanced Materials Research (Volume 32)
Main Theme Frontiers in Materials Science and Technology
Edited by John Bell, Cheng Yan, Lin Ye and Liangchi Zhang
Pages 99-102
DOI 10.4028/
Citation Ranjan Rajoo et al., 2008, Advanced Materials Research, 32, 99
Online since February 2008
Authors Ranjan Rajoo, Erich H. Kisi, D.J. O'Connor
Keywords Drop Impact Reliability, High Strain Rate, Lead-Free, Micro Impact Testing, Solder, Solder Interconnections, Solder Joint
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This paper presents data obtained from a newly-developed instrument to test the quality of solder interconnections at high strain rate – the ‘micro-impactor’. This shear test of the interconnection at high strain rate mimics the stress experienced by the solder joint when undergoing shock due to drop-impact. Instrumented with a load cell and linear variable displacement transducer (LVDT), it also has the ability to provide dynamic impact force and displacement data. Earlier concepts to characterise the solder joint at high strain rates such as the miniature pendulum impact tester [1] lacked this capability. This micro-impactor was used to study the effect of increasing silver (Ag) and copper (Cu) concentration in solder alloys on the shear strength of the solder joint. The performance of these lead-free alloys was also compared to that of the well-established leaded solder. It was found that increasing the silver content increases the yield strength of the solder, causing the failure to occur at the brittle intermetallic layer instead of in the bulk of the solder.