EVALUATION of MECHANICAL RELIABILITY of MICRO BUMP in SEMICONDUCTORS through A SHEAR TEST

Abstract

Micro bump in semiconductor devices is an element to connect silicon dies with through-silicon via to be stacked on each other. The failure of these micro bumps is directly related to the reliability of semiconductors. Of the various mechanical tests, a shear test is commonly used to evaluate mechanical reliability because it provides relatively simple and reliable evaluation data. This paper investigated the failure modes of micro bump due to the structure of micro bumps and tip speed through finite element analysis and shear test. A shear test was conducted for four structures of micro bumps with the radius of 25 m using a Dage4000+ bond tester under two tip speeds. A finite element model representing the shear test was developed by ANSYS and the analysis was conducted under the same conditions as the experiment. It shows that tungsten via are effective in increasing shear strength of micro bump. Moreover, it also proposes a robust design to increase shear strength of a micro bump.