Micro bump in semiconductor devices is an element to connect silicon dies with through-silicon vias to be stacked on each other. It is an important technology of 3D integration of semiconductors which allows semiconductors to be more functional in a miniaturized structure. Generally, there are more than 25,000 bumps per a semiconductor die, and the size of micro bumps has been reduced to 10 um. The semiconductors connected by micro bumps are exposed to various mechanical environments by transport, handling and vibration. 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 structure of micro bumps, failure mode and tip speed through finite element analysis and shear test. A shear test was conducted for two micro bump structures with the radius of 25 um using a Dage4000+ bond tester under three tip speeds. The failure mode and force of the micro bump were measured through the shear test. In addition, a finite element model representing the shear test was created by ANSYS and the analysis was conducted under the same conditions as the experiment.This paper shows that the higher the tip speed, the higher the brittle fracture rate. In addition, the change of the vulnerable location was confirmed according to the tip speed condition. The finite element analysis also shows the vulnerable location and stress of micro bump in shear situation.

Evaluation of Mechanical Reliability of Micro Bump in Semiconductors Through a Shear Test

Paper Proceedings: https://asmedigitalcollection.asme.org/ISPS/ISPS2021/volume/84799

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