Thermo-mechanical Reliability Analysis of Copper TSV

Abstract

TSV technology raises several reliability concerns particularly caused by thermally induced stress. In traditional package, the thermo-mechanical failure mostly occurs as a result of the damage in the solder joint. In TSV technology, however, the driving failure may be TSV interconnects. In this study, the thermomechanical reliability of TSV technology is investigated using finite element method. Thermal stress and thermal fatigue phenomenon caused by repetitive temperature cycling are analyzed, and possible failure locations are discussed. In particular, the effects of via size, via pitch and bonding pad on thermo-mechanical reliability are investigated. The plastic strain generally increases with via size increases. Therefore, expected thermal fatigue life also increase as the via size decreases. However, the small via shows the higher von Mises stress. This means that smaller vias are not always safe despite their longer life expectancy. Therefore careful design consideration of via size and pitch is required for reliability improvement. Also the bonding pad design is important for enhancing the reliability of TSV structure.

Various Cu Filling Methods of TSV for Three Dimensional Packaging

“…TSV를 충전하는 전도성 금속으로는 Cu가 대표적으 로 사용된다 [4][5][6][7][8][9] . TSV에 Cu를 충전하는 전류인가 방법으로 직류전류 (direct current, DC) 15) , 펄스 전류(pulse current, PC) 16) , 펄스-역펄스 전류(pulse reverse current, PRC) 17) , 주기적인 펄스-역펄스 전류(periodic pulse reverse current, PPR) 18,19) 참 고 문 헌…”