Factors affecting the reliability of FC-BGA product with multi-stack via
[Introduction] Flip chip ball grid array (FC-BGA) products are widely used in central processing unit (CPU) or graphic processing unit GPU) of computers and servers, so their reliability is very important. [Method] A coupon with through-hole and via (called as R-shift coupon) was designed based on the characteristics of FC-BGA product. The effects of different factors on the reliability of multi-stack via were studied by evaluating the resistance change rate and cross-sectional morphology of R-shift coupon after different cycles of thermal stress test (TST). The failure mechanism of multi-stack via was discussed by combining the thermal stress and strain simulation analysis. [Result] The ABF material, the number of via stack, and the via diameter were the key factors affecting the reliability of FC-BGA products. Both the wall roughness of plated through-hole (PTH) and the microetching amount during lamination pretreatment had little effect on the reliability of FC-BGA products. Different stacks are subjected to different thermal stress and strain during thermal shock, and the bottom of via at the center position of stack was most prone to crack for its greatest thermal stress and strain, leading to the failure of FC-BGA products. [Conclusion] The results of this paper are significant in guiding the design and processing control of FC-BGA products.
万方数据
维普
