Abstract
We investigated the effect of material combinations of adhesive film (NCF) and build-up substrates on non-metallurgical interconnection reliability in several test element group (TEG) samples. The initial electrical conductivity results in each TEG sample confirmed the validity of the assumed failure mechanism at high temperatures. In this situation, the interconnection reliability deteriorates when the material combination causes a large plastic strain in the gold bump during temperature cycling. The low temperature failure mechanism was also clarified. At low temperatures, a bimetallic warpage due to a thermal mismatch during the cooling process reduces the compressive contact stress in the gold bumps at the corners of the chip. From these failure mechanisms, we found that thinning the silicon chip is an effective means of enhancing interconnection reliability at both high and low temperatures.
