Copper wire reliability and bonding integrity robustness on cratering sensitive bond pad structure

Abstract

With the continue soaring of world's gold price semiconductor companies are force to re-channel their effort to copper wire capability and reliability development as packaging interconnect material to replace gold wire. Besides, cost saving copper wire has many advantages over gold in term of mechanical and good electrical together with improve thermal conductance. Its also offer stable electrical resistance after thermal aging with lower and stable intermetallic growth on top of lower diffusion rate. These advantages have lead to lower heat generation and improved bonding thermal reliability integration compare to its gold wire predecessor. Cratering and oxidation are the two main challenges copper wire faced due to the nature of copper materials properties itself. The 5N & 4N copper wire sparking power and time influence towards ball bond grain size distribution and bonding stress correlation to cratering sensitve bond pad structure couple with optimum bond parameter were studied in addition to FEA Cu ball stress and strain distribution modeling. Mechanical, thermal and moisture reliability stress test like TC 1OOOX, HTS @175 Deg C, HTRB, H3TRB, PCT ( 96 hrs tests were performed on top of pad etching, ball shear adU wire pull destructive test were assess to validate the robustness of copper wire bonding integrity.