Thermal-Mechanical Process Simulation of an Advanced NCF Technology

The paper introduces an advanced nonconductive film (NCF) typed FC technology employing a novel compliant composite interconnect structure. The interconnect reliability and bondability of the technology are demonstrated through experimental thermal humidity (TH) test in conjunction with a two-point daisy chain resistance measurement. The alternative goal of the study aims to look into the insight of the thermal-mechanical behaviors of the novel packaging technology during NCF bonding process and thermal testing through numerical modeling and experimental validation. For effectively simulating the bonding process, a process-dependent finite-element (FE) simulation methodology is performed. The validity of the proposed methodology is verified through several experimental methods, including a Twyman-Green (T/G) interferometry technique for warpage measurement, and a four-point probe method for contact resistance measurement. At last, a design guideline for improved process-induced thermal-mechanical behaviors is presented through parametric FE analysis. Both numerical and experimental results demonstrate the feasibility in applying the novel compliant interconnects to achieve a proper contact stress at various temperature environments so as to hold a low and stable connection resistance at elevated temperature. Most importantly, the novel interconnects survive the 85degC/85%RH TH test for 500 hours.