Effect of Moisture Conditioning on EMC/Copper Interfacial Fracture Energy and the Cohesive Zone Parameters
Research Report Highlight
Modified CZ Parameters were obtained to model the strength of the experimentally humidity- and temperature-conditioned EMC/Copper interfaces present in flip chip packages, 3-D IC packages, SOIC packages and multichip modules.
This report provides modified cohesive zone parameters through experiments and simulations for EMC/copper interface that is subjected to moisture conditioning and compares these modified cohesive zone parameters against the cohesive zone parameters for pristine CMC/copper interface. In particular, 1. The critical SERR (Gc) of EMC/Copper pristine interface is first determined by conducting interfacial fracture experiments. These experiments include double cantilever beam test and four-point bend test. 2. From the load versus displacement experimental data of the interfacial fracture experiments, Gc can be calculated through FEM and analytical calculations. The variation of Gc as a function of mode mixity is then determined. 3. Using load vs. displacement experimental data as well as Gc variation as a function of mode mixity, the cohesive zone parameters are then determined for as-received or pristine EMC/copper interface. 4. EMC/Copper specimens are then subjected to different humidity conditioning, and the interfacial fracture mechanics experiments are then repeated at room temperature. 5. As discussed in Step #2 and #3, modified CZ parameters are then determined for humidity-conditioned EMC/Copper samples. 6. The modified CZ parameters for conditioned samples are compared against the CZ parameters for as-received pristine samples, and a discussion is provided as to effect of humidity conditioning on CZ parameters.