Analysis the interface delamination of Cu and EMC adhesive material in the cutting process of electronic chip based on cohesive zone modeling

摘要

In this paper, cohesive zone modeling (CZM) was adopted to simulate the distribution of temperature & stress field and the interface damage on the Cu/EMC double adhesive material electronic packaging. The following phenomena were found: A sharp rise of the EMC temperature appeared at cut portion field when the cutting began, while it had little effect on copperplate. Stress concentration existed at the cutting surface boundary, and the maximum value occurred at the top of the copper plate which had exceed the yield and tensile strength of the viscoelastic copper, this will be prone to drag and generate burr on the copper surface. Contact surface damage occurred mainly in first time step, the first site of injury occurred in the medial side of the cutting surface. The interfacial tension stress was smaller than the maximum normal stress set up by CZM, while the interface tangential stress was greater than the maximum tangential contact stress that the material can bear, which would cause damage to the bonding interface. Compared with normal strain energy release rate due to separation in normal direction (mode I debonding), shear strain energy release rate due to separation in tangential direction(mode II debonding) was larger, but it did not reach the critical strain energy release rate in the shear directions. The contact interface was not completely cracked and cracking trend was mainly mode II crack in this case.