Influence of cooling temperature on temporary bonding of heterogeneous wafers
摘要
Fan-out wafer-level packaging (FO-WLP) is emerging as a key technology in advanced semiconductor packaging due to its advantages in miniaturization, high performance, and system integration capabilities. As a critical step in the FO-WLP process chain, temporary bonding presents significant thermal management challenges that directly affect packaging yield and reliability. This paper focuses on the temporary bonding process between epoxy molding compound (EMC) and glass wafers, and systematically investigates the influence of cooling rate on thermal stress evolution and bonding quality in heterogeneous material systems. By establishing an accurate finite element model for thermal stress adaptation in heterogeneous wafers and validating it through bonding experiments, the effects of cooling rate on interfacial temperature gradients, thermal stress distribution, and structural deformation are revealed in-depth. Results indicate that when the upper and lower heating plates are cooled at the same rate, a cooling rate of 3 K min−1 is optimal, which effectively suppresses thermal mismatch stress, reduces the cracking risk, and balances process efficiency. This investigation can provide key theoretical support for controlling thermal stress and process optimization at heterogeneous bonding interfaces.