A Highly Compatible and Step-by-step Temporary Bonding and Debonding Strategy for Ultra-thin Wafer Level Package

With the increasing demands for lightweight, low- power, multifunctional and high-performance electronic device, such as power devices, intelligent sensors, memories and quantum devices, it has become increasingly difficult to manufacture high-performance chips solely by reducing process dimensions to meet the future development needs of integrated semiconductor devices. Over the past decades, wafer level package has been demonstrated to overcome the limitations of Moore’s Law in the physical expansion of chip manufacturing processes through three-dimension vertical interconnection technology and thin wafer processing. Temporary bonding and debonding, as a novel wafer level package technology, can provide necessary mechanical support for large-scale wafer’s three-dimension stacking and back thinning. In this paper, we proposed a highly compatible and step-by-step temporary bonding and debonding strategy. The wafer was bonded to the carrier via polymer adhesive through thermal compression bonding. The front of wafer was debonded by thermal sliding, and the back was debonded by ultraviolet laser irradiation. This strategy offers a wide process window which can be compatible with wafer process conditions such as back thinning, ion implantation, metal deposition, laser annealing and flip chip interconnection. The packaged device using this step-by-step temporary bonding and debonding technology shows an average yield of over 90%.