Feasibility Investigation of Amorphous Silicon as Release Layer in Temporary Bonding for 3-D Integration and FOWLP Scheme

Abstract

A reliable temporary bonding scheme with both inorganic amorphous silicon release layer and HD-3007 polyimide based on high 355-nm-wavelength laser absorption coefficient in release layer is proposed and investigated. Effects of laser absorption coefficient and laser ablation path are also studied to develop a high throughput laser ablation process. The bonding scheme can be achieved within the optimized temperature of 210 degrees C under 1 MPa bonding force. In addition, chemical resistance, mechanical strength with reliability assessment, and thermal stability test for bonded structure are inspected. There is no obvious degradation in electrical characterization after laser ablation, indicating that the temporary bonding scheme has high potential to be used for 3-D integration applications.