Development of a laser-assisted bonding process for a flip-chip die with backside metallization

Abstract

Laser-assisted bonding (LAB) is the next generation flip-chip bonding technology that can overcome the limitations of the mass reflow process. The heating mechanism of the LAB process is based on the absorption of the laser's energy by a target material. Previous research reported the reflectance (R), transmittance (T), and absorbance (A) spectra of a silicon sample, which are crucial data for determining the laser parameter, such as power and emission time. The present study reports the equivalent data for a silicon sample with a backside metallization layer. The test vehicle was successfully bonded by optimizing the laser parameter, in special the laser power. The results reported on this research confirms the feasibility of the LAB process for a flip-chip die with backside metallization.