Laser-Assisted Sintering of Silver Nanoparticle Paste for Bonding of Silicon to DBC for High-Temperature Electronics Packaging

This article presents the development of a laser-assisted sintering method of a silver nanoparticle paste for bonding of a silicon chip to a direct bonded copper (DBC) substrate for high-temperature electronics packaging applications. The effects of the bonding parameters such as laser power, bonding pressure, and time on shear strength were studied. For comparison, samples using hotplate bonding were also produced and studied. Shear strength, cross section, and fracture surface analysis were carried out in reliability studies. The results show that shear strength of 10 MPa can be achieved at the bonding pressure of 3 MPa, laser power of 70 W, and a very short irradiation time of 1 min. The shear strength reached 20 MPa when the irradiation time was increased to 5 min. The research indicates that the shear strength can be improved by increasing the bonding pressure, laser power, and hence the sintering temperature and the irradiation time. The laser-assisted method with a short irradiation time of 5 min can produce the same level of shear strength as compared with the hotplate-based approach requiring a sintering time of tens of minutes. With the ability of fast and localized heating effect, the laser-assisted sintering method can improve the manufacturing efficiency for packaging of high-temperature electronics and sensors.