Low Temperature Sintering of Silver Nanoparticle Paste for Electronic Packaging

Silver nano paste as die attach materials could achieve low temperature joining and high temperature application in the microelectronics industry. Large scale synthesis the silver nanoparticles is still critical issue. This study demonstrated that silver nanoparticles were cost-effectively and environmental-friendly synthesized by arc discharge in liquid. Silver nanoparticles were spherical and well dispersion, and had three distributions and the average sizes are 6 nm, 40 nm and 220 nm, respectively. This mixed size silver nanoparticles and certain content polymer form silver nano paste, which used as die attach materials to sinter the chip and Al2O3 direct bonded copper (DBC) substrate. The results showed that the shear strength of die attachment joint could reach 18 MPa. There were two fracture types of joint during die shear: interfacial and partial interfacial fracture. Increasing the sintering temperature could improving the shear strength of die attachment joint.