The Surface Treated Nano-silver Particles Assisted Silver Paste for Power Semiconductor Application

The surface treatment technology was applied to study the sintering process of the nano-silver particles (Ag NPs) based paste with an assisted pressure of 0.4 MPa for higher power semiconductor application. In our past work, lauric acid was used as a stabilizer to synthesize Ag nanoparticles with a size of 30-40 nm. The stabilizer of pristine Ag NPs have a lower sintering temperature of 126
^o
C, but the 4.29% of the stabilizers affected the performance of the paste. In contrast, the stabilizer of treated Ag NPs has a 1.98% content and a lower melting point of 120.6
^o
C for the stabilizer. Using pressureless sintering at 175
^o
C, a treated nano-silver paste film has a conductivity of 85.9 μΩꞏcm compared to 970 μΩꞏcm pristine paste. As well, with assisted sintering time of 60 min, pristine joints do not exhibit any shear strength at 175
^o
C. Interestingly, the shear strength of treated Ag NPs paste is increasing to 20 MPa and 35 MPa at 150
^o
C and 175
^o
C, respectively. As the sintering temperature increases to 225
^o
C, the shear strength of 81 MPa is 291.6% greater than the pristine paste(29.8 MPa). As a result of the superior performance, the lower residual should enable the diffusion of silver with gold atoms to form a dense combination layer. These results indicate that the Ag NPs with a low residual can perform excellently in power devices.