Characterization and Mechanism of Sintered-silver Die-attach on Electroless Nickel Surface Finish with Different Phosphorus Content

The low temperature silver (Ag) sintering technology has attracted a lot of attention as die-attach for power electronics modules packaging. The most reported studies involved sintered-Ag bonding on Ag or gold (Au) surface finish. Compared to Ag or Au, electroless nickel (phosphorus) or Ni(P) is a cost-effective and widely-used process for surface-finishing module substrates. However, research on sintered-Ag bonding on the Ni(P) surface is limited. In this study, IGBT devices were attached using pressureless Ag-sintering on electroless Ni(P)-plated substrates with different P content. Mechanical, electrical, and thermal properties were characterized via die-shear strength, static output characteristics, and thermal resistance, respectively. TEM and EDS were then conducted to investigate the bonding mechanism between sintered-Ag on Ni(P). The findings in this study helps to understand the effect of P content and promote the application of sintered-Ag die-attach on Ni(P) surface finish for power module packaging.