Effect of compression pressure on strength of low-temperature sinter bonding produced using silver formate

Novel pressure-assisted sinter bonding at 200°C using silver (Ag) formate particles was performed in air using an Ag-finished die and substrate to achieve a reliable Ag bondline even at high temperatures. The Ag formate particles, prepared by immersing Ag₂O particles for 3 min in a formic acid solution, indicated a pyrolysis reaction near 130°C, forming pure Ag and gases (carbon dioxide and hydrogen). With a paste prepared by mixing the Ag formate particles with α-terpineol, the bonding under 10 MPa exhibited an adequate shear strength of 270 MPa after 3 min. Moreover, a near-full-density structure was observed in the formed bondline after 10 min. Consequently, the compression pressure of 10 MPa resulted in significantly enhanced bondability with reduced void fraction in the formed Ag bondline.