Large-Area Bonding by Sintering of a Resin-Free Nanosilver Paste at Ultralow Temperature of 180 °C

In order to achieve superior interfacial heat dissipation, large-area (≥400 mm²) sintering of a novel nanosilver paste at ultralow temperature (180 °C) was successfully realized using extra terpineol solvents at interfaces by promoting the diffusivity of Ag nanoparticles, i.e., Ag NPs, into device metallization as well as extra diffusion channel. Under auxiliary pressure of ≤ 5 MPa, strong joint can be obtained with a shear strength of > 500 kgf and a steady-state thermal resistance of 0.273 °C/W, close to that of traditional nanosilver joints sintered at >250 °C. Thanks to the increase of diffusion mobility due to the terpineol solvent as well as more fast diffusion channel, much more Ag NPs can be diffused to the chip metallization, improving the adhesive bonds at interfaces greatly for achieving large-area bonding at such low sintering temperature.