Ag/Ni Sintering Metallization on Si₃N₄ Ceramic Package Substrate

Metal-coated Si₃N₄ ceramic substrates exhibit exceptional reliability, rendering them highly promising candidates for implementation in high-power electronics. To create Ag/Ni coated Si₃N₄ substrate, Ni coating with a porous structure was generated on the substrate using screen printing in conjunction with a high-temperature sintering technique. Afterward, molten Ag was infiltrated on the surface. The influences of the number of printing layers and the proportion between Ni and organic vehicle on the wettability of Ag were extensively explored by wetting experiments. The wetting results are helpful for the spreading of Ag on the Ni-coated Si₃N₄ substrate. Specifically, the contact angle of Ag on the Ni-coated Si₃N₄ substrate is near to 0° while employing the weight ratio of Ni to the organic vehicle of 2:1 and printing the Ni layer three times. The Ni layers don’t peel off from the Si₃N₄ ceramic surface by the scratch tests. By examining the surface and cross-sectional morphologies and the thickness of the metal layer, the Ag-Ni layer is determined to ~ 160 μm. Moreover, the Ag/Ni coated Si₃N₄ substrate presents a minimum electrical resistivity of 1.26 × 10^-6 Ω/cm while employing the sintering temperature of 1050 °C.