TGV filling process based on low temperature conductive silver paste

Through Glass Vias (TGV) interconnection has a wide range of applications in three-dimensional packaging and integrated passive devices due to its excellent electrical properties. The nano conductive silver paste as a common bonding conductive material has good bonding strength with glass and excellent electrical properties, which is a promising alternative to electroplating to fill through-holes with a depth to width ratio of 10:1 or more. In this paper, we demonstrated the feasibility of filling silver paste in 100μm diameter, 400μm deep through-holes and tested the filling effect of the nano-silver paste inside the glass through-hole. Daisy chain and coplanar waveguide structures were fabricated on the glass surface by printing and tested to obtain the I-V curves and S-parameters. The resistivity of the silver paste in the through-hole is 2.56×10^-7 Ω•m and the forward transmission coefficient of the coplanar waveguide with the through-hole structure at 3.3Ghz is -0.11dB, which fits well with the simulated value and proves its good property. Combined with simple process flow and low process cost, paste filling process has great potential for applications in 3D packaging and integrated passive devices.