Formation and Metallization Process Study on High Aspect Ratio Through-Glass-Via (TGV) Within Photosensitive Glass

The electromagnetic simulations of through glass via (TGV) and through silicon via (TSV) were performed in this paper. Simulated results show that the insertion losses of TGV and TSV at 20GHz are -0.024dB and -1.62dB respectively, representing a much higher performance of TGV. Based on photosensitive glass, 7:1 high aspect ratio of TGV was obtained by using high speed wet etching method, achieving better array profile, uniformity and less 1μm roughness of TGVs. Filling process was simulated under different current densities. Results show that smaller current density is helpful to achieve uniform filling due to the improvement of crowding effect of current density at the top and bottom of TGVs, the development speed of copper layer is more uniform and slow. A verification filling experiments were carried out under the current density of 1ASD. Results show a high filling quality, copper layer develops uniformly in 120μm TGVs, the seams are small in 70μm TGVs.