A new fabrication process of TGV substrate with silicon vertical feedthroughs using double sided glass in silicon reflow process

This paper presents a new fabrication process of through glass via (TGV) substrate, which combines glass and silicon into a single wafer. By using double sided glass in silicon reflow process with a patterned silicon mold, a thick and robust TGV substrate which is difficult or timewasting to realize by single side glass reflow process could be achieved. The fabrication process and parameters are studied in details. Surfacing roughness of the TGV substrate after polishing is measured to be 3.421 nm, showing a high surface quality for anodic bonding process. Resistance of vertical feedthroughs are measured in the range of 180 to 260 Ω, indicating that the substrate can be used in a large variety of application. Finally, strength tests of the bonding interface are measured to be as high as 7.28 MPa, indicating a mechanically strong bonding.