Small via diameter TGV with adhesion layer

Abstract

A through-glass via (TGV) structure and method of forming the TGV structure are described. The TGV structure includes a glass substrate with multiple vias, an adhesion layer of titanium and copper on the via sidewalls, a copper seed layer on the adhesion layer, and copper filling the vias. Fabricate of the TGVs involves depositing the adhesion layer by physical vapor deposition, treating the substrate in an acid solution to enrich hydroxyl groups, functionalizing the substrate with a silane solution, forming a copper seed layer by electroless deposition, and filling the vias with copper. The process may include annealing the substrate before chemical mechanical polishing (CMP) to achieve a smooth surface. The filled TGVs formed have a diameter of less than

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