Challenges of Adhesion Promotion for the Metallization of Glass Interposers

Ultra-miniaturization and 3D integration of electronic systems require interposers with a very high density of off-chip interconnections. Silicon and glass interposers are being developed widely to meet these needs. Through hole via formation or Through Package Via (TPV) in combination with the ability to handle of thin glass materials have already been demonstrated in combination with “polymer on glass” technologies at Georgia Tech Packaging Research Center and by industrial partners. However there is an increasing industry demand to plate electroless copper directly onto smooth glass substrates which is extremely challenging. This is being driven by the desire to be able to benefit from the ability to utilize existing infrastructure and therefore fully benefit from the cost advantages wet-chemical metallization can offer in the manufacturing of glass interposers. It is therefore worthwhile to investigate replacing adhesion promoting techniques such as sputtered metal seed layers or laminated polymer fil...