Direct copper metallization on glass technology + x-substrate

It is believed that conformal metallization on glass with the highly conductive thick Cu material is expected to enhance the performance for RF electronic devices in the IoT era due to the outstanding RF properties of the glass and high-Q nature of Cu metallization. Previously, metallization on the glass with sputtering and printing technology is demonstrated. However, there are some concerns in terms of throughput and mechanical integrity of sputter seed layer for Cu metallization on TGV (thru-glass via) sidewalls and the smooth glass surfaces. Here we study our novel metallization technology to obtain good adhesion without degrading the RF performance associated with glass properties and Cu conductivity. Surface cleaning is critical to obtain good adhesion. In this experiment, glass surface was cleaned by the irradiation of UV light and alkaline degreasing with complex agent. UV light and alkaline degreasing make the clean surface of the glass and improved Cu adhesion to glass with minimal stress to the glass itself. We have successfully demonstrated direct cupper plating on TGV holes with filling via and conformal plating for RF front end filters with better performance (Cu - glass adhesion 0.4kN/m).