Through Glass Vias Fabrication using Ultrasonic Micromachining and Electroless Deposition

As an alternative substrate for electronics packaging, glass offers numerous potential advantages, including the ability to adjust the thermomechanical and electrical characteristics of the glass to fulfill the requirements of a specific application. Here, the fabrication of through glass vias (TGVs) is presented for using glass as an interposer. A 4 × 4 array of through-holes with an opening of 445 μm × 500 μm was created using abrasive-based ultrasonic micromachining (USM) process, which is a cost-effective, high throughput, and room-temperature process. A thin seed layer of electroless nickel was deposited first, followed by copper electrodeposition to metalize the TGVs. TGVs with an aspect ratio (AR) of ~2.5 were filled conformally, which can be used as 3D interconnects in the packaging of the microsystems.