Characterization of interconnects and RF components on glass interposers

As a result of their myriad of advantages over silicon and other conventional substrate technologies, glass substrates have received significant attention from the electronic packaging and system integration community worldwide. So far, most of the research effort on glass has concentrated on developing methods for fabricating cylindrical through glass vias (TGVs). However, to fully evaluate the potential of glass as an interposer material for microelectronic systems with computing and communication functions, an extensive characterization of interconnects and RF components on these substrates must be carried out. In this contribution, we go beyond state-of-the-art research and present an in-depth characterization of TGVs, coplanar lines and 60 GHz coplanar excited patch antennas on two glass substrates. One of these substrates has a low alkaline content (Borofloat33®) and the other is alkaline-free (AF32®). The effects of these glass materials on the RF performance of TGVs, coplanar lines and 60 GHz antennas are extensively studied, and recommendations for performance optimization are proposed. For experimental verification, test samples are fabricated and measured. Very good correlation is obtained between the measurement and simulation results from 100 MHz to 100 GHz.