Thermal and Electrical Study of Glass Interposers in Co-Packaged Electronic–Photonic Systems

This article investigates the use of glass interposers as a scalable and cost-effective solution for co-packaged electronic–photonic systems, with a focus on optimizing thermal management and electrical transmission. The thermal management study is carried out through design, assembly, and characterization of a thermal test vehicle. The thermal test vehicle is used to study the heat dissipation in glass interposers by varying the through glass via (TGV) pitch ( 100-400 μm). The outcomes indicate a maximum surface temperature rise of 2.9 °C, which is also confirmed by finite element method simulations. Moreover, the simulations also suggest that changes in TGV pitch below 100 μm do not significantly impact the temperature variation. The electrical transmission through the glass interposer package is investigated using three different design scenarios (transmission lines on glass, glass interposer, and electrical test vehicle). The RF performance of each design is studied up to 40 GHz to analyze the losses incurred by different components in the package. In conclusion, this work presents an optimized electrical design for the test vehicle. By employing strategically designed geometries for TGVs, microvias, and ball grid array (BGA) pads, we achieved a significant reduction in insertion loss of approximately 11 dB at 40 GHz. This design approach can be compatible with 2.5-D and 3-D integration schemes, enabling high-density and high-performance electronic–photonic packages.