Design and demonstration of ultra-thin 3D glass-based 5G modules with low-loss interconnects

This paper demonstrates six-metal-layer antenna-to-receiver signal transitions on panel-scale processed ultra-thin glass-based 5G module substrates with 50-Ω transmission lines and micro-via transitions in re-distribution layers. The glass modules consist of low-loss dielectric thin-films laminated on 100-μm glass cores. Modeling, design, fabrication, and characterization of the multilayered signal interconnects were performed at 28-GHz band. The surface planarity and dimensional stability of glass substrates enabled the fabrication of highly-controlled signal traces with tolerances of 2% inside the re-distribution layers on low-loss dielectric build-up thin-films. The fabricated transmission lines showed 0.435 dB loss with 4.19 mm length, while microvias in low-loss dielectric thin-films showed 0.034 dB/microvia. The superiority of glass substrates enable low-loss link budget with high precision from chip to antenna for 5G communications.