Design and Demonstration of 2.5D Glass Interposers as a Superior Alternative to Silicon Interposers for 28 Gbps Signal Transmission

This paper presents the design and demonstration of redistribution layers directly on the surface of glass for high-speed 28 Gbps signaling applications. An unprecedented demand for bandwidth to support cloud and edge computing driven by online services is expected with the continued proliferation of connected devices including smartphones, Internet of Things, and autonomous electric vehicles. High performance systems supporting electrical signal speeds up to and beyond 28 Gbps are required, thus driving the development of advanced multi-chip architectures such as 2.5D interposers. Silicon interposers have been developed and manufactured, but are limited in performance and cost. High conductor and dielectric losses limit maximum data rate, while 300 mm wafer size and expensive damascene processes increase packaging costs. Glass interposers provide similar interconnect densities as silicon but at higher performance and lower cost. The smooth surface roughness (Ra