Glass Interposer Integration of Logic and Memory Chiplets: PPA and Power/Signal Integrity Benefits

Glass interposers have become a compelling option for 2.5-D heterogeneous integration compared to silicon. It allows 3-D stacking configuration between the embedded dies and the conventional flip-chip dies mounted directly on top at low cost. Furthermore, the interconnect pitch and through-glass-via (TGV) diameter in glass are becoming comparable to their counterparts in silicon. In this study, we investigate the power, performance, area (PPA), signal integrity (SI) and power integrity (PI) advantages of 3-D stacking afforded by glass interposers over silicon interposers. Our research employs a chiplet/package co-design approach, progressing from an register-transfer-level description of RISC-V chiplets to final graphic data system (GDS) layouts, utilizing TSMC 28 nm for chiplets and Georgia Tech’s 3-D glass packaging for the interposer. Compared to silicon, glass interposers offer a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.6\times $ </tex-math></inline-formula> reduction in area, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$21\times $ </tex-math></inline-formula> reduction in wire length, a 17.72% reduction in full-chip power consumption, a 64.7% increase in SI and a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10\times $ </tex-math></inline-formula> improvement in PI, with a 35% increase in thermal. Furthermore, we provide a detailed comparative analysis with 3-D Silicon technologies. It not only highlights the competitive advantages of glass interposers, but also provides critical insights into each design’s potential limitations and optimization opportunities.