Universal Liquid Metal Interconnects for Next‐Generation Glass Packaging

Advances in 2.5D heterogeneous integration demand interconnect technologies that combine fine pitch, thermal and mechanical reliability, and scalable manufacturability on glass interposers. Here, we introduce a versatile platform that exploits the fluidic and electrical properties of gallium‐based liquid metal (LM), leveraging LM's larger skin depth than copper to mitigate high‐frequency skin‐effect losses. First, vacuum‐assisted capillary infiltration forms conformal, void‐free LM‐filled through‐glass vias, eliminating seed‐layer deposition and electroplating while lowering thermal budget. Second, 3D direct microprinting of LM writes interconnects with 5 µm resolution, enabling dense chip‐to‐interposer fan‐out beyond wire‐bonding limits. Third, an LM‐based anisotropic conductive adhesive (LM‐ACA) provides vertical electrical interconnection and mechanical adhesion at room temperature and low pressure, reducing assembly complexity and supporting panel‐scale integration. Integrating these technologies, we demonstrate stable operation, including real‐time sensing, processor operation, and chip‐to‐chip communication, establishing LM as a fine‐pitch, thermally resilient, and scalable interconnect medium for glass‐based 2.5D packaging.