As transistors have shrunk and compute performance has skyrocketed, one stubborn bottleneck has remained: interconnects. Whether on-chip, between dies, or across boards, the physical wiring that moves data often becomes the limiting factor in speed, energy efficiency, and overall system performance. In 2025, researchers and manufacturers are tackling this constraint head-on with a variety of novel interconnect technologies—from optical and wireless links to glass substrates and AI-optimized topologies.
Traditional copper interconnects, while mature and inexpensive, face serious challenges at nanometer scales. As line widths shrink below 10 nm, resistance-capacitance (RC) delays, crosstalk, and power dissipation balloon. Signal integrity becomes difficult to maintain, especially for high-frequency or wide data buses such as those used in AI accelerators or high-performance networking chips. The result is an increasing performance gap between computation and communication—what’s sometimes referred to as the “interconnect tax.”
To reduce this tax, chipmakers are investing in 2.5D and 3D integration with advanced packaging, such as silicon interposers, bridges, and embedded multi-die interconnect bridges (EMIB). These allow high-bandwidth chiplet communication with ultra-short traces and minimized parasitics. AMD and Intel have both shown commercial silicon using these techniques, with bandwidths exceeding 2 TB/s between dies. But even these systems are running into thermal and scaling limitations.
Enter glass interposers—a promising alternative to silicon. Glass offers lower electrical loss, better dimensional stability, and the potential for ultra-fine redistribution layers (RDLs). At SEMICON West 2025, TSMC revealed its progress on glass-based advanced packaging, claiming improved thermal expansion matching and up to 30% better signal integrity for 112 Gbps PAM-4 signals. Industry observers believe glass could become a dominant interposer material by the late 2020s, particularly for AI-centric multi-chiplet designs.
Meanwhile, optical interconnects are gaining traction for both intra-package and board-level communication. Companies like Ayar Labs and Intel are pushing commercial adoption of co-packaged optics (CPO), where lasers and modulators sit directly on or next to the compute die. These systems offer massive bandwidths with much lower energy per bit—down to 1 pJ/bit compared to 10–15 pJ/bit for electrical SerDes. The challenge lies in integrating photonics with CMOS at scale and cost, but progress is accelerating.
Wireless interconnects, while still largely experimental, present intriguing possibilities. Research prototypes using millimeter-wave and THz antennas etched into silicon have shown die-to-die communication with no wires at all—potentially useful for modular systems, in-field reconfiguration, or secure links.
Even at the PCB level, materials innovation is helping interconnects keep pace. Companies are moving toward ultra-low-loss laminates and high-density interconnect (HDI) stackups to support 112 G and 224 G signaling. New AI tools are also emerging to assist with trace optimization, impedance matching, and crosstalk mitigation, allowing more efficient board layouts without manual tuning.
The broader implication is clear: the future of computing won’t be defined solely by the power of individual cores or transistors, but by the efficiency of the highways connecting them. As chiplets, accelerators, and distributed compute systems proliferate, interconnect technology becomes a first-class design concern—one that can no longer be treated as an afterthought.
