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AI supply chain term

Interposer

An interposer is a thin base layer of silicon that sits under multiple chips and provides the dense, high-speed wiring that links them together.

What it means

An interposer is an intermediate layer, most often made of silicon, placed between chips and their package substrate to route thousands of fine, high-speed connections between neighbouring dies. In a 2.5D design, a GPU or accelerator die and its stacks of high-bandwidth memory sit side by side on the interposer, which carries the wide, short data paths they need to move information quickly. This is the physical foundation of packaging platforms such as CoWoS. The interposer belongs to the advanced-packaging layer of the AI supply chain, downstream of wafer fabrication but essential to assembling a modern accelerator. Because silicon interposers are large and themselves consume advanced fab and packaging capacity, they are one of the concrete constraints behind reported packaging shortages for AI chips.

Why it matters to investors

Large silicon interposers consume scarce advanced-packaging capacity, so the firms that supply the platform and its tools capture value as AI accelerators scale. TSMC's CoWoS platform is built around the interposer, while BE Semiconductor, Disco, and Onto Innovation provide the bonding, dicing, and inspection steps it requires.

See Interposer in the AI value chainIts live model score, why it matters, and every company exposed to it.

Companies on this part of the chain

TSMCTSMBE Semiconductor Industries N.V.BESIDisco Corporation6146.TOnto InnovationONTO

Named to show where the term sits in the AI supply chain — research, not advice, and never a recommendation to buy or sell.

Related terms

CoWoS (Chip-on-Wafer-on-Substrate)Chip-on-Wafer-on-Substrate — the advanced packaging that fuses compute dies and memory into one accelerator.Advanced packagingAssembling compute dies and memory into a finished, working chip — a real capacity bottleneck.HBM (High-Bandwidth Memory)High-Bandwidth Memory — DRAM stacked next to an accelerator to feed it data fast; often the real limit on GPU output.ChipletA chiplet is a small, specialized silicon die that is combined with other dies in one package instead of building a single large monolithic chip.

See Interposer in the live AI chain.

THE ENTITY maps every constraint onto one live model — which part is tight now, who owns it, and who gets squeezed when it moves. Plain-English reads you can check.

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THE ENTITY is an educational read on the AI supply chain — research, not investment advice. It explains how the chain works and who sits where, never price targets or buy/sell calls.