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AI supply chain term

CoWoS (Chip-on-Wafer-on-Substrate)

Chip-on-Wafer-on-Substrate — the advanced packaging that fuses compute dies and memory into one accelerator.

What it means

CoWoS is the advanced packaging technology that fuses a logic compute die and its stacks of HBM memory onto a single shared base, so they behave as one accelerator. Modern AI chips are no longer one piece of silicon — they are several pieces stitched together, and that stitching is what CoWoS does. The process is delicate, capacity is concentrated at a small number of facilities, and it takes time and capital to expand. As a result, packaging — not the printing of the chip itself — is often the true ceiling on how many AI accelerators can be delivered in a given quarter.

Why it matters to investors

Advanced packaging capacity is a quieter chokepoint than the chips it joins, but it can be the binding one. When CoWoS is tight, accelerator shipments are gated upstream of the foundry, the packaging leader gains leverage, and equipment suppliers that help expand packaging lines benefit. It is a textbook case of the bottleneck sitting one layer below where the headlines look.

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

Companies on this part of the chain

TSMCTSMNVIDIANVDAApplied MaterialsAMAT

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

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.FoundryA factory that manufactures chips designed by others; leading-edge capacity is scarce.YieldThe share of chips on a wafer that work; low yield means fewer usable parts.

See CoWoS 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.