# Interposers, silicon bridges, RDL

Part ID: 1.16 · Layer 1 (Compute silicon & packaging)

The silicon interposers, bridges, and redistribution layers that route signals between a compute die, HBM stacks, and the substrate inside an advanced package.

Interposers and bridges are the wiring layer inside an advanced package: a piece of silicon (or a smaller bridge die) that sits between the compute die and HBM stacks above it and the substrate below (2.5D/3D advanced packaging, ABF / high-layer package substrates), routing the dense set of connections a multi-die AI accelerator package needs. Some of this capacity comes from the same foundries doing the most advanced logic manufacturing, and some from separate interposer-focused suppliers, which makes this sub-category's investor exposure partly overlap with, and partly separate from, foundry exposure itself.
The category's importance to investors is proportional to how many discrete dies a given accelerator package combines — more chiplets and more HBM stacks per package means more interposer or bridge area needed per finished accelerator, independent of overall accelerator unit growth. It's a smaller, more technical sub-position than packaging or substrates broadly, but one where a design shift toward more disaggregated, multi-die accelerator architectures would increase demand per chip even if total chip volume held flat.

**AI delta:** More die per package and more instances of 2.5D/3D packaging per accelerator generation both require more interposer or bridge area, independent of overall unit growth.

## Companies

| Company | Role | Confidence | Ownership | Ticker | Note |
|---|---|---|---|---|---|
| Intel | manufacturer | inferred | public | INTC | EMIB |
| Samsung Electronics | manufacturer | inferred | public | 005930.KS |  |
| TSMC | manufacturer | inferred | public | 2330.TW | CoWoS interposers, LSI bridges |
| UMC | manufacturer | inferred | public | 2303.TW | interposer supply |

Confidence tags: disclosed = company/filing statement; reported = trade press or partner list; inferred = taxonomy lead.