Interposer
The silicon or organic layer carrying dense wiring between logic and memory in a 2.5D package.
Current numbers
~$2,400–7,200HBM on one 8–12-stack package at reported stack prices, before die, interposer or substrate
3.5× → 5.5× (2026) → 9.5× (dev)TSMC package roadmap: distinguish interposer reticle multiple from 100 × 100 mm substrate footprint