CoWoS Cost Console
CoWoS — the 2.5D packaging behind every flagship AI GPU — mounts a logic die and several HBM stacks on a large silicon interposer. Estimate the full packaging cost: the interposer (sized from your die and stacks, with yield that falls as it grows), the HBM, assembly and substrate — and compare CoWoS-S, -R and -L. The number that often exceeds the logic die itself.
Logic die, HBM stacks & variant → full CoWoS package cost.
2.5D package console
A large interposer is losing meaningful yield. Each good interposer carries the cost of the scrapped ones — consider CoWoS-R/L or fewer stacks.
HBM (5 stacks) is the biggest line at $1,250 (82%). All variants are feasible at this size.
Model HBM precisely in the HBM Cost console and the logic die in Wafer Cost.
Why CoWoS defines AI hardware cost
TSMC's CoWoS capacity — not logic-wafer capacity — has repeatedly gated how many AI GPUs the world can build. The packaging step, once an afterthought, became the supply chokepoint of the AI boom.
A CoWoS interposer can exceed 3× the reticle limit (~2,600mm²+), making it one of the largest pieces of silicon in the package. Because yield falls with area, a huge interposer can lose enough dies to become a major cost line by itself.
Four to eight stacks of HBM3/HBM3E at hundreds of dollars each can total more than the GPU die they feed. For many accelerators, memory plus packaging — not the compute silicon — is the bulk of the bill of materials.
TSMC introduced RDL-based CoWoS-R (cheaper, higher-yielding) and LSI-based CoWoS-L (scales past 3× reticle) precisely because full-silicon CoWoS-S yield and size limits were constraining the largest AI packages.
The package that became the AI bottleneck
When the world ran short of AI GPUs, the constraint wasn't logic-wafer capacity — it was CoWoS. The 2.5D packaging that bonds a compute die to its high-bandwidth memory turned out to be the scarcest, most specialized step in the whole supply chain, and for a stretch of the AI boom it literally set the ceiling on how many accelerators could ship. That reversal — packaging as the bottleneck — is why understanding CoWoS cost and capacity went from niche to essential.
CoWoS works by placing the logic die and several HBM stacks side by side on a silicon interposer, a large passive chip whose dense, short wiring delivers the bandwidth large models demand. The interposer is the heart of both the technology and its cost: because it must span the logic die plus all the memory stacks, it grows past two and three times a normal reticle, and since yield falls exponentially with area, a big interposer scraps enough units that the survivors carry a heavy cost — exactly the dynamic this console models with a Poisson yield on the interposer area.
But the interposer often isn't even the largest line item — the HBM is. Four to eight stacks of HBM3 or HBM3E, each a 3D-stacked, TSV-connected memory device costing hundreds of dollars, frequently total more than the logic die's entire manufacturing cost. For many accelerators the story of the bill of materials is memory and packaging, not compute silicon.
TSMC's response to the size and yield limits of full-silicon CoWoS-S was to diversify the family: CoWoS-R swaps the silicon interposer for RDL on organic (cheaper, higher-yielding); CoWoS-L uses local silicon interconnect bridges to scale past three reticles. For the memory line, the HBM Cost console goes deeper; the logic die comes from the Wafer Cost console.
Trusted by Packaging Architects & AI Hardware Teams
“The interposer-yield-vs-area modeling is exactly why our largest accelerator moved to CoWoS-L. Showing leadership how interposer cost explodes past 3× reticle on CoWoS-S, with the layout diagram, made the variant decision obvious. Closest browser estimate to our internal model I've seen.”
“Finally a tool that separates interposer, HBM, assembly and substrate. The realization that HBM often exceeds the logic die cost lands hard with the breakdown in front of you. I use the presets to sanity-check H100/B200-class BOM estimates.”
“We model CoWoS capacity and cost together — this captures why packaging, not logic wafers, gated AI GPU supply. The variant comparison (S vs R vs L) is the conversation the whole industry is having. Pairs perfectly with the HBM estimator.”
“Great for first-order accelerator BOM math in negotiations. The interposer yield term is the insight competitors' tools miss. Would love HBM-generation presets, but linking to the HBM estimator covers it.”
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interposer area ≈ (logic + stacks × footprint) × 1.25 · yield = e^(−area × D0) · representative parameters · Last reviewed: 2026-06