Fab KPI Dashboard
The two numbers that run a fab floor: OEE — availability × performance × quality — and WIP from Little's law. Compute both, benchmark OEE against world-class, and find the weakest component dragging the whole down.
Availability, performance & quality → OEE.
Operations console
OEE is 85% — 0 points below the 85% world-class mark. The weakest component is availability at 90% — improving it lifts OEE the most, since the three rates multiply.
Lifting the weakest to 95% would raise OEE to about 89%.
At 500/day and a 60-day cycle, 30,000 wafers are in process. Cutting cycle time at fixed throughput cuts WIP and lead time one-for-one.
A 85% OEE means 15% of the equipment's potential output is lost to downtime, slow cycles and defects combined. Focus on availability.
Quality losses tie to scrap — price them in the Wafer Scrap console.
Why OEE and WIP run the floor
Overall Equipment Effectiveness = Availability × Performance × Quality. Because they multiply, 90% on each is only 73% OEE — every component has to be strong for the whole to be.
Across industries, ~85% OEE (roughly 90% availability × 95% performance × 99.9% quality) is considered world class. Most operations run well below it, leaving large recoverable capacity on the table.
Work-in-progress = throughput × cycle time. It's an identity, not an estimate — so cutting cycle time at fixed throughput directly cuts WIP, freeing capital and shortening lead times.
Because OEE multiplies, the lowest of the three components limits the whole — improving the weakest one lifts OEE most. Chasing an already-high component yields little.
Two identities that govern a fab
Run any factory and two relationships govern almost everything. The first is OEE — Overall Equipment Effectiveness — the product of availability, performance and quality. The second is Little's law — work-in-progress equals throughput times cycle time. Neither is an estimate; both are exact, and together they connect how well equipment runs to how fast and how much it produces.
OEE's power is in its multiplication. Of the planned time, only the available fraction runs; of that, only the performance fraction is at full speed; of that, only the quality fraction is good. Each stage passes a fraction of the last, so they compound — which is why ninety percent on each is only seventy-three percent overall, and why a single weak component drags the whole down. The practical corollary is decisive: improve the lowest of the three, because chasing one that's already near its ceiling buys almost nothing. This dashboard flags that weakest rate for you.
Little's law is deceptively simple and endlessly useful. Because work-in-progress is throughput times cycle time, the three are locked together — fix any two and the third follows. Its most valuable rearrangement is that, at a fixed throughput, cutting work-in-progress cuts cycle time one-for-one. That's the mathematical heart of lean manufacturing: less inventory in the line means shorter lead times, faster yield learning, and less capital tied up — all from the same identity.
For a semiconductor fab, these play out per tool and per step. The bottleneck tools' OEE caps fab capacity, so a point of OEE on a lithography scanner is worth a great deal, and cycle time drives both customer lead time and how fast the fab learns. Quality losses here are the same dies the Wafer Scrap console prices, and the yield behind quality comes from the Yield Predictor.
Trusted by Fab Operations & Industrial Engineering Teams
“OEE as the product of three rates with the weakest one flagged is exactly how I run an improvement review — it points the team at availability when that's the drag, not the already-high quality. Little's law WIP from throughput and cycle time ties capacity and inventory together. Clean and exact.”
“The 90%×90%×90%=73% lesson is the one that lands hardest with new supervisors. Benchmarking against 85% world-class sets the target instantly. The WIP-cycle-time link drives our lean program. Pairs well with the wafer-scrap and yield tools.”
“Per-tool OEE with the weakest component is how we prioritize the bottleneck scanners. Little's law for WIP is the identity our scheduling rests on. Would love multi-tool roll-up, but for a tool/line dashboard it's spot on.”
“Fast, exact OEE and WIP with sane presets. The weakest-rate guidance focuses the daily standup. The world-class band keeps targets honest. Exactly the operational dashboard the floor needs.”
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OEE = availability × performance × quality · WIP = throughput × cycle time (Little's law) · world-class OEE ≈ 85% · Last reviewed: 2026-06