How do you calculate wafer sort capacity?

Multiply die tested per cycle by available cycles for gross capacity, then multiply by uptime and first-pass yield. With 4 units/cycle, 480 cycles, 90% uptime and 97% yield you get 4 × 480 × 0.90 × 0.97 = 1,676 good die.

What is the difference between gross and good wafer sort capacity?

Gross capacity is the raw ceiling — 4 × 480 = 1,920 units in the example. Good capacity applies uptime and yield derates to reach 1,676 units, the number you can actually promise as tested-good die.

How much capacity does prober downtime cost?

In the example, 90% uptime removes 1,920 − (1,920 × 0.90) = 192 units before yield is even considered. Downtime is often the single largest recoverable loss in a probe cell.

What is a good prober uptime for wafer sort?

Well-run probe cells target 88-93% availability; above 93% is excellent given probe-card cleaning, needle re-tip, and lot changeovers. The 90% used here is a realistic planning assumption.

Why include first-pass yield in a capacity number?

Because a die that fails probe on first touch either gets retested or scrapped, consuming capacity without producing a shippable good unit. Applying 97% yield to the example trims another 51.84 units from the derated total.

How do I increase good wafer sort capacity?

Add cycles (shifts or probers), lift uptime by cutting probe-card and prober stops, or raise first-pass yield through better contact and cleaning. Uptime gains are usually cheaper than capital, and each point of uptime here is worth roughly 19 good die.

Semiconductor Advanced Packaging & Test calculator

Wafer Sort Capacity Calculator

Wafer sort capacity is the number of good, tested die a probe cell can deliver over a planning period once you discount prober downtime and first-pass yield fallout. Test engineers and capacity planners in back-end operations use it to size probe-card and prober fleets, commit to customer volumes, and decide whether to add shifts or capital. Because wafer sort is the gate that separates known-good die from the rest, its effective throughput directly caps everything downstream in assembly and final test. This calculator separates gross theoretical output from the realized good-die output and quantifies exactly how many units you lose to downtime versus yield.

What this calculator does

Estimate wafer sort capacity for semiconductor advanced packaging and test using production-ready inputs so teams can confirm whether capacity can cover demand before committing the schedule.
Use it when wafer sort capacity in semiconductor advanced packaging and test is being asked to take on more work and you need to know if there is room.
It multiplies probe throughput per cycle by available cycles to get gross capacity, then derates by uptime and first-pass yield to get good tested die.

Formula used

Gross wafer sort capacity = wafer sort capacity output per cycle × available wafer sort capacity cycles
Good wafer sort capacity = gross capacity × expected wafer sort capacity uptime × expected wafer sort capacity first-pass yield

Inputs explained

Wafer sort dies tested per prober cycle:
Available wafer sort prober cycles:
Expected wafer sort prober uptime:
Expected wafer sort first-pass yield:

How to use the result

Use it for probe-cell capacity planning, load balancing across probers, and quoting achievable good-die volumes to fab planning.
It assumes a single steady throughput and yield rate; it does not model index-time variation, retest loops, wafer-to-wafer yield spread, or probe-card touchdown limits.

Current U.S. benchmarks

The producer price index for copper and brass mill shapes stands at 559.593 (BLS, May 2026), up 76.8% from a year earlier. Quotes priced off last quarter's material cost miss this move. Global copper trades at $13,484 per tonne (IMF via FRED, May 2026).
The producer price index for plastic resins and materials stands at 319.371 (BLS, May 2026), up 19.5% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The producer price index for paperboard and containers stands at 276.831 (BLS, May 2026), up 8.8% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The U.S. has 11,261 computer and electronic products establishments employing about 815,443 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate wafer sort capacity? Multiply die tested per cycle by available cycles for gross capacity, then multiply by uptime and first-pass yield. With 4 units/cycle, 480 cycles, 90% uptime and 97% yield you get 4 × 480 × 0.90 × 0.97 = 1,676 good die.
What is the difference between gross and good wafer sort capacity? Gross capacity is the raw ceiling — 4 × 480 = 1,920 units in the example. Good capacity applies uptime and yield derates to reach 1,676 units, the number you can actually promise as tested-good die.
How much capacity does prober downtime cost? In the example, 90% uptime removes 1,920 − (1,920 × 0.90) = 192 units before yield is even considered. Downtime is often the single largest recoverable loss in a probe cell.
What is a good prober uptime for wafer sort? Well-run probe cells target 88-93% availability; above 93% is excellent given probe-card cleaning, needle re-tip, and lot changeovers. The 90% used here is a realistic planning assumption.
Why include first-pass yield in a capacity number? Because a die that fails probe on first touch either gets retested or scrapped, consuming capacity without producing a shippable good unit. Applying 97% yield to the example trims another 51.84 units from the derated total.

Last reviewed 2026-05-12.