Semiconductor Fab Equipment Manufacturing worked example

Vacuum Chamber Leak Rate at 99% target first-pass leak-test yield: a worked example

Push target first-pass leak-test yield up to 99% and the picture changes. This example computes every intermediate figure at that operating point. Use it when vacuum chamber leak rate in semiconductor fab equipment manufacturing needs a clean rate and gap-to-target you can put on a tier board.

The inputs for this scenario

  • Chambers failing helium leak test: 8 count (unchanged)
  • Chambers leak-tested this build lot: 250 count (unchanged)
  • Target first-pass leak-test yield: 99 % (raised for this scenario; the documented default is 95)

Working through the calculation

  • Applying the documented formula (Vacuum chamber leak rate = vacuum chamber leak rate count ÷ total vacuum chamber leak rate population × 100) to the inputs above produces each figure below.
  • At this operating point the engine returns 3.2 % for vacuum chamber leak rate, the number this scenario is built around.
  • At this operating point the engine returns 95.8 points for vacuum chamber leak rate gap to target.
  • At this operating point the engine returns 8 count for vacuum chamber leak rate count.
  • At this operating point the engine returns 250 count for total vacuum chamber leak rate population.

How this compares with the baseline

  • Against the tool's baseline example, where target first-pass leak-test yield sits at 95% and the headline result is 3.2 %, this scenario lands almost exactly on the baseline at 3.2 %.
  • It computes what percent of leak-tested chambers failed, and the point gap between that rate and your target first-pass yield. The value of this scenario is the size of the gap it exposes: that gap, priced out over a year, is the budget you can justify spending to close it.

Results at a glance

  • Vacuum chamber leak rate: 3.2 % (headline result)
  • Vacuum chamber leak rate gap to target: 95.8 points
  • Vacuum chamber leak rate count: 8 count
  • Total vacuum chamber leak rate population: 250 count

Run it with your numbers

  • Every input above is editable in the live Vacuum Chamber Leak Rate calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.