Link cleanroom assumptions to the reference fab

Use the reference environment sliders to recalculate defect-density, yield and expected good-die estimates.

In Cloud and the Windows app, link the ISO class and downflow assumptions in Design to wafer to the reference fab environment. Begin with a valid design source loaded; the vFactory guide explains the design handoff.

Set the reference environment

  1. Select Reference fab, then open Fab settings → Environment. Use the example reference fab for this connection; imported layout previews keep their environment separate.

  2. Adjust Airborne particle cleanliness (dust) and Downflow air velocity. Their ranges are ISO classes 1–9 and 0–1 m/s.

  3. Select Design to wafer. Under Cleanroom environment · Assumptions, select Use the fab environment sliders for ISO class and downflow. The two sliders replace the independent ISO class and downflow fields.

Cleanroom environment · Assumptions in Design to wafer with Use the fab environment sliders for ISO class and downflow checked: the Airborne particle cleanliness (dust) slider at ISO 14644-1 class 5 (allowed 1 to 9), the Downflow air velocity slider at 0.40 m/s (allowed 0 to 1 m/s), and the Threshold D, Settling speed, Exposure, Deposition fraction and Killer fraction inputs.

With the checkbox selected, the two linked sliders replace the separate ISO class and downflow fields.

Imported, host-supplied and reopened inputs keep their own assumptions until you select this checkbox. Linking adopts the current reference environment. The particle threshold, settling speed, exposure and deposition and killer fractions keep their existing values.

Check the recalculated result

  1. Select Calculate preview to read Geometry and yield estimate, including Cn proxy (particles/m³), Environment D0 (defects/cm²) and the yield probabilities.

  2. After a completed run, move either linked slider. Recalculated for the current environment confirms that yields and expected good dies were recalculated over the same simulated lots.

  3. If Save this result to the project is shown, select it to save the revised result. The recalculation is not saved automatically.

Use independent values

Clear the checkbox to keep the latest values as independent numeric inputs. Earlier imported values are not restored. Editing a numeric input clears the current result; use Calculate preview or Run design to wafer again.

Reference-fab and environment values are illustrative assumptions. The ISO concentration proxy and deposition mapping are uncalibrated estimates, not measured cleanliness, yield or certification.