Knob is fab and process-engineering slang for a controllable recipe parameter, whether or not the tool has a physical dial for it. Engineers talk about which knobs move CD, turning the time knob, or a run-to-run controller owning the dose knob. In experiment planning the knobs are the candidate factors, and a good process has a few strong knobs with predictable, independent effects.
Pressure is the only knob that moves uniformity without hurting rate. Put it in the DOE at three levels.
Also heard as
- process knob
- tuning knob
- control knob
Related terms
Factor
Input variable deliberately set at chosen levels in an experiment, such as temperature, pressure, time or supplier.
DOE
Design of experiments: planning a set of runs that vary several factors at once so their effects can be separated.
Chasing the mean
Shop phrase for adjusting a process after each reading to pull it back to target, which only adds variation.
Sweet spot
Region of factor settings where every response meets its target at once, found by overlaying response contour plots.