Solution Overview - Process Control Introduction
Production Process Control begins with measuring the existing process of record (POR) for compliance with performance specifications. The measurement should be as close to actual process conditions as possible, with minimal time offline for testing, and easy to use.
The measurements are tracked versus the process control specifications. When the monitoring metric is within specification, the process passes. When the metric goes out of control limits, the process is down and needs to be diagnosed for root cause and corrective action. SPC charts are commonly used to monitor processes for control.
Fault Detection & Classification:
When the monitoring method determines the process is out of spec, the root cause(s) should be identified prior to any adjustment or corrective action. Root cause analysis requires deep insight into the process conditions and typically much finer detail than monitoring.
If the root cause analysis points to the processing tool settings, the tool will be recalibrated and the process brought back into monitoring control. Calibration should be traceable so the original process is not lost.
Getting the process calibrated recovers from the excursion, but to enhance the performance normally takes a detailed understanding of the sources of error, and the ability to automate fixes to these errors. The metrology system must take the engineer inside the process regime