Method of process stability

A process control architecture comprising an advanced process control (APC) loop, the APC loop comprising:

• a process modeler configured to model process deviation from a process baseline value of a manufacturing process result controlled by a manipulated parameter, and to derive a post-module inspection value based on a manipulated parameter value of the manipulated parameter;
• a filter configured to:
• receive the post-module inspection value derived from the manipulated parameter value;
• receive the manipulated parameter value;
• derive a process target value from the manipulated parameter value, the process target value being a desired outcome of a manufacturing process;
• and
• produce a target delta value from a comparison of the post-module inspection value to the process target value;
• and
• a controller configured to determine the manipulated parameter value from a first input comprising a pre-module inspection value or a second input comprising the target delta value received from the filter;
• wherein a first switch is configured to divert the post-module inspection value from the filter to an equipment performance optimization (EPO) loop configured to restore an equipment parameter to a tool baseline value if the post-module inspection value falls outside an APC tuning range of the APC loop, wherein the EPO loop comprises a kernel configured to receive the post-module inspection value from the first switch and to automatically determine a restoration value to the equipment parameter which restores the tool baseline value, wherein the kernel is independent of the process modeler.