Model-Based CD Control Performance

The paper machine example first introduced in Section 10.1.1 reflects open-loop in CD control data. Application of model-based CD control performance calculations is simplified for this case as U = 0 while the results establish an upper limit of improvement expectations from a potential CD control implementation. Following the procedure summarized in the block diagram of Figure 10.24 simulation calculations provide = 0.0644... 

A unique advantage of the model-based CD control performance calculations is the two-dimensional information detail for improvement potential. Figure 10.25 shows the process variability reduction for each measuremen-... 

Accordingly, CD control performance evaluation requires a special method of model-based approach to compute improvement potential based on a realistically achievable target for that particular process. 

---