Systems and methods that improve process control in semiconductor manufacturing are disclosed. According to an aspect of the invention, conditions in a cluster tool environment and/or a wafer therein can be monitored in-situ via, for example, a scatterometry system, to determine whether parameters associated with wafer production are within control limits. A cluster tool environment can include, for example, a lithography track, a stepper, a plasma etcher, a cleaning tool, a chemical bath, etc. If an out-of-control condition is detected, either associated with a tool in the cluster tool environment or with the wafer itself, compensatory measures can be taken to correct the out-of-control condition. The invention can further employ feedback/feed-forward loop(s) to facilitate compensatory action in order to improve process control.