1. A method for processing wafers in a fab, said method comprising the steps of: (1) receiving, at a first functional unit, one or more functional unit property targets associated with said first functional unit; (2) generating one or more tool targets for one or more tool level functional units, by processing said one or more functional unit property targets associated with said first functional unit; (3) forwarding said one or more tool targets to said one or more tool level functional units; and (4) generating one or more tool recipes defining one or more process setpoints, by processing said one or more tool targets at said one or more tool level functional units.