1. A manufacturing process method, comprising the steps of: developing a simulation model of a manufacturing process, the simulation model predicting, in dependence upon a plurality of process input parameters, a value for a performance parameter of a product to be manufactured using the manufacturing process; developing a process compact model of the manufacturing process in dependence upon the simulation model, the process compact model calculating a value for the performance parameter in dependence upon the plurality of process input parameters; performing a first process step in the manufacture of the product, the first process step resulting in an intermediate product; after the step of performing, determining a desired value for a particular one of the process input parameters to be used in a second process step in the manufacture of the product, in dependence upon the process compact model, and further in dependence upon a desired value for the product performance parameter, and further in dependence upon a member of the group consisting of an estimated value for a process input parameter used in the development of the intermediate product and an assumed value for a process input parameter to be used in a process step after the first process step; and performing the second process step on the intermediate product in dependence upon the desired value for the particular process input parameter, wherein the step of determining comprises the step of using an optimization algorithm to determine the desired value for the particular process input parameter, in dependence upon the process compact model, the desired value for the product performance parameter, and the member of the group consisting of an estimated value for a process input parameter and an assumed value for a process input parameter.