A method for controlling a processing apparatus used in a semiconductor manufacturing process to form a structure on a substrate, the method including: obtaining a relationship between a geometric parameter of the structure and a performance characteristic of a device including the structure; and determining a process setting for the processing apparatus associated with a location on the substrate, wherein the process setting is at least partially based on an expected value of the geometric parameter of the structure when using the processing setting, a desired performance characteristic of the device and an expected physical yield margin or defect yield margin associated with the location on the substrate.