Numerical Control System for Semiconductor Manufacturing
Original Publication Date: 1985-Oct-01
Included in the Prior Art Database: 2005-Feb-19
A closed-loop system is described for numerical correction, to a manufacturing specification, of lithographic cameras and other semiconductor process tools which are subject to classifiable errors that are correctable through tool adjustments. Lithographic cameras have fixed, built-in errors that are essentially irreducible and temporal errors which can be monitored and adjusted for. These latter errors, taken over a population of the semiconductor product, give rise to variability in the product. This variability exceeds the inherent uncertainty of the lithographic or measuring tools. However, on an individual wafer basis, these errors are machine-correctable.