Patent ID: 7566181

Claim:
A method of controlling the critical dimensions of structures formed on a wafer, comprising: a) developing photoresist on top of a film layer on a wafer using a developer tool, the photoresist development being a function of developer tool process variables including temperature and length of time of development, wherein the wafer is heated by a hot plate in the developer, the hot plate having zones with each zone having a separate temperature setting; b) after a), performing one or more etching steps on the film layer on the wafer using an etch tool; c) after b), obtaining diffraction signals of structures at a plurality of locations on the wafer using an optical metrology tool; d) after c), generating a profile of critical dimension measurements of the structures across the wafer using the diffraction signals obtained in c); and e) adjusting the separate temperature settings of two or more of the zones of the hot plate based on the generated profile of critical dimension measures of the structures across the wafer.