METHOD AND APPARATUS FOR THE PRODUCTION OF PROCESS SENSITIVE LITHOGRAPHIC FEATURES

摘要

A method for controlling the variation in process parameters using test structures (102, 104, 106, 108, 100) sensitized to process parameter changes. Wavefront engineering techniques are used to make features of the test structure more sensitive to process changes. Focus and exposure parameters are adjusted in response to the measurements of the test structures. In another embodiment, the wavefront engineering features are placed to permit the test structure appearing on the reticle out of focus. The wavefront engineering feature is an OPC technique applied to the test structure to modify it. The OPC features are applied in an asymmetrical manner to the test structure and enable identifying the direction of process focus changes.