Method and apparatus for the production of process sensitive lithographic features
AssigneeKLA-Tencor Corporation
InventorsJoseph J. Bendik, Matt Hankinson
Life of this patent
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Abstract
A method for controlling the variation in process parameters using test structures 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.
Claims14
A method for controlling semiconductor lithographic process parameters comprising:
- forming a test structure on a reticle, the test structure having wavefront engineering features to modify the print transfer characteristics of the test structure;
- transferring the test structure to a first wafer using the lithography process to form a wafer test structure;
- and
- measuring at least a portion of the wafer test structure and comparing it to a reference dimension to determine whether at least one lithographic process parameter has changed and to provide an indirect measure of the change in the at least one lithographic process parameter.
Dependencies are inferred from the claim text.