| 摘要 |
Correction of CD variation is accomplished with a second exposure, e.g. using a second reticle. Embodiments include exposing a first wafer with a first dose using a first reflective reticle having a pattern corresponding to a wafer target pattern, or measuring and/or inspecting first reticle pattern portions and calculating and/or simulating corresponding first wafer pattern portions obtained with a predetermined first dosage, identifying CD variations between the exposed wafer or the calculated/simulated first wafer pattern and the target pattern for different target pattern features, exposing a second wafer with the first reticle using a second dose, and correcting the CD variations by applying an additional exposure of the second wafer, before or after exposing the second wafer with the first reticle. Embodiments further include using additional exposures to prevent printing unwanted structures on the reticle or to deliberately vary sizes of selected structures on the wafer for development purposes.
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