17 May 1994 Analyzing deep-UV lens aberrations using aerial image and latent image metrologies
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The technique of direct aerial image metrology (AIM) has been applied to characterize the performance of a microlithographic lens. AIM is potentially faster and more reproducible than measurements obtained by scanning electron microscopy. Direct measurement of the aerial image eliminates both the process variations associated with resist processing as well as the subjective nature of evaluating resist profiles. We have used AIM to evaluate some of the primary aberrations of a 248 nm stepper lens. We compare the results to those obtained with latent image scatterometry, a proven technique for measuring lens performance. We found that AIM, while providing qualitatively good results, contained some slight systematic errors that reduced the accuracy of the data. The sources of error and their remedies are discussed.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Eric L. Raab, Christophe Pierrat, Charles H. Fields, Robert L. Kostelak, William G. Oldham, Sheila Vaidya, "Analyzing deep-UV lens aberrations using aerial image and latent image metrologies", Proc. SPIE 2197, Optical/Laser Microlithography VII, (17 May 1994); doi: 10.1117/12.175450; https://doi.org/10.1117/12.175450


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