17 May 1994 Wide-field variable NA lens analysis for high-volume 0.5-um manufacturing
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Several techniques were used to evaluate and compare various lenses: optical, SEM, and electrical. In this paper, the emphasis is on `usable' critical dimensions and the effects of the lens on CD control. Lens results were examined at multiple numerical apertures (NAs) and partial coherence settings (PC) using a CD reticle with electrical CD structures over seventeen sites per field. The results were analyzed by electrical methods and a scanning electron microscope (SEM) with CD capability. The influence of external factors was minimized through the use of the same resist/developer batch at all testing locations. We selected electrical and SEM measurement methods for 0.40, 0.45, 0.50 micron structures and compared depth-of-focus, exposure latitude, CD linearity, and isolated vs. dense line/space pairs. Preliminary results show the benefits of electrical testing for increased confidence over the full lens field because of increased sample size. The optical method provided a quick and centered capability and matched electrical results closely. This testing methodology allowed AMD to evaluate lens performance of multiple systems and compare performance equally.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Paul W. Ackmann, Paul W. Ackmann, Stuart E. Brown, Stuart E. Brown, Richard D. Edwards, Richard D. Edwards, } "Wide-field variable NA lens analysis for high-volume 0.5-um manufacturing", Proc. SPIE 2197, Optical/Laser Microlithography VII, (17 May 1994); doi: 10.1117/12.175462; https://doi.org/10.1117/12.175462


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