26 July 1999 Intrawafer CD control in state-of-the-art lithography
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In this work, die-to-die CD-variations across a wafer are investigated as a potential important contribution to the global gate CD-control. Measuring the non-uniformity in different experiments using CD-SEM and ELM revealed different parameters, impacting the measured non-uniformity value. It will be pointed out that the measurement itself can have a significant contribution to the measured 3(sigma) -value, especially using CD-SEM, if the level in non-uniformity is low. Further on, it will be shown that the choice of resist and developer chemistry can have a high impact on the i-W CD non-uniformity. Moreover, the potential impact of exposure and track processing will be outlined, and an optimization methodology will be presented. Finally, it will be shown that gate process integration, in particular BARC- and POLY-etching, is increasing the i-W CD non-uniformity. This is affecting the ELM-results, despite the high precision and repeatability of these measurements. This ELM-variation, as well as the overall i-W CD non- uniformity should be taken into account when using ELM or CD-SEM as a metrology tool for process window characterization.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ivan K.A. Pollentier, Ivan K.A. Pollentier, Christiaan Baert, Christiaan Baert, Thomas Marschner, Thomas Marschner, Kurt G. Ronse, Kurt G. Ronse, Grozdan Grozev, Grozdan Grozev, Mario Reybrouck, Mario Reybrouck, "Intrawafer CD control in state-of-the-art lithography", Proc. SPIE 3679, Optical Microlithography XII, (26 July 1999); doi: 10.1117/12.354406; https://doi.org/10.1117/12.354406

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