19 May 2008 The study to optimize CD uniformity by reliable area CD measurement on 45nm D/R DRAM
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Proceedings Volume 7028, Photomask and Next-Generation Lithography Mask Technology XV; 70281O (2008) https://doi.org/10.1117/12.793065
Event: Photomask and NGL Mask Technology XV, 2008, Yokohama, Japan
Abstract
As design rule of memory device is shrinking, the various errors obtained by process, such as line edge roughness, local CD variation and electron beam shot placement error, are significant to CD measurement results on mask and wafer. Reliable CD measurement is needed to represent real feature size of mask and wafer results in high accurate CD target and uniformity by various CD correction techniques before mask fabrication and after. Recently light transmittance control technique on mask has been introduced, which reduce the field CD variation of wafer [1]. To correct the wafer field CD uniformity by selective control of the light transmittance of mask, good correlation of mask CD and wafer field CD is important [2][3]. AIMS (aerial image measurement and simulation) or light intensity uniformity of inspection tools or other light intensity measurement tools are generally used to measure mask CD uniformity on mask. In this study, mask CD uniformity measured by CD-SEM was used to compensate the field CD variation on wafer, by enhancing the correlation between wafer field CD uniformity and mask using spatial filtering of SEM image and area CD measurement concept. Expected residual error of wafer field CD error using correction of mask CD uniformity were compared to wafer CD variation by selective light correction using wafer CD uniformity map.
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Yongkyoo Choi, Sunghyun Oh, Munsik Kim, Yongdae Kim, Changreol Kim, "The study to optimize CD uniformity by reliable area CD measurement on 45nm D/R DRAM", Proc. SPIE 7028, Photomask and Next-Generation Lithography Mask Technology XV, 70281O (19 May 2008); doi: 10.1117/12.793065; https://doi.org/10.1117/12.793065
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