19 May 2008 Practical application of aerial imaging mask inspection for memory devices
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Proceedings Volume 7028, Photomask and Next-Generation Lithography Mask Technology XV; 70281G (2008) https://doi.org/10.1117/12.793057
Event: Photomask and NGL Mask Technology XV, 2008, Yokohama, Japan
Abstract
A major challenge of low-k1 microlithography that has to be addressed by any photomask defect detection strategy is the complex relation between the signal of the defect in the detector and its impact, in terms of printing errors, on the processed wafer. This non-trivial relation is immanent to the large MEEF values characterizing lithography at sub-wavelength features. One common method to work around this problem is to use aerial imaging optics which emulates the stepper exposure process. Currently available aerial inspection and review tools based on the well established fact that CD variation in the aerial image closely represents the CD variation on the wafer. Published literature explains why a defect's printing effect can be captured, with high correlation, by aerial imaging optics. Here we describe a novel connection between a defect's detection signal and the printed CD variation on an adjacent pattern. This connection can be exploited by aerial imaging mask inspection systems to ensure that their detection thresholds are set to detect CD variation of a given threshold. We show that under aerial imaging conditions, the defect signal and CD variation are linearly related, regardless of defect's attributes, provided that the defect resides close to a pattern's transition edge, or is surrounded by a dense pattern. We present experimental results, demonstrating this linear scaling between the defect signal and CD variation, and show practical application results of aerial imaging mask inspection, with implications to production mask fab.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Hyun Joo Baik, Hyun Joo Baik, Dong Hoon Chung, Dong Hoon Chung, Yong Hoon Kim, Yong Hoon Kim, Han Ku Cho, Han Ku Cho, Amir Sagiv, Amir Sagiv, Shmoolik Mangan, Shmoolik Mangan, Ziv Parizat, Ziv Parizat, Eun Young Park, Eun Young Park, Yaniv Brami, Yaniv Brami, Dana Bernstein, Dana Bernstein, } "Practical application of aerial imaging mask inspection for memory devices", Proc. SPIE 7028, Photomask and Next-Generation Lithography Mask Technology XV, 70281G (19 May 2008); doi: 10.1117/12.793057; https://doi.org/10.1117/12.793057
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