31 May 2013 Phase defect mitigation strategy: unveiling fiducial mark requirements on extreme ultraviolet lithography masks
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Abstract
For extreme ultraviolet lithography (EUVL), the fabrication of defect free multi-layered (ML) mask blanks is a challenge. ML defects are generated by substrate defects and adders during ML coating and are called phase defects (PDs). If we can accept ML blanks with a certain number of PDs, the blank yield will be drastically increased. We can use fewer PD blanks and reduce PD influence by covering them with an absorber layer. To do this, PDs should be located during ML blank defect inspection before absorber patterning. To locate PDs on blanks accurately and precisely, the fiducial marks (FMs) on ML blanks can be used for mask alignment. The defect location accuracy requirement is below 10 nm. We present the results of a feasibility study on the requirements of FMs on EUVL masking by simulations and experiments to establish a PD mitigation method with the EUV actinic blank inspection tool. Based on the results, the optimum ranges for FM lines etched into the ML are 3 to 5 μm in width and at least 100 nm in depth.
© 2013 Society of Photo-Optical Instrumentation Engineers (SPIE)
Tetsunori Murachi, Tetsunori Murachi, Tsuyoshi Amano, Tsuyoshi Amano, Sung Hyun Oh, Sung Hyun Oh, } "Phase defect mitigation strategy: unveiling fiducial mark requirements on extreme ultraviolet lithography masks," Journal of Micro/Nanolithography, MEMS, and MOEMS 12(2), 023008 (31 May 2013). https://doi.org/10.1117/1.JMM.12.2.023008 . Submission:
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