13 April 2017 Electrical study of DSA shrink process and CD rectification effect at sub-60nm using EUV test vehicle
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In this study, the integrity and the benefits of the DSA shrink process were verified through a via-chain test structure, which was fabricated by either DSA or baseline litho/etch process for via layer formation while metal layer processes remain the same. The nearest distance between the vias in this test structure is below 60nm, therefore, the following process components were included: 1) lamella-forming BCP for forming self-aligned via (SAV), 2) EUV printed guiding pattern, and 3) PS-philic sidewall. The local CDU (LCDU) of minor axis was improved by 30% after DSA shrink process. We compared two DSA Via shrink processes and a DSA_Control process, in which guiding patterns (GP) were directly transferred to the bottom OPL without DSA shrink. The DSA_Control apparently resulted in larger CD, thus, showed much higher open current and shorted the dense via chains. The non-optimized DSA shrink process showed much broader current distribution than the improved DSA shrink process, which we attributed to distortion and dislocation of the vias and ineffective SAV. Furthermore, preliminary defectivity study of our latest DSA process showed that the primary defect mode is likely to be etch-related. The challenges, strategies applied to improve local CD uniformity and electrical current distribution, and potential adjustments were also discussed.
Conference Presentation
© (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Cheng Chi, Cheng Chi, Chi-Chun Liu, Chi-Chun Liu, Luciana Meli, Luciana Meli, Jing Guo, Jing Guo, Doni Parnell, Doni Parnell, Yann Mignot, Yann Mignot, Kristin Schmidt, Kristin Schmidt, Martha Sanchez, Martha Sanchez, Richard Farrell, Richard Farrell, Lovejeet Singh, Lovejeet Singh, Tsuyoshi Furukawa, Tsuyoshi Furukawa, Kafai Lai, Kafai Lai, Yongan Xu, Yongan Xu, Daniel Sanders, Daniel Sanders, David Hetzer, David Hetzer, Andrew Metz, Andrew Metz, Sean Burns, Sean Burns, Nelson Felix, Nelson Felix, John Arnold, John Arnold, Daniel Corliss, Daniel Corliss, } "Electrical study of DSA shrink process and CD rectification effect at sub-60nm using EUV test vehicle", Proc. SPIE 10146, Advances in Patterning Materials and Processes XXXIV, 101460Q (13 April 2017); doi: 10.1117/12.2260454; https://doi.org/10.1117/12.2260454

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