Experimental local MEEF study using programmed mask variability on hexagonal pitch 40 nm contact hole arrays

Lieve Van Look; Joern-Holger Franke; Andreas Frommhold; Alberto Colina; Gijsbert Rispens

doi:10.1117/12.2658714

28 April 2023 Experimental local MEEF study using programmed mask variability on hexagonal pitch 40 nm contact hole arrays

Lieve Van Look, Joern-Holger Franke, Andreas Frommhold, Alberto Colina, Gijsbert Rispens

Author Affiliations +

Proceedings Volume 12494, Optical and EUV Nanolithography XXXVI; 124940N (2023) https://doi.org/10.1117/12.2658714
Event: SPIE Advanced Lithography + Patterning, 2023, San Jose, California, United States

Abstract

Control of the Local Critical Dimension Uniformity (LCDU) and the associated Edge Placement Error of contact holes (CHs) is important for the implementation of EUV lithography in high-volume production today and for future nodes. The Systematic part of the LCDU is governed by the local CD variation on the mask, multiplied with a Mask Error Enhancement Factor (MEEF). Recent studies have shown that the relevant MEEF to predict the LCDU systematics is the Local MEEF, where not all CHs grow at the same time. This stands in contrast to the more commonly used Global MEEF, that quantifies the wafer CD impact of all CHs growing simultaneously on mask. In this work, we experimentally study how the systematic LCDU, and the Local and Global MEEF depend on illumination condition and mask variability strengths and signatures. We expose a test mask with programmed local CD variability on an NXE:3400 exposure tool and perform anchored CDSEM metrology on the mask and on wafer. Our results show that the illumination condition and the local mask CD fingerprint impact the Global and Local MEEF independently in a non-trivial way. Two pupils with similar Global MEEF show a 55% difference in Local MEEF and systematic LCDU component. Optimizing the pupil for Global MEEF therefore does not guarantee an optimum Local MEEF (or Systematic LCDU).

Conference Presentation

Citation Download Citation

Lieve Van Look, Joern-Holger Franke, Andreas Frommhold, Alberto Colina, and Gijsbert Rispens "Experimental local MEEF study using programmed mask variability on hexagonal pitch 40 nm contact hole arrays", Proc. SPIE 12494, Optical and EUV Nanolithography XXXVI, 124940N (28 April 2023); https://doi.org/10.1117/12.2658714

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