19 March 2015 CD uniformity improvement of dense contact array in negative tone development process
Author Affiliations +
Abstract
Layout pattern density impacts mask critical dimension uniformity (MCDU) as well as wafer critical dimension uniformity (WCDU) performances in some aspects. In patterning the dense contact array with negative tone development (NTD) process, the abrupt pattern density change around the array edge of a NTD clear tone reticle arises as a very challenging issue for achieving satisfactory WCDU. Around the array boundary, apart from the MCDU greatly impacted by the abrupt pattern density change, WCDU in lithographic process is also significantly influenced by the optical flare and chemical flare effects. This study investigates the pattern density effect induced MCDU and WCDU variations. Various pattern densities are generated by the combination of fixed array pattern and various sub-resolution assist feature (SRAF) extension regions for quantifying the separated WCD variation budget contributed by MCD variation, chemical flare effect and optical flare effect. With the proper pattern density modulation outside the array pattern on a clear tone reticle, MCD variation across array can be eliminated, optical flare and chemical flare effects induced WCD variation is also greatly suppressed.
© (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Fengnien Tsai, Teng-hao Yeh, C. C. Yang, Elvis Yang, T. H. Yang, K. C. Chen, "CD uniformity improvement of dense contact array in negative tone development process", Proc. SPIE 9424, Metrology, Inspection, and Process Control for Microlithography XXIX, 94242J (19 March 2015); doi: 10.1117/12.2083674; https://doi.org/10.1117/12.2083674
PROCEEDINGS
10 PAGES


SHARE
Back to Top