Fabrication of sub 45 nm random patterns through centerline phase-shifting mask (CL-PSM)

Jeung-woo Lee; Seiji Matsuura; Kiyoshi Fujii

doi:10.1117/12.599309

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12 May 2005 Fabrication of sub 45 nm random patterns through centerline phase-shifting mask (CL-PSM)

Jeung-woo Lee, Seiji Matsuura, Kiyoshi Fujii

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Proceedings Volume 5754, Optical Microlithography XVIII; (2005) https://doi.org/10.1117/12.599309
Event: Microlithography 2005, 2005, San Jose, California, United States

Abstract

Centerline phase-shifting mask (CL-PSM), which has narrow chromium lines at the boundaries of a μ-phase shifter, is promising as a resolution enhancement technology for random-pitch line patterns. We compared the performance of the CL-PSM in fabricating sub-45 nm lines with that of the chrome-less phase-shifting mask (CLM) in 157-nm lithography. The simulation results showed the CL-PSM is superior to the CLM in resolution and depth of focus (DOF), especially in small pitch patterns. We optimized the layouts of CL-PSM and the CLM to 40-nm-wide, 140-nm-pitch line patterns through the simulation. In exposure experiments with optimized masks, the CL-PSM resolved 40-nm-wide line patterns with a minimum pitch of 110 nm, while the resolvable minimum pitch was 130 nm for the CLM. The DOFs for 40-nm-wide, 140-nm-pitch lines were 200 and 80 nm with CL-PSM and CLM, respectively. Furthermore, we estimated the resolution limit of CL-PSM in hyper-NA 193-nm lithography, and showed a pitch of 100 nm would be achieved with a 1.4 NA optics.

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Jeung-woo Lee, Seiji Matsuura, and Kiyoshi Fujii "Fabrication of sub 45 nm random patterns through centerline phase-shifting mask (CL-PSM)", Proc. SPIE 5754, Optical Microlithography XVIII, (12 May 2005); https://doi.org/10.1117/12.599309

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