Progress in EUV-interference lithography resist screening towards the deployment of high-NA lithography

Abstract

The development of EUV resists is one of the major challenges for the deployment of high-NA EUV lithography , which is on the roadmap for high-volume manufacturing of future semiconductor technology nodes. Resist performance is admittedly governed by a resolution-roughness-sensitivity (RLS) tradeoff. This study reports on the EUV resist progress achieved during the last year in the framework of the resist screening program by PSI and ASM L. An extensive performance characterization of different resists was carried out using the XIL-II beamline EUV interference lithography (EUV-IL) tool at the Swiss Light Source (SLS). We present the upgraded screening metrology used in 2020 at PSI enabling increased confidence in results. We report material performance towards patterning lines/spaces features with respect to the key parameters of RLS: half-pitch (HP), dose-to-size (DtS), line-width-roughness (LWR), as well as Z-factor for overall performance consideration. General progress in EUV resist development is reviewed by considering several resist platforms available today from different vendors. Different molecular and chemically amplified resist materials are demonstrated as viable for 16 nm resolution technology nodes. One chemically-amplified resist vendor shows suitable materials for 13-nm-resolution technologies while exhibiting potential for further downscaling. We present different metal-oxide resists screening with resolutions down to 10 nm HP. We finally discuss the overall progress of materials achieved between 2019 and 2020 towards reaching high-NA.

International Roadmap for Devices and Systems lithography roadmap

“…But some recent papers have shown quite spectacular improvements in resists for particular applications or particular imaging conditions. 20 Part of this dichotomy may be because there two classes of EUV resists in current use. There are chemically amplified resists that use mostly or all organic chemistry and there are mostly inorganic resists that use metal oxides as the key EUV imaging component.…”

Chemical reactions induced by low-energy electron exposure on a novel inorganic-organic hybrid dry EUV photoresist deposited by molecular atomic layer deposition (MALD)

“…As the industry prepares to move toward the next generation of EUV lithography (EUVL) and beyond the 5-nm node, demand for thinner resist with high performance is continuously growing. [3][4][5][6] However, thinning of traditional, spin-coated polymer-based resists alone would not address challenges related to materials sensitivity and the pattern transfer process for the next generation EUVL. 7 A solution to such shortcomings is to incorporate high-EUV absorbing inorganic elements into the organic matrix, forming hybrid materials, which help enhance the sensitivity and mechanical strength of photoresists.…”

Nanometrology for evaluating rare sites for molecular homogeneity

“…The current road map 3 indicates that over the next decade the need for nanoscale molecular characterization will become acutely important due to the introduction of high numerical aperture extreme ultraviolet, EUV, resist patterning, which is capable of producing patterns with sub-10 nm half pitches. [4][5][6][7] In these tiny features, two types of variations affect the device quality: shot noise during irradiation and chemical variability in the resist. [8][9][10] The latter has been generally perceived as a "black box" as it was difficult or impossible to track the molecular composition at the nanoscale.…”