High resolution hole patterning with EB lithography for NIL template production

Tanabe, Mana; Yagawa, Keisuke; Motokawa, Takeharu; Hagihara, Kazuki; Suenaga, Machiko; Saito, Masato; Kanamitsu, Shingo; Itoh, Masamitsu

doi:10.1117/12.2242363

Cited by 2 publications

(1 citation statement)

References 3 publications

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“…Higher-resolution large-area patterns are currently manufactured by complementing photolithography (PL) with self-aligned double patterning (SADP) and multiple lithography-etch steps. Directed self-assembly (DSA) is also being explored; however, both SADP and DSA are primarily restricted to periodic features [9][10][11] . Although the highest-resolution e-beam processes (Gaussian beam tools with nonchemically amplified resists) can achieve <5 nm resolution [12][13][14] , this is only available at very low throughputs.…”

Section: Introductionmentioning

confidence: 99%

Extending the resolution limits of nanoshape imprint lithography using molecular dynamics of polymer crosslinking

et al. 2021

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Emerging nanoscale applications in energy, electronics, optics, and medicine can exhibit enhanced performance by incorporating nanoshaped structures (nanoshape structures here are defined as shapes enabled by sharp corners with radius of curvature < 5 nm). Nanoshaped fabrication at high-throughput is well beyond the capabilities of advanced optical lithography. Although the highest-resolution e-beams and large-area e-beams have a resolution limit of 5 and 18 nm half-pitch lines or 20 nm half-pitch holes, respectively, their low throughput necessitates finding other fabrication techniques. By using nanoimprint lithography followed by metal-assisted chemical etching, diamond-like nanoshapes with ~3 nm radius corners and 100 nm half-pitch over large areas have been previously demonstrated to improve the nanowire capacitor performance (by ~90%). In future dynamic random-access memory (DRAM) nodes (with DRAM being an exemplar CMOS application), the implementation of nanowire capacitors scaled to <15 nm half-pitch is required. To scale nanoshape imprint lithography down to these half-pitch values, the previously established atomistic simulation framework indicates that the current imprint resist materials are unable to retain the nanoshape structures needed for DRAM capacitors. In this study, the previous simulation framework is extended to study improved shape retention by varying the resist formulations and by introducing novel bridge structures in nanoshape imprinting. This simulation study has demonstrated viable approaches to sub-10 nm nanoshaped imprinting with good shape retention, which are matched by experimental data.

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Section: Introductionmentioning

confidence: 99%

Extending the resolution limits of nanoshape imprint lithography using molecular dynamics of polymer crosslinking

et al. 2021

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Molecular dynamics modeling framework for overcoming nanoshape retention limits of imprint lithography

Cherala¹,

Sreenivasan²

2018

Microsyst Nanoeng

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Complex nanoshaped structures (nanoshape structures here are defined as shapes enabled by sharp corners with radius of curvature <5 nm) have been shown to enable emerging nanoscale applications in energy, electronics, optics, and medicine. This nanoshaped fabrication at high throughput is well beyond the capabilities of advanced optical lithography. While the highest-resolution e-beam processes (Gaussian beam tools with non-chemically amplified resists) can achieve <5 nm resolution, this is only available at very low throughputs. Large-area e-beam processes, needed for photomasks and imprint templates, are limited to ~18 nm half-pitch lines and spaces and ~20 nm half-pitch hole patterns. Using nanoimprint lithography, we have previously demonstrated the ability to fabricate precise diamond-like nanoshapes with ~3 nm radius corners over large areas. An exemplary shaped silicon nanowire ultracapacitor device was fabricated with these nanoshaped structures, wherein the half-pitch was 100 nm. The device significantly exceeded standard nanowire capacitor performance (by 90%) due to relative increase in surface area per unit projected area, enabled by the nanoshape. Going beyond the previous work, in this paper we explore the scaling of these nanoshaped structures to 10 nm half-pitch and below. At these scales a new “shape retention” resolution limit is observed due to polymer relaxation in imprint resists, which cannot be predicted with a linear elastic continuum model. An all-atom molecular dynamics model of the nanoshape structure was developed here to study this shape retention phenomenon and accurately predict the polymer relaxation. The atomistic framework is an essential modeling and design tool to extend the capability of imprint lithography to sub-10 nm nanoshapes. This framework has been used here to propose process refinements that maximize shape retention, and design template assist features (design for nanoshape retention) to achieve targeted nanoshapes.

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High resolution hole patterning with EB lithography for NIL template production

Cited by 2 publications

References 3 publications

Extending the resolution limits of nanoshape imprint lithography using molecular dynamics of polymer crosslinking

Extending the resolution limits of nanoshape imprint lithography using molecular dynamics of polymer crosslinking

Molecular dynamics modeling framework for overcoming nanoshape retention limits of imprint lithography

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