The potential of EUV lithography

Levinson, Harry

doi:10.1117/12.2528446

Cited by 9 publications

(6 citation statements)

References 33 publications

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“…4 To avoid metal diffusion, reaction temperature during "back-end" fabrication is limited to <400 °C, 3 putting stringent demands on surface chemical processes. Advanced 13.5 nm extreme UV (EUV) lithography can address some of these challenges, but equipment costs are expected to be substantial, 5 especially when multiple EUV steps are needed. Also, alignment problems will become more acute in future 3D devices being considered to overcome impending obstacles of silicon memory density and computing energy consumption.…”

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confidence: 99%

Multimaterial Self-Aligned Nanopatterning by Simultaneous Adjacent Thin Film Deposition and Etching

et al. 2021

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Printed component sizes in electronic circuits are approaching 10 nm, but inherent variability in feature alignment during photolithography poses a fundamental barrier for continued device scaling. Deposition-based self-aligned patterning is being introduced, but nuclei defects remain an overarching problem. This work introduces low-temperature chemically self-aligned film growth via simultaneous thin film deposition and etching in adjacent regions on a nanopatterned surface. During deposition, nucleation defects are avoided in nongrowth regions because deposition reactants are locally consumed via sacrificial etching. For a range of materials and process conditions, thermodynamic modeling confirms that deposition and etching are both energetically favorable. We demonstrate nanoscale patterning of tungsten at 220 °C with simultaneous etching of TiO2. Area selective deposition (ASD) of the sacrificial TiO2 layer produces an orthogonal sequence for self-aligned patterning of two materials on one starting pattern, i.e., TiO2 ASD on SiO2 followed by W ASD on Si–H. Experiments also show capacity for self-aligned dielectric patterning via favorable deposition of AlF3 on Al2O3 at 240 °C with simultaneous atomic layer etching of sacrificial ZnO. Simultaneous deposition and etching provides opportunities for low-temperature bottom-up self-aligned patterning for electronic and other nanoscale systems.

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confidence: 99%

Multimaterial Self-Aligned Nanopatterning by Simultaneous Adjacent Thin Film Deposition and Etching

et al. 2021

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“…Resists meeting resolution requirements, with low levels of defects from stochastic phenomena and pattern collapse Light sources that can support photon shot noise and productivity requirements Solutions for meeting small depths-of-focus at 0.55 NA Polarization control for maintaining high contrast at 0.55 NA Computational lithography capabilities Mask making and metrology infrastructure Solutions for large dies Cost of high-NA EUV lithography Table III. 21,22) These are important considerations, since all elements of a lithographic process must be capable in order for the process to be useable in manufacturing. More detail on these challenges is provided in the remainder of this section.…”

Section: Key Challengesmentioning

confidence: 99%

High-NA EUV lithography: current status and outlook for the future

Levinson¹

2022

Jpn. J. Appl. Phys.

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High-NA extreme ultraviolet (EUV) lithography is currently in development. Fabrication of exposure tools and optics with a numerical aperture (NA) equal to 0.55 has started at ASML and Carl Zeiss. Lenses with such high NA will have very small depths-of-focus, which will require improved focus systems and significant improvements in wafer flatness during processing. Lenses are anamorphic to address mask 3D issues, which results in wafer field sizes of 26 mm × 16.5 mm, half that of lower NA EUV tools and optical scanners. Production of large die will require stitching. Computational infrastructure is being created to support high-NA lithography, including simulators that use Tatian polynomials to characterize the aberrations of lenses with central obscurations. High resolution resists that meet the line-edge roughness (LER) and defect requirements for high-volume manufacturing (HVM) also need to be developed. High power light sources will also be needed to limit photon shot noise.

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“…209 Given that the photon shot noise limits the minimum possible LER, resist possessing high optical absorption and quantum efficiency are essential. 210 On the resist side, compositional inhomogeneity is the root cause of manifestation of stochastic phenomenon. Variability in the length of the polymer chains and their spatial distribution can have significant impact on the pattern fidelity.…”

Section: Mitigation Of Stochastic Variations In Patterned Featuresmentioning

confidence: 99%

“…Consequently, for a given exposure dose, a much smaller number of EUV photons are absorbed by fixed volume of a photoresist, making the stochastic variability (also called as photon shot noise) in their position a much larger concern 209 . Given that the photon shot noise limits the minimum possible LER, resist possessing high optical absorption and quantum efficiency are essential 210 . On the resist side, compositional inhomogeneity is the root cause of manifestation of stochastic phenomenon.…”

Section: Perspectives For Euv Lithographymentioning

confidence: 99%

Review of metal-containing resists in electron beam lithography: perspectives for extreme ultraviolet patterning

Saifullah

Tiwale

Ganesan

2022

J. Micro/Nanopattern. Mats. Metro.

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Background: Metal-containing resists entered the mainstream semiconductor industry process flow to mitigate the low absorbance of extreme ultraviolet (EUV) radiation by thin films of organic resists that lead to poor sensitivity and their inability to handle rigors of development and etching conditions.Aim: The long and rich history of using metal-containing resists in electron beam lithography can offer interesting lessons, pointers, and insights to the relatively newcomer EUV lithography, which is slightly over a decade old.Approach: Electron beam lithography has been enjoying a considerable amount of freedom in the choice of resist materials for close to 50 years; especially the use of metal-containing resists to attain not only single digit nanometer resolution, higher sensitivity, and etch resistance but also lower line-edge roughness. Here, we make a comprehensive historical review of the progress made in the patterning of metal-containing resists in electron beam lithography and derive insights that can be potentially useful in EUV patterning.Perspectives: Small molecular weight resists are proven to be crucial for achieving higher resolution with low line-edge roughness. Simplifying process flow by reducing etch-stack-layers is conceivable with metal-containing resists, along with direct-patterning of functional materials for heterogeneous integration. Efficient contact hole patterning at tighter pitches may be incumbent on progress in positive-tone resist research.

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The potential of EUV lithography

Cited by 9 publications

References 33 publications

Multimaterial Self-Aligned Nanopatterning by Simultaneous Adjacent Thin Film Deposition and Etching

Multimaterial Self-Aligned Nanopatterning by Simultaneous Adjacent Thin Film Deposition and Etching

High-NA EUV lithography: current status and outlook for the future

Review of metal-containing resists in electron beam lithography: perspectives for extreme ultraviolet patterning

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