Comprehensive EUV lithography model

Smith, Mark D.; Graves, Trey; Biafore, John J.; Robertson, Stewart A.; Kim, Cheolkyun; Moon, James; Kim, Jaeheon; Bok, Cheol-Kyu; Yim, Donggyu

doi:10.1117/12.879766

Cited by 10 publications

(11 citation statements)

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“…This is because the dose required and the number of photons used in the slice of photoresist 20nm below the top of the line is the same when it is exposed to a constant CD at that point, no matter how much resist is below that 20nm slice. The simulated values are much higher typically observed experimentally [14], because actual measurements of LWR look down from the top of the resist and effectively do some vertical averaging, thus reducing some of the observed roughness. Figure 2b shows a measurement at the same point on the same lines of resist but using a "weighted" measurement that includes some vertical averaging [15].…”

Section: Noisiness and Graynessmentioning

confidence: 68%

The Physics of EUV Photoresist and How It Drives Strategies for Improvement

Mark¹,

Cho²,

Petrillo³

2012

J. Photopol. Sci. Technol.

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EUV lithography requires high performance resists. The mechanism of light absorbance and acid generation is very different in EUV resists than in previous generations of chemically amplified resists. Resist absorbance must be driven up instead of down, which will require that new elements be incorporated into the resist. Some hafnium-containing resists have shown promise while maintaining a satisfactory etch resistance. These capabilities need to be built upon, and other metals need to be tested. The physics of EUV light and the small feature sizes involved also mean that the industry will be challenged to overcome noisiness, rather than grayness. This will require better understanding of LWR) and likely post-processing treatment of resists to improve the LWR and process windows.

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Section: Noisiness and Graynessmentioning

confidence: 68%

The Physics of EUV Photoresist and How It Drives Strategies for Improvement

Mark¹,

Cho²,

Petrillo³

2012

J. Photopol. Sci. Technol.

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“…The flare in EUV lithography is much more pronounced than in DUV lithography [7]. For simplicity, this paper adopts an approximate flare model based on the constant scattering effect assumption.…”

Section: A Modeling Of the Flare Effectmentioning

confidence: 99%

“…Basically, flare is randomly scattered light from various parts of the optical system with a certain surface roughness. Compared to the 193-nm ArF optical lithography system, EUV lithography suffers from approximately a two hundred times larger flare, since flare levels are inversely proportional to the wavelength squared [7,8]. In addition, similar to DUV lithography, the image fidelity of EUV lithography is affected by the optical proximity effect (OPE) due to diffraction and interference.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, similar to DUV lithography, the image fidelity of EUV lithography is affected by the optical proximity effect (OPE) due to diffraction and interference. Finally, as the light is projected onto the wafer, the photoresist effect must be considered in the image fidelity evaluation [2,7,9]. All of the effects mentioned above can introduce image distortion in the EUV lithography systems and will be considered in this paper.…”

Section: Introductionmentioning

confidence: 99%

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Gradient-based inverse extreme ultraviolet lithography

Ma¹,

Wang²,

Chen³

et al. 2015

Appl. Opt.

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Extreme ultraviolet (EUV) lithography is the most promising successor of current deep ultraviolet (DUV) lithography. The very short wavelength, reflective optics, and nontelecentric structure of EUV lithography systems bring in different imaging phenomena into the lithographic image synthesis problem. This paper develops a gradient-based inverse algorithm for EUV lithography systems to effectively improve the image fidelity by comprehensively compensating the optical proximity effect, flare, photoresist, and mask shadowing effects. A block-based method is applied to iteratively optimize the main features and subresolution assist features (SRAFs) of mask patterns, while simultaneously preserving the mask manufacturability. The mask shadowing effect may be compensated by a retargeting method based on a calibrated shadowing model. Illustrative simulations at 22 and 16 nm technology nodes are presented to validate the effectiveness of the proposed methods.

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“…Flare provides a localized background light intensity which can induce critical dimension (CD) variation and reduce contrast and process window. 5,6 Even though this effect has been studied and is well understood in KrF (248 nm) and ArF (193 nm) lithographies, not much attention has been paid to it recently because the level of flare has been sufficiently suppressed and the resultant impact to lithography processes is small. When the lithography wavelength shifts from 193 to 13.5 nm, flare can no longer be neglected.…”

Section: Introductionmentioning

confidence: 99%

Review of resist-based flare measurement methods for extreme ultraviolet lithography

Sun

Wood

Verduijn³

et al. 2013

J. Micro/Nanolith. MEMS MOEMS

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Abstract. Flare (stray light) is an important effect impacting extreme ultraviolet lithography (EUVL) imaging system performance. Four flare measurement methods including Kirk, modulation transfer function, double exposure, and zonal ring approximation method are reviewed and analyzed theoretically. The point spread function of an EUV NXE:3100 exposure tool is extracted from the measured Kirk flare (KF) and fitted with a double-fractal model. The KF for this NXE:3100 tool is determined to be 8.5% for a 2-μm diameter absorber pad placed in a 12-mm outer radius bright field, which is larger than the previous 5% KF data measured by ASML and IMEC in 2011. The observation of the increased flare level in the NXE:3100 tool suggests that contamination of EUV optics may be a potential problem for EUVL manufacturing. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Comprehensive EUV lithography model

Cited by 10 publications

References 0 publications

The Physics of EUV Photoresist and How It Drives Strategies for Improvement

The Physics of EUV Photoresist and How It Drives Strategies for Improvement

Gradient-based inverse extreme ultraviolet lithography

Review of resist-based flare measurement methods for extreme ultraviolet lithography

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