Understanding Extreme Stochastic Events in EUV Resists

Naulleau, Patrick; Bhattarai, Suchit; Neureuther, Andrew R.

doi:10.2494/photopolymer.30.695

Cited by 6 publications

(4 citation statements)

References 16 publications

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“…A high level of photo-decomposable base might also help reduce this effect. This analysis is not tractable algebraically so simulation with the Multivariate Poisson Propagation Model (MPPM) simulator developed by Naulleau et al 11 with a 3D level set surface etching model added by Long et al 12 will be used.…”

Section: Mppm Simulation Of Missing Contactsmentioning

confidence: 99%

Diagnosing phenomena that influence missing contacts and pillars

Neureuther

Long²,

Wallraff³

et al. 2022

International Conference on Extreme Ultraviolet Lithography 2022

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Algebraic models using Poisson statistics are used to investigate phenomena contributing to missing contacts and pillars, assess progress in their mitigation, and provide guidance for technology pathfinding for sub-10nm. Fitting the missing rate versus dose clearly shows the dominant EUV photon absorption stochastics, enables scaling from 10 -4 to 10 -13 error rates, and gives an equivalent number of dissolution aiding events for diagnosing physical phenomena. This number for 20 nm contacts in CAR is about 300 and suggest the possible presence of reaction enhanced diffusion or reaction enhanced solvent penetration and gel extrusion prior to disentanglement dissolution. Metal oxide resists are more complex and data on missing pillars is just becoming available. The use of similar characterization techniques can pursue phenomena that are more Gaussian in nature and more beneficial for reducing error rates.

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Section: Mppm Simulation Of Missing Contactsmentioning

confidence: 99%

Diagnosing phenomena that influence missing contacts and pillars

Neureuther

Long²,

Wallraff³

et al. 2022

International Conference on Extreme Ultraviolet Lithography 2022

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show abstract

“…While the core stochastic details of the model mirror those of the 2D MPPM, and are detailed elsewhere, [5][6][7] a few of the key features will be summarized here. The MPPM is an "error" propagation model, whereby the initial distribution of resist components and photons are treated as random variables (RVs).…”

Section: Model Detailsmentioning

confidence: 99%

“…Figure 7 shows that changing z-blur has the effect of biasing the mean contact CD. To use the line of thinking presented by Naulleau et al, 6 one may wonder whether the improvement in CD distribution arises from an increase in acid amplification due to the increased z diffusion. This increased amplification could bias the mean CD away from the nonlinear dose response of the resist, which would in turn mitigate the skew of the CD distribution.…”

Section: Exposure Latitude and CD Biasingmentioning

confidence: 99%

Three-dimensional modeling of EUV photoresist using the multivariate Poisson propagation model

Long

Neureuther

Naulleau

2021

J. Micro/Nanopattern. Mats. Metro.

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Background: As target feature sizes for EUV lithography shrink, it is becoming ever more important to understand the intricate details of photoresist materials, including the role of the "third dimension"-the dimension perpendicular to the wafer. With resist thicknesses shrinking toward the single-digit nanometer scale alongside target linewidths, small changes in resist performance in this dimension will have a greater overall effect on pattern quality.Aim: To use modeling to understand the effect that the third dimension has on resist performance, in particular the interplay between the third dimension and resist stochastics.Approach: We developed a three-dimensional version of the multivariate Poisson propagation model, a stochastic resist simulator. As a test case for the model, we explore the role of acid diffusion in the so-called third dimension by simulating 10 5 vias at a series of z-blur conditions.Results: Our model suggests that increased z-blur yields an improvement in both dose to size and pattern uniformity without sacrificing resolution. Conclusions:We have developed a 3D resist model that can simulate large numbers of contacts. Early results from the 3D model show improved patterning performance can be achieved by increasing the z-blur.

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“…In pursuit of further miniaturization of semiconductor integrated circuit devices by projection lithography using extreme ultraviolet (EUV) light at 13-nm wavelength, stochastic pattern defect problems have arisen. [1][2][3] As the feature size of circuit patterns (∼10 nm) is approaching to the size of resist molecule/polymer (1 to 2 nm), nanometer level roughness on pattern edges (often called line edge roughness, LER) becomes a problem. 4,5 In contrast, the stochastic defects are fatal patterning failures such as bridging between neighboring lines or breakages of lines.…”

Section: Introductionmentioning

confidence: 99%

Localized and cascading secondary electron generation as causes of stochastic defects in extreme ultraviolet projection lithography

Fukuda

2019

J. Micro/Nanolith. MEMS MOEMS

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Projection lithography using extreme ultraviolet (EUV) light at 13-nm wavelength is expected to achieve production of integrated circuits below 10 nm design-rules. In pursuit of further miniaturization, however, stochastic pattern defect problems have arisen. Here, we discuss the possible impact of spatially inhomogeneous secondary electron (SE) generation on stochastic defects. Two mechanisms are investigated: (1) accidental connections of photon shot noises enhanced by densely localized SE generation and (2) cascading SE generation along photoelectron trajectory traveling from pattern edge into a dark region. Since such defect probabilities are extremely low (typically 10 −4 to ∼10 −12), results of Monte Carlo simulation based on classical optical image and electron scattering simulations are converted into probability functions for densities of physical/chemical events such as photon absorption, SE generation, and elementary reaction in chemically amplified resists. Probabilities of pattern formation and of defect generation are modeled using these functions. Results of performance optimization using a multiobjective genetic algorithm show higher stochastic defects probability in EUV than in conventional deep-UV exposure due to larger spatial inhomogeneity in reaction density and existence of SE generation strings. Defect probabilities are strongly dependent on absolute pattern sizes in the two mechanisms, regardless of the resolution capability of imaging systems. Guidelines for suppressing stochastic defects are suggested, such as homogenization of reaction density, material composition for increasing scattering crosssection, and suppression of pattern edge fluctuation.

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Understanding Extreme Stochastic Events in EUV Resists

Cited by 6 publications

References 16 publications

Diagnosing phenomena that influence missing contacts and pillars

Diagnosing phenomena that influence missing contacts and pillars

Three-dimensional modeling of EUV photoresist using the multivariate Poisson propagation model

Localized and cascading secondary electron generation as causes of stochastic defects in extreme ultraviolet projection lithography

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