3D mask effects in high NA EUV imaging

Erdmann, Andreas; Evanschitzky, Peter; Bottiglieri, Gerardo; Setten, Eelco van; Fliervoet, Timon

doi:10.1117/12.2515678

Cited by 26 publications

(25 citation statements)

References 9 publications

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“…The next two subsections present simulation results for vertical L/S with a pitch of 32 nm, i.e., a critical situation that is known to provide very low NILS for the imaging of TaBN-based absorbers with the high NA system. 7 Note that this is not the smallest pitch that can be resolved by the high NA EUV system. The shape of the leaves in the dipole illumination and the resulting positions of the diffraction orders are indicated in the pupil diagrams in the insets of Figs.…”

Section: Parametric Analysis Of Selected Critical Use Casesmentioning

confidence: 99%

Perspectives and tradeoffs of absorber materials for high NA EUV lithography

Erdmann

Mesilhy

Evanschitzky

et al. 2020

J. Micro/Nanolith. MEMS MOEMS

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Next-generation extreme ultraviolet (EUV) systems with numerical apertures of 0.55 have the potential to provide sub-8-nm half-pitch resolution. The increased importance of stochastic effects at smaller feature sizes places further demands on scanner and mask to provide high contrast images. We use rigorous mask diffraction and imaging simulation to understand the impact of the EUV mask absorber and to identify the most appropriate optical parameters for high NA EUV imaging. Simulations of various use cases and material options indicate two main types of solutions: high extinction materials, especially for lines spaces, and low refractive index materials that can provide phase shift mask solutions. EUV phase masks behave very different from phase shift masks for DUV. Carefully designed low refractive index materials and masks can open up a new path toward high contrast edge printing. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 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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Section: Parametric Analysis Of Selected Critical Use Casesmentioning

confidence: 99%

Perspectives and tradeoffs of absorber materials for high NA EUV lithography

Erdmann

Mesilhy

Evanschitzky

et al. 2020

J. Micro/Nanolith. MEMS MOEMS

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“…A technical issue specific to EUVL is mask 3D effects, (Erdmann et al 2019) which have three main causes. The first is non-telecentricity, such that the chief ray does not illuminate the mask perpendicularly but rather obliquely at an angle of 6 (in the case of an NA of 0.33).…”

Section: Optical Illumination Systemsmentioning

confidence: 99%

Advances in Optics and Exposure Devices Employed in Excimer Laser/EUV Lithography

Suzuki¹

2020

Handbook of Laser Micro- And Nano-Engineering

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Semiconductor lithography currently provides a resolution close to 10 nm, with the aim of producing extremely fine patterning. Over the last decade, lithography techniques have progressed from ArF immersion to multiple patterning to extreme ultraviolet lithography (EUVL) operating at a wavelength of 13.5 nm. During this period, the first-generation lithography devices were immersion systems and achieved 40 nm resolution through a 1.35 numerical aperture (NA) projection lens in conjunction with an ArF laser (operating at 193 nm) and water immersion. To make full use of the capability of the projection lens, A. Suzuki (*) Head quarter, AS Lithography Consulting

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“…High aspect absorber induces several mask 3D effects, such as critical dimension (CD) difference between horizontal and vertical lines and focus-dependent pattern shift. 1,2 Another example of the EUV mask 3D effect is the deviation of the phase-shift value near the absorber edges (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Fast EUV lithography simulation using convolutional neural network

Tanabe

Sato

Takahashi

2021

J. Micro/Nanopattern. Mats. Metro.

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Background: Thin mask model has been conventionally used in optical lithography simulation. In extreme ultraviolet (EUV) lithography thin mask model is not valid because the absorber thickness is comparable to the mask pattern size. Rigorous electromagnetic (EM) simulations have been used to calculate the thick mask amplitudes. However, these simulations are highly time consuming.Aim: Proposing a prototype of a convolutional neural network (CNN) which reduces the calculation time of rigorous EM simulations in a small mask area with specific mask patterns.Approach: We construct a CNN which reproduces the results of the EM simulation. We define mask 3D amplitude as the difference between the thick mask amplitude and the thin mask amplitude. The mask 3D amplitude of each diffraction order is approximated using three parameters which represent the on-axis and the off-axis mask 3D effects. The mask 3D parameters of all diffraction orders are trained by a CNN. Results:The input and the targets of the CNN are a cut-mask pattern and mask 3D parameters calculated by the EM simulation, respectively. After the training with 199,900 random cut-mask patterns, the CNN successfully predicts the mask 3D parameters of new cut-mask patterns.Conclusions: We construct a CNN which predicts the diffraction amplitudes from 2D EUV mask patterns. After the training, the CNN successfully reproduces the mask 3D amplitude. CNN prediction is 5000 times faster than the rigorous EM simulation. Next challenge is to construct a practical CNN which covers a large area with general mask patterns.

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3D mask effects in high NA EUV imaging

Cited by 26 publications

References 9 publications

Perspectives and tradeoffs of absorber materials for high NA EUV lithography

Perspectives and tradeoffs of absorber materials for high NA EUV lithography

Advances in Optics and Exposure Devices Employed in Excimer Laser/EUV Lithography

Fast EUV lithography simulation using convolutional neural network

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