Optimisation of EUV mask absorbing layers

Robic, Jean-Yves; Schiavone, Patrick; Rodillon, Vincent; Payerne, Renaud

doi:10.1016/s0167-9317(02)00443-4

Cited by 7 publications

(2 citation statements)

References 7 publications

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“…1, a semiconductor chip is fabricated by reflecting= absorbing EUV from each of the masks. [8][9][10] EUVL systems use reflective and absorbing masks that absorb a significant amount of incident EUV, and the required illumination energy increases at higher throughput requirements. This high-energy illumination can deform EUV masks, pellicles, and wafers due to strong light absorption in most materials.…”

Section: Introductionmentioning

confidence: 99%

Modeling of thermomechanical changes of extreme-ultraviolet mask and their dependence on absorber variation

Ban¹,

Park²,

Park³

et al. 2018

Jpn. J. Appl. Phys.

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Thermal and structural deformation of extreme-ultraviolet lithography (EUVL) masks during the exposure process may become important issues as these masks are subject to rigorous image placement and flatness requirements. The reflective masks used for EUVL absorb energy during exposure, and the temperature of the masks rises as a result. This can cause thermomechanical deformation that can reduce the pattern quality. The use of very thick low-thermal-expansion substrate materials (LTEMs) may reduce energy absorption, but they do not completely eliminate mask deformation. Therefore, it is necessary to predict and optimize the effects of energy transferred from the extreme-ultraviolet (EUV) light source and the resultant patterns of structured EUV masks with complex multilayers. Our study shows that heat accumulates in the masks as exposure progresses. It has been found that a higher absorber ratio (pattern density) applied to the patterning of EUV masks exacerbates the problem, especially in masks with more complex patterns.

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Section: Introductionmentioning

confidence: 99%

Modeling of thermomechanical changes of extreme-ultraviolet mask and their dependence on absorber variation

Ban¹,

Park²,

Park³

et al. 2018

Jpn. J. Appl. Phys.

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“…Therefore, many works have been focused on the absorber design to maximize the optical performance [8][9][10][11][12][13][14][15][16]. Among the various optical properties, the reflectivity and aerial image intensity were directly related to the pattern printability of the EUVL system [17][18].…”

Section: Introductionmentioning

confidence: 99%

Numerical modeling of absorber characteristics for EUVL

Kang

Ahn

et al. 2006

SPIE Proceedings

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The characteristics of various potential absorbers, such as Cr, Ta, and TaN materials were quantitatively investigated by calculating the optical contrast and geometrical width variation of pattern image of 25-nm-width transferred through the exposure system. The intrinsic absorber performance was evaluated by the numerical modeling of the reflectivity on the mask and the aerial image intensity on the wafer. The reflectivity on the mask was calculated for various absorber thicknesses (40-70 nm) using Fresnel equation. For the calculation of the aerial image intensity of pattern features with various absorbers, SOLID-EUV, which is capable of rigorous electromagnetic field computation, was employed. It could be reasonably concluded that the TaN absorber model showed superior optical characteristics compared to other absorber systems, whereas the best performance on the geometrical characteristics was found in the Ta absorber system.

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Dry etching of extreme ultraviolet lithography mask structures in inductively coupled plasmas

Kim¹,

Lee²,

Jung³

et al. 2008

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Extreme ultraviolet lithography (EUVL) is currently being examined for its potential use in the next generation of lithography techniques. Among the core EUVL technologies, mask fabrication is of considerable importance due to the use of new reflective optics. This study investigated the etching properties of EUVL mask materials, such as Al2O3 antireflection coating (ARC), TaN (absorber layer) and Ru (buffer/capping layer), by varying the Cl2∕Ar gas flow ratio, dc self-bias voltage (Vdc) and top electrode power in inductively coupled plasma. The Al2O3 (ARC) layer could be etched with an etch selectivity approaching 0.5 over the TaN absorber layer. The ARC/TaN stack could be etched with an infinitely high etch selectivity over the Ru layer. Etching of the stacked mask structures with a 200nm line/space hydrogen silsesquioxane e-beam resist pattern showed a profile angle of 85° and an etch stop on the Ru buffer/capping layer.

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Optimisation of EUV mask absorbing layers

Cited by 7 publications

References 7 publications

Modeling of thermomechanical changes of extreme-ultraviolet mask and their dependence on absorber variation

Modeling of thermomechanical changes of extreme-ultraviolet mask and their dependence on absorber variation

Numerical modeling of absorber characteristics for EUVL

Dry etching of extreme ultraviolet lithography mask structures in inductively coupled plasmas

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