Ruthenium (Ru) peeling and predicting robustness of the capping layer using finite element method (FEM) modeling

Jang, Il Yong; John, Arun; Goodwin, Frank; Lee, Su Young; Kim, Byung Gook; Kim, Seong Sue; Jeon, Chan-Uk; Kim, Jae Hyung; Jang, Yong Hoon

doi:10.1117/12.2069991

Cited by 5 publications

(7 citation statements)

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“…B 4 C is also widely studied as an interdiffusion barrier between Mo and Si for EUV reflective ML mirrors, 27 and as a capping layer of the *Address all correspondence to: Susumu Iida, E-mail: susumu.iida@eidec.co .jp ML. 28 In order to evaluate the PEM image contrast of a lineand-space (L/S) pattern, the SEECs of these materials with 100 nm thickness deposited on quartz substrates were measured using a specially designed scanning Auger microscope. 29 It should be noted that the obtained data were measured in as-is (as-deposited) conditions, with their native oxide films on their surface, in order to demonstrate the actual mask surface condition.…”

Section: Methodsmentioning

confidence: 99%

“…However, if the metal film is capped by B 4 C, the conductive layer is not affected by the native oxide. 28 Hence, the question of native oxide can be resolved by using the double-layer structure with 2.5-nm-thick B 4 C on metal film.…”

Section: Other Items To Be Taken Into Account In Selecting the Conducmentioning

confidence: 99%

“…B 4 C is known as a very stable component and has strong chemical and mechanical resistance. 28 However, the etching selectivity against ML should be confirmed, or the appropriate etching condition should be studied. iii.…”

Section: Other Items To Be Taken Into Account In Selecting the Conducmentioning

confidence: 99%

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Pattern inspection of etched multilayer extreme ultraviolet mask

Iida¹,

Hirano²,

Amano³

et al. 2016

J. Micro/Nanolith. MEMS MOEMS

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Abstract. Patterned mask inspection for an etched multilayer (ML) extreme ultraviolet mask was investigated. In order to optimize the mask structure from the standpoint of a pattern inspection the mask structure not only from the standpoint of a pattern inspection by using a projection electron microscope but also by using a projection electron microscope but also by considering the other fabrication processes using electron beam techniques such as critical dimension metrology and mask repair, we employed a conductive layer between the ML and substrate. By measuring the secondary electron emission coefficients of the candidate materials for the conductive layer, we evaluated the image contrast and the influence of the charging effect. In the cases of 40-pair ML, 16-nm-sized extrusion and intrusion defects were found to be detectable more than 10 sigma in half pitch 44, 40, and 32 nm line-and-space patterns. Reducing 40-pair ML to 20-pair ML degraded the image contrast and the defect detectability. However, by selecting B 4 C as a conductive layer, 16-nm-sized defects and etching residues remained detectable. The 16-nm-sized defects were also detected after the etched part was refilled with Si. A double-layer structure with 2.5-nm-thick B 4 C on metal film used as a conductive layer was found to have sufficient conductivity and also was found to be free from the surface charging effect and influence of native oxide. © 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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Section: Methodsmentioning

confidence: 99%

Section: Other Items To Be Taken Into Account In Selecting the Conducmentioning

confidence: 99%

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Pattern inspection of etched multilayer extreme ultraviolet mask

Iida¹,

Hirano²,

Amano³

et al. 2016

J. Micro/Nanolith. MEMS MOEMS

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“…In order to investigate the impact of capping layer for the MLs on the sensitivity of defect detection, three types of capping layers were used: (1) 2.5-nm-thick Ru, (2) 2.5-nm-thick B 4 C, and (3) 1.25-nm-thick Ru on 1.25-nm-thick B 4 C. The third one is called as B 4 C-buffered Ru capped ML. 13 The MLs contained 40 pairs of 3-nm-thick Mo and 4-nm-thick Si. The thicknesses of the defects were 66 nm, which was the same as that of the absorber layers.…”

Section: Methodsmentioning

confidence: 99%

“…12 Recently, Jang et al reported that B 4 C has a better durability for cleaning and has better chemical, mechanical, and electrical resistance and optical properties than Ru. 13 In this paper, the proposed mask structures, such as B 4 C-capped ML and B 4 C-buffered Ru-capped ML, were investigated from the standpoint of pattern mask inspection and analyzed for their optimal conditions using a PEM technique.…”

Section: Introductionmentioning

confidence: 99%

Impact of B₄C capping layer for extreme ultraviolet mask on the sensitivity of patterned mask inspection using a projection electron microscope

Iida¹,

Hirano²,

Amano³

et al. 2014

J. Micro/Nanolith. MEMS MOEMS

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Abstract. The inspection sensitivity of a patterned extreme ultraviolet mask with B 4 C-capped multilayer (ML) was investigated using a simulated projection electron microscope (PEM) image. Extrusion and intrusion defects with 16-nm size were detected with their intensity of >10 times the standard deviation of the background level on a half-pitch 64-nm line-and-space pattern. The defect detection sensitivity in this case was higher than that of a Ru-capped ML sample and has a potential to meet the requirement for beyond 16-nm node generation from the standpoint of patterned mask inspection using the PEM technique. These results indicate that the B 4 C capping layer, besides its good durability, has an advantage for high sensitivity of patterned mask inspection. The optimal condition of the incident beam energy was found to be 500 and 1,000 eV for the samples of B 4 C-capped ML and B 4 C-buffered Ru-capped ML, respectively. The sensitivity of defect detection was strongly affected by the difference of secondary electron emission coefficients (SEECs) between the absorber layer and capping layer. However, the small incident beam energy was found to be preferable when the SEEC difference was relatively high. © 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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Simulation technique for pattern inspection using a projection electron microscope

Iida¹,

Hirano²,

Amano³

et al. 2015

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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The nature of image formation captured by a projection electron microscope (PEM), and defect detection capability of a PEM inspection system for extreme ultraviolet mask, was investigated by a newly developed Monte Carlo simulator while taking into account an imaging electron optics. The detailed analyses of the electron trajectories clarify the mechanism of the PEM image formation without white band peaks, or undershot dips near the pattern edges. The edge slope of the pattern is affected by the material of the under-layer (capping layer). And its incident beam energy dependence can be derived from the experimentally obtained secondary electron emission coefficients (SEECs) by taking into account the damping effect on the signal intensity at the edge. The incident beam energy dependence on the defect detection capability is in good agreement with the logarithmic plots of the experimentally obtained SEEC difference curves. It was found that the gray level difference (caused by SEEC difference) has much more impact on the defect detectability than the gradient of the edge slope of a pattern has; and thus, the optimal inspection condition can be predicted by measuring the SEEC curves of a sample. These results indicate that high-precision calculation can be carried out using the developed PEM simulator.

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Ruthenium (Ru) peeling and predicting robustness of the capping layer using finite element method (FEM) modeling

Cited by 5 publications

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Pattern inspection of etched multilayer extreme ultraviolet mask

Pattern inspection of etched multilayer extreme ultraviolet mask

Impact of B₄C capping layer for extreme ultraviolet mask on the sensitivity of patterned mask inspection using a projection electron microscope

Simulation technique for pattern inspection using a projection electron microscope

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Ruthenium (Ru) peeling and predicting robustness of the capping layer using finite element method (FEM) modeling

Cited by 5 publications

References 0 publications

Pattern inspection of etched multilayer extreme ultraviolet mask

Pattern inspection of etched multilayer extreme ultraviolet mask

Impact of B4C capping layer for extreme ultraviolet mask on the sensitivity of patterned mask inspection using a projection electron microscope

Simulation technique for pattern inspection using a projection electron microscope

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Product

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Impact of B₄C capping layer for extreme ultraviolet mask on the sensitivity of patterned mask inspection using a projection electron microscope