Outlook for high-NA EUV patterning: a holistic patterning approach to address upcoming challenges

Raley, Angélique; Huli, Lior; Grzeskowiak, Steven; Lutker-Lee, Katie; Krawicz, Alexandra; Feurprier, Yannick; Liu, Eric; Kato, Kanzo; Nafus, Kathleen; Dauendorffer, Arnaud; Bae, Na-Young; LaRose, Josh; Metz, Andrew J.; Hetzer, Dave; Honda, Masashi; Nishizuka, Tetsuya; Ko, Akiteru; Okada, Soichiro; Ido, Yasuyuki; Onitsuka, Tomoya; Kawakami, Shinichiro; Fujimoto, Seiji; Shimura, Satoru; Dinh, Cong Que; Murata, Makoto; Biolsi, Peter; Mochiki, Hiromasa; Nagahara, Seiji

doi:10.1117/12.2613063

Cited by 18 publications

(20 citation statements)

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“…Consequently, great effort is being put into investigating and predicting thin photoresist films performance ahead of high-NA EUV. A variety of new approaches such as etch-litho synergy, 9 preprocessing and postprocessing holistic approach, 12 photoresist-underlayer matching, 8 complementary direct self-assembly, 13 and others, are being taken to this purpose.…”

Section: Introductionmentioning

confidence: 99%

Scaling and readiness of underlayers for high-numerical aperture extreme ultraviolet lithography

Fallica

Simone

Chen

et al. 2022

J. Micro/Nanopattern. Mats. Metro.

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.With the introduction of high-numerical aperture (NA) extreme ultraviolet (EUV) lithography, the thickness of layers in the lithographic stack will scale owing to reduced depth of focus and etch budget. The consequence of thinning down underlayers for EUV lithography has been scarcely investigated. In here, we assessed the readiness of nine state-of-the-art underlayers, spin-on and dry deposited, in thickness series down to 4 nm nominal. Preliminarily, the coating quality of these underlayers was evaluated. Thickness uniformity across 300 mm wafer ranged from about ±0.5 nm to < ± 0.05 nm depending on the coating technique employed. Surface roughness of the underlayers varied from as much as 0.63 nm to as low as 0.062 nm but was not impacted by thickness scaling. Film density and total surface energy varied by <10 % with thickness. EUV lithography of dense lines/spaces arrays of pitch 28 nm was carried out using a positive tone chemically amplified photoresist. Dose-to-size and exposure latitude changed by < ± 5 % when thickness of underlayer was decreased. Failure free process was at most 1 nm smaller for thinner underlayer than it was for the thinnest version of each type. The unbiased linewidth roughness increased consistently but limitedly (<5 % ) when thinner underlayers were used, mainly due to a reduction in the correlation length. By calculating the power spectral density of the blanket underlayer we can pinpoint this effect to a reduction of correlation length of the underlayer own surface roughness. Finally, Z-factor calculations demonstrated that overall photoresist performance depended more significantly on the specific underlayer type (±12.6 % ) than it did on underlayer thickness (±8 % ). All these results indicate that most of underlayers investigated had limited impact on the properties as well as the patterning performance when scaling in view of high NA EUV.

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Section: Introductionmentioning

confidence: 99%

Scaling and readiness of underlayers for high-numerical aperture extreme ultraviolet lithography

Fallica

Simone

Chen

et al. 2022

J. Micro/Nanopattern. Mats. Metro.

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“…In our previous literature, a development method named ESPERT TM has been introduced to improve the performance of MOR for 0.33 NA EUV lithography [9,10]. It has been proven to be able to break the dose-roughness trade-off and largely reduce the defects from pattern collapse.…”

Section: New Wet Development Methodsmentioning

confidence: 99%

Advanced development methods for high-NA EUV lithography

Dinh

Nagahara

Kuwahara

et al. 2023

Advances in Patterning Materials and Processes XL

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One of the key steps in the pattern formation chain of (extreme ultraviolet) EUV lithography is the development process to resolve the resist pattern after EUV exposure. A simple traditional development process might not be sufficient to achieve the requirements of an ultra-high-resolution feature with low defect levels in high numerical aperture (NA) EUV lithography. In our previous literature, a new development method named ESPERTTM (Enhanced Sensitivity develoPER TechnologyTM) has been introduced to improve the performance of metal oxide resists (MOR) for 0.33 NA EUV lithography by breaking the dose-roughness trade-off. In this work, this development technique was optimised for high-NA lithography to not only keep the advantages of previous ESPERTTM version, but also reduce the defect levels at a higher EUV sensitivity. This is made possible thanks to the capability of the new version of ESPERTTM that can easily remove the residue (undeveloped resist) at low exposure dose area to enhance the developing contrast. Using 0.33 NA EUV scanners at imec on 16-nm half-pitch (HP) line/space (L/S) patterns, with the new development method, EUV dose-to-size (DtS) was reduced roughly 16%, and total after-development-inspection (ADI) defects was reduced by a factor of approximately 7, simultaneously. In another condition, DtS was reduced from 44.2 to 28.4 mJ/cm² (an improvement of 36%), while the number of after-etch-inspection (AEI) single-bridge defects was reduced by half, simultaneously. Using the 0.5 NA exposure tool at Lawrence Berkeley National Laboratory with this new development method, the exposure sensitivity and line-width-roughness (LWR) were both improved by 30% and 21%, respectively. An 8-nm-HP L/S pattern was also successfully printed by this high NA tool. Using a 150 kV electron-beam (EB) lithography system, a 12-nm-HP of pillars was successfully printed on a 22-nm-thick MOR resist with ESPERTTM. With all the advantages of having a high exposure sensitivity, a low defectivity, and an ultra-high-resolution capability, this new development method is expected to be a solution for high-NA EUV lithography.

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“…From two preliminary studies, it was found that PEB condition and solubility of developer solution were the keys of RLS control. Here, new technology, ESPERT TM is suggested [1,2] . ESPERT TM was devised that which was controlled pattern profile with solubility control in developer step.…”

Section: Sensitivity and Resolution Improvementmentioning

confidence: 99%

Establishment of new process technology for EUV lithography

Kuwahara

Kawakami

Kato

et al. 2023

Advances in Patterning Materials and Processes XL

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Resolution, line edge roughness (LER) and sensitivity (RLS) and defectivity are the well-known critical issues of extreme ultraviolet (EUV) lithography. To break the RLS triangle, metal oxide resist (MOR) is a promising candidate. However, further improvement of MOR process is required for high volume manufacturing to maintain low defectivity. In this paper, conventional and new processes for MOR pitch 32 nm line and space (L/S) and 36 nm pillar patterns was investigated. This new process was able to perform good sensitivity without degrading roughness. In addition, further optimization for underlayer and developer process could mitigate pattern collapses. MOR treatment was evaluated as another technique for roughness improvement. At last, bottom scum defect would be reduced by new process.

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Outlook for high-NA EUV patterning: a holistic patterning approach to address upcoming challenges

Cited by 18 publications

References 0 publications

Scaling and readiness of underlayers for high-numerical aperture extreme ultraviolet lithography

Scaling and readiness of underlayers for high-numerical aperture extreme ultraviolet lithography

Advanced development methods for high-NA EUV lithography

Establishment of new process technology for EUV lithography

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