Exploring the synergy between EUV lithography and directed self-assembly

Suh, Hyo Seon; Verstraete, Lander; Bel, Julie Van; Bézard, Philippe; Mannaert, G.; Lee, Jae Uk; Wang, Shouhua; Pollentier, Ivan; Rathore, Ashish

doi:10.1117/12.2622565

Cited by 7 publications

(6 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…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.

View full text Add to dashboard Cite

.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.

show abstract

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.

View full text Add to dashboard Cite

show abstract

“…The effective exposure doses were cut by 40% with LWR improvement from 4.2nm to 1.7nm. Recently, Suh et al from IMEC demonstrated [39] a modified EUV/DSA flow, as shown in Fig. 12.…”

Section: The Process and Benefitsmentioning

confidence: 98%

“…Fig. 12 EUV/DSA flow by IMEC [39]. Plasma treatment and resist stripping are included to generate the chemical pattern.…”

Section: The Process and Benefitsmentioning

confidence: 99%

“…Furthermore, Suh et al also proposed an all-track flow [39], which dramatically reduced the number of steps in the process flow by taking advantage of the robustness of the image formed by a negative-tone resist, such as good adhesion to underlayer Mat, PMMA preferential nature, and very thin film as the guide pattern for DSA process, shown in Fig. 13.…”

Section: The Process and Benefitsmentioning

confidence: 99%

See 1 more Smart Citation

Negative-tone resists for EUV lithography

Kim

Her

Wu³

et al. 2023

Advances in Patterning Materials and Processes XL

View full text Add to dashboard Cite

The adoption of extreme ultraviolet lithography (EUVL) has enabled the manufacturing of semiconductor chips with circuit dimensions below 20nm. Photoresists used in the current EUVL are based on the extension of polymeric chemically amplified photoresist system initially introduced three decades ago. While having been the industry's workhorse since the deep UV era, its limitations have begun to emerge too. With requirements for line edge roughness (LER) approaching single nanometer and resolution falling below 15nm, the inherent large scale and inhomogeneity of polymeric systems lead to great technical challenges. Miniaturization of the building blocks of photoresist is desired for further scaling. In the meanwhile, the demand for higher throughput in lithography process due to the restriction of EUV source power requires faster photo-speed as well. In this study, a molecular resist platform is developed with the superior dose-to-size well below 50mJ/cm2. The resist forms negative-tone images which is beneficial for printing pillars and isolated lines utilizing dark-field masks. Pillars in hexagonal arrays with pitch below 38nm are patterned with local CD uniformity (LCDU) below 3nm. Thanks to its negative-tone nature, top loss of the resist film is minimal, which results in higher remaining film to sustain the subsequent etch process. The robust design of the molecular core renders the resist film enhanced etch resistance. Pattern transferring into over 15nm silicon layer was demonstrated using a simple stack. The new resists offer a more straightforward solution to print pillars and similar features without tone-inversion process. The negative-tone resists can be combined with the DSA technology to significantly improve cost of ownership. The processes were successfully implemented for both contact hole and line/space patterns with drastically improved pattern quality. LCDU of 1.4nm was achieved for contact hole pattern at pitch of 34nm in hexagonal array. It could be considered as an alternative to EUV double patterning or high-NA EUV processes.

show abstract

“…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], pre-and post-processing holistic approach [12], photoresist-underlayer matching [8], complementary direct self-assembly [13], and others, are being taken to this purpose. Meanwhile, it should not be overlooked that underlayers (a.k.a.…”

Section: Introductionmentioning

confidence: 99%

Scaling and readiness of underlayers for high-NA EUV lithography

Fallica

Simone

Chen

et al. 2022

International Conference on Extreme Ultraviolet Lithography 2022

View full text Add to dashboard Cite

With the introduction of high-numerical aperture extreme ultraviolet lithography, the thickness of layers in the lithographic stack will scale owing to reduced depth of focus and etch budget. While several studies have explored the impact of thickness scaling on photoresists, the consequence of thinning down underlayers for extreme ultraviolet (EUV) lithography has been scarcely investigated. In this work we assessed the readiness of nine state-of-the-art underlayers, spin-on and dry deposited, scaled in thickness series down to 4 nm nominal (~3 nm actual). Dose-to-size and exposure latitude changed by less than 5 % when thickness of underlayer was decreased. In summary, most of EUV underlayers investigated in this work showed minimal impact on the physical and chemical properties as well as the patterning performance when scaling in view of high numerical aperture extreme ultraviolet lithography.

show abstract

Exploring the synergy between EUV lithography and directed self-assembly

Cited by 7 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

Negative-tone resists for EUV lithography

Scaling and readiness of underlayers for high-NA EUV lithography

Contact Info

Product

Resources

About