Pathway to sub-30nm Resolution in EUV Lithography

Thakerlay, James W.; Nassar, Roger A.; Spear-Alfonso, Kathleen; Brainard, Robert L.; Goldfarb, Darı́o L.; Wallow, Thomas I.; Wei, Yayi; Montgomery, Warren; Petrillo, Karen; Wood, Robert L.; Koay, Chief-seng; Mackey, Jeff; Naulleau, Patrick; Pierson, Bill; Solak, Harun H.

doi:10.2494/photopolymer.20.411

Cited by 28 publications

(14 citation statements)

References 12 publications

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“…As the size of semiconductor devices continues to decrease, conventional optical lithography has almost reached its limits as a result of increasing costs and more complex processes. The international technology road map for semiconductors 1 recommended the directed self-assembly (DSA) of block copolymers (BCPs), extreme ultraviolet lithography, [2][3][4] nano-imprint lithography [5][6][7] and mask-less lithography 8 as lithographic methods that could satisfy the requirements of resolution and pattern quality in 16/14 nm complementary metal oxide semiconductor transistor technology. In this context, the DSA technique using BCPs is emerging as a competitive lithographic technique.…”

Section: Introductionmentioning

confidence: 99%

Self-assembling morphologies of symmetrical PS-b-PMMA in different sized confining grooves

et al. 2014

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Section: Introductionmentioning

confidence: 99%

Self-assembling morphologies of symmetrical PS-b-PMMA in different sized confining grooves

et al. 2014

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“…[1][2][3][4] While the theoretical limitations to the RLS trade-off have been well documented, 5,6 this work has all been done at constant film thicknesses. An additional aspect of the RLS trade-off exists that has not been accounted for in these theoretical treatments: as resolution improves, the thickness of resists must concomitantly decrease to prevent line collapse.…”

Section: Introduction 11 Thin-film Ler Problemmentioning

confidence: 99%

LER Limitations of Resist Thin Films

Cardineau

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Fujisawa³

et al. 2012

J. Photopol. Sci. Technol.

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This paper describes fundamental studies of the degradation of LER in EUV resists as a function of film thickness. This research focused on the influence of three variables on this LER film thickness problem:  Substrate interaction (primed silicon vs. organic underlayer)  Changes in optical density (variations in fluorine content)  PAG attachment (bound and unbound)Our experimental approach struck a balance between using resists prepared by commercial resist vendors and using open-source resists with custom-designed polymers to address specific variables listed above. One key feature of this research was our development of a mathematical method for evaluation of the extent of the LER deviation in thin films, called φ LER .Our results showed that the effect of substrate was not significant for two different resists (one commercial and one open source). Additionally, we found that increasing optical density actually made the LER degradation (φ LER ) worse-which was contrary to what was predicted by other researchers. Most significant was our demonstration that PAG attachment plays the most important role in the degradation of LER in thinner resist films; polymer-bound PAGs showed a dramatic 3X improvement in φ LER over a similar blended system.

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“…The intensity of the beam transmitted by the membrane was only about 0.01% of the incident radiation [22], i.e., the plane wave was attenuated by a factor of 10 4 which is required to make the diffracted and transmitted beam intensities similar at the exposure plane. The resulting pattern is recorded on another Cr (23 nm) coated silicon nitride membrane (100 nm thick) using a sensitive chemically-amplified EUV resist (MET 2D) [23] and transferred to the membrane underneath using RIE. SEM images of zone plate patterns obtained by the use of three pinholes of different diameters are shown in Fig.…”

Section: Experimental Procedures and Resultsmentioning

confidence: 99%

Pinhole diffraction holography for fabrication of high-resolution Fresnel Zone Plates

et al. 2014

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Fresnel zone plates (FZPs) play an essential role in high spatial resolution x-ray imaging and analysis of materials in many fields. These diffractive lenses are commonly made by serial writing techniques such as electron beam or focused ion beam lithography. Here we show that pinhole diffraction holography has potential to generate FZP patterns that are free from aberrations and imperfections that may be present in alternative fabrication techniques. In this presented method, FZPs are fabricated by recording interference pattern of a spherical wave generated by diffraction through a pinhole, illuminated with coherent plane wave at extreme ultraviolet (EUV) wavelength. Fundamental and practical issues involved in formation and recording of the interference pattern are considered. It is found that resolution of the produced FZP is directly related to the diameter of the pinhole used and the pinhole size cannot be made arbitrarily small as the transmission of EUV or x-ray light through small pinholes diminishes due to poor refractive index contrast found between materials in these spectral ranges. We also find that the practical restrictions on exposure time due to the light intensity available from current sources directly imposes a limit on the number of zones that can be printed with this method. Therefore a trade-off between the resolution and the FZP diameter exists. Overall, we find that this method can be used to fabricate aberration free FZPs down to a resolution of about 10 nm.

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Pathway to sub-30nm Resolution in EUV Lithography

Cited by 28 publications

References 12 publications

Self-assembling morphologies of symmetrical PS-b-PMMA in different sized confining grooves

Self-assembling morphologies of symmetrical PS-b-PMMA in different sized confining grooves

LER Limitations of Resist Thin Films

Pinhole diffraction holography for fabrication of high-resolution Fresnel Zone Plates

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