Absorber stack optimization toward EUV lithography mask blank pilot production

Sobel, Frank; Aschke, Lutz; Renno, Markus; Seitz, H.; Becker, Hans; Olschewski, Nathalie; Reichardt, Torsten; Hess, Guenter; Buttgereit, Ute; Knapp, Konrad; Letzkus, Florian; Butschke, Joerg; Koepernik, Corinna

doi:10.1117/12.568787

Cited by 6 publications

(5 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We choose a selected number of values for the radius of the NPs from 2.0 nm to 3.3 nm, and for each case, the total volume fraction of Ni-NPs are kept approximately Wavelength (nm) 15 (d) 12.5 13 13.5 14 14.5 15 Wavelength (nm) the same at 15%. For each value of the radius, at least three randomly-generated structures are simulated, and the averaged results are plotted in Fig.…”

Section: Numerical Studiesmentioning

confidence: 99%

See 1 more Smart Citation

Thin absorber EUV photomask based on mixed Ni and TaN material

et al. 2016

View full text Add to dashboard Cite

Lithographic patterning at the 7 and 5 nm nodes will likely require EUV (λ=13.5 nm) lithography for many of the critical levels. All optical elements in an EUV scanner are reflective which requires the EUV photomask to be illuminated at an angle to its normal. Current scanners have an incidence of 6 degree, but future designs will be >6 degrees for high-NA systems. Non-telecentricity has been shown to cause H-V bias due to shadowing, pattern shift through focus, and image contrast lost due to apodization by the reflective mask coating. A thinner EUV absorber can dramatically reduce these issues. Ni offers better EUV absorption than Ta-based materials, which hold promise as a thinner absorber candidate. Unfortunately, the challenge of etching Ni has prevented its adoption into manufacturing. We propose a new absorber material that infuses Ni nanoparticles into the TaN host medium, allowing for the use of established Ta etching chemistry. A thinner is absorber is created due to the enhanced absorption properties of the Ni-Ta nano-composite material. Finite integral method and effective medium theory-based transfer matrix method have been independently developed to analyze the performance of the nano-composite absorption layer. We show that inserting 15% volume fraction Ni nanoparticles into 40-nm of TaN absorber material can reduce the reflection below 2% over the EUV range. Numerical simulations confirm that the reduced reflectivity is due to the increased absorption of Ni, while scattering only contributes to approximately 0.2% of the reduction in reflectivity.

show abstract

Section: Numerical Studiesmentioning

confidence: 99%

“…Other materials, particularly Nickel (Ni), have been proposed due to their large absorption coefficient in the EUV regime [14,15]. However, a pure-Ni absorption layer is extremely difficult to etch due to Ni's superb stability, and the etching may result in damage to the multi-layer reflector [16].…”

Section: Introductionmentioning

confidence: 99%

Thin absorber EUV photomask based on mixed Ni and TaN material

et al. 2016

View full text Add to dashboard Cite

show abstract

“…In order to meet the reflectivity requirement (< 0.5%) of the SEMI standard, the binary intensity mask (BIM) should have an absorber layer as thick as 70 nm for Ta-based materials [6]. However, a thick absorber structure is not desirable because it induces many practical problems in the mask manufacturing as well as many lithographic performances [7].…”

Section: Introductionmentioning

confidence: 99%

Stochastic resist patterning simulation using attenuated PSM for EUV lithography

Hong

Jeong

Lee

et al. 2013

Extreme Ultraviolet (EUV) Lithography IV

View full text Add to dashboard Cite

In EUV Lithography, mask shadowing effect and photon shot noise effect are the main sources of patterning limit, critical dimension (CD) non-uniformity and low imaging properties. In this paper, the patterning performance of a 6% attenuated phase shift mask (PSM) is valuated, and the results show that this can be used for half-pitch (hp) down to 14 nm with 0.33NA due to the improved stochastic patterning properties. The proposed PSM consists of 26.5 nm of TaN as an absorber layer and 14 nm of Mo as a phase shifter on 2.5 nm thick Ru capped Mo/Si multilayers. This structure has ~6% reflectivity at the absorber stack and 180° phase shift. The improved stochastic resist patterning properties of PSM were compared with those of conventional binary intensity mask (BIM) with a 70 nm-thick TaN absorber for the 14 ~ 22 nm line and space (L/S) 1:1 dense pattern with 0.33NA off-axis illumination conditions with a EUV generic resist model.

show abstract

“…As EUV lithography moves into production for integrated circuits, nickel is being considered as an alternative absorber material. Currently, EUV technology employs a tantalum-based absorber layer mainly due to its high-quality etching selectivity to a ruthenium cap layer [25]. On the other hand, Ta must be 60-70 nm thick to achieve the required reflectively.…”

Section: Introductionmentioning

confidence: 99%

Nanoscale focused electron beam induced etching of nickel using a liquid reactant

et al. 2020

View full text Add to dashboard Cite

Nickel nanostructures have found widespread application as both functional components, e.g. in magnetic systems, and as part of the lithographic pattern transfer process as etch masks, EUV mask absorbers, and imprint templates. Electron-beam induced etching of nickel is highly desirable for the repair and editing of masks and templates with high resolution and without substrate damage. However, there are no known gas-phase reactants that produce volatile nickel products under e-beam irradiation. Here we report the successful local etching of nickel by a focused electron beam in an environmental scanning electron microscope using a liquid reactant, aqueous sulfuric acid. Sulfuric acid did not spontaneously etch nickel under ESEM conditions, but nickel was etched in areas exposed to the electron beam. Etching parameters such as dose, refresh time, and addition of a surfactant were investigated. The extent of the etch increases with dose before terminating at sub-micron feature sizes. The etch resolution improves with the addition of surfactant. This approach enables local nickel patterning with complete film removal but without damaging underlying layers. With further refinement, the process may enable nickel absorber repair and editing and remove a significant obstacle to the use of nickel in EUV lithography. keywords: liquid phase focused electron-beam induced processing, electron beam induced etching, nickel etching, extreme ultraviolet (EUV) lithography mask repair, environmental scanning electron microscopy, two-photon lithography, 3D nanoprinting

show abstract

Absorber stack optimization toward EUV lithography mask blank pilot production

Cited by 6 publications

References 7 publications

Thin absorber EUV photomask based on mixed Ni and TaN material

Thin absorber EUV photomask based on mixed Ni and TaN material

Stochastic resist patterning simulation using attenuated PSM for EUV lithography

Nanoscale focused electron beam induced etching of nickel using a liquid reactant

Contact Info

Product

Resources

About