25 nm immersion lithography at 193 nm wavelength

Smith, Bruce W.; Fan, Yongfa; Slocum, Michael A.; Zavyalova, Lena

doi:10.1117/12.602414

Cited by 23 publications

(8 citation statements)

References 4 publications

(4 reference statements)

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“…At this wavelength, the dielectric constants of SiO 2 , Al 2 O 3 , Al and Si are 2.44, 3.74, −4.84+0.50i and −6.94+4.91i, respectively 31 32 . The dielectric constant of common 193 nm PRs is 2.89 33 34 .…”

Section: Resultsmentioning

confidence: 99%

Pushing the resolution of photolithography down to 15nm by surface plasmon interference

Dong

Liu

Kang

et al. 2014

Sci Rep

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A deep ultraviolet plasmonic structure is designed and a surface plasmon interference lithography method using the structure is proposed to generate large-area periodic nanopatterns. By exciting the anti-symmetric coupled surface plasmon polaritons in the structure, ultrahigh resolution periodic patterns can be formed in a photoresist. The resolution of the generated patterns can be tuned by changing the refractive index and thickness of the photoresist. We demonstrate numerically that one-dimensional and two-dimensional patterns with a half-pitch resolution of 14.6 nm can be generated in a 25 nm-thick photoresist by using the structure under 193 nm illumination. Furthermore, the half-pitch resolution of the generated patterns can be down to 13 nm if high refractive index photoresists are used. Our findings open up an avenue to push the half-pitch resolution of photolithography towards 10 nm.

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Section: Resultsmentioning

confidence: 99%

Pushing the resolution of photolithography down to 15nm by surface plasmon interference

Dong

Liu

Kang

et al. 2014

Sci Rep

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“…For these reasons high-index 193 nm immersion lithography was first explored using sapphire prisms for interference imaging, and sapphire for LLEs were then suggested. 9 Some of the significant physical and optical parameters of sapphire are listed in Table 1, along those for LuAG for comparison. …”

Section: Sapphire As High-index Last Lens Elementmentioning

confidence: 99%

Birefringence issues with uniaxial crystals as last lens elements for high-index immersion lithography

et al. 2009

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We discuss the birefringence issues associated with use of crystalline sapphire, with uniaxial crystal structure, as a last lens element for high-index 193 nm immersion lithography. Sapphire is a credible high-index lens material candidate because with appropriate orientation and TE polarization the ordinary ray exhibits the required isotropic optical properties. Also, its material properties may give it higher potential to meet the stringent optical requirements compared to the potential of the principal candidate materials, cubic-symmetry LuAG and ceramic spinel. The TE polarization restriction is required anyway for hyper-NA imaging, due to TM-polarization contrast degradation effects. Further, the high uniaxial-structure birefringence of sapphire may offer the advantage that any residual TM polarization results in a relatively-uniform flare instead of contrast degradation. One issue with this concept is that spatial-dispersion-induced effects should cause some index anisotropy of the ordinary rays, in a way similar to the intrinsic birefringence (IBR) effects in cubic crystals, except that there is no ray splitting. We present the theory of this effect for the trigonal crystal structure of sapphire and discuss its implications for lithography optics. For this material the spatial-dispersion-induced effects are characterized by eight material parameters, of which three contribute to index anisotropy of the ordinary rays. Only one gives rise to azimuthal distortions, and may present challenges for correction. To assess the consequences of using sapphire as a last element, neglecting any IBR effects, we use lithography simulations to characterize the lithographic performance for a 1.7 NA design, and compare to that for LuAG.

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“…The current printing technology, Deep Ultraviolet (DUV) lithography has surpassed the 25 nm technological node by using immersion lithography techniques [1][2][3] to increase the numerical aperture. More recently, Intel has developed novel FinFET design based on multiple exposure techniques to reach the 14 nm node [4].…”

Section: Introductionmentioning

confidence: 99%

Thin absorber EUV photomask based on mixed Ni and TaN material

et al. 2016

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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.

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25 nm immersion lithography at 193 nm wavelength

Cited by 23 publications

References 4 publications

Pushing the resolution of photolithography down to 15nm by surface plasmon interference

Pushing the resolution of photolithography down to 15nm by surface plasmon interference

Birefringence issues with uniaxial crystals as last lens elements for high-index immersion lithography

Thin absorber EUV photomask based on mixed Ni and TaN material

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