3D free forms in c-Si via grayscale lithography and RIE

Khazi, Isman; Muthiah, Uma; Mescheder, Ulrich

doi:10.1016/j.mee.2018.02.006

Cited by 24 publications

(26 citation statements)

References 11 publications

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“…The used PMMA has been shown to be stable enough to allow for replication of daughter molds directly from the PMMA to preserve the pattern fidelity [29]. Considering the used pattern size, we see this as an alternative to pattern transfer [30].…”

Section: Figure 4: (A)mentioning

confidence: 99%

Single-digit 6-nm multilevel patterns by electron beam grayscale lithography

Kirchner

Guzenko

Schift

2019

Advanced Optical Technologies

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We report on the fabrication of very high-resolution discrete four-resist-level grayscale patterns in poly(methyl methacrylate) with just 6-nm step height and down to 32-nm step width using dose-modulated, grayscale electron beam lithography and a low-contrast resist-developer system. This direct pattern writing is important for replication in high-volume manufacturing of diffractive optics. An innovative concept of unexposed auxiliary spacers helped to enhance the discrete character of the multi-level patterns. For pattern step widths between 100 and 32 nm, a transformation toward blazed gratings with increasingly continuous-slope character was obtained. All high-resolution patterns were prepared in a single exposure and development process from an initially about 30-nm thin film. The pattern roughness due to a relatively large polymer molecular weight was reduced using selective thermal annealing with only minimally affecting the global pattern shape by reflow. The results will enable further approaches toward single-digit vertical and prospectively single-digit lateral resolution grayscale patterns.

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Section: Figure 4: (A)mentioning

confidence: 99%

Single-digit 6-nm multilevel patterns by electron beam grayscale lithography

Kirchner

Guzenko

Schift

2019

Advanced Optical Technologies

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“…Furthermore, the masked-based GSL has been reported for fabrication of 3D photoresist structures showing a gradient in their height; however, the requirement for the multiple masks and strict alignment needed to expose layouts makes this approach complicated, expensive and time consuming for the 3D exposures [1,3]. Besides, the use of GSL using direct writing laser (DWL) has been proven to be a promising technique for high throughput microfabrication of 3D microstructures at both micro-and nanoscale dimensions [1,[6][7][8]. The advantage of maskless exposure with the possibility of modulation of the laser exposure intensity (i.e.…”

Section: Introductionmentioning

confidence: 99%

“…by anisotropic DRIE or RIE etching, referred in this case as grayscale technology-GST) or in molding materials (i.e. by molding) [6,9]. Although the…”

Section: Introductionmentioning

confidence: 99%

“…efficacy of using GSL for the microfabrication of simple 3D geometries such as convex and concave micro-lenses, micropyramids etc. have been successfully reported wherein, the modulation of the laser intensity was gradual; thereby, resulting in smooth gradient surface profile of the exposed 3D microstructures [1,6,7]. However, the feasibility of pattern transferring of complex 3D geometries i.e.…”

Section: Introductionmentioning

confidence: 99%

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Untitled

2020

JAMSER

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“…To achieve comparable patterns, high-resolution grayscale lithography along with sophisticated pattern transfer would be required. [18][19][20]21] Of course, different shapes of initial patterns are conceivable but this work concentrates on rectilinear shapes ( Figure S1, Supporting Information) to obtain pyramidal structures with rectilinear base. The respective metal patterns are obtained via lift-off processing of electron beam evaporated thin gold, platinum, or chromium films with and without titanium adhesion layers.…”

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confidence: 99%

Anisotropic Etching of Pyramidal Silica Reliefs with Metal Masks and Hydrofluoric Acid

Kirchner

Neumann

Winkler

et al. 2020

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This work describes the fabrication of anisotropically etched, faceted pyramidal structures in amorphous layers of silicon dioxide or glass. Anisotropic and crystal‐oriented etching of silicon is well known. Anisotropic etching behavior in completely amorphous layers of silicon dioxide in combination with purely isotropic hydrofluoric acid as etchant is an unexpected phenomenon. The work presents practical exploitations of this new process for self‐perfecting pyramidal structures. It can be used for textured silica or glass surfaces. The reason for the observed anisotropy, leading to enhanced lateral etch rates, is the presence of thin metal layers. The lateral etch rate under the metal significantly exceeds the vertical etch rate of the non‐metallized area by a factor of about 6–43 for liquid and 59 for vapor‐based processes. The ratio between lateral and vertical etch rate, thus the sidewall inclination, can be controlled by etchant concentration and selected metal. The described process allows for direct fabrication of shallow angle pyramids, which for example can enhance the coupling efficiency of light emitting diodes or solar cells, can be exploited for producing dedicated silicon dioxide atomic force microscopy tips with a radius in the 50 nm range, or can potentially be used for surface plasmonics.

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3D free forms in c-Si via grayscale lithography and RIE

Cited by 24 publications

References 11 publications

Single-digit 6-nm multilevel patterns by electron beam grayscale lithography

Single-digit 6-nm multilevel patterns by electron beam grayscale lithography

Untitled

Anisotropic Etching of Pyramidal Silica Reliefs with Metal Masks and Hydrofluoric Acid

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