Third dimension of proximity effect correction (PEC)

Unal, Nezih; Mahalu, D.; Raslin, Olga; Ritter, Daniel; Sambale, Christoph; Hofmann, Ulrich

doi:10.1016/j.mee.2009.12.002

Cited by 18 publications

(7 citation statements)

References 2 publications

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“…Electron dosing for GEBL was performed according to the resist contrast curve provided by McCoy et al (2018), which is based on a room-temperature development recipe consisting of 2 minutes in a 1:1 mixture of methyl isobutyl ketone (MIBK) and isopropyl alcohol (IPA) followed by a 30-second rinse in IPA and a high-purity nitrogen blow-dry. This contrast curve is shown in Figure 5, where post-development PMMA thickness as measured by spectroscopic ellipsometry is plotted as a function of electron dose, D. These data were processed using the three-dimensional proximity effect correction (3DPEC) algorithm included in the Layout Beamer software package developed by GenISys GmbH 6 (Unal et al 2010) to generate a dose-corrected layout appropriate for achieving exposed staircase steps with h 1 ≈ 0.66h 0 and h 2 ≈ 0.33h 0 , where h 0 ≈ 130 nm is the spin-coat thickness. Electron exposure for GEBL was carried out using an 8 nA beam current and a 400 µm aperture with a beam step size and a writing grid resolution of 10 nm, which is comparable to the beam spot size realized by the EBPG5200 under these conditions.…”

Section: Thermally Activated Selective Topography Equilibration (Taste)mentioning

confidence: 99%

Extreme Ultraviolet and Soft X-Ray Diffraction Efficiency of a Blazed Reflection Grating Fabricated by Thermally Activated Selective Topography Equilibration

McCoy

McEntaffer²,

Miles

2020

ApJ

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Future observatories utilizing reflection grating spectrometers for extreme ultraviolet (EUV) and soft x-ray (SXR) spectroscopy require high-fidelity gratings with both blazed groove facets and custom groove layouts that are often fanned or feature a slight curvature. While fabrication procedures centering on wet anisotropic etching in mono-crystalline silicon produce highly-efficient blazed gratings, the precision of a non-parallel groove layout is limited by the cubic structure of the silicon crystal. This motivates the pursuit of alternative techniques to grating manufacture, namely thermally activated selective topography equilibration (TASTE), which uses grayscale electron-beam lithography to pattern multi-leveled structures in resist followed by an optimized polymer thermal reflow to smooth the 3D patterns into continuous surface relief profiles. Using TASTE, a mold for a reflection grating with a periodicity of 400 nm and grooves resembling an asymmetric sawtooth was patterned in 130 nmthick poly(methyl methacrylate) resist on a silicon substrate over a 50 mm by 7.5 mm area. This structure was coated with 15 nm of gold by electron-beam physical vapor deposition using titanium as an adhesion layer and then tested for EUV and SXR diffraction efficiency at beamline 6.3.2 of the Advanced Light Source synchrotron facility. Results demonstrate a quasi-blaze response characteristic of a 27 • blaze angle with groove facets smooth to 1.5 nm RMS. Absolute peak order efficiency ranges from 75% to 25% while total relative efficiency measures 90% across the measured bandpass of 15.5 nm > λ > 1.55 nm.

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Section: Thermally Activated Selective Topography Equilibration (Taste)mentioning

confidence: 99%

Extreme Ultraviolet and Soft X-Ray Diffraction Efficiency of a Blazed Reflection Grating Fabricated by Thermally Activated Selective Topography Equilibration

McCoy

McEntaffer²,

Miles

2020

ApJ

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“…Although the zero of energy is not defined by the authors, 23 it is assumed here that it is the bottom of the valence band. Due to the lack of known bond-breaking cross sections, a common approach is to store the energy lost in an inelastic event or a trapping event, in the volume element (voxel) of resist where the event occurred, 7,8,24 provided that more energy than a threshold value, assumed here as 4.9 eV, is lost. The number of broken bonds is then assumed to be proportional to the deposited energy per voxel, and the distribution of energy deposited in the resist is associated with the PSF.…”

Section: Monte Carlo Simulatormentioning

confidence: 99%

“…In contrast to other applications 24 where 3D PEC is required, we here address how to optimize the exposure of a pattern on a tilted substrate. First, a test pattern was designed, suitable to clearly show the difference when an asymmetric PSF in the proximity effect correction is used instead of the usual symmetrical one.…”

Section: Proximity Effect Corrected Patterning Of Tilted Surfacesmentioning

confidence: 99%

Electron beam lithography on curved or tilted surfaces: Simulations and experiments

Arat

Zonnevylle²,

Ketelaars³

et al. 2019

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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There is a growing interest for patterning on curved or tilted surfaces using electron beam lithography. Computational proximity correction techniques are well established for flat surfaces and perpendicular exposure, but for curved and tilted surfaces adjustments are needed as the dose distribution is no longer cylindrically symmetric with respect to the surface normal. A graphical processing unitaccelerated 3D Monte Carlo simulation, based on first-principle scattering models, is used to simulate the asymmetric dose distribution. Based on that, an approximate adjustment is made to an existing high-performance proximity effect correction (PEC) algorithm aimed at the correct exposure of a pattern of nanowires on a 17°tilted surface. It was experimentally verified that using the adjusted PEC indeed leads to a more uniform exposure on tilted surfaces.

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“…This mapping is important for grayscale electron beam lithography. In this case, the generated file can be used in conjunction with a resist contrast curve to print three dimensional structures [104].…”

Section: Grayscale Image To Gdsmentioning

confidence: 99%