Quantitative analysis and modeling of line edge roughness in near-field lithography: toward high pattern quality in nanofabrication

Abstract

Quantitative analysis of line edge roughness (LER) is very important for understanding the root causes of LER and thereby improving the pattern quality in near-field lithography (NFL), because LER has become the main limiter of critical dimension (CD) control as the feature size of nanostructures is scaled down. To address this challenge, the photoresist point-spread function of NFL with a contact plasmonic ridge nanoaperture can be employed to account for the physical and chemical effects involved in the LER-generation mechanism. Our theoretical and experimental results show that the sources of LER in NFL mainly come from the aerial image, material chemistry, and process. Importantly, the complicated decay characteristics of surface plasmon waves are demonstrated to be the main optical contributor. Because the evanescent mode of surface plasmon polaritons (SPPs) and quasi-spherical waves (QSWs) decay in the lateral direction, they can induce a small image log-slope and low photoresist contrast, leading to a large LER. We introduce an analytical model and demonstrate the relationship between LER and CD to estimate the pattern quality in NFL. We expect that these results can provide alternative approaches to further improve pattern uniformity and resolution, which can lead to advanced nanopatterning results in NFL.

Enhancement of pattern quality with loss modulation: Applying plasmonic lithography in sub-20 nm technology node and beyond

“…When the plasmonic lithography system produces nanoscale target patterns with an arbitrary shape, the corresponding exposure dose distribution is computed by the convolution between the target pattern and the PSF which is radially symmetric and displays how the beam energy is distributed throughout the PR when a single point is exposed. Therefore, the PSF can be employed to account for all physical and chemical phenomena involved in the patterning process 29 . Significantly, estimation of the PSF with high accuracy and efficiency is crucial in the quantitative analysis of the achievable optical resolution and the near-field OPE in plasmonic lithography.…”

“…, where a is the decay constant at z=0, and b is a dimensionless parameter, the constants a and b depend on the gap size of plasmonic BNA, the dose modulation function (DMF) is defined as DMF=(Dmax-Dmin)/(Dmax+Dmin), where Dmax and Dmin represent the maximum and minimum intensity, respectively 22,28,29 . To record a pattern with a certain depth in the PR layer, the exposure dose is evaluated as Di(g)=Ii(g)tex, where Ii(g) is the intensity at exposure depth z with a ridge gap size of g, tex is the exposure time.…”

“…Plasmonic lithography is a cost-effective and promising technique in manufacturing sub-diffraction-limited nanopatterns for broad applications [18][19][20][21][22][23][24][25][26][27][28][29] . However, as the CD is reduced well below 100 nm and the pattern shapes become more complex and diverse, the near-field optical proximity effect (OPE) will eventually become a limiting factor of pattern quality in the plasmonic lithography since the near-field OPE becomes more serious and it further aggravates the pattern image distortion.…”

Atomically Architected Silicon Pyramid Single-Crystalline Structure Supporting Epitaxial Material Growth and Characteristic Magnetism

“…To accelerate the development and application of 3D materials whose functionality depends on the geometric shape, methodologies that can grow and assemble atomically architected 3D structures with optimal manufacturability are required. Recently, the lithographic methods have been widely used for fabricating 3D structures; however, they are problematic in terms of the atomic perfection of 3D structured samples. , In a lithographic process, dry etching techniques are employed to minimize and shape 3D structures, which unavoidably introduce some damage to and/or deformation of the atomic structures. Because the size of a sample is geometrically constrained to a nanometer length scale, at least in one of the three dimensions, disordered atomic arrangements significantly degrade the physical properties or induce deviation from an ideal value.…”

Application of the Metal Reflector for Redistributing the Focusing Intensity of SPPs

“…Near-field lithography is a technology far beyond the diffraction limit nano-patterning that is applied to exploit diffracted fields, including quasi-spherical waves and surface plasmon polaritons (SPPs) [1][2][3][4][5][6][7][8][9][10]. These waves are radiated by a grating or prism, that can help the incident light confined to a super small scale through the strong near-field coupling via evanescent photons [11].…”