In recent years, significant research efforts have been made to optimize the lithography processes. Liu et al.[1](Nat.Commun, 2024, https://doi.org/10.1038/s41467-024-46743-5)pioneered a new multi-photon lithography t...In recent years, significant research efforts have been made to optimize the lithography processes. Liu et al.[1](Nat.Commun, 2024, https://doi.org/10.1038/s41467-024-46743-5)pioneered a new multi-photon lithography technology in which light field and matter are co-confined, significantly exceeding the limitations of traditional lithography technology. In this news and views, we introduce this work to readers.展开更多
Chitosan(CS)-based nanocomposites have been studied in various fields,requiring a more facile and efficient technique to fabricate nanoparticles with customized structures.In this study,Ag@methacrylamide CS/poly(ethyl...Chitosan(CS)-based nanocomposites have been studied in various fields,requiring a more facile and efficient technique to fabricate nanoparticles with customized structures.In this study,Ag@methacrylamide CS/poly(ethylene glycol)diacrylate(Ag@MP)micropatterns are successfully fabricated by femtosecond laser maskless optical projection lithography(Fs-MOPL)for the first time.The formation mechanism of core-shell nanomaterial is demonstrated by the local surface plasmon resonances and the nucleation and growth theory.Amino and hydroxyl groups greatly affect the number of Ag@MP nanocomposites,which is further verified by replacing MCS with methacrylated bovine serum albumin and hyaluronic acid methacryloyl,respectively.Besides,the performance of the surface-enhanced Raman scattering,cytotoxicity,cell proliferation,and antibacterial was investigated on Ag@MP micropatterns.Therefore,the proposed protocol to prepare hydrogel core-shell micropattern by the home-built Fs-MOPL technique is prospective for potential applications in the biomedical and biotechnological fields,such as biosensors,cell imaging,and antimicrobial.展开更多
Optical imaging systems have greatly extended human visual capabilities,enabling the observation and understanding of diverse phenomena.Imaging technologies span a broad spectrum of wavelengths from x-ray to radio fre...Optical imaging systems have greatly extended human visual capabilities,enabling the observation and understanding of diverse phenomena.Imaging technologies span a broad spectrum of wavelengths from x-ray to radio frequencies and impact research activities and our daily lives.Traditional glass lenses are fabricated through a series of complex processes,while polymers offer versatility and ease of production.However,modern applications often require complex lens assemblies,driving the need for miniaturization and advanced designs with micro-and nanoscale features to surpass the capabilities of traditional fabrication methods.Three-dimensional(3D)printing,or additive manufacturing,presents a solution to these challenges with benefits of rapid prototyping,customized geometries,and efficient production,particularly suited for miniaturized optical imaging devices.Various 3D printing methods have demonstrated advantages over traditional counterparts,yet challenges remain in achieving nanoscale resolutions.Two-photon polymerization lithography(TPL),a nanoscale 3D printing technique,enables the fabrication of intricate structures beyond the optical diffraction limit via the nonlinear process of two-photon absorption within liquid resin.It offers unprecedented abilities,e.g.alignment-free fabrication,micro-and nanoscale capabilities,and rapid prototyping of almost arbitrary complex 3D nanostructures.In this review,we emphasize the importance of the criteria for optical performance evaluation of imaging devices,discuss material properties relevant to TPL,fabrication techniques,and highlight the application of TPL in optical imaging.As the first panoramic review on this topic,it will equip researchers with foundational knowledge and recent advancements of TPL for imaging optics,promoting a deeper understanding of the field.By leveraging on its high-resolution capability,extensive material range,and true 3D processing,alongside advances in materials,fabrication,and design,we envisage disruptive solutions to current challenges and a promising incorporation of TPL in future optical imaging applications.展开更多
Electron beam lithography(EBL)involves the transfer of a pattern onto the surface of a substrate byfirst scanning a thin layer of organicfilm(called resist)on the surface by a tightly focused and precisely controlled el...Electron beam lithography(EBL)involves the transfer of a pattern onto the surface of a substrate byfirst scanning a thin layer of organicfilm(called resist)on the surface by a tightly focused and precisely controlled electron beam(exposure)and then selectively removing the exposed or nonexposed regions of the resist in a solvent(developing).It is widely used for fabrication of integrated cir-cuits,mask manufacturing,photoelectric device processing,and otherfields.The key to drawing circular patterns by EBL is the graphics production and control.In an EBL system,an embedded processor calculates and generates the trajectory coordinates for movement of the electron beam,and outputs the corresponding voltage signal through a digital-to-analog converter(DAC)to control a deflector that changes the position of the electron beam.Through this procedure,it is possible to guarantee the accuracy and real-time con-trol of electron beam scanning deflection.Existing EBL systems mostly use the method of polygonal approximation to expose circles.A circle is divided into several polygons,and the smaller the segmentation,the higher is the precision of the splicing circle.However,owing to the need to generate and scan each polygon separately,an increase in the number of segments will lead to a decrease in the overall lithography speed.In this paper,based on Bresenham’s circle algorithm and exploiting the capabilities of afield-programmable gate array and DAC,an improved real-time circle-producing algorithm is designed for EBL.The algorithm can directly generate cir-cular graphics coordinates such as those for a single circle,solid circle,solid ring,or concentric ring,and is able to effectively realizes deflection and scanning of the electron beam for circular graphics lithography.Compared with the polygonal approximation method,the improved algorithm exhibits improved precision and speed.At the same time,the point generation strategy is optimized to solve the blank pixel and pseudo-pixel problems that arise with Bresenham’s circle algorithm.A complete electron beam deflection system is established to carry out lithography experiments,the results of which show that the error between the exposure results and the preset pat-terns is at the nanometer level,indicating that the improved algorithm meets the requirements for real-time control and high precision of EBL.展开更多
Chiral metamaterials(CMs)composed by artificial chiral resonators have attracted great attentions in the recent decades due to their strong chiroptical resonance and identifiable interaction with chiral materials,faci...Chiral metamaterials(CMs)composed by artificial chiral resonators have attracted great attentions in the recent decades due to their strong chiroptical resonance and identifiable interaction with chiral materials,facilitating practical applications in chiral biosensing,chiral emission,and display technology.However,the complex geometry of CMs improves the fabrication difficulty and hinders their scalable fabrication for practical applications,especially in the visible and ultraviolet wavelengths.One potential strategy is the colloidal lithography that enables parallel fabrication for scalable and various planar structures.Here,we demonstrate a stepwise colloidal lithography technique that uses sequential deposition from multiple CMs and expand their variety and complexity.The geometry and optical chirality of building blocks from single deposition are systematically investigated,and their combination enables a significant extension of the range of chiral patterns by multiple-step depositions.This approach resulted in a myriad of complex designs with different characteristic sizes,compositions,and shapes,which are particularly beneficial for the development of nanophotonic materials.In addition,we designed a flexible chiral device based on PDMS,which exhibits a good CD value and excellent stability even after multiple inward and outward bendings.The excellent compatibility to various substrates makes the planar CMs more flexible in practical applications in microfluidic biosensing.展开更多
In this paper,inspired by lotus leaf surfaces,we fabricated biomimetic multi-scale micro-nano-structures by Two-Step Capillary Force Lithography(TS-CFL)and UV-assisted Capillary Force Lithography(UV-CFL).The experimen...In this paper,inspired by lotus leaf surfaces,we fabricated biomimetic multi-scale micro-nano-structures by Two-Step Capillary Force Lithography(TS-CFL)and UV-assisted Capillary Force Lithography(UV-CFL).The experimental results indicated that TS-CFL was unfitted to fabricate large-area multi-scale micro-nano-structures.Conversely,UV-CFL can fabricate large-area multi-scale micro-nano-structures.We discussed the hydrophobic and anti-icing properties of the biomimetic surfaces fabricated by these two technologies.We found that small structures are significant for improving the hydrophobic anti-icing properties of single-structured or structureless surfaces.We believe that these results can complement the experimental details of both technologies and enable the development of more interesting micro-nano-structures biomimetic surfaces by both technologies in the future.展开更多
Optical proximity correction (OPC) systems require an accurate and fast way to predict how patterns will be transferred to the wafer.Based on Gabor's 'reduction to principal waves',a partially coherent ima...Optical proximity correction (OPC) systems require an accurate and fast way to predict how patterns will be transferred to the wafer.Based on Gabor's 'reduction to principal waves',a partially coherent imaging system can be represented as a superposition of coherent imaging systems,so an accurate and fast sparse aerial image intensity calculation algorithm for lithography simulation is presented based on convolution kernels,which also include simulating the lateral diffusion and some mask processing effects via Gaussian filter.The simplicity of this model leads to substantial computational and analytical benefits.Efficiency of this method is also shown through simulation results.展开更多
A new method for determining proximity parameters α,β ,and η in electron beam lithography is introduced on the assumption that the point exposure spread function is composed of two Gaussians.A single line i...A new method for determining proximity parameters α,β ,and η in electron beam lithography is introduced on the assumption that the point exposure spread function is composed of two Gaussians.A single line is used as test pattern to determine proximity effect parameters and the normalization approach is adopted in experimental data transaction in order to eliminate the need of measuring exposure clearing dose of the resist.Furthermore,the parameters acquired by this method are successfully used for proximity effect correction in electron beam lithography on the same experimental conditions.展开更多
Silicon crystal-facet-dependent nanostructures have been successfully fabricated on a （100）-oriented silicon-oninsulator wafer using electron-beam lithography and the silicon anisotropic wet etching technique. This ...Silicon crystal-facet-dependent nanostructures have been successfully fabricated on a （100）-oriented silicon-oninsulator wafer using electron-beam lithography and the silicon anisotropic wet etching technique. This technique takes advantage of the large difference in etching properties for different crystallographic planes in alkaline solution. The minimum size of the trapezoidal top for those Si nanostructures can be reduced to less than 10nm. Scanning electron microscopy （SEM） and atomic force microscopy （AFM） observations indicate that the etched nanostructures have controllable shapes and smooth surfaces.展开更多
This paper reports a procedure of soft x-ray lithography for the fabrication of an organic crossbar structure. Electron beam lithography is employed to fabricate the mask for soft x-ray lithography, with direct writin...This paper reports a procedure of soft x-ray lithography for the fabrication of an organic crossbar structure. Electron beam lithography is employed to fabricate the mask for soft x-ray lithography, with direct writing technology to the lithograph positive resist and polymethyl methacrylate on the polyimide film. Then Au is electroplated on the polyimide film. Hard contact mode exposure is used in x-ray lithography to transfer the graph from the mask to the wafer. The 256-bits organic memory is achieved with the critical dimension of 250 nm.展开更多
The JEOL JBX-5000LS is a vector type machine.The system hardware features an ion-pumped column,a LaB 6 electron emitter,25kV and 50kV accelerating voltage,and a turbo-pumped sample chamber.The resolution,stability,st...The JEOL JBX-5000LS is a vector type machine.The system hardware features an ion-pumped column,a LaB 6 electron emitter,25kV and 50kV accelerating voltage,and a turbo-pumped sample chamber.The resolution,stability,stitching and overlay of this system are evaluated.The system can write complex patterns at dimensions down to 30nm.The demonstrated overlay accuracy of this system is better than 40nm.展开更多
Cost effective patterning based on scanning probe nanolithography(SPL)has the potential for electronic and optical nano-device manufacturing and other nanotechnological applications.One of the fundamental advantages o...Cost effective patterning based on scanning probe nanolithography(SPL)has the potential for electronic and optical nano-device manufacturing and other nanotechnological applications.One of the fundamental advantages of SPL is its capability for patterning and imaging employing the same probe.This is achieved with self-sensing and self-actuating cantilevers,also known as‘active'cantilevers.Here we used active cantilevers to demonstrate a novel path towards single digit nanoscale patterning by employing a low energy(<100 eV)electron exposure to thin films of molecular resist.By tuning the electron energies to the lithographically relevant chemical resist transformations,the interaction volumes can be highly localized.This method allows for greater control over spatially confined lithography and enhances sensitivity.We found that at low electron energies,the exposure in ambient conditions required approximately 10 electrons per single calixarene molecule to induce a crosslinking event.The sensitivity was 80-times greater than a classical electron beam exposure at 30 keV.By operating the electro-exposure process in ambient conditions a novel lithographic reaction scheme based on a direct ablation of resist material(positive tone)is presented.展开更多
Computational lithography(CL)has become an indispensable technology to improve imaging resolution and fidelity of deep sub-wavelength lithography.The state-of-the-art CL approaches are capable of optimizing pixel-base...Computational lithography(CL)has become an indispensable technology to improve imaging resolution and fidelity of deep sub-wavelength lithography.The state-of-the-art CL approaches are capable of optimizing pixel-based mask patterns to effectively improve the degrees of optimization freedom.However,as the growth of data volume of photomask layouts,computational complexity has become a challenging problem that prohibits the applications of advanced CL algorithms.In the past,a number of innovative methods have been developed to improve the computational efficiency of CL algorithms,such as machine learning and deep learning methods.Based on the brief introduction of optical lithography,this paper reviews some recent advances of fast CL approaches based on deep learning.At the end,this paper briefly discusses some potential developments in future work.展开更多
Traditional soft lithography based PDMS device fabrication requires complex procedures carried out in a clean room. Herein, we report a photolithography-free method that rapidly produces PDMS devices in 30 min. By usi...Traditional soft lithography based PDMS device fabrication requires complex procedures carried out in a clean room. Herein, we report a photolithography-free method that rapidly produces PDMS devices in 30 min. By using a laser cutter to ablate a tape, a male photoresist mold can be obtained within 5 min by a simple heating-step, which offers significant superiority over currently used photolithographybased method. Since it requires minimal energy to cut the tape, our fabrication strategy shows good resolution(~ 100 μm) and high throughput. Furthermore, the micro-mold height can be easily controlled by changing the tape types and layers. As a proof-of-concept, we demonstrated that the fabricated PDMS devices are compatible with biochemical reactions such as quenching reaction of KI to fluorescein and cell culture/staining. Collectively, our strategy shows advantages of low input, simple operation procedure and short fabrication time, therefore we believe this photolithography-free method could serve as a promising way for rapid prototyping of PDMS devices and be widely used in general biochemical laboratories.展开更多
Large-area gratings play a crucial role in various engineering fields.However,traditional interference lithography is limited by the size of optical component apertures,making large-area fabrication a challenging task...Large-area gratings play a crucial role in various engineering fields.However,traditional interference lithography is limited by the size of optical component apertures,making large-area fabrication a challenging task.Here,a method for fabricating laser interference lithography pattern arrays with a global alignment reference strategy is proposed.This approach enables alignment of each area of the laser interference lithography pattern arrays,including phase,period,and tilt angle.Two reference gratings are utilized:one is detached from the substrate,while the other remains fixed to it.To achieve global alignment,the exposure area is adjusted by alternating between moving the beam and the substrate.In our experiment,a 3×3 regions grating array was fabricated,and the−1st-order diffraction wavefront measured by the Fizeau interferometer exhibited good continuity.This technique enables effective and efficient alignment with high accuracy across any region in an interference lithography pattern array on large substrates.It can also serve as a common technique for fabricating various types of periodic structures by rotating the substrate.展开更多
Optical true delay lines(OTDLs)of low propagation losses,small footprints and high tuning speeds and efficiencies are of critical importance for various photonic applications.Here,we report fabrication of electro-opti...Optical true delay lines(OTDLs)of low propagation losses,small footprints and high tuning speeds and efficiencies are of critical importance for various photonic applications.Here,we report fabrication of electro-optically switchable OTDLs on lithium niobate on insulator using photolithography assisted chemo-mechanical etching.Our device consists of several low-loss optical waveguides of different lengths which are consecutively connected by electro-optical switches to generate different amounts of time delay.The fabricated OTLDs show an ultra-low propagation loss of^0.03dB/cm for waveguide lengths well above 100 cm.展开更多
We report a type-I Ga Sb-based laterally coupled distributed-feedback（LC-DFB） laser with shallow-etched gratings operating a continuous wave at room temperature without re-growth process. Second-order Bragg gratings...We report a type-I Ga Sb-based laterally coupled distributed-feedback（LC-DFB） laser with shallow-etched gratings operating a continuous wave at room temperature without re-growth process. Second-order Bragg gratings are fabricated alongside the ridge waveguide by interference lithography. Index-coupled LC-DFB laser with a cavity of 1500 μm achieves single longitudinal mode continuous-wave operation at 20℃ with side mode suppression ratio（SMSR） as high as 24 dB.The maximum single mode continuous-wave output power is about 10 mW at room temperature（uncoated facet）. A low threshold current density of 230 A/cm^2 is achieved with differential quantum efficiency estimated to be 93 mW/A. The laser shows a good wavelength stability against drive current and working temperature.展开更多
We present an all-e-beam lithography （EBL） process for the patterning of photonic crystal waveguides. The whole device structures are exposed in two steps. Holes constituting the photonic crystal lattice and defects...We present an all-e-beam lithography （EBL） process for the patterning of photonic crystal waveguides. The whole device structures are exposed in two steps. Holes constituting the photonic crystal lattice and defects are first exposed with a small exposure step size （less than 10nm）. With the introduction of the additional proximity effect to compensate the original proximity effect, the shape, size, and position of the holes can be well controlled. The second step is the exposure of the access waveguides at a larger step size （about 30nm） to improve the scan speed of the EBL. The influence of write-field stitching error can be alleviated by replacing the original waveguides with tapered waveguides at the joint of adjacent write-fields. It is found experimentally that a higher exposure efficiency is achieved with a larger step size;however,a larger step size requires a higher dose.展开更多
High resolution Fresnel zone plates for nanoscale three-dimensional imaging of materials by both soft and hard x-rays are increasingly needed by the broad applications in nanoscience and nanotechnology.When the outmos...High resolution Fresnel zone plates for nanoscale three-dimensional imaging of materials by both soft and hard x-rays are increasingly needed by the broad applications in nanoscience and nanotechnology.When the outmost zone-width is shrinking down to 50 nm or even below,patterning the zone plates with high aspect ratio by electron beam lithography still remains a challenge because of the proximity effect.The uneven charge distribution in the exposed resist is still frequently observed even after standard proximity effect correction(PEC),because of the large variety in the line width.This work develops a new strategy,nicknamed as local proximity effect correction(LPEC),efficiently modifying the deposited energy over the whole zone plate on the top of proximity effect correction.By this way,50 nm zone plates with the aspect ratio from 4:1 up to 15:1 and the duty cycle close to 0.5 have been fabricated.Their imaging capability in soft(1.3 keV)and hard(9 keV)x-ray,respectively,has been demonstrated in Shanghai Synchrotron Radiation Facility(SSRF)with the resolution of 50 nm.The local proximity effect correction developed in this work should also be generally significant for the generation of zone plates with high resolutions beyond 50 nm.展开更多
The use of an attenuated total reflection-coupling mode of prism coated with metal film to excite the interference of the surface plasmon polaritons （SPPs） was proposed for periodic patterning with a resolution of s...The use of an attenuated total reflection-coupling mode of prism coated with metal film to excite the interference of the surface plasmon polaritons （SPPs） was proposed for periodic patterning with a resolution of subwavelength scale. High intensity of electric field can be obtained because of the coupling between SPPs and evanescence under a resonance condition, which can reduce exposure time and improve contrast. In this paper, several critical parameters for maskless surface plasmon resonant lithography are described, and the preliminary simulation based on a finite difference timedomain technique agrees well with the theoretical analysis, which demonstrates this scheme and provides the theoretical basis for further experiments.展开更多
基金supported by Xishan-Tsinghua University Industry University Research Deep Integration Special Projectby Beijing Natural Science Foundation–Xiaomi Innovation Joint Fund (Grant No. L233009)by National Natural Science Foundation of China under Grant No. 62374099。
文摘In recent years, significant research efforts have been made to optimize the lithography processes. Liu et al.[1](Nat.Commun, 2024, https://doi.org/10.1038/s41467-024-46743-5)pioneered a new multi-photon lithography technology in which light field and matter are co-confined, significantly exceeding the limitations of traditional lithography technology. In this news and views, we introduce this work to readers.
基金the National Natural Science Foundation of China(NSFC,Grant Nos.61975213,61475164,51901234,and 61205194)National Key R&D Program of China(Grant Nos.2017YFB1104300and 2016YFA0200500)+2 种基金International Partnership Program of Chinese Academy of Sciences(GJHZ2021130)Cooperative R&D Projects between Austria,FFG and China,CAS(GJHZ1720)supported by JSPS Bilateral Program Number JPJSBP120217203。
文摘Chitosan(CS)-based nanocomposites have been studied in various fields,requiring a more facile and efficient technique to fabricate nanoparticles with customized structures.In this study,Ag@methacrylamide CS/poly(ethylene glycol)diacrylate(Ag@MP)micropatterns are successfully fabricated by femtosecond laser maskless optical projection lithography(Fs-MOPL)for the first time.The formation mechanism of core-shell nanomaterial is demonstrated by the local surface plasmon resonances and the nucleation and growth theory.Amino and hydroxyl groups greatly affect the number of Ag@MP nanocomposites,which is further verified by replacing MCS with methacrylated bovine serum albumin and hyaluronic acid methacryloyl,respectively.Besides,the performance of the surface-enhanced Raman scattering,cytotoxicity,cell proliferation,and antibacterial was investigated on Ag@MP micropatterns.Therefore,the proposed protocol to prepare hydrogel core-shell micropattern by the home-built Fs-MOPL technique is prospective for potential applications in the biomedical and biotechnological fields,such as biosensors,cell imaging,and antimicrobial.
基金support from the National Research Foundation (NRF) Singapore, under its Competitive Research Programme Award NRF-CRP20-20170004 and NRF Investigatorship Award NRF-NRFI06-20200005MTC Programmatic Grant M21J9b0085, as well as the Lite-On Project RS-INDUS-00090+5 种基金support from Australian Research Council (DE220101085, DP220102152)grants from German Research Foundation (SCHM2655/15-1, SCHM2655/21-1)Lee-Lucas Chair in Physics and funding by the Australian Research Council DP220102152financial support from the National Natural Science Foundation of China (Grant No. 62275078)Natural Science Foundation of Hunan Province of China (Grant No. 2022JJ20020)Shenzhen Science and Technology Program (Grant No. JCYJ20220530160405013)
文摘Optical imaging systems have greatly extended human visual capabilities,enabling the observation and understanding of diverse phenomena.Imaging technologies span a broad spectrum of wavelengths from x-ray to radio frequencies and impact research activities and our daily lives.Traditional glass lenses are fabricated through a series of complex processes,while polymers offer versatility and ease of production.However,modern applications often require complex lens assemblies,driving the need for miniaturization and advanced designs with micro-and nanoscale features to surpass the capabilities of traditional fabrication methods.Three-dimensional(3D)printing,or additive manufacturing,presents a solution to these challenges with benefits of rapid prototyping,customized geometries,and efficient production,particularly suited for miniaturized optical imaging devices.Various 3D printing methods have demonstrated advantages over traditional counterparts,yet challenges remain in achieving nanoscale resolutions.Two-photon polymerization lithography(TPL),a nanoscale 3D printing technique,enables the fabrication of intricate structures beyond the optical diffraction limit via the nonlinear process of two-photon absorption within liquid resin.It offers unprecedented abilities,e.g.alignment-free fabrication,micro-and nanoscale capabilities,and rapid prototyping of almost arbitrary complex 3D nanostructures.In this review,we emphasize the importance of the criteria for optical performance evaluation of imaging devices,discuss material properties relevant to TPL,fabrication techniques,and highlight the application of TPL in optical imaging.As the first panoramic review on this topic,it will equip researchers with foundational knowledge and recent advancements of TPL for imaging optics,promoting a deeper understanding of the field.By leveraging on its high-resolution capability,extensive material range,and true 3D processing,alongside advances in materials,fabrication,and design,we envisage disruptive solutions to current challenges and a promising incorporation of TPL in future optical imaging applications.
基金supported by the Focused Ion Beam/Electron Beam Double Beam Microscopy(Grant No.2021YFF0704702).
文摘Electron beam lithography(EBL)involves the transfer of a pattern onto the surface of a substrate byfirst scanning a thin layer of organicfilm(called resist)on the surface by a tightly focused and precisely controlled electron beam(exposure)and then selectively removing the exposed or nonexposed regions of the resist in a solvent(developing).It is widely used for fabrication of integrated cir-cuits,mask manufacturing,photoelectric device processing,and otherfields.The key to drawing circular patterns by EBL is the graphics production and control.In an EBL system,an embedded processor calculates and generates the trajectory coordinates for movement of the electron beam,and outputs the corresponding voltage signal through a digital-to-analog converter(DAC)to control a deflector that changes the position of the electron beam.Through this procedure,it is possible to guarantee the accuracy and real-time con-trol of electron beam scanning deflection.Existing EBL systems mostly use the method of polygonal approximation to expose circles.A circle is divided into several polygons,and the smaller the segmentation,the higher is the precision of the splicing circle.However,owing to the need to generate and scan each polygon separately,an increase in the number of segments will lead to a decrease in the overall lithography speed.In this paper,based on Bresenham’s circle algorithm and exploiting the capabilities of afield-programmable gate array and DAC,an improved real-time circle-producing algorithm is designed for EBL.The algorithm can directly generate cir-cular graphics coordinates such as those for a single circle,solid circle,solid ring,or concentric ring,and is able to effectively realizes deflection and scanning of the electron beam for circular graphics lithography.Compared with the polygonal approximation method,the improved algorithm exhibits improved precision and speed.At the same time,the point generation strategy is optimized to solve the blank pixel and pseudo-pixel problems that arise with Bresenham’s circle algorithm.A complete electron beam deflection system is established to carry out lithography experiments,the results of which show that the error between the exposure results and the preset pat-terns is at the nanometer level,indicating that the improved algorithm meets the requirements for real-time control and high precision of EBL.
基金This study was financially supported by the International Science and Technology Innovation Cooperation of Sichuan Province(No.21GJHZ0230)the National Natural Science Foundation of China(No.11604227)+1 种基金the International Visiting Program for Excellent Young Scholars of SCU(No.20181504)the Tenure Track program of the University of Twente.
文摘Chiral metamaterials(CMs)composed by artificial chiral resonators have attracted great attentions in the recent decades due to their strong chiroptical resonance and identifiable interaction with chiral materials,facilitating practical applications in chiral biosensing,chiral emission,and display technology.However,the complex geometry of CMs improves the fabrication difficulty and hinders their scalable fabrication for practical applications,especially in the visible and ultraviolet wavelengths.One potential strategy is the colloidal lithography that enables parallel fabrication for scalable and various planar structures.Here,we demonstrate a stepwise colloidal lithography technique that uses sequential deposition from multiple CMs and expand their variety and complexity.The geometry and optical chirality of building blocks from single deposition are systematically investigated,and their combination enables a significant extension of the range of chiral patterns by multiple-step depositions.This approach resulted in a myriad of complex designs with different characteristic sizes,compositions,and shapes,which are particularly beneficial for the development of nanophotonic materials.In addition,we designed a flexible chiral device based on PDMS,which exhibits a good CD value and excellent stability even after multiple inward and outward bendings.The excellent compatibility to various substrates makes the planar CMs more flexible in practical applications in microfluidic biosensing.
基金supported by National Natural Science Foundation of China(Nos.61705096,12274189 and 62075092)Natural Science Foundation of Shandong Province(ZR2021MF121)Yantai City-University Integration Development Project(2021XDRHXMXK26,2021XKZY03).
文摘In this paper,inspired by lotus leaf surfaces,we fabricated biomimetic multi-scale micro-nano-structures by Two-Step Capillary Force Lithography(TS-CFL)and UV-assisted Capillary Force Lithography(UV-CFL).The experimental results indicated that TS-CFL was unfitted to fabricate large-area multi-scale micro-nano-structures.Conversely,UV-CFL can fabricate large-area multi-scale micro-nano-structures.We discussed the hydrophobic and anti-icing properties of the biomimetic surfaces fabricated by these two technologies.We found that small structures are significant for improving the hydrophobic anti-icing properties of single-structured or structureless surfaces.We believe that these results can complement the experimental details of both technologies and enable the development of more interesting micro-nano-structures biomimetic surfaces by both technologies in the future.
文摘Optical proximity correction (OPC) systems require an accurate and fast way to predict how patterns will be transferred to the wafer.Based on Gabor's 'reduction to principal waves',a partially coherent imaging system can be represented as a superposition of coherent imaging systems,so an accurate and fast sparse aerial image intensity calculation algorithm for lithography simulation is presented based on convolution kernels,which also include simulating the lateral diffusion and some mask processing effects via Gaussian filter.The simplicity of this model leads to substantial computational and analytical benefits.Efficiency of this method is also shown through simulation results.
文摘A new method for determining proximity parameters α,β ,and η in electron beam lithography is introduced on the assumption that the point exposure spread function is composed of two Gaussians.A single line is used as test pattern to determine proximity effect parameters and the normalization approach is adopted in experimental data transaction in order to eliminate the need of measuring exposure clearing dose of the resist.Furthermore,the parameters acquired by this method are successfully used for proximity effect correction in electron beam lithography on the same experimental conditions.
文摘Silicon crystal-facet-dependent nanostructures have been successfully fabricated on a （100）-oriented silicon-oninsulator wafer using electron-beam lithography and the silicon anisotropic wet etching technique. This technique takes advantage of the large difference in etching properties for different crystallographic planes in alkaline solution. The minimum size of the trapezoidal top for those Si nanostructures can be reduced to less than 10nm. Scanning electron microscopy （SEM） and atomic force microscopy （AFM） observations indicate that the etched nanostructures have controllable shapes and smooth surfaces.
基金Project supported by the State Key Development Program for Basic Research of China (Grant No. 2006CB806204)National Natural Science Foundation of China (Grant Nos. 60825403,90607022,60676001 and 60676008)Synchrotron Radiation Fund of Innovation Project of Ministry of Education of China (Grant No. 20070156S)
文摘This paper reports a procedure of soft x-ray lithography for the fabrication of an organic crossbar structure. Electron beam lithography is employed to fabricate the mask for soft x-ray lithography, with direct writing technology to the lithograph positive resist and polymethyl methacrylate on the polyimide film. Then Au is electroplated on the polyimide film. Hard contact mode exposure is used in x-ray lithography to transfer the graph from the mask to the wafer. The 256-bits organic memory is achieved with the critical dimension of 250 nm.
文摘The JEOL JBX-5000LS is a vector type machine.The system hardware features an ion-pumped column,a LaB 6 electron emitter,25kV and 50kV accelerating voltage,and a turbo-pumped sample chamber.The resolution,stability,stitching and overlay of this system are evaluated.The system can write complex patterns at dimensions down to 30nm.The demonstrated overlay accuracy of this system is better than 40nm.
文摘Cost effective patterning based on scanning probe nanolithography(SPL)has the potential for electronic and optical nano-device manufacturing and other nanotechnological applications.One of the fundamental advantages of SPL is its capability for patterning and imaging employing the same probe.This is achieved with self-sensing and self-actuating cantilevers,also known as‘active'cantilevers.Here we used active cantilevers to demonstrate a novel path towards single digit nanoscale patterning by employing a low energy(<100 eV)electron exposure to thin films of molecular resist.By tuning the electron energies to the lithographically relevant chemical resist transformations,the interaction volumes can be highly localized.This method allows for greater control over spatially confined lithography and enhances sensitivity.We found that at low electron energies,the exposure in ambient conditions required approximately 10 electrons per single calixarene molecule to induce a crosslinking event.The sensitivity was 80-times greater than a classical electron beam exposure at 30 keV.By operating the electro-exposure process in ambient conditions a novel lithographic reaction scheme based on a direct ablation of resist material(positive tone)is presented.
基金the financial support by the National Natural Science Foundation of China(NSFC)(61675021)the Fundamental Research Funds for the Central Universities(2020CX02002,2018CX01025)。
文摘Computational lithography(CL)has become an indispensable technology to improve imaging resolution and fidelity of deep sub-wavelength lithography.The state-of-the-art CL approaches are capable of optimizing pixel-based mask patterns to effectively improve the degrees of optimization freedom.However,as the growth of data volume of photomask layouts,computational complexity has become a challenging problem that prohibits the applications of advanced CL algorithms.In the past,a number of innovative methods have been developed to improve the computational efficiency of CL algorithms,such as machine learning and deep learning methods.Based on the brief introduction of optical lithography,this paper reviews some recent advances of fast CL approaches based on deep learning.At the end,this paper briefly discusses some potential developments in future work.
基金financial support from the National Natural Science Foundation of China (Nos.21904139,22074152,21735007)Chinese Academy of Sciences (Nos.Y9Y1041001,YJKYYQ20170026)。
文摘Traditional soft lithography based PDMS device fabrication requires complex procedures carried out in a clean room. Herein, we report a photolithography-free method that rapidly produces PDMS devices in 30 min. By using a laser cutter to ablate a tape, a male photoresist mold can be obtained within 5 min by a simple heating-step, which offers significant superiority over currently used photolithographybased method. Since it requires minimal energy to cut the tape, our fabrication strategy shows good resolution(~ 100 μm) and high throughput. Furthermore, the micro-mold height can be easily controlled by changing the tape types and layers. As a proof-of-concept, we demonstrated that the fabricated PDMS devices are compatible with biochemical reactions such as quenching reaction of KI to fluorescein and cell culture/staining. Collectively, our strategy shows advantages of low input, simple operation procedure and short fabrication time, therefore we believe this photolithography-free method could serve as a promising way for rapid prototyping of PDMS devices and be widely used in general biochemical laboratories.
基金supported by the National Natural Science Foundation of China(no.62275142)the Shenzhen Stable Supporting Program(no.WDZC20231124201906001).
文摘Large-area gratings play a crucial role in various engineering fields.However,traditional interference lithography is limited by the size of optical component apertures,making large-area fabrication a challenging task.Here,a method for fabricating laser interference lithography pattern arrays with a global alignment reference strategy is proposed.This approach enables alignment of each area of the laser interference lithography pattern arrays,including phase,period,and tilt angle.Two reference gratings are utilized:one is detached from the substrate,while the other remains fixed to it.To achieve global alignment,the exposure area is adjusted by alternating between moving the beam and the substrate.In our experiment,a 3×3 regions grating array was fabricated,and the−1st-order diffraction wavefront measured by the Fizeau interferometer exhibited good continuity.This technique enables effective and efficient alignment with high accuracy across any region in an interference lithography pattern array on large substrates.It can also serve as a common technique for fabricating various types of periodic structures by rotating the substrate.
基金Supported by the National Key R&D Program of China(Grant No.2019YFA0705000)the National Natural Science Foundation of China(Grant Nos.11734009,61590934,and 11874375)+1 种基金the Strategic Priority Research Program of CAS(Grant No.XDB16030300)the Key Project of the Shanghai Science and Technology Committee(Grant No.17JC1400400).
文摘Optical true delay lines(OTDLs)of low propagation losses,small footprints and high tuning speeds and efficiencies are of critical importance for various photonic applications.Here,we report fabrication of electro-optically switchable OTDLs on lithium niobate on insulator using photolithography assisted chemo-mechanical etching.Our device consists of several low-loss optical waveguides of different lengths which are consecutively connected by electro-optical switches to generate different amounts of time delay.The fabricated OTLDs show an ultra-low propagation loss of^0.03dB/cm for waveguide lengths well above 100 cm.
基金Project supported by the National Key Basic Research Program of China(Grant Nos.2014CB643903 and 2013CB932904)the National Special Funds for the Development of Major Research Equipment and Instruments,China(Grant No.2012YQ140005)+1 种基金the National Natural Science Foundation of China(Grant Nos.61435012,61274013,61306088,and 61290303)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB01010200)
文摘We report a type-I Ga Sb-based laterally coupled distributed-feedback（LC-DFB） laser with shallow-etched gratings operating a continuous wave at room temperature without re-growth process. Second-order Bragg gratings are fabricated alongside the ridge waveguide by interference lithography. Index-coupled LC-DFB laser with a cavity of 1500 μm achieves single longitudinal mode continuous-wave operation at 20℃ with side mode suppression ratio（SMSR） as high as 24 dB.The maximum single mode continuous-wave output power is about 10 mW at room temperature（uncoated facet）. A low threshold current density of 230 A/cm^2 is achieved with differential quantum efficiency estimated to be 93 mW/A. The laser shows a good wavelength stability against drive current and working temperature.
文摘We present an all-e-beam lithography （EBL） process for the patterning of photonic crystal waveguides. The whole device structures are exposed in two steps. Holes constituting the photonic crystal lattice and defects are first exposed with a small exposure step size （less than 10nm）. With the introduction of the additional proximity effect to compensate the original proximity effect, the shape, size, and position of the holes can be well controlled. The second step is the exposure of the access waveguides at a larger step size （about 30nm） to improve the scan speed of the EBL. The influence of write-field stitching error can be alleviated by replacing the original waveguides with tapered waveguides at the joint of adjacent write-fields. It is found experimentally that a higher exposure efficiency is achieved with a larger step size;however,a larger step size requires a higher dose.
基金Project supported by the National Natural Science Foundation of China(Grant No.U1732104)China Postdoctoral Science Foundation(Grant No.2017M611443)Shanghai STCSM2019-11-20 Grant,China(Grant No.19142202700)。
文摘High resolution Fresnel zone plates for nanoscale three-dimensional imaging of materials by both soft and hard x-rays are increasingly needed by the broad applications in nanoscience and nanotechnology.When the outmost zone-width is shrinking down to 50 nm or even below,patterning the zone plates with high aspect ratio by electron beam lithography still remains a challenge because of the proximity effect.The uneven charge distribution in the exposed resist is still frequently observed even after standard proximity effect correction(PEC),because of the large variety in the line width.This work develops a new strategy,nicknamed as local proximity effect correction(LPEC),efficiently modifying the deposited energy over the whole zone plate on the top of proximity effect correction.By this way,50 nm zone plates with the aspect ratio from 4:1 up to 15:1 and the duty cycle close to 0.5 have been fabricated.Their imaging capability in soft(1.3 keV)and hard(9 keV)x-ray,respectively,has been demonstrated in Shanghai Synchrotron Radiation Facility(SSRF)with the resolution of 50 nm.The local proximity effect correction developed in this work should also be generally significant for the generation of zone plates with high resolutions beyond 50 nm.
基金supported by the National Basic Research of China (Grant No 2006CD302900-2)the National Natural Science Foundation of China (Grant No 60676024)the Specialized Research Fund of China for the Doctoral Program of Higher Education (Grant No 20060610006)
文摘The use of an attenuated total reflection-coupling mode of prism coated with metal film to excite the interference of the surface plasmon polaritons （SPPs） was proposed for periodic patterning with a resolution of subwavelength scale. High intensity of electric field can be obtained because of the coupling between SPPs and evanescence under a resonance condition, which can reduce exposure time and improve contrast. In this paper, several critical parameters for maskless surface plasmon resonant lithography are described, and the preliminary simulation based on a finite difference timedomain technique agrees well with the theoretical analysis, which demonstrates this scheme and provides the theoretical basis for further experiments.
