Tilted metasurface nanostructures,with excellent physical properties and enormous application potential,pose an urgent need for manufacturing methods.Here,electric-field-driven generative-nanoimprinting technique is p...Tilted metasurface nanostructures,with excellent physical properties and enormous application potential,pose an urgent need for manufacturing methods.Here,electric-field-driven generative-nanoimprinting technique is proposed.The electric field applied between the template and the substrate drives the contact,tilting,filling,and holding processes.By accurately controlling the introduced included angle between the flexible template and the substrate,tilted nanostructures with a controllable angle are imprinted onto the substrate,although they are vertical on the template.By flexibly adjusting the electric field intensity and the included angle,large-area uniform-tilted,gradient-tilted,and high-angle-tilted nanostructures are fabricated.In contrast to traditional replication,the morphology of the nanoimprinting structure is extended to customized control.This work provides a cost-effective,efficient,and versatile technology for the fabrication of various large-area tilted metasurface structures.As an illustration,a tilted nanograting with a high coupling efficiency is fabricated and integrated into augmented reality displays,demonstrating superior imaging quality.展开更多
2025 marks the 30th anniversary of nanoimprint lithography(NIL).Since its inception in 1995,and through global efforts over the past three decades,nanoimprint has emerged as the primary alternative to extreme ultravio...2025 marks the 30th anniversary of nanoimprint lithography(NIL).Since its inception in 1995,and through global efforts over the past three decades,nanoimprint has emerged as the primary alternative to extreme ultraviolet(EUV)lithography for deep-nanoscale silicon(Si)electronics.Numerous semiconductor companies have recognized NIL's manufacturing quality and are actively being evaluated for the production of the most advanced semiconductor devices.Nanoimprinting's potential extends beyond silicon chip fabrication and wafer-scale applica-tions.With its high throughput and 3D patterning capabilities,NIL is becoming a key technology for fabricating emerging devices,such as flat optics and augmented reality glasses.This review summarizes the key developments and applications of nanoimprint lithography,with a particular focus on the latest industry advancements in nano-Si device manufacturing and nanophotonics applications.展开更多
Nanoimprint lithography(NIL) is an emerging micro/nano-patterning technique,which is a high-resolution,high-throughput and yet simple fabrication process.According to International Technology Roadmap for Semiconductor...Nanoimprint lithography(NIL) is an emerging micro/nano-patterning technique,which is a high-resolution,high-throughput and yet simple fabrication process.According to International Technology Roadmap for Semiconductor(ITRS),NIL has emerged as the next generation lithography candidate for the22 nm and 16 nm technological nodes.In this paper,we present an overview of nanoimprint lithography.The classfication,research focus,critical issues,and the future of nanoimprint lithography are intensively elaborated.A pattern as small as 2.4 nm has been demonstrated.Full-wafer nanoimprint lithography has been completed on a 12-inch wafer.Recently,12.5 nm pattern resolution through soft molecular scale nanoimprint lithography has been achieved by EV Group,a leading nanoimprint lithography technology supplier.展开更多
The development of polymeric optical materials with a higher refractive index,transparency in the visible spectrum region and easier processability is increasingly desirable for advanced optical applications such as m...The development of polymeric optical materials with a higher refractive index,transparency in the visible spectrum region and easier processability is increasingly desirable for advanced optical applications such as microlenses,image sensors,and organic light-emitting diodes.Most acrylates have a low refractive index(around 1.50)which does not meet the high perfo rmance requirements of advanced optical materials.In this research,three novel acrylates were synthesized via a facile one-step approach and used to fabricate optical transparent polymers.All of the polymers reveal good optical properties including high transparency(≥90%)in the visible spectrum region and high refractive index values(1.6363)at 550 nm.Moreover,nanostructures of these acrylate polymers with various feature sizes including nanogratings and photonic crystals were successfully fabricated using nanoimprint lithography.These results indicate that these acrylates can be used in a wide range of optical and optoelectronic devices where nanopatterned films with high refractive index and transparency are required.展开更多
The effects of a twin boundary（TB） on the mechanical properties of two types of bicrystal Al thin films during the nanoimprint process are investigated by using molecular dynamics simulations.The results indicate th...The effects of a twin boundary（TB） on the mechanical properties of two types of bicrystal Al thin films during the nanoimprint process are investigated by using molecular dynamics simulations.The results indicate that for the TB direction parallel to the imprinting direction,the yield stress reaches the maximum for the initial dislocation nucleation when the mould directly imprints to the TB,and the yield stress first decreases with the increase of the marker interval and then increases.However,for the TB direction perpendicular to the imprinting direction,the effect of the TB location to the imprinting forces is very small,and the yield stress is greater than that with the TB direction parallel to the imprinting direction.The results also demonstrate that the direction of the slip dislocations and the deformation of the thin film caused by spring-back are different due to various positions and directions of the TB.展开更多
The low-dimensional,highly anisotropic geometries,and superior mechanical properties of one-dimensional(1D) nanomaterials allow the exquisite strain engineering with a broad tunability inaccessible to bulk or thin-fil...The low-dimensional,highly anisotropic geometries,and superior mechanical properties of one-dimensional(1D) nanomaterials allow the exquisite strain engineering with a broad tunability inaccessible to bulk or thin-film materials.Such capability enables unprecedented possibilities for probing intriguing physics and materials science in the 1-D limit.Among the techniques for introducing controlled strains in 1D materials,nanoimprinting with embossed substrates attracts increased attention due to its capability to parallelly form nanomaterials into wrinkled structures with controlled periodicities,amplitudes,orientations at large scale with nanoscale resolutions.Here,we systematically investigated the strain-engineered anisotropic optical properties in Te nanowires through introducing a controlled strain field using a resist-free thermally assisted nanoimprinting process.The magnitude of induced strains can be tuned by adjusting the imprinting pressure,the nanowire diameter,and the patterns on the substrates.The observed Raman spectra from the chiral-chain lattice of 1D Te reveal the strong lattice vibration response under the strain.Our results suggest the potential of 1D Te as a promising candidate for flexible electronics,deformable optoelectronics,and wearable sensors.The experimental platform can also enable the exquisite mechanical control in other nanomaterials using substrate-induced,on-demand,and controlled strains.展开更多
Nanoimprint lithography （NIL） is recognized as one of the most promising candidates for the next generation lithography （NGL） to obtain sub-100 nm patterns because of its simplicity, high-throughput and low-cost. ...Nanoimprint lithography （NIL） is recognized as one of the most promising candidates for the next generation lithography （NGL） to obtain sub-100 nm patterns because of its simplicity, high-throughput and low-cost. While substantial effort has been expending on NIL for producing smaller and smaller feature sizes, considerably less effort has been devoted to the equally important issue—alignment between template and substrate. A homemade prototype nanoimprint lithography tool with a high precision automatic alignment system based on Moiré signals is presented. Coarse and fine pitch gratings are adopted to produce Moiré signals to control macro and micro actuators and enable the substrate to move towards the desired position automatically. Linear motors with 300 mm travel range and 1 μm step resolution are used as macro actuators, and piezoelectric translators with 50 μm travel range and 1 nm step resolution are used as micro actuators. In addition, the prototype provides one translation （z displacement） and two tilting motion（α and β ） to automatically bring uniform intact contact between the template and substrate surfaces by using a flexure stage. As a result, 10 μm coarse alignment accuracy and 20 nm fine alignment accuracy can be achieved. Finally, some results of nanostructures and micro devices such as nanoscale trenches and holes, gratings and microlens array fabricated using the prototype tool are presented, and hot embossing lithography, one typical NIL technology, are depicted by taking nanoscale gratings fabrication as an example.展开更多
Surface nanopatterning of semiconductor optoelectronic devices is a powerful way to improve their quality and performance.However,photoelectric devices’inherent stress sensitivity and inevitable warpage pose a huge c...Surface nanopatterning of semiconductor optoelectronic devices is a powerful way to improve their quality and performance.However,photoelectric devices’inherent stress sensitivity and inevitable warpage pose a huge challenge on fabricating nanostructures large-scale.Electric-driven flexible-roller nanoimprint lithography for nanopatterning the optoelectronic wafer is proposed in this study.The flexible nanoimprint template twining around a roller is continuously released and recovered,controlled by the roller’s simple motion.The electric field applied to the template and substrate provides the driving force.The contact line of the template and the substrate gradually moves with the roller to enable scanning and adapting to the entire warped substrate,under the electric field.In addition,the driving force generated from electric field is applied to the surface of substrate,so that the substrate is free from external pressure.Furthermore,liquid resist completely fills in microcavities on the template by powerful electric field force,to ensure the fidelity of the nanostructures.The proposed nanoimprint technology is validated on the prototype.Finally,nano-grating structures are fabricated on a gallium nitride light-emitting diode chip adopting the solution,achieving polarization of the light source.展开更多
Dislocation dynamics simulations are performed to investigate the effect of template shape on the nanoimprinting of metal layers. To this end, metal thin films are imprinted by a rigid template made of an array of equ...Dislocation dynamics simulations are performed to investigate the effect of template shape on the nanoimprinting of metal layers. To this end, metal thin films are imprinted by a rigid template made of an array of equispaced indenters of various shapes, i.e., rectangular, wedge, and circular. The geometry of the indenters is chosen such that the contact area is approximately the same at the final imprinting depth. Results show that, for all template shapes, the final patterns strongly depend on the dislocation activity, and that each imprint differs from the neighboring ones. Large material pile ups appear between the imprints, such that polishing of the metal layer is suggested for application of the patterns in electronics. Rectangular indenters require the lowest imprinting force and achieve the deepest retained imprints.展开更多
To tackle the demoulding and conglutinating problem with the resist and hard mold in the nanoimprint lithography process, a soft mould can be used to demould and reduce the macro or mi- cro mismatch between mould bott...To tackle the demoulding and conglutinating problem with the resist and hard mold in the nanoimprint lithography process, a soft mould can be used to demould and reduce the macro or mi- cro mismatch between mould bottom surface and wafer top surface. In nanoimprint lithography process, a mathematical equation is formulated to demonstrate the relation between the residual re- sist thickness and the pressing force during pressing the mould toward the resist-coated wafer. Based on these analytical studies, a new imprint process, which includes a pre-cure release of the pressing force, was proposed for the high-conformity transfer of nano-patterns from the mould to the wafer. The results of a series of imprint experiments showed that the proposed loading process could meet the requirements for the imprint of different patterns and feature sizes while maintaining a uniform residual resist and non-distorted transfer of nano-patterns from the mould to the resist- coated wafer.展开更多
Soft lithography is a low-cost and convenient method for the forming and manufacturing of micro/ nanostructures compared to the traditional optical lithography. In soft lithography, poly（dimethylsiloxane） （PDMS） s...Soft lithography is a low-cost and convenient method for the forming and manufacturing of micro/ nanostructures compared to the traditional optical lithography. In soft lithography, poly（dimethylsiloxane） （PDMS） stamps with relief structures have been widely used to transfer patterns. The traditional fabrication approach of PDMS stamps is time-consuming since the master has been occupied during the curing process. By adding and repeating fast nanoimprint step, many intermediate polymeric molds can be produced from the master and these molds can then be employed to replicate more PDMS stamps while the time used is close to that of the common way. We demonstrated this idea by three masters which were made by the DEM （Deepetching, Electroforming and Microreplicating） and FIB （Focused Ion Beam） techniques. The photos show that the patterns on the PMDS stamps successfully duplicated patterns on the origin masters.展开更多
L10-FePt-type bit-patterned media has provided a promising alternative for ultrahigh-density magnetic recording systems in the current digital era,but rapid fabrication of magnetic patterns with hyperfine bit islands ...L10-FePt-type bit-patterned media has provided a promising alternative for ultrahigh-density magnetic recording systems in the current digital era,but rapid fabrication of magnetic patterns with hyperfine bit islands is still challenging,especially with the target for miniaturization and scalable production simultaneously.Herein,Fe,Pt-containing block copolymers were utilized as single-source precursors for solution-processable patterning and subsequent generation of the demanding magnetic FePt dots by in situ pyrolysis.High-throughput nanoimprint lithography was initially employed to fabricate the predefined bit cells precisely,and then the intrinsic self-assembly of phase-separated block copolymers further drove the formation of accurate bit islands.Benefiting from the synergistic effect of top-down lithographic approach and bottom-up self-assembly,the customizable patterns could be achieved for large-scale mass production in targeted areas,but high-density isolated dots could also be accurately aligned along the patterned features after subsequent self-assembly.This reliable strategy would provide a good avenue to precisely construct ultrahigh-density magnetic data storage devices.展开更多
This article discusses the transition of a form of nanoimprint lithography technology,known as Jet and Flash Imprint Lithography(J-FIL),from research to a commercial fabrication infrastructure for leading-edge semicon...This article discusses the transition of a form of nanoimprint lithography technology,known as Jet and Flash Imprint Lithography(J-FIL),from research to a commercial fabrication infrastructure for leading-edge semiconductor integrated circuits(ICs).Leadingedge semiconductor lithography has some of the most aggressive technology requirements,and has been a key driver in the 50-year history of semiconductor scaling.Introducing a new,disruptive capability into this arena is therefore a case study in a“highrisk-high-reward”opportunity.This article first discusses relevant literature in nanopatterning including advanced lithography options that have been explored by the IC fabrication industry,novel research ideas being explored,and literature in nanoimprint lithography.The article then focuses on the J-FIL process,and the interdisciplinary nature of risk,involving nanoscale precision systems,mechanics,materials,material delivery systems,contamination control,and process engineering.Next,the article discusses the strategic decisions that were made in the early phases of the project including:(i)choosing a step and repeat process approach;(ii)identifying the first target IC market for J-FIL;(iii)defining the product scope and the appropriate collaborations to share the risk-reward landscape;and(iv)properly leveraging existing infrastructure,including minimizing disruption to the widely accepted practices in photolithography.Finally,the paper discusses the commercial J-FIL stepper system and associated infrastructure,and the resulting advances in the key lithographic process metrics such as critical dimension control,overlay,throughput,process defects,and electrical yield over the past 5 years.This article concludes with the current state of the art in J-FIL technology for IC fabrication,including description of the high volume manufacturing stepper tools created for advanced memory manufacturing.展开更多
In this paper,the replication process of large area nanoimprint stamp with small critical dimension(CD) loss was investigated,using the thin residual layer nanoimprint lithography(NIL) technology.The residual layer th...In this paper,the replication process of large area nanoimprint stamp with small critical dimension(CD) loss was investigated,using the thin residual layer nanoimprint lithography(NIL) technology.The residual layer thickness was optimized by changing the spin-coated resist thickness.The dependences of the residual layer etching rate on gas flow,chamber pressure,and RF power were investigated,and the optimized process conditions were established.By means of the thin residual layer NIL technique and optimized residual layer etching process,large area stamp with small CD loss and multi-orientation patterns was successfully replicated on 2-inch SiO2/Si wafer.The CD loss was controlled within 5 nm.The replicated stamp showed high performance in the patterning with thermal NIL.The replication process reported in this work could also be used to fabricate large area nanostructures with small CD loss.展开更多
Flexible electronics have received considerable attention in academies and industries for their promising applications in enormous fields, such as flexible displays, wearable sensors, artificial skins, and flexible en...Flexible electronics have received considerable attention in academies and industries for their promising applications in enormous fields, such as flexible displays, wearable sensors, artificial skins, and flexible energy devices. Challenges remain in developing a flexible and scalable manufacturing method to facilitate the fabrication of multi-functional structures in a flexible electronic system. Nanoimprint lithography is a high resolution and low-cost approach to fabricate nanostructures over a large area. This paper reviews recent progress of nanoimprint lithography and its applications in flexible electronics. The basic principles, classification, research focus, and critical issues of nanoimprint lithography are elaborated. Then, the advantages of nanoimprint lithography are demonstrated in several typical applications related to flexible electronics, including conductive films, optoelectronic devices, flexible sensors, energy harvesting and storage devices, and bioinspired electronic devices. Finally,the challenges and perspectives of nanoimprint lithography in flexible electronic systems are discussed.展开更多
Position controlled nanowire growth is important for nanowire-based optoelectronic components which rely on light emission or light absorption. For solar energy harvesting applications, dense arrays of nanowires are n...Position controlled nanowire growth is important for nanowire-based optoelectronic components which rely on light emission or light absorption. For solar energy harvesting applications, dense arrays of nanowires are needed; however, a major obstacle to obtaining dense nanowire arrays is seed particle displacement and coalescing during the annealing stage prior to nanowire growth. Here, we explore three different strategies to improve pattern preservation of large-area catalyst particle arrays defined by nanoimprint lithography for nanowire growth. First, we see that heat treating the growth substrate prior to nanoimprint lithography improves pattern preservation. Second, we explore the possibility of improving pattern preservation by fixing the seed particles in place prior to annealing by modifying the growth procedure. And third, we show that a SiNx growth mask can fully prevent seed particle displacement. We show how these strategies allow us to greatly improve the pattern fidelity of grown InP nanowire arrays with dimensions suitable for solar cell applications, ultimately achieving 100% pattern preservation over the sampled area. The generic nature of these strategies is supported through the synthesis of GaAs and GaP nanowires.展开更多
Soft nanoimprint lithography has been limited to ultraviolet （UV） curable resists. Here, we introduce a novel approach for soft thermal nanoimprinting. This unprecedented combination of the terms ＂soft＂ and ＂ther...Soft nanoimprint lithography has been limited to ultraviolet （UV） curable resists. Here, we introduce a novel approach for soft thermal nanoimprinting. This unprecedented combination of the terms ＂soft＂ and ＂thermal＂ for nanoimprinting became possible thanks to an innovative nanocomposite mold consisting of a flexible polydimethylsiloxane （PDMS） substrate with chemically attached rigid relief features. We used soft thermal nanoimprinting to produce high-resolution nanopatterns with a sub-100 nm feature size. Furthermore, we demonstrate the applicability of our nanoimprint approach for the nanofabrication of thermally imprinted nanopattems on non-planar surfaces such as lenses. Our new nanofabrication strategy paves the way to numerous applications that require the direct fabrication of functional nanostructures on unconventional substrates.展开更多
Metasurfaces are composed of periodic subwavelength nanostructures and exhibit optical properties that are not found in nature.They have been widely investigated for optical applications such as holograms,wavefront sh...Metasurfaces are composed of periodic subwavelength nanostructures and exhibit optical properties that are not found in nature.They have been widely investigated for optical applications such as holograms,wavefront shaping,and structural color printing,however,electron-beam lithography is not suitable to produce large-area metasurfaces because of the high fabrication cost and low productivity.Although alternative optical technologies,such as holographic lithography and plasmonic lithography,can overcome these drawbacks,such methods are still constrained by the optical diffraction limit.To break through this fundamental problem,mechanical nanopatteming processes have been actively studied in many fields,with nanoimprint lithography(NIL)coming to the forefront.Since NIL replicates the nanopattem of the mold regardless of the diffraction limit,NIL can achieve sufficiently high productivity and patterning resolution,giving rise to an explosive development in the fabrication of metasurfaces.In this review,we focus on various NIL technologies for the manufacturing of metasurfaces.First,we briefly describe conventional NIL and then present various NIL methods for the scalable fabrication of metasurfaces.We also discuss recent applications of NIL in the realization of metasurfaces.Finally,we conclude with an outlook on each method and suggest perspectives for future research on the high-throughput fabrication of active metasurfaces.展开更多
Nanoimprint lithography(NIL)has attracted attention recently as a promising fabrication method for dielectric metalenses owing to its low cost and high throughput,however,high aspect ratio(HAR)nanostructures are requi...Nanoimprint lithography(NIL)has attracted attention recently as a promising fabrication method for dielectric metalenses owing to its low cost and high throughput,however,high aspect ratio(HAR)nanostructures are required to manipulate the full 2πphase of light.Conventional NIL using a hard-polydimethylsiloxane(h-PDMS)mold inevitably incurs shear stress on the nanostructures which is inversely proportional to the surface area parallel to the direction of detachment.Therefore,HAR structures are subjected to larger shear stresses,causing structural failure.Herein,we propose a novel wet etching NIL method with no detachment process to fabricate flawless HAR metalenses.The water-soluble replica mold is fabricated with polyvinyl alcohol(PVA)which is simpler than an h-PDMS mold,and the flexibility of the PVA mold is suitable for direct printing as its high tensile modulus allows high-resolution patterning of HAR metalenses.The diffraction-limited focusing of the printed metalenses demonstrates that it operates as an ideal lens in the visible regime.This method can potentially be used for manufacturing various nanophotonic devices that require HAR nanostructures at low cost and high throughput,facilitating commercialization.展开更多
基金supported by National Natural Science Foundation of China(No.52025055 and 52275571)Basic Research Operation Fund of China(No.xzy012024024).
文摘Tilted metasurface nanostructures,with excellent physical properties and enormous application potential,pose an urgent need for manufacturing methods.Here,electric-field-driven generative-nanoimprinting technique is proposed.The electric field applied between the template and the substrate drives the contact,tilting,filling,and holding processes.By accurately controlling the introduced included angle between the flexible template and the substrate,tilted nanostructures with a controllable angle are imprinted onto the substrate,although they are vertical on the template.By flexibly adjusting the electric field intensity and the included angle,large-area uniform-tilted,gradient-tilted,and high-angle-tilted nanostructures are fabricated.In contrast to traditional replication,the morphology of the nanoimprinting structure is extended to customized control.This work provides a cost-effective,efficient,and versatile technology for the fabrication of various large-area tilted metasurface structures.As an illustration,a tilted nanograting with a high coupling efficiency is fabricated and integrated into augmented reality displays,demonstrating superior imaging quality.
基金the National Science Foundation for the partial support(NSF-2213684),and LJG acknowledges an Emmett Leith Collegiate Professorship for this writing.
文摘2025 marks the 30th anniversary of nanoimprint lithography(NIL).Since its inception in 1995,and through global efforts over the past three decades,nanoimprint has emerged as the primary alternative to extreme ultraviolet(EUV)lithography for deep-nanoscale silicon(Si)electronics.Numerous semiconductor companies have recognized NIL's manufacturing quality and are actively being evaluated for the production of the most advanced semiconductor devices.Nanoimprinting's potential extends beyond silicon chip fabrication and wafer-scale applica-tions.With its high throughput and 3D patterning capabilities,NIL is becoming a key technology for fabricating emerging devices,such as flat optics and augmented reality glasses.This review summarizes the key developments and applications of nanoimprint lithography,with a particular focus on the latest industry advancements in nano-Si device manufacturing and nanophotonics applications.
基金supported by Natural Science Foundation of Shanghai(No.11ZR1432100)Shanghai Postdoctoral Science Foundation(11R21420900)
文摘Nanoimprint lithography(NIL) is an emerging micro/nano-patterning technique,which is a high-resolution,high-throughput and yet simple fabrication process.According to International Technology Roadmap for Semiconductor(ITRS),NIL has emerged as the next generation lithography candidate for the22 nm and 16 nm technological nodes.In this paper,we present an overview of nanoimprint lithography.The classfication,research focus,critical issues,and the future of nanoimprint lithography are intensively elaborated.A pattern as small as 2.4 nm has been demonstrated.Full-wafer nanoimprint lithography has been completed on a 12-inch wafer.Recently,12.5 nm pattern resolution through soft molecular scale nanoimprint lithography has been achieved by EV Group,a leading nanoimprint lithography technology supplier.
基金supported by the Molecular Foundry,Lawrence Berkeley National Laboratory,which is supported by the Office of Science and Office of Basic Energy Sciences of the U.S.Department of Energy under Contract No.DE-AC02-05CH11231supported by National Natural Science Foundation of China (No.51573011)+2 种基金Natural Foundation of Jiangsu Province (No. BK20150272)Beijing Laboratory of Biomedical Materialsthe scholarship support from the program of the China Scholarship Council (No.201706880022) for study at Lawrence Berkeley National Laboratory
文摘The development of polymeric optical materials with a higher refractive index,transparency in the visible spectrum region and easier processability is increasingly desirable for advanced optical applications such as microlenses,image sensors,and organic light-emitting diodes.Most acrylates have a low refractive index(around 1.50)which does not meet the high perfo rmance requirements of advanced optical materials.In this research,three novel acrylates were synthesized via a facile one-step approach and used to fabricate optical transparent polymers.All of the polymers reveal good optical properties including high transparency(≥90%)in the visible spectrum region and high refractive index values(1.6363)at 550 nm.Moreover,nanostructures of these acrylate polymers with various feature sizes including nanogratings and photonic crystals were successfully fabricated using nanoimprint lithography.These results indicate that these acrylates can be used in a wide range of optical and optoelectronic devices where nanopatterned films with high refractive index and transparency are required.
基金supported by the National Natural Science Foundation of China(Grant No.10902083)the Program for New Century Excellent Talent in University of Ministry of Education of China(Grant No.NCET-12-1046)+1 种基金the Program for New Scientific and Technological Star of Shaanxi Province,China(Grant No.2012KJXX-39)the Program for Natural Science Basic Research Plan in Shaanxi Province,China(Grant No.2014JQ1036)
文摘The effects of a twin boundary（TB） on the mechanical properties of two types of bicrystal Al thin films during the nanoimprint process are investigated by using molecular dynamics simulations.The results indicate that for the TB direction parallel to the imprinting direction,the yield stress reaches the maximum for the initial dislocation nucleation when the mould directly imprints to the TB,and the yield stress first decreases with the increase of the marker interval and then increases.However,for the TB direction perpendicular to the imprinting direction,the effect of the TB location to the imprinting forces is very small,and the yield stress is greater than that with the TB direction parallel to the imprinting direction.The results also demonstrate that the direction of the slip dislocations and the deformation of the thin film caused by spring-back are different due to various positions and directions of the TB.
基金the College of Engineering and School of Industrial Engineering at Purdue University for startup supportpartially supported by the National Science Foundation under Grant CMMI-1762698+3 种基金financial assistance from ONR NEPTUNE program National Science Foundation under Grant CMMI-1538360supported by the Louis Beecherl, Jr. Endowment Fundsthe College of Engineering and School of Materials Engineering at Purdue University for startup supportsupported through computational resources provided by the Information Technology department at Purdue University。
文摘The low-dimensional,highly anisotropic geometries,and superior mechanical properties of one-dimensional(1D) nanomaterials allow the exquisite strain engineering with a broad tunability inaccessible to bulk or thin-film materials.Such capability enables unprecedented possibilities for probing intriguing physics and materials science in the 1-D limit.Among the techniques for introducing controlled strains in 1D materials,nanoimprinting with embossed substrates attracts increased attention due to its capability to parallelly form nanomaterials into wrinkled structures with controlled periodicities,amplitudes,orientations at large scale with nanoscale resolutions.Here,we systematically investigated the strain-engineered anisotropic optical properties in Te nanowires through introducing a controlled strain field using a resist-free thermally assisted nanoimprinting process.The magnitude of induced strains can be tuned by adjusting the imprinting pressure,the nanowire diameter,and the patterns on the substrates.The observed Raman spectra from the chiral-chain lattice of 1D Te reveal the strong lattice vibration response under the strain.Our results suggest the potential of 1D Te as a promising candidate for flexible electronics,deformable optoelectronics,and wearable sensors.The experimental platform can also enable the exquisite mechanical control in other nanomaterials using substrate-induced,on-demand,and controlled strains.
基金This project is supported by National Hi-tech Research and Development Program of China (863 Program, No. 2002AA404430)National Natural Science Foundation of China (No. 50475137).
文摘Nanoimprint lithography （NIL） is recognized as one of the most promising candidates for the next generation lithography （NGL） to obtain sub-100 nm patterns because of its simplicity, high-throughput and low-cost. While substantial effort has been expending on NIL for producing smaller and smaller feature sizes, considerably less effort has been devoted to the equally important issue—alignment between template and substrate. A homemade prototype nanoimprint lithography tool with a high precision automatic alignment system based on Moiré signals is presented. Coarse and fine pitch gratings are adopted to produce Moiré signals to control macro and micro actuators and enable the substrate to move towards the desired position automatically. Linear motors with 300 mm travel range and 1 μm step resolution are used as macro actuators, and piezoelectric translators with 50 μm travel range and 1 nm step resolution are used as micro actuators. In addition, the prototype provides one translation （z displacement） and two tilting motion（α and β ） to automatically bring uniform intact contact between the template and substrate surfaces by using a flexure stage. As a result, 10 μm coarse alignment accuracy and 20 nm fine alignment accuracy can be achieved. Finally, some results of nanostructures and micro devices such as nanoscale trenches and holes, gratings and microlens array fabricated using the prototype tool are presented, and hot embossing lithography, one typical NIL technology, are depicted by taking nanoscale gratings fabrication as an example.
基金financed by the National Natural Science Foundation of China(Nos.52025055 and 5227050783)。
文摘Surface nanopatterning of semiconductor optoelectronic devices is a powerful way to improve their quality and performance.However,photoelectric devices’inherent stress sensitivity and inevitable warpage pose a huge challenge on fabricating nanostructures large-scale.Electric-driven flexible-roller nanoimprint lithography for nanopatterning the optoelectronic wafer is proposed in this study.The flexible nanoimprint template twining around a roller is continuously released and recovered,controlled by the roller’s simple motion.The electric field applied to the template and substrate provides the driving force.The contact line of the template and the substrate gradually moves with the roller to enable scanning and adapting to the entire warped substrate,under the electric field.In addition,the driving force generated from electric field is applied to the surface of substrate,so that the substrate is free from external pressure.Furthermore,liquid resist completely fills in microcavities on the template by powerful electric field force,to ensure the fidelity of the nanostructures.The proposed nanoimprint technology is validated on the prototype.Finally,nano-grating structures are fabricated on a gallium nitride light-emitting diode chip adopting the solution,achieving polarization of the light source.
基金Project (No VENI 08120) supported by the Dutch National Scientific Foundation NWO and Dutch Technology Foundation STW
文摘Dislocation dynamics simulations are performed to investigate the effect of template shape on the nanoimprinting of metal layers. To this end, metal thin films are imprinted by a rigid template made of an array of equispaced indenters of various shapes, i.e., rectangular, wedge, and circular. The geometry of the indenters is chosen such that the contact area is approximately the same at the final imprinting depth. Results show that, for all template shapes, the final patterns strongly depend on the dislocation activity, and that each imprint differs from the neighboring ones. Large material pile ups appear between the imprints, such that polishing of the metal layer is suggested for application of the patterns in electronics. Rectangular indenters require the lowest imprinting force and achieve the deepest retained imprints.
基金Supported by National Natural Science Foundation of China (No. E05020203) , "863" National Hi-Tech Program(No.2002AA420050) and "973" National Key Basic Research Program ( No. 2003CB716202).
文摘To tackle the demoulding and conglutinating problem with the resist and hard mold in the nanoimprint lithography process, a soft mould can be used to demould and reduce the macro or mi- cro mismatch between mould bottom surface and wafer top surface. In nanoimprint lithography process, a mathematical equation is formulated to demonstrate the relation between the residual re- sist thickness and the pressing force during pressing the mould toward the resist-coated wafer. Based on these analytical studies, a new imprint process, which includes a pre-cure release of the pressing force, was proposed for the high-conformity transfer of nano-patterns from the mould to the wafer. The results of a series of imprint experiments showed that the proposed loading process could meet the requirements for the imprint of different patterns and feature sizes while maintaining a uniform residual resist and non-distorted transfer of nano-patterns from the mould to the resist- coated wafer.
文摘Soft lithography is a low-cost and convenient method for the forming and manufacturing of micro/ nanostructures compared to the traditional optical lithography. In soft lithography, poly（dimethylsiloxane） （PDMS） stamps with relief structures have been widely used to transfer patterns. The traditional fabrication approach of PDMS stamps is time-consuming since the master has been occupied during the curing process. By adding and repeating fast nanoimprint step, many intermediate polymeric molds can be produced from the master and these molds can then be employed to replicate more PDMS stamps while the time used is close to that of the common way. We demonstrated this idea by three masters which were made by the DEM （Deepetching, Electroforming and Microreplicating） and FIB （Focused Ion Beam） techniques. The photos show that the patterns on the PMDS stamps successfully duplicated patterns on the origin masters.
基金supported by the National Key R&D Program of China(2022YFE0104100)National Natural Science Foundation of China(52073242,22075184,and 22271153)+4 种基金Hong Kong Research Grants Council(PolyU15307321)RGC Senior Research Fellowship Scheme(SRFS2021-5S01)Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials(2019B121205002)Research Centre for Nanoscience and Nanotechnology(CE2H),PolyU Shenzhen Research Institute(J2023A006)Miss Clarea Au for the Endowed Professorship in Energy(847S)。
文摘L10-FePt-type bit-patterned media has provided a promising alternative for ultrahigh-density magnetic recording systems in the current digital era,but rapid fabrication of magnetic patterns with hyperfine bit islands is still challenging,especially with the target for miniaturization and scalable production simultaneously.Herein,Fe,Pt-containing block copolymers were utilized as single-source precursors for solution-processable patterning and subsequent generation of the demanding magnetic FePt dots by in situ pyrolysis.High-throughput nanoimprint lithography was initially employed to fabricate the predefined bit cells precisely,and then the intrinsic self-assembly of phase-separated block copolymers further drove the formation of accurate bit islands.Benefiting from the synergistic effect of top-down lithographic approach and bottom-up self-assembly,the customizable patterns could be achieved for large-scale mass production in targeted areas,but high-density isolated dots could also be accurately aligned along the patterned features after subsequent self-assembly.This reliable strategy would provide a good avenue to precisely construct ultrahigh-density magnetic data storage devices.
基金This work was partially funded by DARPA Contract No.N66001-02-C-8011NIST Advanced Technology Program Contract No.70NANB4H3012+2 种基金US DoD Contract No.N66001-06-C-2003DARPA A2P Program administered by AFRL Contract No.FA8650-15-C-7542by the National Science Foundation under Cooperative Agreement No.EEC-1160494.
文摘This article discusses the transition of a form of nanoimprint lithography technology,known as Jet and Flash Imprint Lithography(J-FIL),from research to a commercial fabrication infrastructure for leading-edge semiconductor integrated circuits(ICs).Leadingedge semiconductor lithography has some of the most aggressive technology requirements,and has been a key driver in the 50-year history of semiconductor scaling.Introducing a new,disruptive capability into this arena is therefore a case study in a“highrisk-high-reward”opportunity.This article first discusses relevant literature in nanopatterning including advanced lithography options that have been explored by the IC fabrication industry,novel research ideas being explored,and literature in nanoimprint lithography.The article then focuses on the J-FIL process,and the interdisciplinary nature of risk,involving nanoscale precision systems,mechanics,materials,material delivery systems,contamination control,and process engineering.Next,the article discusses the strategic decisions that were made in the early phases of the project including:(i)choosing a step and repeat process approach;(ii)identifying the first target IC market for J-FIL;(iii)defining the product scope and the appropriate collaborations to share the risk-reward landscape;and(iv)properly leveraging existing infrastructure,including minimizing disruption to the widely accepted practices in photolithography.Finally,the paper discusses the commercial J-FIL stepper system and associated infrastructure,and the resulting advances in the key lithographic process metrics such as critical dimension control,overlay,throughput,process defects,and electrical yield over the past 5 years.This article concludes with the current state of the art in J-FIL technology for IC fabrication,including description of the high volume manufacturing stepper tools created for advanced memory manufacturing.
基金supported by the National Basic Research Program of China ("973" Program) (Grant No. 2011CB302105)the Fundamental Research Funds for the Central Universities (Grant No. DUT10ZD104)
文摘In this paper,the replication process of large area nanoimprint stamp with small critical dimension(CD) loss was investigated,using the thin residual layer nanoimprint lithography(NIL) technology.The residual layer thickness was optimized by changing the spin-coated resist thickness.The dependences of the residual layer etching rate on gas flow,chamber pressure,and RF power were investigated,and the optimized process conditions were established.By means of the thin residual layer NIL technique and optimized residual layer etching process,large area stamp with small CD loss and multi-orientation patterns was successfully replicated on 2-inch SiO2/Si wafer.The CD loss was controlled within 5 nm.The replicated stamp showed high performance in the patterning with thermal NIL.The replication process reported in this work could also be used to fabricate large area nanostructures with small CD loss.
基金supported by the National Natural Science Foundation of China(Grant Nos.91323303,51421004,51522508)
文摘Flexible electronics have received considerable attention in academies and industries for their promising applications in enormous fields, such as flexible displays, wearable sensors, artificial skins, and flexible energy devices. Challenges remain in developing a flexible and scalable manufacturing method to facilitate the fabrication of multi-functional structures in a flexible electronic system. Nanoimprint lithography is a high resolution and low-cost approach to fabricate nanostructures over a large area. This paper reviews recent progress of nanoimprint lithography and its applications in flexible electronics. The basic principles, classification, research focus, and critical issues of nanoimprint lithography are elaborated. Then, the advantages of nanoimprint lithography are demonstrated in several typical applications related to flexible electronics, including conductive films, optoelectronic devices, flexible sensors, energy harvesting and storage devices, and bioinspired electronic devices. Finally,the challenges and perspectives of nanoimprint lithography in flexible electronic systems are discussed.
文摘Position controlled nanowire growth is important for nanowire-based optoelectronic components which rely on light emission or light absorption. For solar energy harvesting applications, dense arrays of nanowires are needed; however, a major obstacle to obtaining dense nanowire arrays is seed particle displacement and coalescing during the annealing stage prior to nanowire growth. Here, we explore three different strategies to improve pattern preservation of large-area catalyst particle arrays defined by nanoimprint lithography for nanowire growth. First, we see that heat treating the growth substrate prior to nanoimprint lithography improves pattern preservation. Second, we explore the possibility of improving pattern preservation by fixing the seed particles in place prior to annealing by modifying the growth procedure. And third, we show that a SiNx growth mask can fully prevent seed particle displacement. We show how these strategies allow us to greatly improve the pattern fidelity of grown InP nanowire arrays with dimensions suitable for solar cell applications, ultimately achieving 100% pattern preservation over the sampled area. The generic nature of these strategies is supported through the synthesis of GaAs and GaP nanowires.
基金This work was supported by Adelis Foundation for Renewable Energy （No. 2021611） and Israel Science Foundation （No. 1401/15）. Viraj Bhingardive thanks the Negev-Tsin Scholarship for its support.
文摘Soft nanoimprint lithography has been limited to ultraviolet （UV） curable resists. Here, we introduce a novel approach for soft thermal nanoimprinting. This unprecedented combination of the terms ＂soft＂ and ＂thermal＂ for nanoimprinting became possible thanks to an innovative nanocomposite mold consisting of a flexible polydimethylsiloxane （PDMS） substrate with chemically attached rigid relief features. We used soft thermal nanoimprinting to produce high-resolution nanopatterns with a sub-100 nm feature size. Furthermore, we demonstrate the applicability of our nanoimprint approach for the nanofabrication of thermally imprinted nanopattems on non-planar surfaces such as lenses. Our new nanofabrication strategy paves the way to numerous applications that require the direct fabrication of functional nanostructures on unconventional substrates.
基金the National Research Foundation(NRP)grant(NRF-2019R1A2C3003129)flinded by the Ministry of Science and ICT,Republic of Korea.T.L.acknowledges the NRF Global Ph.D.fellowship(NRF-2019H1 A2A 1076295)funded by the Ministry of Education,Republic of Korea.
文摘Metasurfaces are composed of periodic subwavelength nanostructures and exhibit optical properties that are not found in nature.They have been widely investigated for optical applications such as holograms,wavefront shaping,and structural color printing,however,electron-beam lithography is not suitable to produce large-area metasurfaces because of the high fabrication cost and low productivity.Although alternative optical technologies,such as holographic lithography and plasmonic lithography,can overcome these drawbacks,such methods are still constrained by the optical diffraction limit.To break through this fundamental problem,mechanical nanopatteming processes have been actively studied in many fields,with nanoimprint lithography(NIL)coming to the forefront.Since NIL replicates the nanopattem of the mold regardless of the diffraction limit,NIL can achieve sufficiently high productivity and patterning resolution,giving rise to an explosive development in the fabrication of metasurfaces.In this review,we focus on various NIL technologies for the manufacturing of metasurfaces.First,we briefly describe conventional NIL and then present various NIL methods for the scalable fabrication of metasurfaces.We also discuss recent applications of NIL in the realization of metasurfaces.Finally,we conclude with an outlook on each method and suggest perspectives for future research on the high-throughput fabrication of active metasurfaces.
基金H.L.acknowledges the Technology Innovation program(20016234)funded by the Ministry of Trade and Industry&Energy(MOTIE)and the National Research Foundation(NRF)grants(NRF-2019K1A4A7A02113032,NRF-2022M3H4A1A02046445,NRF-2018M3D1A1058997)funded by the Ministry of Science and ICT(MSIT)of the Korean governmentJ.R.acknowledges the POSCO-POSTECH-RIST Convergence Research Center program funded by POSCO,an industry-university strategic grant funded by Samsung Display,and the NRF grants(NRF-2022M3C1A3081312,NRF-2022M3H4A1A02074314,NRF-2019R1A5A8080290,CAMM-2019M3A6B3030637)funded by the MSIT of the Korean government+1 种基金C.W.Q.acknowledges the support by AME Individual Research Grant(IRG)funded by A*STAR,Singapore(Grant No.A2083c0060).J.K.acknowledges the POSTECH Alchemist fellowship.
文摘Nanoimprint lithography(NIL)has attracted attention recently as a promising fabrication method for dielectric metalenses owing to its low cost and high throughput,however,high aspect ratio(HAR)nanostructures are required to manipulate the full 2πphase of light.Conventional NIL using a hard-polydimethylsiloxane(h-PDMS)mold inevitably incurs shear stress on the nanostructures which is inversely proportional to the surface area parallel to the direction of detachment.Therefore,HAR structures are subjected to larger shear stresses,causing structural failure.Herein,we propose a novel wet etching NIL method with no detachment process to fabricate flawless HAR metalenses.The water-soluble replica mold is fabricated with polyvinyl alcohol(PVA)which is simpler than an h-PDMS mold,and the flexibility of the PVA mold is suitable for direct printing as its high tensile modulus allows high-resolution patterning of HAR metalenses.The diffraction-limited focusing of the printed metalenses demonstrates that it operates as an ideal lens in the visible regime.This method can potentially be used for manufacturing various nanophotonic devices that require HAR nanostructures at low cost and high throughput,facilitating commercialization.
