Search

The extreme ultraviolet (EUV) nanolithography technology is the keystone for developing the next-generation chips. As conventional chemically amplified resists are approaching the resolution limit, metal-containing photoresists, especially tin-oxo clusters, seize the opportunity to embrace this challenge owing to their small sizes, precise atomic structures, and strong EUV absorption. However, atomistic insights into the mechanism for regulating their photolithographic behavior are lacking. Herein, we systematically explored the effects of ligands, counterions, and endohedral doping on the photophysical properties of tin-oxo cage clusters by first-principles calculations combined with molecular dynamics simulations. Photoresists assembled by allyl-protected clusters with small-size OH− or Cl− counterions have a high absorption coefficient at the EUV wavelength of 13.5 nm and a low energy cost for ligand detachment and superior stability to ensure high sensitivity and strong etch resistance, respectively. The photoresist performance can further be improved by endohedral doping of the metal-oxo nanocage with Ag+ and Cd2+ ions, which exhibit superatomic characteristics and are likely to be synthesized in laboratory. These theoretical results provide useful guidance for modification of metal-oxo clusters for high-resolution EUV photolithography. [ABSTRACT FROM AUTHOR]

The dissociative photoionization of phenyl triflate (C6H5OSO2CF3), a neutral photoacid generator used in photolithography, was investigated in a gas phase experiment employing extreme ultraviolet (EUV) synchrotron radiation at 92 eV and photoelectron–photoion coincidence detection. The interaction of EUV photons with the molecule leads almost exclusively to dissociation, which is dominated by a sequential fragmentation mechanism, in which SO2, CF3, CO, and C2H2 are lost. For lithographic purposes, the lack of the observation of a fragment that could serve as a precursor for the formation of triflic acid means that the effective photoacid generator concentration in a photoresist is reduced, impacting its patterning performance in EUV lithography. A better understanding of the dissociative photoionization of photoresist components and proxies thereof can provide a crucial handle that guides the design of photoresists for the upcoming technology nodes with ever decreasing feature sizes for more powerful computer chips. [ABSTRACT FROM AUTHOR]

A home‐built compact system that functions as both a transfer stage for deterministic transfer processes and a mask aligner for contact photolithography, is constructed. The precision translation sample stage and optical microscope are shared between the two modes. In the transfer mode, assisted by either an adhesive or a heating element, the setup has been used to deterministically transfer freestanding semiconductors, 2D materials, and van der Waals electrodes. When configured in photolithography mode, the proposed instrument has been employed to fabricate various microscale patterns and devices, with minimum feature sizes of 1–2 μm achieved. The prototype instrument provides a feasible solution for performing high‐quality deterministic transfer and photolithography processes on one single tool in‐house. [ABSTRACT FROM AUTHOR]

Nanotopographic surfaces are a powerful tool for studying and controlling cell behavior. However, the fabrication of nanotopographic master patterns using conventional photolithography is expensive, which limits the range of designs that can be explored. In this study, a method is demonstrated for the photoreshaping of large‐area patterns of nanoridges. The original master pattern is created using conventional lithography, and an azopolymer replica is prepared using soft lithography. The manipulation of the nanoridges is achieved by projecting light with specific polarizations and exposure times, resulting in controllable widening, buckling, or removal of the ridges. The reprogrammed azopolymer master patterns can then be replicated, creating reproducible new nanotopographies that can be transferred into other materials using a molding procedure. Diffraction can be used for in situ monitoring of the reprogramming during exposure. Image‐analysis methods are used to characterize buckled ridges as a function of exposure time. The response of MCF10A epithelial cells are investigated to buckled nanoridges. A substantial impact of buckling on the dynamics and location of actin polymerization, as well as on the distribution and lengths of contiguous polymerized regions is also observed. [ABSTRACT FROM AUTHOR]

In this paper, multifunctional, multilevel phase plates of quartz substrate were efficiently prepared by using a newly developed polygon scanner-based femtosecond laser photolithography system combined with inductively coupled discharge plasma reactive-ion etching (ICP-RIE) technology. The femtosecond laser photolithography system can achieve a scanning speed of 5 m/s and a preparation efficiency of 15 cm2/h while ensuring an overlay alignment accuracy of less than 100 nm and a writing resolution of 500 nm. The ICP-RIE technology can control the etching depth error within ±5 nm and the mask-to-mask edge error is less than 1 μm. An 8-level Fresnel lens phase plate with a focal length of 20 mm and an 8-level Fresnel axicon phase plate with a cone angle of 5° were demonstrated. The diffraction efficiency was greater than 93%, and their performance was tested for focusing and glass cutting, respectively. Combined with the high-speed femtosecond laser photolithography system's infinite field-of-view (IFOV) processing capability, the one-time direct writing preparation of phase plate masks of different sizes was realized on a 6-inch wafer. This is expected to reduce the production cost of quartz substrate diffractive optical elements and promote their customized mass production. [ABSTRACT FROM AUTHOR]

Semiconducting photoresists hold great promise for scale‐up manufacturing of organic field‐effect transistors (OFETs) for integrated organic electronics. While photolithographic p‐type OFETs have achieved a considerable balance among patterning precision, electrical properties and process stability, it remains challenging for n‐type OFETs due to the inherent limited mobility and ambient instability. Herein, a n‐type semiconducting photoresist (SPr) is developed that is compatible with photolithography procedures. By utilizing the solvent‐driven force, a self‐encapsulated blend film with gradient semiconductor phase is prepared, where the underneath transistor active layer is protected by the upper cross‐linked network, avoiding solvent erosion and air doping. As such, a mobility up to 1.1 cm2 V−1 s−1 that is comparable with amorphous Si is achieved, with remained mobility by ≈90% after long‐term exposure to developer and stripper or atmospheric conditions. The sub‐micrometer patterning accuracy of SPr enables the fabrication of organic transistor arrays with a density of 9 × 105 units cm−1, which is comparable to other state‐of‐the‐art devices fabricated by the printing or photolithography, demonstrating immense potential in integrated organic electronics. [ABSTRACT FROM AUTHOR]

In recent years, the field of micro- and nanochannel fabrication has seen significant advancements driven by the need for precision in biomedical, environmental, and industrial applications. This review provides a comprehensive analysis of emerging fabrication technologies, including photolithography, soft lithography, 3D printing, electron-beam lithography (EBL), wet/dry etching, injection molding, focused ion beam (FIB) milling, laser micromachining, and micro-milling. Each of these methods offers unique advantages in terms of scalability, precision, and cost-effectiveness, enabling the creation of highly customized micro- and nanochannel structures. Challenges related to scalability, resolution, and the high cost of traditional techniques are addressed through innovations such as deep reactive ion etching (DRIE) and multipass micro-milling. This paper also explores the application potential of these technologies in areas such as lab-on-a-chip devices, biomedical diagnostics, and energy-efficient cooling systems. With continued research and technological refinement, these methods are poised to significantly impact the future of microfluidic and nanofluidic systems. [ABSTRACT FROM AUTHOR]

Quantum dots (QDs) have become the most valuable luminescent materials due to their excellent optical properties, such as high color purity, high photoluminescence quantum yield (PLQY), and tunable luminescence spectra. QDs‐based display devices have been used commercially and have shown outstanding advantages such as wide color gamut, high brightness, etc. However, for high‐end displays such as micro‐light‐emitting diodes (Micro‐LED), fine precise patterning of QDs is still a prerequisite and key challenge. Recently, direct photolithography, a method based on photochemical reactions of QDs photoresist (QDPR), has been considered as the most potential patterning technology to achieve high resolution and high‐throughput. This review focuses on the recent progress of QDPR from the point of view of different photochemical reaction mechanisms: starting the monomer polymerization, followed by the ligand crosslinking or decomposition, and eventually introducing crosslinking additives. Furthermore, a comprehensive overview of the current applications of QDPR in displays is provided based on the different types of LED devices. Finally, existing problems in QDs direct photolithography are discussed, along with possible reasons and solutions. This review is expected to accelerate the development of direct photolithography patterning method and provide general guidance for the further design of QDPR for high‐end displays. [ABSTRACT FROM AUTHOR]

The development of manufacturable and scalable integrated nonlinear photonic materials is driving key technologies in diverse areas, such as high-speed communications, signal processing, sensing, and quantum information. Here, we demonstrate a nonlinear platform—InGaP-on-insulator—optimized for visible-to-telecommunication wavelength χ (2) nonlinear optical processes. In this work, we detail our 100 mm wafer-scale InGaP-on-insulator fabrication process realized via wafer bonding, optical lithography, and dry-etching techniques. The resulting wafers yield 1000 s of components in each fabrication cycle, with initial designs that include chip-to-fiber couplers, 12.5-cm-long nested spiral waveguides, and arrays of microring resonators with free-spectral ranges spanning 400–900 GHz. We demonstrate intrinsic resonator quality factors as high as 324 000 (440 000) for single-resonance (split-resonance) modes near 1550 nm corresponding to 1.56 dB/cm (1.22 dB/cm) propagation loss. We analyze the loss vs waveguide width and resonator radius to establish the operating regime for optimal 775–1550 nm phase matching. By combining the high χ (2) and χ (3) optical nonlinearity of InGaP with wafer-scale fabrication and low propagation loss, these results open promising possibilities for entangled-photon, multi-photon, and squeezed light generation. [ABSTRACT FROM AUTHOR]

Advanced photoresists must satisfy stringent sensitivity requirements while maintaining the ability to print ever‐shrinking critical dimensions. However, the unavoidable acid diffusion associated with chemically amplified photoresists has led to a trade‐off between resolution, line‐edge roughness, and sensitivity, which presents a significant challenge for high‐resolution lithography. To address this issue, a novel class of alkene‐functionalized nonionic perfluorinated photoacid generators (PAGs) is developed. These fluorine‐rich compounds significantly enhance the photochemical reactivity due to the introduction of abundant F‐elements, thereby improving sensitivity. Upon irradiation by ultraviolet light or electrons, they generate long‐chain perfluorinated sulfonic acids with large sizes and minimal diffusion ranges, effectively suppressing acid diffusion. Furthermore, by employing these polymerizable PAG monomers, PAG‐bound polymers are synthesized that are likely to achieve higher resolution by minimizing acid diffusion. Lithography performance demonstrated patterning of sub‐45 nm lines at an electron beam dose of 29 µC cm−2. Overall, the developed perfluorinated PAGs and PAG‐bound polymer photoresists are promising candidates for achieving high‐sensitivity and high‐resolution nano‐patterning. [ABSTRACT FROM AUTHOR]

Mode‐division multiplexing (MDM) technology, as a new way to increase the communication capacity of a single wavelength carrier, has attracted increasing attention. As a fundamental building block for MDM communication systems, multimode optical switch is playing an important role for routing the increasingly complex network. However, it is still very challenging to achieve a multimode optical switch with high flexibility and low power‐consumption in a large bandwidth. Here, a 1 × 2 dual‐mode optical switch is proposed and experimentally demonstrated, where the E11 and E21 modes can be switched output from either of the two output ports simultaneously or individually with low power‐consumption. For the proposed dual‐mode optical switch, three asymmetric Y‐junctions are used as mode (de)multiplexers, two Mach–Zehnder interferometers form a single‐mode switch matrix, and a 2 × 2 multimode interferometer is used as the waveguide crossing. The device is fabricated with simple photolithography and wet‐etching methods. The measurement results show that the driving powers of the device are lower than 8.4 mW, and the crosstalks are less than −12.4 dB in the wavelength range of 1500–1600 nm. By implementing the dynamic control of resources between the guided modes, the proposed device can greatly improve the flexibility and efficiency of reconfigurable MDM networks. [ABSTRACT FROM AUTHOR]

Fluorescent lead halide perovskite quantum dots (LH PQDs) micropatterns hold great potential for photonic applications. However, current photolithography for LH PQDs micropatterning is hindered by their incompatibility with traditional photolithography methods, which involve development processes using numerous solvents and exhibit poor stability due to the ionic characteristics of LH PQDs. Herein, a direct in situ photolithography to fabricate CsPbBr3 PQDs micropatterns based on ultraviolet‐C light‐driven debromination is developed. Using this approach, fluorescent CsPbBr3 PQDs micropatterns with high theoretical information storage capacity (up to 10750205) can be achieved in a single step, without the need for tedious development processes. Furthermore, the fabricated CsPbBr3 PQDs micropatterns show high stability, remaining undamaged even after immersion in water for 6 months. The combination of excellent optical properties, development‐free process, high stability, and low cost makes the in situ photolithography strategy very promising for patterning LH PQDs toward photonic integrations. [ABSTRACT FROM AUTHOR]

Nano- and micro-carriers of therapeutic molecules offer numerous advantages for drug delivery, and the shape of these particles plays a vital role in their biodistribution and their interaction with cells. However, analysing how microparticles are taken up by cells presents methodological challenges. Qualitative methods like microscopy provide detailed imaging but are time-consuming, whereas quantitative methods such as flow cytometry enable high-throughput analysis but struggle to differentiate between internalised and surface-bound particles. Instead, imaging flow cytometry combines the best of both worlds, offering high-resolution imaging with the efficiency of flow cytometry, allowing for quantitative analysis at the single-cell level. This study focuses on fluorescently labelled silicon oxide microchips of various morphologies but related surface areas and volumes: rectangular cuboids and apex-truncated square pyramid microchips fabricated using photolithography techniques, offering a reliable basis for comparison with the more commonly studied spherical particles. Imaging flow cytometry was utilised to evaluate the effect of particle shape on cellular uptake using RAW 264.7 cells and revealed phagocytosis of particles with all shapes. Increasing the particle dose enhanced the uptake, while macrophage stimulation had minimal effect. Using a ratio particle:cell of 10:1 cuboids and spheres showed an uptake rate of approximately 50%, in terms of the percentage of cells with internalised particles, and the average number of particles taken up per cell ranging from about 1–1.5 particle/cell for all the different shapes. This study indicates how differently shaped micro-carriers offer insights into particle uptake variations, demonstrating the potential of non-spherical micro-carriers for precise drug delivery applications. [ABSTRACT FROM AUTHOR]

Photonic crystal (PhC) structures generated through periodic surface nanostructuring are pivotal for controlling light-matter interactions. These structures are essential for reducing high surface reflectivity in semiconductor optical devices, enhancing light absorption in photovoltaic cells, and improving light extraction in LEDs. Although various methods for PhC fabrication are well-documented, the use of single-pulse laser interference lithography (LIL) with commercial photoresists remains unexplored. Single nanosecond pulses for photoresist exposure offer significant advantages, including high throughput for large-scale patterning and reduced dependence on stable optical platforms. In this study, we used single-pulse LIL to fabricate antireflective PhC structures on GaAs substrates using a commercial photoresist. This process involved exposing the photoresist to single 7 nanosecond pulses at a wavelength of 355 nm, with relatively low energy levels. High-quality nanohole arrays were subsequently created via inductively coupled plasma (ICP) etching. Reflectivity analysis revealed that these structures reduced the average reflectance of GaAs to below 5% across the visible wavelength range of 450-700 nm. This work is crucial for optimizing current photonic technologies and advancing future devices with enhanced light management capabilities. [ABSTRACT FROM AUTHOR]

Ultra-precision measurement and manufacturing need high-precision machines, just as a photolithography machine needs air bearings. In gas lubrication, the use of compound restrictors with recesses has been widely proven to be an effective method to improve stiffness, which directly affects the accuracy of the machine. However, determination of the structural parameters of recesses is lacking in theoretical models. This paper has established a mechanical property model for a small-scale guideway, which can respond to the variation in force caused by micron-level changes in the recesses' depth. To meet the requirements of high positioning accuracy and movement accuracy, this paper puts forward a high-stiffness guideway without an air tube. In order to improve rotational stiffness and determine the structural parameters of recesses, this paper found a guideway with the optimal gradient depth of recesses. Both AFVM (adaptive finite volume method) research and experimental results show that the gradient depth of recesses could significantly improve the rotational stiffness of guideways without air tubes. [ABSTRACT FROM AUTHOR]

The subpixel size of high-resolution organic light-emitting diode (OLED) microdisplays measures a few micrometers. To achieve a full-color microdisplay, the current preference is to use photolithography technology on a white OLED instead of using a fine metal mask for patterning. The application of photolithography techniques allows for the creation of microcavity structures or color filters (CFs) to enhance color purity in each emitted color. This paper focuses on investigating specialized OLED device structures for high-resolution microdisplays. The characteristics of each structure, including efficiency and color gamut, are thoroughly discussed. The structure, combining microcavity and CF, achieves the widest color gamut, while microcavity structures show higher efficiency compared to CF-only structures. Tandem structures are also considered for improved efficiency and stability. [ABSTRACT FROM AUTHOR]

This paper presents a novel design of the device to generate microspheres or micro-droplets based on the membrane emulsification principle. Specifically, the novelty of the device lies in a proposed two-layer or stepwise (by generalization) membrane structure. An important benefit of the stepwise membrane is that it can be fabricated with the low-cost material (SU-8) and using the conventional lithography technology along with a conventional image-based alignment technique. The experiment to examine the effectiveness of the proposed membrane was conducted, and the result shows that microspheres with the size of 2.3 μm and with the size uniformity of 0.8 μm can be achieved, which meets the requirements for most applications in industries. It is noted that the traditional membrane emulsification method can only produce microspheres of around 20 μm. The main contribution of this paper is thus the new design principle of membranes (i.e., stepwise structure), which can be made by the cost-effective fabrication technique, for high performance of droplets production. [ABSTRACT FROM AUTHOR]

The development of highly efficient, solution-processable, and environmentally stable perovskite quantum dots (PQDs) is crucial for their accurate high-resolution patterning and subsequently enabling the practical deployment of PQD based emissive display devices. This study presents an innovative strategy for integrating all-inorganic PQDs and ultraviolet (UV) crosslinkable acrylate polymer at a structural and functional level. The achievement is accomplished by meticulous design and one-pot synthesis of UV-crosslinkable CsPbX3 (X = Cl, Br, I) PQDs solution, which exhibit outstanding environmental stability. Leveraging the solution-processable characteristics of the resulting UV-crosslinkable PQDs, precise patterning of high-resolution (2 µm, 7608 pixels in.−1) and colorful PQDs microarrays can be readily achieved through inkjet printing and high-throughput photolithography (~ 2 µm in pitch line/space patterning). The UV cross-linked process guarantees a homogeneous distribution of PQDs, effectively mitigating coffee ring effect and improving the overall quality of stereoscopic microarrays. The photo-cured PQDs film, which undergoes free radical photopolymerization, displays an impressive photoluminescence quantum yield (PL QY) of up to 89.2%, reaching 98% of the value observed in the solution state. The approach outlined in this research is both cost-effective and pragmatic, exhibiting tremendous promise for diverse system-level integrated optoelectronic devices, such as ultra-high-resolution micro-light-emitting device (micro-LED) displays. [ABSTRACT FROM AUTHOR]

We report azopyrazole photoswitches decorated with variable N‐alkyl and alkoxy chains (for hydrophobic interactions) and phenyl substituents on the pyrazoles (enabling π‐π stacking), showing efficient bidirectional photoswitching and reversible light‐induced phase transition (LIPT). Extensive spectroscopic, microscopic, and diffraction studies and computations confirmed the manifestation of molecular‐level interactions and photoisomerization into macroscopic changes leading to the LIPT phenomena. Using differential scanning calorimetric (DSC) studies, the energetics associated with those accompanying processes were estimated. The long half‐lives of Z isomers, high energy contents for isomerization and phase transitions, and the stability of phases over an extended temperature range (−60 to 80 °C) make them excellent candidates for energy storage and release applications. Remarkably, the difference in the solubility of the distinct phases in one of the derivatives allowed us to utilize it as a photoresist in photolithography applications on diverse substrates. [ABSTRACT FROM AUTHOR]

This work introduces the design, analysis, simulation, and a standard MEMS fabrication process for a three-dimensional micro-coil with a magnetic core and a digital switch configuration using a completely integrated, fully MEMS-compatible process to achieve a digitally controlled inductance. The proposed design can also be utilized as a micro-transformer. The proposed design consists of five identical 3D coils and their corresponding MEMS switches. These coils are digitally controlled to achieve a variable inductor ranging from one-fifth of the coil inductance up to five times the coil inductance. A standard five-layer Polymumps process is proposed to fabricate the micro-coils and the integrated switches. Each micro coil is anchored directly on-chip, which is connected to the input signal from one side, and the other is connected to the switch. The Ni-based magnetic core improves the coil's response by confining and guiding the magnetic field in the magnetic device compared to Si core based by more than five times. The presented coil has the number of windings limited by the designed length and the minimum spacing that can be realized by standard optical lithography. The coil's diameter is also restricted by the limits defined by optical lithography, whereas the maximum height realizable by the Polymumps process limits the height of the magnetic core and accordingly results in lower inductor performance. Based on this technique, we present coils ranging from 100 μm length and ten winding up to 1000 μm length and 100 windings. The new monolithically integrated MEMS switches act as selectors to achieve a variable inductance with digital control to allow the selection among n(n + 1)/2 inductance steps, where n is the number of coils. [ABSTRACT FROM AUTHOR]

Ferroelectric polymers have emerged as crucial materials for the development of advanced organic electronic devices. Their recent high‐end commercial applications as fingerprint sensors have only increased the amount of scientific interest around them. Despite an ever‐larger body of studies focusing on optimizing the properties of ferroelectric polymers by physical means (e. g. annealing, stretching, blending or nano‐structuring), post‐polymerization chemical modification of such polymers has only recently become a field of active study with great promise in expanding the scope of those polymers. In this work, a solution‐based post‐polymerization modification method was developed for the safe and facile grafting of a plethora of functional groups to the backbone of commercially available Poly(vinylidene fluoride‐co‐trifluoroethylene P(VDF‐co‐TrFE) ferroelectric polymers. To showcase the versatility of this approach, photosensitive groups were grafted onto the polymeric backbone, enabling them to undergo photo‐cross‐linking. Finally, these modified polymers were used as functional negative photoresists in a photolithographic process, highlighting the potential of this method to integrate ferroelectric fluorinated electroactive polymers into standard electronic microfabrication production lines. [ABSTRACT FROM AUTHOR]

Nucleic acid photolithography is the only microarray fabrication process that has demonstrated chemical versatility accommodating any type of nucleic acid. The current approach to RNA microarray synthesis requires long coupling and photolysis times and suffers from unavoidable degradation postsynthesis. In this study, we developed a series of RNA phosphoramidites with improved chemical and photochemical protection of the 2'-and 5'-OH functions. In so doing, we reduced the coupling time by more than half and the photolysis time by a factor of 4. Sequence libraries that would otherwise take over 6 hours to synthesize can now be prepared in half the time. Degradation is substantially lowered, and concomitantly, hybridization signals can reach over seven times those of the previous state of the art. Under those conditions, high-density RNA microarrays and RNA libraries can now be synthesized at greatly accelerated rates. We also synthesized fluorogenic RNA Mango aptamers on microarrays and investigated the effect of sequence mutations on their fluorogenic properties. [ABSTRACT FROM AUTHOR]

For several decades, aging in Saccharomyces cerevisiae has been studied in hopes of understanding its causes and identifying conserved pathways that also drive aging in multicellular eukaryotes. While the short lifespan and unicellular nature of budding yeast has allowed its aging process to be observed by dissecting mother cells away from daughter cells under a microscope, this technique does not allow continuous, high-resolution, and high-throughput studies to be performed. Here, we present a protocol for constructing microfluidic devices for studying yeast aging that are free from these limitations. Our approach uses multilayer photolithography and soft lithography with polydimethylsiloxane (PDMS) to construct microfluidic devices with distinct single-cell trapping regions as well as channels for supplying media and removing recently born daughter cells. By doing so, aging yeast cells can be imaged at scale for the entirety of their lifespans, and the dynamics of molecular processes within single cells can be simultaneously tracked using fluorescence microscopy. Key features This protocol requires access to a photolithography lab in a cleanroom facility. Photolithography process for patterning photoresist on silicon wafers with multiple different feature heights. Soft lithography process for making PDMS microfluidic devices from silicon wafer templates.

Electrode fabrication in microfluidic devices is often avoided due to the smaller footprint of the platform, associated complexity in the process, and absence of a well-established method. In this article a glass microchip with chemically modified and vapor deposited gold internal electrode was fabricated and used for biomolecule immobilization and electrochemical applications. The silanol (-OH) on glass surface of the microdevice was modified with (3-mercaptopropyl)trimethoxysilane prior to gold deposition to achieve a strong attachment of the metal film using the gold-thiol binding. The practical utility of the microdevice with gold surface was demonstrated by performing quantitative enzyme linked immunosorbent assay (ELISA) of human interferon gamma (IFN-γ) antigen, yielding a limit of detection (LOD) of 0.15 pg/mL compared to 4 pg/mL in the microplate assay. Additionally, the functionality of the internal electrode was established by performing cyclic voltammetry (CV) and linear sweep voltammetry (LSV) of potassium ferricyanide (III) in potassium chloride (KCl) solution using the proposed gold patterned electrode in the microchip, offering limits of detection of 0.14 and 0.11 mM for CV and LSV respectively. Both the ELISA and electrochemical assays were validated by generating calibration curves and using a control sample for the electroanalytical sensing applications. The measurements yielded experimental results that agreed with control concentration with 7% relative standard deviation (RSD). The promising reproducibility of the electrode in fabrication with no/minimum failure rate and its outstanding performance in immunosensor applications as well as an electron exchange surface makes our technique of gold electrode fabrication in microchips a state of the art. [ABSTRACT FROM AUTHOR]

Photosensitive glass-ceramics exhibit significant potential to replace silicon materials in the microfabrication of micro-electro-mechanical-system (MEMS) devices. However, they are constrained by the limitations of a conventional 320-nm photolithography process. Therefore, developing an ideal industrial i-line (365 nm) photolithography for Li 2 O–Al 2 O 3 –SiO 2 photosensitive glass-ceramics is urgently needed. This study initially explores the impact of a facile i-line photolithography on the structure and physicochemical properties of photosensitive glass ceramics. We experimentally showcase a direct, scalable, and straightforward i-line photolithography technique for Li 2 O–Al 2 O 3 –SiO 2 photosensitive glass ceramics. Our research concentrates on how the exposure time affects the properties of Li 2 O–Al 2 O 3 –SiO 2 photosensitive glass ceramics, particularly regarding nucleation and crystallization. This is achieved by adjusting the exposure time parameter and utilizing XRD, etching experiments, SEM, TEM, and other tests under a i-line light source. By optimizing the exposure process parameters, we also modify the annealing process parameters affecting the crystallization of lithium metasilicate in the exposed areas. Under a treatment process involving an exposure time of 20 min, a nucleation temperature of 500 °C, a crystallization temperature of 630 °C, and a nucleation/crystallization duration of 2 h, the sample achieves the highest crystal quantity and the optimal thickness-etching rate ratio. [ABSTRACT FROM AUTHOR]

In vivo electrochemistry in small brain regions or synapses requires nanoelectrodes with long straight tips for submicron scale measurements. Nanoelectrodes can be fabricated using a Nanoscribe two‐photon printer, but annealed tips curl if they are long and thin. We propose a new pulling‐force strategy to fabricate a straight carbon nanoneedle structure. A micron‐width bridge is printed between two blocks. The annealed structure shrinks during pyrolysis, and the blocks create a pulling force to form a long, thin, and straight carbon bridge. Parameterization study and COMSOL modeling indicate changes in the block size, bridge size and length affect the pulling force and bridge shrinkage. Electrodes were printed on niobium wires, insulated with aluminum oxide, and the bridge cut with focused ion beam (FIB) to expose the nanoneedle tip. Annealed needle diameters ranged from 400 nm to 5.25 μm and length varied from 50.5 μm to 146 μm. The electrochemical properties are similar to glassy carbon, with good performance for dopamine detection with fast‐scan cyclic voltammetry. Nanoelectrodes enable biological applications, such as dopamine detection in a specific Drosophila brain region. Long and thin nanoneedles are generally useful for other applications such as cellular sensing, drug delivery, or gas sensing. [ABSTRACT FROM AUTHOR]

The heavy use of toxic and volatile solvents such as dimethylformamide (DMF) and dimethylsulfoxide (DMSO), in the chemical synthesis of perovskites is known to pose several sustainability challenges that significantly hinder their mass production for commercial applications. Herein, a polymerizable monomer solvent (4‐acryloylmorpholine, ACMO) is introduced that permits the growth and optical lithography of perovskite quantum dots (PQDs) through in situ polymerization. Morphological, structural, and optical analyses show that this polymerizable monomer can act both as a solvent to dissolve the perovskite precursor and as a monomer for photopolymerization reactions, allowing direct in situ fabrication and patterning of PQDs. By direct photolithography, colorful PQD patterns with high photoluminescent quantum yields, high resolution (minimum size of 5 µm), and excellent fluorescence uniformity, are successfully demonstrated. The work provides a new sustainable way of in situ patterning PQDs using polymerizable monomer solvents, leading to significant advances in various integrated applications, such as photonic, energy harvesting, and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Conventional magnetophoresis techniques for manipulating biocarriers and cells predominantly rely on large‐scale electromagnetic systems, which is a major obstacle to the development of portable and miniaturized cell‐on‐chip platforms. Herein, a novel magnetic engineering approach by tailoring a nanoscale notch on a disk micromagnet using two‐step optical and thermal lithography is developed. Versatile manipulations are demonstrated, such as separation and trapping, of carriers and cells by mediating changes in the magnetic domain structure and discontinuous movement of magnetic energy wells around the circumferential edge of the micromagnet caused by a locally fabricated nano‐notch in a low magnetic field system. The motion of the magnetic energy well is regulated by the configuration of the nanoscale notch and the strength and frequency of the magnetic field, accompanying the jump motion of the carriers. The proposed concepts demonstrate that multiple carriers and cells can be manipulated and sorted using optimized nanoscale multi‐notch gates for a portable magnetophoretic system. This highlights the potential for developing cost‐effective point‐of‐care testing and lab‐on‐chip systems for various single‐cell‐level diagnoses and analyses. [ABSTRACT FROM AUTHOR]

Silicon nitride membranes were experimentally obtained as substrates for biological samples, which are examined using a microscope with an operating wavelength of 13.8 nm. The free-hanging films obtained have a size of up to 1.5 × 1.5 mm2, which makes it possible to select an area of interest for investigation on the sample on the order of tens to hundreds of microns. The mechanical strength of the membranes satisfies that the samples do not tear the membranes and withstand transportation. The results obtained are an import-substituting technology for the manufacture of Si3N4 membranes. The resulting membranes have a transparency of more than 40% in the range of the "water transparency window" (2.3–4.4 nm) and EUV (13–15 nm). The developed technology will become the basis for creating cuvettes for living biological samples for soft X-ray microscopy studies. [ABSTRACT FROM AUTHOR]

Colloidal quantum dots (QDs) are widely regarded as advanced emissive materials with significant potential for display applications owing to their excellent optical properties such as high color purity, near‐unity photoluminescence quantum yield, and size‐tunable emission color. Building upon these attractive attributes, QDs have successfully garnered attention in the display market as down‐conversion luminophores and now venturing into the realm of self‐emissive displays, exemplified by QD light‐emitting diodes (QD‐LEDs). However, despite these advancements, there remains a relatively limited body of research on QD patterning technologies, which are crucial prerequisites for the successful commercialization of QD‐LEDs. Thus, in this review, an overview of the current status and prospects of QD patterning technologies to accelerate the commercialization of QD‐LEDs is provided. Within this review, a comprehensive investigation of three prevailing patterning methods: optical lithography, transfer printing, and inkjet printing are conducted. Furthermore, several exploratory QD patterning techniques that offer distinct advantages are introduced. This study not only paves the way for successful commercialization but also extends the potential application of QD‐LEDs into uncharted frontiers. [ABSTRACT FROM AUTHOR]

Chemically amplified photoresists (CARs) are widely used in photolithography due to their excellent performance in resolution and sensitivity. This paper reports a CAR (SP8-PAGAN) based on molecule glass of SP8-Boc and photo-acid generator of N-hydroxytrifluoromethylsulfonate anthracene-1, 9-dicarboxyimide. The SP8-PAGAN photoresist can be used for both 365 nm lithography and electron beam lithography (EBL). The quantum efficiency of acid generation (ΦH+) for the PAGAN is 23% under 365 nm excitation. 1 μm positive and negative lithographic patterns can be achieved with SP8-PAGAN photoresist by 365 nm lithography using tetramethylammonium hydroxide (TMAH, 2. 38%) aqueous and n-hexane as developers, respectively. A positive 50 nm Line/Space (L/S) dense line pattern (dose 110 µC/cm²), a 32 nm L/S negative dense line pattern (dose 40 µC/cm²), and a 19 nm L/3S negative semi-dense line pattern (dose 96 µC/cm²) were achieved by EBL. This study provides a new example of a dual-tone CAR for multi-purpose lithography. [ABSTRACT FROM AUTHOR]

This paper provides an overview of state-of-the-art sensing and machine learning technologies for intelligent measurement in smart and precision manufacturing. Length, angle, and force are identified as the fundamental quantities for production quality management based on process monitoring as well as geometrical metrology in optical lithography and mechanical machining. Advancements in length-based measurement technologies such as laser interferometers and optical encoders, as well as advancements regarding depth and thickness measurements, are presented. Various types of optical microscopes, such as evanescent field microscopes, structured illumination microscopes, and confocal microscopes, are also described. For angle-based measurement technologies, in addition to the conventional continuous-wave laser autocollimators, the newly developed Fabry–Pérot angle sensor and nonlinear optics angle sensor using an ultrashort pulse laser are presented. Finally, on-machine and in-process force sensing and machining learning techniques for dimensional and machining process monitoring are reviewed. [ABSTRACT FROM AUTHOR]

Retroreflectors are an important optical component, but current retroreflector structures and manufacturing processes are relatively complex. This paper proposes a rapid, low-cost, large-area method for fabricating retroreflectors based on microlens arrays. Tunable microlens arrays with adjustable curvature, fill factor, and sizes were prepared using photolithography and thermal reflow techniques. Subsequently, a two-step nanoimprinting process was used to create a flexible reverse mold and transfer the structure onto the desired substrate. The microlens arrays, with a diameter of 30 μm, a period of 33 μm, a curvature radius ranging from 15.5 to 18.8 μm, and a fill factor ranging from 75.1% to 88.8%, were fabricated this way. In addition, the method also fabricated microlens arrays with diameters ranging from 10 to 80 μm. Retroreflectors were made by sputtering a layer of silver on the MLAs as a reflecting layer, and tests showed that the microlens-based retroreflector exhibited superior retroreflective performance with a wide-angle response of ±75°. Microlens-based retroreflectors have the advantages of simple operation and controllable profiles. The fabrication method in this paper is suitable for large-scale production, providing a new approach to retroreflector design. [ABSTRACT FROM AUTHOR]

Photolithography with visible light at λ = 405 nm utilizing the concept of nonlinear saturable absorption effect where the size of the spot is diminished to the nanometer scale as proposed by several researchers is an alluring proposition for cost-effective projection lithography. Costly conventional condenser lenses can be replaced by monochromatic aberration-free and cost-effective volume phase holographic lenses for visible light photolithography with enhanced resolution utilizing the concept of off-axis illumination. However, the diffraction efficiency of holographic lenses depends on the wavelength of illuminating light and the angle of illumination. Angular and spectral characteristics of volume phase holograms can be controlled by optimizing processing parameters. The results on the theoretical optimization of three important processing parameters, namely fringe spacing ( $ \wedge $ ∧), thickness of the film ( $ d $ d), and refractive index modulation ( $ \Delta n $ Δn) in the light of coupled wave theory for recording holographic lenses of high diffraction efficiency at $ \lambda = 405 \,\textrm{nm} $ λ=405nm are presented. It is pointed out that a properly designed single holographic lens can be used for off-axis illumination of a photomask with a parallel beam of light, whereas a system of two identical holographic lenses cemented together has to be used to realize a condenser lens similar to a converging lens. [ABSTRACT FROM AUTHOR]

Spatially controllable focal fields play a pivotal role in light manipulation and provide significant opportunities for precisely manipulating light–matter interactions in a wide range of applications. In particular, the double-helix focal field—characterized by a distinctive helical structure—exhibits exceptional optical properties, thus differentiating it apart from conventional focal fields. However, the rapid construction of a double-helix focal field with controllable characteristics and a uniform intensity remains a challenging task. Based on the theory of pattern synthesis of an antenna array, we propose and realize the generation of three-dimensional doughnut-spot arrays and double-helix focal fields with specified characteristics in a 4 π system by reverse-solving the radiation field of the virtual antenna. Numerical examples indicate that the desired novel focal fields, including features such as shape, orientation, length, and period, could be rapidly, conveniently, and flexibly customized by selecting appropriate parameters for the magnetic dipole array antennas. This method could reveal an avenue for enhanced light manipulation for applications in materials processing, optical lithography, and optical communications. [ABSTRACT FROM AUTHOR]

Recent years have witnessed a surge in the application of microrobots within the medical sector, with hydrogel microrobots standing out due to their distinctive advantages. These microrobots, characterized by their exceptional biocompatibility, adjustable physico-mechanical attributes, and acute sensitivity to biological environments, have emerged as pivotal tools in advancing medical applications such as targeted drug delivery, wound healing enhancement, bio-imaging, and precise surgical interventions. The capability of hydrogel microrobots to navigate and perform tasks within complex biological systems significantly enhances the precision, efficiency, and safety of therapeutic procedures. Firstly, this paper delves into the material classification and properties of hydrogel microrobots and compares the advantages of different hydrogel materials. Furthermore, it offers a comprehensive review of the principal categories and recent innovations in the synthesis, actuation mechanisms, and biomedical application of hydrogel-based microrobots. Finally, the manuscript identifies prevailing obstacles and future directions in hydrogel microrobot research, aiming to furnish insights that could propel advancements in this field. [ABSTRACT FROM AUTHOR]

This paper presents the line-edge-roughness (LER) characterization of the photomask patterns and the lithography-printed patterns by enhanced knife edge interferometry (EKEI) that measures the interferometric fringe patterns occurring when the light is incident on the patterned edge. The LER is defined as a geometric deviation of a feature edge from an ideal sharp edge. The Fresnel number-based computational model was developed to simulate the fringe patterns according to the LER conditions. Based on the computational model, the photomask patterns containing LER features were designed and fabricated. Also, the patterns were printed on the glass wafer by photolithography. The interferometric fringe patterns of those two groups of patterns were measured and compared with the simulation results. By using the cross-correlation method, the LER effects on the fringe patterns were characterized. The simulation and experimental results showed good agreement. It showed that the amplitude of the fringe pattern decreases as the LER increases in both cases: photomask patterns and printed wafer patterns. As a result, the EKEI and its analysis methods showed the potential to be used in photomask design and pattern metrology, and inspection for advancing semiconductor manufacturing processes. • The line-edge-roughness (LER) of the photomask patterns and the lithography-printed patterns was characterized by enhanced knife edge interferometry (EKEI). • The Fresnel number-based computational model was developed to simulate the fringe patterns according to the LER conditions. • The fringe patterns obtained by EKEI were analyzed by the cross-correlation method. As a result, the similarity value decreased as the LER increased. • The EKEI and its analysis methods showed the potential to be utilized in photomask design and pattern metrology and inspection for advancing semiconductor manufacturing processes. [ABSTRACT FROM AUTHOR]

Photoresists are fundamental materials in photolithography and are crucial for precise patterning in microelectronic devices, MEMS, and nanostructures. This paper provides an in-depth review of recent advancements in positive photoresist research and development, focusing on discussion regarding the underlying mechanisms governing their behavior, exploring innovative fabrication techniques, and highlighting the advantages of the photoresist classes discussed. The paper begins by discussing the need for the development of new photoresist technologies, highlighting issues associated with adopting extreme ultraviolet photolithography and addressing these challenges through the development of advanced positive-tone resist materials with improved patterning features, resolution, and sensitivity. Subsequently, it discusses the working mechanisms and synthesis methods of different types and subtypes of photoresists, starting from non-chemically amplified, organic, and inorganic–organic hybrid photoresists and progressing to dry film resists, with an emphasis on the upsides of each. The paper concludes by discussing how future research in the field of lithography—prioritizing concerns related to environmental impacts, improved photoresist material and properties, and utilization of advanced quantum technology—can assist with revolutionizing lithography techniques. [ABSTRACT FROM AUTHOR]

Controlling overlay in lithography is crucial for improving the yield of integrated circuit manufacturing. The process disturbances can cause undesirable morphology changes of overlay targets (such as asymmetric grating), which can significantly impact the accuracy of overlay metrology. It is essential to decouple the overlay target asymmetry from the wafer deformation, ensuring that the overlay metrology is free from the influence of process-induced asymmetry (e.g., grating asymmetry and grating imbalance). Herein, we use an asymmetric grating as a model and show that using high-diffraction-order light can mitigate the impact of asymmetric grating through the rigorous coupled-wave analysis (RCWA) method. In addition, we demonstrate the diffraction efficiency as a function of the diffraction order, wavelength, and pitch, which has guiding significance for improving the measurement accuracy of diffraction-based overlay (DBO) metrology. [ABSTRACT FROM AUTHOR]

A configurable design of a microstrip square spiral RFID tag antenna, for a wide range of microwave frequencies in the S- and C-band, is presented. The design is parameterized in dimensions, and hence changing the design frequency (or frequencies) is easy, by changing only an initial value for the spiral geometry. A tag specimen was fabricated using a Cu electroplating technique according to the design for frequencies of interest in the areas of 2.4 and 5.8 GHz. The substrate material is 320 μm high-resistivity Si and the bridge dielectric is 15 μm polyimide PI2525. The steps of the microfabrication process involve metallic structure pattern transfer techniques with optical UV lithography procedures. The reflection coefficient and antenna gain of the specimen were measured inside an anechoic enclosure using a vector network analyzer (VNA) and a TEM horn test antenna over a frequency range of up to 6 GHz. Simulated and measured results, exhibiting reasonable agreement, are presented and discussed. [ABSTRACT FROM AUTHOR]

Micropipette aspiration (MPA) is one of the gold standards for quantifying biological samples' mechanical properties, which are crucial from the cell membrane scale to the multicellular tissue. However, relying on the manipulation of individual home-made glass pipettes, MPA suffers from low throughput and no automation. Here, we introduce the sliding insert micropipette aspiration method, which permits parallelization and automation, thanks to the insertion of tubular pipettes, obtained by photolithography, within microfluidic channels. We show its application both at the lipid bilayer level, by probing vesicles to measure membrane bending and stretching moduli, and at the tissue level by quantifying the viscoelasticity of 3D cell aggregates. This approach opens the way to high-throughput, quantitative mechanical testing of many types of biological samples, from vesicles and individual cells to cell aggregates and explants, under dynamic physico-chemical stimuli. [ABSTRACT FROM AUTHOR]

This study compares the capital and operating costs of RGB OLED notebook panels patterned by conventional FMM to an alternative photolithographic approach. The results are used to analyze the benefits and challenges of each technology and how those may influence the rapidly growing OLED IT panel market. [ABSTRACT FROM AUTHOR]

We achieved a high‐luminance and highly reliable tandem organic light‐emitting diode (OLED) designed for photolithography applications by developing a new intermediate connector with resistance to water and atmospheric elements. We succeeded in fabricating a side‐by‐side (SBS) tandem OLED display by our SBS pixel‐patterning method involving organic layer etching via photolithography. [ABSTRACT FROM AUTHOR]

ViPTM (Visionox intelligent Pixelization) Technology is a novel RGB self‐aligned pixelization approach without Fine Metal Mask for OLED patterning. Since being released in May 2023, numerous breakthrough technical progress has been achieved. In this presentation, the recent results on panel performance and other advantages of ViPTM Technology will be discussed. [ABSTRACT FROM AUTHOR]

In this work, efficient QD‐photosensitive ligand system were designed. By direct photolithography, RGB pixel arrays with a single sub‐pixel size of 39 um × 5 um were successfully prepared on patterned PM substrates. While illuminated separately, there were no residual QD emission peaks from neighbor sub‐pixel in electroluminescence spectra. Experience on the PM substrate guided the successful preparation of a 4.7‐inch 650 ppi AM‐QLED display. This was the first AM‐QLED prototype prepared by direct lithography. [ABSTRACT FROM AUTHOR]

With the advancement of manufacturing equipment and the development of sensing technology, the measurement cycle of data is becoming very short, and the characteristics of data observed at the same time are also diversifying. A Fault Detection and Classification (FDC) system is in operation to collect and analyze measurement data in real time in the display manufacturing factory. However, the anomaly detection function provided by the FDC system is based on a threshold comparison method for data in seconds, so there is a limit to accuracy in processing measurement data in milliseconds. In particular, if the process for one panel is divided into several steps and each of them shows various characteristics, it is difficult to manage because it takes a lot of airlift to set search conditions and thresholds for anomaly detection. To overcome this, a waveform analysis system is implemented to assist the FDC system. This system extracts waveforms from milliseconds of measurement data during the processing time of one panel in the equipment, and diagnoses whether the equipment processing is normal through GAN‐based waveform pattern analysis. Generative models are used in the anomaly detection process in consideration of the manufacturing environment in which the normal data is overwhelmingly larger than the abnormal data. The DCGAN‐based model that is excellent in image processing and the TadGAN‐based model that combines Auto encoder and GAN were implemented and used. In this paper, the anomaly detection performance of models is compared and evaluated for the display photo process Coater Pressure sensor using the waveform analysis system implemented in this way. [ABSTRACT FROM AUTHOR]

In mass manufacturing of OLED displays, photolithography process is a critical bottleneck in production capacity. As a result, effective scheduling of the photolithography process is crucial to the overall throughput, productivity, and efficiency of the production. The processing of OLED panels depends upon heterogeneous resources. Aside from that, the complexity, stochastic nature, and highly dynamic characteristic of the processpresent considerable challenges. To address these, we propose a new framework employing a heterogeneous graph neural networkbased Rainbow algorithm. This framework optimizes the schedule used in photolithography process. Considering the constraints on machines, masks, and the stochastic nature of arrival processes, we optimize for maximizing productivity while minimizing the associated costs. We model the interactions among product lot steps, machines, and masks as a heterogeneous graph. This graph encodes the information of lot steps, machines, and masks into distinctive nodes. We then implement a Graph Attention Networkbased architecture for deep representation learning. This transforms state information into node embeddings for each step of each product lot, facilitating decision‐making. Reinforcement learning agents leverage these embeddings to prioritize products via a parameterized Q‐function. Our extensive experiments demonstrate the superior performance of our approach across multiple evaluation metrics in both static and dynamic environment benchmarks, with a higher winning rate and scheduling reward return when compared to existing reinforcement learning methods. [ABSTRACT FROM AUTHOR]

We report a photolithography‐based technology for patterning quantum dot color converters for micro‐LED displays. A patterning resolution of ~1 µm is achieved. The method can be applied to any color converter materials. Integration of perovskite quantum dots and CdSe/ZnS quantum dots is demonstrated to show the versatility of the technology. [ABSTRACT FROM AUTHOR]

This study presents the fabrication of a 513‐ppi organic light‐emitting diode (OLED) display featuring an integrated organic photodiode (OPD) within each pixel, eliminating the need for a fine metal mask. The fabrication process involves photolithography for the side‐by‐side patterning of OLED and OPD subpixels, leading to a four‐subpixel configuration. This configuration incorporates an OPD subpixel into each pixel while preserving the high resolution of OLED subpixels. The outcome is the successful development of an active panel capable of both high‐resolution display and imaging, boasting a high aperture ratio. [ABSTRACT FROM AUTHOR]