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Micropatterning is a powerful method for controlling surface properties, with applications from cell biology to electronics 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 . Self-assembled monolayers (SAMs) of alkanethiolates on gold and silver 9 , 10 , 11 —the structures most widely used for preparing organic films with specific surface properties—are usually patterned by partitioning the surface into regions formed from different thiols 12 , 13 , 14 , 15 . Here we describe a way to pattern SAMs using a single alkanethiol on substrates consisting of regions of different topography: planar islands of one metal on the surface of a second (which may be different from or the same as the first). These topographically patterned SAMs consist of three regions: two planar surfaces and a transition region between the two. The characters of the SAMs on these three regions were inferred from images of three structures that form on them: condensation figures, patterns of crystals of CaCO 3 and regions of selective etching. The transition region is more active in the processes generating these structures than either of the two planar regions, and we propose that this activity is due to the relatively high disorder in the organic film there. We believe that this ability to control the local disorder in a SAM with high resolution will be important in controlling processes such as nucleation, wetting, adhesion and etching on scales of below 50 nm to 5 µm.

Nanostructured surfaces with quasi-random geometries can manipulate light over broadband wavelengths and wide ranges of angles. Optimization and realization of stochastic patterns have typically relied on serial, direct-write fabrication methods combined with real-space design. However, this approach is not suitable for customizable features or scalable nanomanufacturing. Moreover, trial-and-error processing cannot guarantee fabrication feasibility because processing–structure relations are not included in conventional designs. Here, we report wrinkle lithography integrated with concurrent design to produce quasi-random nanostructures in amorphous silicon at wafer scales that achieved over 160% light absorption enhancement from 800 to 1,200 nm. The quasi-periodicity of patterns, materials filling ratio, and feature depths could be independently controlled. We statistically represented the quasi-random patterns by Fourier spectral density functions (SDFs) that could bridge the processing–structure and structure–performance relations. Iterative search of the optimal structure via the SDF representation enabled concurrent design of nanostructures and processing.

In the milling process of metallic parts, appropriate tool conditions are essential to reducing processing faults and ensuring manufacturing quality. However, the existing condition monitoring methods are usually limited by recognizing intermediate abnormal states during milling processing, which is inefficient and impractical for real practical applications. Therefore, this paper proposes a tool condition monitoring (TCM) method in the milling process based on multisource pattern recognition and state transfer paths. First, the improved K-means clustering method is used to generate multiple patterns of tool wear. Second, a multisource pattern recognition model framework is developed, and multiple observation windows and the pattern transfer path are considered in the multisource pattern recognition model. Finally, PHM2010 datasets are used to verify the feasibility of the proposed method, and the results demonstrate the applicability of the proposed method in practice for tool condition monitoring.

To meet the increasing demand for patterning smaller feature sizes, a lithography technique is required with the ability to pattern sub-20 nm features. While top-down photolithography is approaching its limit in the continued drive to meet Moore's law, the use of directed self-assembly (DSA) of block copolymers (BCPs) offers a promising route to meet this challenge in achieving nanometre feature sizes. Recent developments in BCP lithography and in the DSA of BCPs are reviewed. While tremendous advances have been made in this field, there are still hurdles that need to be overcome to realize the full potential of BCPs and their actual use.

•Bloodstain pattern analysis is a field of forensic science, and the need for experiments and education is emphasized for bloodstain analyst.•Through the development of appropriate blood substitute that can replace human blood, it can greatly help in the development of forensic science and bloodstain pattern analysis.•In the manufacture of blood substitute, the similarity between physical properties and drip bloodstain characteristics with human blood is very important.•It will be more efficient if various functions are complemented for practical use of blood substitute. Bloodstain pattern analysis, one of the areas of forensic science, is performed to analyze the physical characteristics of bloodstains, including their size, shape, and distribution, to reconstruct a crime scene. A bloodstain pattern analyst should obtain through experiments and education the capabilities to both understand the generation mechanisms of bloodstains and identify the characteristics of the bloodstains. Experiments and education about bloodstain pattern analysis are carried out by using human blood taken from subjects, animal blood (porcine or bovine) supplied from butcheries, and blood substitute products developed in other countries. However, these kinds of blood have many limitations in their application due to various problems. The blood substitute developed in the present study is more similar to human blood than other blood substitute products developed in other countries with regard to the physical properties, including viscosity, viscoelasticity, and surface tension, as well as the drip bloodstain patterns depending on the surface and coordinate characteristics of drip stains impact angle. The blood substitute developed in the present study is more practical, because the materials that are used in its preparation are readily available in the market and do not include chemicals that are harmful to the human body, and the blood substitute has luminol reaction functionality and pattern transfer bloodstain (bloodstain fingerprint, bloodstain footprint, etc.) dyeing functionality.

A simple, versatile approach to the directed self-assembly of block copolymers into a macroscopic array of unidirectionally aligned cylindrical microdomains on reconstructed faceted single crystal surfaces or on flexible, inexpensive polymeric replicas was discovered. High fidelity transfer of the line pattern generated from the microdomains to a master mold is also shown. A single-grained line patterns over arbitrarily large surface areas without the use of top-down techniques is demonstrated, which has an order parameter typically in excess of 0.97 and a slope error of 1.1 deg. This degree of perfection, produced in a short time period, has yet to be achieved by any other methods. The exceptional alignment arises from entropic penalties of chain packing in the facets coupled with the bending modulus of the cylindrical microdomains. This is shown, theoretically, to be the lowest energy state. The atomic crystalline ordering of the substrate is transferred, over multiple length scales, to the block copolymer microdomains, opening avenues to large-scale roll-to-roll type and nanoimprint processing of perfectly patterned surfaces and as templates and scaffolds for magnetic storage media, polarizing devices, and nanowire arrays.

This letter solves a major hurdle that mars photolithography-based fabrication of micro-mesoscale structures in silicon. Conventional photolithography is usually performed on smooth, flat wafer surfaces to lay a 2D design and subsequently etch it to create single-level features. It is, however, unable to process non-flat surfaces or already etched wafers and create more than one level in the structure. In this study, we have described a novel cleanroom-based process flow that allows for easy creation of such multi-level, hierarchical 3D structures in a substrate. This is achieved by introducing an ultra-thin sacrificial silicon dioxide hardmask layer on the substrate which is first 3D patterned via multiple rounds of lithography. This 3D pattern is then scaled vertically by a factor of 200–300 and transferred to the substrate underneath via a single shot deep etching step. The proposed method is also easily characterizable—using features of different topographies and dimensions, the etch rates and selectivities were quantified; this characterization information was later used while fabricating specific target structures. Furthermore, this study comprehensively compares the novel pattern transfer technique to already existing methods of creating multi-level structures, like grayscale lithography and chip stacking. The proposed process was found to be cheaper, faster, and easier to standardize compared to other methods—this made the overall process more reliable and repeatable. We hope it will encourage more research into hybrid structures that hold the key to dramatic performance improvements in several micro-mesoscale devices.

Lithography is a key enabling technique in modern micro/nano scale technology. Achieving the optimal trade-off between resolution, throughput, and cost remains a central focus in the ongoing development. However, current lithographic techniques such as direct-write, projection, and extreme ultraviolet lithography achieve higher resolution at the expense of increased complexity in optical systems or the use of shorter-wavelength light sources, thus raising the overall cost of production. Here, we present a cost-effective and wafer-level perfect conformal contact lithography at the diffraction limit. By leveraging a transferable photoresist, the technique ensures optimal contact between the mask and photoresist with zero-gap, facilitating the transfer of patterns at the diffraction limit while maintaining high fidelity and uniformity across large wafers. This technique applies to a wide range of complex surfaces, including non-conductive glass surfaces, flexible substrates, and curved surfaces. The proposed technique expands the potential of contact photolithography for novel device architectures and practical manufacturing processes. Mainstream lithography techniques struggle to balance high resolution, large-area patterning, and low cost. Perfect conformal contact lithography enables sub-wavelength resolution patterning. Achieving large-area, zero-gap conformal contact between the transferable photoresist and the mask is essential. Large-aperture metalens fabricated via perfect conformal contact lithography enable clear infrared imaging over extended distances. Perfect conformal contact lithography is promising for high-performance fabrication in emerging areas such as flexible electronics and micro/nano-optical devices.

This paper presents the manufacturing procedure and electrical properties of a microstrip line on flexible printed circuit boards (FPCBs) fabricated using the micro pattern transfer printing (MPTP) method for millimeter wave band application. The MPTP method presented herein is compared to the conventional FPCB process based on the degree of insertion loss as it pertains to the cross-sectional shape of the formed microstrip line. Electromagnetic field simulations were performed to confirm that the cross-sectional arch shape fabricated by the MPTP process reduces insertion loss in the high-frequency band. Based on the simulation, the microstrip transmission line was optimized to a width of 217 µm and a length of 30 cm, fabricated on a 50 µm thick poly-cyclohexylene dimethylene terephthalate (PCT) substrate to measure the insertion loss. The insertion loss fabricated using the MPTP method is measured as 0.37 dB/cm at 10 GHz, while the conventional FPCB is measured as 0.66 dB/cm. Through the analysis, it was confirmed that the FPCBs manufactured by the MPTP process show lower insertion loss compared to the conventional FPCBs.

As metal-containing resists attract increasing research interest in high-resolution lithography, gaining insights into the photochemical mechanisms, particularly in relation to the ligand functionality, is actively demanded. In this work, a controlled pair of organotin carboxylates with analogous structures but different functional groups has been designed and synthesized as deep-ultraviolet (DUV) resists. Both resists demonstrate 90 nm half-pitch resolution and the capability of pattern transfer on carbon-based hard-mask layers. Through various characterizations and comparison of the controlled pair, we propose two competitive reaction paths for the organotin system with olefin groups, which regulate the lithographic sensitivity and dissolution contrast. Our findings highlight the structural adjustability of organotin carboxylates and their potential application as high-resolution and etch-durable DUV resists.