Micro and nanofabrication technologies are integral to the development of miniaturized systems. Lithography plays a key role in micro and nanofabrication techniques. Since high functional ...miniaturized systems are required in various fields, such as the development of a semiconductor, chemical and biological analysis, and biomedical researches, lithography techniques have been developed and applied for their appropriate purpose. Lithography can be classified into conventional and unconventional lithography, or top-down and bottom-up, or with mask and mask-less approaches. In this chapter, various lithography techniques are categorized and classified into conventional and unconventional lithography. In the first part, photolithography, electron beam, and focused-ion beam lithography are introduced as conventional lithography techniques. The second part introduces nanoimprint lithography, deformation lithography, and colloidal lithography as unconventional lithography techniques. In the last part, the pros and cons of each lithography are discussed for an appropriate design of fabrication processes.
An antireflection coating was created for InP-based pin photodiodes using natural lithography with 100 nm-diameter SiO^sub 2^ spheres. The surface showed a normal-incidence reflection of <5% for ...wavelengths from 900 to 2500 nm. Photodiodes with surface texturing showed an enhancement in quantum efficiency with no dark current degradation. PUBLICATION ABSTRACT
For all technologies, from flint arrowheads to DNA microarrays, patterning the functional material is crucial. For semiconductor integrated circuits (ICs), it is even more critical than for most ...technologies because enormous benefits accrue to going smaller, notably higher speed and much less energy consumed per computing function. The consensus is that ICs will continue to be manufactured until at least the ldquo22 nm noderdquo (the linewidth of an equal line-space pattern). Most patterning of ICs takes place on the wafer in two steps: (a) lithography, the patterning of a resist film on top of the functional material; and (b) transferring the resist pattern into the functional material, usually by etching. Here we concentrate on lithography. Optics has continued to be the chosen lithographic route despite its continually forecast demise. A combination of 193-nm radiation, immersion optics, and computer-intensive resolution enhancement technology will probably be used for the 45- and 32-nm nodes. Optical lithography usually requires that we first make a mask and then project the mask pattern onto a resist-coated wafer. Making a qualified mask, although originally dismissed as a ldquosupport technology,rdquo now represents a significant fraction of the total cost of patterning an IC largely because of the measures needed to push resolution so far beyond the normal limit of optical resolution. Thus, although optics has demonstrated features well below 22 nm, it is not clear that optics will be the most economical in this range; nanometer-scale mechanical printing is a strong contender, extreme ultraviolet is still the official front runner, and electron beam lithography, which has demonstrated minimum features less than 10 nm wide, continues to be developed both for mask making and for directly writing on the wafer (also known as ldquomaskless lithographyrdquo). Going from laboratory demonstration to manufacturing technology is enormously expensive ( 1 billion) and for good reason. Just in terms of data rate (mask pattern to resist pattern), today's exposure tools achieve about 10 Tb/s at an allowable error rate of about 1/h; this data rate will double with each generation. In addition, the edge placement precision required will soon be 30 parts per billion. There are so many opportunities for unacceptable performance that making the right decision goes far beyond understanding the underlying physical principles. But the benefits of continuing to be able to manufacture electronics at the 22-nm node and beyond appear to justify the investment, and there is no shortage of ideas on how to accomplish this.
The semiconductor industry has long been driven by advances in a nanofabrication technology known as lithography, and the fabrication of nanostructures on chips relies on an important coating, the ...photoresist layer. Photoresists are typically spin-coated to form a film and have a photolysis solubility transition and etch resistance that allow for rapid fabrication of nanostructures. As a result, photoresists have attracted great interest in both fundamental research and industrial applications. Currently, the semiconductor industry has entered the era of extreme ultraviolet lithography (EUVL) and expects photoresists to be able to fabricate sub-10 nm structures. In order to realize sub-10 nm nanofabrication, the development of photoresists faces several challenges in terms of sensitivity, etch resistance, and molecular size. In this paper, three types of lithographic mechanisms are reviewed to provide strategies for designing photoresists that can enable high-resolution nanofabrication. The discussion of the current state of the art in optical lithography is presented in depth. Practical applications of photoresists and related recent advances are summarized. Finally, the current achievements and remaining issues of photoresists are discussed and future research directions are envisioned.
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•The development of photolithography and photoresists is reviewed.•Lithography materials with the potential to create sub-10 nm nanostructures are highlighted, including CARs, MOCs and main-chain scission materials.•The realization of advanced lithographic materials applied to some promising nanofabrication areas is summarized.
Abstract
Lithography is one of the key technologies that restrict the development of the semiconductor industry and its important role continues to be highlighted. This paper will review laser ...projection lithography and laser maskless lithography based on the theoretical knowledge of laser lithography, present the advantages of laser maskless lithography, discuss the latest progress of laser lithography in application fields, explore its development prospects and trends, and provide some ideas and inspiration for the further development of human laser lithography. The result shows that laser lithography can be used in the field of material processing, and lithography is one of the key technologies to fabricate semiconductor devices. The world’s most advanced lithography machine is the EUV lithography machine of the Dutch ASML. This EUV lithography machine can be used for the production of 5nm chips, so 5nm is the most advanced chip manufacturing process that EUV lithography machine can achieve. Since lithography is a high degree of composite technology, each component plays an irreplaceable role. Therefore, if further improvements are to be made to the chip process, researchers should look at all parts of the exposure system, photoresist and process technology to make them work together in harmony.
Here, the hydrogen evolution reaction (HER) activities at the edge and basal‐plane sites of monolayer molybdenum disulfide (MoS2) synthesized by chemical vapor deposition (CVD) are studied using a ...local probe method enabled by selected‐area lithography. Reaction windows are opened by e‐beam lithography at sites of interest on poly(methyl methacrylate) (PMMA)‐covered monolayer MoS2 triangles. The HER properties of MoS2 edge sites are obtained by subtraction of the activity of the basal‐plane sites from results containing both basal‐plane and edge sites. The catalytic performances in terms of turnover frequencies (TOFs) are calculated based on the estimated number of active sites on the selected areas. The TOFs follow a descending order of 3.8 ± 1.6, 1.6 ± 1.2, 0.008 ± 0.002, and 1.9 ± 0.8 × 10−4 s−1, found for 1T′‐, 2H‐MoS2 edges, and 1T′‐, 2H‐MoS2 basal planes, respectively. Edge sites of both 2H‐ and 1T′‐MoS2 are proved to have comparable activities to platinum (≈1–10 s−1). When fitted into the HER volcano plot, the MoS2 active sites follow a trend distinct from conventional metals, implying a possible difference in the reaction mechanism between transition‐metal dichalcogenides (TMDs) and metal catalysts.
Utilizing an on‐chip electrochemical device, which is capable of measuring the hydrogen‐evolution performance on the designated location of monolayer MoS2, the catalytic activities of the basal‐plane and edge sites of both 2H and 1T′‐MoS2 are identified. The activities of the MoS2 active sites follow a unique trend in the volcano plot.
Optical metasurfacespatterned arrays of plasmonic nanoantennas that enable the precise manipulation of light–matter interactionsare emerging as critical components in many nanophotonic materials, ...including planar metamaterials, chemical and biological sensors, and photovoltaics. The development of these materials has been slowed by the difficulty of efficiently fabricating patterns with the required combinations of intricate nanoscale structure, high areal density, and/or heterogeneous composition. One convenient strategy that enables parallel fabrication of periodic nanopatterns uses self-assembled colloidal monolayers as shadow masks; this method has, however, not been extended beyond a small set of simple patterns and, thus, has remained incompatible with the broad design requirements of metasurfaces. This paper demonstrates a techniqueshadow-sphere lithography (SSL)that uses sequential deposition from multiple angles through plasma-etched microspheres to expand the variety and complexity of structures accessible by colloidal masks. SSL harnesses the entire, relatively unexplored, space of shadow-derived shapes andwith custom software to guide multiangled depositioncontains sufficient degrees of freedom to (i) design and fabricate a wide variety of metasurfaces that incorporate complex structures with small feature sizes and multiple materials and (ii) generate, in parallel, thousands of variations of structures for high-throughput screening of new patterns that may yield unexpected optical spectra. This generalized approach to engineering shadows of spheres provides a new strategy for efficient prototyping and discovery of periodic metasurfaces.
Platinum (Pt) is an interesting material for many applications due to its high chemical resilience, outstanding catalytic activity, high electrical conductivity, and high melting point. However, ...microstructuring and especially 3D microstructuring of platinum is a complex process, based on expensive and specialized equipment often suffering from very slow processing speeds. In this work, organic–inorganic photoresins, which can be structured using direct optical lithography as well as two‐photon lithography (TPL) with submicrometer resolution and high‐throughput is presented. The printed structures are subsequently converted to high‐purity platinum using thermal debinding of the binder and reduction of the salt. With this technique, complex 3D structures with a 3D resolution of 300 nm were fabricated. At a layer thickness of 35 nm, the patterns reach a high conductivity of 67% compared to bulk platinum. Microheaters, thermocouple sensors as well as a Lab‐on‐a‐Chip system are presented as exemplary applications. This technology will enable a broad range of application from electronics, sensing and heating elements to 3D photonics and metamaterials.
High‐resolution patterning of an organic–inorganic platinum containing photoresin by microlithography and two‐photon polymerization is demonstrated. The polymerized microstructures are debinded and reduced to highly conductive metallic platinum at a resolution of 300 nm. The conductivity of the reduced platinum structures is 67% of the conductivity of bulk platinum.
Dip‐pen nanolithography (DPN) is a unique nanofabrication tool that can directly write a variety of molecular patterns on a surface with high resolution and excellent registration. Over the past 20 ...years, DPN has experienced a tremendous evolution in terms of applicable inks, a remarkable improvement in fabrication throughput, and the development of various derivative technologies. Among these developments, polymer pen lithography (PPL) is the most prominent one that provides a large‐scale, high‐throughput, low‐cost tool for nanofabrication, which significantly extends DPN and beyond. These developments not only expand the scope of the wide field of scanning probe lithography, but also enable DPN and PPL as general approaches for the fabrication or study of nanostructures and nanomaterials. In this review, a focused summary and historical perspective of the technological development of DPN and its derivatives, with a focus on PPL, in one timeline, are provided and future opportunities for technological exploration in this field are proposed.
Dip‐pen nanolithography (DPN) is a unique nanofabrication tool that can directly write a variety of molecular patterns on a surface with high resolution and excellent registration using a scanning tip. DPN has experienced a tremendous evolution since its invention in 1999. This work reviews the technical development of DPN and its derivative technologies over the past 20 years.
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