Water‐Based Photo‐ and Electron‐Beam Lithography Using Egg White as a Resist

Abstract

human life. [1][2][3] To achieve such a dream, choosing natural biomaterials such as nucleic acids, [4][5][6] peptides, [7] proteins, [8,9] and polysaccharides [10] as the substitutes of fossil source-based synthetic chemicals is a promising way. Correspondingly, micro/ nanoscale fabrication on natural biomaterials receives great of importance, [11] and a spatially definable property with high precision to exactly position biomaterials on a surface is highly desirable [12][13][14][15][16][17][18] toward biodegradable and biocompatible green electronic, [19][20][21][22] optical, [23][24][25][26][27][28][29] sensor, [30] energy, [31] and environmental devices. [32] Typical examples down this road include silk fibroin, [12][13][14] polysaccharides, [10] and DNA origami-mediated lithography. [5] These approaches are part of great efforts to develop "green" lithographic processing in semiconductor industry that is eligible to lessen the exposure of workers and environment toward noxious chemical and reduce waste. [13] The adoption of these strategies allows the replacement of organic solvent with water to cast and develop a resist, accompanied with the exclusion of environmentally harmful components from material processing and fabrication. However, so far the lithographic processes based on existing natural biomaterials are difficult to be exploited in scale-up industrial application, because their limited quantities, high material, and processing cost as well as small deposition area impede the practical engineering of these biomaterials. [9] Moreover, the less-controlled variation on polymorph and polydispersity of biomaterials often influences the repeatability of results. [33] Recently, our group reported the use of phase-transited lysozyme nanofilm as the resist for photolithography and electron-beam lithography (EBL), with the cost being decreased and practical applicability being potentially demonstrated. [17] Continuous efforts along this way further require much cheaper material and simpler fabrication process for large-scale industrial uses. In this respect, we pay attention to egg white due to the following reasons. First, egg white is a very common natural biomaterial just taken from egg as our daily food, which makes it has great natural abundance with a low cost. Second, in contrast to other natural competitors usually requiring strict demands on the purity, polydispersity, and polymorph stability, egg white is a combination of multiple functional nutrients, [34] which could be directly utilized without further purification and Complex lithographic steps and the use of toxic chemicals in these processes are in conflict with a sustainable human society. Development of new inexpensive and green resist, simple alternative procedures, and nontoxic solvents is the key to move recyclable micro/nanofabrication from laboratory level to industrial application in large scale. Herein, precise control on protein fragmentation/aggregation upon photo/electron irradiation is conceived into egg white-based green resist...

An insight on egg white: From most common functional food to biomaterial application

“…Under low‐irradiation doses (3,000 and 1,500 μC/cm), photolithography and electron beam direct writing on spin‐coated egg white layers can produce effective complex micro‐ and nanopatterns (Figure 3). 80 …”

CO2‐Based Dual‐Tone Resists for Electron Beam Lithography

“…Furthermore, these nanofabrication processes require an ultralow operating temperature, including a specially designed heating/cooling stage, and an ultrahigh vacuum environment, which is costly and incompatible with serial semiconductor manufacturing techniques. Another promising avenue for renewable resists comes from biomacromolecules, which include silk, [ 12–14 ] wool keratin, [ 17 ] egg white, [ 15 ] spider silk, [ 16 ] and various polysaccharides. [ 18–21 ] Despite some inspiring success with these materials, protein‐based resists lack replication fidelity given their ambiguous composition and unpredictable molecular weight and distribution.…”

“…resources to replace the current petroleum-based resists, which are key materials in the semiconductor industry and are critical components of several emerging technologies from nanofluidic devices to quantum computing and artificial intelligent systems. [3] Toward this aim, ice, [4][5][6][7] dry ice, [8] small organic molecules, [9][10][11] and bio-based macromolecules [12][13][14][15][16][17][18][19][20][21] have been developed as burgeoning materials for micro-/nanomanufacturing via photo or electron beam lithography owing to their intrinsic renewability or recyclability. Although these sustainable resists have shown tremendous promise, questions remain concerning sensitivity, reproducibility, and compatibility with current lithographic protocols, as well as scaleup.…”

“…Furthermore, these nanofabrication processes require an ultralow operating temperature, including a specially designed heating/cooling stage, and an ultrahigh vacuum environment, which is costly and incompatible with serial semiconductor manufacturing techniques. Another promising avenue for renewable resists comes from biomacromolecules, which include silk, [12][13][14] wool keratin, [17] egg white, [15] spider silk, [16] The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.202007417. and various polysaccharides.…”

Sub-micron lines patterning into silica using water developable chitosan bioresist films for eco-friendly positive tone e-beam and UV lithography

“…With silk, although high resolution was also achieved (30 nm lines spaced by 100 nm for e-beam), selectivity to etching was not reported. Recently, a third group proposed egg white directly extracted from eggs as a resist 12 . But stripping of this resist was time consuming as the sample needed to be immersed in a solution of trypsin during 15 h which is not suited to a microelectronic process.…”