MEMS Lithography and Micromachining Techniques

Hines, D. R.; Siwak, Nathan; Mosher, L. A.; Ghodssi, Reza

doi:10.1007/978-0-387-47318-5_9

Cited by 7 publications

(5 citation statements)

References 175 publications

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“…We thus predicted that a flip of the size difference would result in the formation of hollow nanorings in DLPL and that the theoretical ring width would On the basis of the results of SLPL experiments, an optimal exposure time for DLPL was determined. In DLPL, since energy loss takes place when UV light penetrates the overlying negative photoresist, 53 the exposure energy received by the positive photoresist underneath is smaller compared to that of SLPL. As a result, the features generated by a positive photoresist in DLPL are equivalent to those generated with lower intensities or shorter exposure times in SLPL.…”

Section: Resultsmentioning

confidence: 83%

“…g ., UV light intensity, soft-baking time, development time) were held fixed. Theoretically, the feature sizes should increase with the added exposure time or exposure energy . As a result, features generated by both photoresists shared similar size-increasing patterns (see Figure a,b).…”

Section: Resultsmentioning

confidence: 99%

“…Theoretically, the feature sizes should increase with the added exposure time or exposure energy. 53 As a result, features generated by both photoresists shared similar size-increasing patterns (see Figure 2a,b). Overall, as the exposure time increased from 18 to 38 s, the feature size of the positive photoresist increased by 1.8 μm (3.9−5.7 μm), whereas the feature size of the negative photoresist increased by 0.7 μm (4.2−4.9 μm) (detailed measurements are provided in Table S1 of the Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

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Single-Step Dual-Layer Photolithography for Tunable and Scalable Nanopatterning

Liu

Wang

et al. 2021

ACS Nano

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Conventional photolithography, due to its scalability, robustness, and straightforward processes, has been widely applied to micro-and nanostructure manufacturing in electronics, optics, and biology. However, optical diffraction limits the ultimate resolution of conventional photolithography, which hinders its potential in nanoscale patterning for broader applications. Here, we introduce a derivative of conventional photolithography for nanoscale patterning called dual-layer photolithography (DLPL), which is based on the controlled exposure and development of overlapping positive and negative photoresists. In a typical experiment, substrates are sequentially coated by two layers of photoresists (both positive and negative). Then, we purposefully control the exposure time to generate slightly larger features in the positive photoresist than those in the negative photoresist. After development, their overlapping areas become the final features, which outline the original features. We demonstrate line widths down to 300 nm here, which can be readily improved with more precise control. By adjusting the lithography parameters and material deposition, the feature sizes, shapes (e.g., rings, numbers, letters), line widths (300−900 nm), and materials (e.g., SiO 2 , Cr, and Ag) of these features can be independently controlled. Combined with anisotropic etching, more complex three-dimensional nanostructures can be fabricated as well, as we demonstrate here with Si. We further fabricate photodetectors as an example application to show that these nanostructures fabricated by DLPL can be used to promote light-trapping MAPbI 3 perovskite films to achieve good photoelectric properties. This strategy is not limited to ultraviolet photolithography and may also be incorporated into other energetic beam-based lithographic approaches, including deep and extreme ultraviolet photolithographies and electron beam lithography, to enhance their resolution.

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Section: Resultsmentioning

confidence: 83%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Single-Step Dual-Layer Photolithography for Tunable and Scalable Nanopatterning

Liu

Wang

et al. 2021

ACS Nano

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“…Photolithography was initially developed in the micro-electromechanical field [52]. It applies light, such as ultraviolet light or laser, combined with a photomask to develop micro and nanopatterns on photoresist films (figure 3(c)).…”

Section: Lithography-based Methodsmentioning

confidence: 99%

Biomimetic and bioinspired surface topographies as a green strategy for combating biofouling: a review

Vellwock¹,

Yao²

2021

Bioinspir. Biomim.

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Biofouling refers to the adverse attachment and colonization of fouling organisms, including macromolecules, bacteria, and sessile invertebrates, on the surfaces of materials submerged in aquatic environments. Almost all structures working in watery surroundings, from marine infrastructures to healthcare facilities, are affected by this sticky problem, resulting in massive direct and indirect economic loss and enormous cost every year in protective maintenance and remedial cleaning. Traditional approaches to preventing marine biofouling primarily rely on the application of biocide-contained paints, which certainly impose adverse effects on the ocean environment and marine ecology. Biomimicry offers an efficient shortcut to developing environmentally friendly antifouling techniques and has yielded encouraging and promising results. The antifouling strategies learned from nature can be broadly classified into two categories according to the nature of the cues applied for biofouling control. One is the chemical antifouling techniques, which are dedicated to extracting the effective antifoulant compounds from marine organisms and synthesizing chemicals mimicking natural antifoulants. In contrast, the physical biomimetic (BM) antifouling practices focus on the emulation and optimization of the physical cues such as micro and nanoscale surface topographies learned from naturally occurring surfaces for better antifouling efficacy. In this review, a synopsis of the techniques for manufacturing the BM and bioinspired (BI) antifouling surface topographies is introduced, followed by the bioassay to assess the antifouling performance of the structured surfaces. Then, the BM and BI surface topographies that were reported to possess enhanced antifouling competence are introduced, followed by a summary of theoretical modeling. The whole paper is concluded by summarizing the studies' deficiencies so far and outlooking the research directions in the future.

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“…Lithography and micromachining techniques ( Figure 3C ) have been used to create 2.5D scaffolds, patterns and pillars. To create the structures, a pattern is transferred from a mask to a photosensitive polymer layer ( Hines et al, 2011 ). According to the nature of the photopolymer (negative or positive tone), it is possible to obtain either polymeric 2.5D scaffolds ( Accardo et al, 2018b ) or silicon ones ( Limongi et al, 2013 ).…”

Section: Fabrication Techniques and Materials For Scaffold-based 3d C...mentioning

confidence: 99%

Engineered cell culture microenvironments for mechanobiology studies of brain neural cells

Ransanz

Altena²,

Heine³

et al. 2022

Front. Bioeng. Biotechnol.

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The biomechanical properties of the brain microenvironment, which is composed of different neural cell types, the extracellular matrix, and blood vessels, are critical for normal brain development and neural functioning. Stiffness, viscoelasticity and spatial organization of brain tissue modulate proliferation, migration, differentiation, and cell function. However, the mechanical aspects of the neural microenvironment are largely ignored in current cell culture systems. Considering the high promises of human induced pluripotent stem cell- (iPSC-) based models for disease modelling and new treatment development, and in light of the physiological relevance of neuromechanobiological features, applications of in vitro engineered neuronal microenvironments should be explored thoroughly to develop more representative in vitro brain models. In this context, recently developed biomaterials in combination with micro- and nanofabrication techniques 1) allow investigating how mechanical properties affect neural cell development and functioning; 2) enable optimal cell microenvironment engineering strategies to advance neural cell models; and 3) provide a quantitative tool to assess changes in the neuromechanobiological properties of the brain microenvironment induced by pathology. In this review, we discuss the biological and engineering aspects involved in studying neuromechanobiology within scaffold-free and scaffold-based 2D and 3D iPSC-based brain models and approaches employing primary lineages (neural/glial), cell lines and other stem cells. Finally, we discuss future experimental directions of engineered microenvironments in neuroscience.

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MEMS Lithography and Micromachining Techniques

Cited by 7 publications

References 175 publications

Single-Step Dual-Layer Photolithography for Tunable and Scalable Nanopatterning

Single-Step Dual-Layer Photolithography for Tunable and Scalable Nanopatterning

Biomimetic and bioinspired surface topographies as a green strategy for combating biofouling: a review

Engineered cell culture microenvironments for mechanobiology studies of brain neural cells

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