Shadow Edge Lithography and Application to Nanofluidics

Author(s):  
Woon-Hong Yeo ◽  
Dong Won Lee ◽  
Kyong-Hoon Lee ◽  
Jae-Hyun Chung

Many upcoming applications, such as nanoelectronic circuitry, single-molecule based chips, nanofluidics, chemical sensors, and fuel cells, require large arrays of nanochannels and nanowires. To commercialize such nanostructured devices, a high resolution and high throughput patterning method is essential. For this purpose, we developed the shadow edge lithography (SEL) as a wafer-scale, high-throughput nanomanufacturing method [1]. In the proposed method, the shadow effect in the high-vacuum evaporation was theoretically analyzed to predict the geometric distribution of the nanoscale patterns [2]. In experiment, nanoscale patterns were created by the shadow of aluminum (Al) edges that were prepatterned using a conventional microfabrication method.

Author(s):  
John Guofeng Bai ◽  
Jae-Hyun Chung

We propose shadow edge lithography (SEL) as a wafer-scale nanofabrication method. The shadow effect of “line-ofsight” in high-vacuum evaporation is analyzed theoretically to predict the geometric distributions of the fabricated nanoscale gaps. In the experiment, nanoscale gap patterns are created by the shadow of Al edges which are prepatterned using e-beam evaporation and the conventional ultraviolet lithography. Feasibility of the SEL is demonstrated by the fabrication of nanogaps having the width ranging from 15 to 100 nm on 4-inch Si wafers. Furthermore, by using the height differences in the prepatterned Al edges to compensate the geometric distributions of the shadow effect, it is demonstrated that the uniformity tolerance in the nanogap width can be ±1 nm or ±5% across the 4-inch Si wafers at a resolution down to 20 nm. The experimental results agree well with the theoretical prediction considering the virtual source during the e-beam evaporation. Upon the nanogap fabrication, arrays of nanochannels are obtained by reactive ion etching (RIE) using the evaporated Al layers as the etching mask. Our results show that that the evaporated Al layers can be used as the RIE mask to transfer the nanoscale patterns with a high yield and throughput. Thus, the SEL provides a robust method for wafer-scale fabrication especially for sub 50-nm structures.


Author(s):  
A. V. Crewe

The high resolution STEM is now a fact of life. I think that we have, in the last few years, demonstrated that this instrument is capable of the same resolving power as a CEM but is sufficiently different in its imaging characteristics to offer some real advantages.It seems possible to prove in a quite general way that only a field emission source can give adequate intensity for the highest resolution^ and at the moment this means operating at ultra high vacuum levels. Our experience, however, is that neither the source nor the vacuum are difficult to manage and indeed are simpler than many other systems and substantially trouble-free.


Author(s):  
J. P. Langmore ◽  
N. R. Cozzarelli ◽  
A. V. Crewe

A system has been developed to allow highly specific derivatization of the thymine bases of DNA with mercurial compounds wich should be visible in the high resolution scanning electron microscope. Three problems must be completely solved before this staining system will be useful for base sequencing by electron microscopy: 1) the staining must be shown to be highly specific for one base, 2) the stained DNA must remain intact in a high vacuum on a thin support film suitable for microscopy, 3) the arrangement of heavy atoms on the DNA must be determined by the elastic scattering of electrons in the microscope without loss or large movement of heavy atoms.


Author(s):  
George C. Ruben

Single molecule resolution in electron beam sensitive, uncoated, noncrystalline materials has been impossible except in thin Pt-C replicas ≤ 150Å) which are resistant to the electron beam destruction. Previously the granularity of metal film replicas limited their resolution to ≥ 20Å. This paper demonstrates that Pt-C film granularity and resolution are a function of the method of replication and other controllable factors. Low angle 20° rotary , 45° unidirectional and vertical 9.7±1 Å Pt-C films deposited on mica under the same conditions were compared in Fig. 1. Vertical replication had a 5A granularity (Fig. 1c), the highest resolution (table), and coated the whole surface. 45° replication had a 9Å granulartiy (Fig. 1b), a slightly poorer resolution (table) and did not coat the whole surface. 20° rotary replication was unsuitable for high resolution imaging with 20-25Å granularity (Fig. 1a) and resolution 2-3 times poorer (table). Resolution is defined here as the greatest distance for which the metal coat on two opposing faces just grow together, that is, two times the apparent film thickness on a single vertical surface.


Author(s):  
Frank Altmann ◽  
Jens Beyersdorfer ◽  
Jan Schischka ◽  
Michael Krause ◽  
German Franz ◽  
...  

Abstract In this paper the new Vion™ Plasma-FIB system, developed by FEI, is evaluated for cross sectioning of Cu filled Through Silicon Via (TSV) interconnects. The aim of the study presented in this paper is to evaluate and optimise different Plasma-FIB (P-FIB) milling strategies in terms of performance and cross section surface quality. The sufficient preservation of microstructures within cross sections is crucial for subsequent Electron Backscatter Diffraction (EBSD) grain structure analyses and a high resolution interface characterisation by TEM.


Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 83
Author(s):  
Ritika Singh Petersen ◽  
Anja Boisen ◽  
Stephan Sylvest Keller

Microparticles are ubiquitous in applications ranging from electronics and drug delivery to cosmetics and food. Conventionally, non-spherical microparticles in various materials with specific shapes, sizes, and physicochemical properties have been fabricated using cleanroom-free lithography techniques such as soft lithography and its high-resolution version particle replication in non-wetting template (PRINT). These methods process the particle material in its liquid/semi-liquid state by deformable molds, limiting the materials from which the particles and the molds can be fabricated. In this study, the microparticle material is exploited as a sheet placed on a deformable substrate, punched by a robust mold. Drawing inspiration from the macro-manufacturing technique of punching metallic sheets, Micromechanical Punching (MMP) is a high-throughput technique for fabrication of non-spherical microparticles. MMP allows production of microparticles from prepatterned, porous, and fibrous films, constituting thermoplastics and thermosetting polymers. As an illustration of application of MMP in drug delivery, flat, microdisk-shaped Furosemide embedded poly(lactic-co-glycolic acid) microparticles are fabricated and Furosemide release is observed. Thus, it is shown in the paper that Micromechanical punching has potential to make micro/nanofabrication more accessible to the research and industrial communities active in applications that require engineered particles.


Author(s):  
Xiaojia Jiang ◽  
Mingsong Zang ◽  
Fei Li ◽  
Chunxi Hou ◽  
Quan Luo ◽  
...  

Biological nanopore-based techniques have attracted more and more attention recently in the field of single-molecule detection, because they allow the real-time, sensitive, high-throughput analysis. Herein, we report an engineered biological...


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