Lithography

About: Lithography is a research topic. Over the lifetime, 23507 publications have been published within this topic receiving 348321 citations.

Reduced Graphene Oxide Electrodes for Large Area Organic Electronics

Abstract: patterning of molecular electrode materials and carbon nanotubes. The interlayer technique involves the insertion of a layer of photoresist between the substrate and the fi lm to be patterned. The resist layer is exposed through a mask, generating a pattern that can subsequently be developed after deposition of the target material. Immersion in an appropriate developer removes the soluble parts of the resist layer together with the overlying target material, leaving a patterned fi lm of the target material over a likewise patterned fi lm of the resist. The resist and the target material are in effect patterned simultaneously in an expose‐ deposit‐develop step sequence. Furthermore, this technique is compatible with the use of standard solution processing and mechanical transfer methods for deposition of the target fi lms. Since interlayer lithography builds on the existing expertise and equipment of conventional photolithography, it is easy to implement and fully compatible with fast, cost effective sheet-to-sheet processing for large-area electronics.

Replica multichannel polymer chips with a network of sacrificial channels sealed by adhesive printing method

Abstract: Replica microchips for capillary array electrophoresis containing 10 separation channels (50 µm width, 50 µm depth and 100 µm pitch) and a network of sacrificial channels (100 µm width and 50 µm depth) were successfully fabricated on a poly(methyl methacrylate) (PMMA) substrate by injection molding. The strategy involved development of moving mask deep X-ray lithography to fabricate an array of channels with inclined channel sidewalls. A slight inclination of channel sidewalls, which can not be fabricated by conventional deep X-ray lithography, is highly required to ensure the release of replicated polymer chips from a mold. Moreover, the sealing of molded PMMA multichannel chips with a PMMA cover film was achieved by a novel bonding technique involving adhesive printing and a network of sacrificial channels. An adhesive printing process enables us to precisely control the thickness of an adhesive layer, and a network of sacrificial channels makes it possible to remove air bubbles and an excess adhesive, which are crucial to achieving perfect sealing of replica PMMA chips with well-defined channel and injection structures. A CCD camera equipped with an image intensifier was used to simultaneously monitor electrophoretic separations in ten micro-channels with laser-induced fluorescence detection. High-speed and high-throughput separations of a 100 bp DNA ladder and ϕX174 Hae III DNA restriction fragments have been demonstrated using a 10-channel PMMA chip. The current work establishes the feasibility of mass production of PMMA multichannel chips at a cost-effective basis.

Surface Nano- and Microstructuring with Organometallic Polymers

Abstract: This paper gives an overview of the use of poly(ferrocenylsilane)s in the surface patterningof silicon substrates. Due to the presence of iron and silicon in their main chain, poly(ferrocenylsilane)sshow a very high resistance to reactive ion etching, allowing one to transfer polymer patternsdirectly onto the substrate. Methods for introducing etch-resistant polymer patterns on substratesurfaces include soft lithography approaches such as microcontact printing, directed dewetting, andcapillary force lithography. Next to top-down methods, self-assembly strategies are discussed. Phaseseparation in thin films of asymmetric organic–organometallic block copolymers leads to theformation of nanoperiodic organometallic patterns. The use of such thin films as nanolithographictemplates is demonstrated. Surface patterning can also be realized using electrostatic self-assemblyof organometallic polyions. Layer-by-layer deposition of poly(ferrocenylsilane) polyanions and polycationson chemically patterned substrates allows one to guide the growth of multilayer thin films and toproduce patterned organometallic coatings.

Three-dimensional fabrication of heterogeneous microstructures using soft membrane deformation and optofluidic maskless lithography

Abstract: We propose a method for high-throughput generation of 3D microstructures using a membrane-mounted microfluidic channel. Utilizing an optofluidic maskless lithography system, photopolymerized 3D microstructures are fabricated in a layer-by-layer fashion with the thickness of each layer controlled by the deformation of the membrane. The combination of low numerical aperture optical systems for photopolymerization and a soft membrane for height control allows large area projection lithography with high vertical resolution, overcoming the trade-off between vertical resolution and the field-of-view. The material composition of each layer is varied using microfluidic control of photocurable resin and composite microstructures with heterogeneity in both lateral and vertical directions are generated. Using this technique, we demonstrate three-dimensional patterning of different types of cells in a hydrogel for a microfluidic platform to study co-culture and cell-to-cell interactions. The proposed technique is fast and simple, allowing parallel synthesis of complex heterogeneous 3D microstructures and in situ biomaterial patterning for microfluidic bioassays.