Mu-San Chen

Bio: Mu-San Chen is an academic researcher from United States Naval Research Laboratory. The author has contributed to research in topics: Reactive-ion etching & Metallizing. The author has an hindex of 17, co-authored 20 publications receiving 1076 citations. Previous affiliations of Mu-San Chen include Washington University in St. Louis.

Selective metallization process

Abstract: The invention is directed to a process for patterning a substrate in a selective pattern. In one embodiment, the process comprises the steps of forming a patterned coating over a substrate surface whereby portions of the substrate are covered by the patterned coating and portions of the substrate remain uncoated. A layer of a ligating material is coated over at least those portions of the substrate free of the patterned coating. The ligating layer is one that is capable of ligating with an electroless metal plating catalyst. The article so formed is then contacted with an electroless metallization catalyst and then with an electroless plating solution to form a patterned metal deposit on the substrate.

Fabrication and selective surface modification of 3-dimensionally textured biomedical polymers from etched silicon substrates

Abstract: A new method is described for producing biomedically relevant polymers with precisely defined micron scale surface texture in the x, y, and z planes. Patterned Si templates were fabricated using photolithography to create a relief pattern in photoresist with lateral dimensions as small as I μm. Electroless Ni was selectively deposited in the trenches of the patterned substrate. The Ni served as a resilient mask for transferring the patterns onto the Si substrate to depths of up to 8.5 μm by anisotropic reactive ion etching with a fluorine-based plasma. The 3-dimensional (3-D) textured silicon substrates were used as robust, reusable molds for pattern transfer onto poly(dimethyl siloxane), low density poly(ethylene), poly(L-lactide), and poly(glycolide) by either casting or injection molding. The fidelity of the pattern transfer from the silicon substrates to the polymers was 90 to 95% in all three planes for all polymers for more than 60 transfers from a single wafer, as determined by scanning electron microscopy and atomic force microscopy. Further, the 3-D textured polymers were selectively modified to coat proteins either in the trenches or on the mesas by capillary modification or selective coating techniques. These selectively patterned 3-D polymer substrates may be useful for a variety of biomaterial applications. © 1996 John Wiley & Sons, Inc.

Fabrication of biological nanostructures by scanning near-field photolithography of chloromethylphenylsiloxane monolayers.

Abstract: We demonstrate the fabrication of sub-100-nm DNA surface patterns by scanning near-field optical lithography using a near-field scanning optical microscope coupled to a UV laser and a chloromethylphenylsiloxane (CMPS) self-assembled monolayer (SAM). The process involves 244-nm exposure of the CMPS SAM to create nanoscale patterns of surface carboxylic acid functional groups, followed by their conversion to the N-hydroxysuccinimidyl ester and reaction of the active ester with DNA to spatially control DNA grafting with high selectivity.

Proximity X-ray lithography using self-assembled alkylsiloxane films: Resolution and pattern transfer

Abstract: Self-assembled films of octadecyltrichlorosilane (OTS) on Si/SiO2 were patterned with proximity X-rays (λ = 1.0 nm) in air, resulting in the incorporation of oxygen-containing functional groups, that is, hydroxyl and aldehyde, into the film. Unexposed and exposed OTS exhibited sufficient chemical contrast for patterning processes based on differences in wetting behavior and chemical reactivity. Latent images of features as small as ∼70 nm, defined by the X-ray mask, were successfully fabricated in the OTS with high fidelity over areas of ∼1 cm2. Patterned OTS was imaged directly with lateral force microscopy and indirectly through atomic force microscopy of three-dimensional structures formed on the surface of thin films of diblock copolymers after deposition and annealing on the patterned OTS. Pattern transfer of features with dimensions as small as ∼150 nm into the underlying silicon substrate was achieved by reactive ion etching using thin films of nickel selectively deposited onto the exposed areas of...

Ion beam modification and patterning of organosilane self‐assembled monolayers

Abstract: The patterning and modification of organosilane self‐assembled monolayers on Si native oxide surfaces by low‐ and high‐energy ion beams were investigated. The nature and extent of low‐energy (50–140 eV) Ar+ ion‐induced modification of a 2‐(trimethoxysilyl) ethyl‐2‐pyridine monolayer was studied by x‐ray photoelectron spectroscopy and by the quality of the electroless Nipatterns obtained. C(1s) and N(1s) core level x‐ray photoelectron spectroscopy indicated that the ion‐induced modification of the monolayer involved loss of the ethylpyridyl chain by sputtering and/or decomposition. The type of modification was independent of the ion energy and fluence, but the extent of modification depended on both parameters. The modification of the pyridine monolayer was monitored by the percent loss in the N(1s) peak area; modification commenced at a fluence of 5×1014 ions/cm2 and was observed for all ion energies studied. However, selective electroless metallization occurred only for monolayers that suffered ≳50% loss in the N(1s) x‐ray photoelectron spectroscopy signal. A damage saturation level of 80% N(1s) loss was indicated at an ion fluence of 9×1015 ions/cm2. A high‐energy focused ion beam lithography system was also used to evaluate the high resolution patterning of N‐(2‐aminoethyl)‐3‐aminopropyltrimethoxysilane, (aminoethylaminomethyl) phenethyltrimethoxysilane, and pyridine monolayers by Ga+, Si++, Au+, and Au++ ions at energies ranging from 50 to 280 keV. The highest resolution metal features obtained were 0.3‐μm‐wide gaps on phenethyltrimethoxysilane and pyridine monolayers using Ga+ and Si++ ions. Aminopropyltrimethoxysilane monolayers were found to require ten times higher ion fluences to achieve comparable results with the phenethyltrimethoxysilane and pyridine monolayers for all ions investigated.

Microfluidic large scale integration

Abstract: High-density microfluidic chips contain plumbing networks with thousands of micromechanical valves and hundreds of individually addressable chambers. These fluidic devices are analogous to electronic integrated circuits fabricated using large scale integration (LSI). A component of these networks is the fluidic multiplexor, which is a combinatorial array of binary valve patterns that exponentially increases the processing power of a network by allowing complex fluid manipulations with a minimal number of inputs. These integrated microfluidic networks can be used to construct a variety of highly complex microfluidic devices, for example the microfluidic analog of a comparator array, and a microfluidic memory storage device resembling electronic random access memories.

Plasma-surface modification of biomaterials

Abstract: Plasma-surface modification (PSM) is an effective and economical surface treatment technique for many materials and of growing interests in biomedical engineering This article reviews the various common plasma techniques and experimental methods as applied to biomedical materials research, such as plasma sputtering and etching, plasma implantation, plasma deposition, plasma polymerization, laser plasma deposition, plasma spraying, and so on The unique advantage of plasma modification is that the surface properties and biocompatibility can be enhanced selectively while the bulk attributes of the materials remain unchanged Existing materials can, thus, be used and needs for new classes of materials may be obviated thereby shortening the time to develop novel and better biomedical devices Recent work has spurred a number of very interesting applications in the biomedical field This review article concentrates upon the current status of these techniques, new applications, and achievements pertaining to biomedical materials research Examples described include hard tissue replacements, blood contacting prostheses, ophthalmic devices, and other products

Functionalizing nanoparticles with biological molecules: developing chemistries that facilitate nanotechnology.

Abstract: Chemistries that Facilitate Nanotechnology Kim E. Sapsford,† W. Russ Algar, Lorenzo Berti, Kelly Boeneman Gemmill,‡ Brendan J. Casey,† Eunkeu Oh, Michael H. Stewart, and Igor L. Medintz*,‡ †Division of Biology, Department of Chemistry and Materials Science, Office of Science and Engineering Laboratories, U.S. Food and Drug Administration, Silver Spring, Maryland 20993, United States ‡Center for Bio/Molecular Science and Engineering Code 6900 and Division of Optical Sciences Code 5611, U.S. Naval Research Laboratory, Washington, D.C. 20375, United States College of Science, George Mason University, 4400 University Drive, Fairfax, Virginia 22030, United States Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine, Sacramento, California 95817, United States Sotera Defense Solutions, Crofton, Maryland 21114, United States

Density multiplication and improved lithography by directed block copolymer assembly

Abstract: Methods to pattern substrates with dense periodic nanostructures that combine top-down lithographic tools and self-assembling block copolymer materials are provided. According to various embodiments, the methods involve chemically patterning a substrate, depositing a block copolymer film on the chemically patterned imaging layer, and allowing the block copolymer to self-assemble in the presence of the chemically patterned substrate, thereby producing a pattern in the block copolymer film that is improved over the substrate pattern in terms feature size, shape, and uniformity, as well as regular spacing between arrays of features and between the features within each array compared to the substrate pattern. In certain embodiments, the density and total number of pattern features in the block copolymer film is also increased. High density and quality nanoimprint templates and other nanopatterned structures are also provided.

Microfabricated elastomeric valve and pump systems

Abstract: A method of fabricating an elastomeric structure, comprising: forming a first elastomeric layer on top of a first micromachined mold, the first micromachined mold having a first raised protrusion which forms a first recess extending along a bottom surface of the first elastomeric layer; forming a second elastomeric layer on top of a second micromachined mold, the second micromachined mold having a second raised protrusion which forms a second recess extending along a bottom surface of the second elastomeric layer; bonding the bottom surface of the second elastomeric layer onto a top surface of the first elastomeric layer such that a control channel forms in the second recess between the first and second elastomeric layers; and positioning the first elastomeric layer on top of a planar substrate such that a flow channel forms in the first recess between the first elastomeric layer and the planar substrate.