bluuebunny/crossref_metadata_2025_split huggingface dataset:
Laser Processing of Parmod™ Functional Electronic Materials
Authors: Kydd Paul H. , Richard David L. , Chrisey Douglas B. , Church Kenneth H. 
Published: April 2011

ABSTRACTParmod™ is a family of materials that can be printed and thermally cured to create metallic conductors on printed wiring boards. This additive process provides a way to produce circuitry direct from CAD files without the necessity for intermediate tooling of any kind. The printed images are converted to pure metallic traces in seconds at a temperature low enough to be compatible with commonly used rigid and flexible polymer-based substrates. This simple, two-step process eliminates the hazardous wastes and employee health and safety issues associated with conventional plate-and-etch photolithographic technologyRecently the Parmod™ technology has been extended from metals to oxides to enable printing passive electronic components such as resistors, capacitors and inductors, as well as the metallic interconnects. While thermal curing of the oxides provides useable electronic properties, particularly of resistors and capacitors, the performance of all these novel materials could be improved by laser processing. This paper discusses preliminary results on laser processing of Parmod™ conductors and components in two different systems
Ion Beam Induced Chemical Vapor Deposition of Dielectric Materials
Authors: Wanzenboeck H.D. , Lugstein A. , Langfischer H. , Bertagnolli E. , Gritsch M. , Hutter H. 
Published: April 2011

ABSTRACTDirect writing by locally induced chemical vapor deposition has been applied to direct-write tailor-made microstructures of siliconoxide for modification and repair of microelectronic circuits. Focused ion beam (FIB) tools are used for locally confined deposition of dielectric material in the deep sub-µm range. State-of-the-art procedures typically provide insufficient dielectrics with high leakage currents and low breakdown voltage. The detailed investigation of the deposition mechanisms in this study proposes an approach to significantly improve dielectric material properties. Siloxane and oxygen as volatile precursors introduced in a vacuum chamber are used to deposit siliconoxide at ambient temperatures on various substrates such as Si, GaAs, or metals. The deposition process was initiated by a focused Ga+-beam. As elementary electronic test vehicles for a systematic electrical investigation ion beam induced depositions in of capacitor architectures are applied. The chemical composition of the layers is investigated by secondary ion mass spectroscopy (SIMS) and reveals effects of atomic mixing at the interfaces. The variation of process parameters such as ion energy and ion dose, scan time and delay time lead to a better understanding of the mechanisms. The composition of the precursor gas mixture is of significant influence on insulating properties. The results demonstrate that optimized FIB-induced deposition of dielectrics offers a new window for in-situ post-processing of integrated circuits
Electrical Characteristics of Thermal Spray Silicon Coatings
Authors: Tan S.Y. , Gambino R.J. , Goswami R. , Sampath S. , Herman H. 
Published: April 2011

ABSTRACTPolycrystalline silicon deposits were formed on a monocrystalline silicon substrate by thermal spraying. The resulting structure exhibits a device characteristic. Pressure-induced transformations of silicon, namely, Si-III (BC-8) and Si-IX are identified by X-ray diffraction in a Si-I matrix on deposits formed by vacuum plasma spray. The presence of the Si-III and Si-IX indicates that the pressure-quenched silicon deposit is highly conductive, as determined by four-point van der Pauw resistivity measurement. Hall mobility measurements, combined with photoconductivity results, indicate that the highly conductive silicon deposit displays the same range of mobility as a polycrystalline deposit containing only Si-I. The silicon deposit, with or without metastable phases, displays the same photoconductivity properties. The silicon deposit on a monocrystalline silicon substrate exhibits rectifying I–Vcharacteristics, possibly caused by band bending of trapping states associated with impurities segregating at the polycrystalline deposit/monocrystalline substrate interface
Synthesis and Radical Polymerization of Pyrocarbonate Functionalized Monomers: Application to Positive-Tone Photoresists
Authors: Vansteenkiste S.O. , Marleé Y. , Schacht E.H. , Damme M. Van , van Aert H. , Vermeersch J. 
Published: April 2011

ABSTRACTThe synthesis of two new tert-butyl carbonic anhydride monomers, 4-vinylbenzoic and methacrylic tert-butyl carbonic anhydride was achieved successfully. Radical polymerization at 45°C yielded tert-butyl pyrocarbonate protected materials. Thermographic analysis showed that both polymers decompose cleanly at 135°C. The lithographic performance of both materials was evaluated in presence of 2,4,6-tris-(trichloromethyl)-s-triazine as photoacid generating species. It was demonstrated that the large polarity change resulted in a chemically amplified positive photoresist system
Manufacture of Microelectronic Circuitry by Drop-on-Demand Dispensing of Nano-particle Liquid Suspensions
Authors: Szczech J.B. , Megaridis C.M. , Gamota D.R. , Zhang J. 
Published: April 2011

ABSTRACTAn emerging selective metallization process utilizes Drop-On-Demand (DOD) inkjet printing, and recent developments in nano-particle fluid suspensions to fabricate fine-line circuit interconnects. The suspensions consist of silver or gold particulates of 1–10 nm in size that are homogeneously suspended in an organic carrier solvent. A piezo-electric droplet generator driven by a bipolar voltage signal is used to dispense 50–70 µm diameter droplets traveling at 1-3 m/s before impacting a compliant substrate. The deposit/substrate composite is subsequently processed at 300°Cfor 15 minutes to allow for evaporation of the solvent carrier and sintering of the nano-particles, thereby yielding a finished circuit product. Test vehicles created using this technique exhibited features as fine as 120–200 µm wide and 1–3 µm thick. The circuitry performed well during environmental conditioning studies. However, repeatability of the results showed sensitivity to the generation of steady, satellite-free droplets. In an effort to generate droplets consistently, it is essential to develop a strong fundamental understanding of the correlation between device excitation parameters and fluid properties, and resolve the microrheological behavior of the conductive ink as it flows through the droplet generator.
Using Convective Flow Splitting for the Direct Printing of Fine Copper Lines
Authors: Cuk T. , Troian S.M. , Hong C.M. , Wagner S. 
Published: April 2011

ABSTRACTWe have developed a technique for the printing of copper lines using solutions of a metal organic precursor, copper hexanoate. A 500-µm written liquid line is observed to split into two 100-µm wide lines. We observe further splitting into four parallel lines in experiments with written lines of copper hexanoate solution in chloroform. Surface profiles indicate that the thickness, width and number of lines formed are strongly dependent on the solution viscosity and volume per unit length deposited. From particle tracking visualization and surface profiling, we have found that evaporative cooling produces Marangoni convection patterns that accrete the solute along two key boundaries of flow
Ink Jet Deposition of Ceramic Suspensions: Modeling and Experiments of Droplet Formation
Authors: Reis N. , Derby B. 
Published: April 2011

ABSTRACTWe have successfully printed green ceramic objects from slurries of Al2O3 dispersed in paraffin wax using a commercial ink-jet printer developed for pattern making (Sanders Prototype MM6PRO). Concentrated suspensions are generally more viscous than the fluids normally passed through ink jet heads. This may alter the response of the printing system to its process parameters, e.g. driving voltage and frequency. We have explored the influence of fluid properties on the ink jet behaviour using Computational Fluid Dynamics (CFD) modelling and a parallel experimental study to determine the optimum printing conditions for particulate suspensions.
A UV Direct-Write Approach for Formation of Embedded Structures in Photostructurable Glass-Ceramics
Authors: Fuqua P.D. , Taylor D.P. , Helvajian H. , Hansen W.W. , Abraham M.H. 
Published: April 2011

ABSTRACTPhotostructurable glass-ceramics are a promising class of materials for MEMS devices. Previous work micromachining these materials used conventional photolithography equipment and masking techniques; however, we use direct-write CAM tools and a pulsed UV laser micromachining station for rapid prototyping and enhanced depth control. We have already used this class of materials to build components for MEMS thrusters, including fuel tanks and nozzles: structures that would prove difficult to build by standard microfabrication techniques.A series of experiments was performed to characterize process parameters and establish the processing trade-offs in the laser exposure step. The hypothesis that there exists a critical dose of UV light for the growth of an etchable crystalline phase was tested by exposing the material to a fluence gradient for a variety of pulse train lengths, and then processing as usual. By measuring the dimensions of the etched region, we were able to determine the dose. We found that the dose is proportional to the square of the per-pulse fluence. This has allowed us to create not only embedded structures, but also stacked embedded structures. This also implies that we can embed tubes and tunnels with a single exposure inside a monolithic glass sample. We feel that this technique has promise for a number of applications, including microfluidics.
Direct Patterning of Hydrogenated Amorphous Silicon by Near Field Scanning Optical Microscopy
Authors: Hollingsworth Russell E. , Bradford William C. , Herndon Mary K. , Beach Joseph D. , Collins Reuben T. 
Published: April 2011

ABSTRACTPractical methods for directly patterning hydrogenated amorphous silicon (a-Si:H) films have been developed. Direct patterning involves selectively oxidizing the hydrogen passivated aSi:H surface, with the oxide then serving as an etch mask for subsequent hydrogen plasma removal of the unoxidized regions. Photo induced oxidation has been extensively studied using both far field projected patterns and near field scanning optical microscopy (NSOM) for direct write patterning. Examination of the threshold dose for pattern generation for excitation wavelengths from 248 to 633nm provides indirect evidence for involvement of electron-hole recombination in optically induced oxidation. Optical exposure of a-Si:H in vacuum demonstrated that oxygen must be present in the ambient atmosphere during exposure for successful pattern generation. This suggests that oxidation of the surface may not involve removal of hydrogen, but rather breaking of Si-Si backbonds and insertion of oxygen. An additional mechanism for oxide generation was observed whereby pattern generation resulted from simple proximity of an NSOM probe within ∼30nm from the sample surface. The probe dither amplitude was found to greatly affect the line width and height of patterns generated without light. Line widths of approximately 100nm, comparable to the probe diameter, were obtained.
Pattern Writing by Implantation in a Large-Scale PSII System With Planar Inductively Coupled Plasma Source
Authors: Wu Lingling , Gao Hongjun , Manos Dennis M. 
Published: April 2011

AbstractA large-scale plasma source immersion ion implantation (PSII) system with planar coil RFI plasma source has been used to study an inkless, deposition-free, mask-based surface conversion patterning as an alternative to direct writing techniques on large-area substrates by implantation. The apparatus has a 0.61 m ID and 0.51 m tall chamber, with a base pressure in the 10−8 Torr range, making it one of the largest PSII presently available. The system uses a 0.43 m ID planar rf antenna to produce dense plasma capable of large-area, uniform materials treatment. Metallic and semiconductor samples have been implanted through masks to produce small geometric patterns of interest for device manufacturing. Si gratings were also implanted to study application to smaller features. Samples are characterized by AES, TEM and variable-angle spectroscopic ellipsometry. Composition depth profiles obtained by AES and VASE are compared. Measured lateral and depth profiles are compared to the mask features to assess lateral diffusion, pattern transfer fidelity, and wall-effects. The paper also presents the results of MAGIC calculations of the flux and angle of ion trajectories through the boundary layer predicting the magnitude of flux as a function of 3-D location on objects in the expanding sheath.
Electrostatic Printing, a Versatile Manufacturing Process for the Electronics Industries
Authors: Detig Robert H. 
Published: April 2011

AbstractFunctional materials configured as liquid toners are printed on a variety of substrates for various manufacturing processes. The materials include metal toners, resistor toners, high k dielectric toners, phosphors and glass. The substrates printed upon include glass, bare and coated metal, polymeric films and even paper. A fixed configuration electrostatic printing plate is used in most manufacturing applications though traditional photo receptor plates can be used if electronic addressability is desired.Applications of electrostatic printing for electronic packaging products (printed wiring boards and flex circuits) and of passive electronic components themselves will be shown. Results with a pure silver toner printed on both glass and paper will be reported. Examples of passive electronic components like resistors, capacitors, and even inductors that have been electrostatically printed with liquid toners will be shown. Possible applications of toners to the manufacture of flat panel displays will be discussed.
Processing of Organic/Inorganic Composites by Stereolithography
Authors: Lee J. H. , Prud'homme R. K. , Aksay I. A. 
Published: April 2011

AbstractCeramic StereoLithography (CSL) is used to fabricate complex shaped ceramic powder compacts by laser photocuring a concentrated ceramic dispersion in photocuring solutions layer-by-layer. The main processing parameters in CSL such as layer thickness, resolution, hatch spacing, and overcure depend on knowledge of the light propagation in a concentrated dispersion. In studies dealing with the processing of ceramic-filled organics, we investigated the depth of curing for model resin systems as a function of photoinitiator concentration. An optimal photoinitiator concentration that maximized the gel cure depth was observed The study showed that photoinitiator plays a significant role in controlling the quality and performance of the formed gel network, with special regard to thickness of cured layers. This has potential application to fields as diverse as industrially cured coatings and dental fillings, and more generally, 3-dimensional fabrication techniques.
Freeform Fabrication of Ceramics by Hot-Melt Ink-Jet Printing
Authors: Derby B. , Reis N. , Seerden K.A.M. , Grant P.S. , Evans J.R.G. 
Published: April 2011

AbstractInk-jet printing is a versatile freeform fabrication technique with a high spatial resolution. By suspending ceramic particles in low melting point organic materials and printing above the melting point, rapid cooling on impact after printing results in rapid layer growth. Current results from a collaborative programme studying the hot wax ink-jet printing of structural ceramic components will be reported. The influence of key fluid properties on the ink-jet deposition process are discussed.
Conformal Cooling Versus Conventional Cooling: An Injection Molding Case Study With P-20 and 3DP™-Processed Tooling
Authors: Schmidt Wayde R. , White Ronald D. , Bird Connie E. , Bak Joseph V. 
Published: April 2011

AbstractA series of designed experiments was performed in an attempt to evaluate and quantify the historically “anecdotal” benefits of conformal cooling for injection molding tooling. The study considered different generic part geometries, gating schemes, mold materials, plastic resins and cooling approaches. This paper provides an overview of the mold design approach, cooling simulation, tool fabrication via the 3DP™ process, as well as part molding and inspection results.
Microstructural Evolution in cryomilled Inconel 625
Authors: He Jianhong , Lavernia Enrique J. 
Published: April 2011

ABSTRACTNanocrystalline Inconel 625 alloy, with a uniform distribution of grains, was synthesized using cryogenic mechanical milling. Microstructures of the powder, cryomilled for different times, were investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results indicated that both the average powder particle size and average grain size approached constant values as cryomilling time increased to 8 hours. The TEM observations indicated that grains in the cryomilled powder were deformed into elongated grains with a high density of deformation faults, and then fracturedviacyclic impact loading in random directions. The fractured fragments from the elongated coarse grains formed nanoscale grains. The occurrence of the elongated grains, from development to disappearance during intermediate stages of milling, suggested that repeated strain fatigue and fracture caused by the cyclic impact loading in random directions, and cold welding were responsible for the formation of a nanocrystalline structure.
Mechanical Properties of Nanocrystalline Ni in Relation to its Microstructure
Authors: Torre F. Dalla , Swygenhoven H. Van , Victoria M. , Schaeublin R. , Wagner W. 
Published: April 2011

ABSTRACTMechanical properties of nanocrystalline Ni made by Inert Gas Condensation and Electrodeposition are presented in relation to their microstructure. Significant plasticity is only observed at elevated temperatures for both types of nanocrystalline Ni. However, a higher temperature is needed in the Inert gas condensated material. Careful analysis of the microstructure by means of X-ray diffraction and conventional electron microscopy reveal initial differences in as-prepared samples. The change in microstructure during deformation at elevated temperatures and during heat treatment without external load is investigated and information about the deformation mechanisms is reported.
The Effect of Deposition Parameters on Tensile Properties of Pulse-Plated Nanocrystalline Nickel
Authors: Morgan K. L. , Ahmed Z. , Ebrahimi F. 
Published: April 2011

ABSTRACTThe microstructure and tensile properties were investigated for pulse-plated nanocrystalline nickel electrodeposits prepared from an additive-free sulfamate-based solution. Square-wave cathodic current densities were varied from 25 to 75 mA/cm2. The samples deposited at 25 mA/cm2showed the smallest grain size (d ∼ 12 nm), and the grain size was found to increase with increasing current densities. The grain size of the electrodeposits ranged from approximately 27 to 12 nm. Tensile results indicated that the yield strength of the specimens increased with decreasing grain size. Scanning electron microscopy revealed that all electrodeposits fractured through a ductile mechanism.
Extension of High Cycle Fatigue Life by the Formation of Nano-Sized Martensite Particles at Intersections of Dislocations in an Austenitic Stainless Steel
Authors: Inamura T. , Shimojo M. , Takashima K. , Higo Y. 
Published: April 2011

ABSTRACTA new fatigue strengthening method which is applicable for both the micro-sized materials and ordinary-sized materials have been proposed. Dislocations are pinned at their intersections by the formation of nano-crystals after cold work in this strengthening method.Nano-sized α'-martensite particles, the diameter of which was approximately 5 nm, were formed by a cryogenic treatment at a certain temperature above(martensite burst starting temperature) in a commercially available 316-type austenitic stainless steel. These nano-particles are considered to be formed at intersections of dislocations. Fatigue life tests using ordinary-sized specimens revealed that high cycle fatigue life of the 316-type austenitic stainless steel was extended by the cryogenic treatment and this is considered to be due to the pinning of dislocations by the formation of nano-sized α'-martensite particles.
Novel Tungsten Carbide Nanocrystalline Composites by Pulsed Laser Deposition
Authors: Venkatesan Ravi K. , Kvit A. , Wei Q. , Narayan J. 
Published: April 2011

ABSTRACTWe have developed a novel processing technique to fabricate “artifact free” tungsten carbide (WC) nanocomposites. In this method, pulsed laser deposition of WC in conjunction with a few monolayers of nickel aluminide (NiAl) is used to control the grain size of nanocrystalline composites. The grain size of WC was controlled by the thickness of tungsten carbide and the substrate temperature. The role of NiAl is to ensure the nucleation of tungsten carbide islands, and it is also insoluble in WC. Using this approach, we have fabricated nanocomposites of grain sizes ranging from 6 nm to 35 nm. The hardness of the composite increases with the decrease in grain size, following approximately Hall-Petch relationship. The role of NiAl in grain boundary deformation is of particular interest in strengthening the nanocrystalline composites. The potential of this technique to go to even lower grain sizes is discussed.
Processing and Properties of Ceramic Nanocomposites Produced from Polymer Precursor Pyrolysis, High Pressure Sintering and Spark Plasma Sintering
Authors: Wan Julin , Gasch Matt J. , Kuntz Joshua D. , Mishra Rajiv , Mukherjee Amiya K. 
Published: April 2011

ABSTRACTSilicon nitride/silicon carbide nanocomposites and alumina-based nanocomposites were investigated in an effort to produce materials with high structural integrity and service properties. Bulk nano-nano composites of silicon nitride and silicon carbide were processed by crystallization of amorphous Si-C-N ceramics that were consolidated in-situ during pyrolysis of a polymer precursor. This material was developed for the purpose of examining the creep behavior of covalent ceramics when there is no oxide glassy phase at grain boundaries. Si3N4/SiC micro-nano composites were sintered by spark plasma sintering (SPS), aiming at better microstructural control and improved creep resistance. Composites of alumina with diamond, silicon carbide and metal (Nb) were developed by high pressure sintering and SPS. These composites maintain microstructures with a nanometric alumina matrix and are targeted for studying the toughening mechanisms and superplastic deformation mechanisms.