bluuebunny/crossref_metadata_2025_split huggingface dataset:
Channel Cracking Technique for Toughness Measurement of Brittle Dielectric Thin Films on Silicon Substrates
Authors: Ma Qing , Xie Joseph , Chao Sam , El-Mansy Safaa , Mcfadden Robert , Fujimoto Harry 
Published: April 2011

AbstractA technique for the measurement of brittle thin film toughness has been developed. It is based on the mechanics of channel cracking in thin films. Dielectric films including CVD silicon oxide and silicon nitride films were studied using this technique. To prevent channel cracks from propagating into silicon substrates, an aluminum layer was deposited prior to the deposition of the dielectric layer. By using a specially made bending fixture, the cracks were observed in situ when the samples were subject to well controlled stresses. It was observed that for each film, a well defined critical film stress level existed, beyond which the crack velocity accelerated very rapidly. The critical film stresses were obtained by superposition of the critical applied stresses and the residual stresses in the films due to deposition and thermal expansion mismatch. It was shown that this technique was highly consistent in critical stress measurement. A simple shear-lag model was used to obtain the film toughness values using the measured critical film stress data.
The Reliability Assessment of Flip Chip Type Solder Joints Based on the Damage Integral Approach
Authors: Su Peng , Zhou Chen , Rzepka Sven , Korhonen Matt , Li Che-Yu 
Published: April 2011

AbstractThermal fatigue of flip-chip solder joints between a chip and chip carrier is a serious reliability concern. Differences in the temperature and/or in the coefficients of thermal expansion between the chip and substrate lead to stresses which may result in fatigue damage and eventual failure of the interconnect. Conventionally, the solder lives have been estimated by a Coffin-Manson type relation. However, this largely empirical approach becomes inadequate when comparing thermal histories that are widely different, as in the cases of accelerated thermal cycling and power cycling. In this study, we use a damage integral approach where the fatigue damage rate is calculated based on the momentary stress and strain (estimated analytically) experienced by the solder joints. The momentary damage is then integrated over the entire loading history to yield total damage at any moment.
Tensile Testing of Ultra-Thin-Film Materials Deposited on Polyimide for Mems Applications
Authors: Tregilgas J.H. , Strumpell M. 
Published: April 2011

AbstractA newly developed approach to thin-film tensile testing has been utilized for evaluating ultra-thin-films of about 60-100 nm in thickness. Thin sputtered metal films deposited on 3.5 gm thick polyimide film substrates were tested using a Mesotronix nanotensiometer. Modifications to sample handling and zero strain calibration helped to improve testing reproducibility. The response of a thin-film metal was determined by subtracting the response of the polyimide carrier film from that of the metal-on-polyimide composite. Stress-strain curves for two amorphous alloys sputtered from Al-25 at% Ti and Nb-25 at% Al targets exhibited well-defined elastic regions followed by brittle behavior. The ultimate tensile strengths (UTS) were about 1200 MPa for the Al-Ti and 1700 MPa for the Nb-Al, both of which occurred near the elastic strain limit of about 2%. After recrystallization at 280°C for an hour, the Al-Ti film showed what appears to be an upper and lower yield point, in addition to strain hardening. Initial yielding occurred at a strain of about 1.2% and a stress of about 800 MPa, while the UTS of about 1000-1060 MPa occurs at strains as high as 9%. Stress relaxation measurements performed on both the amorphous and the recrystallized films showed lower values of stress relaxation at 1% strain compared to low alloy polycrystalline Al films.
Measurement of Elastic Modulus and Poisson's Ratio of Diamond–Like Carbon Films
Authors: Cho Sung-Jin , Lee Kwang-Ryeol , Eun Kwang Yong , Ko Dae-Hong 
Published: April 2011

AbstractElastic modulus and Poisson's ratio of diamond-like carbon (DLC) film was measured by a simple method using DLC bridges which are free from mechanical constraint of substrate. The DLC films were deposited on Si wafer by C6H6r.f. glow discharge at the deposition pressure 1.33 Pa. Because of the high residual compressive stress of the film, the bridge exhibited a sinusoidal displacement by removing the constraint of the substrate. By measuring the amplitude with known bridge length, we could determine the strain of the film required to adhere to the substrate. Combined with independent stress measurement by laser reflection method, this method allows calculation of the biaxial elastic modulus, E/(1–v), where E is the elastic modulus and v Poisson's ratio of the DLC film. By comparing the biaxial elastic modulus with plane-strain modulus, E/(1–v2), measured by nano-indentation, we could further determine the elastic modulus and Poisson's ratio, independently. The elastic modulus, E, increased from 87 to 133 GPa as the negative bias voltage increased from 400 to 550 V. Poisson's ratio was estimated to be about 0.20 in this bias voltage range. For the negative bias voltages less than 400 V, however, the present method resulted in negative Poisson's ratio which is physically impossible. The limitation of the present method was also discussed.
Residual Stress of Silicon Films Deposited by Lpcvd From Silane
Authors: Temple-Boyer P. , Imbernon E. , Rousset B. , Scheid E. 
Published: April 2011

AbstractIn this paper, amorphous, semi-crystalline and polycrystalline silicon films have been deposited by low pressure chemical vapour deposition (LPCVD) from silane SiH4 by ranging the deposition temperature from 555 to 635°C and the total pressure from 100 to 300 millitorrs. Films residual stresses have been determined thanks to the formula of Stoney by measurements of the wafer curvature before and after removal of the back side deposition. The influences of the different deposition parameters are reported and major stress variations are evidenced. By studying the effects of a 600°C crystallisation anneal and by comparing them to those observed for amorphous silicon films deposited from disilane Si2H6, compressive and tensile stresses are respectively related to “surface” and “volume” crystallisation phenomena. The different stress values of amorphous and polycrystalline silicon have been estimated and, according to these results, solutions are finally proposed in order to have a real control of residual stress into silicon depositions and to obtain low stress (σ ≈ 0) polysilicon films.
Silicon-Based Epitaxial Films for Mems
Authors: Fitzgerald E.A. , Wu K.C. , Currie M. , Gerrish N. , Bruce D. , Borenstein J. 
Published: April 2011

AbstractThe objective of this work was to develop an improved wet etch-stop technology for silicon micromachining. To establish a reference for process improvement, the diffusion process currently used to fabricate p++ Si:B etch stops was comprehensively investigated. Subsequently, a novel germanium- based epitaxial etch-stop technology was developed.A range of techniques were used to study p++ silicon layers created by boron diffusion into (001) silicon wafers. The results revealed gradients in boron and lattice constant, as well as a graded three- dimensional dislocation array from lattice-mismatch stress. The gradients in boron concentration and dislocation density can lead to curl in micromachined structures. Although annealing steps can remove the boron gradient, a flat membrane will be a tenuous balance.Epitaxial films of p++Si:B and strain-compensated p++Si1-xGex:B can remove composition gradients and improve process control. However, it is undesirable to depend on p-type layers doped at levels near the solubility limit to prevent etching. We have therefore developed a unique etch stop created from relaxed SiGe alloys. Etch-stop behavior quite similar to heavily boron-doped silicon has been demonstrated in undoped silicon-germanium. Neither strain nor defects are responsible for the etch-stop behavior. A model is proposed based on energy band structure and a SiOx passivation mechanism.
Curvature of A Cantilever Beam Subjected to An Equi-Biaxial Bending Moment
Authors: Krulevitch P. , Johnson G.C. 
Published: April 2011

AbstractResults from a finite element analysis of a cantilever beam subjected to an equi-biaxial bending moment demonstrate that the biaxial modulus E/(1-v) must be used even for narrow beams.
Formation of Continuous Cubic Mesoporous Films by Spin Casting
Authors: Honma I. , Zhou H.S. , Kundu D. 
Published: April 2011

AbstractThe simple spin casting technique has been successfully used for producing mesoporous thin films on glass substrate. The films are found to be homogeneous and continuous in a large size scale, however, the mesostructural phase of the film has been controlled systematically among amorphous (A), one-dimensional hexagonal (1-dH), cubic (C) and Lamellae (L) by increasing surfactant to TEOS concentration ratio in the casting solution. The 1-dH as well as cubic structure is thermally stable after the calcination so that a mesoporous thin film is obtained by surfactant removal. The solution additives of 1-propanol and 2-butanol might play a roll in the direct formation of the primitive cubic phase in the film form which has never been obtained.
Polyhedral Oligomeric Silsesquioxanes (Poss): Silicon Based Monomers and their Use in the Preparation of Hybrid Polyurethanes
Authors: Schwab Joseph J. , Lichtenhan Joseph D , Chaffee Kevin P. , Mather Patrick T , Romo-Uribe Angel 
Published: April 2011

AbstractA series of Polyhedral Oligomeric Silsesquioxane (POSS) monomers bearing reactive hydroxyl functionalities, suitable for incorporation into step-growth polymers, is described. These monomers are difunctional in nature and are particularly well suited for use as chain extenders in the synthesis of polyurethanes. This work describes the synthesis of these POSS monomers and their incorporation into a series of polyurethanes. Preliminary thermal, mechanical and rheological data for the POSS containing polyurethanes will also be discussed.
Hybrid Organic-Inorganic Electrode-Membranes Based on Organo-Polysiloxane/Macrocycle Systems
Authors: Jiménez-Morales A. , Galvan J.C. , Aránda P. , Ruiz-Hitzky E. 
Published: April 2011

AbstractSpecific complexing agents for alkaline ions such as some crown-ethers of different intramolecular cavity size (12-crown-4, 15-crown-5 and 18-crown-6) are incorporated into a organo-polyorganosiloxane network generated via the sol-gel process. The resulting xerogels embody macrocycle compounds with different ion-selectivity. These xerogels are deposited onto porous supports (borosilicate, polyacrylonitrile,…) to obtain new composite electrode- membranes. The electrochemical characterization of the membranes and the electrode- membranes by electrochemical impedance spectroscopy (EIS) shows information about the reversible behavior and the ion resistance of the membranes, which are a function of both, nature and content of the entrapped macrocycle as well as the salt solution concentration. The electrochemical response of these systems acting as electrode-membranes shows their sensitivity towards different metal ions at variable concentrations.
New Inorganic-Organic Hybrid Polymers for Integrated Optics
Authors: Roscher Christof , Buestrich Ralf , Dannberg Peter , Rösch Oliver , Popall Michael 
Published: April 2011

AbstractNew fluorinated inorganic-organic hybrid polymers (ORMOCER*s) for integrated optics were synthesized via hydrolysis and condensation (sol-gel processing) of functionalized pentafluorophenylalkoxysi lanes followed by organic crosslinking reactions. Process parameters (catalyst, temperature and ratio of educts) were optimized to achieve low transmission losses at the most important wavelengths for telecommunication in the NIR range: 1310 nm and 1550 nm.The result is a photopatternable transparent ORMOCER (negative resist behavior) with excellent low losses: 0.20 dB/cm at 1310 nm and 0.30 dB/cm at 1550 nm.Besides their high transparency the fluorinated ORMOCERs show a variety of other properties enabling their use as waveguide materials within the production of optoelectronic devices and related thin film technology: good wetting and adhesion on various substrates (e.g. glass, silicon and several polymers), low processing temperatures (postbake below 160 °C), high thermal stability (decomposition > 250°C) and a tunable refractive index.
Aqueous Sol-Gel Derived Nanocomposite Coating Materials
Authors: Schmidt H.K. , Arpac E. , Schirra H. , Sepeur S. , Jonschker G. , Claflin B. , Lucovsky G. , Claflin B. , Lucovsky G. , Claflin B. , Lucovsky G. 
Published: April 2011

AbstractSol-gel reactions, in general, have to take place in organic solvents in order to control the hydrolysis and condensation reaction. This leads to drawbacks in applications, since the organic solvent vapor concentration has to be controlled for example in coating applications for environmental, health or security reasons. For this reason, a reaction route has been developed to produce coating precursors stable against water as solvent. To achieve this, conventional electrostatically stabilized sols obtained either by hydrolysis and condensation or commercially available sols (e.g. SiO2sols) have been surface-modified to reduce the particle-to-particle interaction and electrosterically stabilized precursors compatible to water have been obtained. By use of alkoxy silanes as surface modifiers, water-dispersable nanoparticulate liquid coating systems have been prepared, for example, with boehmite, SiO2 or TiO2 as nanoparticles to be crosslinked after coating thermally by inorganic condensation and organic condensation or polymerization reactions. Thus, aqueous sol-gel coating systems have been prepared with EtOH contents below 5 %. In the paper, the basic reaction as well as material properties will be discussed.
Sheet and Tube Organosilicon Polymers
Authors: Katsoulist D. E. , Chaot T. C.-S. , McQuistont E. A. , Chen Chenggang , Kenney Malcolm E. , Claflin B. , Lucovsky G. , Claflin B. , Lucovsky G. 
Published: April 2011

AbstractReaction of chlorosilanes with sheet silicates, such as the naturally occurring apophyllite, [Ca4Si8O2O(F, OH).8H2O] results in the formation of sheet organofunctional siloxane polymers. Similarly, reaction of chlorosilanes with the tube silicate K2CuSi4O10results in the formation of tube organofunctional siloxane polymers. Representative polymers have been characterized by XRD, KR, XPS and solid state 29Si NMR. The interlayer spacing of the sheet polymers varies with the type of the group pendent on the sheet. When the organofunctional pendent groups of the sheet polymers contain reactive sites, further reactivity can be demonstrated with heterogeneous reactions such as hydrosilation. The sheet polymers behave as very effective thickeners of siloxane fluids. Dispersions of them in siloxane fluids exhibit thixotropic properties. The organosilicon polymers have the potential to show useful chemical, thermal, rheological and mechanical properties
Synthesis and Structural Characterization of Organically-Modified Microporous Silicates
Authors: Babonneau F. , Leite L. , Fonlupt S. , Ribot F. , Bergogne L. , Roux C. 
Published: April 2011

AbstractOrganically-modified silicates have been synthesized from RSi(OEt)3 (R = CH3, C2H5, C8H17, CH2=CH, C6H5) and TEOS under acidic conditions, in the presence of cethyltrimethylammonium (CTAB). The introduction of RSiO1.5 units with R/Si =0.2, affects the ordering of the expected hexagonal silicate phase, except when R = C6H5. The sample containing phenyl functions was thus submitted to surfactant extraction; calcination at 350°C appears to be more efficient, and less disruptive for the network ordering than a washing procedure in ethanol. Nitrogen adsorption measurements on the hexagonally ordered calcined sample that still contains phenyl groups, yields a type I isotherm, typical of a microporous solid. BET method leads to a surface area of 1000 m2/g and a pore volume of 0.32 cm3/g.
Catalytic Materials by Design from Hybrid Organic-Inorganics
Authors: Joël  , Moreau J.E. , Man Michel Wong Chi 
Published: April 2011

AbstractThe sol-gel processing of appropriated molecular precursors easily leads to a variety of hybrid organic-inorganic materials with intrinsic properties. This approach is increasingly becoming an interesting way to prepare heterogeneous catalysts. The paper will focus on the use of hybrids for the preparation of selective catalytic materials. Two examples of the use of hybrid polysilsesquioxanes polymers will be given. i) The tailoring of the pore structure of silicas, under mild reaction conditions, based on the temporary introduction of different organic substructures in the hybrid network of polysilsesquioxane gels will be discussed. ii) Also the preparation of new chiral hybrid supports for enantioselective catalysis will be presented.
Characterization and Reactivity of Hybrid Organosilicate Mesoporous Sieves
Authors: Lim M. , Stein A. 
Published: April 2011

AbstractVinyl-MCM-41 has been synthesized by a direct synthesis from the corresponding organosiloxane precursors. The location of vinyl groups on the internal channel surfaces of the mesoporous silicate sieves was confirmed by small angle neutron scattering (SANS) experiments using contrast matching techniques. To investigate further modification of the vinyl groups, bromination reactions were carried out on vinyl-MCM-41 samples in dichloromethane, carbon tetrachloride, and in a gas-phase reaction. With dichloromethane as a solvent, the bromination rate increased with increasing pore diameter. A strong dependence of the reaction rate on the presence and type of solvent molecules was observed. While gas-phase bromination was complete within 40 minutes, the reaction required several days for completion in dichloromethane and was even slower in the nonpolar solvent, carbon tetrachloride.
New Techniques for the Nanostructural Characterization of Semiconductor Materials and Devices Using Combined Focused Ion Beam and Transmission Electron Microscopy Techniques
Authors: Hull R. , Dunn D. 
Published: April 2011

AbstractWe describe novel techniques which extend the range of available nanostructural characterization capability for semiconductor materials and devices. These techniques combine high spatial resolution imaging and spectroscopy using transmission electron microscopy (TEM) and focused ion beam (FIB) microscopy. Specific capabilities described include nanoscale imaging of dopant distributions, ultra-high resolution secondary ion mass spectroscopy (SIMS) and tomographic image reconstruction.
The Challenge and Methods of TEM Cross-Sectioning of < 0.25 Micron Plugs
Authors: Hunt C. Amy , Zhang Yuhong , Su David 
Published: April 2011

AbstractTransmission electron microscopy (TEM) is a useful tool in process evaluation and failure analysis for semiconductor industries. A common focus of semiconductor TEM analyses is metalization vias (plugs) and it is often desirable to cross-section through a particular one. If the cross-sectional plane deviates away from the center of the plug, then the thin adhesion layer around the plug will be blurred by surrounding materials such as the inter-layer dielectric and the plug material. The importance of these constraints, along with the difficulty of precision sample preparation, has risen sharply as feature sizes have fallen to 0.25 μm and below. The suitability of common sample preparation techniques for these samples is evaluated.
Probing Stress State and Phase Content in Ultra-Thin Ta Films
Authors: Whitacre J. F. , Rek Z. U. , Yalisove S. M. , Bilello J. C. 
Published: April 2011

ABSTRACTTa films 25Å to 200Å in thickness were sputter-deposited using different sputter gas (Ar) pressures and cathode power settings. The average in-plane stresses were determined using double crystal diffraction topography (DCDT). X-ray analysis (using the grazing incidence x-ray scattering (GIXS) geometry) was performed using a synchrotron light source. To study microstructure and phase content, transmission electron microscopy (TEM) and transmission electron diffraction (TED) were used. Well resolved x-ray patterns were collected for all of the films. The DCDT stress data was found to be consistent with stress effects evident in the GIXS data. In general, residual stress state was not strongly dependent upon Ar pressure. The strongest evidence of amorphous content was found in both x-ray and TED data taken from 25Å thick films deposited using 2mTorr Ar pressure and 460 W cathode power. These results show that it is possible to create and study ultra-thin Ta films which posses a range of residual stresses and phase compositions.
Application of Synchrotron X-Ray Fluorescence Microscopy to the Study of Multi-Metal Oxide Ceramics
Authors: Perry Dale L. , McHugo Scott , Thompson Albert C. , Farmer Joseph C. , Ebbinghaus Bart B. , Konynenburg Richard Van , Brummond William A. , Armentrout Guy , Gould Thomas H. , Yang Nancy 
Published: April 2011

ABSTRACTSynchrotron x-ray fluorescence microscopy has been used to study multi-metal oxide ceramics that have been designed to sequester radioactive actinide elements for long-term storage and disposal. X-ray fluorescent lines for the various elements have been used for lateral elemental mapping of the materials, and the heterogeneity of the samples is discussed with respect to the elements in the crystallographic phases that have previously been documented by other means of structural and chemical analyses.
Expansive Reactions in Concrete Observed by Soft X-Ray Transmission Microscopy
Authors: Kurtis K. E. , Monteiro P. J. M. , Brown J. T. , Meyer-Ilse W. 
Published: April 2011

ABSTRACTAlkali-silica reaction, sulfate attack, and reinforcing steel corrosion can compromise the long-term durability of concrete structures. The anticipated economic impact of an extensive infrastructure repair scheme has produced a renewed interest in the development of advanced characterization methods to assess the degree of deterioration in the concrete experiencing these deleterious reactions. The products of the alkali silica reaction, sulfate attack, and corrosion as well as the cement hydration products are extremely sensitive to humidity. Consequently, characterization techniques that require high vacuum or drying, as many existing techniques do, are not particularly appropriate for the study of these reactions in concrete as artifacts are introduced. A high resolution instrument which allows the examination of these reactions and their products without drying and at normal pressures will promote understanding of the reactions and provide further insight into means of mitigating the damage they cause. Only soft x-ray transmission microscopy provides the required high spatial resolution to observe the reaction process in situ. The alkali-silica reaction can be observed over time, in a wet condition, and at normal pressures, features unavailable with most other high resolution techniques. Soft x-rays also reveal information on the internal structure of the sample. This paper reviews published and ongoing applications of soft x-ray transmission microscopy for the study of expansive reactions that occur in concrete.