bluuebunny/crossref_metadata_2025_split huggingface dataset:
The AC-Indentation Technique and its Application to Al and Al-Si Coatings
Authors: Wu T.W. 
Published: March 2011

AbstractAn ac-microindentation technique, namely indenting with a small displacement modulation superimposed on an otherwise linear indenter motion, will be introduced. The basic principle and theory will also be illustrated by using a mechanical model to simulate the indenter behavior.Other than being as capable as conventional indentation, the ac-technique acquires the unloading slope simultaneously and continuously with the penetration depth and applied load during an entire indentation process. With this extra information, the conversion between the total depth and plastic depth can be executed right after a single indentation, and in turn the hardness as well as. contact modulus depth profiles can be calculated. This is in contrast to the conventional indentation technique where a group of indentations associated with different maximum loads are required in order to achieve the same purpose. Furthermore, it also avoids the subjectivity in the selection of the fitting portions from the unloading stage of an indentation curve to extract the unloading slopes as well as the plastic penetration depths.Another important advantage of using this ac-technique is the high sensitivity in detecting the indenter/surface contact. This advantage is very useful in the determination of the origins of penetration depths as well as in the investigation the evolution of the contact area, and both issues are very crucial in the microhardness calculations.The strain rate effect on the hardness measurements of a 1 μm thick Al-2%Si coating has been demonstrated by using the ac-technique. As the indenter loading speed increases from 2.5 to 10 nm/sec, the measured hardness of the coating can be increased from ∼20% to ∼80% depending on the penetration depth, and the shallower the penetration depth the larger the increment is. However, the contact modulus depth profiles remain unchanged for all the indentation rates.
Laser Ultrasonic Measurement of Thin Film Elastic Properties
Authors: Bobbin Sarah E. , Wagner J. W. , Cammarata R. C. 
Published: March 2011

AbstractA technique is presented for measurement of elastic properties of thin films from 0.001-0.025 mm in thickness. Lamb Waves were excited in free standing films with a pulsed Nd:YAG laser, and detected using heterodyne interferometry. Elastic properties were calculated from time-of-flight measurements. Variability in waveform structure with film thickness was observed, and interpreted with respect to extraction of elastic property information. An explanation is offered for changes in waveform structure, and common features are highlighted.
Fracture Strength of A1203 Insulating Thin Film for High Density Wiring Substrate
Authors: Jono Masahiro , Sugeta Atsushi 
Published: March 2011

AbstractFracture strength of amorphous A1203 insulating thin film coated on a Fe-42%Ni base metal was Investigated under static and cyclic loadings by using four point bending apparatus. It was found that the both static and cyclic fracture strength of thin film decreased with increasing coating thickness and also fracture under cyclic loading occurred at a strain below the static fracture strength. Observations In detail by the optical and scanning electron microscopes revealed that the splash particles deposited in coating process caused crack initiation origins. Evaluation method of fracture strength of thin films was discussed based on the fracture mechanics approach.
A Micromechanical Analysis of the Signal Propagation in Composite Materials
Authors: Chen C. S. 
Published: March 2011

AbstractMicrostructure of composite materials can have a profound effect upon the performance of microelectronics composed of those composite materials. Conventional analysis based on quasi-homogeneous models neglecting the structural details of the composites is inadequate. Micromechanical analysis is more complex but can provide a more realistic treatment. We have investigated the propagation of a signal in a periodic composite to examine the essential of a micromechanical analysis. By analyzing the state of the composite material just before and after the wave front as well as on both sides right next to the interfaces, we have determined the strength of the propagating signal. The results show that the property differential between material components is critical in determining the energy dissipation. In composite materials made of dissipative components such as polymers,structural details of the composite materials contribute further to the energy dissipation.
A New Approach to Evaluate the Delayed Fracture Behavior of an Optical Glass Fiber
Authors: Muraoka M. , AbÉ H. 
Published: March 2011

AbstractThe method for the direct measurement of subcritical crack growth in silica optical fiber with 125μm in diameter was developed. The obtained crack velocity da/dt as a function of stress intensity factor KI was expressed by means of log da/dt vs log KI linear relation with slope n. The obtained value of n showed 22.6 (25 °C,60%r.h.) with small standard deviation 0.7. These results indicate that the postulated crack growth law used for the lifetime prediction is valid and the present approach can solve the problem in the conventional method for evaluating the value of n where the evaluated value has been widely scattered.
Stress Induced Void Nucleation in Narrow Aluminum Alloy Lines
Authors: Børgesen P. , Korhonen M. A. , Basa C. , Lafontaine W. R. , Land B. , Li C.-Y. 
Published: March 2011

AbstractThe stress induced failure of passivated aluminum based metallizations is the combined result of the stress induced void nucleation and growth of voids. The present work investigates the dependence of the void nucleation on aging temperature and cooling rate. Narrow Al, Al(0.2%Cu) and Al(2%Si) lines of different widths were fabricated by lift-off and passivated with various thicknesses of Si3N4. After a 400°C anneal, the specimens were cooled directly to the selected aging temperature and aged for up to 1100 hours. Void nucleation was found to occur predominantly during the initial cool-down. The rate of nucleation varied in quite different ways with the combination of aging temperature and cooling rate for the different alloys, which is consistent with a grain boundary sliding controlled nucleation mechanism.
The Effect of Line Geometry on Void Growth in Thin, Narrow Aluminum Lines
Authors: Borgesen P. , Lee J. K. , Korhonen M. A. , Li C.-Y. 
Published: March 2011

AbstractThe stress induced growth of individual voids in passivated Al-lines at room temperature was monitored in-situ without removing the passivation. The kinetics was strongly influenced by variations in line gec.etry, even over distances of many Am, indicating variations in the stress relaxation as well.
A Comparison of the Metallurgical Behavior of Gold and Copper Wires in Ball Bonding
Authors: Uno Tomohiro , Tatsumi K. , Mizuno K. , Kitamura O. , Ohno Y. 
Published: March 2011

AbstractA comparison was made of gold and copper wires used in ball bonding in terms of their mechanical properties, bondability and the reliability of their bond interfaces in elevated temperature environments. The ball bondability of copper and gold was evaluated through clarification of the factors which govern ball deformability. Moreover a bonding method to suppress the generation of silicon cracks was proposed for ball bonding of copper wire. As to the reliability of the heat affected zone and the bond interfaces, copper wire was found to be superior to gold wire.
The Effect of Process on Performance and Reliability in a One Step Silver-Glass Die Attach Adhesive
Authors: Conlon A.M. , Cameron C.P. , Lau J.W. 
Published: March 2011

AbstractSilver-glass die attach adhesives provide a cost effective means of producing high reliability parts which can withstand the environmental testing required of electronic components. One step processing of these adhesives provides the additional advantages of increased throughput and processing flexibility compared to eutectically bonded assemblies.This paper describes the performance of a one step silver-glass die attach adhesive processed under various time and temperature conditions. The effect of peak firing temperature and dwell time on the ultimate tensile strength of the adhesive will be discussed. Tensile data from parts subjected to thermal shock, thermal cycle and high temperature aging will be presented as an indication of the material's long term reliability.
Numerical Analysis of the Bali. Forming Process in Copper Ball Bonding
Authors: Iiongyuan Fang , Yiyu Oian , Yihong Jiang 
Published: March 2011

AbstractIn this paper, the forming process of copper wire ball in copper ball bonding has been studied by numerical analysis. By means of calculation of temperature field, speed field and displacement field for ultrafine copper wire under a miniarc, the regular pattern of copper wire ball formation has been clarified. In this paper, the calculating result of displacement field has also been tested and verified.
Mechanical Behavior of Encapsulants in Microelectronic Packaging
Authors: Wong C.P. 
Published: March 2011

AbstractA modern electronic device is a complex 3-dimensional structure that consists of millions of components for each single IC chip. This complex and delicate device requires effective encapsulation and packaging to ensure its long-term reliability. The device encapsulant requires not only excellent electrical, physical properties, but also suitable mechanical properties for the hostile and extreme temperature cycling requirements. Hence, the mechanical behavior of the encapsulant plays a critical role in the device reliability.Low stress encapsulants are the preferred choice for microelectronic packaging. Silicone-base materials, with their low modulus and excellent electrical properties, are one of the best encapsulants. However, the intrinsic elastic (to soft gel-like) silicone properties provide weak mechanic protection of the IC device. We have, however, modified the silicone material with a high loading of silica to improve its mechanical and physical properties. This high silica filler loading material improves its mechanical property, but it also increases its modulus. This modified high modulus silicone material tends to have microcracks during the high temperature cycling testing. In this paper, I will describe a modified version of the enhanced mechanical property silicone-base encapsulant, the materials formulation, the curing and the thermal mechanical protecting mechanism and its application to AT&T's No. 5 Electronic Switching System (ESS) Gated Diode Crosspoint (GDX) hybrid IC supplemental insulating layer (SIL) materials.
Elastomeric Conductors for Electrical Contacts
Authors: Zhu Mingguang , Chung D.D.L. 
Published: March 2011

AbstractTwo new elastomeric electrical conductors were developed. One is silicone infiltrated tin foam containing 14 vol.% tin. The other is short nickel fiber silicone-matrix composites containing 3-12 vol.% fibers, fabricated by the impregnation of silicone into a nickel fiber preform. Both exhibited volume electrical resistivity of the order 10-4 ohm.cm.
Rigid-Rod And Segmented Rigid-Rod Polyimides: GEL/SOL And Liquid Crystalline Transitions, Fibers And Films
Authors: Cheng Stephen Z. D. , Arnold Fred E. , Eashoo Mark , Lee Song-Koo , Hsu Steve L. C. , Lee Chul Joo , Harris Frank W. 
Published: March 2011

ABSTRACTOrgano-soluble rigid-rod and segmented rigid-rod polyimides and their copolyimides exhibit isotropic solutions in hot m-cresol, but form gels upon cooling. A lyotropic liquid crystal phase is observed below the gel/sol transition. Mechanical gel formation is caused by liquid-liquid phase separation, while the liquid crystal phase may be formed through a nucleation process after gelation. High performance fibers can be spun from the hot isotropic solutions using a dry-jet wet spinning method. After the fibers are drawn at high temperatures, they display tensile strength higher than 3.2 GPa and an initial modulus higher than 130 GPa. In particular, the fibers retain relatively high mechanical properties at elevated temperatures. Solution casted films exhibit very low thermal expansion coefficients and dielectric constants. Their structure, morphology and property relationships will also be discussed.
Physical Characterization Of Microelectronic Polymeric Thin Films
Authors: Senturia Stephen D. , Noe Susan C. , Pan Jeffrey Y. 
Published: March 2011

ABSTRACTThe measurement of the mechanical properties and adhesion of polymeric thin films and coatings poses a number of technical problems. Elastic and viscoelastic properties, residual stress, adhesion, the effects of extended cure, and the effects of adsorbed moisture and process reagents are all critical. A particular challenge is to develop measurement methods which can be used with actual samples, preferably non-destructively. This paper examines a number of methods which have been developed to make these measurements, with emphasis on methods which are sensitive enough to look at the effects of process variation and the effects of moisture exposure. Suspended-membrane methods for measuring elastic and viscoelastic properties, residual stress, and adhesion are combined with optical methods for determining index of refraction and birefringence to yield a family of techniques for performing physical characterization. Recent results on the effects of extended cure and moisture uptake on elastic properties, residual stress, and optical properties will be presented.
Internal Stress Development In Spin Coated Polyimide Films
Authors: Pottiger Michael T. , Coburn John 
Published: March 2011

ABSTRACTThe effect of processing on the development of internal stresses in spin coated polyimide films was investigated. The internal stresses are a result of the coefficient of thermal expansion (CTE) mismatch between the polymer and the substrate. Birefringence and CTE were used to characterize the in-plane molecular orientation. In-plane orientation was shown to be sensitive to processing conditions. Increasing the spin speed results in higher in-plane orientation as observed by an increase in birefringence and a corresponding decrease in CTE. Heating rate during cure was observed to have a significant effect on in-plane orientation. Faster heating rates during cure resulted in a lower birefringence. The lower birefringence is attributed to relaxation effects that can occur during a rapid cure. The decrease in orientation was accompanied by an increase in internal stress.
Polyimide Planarization With Polystyrene By Rie Etch-Back
Authors: Ng Hung Y. , Lii T. , Jaso M. 
Published: March 2011

ABSTRACTThis paper reports the results of a planarization process of polyimide which has been utilized as a passivation material in multilevel interconnection. The degree of planarization with spin-coated polyimide over metal topography is only 10–20% due to crosslinking and shrinking of the polymer during the curing process. Polystyrene used as sacrificial planarizing film can achieve <95% planarity over 100μm metal pad with 1μm height. A conformal polystyrene film can be spin-coated onto the polyimide surface without adhesion promoter. The topography of polyimide over the metal pattern can be planarized with thermal reflow of the polystyrene by baking the film below 250°C. The planarity of this sacrificial film, polystyrene, can be transferred to polyimide by etch-back without degrading the polyimide surface properties which has been examined by X-ray photoelectron spectroscopy.
Preparation Of Moisture Resistant Polylmide Films By Plasma Treatment
Authors: Petrich Mark A. , Lu Hsueh Yi 
Published: March 2011

ABSTRACTPolyimides are an important class of polymeric materials used in microelectronics fabrication. These polymers could be used even more extensively if it were possible to improve their moisture resistance. We are using plasma processing techniques to modify the moisture resistance of polyimide films. Films are exposed to nitrogen trifluoride plasmas to introduce fluorine into the surface of the polyimide. Fluorination is monitored with x-ray photoelectron spectroscopy and Fourier transform infrared absorption spectroscopy. Water contact angle measurements are used to assess the hydrophobicity of the treated surfaces. Thus far, we have demonstrated that this plasma treatment is a good way of introducing fluorine into the polyimide surface, and that these treatments do enhance the hydrophobic nature of polyimide.
The Role Of Surface Modification On Adhesion At The Metal/Polymer Interface
Authors: Berry M. J. , Turlik I. , Smith P. L. , Adema G. M. 
Published: March 2011

ABSTRACTThis paper presents studies of surface modifications of benzocyclobutene (BCB) using reactive ion etching (RIE), ion implantation, and combinations of those in conjunction with liftoff processing steps. It was found that O2/N2 RIE treatments of the BCB surface improve the adhesion of subsequently evaporated chromium and copper. Implant treatments with C+, O+, Si+, As+, and Sb+, were also investigated. The implant treated samples exhibited improved adhesion prior to subsequent heat treatments in the Cr/BCB structures and some improvement subsequent to heat treating in the Cu/BCB structures. Combinations of the surface modification treatments were seen to have the greatest benefit, even after heat treatments.
A Study Of The Interface Between Polyimide And Plated Copper
Authors: Morihiro Yoshiyuki , Miyake Kurumi , Mori Mitsumasa , Kurokawa Hiroshi , Kohara Masanobu , Nunoshita Masahiro 
Published: March 2011

ABSTRACTA polyimide (PI) surface is analyzed by XPS at each electroless-copper-plating step. Zn ions are adsorbed on the PI surface, and subsequently replaced with Pd ions. Cu is deposited on the PI surface catalyzed by these Pd ions, As the surface concentration of Pd ions increases, the adhesive strength of the plated Cu to the PI surface increases.In the case of PI fabrication onto a plated Cu, no significant PI degradation is observed.
Chain Conformations Of Aromatic Polvimides And Their Ordering In Thin Films.
Authors: Yoon D. Y. , Parrish W. , Depero L. E. , Ree M. 
Published: March 2011

ABSTRACTWe have investigated the conformation – order relationships of four aromatic polyimides prepared by thermal imidization of the precursor poly(amic acids) in thin films. They are: (i) PMDA-4,4′-ODA polyimide from pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (ODA) monomers; (ii) PMDA-PDA polyimide from PMDA andp-phenylene diamine (PDA); (iii) PMDA-Benzidine polyimide from PMDA and benzidine and (iv) BPDA-PDA polyirnide from biphenylene tetracarboxylicdianhydride (BPDA) and PDA. X-ray diffraction results and their analyses by molecular modeling show that all the four polyimides exhibit extended chain conformations in various smectic-type ordered structures that form monomer repeat layers but differ in the details of interchain packing. Furthermore, the polyimide chains are highly aligned along the film plane.
Property Control Of New Fluorinated Copolyimides And Their Applications
Authors: Sasaki S. , Matsuura T. , Nishi S. , Ando S. 
Published: March 2011

ABSTRACTNew fluorinated copolyimides are synthesized with 2,2′-bis(trifluoromethyl)-4,4′- diaminobiphenyl (TFDB) and a mixture of 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and pyromellitic dianhydride (PMDA). The thermal expansion coefficient decreases with decreasing 6FDA content, because the hexafluoroisopropylidene group makes the main chain flexible. The refractive index decreases with increasing 6FDA content, because the fluorine content increases. The thermal expansion coefficient can be controlled between -0.5 × 10−5 and 8×10−5 /°C, and the refractive index can be controlled between 1.556 and 1.647 at 589.3 nm, by changing the 6FDA content. The polyimides and copolyimides from TFDB can be used in optical filters because of their high optical transparency and low thermal expansion coefficient. They are expected to be used in optical waveguides because of their high optical transparency and refractive index control.
Highly Temperature Resistant Silicone Ladder Polymers
Authors: Adachi Hiroshi , Adachi Etsushi , Yamamoto Shigeyoshi , Kanegae Hirozho 
Published: March 2011

ABSTRACTHigh purity high molecular weight poly (phenylsilsesquioxane) (PPSQ) has been synthesized and specimen films prepared by a solvent casting method. The decomposition temperature of the material is 550°C in air. A PPSQ specimen cured at 350°C for 60 min has a weight loss of 1% when held at 460°C for 60 min. A specimen initially dried at 200°C for 30 min then held at 460°C loses twice as much. The main constituent of the volatile material from PPSQ pyrolyzed at 500 °C for 60 min is benzene, which is 5.7% of the specimen weight. The tensile strength for the cured specimen is 8.0 × 109 dyne/cm2 at 25 °C, and 5.5 × 109 dyne/cm2 at 250°C. The strength of the dried specimen is 4.0 × 109 dyne/cm2 at 250°C and about one half that at 25°C. The thermal expansion coefficient for the cured specimen is 11−14 × 10−5 /°C over a temperature range from 5°C to 350°C. Residual stress is 2.8 × 108 dyne/cm2 at 25°C and one order lower at 350°C.
Electrooptic Materials Requirements for Optical Information Processing and Computing
Authors: Asthana Praveen , Herbulock Edward , Karim Zaheed , Kyriakakis Chris , Nordin Gregory P. , Tanguay Armand R. 
Published: March 2011

ABSTRACTPhotorefractive materials comprise an important category of electrooptic materials, and are important constituent elements in a wide range of devices designed specifically for use in optical information processing and computing systems. Critical issues affecting the development and applicability of photorefractive materials are examined from the perspective of photonic neural network implementations that incorporate photorefractive volume holographic interconnections.
Applications of Organic Electro-Optic Materials in High Speed
Electronic Processors
Authors: Lipscomb G. F. , Lytel R. S. , Ticknor A. J. , Kenney J. , Eck T. E. Van , Girton D. G. , Binkley E. 
Published: March 2011

ABSTRACTThe exceptional electro-optic properties of poled polymer films, coupled
with the power and flexibility of thin film fabrication and
photolithographic processing, may make possible a new class of integrated
optic systems combining the processing power of VLSI with a dense, high
bandwidth, photonic interconnection and switching network. We report on the
recent development and initial test results of two electro-optic polymer
based integrated optic devices for optical interconnection applications. The
first is an optical railtap for the distribution of many different optical
signals from a single CW laser diode, and the second is a traveling wave
Mach-Zehnder integrated optic modulator, which was modulated at frequencies
up to 20 GHz.
Room-Temperature CW Operation of SQW Lasers on Si Grown with
AiGaAs/AlGaP Intermediate Layers by MoCVD
Authors: Egawa T. , Hayashi Y. , George T. , Soga T. , Jimbo T. , Umeno M. 
Published: March 2011

ABSTRACTThe heterointerfaces of single quantum wells (SQWs) and the characteristics
of SQW lasers on Si substrates grown with Al0.5 Ga0
5As/Al0.55Ga0.45P intermediate layers
(AlGaAs/AlGaP ILs) entirely by MOCVD are reported. The surface morphology
and the heterointerfaces of SQWs grown on Si substrates with the
AlGaAs/AlGaP ILs are smoother than those of the two-step-grown sample. The
two-dimensional growth of the AlGaAs/AlGaP ILs on a Si substrate contributes
to obtain the smooth heterointerface. The excellent lasing characteristics
are obtained by the AlGaAs/AlGaP ILs, which are caused by the smooth
heterointerfaces. The lasers grown with the AlGaAs/AlGaP ILs show the
averaged threshold current density of 1.83 kA/cm2 and the
averaged differential quantum efficiency of 51.9 % under cw condition at
room temperature.