bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical Characterization of Photoresist Polymer Coatings as a Function of Processing History
Authors: Tong Kun , Taylor Jeffery F. , Farris Richard J. 
Published: March 2011

AbstractPhotoresist polymer coatings in the film-substratum systems usually generate selfinduced residual stress during processing. It is believed that the residual stress is the driving force for buckling, cracking and delamination of the polymer coatings. Analysis of the residual stress development during processing is of great interest and practical importance.Holographic interferometry technique has been developed for the direct measurements of general 2-dimensional stresses in thin films.[l] It turns out that it is a powerful technique to analyze residual stress development in polymer coatings during processing. By directly measuring the residual stress for each processing stage, the history of residual stress evolution can be closely followed and the residual stresses generated from different origins can be separated. By varying UV curing dosage, thermal curing temperature and the sequence of thermal and UV curing procedures, different residual stresses from various processing conditions can be comprehensively analyzed. Combining these data with mechanical properties of the coating offers valuable information for better understanding of the processing mechanism and enables one to optimize processing conditions for the best product capability.
The Interplay of Thermo-Mechanical Properties in the Growth and Processing of III-V Materials
Authors: Jordan A. S. , Swaminathan V. 
Published: March 2011

AbstractThe thermo-mechanical properties of III-V semiconductors, in general, and of GaAs and InP in particular, are reviewed. They play an important role in many aspects of semiconductor device fabrication starting from the growth of bulk crystals. Dislocation generation in GaAs and InP are discussed with the emphasis on the theoretical and experimental aspects of reducing the dislocation density in these materials. Such mechanical properties as glide systems, critical resolved shear stress and impurity hardening are covered. The effects of dislocations on device performance are illustrated with examples from photonic and electronic devices. Finally, the effect of thermomechanical stresses in the degradation and reliability of GaAs/AlGaAs and InP/InGaAsP based opto-electronic devices is considered.
Presence of Anelastic Strains in High Lead Solders at Ambient and High Temperatures
Authors: Tien J.K. , Attarwala A.I. 
Published: March 2011

AbstractWe had reported last year that cyclically tested Pb/Sn solders of different compositions exhibited a complicating anelastic effect. The storage and recovery of anelastic strains suppresses damaging creep strain from being stored thus causing non-conservative life prediction estimates and results in complications with respect to accelerated testing. These complications were at that time believed to be characteristic of only eutectic solders at near ambient temperatures. We now find that said complications exist for high end Pb solders and at higher temperatures. Strain rate behavior of high lead solders indicate that a different failure mechanism might exist at temperatures where the material exists as a two phase and in regimes where it exists as a solid solution. Experiments conducted to determine the effect of grain size on accelerated cycling indicated that recrystallization of large grains occurs due to cycling at high temperatures. At ambient temperature, which is greater than half the absolute melting temperature of 90/10 Pb/Sn, it was observed that large grains suppress creep.
Stress Dependent Electrical Activation of Implanted Si IN GaAs - A Four Point Bending Study
Authors: Huang J. G. , Jaccodine R. J. , Huang J. H. , Schwarz S. A. , Schwartz C. L. , Bhat R. 
Published: March 2011

AbstractA four point bending experiment was conducted to study the effect of stress on the electrical activation of implanted 29Si in GaAs. The stress distribution in the SiNx-coated GaAs was quantitatively examined. 29Si electrical activation was found to depend strongly on the magnitude of the stress when specimens were annealed under tensile stress; compressive stress had a negligible effect. The n-type GaAs was converted into p-type under excess tensile stress. This stress dependence of electrical activation is attributed to the differences in dislocation characteristics and its interaction with implanted Si under tensile or compressive bending.
A Nonlinear and Time Dependent Finite Element Analysis of Solder Joints in Surface Mounted Components Under Thermal Cycling
Authors: Pao Yi-Hsin , Chen Kuan-Luen , Kuo An-Yu 
Published: March 2011

AbstractA nonlinear and time dependent finite element analysis was performed on two surface mounted electronic devices subjected to thermal cycling. Constitutive equations accounting for both plasticity and creep for 37Pb/63Sn and 90Pb/10Sn solders were assumed and implemented in a finite element program ABAQUS with the aid of a user subroutine. The FE results of 37Pb/63Sn solder joints were in reasonably good agreement with the experimental data by Hall [19]. In the case of 9OPb/1OSn solder in a multilayered transistor stack, the FE results showed the existence of strong peel stress near the free edge of the joint, in addition to the anticipated shear stress. The effect of such peel stress on the crack initiation and growth as a result of thermal cycling was discussed, together with the singular behavior of both shear and peel stresses near the free edge.
Control of Microstructure and Stress in Sputtered Tungsten Thin Films on Silicon
Authors: Kola R.R. , Celler G.K. 
Published: March 2011

AbstractTungsten is attractive for VLSI device metallization because of its high conductivity and resistance to interdiffusion and electromigration. It is also one of the best absorber metals for x-ray lithographic masks. To minimize distortions in an x-ray mask, intrinsic stresses in the absorber films have to be low and reproducible. The physical properties of thin films are very dependent on their microstructure. We present the results of a study of the microstructural evolution and the resulting internal stress of rf sputter-deposited W films as a function of rf power, deposition temperature, and argon pressure. By controlling the nucleating phase and mobility of the adatoms, we have produced W films with low stresses (<±50 MPa). The lattice parameter and the argon content in W films increased with decreasing argon deposition pressure. It was found that a low base pressure (<10−7 torr) is necessary to produce stable α-phase W and to eliminate the metastable β-phase. Stresses in the W films were not affected bysubsequent anneals in vacuum at 200 °C for 50 hrs. In-situ stress measurements indicated stress relaxation by plastic deformation above 300 °C.
Selective Growth of Poly-Diamond Thin Films Using Selective Damaging by Ultrasonic Agitation on a Variety of Substrates
Authors: Ramesham R. , Roppel T. , Ellis C. 
Published: March 2011

AbstractPolycrystalline diamond thin films have been selectively deposited on Si, SiO2, Si3 N4, Ta, Mo, alumina, and sapphire substrates using selective damaging by ultrasonic agitation. Novel processes were developed to selectively damage the polished substrates by ultrasonic agitation. Optical and scanning electron microscopy is used to study selectivity and morphology of as-grown diamond thin films.
Continuous Wetiability Measurement for Solder Reflow
Authors: Melton Cynthia M. , Yarling Susan M. , Raleigh Carl J. 
Published: March 2011

AbstractA quantitative dynamic solder wettability mesurement technique was utilized to evaluate the effects of reflow processing on the wettability parameters associated with solder ball alloys. This technique enables the examination of the final degree of solder wetting and the continuous monitoring of wetting as a function of time during the reflow process under nitrogen atmosphere. An experimental design approach employing a 24 full factorial experiment was formulated to illustrate the use of this measurement technique investigating the final result of wetting. Solder wettability was determined with respect to the contact angle, base diameter and height of the reflowed solder ball alloy. The most significant effect estimates with respect to contact angle were solder flux and pad metallization. Solder ball alloy was found to significantly impact the base diameter and height of the reflowed solder. The effect of solder flux activators and pad metallizations on the subsequent continuous solder wettability wetting rates and amount of molten solder spread of solder ball alloys during reflow were measured. Reflow with a relatively more activated solder flux material was found to enhance the rate of solder wetting of the the pad metallization.
Numerical Simulation & Experimental Investigation of SMT Laser Microsoldering Thermal Process
Authors: Chunqing Wang , Yiyu Qian , Yihong Jiang 
Published: March 2011

AbstractIn this paper,a numerical simulation of thermal process in the SMT laser microsoldering joint has been developed, in which, the influence on thermal process of the factors such as the thermal conductivity variation of solder with temperature, light reflection coefficient of the lead wire surface, and heat exchange on the surface of SMT materials all have been considered. In order to carry this numerical calculation practice and prove it's results,the reflexive characteristic of light wave to the SMT materials has been gauged,and the dynamic temperature process of laser microjoint has been measured by a new experimental method which was invented by the authors.The results of numerical simulation have been borne out by the tests, and the influences of heating parameters on thermal process has been analysed in this paper.The conclusions will be advantageous to the further study of the microjoint quality control in the SMT laser microsoldering.
Mechanisms of Inelastic Deformation and Stress Relaxation in Thin Metallizations Bonded to Hard Substrates
Authors: Korhonen M.A. , Bergesen P. , Li Che-Yu 
Published: March 2011

AbstractThe yield strength of metallic thin films bonded to hard substrates can be significantly higher than is customary for bulk samples of the same metal. This is related to the constrained nature of the deformation. The constrained deformation, as well as the commonly observed crystallographic texture of thin films, places restrictive conditions on the mechanisms of deformation that produce stress relaxation. In narrow aluminum based metallizations used as interconnects in large scale integrated circuits thermal stress induced voiding provides an effective means for stress relaxation. For these interconnects, the stress state is tensile after excursions to higher temperatures; the stresses relax mainly by dislocation glide and grain boundary sliding during the cooldown, while the longer term relaxation is governed by stress-induced voiding and dislocation creep.
Mechanical Modeling of Stress Generation During Cure of Encapsulating Resins
Authors: Lagasse R. R. , Chambers R. S. , Guess T. R. , Plazek D. J. , Bero C. 
Published: March 2011

AbstractWe have developed a numerical model for calculating stresses generated during cure of shrinking encapsulating resins. Mechanical modeling of polymer encapsulated electronic devices usually focusses on stress generated during cooling after cure. The stress developed during cure, due to shrinkage of the encapsulant, is normally neglected. That assumption is valid if both the shear and bulk moduli of the encapsulant at the cure temperature are negligible with respect to the moduli at lower temperatures. Our measurements on a model epoxy encapsulant show that the shear modulus during cure, varying from 0 to 6 MPa, is at least 100 times smaller than that at ambient temperature. In contrast, the bulk modulus at the cure temperature is only 2.5 times smaller. Since the bulk modulus during cure cannot be neglected, significant stress can be produced if volume shrinkage is constrained by a stiff mold or embedded elements. In fact, mechanical failure of encapsulating materials during cure has been evident in some of our experiments. Using measurements of shear and bulk moduli plus volume shrinkage as inputs to a finite element model, we have successfully predicted the shrinkage strains and stresses developed during cure of a model epoxy resin inside a cylindrical tube. Consideration of cure shrinkage stress has led to a process modification that appears to reduce mechanical failures in a real encapsulated device.
Properties Of A Photoimageable Thin Polyimide Film II.
Authors: Maw Taishih , Hopla Richard E. 
Published: March 2011

ABSTRACTThe polylmide synthesized from benzophenonetetracarboxylic dianhydride and alkyl-substituted diamines is inherently photosensitive at ≤365 nm, and a solvent soluble, negative-acting system can be formulated from the fully-imidized resin. The lithographic, thermal, mechanical, and electrical properties of the polyimide films have been characterized. This polyimide film shows good thermal, mechanical, and electrical properties, and a 1:1 aspect ratio is consistently achieved on 10 μm thick films. The thermal properties of the films were determined using TGA and TMA methods. The decomposition temperature was 527°C, the weight loss of the cured film at 350°C in nitrogen was 0.04 %/hour and the thermal expansion coefficient was 37 ppm/°C. The dielectric constant and dissipation factor of the film were 3.0 and 0.003 respectively at 4% humidity. The effects of hard-bake time, hard-bake temperature, nitrogen purge rate during heat treatment, and humidity on the thermal and electrical properties of the thin film were also examined, and are presented here. The rate of weight loss of the cured film increases when the rate of nitrogen purge decreases or when the cure temperature increases. Longer heat treatments resulted in a slight decrease in the CTE and an Increase in the Tg. The electrical properties of the films are dependent both on the humidity during measurement and on the hard-bake temperature.
Electrical Properties Of Thin Polyimide Films Prepared By Ionized Cluster Beam Deposition
Authors: Jung Hyung-Jin , Lee Dong-Heon , Lee Jeon-Kook , Whang Chung-Nam 
Published: March 2011

ABSTRACTThe electrical properties of gold – polyimide - silicon structures were investigated experimentally by capacitance – voltage (C – V) measurement. Polyimide films were deposited on silicon substrate by using ionized cluster beam deposition (ICBD) of PMDA-ODA followed by in-situ thermal curing in N2 atmosphere. The resulting C – V plots show hysteresis, and it was believed to be due to the injection of carriers. The interface trap density is fairly low because of the clean interface provided by ICB technique.
Organo-Soluble, Segmented Rigid-Rod Polyimides: Synthesis and Properties
Authors: Harris F. W. , Hsu S. L. C. , Lee C. J. , Lee B. S. , Arnold F. , Cheng S. Z. D. 
Published: March 2011

ABSTRACTSeveral segmented, rigid-rod polyimides have been prepared that are soluble in organic solvents in their fully imidized form. The polymers were prepared from commercial dianhydrides and 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl (TFMB). Their intrinsic viscosities ranged from 1.0 to 4.9 dL/g. Tough, colorless films could be cast from m-cresol solutions at 100°C. The polymers had glass transition temperatures (Tgs) above 275°C and displayed outstanding thermal and thermo-oxidative stability. Fibers were prepared from the 3,3′,4,4′-tetracarboxybiphenyl dianhydride (BPDA) based polymers that had moduli of 130 GPa and tensile strengths of 3.2 GPa. The thermal expansion coefficients and dielectric constants of thin films (20–25 μm) of the polymers were as low as −2.40×10−6 and 2.5, respectively.
Polyimide Copolymers Containing Various Levels Of The 6F Moiety For High Temperature And Microelectronic Applications
Authors: Haider M. , Chenevey E. , Vora R. H. , Cooper W. , Glick M. , Jaffe M. 
Published: March 2011

ABSTRACTTrifluoromethyl group-containing polyimides not only show extraordinary electrical properties, but they also exhibit excellent long-term thermo-oxidative stability. Among the most thermomechanically stable structural polyimides are those from 6F dianhydride (6FDA) and 6F diamines. The effects of substituting non-fluorine containing monomers such as BTDA, mPDA and 4,4′-DADPS for the hexafluoroisopropylidene monomers on the dielectric, thermo-oxidative, thermal and mechanical properties of the copolymers were studied.
Poly(Enaminonitriles): Novel Materials For Use In Microelectronics
Authors: Moore J. A. , Kim Ji-Heung 
Published: March 2011

ABSTRACTA series of new poly(enaminonitriles) were synthesized by the condensation polymerization of three different bis(chlorodicyano-vinyl) aromatic monomers with various aromatic diamines. These polymers have moderate to high molecular weight with intrinsic viscosities ranging from 0.35 to 0.77 dl/g and form flexible films. These polymers exhibit good solubility in many organic solvents and excellent thermal stability, retaining their weight up to 400 °C in air. Poly(enaminonitriles) undergo ‘curing’ reactions at high temperature (˜300 °C) to provide insoluble, infusible material without emission of volatile by-products. Dielectric constants of these polymers ranged from 3.5 to 5.2 depending on the structure. Their thermal and dielectric properties are correlated to the structures.
Preparation Of Polyimide-Silica Hybrid Films
Authors: Kakimoto Masa-aki , Morikawa Atsushi , Iyoku Yoshitake , Imai Yoshio 
Published: March 2011

ABSTRACTPolyimide-silica hybrid films were successfully prepared by the sol-gel reaction starting from a mixture of tetraethoxysilane (TEOS), a solution ofpolyamic acid in N, N-dimethylacetamide and water of pH 7 and pH 3. The hybrid films were obtained by the hydrolysis-polycondensation of TEOS in the polyamic acid solution, followed by heating at 270°C. Fairly flexible films were obtained for silica contents up to 70 wt%. The films containing less than 8 wt% of silica were yellow and transparent, whereas the films with higher silica contents were yellow and opaque. The density of the silica in the hybrid films was estimated to be 1.65 and 1.69 g/cm3 (pH 7 and pH 3). The29Si nuclear magnetic resonance spectrum indicated that the silica in the films consisted of non-hydroxy, monohydroxy, and dihydroxy siloxane structures. Silica particles with submicron diameter were observed in the hybrid films containing less than 8 wt% silica, whereas larger particle size around 5 μ m in the case of higher silica content. The decomposition temperature of the hybrid films increased with increasing silica content. The glass transition temperature of the hybrid films showed the minimum at 8 wt% of silica content. Tensile properties, such as elongation at break, tensile strength, and tensile modulus also exhibited the same tendency. The linear thermal expansion coefficient of the silica in the hybrid films was estimated to be 1.3 × 10−5 and 0.3 × 10−5 (pH 7 and pH 3), which suggested that the silica had a porous structure.
Vertical-Cavity Surface-Emitting Lasers: Mbe Growth and Optical
Information Processing Applications
Authors: Harbison J. P. , Florez L. T. , Scherer A. , Chang-Hasnain C. J. , Lehmen A. C. Von , Chan W. K. , Clausen E. M. , Orenstein M. , Jewell J. L 
Published: March 2011

ABSTRACTThe basic issues involved in the growth by molecular beam epitaxy (MBE) of
vertical-cavity surface-emitting lasers (VCSELs) are discussed. Successful
VCSEL optical information processing applications demonstrated to date are
discussed, including two-dimensional arrays, holographic memory retrieval,
optical addressing, wavelength division multiplexing, and tunable VCSEL
operation.
Quantum-Well Lasers for High-Speed Optical Information
Processing
Authors: Wu M. C. , Chen Y. K. , Tanbun-Ek T. , Logan R. A. 
Published: March 2011

ABSTRACTMonolithic colliding pulse mode-locked (CPM) multiple quantum well lasers
generating optical pulses as short as 600 femtoseconds are reported. The CPM
laser is built on a single chip of InGaAs/InGaAsP multiple quantum well
laser. The pulse repetition rates are synchronized with an rf synthesizer up
to 40 GHz in hybrid mode-locking scheme. In passive mode-locking scheme, a
record high repetition rate of 350 GHz has been achieved. All the
sub-picosecond pulses obtained have pulse shapes of sech2 and
transform-limited timebandwidth products between 0.30 to 0.34. This new
optical source is very useful for ultra-high speed optical switching and
optical logic in optical fibers, and ultra-long distance optical soliton
transmissions.
AlGaAs/GaAs Double-Heterostructure Optical Waveguide on Si
Substrates
Authors: Yuasa T. , Umeno M. , Sakai S. , Wada N. , Ueta Y. 
Published: March 2011

ABSTRACTAlGaAs/GaAs double-heterostructure (DH) optical waveguides on Si substrates
which is important in future opto-electric integrated circuits (OEICs)
utilizing both Si and GaAs devices is analyzed by the effective index method
and fabricated by metalorganic chemical vapor deposition (MOCVD).The structures contain 0.8-μm-thick GaAs guiding layer sandwiched between
two 1-μm-thick Al0.1Ga0.9 As cladding layers. All the
layers were grown by MOCVD on (100) 2°-off Si substrates by two step method.
A top cladding layer was etched leaving 2-μm wide mesa-stripes. The etched
depth was changed from 0.65 to 0.90 μm. The field profiles were calculated
and measured for 1.3 μm wavelength light. The measured and calculated
profiles agree quite well with each other for all the. waveguides having
different mesa height. This agreement makes us possible to design more
complicated AlGaAs/GaAs waveguides and modulators on Si substrates.
Possibility of a Si-Based Infrared Detector Using
Microcrystalline B-Si-Ge Alloys
Authors: Osaka Y. , KOhno K. , Shresta P. 
Published: March 2011

ABSTRACTMicrocrystalline films of B-Si-Ge alloy have been deposited by the
sputtering of Ge target in atmosphere of SiH4 and
B2H6. Microcrystalline B-Si-Ge alloy/Si
hetero-junction was fabricated on p-type Si(100) wafers with the resistivity
of 1∼10 Ωcm. The barrier height of this Schottky structure was estimated to
be in the range of 0.20∼0.30 eV which can be controlled by inclusion amounts
of boron. The reverse biased Schottky characteristic using the
microcrystalline B-Si-Ge alloy as to the gate shows the avalanche breakdown
by illuminating of 6 μm light.
The Problem of Doping Wide Gap II-VI Compound Semiconductors and
Its Solutions
Authors: Wang W. I. 
Published: March 2011

ABSTRACTWide gap II-VI compound semiconductors are difficult to be doped
amphoterically. After more than thirty years of research in II-VI compound
semiconductors, there does not even exist a satisfatory simultaneous
explanation as to why ZnSe can be easily doped n-type while undoped ZnTe
only exhibits p-type conductivity. In this paper we propose an explanation
based on the III-V/II-VI analogy which for the first time can explain these
phenomena, and provide solutions to the problem of doping II-VI compound
semiconductors.