Wiring Assemblies Research Articles

Damage Initiation and Propagation in Voided Joints: Modeling and Experiment

This study examines damage initiation and propagation in solder joints with voids, under thermomechanical cyclic loading. An accelerated thermal cycling test is conducted on printed wiring assemblies (PWAs) containing 256 input/output (I/O) plastic ball grid arrays (PBGAs) with voided solder joints. Destructive and nondestructive failure analyses of the solder balls are used to detect the presence of voids and to relate the extent of damage propagation to the number of thermal cycles. Particular cases of voided and damaged joints are selected from these tests, to guide the development of a strategy for modeling damage propagation, using a three dimensional global-local finite element analysis (FEA). The displacement results of the global FEA at the top and bottom of the selected solder balls are used as the boundary conditions in a local FEA model, which focuses on the details of damage initiation and propagation in the individual solder ball. The local model is error seeded with voids based on cases selected in experiment. The damage propagation rate is monitored for all the cases. The technique used to quantify cyclic creep-fatigue damage is a continuum model based on energy partitioning. A method of successive initiation is used to model the growth and propagation of damage in the selected case studies. The modeling approach is qualitatively verified using the results of the accelerated thermal cycling test. The verified modeling technique described above is then used for parametric study of the durability of voided solder balls in a ChipArray Thin Core BGA with 132 I/O (CTBGA132) assemblies, under thermal cycling. The critical solder ball in the package is selected and is error seeded with voids with different sizes and various distances from damage initiation site. The results show that voids in general are not detrimental to thermal cycling durability of the CTBGA132 assembly, except when a large portion of the damage propagation path is covered with voids. Small voids can arrest the damage propagation, but generally do not provide a significant increase in durability because the damage zone deflects around the void and also continues to propagate from other critical regions in the solder ball.

Particle patterning using fluidics and electric fields

Electric-field manipulation of micro-particles in suspension can create patterns via a number of particle forces and fluid flows. These effects are assessed for their suitability for down-scaling to form nano-patterns such as may be incorporated into structured nano-composites. Consideration is given not only to the assembly of field-aligned chains or wires, but also to methods that can give cross-field assembly and even 2-D patterns or crystals. Dielectrophoresis is often the dominant driving force behind particle assembly, but other dipole-dipole interactions and also electrically-driven fluid flows are increasingly recognized as significant or dominant. Orientation of non-spherical particles in frequency-selectable directions is also possible. Estimates for the threshold field strengths required for using these effects to handle nano-particles are considered. Finally the use of media with modified permittivity to increase the field-induced forces or to optimize the selectivity of particle incorporation is discussed.

Generalized gradient-augmented harmonic Fourier beads method with multiple atomic and/or center-of-mass positional restraints

We describe a generalization of the gradient-augmented harmonic Fourier beads method for finding minimum free-energy transition path ensembles and similarly minimum potential energy paths to allow positional restraints on the centers of mass of selected atoms. The generalized gradient-augmented harmonic Fourier beads (ggaHFB) method further extends the scope of the HFB methodology to studying molecule transport across various mobile phases such as lipid membranes. Furthermore, the new implementation improves the applicability of the HFB method to studies of ligand binding, protein folding, and enzyme catalysis as well as modeling equilibrium pulling experiments. Like its predecessor, the ggaHFB method provides accurate energy profiles along the specified paths and in certain simple cases avoids the need for path optimization. The utility of the ggaHFB method is demonstrated with an application to the water permeation through a single-wall (5,5) carbon nanotube with a diameter of 6.78 A and length of 16.0 A. We provide a simple rationale as to why water enters the hydrophobic nanotube and why it does so in pulses and in wire assembly.

Template-Grown NiFe/Cu/NiFe Nanowires for Spin Transfer Devices

We have developed a new reliable method combining template synthesis and nanolithography-based contacting technique to elaborate current perpendicular-to-plane giant magnetoresistance spin valve nanowires, which are very promising for the exploration of electrical spin transfer phenomena. The method allows the electrical connection of one single nanowire in a large assembly of wires embedded in anodic porous alumina supported on Si substrate with diameters and periodicities to be controllable to a large extent. Both magnetic excitations and switching phenomena driven by a spin-polarized current were clearly demonstrated in our electrodeposited NiFe/Cu/ NiFe trilayer nanowires. This novel approach promises to be of strong interest for subsequent fabrication of phase-locked arrays of spin transfer nano-oscillators with increased output power for microwave applications.

Colloidal microstructures, transport, and impedance properties within interfacial microelectrodes

The authors report in situ measurements of the reversible, electric field mediated assembly of colloidal gold microstructures and their associated impedance properties on surfaces between planar gold film microelectrodes. Video optical microscopy is used to monitor the assembly of wires and locally concentrated configurations having variable resistances and capacitances. A scaling analysis of dominant electrokinetic transport mechanisms at different electric field amplitudes and frequencies is consistent with the observed steady-state microstructures. Impedance spectra are fit to equivalent circuits with elements directly connected to physical characteristics of the microelectronic/fluidic device components and different particle microstructures.

Assembly of nanosize metallic particles and molecular wires on electrode surfaces

This article highlights recent developments in the assembly of nanosize materials on electrode surfaces. A brief historical background of the field is given, followed by a selection of topics of particular current interest. We focus especially on the assembly of nanosize metallic particles and molecular wires on gold and silicon electrode surfaces. The fabrication, properties, and characteristics of functional nanostructured biointerfaces on electrode surfaces are also described.

An experimental approach to characterize rate-dependent failure envelopes and failure site transitions in surface mount assemblies

This paper presents an experimental approach to identify the fatigue failure envelopes for solder damage in Printed Wiring Assemblies (PWAs) subjected to dynamic loading. An empirical, rate-dependent, power-law durability model, motivated by mechanistic considerations, is proposed to characterize the failure envelopes in terms of PWA flexural strain and strain rate, as damage metrics. It is further shown that there are critical combinations of these damage parameters, beyond which the failure site changes from the solder to other locations on the PWA. A case study, using a simple PWA specimen containing a single area array component, is presented to demonstrate the proposed approach. Under certain loading conditions, the failure site changes from the bulk solder to the Cu-trace/FR4 interface. The proposed durability model is shown to successfully describe the solder damage failure envelopes. The concept of a “Failure Map” is shown to provide a suitable framework to quantify the durability of the solder interconnect, determine its failure envelope, and identify the failure transition zone of the specimen. The applicability of the proposed technique for comparing the durability of different packaging styles and for developing design guidelines for PWAs subjected to dynamic loading (for example: drop) is discussed.

Test methodology for durability estimation of surface mount interconnects under drop testing conditions

This paper presents a generic methodology to determine the durability of surface mount interconnects in electronic assemblies, under drop loading conditions. Damage accumulated in the interconnects due to repeated drops is quantified in terms of local Printed Wiring Assembly (PWA) response (flexural strain, strain rate, acceleration, number of flexural cycles), rather than the loading (total impact energy, orientation and number of drops). The advantage is that the results are more generic and can be extrapolated to different assemblies and different loading/orientation conditions. A damage estimation model, based on the observed failure mechanism and mode, is used to determine the durability of the surface mount interconnects under the applied loading history. The same model can be used to extrapolate the results to field conditions. A case study, using a simple specimen, is presented to demonstrate the proposed methodology. Failures are observed in the interfacial intermetallic layer of the component bond pad in the corner solder joint. The generality of the method is demonstrated by calibrating the model constants with in-plane drop tests and then successfully predicting the durability for an out-of-plane drop test. Thus, the approach and model constants are shown to be independent of impact orientation and boundary conditions.

Long-range interfacial electron transfer of metalloproteins based on molecular wiring assemblies

We address some physical features associated with long-range interfacial electron transfer (ET) of metalloproteins in both electrochemical and electrochemical scanning tunneling microscopy (ECSTM) configurations, which offer a brief foundation for understanding of the ET mechanisms. These features are illustrated experimentally by new developments of two systems with the blue copper protein azurin and enzyme nitrite reductase as model metalloproteins. Azurin and nitrite reductase were assembled on Au(111) surfaces by molecular wiring to establish effective electronic coupling between the redox centers in the proteins and the electrode surface for ET and biological electrocatalysis. With such assemblies, interfacial ET proceeds through chemically defined and well oriented sites and parallels biological ET. In the case of azurin, the ET properties can be characterized comprehensively and even down to the single-molecule level with direct observation of redox-gated electron tunnelling resonance. Molecular wiring using a pi-conjugated thiol is suitable for assembling monolayers of the enzyme with catalytic activity well-retained. The catalytic mechanism involves multiple-ET steps including both intramolecular and interfacial processes. Interestingly, ET appears to exhibit a substrate-gated pattern observed preliminarily in both voltammetry and ECSTM.

Partitioning and Assembly of Metal Particles and Their Bioconjugates in Aqueous Two-Phase Systems

The behavior of metal nanospheres and nanowires and their bioconjugates in aqueous two-phase systems (ATPS) is described. The ATPS used in this work comprised poly(ethylene glycol) (PEG), dextran, and water or aqueous buffer. Au and Ag nanospheres less than 100 nm in diameter partition between the PEG-rich and dextran-rich phases on the basis of their surface chemistry and can be separated on this basis. Larger Au nanospheres and wires accumulate at the interface between the two aqueous phases. The influence of polymer molecular weight and concentration on interfacial assembly of Au wires is described. DNA-derivatized nanowires at the aqueous/aqueous interface retain the ability to selectively bind to fluorescent complementary DNA. In addition, Au nanoparticles have been bound to Au wires via selective DNA hybridization at the ATPS interface. Transmission electron microscopy and thermal denaturation experiments confirm that DNA-driven assembly is responsible for the formation of the nanosphere/wire assemblies. These results demonstrate the biocompatibility of the two-phase interface and point to future use as scaffolding in biorecognition-driven assembly.

Solderability testing of Sn-Ag-XCu Pb-free solders on copper and Au-Ni-plated kovar substrates

Solderability was evaluated for four Pb-free alloys: 95.5Sn-4.3Ag-0.2Cu (wt.%), 95.5Sn-4.0Ag-0.5Cu, 95.5Sn-3.9Ag-0.6Cu, and 95.5Sn-3.8Ag-0.7Cu on oxygen-free electronic grade (OFE) Cu and Au-Ni plated Kovar substrates. The solderability metric was the contact angle, θc, as determined by the meniscometer/wetting balance technique. Tests were performed at 230°C, 245°C, and 260°C using rosin-based, mildly activated (RMA) flux, a rosin-based (R) flux, and a low-solids (LS) flux. The Pb-free solders exhibited acceptable to poor solderability (35°<θc<60°) on Cu with the RMA flux. Nonwetting occurred in most tests using the R flux. Wetting was observed with the LS flux, but only at 245°C and 260°C and with high contact angles. The solderability of the Pb-free solders improved at all test temperatures on the Au-Ni plated Kovar substrate when using the RMA flux (30°<θc<50°). Wetting was observed with the R flux (35°<θc<60°) and LS flux (50°<θc<85°) for all temperatures. The Pb-free solders had generally lower wetting rates and longer wetting times on Cu than the 63Sn-37Pb solder. The wetting rate and wetting time data were superior on the Au-Ni plated Kovar substrates. In general, solderability, as measured by θc along with the wetting rate and wetting time, did not exhibit a consistent dependence on the composition of the Sn-Ag-XCu (X=0.2, 0.5, 0.6, and 0.7) alloys. The better performers were 95.5Sn-3.9Ag-0.6Cu alloy with the RMA flux (both Cu and Au-Ni plated Kovar) and 95.5Sn-3.8Ag-0.7Cu with the R and LS fluxes (Au-Ni-Kovar, only). The solder-flux interfacial tension, γLF, had a significant impact on the θc values. The magnitudes of the contact angle θc suggested that the four Pb-free solders would experience higher solderability defect counts at the printed wiring assembly level.

Carlisle Companies Inc.

AbstractRubber Products (MIC: 11.6 SIC: 3011 NAIC:326211)Carlisle is a manufacturing company. The Industrial Components segment manufactures non‐automotive tires, wheels, transmission belts and accessories. Co. produces rubber and plastic automotive components and roofing membranes and FleeceBACK™ sheeting for flat roofs in its Automotive Components and Construction Materials segments. The Specialty Products segment manufactures heavy‐duty friction and braking systems for trucks and heavy equipment. The General Industry produces aerospace wire, electronic cable and cable assemblies and interconnects, plastic foodservice permanentware and refrigerated truck bodies. The Transportation Products segment produces high‐payload trailers and dump bodies.

Carlisle Companies Inc.

Mergent's Dividend AchieversVolume 2, Issue 2 p. 46-46 U.S. Company Report Carlisle Companies Inc.† First published: 22 April 2005 https://doi.org/10.1002/div.2217 † Contact: : Stephen P. Munn — Chmn. Address: : 13925 Ballantyne Corporate Place, Suite 400, Charlotte, NC 28277 Web Site: : www.carlisle.com AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract Rubber Products (MIC: 11.6 SIC: 011 NAIC: 26211) Carlisle is a manufacturing company. The Industrial Components segment manufactures non-automotive tires, wheels, transmission belts and accessories. Co. produces rubber and plastic automotive components and roofing membranes and FleeceBACK™ sheeting for flat roofs in its Automotive Components and Construction Materials segments. The Specialty Products segment manufactures heavy-duty friction and braking systems for trucks and heavy equipment. The General Industry produces aerospace wire, electronic cable and cable assemblies and interconnects, plastic foodservice permanentware and refrigerated truck bodies. The Transportation Products segment produces high-payload trailers and dump bodies. Volume2, Issue2Spring 2005Pages 46-46 RelatedInformation

The impact of energy band diagram and inhomogeneous broadening on the optical differential gain in nanostructure lasers

We present a general theoretical model for the optical differential gain in semiconductor lasers. The model describes self assembly quantum dots (QDs), self assembly quantum wires (QWRs) and single quantum-well lasers. We have introduced the inhomogeneous broadening due to size fluctuations in the assembly cases. At each dimensionality, we have considered the carrier populations in the excited states and in the reservoirs, where conduction and valence bands are treated separately. We show that for room temperature operation the differential gain reduction due to increased size inhomogeneity is more pronounced in QDs than in QWRs. We show this reduction to be smaller than the one-order reduction attributed to state filling in conventional dot and wire assemblies operating at room temperature. The integration prefactor coefficient of the differential gain in zero-dimensional cases exceed one- and two-dimensional coefficients only for low temperatures where the homogenous broadening is considerably smaller than the thermal energy. The differential gain of QDs, QWRs, and compressively strained single quantum-well lasers operating at room temperature and close to equilibrium is nearly the same.

Self-consistent rate equations of self-assembly quantum wire lasers

We describe a detailed model for the dynamical and spectral properties of quantum dash (quantum wire assembly) lasers. We use a self-consistent semiclassical theory for a multimode laser field which interacts with an inhomogeneously broadened assembly of quantum wires via the quantum mechanical radiation-matter interaction. Our comprehensive coupled equations are spectrally resolved enabling to study accurately the effect of the gain inhomogeneity. Carrier-carrier and carrier-phonon scattering are also included. We highlight the effective capture rate which is determined by the ratio between the number of states in the reservoir and in the assembly, the energetic region into which carriers are captured and the width of the inhomogeneously broadened gain. Specifically, we demonstrate that a large number of states ratio lowers both the linear optical differential gain and the nonlinear gain coefficient. We show that gain suppression dominates when a realistic energy range into which capture takes place is considered as well as for small number of states ratios. In addition, we show that the width of the inhomogeneous broadening plays a relatively small role. We conclude that the differential gain and nonlinear damping can not be optimized simultaneously. These results point therefore to the clear advantages offered by laser structures which employ non conventional carrier injection schemes such as tunnelling barrier or n-type /spl delta/-doping regions.

Carlisle Companies Inc.

AbstractRubber Products (MIC: 11.6 SIC: 3011 NAIC:326211)Carlisle is a manufacturing company. The Industrial Components segment manufactures non‐automotive tires, wheels, transmission belts and accessories. Co. produces rubber and plastic automotive components and roofing membranes and FleeceBACK™ sheeting for flat roofs in its Automotive Components and Construction Materials segments. The Specialty Products segment manufactures heavy‐duty friction and braking systems for trucks and heavy equipment. The General Industry produces aerospace wire, electronic cable and cable assemblies and interconnects, plastic foodservice permanentware and refrigerated truck bodies. The Transportation Products segment produces high‐payload trailers and dump bodies.

Carlisle Companies Inc.

AbstractRubber Products (MIC: 11.6 SIC: 3011 NAIC:326211)Carlisle is a manufacturing company. The Industrial Components segment manufactures non‐automotive tires, wheels, transmission belts and accessories. Co. produces rubber and plastic automotive components and roofing membranes and FleeceBACK™sheeting for flat roofs in its Automotive Components and Construction Materials segments. The Specialty Products segment manufactures heavy‐duty friction and braking systems for trucks and heavy equipment. The General Industry produces aerospace wire, electronic cable and cable assemblies and interconnects, plastic foodservice permanentware and refrigerated truck bodies. The Transportation Products segment produces high‐payload trailers and dump bodies.

On the nature of quantum dash structures

We describe a theoretical model for the linear optical gain properties of a quantum wire assembly and compare it to the well known case of a quantum dot assembly. We also present a technique to analyze the gain of an optical amplifier using bias dependent room temperature amplified spontaneous emission spectra. Employing this procedure in conjunction with the theoretical gain model, we demonstrate that InAs/InP quantum dash structures have quantum-wire-like characteristics. The procedure was used to extract the net gain coefficient, the differential gain, and the relative current component contributing to radiative recombination.

Synthesis and patterning of nanostructures of (almost) anything on anything

A necessary and very challenging condition for progress in nanoscience is being able to synthesize the requisite material. While there has been substantial success for some materials, one would like to develop protocols to fabricate structures of a wide variety of materials on an equally wide range of supports, preferably with size selection and the ability to pattern on large areas at low cost. The paper by Kerner and Asscher in this issue [1] is significant because it shows how at least some of those conditions can be satisfied in a novel and creative way. Building on the techniques of surface science, many researchers have focused on physical vapor deposition and the subsequent assembly of 1D wires, 2D islands, and 3D clusters. The problem, of course, is that Nature provides rather stringent rules that prevent the spontaneous assembly of 3D structures for all but a few materials. In particular, 3D growth will occur only if the adatoms interact only weakly with the surface but strongly with one another, with details dictated by surface and interface energies. A technique was developed a few years ago that by-passed these rules, termed buffer-layer-assistedgrowth (BLAG) [2–4], and the paper by Kerner and Asscher combines this technique with laser induced thermal desorption to form patterns in a novel and potentially important way. The idea behind buffer layer assisted growth is remarkably simple, as depicted in Fig. 1. The buffer layer replaces adatom–substrate interactions with very weak adatom–buffer interactions so that balling-up occurs out of contact with the substrate. The buffer must subsequently be removed so that the clusters are delivered in the ultimate of soft landings to the substrate where wetting is frustrated by kinetics. While there

DNA-templated assembly of nanoscale wires and protein-functionalized nanogap contacts

The use of DNA to template the assembly of nanoscale wires and protein-functionalized nanogap contacts is described: Specifically, the use of DNA to template the assembly of gold nanowires between conventionally patterned gold contacts on a silicon wafer substrate. Also described is the use of DNA to template the assembly of protein-functionalized nanogap gold contacts on a silicon wafer substrate. Of particular significance is the finding that suitably modified gold nanoparticles recognize and bind selectively the protein-functionalized nanogap and are localized there.