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Electronics Packaging Manufacturing, IEEE Transactions on

Issue 3 • Date July 2008

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Displaying Results 1 - 18 of 18
  • Table of contents

    Page(s): C1
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  • IEEE Transactions on Electronics Packaging Manufacturing publication information

    Page(s): C2
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  • Gold Embrittlement of Solder Joints in Wafer-Level Chip-Scale Package on Printed Circuit Board With Ni/Au Surface Finish

    Page(s): 185 - 191
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    In this paper, the effect of gold amount on the gold embrittlement of solder balls in wafer-level chip-scale package (WLCSP) CSP 80 is investigated. First, precisely controlled amounts of gold were added artificially to solder balls through a reflow process. It is found that for CSP 80 without Au, after 2000 h of thermal aging at 150 degC, the solder balls still fail in the bulk solder. When Au is incorporated, brittle failure occurs after 1000 and 200 h for CSP 80 with 0.3 wt% and 0.5 wt% of Au, respectively. Detailed inspections on the microstructure reveal that, after the reflow process, fine AuSn4 intermetallic compound (IMC) particles disperse uniformly in the bulk solder. After 200 h at 150 degC, the (Cu,Ni)6Sn5 ternary compound transforms to Cu-Au-Ni-Sn quaternary compound and the IMC at the interface of solder and under bump metallization (UBM) becomes a completely continuous layer. After 1000 hours at 150 degC, two IMC layers, light gray and dark gray, forme at the interface. EDX analysis confirms that the light and dark gray IMC layers are the (Cu,Ni,Au)6Sn5 compound. However, the light gray (Cu,Ni,Au)6Sn5 compound contains a higher amount of Au and a lower amount of Ni, while the dark gray (Cu,Ni,Au)6Sn5 IMC contains a lower amount of Au and a higher amount of Ni. After 2000 h at 150 degC, the two IMC layer structures still exist. View full abstract»

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  • Combined Parameter and Tolerance Design for Quality via Computer Experiment: A Design for Thermoelectric Microactuator

    Page(s): 192 - 201
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    A thermoelectric microactuator is examined with a computer experimental approach based on the asymmetrical thermal expansion of the microstructure with two beams of different widths. Because a typical U-shaped lateral thermoelectric actuator is used, the remaining concerns are the associated parameters and tolerance values that need to be determined. Conventional approaches consider that parameter and tolerance variables are two unconnected controllable variables, with the condition that the analytical functions representing the design of interest are known. A belief that the two variables are unconnected, usually fails to find truly optimal solutions, particularly a belief that the design functions are nonlinear in a complicated design. Assuming that design functions are normally known is a mistake in most cases, especially in the early stage of design. In this regard, a simultaneous parameter and tolerance design accompanying the computer experiment is developed to ensure that true optimization is achieved. The computer experimental approach consists of both a computer simulation and a statistical method. In this paper, the computer simulation is performed with existing computer-aided engineering (CAE) software, and ANSYS, the finite-element method for the solution of coupled 3-D mechanical problems. The statistical method is one of a design experimental approach such as response surface methodology (RSM). The response value is the conformation rate used in measuring product quality for uncertain conditions. This approach provides designers not only with optimal parameter and tolerance values, but also with the importance ranking for the controllable variables of a product. This is particularly important for the evolutionary design processes in an uncertain environment. View full abstract»

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  • Drop-on-Demand Solder Droplet Jetting System for Fabricating Microstructure

    Page(s): 202 - 210
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    The novel drop-on-demand (DOD) solder droplet jetting system, which can be characterized as the non-heat affection of the piezoelectric actuator, the control mechanism of the piston head-to-nozzle distance, and disposable nozzle parts, is devised. This system consists of the piezoelectric actuator, insulator, piston head-to-nozzle distance control apparatus, pressure control unit, and furnace. For the modulation of the droplet size, the distance from piston head-to-nozzle exit can be controlled by using the piston head-to-nozzle distance control apparatus. The working temperature is improved by locating the piezoelectric actuator outside of the furnace and by inserting the insulation block between the print head and the actuator. From a practical point of view, the DOD solder droplet jetting system has a simple structure for easily interchangeable nozzle parts. We derived the equation of the ejected droplet volume as a function of design parameters and operating conditions. The prototype of the DOD solder droplet jetting system was fabricated and the performance was verified. The diameter, volume and velocity of the ejected solder droplet are around 65-150 mum, 140 pl-1.8 nl, and 2.8-4 m/s, respectively. We also experimented with the effect of varying the chamber pressure, piston head-to-nozzle distance, and operating frequency on the ejected droplet diameter and velocity. The high aspect ratio vertical columns and inclined columns were fabricated by using the DOD solder droplet jetting system. View full abstract»

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  • Design and Evaluation of Bioepoxy-Flax Composites for Printed Circuit Boards

    Page(s): 211 - 220
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    Printed circuit boards (PCBs) pose considerable occupational health risks during manufacturing and are a potential source of toxic hazards if improperly disposed at the end of their useful life. Indeed, base materials in current PCBs include epoxy resins, fiberglass, and brominated flame retardants. To improve the environmental performance of PCB manufacturing and disposal, we developed composite designs using a thermosetting matrix based on epoxidized linseed oil, melamine polyphosphate for flame retardance, and woven flax fiber for reinforcement. Analyses of our prototypes using IPC 4101A/24 specification for thick PCB laminates gave acceptable results for thermal, mechanical, and electrical properties, except for wet conditioning or water submersion. To improve moisture resistance, we treated flax fibers with sodium hydroxide and octadecyltrichlorosilane. We find that the improved bioepoxy-flax PCB design is a viable alternative to current PCBs; it has potentially lower environmental impacts, it is cheaper, and it has satisfactory thermal, electrical, and mechanical properties. However, additional improvements in moisture absorption properties may remain needed for commercial applications. View full abstract»

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  • Study of Temperature Parameter in Au–Ag Wire Bonding

    Page(s): 221 - 226
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    The effect of the temperature on bondability and bonding process for wire bonding are investigated. Bondability is characterized by shear bonding strength and bonding process is represented by input and output power of ultrasonic transducer. A laser Doppler vibrometer and Labview software were used to record the velocity, voltage and current of transducer at different temperature settings. A K-type thermocouple sensor was used to measure the bonding temperature. Experimental results show that unsuccessful bonding happens at low temperature, and over bonding appears if the temperature is too high. Only when the temperature is at appropriate settings, can a stable and satisfied bondability be attained. The reason for this experimental observation is analyzed. By using a high resolution transmission electron microscope, the atom diffusion depth of Au-Ag bonding interface was measured and the result is about 200 nm. By using joint time-frequency analysis, the instantaneous characteristics of bonding process were observed completely and clearly. It is found that input and output ultrasonic power vs. time-frequency in a bonding process, including resonance frequency, harmonic components and amplitude of ultrasonic energy, vary along with the change of temperature settings. View full abstract»

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  • Solder Joint Characteristics and Reliability of Lead-Free Area Array Packages Assembled at Various Tin–Lead Soldering Process Conditions

    Page(s): 227 - 239
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    This paper presents a comprehensive study on the effects of critical process conditions on solder joint metallurgy and reliability of mixed-alloy solder joints. The solder joint metallurgy of mixed alloys was characterized and the lead distribution through the solder joint was analyzed, for different package types and under various process conditions. The results showed that the solder paste amount (ultimately the tin percentage (Sn%) in the alloy) and the reflow temperature play critical roles in the mixed-alloy assembly, both in terms of compositional homogeneity and voiding. The reliability of mixed-alloy solder joints was then studied at various process conditions, under different thermal and mechanical stress environments. The study revealed that the sensitivity of the reliability of the mixed-alloy solder joints to the process condition depends on the type of environmental loading. View full abstract»

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  • Detection of Thermal Cycling-Induced Failures in RF/Microwave BGA Assemblies

    Page(s): 240 - 247
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    The purpose of this paper was to investigate the effect of thermal cycling on the high-frequency behavior of ball grid array (BGA) interconnection structures. In order to characterize the applicability of RF measurements in predicting interconnection breakdown, a broadband BGA transition structure between a radio frequency printed wiring board (RF-PWB) and a ceramic module was fabricated. In addition to basic assemblies consisting of two BGA transitions between the module and substrate, the designed transition was applied in a passband filter module to demonstrate the effect of thermal cycling on the performance of a practical device, as well. The BGA test modules mounted on the PWBs were exposed to thermal cycling testing over a temperature range of -40degC to + 125degC. To detect interconnection failures induced by cyclic thermal stresses, both dc resistance and scattering parameter measurements were performed on the test assemblies at specific intervals. Parallel to the electrical measurements, crack propagation in the vicinity of the BGA transition structure was investigated using scanning acoustic microscopy (SAM). Moreover, scanning electron microscopy (SEM) was used to determine the failure mechanisms of the test assemblies. Degradation of the signal transmission characteristics of the basic assemblies was first observed at higher microwave frequencies as an increase in signal return loss (|S11|) and/or a change in its phase. The effect of TCT on the filter assembly was more constant and clearer to observe in the phase than in the magnitude of S11 in the passband. The dc resistance measurements showed no indication of degradation in any of the tested assemblies. View full abstract»

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  • Dynamic Characteristics of a New Jetting Dispenser Driven by Piezostack Actuator

    Page(s): 248 - 259
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    This paper proposes a new type of jetting dispenser driven by a piezostack actuator. After describing structural components of the dispensing mechanism and operating principle, a dynamic model of the dispenser is analytically formulated by considering dynamic behaviors of the piezostack-piston head and the ball-needle. The inelastic impact between the ball-needle and the ball-seat during dispensing process is also considered in the modeling. An analytical fluid-solid interaction model is then derived by integrating the dynamic behavior of the dispensing fluid. Dispensing performances such as dot size and flow rate are evaluated under various frequencies and amplitudes of the sinusoidal driving voltage applied to the piezostack actuator. View full abstract»

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  • Processing of Silvar for MIC Packaging Applications

    Page(s): 260 - 265
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    Materials with high thermal conductivity and thermal expansion coefficient matching with that of GaAs are being used for packaging high-density microwave integrated circuits (MICs) due to their ability of faster heat dissipation. Powder metallurgy (P/M) has emerged as a promising technique for the processing of metal matrix composites (MMCs) in satellite applications such as thermal management materials. Individual components in these composites must retain their metallurgical identity. The present study investigates the processing of silvar (Fe-Ni-Co-Ag) alloys for thermal management materials. For these silvar alloys, composition was varied by varying the silver content from 15 to 35 wt.%. The compacts were pressed at 400 and 600 MPa and sintered/infiltrated at 1100degC, 1150degC,and 1225degC. Quantitative metallographic measurements were performed on all sample and the results were discussed. It was observed that all samples were sintered without any shape distortion. Microstructural evaluation reveals that higher compaction pressure resulted in highly contiguous structure. In spite of density differences between constituents, none of the alloys showed segregation. Coefficient of thermal expansion (CTE) values of the liquid phase sintered composites is near to the values obtained by rule of mixtures. View full abstract»

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  • Table of contents

    Page(s): 266 - 267
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  • Table of contents

    Page(s): 268 - 269
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    Page(s): 270
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    Page(s): 271
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    Page(s): 272
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  • IEEE Components, Packaging, and Manufacturing Technology Society Information for authors

    Page(s): C3
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  • IEEE Components, Packaging, and Manufacturing Technology Society Information

    Page(s): C4
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Aims & Scope

IEEE Transactions on Electronics Packaging Manufacturing addresses design for manufacturability, cost and process modeling, process control and automation, factory analysis and improvement, information systems, statistical methods, environmentally friendly processing, and computer-integrated manufacturing for the production of electronic assemblies and products.

 

This Transaction ceased production in 2010. The current publication is titled IEEE Transactions on Components, Packaging, and Manufacturing Technology.

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Meet Our Editors

Editor-in-Chief
R. Wayne Johnson
Auburn University