Nov 18, 2014 | Lei Nie, Wenjing Xiang - Hubei University of Technology, Mingxiang Chen, Huajing Li, Quan Chen - Huazhong University of Science and Technology
Performance degradation of packaging material is an important reason for the lifetime reduction of LED. In order to understanding the failure behavior of packaging material, silicone and phosphor were chosen to fabricate LED samples within which an aging test at 125℃ was performed. The result of online luminance measurement showed that LED samples with both silicone and phosphor had the highest luminance decay rate among all test samples because the carbonization of silicone and the consequent outgassing reduced the luminance quickly. The result of the luminance variance with test time was analyzed and an exponential decay model was developed with which the lifetime of LED under high temperature could be estimated....
Publisher: Hubei University of Technology
Nov 13, 2014 | Gregor Langer, Markus Leitgeb - Austria Technologie & Systemtechnik AG, Johann Nicolics, Michael Unger - Vienna University of Technology, Hans Hoschopf, Franz P. Wenzl - Joanneum Research Forschungsgesm.b.H.
With increasing power loss of electrical components, thermal performance of an assembled device becomes one of the most important quality factors in electronic packaging. Due to the rapid advances in semiconductor technology, particularly in the regime of high-power components, the temperature dependence of the long-term reliability is a critical parameter and has to be considered with highest possible care during the design phase (...)
The aim of this paper is to give a short overview about standard thermal solutions like thick copper, thermal vias, plugged vias or metal core based PCBs. Furthermore, attention will be turned on the development of copper filled thermal vias in thin board constructions......
Publisher: Tridonic GmbH & Co KG
Nov 06, 2014 | Hugh Roberts, Sven Lamprecht, Gustavo Ramos, Christian Sebald
This paper summarizes the results of recent investigations to examine the effect of electroless nickel process variations with respect to Pb-free (Sn-3.0Ag-0.5Cu) solder connections. These investigations included both ENIG and NiPd as surface finishes intended for second level interconnects in BGA applications. Process variations that are suspected to weaken solder joint reliability, including treatment time and pH, were used to achieve differences in nickel layer composition. Immersion gold deposits were also varied, but were directly dependent upon the plated nickel characteristics. In contrast to gold, different electroless palladium thicknesses were independently achieved by treatment time adjustments....
Oct 30, 2014 | P. Borgesen, S. Hamasha, M. Obaidat, V. Raghavan, X. Dai; Department of Systems Science & Industrial Engineering, Binghamton University, M. Meilunas, M. Anselm; Universal Instruments Corporation.
The ultimate life of a microelectronics component is often limited by failure of a solder joint due to crack growth through the laminate under a contact pad (cratering), through the intermetallic bond to the pad, or through the solder itself. Whatever the failure mode proper assessments or even relative comparisons of life in service are not possible based on accelerated testing with fixed amplitudes, or random vibration testing, alone. Effects of thermal cycling enhanced precipitate coarsening on the deformation properties can be accounted for by microstructurally adaptive constitutive relations, but separate effects on the rate of recrystallization lead to a break-down in common damage accumulation laws such as Miner's rule. Isothermal cycling of individual solder joints revealed additional effects of amplitude variations on the deformation properties that cannot currently be accounted for directly.
We propose a practical modification to Miner's rule for solder failure to circumvent this problem. Testing of individual solder pads, eliminating effects of the solder properties, still showed variations in cycling amplitude to systematically reduce subsequent acceleration factors for solder pad cratering. General trends, anticipated consequences and remaining research needs are discussed...
Publisher: Universal Instruments
Oct 27, 2014 | Pete Doyon, VP Product Management, Schleuniger, Inc.
A lot of time and effort often goes into finding the right equipment for your facility. Purchasing a new wire cut & strip machine is no different. With so many options, where does one start? Asking these five questions during the decision making process will help ensure you end up with equipment that fits all of your needs. ...
Publisher: Schleuniger, Inc.
Oct 23, 2014 | Dr. Mike Bixenman; Kyzen Corporation, Julie Fields; Technical Devices Company, Eric Camden; Foresite.
The functional reliability of electronic circuits determines the overall reliability of the product in which the final products are used. Market forces including more functionality in smaller components, no-clean lead-free solder technologies, competitive forces and automated assembly create process challenges. Cleanliness under the bottom terminations must be maintained in harsh environments. Residues under components can attract moisture and lead to leakage currents and the potential for electrochemical migration (...)
The purpose of this research study is to evaluate innovative spray and soak methods for removing low residue flux residues and thoroughly rinsing under Bottom Termination and Leadless Components...
Publisher: Kyzen Corporation
Oct 16, 2014 | Rama Hegde, senior member of technical staff; Freescale Semiconductor.
Key points are:
*Long-term storage of BGA & QFP products may be required due to:
* Integrity of EOL products in terms of solderability needs to be verified....
Publisher: Freescale Semiconductor Inc
Oct 09, 2014 | Wilfried Clemens.
Over the last years more and more international newspapers reported in Europe / USA and Japan: "Tunnel train got stuck under the Channel – thousands of people stranded", "Recall of thousands of cars to workshops for control and repair", "Power Failures left households without energy for hours." Very often news like this relate to malfunctions of electric and electronic circuits under adverse conditions or sometimes even in normal operating environment (...)
The presentation will deal with all kinds of aspect of cleaning to ensure the reliability of electronic circuitry in ever changing operation conditions in the most important industrial areas....
Publisher: Kolb Cleaning Technology GmbH
Oct 02, 2014 | Jennifer Nguyen Ranilo Aranda, David Geiger, and Murad Kurwa
Sn3.0Ag0.5Cu (SAC305) is the most popular near eutectic lead-free alloy used in the manufacturing processes. Over the last several years, the price of silver has dramatically increased driving a desire for lower silver alloy alternatives. As the results, there is a significant increase in the number of alternative low/no silver lead-free solder alloys available in the industry recently.
In this paper, we'll present the performance and process capability of various low/no silver alloy solder pastes. Data from printability, wetting test, slump test, solder ball test, voiding, etc… will be discussed and compared with the control SAC305 solder paste. Benefits and concerns of using low/no silver alloy solder paste materials will also be addressed....
Publisher: Flextronics International
Sep 25, 2014 | Joshua J. Markle.
For the past few years there has been a shift in the Lighting Industry that has carried over to the surface mount technology assembly line. What is this shift you may ask? Well it is the LED revolution. This revolution or change in lighting has some very promising results already in practice and many more companies looking to implement the LED technology into their product portfolio's. With a number of companies looking to expand their portfolio to include LED fixtures there has been an increase in the number of companies that have started their own SMT lines, as well as a significant number of contract manufacturers to meet this new industries demands (...)
This presentation will discuss some issues in the pick and place process for LEDs and presents a method to troubleshoot and resolve these issues....
Publisher: Cree, Inc.