Apr 11, 2014 | Dr. Mary Liu and Dr. Wusheng Yin
In order to meet the increasing demand of device miniaturization, high speed, more memory, more function, low cost, and more flexibility in device design and manufacturing chain, underfilling has increasingly become an essential process for the good reliability of electronic devices. Filled capillary underfill has been selected for use in package-level where there is large thermal stress caused by CTE mismatch issue, but the underfill is usually not reworkable. Unfilled capillary underfill has been used for board-level application such as BGA/CSP, POP, WL-CSP where there is need for mechanical shock resistance, the underfill is usually reworkable....
Publisher: YINCAE Advanced Materials, LLC.
Apr 10, 2014 | Alexander L Carrere.
This paper is meant to be a guide and a reference to new and old members alike who wish to know about, understand, and improve on the decisions made and processes implemented to build the current solar panels. The following paragraphs in the introduction will lay out background information on solar panels and cube satellites. This entire document was written with the idea that the reader will be able to follow the decisions made to construct the solar panels and then with this knowledge find areas of the project for improvement....
Publisher: iSAT Group
Apr 03, 2014 | Nicolas Monnereau, Fabrice Caignet, David Trémouilles, Nicolas Nolhier, Marise Bafleur.
A system level modeling methodology is presented and validated on a simple case. It allows precise simulations of electrostatic discharge (ESD) stress propagation on a printed circuit board (PCB). The proposed model includes the integrated circuit (IC) ESD protection network, IC package, PCB lines, passives components, and externals elements. The impact of an external component on the ESD propagation paths into an IC is demonstrated. Resulting current and voltage waveforms are analyzed to highlight the interactions between all the elements of an operating PCB. A precise measurement technique was designed and used to compare with the simulation results. The model proposed in this paper is able to predict, with good accuracy, the propagation of currents and voltages into the whole system during ESD stress. It might be used to understand why failures occur and how to fix them with the most suitable solution....
Piscataway, New Jersey, United States
IEEE is the world's largest professional association dedicated to advancing technological innovation and excellence for the benefit of humanity.
Mar 27, 2014 | P.J. Duchi, Anne-Marie Laugt, Marie Verdier, G.Aabidh.
Because of the phase out of CFC's and HCFC's, standard solder pastes and fluxes evolved from RA and RMA fluxes, to No-Clean, to low residue No-Clean, to very low residue No-Clean. Many companies came out with their cleaning solutions, aqueous and semi-aqueous, with each product release being more innovative than the previous one. Unfortunately for most of the suppliers of cleaners, two other trends appeared; lead-free soldering and the progressive miniaturization of electronic devices....
Publisher: Inventec Performance Chemicals
Mar 27, 2014 | Richard Puthota Director – Business Development & CTS India & Africa, Cookson Electronics
The surface finish you select will have a large influence on quality, reliability and cost. It is a complex decision that impacts many areas of the business. Select a finish that optimal for the business (and not just one function). Know that there are engineering tricks to improve on weak areas of each finish. Stay current in this field because new developments continue to be made....
Publisher: Cookson Electronics
Mar 27, 2014 | Joe Faruqui
Data bus in computer terminology is a communication system that helps in transferring data between components within a computer, or between separate computers. Know more about data bus components and advancements in data bus technology by reading this article....
Publisher: Just Connectors
Mar 20, 2014 | Dipl.-Ing. Helmut Leicht; Andreas Thumm - IBL-Löttechnik GmbH.
In the beginning of SMT, Vapor Phase Soldering was the preferred reflow soldering technology because of its excellent heat transfer capabilities. There were also some disadvantages like fast temperature rise, nearly no influence on the temperature profiles and high costs. So the use of Vapor Phase Soldering was reduced to special applications with high mass or complex boards in low numbers (e.g. for military or aerospace use)....
Publisher: IBL - Löttechnik GmbH
Mar 13, 2014 | Budapest University of Technology and Economics Department of Electronics Technology
A student competition paper at Budapest University of Technology And Economics, Department of Electronics Technology gives background, covers stencil design and discusses stencils intended for pin in paste application. The stencil applied for depositing the solder paste is a thin, 75–200 µm thick metal foil, on which apertures are formed according to the solder pads on the printed circuit board. Stencil printing provides a fast, mass solder paste deposition process; relatively expensive, appropriate and recommended for mass production....
Mar 06, 2014 | Jasbir Bath, Roberto Garcia - Christopher Associates Inc. Noriyoshi Uchida, Hajime Takahashi, Gordon Clark, Manabu Itoh - Koki Solder
Over the last few years, there has been an increase in the rate of Head-in-Pillow component soldering defects which interrupts the merger of the BGA/CSP component solder spheres with the molten solder paste during reflow. The issue has occurred across a broad segment of industries including consumer, telecom and military. There are many reasons for this issue such as warpage issues of the component or board, ball co-planarity issues for BGA/CSP components and non-wetting of the component based on contamination or excessive oxidation of the component coating. The issue has been found to occur not only on lead-free soldered assemblies where the increased soldering temperatures may give rise to increase component/board warpage but also on tin-lead soldered assemblies....
Publisher: Christopher Associates Inc.
Feb 27, 2014 | Dr. Mary Liu and Dr. Wusheng Yin
Silicon dioxide is normally used as filler in underfill. The thermal conductivity of underfill is less than 1 w/mk, which is not able to meet the current flip chip application requirements such as 3D stacked multi-chips packaging. No matter which direction the heat will be dissipated through PCB or chip, the heat has to pass through the underfill in 3D stacked chips. Therefore the increase of thermal conductivity of underfill can significantly enhance the reliability of electronic devices, particularly in 3D package devices...
Publisher: YINCAE Advanced Materials, LLC.
Feb 20, 2014 | Bhanu Sood and Diganta Das
In this chapter, we discuss the type of parts used to create counterfeits and the defects/degradations inherent in these parts due to the nature of the sources they come from, proposed inspection standards, and limitations of these standards. The processes used to modify the packaging of these parts to create counterfeits are then discussed along with the traces left behind from each of the processes. We then present a systematic methodology for detecting signs of possible part modifications to determine the risk of a part or part lot being counterfeit....
College Park, Maryland, United States
The largest electronic products research center focused on electronics reliability, is dedicated to providing a knowledge and resource base to support the development of competitive electronic components, products and systems.
Feb 13, 2014 | Albert Chen.
The high speed transmission applications in the electronic product become inevitable developing trend. The signal integrity becomes the most important issue in the electronics industry. The material suppliers, PCB manufacturers, OEM designers commonly face the serious issue "how to keep signal integrity operated in the high speed transmission" for the modern electronic application nowadays...
Publisher: Elite Material Co., Ltd.
Feb 06, 2014 | Chris Nash, Technical Support Engineer, Eric Bastow, Senior Technical Support Engineer; Indium Corporation.
Many electronics manufacturers perform SIR testing to evaluate solder materials and sometimes the results they obtain differ significantly from those stated by the solder material provider. The difference in the results is typically the result of SIR coupon preparation. This paper will discuss the issue of SIR coupon preparation, board cleaning techniques, and how board cleanliness directly affects SIR results....
Publisher: Indium Corporation
Jan 30, 2014 | Andreas Thumm
As of today, the electronic industry is aware of the requirements for their products to be lead free. All components are typically available in lead free quality. This comprises packages like BGAs with BGA solder balls to PCB board finishes like HASL. The suppliers are providing everything that is needed. It is harder to get the old tin leaded (SnPb) components for new applications today, than lead free ones.
So why has not everybody changed over fully yet and how can the challenges be overcome?
A big concern in this transition process is reflow soldering. The process temperatures for lead free applications became much higher. Related with this is more stress for all the components. It affects the quality and reliability of the electronic units and products......
Publisher: IBL - Löttechnik GmbH
Jan 23, 2014 | Martin K. Anselm, Ph.D. and Brian Roggeman Universal Instruments Corp.
As reliability requirements increase, especially for defense and aerospace applications, the need to characterize components used in electronic assembly also increases. OEM and EMS companies look to perform characterizations as early as possible in the process to be able to limit quality related issues and improve both assembly yields and ultimate device reliability. In terms of BGA devices, higher stress conditions, RoHS compatible materials and increased package densities tend to cause premature failures in intermetallic layers. Therefore it is necessary to have a quantitative and qualitative test methodology to address these interfaces....
Publisher: Universal Instruments
Jan 16, 2014 | Brian Czaplicki, Director, Technical Marketing Programs, Air Vac Engineering Co., Inc.
BGA Rework is now largely mature, although new supplemental processes that provide improved process control such as Solder Paste Dipping and Non-Contact Site Cleaning can now be integrated into existing processes if the rework technology that is used allows. So what are the next set of challenges that will need to be addressed in regard to Area Array and SMT Rework? The International Electronics Manufacturing Initiative or iNEMI has recently published its 2013 Technology Roadmap for the global electronics industry which includes a section dedicated specifically to rework and repair. Of particular interest and importance is iNEMI’s gap analysis which identifies future specific gaps and challenges that will result from such factors as government regulations, disruptive technologies and new product requirements....
Publisher: Air-Vac Engineering Co., Inc.
Seymour, Connecticut, United States
Air-Vac is committed to producing the highest quality rework/repair, selective soldering/desoldering and assembly systems designed with the capability and flexibility required to meet changing customer and industry requirements.
Jan 09, 2014 | Hikmat Chammas
Embedded Passive Technology is a viable technology that has been reliably used in the defense and aerospace industry for over 20 years. Embedded Passive (Resistors and Capacitors) Technology have a great potential for high frequency and high density applications. It also provides better signal performance, reduced parasitic and cross talk. This paper summarizes the selection of resistor embedded materials, evaluations of resistive material (Phase 1) and duplication of a complex digital design (Phase 2). Phase 1 –resistive materials (Foil 25Ω/sq NiCr and 1kΩ/sq CrSiO) and resistive-Ply materials (25Ω/sq and 250Ω/sq NiP) were chosen for evaluation....
Publisher: Honeywell International
Jan 02, 2014 | Bankeem Chheda and S. Manian Ramkumar, Ph.D.; Rochester Institute of Technology-CEMA, Reza Ghaffarian; Ph.D. Jet Propulsion Laboratory.
With ROHS compliance the transition to lead-free is inevitable. Several lead-free alloys are available in the market and its reliability has been the main concern. The results from this experimental research aims at making a comparison of different lead-free alloy combinations. Thermal shock and drop tests are a part of this experimental study....
Publisher: Jet Propulsion Laboratory
Dec 27, 2013 | Mario Scalzo Senior Technical Support Engineer CSMTPE, Six-Sigma Black Belt
The head-in-pillow defect has become a relatively common failure mode in the industry since the implementation of Pb-free technologies, generating much concern. A head-in-pillow defect is the incomplete wetting of the entire solder joint of a Ball-Grid Array (BGA), Chip-Scale Package (CSP), or even a Package-On-Package (PoP) and is characterized as a process anomaly, where the solder paste and BGA ball both reflow but do not coalesce. When looking at a cross-section, it actually looks like a head has pressed into a soft pillow. There are two main sources of head-in-pillow defects: poor wetting and PWB or package warpage. Poor wetting can result from a variety of sources, such as solder ball oxidation, an inappropriate thermal reflow profile or poor fluxing action. This paper addresses the three sources or contributing issues (supply, process & material) of the head-in-pillow defects. It will thoroughly review these three issues and how they relate to result in head-in pillow defects. In addition, a head-in-pillow elimination plan will be presented with real life examples will be to illustrate these head-in-pillow solutions....
Publisher: Indium Corporation
Dec 19, 2013 | Rick Gunn, Vice President of Engineering / Chief Technology Officer, Nextek Incorporated.
With the adoption of RoHS and implementation of Lead Free solders a major concern is how this will impact reliability. Both commercial and military hardware are impacted by this change even though military hardware is considered exempt from the requirements of RoHS. As the supply chain has moved to the new lead free alloys both markets are being forced to understand these impacts and form risk mitigation strategies to deal with the change. This paper documents the effect of mixing Leaded and Lead Free alloys on BGA devices and how this impacts reliability. Three of the most common pitch BGA packages are included in the study to determine if the risk is the same as pitches decrease...
Dec 11, 2013 | Greg Caswell, Sr. Member of the Technical Staff, DfR Solutions
Today's analyses of electronics reliability at the system level typically use a "black box approach", with relatively poor understanding of the behaviors and performances of such "black boxes" and how they physically and electrically interact (...) The incorporation of more rigorous and more informative approaches and techniques needs to better understand (...) Understanding the Physics of Failure (PoF) is imperative. It is a formalized and structured approach to Failure Analysis/Forensics Engineering that focuses on total learning and not only fixing a particular current problem (...) In this paper we will present an explanation of various physical models that could be deployed through this method, namely, wire bond failures; thermo-mechanical fatigue; and vibration....
Publisher: DfR Solutions
College Park, Maryland, United States
DfR Solutions has world-renowned expertise in applying the science of Reliability Physics to electrical and electronics technologies, and is a leading provider of quality, reliability, and durability (QRD) research and consulting for the electronics industry.
Dec 05, 2013 | Susie Krzmarzick, John Dzarnoski, Yangjun Xing.
The functionality of electronic devices continues to increase at an extraordinary rate. Simultaneously consumers are expecting even more and in ever smaller packages. One enabler for shrinking electronics has been the flexible circuit board that allows the circuit board to fit a wide variety of shapes. Flexible printed circuits (FPC) have the capability to be very thin and can have unpackaged components directly attached using surface mount technology (SMT) and flip chip on flex technologies. Bare die can also be thinned and attached very close to the circuit board. However one caveat of high density flexible circuit boards with thin die is that they can be very fragile. The use of back side films and underfill can protect the die making circuits more robust. For underfill to work well it requires good adhesion to the circuit board which can mean that flux residues under the die normally must be removed prior to underfilling. ...
Publisher: Starkey Hearing Technologies
Nov 27, 2013 | Olivier Vendier, Jean-Louis Cazaux, Jean-Luc Lortal; Thales Alenia Space.
The need in complexity for microwave space products such as active BFNs (Beam Forming Networks) is increasing, with a significantly growing number of amplitude / phase control points (number of beams * numbers of radiating elements). As a consequence, the RF component’s package topology is evolving (larger number of I/Os, interconnections densification ...) which directly affect the routing and architecture of the multilayer boards they are mounted on. It then becomes necessary to improve the density of these boards (...) This paper will present the work performed to achieve LCP-based high density multilayer structures, describing the different electrical and technological breadboards manufactured and tested and presenting the results obtained....
Nov 21, 2013 | Chrys Shea, Shea Engineering Services; Ray Whittier, Vicor Corporation
Previous experimentation on a highly miniaturized and densely populated SMT assembly revealed the optimum stencil alloy and flux-repellent coating for its stencil printing process. Production implementation of the materials that were identified in the study resulted in approximately 5% print yield improvement across all assemblies throughout the operation, validating the results of the initial tests. A new set of studies was launched to focus on the materials themselves, with the purpose of optimizing their performance on the assembly line (...) Results of the prior tests are reviewed, and the new test vehicle, experimental setup and results are presented and discussed....
Publisher: Shea Engineering Services
Nov 14, 2013 | Nordson Asymtek
Understanding accuracy and repeatability is an important step to analyze fluid dispensing system performance. They can also be prone to misinterpretation when reviewing a product specification. A dispensing motion system can be made to perform better or worse under different operating conditions. This article will explain accuracy and repeatability, and how they can be applied to different specifications. It will also discuss key considerations when interpreting accuracy and repeatability for decision making....
Publisher: Nordson ASYMTEK
Carlsbad, California, United States
A leader in automated fluid dispensing, jetting and conformal coating. Products range from benchtop dispensers and stand-alone dispensing workstations to fully automated, in-line conveyorized systems.