Electronics Manufacturing Technical Articles

Fix The Process Not Just The Product

Apr 03, 2015 | Mary Elmallakh, M. Sc. and Paul Groome Digitaltest Inc. Andy Shelton Pulse Communications, Inc.

Understanding your process and how to minimize defects has always been important. Nowadays, its importance is increasing with the complexity of products and the customers demand for higher quality. Quality Management Solutions (QMS) that integrate real-time test and inspection results with engineering and production data, can allow the optimization of the entire manufacturing process. We will describe the cost and time benefits of a QMS system when integrated with engineering data and manufacturing processes. We will use real examples that can be derived from integrating this data. This paper also discusses the aspects of Quality Management Software that enables electronic manufacturers to efficiently deliver products while achieving higher quality, reduce manufacturing costs and cutting repair time. Key words: Quality Management Software, ICT, Repair workstations, First Pass Yield, Pareto analysis, Flying Probe, QMS. ...

Publisher: Digitaltest Inc.

Jetting Strategies for mBGAs a question of give and take...

Apr 02, 2015 | Gustaf Mårtensson; BioNano Systems Laboratory, MC2, Petter Svensson, Thomas Kurian; Micronic Mydata AB

The demands on volume delivery and positioning accuracy for solder paste deposits are increasing as the size and complexity of circuits continue to develop in the electronics industry. According to the iNEMI 2013 placement accuracy for these kinds of components will reach 6 sigma placement accuracy in X and Y of 30 um by 2023.

This study attempts to understand the dependencies on piezo actuation pulse profile on jetting deposit quality, especially focused on positioning, satellites and shape. The correlation of deposit diameter and positioning deviation as a function of piezo actuation profile shows that positioning error for deposits increase almost monotonically with decreasing droplet volume irrespective of the piezo-actuation profile. The trends for shape and satellite levels are not as clear and demand further study. ...

Publisher: Mycronic AB

How to process C4 (FLIPCHIP)

Mar 29, 2015 | Jason Wu

Application Notes – C4 (FLIPCHIP) Category Description of the category The C4 category is used to describe certain area array devices which have solder bumps (bumps) distributed over the surface of the device. The C4 category is also referred to by the name flipchip. In contrast to the BGA devices, C4 devices do not necessarily have the bumps arranged on a regular grid. The C4 algorithm was originally developed for very fine pitch devices. It has since been extended to find (center) larger components....

Publisher: Shenzhen Southern Machinery Sales and Service Co., Ltd

The best way to merger 2 SMT lines in one production line

Mar 28, 2015 | Jason Wu

Saving power consumption more then $30K per year, ROI less 6 months. please contact: jasonwu@smthelp.com or w25605@gmail.com if you are interested....

Publisher: Shenzhen Southern Machinery Sales and Service Co., Ltd

What is Procedure for Measuring the Airflow of the Auto Insertion machine - VCD

Mar 27, 2015 | Jason Wu

This procedure documents the method and apparatus for measuring the average air consumption and the peak air flow for Through Hole -- Axial Insertion Machine....

Publisher: Shenzhen Southern Machinery Sales and Service Co., Ltd

How to design Through Hole PCB

Mar 27, 2015 | Jason Wu

Equipment Throughput Calculation • Simplistic Throughput Calculation – Deduct a basic rule of thumb percentage from the maximum machine cycle rate. – The accuracy of this method is highly questionable. • Effective Throughput Calculation – Machine de-rate calculated using statistical data based on actual run data and component counts. Also considers PPM, Product Changeover, Board – Load/Unload Time, and Downtime....

Publisher: Shenzhen Southern Machinery Sales and Service Co., Ltd

Effectiveness of Conformal Coat to Prevent Corrosion of Nickel-palladium-gold-finished Terminals

Mar 26, 2015 | Michael Osterman

Nickel-palladium-gold-finished terminals are susceptible to creep corrosion. Excessive creep corrosion can result in device failure due to insulation resistance loss between adjacent terminals. The mixed flowing gas test has been demonstrated to produce creep corrosion on parts with nickel-palladium-gold finished terminals. Conformal coats are often used to protect printed wiring assemblies from failure due to moisture and corrosion. However, coating may not be sufficient to protect lead terminations from failure.

In this study, acrylic, silicone, urethane, parylene, and atomic layer deposit (ALD) coatings were examined for their effectiveness at preventing corrosion of nickel-palladium-gold-finished terminals....

Publisher: University of Maryland

Exceptional Optoelectronic Properties of Hydrogenated Bilayer Silicene

Mar 19, 2015 | Bing Huang, Hui-Xiong Deng, Hoonkyung Lee, Mina Yoon, Bobby G. Sumpter, Feng Liu, Sean C. Smith, Su-Huai Wei

Silicon is arguably the best electronic material, but it is not a good optoelectronic material. By employing first-principles calculations and the cluster-expansion approach, we discover that hydrogenated bilayer silicene (BS) shows promising potential as a new kind of optoelectronic material. Most significantly, hydrogenation converts the intrinsic BS, a strongly indirect semiconductor, into a direct-gap semiconductor with a widely tunable band gap. At low hydrogen concentrations, four ground states of single- and double sided hydrogenated BS are characterized by dipole-allowed direct (or quasidirect) band gaps in the desirable range from 1 to 1.5 eV, suitable for solar applications. At high hydrogen concentrations, three well-ordered double-sided hydrogenated BS structures exhibit direct (or quasidirect) band gaps in the color range of red, green, and blue, affording white light-emitting diodes. Our findings open opportunities to search for new silicon-based light-absorption and light-emitting materials for earth-abundant, high efficiency, optoelectronic applications.

Originally published by the American Physical Society...

Publisher: Oak Ridge National Laboratory

Miniaturization with Help of Reduced Component to Component Spacing

Mar 12, 2015 | Jonas Sjoberg, Ranilo Aranda, David Geiger, Anwar Mohammed, Murad Kurwa - Flextronics Advanced Engineering Group

Miniaturization and the integration of a growing number of functions in portable electronic devices require an extremely high packaging density for the active and passive components. There are many ways to increase the packaging density and a few examples would be to stack them with Package on Package (PoP), fine pitch CSP's, 01005 and last but not least reduced component to component spacing for active and passive components (...)

This paper will discuss different layouts, assembly and material selections to reduce component to component spacing down to 100-125um (4-5mil) from today’s mainstream of 150-200um (6-8mil) component to component spacing....

Publisher: Flex (Flextronics International)

Conformal Coating over No Clean Flux Residues

Mar 04, 2015 | K.Seelig, T.O'Neill

As the proliferation of modern day electronics continues to drive miniaturization and functionality, electronic designers/assemblers face the issue of environmental exposure and uncommon applications never previously contemplated. This reality, coupled with the goal of reducing the environmental and health implications of the production and disposal of these devices, has forced manufacturers to reconsider the materials used in production. Furthermore, the need to increase package density and reduce costs has led to the rapid deployment of leadless packages such as QFN, POP, LGA, and Micro-BGA. In many cases, the manufacturers of these devices will recommend the use of no clean fluxes due to concerns over the ability to consistently remove flux residues from under and around these devices. These concerns, along with the need to implement a tin whisker mitigation strategy and/or increase environmental tolerance, have led to the conundrum of applying conformal coating over no clean residues....

Publisher: AIM Solder

Position Accuracy Machines for Selective Soldering Fine Pitch Components

Feb 27, 2015 | Gerjan Diepstraten

The drive towards fine pitch technology also affects the soldering processes. Selective soldering is a reliable soldering process for THT (through hole) connectors and offers a wide process window for designers. THT connectors can be soldered on the top and bottom side of boards, board in board, PCBs to metal shields or housing out of plastic or aluminum are today's state of the art. The materials that are used to make the solder connections require higher temperatures. Due to the introduction of lead-free alloys, the boards need more heat to get the barrels filled with solder. This not only affects the properties of the flux and components, but the operation temperatures of solder machines become higher (...)

First the impact of temperature will be discussed for the separate process steps and for machine tooling. In the experimental part measurements are done to verify the accuracy that can be achieved using today's selective soldering machines. Dedicated tooling is designed to achieve special requirements with respect to component position accuracy....

Publisher: Vitronics Soltec

New Requirements for SIR Measurement

Feb 27, 2015 | Jörg Trodler; Heraeus Materials Technology GmbHo.KG, Mathias Nowottnick, Prof. University of Rostock.

During the last period of newly assembled electrical devices (pcbs), new component types like LGA and QFN were also qualified as well as smaller passive components with reliability requirements based on the automotive and industrial industry. In the narrow gaps under components, residues can accumulate more by the capillary forces. This is not that much a surface resistance than an interface issue. Also that the flux residues under such types of components creates interaction with the solder resists from the pcb, as well as the component body was not completely described in the standard SIR measurement. On the other hand also, electrical influence with higher voltage creates new terms and conditions, in particular the combination of power and logic in such devices. The standard SIR measurement cannot analyze those combinations.

The paper will discuss the requirements for a measurement process, and will give results. The influences of the pcb and component quality will also be discussed. Furthermore it will describe requirements for nc solder paste to increase the chemical/thermical/electrical reliability for whole devices...

Publisher: Heraeus

Numerical Study on New Pin Pull Test for Pad Cratering Of PCB

Feb 19, 2015 | Billy Hu, Jesus Tan

Pad cratering is an important failure mode besides crack of solder joint as it’ll pass the regular test but have impact on the long term reliability of the product. A new pin pull test method with solder ball attached and positioning the test board at an angle of 30º is employed to study the strength of pad cratering. This new method clearly reveals the failure mechanism. And a proper way to interpret the finite element analysis (FEA) result is discussed. Impact of pad dimension, width and angle of copper trace on the strength is included. Some findings not included in previous research could help to guide the design for better performance...

Publisher: Flex (Flextronics International)

Evaluating the Mechanical Reliability of Ball Grid Array (BGA) Flexible Surface-Mount Electronics Packaging under Isothermal Ageing

Feb 12, 2015 | Sabuj Mallik, Ahmed Z El Mehdawi

Electronic systems are known to be affected by the environmental and mechanical conditions, such as humidity, temperature, thermal shocks and vibration. These adverse environmental operating conditions, with time, could degrade the mechanical efficiency of the system and might lead to catastrophic failures.

The aim of this study is to investigate the mechanical integrity of lead-free ball grid array (BGA) solder joints subjected to isothermal ageing at 150°C for up to 1000 hours. Upon ageing at 150°C the Sn-3.5Ag solder alloy initially age-softened for up to 200 hours. This behaviour was linked to the coarsening of grains. When aged beyond 200 hours the shear strength was found to increase up to 400 hours. This age-hardening was correlated with precipitation of hard Ag3Sn particles in Sn matrix. Further ageing resulted in gradual decrease in shear strength. This can be explained as the combined effect of precipitation coarsening and growth of intermetallic layer. The fractured surfaces of the broken solder balls were also investigated under a Scanning Electron Microscope. The shear failures were generally due to ductile fractures in bulk solders irrespective of the ageing time....

Publisher: School of Engineering, University of Greenwich

Rework Stations: Meeting the Challenges of Lead-Free Solders

Feb 12, 2015 | Nigel Charig

Market forces, particularly legislation against the use of lead in electronics, have driven electronics manufacturers towards lead-free solders for PCB assembly and rework. This approach creates challenges because of the relatively high temperatures needed for lead-free soldering. Additionally, lead-free solder alloys typically do not wet or wick as easily as Sn63Pb37 leaded types. As PCBs often include both BGAs and simpler discrete devices, a lead-free rework capability should include a suitable soldering station and a BGA rework station. This article shows how such equipment can be adapted to overcome the lead-free issues and provide a successful reworking facility....

Publisher: Cupio Yestech Europe

Basics of Ball Grid Arrays (BGAs)

Feb 05, 2015 | Advanced Assembly

Ball grid arrays are the boon and bane of engineers and printed circuit board designers the world over. Their unparalleled pin density and low lead inductance are essential in today's high pin count, high frequency integrated circuits. However, that same pin density and unique interface create a challenge unique unto themselves. These challenges need to be faced head on since the ball grid array (BGA) is prevalent in modern PCBs. While there are entire textbooks that cover the topic of BGAs, their use and fanout techniques, the quick overview provided here offers an engineer a good starting point for improving BGA designs....

Publisher: Advanced Assembly, LLC.

An Alternative Solvent with Low Global Warming Potential

Feb 05, 2015 | R. Basu and R. Hulse

In the past 20 yrs the solvent industry has gone through a great deal of change. In the early 1990s, CFC-113 and 1,1,1-trichloroethane were the workhorses of the industry. The Montreal Protocol to phase-out substances that deplete the Earth's protective Ozone Layer was implemented in the mid 1990s. After phase-out of the CFC solvents, the solvent industry fragmented to a variety of cleaning solutions.

The electronics industry was a large user of CFC solvents and many of these applications changed to aqueous based cleaners (...) But those alternatives are now facing various problems: e.g. aqueous based cleaners use a lot of energy, require long drying times, use equipment that requires frequent maintenance, and require a large footprint; no-clean fluxes leave flux residues; and trichloroethylene and n-propyl bromide have toxicity issues. In response to these serious issues newer solvents and blends are being introduced in the marketplace...

Publisher: Honeywell International

BVA: Molded Cu Wire Contact Solution for Very High Density Package-on- Package (PoP) Applications

Jan 28, 2015 | Vern Solberg, Ilyas Mohammed

Stacking heterogeneous semiconductor die (memory and logic) within the same package outline can be considered for less complex applications but combining the memory and processor functions in a single package has compromised test efficiency and overall package assembly yield. Separation and packaging the semiconductor functions into sections, on the other hand, has proved to be more efficient and, even though two interposers are required, more economical. The separated logic and memory sections are configured with the same uniform outline for vertical stacking (package-on-package). The most common configuration places the logic section as the base with second tier memory section soldered to a mating contact pattern.

This paper addresses the primary technological challenges for reducing contact pitch and package-on-package interface technology....

Publisher: Invensas Corporation

Radar Control Terminal (RCT) units

Jan 26, 2015 | Ensil

In 2005 Raytheon Technical Services Company, now Raytheon Information, Intelligence and Services (Raytheon IIS), approached Ensil regarding the repair of their manufactured Radar Control Terminal (RCT) units. The RCT TRS P/N 13563090-2, a key component in the AN/MPQ-64 Sentinel System, consisted of outdated parts which caused minor to major unit failures. Ensil repaired the RCT's at every turn, correcting any component with the parts still in circulation (mother boards, displays, power supplies) to provide the client with the best available technology. These repairs were completed to military standards and kept the RCT effective, allowing for the Sentinel radar to remain operational. However, the supply of outdated parts was eventually no longer available. Ensil offered the best possible solution, utilizing the skills of their knowledgeable engineering staff, they would reverse engineer a new computer to replace the obsolete RCT while maintaining the same form, fit and function....

Publisher: Ensil

High Temperature Ceramic Capacitors for Deep Well Applications

Jan 22, 2015 | R. Phillips, J. Bultitude, A. Gurav, K. Park, S. Murillo, P. Flores, M. Laps.

Temperature requirements for ceramic capacitors have increased significantly with recent advances in deep-well drilling technology. Increasing demand for oil and natural gas has driven the technology to deeper and deeper deposits resulting in extreme temperature environments up to 200°C and above. A novel capacitor solution utilizing temperature-stable base-metal electrode capacitors in a molded and leaded package addresses the growing market high temperature demands of (1) capacitance stability, (2) long service life, and (3) mechanical durability. A range of high temperature C0G capacitors capable of meeting this 200°C and above high temperature environment has been developed.

This paper will review the electrical, reliability, and mechanical performance of this new capacitor solution...

Publisher: KEMET Electronics Corporation

Automotive Safety Systems Driving Growth in Automotive Sensor Cable Assemblies

Jan 12, 2015 | Pete Doyon, VP, Product Management, Schleuniger Inc.

V2V is a collision avoidance technology that transmits data between vehicles to help warn drivers of potential crashes. This technology would improve safety by allowing vehicles to communicate with each other and exchange basic safety data, such as position and speed and warn the driver of potentially dangerous situations....

Publisher: Schleuniger, Inc.

The Effect of Pb Mixing Levels on Solder Joint Reliability and Failure Mode of Backward Compatible, High Density Ball Grid Array Assemblies

Jan 08, 2015 | Richard Coyle, Richard Popowich, Debra Fleming, Peter Read - Alcatel Lucent, Raiyo Aspandiar, Vasu Vasudevan, Steve Tisdale - Intel Corporation, Iulia Muntele - Sanmina Corporation.

Regardless of the accelerating trend for design and conversion to Pb-free manufacturing, many high reliability electronic equipment producers continue to manufacture and support tin-lead (SnPb) electronic products. Certain high reliability electronic products from the telecommunication, military, and medical sectors manufacture using SnPb solder assembly and remain in compliance with the RoHS Directive (restriction on certain hazardous substances) by invoking the European Union Pb-in-solder exemption.

Sustaining SnPb manufacturing has become more challenging because the global component supply chain is converting rapidly to Pb-free offerings and has a decreasing motivation to continue producing SnPb product for the low-volume, high reliability end users. Availability of critical, larger SnPb BGA components is a growing concern...

Publisher: Sanmina-SCI

The Last Will And Testament of the BGA Void

Jan 05, 2015 | Dave Hillman, Dave Adams, Tim Pearson, Brad Williams, Brittany Petrick, Ross Wilcoxon - Rockwell Collins, Dr. David Bernard, John Travis, Dr. Evstatin Krastev, Vineeth Bastin - Nordson Dage.

The impact of voiding on the solder joint integrity of ball grid arrays (BGAs)/chip scale packages (CSPs) can be a topic of lengthy and energetic discussion. Detailed industry investigations have shown that voids have little effect on solder joint integrity unless they fall into specific location/geometry configurations. These investigations have focused on thermal cycle testing at 0°C-100°C, which is typically used to evaluate commercial electronic products.

This paper documents an investigation to determine the impact of voids in BGA and CSP components using thermal cycle testing (-55°C to +125°C) in accordance with the IPC-9701 specification for tin/lead solder alloys. This temperature range is more typical of military and other high performance product use environments. A proposed BGA void requirement revision for the IPC-JSTD-001 specification will be extracted from the results analysis....

Publisher: Rockwell Collins

Profiled Squeegee Blade: Rewrites the Rules for Angle of Attack

Dec 24, 2014 | Ricky Bennett, Rich Lieske - Lu-Con Technologies, Corey Beech - RiverBend Electronics

For centuries, the squeegee blade has been used throughout many applications for depositing viscous materials through screens and stencils to transfer images on to substrates, from cloth material to electronic circuit boards. One area of blade printing mechanics that have been reviewed many times is the angle of attack of the blade. Typically it has been tested from 45 degrees to 60 degrees to optimize the printing quality and efficiency. However, this typically ends up as a compromise, from fill characteristics (45 degrees) to print definition (60 degrees). This paper will present the revolutionary performance of the profiled squeegee blade, which has recently been developed to create a virtual multi angle of attack for unsurpassed process control for all types of stencil printing processes....

Publisher: Lu-Con Technologies

Head in Pillow X-ray Inspection at Flextronics

Dec 18, 2014 | Alejandro Castellanos, Adalberto Gutierrez, Gilberto Martin, Matthew Vandiver, Ranga Dematampitiya, Hung Le, Elliott Le, Phuong Chau, Hao Cui, An Qi Zhao, Wei Bing Qian, Fuqing Li, Jacky Yao, Jiyang Zhang, Leonard Brisan, Cristian Gurka, Shane Young

Manufacturing technology faces challenges with new packages/process when confronting the need for high yields. Identifying product defects associated with the manufacturing process is a critical part of electronics manufacturing. In this project, we focus on how to use AXI to identify BGA Head-in-Pillow (HIP), which is challenging for AXI testing. Our goal is to help us understand the capabilities of current AXI machines....

Publisher: Flex (Flextronics International)

Failure Modes in Wire bonded and Flip Chip Packages

Dec 11, 2014 | Mumtaz Y. Bora

The growth of portable and wireless products is driving the miniaturization of packages resulting in the development of many types of thin form factor packages and cost effective assembly processes. Wire bonded packages using conventional copper lead frame have been used in industry for quite some time. However, the demand for consumer electronics is driving the need for flip chip interconnects as these packages shorten the signals, reduce inductance and improve functionality as compared to the wire bonded packages. The flip chip packages have solder bumps as interconnects instead of wire bonds and typically use an interposer or organic substrate instead of a metal lead frame (...)

The paper provides a general overview of typical defects and failure modes seen in package assembly and reviews the efforts needed to understand new failure modes during package assembly. The root cause evaluations and lessons learned as the factory transitioned to thin form factor packages are shared...

Publisher: Peregrine Semiconductor

Metal-based Inkjet Inks for Printed Electronics

Dec 04, 2014 | Alexander Kamyshny, Joachim Steinke, Shlomo Magdassi

A review on applications of metal-based inkjet inks for printed electronics with a particular focus on inks containing metal nanoparticles, complexes and metallo-organic compounds. The review describes the preparation of such inks and obtaining conductive patterns by using various sintering methods: thermal, photonic, microwave, plasma, electrical, and chemically triggered. Various applications of metal-based inkjet inks (metallization of solar cell, RFID antennas, OLEDs, thin film transistors, electroluminescence devices) are reviewed....

Publisher: Hebrew University of Jerusalem

Preparation, Manufacturing Lead-Free Soldering Alloy

Nov 28, 2014 | Tarik Talib Issa, Asmaa Shawky Khalil

A soldering alloy composition Sn40-Bi60 has been manufactured by quenching method to achieve the both cast and wire shape. Differential scanning calorimetric (DSC) was done to study the melting behavior for a large portion of the alloy melts sharply at a approximately 136 C0 ,the melting point of Sn-Bi. X-Ray diffraction and optical microscopy were used to analyzed its microstructure characterization. The hardness of the alloys has been tested and find at a value 2 HRB as ductile form....

Publisher: University of Baghdad

Effects of Packaging Materials on the Lifetime of LED Modules Under High Temperature Test

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

Advanced Thermal Management Solutions on PCBs for High Power Applications

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

Effect of Process Variations on Solder Joint Reliability for Nickel-based Surface Finishes

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....

Publisher: Atotech

Solder Joint Reliability Under Realistic Service Conditions

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 Corporation

5 Questions to Ask Before Choosing a New Cut and Strip Machine

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.

Combination of Spray and Soak Improves Cleaning under Bottom Terminations

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

Oxide Thickness and Solderability Methodology to Determine Long Term Storage of BGAs and QFPs

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:

• Fab and assembly factory transfers
• Product obsolescence requiring customers make lifetime/EOL purchases
• Providing extended service (10+ years) on vehicles
• Other program needs

* Integrity of EOL products in terms of solderability needs to be verified....

Publisher: Freescale Semiconductor Inc

Cleaning Of Assembled PCBs - A Crucial Way of Enhancing Product Reliability and Avoiding Problems in the Field

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 USA LLC

Assembly Process Feasibility of Low/No Silver Alloy Solder Paste Materials

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: Flex (Flextronics International)

Taking the LED Pick and Place Challenge

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.

Predicting the Lifetime of the PCB - From Experiment to Simulation

Sep 18, 2014 | Markus Leitgeb, AT&S Peter Fuchs, PCCL.

Two major drivers in electronic industry are electrical and mechanical miniaturization. Both induce major changes in the material selection as well as in the design. Nevertheless, the mechanical and thermal reliability of a Printed Circuit Board (PCB) has to remain at the same high level or even increase (e.g. multiple lead-free soldering). To achieve these reliability targets, extensive testing has to be done with bare PCB as well as assembled PCB. These tests are time consuming and cost intensive. The PCBs have to be produced, assembled, tested and finally a detailed failure analysis is required to be performed.

This paper examines the development of our concept and has the potential to enable the prediction of the lifetime of the PCB using accelerated testing methods and finite element simulations....

Publisher: AT&S

Plastic vs Metal Stencils for Prototype Printing

Sep 11, 2014 | Bob Wettermann.

This article goes through the pluses and minuses of using plastic stencils for DIY prototypes. The release efficiency is measured and "rules of thumb" for using one type vs another is explained....

Publisher: BEST Inc.

Reliability of Reworked QFNs

Sep 11, 2014 | CRANE.

In this DOD study the reliability of reworked QFNs is studied with the outcome being that a stay in place stencil does not impact the reliability of a QFN reworked using this technique...

Publisher: BEST Inc.

Reballing a QFN Simplifies QFN Rework

Sep 11, 2014 | Bob Wettermann.

There are a variety of methods one can use to rework QFNs. This paper explains one of the ways to get very little center ground voiding while making it easy to place a tiny component with almost no keep out areas....

Publisher: BEST Inc.

Counterfeit Integrated Circuits: Detection, Avoidance, and the Challenges Ahead.

Sep 04, 2014 | U. Guin, M. Tehranipoor - ECE Department, University of Connecticut, D. DiMase - Honeywell Inc.,

The counterfeiting of electronic components has become a major challenge in the 21st century. The electronic component supply chain has been greatly affected by widespread counterfeit incidents. A specialized service of testing, detection, and avoidance must be created to tackle the worldwide outbreak of counterfeit integrated circuits (ICs). So far, there are standards and programs in place for outlining the testing, documenting, and reporting procedures. However, there is not yet enough research addressing the detection and avoidance of such counterfeit parts.

In this paper we will present, in detail, all types of counterfeits, the defects present in them, and their detection methods. We will then describe the challenges to implementing these test methods and to their effectiveness. We will present several anti-counterfeit measures to prevent this widespread counterfeiting, and we also consider the effectiveness and limitations of these anti-counterfeiting techniques....

Publisher: Honeywell International

The Effect of Coating and Potting on the Reliability of QFN Devices.

Aug 28, 2014 | Greg Caswell, Cheryl Tulkoff.

The fastest growing package types in the electronics industry today are Bottom Termination Components (BTCs). While the advantages of BTCs are well documented, they pose significant reliability challenges to users. One of the most common drivers for reliability failures is the inappropriate adoption of new technologies. This is especially true for new component packaging like BTCs. Obtaining relevant information can be difficult since information is often segmented and the focus is on design opportunities not on reliability risks (...)

Commonly used conformal coating and potting processes have resulted in shortened fatigue life under thermal cycling conditions. Why do conformal coating and potting reduce fatigue life? This paper details work undertaken to understand the mechanisms underlying this reduction. Verification and determination of mechanical properties of some common materials are performed and highlighted. Recommendations for material selection and housing design are also given....

Publisher: DfR Solutions (acquired by ANSYS Inc)

Implementing Warpage Management: A Five-Step Process for EMS Providers

Aug 19, 2014 | Ken Chiavone

Warpage management consists of planning, measuring, analyzing, sharing, and reacting to data related to the surface shapes of electronics components as they change throughout the reflow assembly process. Leading semiconductor manufacturers have had warpage management systems in place for ten years or more, mainly because microchip package warpage must be understood and compensated for in order to attain high assembly yields. Similarly, newer device architectures such as package-on-package and system-on-a-chip are sensitive to warpage-related assembly issues, and companies involved in the manufacture and assembly of these devices tend to have the most advanced warpage management programs....

Publisher: Akrometrix

Advanced Second Level Assembly Analysis Techniques - Troubleshooting Head-In-Pillow, Opens, and Shorts with Dual Full-Field 3D Surface Warpage Data Sets/

Aug 19, 2014 | Ken Chiavone

SMT assembly planning and failure analysis of surface mount assembly defects often include component warpage evaluation. Coplanarity values of Integrated Circuit packages have traditionally been used to establish pass/fail limits. As surface mount components become smaller, with denser interconnect arrays, and processes such package-on-package assembly become prevalent, advanced methods using dual surface full-field data become critical for effective Assembly Planning, Quality Assurance, and Failure Analysis. A more complete approach than just measuring the coplanarity of the package is needed. Analyzing the gap between two surfaces that are constantly changing during the reflow thermal cycle is required, to effectively address the challenges of modern SMT assembly....

Publisher: Akrometrix

Ready to Start Measuring PCB Warpage during Reflow? Why and How to Use the New IPC-9641 Standard

Aug 19, 2014 | Ken Chiavone

Understanding warpage of package attach locations on PCBs under reflow temperature conditions is critical in surface mount technology. A new industry standard, IPC 9641, addresses this topic directly for the first time as an international standard.

This paper begins by summarizing the sections of the IPC 9641 standard, including, measurement equipment selection, test setup and methodology, and accuracy verification. The paper goes further to discuss practical implementation of the IPC 9641 standards. Key advantages and disadvantages between available warpage measurement methods are highlighted. Choosing the correct measurement technique depends on requirements for warpage resolution, data density, measurement volume, and data correlation. From industry experience, best practice recommendations are made on warpage management of PCB land areas, covering how to setup, run, analyze, and report on local area PCB warpage.

The release of IPC 9641 shows that flatness over temperature of the package land area on the PCB is critical to the SMT industry. Furthermore, compatibility of shapes between attaching surfaces in SMT, like a package and PCB, will be critical to product yield and quality in years to come....

Publisher: Akrometrix

Advanced Organic Substrate Technologies To Enable Extreme Electronics Miniaturization.

Aug 14, 2014 | Susan Bagen, Dave Alcoe, Kim Blackwell, Frank Egitto.

High reliability applications for high performance computing, military, medical and industrial applications are driving electronics packaging advancements toward increased functionality with decreasing degrees of size, weight and power (SWaP) The substrate technology selected for the electronics package is a key enabling technology towards achieving SWaP. Standard printed circuit boards (PWBs) utilize dielectric materials containing glass cloth, which can limit circuit density and performance, as well as inhibit the ability to achieve reliable assemblies with bare semiconductor die components. Ceramic substrates often used in lieu of PWBs for chip packaging have disadvantages of weight, marginal electrical performance and reliability as compared to organic technologies. Alternative materials including thin, particle-containing organic substrates, liquid crystal polymer (LCP) and microflex enable SWaP, while overcoming the limitations of PWBs and ceramic.

This paper will discuss the use of these alternative organic substrate materials to achieve extreme electronics miniaturization with outstanding electrical performance and high reliability. The effect of substrate type on chip-package interaction and resulting reliability will be discussed. Microflex assemblies to achieve extreme miniaturization and atypical form factors driven by implantable and in vivo medical applications are also shown....

Publisher: i3 Electronics

Gold Embrittlement In Lead-Free Solder.

Aug 07, 2014 | Craig Hillman, Nathan Blattau, Joelle Arnold, Thomas Johnston, Stephanie Gulbrandsen; DfR Solutions, Julie Silk, Alex Chiu; Agilent Technologies.

Gold embrittlement in SnPb solder is a well-known failure mechanism in electronic assembly. To avoid this issue, prior studies have indicated a maximum gold content of three weight percent. This study attempts to provide similar guidance for Pb-free (SAC305) solder. Standard surface mount devices were assembled with SnPb and SAC305 solder onto printed boards with various thicknesses of gold plating. The gold plating included electroless nickel immersion gold (ENIG) and electrolytic gold of 15, 25, 35, and 50 microinches over nickel. These gold thicknesses resulted in weight percentages between 0.4 to 7.0 weight percent....

Publisher: DfR Solutions (acquired by ANSYS Inc)

Electrostatic Theory of Metal Whiskers.

Jul 31, 2014 | V. G. Karpov, Department of Physics and Astronomy, University of Toledo.

Metal whiskers often grow across leads of electric equipment and electronic package causing current leakage or short circuits and raising significant reliability issues. The nature of metal whiskers remains a mystery after several decades of research. Here, the existence of metal whiskers is attributed to the energy gain due to electrostatic polarization of metal filaments in the electric field. The field is induced by surface imperfections: contaminations, oxide states, grain boundaries, etc. A proposed theory provides closed form expressions and quantitative estimates for the whisker nucleation and growth rates, explains the range of whisker parameters and effects of external biasing, and predicts statistical distribution of their lengths....

Publisher: University of Toledo