Electronics Manufacturing Technical Articles

Pad Cratering Susceptibility Testing with Acoustic Emission

Aug 13, 2015 | Wong Boon San, Julie Silk; Agilent Technologies | Richard Nordstrom, Ph.D.; Acoustic Technology Group,

Pad cratering has become more prevalent with the switch to lead free solders and lead free compatible laminates. This mainly is due to the use of higher reflow temperature, stiffer Pb-free solder alloys, and the more brittle Pb-free compatible laminates. However, pad cratering is difficult to detect by monitoring electric resistance since pad cratering initiates before an electrical failure occurs.

Several methods have been developed to evaluate laminate materials' resistance to pad cratering. Pad-solder level tests include ball shear, ball pull and pin pull. The detailed methods for ball shear, ball pull, and pin pull testing are documented in an industry standard IPC-9708. Bansal, et al. proposed to use acoustic emission (AE) sensors to detect pad cratering during four-point bend test. Currently there is an industry-working group working on test guidelines for acoustic emission measurement during mechanical testing....

Publisher: Agilent Technologies, Inc.

Enclosed Media Printing as an Alternative to Metal Blades

Aug 06, 2015 | Michael L. Martel

Fine pitch/fine feature solder paste printing in PCB assembly has become increasingly difficult as board geometries have become ever more compact. The printing process itself, traditionally the source of 70% of all assembly defects, finds its process window narrowing. The technology of metal blade squeegees, with the aid of new materials, understanding, and settings such as blade angle, has kept pace with all but the smallest applications, e.g., 200μ - .50 AR and 150μ - .375 AR, which have been pushing blade printing technology to its limits.

Enclosed media print head technology has existed, and has been under increasing development, as an alternative to metal squeegee blade printing. Until recently, the performance of enclosed print heads had been comparable to the very best metal squeegees, but advances in enclosed print media technology have now made it a superior alternative to squeegee blades in virtually all applications....

Publisher: Speedline Technologies, Inc.

5 Axis Fluid Dispensing

Jul 31, 2015 | Brian Stumm

Technology is in constant change and circuit assembly is no different. It is becoming more and more advanced as needs change and demands for more capabilities increase. In order to meet these demands, equipment manufacturers are integrating the latest innovations and tools to serve the industry. The need to better protect printed circuit assemblies from harsh environments using automated selective conformal coating is becoming a must. 5 axis fluid dispensing allows conformal coating to be applied to printed circuit assemblies like never before....

Publisher: ETS - Energy Technology Systems, Inc.

Thermal Curing of Conformal Coatings

Jul 27, 2015 | Wes Noble

When it comes to the application of conformal coating, curing the coating plays a key role in the circuit assembly and selective conformal coating process. Curing conformal coating occurs after the coating spray/dispense process is complete. The coating is considered “cured” when the conformal coating on the circuit assembly is sufficiently tack-free to be handled. Curing can sometimes be accomplished at room temperature but takes a considerable amount of time to dry. Accelerated conformal coating curing decreases this drying period, the cure process reaches either the tack-free or a fully dried state but not quite having fully cured properties. Accelerated curing techniques include one or a combination of heat, moisture, UV light, and chemical reaction curing. This article focuses primarily on thermal or heat curing....

Publisher: ETS - Energy Technology Systems, Inc.

Measuring Conformal Coating Thickness

Jul 21, 2015 | Roger Plough

Achieving an even coat at the right desired thickness is a major challenge when it comes to applying conformal coating to a Printed Circuit Board (PCB). Applying a coating too thin will ultimately render the electronic assembly vulnerable to potential environmental risks therefore defeating the purpose of the coating. Apply the coat too thick, and it could leave the electronic specific components non-functional therefore destroying the electronic assembly entirely. Coating thickness must meet quality specifications. Measurements for coating thickness may be taken while film is dry or wet. Once measurements are recorded, thickness is compared to quality specifications and fluid dispensing automation machinery is calibrated as necessary. There are a handful of methods for measuring conformal coating thickness that are commonly used in the Electronic Manufacturing Services (EMS) and Original Electronic Manufacturer (OEM) industries. A few commonly used methods for checking conformal coating thickness include:...

Publisher: ETS - Energy Technology Systems, Inc.

Testing Printed Circuit Boards for Creep Corrosion in Flowers of Sulfur Chamber

Jul 16, 2015 | Haley Fu; iNEMI, Prabjit Singh, Levi Campbell, Jing Zhang; IBM Corporation, Wallace Ables; Dell Corporation, Dem Lee, Jeffrey Lee; iST-Integrated Service Technology, Jane Li, Solomon Zhang; Lenovo Limited Corporation, Simon Lee; The Dow Chemical Company.

Qualification of electronic hardware from a corrosion resistance standpoint has traditionally relied on stressing the hardware in a variety of environments. Before the development of tests based on mixed flowing gas (MFG), hardware was typically exposed to temperature-humidity cycling. In the pre-1980s era, component feature sizes were relatively large. Corrosion, while it did occur, did not in general degrade reliability. There were rare instances of the data center environments releasing corrosive gases and corroding hardware. One that got a lot of publicity was the corrosion by sulfur-bearing gases given off by data center carpeting. More often, corrosion was due to corrosive flux residues left on as-manufactured printed circuit boards (PCBs) that led to ion migration induced electrical shorting. Ion migration induced failures also occurred inside the PCBs due to poor laminate quality and moisture trapped in the laminate layers....

Publisher: iNEMI (International Electronics Manufacturing Initiative)

What is Kelvin Test?

Jul 14, 2015 | Rick Meraw, Todd Kolmodin, Manfred Ludwig, Holger Kern.

The PCB industry is ever changing and adapting to new technologies. OEM specifications and requirements have also advanced due to these technologies. In some cases the OEMs are asking for a low resistance test to be performed on some or all electrical test nets of the PCB or on the holes of the PCB. This requirement is typically not well defined on the fabrication drawing and that leads to misleading conclusions by the fabrication house (...)

This paper will use the data gathered by the company’s operations to outline what a 4-wire Kelvin test is and how it can be used. Several examples will be illustrated of what the 4 wire Kelvin test can and cannot do. A clear definition of what limitations are present during the testing operation will be defined. The paper will assist designers in understanding how the low resistance test can assist them and also identify causes that can identify unwanted concerns/issues....

Publisher: Gardien Services USA

Reliability Study of Bottom Terminated Components

Jul 14, 2015 | Jennifer Nguyen, Hector Marin, David Geiger, Anwar Mohammed, and Murad Kurwa

Bottom terminated components (BTC) are leadless components where terminations are protectively plated on the underside of the package. They are all slightly different and have different names, such as QFN (quad flat no lead), DFN (dual flat no lead), LGA (land grid array) and MLF (micro lead-frame. BTC assembly has increased rapidly in recent years. This type of package is attractive due to its low cost and good performance like improved signal speeds and enhanced thermal performance.

However, bottom terminated components do not have any leads to absorb the stress and strain on the solder joints. It relies on the correct amount of solder deposited during the assembly process for having a good solder joint quality and reliable reliability. Voiding is typically seen on the BTC solder joint, especially on the thermal pad of the component. Voiding creates a major concern on BTC component’s solder joint reliability. There is no current industry standard on the voiding criteria for bottom terminated component. The impact of voiding on solder joint reliability and the impact of voiding on the heat transfer characteristics at BTC component are not well understood. This paper will present some data to address these concerns....

Publisher: Flex (Flextronics International)

Predicting Fatigue of Solder Joints Subjected to High Number of Power Cycles

Jul 09, 2015 | Craig Hillman, Nathan Blattau, Matt Lacy

Solder joint reliability of SMT components connected to printed circuit boards is well documented. However, much of the testing and data is related to high-strain energy thermal cycling experiments relevant to product qualification testing (i.e., -55C to 125C). Relatively little information is available on low-strain, high-cycle fatigue behavior of solder joints, even though this is increasingly common in a number of applications due to energy savings sleep mode, high variation in bandwidth usage and computational requirements, and normal operational profiles in a number of power supply applications.

In this paper, 2512 chip resistors were subjected to a high (>50,000) number of short duration (<10 min) power cycles. Environmental conditions and relevant material properties were documented and the information was inputted into a number of published solder joint fatigue models. The requirements of each model, its approach (crack growth or damage accumulation) and its relevance to high cycle fatigue are discussed....

Publisher: DfR Solutions

Reliability Screening of Lower Melting Point Pb-Free Alloys Containing Bi

Jul 01, 2015 | Joseph M. Juarez, Michael Robinson, Joel Heebink; Honeywell, Polina Snugovsky, Eva Kosiba, Jeffrey Kennedy, Zohreh Bagheri, Subramaniam Suthakaran, Marianne Romansky; Celestica.

Aerospace and military companies continue to exercise RoHS exemptions and to intensively research the long term attachment reliability of RoHS compliant solders. Their products require higher vibration, drop/shock performance, and combined-environment reliability than the conventional SAC305 alloy provides. The NASA-DoD Lead-Free Electronics Project confirmed that pad cratering is one of the dominant failure modes that occur in various board level reliability tests, especially under dynamic loading.

One possible route to improvement of the mechanical and thermo-mechanical properties of solder joints is the use of Pb-free solders with lower process temperatures. Lower temperatures help reduce the possibility of damaging the boards and components, and also may allow for the use of lower Tg board materials which are less prone to pad cratering defects. There are several Sn-Ag-Bi and Sn-Ag-Cu-Bi alloys which melt about 10°C lower than SAC305. The bismuth in these solder compositions not only reduces the melting temperature, but also improves thermo-mechanical behavior. An additional benefit of using Bi-containing solder alloys is the possibility to reduce the propensity to whisker growth...

Publisher: Honeywell International

Return on Investment of a Pre-Reflow AOI System

Jun 30, 2015 | CyberOptics Corporation

This paper describes the losses from defects at the placement process in the SMT line. Two case studies of European and Taiwanese SMT manufacturers illustrate the actual losses from their defects. An evaluation method to select a pre-reflow AOI system maximizing the return on investment (ROI) is introduced. In the end, ROIs of three commercial pre-reflow AOI systems are compared to demonstrate the importance of selecting an appropriate AOI system. This paper will increase the probability that anyone installing an AOI system during the pre-reflow process will obtain a successful gain with short payback period....

Publisher: CyberOptics Corporation

Automated Fluid Dispensing for Epoxy

Jun 30, 2015 | Eric Sari

Robotics for automated fluid dispensing have the ability to apply a variety of materials including epoxy, silicone, and acrylic coatings. These materials are extensively used in today’s high-speed fluid dispensers for the electronics industry.

Whether a dispenser is applying epoxy or another material, the central concept for applying any form of material remains the same. Specific points of an item being dispensed onto are programmed into the dispensing system. The automated fluid dispensers software interprets the programmed information and keeps the travel path in memory. A robotic arm moves fluid dispensing nozzles along this travel path and applies epoxy onto the surface of the item with precise accuracy. Machine speed can be adjusted to emit varying amounts of epoxy. The overall application process is auto-regulating and will not be disrupted....

Publisher: ETS - Energy Technology Systems, Inc.

Reduce labor by automating your Selective Conformal Coating process

Jun 22, 2015 | Brian Stumm, Wes Noble

Applying conformal coatings to electronics has come a long way since the days of manually coating circuit boards. The extreme accuracy and highly repetitive process of automated conformal coatings is moving the electronics industry towards a more defect-free era for conformal coating. It enables new forms of electronics to become better protected, making it possible for electronics to withstand harsher environments than ever before. The following article is meant to aid in clarifying the advantages of specialty coating systems over manual applications for selective conformal coating. ...

Publisher: ETS - Energy Technology Systems, Inc.

PCB Surface Finishes: A General Review

Jun 22, 2015 | Jun Nable, Ph.D., MacDermid Inc. Waterbury, CT

Surface finishing is an integral part of any PCB fabrication. It is generally applied to exposed Cu connectors and conductors on the board. Surface finishing has numerous important functions. It serves as a protective layer for the Cu connectors during storage. The surface finish helps minimize or reduce tarnish of the Cu substrate. Additionally, since it is the layer that comes into contact with other components during assembly, it ensures good solderability between the PCB and the component during assembly. Furthermore after assembly, the finish helps prolong the integrity of the solder joint during use.

A general review of common PCB surface finishes is presented. The advantages and disadvantages of each are discussed and compared. ...

Publisher: MacDermid Inc.

The Use of an Available Color Sensor for Burn-In of LED Products

Jun 18, 2015 | Tom Melly Ph.D.

In the recent past, the Light Emitting Diode (LED) was hailed as the new energy efficient light source that would never have to be replaced. There were claims of 50,000+ hrs lifetime for the humble LED. That story has changed over the last few years as the number and diversity of the LED based products has increased. This is not to say that the original evidence was incorrect, but the initial enthusiastic estimates from the labs did not match the ultimate test, customers. As a result of poor quality products affecting the overall opinion of LED based products, it is critical that manufacturers can be confident in the quality of their product. In current times we want to have products certified, checked and ensure that we have the best quality.

For the purposes of this paper we will look at one aspect of LED product, and this is the Lumen maintenance and estimated lifetime. The method described here does not seek to replace using high quality rating labs, but hopefully will allow the manufacturer to know with confidence that their prototype product, upon going to certification labs will be of a high enough quality that no expensive re-designs are required....

Publisher: Feasa Enterprises Limited

Solder Paste Stencil Design for Optimal QFN Yield and Reliability

Jun 11, 2015 | B. Gumpert

The use of bottom terminated components (BTC) has become widespread, specifically the use of Quad Flat No-lead (QFN) packages. The small outline and low height of this package type, improved electrical and thermal performance relative to older packaging technology, and low cost make the QFN/BTC attractive for many applications.

Over the past 15 years, the implementation of the QFN/BTC package has garnered a great amount of attention due to the assembly and inspection process challenges associated with the package. The difference in solder application parameters between the center pad and the perimeter pads complicates stencil design, and must be given special attention to balance the dissimilar requirements...

Publisher: Lockheed Martin Corporation

Tin Whisker Risk Mitigation for High-Reliability Systems Integrators and Designers

Jun 04, 2015 | David Pinsky, Elizabeth Lambert

Integrators and designers of high-reliability systems exert little or no control over component-level plating processes that affect the propensity for tin whiskering. Challenges of how to assure long-term reliability, while continuing to use COTS parts plated with pure tin, continue to arise.

An integrated, quantitative, standardized methodology is proposed whereby mitigation levels can be selected that are appropriate for specific applications of pure tin for given end-uses. A system of hardware end-use classification is proposed, together with recommended appropriate risk mitigation approaches. An updated version of the application-specific risk assessment algorithm is presented together with recommended thresholds for acceptability within the context of the hardware classifications....

Publisher: Raytheon

Beyond 0402M Placement: Process Considerations for 03015M Microchip Mounting

May 28, 2015 | Brent Fischthal, Sr. Marketing Manager, Products & Solutions Michael Cieslinski, Engineering Manager Panasonic Factory Solutions Company of America.

The printed circuit board assembly industry has long embraced the "Smaller, Lighter, Faster" mantra for electronic devices, especially in our ubiquitous mobile devices. As manufacturers increase smart phone functionality and capability, designers must adopt smaller components to facilitate high-density packaging. Measuring over 40% smaller than today's 0402M (0.4mmx0.2mm) microchip, the new 03015M (0.3mm×0.15mm) microchip epitomizes the bleeding-edge of surface mount component miniaturization.

This presentation will explore board and component trends, and then delve into three critical areas for successful 03015M adoption: placement equipment, assembly materials, and process controls. Beyond machine requirements, the importance of taping specifications, component shape, solder fillet, spacing gap, and stencil design are explored. We will also examine how Adaptive Process Control can increase production yields and reduce defects by placing components to solder position rather than pad. Understanding the process considerations for 03015M component mounting today will help designers and manufacturers transition to successful placement tomorrow....

Publisher: Panasonic Factory Solutions Company of America (PFSA)

“A New Paradigm in Crimping Press Design” By Rob Boyd, Senior Product Manager, Schleuniger, Inc.

May 27, 2015 | Rob Boyd, Senior Product Manager, Schleuniger. Inc.

It goes without saying that manufacturing companies want the highest possible quality at the lowest possible cost. These days, everyone is trying to do more with less in order to stay relevant in a competitive environment....

Publisher: Schleuniger, Inc.

Reliability of Embedded Planar Capacitors under Temperature and Voltage Stress

May 21, 2015 | Mohammed A. Alam, Michael H. Azarian, Michael Osterman and Michael Pecht

In this work the reliability of an embedded planar capacitor laminate under temperature and voltage stress is investigated. The capacitor laminate consisted of an epoxy-BaTiO3 composite sandwiched between two layers of copper. The test vehicle with the embedded capacitors was subjected to a temperature of 125oC and a voltage bias of 200 V for 1000 hours. Capacitance, dissipation factor, and insulation resistance were monitored in-situ. Failed capacitors exhibited a sharp drop in insulation resistance, indicating avalanche breakdown. The decrease in the capacitance after 1000 hours was no more than 8% for any of the devices monitored. The decrease in the capacitance was attributed to delamination in the embedded capacitor laminate and an increase in the spacing between the copper layers....

Publisher: CALCE Center for Advanced Life Cycle Engineering

Reliability of Stacked Microvia

May 14, 2015 | Hardeep Heer, Ryan Wong

The Printed Circuit Board industry has seen a steady reduction in pitch from 1.0mm to 0.4mm; a segment of the industry is even using or considering a 0.25mm pitch. This has increased the use of stacked microvias in these designs. The process of stacking microvias has been practiced for several years in handheld devices; however, the devices generally do not operate in harsh conditions. Type 1 and Type 2 microvias have been tested over the years and have been found to be very reliable. We do not have enough test data for 3 and 4 stack microvias when placed on and off buried via. The main objective of this study was to understand the reliability of 3 and 4 stack microvias placed on and off a buried via....

Publisher: Firan Technology Group

The Long-term Shaping of the JTAG/Boundary-scan Standards

May 11, 2015 | Peter van den Eijnden, MD JTAG Technologies.

Originating from the last millenium, almost three decades ago, the introduction of surface mount packaging triggered a wave of changes throughout many aspects of electronics production. A small number of talented, innovative test engineers from various big players of the industry started to attend meetings to discuss the impact of that change of technology on their future test concepts for modern assemblies. The Joint Test Action Group was born....

Publisher: JTAG Technologies B. V.

Signal Transmission Loss due to Copper Surface Roughness in High-Frequency Region

Apr 30, 2015 | Elaine Liew, Mitsui Copper Foil Malaysia, Shah Alam Malaysia Taka-aki Okubo, Toshio Sudo, Shibaura Institute of Technology, Tokyo Japan Toshihiro Hosoi, Hiroaki Tsuyoshi, Fujio Kuwako, Mitsui Kinzoku Co., Ltd, Japan.

Higher-speed signal transmission is increasingly required on a printed circuit board to handle massive data in electronic systems. So, signal transmission loss of copper wiring on a printed circuit board has been studied. First, total signal loss was divided into dielectric loss and conductor loss quantitatively based on electromagnetic theory. In particular, the scattering loss due to surface roughness of copper foil has been examined in detail. And the usefulness of the copper foil with low surface roughness has been demonstrated....

Publisher: Mitsui Kinzoku Group

True Height Measurement in Solder Paste Inspection

Apr 29, 2015 | Dr. Subodh Kulkarni

SPI equipment is routinely used in Printed Circuit Board (PCB) manufacturing to monitor and control one of the most crucial steps affecting the finished quality of circuit board. Solder paste deposition is the key process in board assembly operations using SMT techniques. Our LSM™ system was the industry's first popular method of manually inspecting solder paste; our SE systems revolutionized SMT production by offering an automated method for performing in-process 3D inspection on the assembly line. SPI systems measure the height and volume of the solder pads before the components are applied and the solder melted, and when used properly, can reduce the incidence of solder-related defects to statistically insignificant amounts. Critical to the SPI measurement is the accuracy of the height measurement because that has a direct correlation with solder volume and defects....

Publisher: CyberOptics Corporation

Advanced modelling technique achieves near to zero set up time and minimal tuning

Apr 29, 2015 | Sean Langbridge

Statistical Appearance Modelling technology enables an AOI system to “learn real world variation” based on operator interaction with inspection task results. This provides an accurate statistical description of normal variation in a product. With modelling technology, the user does not have to anticipate potential defects as the system will “flag” anything outside the “normal production range”. And, since the system is programmed with real production variation, it is sensitive to small subtle changes enabling reliable defect detection. Autonomous prediction of process variation enables an AOI system to be set up from a single PCB with production-ready performance. Setup time can be < 15 minutes from data input to first PCB inspection making it an ideal solution for NPI and first-off verification....

Publisher: CyberOptics Corporation

Rework Challenges for Smart Phones and Tablets

Apr 23, 2015 | Paul Wood Advanced Product Applications Manager APR/ BGA Products OK International / Metcal.

Smart phones are complex, costly devices and therefore need to be reworked correctly the first time. In order to meet the ever-growing demand for performance, the complexity of mobile devices has increased immensely, with more than a 70% greater number of packages now found inside of them than just a few years ago. For instance, 1080P HD camera and video capabilities are now available on most high end smart phones or tablet computers, making their production more elaborate and expensive.

The printed circuit boards for these devices are no longer considered disposable goods, and their bill of materials start from $150.00, with higher end smart phones going up to $238.00, and tablets well over $300.00....

Publisher: Metcal

Stereo Vision Based Automated Solder Ball Height Detection

Apr 16, 2015 | Jinjin Li, Lina J. Karam; School of Electrical, Computer, & Energy Engineering, Arizona State University, Bonnie L. Bennett, Jeff S. Pettinato;Intel Corporation.

Solder ball height inspection is essential to the detection of potential connectivity issues in semi-conductor units. Current ball height inspection tools such as laser profiling, fringe projection and confocal microscopy are expensive, require complicated setup and are slow, which makes them difficult to use in a real-time manufacturing setting. Therefore, a reliable, in-line ball height measurement method is needed for inspecting units undergoing assembly. (...)

In this paper, an automatic, stereo vision based, in-line ball height inspection method is presented. The proposed method includes an imaging setup together with a computer vision algorithm for reliable, in-line ball height measurement....

Publisher: Intel Corporation

Good Schematics Lead to GOOD LAYOUTS

Apr 08, 2015 | Advanced Assembly

An electronic schematic describes the electrical connectivity of a piece of equipment or an entire system. It is made up of symbols that represent individual components and contains electrical and mechanical information and their related connectivity, along with other important data. Information contained within the schematic is packaged into a printed circuit board (PCB) where the mechanical footprint is placed onto the board and connectivity information is graphically displayed. The more accurate the information contained in the schematic is and the clearer it is presented, the more it contributes to a robust printed circuit board....

Publisher: Advanced Assembly, LLC.

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 Technologies 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