Nov 30, 2016 | Edward Arthur; Raytheon Company, Charles Busa, Wade Goldman P.E., Alisa Grubbs; The Charles Stark Draper Laboratory, Inc.
The use of microvias in Printed Circuit Boards (PCBs) for military hardware is increasing as technology drives us toward smaller pitches and denser circuitry. Along with the changes in technology, the industry has changed and captive manufacturing lines are few and far between. As PCBs get more complicated, the testing we perform to verify the material was manufactured to our requirements before they are used in an assembly needs to be reviewed to ensure that it is sufficient for the technology and meets industry needs to better screen for long-term reliability. The Interconnect Stress Testing (IST) protocol currently used to identify manufacturing issues in plated through holes, blind, or buried vias are not necessarily sufficient to identify problems with microvias. There is a need to review the current IST protocol to determine if it is adequate for finding bad microvias or if there is a more reliable test that will screen out manufacturing inconsistencies.
The objective of this research is to analyze a large population of PCB IST coupons to determine if there is a more effective IST test to find less reliable microvias in electrically passing PCB product and to screen for manufacturing deficiencies. The proposed IST test procedure will be supported with visual inspection of corresponding microvia cross sections and Printed Wiring Assembly (PWA) acceptance test results. The proposed screening will be shown to only slightly affect PCB yield while showing a large benefit to screening before PCBs are used in an assembly....
Nov 23, 2016 | Tom Nordman, Pasi Rahikkala
As we wirelessly connect more and more devices to the Internet, electronics engineers face several challenges, including how to package a radio transmitter into their existing device real estate and how to make increasingly smaller devices. They’re also striving to meet consumer demand for Internet of Things (IoT) products that are ergonomically easy to use and unobtrusive to the environment.
This whitepaper explores the challenges that come with designing connected devices into increasingly smaller products, specifically antenna integration, and how system-inpackage modules can help....
Publisher: Silicon Labs
Nov 17, 2016 | Greg Caswell, Melissa Keener
Since 2006 RoHS requirements have required lead free solders to take the place of tin-lead solders in electronics. The problem is that in some environments the lead free solders are less reliable than the older tin-lead solders. One of the ways to solve this problem is to corner stake, edge bond or underfill the components. When considering what mitigation technique and material to use, the operating conditions must be characterized. The temperature range is important when selecting a material to use since the glass transition temperature (Tg) and coefficient of thermal expansion (CTE) are important properties. If improperly chosen, the mitigation material can cause more failures than an unmitigated component....
Publisher: DfR Solutions
DfR Solutions has world-renowned expertise in applying the science of Reliability Physics to electrical and electronics technologies, and is a leading provider of quality, reliability, and durability (QRD) research and consulting for the electronics industry.
College Park, Maryland, USA
Nov 17, 2016 | Dr. Mary Liu and Dr Wusheng Yin
With increasing LED development and production, thermal issues are becoming more and more important for LED devices, particularly true for high power LED and also for other high power devices. In order to dissipate the heat from the device efficiently, Au80Sn20 alloy is being used in the industry now. However there are a few drawbacks for Au80Sn20 process: (1) higher soldering temperature, usually higher than 320°C; (2) low process yield; (3) too expensive. In order to overcome the shortcomings of Au80Sn20 process, YINCAE Advanced Materials, LLC has invented a new solderable adhesive – TM 230. Solderable adhesives are epoxy based silver adhesives. During the die attach reflow process, the solder material on silver can solder silver together, and die with pad together. After soldering, epoxy can encapsulate the soldered interface, so that the thermal conductivity can be as high as 58 W/mk. In comparison to Au80Sn20 reflow process, the solderable adhesive has the following advantages: (1) low process temperature – reflow peak temperature of 230°C; (2) high process yield – mass reflow process instead of thermal compression bonding process; (3) low cost ownership. In this paper we are going to present the die attach process of solderable adhesive and the reliability test. After 1000 h lighting of LED, it has been found that there is almost no decay in the light intensity by using solderable adhesive – TM 230. ...
Publisher: YINCAE Advanced Materials, LLC.
Nov 10, 2016 | Qiujiang Liu; Baidu, Inc., Prabjit Singh; IBM
The demand for compute capability is growing rapidly fueling the ever rising consumption of power by data centers the worldwide. This growth in power consumption presents a challenge to data center total cost of ownership. Free-air cooling is one of the industrial trends in reducing power consumption, the power usage effectiveness (PUE) ratio, and the total cost of ownership (TCO). Free-air cooling is a viable approach in many parts of the world where the air is reasonably clean. In Eastern China, the poor quality of air, high in particle and gaseous contamination, is a major obstacle to free-air cooling. Servers exposed to outside air blowing in to data centers will corrode and fail at high rate. The poor reliability of hardware increase TCO dramatically.
This paper describes a corrosion resistant server design suitable for reliable operation in a free-air cooling data center located in Eastern China where the indoor air quality can be as poor as ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) severity level G3. An accelerated corrosion test method of verifying hardware reliability in the ASHRAE severity level G3 environment is also described....
Publisher: IBM Corporation
Nov 10, 2016 | Rob Boyd, Senior Product Manager, Schleuniger, Inc.
It goes without saying that every manufacturer wants to ensure they are producing a quality product. Standards and specifications from various organizations provide a guideline from which manufacturers can measure different areas of quality, while also providing the end user with the reassurance that they are purchasing a trustworthy, long-lasting product. Within the wire processing industry there are many standards that manufacturers may choose or be required to adhere to. These standards and specifications are constantly evolving and increasing in detail, especially as monitoring technology improves. ...
Publisher: Schleuniger, Inc.
Nov 09, 2016 | Dave Selestak, Alex Berlin, and Carla Loeffler
Nordson MARCH found a solution for a manufacturer of PCBAs used in ruggedized environments. Read how plasma prior to conformal coating reduced defects and virtually eliminated coating-related failures....
Publisher: Nordson MARCH
Nordson MARCH is the global leader in plasma cleaning equipment and plasma applications technology. The company has designed and manufactured plasma equipment for more than 30 years.
Concord, California, USA
Nov 08, 2016 | Simon Garrison
Over time most PCB designs need to change – a mistake is found, or a part becomes obsolete, etc. Typically once the changes are complete, a new set of manufacturing files (Gerbers, NC Drill files, BOM, Pick and Place, etc) are generated, and the updated design is stored as separate version within a version control system. Using a version control system makes it possible for design teams to go back later and compare differences between design versions. ****** http://www.numericalinnovations.com/blogs/news/gerber-comparisons-between-revisions-of-the-same-board *****...
Publisher: Numerical Innovations
Nov 03, 2016 | Adam Khalifa, Zhaoli Gao, Amine Bermak, Yi Wang, Leanne Lai Hang Chan
We present a novel method for fabricating a high-density carbon nanotube microelectrode array (MEA) chip. Vertically aligned carbon nanotubes (VACNTs) were synthesized by microwave plasma-enhanced chemical vapor deposition and thermal chemical vapor deposition. The device was characterized using electrochemical experiments such as cyclic voltammetry, impedance spectroscopy and potential transient measurements. Through-silicon vias (TSVs) were fabricated and partially filled with polycrystalline silicon to allow electrical connection from the high-density electrodes to a stimulator microchip.
In response to the demand for higher resolution implants, we have developed a unique process to obtain a high-density electrode array by making the microelectrodes smaller in size and designing new ways of routing the electrodes to current sources....
Publisher: Hong Kong University of Science
Oct 27, 2016 | Jose Becerra, Dennis Willie and Murad Kurwa
Press-fit technology is a proven and widely used and accepted interconnection method for joining electronics assemblies. Printed Circuit Board Assembly Systems and typical functional subassemblies are connected through press-fit connectors.
The Press-Fit Compliant Pin is a proven interconnect termination to reliably provide electrical and mechanical connections from a Printed Circuit Board to an Electrical Connector. Electrical Connectors are then interconnected together providing board to board electrical and mechanical inter-connection. Press-Fit Compliant Pins are housed within Connectors and used on Backplanes, Mid-planes and Daughter Card Printed Circuit Board Assemblies. High reliability OEM (Original Equipment Manufacturer) computer designs continue to use press-fit connections to overcome challenges associated with soldering, rework, thermal cycles, installation and repair.
This paper investigates the technical roadmap for press fit technology, putting special attention to main characteristics such, placement and insertion, inspection, repair, pin design trends, challenges and solutions. Critical process control parameters within an assembly manufacturing are highlighted....
Publisher: Flex (Flextronics International)