Dec 27, 2013 | Mario Scalzo Senior Technical Support Engineer CSMTPE, Six-Sigma Black Belt
The head-in-pillow defect has become a relatively common failure mode in the industry since the implementation of Pb-free technologies, generating much concern. A head-in-pillow defect is the incomplete wetting of the entire solder joint of a Ball-Grid Array (BGA), Chip-Scale Package (CSP), or even a Package-On-Package (PoP) and is characterized as a process anomaly, where the solder paste and BGA ball both reflow but do not coalesce. When looking at a cross-section, it actually looks like a head has pressed into a soft pillow. There are two main sources of head-in-pillow defects: poor wetting and PWB or package warpage. Poor wetting can result from a variety of sources, such as solder ball oxidation, an inappropriate thermal reflow profile or poor fluxing action. This paper addresses the three sources or contributing issues (supply, process & material) of the head-in-pillow defects. It will thoroughly review these three issues and how they relate to result in head-in pillow defects. In addition, a head-in-pillow elimination plan will be presented with real life examples will be to illustrate these head-in-pillow solutions....
Publisher: Indium Corporation
Dec 19, 2013 | Rick Gunn, Vice President of Engineering / Chief Technology Officer, Nextek Incorporated.
With the adoption of RoHS and implementation of Lead Free solders a major concern is how this will impact reliability. Both commercial and military hardware are impacted by this change even though military hardware is considered exempt from the requirements of RoHS. As the supply chain has moved to the new lead free alloys both markets are being forced to understand these impacts and form risk mitigation strategies to deal with the change. This paper documents the effect of mixing Leaded and Lead Free alloys on BGA devices and how this impacts reliability. Three of the most common pitch BGA packages are included in the study to determine if the risk is the same as pitches decrease...
Dec 11, 2013 | Greg Caswell, Sr. Member of the Technical Staff, DfR Solutions
Today's analyses of electronics reliability at the system level typically use a "black box approach", with relatively poor understanding of the behaviors and performances of such "black boxes" and how they physically and electrically interact (...) The incorporation of more rigorous and more informative approaches and techniques needs to better understand (...) Understanding the Physics of Failure (PoF) is imperative. It is a formalized and structured approach to Failure Analysis/Forensics Engineering that focuses on total learning and not only fixing a particular current problem (...) In this paper we will present an explanation of various physical models that could be deployed through this method, namely, wire bond failures; thermo-mechanical fatigue; and vibration....
Publisher: DfR Solutions
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, United States
Dec 05, 2013 | Susie Krzmarzick, John Dzarnoski, Yangjun Xing.
The functionality of electronic devices continues to increase at an extraordinary rate. Simultaneously consumers are expecting even more and in ever smaller packages. One enabler for shrinking electronics has been the flexible circuit board that allows the circuit board to fit a wide variety of shapes. Flexible printed circuits (FPC) have the capability to be very thin and can have unpackaged components directly attached using surface mount technology (SMT) and flip chip on flex technologies. Bare die can also be thinned and attached very close to the circuit board. However one caveat of high density flexible circuit boards with thin die is that they can be very fragile. The use of back side films and underfill can protect the die making circuits more robust. For underfill to work well it requires good adhesion to the circuit board which can mean that flux residues under the die normally must be removed prior to underfilling. ...
Publisher: Starkey Hearing Technologies
Nov 27, 2013 | Olivier Vendier, Jean-Louis Cazaux, Jean-Luc Lortal; Thales Alenia Space.
The need in complexity for microwave space products such as active BFNs (Beam Forming Networks) is increasing, with a significantly growing number of amplitude / phase control points (number of beams * numbers of radiating elements). As a consequence, the RF component’s package topology is evolving (larger number of I/Os, interconnections densification ...) which directly affect the routing and architecture of the multilayer boards they are mounted on. It then becomes necessary to improve the density of these boards (...) This paper will present the work performed to achieve LCP-based high density multilayer structures, describing the different electrical and technological breadboards manufactured and tested and presenting the results obtained....
Nov 21, 2013 | Chrys Shea, Shea Engineering Services; Ray Whittier, Vicor Corporation
Previous experimentation on a highly miniaturized and densely populated SMT assembly revealed the optimum stencil alloy and flux-repellent coating for its stencil printing process. Production implementation of the materials that were identified in the study resulted in approximately 5% print yield improvement across all assemblies throughout the operation, validating the results of the initial tests. A new set of studies was launched to focus on the materials themselves, with the purpose of optimizing their performance on the assembly line (...) Results of the prior tests are reviewed, and the new test vehicle, experimental setup and results are presented and discussed....
Publisher: Shea Engineering Services
Nov 14, 2013 | Nordson Asymtek
Understanding accuracy and repeatability is an important step to analyze fluid dispensing system performance. They can also be prone to misinterpretation when reviewing a product specification. A dispensing motion system can be made to perform better or worse under different operating conditions. This article will explain accuracy and repeatability, and how they can be applied to different specifications. It will also discuss key considerations when interpreting accuracy and repeatability for decision making....
Publisher: Nordson ASYMTEK
A leader in automated fluid dispensing, jetting and conformal coating. Products range from benchtop dispensers and stand-alone dispensing workstations to fully automated, in-line conveyorized systems.
Carlsbad, California, United States
Nov 07, 2013 | Jorge Maornla.
Today’s customers are more enlightened and aware demanding quality and compact electronics products at competitive prices. Today when a single word spreads out so quickly, no company can afford to put their reputation at stake by manufacturing substandard products....
Publisher: American Progressive Circuits,Inc,
APC is a leading electronics company which committed to provide streamlined PCB manufacturing & Design Services.
ADDISON, Illinois, United States
Nov 06, 2013 | Dr Lee Hitchens
The set up of a turnkey conformal coating production line or facility, whether it is a batch or inline process, has many similar characteristics. Whether the coating application is based around a high volume selective coating robot, a batch dip coating system or a spray booth, the process requirements tend to be the same. This bulletin reviews the potential needs of the facility, including the process controls, environmental needs and health and safety issues and provides some starting points for a new facility....
Publisher: SCH Technologies
SCH Technologies offers a range of conformal coating solutions including global subcontract conformal coating and parylene services, equipment & systems,conformal coatings, consultancy & training.
Barnsley, United Kingdom
Oct 31, 2013 | Judy Warner, Chris Savalia; Transline Technology, Michael Ingham; Spectrum Integrity
Multilayer printed circuit boards (PCBs) that utilize high performance materials are inherently far more challenging for a fabricator to build, due to significant material property differences over standard epoxy glass FR4. These unique material characteristics often require higher processing temperatures, special surface treatments (to aid in hole and surface plating), they possess different expansion properties, making layer-to-layer registration more difficult to control, and require many other unique considerations....
Publisher: Spectrum Integrity, Inc.
Spectrum Integrity is a full service Engineering Design Service Firm. We are a Solution Provider for companies requiring outstanding hardware designs for advanced RF, High-Speed, and Semiconductor Test applications.
Simi Valley, California, United States