Technical Program 2018
Professional Development Courses
Instructor: Martin Wickham, NPL
Instructor: Dr. Alec Feinberg, DfRSoftware
Wednesday Keynote AddressRalph C. Tuttle, Cree, Inc.
High Power LED Solder Joint Reliability
Under harsh environmental conditions like corrosion, radiation, high temperature and vibration, the aging of components is drastically accelerated. Dr. Kirsten Weide-Zaage of the University of Hannover will present on strategies for the identification of failure mechanisms and their interactions, test structure, test method development, specification and validation.
High failure rates are common when electronic systems are placed in harsh environments. Failed solder joints can occur from oxidation on component terminations. Tony Boswell of Retronix Limited will present on preparing ICs and Components so they will survive when placed in harsh environments.
As the demand for high interconnect solutions at the circuit board level increase, there must be performance improvements in components, interconnects and substrates. Martin Wickham of NPL will present research on coating systems for organic PCBs that are designed to operate at 250°C. The research finds that there is a reduction in oxidation rates to exposed metals in both the inner and outer layers within multilayer structures.
Alternative solder alloys designed for higher temperatures are needed. Mathias Nowottnick of the University of Rostock will present on transient liquid phase sintering research by combining solid copper powder and liquidus SnAgCu solder. This novel intermetallic has a melting point of 415°C. This research finds that transient liquid phase sintering can be used to develop high temperature alloys that work at higher temperatures. This contribution will show examples for manufacturing, achievable properties and possible applications.
Improved die attach alloys that achieve high reliability in power electronic devices exposed to harsh environments are needed. Suresh Telu will present the use of micro-alloying additives that modify bulk allow properties, solderability and solder joint strength. The research finds that micro-alloying additions reduce creep and fatigue life as compared to high Pb alloys.
With the increase electrification of automotive drive train, autonomous vehicles and ADAS (Advanced Driver Assist Systems), reliability drivers have intensified. Karthik Vijay of Indium Corporation will present on a novel solder alloy that exceeds performance requirements as compared to SAC305 alloys. Research finds better creep resistance and improved fatigue resistance during thermal cycling.
Voiding within the solder joint is a concern on electronics used for automotive, power electronics, LED, electrical conductivity and thermal dissipation performance. Emmanuelle Guene of Inventec Performance Chemicals will present on low voiding lead-free solder paste for high reliability applications. Reliability data using IPC Test Methods and the Bono test data will be presented.
Quantification of ionic contamination present on electronic assemblies is of extreme importance, especially when the end product functions within harsh environments. Marietta Lemieux of STI will present research on detection levels of ionic contamination trapped under leadless and BTC components. The data finds that the extraction time is an important consideration when qualifying and validating levels of contamination on production assemblies.
Electrochemical failure modes increase when ionic contamination is mobilized on a board assembly under environmental stress. Dr. Mike Bixenman of KYZEN Corporation will present advanced methods for characterizing ionic contamination under leadless component bodies. The data finds that these test methods can be implemented at the assembly site to characterize the reliability of incoming bare boards, soldering materials, leadless and bottom terminated components.
The use of X-ray technology to inspect for the presence of voids enables a non-destructive analysis. David Bernard will present on the Advances in 2D and 3D (CT) X-Ray inspection. Recent developments enable limited angle computer tomography (CT) as well as the use of full CT algorithms to improve analysis clarity to locate the source of voiding problems.
There is mounting evidence that as PCB component density increases, so does the sensitivity of the circuit to ionic contamination. There have been many industry examples where manufacturers have relied on ionic contamination testers, yet still had product that failed in service. Both OEMs and EMS companies need improved methods for developing “Objective Evidence” centered on the concept of a Qualified Manufacturing Process. To address this issue, Doug Pauls from Rockwell Collins will present an overview on Global Change in Ionic Cleanliness Requirements.
Removal of process residues is a common practice to reduce electrochemical interactions. The use of miniaturized components may violate minimum electrical clearance for devices exposed to harsh environments. Mike Konrad of Aqueous Technologies will present on cleanliness requirements needed to improve the reliability of printed circuit assemblies.
In highly humid environments, there is a greater concern on electronics robustness and signal integrity. Due to the need to reduce the power consumption of electronic modules, switching thresholds within high humidity environments decrease, which increases the propensity for leakage currents. Dr. Helmut Schweigart of Zestron, in collaboration with leading automotive tier 1 suppliers, will present research that allows an OEM to calculate switching threshold data on active devices that are exposed to harsh environments.
Significant performance and reliability challenges exist for harsh environment electronics within the automotive, power electronics, oil & gas, and aerospace applications. Under varying harsh operating environments, the life expectancy of electronic components and systems reduces exponentially if they are not designed, packaged, and protected appropriately. Dr. Rakesh Kumar of Specialty Coatings will present on thermally-stable, vapor-phase conformal coating for protection of electronics in harsh environments.
Highly dense assemblies are commonly packaged in designs that are permeable to moisture. While operating in hostile environments, the thickness and coverage variability of conformal coating over components impacts reliability. Phil Kinner of Humiseal will present research that compares and contrasts coating thickness to help the assembler determine optimum levels needed to withstand harsh environments. The attendee will gain insight into coating types, properties and reliability expectations.
Area array components, such as Ball Grid Arrays (BGAs), Chip Scale Packages (CSPs) and Flip Chip (FCs), then to add complexity to conformal coating processes. Previous studies have shown that the presence of conformal coatings under an area array component can induce solder joint failure. Dave Hillman of Rockwell Collins will present on how conformal coatings impact solder joint integrity of these advanced packaging. The research finds that some of the coating configurations degraded component reliability while others improved reliability.
Thursday Keynote AddressAndreas Middendorf, Ph.D., Fraunhofer IZM
Electronics and Automotive Applications
Electronic products may be subjected to thermal excursions resulting from the power on/off cycling and changes in the environment temperature. The board geometry and architecture can affect the thermal-mechanical reliability of the PCB materials. Dr. Eric Cotts from Binghamton University will present on PCB Materials and Fabrication. Dr. Cotts will share his thoughts on designing for excellence.
The plastic package that houses integrated circuits can degrade when exposed to high temperatures. Erik Spory of Global Circuit Innovations will present on a hermetic ceramic package design that provides a die pad surface for applications up to 250°C without connectivity degradation. Mr. Spory will also reference this technology option for use into other applications which expose IC to harsh environments.
With technology thrusts into automotive and aviation, electronics need to be designed to operate reliably at temperatures between 150°C and 175°C. Dr. Craig Hillman of DfR Solutions will present on insights and tradeoffs in designing passives, crystals, magnetics, discretes, integrated circuits, connectors, PCBs and solders to operate reliability within high temperature environments. Dr. Hillman will show how Point of Failure models can be sued to understand the risks of high temperature environments over time and how to effectively mitigate those risks through circuit design, derating and material selection.
The demand for electro-mobility technologies and solutions within the automotive industry has rapidly increased with the emergence of electric and autonomous vehicles. These applications expose the electronics to higher voltages. Kerstin Lux, a Ph.D. candidate from Bosch, will present on humidity induced failure mechanisms on electronics during high voltage load. Ms. Lux will present research that investigated the behavior of PCBs built with different material sets under high-voltage and high humidity load conditions. A model of the electrochemical reactions under high voltage and humidity conditions will be presented.
High power LED and automotive electronics must endure high temperature, thermal stresses, vibration and other harsh conditions. Dr. Maalekian of AIM Solder will present on improved solder alloy reliability and mechanical stability using micro-applying elements. The research from this work find that the addition of micro alloying dopants reduce the alloys temperature gradient’s while improving thermal fatigue and reliability.
When exposed to high temperatures stresses, there is the potential for solder alloy cracking and delamination. Graham Wilson of Indium Corporation will present on solder printed over a metal mesh preform to increase the reliability between the substrate and baseplate within IGBT Modules. The research finds that increased standoff improves the homogenous solder layer. Mr. Wilson will present research findings that improve solder reliability and overcome thermal fatigue and solder delamination.
iNEMI is co-hosting the final session of the conference, which will focus specifically on automotive electronics. Lothar Henneken, Ph.D. of Robert Bosch GmbH, will present recent updates of the IPC-A610 Standard's Automotive Addendum.
This session includes an interactive discussion with the following panel of experts:
The session closes with Breakout Groups on the following topics: