Several methods exist to determine cleanliness of printed wiring assemblies. This presentation will describe the common methods used for determining cleanliness of printed wiring assemblies. The test methods used for extraction techniques such as resistivity of solvent extract and ion chromatography will be identified and results from actual tests will be analyzed. Electrochemical methods will be presented including electro migration and surface insulation resistance methods. Results from actual testing will be reviewed and interpreted from a user’s perspective. From the interpretation of the results of testing,potential sources of contamination will be identified. The detection of certain types of residues including ionic and non-ionic contaminates which are commonly found as a result of electronics assembly process. Sources of common contaminates such as: residual plating chemistry,flux residues,surfactants,oils.

As people become more concerned about the global outbreaks of various strains of influenza,more precautions are being taken with respect to personal hygiene. A common precaution involves the use of hand sanitizer solutions or similar germicidal agents. For manufacturers of electronic assemblies,this may mean a potential transfer of these solutions/agents to the surface of the assemblies as a contaminant material. Similarly,many production employees in the electronics industry deal with harsh chemicals,which often remove hand oils,resulting in chapped or dry skin. The use of hand lotions may or may not be allowed,depending on the manufacturer,with a similar concern regarding transfer of unknown chemicals to the assembly surface. This paper is an examination of some typical hand sanitizers and hand lotions and their impact on high reliability electronic hardware.

The growing complexity of electronic assemblies increases the cleaning challenge due to miniaturization,lower component gaps,and improved flux designs. The need to remove ionizable contaminants is critical to production yields and reliability. As user’s source cleaning equipment and cleaning agents to meet these increased cleaning demands,a number of options must be considered such as batch versus inline,cleaning agent designs,impingement options,controlling the cleaning agent,rinsing,drying,and waste management. The purpose of the research paper is to provide operational data for integrating aqueous cleaning equipment and cleaning agent for maximum performance. The conference participates will gain knowledge of batch and inline aqueous cleaning equipment designs,cleaning agents,energy sources for penetrating low residue gaps,air management,controlling the cleaning agent,managing rinse water,and waste management.

Advancing technology frequently requires an accompanying advancement in materials technology. Recently,these advances are also driven by changes in environmental legislation as well. Specifically,the RoHS legislation has mandated a move away from lower-temperature Sn/Pb solders to higher reflow temperature SAC alloys on the PCB assembly. This change in reflow temperature drives changes to materials used inside packages as well. In addition to material composition changes,component geometry,spacing,and design drive new process capability. In this paper we will discuss the testing
and evaluation of a new die attach solder paste material,the design considerations for both process and alloys. We will discuss the requirements for these materials used in high power packages and the material properties needed to deliver on these requirements.

As margins on electronics technology have continued to erode,an increasing number of organizations have implemented design for reliability practices to ensure device performance while meeting tight product development guidelines. There are numerous aspects of DfR principles,including specification development,part selection and derating,design review by failure mod (DRBFM),and physics of failure (Pof). Often overlooked by the "science of success," Pof will play a crucial role in future design activities as an increasing number of technologies are designed with limited lifetimes. Components of concern have broadened from the traditional LEDs and electrolytic capacitors into sub-90nm integrated circuits and solder joint fatigue. This presentation will provide a history and overview of PoF and where it fits into the overall scheme of DfR. Of critical importance will be a discussion on which organizations and standards bodies will start to require PoF and how to implement PoF into your design activities to ensure product success and compliance with the next generation of industry specifications.

High reliability applications in the military and aerospace industry require reliable solder finish
identification on components within the supply system of DoD,NASA,and many other organizations. Consumer products and military/aerospace industry commonly share the same suppliers of electronic components. The RoHS regulation has forced those suppliers to provide lead free solder solutions. As a result,components with many different solder finishes are now available. Compatibility issues,among
those various solder finishes such as melting temperatures,tin whisker formation,stress fracturing etc. create a serious reliability problem the military/aerospace industry is trying to overcome. A new technique has been developed to reliably identify unknown samples or materials utilizing XRF instrumentation. The technique will help in identifying quickly and reliably bulk and surface finish solders of individual components as well as populated boards. This new identification tool can be used for any application and is particularly helpful if suitable standards are unavailable. Fischer Technology will present practical examples for solder analyses. The method will also assist the user to identify the correct measurement application which can then be used to make a full quantitative analysis if desired.

BGA’s,ceramic capacitors,and similar strain sensitive components are used extensively throughout the automotive and consumer electronics industries. Unfortunately these components can be easily damaged when exposed to excessive board strain and flex and induce microscopic defects within the components that typically are undetectable. Additional thermal and mechanical cycling can cause these defects to propagate over time and ultimately lead to component failure,product failure,and customer dissatisfaction. Since defect detection is ineffective,defect prevention is the key to success.
This paper will review in depth the various failure modes,identify high risk assembly processes,and outline the critical prevention strategies that need to be implemented to produce a defect-free quality product. Topics will cover product design,process design,and verification strategies.

Like many other electronics industries,the automotive electronics industry has long been concerned about ESD. As dramatically seen in the news today,quality recalls can detrimentally affect the faith and loyalty that a customer has for a company’s products. Automotive collision avoidance radar systems,Telematics and some audio products are currently made with parts that are extremely sensitive to ESD. Robust ESD controls at the vehicle electronic system suppliers are needed to protect their customers from ESD. This in most cases can be done by complying with the ESD control industry’s standards ANSI/ESD S20.20 and IEC 61340-5-1. The ESD controls built around these standards have been successfully used for over the past 20+ years,but will need improved upon for more sensitive future devices. In addition,ESD control issues at the assembly plant will also be discussed as current guidelines may need to be improved given the growing trend for more sensitive electronics in vehicles and at the same time,the explosion of even more vehicle parts made from static generative plastics.

• Genesis in December 2008
• Follow-up discussions APEX 2009
• Input received from SMEs
• Conference Call July 22,2009
• Discussions IPC Midwest 2009
• First white paper issued by IPC SPVC June 2010

Using X-ray imaging,solder corrosion,resembling metal migration,had been observed under QFN (Quad Flat No-Lead package) devices and chip resistors on circuit boards that were processed with two SAC 305 alloy solder pastes after 500 hours of exposure to 85ºC and 85% R.H. with no applied voltage. Analysis of the material under QFN’s by SEM (scanning electron microscopy) and energy-dispersive X-ray spectroscopy showed it was primarily a tin compound. This phenomenon was only observed for components that had a relatively large quantity of flux residue trapped underneath them. Further investigation was made using six different SAC305 alloy solder pastes and solder paste test coupons with copper OSP and NiAu metal surface finishes. The test coupons were examined with X-ray imaging before exposure to 85ºC and 85% R.H. and then after 250,500,750 and 1000 hours of exposure. On the NiAu boards,tin corrosion was observed for five of the six pastes after 250 hours exposure,and after 750 hours exposure for the sixth paste. For OSP boards,three pastes showed corrosion after 250 hours,an additional paste after 750 hours,and two pastes showed no corrosion after 1000 hours exposure. The corrosion is dependent on solder paste flux chemistry,solder alloy and the board’s metal finish. The investigation discussed here concerns three solder paste flux chemistries,SAC305 and 63 Sn 37 Pb alloys and 3 reflow conditions. Flux chemistry had the greatest effect on tin corrosion under QFN components; however SAC305 corroded faster than 63 Sn 37 Pb. Reflow conditions had almost no effect.