Counterfeit Electronic Parts

The threat posed by counterfeit electronic parts is increasing and presents exceptional challenges to equipment manufacturers when using commercial-off-the-shelf (COTS) products and/or when trying to mitigate the effects of obsolescence by buying from sources other than Original Equipment Manufacturers or their designated distributors who may no longer carry the part. The old adage know your supplier is still applicable, but it is not the solution to avoiding counterfeit electronic parts. Counterfeiters are becoming more sophisticated in their efforts and buyers often have to ensure that acceptance testing is performed at a level beyond what was typically considered adequate just a few years ago. As awareness grows as to how significant the counterfeit threat is, proactive manufacturers are instituting risk mitigation procedures both in their procurement and testing processes to reduce the risk of introducing counterfeit parts into their product lines.

Registration, Evaluation, Authorization and Restriction of Chemical (REACH) substances

REACH is a new European Community Regulation on chemicals and their safe use which became effective 1 June 2007 and will be phased in over eleven years. The aim of REACH is to improve the protection of human health and the environment through the better and earlier identification of the intrinsic properties of chemical substances. As a result, manufacturers will be required to gather information on the properties of their chemical substances and to register the information in a central database run by the European Chemicals Agency (ECHA) in Helsinki. In addition, manufacturers are responsible for managing the risks from chemicals used in the production of material and products and for providing safety information on the substances. The Regulation also calls for the progressive substitution of the most dangerous chemicals when suitable alternatives have been identified.

Lead-free & Tin Whiskers

For more that fifty years, electronics have been manufactured using tin-lead (Sn-Pb) solders and component termination finishes. Now, driven by the European UnionÂ’s RoHS (Reduction of Hazardous Substances) and other legislation, the global electronics manufacturing industry is rapidly transitioning to lead-free (Pb-free) processes and products. Although military-aerospace manufacturers are either not subject to the legislation or are covered by exemptions, their increasing dependence on COTS electronic parts and assemblies, makes them extremely vulnerable to the reliability risks associated with lead-free. There are a number of significant failure mechanisms associated with lead-free solders and termination finishes. Principal among these are the higher reflow temperatures associated with lead-free solders that can potentially damage circuit boards and electronic components, the susceptibility of solder joints to cracking and the growth of tin whiskers on pure tin termination finishes. Tin whiskers are the most insidious threat to todayÂ’s small geometry parts. They are electrically conductive hair-like filaments that can cause short circuits and have been responsible for an estimated loss of at least a billion dollars worth of satellites, missiles, and other electronic equipment. While most aerospace and high performance manufacturers and system integrators are attempting to prohibit the use of lead-free solders and finishes, the increasing cost of tin-lead products as their supplies diminish may, in cases, force at least a partial transition to lead-free and the associated high risk waivers of reliability requirements.

Tin Whisker Mitigation

The reliability threat posed by tin whiskers has promoted the development, particularly by DoD, of a number of potential means of partially mitigating the risks. These include the use of physical barriers, conformal coatings, underplating, heat treatments and reprocessing.

TMTI

Transformational Manufacturing Technology Initiative (TMTI) was a collaborative effort by The Best Manufacturing Practices Center Of Excellence (BMPCOE), the Center for Advanced Life Cycle Engineering (CALCE) Electronic Products and Systems Center, Corfin Industries, and Raytheon that successfully proved that a commercially available process for robotically reprocessing a number electronic package types to remove the pure tin finish on component leads and replace it with ‘whisker-safe’ eutectic tin-lead could be safely employed without damaging the parts.

Whisker-Tough Conformal Coating

Experiments have shown that, despite their ability to partially mitigate the growth and shorting potential of tin whiskers, all of the predominantly used conformal coatings can eventually be punctured by whiskers. The Missile Defense Agency is funding efforts to develop a ‘whisker-tough’ conformal coating that will provide all the benefits of a conventional coating while completely controlling tin whiskers.

DMSMS

Diminishing Manufacturing Sources and Material Suppliers (DMSMS), the impending or latent loss of the last known manufacturer or supplier of raw materials, production parts, or repair parts, is a vital threat to mission success and should be dealt with proactively and expeditiously. DMSMS program activities should be included as a regular analysis element of the Systems Engineering and Risk Management Program. Program office personnel should work closely with manufacturers early in the acquisition cycle to perform continuous market research on technology trends. Project Management should establish and maintain a barometer to monitor obsolescence while using open architecture design to facilitate insertion of new technology. These best practices can greatly assist project managers in reducing the risk of DMSMS impact to their programs.

Tin Whiskers

Tin whiskers are electrically conductive hair-like filaments of tin that unexpectedly protrude from pure tin finishes. They are responsible for a multitude of sporadic and/or permanent electronic malfunctions. With todayÂ’s shrinking circuit geometries, tin whiskers pose an even graver threat. They are responsible for electrical shorts in high-reliability electronics, resulting in an estimated loss of at least a billion dollars worth of satellites, missiles, and other electronic equipment. Tin whiskers are a detriment to any system demanding longevity and high reliability. The spontaneity of tin whiskers makes it difficult to understand exactly how, when, and why they materialize. Though industry lacks substantive knowledge about whisker formation, efforts are underway to combat its effects.

Robotic Solder Dip

When pure tin plating cannot be avoided, other mitigations must be investigated. One such mitigation is the robotic “re-coating” of lead-free component finishes with tin-lead. Robotically controlled solder pot dips have proven successful in replating pure tin finishes with tin-lead. When solder dipping is used, precautionary measures should be taken to prevent thermal degradation and loss of hermeticity. This technique would be used on select components.

PEMs

With military manufacturing suppliers declining, DoD has placed heavy emphasis on a transition toward commercial plastic encapsulated microcircuits. This controversial change to commercial Plastic Encapsulated Microcircuits (PEMs) has resulted from acquisition reform, a shrinking defense budget, a reduced supplier list, increased availability, and cost-effectiveness. Shortages of MIL-SPEC components are forcing PEMs into select military applications, despite some concerns. There are those who caution introducing PEMs into high reliability applications because of their limited temperature range, unknown performance and reliability data, rapid obsolescence, and product variability. Because of their reduced cost, size, and weight, the potential benefits from PEMs should not be overlooked. Nor should their increased selection availability, increased automated assembly methods, and continuous product improvement programs.

Pedigree

The pedigree process compiles and documents data on every facet of every component within a product. It includes when, how, and under what environmental conditions the components were manufactured, and whether or not process consistency was upheld. Pedigree scrutinizes every detail of a process, analyzing and identifying all stages within the process for potential errors or variability to ensure that they are isolated and removed. A responsible Pedigree guarantees traceability and documentation, and enables the manufacturer to improve quality and reduce variability. When good configuration management discipline is practiced, it is much easier to institute a Pedigree.

Forensic Failure Analysis

Following a failure, a systematic assessment of the Unit Under Test (UUT) should be conducted to identify the failure mode and the root cause(s). A failure data system should be employed to gather and process information, followed by dissemination of formal documentation of failure(s) for further evaluation by both the management team and engineering personnel. Analysis should be adequate to rationally develop and implement positive corrective actions that avoid repetition and costly down time. Within 30 days, failure analysis reports should be closed out to avoid recurrence of failures. Corrective actions should be monitored to ensure the removal of the failure cause(s) and should be readdressed if proven ineffective. Our staff is knowledgeable and experienced in forensic failure analysis, and is ready and willing to offer engineering expertise and technical support to meet the needs of your individual applications.

Science & Technology to Production

With the advent of Acquisition Reform, the rapid maturation of new technology, and the shrinking defense dollar, it has become increasingly more important to get new technology in the hands of the Warfighter as soon as possible. The military establishment no longer has the luxury of a deliberate, systematic, and prolonged development cycle for weapons systems; it takes too long and costs too much. New technologies must be developed into usable systems in a fraction of the time normally associated with the DoD standard acquisition cycle. At the same time, with the increased utilization of our military forces in rapid deployment scenarios, we can ill afford to put poorly developed weapons system in the hands of the Warfighter for them to “work out the bugs.” Their concentration must be on the mission, not the tools to accomplish it. Not all S&T projects, no matter how urgent the need may seem, are suitable candidates for rapid acceleration into production. Senior DoD management must be able to make the tough decision of which S&T projects that are urgently needed in the Fleet have the requisite technology maturity and the programmatic underpinnings to successfully transition directly into production. This is not a trivial decision. A set of entrance and exit criteria were developed for use in a tool intended to assist Senior Managers in 1) rapidly assessing the risks associated with the program, and 2) providing assistance to Senior Management in making informed decisions.

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