||By Charles Wells, Customer Support and Glen Olaes, X-ray Product Manager, FocalSpot, Inc., San Diego, CA
Most people in the EMS Industry are acutely aware of the growing problem of counterfeit and substandard electronic components within the supply chain, as well as the headaches they cause. While industry and governments are working diligently in addressing counterfeit abatement, you may already have one of the most useful tools in combating phony parts in place, on your production floor.
Some would suggest that you need not concern yourself with counterfeits if you simply follow this best practice: buy direct from manufacturers and authorized distributors only. But for many, the day-to-day realities of procurement demand that they enter the open market. Organizations such as the Independent Distributors of Electronics Association (IDEA) are already addressing the problem by developing an inspection protocol aimed at intercepting counterfeit and substandard parts before they reach your receiving departments, and many of the most reputable distributors are adopting their IDEA-STD-1010-A visual inspection standard. Still others, such as NexGen Digital, are going beyond visual inspection by incorporating advanced devices such as FocalSpot's X-ray inspection systems, XRF, and decapsulation systems in order to verify authenticity of manufacture prior to resale distribution.
Since the advent of the BGA package, many OEMs and CMs have used x-ray as part of a quality manufacturing process. Your existing x-ray system can be a valuable tool in assessing the authenticity and quality of your incoming parts orders. Among the tools being employed in exposing misrepresented electronic components, x-ray is unique in its ability to look inside parts without destroying them, and in fact, without even removing them from ESD packaging, trays, or tubes.
Utilizing your existing x-ray inspection system as part of your receiving process may be prudent when sourcing components on the open market, particularly if the distributors with whom you are working have yet to adopt x-ray inspection as part of their QC process. With little training, your receiving team will quickly develop the skills and knowledge necessary to check incoming parts not only for authenticity, but also for important quality indicators.
An effective x-ray inspection protocol includes overview inspection (Top Down View) to determine: die presence/absence; die dimensions (requires image processing measurement tools); die attach material presence/absence;leads, paddle, and bondwire layout; bent or deformed leads.
Magnified views will discover: die attach cracks/voids; molding cracks/voids (using low kV); proper ball/wedge bond attachment (requires high magnification and resolution).
Side and oblique views show die thickness (requires image processing measurement tools) and bondwire geometry.
Provided your system has a large enough field of view, it is best to start with the overview, which will quickly expose gross counterfeits in which the die or other critical features may be absent. If your image processor allows, you may wish to apply measurements to features such as the die or paddle, which can be especially useful when a known good part is available for comparison. Archiving the resulting images can also build a powerful resource for future comparisons.
Outright counterfeits, of course, are not the only threat. Substantial numbers of refurbished components are finding their way back into the supply chain, posing as new (authentic) or often impersonating higher cost components (re-marked). Still others may reach your dock as scavenged rejects or as the product of unauthorized production runs ("Third Shift").
X-ray inspection exposes a number of quality indicators which can aid in preventing substandard parts from corrupting your products. An overview image, as described earlier, can reveal bent leads, cracks or voids in the component body, as well as die attach voids and cracking. Magnified and angled or oblique views may show defects in bondwire quality, whether they be broken or bent, demonstrate inconsistent loop height, or are poorly attached.
Particular attention should be paid to cracks or voids. Such features within the die attach material can be indicative of previous thermal cycling and thus suggest the possibility that the part has been refurbished. While components with substantial die attach defects may pass functional test, they will likely suffer from limited reliability. In addition, components that have voids within the plastic body or within the die attach material are often rejected by the manufacturer. Still these parts can find their way into the supply chain by way of unscrupulous employees or scavengers.
Small cabinet, manual x-ray systems are well suited for this type of inspection, and are surprisingly affordable. If such a system prevented a single incident of counterfeit parts reaching your production floor, it would be well worth the investment. Consider dedicating such a system to receiving, and it can also serve as a valuable backup in the event your production system is down. Until your suppliers widely adopt x-ray inspection as part of their quality process, consider utilizing your existing x-ray system in your receiving process. Doing so will provide an added benefit to your customers, and increase your competitive advantage.
Contact: FocalSpot, Inc., 9915 Businesspark Ave., Ste. A, San Diego, CA 92131. 858-536-5050 fax: 858-536-5054 E-mail: firstname.lastname@example.org Web: http://www.focalspot.com