With industry studies showing that 30% of all electronic failures can be attributed to electrostatic damage, ESD control programs are an essential part of a quality process. And how extensive should the ESD control program be? That is determined by the ESD-sensitivity of the devices themselves and how they are handled.
One of the main reasons that companies deploy ESD control programs is to save money. Increased throughput and decreased scrap can yield a return on investment (ROI) of up to 1,000%.1 Another important reason is to comply with the requirements of customers and ISO 9000-type programs. Whatever reason, setting up and implementing an ESD control program will almost always produce favorable financial results.
Cost Reduction
Having ESD awareness and following through with a control program are essential in reducing failures. ESD can affect product reliability with catastrophic results due to latent degradation. Latent degradation is particularly expensive, requiring costly inspection and rework cycles in-house or causing product failure in the field. Maintaining good ESD controls will improve product throughput or yield, increase reliability in the field, and enhance customer satisfaction.
It is very important when designing and implementing an ESD control program to know the ESD susceptibility of the devices you are trying to protect. Classification of these devices should include the Human Body Model (HBM), the Machine Model (MM), and the Charged-Device Model (CDM) to properly characterize the sensitivity of the devices when handled at various locations within a facility.2 Proper device characterization helps to develop the most economical control program.
Examples of losses from ESD can be any of the following:
- Lost time.
- Loss of connection.
- Loss of data.
- Shocks to personnel.
- Upset to a system requiring a reboot.
- Damage to equipment.
To properly determine the ROI from your ESD control program, you must collect return, repair, and scrap cost data before and after implementation. Figure 1 (right) shows a sampling of data collected at several AT&T facilities by Terry O’Malley, a former AT&T ESD manager. The data speaks for itself. At the two facilities included in Figure 1, there were savings of more than 50% in return and repair costs after ESD control programs were initiated.
Figure 2 (below) represents the relative cost benefits of an ESD control program at Lucent Technologies. A typical ROI for a strict ESD control program, like that used at Lucent, could be as much as 1,000%.
Implementation
Protecting an ESD-sensitive device at all but one of the workstations is not acceptable. For an ESD control program to be effective, it must be comprehensive and followed with discipline throughout the manufacturing, transport, and storage cycles.
Management commitment is an important element of any effective ESD control program. Management must be involved to help improve quality and profits.
Major companies including AT&T, Motorola, Agilent Technologies, and IBM have successfully tracked ESD damage costs and the resulting benefits of their ESD control programs. These companies have determined that ESD control is an essential part of their success, one that results in significant investment payback.
But even with an ESD control program in place, a typical electronics company may lose 5% of revenue from all causes of product failure. Cost avoidance is the biggest issue when it comes to implementing an ESD control program.
Terry Welsher of Lucent Technologies stated that a typical payback on an ESD control program is 95:1. For every dollar invested in ESD control, $95.00 comes back as money saved.
Conclusion
There are many other factors that make up a well-designed ESD control program, such as employee training, ESD control products designed to protect the corresponding ESD-sensitive devices, program funding, management commitment, employee compliance with internal disciplines, and audits. The design of the program also should be well thought out to minimize unnecessary costs. A properly designed and successfully used ESD control program is a proven money saver with an ROI of up to 1,000% per year.
References
- Dangelmayer, G. T., ESD Program Management, 2nd Edition, Kluwer Academic Publishers, Boston, MA, 1999.
- The ESD Association, 7900 Turin Rd., Bldg. 3, Suite 2, Rome, NY 13440-2069, (315) 339-6937, www.eosesd.org.
Additional Resources
Allen, R., “How to Set Up an ESD Control Program,” EE-Evaluation Engineering, February 1999, pp. 112-123.
McAteer, O. J., Electrostatic Discharge Control, McGraw Hill Publishing, New York, 1990.
About the Author
Ryne C. Allen is the technical manager at ESD Systems, a division of Desco Industries. Previously, he was chief engineer and laboratory manager at the Plasma Science and Microelectronics Research Laboratory at Northeastern University. Mr. Allen is a NARTE-certified ESD control engineer, author of 27 published papers and articles, and a member of the ESD Association. He graduated from Northeastern University with B.S.E.E., M.S.E.E., and M.B.A. degrees. ESD Systems, 19 Brigham St., Unit 9, Marlboro, MA 01752-3170, (508) 485-7390, e-mail: [email protected].
Published by EE-Evaluation Engineering
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November 1999