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Electro Static Discharge Basics

  1. 1. Electrostatic Discharge ESD Basics and Protection
  2. 2. About Transforming Technologies Transforming Technologies is a leading solution provider for static control in the electronics industry. We offer over 10 years experience in providing electrostatic solutions to manufacturing facilities; protecting products and processes from the many serious problems associated with static electricity. Headquartered in Toledo, OH, USA, Transforming Technologies we offer a wide range of unique and exceptional ESD products to prevent, eliminate an monitor electrostatic charges. We provide comprehensive knowledge of electrostatic issues, and above all outstanding, friendly service. We call it Static Care™.
  3. 3. What is ESD?  ESD definition  Common causes of ESD  Sources of ESD  Types of ESD damage Photo of ESD arcing from finger to component
  4. 4. ESD Definition . ESD – Electrostatic Discharge: The transfer of an electrostatic charge between bodies at different electrical potentials.  Also referred to as static electricity  Electrostatic charge is most commonly created by the contact and separation of two materials which results in Tribocharging
  5. 5. ESD Is the Hidden Enemy There are innumerable ESD events occurring all the time that we cannot see or feel. . People Feel ESD at 2000 Volts!!!! Component damage – can occur with as little as 15 – 30 Volts!!!! Examples of Static Generation Typical Voltage Levels Examples of Static Generation Typical Voltage Levels Means of Generation 10-25% RH 65-90% RH Walking across carpet 35,000V 1,500V Means of Generation 10-25% RH 65-90% RH Walking across vinyl tile 12,000V 250V Walking across carpet 35,000V 1,500V Worker at bench 6,000V 100V Walking across vinyl tile 12,000V 250V Poly bag picked up from bench 20,000V 1,200V Worker at bench 6,000V 100V Chair with urethane foam 18,000V 1,500V Poly bag picked up from bench 20,000V 1,200V Chair with urethane foam 18,000V 1,500V
  6. 6. Typed of Materials that Charge Conductors Insulators .  Materials that easily transfer  Materials that hold an electric electric charge charge and can not easily  Can be used to transfer transfer the charge charge to earths ground  Can not be grounded to earth  Examples by common means •Metals  Examples •Water •Plastics •Carbon •Glass •People •Dry Air
  7. 7. Sources of ESD The following items are examples of materials that generate and hold electrostatic charge.  Vinyl binders  Paper, schematics, etc.  Equipment covers  Plastic work travelers  Plastic document  Plastic spray bottles holders/sheet protectors  Personal items TM  Post-It notes –Purses  Plastic pens –Sweaters/jackets  Bubble wrap –Insulated lunch totes –Combs/brushes  Plastic housings on –Lotion bottles equipment
  8. 8. What type of Materials are ESD Sensitive? ESDS – Electrostatic Discharge Sensitive Integrated Circuits (DIPs, QFP, BGA, SOT, etc.)  Crystals and oscillators  Printed Circuit Board Assemblies  When in doubt, treat it as ESDS!
  9. 9. Common Causes of ESD  Opening a common plastic bag  Removing adhesive tape from a roll or container  Walking across a floor and grabbing the door knob  Transporting computer boards or components around in their trays on non- ESD carts  Sliding circuit boards on a work bench
  10. 10. Types of ESD Damage CATASTROPHIC FAILURE  A device is exposed to ESD and it no longer works  The device circuitry is permanently damaged  Such failures may be caught when tested, before shipment LATENT FAILURE  A device is exposed to ESD and is partially damaged, yet it continues to work  The product may have a failure after the user Image of the ESD damage after removal of the capacitor metallization. places it in service Magnification is 10,500 times
  11. 11. Example of ESD Damage  Opticalphoto of a large Integrated Circuit which has experienced ESD damage to the pin noted by the arrow.
  12. 12. Example of ESD Damage  Higher magnification photo of pin noted by the arrow in the prior slide This taken at 400 times magnification on a 4″ X 5″ photo. The damage is noted as the “fuzz” at the end of the arrow.
  13. 13. Example of ESD Damage  Overlying glassivation has been removed and the surface decorated to show the ESD damage at 5,000 times magnification in this scanning electron micrograph.
  14. 14. Why is ESD Important? Electrostatic Discharge (ESD) can damage sensitive electronic devices, resulting in:  Higher manufacturing costs  Rework  Repair  Scrap  Lower production yields  Unhappy customers  Shorter product life  Reduce product reliability Estimates of actual cost of ESD damage to the electronics industry = $$$ Billions annually
  15. 15. How to control ESD? ESD Control Program  ESD Training  ESD Control Areas  Ground Conductors  Ionization  ESDS Component Handling and Storage
  16. 16. ESD Control Program The first step in ESD control is to train all personnel who may come in contact with static sensitive materials  Proper use of personal grounding equipment such as heel grounders or wrist straps  Personnel should understand ESD equipment test methods and documentation  Understanding of other ESD control methods such as ionization
  17. 17. ESD Control Program Any area where unprotected ESD sensitive parts and assemblies may be handled shall be designated an ESD Control Area, and must meet the following requirements;  The area is free from non-essential static generators, and the risk from process-essential static generators is minimized  All personnel must be grounded and grounding equipment must be tested daily  All movable carts, racks, etc. are grounded  The area is labeled as an ESD control area, and the boundaries are clearly marked
  18. 18. Create an ESD Control Area  Any area where unprotected ESDS parts and assemblies may be handled  ESD areas must be labeled with posted signs and their boundaries marked
  19. 19. ESD Control Program Cont. All Conductors within the EPA must be grounded  Personal Grounding: All personnel, including visitors  Work surfaces and flooring  All equipment in EPA
  20. 20. Personal Grounding Wrist Straps and Coil Cords  Wrist Straps ground personnel at workstations Heel Grounders  Ground mobile personnel in areas where there are ESD floors Smocks  Smock sleeves should be in contact with the skin, clothing underneath should not show
  21. 21. Personal Grounding All Personal Grounding Equipment Should be Tested or Monitored Daily  Wrist Strap and Footwear Testing Stations  ESD ground monitoring  Constant  Impedance OHM Metrics and Monroe Electronics Test and Measurement Products CM Series ESD Workstation Monitors
  22. 22. Equipment Grounding Work Stations and Tables  Must have static dissipative surfaces connected to the building ground source.  Must have wrist strap ground connections (2 recommended), preferably banana jack receptacles, connected in parallel to the bldg ground source  Should be cleaned daily with an antistatic cleaner
  23. 23. Equipment Grounding Shelving and Cabinets  Must provide a grounded surface unless the parts remain fully enclosed within shielding-type packaging Storage Bins  All parts bins and containers must be static dissipative or antistatic  Whenever practical, sensitive parts should remain in the original container until assembled
  24. 24. Ionization Many times, equipment or objects(insulators) are unable to be grounded in which case air ionizers should be used. What is Ionization? Air Ionizers use a process called “neutralization” to remove static charge from insulators that cannot be grounded.  Ionizers produce positively and negatively charged ions and floods ESD area with Ions.  Ions are charged particles that are present in the air, and as opposites attract, charges will be neutralized over time.
  25. 25. Types of Air Ionizers  Bench Top  Ionizing Nozzles  Air Guns  Overhead Ionizers
  26. 26. ESDS Component Handling and Storage To move ESDS parts or assemblies inside an ESD control area, use one of the following;  Static dissipative containers  Static shielding containers  Conductive containers or board carriers  Ground movable racks Surface Mount Devices SMD Boxes
  27. 27. ESD Basics Review Things to remember about an ESD protection plan.  Only allow trained or escorted people in EPA  Ground all conductors including people at ESD workstation  Test wrist straps at least daily, or use continuous monitors  Test ESD footwear at least daily, if used  Visually check all grounding cords  Keep wristband snug, foot grounder grounding tab in shoe, and ESD smocks buttoned  Ionizers are maintained and air flow directed at ESDS items  Use shielded packaging for shipping or storing ESD sensitive items outside the ESD Protected Area  Handle unpacked ESDS items only when grounded
  28. 28. About Transforming Technologies Transforming Technologies is a leader in static protection, offering a wide range of unique and exceptional ESD products to prevent, eliminate and monitor electrostatic charges.  Constant Monitors  ESD Apparel: ESD Hot Glove, ESD Jackets  Ionization: Alpha, Bench Top, Overhead, Gun, Nozzles  Personal Grounding: Coil Cords, Wrist Straps, Footwear, Grounding Cords  SMD Boxes  Surface Protection: Rubber, Vinyl, PVC  Test and Measurement Equipment

The Prevention and Control of Electrostatic Discharge (ESD) (AN-40-005) An Introduction to ESD We experience occurrences of static electricity everyday. For example, walking along a carpeted floor in a heated room during winter generates sufficient static electricity to give us a rather shocking experience when we touch the door knob. While this sudden discharge of static electricity does not result in any harm to the human body, it can be very damaging to electronic devices which are sensitive to electrostatic discharge (ESD). It is possible for electronic devices to be damaged by ESD that is imperceptible to the human body. This document is intended to shed some light on the sources of ESD and provides guidelines on the prevention and control of ESD. Object or process Material or activity _ Work surfaces Waxed, painted or plastic surfaces. Floors Waxed, common vinyl tiles, sealed concrete Clothes Common smocks, non-conductive shoes, synthetic materials (e.g. nylon) Chairs Vinyl, fiber-glass, finished wood Packaging Common plastic bags, foam, trays, tote boxes Assembly area Spray cleaners, heat guns, blowers, plastic tools (e.g. solder suckers, brushes) cathode ray tubes. What are the common sources of static electricity? The following table shows a sample list of sources of static electricity. What are typical examples of static charge inducing situations? Does humidity have any effect on the induced static charge? The following table shows some typical situations. Please note that humidity has a significant effect on the induced charge. It is not recommended to have relative humidity (RH) that is too low, say, below 30%. ESD control becomes especially challenging at low RH levels. A relative humidity between 40% to 60% is recommended for the typical assembly area. Means of static generation RH 10-20% RH 65-90% Walking across a carpet 35,000 V 1,500 V Walking on a vinyl tile floor 12,000 V 250 V Vinyl envelopes for work instructions 7,000 V 600 V Worker at bench 6,000 V 100 V