1. Electro Static Discharge Control
A. COURSE WELCOME
Introduction of instructor
1. Background
2. Teaching Experience
3. Qualifications
B. COURSE REQUIREMENTS
1.Course length
2.Exam
Naval Surface Warfare Center
Crane Division

2. WORK INSTRUCTION FOR ELECTROSTATIC DISCHARGE PROTECTIONWI
WORK INSTRUCTION
FOR
ELECTROSTATIC DISCHARGE PROTECTION

3. History of Static Electricity
First observed: Lightening in a storm observed since the dawn of man
First recorded experiments: 600 b.c.
Studied extensively: 16th & 17th centuries
First Electronic Failures: 1940s

4. Static Problems in Industry

5. Reasons for Disbelief
Most ESD damage occurs below human sensitivity level ( < 3500 V )
Many subtle damage paths
Assorted parts affected: No trend
Damage often invisible under microscope
Sophisticated analysis necessary

6. Problem Estimates Dick Moss - Hewlett Packard All component failures:
5 to 25% ESD caused
Burt Unger - Bell Labs
Dead on arrivals:
50% ESD caused
Lou DeChario - Bell Labs
Early life operating failures:
> 50% ESD caused

7. Type Defects Catastrophic failure - device doesn’t work Latent defect
- device works but is degraded
- most costly defect
- possible weapon systems failure

8. $ $ $ Estimates
In manufacturing environment estimating is an easy process because of increased yields.
In repair facilities estimates are difficult to evaluate.
But in both environments the savings are in the billions of dollars per year

9. Motionless electricity electrical charges at rest
Static Electricity
Motionless electricity or
electrical charges at rest

10. Factors Affecting Static Charge Generation
Intimacy of contact
Speed of separation
Conductivity of materials
Triboelectric series

11. CHARGE GENERATION
INTIMACY OF CONTACT +
SPEED OF SEPARATION

12. CONDUCTIVITY OF MATERIALS
NON-CONDUCTOR
CONDUCTOR
NON-CONDUCTOR
CONDUCTOR
GROUND

13. Electro Static Charges
To feel it ,500 Volts or more required
To hear it -- 4,500 Volts or more required
To see it ,000 Volts or more required
Static cling - 7,500 Volts or more required

14. Electrostatic Field
Lines of force present around a charged body

15. Typical Prime Charge Sources

16. PACKAGING AND HANDLING
Common plastic bags, wraps, envelopes
Common bubble pack, foam
Common plastic trays, plastic totes, boxes, vials, parts bins, tape

17. ASSEMBLY, CLEANING, TEST & REPAIR AREAS
Spray cleaners
Common plastic solder suckers
Soldering irons with ungrounded tips
Brushes (synthetic bristles)
Cleaning or drying by fluid evaporation
Temperature chambers
Cryogenic sprays
Heat guns and blowers
Sandblasting
Electrostatic copiers

18. CLOTHES Common clean room smocks Common synthetic personnel garments
Nonconductive shoes
Virgin cotton
at very low humidities

19. WORK SURFACES Waxed, painted, or varnished surfaces
Common vinyl or plastics

20. CHAIRS
Finished wood
Vinyl
Fiberglass

21. FLOORS Sealed concrete Waxed, finished wood
Common vinyl tile or sheeting

22. TRIBOELECTRIC SERIES

23. Typical Charge Levels Personnel - 1.5 KV to 20 KV
Plastic materials - 2 KV to 35 KV

24. Typical Electrostatic Voltages

25. WHAT WE DON'T FEEL:
ESD < 3,500 Volts
(But the circuit cards do)

26. Static Susceptibility of Semiconductor Devices

27. DANGER
Some devices may be damaged with voltages as low as Volts

28. Preventing Electrostatic Damage

29. Preventing Static Charge Damage
Eliminate the charges from ESD Safe Areas
Neutralize the charges within ESD Safe Areas
Provide a conductive path to prevent static charge build up
Effective on conductive surfaces only
Little or no effect on nonconductive surfaces
Provide a conductive barrier between sensitive devices and charged nonconductive surfaces
Example: Wrapping a sensitive device in a conductive antistatic package

30. The 3 Commandments of ESD
All electronic devices are considered ESD sensitive
Never expose electronic devices to electrostatic fields
Never touch (or discharge to) the leads or terminals of an electronic device

31. Protection Requirements
ESD safe area for handling electronic devices
Proper packaging and storage of electronic devices
Proper training of all personnel including visitors

32. ESD Safe Area A grounded static dissipative work surface
Personnel wrist strap and cord connected to ground
Sign indicating “ESD safe area”

34. Working in ESD Safe Area
Check wrist strap & cord
2 foot rule
No food, no drink
Only ESD trained
Work directly on ESD mat
Visitors need to be grounded
Clean
Electronic Devices always protected

35. Packaging and Storage
Understanding ESD packaging protection and basic storage principle
Know your ESD packaging materials

36. The Faraday Cage

37. Packaging Material Common plastic material Anti static material
Nickel shielded material
Conductive material
Tote Boxes
Fast Packs

38. Preventing Static Charge Damage
Eliminate the charges from ESD Safe Areas
Neutralize the charges within ESD Safe Areas
Provide a conductive path to prevent static charge build up
Effective on conductive surfaces only
Little or no effect on nonconductive surfaces
Provide a conductive barrier between sensitive devices and charged nonconductive surfaces
Example: Wrapping a sensitive device in a conductive antistatic package

40. FEDLOG Enter Cage Code 20999 Enter P/N 4270* = Circular caps or
Enter P/N 4272* = D Type caps
Search

41. Will not protect against ESD
For Packaging only!!!

47. MIL-B-81705 TY3 8105-01-386-3863 ESD BARRIER 4 X 4 ZIPLOCK
ESD BARRIER / BUBBLE 6 X 10 ZIPLOCK
ESD BARRIER / BUBBLE 8 X 10 ZIPLOCK
ESD BARRIER / BUBBLE 10 X 12 ZIPLOCK

49. 3M Model 724 Constant Monitor System

51. ALL=SPEC

57. NOT PERMITTED IN STATIC CONTROL AREAS
Styrofoam / Plastic Cups
Polyethylene Envelopes, Sheets, Bags etc..
Common Bubble-Pack and Packaging Foam
Scotch Tape
Rubber Pads
Plastic Tote Boxes
Unnecessary Insulating Materials in General

58. Safety Precautions
All antistatic work surfaces must be connected to a common ground through a resistance of :
1 Meg ohm minimum
2 Meg ohm maximum
Never connect personnel to common ground
Power tools must be transformer or D.C. isolated
No plastic items on the work surface

59. ARE THERE ANY ? ? ?
QUESTIONS ? ?

67. ARE THERE ANY ? ? ?
QUESTIONS ? ?