How Electro-Static Charges Cause Damage; Table 11-1: Static Generation Voltages For Typical Activities; Table 11-2: Sensitivity Of Electronic Devices To Damage By Esd - Teledyne T700 Operation Manual

A Primer on Electro-Static Discharge

11.2. HOW ELECTRO-STATIC CHARGES CAUSE DAMAGE

Table 11-2: Sensitivity of Electronic Devices to Damage by ESD

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workbench, using a plastic handled screwdriver or even the constant jostling of
TM
Styrofoam pellets during shipment can also build hefty static charges

Table 11-1: Static Generation Voltages for Typical Activities

MEANS OF GENERATION
Walking across nylon carpet
Walking across vinyl tile
Worker at bench
Poly bag picked up from bench
Moving around in a chair padded
with urethane foam
Damage to components occurs when these static charges come into contact with an
electronic device. Current flows as the charge moves along the conductive circuitry of
the device and the typically very high voltage levels of the charge overheat the delicate
traces of the integrated circuits, melting them or even vaporizing parts of them. When
examined by microscope the damage caused by electro-static discharge looks a lot like
tiny bomb craters littered across the landscape of the component's circuitry.
A quick comparison of the values in Table 11-1 with the those shown in the Table 11-2,
listing device susceptibility levels, shows why Semiconductor Reliability News estimates
that approximately 60% of device failures are the result of damage due to electro-static
discharge.
DAMAGE SUSCEPTIBILITY VOLTAGE
DEVICE
MOSFET 10
VMOS 30
NMOS 60
GaAsFET 60
EPROM 100
JFET 140
SAW 150
Op-AMP 190
CMOS 200
Schottky Diodes 300
Film Resistors 300
This Film Resistors 300
ECL 500
SCR 500
Schottky TTL 500
Potentially damaging electro-static discharges can occur:
Teledyne API – Model T700 Dynamic Dilution Calibrator
65-90% RH
1,500V
250V
100V
1,200V
1,500V
RANGE
DAMAGE BEGINS CATASTROPHIC
OCCURRING AT DAMAGE AT
100
1800
100
2000
100
7000
500
2500
3000
2500
3000
7000
500
1000
2500
10-25% RH
35,000V
12,000V
6,000V
20,000V
18,000V
06873B DCN6388