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SEMI E43-0301 © SEMI 1995 , 2001 13 + + + + + + + + + + + + + Grounded Sur fa ce Field Lines Terminate on Ground and Do Not Accurately Represent Charge on the Sur fa ce Charged Sur fa ce Field Lines Due to St atic Charg …

SEMI E43-0301 © SEMI 1995, 2001 12

RELATED INFORMATION 2

NOTES ON TEST METHODS

NOTE: This related information is not an official part of this standard. However, it contains relevant information for using the

standard in situations commonly encountered with semiconductor manufacturing facilities and equipment. Determination of the

suitability of the material is solely the responsibility of the user.

R2-1 Prior handling and environmental conditions will

significantly impact the field strength to be measured.

Below are a number of these considerations:

• The presence of nearby grounded surface or object

will tend to reduce the measured field strength.

This phenomena is known as field suppression and

is illustrated in Figure R2-1.

• Ionization of the surrounding air will tend to

reduce the measured field strength by neutralizing

the static charge on the surface of the object.

• Rubbing or contacting the surface being measured

with another object or surface will tend to increase

the measured field strength depending upon the

tendency of the two materials in question to

tribocharge.

• Increasing humidity will tend to reduce the field

strength to be measured because it in turn will

reduce the magnitude of the charge generated on

objects and, over time, assist in the neutralization

of charge on objects.

• Projections and sharp protrusions on the object

being measured, or nearby objects, will increase

the field strength.

• Insulating objects may have very irregular charge

distributions.

• As a result of these considerations, a static

measurement or survey made using this standard is

only useful if these factors are taken into account in

a realistic manner. For example:

• If a surface is only used in a humidity or

temperature controlled environment, field

strength measurements made under these

conditions are the main ones of interest.

Measurements made at different humidities

may be irrelevant.

• An object may present close to zero field in an

ionized environment, yet when contacted by

another object may become highly charged.

This charge may persist for a period of seconds

or minutes while it is neutralized by the ionized

environment. The time required to return the

object to its original state may be a parameter

of interest.

• An object resting on a grounded metal surface

may have very low external field strength. If

the object is picked up and measured the field

may be much higher.

• Objects of irregular shape and size will give

highly variable readings, depending on the

position of the sensor relative to the object.

• Dielectric objects may give highly variable

readings, depending upon the position of the

sensor relative to the charge distribution on the

object.

• The simple act of handling an object while

performing a static survey can change the

charge on the object. The best results will

derive from making sure that objects and

surfaces are treated and handled within the

bounds of their actual use.

• During equipment verification, maintaining

constant/steady voltage is important. If the plate is

initially charged and allowed to float, its voltage

will change as the meter is moved close to it.

SEMI E43-0301 © SEMI 1995, 200113

+ + + + + + + + + + + + +

Grounded Surface

Field Lines Terminate on Ground

and Do Not Accurately

Represent Charge on the Surface

Charged Surface

Field Lines Due to Static Charge

+ + + + + + + + + + + + + + + + +

Figure R2-1

Field Suppression

SEMI E43-0301 © SEMI 1995, 2001 14

RELATED INFORMATION 3

ESD DAMAGE SIMULATORS

NOTE: This related information is not an official part of this standard. However, it contains relevant information for using the

standard in situations commonly encountered with semiconductor manufacturing facilities and equipment. Determination of the

suitability of the material is solely the responsibility of the user.

R3-1 ESD Damage Simulators

R3-1.1 ESD Simulators are used to replicate ESD

events. Common types used to characterize

semiconductor devices and equipment include:

• Component Level HBM ESD Simulator.

• Component Level MM ESD Simulator.

• Component Level CDM ESD Simulator

• System Level HBM/metal ESD Simulator

R3-1.2 The component level HBM ESD Simulator

represents the parameters agreed upon for a standard,

which represents the discharge from a typical human

body. These parameters are 1500 ohms and 100 pF for

the representative resistance and capacitance

respectively of the human body.

R3-1.3 The component level MM ESD Simulator

represents the parameters agreed upon for a standard,

which represents the discharge from a charged metallic

arm of a machine (automatic handler etc). These

parameters are 200 pF and zero resistance for the

representative capacitance and DC resistance

respectively of the machine. We note here that the

resulting waveform is dependent on the impedance of

the circuity.

R3-1.4 The component level CDM ESD Simulator

represents the parameters agreed upon for a standard,

which represents the discharge from a charged device.

These parameters are defined by the resulting

waveform and depend almost exclusively on the

capacitance, resistance and inductance of each device

relative to ground. These parameters must not be

confused with the equipment parameters, which affects

the resulting waveform.

R3-1.5 The system level HBM/metal ESD Simulator

represents the parameters agreed upon for a standard,

which represents the discharge from a human holding a

metallic instrument. These parameters are the lower

resistance 350 ohms and 150 pF for the representative

resistance and capacitance respectively of the human

holding a metallic instrument. Note here that the

waveform is greatly affected by the equipment

parasitics.

R3.1.6 The above component level ESD simulators

have also been used in simulating ESD damage to

tooling, such as reticles and photomasks. This

simulation is left to user discretion.

R3-2 Summary of procedures

R3-2.1 HBM ESD Simulator-component level — The

procedure for using this simulator to stress test devices

or wafers is based upon the standard requirements.

ANSI and the ESD Association approved the HBM

standard, ESD STM5.1, which contains a specific

device pin combination sequence for stress testing.

This test procedure is generally referred to as a Pin to

Ground test since one pin is always grounded while the

selected second pin is stressed. Calibration before use

requires added equipment components like a current

probe, high bandpass cable, a short wire, a 500 ohm

resistor and a very high band width waveform

recorder/digitizer.

R3-2.2 MM ESD Simulator-component level — The

procedure for using this simulator to stress test devices

or wafers is based upon the standard requirements. The

ESD S5.2 approved MM standard specifies a specific

device pin combination sequence for stress testing.

This test procedure is also generally referred to as a Pin

to Ground test since one pin is always grounded while

the selected second pin is stressed. This procedure is

exactly the same as for HBM. Calibration before use

requires added equipment components like a current

probe, high bandpass cable, short wire, a 500 ohm

resistor and a very high band width waveform

recorder/digitizer.

R3-2.3 CDM ESD Simulator-component level — The

procedure for using this simulator to stress test devices

or wafers is based upon the standard requirements. The

ESD STM 5.3.1 approved CDM standard does not use a

pin combination procedure. Here the device sits on a

charge plate (CP) “dead-bug” style (package on CP and

leads/pins vertical) and each pin is discharged

successively after each charge to the device package.

This procedure is different from that of HBM and MM.

Calibration before use requires added equipment

components like a capacitance/inductance calibrator,

high bandpass cable and a very high band width

waveform recorder/digitizer.

R3-2.4 HBM-metal Simulator- system level — The

procedure for using this hand-held simulator for testing

systems (ATE testers, Automatic handlers, computers,

printers, ESD Simulators etc) is based upon the