ESD 02- Grounding, TR53 and compliance plan (相容模式)
ESD 02- Grounding, TR53 and compliance plan (相容模式)
ESD 02- Grounding, TR53 and compliance plan (相容模式)
TUTOR: SL HO
Fundamental principles
Fundamental principles in electrostatic-protected area (EPA) : Electrically interconnecting all conductive and dissipative itemsthat is, bonding them; and attaching them to ground; an area free of differences in electrical potential - EPA
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Choosing the Grounding System AC Equipment Ground Auxiliary Ground Equipotential Bonding
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AC Equipment Ground
Within EPA, the preferred ground is the AC equipment ground the third-wire terminal electrically bonds the AC equipment ground to the ground bus at the main service equipment panel of the facility
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Auxiliary Ground
For some purposes only: - to keep away any ESD spikes or electromagnetic-interference signals from electrical equipment that is not attached to that system in an EPA
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Auxiliary Ground
RISK: the difference in potential that could exist between different grounding systems (AC grounding and the Auxiliary grounding) SO: auxiliary ground and ac equipment ground need to be bonded together whenever possible IF both grounding systems are present, resistance between AC and Auxiliary ground shall be < 25 ohms.
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Equipotential Bonding
appropriate for remote or field operations where equipment is being serviced and a properly set up EPA is not available
Electrically interconnecting All things in the area everything within the system will be at some shared potential (potential vs Ground may be elevated). No difference in potential within the handling system, no discharge is possible ESD-susceptible items within the system can be safely handled
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Common-point ground
Common point ground point to point < than 1ohm
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Important notes:
Metal bench tops (stainless steel worksurfaces) MUST be connected directly to AC equipment ground with no added resistance. Avoidance of CDM issue. Wires used within the EPA shall be of sufficient strength, not to be inadvertently broken or disconnected. Resistance of the conductor from the groundable point ground of any ESD technical element (worksurface, floor, chair, wrist strap) to common point ground shall not be greater than 1 ohm.
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Important notes: Resistance of conductor from common point ground to the AC equipment ground shall not be greater than 1 ohm
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Worksurfaces
Test Equipment An integrated checker or meter, whether it is a single meter or a collection of instruments that are capable of measuring at least 1.0 x 1010 ohms with a test voltage of 10 and 100 volts ( 10%) DC open circuit. One electrode Two test leads of sufficient length DC Ohmmeter
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Wrist Straps
Test Equipment Integrated checker or meter, whether it is a single meter or a collection of instruments that are capable of measuring from 5.0 x 104 ohms to at least 1.0 x 1010 ohms with a test voltage between 7 and 30 volts DC open circuit. Some integrated checkers require manual selection to wrist strap resistance test ranges. Hand-held electrode One test lead of sufficient length
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Footwear
Test Equipment Integrated checker or meter, whether it is a single meter or a collection of instruments that are capable of measuring from 5.0 x 104 ohms to at least 1.0 x 1010 ohms with a test voltage between 7 and 30 volts DC open circuit. Some integrated checkers require manual selection to Footwear resistance test ranges. Hand-held electrode Foot electrode Two test leads of sufficient length
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Flooring
Test Equipment Integrated checker or meter, whether it is a single meter or a collection of instruments that are capable of measuring at least 1.0 x 1010 ohms with a test voltage of 10 and 100 volts ( 10%) DC open circuit. One electrode Two test leads of sufficient length
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Seating
Test Equipment: An integrated checker or meter, whether it is a single meter or a collection of instruments that are capable of measuring at least 1.0 x 1010 ohms with a test voltage of 10 and 100 volts ( 10%) DC open circuit. One electrode Two test leads of sufficient length
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Field Meter Detects ESD Potential from any Source Measure ionizer performance
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Surface Resistance Meter: Measures point-to-point resistance (RTT) & point-to-ground resistance (RTG).
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Compliance Verification Plan establish Compliance Verification Plan measurement limits and the frequency shall document the test methods and equipment used for process monitoring and measurements Compliance verification records shall be established and maintained
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Limits
Rs < 1.0x107
Test Procedure
ESD Association publication TR53: Wrist strap section
Test Frequency
Daily (before use)
Checked By
Operator
Footwear
Operator
Flooring
Work surface
Rs refers to system resistance including person, the wrist band and the grounding cord or ESD footwear Rg refers to resistance to ground
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End of section
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