1. ESD Stress Test Models José D. Sancho NASA Workmanship Standards
4/1/2017

2. Introduction General Comments What is an ESD Sensitivity Level?
How is it obtained?
Why is it important to the user?
Why different test models?
How we can reduce ESD related failures
NASA Workmanship Standards
4/1/2017

3. Agenda The human body model (HBM) The machine model (MM)
The charge device model (CDM)
Robotic (Real) CDM (R-CDM)
Socketed CDM (SDM)
Damage differences between models
Transmission Line Pulse (TLP) stress testing
Reasons for CDM/TLP current emphasis
Questions
NASA Workmanship Standards
4/1/2017

4. (differences & interrelation)
Overview
ESD standard test models define the ESD sensitivity level of electronic parts.
Their Significance to the different sensitivity levels used in industry.
FA recognition of the model responsible for an ESD failure event.
HBM MM
ESD Models:
(differences & interrelation)
TLP
CDM
NASA Workmanship Standards
4/1/2017

5. The Human Body Model (HBM)
Simulates an Electrostatic Discharge from the human body to a device (e.g. electronic component).
Most commonly used model
Best understood by operators
Best controlled by Equipment and Training
Courtesy of Botron Co.
NASA Workmanship Standards
4/1/2017

6. HBM Test Circuit Basic HBM Test Circuit Courtesy of ESDA
100 Meg
SW1
1.5 K
SW2
DUT
IPS
IPR
HV Supply
500 Ω
100 pf
10 K-10 Meg
Courtesy of ESDA
Basic HBM Test Circuit
NASA Workmanship Standards
4/1/2017

7. HBM Waveforms Stress Waveform Used for HBM ESD Testing Older waveform.
ANSI/ESD STM
Current Waveform through a shorting wire
ANSI/ESD STM
ANSI/ESD STM
Stress Waveform Used for HBM ESD Testing
NASA Workmanship Standards
4/1/2017

8. Typical HBM Generated Failures
100X
2000X
Scott M. Hull NASA/GSFC
Courtesy of JPL
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4/1/2017

9. The Machine Model (MM) Originated in Japan
Discharge from Equipment or Small Tools to a Device
Simulates some ESD events in Automatic Equipment
Repetitive, faster and more severe than the HBM
Mostly used in the design of Automatic Handling Equipment and ESD-safe tools
NASA Workmanship Standards
4/1/2017

10. Original MM Circuit & Waveform
100 Meg
500 nH
SW1
SW2
DUT
HV Supply
200 pf
10 K-10 Meg
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4/1/2017

11. ESDA Machine Model Circuit
HV Supply
SW1
SW2
100 Meg
10 K-10 Meg
200 pf
DUT
500 Ω
Short
IpS
IpR
NASA Workmanship Standards
4/1/2017

12. ESDA MM Test Waveforms ANSI/ESD STM5.2-1999 ANSI/ESD STM5.2-1999
400 v discharge through a shorting wire
400 v discharge through a 500 Ω resistor
NASA Workmanship Standards
4/1/2017

13. Typical MM ESD Stress Failure
Scott M. Hull NASA/GSFC
NASA Workmanship Standards
4/1/2017

14. The Charge Device Model (CDM)
Simulates Electrostatic Charge transfer from a Device.
Two sub-models are used R-CDM & SDM
Test repeatability between Test-Sets has been a problem.
Per ESDA Statistics, 90% of all field failures are caused by CDM ESD events.
Failures are typically at the core of the Device
NASA Workmanship Standards
4/1/2017

15. Charge Device Model Circuits
Device with One Point Discharge
Device with Multiple Discharge Paths
Sw1
DUT Rc
Rd1
Rd2
Rdn
Ld1
Ld2
Ldn
Sw1
DUT Rd Ld Rc Cd
Cd1
Cd2
Cdn
Rc = Resistance to Ground. Rd, Ld, Cd = Resistance, Inductance & Capacitance
In the Discharge Path.
NASA Workmanship Standards
4/1/2017

16. Waveform for the verification Modules using a 3.5 GHz BW
ESDA CDM Test Waveform
ANSI/ESD STM
Waveform for the verification Modules using a 3.5 GHz BW
NASA Workmanship Standards
4/1/2017

17. Typical CDM generated failures
4600x
8600x
Courtesy of JPL
Courtesy of JPL
NASA Workmanship Standards
4/1/2017

18. Typical CDM Generated Failure
Courtesy of Frederick Felt GSFC Part Analysis Lab.
ESD event (~1 KV) shown at arrow after parallel Polishing
NASA Workmanship Standards
4/1/2017

19. Models Comparisons Courtesy of ESDA ESD Models ZD RC CD (pf) LD (μH)
ΕS (μJ)
5τ (ηs)
Pave (W)
IPS (A)
Vc = 200 V
Typ. #
Req #
Typ #
½CV2
5ReC
Ε/τeff
V/Re
HBM
1500
100 2
750 3
0.13 MM 55
200
5.0E-07 4
160 25
3.5
CDM 42 15
1.0E-08
0.3 5 30 CD LD
ΕS in μJ
5τ in ηs
IPS
Vc = 1000 V
Typ.#
Req #
Typ # 50
~67
0.67
625
17.5
7.5
>750
Courtesy of ESDA
NASA Workmanship Standards
4/1/2017

20. Transmission Line Pulse (TLP)
Used By IC Designers since 1985 to evaluate ESD protection schemes.
Simulates HBM with very short pulses.
Allows non-destructive & latch-up issues testing.
Provides better results on a controlled simulation of the SDM.
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4/1/2017

21. TLP Design Methodologies
Current Source
Time Domain Reflectometer
Time Domain Transmission
Time Domain Reflection and Transmission
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4/1/2017

22. Current Source TLP ANSI/ESD SP5.5.1-2004 NASA Workmanship Standards
4/1/2017

23. Time Domain Reflectometer TLP
ANSI/ESD SP
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4/1/2017

24. Time Domain Transmission TLP
ANSI/ESD SP
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4/1/2017

25. TDR&T TLP
ANSI/ESD SP
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4/1/2017

26. Summary Models establish Benchmarks for ESD Sensitivity.
Different Models are used under different environments.
Models provide help to prevent and analyze ESD Failures
Please send feedback to:
NASA Workmanship Standards
4/1/2017

27. Where to Get More Information
WEB searches under “ESD Models”
ESDA publications
Consulting services provide Advice on tough ESD problems and Solutions.
NASA Workmanship Standards
4/1/2017

28. References ANSI/ESD STM5.1-2001 ESD Sensitivity Testing (HBM)
ANSI/ESD STM ESD Sensitivity Testing (MM)
ANSI/ESD STM ESD Sensitivity Testing (CDM)
ANSI/ESD SP ESD Sensitivity Testing (SDM)
ANSI/ESD SP ESD Sensitivity Testing (TPL)
Scott M. Hull, “ESD Failures in Thin-Film Resistors” NASA/Goddard Space Flight Center
NASA Workmanship Standards
4/1/2017