6/6/2014 nasa workmanship standards 1 esd stress test models josé d. sancho

04/10/23NASA Workmanship Standards1

ESD Stress Test ModelsESD Stress Test Models

José D. Sancho


Introduction Introduction

General CommentsWhat 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


AgendaAgenda

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


Overview 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.

CDMTLP

MM

HBM

ESD Models: (differences & interrelation)


The Human Body Model (HBM)The Human Body Model (HBM)

Simulates an Electrostatic Discharge from the human body to a device (e.g. electronic component).

Courtesy of Botron Co.

•Most commonly used model• Best understood by operators• Best controlled by Equipment and Training


HBM Test CircuitHBM Test Circuit

Basic HBM Test Circuit

HV Supply

100 Meg SW1

SW2

1.5 K

10 K-10 Meg

100 pf

DUT IPS

IPR 500 Ω

Courtesy of ESDA


HBM WaveformsHBM Waveforms

Stress Waveform Used for HBM ESD Testing

ANSI/ESD STM5.1-2001



Current Waveform through a shorting wire

Older waveform.


Typical HBM Typical HBM Generated FailuresGenerated Failures

2000X100XCourtesy of JPL Scott M. Hull NASA/GSFC


The Machine Model (MM)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


Original MM Circuit & WaveformOriginal MM Circuit & Waveform

HV Supply

SW1

SW2

100 Meg

10 K-10 Meg

200 pf

DUT

500 nH


ESDA Machine Model CircuitESDA Machine Model Circuit

HV Supply

SW1

SW2

100 Meg

10 K-10 Meg200 pf

DUT500 ΩShort

IpS IpR


ESDA MM Test WaveformsESDA MM Test WaveformsANSI/ESD STM5.2-1999ANSI/ESD STM5.2-1999

400 v discharge through a shorting wire 400 v discharge through a 500 Ω resistor


Typical MM ESD Stress FailureTypical MM ESD Stress Failure

Scott M. Hull NASA/GSFC


The Charge Device Model (CDM)The Charge Device Model (CDM)Simulates Electrostatic Charge transfer from

a Device.Two sub-models are used R-CDM & SDMTest 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


Charge Device Model CircuitsCharge Device Model Circuits

Rc

Rd1 Rd2Rdn

Ld1Ld2 Ldn

Sw1

Rd

Ld

Cd

Sw1

Rc

Device with One Point Discharge

Device with Multiple Discharge Paths

Cd1Cd2 Cdn

Rc = Resistance to Ground. Rd, Ld, Cd = Resistance, Inductance & CapacitanceIn the Discharge Path.

DUTDUT


ESDA CDM Test WaveformESDA CDM Test Waveform

ANSI/ESD STM5.3.1-1999

Waveform for the verification Modules using a 3.5 GHz BW


Typical CDM generated failuresTypical CDM generated failures

4600x

8600x

Courtesy of JPLCourtesy of JPLCourtesy of JPLCourtesy of JPL


Typical CDM Generated FailureTypical CDM Generated FailureCourtesy of Frederick Felt GSFC Part Analysis Lab.

ESD event (~1 KV) shown at arrow after parallel Polishing


Models ComparisonsModels ComparisonsESD Models ZD RC CD (pf) LD (μH) ΕS (μJ) 5τ (ηs) Pave (W) IPS (A)

Vc = 200 V Typ. # Req # Req # Typ # ½CV2 5ReC Ε/τeff V/Re

HBM 0 1500 100 0 2 750 3 0.13

MM 55 2 200 5.0E-07 4 160 25 3.5

CDM 42 25 15 1.0E-08 0.3 5 30 3

ESD Models ZD RC CD LD ΕS in μJ 5τ in ηs Pave (W) IPS

Vc = 1000 V Typ.# Req # Req # Typ # ½CV2 5ReC Ε/τeff V/Re

HBM 0 1500 100 0 50 750 ~67 0.67

MM 55 2 200 5.0E-07 100 160 625 17.5

CDM 42 25 15 1.0E-08 7.5 5 >750 15

Courtesy of ESDA


Transmission Line Pulse (TLP)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.


TLP Design MethodologiesTLP Design Methodologies

Current SourceTime Domain ReflectometerTime Domain TransmissionTime Domain Reflection and Transmission


Current Source TLPCurrent Source TLP

ANSI/ESD SP5.5.1-2004


Time Domain Reflectometer TLPTime Domain Reflectometer TLP



Time Domain Transmission TLPTime Domain Transmission TLP



TDR&T TLPTDR&T TLP



SummarySummary

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: jsancho.1@[email protected]


Where to Get More InformationWhere to Get More Information

WEB searches under “ESD Models”ESDA publicationsConsulting services provide Advice on

tough ESD problems and Solutions.


ReferencesReferences1. ANSI/ESD STM5.1-2001 ESD Sensitivity Testing (HBM)2. ANSI/ESD STM5.2-1999 ESD Sensitivity Testing (MM)3. ANSI/ESD STM5.3.1-1999 ESD Sensitivity Testing (CDM)4. ANSI/ESD SP5.2.2-2004 ESD Sensitivity Testing (SDM)5. ANSI/ESD SP5.5.1-2004 ESD Sensitivity Testing (TPL)6. Scott M. Hull, “ESD Failures in Thin-Film Resistors”

NASA/Goddard Space Flight Center 7. http://qa.jpl.nasa.gov/esd/8. http://esdsystems.com/whitepapers/9. http://www.semiconfareast.com10. http://www.ce-mag.com/archive/01/09/henry.html11. http://www.ce-mag.com/ce-mag.com/archive/

01/03/0103CE_046.html

6/6/2014 nasa workmanship standards 1 esd stress test models josé d. sancho

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