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April 2, 2008 Cyrous Rostamzadeh 1 “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh

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Page 1: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 1

“ESD Phenomena”ESD Mitigation Techniques

Cyrous Rostamzadeh

Page 2: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 2

Opening Question:

“It has Failed, Why?”

Page 3: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 3

Engineers get involved into System Level ESD through questions like……How to Fix an ESD problem on a DUT?

Page 4: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 4

Which Design Choices will preventESD problems? Or...

How do I optimize an IC design for the

Best System level ESD Performance?

Page 5: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 5

Is there a Correlation between

System level and IC level ESD?

To help to answer such questionsWe need to understand the fundamentals of ESD.

Page 6: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 6

Immediate Concern:Semiconductor Devices Fail when Exposed to ESD.

Why should We care about ESD?

Page 7: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 7

It is one of the most importantReliability problems in the“Integrated Circuit” Industry.

~ 50% of all “Field Failures”are due to ESD. It cannot be ignored.

Page 8: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 8

Requires “Knowledge”, and “Right Tools” to

Resolve ESD Problems.

SolutionSolution

Page 9: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 9

There is a purpose for every tool….Can I use soldering iron in place of screw driver? May be someone does! We should not!

ToolsTools……

Page 10: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 10

Knowledge is the key tool.Instrumentation is necessary.Critical Measurement is essential.

Knowledge, ToolsKnowledge, Tools,,……

Page 11: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 11

Microelectronic industry has led to an interest in ESD.Last 35 years, with the growth of Semiconductor industry, ESD has become a discipline of significant interest.

Page 12: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 12

In 1970’s as a result of concerns in the Cold War, EMP (Electromagnetic Pulses)

Excellent Physical Models were produced to understand the ESD Robustness of Electrical Components.

Page 13: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 13

In the 1980’s with the growth of Semiconductor Fabrication andthe Semiconductor Industry, ESD remained an issue as:Human handling, tooling, shipping and garments, influenced the reliability of Semiconductor Components.

Page 14: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 14

In 1990’s, tremendous growth in ESD understanding, as new fields and new issues continued to emerge...Transition from µ-Electronics to Nanostructures, Semiconductors, Magnetic Recording Devices, µ-Machines, MEM’s… Huge concern with ESD

Page 15: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 15

2000 - 2008, huge growth in ESD understanding, as new fields and new issues continue to emerge...Further transition in Nanostructures, High K Dielectric µ−processors, High Density FPGA, DSP…Mobile Phones, Portable Electronics….

Page 16: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 16

ESD means different things to different people

Page 17: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 17

For System User it means presence

or absence of Spark

ESD means different things to different people

Page 18: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 18

For Manufacture Engineer, it means wrist strap, ground mat, air ionizer, ESD shoe, ESD Garment, ANSI/ESD S20.20

ESD means different things to different people

Page 19: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 19

For Semiconductor Engineer, it means Conductive Packaging

ESD means different things to different people

Page 20: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 20

For Test Engineer, it means ESD GunsESD means different things to different people

Page 21: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 21

ESD means different things to different people

For you Design Engineers, it means:

Bulletproof Design, or ESD ROBUST DesignESD ROBUST Design.

Page 22: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 22

For ESD testing, as for reliability

testing, the purpose of the test is

to verify that the item tested will

operate acceptably in actual use.

Page 23: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 23

In order to achieve this purpose

the test must achieve both

Realism and Repeatability.

Page 24: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 24

If not repeatable, then it cannot

be trusted to detect problems,

or judge the success of solutions.

Page 25: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 25

If the test is not representative

of the reality, then it will not be

successful as a predictor of the

Reliability of the device in the

Real world.

Page 26: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 26

To be considered realistic, an ESD TESTESD TEST

must Recreate the key components of an

actual ESD Threat.

IC’s fail due to Excessive Voltage or EnergyEnergy

Page 27: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 27

Excessive VoltageExcessive Voltage can cause

Dielectric BreakdownDielectric Breakdown in IC’s

such as Oxide Barriers.

Page 28: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 28

Excessive Energy can cause Thermal Failure

by “Melting Silicon” or “Metallization” of IC.

Melting Temperature of Silicon ~ 1,420Melting Temperature of Silicon ~ 1,42000CC

Melting Temperature of Metallization ~ 600Melting Temperature of Metallization ~ 60000CC

Page 29: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 29

One might expect metal would always be damaged first.

Thermal Conductivity of Metal is >> Thermal Conductivity of Silicon.

Short, Intense Pulse may deposit Energy in

Silicon more quickly than Silicon can

spread and dissipate the resulting Heat.

Page 30: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 30

Metallization

Page 31: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 31

Metallization

Page 32: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 32

Metallization

Page 33: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 33

Pre-ESD Capacitor Characteristics

Page 34: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 34

Post-ESD Capacitor Damage

DC – 20 kHz

Page 35: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 35

Post-ESD Capacitor Damage

DC – 20 kHz

Page 36: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 36

IC Level ESD Standards DO NOT Test for Soft-Errors (Bit Errors, Upsets, Resets, etc..). They only test if the ICs are Damaged by ESD

Page 37: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 37

System Level ESD Test Standards applied to operating systems while observing the functionality of the system in addition to observing for any damages.

Page 38: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 38

System Level Human ESD Model is based on a Discharge of a Human via a piece of Metal.

IC Level ESD Model is based on a Discharge from the Skin to Grounded IC

Page 39: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 39

ESD is Not only a Broadband Event, but an ESD test is a Combination of Different Physical Stresses to a System.

Page 40: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 40

Electrostatic Problems:

Manufacturing.Field Operation.

Page 41: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 41

ESD Solutions:

Manufacturing ESD Control Program

Field Failures ESD Robust Design

Page 42: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 42

Important Distinction“ESD Control Program” during

Manufacturing Does NOT

imply “ESD Robust Product” !

Page 43: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 43

Hard FailuresJunction burnoutIC metal burnoutDielectric breakdownTransient Interference

Soft FailuresLogic ErrorsSystem ResetLost DataLost program Flow

Page 44: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 44

Direct Connection

Secondary Arcing

Electric Field

Magnetic Field

Page 45: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 45

Page 46: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 46

Page 47: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 47

ESD voltages as high as 30 kV has been observed in automotive environment.ESD is rich in high-frequency (> 3 GHz) !ESD event can create currents in excess of 30 Amps!ESD currents can destroy IC’s, PCB traces and other

components.ESD can create time-varying Magnetic Field: 25 A/m.ESD can create time-varying Electric Field as high as: 10 kV/m.ESD can create Susceptibility Problems.

Page 48: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 48

Page 49: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 49

ESD phenomena involves Electrical & Thermal Electrical & Thermal

TransportsTransports on the Scale of nanometers (nm), Circuits

and Electronics on the Scale of micrometers (µm),

Semiconductor Chip designs range from picoseconds

(ps) to microseconds (µs), Electrical Currents of interest

range from mA to 10’s of Amperes.Voltages range from

Volts to kiloVolts (kV). Temperatures vary from room

temperature to melting temperatures of 1000’s 0K…….

Page 50: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 50

Must Quantify the Scale in Space & TimeSpace & TimeESD phenomena involves:

Microscopic to Macroscopic Scales.

ESD is a Thermo-Electric Transport of Material Physics

Page 51: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 51

Page 52: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 52

Electrostatic Equilibrium, Post-ESD

Φ−∇=|| Er

Electrostatic Field, Pre-ESD

0E ,0 ==Φr

ESD Physics

Page 53: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 53

Tribos - Greek for "rubbing"

The triboelectric effect is a type of contact

electrification in which certain materials become

electrically charged after they come into contact

with another different material and are then

separated.

ESD Physics

Page 54: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 54

Positive (+)1) Air

2) Human Skin

3) Asbestos

4) Glass

5) Mica

6) Human Hair

7) Nylon

8) Wool

9) Fur

10) Lead

11) Silk

12) Aluminum

13) Paper

14) Cotton

15) Wood

16) Steel

17) Sealing Wax

18) Hard Robber

19) Mylar

20) Epoxy Glass

21) Nickel, Copper

22) Brass, Silver

21) Gold, Platinum

22) Polystyrene foam

23) Acrylic

24) Polyester

25) Celluloid

26) Orlon

27) Polyethylene foam

28) Polyethylene

29) PVC (Vinyl)

30) Silicon

31) Teflon Negative (-)

Triboelectric Series

Page 55: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 55

1.5 kV18 kVSitting on chair padded with Polyurethane foam

1.2 kV20 kVPicking up common Polyethylene bag

600 Volts7 kVOpening a Vinyl envelope

100 Volts6 kVWorker moving at bench

250 Volts12 kVWalking on Vinyl Floor

1.5 kV35 kVWalking across carpet

65% to 90% Relative Humidity

10% to 20 % Relative Humidity

Means of Static Generation

Typical Electrostatic VoltagesTypical Electrostatic Voltages

Page 56: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 56

Capacitance – ESD

Charge Storage Element

Page 57: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 57

⎟⎟⎠

⎞⎜⎜⎝

⎛−

=

21

114

rr

C πε

r1

r2

( ) pF 50C sphere,diameter

meter 1 toarea surfacea has humana pF, 111/1085.8 space, freefor and ,r

BodyHuman

122

≈⇒≈×=

×=∞⇒ −

rCmFif ε

Charge Storage CapacitanceCharge Storage Capacitance

Page 58: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 58

1 pFAn object a size of marble

700 µFEarth’s Capacitance

50 pFHuman Body Capacitance

In addition, we must consider In addition, we must consider Parallel Plate Parallel Plate CapacitanceCapacitance due to the proximity of an object due to the proximity of an object to the surroundingto the surrounding

FreeFree--Space CapacitanceSpace Capacitance

Page 59: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 59

100 pF

50 pF to infinity

50 - 100 pF

500 Ω to 10 kΩ

Self-Capacitance

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

Page 60: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 60

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

Therefore, the Capacitance of a Human Body is Therefore, the Capacitance of a Human Body is the Combination of Freethe Combination of Free--Space Capacitance Space Capacitance ++ParallelParallel--Plate Capacitance and can vary from Plate Capacitance and can vary from

50 50 pFpF to 250 to 250 pFpF

Page 61: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 61

kVtoVkR

pFC

HB

HB

HB

25 0 10 500

25050

=Ω−Ω=

−=

VHB

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

Page 62: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 62

mJ 30 Energy

)000,25(1010021

21 2122

×××== −CVEnergy

For a Human Body of 100 pF Capacitance, Charged Up

to 25 kVolt, Energy Released Per Discharge…….

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

Page 63: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 63

The Discharge of a Human (via a small, hand-held metal piece) is basis for the current waveform most often used IEC 61000-4-2 standard.

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

Page 64: “ESD Phenomena” ESD Mitigation Techniques Events/IEEE_ESD_April_2_2008.pdf · “ESD Phenomena” ESD Mitigation Techniques Cyrous Rostamzadeh. ... In the 1980’s with the growth

April 2, 2008 Cyrous Rostamzadeh 64

GM3097 (July 2006)

Ford ES-XW6T-1A276-AC

Chrysler DC 11224ISO 10605 (2001) & IEC 61000ISO 10605 (2001) & IEC 61000--44--22 Standards with some Modifications.

Ambient Temperature: 23 +/- 3oC Relative Humidity 20 to 40% Prefer 20oC and 30% RH.Contact Rise Time: tr < 1 nsAir Discharge Rise Time: tr < 20 ns. Discharge Networks: 150 pF/2 kΩ and 330 pF/2 kΩ

OEM ESD Test ParametersOEM ESD Test Parameters

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April 2, 2008 Cyrous Rostamzadeh 65

1.1.Electrostatic,Electrostatic, describing the ChargingCharging and Charge Charge DistributionDistribution prior to Breakdown.

Events during an ESD Discharge

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April 2, 2008 Cyrous Rostamzadeh 66

From Static to GHz PropagationFrom Static to GHz PropagationHuman ESD: The beginning scenario is a Human holding a small piece of metal (e.g., a key, ring, screwdriver). He has been charged and is approaching a grounded part of a system.

Events during an ESD Discharge

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April 2, 2008 Cyrous Rostamzadeh 67

2. Physics of Sparking,Physics of Sparking,describing the development of the Conductivity in the Arc.

Events during an ESD Discharge

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April 2, 2008 Cyrous Rostamzadeh 68

3.3. Fast Transient Fast Transient ElectromagneticsElectromagnetics,during the first phase of the Discharge EM WavesDischarge EM Waves travel on DUT. Local differences and Temporal Changes are

Strong. Consequently, the Structure is Electrically Large; Antenna

Theory, Shielding and Coupling are the appropriate methods for

describing ESD in this phase. Picture this as if a 3 GHz pulses

impinges on the DUT.

Events during an ESD Discharge

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April 2, 2008 Cyrous Rostamzadeh 69

4.4. Slower Currents and Charge Slower Currents and Charge Redistribution, Redistribution, after the first phase

Current and Voltage derivatives have been

reduced by Radiation and Reflection to levels

that the dominating frequencies are slow

enough, such that the structure can be treated as

Electrically Small, A description by equivalent

circuit is suitable in this phase of the discharge.

Events during an ESD Discharge

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April 2, 2008 Cyrous Rostamzadeh 70

Fast Transient Electromagnetic Fast Transient Electromagnetic Phase is the most challenging, but it Phase is the most challenging, but it is the Rootis the Root--Cause for Most of the Cause for Most of the SoftSoft--Errors Observed. One should Errors Observed. One should Concentrate on Currents and Concentrate on Currents and Voltages present during this phase Voltages present during this phase of the Discharge.of the Discharge.

Fast Transient Phase of ESD Discharge

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April 2, 2008 Cyrous Rostamzadeh 71

1-15 kV, 0.7 – 1 ns time3.75 A/kV Peak Current

Soft-Error (upset, Reset) and Hard Error (Damage)

IEC 61000-4-2Human Discharging through a small piece of metal

Main ParametersFailure IndicationStandard/ModelReference Event

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April 2, 2008 Cyrous Rostamzadeh 72

System level upset, and damageOnly damage to the IC

Most test up to 8000 VoltsVoltage usually < 4000 Volts

trise < 850 pstrise < 5 ns

Rseries = 330 ΩRseries = 1500 Ω

C = 150 pFC = 150 pF

System Level HBMIC Level HBM (Human Body Model)

IC Level – System Level ESD

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April 2, 2008 Cyrous Rostamzadeh 73

ESD Process is associated with Strong Electromagnetic Fields

Example: for 5 kV discharge:

•18 Amp Peak Current,

•Rise Time of 850 ps,

•|E| = 10 kV/m (10 cm distance)

•|H| = 25 A/m (10 cm distance)

5 kV ESD Discharge

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April 2, 2008 Cyrous Rostamzadeh 74

1.Human Body Model (HBM)

2.Charged Device Model (CDM)

3.Machine Model (MM)

4.Transmission Line Pulse Model (TLP)

ESD Modeling

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April 2, 2008 Cyrous Rostamzadeh 75

Prior to Discharge………

an Electrostatic Field exists.

There is NO Current flowing (or only very little Current).

Therefore, NO relevant Magnetic Field is present.

Events during an ESD Discharge

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April 2, 2008 Cyrous Rostamzadeh 76

Once the Distance is sufficiently small………a Dielectric Breakdown will occur…………….The Electric Field Starts Collapsing……..It collapses down to about 25 - 40 V within 50 ps-5 ns...The collapse time depends on Arc Parameters, Voltage,……

Events during an ESD Discharge

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April 2, 2008 Cyrous Rostamzadeh 77

Events during an ESD Discharge

A Current starts flowing on the metal part and the DUT. The foremost current front expands with the velocity of light. Within the 800 ps it has reached the arm of the person. Current will expand further on the DUT and the arm. It will experience Reflections and Losses due to Radiation and Resistance …complex pattern of Current Density of the DUT and the person. During this phase the person and the DUT act an antenna. This phase is about 10 ns long. The Highest frequency components of the current will be attenuated mainly due to Radiation leading to a smoother current (less high frequency)

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April 2, 2008 Cyrous Rostamzadeh 78

As the higher frequency components do not dominate anymore a description as equivalent circuit is possible for a time frame from about 10 ns until the body reaches a new electrostatic equilibrium. The remaining charge may not zero, as the arc might extinguish before this has been reached. If the hand is approaching the DUT further, a second discharge will occur at a lower voltage. This can lead to a sequence of ESDs, each one at a lower voltage, but each one having a faster rise time.

Events during an ESD Discharge

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April 2, 2008 Cyrous Rostamzadeh 79

ESD Mathematical Analysis

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April 2, 2008 Cyrous Rostamzadeh 80

⎟⎟⎠

⎞⎜⎜⎝

⎛ −•

⎟⎟⎠

⎞⎜⎜⎝

⎛+

⎟⎟⎠

⎞⎜⎜⎝

•+⎟⎟⎠

⎞⎜⎜⎝

⎛ −•

⎟⎟⎠

⎞⎜⎜⎝

⎛+

⎟⎟⎠

⎞⎜⎜⎝

•=4

3

3

2

2

2

1

1

1

1 exp

1

exp

1

)(τ

τ

ττ

τ

τ t

t

t

kit

t

t

kiti n

n

n

n

, exp/1

1

2

2

11 ⎟

⎜⎜

⎛⎟⎟⎠

⎞⎜⎜⎝

⎛−=

nnkττ

ττ

⎟⎟

⎜⎜

⎛⎟⎟⎠

⎞⎜⎜⎝

⎛−=

nnk

/1

3

4

4

32 exp

ττ

ττ

τ4 = 58 nsτ2 = 1.7 nsI2 = 10.1 Amp

n = 3τ3 = 6 nsτ1 = 1.3 nsI1 = 21.9 Amp

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April 2, 2008 Cyrous Rostamzadeh 81

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April 2, 2008 Cyrous Rostamzadeh 82

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April 2, 2008 Cyrous Rostamzadeh 83

HBM ESD Time ConstantHBM ESD Time Constant

nspFCR

HB

HBHBHB

150 100 1500 =×Ω==

ττ

Similar to Thermal Diffusion Time of many

materials used in semiconductor industry

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April 2, 2008 Cyrous Rostamzadeh 84

ESD is a Non-Linear Electro-Thermal Physical Event.

Very Difficult to Model Accurately.

Simple Linear Model is insightful.

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April 2, 2008 Cyrous Rostamzadeh 85

MM ESD Time ConstantMM ESD Time Constant

nspFtoCR

MM

MMMMMM

2 200 )25 10( =×Ω==

ττ

Typically 100 times faster than HB time constant, and

it is oscillatory. Protection needed is 5 to 10 times lower

than required for HB protection.

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April 2, 2008 Cyrous Rostamzadeh 86

VGen = 8 kV

ESD Generator Model

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April 2, 2008 Cyrous Rostamzadeh 87

Time (ns)

Cur

rent

(A)

VGen = 8 kV

ESD Generator Model

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April 2, 2008 Cyrous Rostamzadeh 88

VHBM = 25 kVESD HBM Model

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April 2, 2008 Cyrous Rostamzadeh 89

Time (ns)

Cur

rent

(A)

VHBM = 25 kV

ESD HBM Model

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April 2, 2008 Cyrous Rostamzadeh 90

“PCB Via”“ESD Protection Interconnect Dilemma”

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April 2, 2008 Cyrous Rostamzadeh 91

S = Via Separation, in.

R = Via Radius, in.

H = Via Length, in.

L = Inductance, nH.

Inductance between 2 Connector Pins or Vias

⎟⎠⎞

⎜⎝⎛××=

RSHL elog16.10

ESD Protection Interconnect Dilemma

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April 2, 2008 Cyrous Rostamzadeh 92

⎟⎠⎞

⎜⎝⎛××=

RSHL elog16.10

ESD Protection Interconnect Dilemma

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April 2, 2008 Cyrous Rostamzadeh 93

⎥⎦

⎤⎢⎣

⎡+⎟

⎠⎞

⎜⎝⎛= 14ln08.5via d

hhL

h

d

Typical Value

Lvia = 1 nH

ESD Protection Interconnect Dilemma

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April 2, 2008 Cyrous Rostamzadeh 94

Ω==

====

⎥⎦

⎤⎢⎣

⎡+⎟

⎠⎞

⎜⎝⎛=

8.3X

nH 1.2 Lns 1tmil 16 dmil 63

14ln08.5

L

r

via

rtL

hdhhL

π

h

d

ESD Protection Interconnect Dilemma

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April 2, 2008 Cyrous Rostamzadeh 95

12

1via

41.1DDTDC r

−=

ε

Clearance Hole

Pad

Typical Value

Cvia = 0.5 pF

ESD Protection Interconnect Dilemma

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April 2, 2008 Cyrous Rostamzadeh 96

Pad

Example: Via Pad Diameter = 0.8 mm

Via Hole Diameter = 0.3 mm (----> 0.25 mm)

h = 1.6 mm,or 63 mil

Clearance Hole

ESD Protection Interconnect Dilemma

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April 2, 2008 Cyrous Rostamzadeh 97

D2 = Diameter of Clearance hole in GND Plane, in.

D1 = Diameter of pad surrounding via, in.

T = Thickness of printed circuit board, in

C = Capacitance in pF.

Typical Value

Cvia = 0.5 pF

12

1via

41.1DDTDC r

−=

ε

Clearance Hole

Pad

Inner Layer GND Planer

D2 = Diameter of Clearance hole in GND Plane, in.

D1 = Diameter of pad surrounding via, in.

T = Thickness of printed circuit board, in

C = Capacitance in pF.

Typical Value

Cvia = 0.5 pF

12

1via

41.1DDTDC r

−=

ε

Clearance Hole

Pad

Inner Layer GND Planer

ESD Protection Interconnect Dilemma

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April 2, 2008 Cyrous Rostamzadeh 98

ESD Failure Modes

Direct Hit.Direct Hit.

PrePre--ESD Electric Field.ESD Electric Field.

Magnetic Field.Magnetic Field.

Electromagnetic Field.Electromagnetic Field.

Ground Bounce. Ground Bounce.

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April 2, 2008 Cyrous Rostamzadeh 99

Avoid Avoid Direct ConnectionDirect Connection from an exposed from an exposed external point to an Integrated Circuit.external point to an Integrated Circuit.

ESD Strategies

““E ~ 30 E ~ 30 mJmJ””

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April 2, 2008 Cyrous Rostamzadeh 100

ESD Strategies

In no case should there be a directIn no case should there be a direct

connection from an Integrated Circuitconnection from an Integrated Circuit

to an exposed external point. to an exposed external point.

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April 2, 2008 Cyrous Rostamzadeh 101

ESD Strategies

Divert or limit the ESD Energy awayDivert or limit the ESD Energy away

from Circuit Inputs using Filters orfrom Circuit Inputs using Filters or

Transient Suppressors. Transient Suppressors.

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April 2, 2008 Cyrous Rostamzadeh 102

ESD Strategies

Determine the most vulnerable internal Determine the most vulnerable internal

circuits. Most likely to be upset by circuits. Most likely to be upset by

Electromagnetic EffectsElectromagnetic Effects……Resets, Resets,

Interrupts and critical control lines. Interrupts and critical control lines.

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April 2, 2008 Cyrous Rostamzadeh 103

ESD Capacitor…?100 pF, 1 nF, 10 nF, 47 nF 100 nF…?

MLCC 0805, 0603, 0402?

100 Volts, 50 Volts?

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April 2, 2008 Cyrous Rostamzadeh 104

ESD Capacitor Value

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April 2, 2008 Cyrous Rostamzadeh 105

ESD Capacitor Mounting Strategy

How far from Connector Pin…

PCB layer stackup…

Y-Connection…

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April 2, 2008 Cyrous Rostamzadeh 106

ESD Capacitor Failure Mode

Voltage – Pressure

Current – Force

Dielectric Breakdown

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April 2, 2008 Cyrous Rostamzadeh 107

IHF

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April 2, 2008 Cyrous Rostamzadeh 108

SolutionSolutionESD Strategies

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April 2, 2008 Cyrous Rostamzadeh 109

SolutionSolutionESD Strategies

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April 2, 2008 Cyrous Rostamzadeh 110

SolutionSolutionESD Strategies

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April 2, 2008 Cyrous Rostamzadeh 111

Use LOW Capacitance Protection

High Capacitance Protection --- 6X Longer Delay Time Low Capacitance Protection

SolutionSolution

ESD Strategies

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April 2, 2008 Cyrous Rostamzadeh 112

IHF

SolutionSolutionESD Strategies

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April 2, 2008 Cyrous Rostamzadeh 113

l > λ

ESD

““Fast Transient Fast Transient ElectromagneticsElectromagnetics””

Structure “Electrically Large”

Frequency ~ 3 GHz

Field Collapses to 25 Field Collapses to 25 -- 40 V within 40 V within ““50 50 psps –– 5 ns5 ns””

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April 2, 2008 Cyrous Rostamzadeh 114

1. TVS (Transient Voltage Suppressor)2. MOV Multilayer Zinc Oxide3. Diode4. Capacitor5. Spark Gap6. Filters7. Ferrites

ESD Protection Devices

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April 2, 2008 Cyrous Rostamzadeh 115

Capacitor Placement

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April 2, 2008 Cyrous Rostamzadeh 116

20 nH

20 nHReturn

ESD Protection Interconnect Dilemma

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April 2, 2008 Cyrous Rostamzadeh 117

0 nHReturn

20 nH20 nH

ESD Protection Interconnect Dilemma

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April 2, 2008 Cyrous Rostamzadeh 118

7.94 MHz

20 nH

20 nHReturn

C = 10 nF

ESL = 200 pH

ESR = 22 mΩ

ESD Protection Interconnect Dilemma

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April 2, 2008 Cyrous Rostamzadeh 119

11.27 MHz

20 nH

0 nHReturn

C = 10 nF

ESL = 200 pH

ESR = 22 mΩ

ESD Protection Interconnect Dilemma

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April 2, 2008 Cyrous Rostamzadeh 120

112.98 MHz0 nH

Return

20 nH20 nH

C = 10 nF

ESL = 200 pH

ESR = 22 mΩ

ESD Protection Interconnect Dilemma

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Poor Better Best

ESD Protection Interconnect Dilemma

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ESD Protection Interconnect Dilemma•All dimensions are in inches

0.0075

0603 Skinny

0603 Capacitor

0.030 square soldering pad 0.050

0.024 round via pad

0.010 dia. hole

0.030

0603 Fat

0603 Capacitor

0.030 square soldering pad 0.050

0.024 round via pad0.010 dia. hole

0603 end

0402 end Same via

and hole

0.020 squaresoldering pad

0402 side

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0.210.250.320.430.260.320.400.600402 side

0.380.440.580.820.420.500.671.010402 end

0.330.380.510.670.360.460.610.850603 side

0.420.530.681.070.500.590.771.160603 end

0.891.121.472.070.951.171.522.230603 fat

1.511.662.132.681.511.772.182.870603 skinny

0.0040.0060.0100.0200.0040.0060.0100.020Via Length

Hole Diameter 0.020 inHole Diameter 0.010 in

ESD Protection Interconnect Dilemma

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ESD Strategies

High Density Connector Restricts

Optimized Mounting Strategy

For ESD Capacitors.

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Prevent ESD Current flow into PCB Ground Structure.This problem can be sneaky!

Do NOT assume PCB Ground has a low Impedance!tr = 1nsec (300 MHz +), ZGround is NOT LOW!

Ground BOUNCE CMOS Latch-up. In reality ESD does NOT cause

damage; it just sets things up so the power supply can destroy the part!

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Due to ESD Transient Nature:Fast (edge rate ~< 1 nsec) Digital Circuits are

Highly Susceptible!Slow Analog Circuits are Immune!

NOTE: This is NOT a Direct ESD Discharge!It is due to Electromagnetic Fields and Pre-ESD Electric Field.

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Minimize interconnect Inductance.

Use lowest value Capacitors to prevent degradation of High-Speed signals.

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Spark Gap “Protection Mechanism”

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Spark Gap

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April 2, 2008 Cyrous Rostamzadeh 136

Vs/m 105-2 Constant Process

)()()(

length arc d Process; SurfacePressure Normalat Vs/m 108 Constant

)()()(

:Process" Discharge Gas" LawTopler

4-0

4-0

×≈=

⋅⋅

=

=×≈=

⋅⋅

=

Surfacea

dIdatUtI

Toplera

dIdatUtI

M

t

surfM

arcsurf

T

t

gasT

arcgas

ζξ

ζξ

Spark Gap Physics

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PSPICE Model for Spark Gap

RHB = 330 Ω

CHB = 150 pF

< 0.1 uH Iarc (t)

Isurf (t) Igas (t)

Cgap

Spark Gap

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April 2, 2008 Cyrous Rostamzadeh 138

Spark Gap

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April 2, 2008 Cyrous Rostamzadeh 139

Spark Gap

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April 2, 2008 Cyrous Rostamzadeh 140

Connector Area ESD Capacitors

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April 2, 2008 Cyrous Rostamzadeh 141

Connector Area ESD Capacitors

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April 2, 2008 Cyrous Rostamzadeh 142

High Frequency Design Practice ESD

ESD

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April 2, 2008 Cyrous Rostamzadeh 143

ESD Exteremely Fast Transient

ESD Has Several Failure Modes

Several Design Tactics

Several Strategic Concepts

ESD Circuit Protection

ESD Grounds

ESD Shuelding

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Thank you for your

Participation.