ESD - BiTS Workshop

Burn-in & Test 

Socket Workshop 

March 6-9, 2005 

Hilton Phoenix East / Mesa Hotel 

Mesa, Arizona 

ARCHIVE 

TM

Burn-in & Test Socket 

Workshop 

TM 

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• The BiTS logo and ‘Burn-in & Test Socket Workshop’ are trademarks 

of BiTS Workshop LLC.

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Hot Topics Session 

Tuesday 3/08/05 3:30PM 

CONTROLLING ESD 

Technical Program 

“Methods Of Preventing ESD In Module Testing” 

Zen Podpora – IBM Microelectronics 

Qifang (Michelle) Qiao – IBM Microelectronics Patrick Rafter – IBM Microelectronics 

“New ESD Control Polymers” 

Naomitsu Nishihata – Kureha Chemical Industry Co., Ltd.

METHODS OF 

PREVENTING ESD IN 

MODULE TESTING 

2005 Burn-in and Test Socket Workshop 

Zen Podpora 

Michelle Qiao 

Patrick Rafter 

Contacting Systems Engineering 

IBM Microelectronics

Objectives 

• ESD overview 

• Impact of ESD on module test 

• Methods of ESD prevention 

BITS 2005 

Methods of preventing ESD in 

module testing. 

2

Agenda 

• What is static electricity 

• Causes of static charge buildup 

• Impact of ESD on product and test 

equipment 

• Conventional ESD prevention methods and 

their deficiencies 

• IBM ESD socket design 

BITS 2005 



3

What is Static Electricity? 

• Simply electricity at rest 

– No current flowing 

• Surface phenomenon 

– Static charge is dependent on surface area 

• Coulomb's law; F = k (Q 1 X Q 2 ) / d 2 

– Electric force between charges at rest 

BITS 2005 



4

Static Charge Buildup 

• Electric 

phenomenon in 

which intimate 

contact transfers 

charged particles 

from one body to 

another 

Rubbing two non conducting materials together 

BITS 2005 



5

Static Charge Buildup 

• Only insulative materials build up static 

charge 

– Insulative material surface resistivity 

> 10 12 ohms / sq 

• Socket components comprise insulative 

materials 

– Static charge build up from module insertion into 

socket 

BITS 2005 



6

Static Charge Buildup in Socket 

insulator 

Electrostatic charge build up during module insertion 

BITS 2005 



7

Electrostatic Discharge [ESD] 

• Common ESD 

events 

– Lightning 

– Walk across the rug 

and reach doorknob 

• Module test events 

– Charged operator 

reaching IC module 

– Charged socket 

discharging thru the 

tester 

Discharge of build up 

of static electricity 

BITS 2005 



8

Common Causes of ESD Damage 

• Human Body Model (HBM) 99.9% 

– ESDS transportation 

– Air blow-off operations 

– IC handling equipment 

BITS 2005 



9

Impact of ESD 

• Electrostatic Discharge (ESD) destroys 

electronic hardware 

– Immediate failures - distractive damage 

• Direct-current resulting in junction burnout, 

shorts, dielectric breakdown, and metallization 

melt 

– Latent failures (field failures), days, weeks, 

months later 

• ESD creates problems which cost industry 

billions of dollars per year 

BITS 2005 



10

Conventional ESD Prevention 

• Grounding 

– Personnel 

– Equipment 

• Ionization 

– Ionizing units neutralize charged particles 

• Use of resistive materials 

– Surface resistivity 10 6 10 9 ohms (carbon mix) 

• Humidity control 

– Relative humidity greater than 50% will minimize 

ESD problems 

BITS 2005 



11

Problems with Conventional ESD 

Prevention 

• Resistive materials 

• Non uniform carbon distribution (hot pockets) 

• Leakage currents 

• Humidity control 

• Condensation problem at low temp test 

• Grounding 

• Operators bypass ESD procedures 

BITS 2005 



12

IBM ESD Socket 

conductor 

insulator 

No static charge buildup at module insertion 

BITS 2005 



13

IBM ESD Socket 

• Alignment plate frame 

– Made from 

conductive material 

[< 10 4 ohms/sq] 

– Will not store electric 

charge 

• Alignment plate grid 

– Made from insulative 

material 

[> 10 12 ohms/sq] 

– Will not cause 

leakage currents 

conductor 

insulator 

BITS 2005 



14

ESD Facts 

• CMOS chips damage as little as 50V 

• If you feel a ‘shock’ at least 3kV 

• Walking across a carpet 1.5kV to 35kV 

• Brushing your hair 1.2kV to 27kV 

• Not getting ZAPPED priceless 

BITS 2005 



15

Reference Materials 

• Basics of Static Electricity by Ron Kurtus (revised 28 August 2004 

– www.school-for-champions.com 

• The Most Common Causes Of ESD Damage by Roger J. 

Peirce, ESD Technical Services 

– http://www.evaluationengineering.com/default.asp 

• WHAT IS STATIC ELECTRICITY? by SCIENCE MADE SIMPLE 

– http://www.sciencemadesimple.com/index.html 

• What is ESD ? By Research Machines plc 

– http://www.rm.com/ 

• ESD Is Shocking Experience for Electronics by Ron Brewer, 

Instrument Specialties, P.O. Box 650, Delaware Water Gap, PA 18327, (570) 424-8510. 

BITS 2005 



16

New ESD Control Polymers 

Naomitsu Nishihata 

Kureha Chemical Industry Co., Ltd. 



TM 

2005 Burn-in and Test Socket Workshop 

March 6 - 9, 2005

Agenda 

• What is ESD 

• Material for socket 

• Technology review 

• New technology 

• Sample preparation 

• Characterization 

• Conclusion 

11/12/2002 

BiTS 2005 

2

What is ESD 

An ESD occurrence requires all three events: 

•Charge generation 

•Charge accumulation 

•Rapid discharge 

11/12/2002 


3

What is ESD 

•Human Body Model: Discharged from 

operators 

•Charged Device Model: Device charged up 

and pins contact ground. 

•Machine Model: Discharge from machine 

members 

11/12/2002 


4

Material for socket 

• Temperature considerations 

– Test: -55 o C to 150 o C? 

• Machinability 

• Leakage current threshold 

• ESD control properties 

10 6 -10 11 ohms/sq. 

Strictly controlled resistance 

• Cleanliness 

Low out-gassing 

Low metal contamination 

• Wear properties 

11/12/2002 


5

Technology review of materials 

Conventional Materials 

• Carbon material-filled compound 

• Metal filled-compound 

• Antistatic agent added polymer 

• Antistatic polymer blend 

11/12/2002 


6

Technology review of materials 

Technology 

ESD control 

Cleanliness 

Heat and 

properties 

chemical 

resistance 

Carbon 

Unstable 

Good 

Good 

Metal 

Unstable 

Limited use 

Good 

Antistatic agent 

Limited use 

Poor 

Poor 

Antistatic 

Limited use 

Limited use 

Poor 

polymer blend 

11/12/2002 


7

New Technology 

• Combine a special carbon material having 

moderately conductive resistance with a 

polymer. 

• Optimize production process 

11/12/2002 


8

Raw Materials 

Sample preparation 

• Polyetheretherketone resin (PEEK) 

• Special carbon with resistivity of 10 7 10 8 and 10 9 

ohms/sq. 

• PAN-based carbon fiber 

Procedure 

• Raw material blend 

• Extrusion 

• Injection molding 

• Characterization 

11/12/2002 


9

Characterization 

• Resistance vs carbon content 

• Resistance fluctuation 

• Resistance change against applied voltage 

• Resistance of inner layer 

• Static decay time vs resistance 

• Residual peak voltage vs resistance 

• Peak current analysis on ESD 

• Leak current analysis of a socket 

• Other properties 

11/12/2002 


10

Surface resistance (ohms) 

Resistance of Composites 

1.E+14 

1.E+12 

1.E+10 

PEEK/Special Carbon 

1.E+08 

1.E+06 

1.E+04 

1.E+02 

PEEK/CF 

1.E+00 

10 15 20 25 30 35 40 

11/12/2002 

Carbon content (%) 


11

Resistivity Fluctuation 

Diameter of guide electrode : 9mm 

Applied voltage : 10V, 100V, 500V 

GATE 

Current measure part 

electrode 

electrode 

64mm 

1 2 3 

4 5 6 

7 8 9 

100mm 

3mm 

ESD-STM11.11 

9 mm 

11/12/2002 


Small type 

12

Resistivity Fluctuation 


1.E+13 

1.E+11 

1.E+09 

1.E+07 

1.E+05 

11/12/2002 

Applied voltage: 100V 


PEEK/CF 

1 2 3 4 5 6 7 8 9 

Position 


13

Resistivity vs Voltage 

1.E+15 


11/12/2002 

1.E+13 

1.E+11 

1.E+09 

1.E+07 

1.E+05 

PEEK/CF 


1 10 100 1000 

Applied voltage (V) 


14


11/12/2002 

Resistivity of Inner Layer 

1.E+10 

1.E+08 


1.E+06 

1.E+04 

PEEK/CF 

1.E+02 

1.E+00 

0 0.5 1 1.5 

Machined amount (mm) 

15 

BiTS 2005

Static decay time 

1000V electric source + monitor 

clip 

ground + 

sample 

SDT measurement using Charged Plate Monitor 

Static decay time 

•The static decay time from 1000V to 5V was measured 

using charged-plate monitor. 

11/12/2002 


16

Resistance vs Voltage 

Static Decay Time(ms) 

2000 

1600 

1200 

800 

400 

1000V to 10V 

11/12/2002 

0 

1.E+08 1.E+09 1.E+10 1.E+11 1.E+12 1.E+13 



17

Hot spot voltage test 

+ 

Surface electrometer 

sample 

Hot spot voltage 

Charged Plate Monitor 

• To search insulative spots on the surface 

• To evaluate homogeneity by measuring residual 

voltage after discharging. 

11/12/2002 


18

Hot spot voltage 

Residual peak voltage (V) 

800 

600 

400 

200 

PEEK/CF 


11/12/2002 

0 

1.E+05 1.E+07 1.E+09 1.E+11 1.E+13 



19

Peak current analysis 

Oscilloscope 

Power supply 

1000V 

sample 

+ 

Charged Plate Monitor 

•Generated current on ESD provides a serious damage to 

devices. 

•Magnitude of peak current on ESD is estimated by 

monitoring wave form during discharging. 

11/12/2002 


20

Peak current analysis 

Peak current (mA) 

1400 

1200 

1000 

800 

600 

400 

200 

0 

1.E+02 1.E+04 1.E+06 1.E+08 1.E+10 

11/12/2002 



21

Leak current analysis 

pA 

Hi Resistance Meter 4439B 

5V 

Pin-Probe 

Specimen 

Insulator 

Column number 

11/12/2002 

3 

2 

1 2 3 

Row number 

Schematic of Current analysis 


0.56mm Measurement point 

0.8mm 

22

Leak current analysis 

Leak current(nA) 

10 

1 

0.1 

0.01 

△ △ 

× × × × 

△ × △ 

△ 

× 

△ 

× × △ × 

× 

1 st row 

× 10 th row 

△ 20 th row 

× 

△ △ △ △ 

△ 

× △ 

× 

△ 

× 

△ 

× 

0.001 

1 5 10 15 20 25 30 

Column number 

11/12/2002 


23

Other properties 

Properties 

Units 

EKH- 

EKH- 

EKH- 

SS07 

SS09 

SS11 

Specific gravity 

- 

1.33 

1.31 

1.31 

Tensile strength 

Mpa 

140 

135 

110 

Rockwell hardness 

M 

scale 

125 

125 

125 

Heat deflection temperature 

1.82MPa 

ºC 

305 

305 

280 

Coefficient of linear thermal 

expansion 30ºC-140ºC 

- 

1.5 

1.5 

1.5 

11/12/2002 


24

Other properties 

Properties 

Units 

EKH- 

EKH- 

EKH- 

SS07 

SS09 

SS11 

Continuous service 

temperature 

ºC 

260 

260 

260 

Dielectric strength 

kV/mm 

- 

2 

5 

Dielectric constant 1MHz 

- 

7.9 

6.6 

5.3 

Dielectric loss tangent 1MHz 

0.22 

0.21 

0.17 

Surface resistance 

ohms 

10 6-7 

10 7-9 

10 9-11 

11/12/2002 


25

Conclusion 

• The ESD control materials having the surface resistivity 

at specific levels within a range of 10 6 to 10 11 ohms 

were obtained by using the technology. 

• The surface resistance fluctuation was very small and 

the surface resistance change against applied voltage 

was small. 

• The suitable surface resistance range of ESD 

protection for socket was estimated in the range of 10 8 

to 10 11 ohms from various ESD characterization. 

11/12/2002 


26

ESD - BiTS Workshop

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