TM Burn-in & Test Socket Workshop · Rubbing two non conducting materials together. BITS 2005 Methods of preventing ESD in module testing. 6 Static Charge Buildup ... Reference Materials

Burn-in & TestSocket Workshop

ARCHIVE

March 6-9, 2005Hilton Phoenix East / Mesa Hotel

Mesa, Arizona

TM

Burn-in & Test SocketWorkshop

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directed to the author/s or their companies.

• The BiTS logo and ‘Burn-in & Test Socket Workshop’ are trademarksof BiTS Workshop LLC.

TM

Burn-in & TestSocket Workshop

tm

Hot Topics SessionTuesday 3/08/05 3:30PM

CONTROLLING ESD“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.

Technical Program

METHODS OF PREVENTING ESD IN

MODULE TESTING

2005 Burn-in and Test Socket Workshop

Zen PodporaMichelle QiaoPatrick Rafter

Contacting Systems EngineeringIBM Microelectronics

BITS 2005 Methods of preventing ESD in module testing.

2

Objectives

• ESD overview

• Impact of ESD on module test

• Methods of ESD prevention


3

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


4

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 (Q1 X Q2) / d2

– Electric force between charges at rest


5

Static Charge Buildup

• Electric phenomenon in which intimate contact transfers charged particles from one body to another

Rubbing two non conducting materials together


6

Static Charge Buildup

• Only insulative materials build up static charge– Insulative material surface resistivity

> 1012 ohms / sq

• Socket components comprise insulative materials– Static charge build up from module insertion into

socket


7

Static Charge Buildup in Socket

insulator

Electrostatic charge build up during module insertion


8

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


9

Common Causes of ESD Damage

• Human Body Model (HBM) <0.10%– Improper grounding– Faulty personal protective equipment– Not following ESD procedures

• Charged Device Module (CDM) >99.9%– ESDS transportation– Air blow-off operations– IC handling equipment


10

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


11

Conventional ESD Prevention• Grounding

– Personnel– Equipment

• Ionization– Ionizing units neutralize charged particles

• Use of resistive materials – Surface resistivity 106<->109 ohms (carbon mix)

• Humidity control– Relative humidity greater than 50% will minimize

ESD problems


12

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


13

IBM ESD Socket

insulator

conductor

No static charge buildup at module insertion


14

IBM ESD Socket• Alignment plate frame

– Made from conductive material [< 104 ohms/sq]

– Will not store electric charge

• Alignment plate grid– Made from insulative

material [> 1012 ohms/sq]

– Will not cause leakage currents

conductor

insulator


15

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


16

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.

New ESD Control Polymers

2005 Burn-in and Test Socket WorkshopMarch 6 - 9, 2005Burn-in & Test

Socket Workshop

TM

Naomitsu Nishihata

Kureha Chemical Industry Co., Ltd.

11/12/2002BiTS 2005

2

Agenda

• What is ESD• Material for socket• Technology review• New technology• Sample preparation• Characterization• Conclusion

11/12/2002BiTS 2005

3

What is ESD

An ESD occurrence requires all three events:

Charge generation

Charge accumulation

Rapid discharge

11/12/2002BiTS 2005

4

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

11/12/2002BiTS 2005

5

Material for socket

• Temperature considerations– Test: -55oC to 150oC?

• Machinability• Leakage current threshold• ESD control properties

106-1011 ohms/sq.Strictly controlled resistance

• CleanlinessLow out-gassingLow metal contamination

• Wear properties

11/12/2002BiTS 2005

6

Technology review of materials

Conventional Materials

• Carbon material-filled compound • Metal filled-compound• Antistatic agent added polymer• Antistatic polymer blend

11/12/2002BiTS 2005

7

Technology review of materials

PoorLimited useLimited useAntistatic

polymer blend

PoorPoorLimited useAntistatic agent

GoodLimited useUnstableMetal

GoodGoodUnstableCarbon

Heat and

chemical

resistance

CleanlinessESD control

properties

Technology

11/12/2002BiTS 2005

8

New Technology

• Combine a special carbon material having moderately conductive resistance with a polymer.

• Optimize production process

11/12/2002BiTS 2005

9

Sample preparation

• Polyetheretherketone resin (PEEK) • Special carbon with resistivity of 107 108 and 109

ohms/sq. • PAN-based carbon fiber

Raw Materials

• Raw material blend• Extrusion • Injection molding• Characterization

Procedure

11/12/2002BiTS 2005

10

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

11/12/2002BiTS 2005

11

Resistance of Composites

1.E+00

1.E+02

1.E+04

1.E+06

1.E+08

1.E+10

1.E+12

1.E+14

10 15 20 25 30 35 40

Carbon content (%)

Sur

face

resi

stan

ce (

ohm

s)

PEEK/Special Carbon

PEEK/CF

11/12/2002BiTS 2005

12

Resistivity Fluctuation

Diameter of guide electrode : 9mmApplied voltage : 10V, 100V, 500V

100mm

1 2 3

4 5 6

7 8 9

GATE

3mm

electrode

electrodeCurrent measure part

64mm

ESD-STM11.11

9 mm

Small type

11/12/2002BiTS 2005

13

Resistivity Fluctuation

1.E+05

1.E+07

1.E+09

1.E+11

1.E+13

1 2 3 4 5 6 7 8 9Position

Su

rfac

e re

sist

ance

(o

hm

s)

PEEK/Special Carbon

PEEK/CF

Applied voltage: 100V

11/12/2002BiTS 2005

14

Resistivity vs Voltage

1.E+05

1.E+07

1.E+09

1.E+11

1.E+13

1.E+15

1 10 100 1000

Applied voltage (V)

Su

rfac

e re

sist

ance

(o

hm

s)

PEEK/Special Carbon

PEEK/CF

11/12/2002BiTS 2005

15

Resistivity of Inner Layer

1.E+00

1.E+02

1.E+04

1.E+06

1.E+08

1.E+10

0 0.5 1 1.5Machined amount (mm)

Su

rfac

e re

sist

ance

(o

hm

s)

PEEK/Special Carbon

PEEK/CF

11/12/2002BiTS 2005

16

Static decay time

SDT measurement using Charged Plate Monitor

Static decay time•The static decay time from 1000V to 5V was measured using charged-plate monitor.

1000V electric source + monitor

ground+ sample

clip

11/12/2002BiTS 2005

17

Resistance vs Voltage

0

400

800

1200

1600

2000

1.E+08 1.E+09 1.E+10 1.E+11 1.E+12 1.E+13Surface resistance (ohms)

Sta

tic D

ecay

Tim

e(m

s)

1000V to 10V

11/12/2002BiTS 2005

18

Hot spot voltage test

sample

Charged Plate Monitor

+

sample

Surface electrometer

Hot spot voltage

• To search insulative spots on the surface

• To evaluate homogeneity by measuring residual voltage after discharging.

11/12/2002BiTS 2005

19

Hot spot voltage

0

200

400

600

800

1.E+05 1.E+07 1.E+09 1.E+11 1.E+13Surface resistance (ohms)

Res

idua

l pea

k vo

ltage

(V

)

PEEK/Special Carbon

PEEK/CF

11/12/2002BiTS 2005

20

Peak current analysis

1000V

+

Power supplyOscilloscope

•Generated current on ESD provides a serious damage to devices.

•Magnitude of peak current on ESD is estimated by monitoring wave form during discharging.

sample

Charged Plate Monitor

11/12/2002BiTS 2005

21

Peak current analysis

0

200

400

600

800

1000

1200

1400

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

Surface resistance (ohms)

Pea

k cu

rren

t (m

A)

11/12/2002BiTS 2005

22

pA

InsulatorSpecimen

Pin-Probe

Hi Resistance Meter 4439B5V

0.56mm

0.8mm

Measurement point

Schematic of Current analysis

321 2 3Row number

Col

umn

num

ber

Leak current analysis

11/12/2002BiTS 2005

23

Leak current analysis

1 5 10 15 20 25 30Column number

Lea

k cu

rren

t(n

A)

0.1

101st row

10th row

0.001

1

0.01

20th row

×× × ××

××

××

×××× ××

△

×

△△△ △△ △△ △ △ △

△△△ △

△

11/12/2002BiTS 2005

24

Other properties

1.51.51.5-Coefficient of linear thermal expansion 30ºC-140ºC

280305305ºCHeat deflection temperature 1.82MPa

125125125M scale

Rockwell hardness

135

1.31

EKH-SS09

110140MpaTensile strength

1.311.33-Specific gravity

EKH-SS11

EKH-SS07

UnitsProperties

11/12/2002BiTS 2005

25

Other properties

0.170.210.22Dielectric loss tangent 1MHz

5.36.67.9-Dielectric constant 1MHz

260260260ºCContinuous service temperature

107-9

2

EKH-SS09

109-11106-7ohmsSurface resistance

5-kV/mmDielectric strength

EKH-SS11

EKH-SS07

UnitsProperties

11/12/2002BiTS 2005

26

Conclusion

• The ESD control materials having the surface resistivityat specific levels within a range of 106 to 1011 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 108

to 1011 ohms from various ESD characterization.

Documents

TM Burn-in & Test Socket Workshop · Rubbing two non conducting materials together. BITS 2005 Methods of preventing ESD in module testing. 6 Static Charge Buildup ... Reference Materials