TM Burn-in & Test Socket Workshop · Rubbing two non conducting materials together. BITS 2005...

Burn-in & TestSocket Workshop

ARCHIVE

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

Mesa, Arizona

TM

Burn-in & Test SocketWorkshop

COPYRIGHT NOTICE• The papers in this publication comprise the proceedings of the 2005

BiTS Workshop. They reflect the authors’ opinions and are reproducedas presented , without change. Their inclusion in this publication doesnot constitute an endorsement by the BiTS Workshop, the sponsors,

BiTS Workshop LLC, or the authors.

• There is NO copyright protection claimed by this publication or theauthors. However, each presentation is the work of the authors and

their respective companies: as such, it is strongly suggested that anyuse reflect proper acknowledgement to the appropriate source. Anyquestions regarding the use of any materials presented should be

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

BITS 2005 Methods of preventing ESD in module testing.

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

BITS 2005 Methods of preventing ESD in module testing.

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

BITS 2005 Methods of preventing ESD in module testing.

5

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 Methods of preventing ESD in module testing.

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

BITS 2005 Methods of preventing ESD in module testing.

7

Static Charge Buildup in Socket

insulator

Electrostatic charge build up during module insertion

BITS 2005 Methods of preventing ESD in module testing.

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

BITS 2005 Methods of preventing ESD in module testing.

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

BITS 2005 Methods of preventing ESD in module testing.

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

BITS 2005 Methods of preventing ESD in module testing.

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

BITS 2005 Methods of preventing ESD in module testing.

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

BITS 2005 Methods of preventing ESD in module testing.

13

IBM ESD Socket

insulator

conductor

No static charge buildup at module insertion

BITS 2005 Methods of preventing ESD in module testing.

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

BITS 2005 Methods of preventing ESD in module testing.

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

BITS 2005 Methods of preventing ESD in module testing.

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.