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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.
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