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118 Journal of KWJS, Vol. 25, No. 2, April, 2007
16
Reliability Assessment for Electronic Assemblies with Electrical and Electrochemical Properties Measurement
Won-Sik Hong, Chul-Min Oh, Noh-Chang Park, Byung-Suk Song and Seung-Boo Jung
1.
,
.
(in-situ)
.
(stress) .
, , ,
.
.
(resistance) (insulation resistance) .
.
.
.
(printed circuit board, PCB)
.
2.
2.1 Daisy chain
PCB .
,
. PCB
(thermal shock test), (thermal cycling
test), (high temperature and high
humidity test), (pressure cooker test,
PCT) . PCB
(plated though hole, PTH)
(crack), (delamination,
blistering) .
daisy chain
.
daisy
chain .
Fig. 1
.
, QFP(quad flat package), BGA
(ball grid array), CSP(chip scale package),
(flip chip)
(dummy chip)
.
. Daisy chain
.
: 3
25 2, 2007 4 119
17
(a)
(b)
Fig. 1 Photographs of test specimen (a) PCB and (b) pa
ckage component on the PCB
.
, ,
(extrapolation)
,
. Die/package daisy
chain die attach,
(underfill), bond/filp chip
. Plastic BGA/CSP
(fail) ,
.
, (CTE
mismatch)
.
.
2.2
,
.
, (shear fatigue
damage) .
( ),
(creep), (stress relaxation), (corrosion),
(oxidation) .
,
.
.
,
1 sec 300
, 1).
,
10% 9
.
300
. 1000
. ,
,
.
daisy chain 1 sec
3001000 (
) ,
1020 %
.
2.3
,
.
.
.
2.4 /
.
. Fig.
2 Daisy chain
. Fig. 3
.
120 Journal of KWJS, Vol. 25, No. 2, April, 2007
18
(a)
(b)
Fig. 2 Fatigue test equipment photographs : (a) overall
shape of test system and (b) magnified view of
test fixture and specimen
Fig. 3 Daisy chain measurement systems : (a) CSP test
coupon, (b) event detector with in-situ method,
(c) DC source meter and (d) test program controller
Fig. 4 In-situ measurement results of resistance and
bending fatigue force applied on the CSP package
solder joints during the 4-point bending fatigue
test
,
(event
detector)
.
. ,
(open)
.
.
, ,
.
1
.
. Fig. 4 4
.
,
CSP
.
.
3.
3.1
(thermal cycling test, TC)
.
,
TC 0100 6,000 cycles
. Fig. 5
.
PCB Tg
. JEDEC 222)
,
.
TC1, TC3, TC4 JEDEC 22 Method A 104, Rev.2
J, G, B 2).
25 2, 2007 4 121
19
Fig. 5 Representative temperature profile for thermal cycle t
est11)
3.2
.
. TC1
6,000 cycles .
63%
.
(Weibull distribution)
(cumulative failure rate, %)
.
. 6,000 cycles ,
1020 /min
.
3.3
(acceleration factor, AF)
.
AF 2 .
(cyclic fatigue life)
AF(cycles)
AF(MTTF) , AF(cycles)
.
(1)
Nf(product) 50%
(the mean fatigue life)
, Nf(test) 50%
.
AF(MTT) .
(2)
f(test) (test cycle
frequency), f(product)
(cyclic frequency) . 4
, Engelmaier-
Wild (fatigue ductility exponent)
m
. AF
,
,
.
4.
(ECM) PCB
.
PCB ,
(paper phenolic laminate)
,
(electro-deposition) 6).
,
.
4.1
(mixed potential theory)3)
.
(half-
cell) (system)
. Fig. 6
.
122 Journal of KWJS, Vol. 25, No. 2, April, 2007
20
Fig. 6 Photographs of polarization test system4)
Log i (A/cm2)
E(V)
ECORR
Anode : M M +e
iCORR
Cathode : M ++e-? M
Tafel Region
Anode : M M+ +e -
i
Cathode : M + +e- M
2 H++2e-H2
Tafel Region
Fig. 7 Schematic diagram of Tafel extrapolation method
for measuring the corrosion rate4)
0.175
0.301
0.264
0.197
0.312
0.227
0.0
0.1
0.2
0.3
0.4
0.5
None Aging 150 220
Aging temperature()
Corr
osi
on r
ate (
mpy)
SnPb
Sn3Ag0.5Cu
180(SnPb)/220
(a)
0.175
0.301
0.264
0.197
0.312
0.227
0.0
0.1
0.2
0.3
0.4
0.5
None Aging 150 220
Aging temperature()
Corr
osi
on r
ate (
mpy)
SnPb
Sn3Ag0.5Cu
180(SnPb)/220
(b)
Fig. 8 Comparisons of corrosion rate between Sn- 40Pb
and Sn-3.0Ag-0.5Cu as follows aging temperatur
e and electrolytes, pH 7.5, 40 vs. SCE : (a) Di
stilled ionized water and (b) 1 mole 3.5 wt% N
aCl electrolyte4)
(Tafel extrapolation) . Fig. 7
(reversible electrode potential)
, (current density,
ICORR) (corrosion Potential, ECORR)
. (anodic
dissolution)
(oxide or hydroxide film)
3).
(ECORR) (ICORR)
.
4.2 4,5)
Sn-40Pb Sn-3.0Ag-0.5Cu(SAC)
.
,
ECORR, ICORR (corrosion
rate) .
mpy(mils/year) .
Fig. 8 4).
0.1750.227 mpy
, 150
SAC
.
Sn3Ag0.5Cu
. 3.5 wt% NaCl
2.9
3.1 mpy , 150
SAC 9.22 mpy, SnPb 5.119 mpy
.
SAC 4.898 mpy,
SnPb 14.370 mpy 3
.
25 2, 2007 4 123
21
.
4.3 THB
7-9)
,
, (water drop
test)
.
-- (temperature-
humidity-bias test, THB) .
PCB
.
(insulation resistance) ,
.
PCB
,
. THB Table
1 IPC-TM-650 2.6.13
2.6.14 JIS-Z-3193, 3284
. Fig. 9 THB
, Fig. 10 (a)
ECM
, (b)
(dendrite) .
(comb pattern)
.
,
. THB
1
/40ms 1/1min
. 1000 40ms 1
, 1 1
Test MethodIPC-TM-650 2.6.13, 2.6.14JIS-Z-3284 Appendix 14JIS-Z-3197 8.5.4
Test Conditions 60, 90%RH / 6.5 Volts Applied
Insulation Resistance Measurement Period
every 40 ms (every 1 min, normally)
Failure Criteria < 106
Test Time at least 1000 hours
Test Chamber
Insulation Resistance Measuring Sys.
Connection Cable
Fig. 9 Photographs of test equipment for temperature- humidi
ty-bias test
1.0E+15
1.0E+14
1.0E+13
1.0E+12
1.0E+11
1.0E+10
1.0E+09
1.0E+08
1.0E+07
1.0E+06
1.0E+05
1.0E+04
1.0E+03
1.0E+02
1.0E+01
1.0E+00
1.0E+15
1.0E+14
1.0E+13
1.0E+12
1.0E+11
1.0E+10
1.0E+09
1.0E+08
1.0E+07
1.0E+06
1.0E+05
1.0E+04
1.0E+03
1.0E+02
1.0E+01
1.0E+00214.0H 428.0H 642.0H 856.0H 1070.0H
Resi
stan
ce(O
hm
)
(a)
(b)
Fig. 10 Electrochemical metallic ion migration results : (a) in
-situ measuring results of insulation resistance-te
st time under temperature- humidity-bias test
and (b) Cu ion migration under water drop test6)
Table 1 Test method and conditions for THB test
124 Journal of KWJS, Vol. 25, No. 2, April, 2007
22
1/40ms
. ECM
1106
. PCB
, 100
.
5.
,
.
.
.
PCB
.
(failure criteria)
.
.
.
(RTI04-01-01) ,
.
1. W. Engelmaier, and A. I. Attarwala : Surface Mount
Attachment Reliability of Clip-Leaded Ceramic Chip Carriers
on FR-4 Circuit Boards, IEEE Transaction CHMT, 12-2
(1989), 284-296
2. JEDEC Solid State Technology Association : JESD22-A104
Rev.B, Temperature cycling, JC-14.1 Committee on
Reliability Test methods for Packaged Devices JEDEC,
Arlington, VA (2000)
3. D. A. Jones : Principles and Prevention of Corrosion, p.74,
Macmillan Pub. Company, New York (1992)
4. W. S. Hong and K. B. Kim : Tafel Characteristics by
Electrochemical Reaction of SnAgCu Pb-Free Solder, Korean
Journal of Materials Research, 15-8 (2005), 536-542 (in
Korean)
5. W. S. Hong, W. S. Kim, S. H. Park and K. B. Kim :
Polarization Behaviors of SnCu Pb-Free Solder Depending
on the P, Ni, Addition, Korean Journal of Materials Research,
15-8 (2005), 528-535 (in Korean)
6. W. S. Hong, S. B. Jung and K. B. Kim : Analysis Method
of Metallic Ion Migration, Journal of KWS, 23-2 (2005),
138-146 (in Korean)
7. J. E. Sohn : IPC-TR-476A Electrochemical Migration:
Electrically Induced Failure in Printed Wiring Assemblies,
Electrical Migration Task Group of IPC, IL (1997)
8. Y. Aoki, H. Tanaka, S. Yamamoto and O. Obata : Evaluation
Method for Ion Migration Using Dew Cycle Test(Part 1),
Espec Tech. Report, 1 (1996), 16~22
9. Y. Aoki, H. Tanaka, S. Yamamoto and O. Obata :
Evaluation Method for Ion Migration Using Dew Cycle
Test(Part 2), Espec Tech. Report, 1 (1996), 23-27
10. J. H. Lau, and Y. H. Pao : Solder Joint Reliability of BGA,
CSP, Flip Chip and Fine Pitch SMT Assemblies,
McGraw-Hill, New York (1997)
11. R. Ghaffarian, and W. Engelmaier et al, The Institute for
Interconnecting and Packaging Electronic Circuit : IPC 9701
Performance Test Methods and QuaIification Requirements
for Surface Mount Solder Attachments, the SMT
Attachment Reliability Test Methods Task Group(6-10d) of
the Product and Reliability Committee (6-10) of IPC,
Northbrook IL (2002)
()
1968
, ,
e-mail : [email protected]
()
1976
, ,
e-mail : [email protected]
()
1975
, ,
e-mail : [email protected]
25 2, 2007 4 125
23
()
1958
e-mail : [email protected]
()
1959
, ,
e-mail : [email protected]
1. 2. 3. 4. 5.