-
8/11/2019 Intermetalic Compound
1/31
1
InterfacialReactionsandIntermetallicCompoundsinSolderJoints
Peng Sun,Ph.D.CandidateSMITCenter,DepartmentofMicrotechnology
andNanoscience
ChalmersUniversityofTechnology&
SinoSwedishMicrosystemIntegrationTechnology(SMIT)Center,ShanghaiUniversity
[email protected]
-
8/11/2019 Intermetalic Compound
2/31
2
Solders
in
electronic
packaging
and
assembly
-
8/11/2019 Intermetalic Compound
3/31
3
Solderjointinterconnectioniscompletedbytheformationofintermetallic
compounds(IMC)attheinterfacebetweenthesolderandsubstratemetallization.
Athin,continuousanduniformIMClayerisanessentialrequirementforgoodbonding.AthickIMClayerissensitivetostressandsometimesprovidessitesfortheinitiationandpropagationofcracks.
Arelativelywellestablishedknowledgebasedonphysical,metallurgicalandreliabilityissuesofleadfreesoldersisstillinconstruction,whichwasveryimportantforthereliabilityofelectronicproducts.
Background
on
intermetallic
compounds
-
8/11/2019 Intermetalic Compound
4/31
4
BinarySnCu BinarySnNi
Phase
diagram
in
common
use
-
8/11/2019 Intermetalic Compound
5/31
5
1: Cu6Sn5
2:Cu3Sn
Cu6Sn5&
Cu3Sn
in
Sn
Ag
Cu
joint
12
-
8/11/2019 Intermetalic Compound
6/31
6
Cu6Sn5on
fracture
surface
in
Sn
Ag
Cu
-
8/11/2019 Intermetalic Compound
7/31
7
Sn
Cu
Cu6Sn5&
Cu3Sn
on
fracture
surface
-
8/11/2019 Intermetalic Compound
8/31
8
Sn37Pb,Ni3Sn4
Sn36Pb2Ag,Ni3Sn4
Sn
Pb/Sn
Pb
Ag soldering
on
Ni
-
8/11/2019 Intermetalic Compound
9/31
9
Sn-3.5Ag,Ni3Sn4
Sn-0.7Cu,(Cu,Ni)6Sn5
Sn
Ag/Sn
Cu soldering
on
Ni
-
8/11/2019 Intermetalic Compound
10/31
10
Sn-4.0Ag-0.5Cu,Ag3Sn &(Cu,Ni)6Sn5
Sn-3.8Ag-0.7Cu,Ag3Sn &(Cu,Ni)6Sn5
Sn
Ag
Cu
soldering
on
Ni
-
8/11/2019 Intermetalic Compound
11/31
11
Sn-9Zn,Ni-Zn
Sn-8Zn-3Bi,Ni-Zn
Sn
Zn/Sn
Zn
Bi soldering
on
Ni
-
8/11/2019 Intermetalic Compound
12/31
12
Sn-0.7Cu, Cu6Sn5
Sn-3.5Ag, Ag3Sn Sn-4.0Ag-0.5Cu, Ag3Sn, Cu6Sn5
IMCs in
the
solder
matrix
-
8/11/2019 Intermetalic Compound
13/31
13
Ag3Sn
in
Sn
3.8Ag
0.7Cu
solder
joint
-
8/11/2019 Intermetalic Compound
14/31
14
Eutectic
point
in
Sn
Co
Cu
system
-
8/11/2019 Intermetalic Compound
15/31
15
Soldermatrix
Interface
IMCs in
Sn
Co
Cu
solder
joint
CoSn2Cu6Sn5
(Cu,Ni)6
Sn5
-
8/11/2019 Intermetalic Compound
16/31
16
Solder,IMCs inthematrix,IMCs onCusubstrate,IMCs
onNisubstrate
SnPb No Cu6Sn5 Ni3Sn4
SnPbAg Ag3Sn Cu6Sn5 Ni3Sn4SnAg Ag3Sn Cu6Sn5 Ni3Sn4SnAgBi Ag3Sn
Cu6Sn5 Ni3Sn4
SnAgCu Ag3Sn,Cu6Sn5 Cu6Sn5 (Cu,Ni)6Sn5,(Ni,Cu)3Sn4SnCu Cu6Sn5
Cu6Sn5 (Cu,Ni)6Sn5SnCoCu Cu6Sn5,CoSn2 Cu6Sn5 (Cu,Ni)6Sn5SnZn No
Cu5Zn8 Ni5Sn21SnZnBi No Cu5Zn8 Ni5Sn21
DependedontheCucontentinthesolderalloy.
Conclusion
-
8/11/2019 Intermetalic Compound
17/31
17
Aging
Aging
Sn3.5Ag
Sn4.0Ag0.5Cu
Afterhightemperaturestorage(HTS)
-
8/11/2019 Intermetalic Compound
18/31
18
1
2
3
4
crystalsinNiPphase
TEMobservationinSnAgCujoint
1:Ni3Sn42:Prich
3:Ni(P)
4:Cu
-
8/11/2019 Intermetalic Compound
19/31
19Eutectic
Sn
Pb solder
joint
after
thermal
cycling
(TC)
test
flux
CoarseninSn37Pbjoints
-
8/11/2019 Intermetalic Compound
20/31
20Ag3SnevolutioninLFSnAgCuPBGAsolderjointduringTC
CoarseninSn3.8Ag0.7Cusolderjoints
-
8/11/2019 Intermetalic Compound
21/31
21Sn3.8Ag0.7CuPBGAsolderjointafter6000cycles
IMCs andcrack,componentside
-
8/11/2019 Intermetalic Compound
22/31
22Sn3.8Ag0.7CuPBGAsolderjointafter6000cycles
IMCs andcrack,PCBside
-
8/11/2019 Intermetalic Compound
23/31
23
CBGATC,SungK.Kang,IBMT.J.WatsonResearchCenter
Drop
test,
Jorma Kivilahti,
Helsinki
University
of
Technology
Discussionfracturemode
-
8/11/2019 Intermetalic Compound
24/31
24
Couplingbetweenoppositesubstrates
-
8/11/2019 Intermetalic Compound
25/31
25Interfacialproductevolutionduringprolongedreflow
CouplinginSnAgBisolderjoint1min 5min
10min 20min 60min
-
8/11/2019 Intermetalic Compound
26/31
26
AnalysisresultsoftheSnNiCuinterfacialIMCs
(Cu+Ni):Sn=57:43,(Cu,Ni)6Sn5
-
8/11/2019 Intermetalic Compound
27/31
27
At
N
MfATJ
Cu
Cu
= 01
tM
NfTJ
Cu
Cu
= 0
x
CCDJ 21
=
TheCuatomicfluxfromtheCusubstratetotheNi(P)metallizationlayercouldbecalculatedbythefollowingexpression:
Tistheintermetallic compoundthickness,3.1
m
Aisthepadareaofsoldering
isthedensityofCu6Sn5phase,8.27g/cm3,
fCuistheCuweightfractioninCu6Sn5,0.39
MCuis
the
molecular
weight
of
Cu,
63.5gN0istheAvogadrosnumber,6.0210
23
trepresentsthereflowtime,60s
CudiffusioninSnAgBisolderjoint
D=1.1105cm2/s
-
8/11/2019 Intermetalic Compound
28/31
28
Cu/Niside
Cuside
After60minreflowat240oC
CouplinginSnZnBisolderjoint
-
8/11/2019 Intermetalic Compound
29/31
29
CouplinginSnZnBisolderjoint
Sn3.5Ag3Bi/Ni,3.80
1010cm2/s;Sn8Zn3Bi/Ni,2.93
1012cm2/s
Sn3.5Ag3Bi/Cu,1.441010cm2/s;Sn8Zn3Bi/Cu,1.361010cm2/s
-
8/11/2019 Intermetalic Compound
30/31
30
SixthEUproject,FlexEman
(Flexiblesolderingcellsforagileelectronicsmanufacture)underthecontractNo:COOPCT2003507983
Appreciation is extended to the Shanghai Science
andTechnologyCommission,ChinaunderresearchcontractsNo:045107006and035007031.
Financial support provided by the SMITCenter membercompanies
including Avantec, France; Flextronics, HellerIndustries, USA;
ToyoKohan, Sumitomo Chemicals andHitachiChemicals,Japan;Nera
andConpart,Norway;MydataAutomation, Note, Svensk optoelektronik,
ngstrmsAerospaceCoandFoab Elektronik,Sweden.
Acknowledgement
-
8/11/2019 Intermetalic Compound
31/31
31
Thanksforyourattention!
May
24,
2007
