Five halogen-free (HF) dummy plastic ball grid array (PBGA) components with daisy-chains and Sn4.0Ag0.5Cu (SAC405) Pb-free solder balls were assembled on a HF high density interconnection (HDI) printed circuit board (PCB) using Sn1.0Ag0.5Cu (SAC105) and Sn3.0Ag0.5Cu (SAC305) Pb-free solder pastes, respectively. The above compositions were in weight percent. The assemblies were then experienced to moisture sensitive level testing with three times reflow at a peak temperature of 260 °C; no delamination was found present in both the component and PCB laminates. The microstructure showed that the utilization of SAC105 solder paste was beneficial in refining the Ag3Sn intermetallic compound (IMC) within the solder joint and the intermetallic layers formed at various interfaces with different Ni contents and thicknesses due to different metal finishes. The IMC spalling was found at the BGA-side interface within the solder joints formed with SAC105 solder paste but not discovered within the ones made of SAC305 solder paste. The pull strength of the solder joint formed with SAC305 solder paste was always higher than that made from SAC105 no matter on Cu or electroless Ni. Moreover, the fracture was found at the interface between the Cu foil and epoxy in the halogen-free test device. Numerical analysis showed that the thickness of IMC layer dominated the pull strength of the solder joint because the Z-axial normal stress applied to the solder joints formed with Cu and electroless Ni were 752.0 and 816.6 MPa, respectively, and a thicker IMC layer was beneficial to provide a higher pull strength of solder joint.

References

References
1.
Norwegian Pollution Control Authority
, 2007,
Impact Assessment of a Proposal for Prohibition on Certain Hazardous Substances in Consumer Products
,
Norwegian Pollution Control Authority
,
Norway
, pp.
1
50
.
2.
Yu
,
C. K.
,
Chang
,
G.
,
Shao
,
T.
,
Chen
,
C.
, and
Lee
,
J.
, 2009, “
The Impact Investigation of CSP IC Packaging on Halogen-Free Board-Level Performance
,”
Proceedings of International Microsystems, Packaging, Assembly and Circuit Technology Conference
, pp.
666
669
.
3.
Jonnalagadda
,
K.
,
Qi
,
F.
, and
Liu
,
J.
, 2005, “
Mechanical Bend Fatigue Reliability of Lead-Free and Halogen-Free PBGA Assemblies
,”
IEEE Trans. Compon. Packag. Technol
,
28
(
3
), pp.
430
434
.
4.
Renavikar
,
M. P.
,
Patel
,
N.
,
Dani
,
A.
,
Wakharkar
,
V.
,
Arrigotti
,
G.
,
Vasudevan
,
V.
,
Bchir
,
O.
,
Alur
,
A. P.
,
Gurumurthy
,
C. K.
, and
Stage
,
R. W.
, 2008, “
Materials Technology for Environmentally Green Micro-Electronic Packaging
,”
Intel Technol. J.
,
12
(
1
), pp.
1
14
.
5.
Lin
,
T. Y.
,
Pecht
,
M. G.
,
Das
,
D.
, and
Teo
,
K. C.
, 2006, “
The Influence of Substrate Enhancement on Moisture Sensitive Level (MSL) Performance for Green PBGA Packages
,”
IEEE Trans. Compon. Packag. Technol.
,
29
(
3
), pp.
522
527
.
6.
Xie
,
D.
,
Wang
,
J.
,
Yu
,
H.
,
Lau
,
D.
, and
Shangguan
,
D.
, 2007, “
Impact Performance of Microvia and Buildup Layer Materials and Its Contribution to Drop Test Failures
,”
Proceedings of Electronic Component and Technology Conference
, pp.
391
399
.
7.
IPC, 2004, “
Moisture/Reflow Sensitive Classification for Non-hermetic Solid State Surface Mount Devices
,” IPC/JEDEC J-STD-020C Standard.
8.
Wang
,
T. H.
, and
Lai
,
Y. S.
, 2005, “
Submodeling Analysis for Path-Dependent Thermomechanical Problems
,”
J. Electron. Packag.
,
127
(
2
), pp.
135
140
.
9.
Mey
,
S.
, 1992, “
Thermodynamic Re-Assessment of the Cu-Ni System
,”
CALPHAD: Comput. Coupling Phase Diagrams Thermochem.
,
16
, pp.
255
260
.
10.
Zeng
,
K.
, and
Tu
,
K. N.
, 2002, “
Six cases of Reliability Study of Pb-Free Solder Joints in Electron Packaging Technology
,”
Mater. Sci. Eng. Rep.
,
R38
, pp.
55
105
.
11.
Laurila
,
T.
,
Vuorinen
,
V.
, and
Kivilahti
,
J. K.
, 2005, “
Interfacial Reactions Between Lead-Free Solders and Common Base Materials
,”
Mater. Sci. Eng. Rep.
,
49
, pp.
1
60
.
12.
Choi
,
W. K.
, and
Lee
,
K. M.
, 2000, “
Effect of Soldering and Aging Time on Interfacial Microstructure and Growth of Intermetallic Compounds Between Sn-3.5Ag solder Alloy and Cu Substrate
,”
J. Electron. Mater.
,
29
(
10
), pp.
1207
1213
.
13.
Zhang
,
F.
,
Li
,
M.
,
Chum
,
C. C.
, and
Tu
,
K. N.
, 2002, “
Influence of Substrate Metallization on Diffusion and Reaction at the Under-Bump Metallization/Solder Interface in Flip-Chip Packages
,”
J. Mater. Res.
,
17
(
11
), pp.
2757
2760
.
14.
Ho
,
C. E.
,
Lin
,
Y. W.
,
Yang
,
S. C.
,
Kao
,
C. R.
, and
Jiang
,
D. S.
, 2006, “
Effects of Limited Cu Supply on Soldering Reactions Between SnAgCu and Ni
,”
J. Electron. Mater.
,
35
(
5
), pp.
1017
1024
.
15.
Sharif
,
A.
,
Chan
,
Y. C.
,
Islam
,
M. N.
, and
Rizvi
,
M. J.
, 2005, “
Dissolution of Electroless Ni Metallization by Lead-Free Solder Alloys
,”
J. Alloys Compd.
,
388
(
1
), pp.
75
82
.
16.
Chen
,
W. T.
,
Ho
,
C. E.
, and
Kao
,
C. R.
, 2002, “
Effect of Cu Concentration on the Interfacial Reactions Between Ni and Sn-Cu Solders
,”
J. Mater. Res.
,
17
(
2
), pp.
263
266
.
17.
Ho
,
C. E.
,
Yang
,
S. C.
, and
Kao
,
C. R.
, 2007, “
Interfacial Reaction Issues for Lead-Free Electronic Solders
,”
J. Mater. Sci.: Mater. Electron.
,
18
, pp.
155
174
.
18.
Alonso
,
J. C.
, and
Cubero
,
J. A.
,
Use of Pb-Free Solder Alloys in Electrical and Electronic Devices for the Automotive Industry
,
Applied Research and Technological Department, European Technological Center
,
Spain
.
19.
Chada
,
S.
,
Fournelle
,
R. A.
,
Laub
,
W.
, and
Shangguan
,
D.
, 2000, “
Copper Substrate Dissolution in Eutectic Sn-Ag Solder and Its Effect on Microstructure
,”
J. Electron. Mater.
,
29
(
10
), pp.
1214
1221
.
20.
Yoon
,
J. W.
,
Kim
,
S. W.
, and
Jung
,
S. B.
, 2005, “
IMC Morphology, Interfacial Reaction and Joint Reliability of Pb-Free Sn-Ag-Cu Solder on Electrolytic Ni BGA Substrate
,”
J. Alloys Compd.
,
392
, pp.
247
252
.
21.
Tu
,
K. N.
,
Ku
,
F.
, and
Lee
,
T. Y.
, 2001, “
Morphological Stability of Solder Reaction Products in Flip Chip Technology
,”
J. Electron. Mater.
,
30
(
9
), pp.
1129
1132
.
22.
Hung
,
K. C.
,
Chan
,
Y. C.
,
Tang
,
C. W.
, and
Ong
,
H. C.
, 2000, “
Correlation Between Ni3Sn4 Intermetallics and Ni3P Due to Solder Reaction-Assisted Crystallization of Electroless Ni-P Metallization in Advanced Packages
,”
J. Mater. Res.
,”
15
(
11
), pp.
2534
2539
.
23.
Wang
,
Y. W.
,
Lin
,
Y. W.
, and
Kao
,
C. R.
, 2009, “
Kirkendall Voids Formation in the Reaction Between Ni-Doped SnAg Pb-Free Solder and Different Cu Substrates
,”
Microelectron. Reliab.
,
49
(
3
), pp.
248
252
.
24.
Mattila
,
T.
, and
Kivilahti
,
J.
, 2005, “
Failure Mechanisms of Lead-Free Chip Scale Package Interconnections Under Fast Mechanical Loading
,”
J. Electron. Mater.
,
34
(
7
), pp.
969
976
.
25.
Xu
,
L.
, and
Pang
,
J. H. L.
, 2006, “
Nano-Indentation Characterization of Ni-Cu-Sn IMC Layer Subject to Isothermal Aging
,”
Thin Solid Films
,
504
, pp.
362
366
.
26.
Che
,
F. X.
,
Poh
,
E. C.
,
Zhu
,
W. H.
, and
Xiong
,
B. S.
, 2007, “
Ag Content Effect on Mechanical Properties of Sn-xAg-0.5Cu Solders
,”
Proceedings of Electronics Packaging Technology Conference
, pp.
713
718
.
27.
Zhao
,
X. J.
,
Caers
,
J. F. J. M.
,
dc Vries
,
J. W. C.
,
Wong
,
E. H.
, and
Rajoo
,
R.
, 2007, “
A Component Level Test Method for Evaluating the Resistance of Pb-Free BGA Solder Joints to Brittle Fracture Under Shock Impact
,”
Proceedings of Electronics Packaging Technology Conference
, pp.
1522
1529
.
28.
Suh
,
D.
,
Kim
,
D. W.
,
Liu
,
P.
,
Kim
,
H.
,
Weninger
,
J. A.
,
Kumar
,
C. M.
,
Prasad
,
A.
,
Grimsley
,
B. W.
, and
Tejada
,
H. B.
, 2007, “
Effects of Ag Content on Fracture Resistance of Sn–Ag–Cu Lead-Free Solders Under High-Strain Rate Conditions
,”
Mater. Sci. Eng.
, pp.
595
603
.
29.
Kim
,
K. S.
,
Huh
,
S. H.
, and
Suganuma
,
K.
, 2003, “
Effect of Intermetallic Compounds on Properties of Sn-Ag-Cu Lead-Free Soldered Joints
,”
J. Alloys Compd.
,
352
, pp.
226
236
.
30.
Lu
,
H. Y.
,
Balkan
,
H.
, and
Simon Ng
,
K. Y.
, 2006, “
Effect of Ag Content on the Microstructure Development of Sn-Ag-Cu Interconnects
,”
Mater. Electron.
,
17
, pp.
171
188
.
You do not currently have access to this content.