Dominant factors of electromigration (EM) resistance of electroplated copper thin-film interconnections were investigated from the viewpoint of temperature and crystallinity of the interconnection. The EM test under the constant current density of 7 mA/cm2 was performed to observe the degradation such as accumulation of copper atoms and voids. Formation of voids and the accumulation occurred along grain boundaries during the EM test, and finally the interconnection was fractured at the not cathode side but at the center part of the interconnection. From the monitoring of temperature of the interconnection by using thermography during the EM test, this abnormal fracture was caused by large Joule heating of itself under high current density. In order to investigate the effect of grain boundaries on the degradation by EM, the crystallinity of grain boundaries in the interconnection was evaluated by using image quality (IQ) value obtained from electron backscatter diffraction (EBSD) analysis. The crystallinity of grain boundaries before the EM test had wide distribution, and the grain boundaries damaged under the EM loading mainly were random grain boundaries with low crystallinity. Thus, high density of Joule heating and high-speed diffusion of copper atoms along low crystallinity grain boundaries accelerated the EM degradation of the interconnection. The change of Joule heating density and activation energy for the EM damage were evaluated by using the interconnection annealed at 400 °C for 3 h. The annealing of the interconnection increased not only average grain size but also crystallinity of grains and grain boundaries drastically. The average IQ value of the interconnection was increased from 4100 to 6200 by the annealing. The improvement of the crystallinity decreased the maximum temperature of the interconnection during the EM test and increased the activation energy from 0.72 eV to 1.07 eV. The estimated lifetime of interconnections is increased about 100 times by these changes. Since the atomic diffusion is accelerated by not only the current density but also temperature and low crystallinity grain boundaries, the lifetime of the interconnections under EM loading is a strong function of their crystallinity. Therefore, it is necessary to evaluate and control the crystallinity of interconnections quantitatively using IQ value to assure their long-term reliability.

References

References
1.
Alam
,
M. T.
,
Pulavarthy
,
R. A.
,
Bielefeld
,
J.
,
King
,
S. W.
, and
Haque
,
M. A.
,
2014
, “
Thermal Conductivity Measurement of Low-k Dielectric Films: Effect of Porosity and Density
,”
J. Electron. Mater.
,
43
(
3
), pp.
746
754
.
2.
Hu
,
C.
,
Morgen
,
M.
,
Jain
,
P. S. H.
,
Gill
,
W. N.
,
Plawsky
,
J. L.
, and
Wayner
,
P. C.
, Jr.
,
2000
, “
Thermal Conductivity Study of Porous Low-k Dielectric Materials
,”
Appl. Phys. Lett.
,
77
(
1
), pp.
145
147
.
3.
Tu
,
K. N.
,
2011
, “
Reliability Challenges in 3D IC Packaging Technology
,”
Microelectron. Reliab.
,
51
(
3
), pp.
517
523
.
4.
Li
,
M.
, and
Tu
,
K. N.
,
2016
, “
Electromigration Induced Thermomigration in Microbumps by Thermal Cross-Talk Across Neighboring Chips in 2.5D IC
,” IEEE International Reliability Physics Symposium (
IRPS
), Pasadena, CA, Apr. 17–21, pp.
PA.3.1
PA.3.4
.
5.
Li
,
B.
,
Sullivan
,
T. D.
,
Lee
,
T. C.
, and
Badami
,
D.
,
2004
, “
Reliability Challenges for Copper Interconnects
,”
Microelectron. Reliab.
,
44
(
3
), pp.
365
380
.
6.
Shingubara
,
S.
,
Nakasaki
,
Y.
, and
Kaneko
,
H.
,
1991
, “
Electromigration in a Single Crystalline Submicron Width Aluminum Interconnection
,”
Appl. Phys. Lett.
,
58
(
42
), pp.
42
44
.
7.
Wang
,
Y. S.
,
Lee
,
W. H.
,
Chang
,
S. C.
,
Nian
,
J. N.
, and
Wang
,
Y. L.
,
2013
, “
An Electroplating Method for Copper Plane Twin Boundary Manufacturing
,”
Thin Solid Films
,
544
, pp.
157
161
.
8.
Saito
,
N.
,
Murata
,
N.
,
Tamakawa
,
K.
,
Suzuki
,
K.
, and
Miura
,
H.
,
2012
, “
Evaluation of the Crystallinity of Grain Boundaries of Electronic Copper Thin Films for Highly Reliable Interconnections
,” IEEE 62nd Electronic Components and Technology Conference (
ECTC
), San Diego, CA, May 29–June 1, Vol.
173
, pp.
1153
1158
.
9.
Miura
,
H.
,
Suzuki
,
K.
, and
Tamakawa
,
K.
,
2007
, “
Fluctuation Mechanism of Mechanical Properties of Electroplated-Copper Thin Films Used for Three Dimensional Electronic Modules
,”
Key Eng. Mater.
,
353–358
, pp.
2954
2957
.
10.
Timalsina
,
Y. P.
,
Horning
,
A.
,
Spivey
,
R. F.
,
Lewis
,
K. M.
,
Kuan
,
T.
,
Wang
,
G.
, and
Lu
,
T.
,
2015
, “
Effects of Nanoscale Surface Roughness on the Resistivity of Ultrathin Epitaxial Copper Films
,”
Nanotechnology
,
26
(
7
), pp.
1
10
.
11.
Hu
,
C.-K.
,
Rosenberg
,
R.
, and
Lee
,
K. Y.
,
1999
, “
Electromigration Path in Cu Thin-Film Lines
,”
Appl. Phys. Lett.
,
74
(
20
), pp.
2945
2947
.
12.
Lane
,
M. W.
,
Liniger
,
E. G.
, and
Lloyd
,
J. R.
,
2003
, “
Relationship Between Interfacial Adhesion and Electromigration in Cu Metallization
,”
J. Appl. Phys.
,
93
(
3
), pp.
1417
1421
.
13.
Hau-Riege
,
C. S.
, and
Thompsona
,
C. V.
,
2001
, “
Electromigration in Cu Interconnects With Very Different Grain Structures
,”
Appl. Phys. Lett.
,
78
(
22
), pp.
3451
3453
.
14.
Hu
,
C.-K.
,
Gignac
,
L. G.
,
Ohm
,
J.
,
Breslin
,
C. M.
,
Huang
,
E.
,
Bonilla
,
G.
,
Liniger
,
E.
,
Rosenberg
,
R.
,
Choi
,
S.
, and
Simon
,
A. H.
,
2014
, “
Microstructure, Impurity and Metal Cap Effects on Cu Electromigration
,”
AIP Conf. Proc.
,
1601
(
67
), pp.
67
78
.
15.
Galand
,
R.
,
Brunetti
,
G.
,
Arnaud
,
L.
,
Rouvière
,
J.-L.
,
Clément
,
L.
,
Waltz
,
P.
, and
Wouters
,
Y.
,
2013
, “
Microstructural Void Environment Characterization by Electron Imaging in 45 nm Technology Node to Link Electromigration and Copper Microstructure
,”
Microelectron. Eng.
,
106
, pp.
168
171
.
16.
Lin
,
M.-H.
, and
Oates
,
A. S.
,
2011
, “
The Effects of Al Doping and Metallic-Cap Layers on Electromigration Transport Mechanisms in Copper Nanowires
,”
IEEE Trans. Device Mater. Reliab.
,
11
(
4
), pp.
540
547
.
17.
Murata
,
N.
,
Saito
,
N.
,
Tamakawa
,
K.
,
Suzuki
,
K.
, and
Miura
,
H.
,
2015
, “
Effect of Crystallographic Quality of Grain Boundaries on Both Mechanical and Electrical Properties of Electroplated Copper Thin Film Interconnections
,”
ASME J. Electron. Packag.
,
137
(
3
), p.
031001
.
18.
Suzuki
,
K.
,
Murata
,
N.
,
Saito
,
N.
,
Furuya
,
R.
,
Asai
,
O.
, and
Miura
,
H.
,
2013
, “
Improvement of Crystallographic Quality of Electroplated Copper Thin-Film Interconnections for Through-Silicon Vias
,”
Jpn. J. Appl. Phys.
,
52
(
4s
), p.
04CB01
.
19.
Sasagawa
,
K.
,
Hasegawa
,
M.
,
Saka
,
M.
, and
Abé
,
H.
,
2002
, “
Prediction of Electromigration Failure in Passivated Polycrystalline Line
,”
J. Appl. Phys.
,
91
(
11
), pp.
9005
9014
.
20.
Tu
,
K. N.
,
Yeh
,
C. C.
,
Liu
,
C. Y.
, and
Chen
,
C.
,
2000
, “
Effect of Current Crowding on Vacancy Diffusion and Void Formation in Electromigration
,”
Appl. Phys. Lett.
,
76
(
8
), pp.
988
990
.
21.
Choi
,
Z.-S.
,
Mönig
,
R.
, and
Thompson
,
C. V.
,
2007
, “
Activation Energy and Prefactor for Surface Electromigration and Void Drift in Cu Interconnects
,”
J. Appl. Phys.
,
102
(
8
), p.
083509
.
22.
Frankovic
,
R.
, and
Bernstein
,
G. H.
,
1996
, “
Electromigration Drift and Threshold in Cu Thin-Film Interconnects
,”
IEEE Trans. Electron Devices
,
43
(
12
), pp.
2233
2239
.
23.
Huang
,
Y.-T.
,
Huang
,
C.-W.
,
Chen
,
J.-Y.
,
Ting
,
Y.-H.
,
Cheng
,
S.-L.
,
Liao
,
C.-N.
, and
Wu
,
W.-W.
,
2016
, “
Mass Transport Phenomena in Copper Nanowires at High Current Density
,”
Nano Res.
,
9
(
4
), pp.
1071
1078
.
24.
Black
,
J. R.
,
1969
, “
Electromigration—A Brief Survey and Some Recent Results
,”
IEEE Trans. Electron Devices
,
16
(
4
), pp.
338
347
.
25.
Lloyd
,
J. R.
,
Clemens
,
J.
, and
Snede
,
R.
,
1999
, “
Copper Metallization Reliability
,”
Microelectron. Reliab.
,
39
(
11
), pp.
1595
1602
.
26.
Fan
,
C.
,
Asai
,
O.
,
Suzuki
,
K.
, and
Miura
,
H.
,
2013
, “
Effect of the Lattice Mismatch Between Copper Thin-Film Interconnection and Base Material on the Crystallinity of the Interconnection
,” 14th International Conference on Electronic Materials and Packaging (
EMAP
), Lantau Island, Hong Kong, Dec. 13–16, Paper No. 2013-73147.
27.
Asai
,
O.
,
Murata
,
N.
,
Suzuki
,
K.
, and
Miura
,
H.
,
2013
Improvement of the Reliability of Thin-Film Interconnections Based on the Control of the Crystallinity of the Thin Films
,” 14th International Conference on Electronic Materials and Packaging (
EMAP
), Lantau Island, Hong Kong, Dec. 13–16, Paper No. 2013-73149.
28.
Murata
,
N.
,
Suzuki
,
K.
, and
Miura
,
H.
,
2012
, “
Quantitative Evaluation of the Crystallinity of Grain Boundaries in Polycrystalline Materials
,”
ASME
Paper No. IMECE2012-87426.
29.
Besser
,
P.
,
Marathe
,
A.
,
Zhao
,
L.
,
Herrick
,
M.
,
Capasso
,
C.
, and
Kawasaki
,
H.
,
2000
, “
Optimizing the Electromigration Performance of Copper Interconnects
,” International Electron Devices Meeting (
IEDM
), San Francisco, CA, Dec. 10–13, pp.
119
122
.
30.
Yang
,
C.-C.
,
Li
,
B.
,
Baumann
,
F. H.
,
Li
,
J.
,
Edelstein
,
D.
, and
Rosenberg
,
R.
,
2014
, “
Microstructure Modulation in Copper Interconnects
,”
IEEE Electron Device Lett.
,
35
(
5
), pp.
572
574
.
31.
Jia
,
Y.
,
Zhonga
,
T.
,
Lia
,
Z.
,
Wanga
,
X.
,
Luoa
,
D.
,
Xiab
,
Y.
, and
Liua
,
Z.
,
2004
, “
Grain Structure and Crystallographic Orientation in Cu Damascene Lines
,”
Microelectron. Eng.
,
71
(
2
), pp.
182
189
.
32.
Nitta
,
T.
,
Ohmi
,
T.
,
Hoshi
,
T.
,
Sakai
,
S.
,
Sakaibara
,
K.
,
Imai
,
S.
, and
Shibata
,
T.
,
1993
, “
Evaluating the Large Electromigration Resistance of Copper Interconnects Employing a Newly Developed Accelerated Life‐Test Method
,”
J. Electrochem. Soc.
,
140
(
4
), pp.
1131
1137
.
33.
Frank
,
T.
,
Moreau
,
S.
,
Chappaz
,
C.
,
Leduc
,
P.
,
Arnaud
,
L.
,
Thuaire
,
A.
,
Chery
,
E.
,
Lorut
,
F.
,
Anghel
,
L.
, and
Poupon
,
G.
,
2013
, “
Reliability of TSV Interconnects: Electromigration, Thermal Cycling, and Impact on Above Metal Level Dielectric
,”
Microelectron. Reliab.
,
53
(
1
), pp.
17
19
.
34.
Miyajima
,
Y.
,
Aragaki
,
T.
,
Adachi
,
H.
,
Fujii
,
T.
,
Onaka
,
S.
, and
Kato
,
M.
,
2012
, “
Retardation of Softening of Ultrafine-Grained Copper During Low Temperature Annealing Under Uniaxial Tensile Stress
,”
Mater. Trans.
,
53
(
1
), pp.
96
100
.
35.
Lloyd
,
J. R.
, and
Clement
,
J. J.
,
1995
, “
Electromigration in Copper Conductors
,”
Thin Solid Films
,
262
(
1–2
), pp.
135
141
.
You do not currently have access to this content.