Microelectronics packaging technology has evolved from through-hole and bulk configurations to surface-mount and small-profile configurations. Surface mount devices, such as flip chip packages, chip scale packages, and ball grid arrays, use solder bump interconnections between them and substrates/printed wiring boards. Solder bumps, which are hidden between the device and the substrate/board, are difficult to inspect. A solder bump inspection system was developed using laser ultrasound and interferometric techniques. This system has been successfully applied to detect solder joint/bump defects, including missing, misaligned, open, and cracked solder joints/bumps in flip chips, chip scale packages, and multilayer ceramic capacitors. This system uses a pulsed Nd:YAG laser to induce ultrasound in the electronic packages in the thermoelastic regime; it then measures the transient out-of-plane displacement response on the package surface using the interferometric technique. This paper presents a local temporal coherence (LTC) analysis of laser ultrasound signals and compares it to previous signal-processing methods, including error ratio and correlation coefficient methods. The results showed that LTC analysis increased measurement accuracy and sensitivity for inspecting solder bump defects in electronic packages. Laser ultrasound inspection results are also compared with X-ray and C-mode scanning acoustic microscopy results. In particular, this paper discusses defect detection for 6.35×6.35×0.6mm3 flip chips and flip chips (“SiMAF;” Siemens AG) with lead-free solder bumps.

1.
Oresjo
,
S.
, 2002, “
New Study Reveals Component Defect Levels
,”
Circuits Assembly
, May, pp.
39
43
.
2.
Semmens
,
J. E.
, 2000, “
Flip Chips and Acoustic Micro Imaging: An Overview of Past Applications, Present Status, and Roadmap for the Future
,”
Microelectron. Reliab.
0026-2714,
40
(
8–10
), pp.
1539
1543
.
3.
Wright
,
S.
, 2001, “
X-Ray Inspection of IC Packages and PWBs
,”
Chip Scale Rev.
,
5
.
4.
Liu
,
S.
,
Erdahl
,
D.
, and
Ume
,
C.
, 2001, “
A Novel Approach for Flip Chip Solder Joint Quality Inspection: Laser Ultrasound and Interferometer System
,”
IEEE Trans. Compon. Packag. Technol.
1521-3331,
24
(
4
), pp.
616
624
.
5.
Martin
,
P.
, 1999,
Electronic Failure Analysis Handbook
,
McGraw-Hill
,
New York
, pp.
13.26
13.28
.
6.
Moore
,
T. D.
,
Vanderstraeten
,
D.
, and
Forssell
,
P. M.
, 2002, “
Three-Dimensional X-Ray Laminography as a Tool for Detection and Characterization of BGA Package Defects
,”
IEEE Trans. Compon. Packag. Technol.
1521-3331,
25
(
2
), pp.
224
229
.
7.
Zhang
,
L.
,
Ume
,
C.
,
Gamalski
,
J.
, and
Galuschki
,
K.
, 2006, “
Detection of Flip Chip Solder Joint Cracks Using Correlation Coefficient and Auto-Comparison Analyses of Laser Ultrasound Signals
,”
IEEE Trans. Compon. Packag. Technol.
,
1
(
3
), pp.
1
7
. 1521-3331
8.
Liu
,
S.
, and
Ume
,
C.
, 2002, “
Vibration Analysis Based Modeling and Defect Recognition for Flip Chip Solder Joint Inspection
,”
ASME J. Electron. Packag.
1043-7398,
124
, pp.
221
226
.
9.
Liu
,
S.
, and
Ume
,
C.
, 2003, “
Digital Signal Processing in a Novel Flip Chip Solder Joint Defects Inspection System
,”
ASME J. Electron. Packag.
1043-7398,
125
, pp.
39
43
.
10.
Liu
,
S.
, and
Ume
,
C.
, 2002, “
Defects Pattern Recognition for Flip Chip Solder Joint Quality Inspection
,”
Proceedings of the 52nd Electronic Components and Technology Conference (ECTC)
, San Diego, CA, May 28–31.
11.
Yang
,
J.
, and
Ume
,
I. C.
, 2008, “
Thermomechanical Reliability Study of Flip-Chip Solder Bumps: Using Laser Ultrasound Technique and Finite Element Method
,”
58th ECTC
, Orlando, FL, May 27–30.
12.
Michaels
,
J. E.
, and
Michaels
,
T. E.
, 2005, “
Detection of Structural Damage From the Local Temporal Coherence of Diffuse Ultrasonic Signals
,”
IEEE Trans. Ultrason. Ferroelectr. Freq. Control
0885-3010,
52
(
10
), pp.
1769
1773
.
13.
Dather
,
K.
,
Gindre
,
M.
,
Huerou
,
J. -Y.
,
Beenacer
,
R.
, and
Beji
,
H.
, 1997, “
Short Time Correlation Analysis in Porous Medium
,”
1997 IEEE Ultrasonics Symposium
, pp.
819
822
.
14.
Bennacer
,
R.
,
Gindre
,
N.
,
Huerou
,
J. -Y.
, and
Serfaty
,
S.
, 1998, “
Validation of the Shot Time Correlation Analysis
,”
1998 IEEE Ultrasonics Symposium
, pp.
881
884
.
15.
Lubinski
,
M.
,
Emelianov
,
S.
, and
O’Donnell
,
M.
, 1999, “
Speckle Tracking Methods for Ultrasonic Elasticity Imaging Using Short-Time Correlation
,”
IEEE Trans. Ultrason. Ferroelectr. Freq. Control
0885-3010,
46
(
1
), pp.
82
96
.
16.
Stark
,
H.
, and
Woods
,
J.
, 2001,
Probability and Random Processes With Applications to Signal Processing
,
3rd ed.
,
Prentice-Hall
,
Englewood Cliffs, NJ
.
17.
Erdahl
,
D. S.
, and
Ume
,
C.
, 2005, “
Determination of Measurement Limit for Open Solder Bumps on a Flip-Chip Package Using a Laser Ultrasound Inspection System
,”
IEEE Trans. Compon. Packag. Technol.
,
99
, pp.
1
8
. 1521-3331
19.
Chan
,
Y. C.
,
Hung
,
K. C.
, and
Dai
,
X.
, 2000, “
Nondestructive Defect Detection in Multilayer Ceramic Capacitors Using an Improved Digital Speckle Correlation Method With Wavelet Packet Noise Reduction Processing
,”
IEEE Trans. Adv. Packag.
1521-3323,
23
(
1
), pp.
80
87
.
You do not currently have access to this content.