Thermal Strain Measurements of Solder Joints in Second Level Interconnections Using Moire Interferometry

1992 ◽  
Vol 114 (1) ◽  
pp. 88-92 ◽  
Author(s):  
Yifan Guo ◽  
Charles G. Woychik
Keyword(s):  
Thermal Expansion ◽  
Solder Joints ◽  
Coefficient Of Thermal Expansion ◽  
Low Cycle Fatigue ◽  
Thermal Strain ◽  
Moiré Interferometry ◽  
Moire Interferometry ◽  
Mechanical Reliability ◽  
Surface Mount ◽  
Inherent Strength

Low cycle fatigue of solder joints is one of the major kinds of failures in second level interconnections of an electronic package. The fatigue failure is caused by thermal strains which are created from a mismatch of coefficients of thermal expansion (CTE) that occurs between two levels of packaging. As the package approaches smaller dimensions, measurements of thermal strains in the solder interconnections become very difficult. In this paper, moire interferometry technique was applied to evaluate the thermal strains in the second level interconnections for both conventional pin-in-hole (PIH) packages and surface mount components. The coefficient of thermal expansion of each component was measured. Thermal strain distributions in the solder interconnections were determined, and reliability issues were discussed. The strains in solder joints of the PIH components were much higher than those of the stacked surface mount components. Even though the surface mount components had a lower inherent strength, their overall mechanical reliability was much higher since they had practically no localized strain concentrations.

Real-Time Monitoring and Simulation of Thermal Deformation in Plastic Package

1998 ◽  
Vol 120 (2) ◽  
pp. 160-165 ◽  
Author(s):  
J. Zhu ◽  
D. Zou ◽  
S. Liu
Keyword(s):  
Finite Element ◽  
Thermal Cycling ◽  
Real Time ◽  
Electronic Packaging ◽  
Thermal Deformation ◽  
Moiré Interferometry ◽  
Moire Interferometry ◽  
Plastic Package ◽  
Highly Nonlinear ◽  
Fringe Patterns

Thermally-induced failure is a major reliability issue for electronic packaging. Due to the highly nonlinear behaviors and thermal mismatch of packaging materials, an electronic package exhibits uneven thermal deformation in the whole temperature range during thermal cycling. This behavior will affect the buildup of thermal strain/stress within the package, which may affect the reliability of the package. Therefore, a real-time method is needed to monitor the thermal deformation of packages during the thermal cycling. In this study, a real-time moire´ interferometry technique coupled with a thermal vacuum chamber is used to monitor the thermal deformation of a plastic package. A grating is transferred onto the cross section of the sample at room temperature. The fringe patterns are recorded by a CCD camera system and are compared with the displacement contours obtained by nonlinear finite element simulation. High temperature moire´ results up to 200°C are reported here. The comparison between the moire´ fringe patterns and finite element results shows a good agreement. The results also show that the real-time moire´ interferometry technique is an effective way to monitor the thermal deformation of electronic packaging and is a powerful validation method for finite element analysis.

Moire´ Interferometry Analysis of Laser Weld Induced Thermal Strain

1994 ◽  
Vol 116 (3) ◽  
pp. 177-183 ◽  
Author(s):  
V. T. Kowalski ◽  
A. S. Voloshin
Keyword(s):  
Image Analysis ◽  
Digital Image ◽  
Digital Image Analysis ◽  
Thermal Strain ◽  
Moiré Interferometry ◽  
Second Phase ◽  
Moire Interferometry ◽  
Laser Weld ◽  
Optical Components ◽  
Principal Axes

An experimental method is presented to study laser weld induced thermal strain using digital image analysis enhanced moire´ interferometry. A phenomenon that occurs in the assembly of optical components is that the final optimum coupled power will randomly change upon completion of the laser weld process. The change in power is due to residual thermal stresses being generated in the welded components. For single mode devices, relative motions of the components in the order of 1 μm could result in a 1 dB degradation of coupled power. The behavior of thermal strain is unpredictable since the relative orientation of the optical components at the optimum alignment is random. The goal of this investigation was to perform a baseline study of parameters affecting laser weld thermal strain. The first phase of the work was to study thermal strain induced by a single weld on a flat Kovar plate. The results show that thermal strain is independent of material inhomogeneity. However, this investigation did reveal asymmetry of the power distribution in the weld laser with a principal axes offset +30 deg from horizontal. The second phase of the experiment was to characterize thermal strain resulting from welding on an interface of two Kovar plates. The results indicate that thermal strain at the center of two welds is not affected by welds that are greater than 1 mm apart. Also, thermal strain levels at locations adjacent to the weld are not significantly affected by weld separation distance. This study successfully demonstrated that digital image analysis enhanced moire´ interferometry can be used in the study of laser weld induced thermal strain. Digital image processing, fractional fringe analysis, and high frequency specimen gratings increase sensitivity levels to enable the technique to be used to characterize submicron thermal distortions.

Thermal Deformation Measurement on Electronic Packaging by Moire Interferometry

2000 ◽  
Vol 2000 (0) ◽  
pp. 537-538
Author(s):  
Kazuo ARAKAWA ◽  
Mitsugu TODO ◽  
Shinji YAMADA ◽  
Yashuyuki MORITA ◽  
Kiyoshi TAKAHASHI
Keyword(s):  
Electronic Packaging ◽  
Thermal Deformation ◽  
Moiré Interferometry ◽  
Deformation Measurement ◽  
Moire Interferometry

Damage Mechanics of Solder Joints under High Current Density

2007 ◽  
Vol 345-346 ◽  
pp. 1403-1410
Author(s):  
Cemal Basaran
Keyword(s):  
Damage Mechanics ◽  
Solder Joints ◽  
High Current Density ◽  
Time History ◽  
Moiré Interferometry ◽  
Lead Free ◽  
Moire Interferometry ◽  
Lead Free Solder ◽  
Current Stressing ◽  
Free Solder

In this paper, Moiré interferometry technique is used to measure the in-situ displacement evolution of lead-free solder joints under high density (104A/cm2). An electromigration constitutive model is developed to simulate deformation of lead-free solder joint under current stressing. The simulation predicts Moiré interferometry measurements in both spatial distribution and time history evolution, which indicates that the model is reasonably good for predicting the mechanical behavior of lead-free solder joints under electric current stressing.

Thermal Deformation Analysis of Various Electronic Packaging Products by Moire´ and Microscopic Moire´ Interferometry

1995 ◽  
Vol 117 (3) ◽  
pp. 185-191 ◽  
Author(s):  
B. Han ◽  
Y. Guo
Keyword(s):  
Mechanical Behavior ◽  
Electronic Packaging ◽  
Early Stage ◽  
High Sensitivity ◽  
Moiré Interferometry ◽  
Deformation Analysis ◽  
Moire Interferometry ◽  
Plated Through Hole ◽  
Chip Carrier

Thermo-mechanical behavior of various levels of electronic packaging products is studied by moire´ and microscopic moire´ interferometry. The global deformations of packages with complex geometries and the local deformations of solder interconnections are determined by displacement measurements of high sensitivity and high spatial resolution. Several packaging studies are reviewed. They include analyses of thin small outline package, leadless chip carrier package, surface mount array package, chip/organic carrier package, deformation near a plated through hole, and determination of an effective CTE. In-situ and quantitative nature of the methods leads to more accurate and realistic understanding of the macro and micro mechanical behavior of packaging assemblies and interconnections, which in turn, facilitates design evaluation and optimization at an early stage of product development.

Thermal Strain Measurements in Electronic Packages Through Fractional Fringe Moire´ Interferometry

1990 ◽  
Vol 112 (4) ◽  
pp. 303-308 ◽  
Author(s):  
A. F. Bastawros ◽  
A. S. Voloshin
Keyword(s):  
Mechanical Strain ◽  
Thermal Strain ◽  
Strain Analysis ◽  
Moiré Interferometry ◽  
Experimental Methodology ◽  
Moire Interferometry ◽  
Displacement Fields ◽  
Thermally Induced ◽  
Contour Maps ◽  
Strain Components

Fractional Fringe Moire´ Interferometry (FFMI)—a new experimental methodology to measure accurately deformations and consequently strains—has been successfully implemented to determine thermally induced strains in a specimen made from an AT&T 1MB DRAM device. The specimen was heated uniformly from room temperature to 90° C. Resulting moire´ fringe patterns were recorded, analyzed using digital-image-processing and in plane displacements in the device were determined. Strain components were computed by simple differentiation of the displacement fields. The technique proved to be successful in detecting full displacement fields with submicron resolution. Contour maps showing actual thermo/mechanical strain components in the specimen were constructed. Those maps can provide an excellent tool realistic for strain analysis of microelectronic devices regardless of the structural and material complexity.

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