Application of the moire interferometry to thermal strain analysis for electronics packaging

2003 ◽  
Author(s):  
Zhaowei Zhong
Keyword(s):  
Thermal Strain ◽  
Strain Analysis ◽  
Electronics Packaging ◽  
Moiré Interferometry ◽  
Moire Interferometry

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.

Moiré strain analysis: An introduction, review and critique, including related techniques and future potential

1998 ◽  
Vol 33 (2) ◽  
pp. 137-151 ◽  
Author(s):  
J McKelvie
Keyword(s):  
Recent Work ◽  
Strain Analysis ◽  
Moiré Interferometry ◽  
Moire Interferometry ◽  
Future Developments ◽  
Moire Fringe ◽  
Future Potential ◽  
The Common ◽  
Moiré Fringe ◽  
Preparation Techniques

The moire fringe method is described and reviewed with particular reference to its application in strain analysis. The theory is briefly dealt with, followed by a discussion of the common methods used to analyse the information that the fringes contain and then certain non-obvious limitations are discussed. The generic grid-preparation techniques and optical arrangements are described. Moire interferometry is dealt with at some greater length, and questions that are frequently raised concerning moire in comparison to somewhat similar methods are addressed. Specific difficulties are indicated and the work concludes with a consideration of some recent work that may influence future developments of the method. Of necessity, there is much reliance on reference to quoted works.

Microstructural strain analysis by high-magnification moire interferometry

1995 ◽  
Author(s):  
Jonathan M. Huntley ◽  
S. J. P. Palmer ◽  
Howell T. Goldrein ◽  
L. Gunnar Melin
Keyword(s):  
Strain Analysis ◽  
Moiré Interferometry ◽  
Moire Interferometry ◽  
High Magnification

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.

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.

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