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.

Moiré interferometry for thermal expansion of composites

1981 ◽  
Vol 21 (12) ◽  
pp. 441-447 ◽  
Author(s):  
D. E. Bowles ◽  
D. Post ◽  
C. T. Herakovich ◽  
D. R. Tenney
Keyword(s):  
Thermal Expansion ◽  
Moiré Interferometry ◽  
Moire Interferometry

Effect of High Glass Transition Temperature on Reliability of Non-Conductive Film (NCF)

2006 ◽  
Vol 326-328 ◽  
pp. 517-520 ◽  
Author(s):  
Jin Hyoung Park ◽  
Chang Kyu Chung ◽  
Kyoung Wook Paik ◽  
Soon Bok Lee
Keyword(s):  
Glass Transition ◽  
Shear Strain ◽  
Flip Chip ◽  
Coefficient Of Thermal Expansion ◽  
Moiré Interferometry ◽  
Moire Interferometry ◽  
Effective Parameters ◽  
Conductive Film ◽  
Interferometry Method ◽  
Stress Free State

Among many factors that influence the reliability of a flip-chip assembly using NCF interconnections, the most effective parameters are often the coefficient of thermal expansion (CTE), the modulus (E), and the glass transition temperatures (Tg). Of these factors, the effect of Tg on thermal deformation and device reliability is significant; however, it has not been shown clearly what effect Tg has on the reliability of NCF. The Tg of a conventional NCF material is approximately 110°C. In this study, a new high Tg NCF material that has a 140oC Tg is proposed. The thermal behaviors of the conventional and new NCFs between -40oC to 150oC are observed using an optical method. Twyman-Green interferometry and the moiré interferometry method are used to measure the thermal micro-deformations. The Twyman-Green interferometry measurement technique is applied to verify the stress-free state. The stress-free temperatures of the conventional and new Tg NCF materials are approximately 100oC and 120oC respectively. A shear strain at a part of the NCF chip edge is measured by moiré interferometry. Additionally, a method to accurately measure the residual warpage and shear strain at room temperature is proposed. Through the analysis of the relationship between the warpage and the shear strain, the effect of the high-Tg NCF material on the reliability is studied.

Microstructural Evaluation and Quantitative Analysis in the Unleaded Solder Joint

1999 ◽  
Vol 5 (S2) ◽  
pp. 602-603
Author(s):  
J.G. Duh ◽  
Y.G. Lee ◽  
F.B. Wu
Keyword(s):  
Thermal Expansion ◽  
Solder Joint ◽  
Solder Joints ◽  
Environmental Concern ◽  
Coefficient Of Thermal Expansion ◽  
Practical Importance ◽  
Thermal Expansion Coefficients ◽  
Free Solder ◽  
Joint Quality ◽  
Microelectronic Package

Solder joints provide mechanical and electronic connections between solders and components for various levels in microelectronic package. However, due to different thermal expansion coefficients and elastic modulus of the associated materials, solder joints are susceptible to fatigue degration, microcracks and fracture. The solder joint reliability is, therefore, critical in the evalution of the joint quality. Recently, the employment of lead-free solder is attractive due to the environmental concern of the Pb-containing solder. Hence, the investigation on the unleaded solder joint is of practical importance in the field of microelectronic package.Intermetallic compounds (IMC), which form and grow between solders and metallizations, are considered to be a source of mechanical weakness for its brittleness and different coefficient of thermal expansion from the metallization or the solder.

Residual Stress Measurement in Spot Welds and the Effect of Fatigue Loading on Redistribution of Stresses Using High Sensitivity Moire´ Interferometry

2000 ◽  
Vol 123 (1) ◽  
pp. 132-138 ◽  
Author(s):  
Sanjeev K. Khanna ◽  
Canlong He ◽  
Hari N. Agrawal
Keyword(s):  
Residual Stress ◽  
Stress Measurement ◽  
Low Cycle Fatigue ◽  
High Sensitivity ◽  
Fatigue Loading ◽  
Moiré Interferometry ◽  
Spot Weld ◽  
Moire Interferometry ◽  
Spot Welds ◽  
Full Field

Residual stress distribution has been determined in spot welds, which are generally used to join mild steel sheets. Various spot weld configurations were investigated using the full-field, experimental, optical technique of high sensitivity moire´ interferometry. These stresses were found to be in the range 250–300 MPa (tensile) in the center and decreased to 40–100 MPa (tensile) at the edge of the weld nugget. Low cycle fatigue loading of the spot weld caused the residual stress to drop in the weld center by about 30 percent and increase at the edges by as much as 100 percent.

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.

scholarly journals THE INFLUENCE OF MORTAR MICROSTRUCTURE ON ITS THERMAL EXPANSION COEFFICIENT

2003 ◽  
Vol 9 (1) ◽  
pp. 45-51
Author(s):  
Darius Zabulionis ◽  
Gediminas Marčiukaitis
Keyword(s):  
Thermal Expansion ◽  
Bulk Modulus ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Composite Structure ◽  
Parametric Study ◽  
Coefficient Of Thermal Expansion ◽  
Thermal Strain ◽  
Interfacial Transition Zone ◽  
Aggregate Fractions

Thermal strain is one of the factors causing additional stresses in a composite structure. It is necessary to calculate the coefficient of thermal expansion in evaluating thermal strains. According to the research, concrete is a material consisting of three phases: aggregate, interfacial transition zone (ITZ) and cement paste. The article presents the technique which enables the estimation of the thermal expansion coefficient of the mortar consisting of various aggregate fractions and covered with ITZ layer. A parametric study of various ITZ layer characteristics influencing the coefficient of thermal expansion has been carried out in the present paper. It has been determined that dry mortar or concrete could be treated as a material consisting of two components. While evaluating moist mortar or concrete it is necessary to take into account the depth of the ITZ the bulk modulus and the coefficient of thermal expansion.

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