On the Multiscale Finite Element Analysis for Interfacial Fracture in Cu/Low-K Interconnects

2007 ◽  
Author(s):  
Tz-Cheng Chiu ◽  
Huang-Chun Lin
Keyword(s):  
Thin Film ◽  
Fracture Mechanics ◽  
Interface Crack ◽  
Integrated Circuit ◽  
Flip Chip ◽  
Thermal Loading ◽  
Global Analysis ◽  
Crack Problem ◽  
Element Analysis ◽  
Low K

The interface crack problem in integrated circuit devices was considered by using global and local modeling approach. In the global analysis the thin film interconnect was modeled by a homogenized layer with material constants obtained from representative volume element (RVE) analysis. Local analyses were then considered to determine fracture mechanics parameters. It was shown that the multiscale model with RVE approach gives accurate fracture mechanics parameters for an interface crack under either thermal or mechanical loads; while significant error was observed when the thin film layers are ignored in the global analysis. The problem of an interface crack between low-k dielectric and etch-stop thin film in a flip-chip package under thermal loading was also investigated as an application example of the multiscale modeling.

An Interfacial Delamination Analysis for Multichip Module Thin Film Interconnects

1996 ◽  
Vol 118 (4) ◽  
pp. 206-213 ◽  
Author(s):  
K. X. Hu ◽  
C. P. Yeh ◽  
X. S. Wu ◽  
K. Wyatt
Keyword(s):  
Thin Film ◽  
Phase Angle ◽  
Structural Reliability ◽  
Thermal Loading ◽  
Multichip Module ◽  
Crack Model ◽  
Element Analysis ◽  
Delamination Growth ◽  
Interfacial Delamination ◽  
Functional Behavior

Analysis of interfacial delamination for multichip module thin-film interconnects (MCM/TFI) is the primary objective of this paper. An interface crack model is integrated with finite-element analysis to allow for accurate numerical evaluation of the magnitude and phase angle of the complex stress intensity factor. Under the assumption of quasi-static delamination growth, the fate of an interfacial delamination after inception of propagation is determined. It is established that whether an interfacial delamination will continue to grow or become arrested depends on the functional behavior of the energy release rate and loading phase angle over the history of delamination growth. This functional behavior is numerically obtained for a typical MCM/TFI structure with delamination along die and via base, subjected to thermal loading condition. The effect of delamination interactions on the structural reliability is also investigated. It is observed that the delamination along via wall and polymer thin film can provide a benevolent mechanism to relieve thermal constraints, leading to via stress relaxation.

Experiment and Numerical Analysis of the Residual Stresses in Underfill Resins for Flip Chip Package Applications

2005 ◽  
Vol 127 (1) ◽  
pp. 47-51 ◽  
Author(s):  
Man-Lung Sham ◽  
Jang-Kyo Kim
Keyword(s):  
Numerical Analysis ◽  
Residual Stresses ◽  
Integrated Circuit ◽  
Flip Chip ◽  
Coefficient Of Thermal Expansion ◽  
Flexural Modulus ◽  
Curing Temperature ◽  
Electronic Packages ◽  
Element Analysis ◽  
Plastic Package

Polymeric encapsulant is widely used to protect the integrated circuit chips and thus to enhance the reliability of electronic packages. Residual stresses are introduced in the plastic package when the polymer is cooled from the curing temperature to ambient, from which many reliability issues arise, including warpage of the package, premature interfacial failure, and degraded interconnections. Bimaterial strip bending experiment has been employed successfully to monitor the evolution of the residual stresses in underfrill resins for flip chip applications. A numerical analysis is developed to predict the residual stresses, which agree well with the experimental measurements. The changes of material properties, such as flexural modulus and coefficient of thermal expansion, of the resins with temperature are taken into account in the finite element analysis.

In‐Situ Mapping and Modeling Verification of Thermomechanical Deformation in Underfilled Flip‐Chip Packaging Using Moiré Interferometry

1996 ◽  
Vol 445 ◽  
Author(s):  
Xiang Dai ◽  
Connie Kim ◽  
Ralf Willecke ◽  
Paul S. Ho
Keyword(s):  
Flip Chip ◽  
Thermal Loading ◽  
Deformation Monitoring ◽  
Moiré Interferometry ◽  
Moire Interferometry ◽  
Fringe Analysis ◽  
Element Analysis ◽  
Solder Bumps ◽  
Thermomechanical Deformation

AbstractAn experimental technique of environmental moiré interferometry has been developed for in‐situ monitoring and analysis of thermomechanical deformation of microelectronics packages subjected to thermal loading under a controlled atmosphere. Coupled with fractional fringe analysis and digital image processing, the environmental moiré interferometry technique achieves accurate and realistic deformation monitoring with high sensitivity and excellent spatial resolution. It has been applied to investigate the thermomechanical deformations induced by thermal loading in an underfilled flip‐chip‐on‐board packaging. The effects of temperature change in the range of 102 °C to 22 °C are analyzed for underfill and solder bumps. In addition, shear deformation and shear strains across the solder bumps are determined as a function of temperature. The experimental results are compared with the results of a finite element analysis for modeling verification. Good agreement between the modeling results and experimental measurements has been found in the overall displacement fields. Through this study, the role of underfill in the thermomechanical deformation of the underfilled flip‐chip package is determined.

Interconnect Design and Thermal Stress/Strain Analysis of Flip Chip Packaging

2006 ◽  
Vol 326-328 ◽  
pp. 521-524
Author(s):  
Chang Ming Liu ◽  
Chang Chun Lee ◽  
Hsiao Tung Ku ◽  
Chien Chia Chiu ◽  
Kuo Ning Chiang
Keyword(s):  
Solder Joint ◽  
Electronic Packaging ◽  
Flip Chip ◽  
Thermal Loading ◽  
Equivalent Plastic Strain ◽  
Engineering Application ◽  
Stress Strain ◽  
Element Analysis ◽  
Design Guideline ◽  
Solder Balls

As the interconnection density of electronic packaging continues to increase, the fatigueinduced solder joint failure of surface mounted electronic devices become one of the most critical reliability issues in electronic packaging industry. Especially, prediction of the shape of solder joint is a major event in the development of electronic packaging for its practical engineering application. In conventional electronic packages, the geometrical dimensions of solder balls and solder pads of the package are the same. In this research, a hybrid method combined with analytical and energybased methods is utilized to predict force-balanced heights and geometry profiles of solder balls under various solder volume and pad dimensions as well as their relative location during the reflow process. Next, a non-linear finite element analysis is adopted to investigate the stress/strain behavior of solder balls in flip chip package. The results reveal that as the flip chip package contains larger solder balls located at the corner area underneath the chip, the maximum equivalent plastic strain/stress is evidently reduced and the reliability cycles under thermal loading are enhanced. Furthermore, the results presented in this research can be used as a design guideline for area array interconnections.

Investigation of a new fracture mechanics specimen for thin film adhesion measurement

1997 ◽  
Vol 12 (10) ◽  
pp. 2673-2685 ◽  
Author(s):  
Maarten P. de Boer ◽  
Michael Kriese ◽  
William W. Gerberich
Keyword(s):  
Thin Film ◽  
Fracture Mechanics ◽  
Integrated Circuit ◽  
Carbon Layer ◽  
Tangential Load ◽  
Film Adhesion ◽  
Adhesion Measurement ◽  
Thin Carbon ◽  
Thin Film Adhesion ◽  
Processing Techniques

We have investigated mechanical probing of a precracked fine line structure as a new type of thin film fracture mechanics specimen. An idealized mechanics analysis is first presented. Experimentally, two types of precracks are formed. A thin carbon layer to which other layers weakly adhere creates a “processed precrack” by integrated circuit processing techniques. An “indented processed precrack” is formed by precision alignment of a sharp microwedge. The processed precrack is found to reduce the critical tangential load by 50% from a non-precracked line, while the indented processed precrack lowers the load by 200%. From this, a reasonable value of adhesion may be directly calculated. Crack path behavior is observed to depend on strength of the interface. In the case of a weak interface, the crack remains in the interface as it extends. For a strong interface, it kinks into the substrate if the crack is initially short, but remains in the interface if it is initially long. Given the experimental evidence, the mechanics are slightly modified to quantitatively model the experimental data.

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