Failure and Reliability Analysis Influenced by Various Factors Using Accelerated Disturbed State Concept

Author(s):  
Russell D. Whitenack ◽  
Chandra S. Desai

The disturbed state concept (DSC) presented herein represents a unified and powerful approach for constitutive modeling of materials and interfaces in electronic packaging. Together with the computer finite element procedure it provides an analysis tool for calculation of stresses, strains, disturbance and cycles to failure. The accelerated procedure allows economical approximation of cycles to failure and distribution of disturbance at different cycles for design and reliability.

1997 ◽  
Vol 119 (4) ◽  
pp. 294-300 ◽  
Author(s):  
C. S. Desai ◽  
J. Chia ◽  
T. Kundu ◽  
J. L. Prince

The disturbed state concept (DSC) presented here provides a unified and versatile methodology for constitutive modeling of thermomechanical response of materials and interfaces/joints in electronic chip-substrate systems. It allows for inclusion of such important features as elastic, plastic and creep strains, microcracking and degradation, strengthening, and fatigue failure. It provides the flexibility to adopt different hierarchical versions in the range of simple (e.g., elastic) to sophisticated (thermoviscoplastic with microcracking and damage), depending on the user’s specific need. This paper presents the basic theory and procedures for finding parameters in the model based on laboratory test data and their values for typical solder materials. Validation of the models with respect to laboratory test behavior and different criteria for the identification of cyclic fatigue and failure, including a new criterion based on the DSC and design applications, are presented in the compendium paper (Part II, Desai et al., 1997). Based on these results, the DSC shows excellent potential for unified characterization of the stress-strain-strength and failure behavior of engineering materials in electronic packaging problems.


1998 ◽  
Vol 120 (1) ◽  
pp. 24-34 ◽  
Author(s):  
C. Fu ◽  
D. L. McDowell ◽  
I. C. Ume

A finite element procedure using a semi-implicit time-integration scheme has been developed for a cyclic thermoviscoplastic constitutive model for Pb-Sn solder and OFHC copper, two common metallic constituents in electronic packaging applications. The scheme has been implemented in the commercial finite element (FE) code ABAQUS (1995) via the user-defined material subroutine, UMAT. Several single-element simulations are conducted to compare with previous test results, which include monotonic tensile tests, creep tests, and a two-step ratchetting test for 62Sn36Pb2Ag solder; a nonproportional axial-torsional test and a thermomechanical fatigue (TMF) test for OFHC copper. At the constitutive level, we also provide an adaptive time stepping algorithm, which can be used to improve the overall computation efficiency and accuracy especially in large-scale FE analyses. We also compare the computational efforts of fully backward Euler and the proposed methods. The implementation of the FE procedure provides a guideline to apply user-defined material constitutive relations in FE analyses and to perform more sophisticated thermomechanical simulations. Such work can facilitate enhanced understanding thermomechanical reliability issue of solder and copper interconnects in electronic packaging applications.


Author(s):  
Mark D. Nickerson ◽  
Chandrakant S. Desai

Thermomechanical, power temperature cycling (PTC) and vibration analyses were performed on a 313 staggered pin PBGA package using plastic and viscoplastic disturbed-state damage models. An accelerated finite element failure analysis was performed using a newly developed procedure. Validations were performed using published PBGA test data. The disturbed state concept was used to model the disturbance (damage) accumulated in PBGA solder joints subjected to thermal cycling (PTC and TCT), vibration, and vibration coupled with three distinct temperatures. 2D FEA plastic and viscoplastic models were created based on a diagonal “slice” of the PBGA. This allowed the most critical solder balls (under the die and furthest DNP) to be analyzed in the same model. The thermal cycling results indicate that the solder balls under the die are the most likely to fail. The vibration results indicate the solder balls furthest from the package center are most likely to fail. The vibration results, coupled with distinct isothermal temperatures, indicate that as temperature increases, the cycles to failure decreases.


1998 ◽  
Vol 120 (1) ◽  
pp. 48-53 ◽  
Author(s):  
C. Basaran ◽  
C. S. Desai ◽  
T. Kundu

The finite element procedure with the unified disturbed state modeling concept presented in Part I, Basaran et al. (1998), is verified here with respect to laboratory test results for Pb40/Sn60 eutectic solder alloy. This solder alloy is a commonly used interconnection material for surface mount technology packages. It is demonstrated that the proposed procedure provides highly satisfactory correlation with the observed laboratory behavior of materials and with test results for a chip-substrate system simulated in the laboratory.


1998 ◽  
Vol 120 (1) ◽  
pp. 41-47 ◽  
Author(s):  
C. Basaran ◽  
C. S. Desai ◽  
T. Kundu

Accurate prediction of the thermomechanical cyclic behavior of joints and interfaces in semiconductor devices is essential for their reliable design. In order to understand and predict the behavior of such interfaces there is a need for improved and unified constitutive models that can include elastic, inelastic, viscous, and temperature dependent microstructural behavior. Furthermore, such unified material models should be implemented in finite element procedures so as to yield accurate and reliable predictions of stresses, strains, deformations, microcracking, damage, and number of cycles to failure due to thermomechanical loading. The main objective of this paper is to present implementation of such an unified constitutive model in a finite element procedure and its application to typical problems in electronic packaging; details of the constitutive model are given by Desai et al. (1995). Details of the theoretical formulation is presented in this Part 1, while its applications and validations are presented in Part 2, Basaran et al. (1998).


2000 ◽  
Vol 123 (1) ◽  
pp. 19-33 ◽  
Author(s):  
Chandra S. Desai ◽  
Russell Whitenack

A number of models for thermomechanical stress analysis and fatigue failure of materials are reviewed and their capabilities and limitations are identified. The unified disturbed state concept (DSC) for constitutive modeling of materials and interfaces is presented and compared with other approaches. An approximate procedure based on the DSC is proposed for accelerated design-analysis and cyclic fatigue failure. Solutions of example problems using the DSC and associated computer (FE) procedures are included to illustrate its integrated and improved capabilities for analysis of stresses, strains, microcracking, fracture and fatigue failure, and reliability.


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