One of the biggest challenges for power electronic devices is to be reliable in harsh environments. The operating temperatures in typical applications can go as high as 200ºC. The die attachment material of a power electronic device is one of the weak links in the system. The eutectic Sn-Pb solder alloy, which is the most commonly used permanent interconnect in electronics packaging cannot fulfill these service requirements, hence there is a need to find suitable replacements. Durability characterization is essential in order to accurately…
Author: Gupta, Shirish Anurag
Source: University of Maryland
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Contents
Chapter 1. Introduction
1.1 Motivation
1.2 Die Attach Reliability Concerns
1.3 Literature Survey
1.4 High Temperature Pb-based Solders
1.5 Organization of Thesis
Chapter 2. Test Methodology: Direct Local Measurement Technique for Constant Strain Rate Testing
2.1 Specimen Configuration
2.2 Specimen Preparation
2.3 Test Equipment – MTS TytronTM 250 MicroForce Testing System
2.4 Direct Local Measurement using Miniature Extensometer
2.5 Subtraction of Compliance Effects of Copper
2.6 Constitutive Modeling – A Partitioned Approach
2.7 Experimental Procedure – Determination of Constants
2.7.1 Time-independent Elasticity – Modulus Test
2.7.2 Time-independent Plasticity – Constant Strain Rate Test
2.7.3 Time-dependent Creep – Constant Strain Rate Test
Chapter 3. Implementation of Direct Local Measurement Technique for Constitutive Property Measurements of 95.5Pb2Sn2.5Ag Solder Alloy
3.1 Modification of Solder Joint Geometry
3.2 Modification of Specimen Preparation Procedure for the 95.5Pb2Sn2.5Ag solder alloy
3.2.1 Preparation Procedure
3.2.2 Specimen Quality Verification
3.2.2.1 Non-destructive Testing
3.2.2.2 Destructive Testing
3.3 Experimental Set-up
3.4 Subtraction of Compliance Effects of Copper
Chapter 4. Mechanical and Constitutive Properties of 95.5Pb2Sn2.5 Solder Alloy
4.1 Introduction
4.2 Yield Stress and Ultimate Tensile Strength
4.3 Time Independent Elasticity
4.4 Time Independent Plasticity
4.5 Time Dependent Steady-State Creep
4.6 Discussion
Conclusions
Contributions
Appendix A: Testing Procedures using MTS TytronTM 250 1:19 PM 01/28/2009
References