Size and constraining effects in lead-free solder joints

Joël Cugnoni 1Aissa Mellal 1Jolanta Janczak-Rusch 2John Botsis 1

1. Ecole Polytechnique Federale de Lausanne (EPFL), Ecublens, Lausanne 1015, Switzerland
2. Empa, Materials Technology and Research (Empa), Überlandstrasse 129, Dübendorf 8600, Switzerland

Abstract

Because of the tremendous developments in advanced processing technologies, the dimensions of contemporary electronic devices and interconnections have become smaller and smaller. Moreover, in recent electronic designs the solder joints may not only be electrical interconnections but may also play a significant role in the mechanical stability of the joint.

Due to the strong influence of geometrical constraints and processing parameters, the macroscopic stress-strain constitutive law of lead-free solder materials must be determined in the most geometrically and physically realistic conditions. In order to identify the elasto-visco-plastic constitutive law of Sn-Ag-Cu solders, a special optical strain measurement technique based on Digital Image Correlation has been developed to study the strain field in an idealized joint during a tensile test. Experimental results of the stress-strain relationship at room temperature of geometrically constrained Sn-Ag-Cu joints have been evaluated.

The measured strain field (Digital Image Correlation) and load data have then been used in an inverse numerical identification procedure to determine the true elasto-plastic constitutive law of the solder. The effects of geometrical constraints in a real solder joint with heterogeneous stress and strain fields are then studied by comparing the apparent (constrained) and true (non-constrained) stress-strain relationships. Experimental stress-strain relations for Sn-Ag-Cu joints of 0.25 mm , 0.5 mm and 1.0 mm thickness are presented and the constraining effects are discussed.

Related papers
  1. Experimental evaluation of melting point depression in AlSi/AlN nanomultilayer system
  2. How to join heat sensitive materials?
  3. The Wetting Behaviour and Interface Structure of Unreinforced and Particle Reinforced Lead-Free Solders
  4. Optimization of particle reinforced lead-free solders
  5. Microstructural evaluation during particles addition to lead-free solders
  6. Evaluation of fibre-cement interfacial properties by SEM-based push-out tests
  7. Fractography as a tool to optimize joint design and the brazing process
  8. Development of nanoparticle reinforced brazing filler metals and solders: the aspects of downscaling from micro to nanoscale
  9. Description of the mechanical performance of Cu-SnAgCu-Cu joints
  10. Comparison of three different active filler metals used for brazing ceramic-to-ceramic and ceramic-to-metal joints
  11. On the Relief of the Residual Stresses in Ceramic-Metal Joints by a Layered Braze Structure
  12. Model for intermetallic phase and intermetallic compound solidification during diffusion soldering
  13. Transition from solidification to the first solid/solid transformation during diffusion soldering

Presentation: oral at E-MRS Fall Meeting 2005, Symposium H, by Joël Cugnoni
See On-line Journal of E-MRS Fall Meeting 2005

Submitted: 2005-05-20 07:27
Revised:   2009-06-07 00:44
Google
 
Web science24.com
© 1998-2017 pielaszek research, all rights reserved Powered by the Conference Engine