The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.
Aalto

Time-Dependent Microstructural and Compositional Changes at the Interfaces between Materials in Electronics

Kari Rönkä

Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Department of Electrical and Communications Engineering, Helsinki University of Technology for public examination and debate in Auditorium S4 at Helsinki University of Technology (Espoo, Finland) on the 16th of March, 2001, at 12 noon.

Overview in PDF format (ISBN 951-22-5383-6)   [624 KB]
Errata (in PDF)
Dissertation is also available in print (ISBN 951-22-5373-9)

Abstract

Combined thermodynamic and kinetic models and concepts were presented for the better understanding, prediction and control of the time-dependent microstructural and compositional changes caused by diffusion, dissolution and chemical reaction processes at the interfaces between different materials. The chemical compatibility of the multitude of materials used in high-density electronics interconnections is increasingly important with decreasing solder volumes and thinner metallization layers, but needs also to be considered in the kinetically constrained local edge regions of the joints in conventional surface mount assemblies. The thermodynamic assessment of the joining or bonding system combined with the introduced qualitative kinetic understanding and models can indeed be used to improve the design and production of electronics devices. However, the presence of liquid phase, irregularities such as grain boundaries as well as the lack of kinetic and thermodynamic data and realistic kinetic software cause practical limitations to the extensive modelling concept.

This thesis consists of an overview and of the following 4 publications:

  1. K.J. Rönkä, A.A. Kodentsov, P.J.J. van Loon, J.K. Kivilahti, and F.J.J. van Loo, Thermodynamic and Kinetic Study of Diffusion Paths in the System Cu-Fe-Ni, Metallurgical and Materials Transactions A. 27A (1996) pp. 2229-38.
  2. K.J. Rönkä, F.J.J. van Loo, and J.K. Kivilahti, Thermodynamic and Kinetic Study of Diffusion Paths in the System Cu-Ag-Zn, Zeitschrift für Metallkunde, 88(1) (1997) pp. 9-13.
  3. K.J. Rönkä, F.J.J. van Loo, and J.K. Kivilahti, The Local Nominal Composition - Useful Concept for Microjoining and Interconnection Applications, Scripta Materialia, 37(10) (1997) pp. 1575-81.
  4. K. J. Rönkä, F. J. J. van Loo, and J. K. Kivilahti, A Diffusion-Kinetic Model for Predicting Solder/Conductor Interactions in High Density Interconnections, Metallurgical and Materials Transactions A, 29A (1998) pp. 2951-56.

Keywords: materials in electronics, joint interfaces, diffusion kinetics, microstructural and compositional changes, thermodynamics, soldering

This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.

© 2001 Helsinki University of Technology


Last update 2011-05-26