Developing New Lead-free Solder Materials: COST 531, a Concerted European Action
University of Vienna, Department of Inorganic Chemistry - Materials Chemistry, Waehringerstr. 42, Wien A-1090, Austria
A European Action on lead-free soldering has been initiated in 2002 under the COST Program of the EU. Its goal is the establishment of a database containing the relevant knowledge on possible lead-free solder materials and to provide the expertise for selecting particular materials for specific soldering purposes. By May 2005, 22 European countries have signed the corresponding Memorandum of Understanding, in addition, three non-European research organizations have been accepted as partners, with one application (Ukraine) pending.
The Action is structured into four Working Groups: WG 1 is responsible for experimental data on phase equilibria and thermochemical properties, WG 2 carries out the theoretical modeling of the corresponding phase diagrams, WG 3/4 investigates physical and chemical properties, and WG 5/6 is mainly responsible for reliability issues. Currently scientists from about 45 European research institutions are involved. WG 1 and 2 (together with SGTE) have identified nine quaternary systems as the immediate goal for a thermodynamic database; they comprise five possible ternary solder alloys together with relevant substrate materials. WG 3/4 and WG 5/6 cooperate in setting up a database on physical and mechanical properties of possible lead-free solders.
In our laboratory in Vienna we are currently working on a number of ternary systems to understand the interaction of Sn-Ag-Cu and Sn-Ag-In solders with Ni or Pd substrates. This research comprises experimental phase diagram investigations, thermodynamic measurements, and CALPHAD type optimizations. In addition, we are investigating various physical and mechanical properties of solder joints formed between Sn-Ag and Sn-Ag-In alloys and Cu contacts, in particular the so-called size effect, i.e. the influence of the size of the joint on the mechanical properties.
Research in Austria is supported by the Austrian Science Foundation under Projects No. P15620, P16495, and P17346.
Presentation: oral at E-MRS Fall Meeting 2005, Symposium H, by Herbert Ipser
See On-line Journal of E-MRS Fall Meeting 2005
Submitted: 2005-04-25 09:45 Revised: 2009-06-07 00:44