Pilot Electrodeposition of Aluminium for Microelectronics, Aerospace and Automotive Applications

Wednesday, 4 October 2017: 11:00
Chesapeake G (Gaylord National Resort and Convention Center)
F. M. Stiemke, B. Iliev (IOLITEC Ionic Liquids Technologies GmbH), P. von Czarnecki (IOLITEC Ionic Liquids Technologies INC.), and T. J. S. Schubert (IOLITEC Ionic Liquids Technologies GmbH)
Ionic liquids are salts which have per definition a melting point below 100 ° C. They are non-flammable and have a high thermal stability as well as a very low vapor pressure. Many ionic liquids are characterized by a wide electrochemical window of up to seven volts, which in principle also allows the deposition of metals with high reduction potentials. Since most ionic liquids are aprotic solvents, this results in another important advantage over aqueous electroplating systems: the lack of hydrogen evolution and the corresponding hydrogen embrittlement of the deposited metal layer.

Due to its high reduction potential, aluminum cannot be deposited from aqueous solutions in pure state. However, there are very interesting applications for aluminum coatings in the area of corrosion protection or in the design sector. For example, in the (automotive) design area, chromium coatings can be replaced by shiny aluminum layers. Even in the electronics industry, homogeneous aluminum coatings on different substrates open up new possibilities for increased efficiency, e.g. copper printed circuit board tracks are replaced by corresponding aluminum ones with similar conductivity. This saves, among other things, costs for raw materials and reduces the weight of the component, which can be a significant advantage in this industry. A galvanic coating with aluminum from non-flammable ionic liquids is therefore promising from the technical point of view.

In a European joint project, the automated aluminum deposition from ionic liquids on plastic and metal substrates for the automotive industry and turbine construction could now be successfully demonstrated in a pilot plant.

The talk presents our current research results on the development and the scaling up of aluminum deposition from ionic liquids for applications in automotive engineering as well as in the field of microelectronics on circuit boards and Si wafers. We will report on the high requirements that the electrolytes place on plant design and components, the influence of additives or impurities such as water on the quality of the aluminum deposition. In addition, the influence of the post-treatment of the so produced aluminum layers will be presented. A life-cycle analysis of the electrolyte is presented for the economic and ecological consideration of this aluminum deposition process.