UV and electron-assisted oxidation of Al and Ru

UV and electron-assisted oxidation of Al and Ru

Ernst, M.A.

Thijsse, B.J. (promotor)
Sloof, W.G. (promotor)

Mechanical, Maritime and Materials Engineering

Materials Science & Engineering

2009-09-09

To ensure a continuing miniaturization in the semiconductor industry, new technologies need to be developed to define ever smaller patterns on the silicon substrates. One of these emerging technologies is extreme ultraviolet (EUV) lithography. Unfortunately, EUV light causes oxidation of the optical components inside the lithography machine that are needed to focus the light beam. The effect of oxidation can be mitigated by providing the optics with a protective coating. The transition metal ruthenium was chosen as candidate material for such a coating for its optical properties in the EUV domain. As metallic ruthenium is not widely used, knowledge about the oxidation of ruthenium is fragmented. In this dissertation, the oxidation behaviour of ruthenium and the influence of EUV light on the oxidation are studied. To this end, single crystals of ruthenium were exposed to oxygen at various temperatures and oxygen partial pressures in a vacuum environment and analysed with a variety of surface analytical techniques. To gain insight in the processes occurring inside the oxide layer, a kinetic simulation model needed to be developed based on the hopping transport of particles through an oxide layer on a metal surface. This simulation model was verified with experimental results obtained from aluminium, since the oxidation of aluminium is well-understood, and then applied to the oxidation of ruthenium. The combined results of experimental and simulation analysis lead to an understanding of the oxidation behaviour of ruthenium and the role of EUV light on oxidation behaviour.

oxidation
aluminium
ruthenium
EUV lithography

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9789085704072

Institutional Repository

doctoral thesis

(c) 2009 Ernst, M.A.