general information - 1. overview
of composition, mode of action and specific properties
of e-beam resists
E-beam resists (electron beam resists) are in particular designed for electron beam, ion beam and deep UV applications for the manufacture of highly integrated structures. They are used for mask production and for maskless lithographic procedures to structure layers or wafers in prototype or small batch production.
E-beam resists are utilised in direct writing procedures or in mask-based technologies (e.g. stencil mask) and can also be used for multi-layer processes (e.g. the fabrication of T-gates). In thin layers (< 100 nm), e-beam resists are perfectly suited for nanometer lithography. In optimised processing regimes it is possible to realise structures of <10 nm at a film thickness of 50 nm.
E-beam resists are applied by spin coating and are characterised by a very good adhesion to silicon, glass and
most metals. For thin resists, the optimum rotational speed ranges from 2000 to 3000 rpm, for thick resists between 500 and 2000 rpm. For novolac-based resists, spin speeds of up to 9000 rpm may be used. If the high molecular PMMA resists (600K, 950K) are processed, spin speeds above of 6000 rpm should however be avoided since these resists tend to show the so-called “cotton candy” effect. Depending on the type of resist, e-beam resist films of 10 nm to 4 μm can be realised.