Moulding of plastics enables fluidic and optical features to be integrated into a single element. This is particularly an advantage for product designs that impose space and weight constraints. Therefore, the use of plastic for biomedical and non telecommunications orientated optical applications continues to grow as design engineers take advantage of the ease of fabrication and the material flexibility.
LIGA presents itself as a method ideally suited for the production of moulds for the manufacture of plastic microcomponents. Although LIGA is synonymous for lithography using synchrotron radiation x-rays, many other lithography and non-lithography methods for master production have been developed in the last few years, offering cost effective solutions to template production. These include UV LIGA methods, where deep resists such as SU-8 and AZ 4562, are employed for the master production. In addition, excimer laser micromachining offers a cost effective and efficient method for master fabrication, which later forms a template for electroforming. Furthermore, the use of Advanced Silicon Etching methods to prestructure silicon templates for electroforming, allows to the production of stepped mould inserts, which are particularly useful for microfluidic applications.
This paper provides an overview of the different technologies, emphasizing the strengths and application areas of the different master structuring technologies. Considerations for the electroforming of microstructured mould inserts are also presented.