Abstract: A surface microstructure is superimposed on the surface of a replication mould such as an injection moulding tool insert by laser interference exposure of a mask pattern and etching or electroplating the additional microstructure. The technique enables the post-processing of planar and non-planar replication moulds with additional microstructure to improve the functionality and value of the moulded components. A major area of application is an anti-reflection surface for injection moulded polymer optical components, achieved by the superposition of submicrometer anti-reflection grating structure onto injection moulding tool inserts.