A two-axis Lloyd's mirror interferometer for fabrication of two-dimensional diffraction gratings

摘要

A new two-axis Lloyd's mirror interferometer based on multi-beam interference is proposed. A square grating substrate with normal in the Z-axis is placed edge to edge with two rectangular mirrors with normals parallel to the XZ-plane (X-mirror) and the YZ-plane (Y-mirror), respectively. The angle between the substrate and each mirror is set to be larger than 908, so that the beams reflected by the mirrors can be superimposed with the direct beam at the substrate to produce two-dimensional (2D) diffraction grating structures in a single exposure. Sub-micron pitched 2D hole grating structures were fabricated and evaluated.