Noise reduction in the recording of holographic masks in photoresist

ABSTRACT The lithography of gratings or structures using photoresist holographic masks is very critical, in particular when high selectivity etching processes were employed. In this paper we study the effect of the mask profile and of the phase perturbations during the holographic exposure in the noise of the photoresist masks. It is shown that the use of appropriateconditions of development and exposure may reduce significantly this noise allowing the recording of high aspect ratiostructures and the use of selective deposition techniques.Keywords: holographic optical components, photoresist, gratings 1. INTRODUCTION Holographic recording in photoresist films is used to perform matrices for holograms and diffractive optics replication. Thestructure recorded in photoresist can be used also as a mask to transfer the pattern to the substrate by chemical or reactive ionetching. Using this technique new types of diffractive optical components and deep high spatial frequency structures may be