FORMATION OF THREE-DIMENSIONAL STRUCTURES USING GREY-SCALE PHOTOLITHOGRAPHY

摘要

Forming a three-dimensional structure includes applying photoresist on a layer and using a photolithography system to expose the photoresist. The photolithography system includes a photomask having a pattern thereon, where the pattern provides varying pattern density across a surface of the photomask and has a pitch that is less than a resolution of the photolithography system. The method includes subsequently developing the photoresist such that photoresist remaining on the layer has a three-dimensional profile defined by the photomask. An isotropic etchant is used to etch the layer such that the three-dimensional profile of the photoresist is transferred to the layer.