Spray coating of photoresist for three dimensional micromachining

Abstract

New technique using spray coating of photoresist is developed for realizing the photolithography on samples having deep three dimensional structures. This technique is compatible with the highly developed planar photolithography and therefore promising for realizing the wide variety of micro-electro mechanical systems. The photoresist is sprayed as minute particles and carried to the sample surface. The particle dries individually without suffering the problem due to the resist flow or the surface tension (e.g., disconnection of film or accumulation of resist at corners). The appropriate drying condition realizes the thin and uniform resist film. The effects of some parameters which have the significant influence to the spray coating condition are examined. The thin and uniform photoresist film is reproducibly obtained on the deep three dimensional structure. The patterning is demonstrated using the conventional exposing equipment not only at the planar area but also corners or slant surfaces.