Post Exposure Silyation of a Positive Photoresist

A silylation process employing hexamethyldisilazane (HMDS\u3e as a silylating agent was examined as a ethod of combining the high resolution capabilities of a multilevel resist and the process simplicity of a single layer resist scheme. Atmospheric pressure vapor phase silylation and liquid phase silylation were performed on Kodak 809 Micropositive resist. The vapor phase silylation did not result in significant alteration of the etch characteristics. The liquid phase silylation was performed for several HMDS concentrations in Freon. Liquid phase silylation was shown to provide significant etch selectivity upon exposure to an oxygen plasma