Process for depositing and developing a plasma polymerized organosilicon photoresist film

Abstract

A process for patterning a feature on a substrate using a plasma polymerized methylsilane (PPMS) photoresist layer or similar organosilicon film. The process includes the step of depositing a PPMS film having upper and lower strata such that the upper stratum is more photosensitive to ultraviolet radiation than is the lower stratum. In one embodiment, the upper and lower strata are formed in a multistep deposition process that, preferably, takes place in a single deposition chamber. In another embodiment, the upper and lower strata are formed by a process in which deposition parameters are modified to deposit a PPMS layer having a photosensitivity gradient between the upper and lower strata. In still another embodiment, various intermediate strata are formed. Preferably, each intermediate stratum has a photosensitivity that is higher than the stratum directly beneath it. Also disclosed is a process for etching a PPMS layer that increases the etch selectivity of PPMS relative to PPMSO from an initial low etch selectivity to a higher etch selectivity at a later stage of the etching process. In one currently preferred embodiment, the etch selectivity used during a first etching step of the process is less than 4:1 and the etch selectivity used during a second etching step, subsequent to the first step, is greater than 5:1. In an even more preferred embodiment, the etch selectivity of the first step is between 2-3:1 and the etch selectivity of the second step is greater than 8:1. Optionally, a third etching step, performed between the first and second etching steps may be employed where the etch selectivity is between 3-8:1.

Dependencies are inferred from the claim text.