INTEGRATED ETCHING OF THIN DIELECTRIC HARD MASKS AND OF FLUORINATED AND NON-FLUORINATED ORGANIC LOW-K MATERIALS

摘要

Plasma etching processes for opening very thin hard masks and for organic low-k materials were developed. The processes were run in production friendly fully integrated process sequences in three dedicated chambers of a multi chamber cluster tool. The results obtained for hard mask opening are described by a simple model which illustrates how critical tight control of etch rates and etch rate non-uniformities of the two dielectric etches used for hard mask opening are, as the thickness of the hard mask film decreases. The experiments show that fluorinated low-k materials can be patterned without any micromasking even in large open areas; this is attributed to a chemical reaction of fluorine with micromasking material. The results furthermore show that non-fluorinated low-k films display at least in medium density reactors a tendency for micromasking preferentially in large exposed areas.