The challenges of Mechanistic Stochastic Patterning and the promise of Atomic Layer Processing
Mircea Dusa,
IMEC vzw, Kapeldreef 75, B-3001, Leuven, Belgium
At the sub-7 nm technology node, atomic-scale processing is required because pattern size is equivalent to tenths of atomic layers, and acceptable variability is less than a few atoms. The patterning process for atomic-scale features imposes the use of EUV lithography combined with atomic layer etch (ALE) and its counterpart, atomic layer deposition (ALD). Stochastic shot noise is the main challenge in EUV lithography, especially in printing atomic-scale features because it induces edge roughness (LER) and local dimensional uniformity (LCDU) that considerably limit process capability. The ALE and ALD combination help to circumvent EUV lithography limitations as a consequence of superior control of uniformity, selectivity and edge smoothing.