Lotus Archives: Myth Busting - Conformal films via Plasma ALD!

There is a common (and persistent) misconception that plasma-enabled ALD processing is unable to grow conformal films on high aspect ratio (AR) features. LotusAT debunked this myth at the 2018 SVC Tech Con when Eric Dickey presented, "Conformality of Coatings Produced using High Speed Spatial PEALD." In it, LotusAT demonstrates uniform conformality (~100 %) for SiO2, Nb2O5 films in trenches up to 60:1 AR at processing speed of 1 ALD cycle per second! Experimental results suggest that several, precursor-dependent operating parameters may play important roles in achieving conformal coatings at high speed, such as: substrate temperature, precursor concentration, and plasma current.

Speaking of precursor dependency, ALD Al2O3 conformality on high AR surfaces has been relatively difficult to achieve compared to other materials (SiO2, TiO2). In 2019, Arts et al. suggest that there is a material dependency for this radical recombination probability tendency. By contrast, LotusAT has recently been working with a particular Al precursor chemistry that appears to enable highly efficient ALD Al2O3 conformality. More on that to come, stay tuned!

Click here to review Eric's 2018 SVC Tech Con presentation, "Conformality of Coatings Produced using High-Speed Spatial PEALD."