Challenges in Plasma Surface Interactions Control for Microelectronics Nanofabrication

Plasma-based etching methods have been essential for the progress of nanofabrication approaches required to build current semiconductor devices. This has been possible because of a continuous growth in our ability to control plasma-based etching approaches, and success in meeting the advanced technological challenges. In this presentation we will discuss several key examples of the recent evolution of challenges on plasma surface interaction control. This includes plasma etching of high aspect ratio (HAR) features necessary for 3D fabrication and the general issue of how surface processes may be controlled in the fabrication of such features. Directional etching of HAR features can be combined with isotropic etching of lateral features with high materials etching selectivity, e.g. Si₃N₄ relative to SiO₂. Another topic that has seen a great deal of recent development is atomic scale processing, including area selective deposition and etching. The constraints on plasma etching approaches are also made more severe by environmental concerns. An example is the American Innovation and Manufacturing (AIM) Act of 2020 which directs a phase down of the production and use of hydrofluorocarbons which have been very important precursor gases for plasma etching of dielectric materials.