Challenges in Plasma Etching for Microelectronics Nanofabrication

Plasma-based etching methods along with photolithographic methods and thin film deposition have enabled the exponential progress in semiconductor technology referred to as Moore’s Law. This has been possible because of a continuous evolution of plasma-based etching approaches that could meet the growing requirements of advanced microelectronics manufacturing. A review of the current challenges of plasma etching has recently been published,¹ and in this presentation we will focus on a subset of the topics reviewed there. We will discuss several examples of the recent evolution of challenges on plasma surface interaction control, including plasma etching of high aspect ratio (HAR) features required for 3D fabrication, and advances in cryogenic etching that has led to significant advances in this area. Atomic scale processing and ultra-high materials selectivity, including area selective deposition and etching, is another area that has seen significant development and will be discussed. One area that will play an increasing role in plasma etching development is the introduction of more sustainable practices enforced by legislative environmental regulations, e.g. 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.

¹ See J. Vac. Sci. Technol. B 42, 041501 (2024); https://doi.org/10.1116/6.0003579