Current status of atomic layer etching and its adoption to low-k fine patterning: An industrial perspective

Atomic layer etching (ALE) has attracted considerable attention as an alternative to conventional reactive ion etching due to its potential for reduced ion-induced damage under controlled conditions, improved selectivity, and minimized pattern loading effects. However, the industrial adoption of ALE has been slow. In this work, we analyze the key barriers limiting widespread implementation from an industrial perspective, including low etch throughput, imperfect self-limiting behavior, particle generation, and process complexity. Despite these challenges, we demonstrate that ALE enables vertical profile formation in low-k dielectric etching under reduced ion energy, increasing Cu volume by up to ∼67%. Because conventional O2-based activation induces chemical damage, mitigating capacitance degradation requires optimized material conditions and underscores the need for O2-free chemistries. Finally, we propose transitioning from conventional multistep ALE cycles to simplified “one ALE cycle per one plasma pulse” schemes to simultaneously address throughput, particle, and stability issues, which are critical to the industry perspective.