As semiconductor devices have become increasingly miniaturized, the ability to control very small Critical Dimensions (CDs) during the etching process has become crucial through controlled plasma processes. Hence, diagnosing plasma and reflecting this in the process to enhance yield is of paramount importance. Typically, a Single Langmuir Probe (SLP) is utilized for plasma diagnostics.
Recent semiconductor devices have embraced structural modifications, including vertical stacking, to overcome the limitations of miniaturization. Particularly, memory devices have seen improvements through the transition to 3D stack structures. To address the challenges of etching high aspect ratio contact holes, the Bosch process, which alternates between deposition of a passivation layer on the pattern wall to prevent sidewall etching and etching steps, has been utilized.