Minimally Invasive Supervision of Plasma-assisted Dielectric Deposition Processes

Abstract

This paper introduces a minimally invasive in-situ plasma monitoring concept suited for the challenging conditions in dielectric deposition processes. Based on the so-called stacked planar multipole resonance probe (spMRP), the sensor is placed directly on the plasma-remote side of a dielectric substrate to be coated, thus minimizing its influence on the process. The sensor’s electric field penetrates both substrate and deposited dielectric layers and couples into the plasma. This enables an effective supervision of the plasma parameters required for process control at the point of highest interest. The effect of increasing coating thicknesses on the measurement performance is investigated within 3D electromagnetic field simulations. Final measurements in an argon-oxygen plasma depositing aluminium oxide confirm both the general suitability of the proposed concept as well as the insensitivity to additional dielectric coatings.