Minimally Invasive Supervision of Plasma-assisted Dielectric Deposition Processes

The Planar Multipole Resonance Probe: A Minimally Invasive Monitoring Concept for Plasma-Assisted Dielectric Deposition Processes

“…Thus, a perturbation-free monitoring of important process-relevant plasma parameters, such as electron density and collision frequency, via resonance frequency and width is enabled. Compared to our previous work in [27], an expanded and more detailed description of the monitoring concept as well as an extensively enlarged simulative investigation in CST Microwave Studio considering a broad range of coating materials and thicknesses as well as an additional evaluation of the resonance width have been presented. Considering coating thicknesses up to 100 µm and relative permittivities higher than 2, a worst case deviation of the resonance frequency below 2.5% and of the width below 8% with respect to the coating-free case could be observed in the simulations.…”

“…In this article, a prototype with a DuPont951PT ceramic layer having a fired thickness of around 100 µm is used. Since this is 2.5 times thicker than the glass top layer of the prototype used in [27], an increased insensitivity is expected in comparison. In contrast to the ideal model, the insulation distance between reactor wall and electrodes is not infinitely small.…”

“…Afterward, the normalized real part of Y can be used to determine the resonance parameters f res = ω res /(2π) and f = ω/(2π), which already can be used for monitoring general fluctuations. Apart from this simple monitoring option, Simulation model in CST Microwave Studio (cutting plane): spMRP inserted through the substrate holder/grounded reactor electrode on the substrate's plasma-remote side together with an enlarged view of the material stack [27].…”

“…In light of the previous studies, further scientific research concerning the applicability of the pMRP for long-term monitoring within the challenging environment of deposition processes is of particular interest for thin-film processing. In [27], we already presented first results with the pMRP, which were obtained during measurements within a dielectric sputter deposition process. Instead of mounting the sensor within the reactor wall, the concept of placing it directly on the plasma-remote side of a dielectric substrate to be coated was first introduced.…”

“…Fig. 3.Simulation model in CST Microwave Studio (cutting plane): spMRP inserted through the substrate holder/grounded reactor electrode on the substrate's plasma-remote side together with an enlarged view of the material stack[27].…”