RF plasma cleaning of optical surfaces: A study of cleaning rates on different carbon allotropes as a function of RF powers and distances

TL;DR

This study investigates the effectiveness of RF plasma cleaning for removing carbon contaminants from optical surfaces, analyzing how cleaning rates vary with RF power, distance, and carbon types.

Contribution

It provides a detailed analysis of cleaning efficiency for different carbon allotropes using RF plasma, considering various operational parameters and physical phenomena.

Findings

Cleaning rates depend on RF power and distance.

Different carbon allotropes show varying cleaning efficiencies.

Physical mechanisms underlying the process are discussed.

Abstract

An extended study on an advanced method for the cleaning of carbon contaminations on large optical surfaces using a remote inductively coupled low pressure RF plasma source (GV10x downstream asher) is reported in this work. Technical as well as scientific features of this scaled up cleaning process are analyzed, such as the cleaning efficiency for different carbon allotropes (amorphous and diamond-like carbon) as a function of feedstock gas composition, RF power (ranging from 30 to 300W), and source-object distances (415 to 840 mm). The underlying physical phenomena for these functional dependences are discussed.