True Gas Sensing in Vacuum and Atmosphere, Where RGAs Fail to Go

Abstract The nature of vacuum based processing is inherently problematic as the vacuum quality can be adversely affected by a range of effects that can contaminate the environment. If the level of such contamination exceeds acceptable limits, the quality of the produced parts will fall below standard and result in lower productivity and higher costs. The larger and more complex the vacuum processing chamber, the higher the probability of contamination, and the bigger the disruption to efficient production. Prediction and measurement of contamination within a vacuum is possible by residual gas analysis (RGA). Residual gas analysis can detect the presence and quantity of the gaseous species present, and as such is the most universal tool available to combat the difficulties experienced whilst vacuum processing. Traditionally vacuum residual gas analysis is performed by quadrupole mass spectrometry. A new method of residual gas analysis based upon remote plasma optical emission spectroscopy has overcome the drawbacks of using quadrupole based RGAs on large scale industrial vacuum systems. This remote plasma type of RGA operates over a wide range of vacuum pressures and is highly robust which guarantees continuous operation and avoids maintenance. The data provided can be used for smart digital control and monitoring of most forms of vacuum processes and ultimately ensures improved productivity.