Diagnostics for plasma processing-an overview

Abstract

Summary form only given, as follows. The use of plasmas in the production of integrated circuits has lead to the development of a variety of diagnostic tools. The goal of plasma diagnostics in this application is twofold. The diagnostic tools are used to aid in the understanding of plasma physics and chemistry, so that processes and hardware may be optimized. For this goal the diagnostic tools are used in an R&D setting. Plasma diagnostic methods are also sought after to serve as sensors for process control. For this application the diagnostic techniques must be low cost, non-invasive, robust, and repeatable. Much understanding has been obtained by applying the classic plasma diagnostic techniques, such as Langmuir probes, optical spectroscopy, and microwave interferometry, to processing plasmas. More detailed information has come from advanced diagnostics such as energy analysis of charged particles, laser induced fluorescence, and mass spectrometry. The demands of process control have been met by non-invasive techniques that require minimal access to the plasma, such as optical emission spectroscopy, RF measurements outside the plasma source, and to some extent by residual gas analysis. An overview of these diagnostics are given, along with their contribution to the understanding of plasma physics and plasma chemistry.