Abstract
A compact apparatus for ion-attachment mass spectrometry (IAMS) has been developed, which is used for in-situ analyses of exhaust gases including perfluoro compounds (PFCs) from a dry-etching machine generating cyclo-C4F 8/O 2/ Ar plasma. The soft attachment of Li+ to target molecules plays an important role in the ionization technique in LAMS; fragment-free molecular ions are observed even for reactive or unstable molecules such as PFCs in the exhaust gases. IAMS is, therefore, capable of accurate and in-situ analysis of multi-component gases including unknown species. In the present measurements, a lot of new species which are not considered even in the current protocol for the measurement of PFCs were observed in the exhaust gases. IAMS is found to be useful for accurate analyses of the exhaust gases from plasmas as well as diagnoses of plasmas themselves.
