Measurements of outgassing rates in a field of analysis

Abstract

For many years since 1990's, we have developed thermal desorption spectrometer (TDS) as ex-situ analysis tool, used in wide fields of process control and development of new materials such as semiconductor and at display devices, polymers, catalyst, metals and so on. Recently TDS is required not just for qualitative or relative comparison but for quantification of thermally-desorbed gasses. This paper describes the performance and the several key points for quantification in TDS measurements; (1) repeatability of measurements and simple calibration method using referenced materials of ion implanted Si, (2) stability of sensitivity in quadrupole mass spectrometer (QMS), and (3) mass discrimination of QMS sensitivity and its correction method. The correction method for mass discrimination of QMS is successfully demonstrated. Entire results indicate that the TDS measurement provides a good quantitative evaluation of many kinds of outgassing species not only hydrogen and water vapor.