Parts-per-million water vapor generating system used to simulate moisture in small integrated circuit packages

A simple, portable system has been developed and tested for generating a known water-vapor content is selected permanent gases or gas mixtures. Parts-per-million values ranging from 250 to 20 000 are generated in a continuous flowing stream at flowrates ranging from 50 to 200 cm(3)/min. A known volume of the flowing gas can be selected to simulate the internal free volume and internal pressure of hermetically sealed packages as small as 0.04 cm(3). By using a variety of available connectors, the selected volume of gas may be transferred into the inlet system of a mass spectrometer for water-vapor calibration. Generator stabilizing time and upper flowrate limits are given along with test results when compared to a Transfer Humidity Standard.