Infrared Diode Laser Spectrometric Analysis of Moisture in Hermetic Packages: Performance of a Routine Analytical System

The development of a technique for moisture analysis in hermetic packages, based on tunable diode laser infrared spectrometry, has been pursued at AT&T Bell Labs and reported on at past moisture analysis conferences. This analytical technique has matured to the point where an analytical system is now commercially available. The design, sensitivity for moisture, calibration, operation, throughput, and performance of such a system at the AT&T manufacturing facility in Allentown will be discussed. A comparison of this technique to the mass spectrometric technique in use at AT&T ALlentown will also be made. This will include both burst mode simulation and package analysis results. The effect of the following parameters on the results obtained by both techniques will be discussed: package volume, fill gas composition, speed of gas release from the package puncture, and bakeout time. Recommendations for the use of both types of instruments in a device manufacturing environment will be suggested.