System and process for detecting leaks in sealed articles

摘要

A system and method for leak testing a plurality of hermetic electronic devices of the type that have an internal chamber that is isolated from ambient conditions by a seal structure is advantageously designed to be able to calculate the leak rate of each individual device in a manner that is independent of structural manufacturing variances that typically exist within a sampling of such devices. The method preferably involves positioning a plurality of the hermetic electronic devices within a test area, and then stimulating the hermetic electronic devices with a modulated input of energy, such as by varying the ambient pressure about the devices. A property such as the physical position of one portion of a lid of each of the hermetic electronic devices is then sensed. The sensed property is one that is known to change as a first function of the modulated input of energy and also as a second function of pressure conditions within the hermetically sealed internal chamber. The first and second functions are linearly independent of each other. By comparing the stimulation of the devices to the sensed property and by discriminating using the two known functions a leak rate is determined for each individual device that is substantially independent of variances, such as differences in lid thickness that may exist between the different devices. Accordingly, an accurate determination of leak rate may be made with a minimum of calibration.