A laboratory study was made of the performance of a miniature-size, thin-film aluminum oxide humidily sensor over a range of ambient temperatures from 0°C to 40°C and encompassing humidities from 40 to 78,000 parts per million by volume (ppm-v). Hysteresis and temperature effects of the sensors were obtained from tests performed at ambient temperatures 40°C, 25°C and 0°C and encompassing relative humidities from 19 to 98 percent. Information on short-term repeatability, sensitivity and storage effects was obtained from tests performed at an ambient temperature of 23°C and encompassing humidities from 40 to 6,000 ppm-v.
There have bee numerous investigations '** substantiating the deleterious effects of internal moisture on semiconductor devices. In view of the increasing number of incidents of integrated-circuit failures due to high internal water vapour content, rejection criteria are being implemented in MIL.STD.883 as Method 1018 on 'Internal Water Vapour Content'. Method 1018 specifies the use of a small humidity sensor within the package or the measurement of the humidity of the emitted gas on puncturing the package, with the latter measurement done primarily by mass spectrometry.
Although present efforts within the industry are leading to increased intralaboratory precision and interlaboralory correlation, there is still a great need for the development of test packages with known humidity which would be suitable for use as a transfer device for interlaboratory measurements. The development of a suitable transfer standard requires the use of a well-characterized humidity sensor, mass spectrometer and test package. This paper describes the study of a commercially available humidity sensor for possible use in the study of the behavior of water vapour inside experimental test packages.
Performance characteristics of a Thin-film aluminum oxide humidity sensor - Case Study