IN-LINE CRITICAL LEAK RATE TESTING OF VACUUM-SEALED AND BACKFILLED RESONATING MEMS DEVICES

摘要

Vacuum wafer bonding technology provides a number of very effective techniques to produce low-cost, hermetic sealed packages for micromachined sensors and actuators. Beside the protection of the device from outside environmental stresses, the package must also provide an interior environment compatible with the device performance and reliability. The paper reviews the shortcomings of existing fine leak tests to assess the stability of the cavity atmosphere over long time. A new ultra-fine leak test is proposed that has the potential to be used for in-line critical leak rate testing on wafer level before wafer dicing. It is shown how the test can be made sensitive enough to predict the cavity pressure for a demanded device lifetime of 15 years.