US Patent 7210337 - MEMS leak detector

http://www.freepatentsonline.com/7210337.html

One of the largest markets for MEMS is motion sensors which utilize the resonant response of a proof mass to detect movement. However, the pressure of the environment in which the MEMS device is encapsulated can alter the resonant response. This patent from Honeywell seeks to detect leaks in a MEMS package to detect pressure changes having unwanted effects on the sensors operation.

1. A method for detecting a leak in a MEMS sensor package, wherein the MEMS sensor package includes a sensor cavity that encloses a MEMS sensor, wherein the MEMS sensor includes a mechanical oscillating element with a Quality (Q) value, the method comprising: measuring a first Q value of the MEMS sensor at a first time; applying a pressure differential between the sensor cavity and the exterior of the MEMS sensor package; and measuring a second Q value of the MEMS sensor at a second time, wherein the second time is later than the first time.