Stiction Suppression in High Volume MEMS Products

Analog Devices has shipped over 120 million MEMS inertial sensors (accelerometers and gyros). Most are used in automotive air bag systems so high reliability is absolutely critical. the DMD die used in the Texas Instruments’ DLP image projection systems have up to 1.3 million micromirrors on each die that are designed to touch and release. the DLP product line also has a well-established record of high reliability. Clearly, both Companies have solved the problem of MEMS stiction to the extent that it no longer impacts field reliability. However, stiction remains a primary cause of failure in other micromachined products that are produced on less mature processes than those employed by high volume manufacturers like ADI and TI. This paper discusses the fundamental causes of stiction and the techniques that commercial MEMS suppliers use to suppress it.