A methodology for accelerated testing by mechanical actuation of MEMS devices

In order to fully understand the reliability issues around MEMS device a means of carrying out accelerated testing is required. This research investigated the use of mechanical means to actuate MEMS membranes so that lifetime estimates could be obtained. A Talysurf measurement system was adapted to allow a MEMS membrane to be cycled by moving it with a stylus. This cycling was continued until the membrane failed according to the definitions provided by the device manufacturer. This experiment was repeated with different forces and this allowed standard life testing techniques to be used to produce a prediction of lifetime under normal use conditions. The lifetime predicted was of the order of 30 million cycles and was in keeping with the expectations of the device manufacturer for this geometry and materials. This demonstrated that the acceleration technique is a valid way to accelerate the device type and so can provide a method for predicting lifetimes for other devices. Such a prediction will be useful in Understanding the reliability of MEMS devices in actual usage.

► We develop a method of mechanical actuation of MEMS membranes.
► Mechanical actuation is carried out using a modified Talysurf machine.
► Membranes are cycled to failure under elevated stress levels.
► Accelerated life analysis is used to produce a lifetime for the devices.
► Predicted life is found to be within the expectations of the device manufacturer.