MEMS device and process

摘要

A MEMS capacitive transducer with increased robustness and resilience to acoustic shock. The transducer structure includes a flexible membrane supported between a first volume and a second volume, and at least one variable vent structure in communication with at least one of the first and second volumes. The variable vent structure includes at least one moveable portion which is moveable in response to a pressure differential across the moveable portion so as to vary the size of a flow path through the vent structure. The variable vent may be formed through the membrane and the moveable portion may be a part of the membrane, defined by one or more channels, that is deflectable away from the surface of the membrane. The variable vent is preferably closed in the normal range of pressure differentials but opens at high pressure differentials to provide more rapid equalization of the air volumes above and below the membrane.

主权项

1. A MEMS transducer comprising:
a flexible membrane the flexible membrane being moveable from an equilibrium position in response to a pressure differential across the membrane, wherein the flexible membrane has a first vent hole through the membrane; and a plug which is supported so as to lie within the first vent hole at said equilibrium position; wherein the flexible membrane is moveable with respect to the plug such that for at least one possible position of the flexible membrane, the plug does not lie within the first vent hole.