Abstract: Low-cost, robust, and high performance microelectromechanical systems (MEMS) acoustic sensors are described. Described MEMS acoustic sensors can comprise a set of etch release structures in the acoustic sensor membrane that facilitates rapid and/or uniform etch release of the acoustic sensor membrane. In addition, MEMS acoustic sensors can comprise a set of membrane position control structures of the acoustic sensor membrane that can reduce the bending stress of the acoustic sensor membrane. MEMS acoustic sensors can further comprise a three layer acoustic sensor membrane that provides increased robustness. Further design flexibility and improvements are described that provide increased robustness and/or cost savings, and a low cost fabrication process for MEMS acoustic sensors is provided.

Abstract: In an embodiment, a method for fabricating a Microelectromechanical System (MEMS) microphone includes depositing, on a frontside of a wafer, a first oxide layer over a silicon nitride thin film and over and adjacent the wafer, wherein the silicon nitride thin film is disposed over the wafer, depositing a membrane protection layer over the first oxide layer between a first side of a first cavity formed in the wafer and a second side of a second cavity formed in the wafer, depositing a second oxide layer over and adjacent the membrane protection layer, depositing a first membrane nitride layer over the second oxide layer, depositing a membrane polysilicon layer over the first membrane nitride layer, depositing a second membrane nitride layer over the membrane polysilicon layer, depositing a third oxide layer over the second membrane nitride layer and depositing a fourth oxide layer over the third oxide layer.

Abstract: A pressure sensor includes a first electrode, a plurality of cavities, and a second electrode. The second electrode is disposed opposite the first electrode through the plurality of cavities. The second electrode includes a flat structure spanning two adjacent cavities of the plurality of cavities.

Abstract: A microelectromechanical (MEMS) microphone with membrane trench reinforcements and method of fabrication is provided. The MEMS microphone includes a flexible plate and a rigid plate mechanically coupled to the flexible plate. The MEMS microphone includes a stoppage member affixed to the rigid plate and extending perpendicular relative to a surface of the rigid plate opposite the surface of the flexible plate. The stoppage member limits motion of the flexible plate. The rigid plate includes a reverse bending edge that include a first lateral etch stop that includes a first corner radius and a second lateral etch stop that includes a second corner radius. The first corner radius is more than 100 nanometers and the second corner radius is more than 25 nanometers. Further, a lateral step width between the first corner radius and the second corner radius is less than around 4 micrometers.

Abstract: A microelectromechanical (MEMS) microphone with membrane trench reinforcements and method of fabrication is provided. The MEMS microphone includes a flexible plate and a rigid plate mechanically coupled to the flexible plate. The MEMS microphone includes a stoppage member affixed to the rigid plate and extending perpendicular relative to a surface of the rigid plate opposite the surface of the flexible plate. The stoppage member limits motion of the flexible plate. The rigid plate includes a reverse bending edge that includes a first lateral etch stop that includes a first corner radius and a second corner radius. The first corner radius is more than 100 nanometers and the second corner radius is more than 25 nanometers. Further, a lateral step width between the first corner radius and the second corner radius is less than around 4 micrometers.

Abstract: A microelectromechanical (MEMS) microphone with membrane trench reinforcements and method of fabrication is provided. The MEMS microphone includes a flexible plate and a rigid plate mechanically coupled to the flexible plate. The MEMS microphone includes a stoppage member affixed to the rigid plate and extending perpendicular relative to a surface of the rigid plate opposite the surface of the flexible plate. The stoppage member limits motion of the flexible plate. The rigid plate includes a reverse bending edge that include a first lateral etch stop that includes a first corner radius and a second lateral etch stop that includes a second corner radius. The first corner radius is more than 100 nanometers and the second corner radius is more than 25 nanometers. Further, a lateral step width between the first corner radius and the second corner radius is less than around 4 micrometers.

Abstract: A MEMS switch includes a first signal line provided in a first beam, a first GND adjacent to the first signal line, a second signal line provided in a second beam, and a second GND adjacent to the second signal line. A contact terminal is fixed to any one of the first signal line and the second signal line and performs connection between the first signal line and the second signal line according to deformation of the first beam.

Abstract: A MEMS switch includes a first signal line provided in a first beam, a first GND adjacent to the first signal line, a second signal line provided in a second beam, and a second GND adjacent to the second signal line. A contact terminal is fixed to any one of the first signal line and the second signal line and performs connection between the first signal line and the second signal line according to deformation of the first beam.

Abstract: Methods to form a three-dimensionally curved pad in a substrate and integrated circuits incorporating such a substrate are disclosed. An example method to form a three-dimensionally curved pad comprises isotropically etching a portion of a surface of a substrate to form a recess having a radial shape, forming a conductive layer in the recess to form the bonding pad, and placing a conductive element in the pad.