Abstract: Processes and fixtures for producing electromechanical devices, and particularly three-dimensional electromechanical devices such as inertial measurement units (IMUs), through the use of a fabrication process and a three-dimensional assembly process that entail joining single-axis device-IC chips while positioned within a mounting fixture that maintains the orientations and relative positions of the chips during the joining operation.

Abstract: A sensing module and method for monitoring various physical parameters, and particularly environmental parameters to which a living body may be subjected, for example, impacts and shock wave pulses. The module at least one energy storage device and at least one set of electromechanical sensing elements contained in a housing. The sensing elements are responsive to an external environmental input, and each sensing element defines an open electrical path when not subjected to the input, is operable to define a closed electrical path that produces an output in response to the input if the input exceeds a threshold of the sensing element. The module generates data corresponding to the outputs of the sensing elements and records the data.

Abstract: Implantable sensing modules and methods for monitoring various physical parameters, including physical parameters of a living body and environmental parameters to which the living body may be subjected, for example, impacts. A method for monitoring impacts to which a living body is subjected entails the use of an implantable sensing module that has a rigid housing containing at least one energy storage device and at least one electromechanical sensing element that is responsive to impacts. The module generates data corresponding to impacts to which the electromechanical sensing element is subjected, and records the data in memory. The module is preferably implanted in a living body so that the module is connected to a rigid portion of the living body, in particular, a bone or tooth.

Abstract: A wafer bonding process that compensates for curvatures in wafer surfaces, and a wafer stack produced by the bonding process. The process entails forming a groove in a surface of a first wafer, depositing a bonding stack on a surface of a second wafer, aligning and mating the first and second wafers so that the bonding stack on the second wafer contacts a bonding site on the first wafer, and then heating the first and second wafers to reflow the bonding stack. The groove either surrounds the bonding site or lies entirely within the bonding site, and the heating step forms a molten bonding material, causes at least a portion of the molten bonding material to flow into the groove, and forms a bonding structure that bonds the second wafer to the first wafer. Bonding stacks having different lateral surface areas can be deposited to form bonding structures of different heights to compensate for variations in the wafer gap.

Abstract: A sensing system, sensing method, and method of producing a sensing system capable of providing a cumulative measurement capability, such as in the form of a RFID tag capable of measuring cumulative heat and humidity for continuous monitoring of storage and shipping conditions of various goods. The system includes integrated circuitry and a plurality of sensing elements, preferably having cantilevered bimorph beams. Each sensing element is responsive to an environmental condition so as to deflect toward and away from open contacts in response to changes in the environmental condition. Each sensing element produces a digital output when it contacts and closes its open contacts. The integrated circuitry interfaces with the sensing elements so that the digital outputs of the sensing elements are processed to generate a system output of the sensing system.

Abstract: A sensor and sensing method capable of full-differential symmetry to minimize bias drift and improve stability of the sensor output. The sensor includes a sensing element, sense electrodes capacitively coupled to the sensing element to generate capacitive outputs that vary in response to the motion of the sensing element, and a differential readout device. The sense electrodes are electrically separable into at least two pairs of differential sense electrodes. The readout device performs a sampling sequence of at least two sampling cycles during which the readout device samples the capacitive outputs of the sense electrodes and produces at least two differential outputs based on the difference between the capacitive outputs within each pair of differential sense electrodes. The readout device then calculates an average of the differential outputs of the sampling sequence to produce an output of the differential readout device, and thereafter repeats the sampling sequence and calculation.

Abstract: A bimorphic structure responsive to changes in an environmental condition, sensor structures incorporating one or more of such bimorphic structures, and a method of forming such bimorphic structures. The sensor structure has an electrically-conductive first contact on a substrate, and a bimorph beam anchored to the substrate so that a portion thereof is suspended above the first contact. The bimorph beam has a multilayer structure that includes first and second layers, with the second layer between the first layer and the substrate. A portion of the first layer projects through an opening in the second layer toward the first contact so as to define an electrically-conductive second contact located on the beam so as to be spaced apart and aligned with the first contact for contact with the first contact when the beam sufficiently deflects toward the substrate.

Abstract: A micromachined sensor and a process for fabrication and vertical integration of a sensor and circuitry at wafer-level. The process entails processing a first wafer to incompletely define a sensing structure in a first surface thereof, processing a second wafer to define circuitry on a surface thereof, bonding the first and second wafers together, and then etching the first wafer to complete the sensing structure, including the release of a member relative to the second wafer. The first wafer is preferably a silicon-on-insulator (SOI) wafer, and the sensing structure preferably includes a member containing conductive and insulator layers of the SOI wafer. Sets of capacitively coupled elements are preferably formed from a first of the conductive layers to define a symmetric capacitive full-bridge structure.

Abstract: A bimorphic structure responsive to changes in an environmental condition, sensor structures incorporating one or more of such bimorphic structures, and a method of forming such bimorphic structures. The sensor structure has an electrically-conductive first contact on a substrate, and a bimorph beam anchored to the substrate so that a portion thereof is suspended above the first contact. The bimorph beam has a multilayer structure that includes first and second layers, with the second layer between the first layer and the substrate. A portion of the first layer projects through an opening in the second layer toward the first contact so as to define an electrically-conductive second contact located on the beam so as to be spaced apart and aligned with the first contact for contact with the first contact when the beam sufficiently deflects toward the substrate.

Abstract: A capacitive pressure sensor and method for its fabrication. The sensor is fabricated from first and second wafers to have a mechanical capacitor comprising a fixed electrode and a moving electrode defined by a conductive plate. The sensor further has a diaphragm on a surface of the first wafer that is mechanically coupled but electrically insulated from the conductive plate. A conductive layer on the surface of the first wafer is spaced apart from the conductive plate to define the fixed electrode. The second wafer is bonded to the first wafer and carries interface circuitry for the sensor, including the conductive plate and the fixed electrode which are between the first and second wafers and electrically connected to the interface circuitry. At least an opening is present in the first wafer and its first conductive layer by which the diaphragm is released and exposed to an environment surrounding the sensor.

Abstract: A three-axis inertial sensor and a process for its fabrication using an silicon-on-oxide (SOI) wafer as a starting material. The SOI wafer has a first conductive layer separated from a second conductive layer by an insulative buried oxide (BOX) layer. The SOI wafer is fabricated to partially define in its first conductive layer at least portions of proof masses for z, x, and y-axis sensing devices of the sensor. After a conductive deposited layer is deposited and patterned to form a suspension spring for the proof mass of the z-axis sensing device, the SOI wafer is bonded to a substrate that preferably carries interface circuitry for the z, x, and y-axis devices, with the SOI wafer being oriented so that its first conductive layer faces the substrate. Portions of the BOX layer are then etched to fully release the proof masses.

Abstract: A MEMS module that contains at least one integrated energy storage device whose discharge is minimized and controlled, so that power is available for system operation over longer periods of time. The MEMS module includes a device electrically coupled to the energy storage device for controlling charge transfers from the energy storage device while preventing charge leakage from the energy storage device. The controlling device includes a plurality of integrated MEMS switches that define open electrical paths that prevent charge leakage from the energy storage device through the MEMS switches, and are then operable to define closed electrical paths to allow charge transfers from the energy storage device, and preferably also allow charge transfers to the energy storage device, through the MEMS switches. The charge transfer can be utilized to power electronic circuits or store data in non-volatile digital memory.

Abstract: A micromachined sensor and a process for fabrication and vertical integration of a sensor and circuitry at wafer-level. The process entails processing a first wafer to incompletely define a sensing structure in a first surface thereof, processing a second wafer to define circuitry on a surface thereof, bonding the first and second wafers together, and then etching the first wafer to complete the sensing structure, including the release of a member relative to the second wafer. The first wafer is preferably a silicon-on-insulator (SOI) wafer, and the sensing structure preferably includes a member containing conductive and insulator layers of the SOI wafer. Sets of capacitively coupled elements are preferably formed from a first of the conductive layers to define a symmetric capacitive full-bridge structure.