Texas Instruments Corporation

National Semiconductor Corporation

Ira Oaktree Wygant

Peter B Johnson

Steven J Adler

Mohammad Hadi Motieian Najar

David Brian Barkin

Joshua Posamentier

An example pressure sensor calibration apparatus includes a pressure chamber in which a first pressure sensor is to be disposed; one or more first sensors to determine a capacitance value from the first pressure sensor from a physical test performed on the first pressure sensor; the one or more first sensors to determine a first pull-in voltage value from a first electrical test performed on the first pressure sensor; a correlator to determine correlation coefficient values based on the capacitance value determined during the physical test on the first pressure sensor and the first pull-in voltage value determined during a first electrical test on the first pressure sensor; and a calibrator to determine calibration coefficient values to calibrate a second pressure sensor based on the correlation coefficient values and a second electrical test on the second pressure sensor.

Methods and apparatus to calibrate micro-electromechanical systems

Methods and apparatus to calibrate micro-electromechanical systems are disclosed. An pressure sensor calibration apparatus includes a pressure chamber in which a first pressure sensor is to be disposed; one or more first sensors to measure a first capacitance value from the first pressure sensor from a physical test performed; the one or more first sensors to measure a second capacitance value from a first electrical test performed on the first pressure sensor; and a correlator to determine correlation coefficient values based on the first capacitance value determined during the physical test on the first pressure sensor and the second capacitance value determined during the first electrical test on the first pressure sensor; and a calibrator to determine calibration coefficient values to calibrate a second pressure sensor based on the correlation coefficient values and a third capacitance value determined during a second electrical test on the second pressure sensor.

Methods and apparatus to calibrate micro-electromechanical systems are disclosed. An example pressure sensor calibration apparatus includes a mechanical lift to move a pressure sensor between a first height, a second height, and a third height; one or more sensors to measure first pressure and capacitance values at the first height, second pressure and capacitance values at the second height, and third pressure and capacitance values obtained at the third height; and a calibrator to determine calibration coefficient values to calibrate the pressure sensor based on the first pressure and capacitance values obtained at the first height, the second pressure and capacitance values at the second height, and the third pressure and capacitance values obtained at the third height.

A Capacitive Micromachined Ultrasonic Transducer (CMUT) device includes at least one CMUT cell including a first substrate having a top side including a patterned dielectric layer thereon including a thick and a thin dielectric region. A membrane layer is bonded on the thick dielectric region and over the thin dielectric region to provide a movable membrane over a micro-electro-mechanical system (MEMS) cavity. A through-substrate via (TSV) includes a dielectric liner which extends from a bottom side of the first substrate to a top surface of the membrane layer. A top side metal layer includes a first portion over the TSV, over the movable membrane, and coupling the TSV to the movable membrane. A patterned metal layer is on the bottom side surface of the first substrate including a first patterned layer portion contacting the bottom side of the first substrate lateral to the TSV.

Ultrasonic transducer device with through-substrate via

Methods and apparatus to calibrate micro-electromechanical systems are disclosed. An example pressure sensor calibration apparatus includes a pressure chamber in which a first pressure sensor is to be disposed; one or more first sensors to determine a capacitance value from the first pressure sensor from a physical test performed on the first pressure sensor; the one or more first sensors to determine a first pull-in voltage value from a first electrical test performed on the first pressure sensor; a correlator to determine correlation coefficient values based on the capacitance value determined during the physical test on the first pressure sensor and the first pull-in voltage value determined during a first electrical test on the first pressure sensor; and a calibrator to determine calibration coefficient values to calibrate a second pressure sensor based on the correlation coefficient values and a second electrical test on the second pressure sensor.

A method of forming a capacitive micro-electro-mechanical system (MEMS) sensor device includes at least one capacitive MEMS sensor element with at least one capacitive MEMS sensor cell. A patterned dielectric layer including a thick dielectric region and a thin dielectric region is formed on a top side of a first substrate. A second substrate is bonded to the thick dielectric region to provide at least one sealed micro-electro-mechanical system (MEMS) cavity. The second substrate is thinned to reduce a thickness of said second substrate to provide a membrane layer. Vias are etched through the membrane layer and said thick dielectric region extending into the first substrate to form embedded vias. A dielectric liner which lines the embedded vias is formed within the first substrate. The embedded vias are filed with electrically conductive TSV filler material to form a plurality of through-substrate vias (TSVs), said plurality of TSVs extending to at least a top of said membrane layer. A patterned metal cap layer including metal caps is formed on top of said plurality of TSVs. Trenches are etched through regions of the membrane layer for releasing a first portion of the membrane layer over said MEMS cavity to provide a MEMS electrode and to define a fixed electrode. A third substrate including an inner cavity and outer protruding portions framing said inner cavity is bonded to the thick dielectric. The protruding portions are bonded to the thick dielectric region and, together with said first substrate vacuum, seals said MEMS electrode. The plurality of TSVs on a bottom side of said first substrate are exposed.

Method of forming capacitive MEMS sensor devices

A flow meter system includes a first ultrasonic transducer array to be flush-mounted to a pipe. The system also includes a second ultrasonic transducer array to be flush-mounted to the pipe. The system further includes a controller coupled to the first and second ultrasonic transducer arrays and configured to cause bidirectional beam steering between the first and second ultrasonic transducer arrays.

Flush mounted ultrasonic transducer arrays for flow measurement

A Capacitive Micromachined Ultrasonic Transducer (CMUT) device including at least one CMUT element with at least one CMUT cell is formed. A patterned dielectric layer thereon including a thick and a thin dielectric region is formed on a top side of a single crystal material substrate. A second substrate is bonded to the thick dielectric region to provide at least one sealed micro-electro-mechanical system (MEMS) cavity. The second substrate is thinned to reduce a thickness of said second substrate to provide a membrane layer. The membrane layer is etched to form a movable membrane over said MEMS cavity and to remove said membrane layer over said top side substrate contact area. The thin dielectric region is removed from over said top side substrate contact area. A top side metal layer is formed including a trace portion coupling said top side substrate contact area to said movable membrane. From a bottom side surface of said first substrate, etching is performed to open an isolation trench around said single crystal material to form a through-substrate via (TSV) plug of said single crystal material at least under said top side substrate contact area which is electrically isolated from surrounding regions of said single crystal material.

Capacitive micromachined ultrasonic transducer (CMUT) forming

Capacitive micromachined ultrasonic transducer (CMUT) device with through-substrate via (TSV)

A packaged capacitive MEMS sensor device includes at least one capacitive MEMS sensor element with at least one capacitive MEMS sensor cell including a first substrate having a thick and a thin dielectric region. A second substrate with a membrane layer is bonded to the thick dielectric region and over the thin dielectric region to provide a MEMS cavity. The membrane layer provides a fixed electrode and a released MEMS electrode over the MEMS cavity. A first through-substrate via (TSV) extends through a top side of the MEMS electrode and a second TSV through a top side of the fixed electrode. A metal cap is on top of the first TSV and second TSV. A third substrate including an inner cavity and outer protruding portions framing the inner cavity is bonded to the thick dielectric regions. The third substrate together with the first substrate seals the MEMS electrode.

Capacitive MEMS sensor devices

A Capacitive Micromachined Ultrasonic Transducer (CMUT) device includes at least one CMUT cell including a first substrate of a single crystal material having a top side including a patterned dielectric layer thereon including a thick and a thin dielectric region, and a through-substrate via (TSV) extending a full thickness of the first substrate. The TSV is formed of the single crystal material, is electrically isolated by isolation regions in the single crystal material, and is positioned under a top side contact area of the first substrate. A membrane layer is bonded to the thick dielectric region and over the thin dielectric region to provide a movable membrane over a micro-electro-mechanical system (MEMS) cavity. A metal layer is over the top side substrate contact area and over the movable membrane including coupling of the top side substrate contact area to the movable membrane.

Capacitive micromachined ultrasonic transducer (CMUT) with through-substrate via (TSV) substrate plug

A micromachined ultrasonic transducer (MUT) circuit, which has a MUT with a MUT membrane that can vibrate back and forth to transmit an ultrasonic wave, electrically controls the movement of the MUT membrane by controllably transferring energy to the MUT membrane, thereby allowing the MUT membrane to transmit substantially any desired ultrasonic wave.

MUT circuit with an electrically controllable membrane

A capacitive micromachined ultrasonic transducer (CMUT), which has a conductive structure that can vibrate over a cavity, has a number of vent holes that are formed in the bottom surface of the cavity. The vent holes eliminate the deflection of the CMUT membrane due to atmospheric pressure which, in turn, allows the CMUT to receive and transmit low frequency ultrasonic waves.

Low frequency CMUT with vent holes

A high-frequency capacitive micromachined ultrasonic transducer (CMUT) has a silicon membrane and an overlying metal silicide layer that together form a conductive structure which can vibrate over a cavity. The CMUT also has a metal structure that touches a group of conductive structures. The metal structure has an opening that extends completely through the metal structure to expose the conductive structure.

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Palo Alto, CA, United States of America

Ira Oaktree Wygant