Integrated piezoelectric microelectromechanical ultrasound transducer (PMUT) on integrated circuit (IC) for fingerprint sensing
Granted: March 1, 2022
Patent Number:
11263424
Microelectromechanical (MEMS) devices and associated methods are disclosed. Piezoelectric MEMS transducers (PMUTs) suitable for integration with complementary metal oxide semiconductor (CMOS) integrated circuit (IC), as well as PMUT arrays having high fill factor for fingerprint sensing, are described.
Measuring a noise level of an accelerometer
Granted: February 22, 2022
Patent Number:
11255876
A method of measuring noise of an accelerometer can comprise exposing the accelerometer comprising a micro-electro-mechanical system (MEMS) component coupled to an application specific integrated circuit component (ASIC), to an external environmental input, with the MEMS component being configured to provide a first output to the ASIC based on the external environmental input. The method can further comprise estimating a first noise generated by operation of the MEMS component, and…
Operating a fingerprint sensor comprised of ultrasonic transducers and a presence sensor
Granted: February 8, 2022
Patent Number:
11243300
In a method for operating a fingerprint sensor including a plurality of ultrasonic transducers and a presence sensor, the presence sensor proximate the fingerprint sensor is activated, where the presence sensor is for detecting interaction between an object and the fingerprint sensor. Subsequent to detecting interaction between an object and the fingerprint sensor at the presence sensor, a subset of ultrasonic transducers of the fingerprint sensor is activated, the subset of ultrasonic…
Stress reduced diaphragm for a micro-electro-mechanical system sensor
Granted: February 1, 2022
Patent Number:
11237043
A micro-electro-mechanical system (MEMS) sensor can comprise a substantially rigid layer having a center. The MEMS sensor can further comprise a movable membrane that can be separated by a gap from, and be disposed substantially parallel to, the substantially rigid layer. The MEMS sensor can further include a plurality of pedestals extending into the gap, where a first pedestal of the plurality of pedestals can be of a first size, and be disposed a first distance from the center, and a…
Adapting a quality threshold for a fingerprint image
Granted: January 25, 2022
Patent Number:
11232549
In a method for adapting a quality threshold for a fingerprint image, a fingerprint image is received. An image quality of the fingerprint image is determined. Provided the image quality of the fingerprint image does not satisfy a quality threshold, the quality threshold is decreased. Provided the image quality of the fingerprint image does satisfy a decreased quality threshold, the fingerprint image is forwarded to a matcher for fingerprint authentication.
MEMS structure for offset minimization of out-of-plane sensing accelerometers
Granted: January 25, 2022
Patent Number:
11231441
Exemplary embodiment of a tilting z-axis, out-of-plane sensing MEMS accelerometers and associated structures and configurations are described. Disclosed embodiments facilitate improved offset stabilization. Non-limiting embodiments provide exemplary MEMS structures and apparatuses characterized by one or more of having a sensing MEMS structure that is symmetric about the axis orthogonal to the springs or flexible coupling axis, a spring or flexible coupling axis that is aligned to one of…
Semiconductor device with patterned contact area
Granted: January 25, 2022
Patent Number:
11230470
The present invention relates to semiconductor devices, such as microelectromechanical (MEMS) devices, with improved resilience during manufacturing. In one embodiment, a MEMS device includes a MEMS structure; a substrate situated parallel to the MEMS structure and positioned a first distance from the MEMS structure; and a bump stop structure formed on the substrate between the substrate and the MEMS structure, wherein the bump stop structure substantially traces a perimeter of the…
Sensor with integrated heater
Granted: January 18, 2022
Patent Number:
11225409
A device includes a microelectromechanical system (MEMS) sensor die comprising a deformable membrane, a MEMS heating element, and a substrate. The MEMS heating element is integrated within a same layer and a same plane as the deformable membrane. The MEMS heating element surrounds the deformable membrane and is separated from the deformable membrane through a trench. The MEMS heating element is configured to generate heat to heat up the deformable membrane. The substrate is coupled to…
Reduced MEMS cavity gap
Granted: January 11, 2022
Patent Number:
11220423
Provided herein is a method including forming a MEMS cap. A cavity is formed in the MEMS cap wafer, and a bond material is deposited on the MEMS cap wafer, wherein the bond material lines the cavity after the depositing. The MEMS cap wafer is bonded to a MEMS device wafer, wherein the bond material forms a bond between the MEMS cap wafer and the MEMS device wafer. A MEMS device is formed in the MEMS device wafer. The bond material is removed from the cavity.
Fake finger detection based on transient features
Granted: January 4, 2022
Patent Number:
11216681
In a method for determining whether a finger is a real finger at an ultrasonic fingerprint sensor, a sequence of images of a fingerprint of a finger are captured at an ultrasonic fingerprint sensor, wherein the sequence of images includes images captured during a change in contact state between the finger and the ultrasonic fingerprint sensor. A plurality of transient features of the finger is extracted from the sequence of images. A classifier is applied to the plurality of transient…
Latent fingerprint detection
Granted: January 4, 2022
Patent Number:
11216641
In a method for operating a fingerprint sensor, a fingerprint capture operation is performed on a fingerprint of a finger contacting the fingerprint sensor. A finger lift action is detected. It is determined whether a latent fingerprint remains on a contact surface of the fingerprint sensor subsequent the finger lift action. If it is determined that a latent fingerprint remains on the contact surface of the fingerprint sensor subsequent the finger lift action, instruction on addressing…
Ultrasonic fingerprint sensor with a contact layer of non-uniform thickness
Granted: January 4, 2022
Patent Number:
11216632
An ultrasonic sensor includes a two-dimensional array of ultrasonic transducers, wherein the two-dimensional array of ultrasonic transducers is substantially flat, a contact layer having a non-uniform thickness overlying the two-dimensional array of ultrasonic transducers, and an array controller configured to control activation of ultrasonic transducers during an imaging operation for imaging a plurality of pixels at a plurality of positions within the two-dimensional array of…
Method of addressing dissimilar etch rates
Granted: December 28, 2021
Patent Number:
11211258
A method for DRIE matched release and/or the mitigation of photo resist pooling, comprising: depositing a first mask layer over a first surface of a silicon substrate; exposing a first portion and second portion of the first mask layer to a first etch process, wherein the exposing forms a first exposed layer; depositing a second mask layer over the first mask layer; exposing a third portion of the second mask layer to a second etch process, wherein the exposing forms a second exposed…
Fake finger detection using ridge features
Granted: November 30, 2021
Patent Number:
11188735
In a method for determining whether a finger is a real finger at an ultrasonic fingerprint sensor, a first image of a fingerprint pattern is captured at an ultrasonic fingerprint sensor, wherein the first image is based on ultrasonic signals corresponding to a first time of flight range. A second image of the fingerprint pattern is captured at the ultrasonic fingerprint sensor, wherein the second image is based on ultrasonic signals corresponding to a second time of flight range, the…
Systems and methods for operating a MEMS device based on sensed temperature gradients
Granted: November 30, 2021
Patent Number:
11186479
An exemplary microelectromechanical device includes a MEMS layer, portions of which respond to an external force in order to measure the external force. A substrate layer is located below the MEMS layer and an anchor couples the substrate layer and MEMS layer to each other. A plurality of temperature sensors are located within the substrate layer to identify a temperature gradient being experienced by the MEMS device. Compensation is performed or operations of the MEMS device are…
Analog-to-digital converter with split-gate laddered-inverter quantizer
Granted: November 23, 2021
Patent Number:
11184019
An analog-to-digital converter (ADC) with split-gate laddered-inverter quantizer is presented herein. The ADC converts, via the split-gate laddered-inverter quantizer, an analog input voltage into a digital output value. The split-gate laddered-inverter quantizer separately couples, during respective phases of a clock signal via respective capacitances, a reference voltage and an input voltage corresponding to the analog input voltage to P-type metal-oxide-semiconductor (PMOS) gates of a…
Ultrasonic fingerprint sensor with a contact layer of non-uniform thickness
Granted: November 16, 2021
Patent Number:
11176345
An ultrasonic sensor includes a two-dimensional array of ultrasonic transducers, wherein the two-dimensional array of ultrasonic transducers is substantially flat, a contact layer having a non-uniform thickness overlying the two-dimensional array of ultrasonic transducers, and an array controller configured to control activation of ultrasonic transducers during an imaging operation. During the imaging operation, the array controller is configured to control a transmission frequency of…
Package level thermal gradient sensing
Granted: November 16, 2021
Patent Number:
11174153
A microelectromechanical (MEMS) device may be coupled to a dielectric material at an upper planar surface or lower planar surface of the MEMS device. One or more temperature sensors may be attached to the dielectric material layer. Signals from the one or more temperature sensors may be used to determine a thermal gradient along on axis that is normal to the upper planar surface and the lower planar surface. The thermal gradient may be used to compensate for values measured by the MEMS…
Integrated MEMS cavity seal
Granted: November 16, 2021
Patent Number:
11174151
A microelectromechanical (MEMS) system may comprise multiple sensors within cavities of the MEMS system. The operation of different sensors requires different pressures within the respective cavities. A first cavity may be sealed at a first pressure. A through-hole may be etched into a cap layer of the MEMS system to introduce gas into a second cavity such that the cavity has a desired pressure. The cavity may then be sealed by a MEMS valve to maintain the desired pressure in the second…
Humidity correction method in thermistor based gas sensing platform
Granted: November 2, 2021
Patent Number:
11162928
A gas sensor may include a plurality of elements that are responsive to particular gases based at least in part on the temperature of the temperature sensitive element. A first of the elements may be a gas detection element heated to a temperature at which it is responsive to a gas of interest. A plurality of additional elements may be configured in a reference element network and heated to a temperature at which they are not responsive to the gas of interest but are instead responsive…
