# US 2023/0273084 A1 · Packaged pressure sensor device and corresponding method for detecting the presence of foreign material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0273084 A1 - Document ID: US20230273084A1 - Status: Published application - Kind: A1 - Application number: 18/171,163 - Filed: 2023-02-17 - Published: 2023-08-31 - Earliest claimed: 2022-02-28 - Assignees: STMicroelectronics S.r.l. - Applicants: STMICROELECTRONICS S.r.l. - Inventors: Domenico GIUSTI; Enri DUQI - Web page: https://patentgrep.com/patent/US20230273084A1 ## CPC - G01L 9/0054: {integral with a semiconducting diaphragm} - G01L 19/0627: {Protection against aggressive medium in general} - G01L 19/143: {Two part housings} - G01L 19/147: {Details about the mounting of the sensor to support or covering means} - G01L 19/148: {Details about the circuit board integration, e.g. integrated with the diaphragm surface or encapsulation} - G01L 27/00: Testing or calibrating of apparatus for measuring fluid pressure - G01L 27/007: {Malfunction diagnosis, i.e. diagnosing a sensor defect} - G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G) ## Abstract A pressure sensor device has: a pressure detection structure provided in a first die of semiconductor material; a package, configured to internally accommodate the pressure detection structure in an impermeable manner, the package having a base structure and a body structure, arranged on the base structure, with an access opening in contact with an external environment and internally defining a housing cavity, in which the first die is arranged covered with a coating material. A piezoelectric transduction structure, of a ultrasonic type, is accommodated in the housing cavity, in order to allow detection of foreign material above the coating material and within the package. In particular, the piezoelectric transduction structure is integrated in the first die, which comprises a first portion, wherein the pressure detection structure is integrated, and a second portion, separate and distinct from the first portion, wherein the piezoelectric transduction structure is integrated. ## Claims ### Claim 1 A device, comprising: a first die including: a pressure detection structure; and an ultrasonic piezoelectric transduction structure; a package contains the first die, the package including a base structure and a body structure on the base structure, the package having an access opening in fluid communication with an external environment, the package internally defining a housing cavity in which the first die is arranged and in which the first die is covered by a coating material within the package and in the housing cavity, wherein the piezoelectric transduction structure of the first die is configured to allow detection of foreign material on the coating material. ### Claim 2 (depends on 1) The device according to claim 1, wherein the first die further includes: a first portion at which the piezoelectric transduction structure is integrated; and a second portion separate and distinct from the first portion at which the piezoelectric transduction structure is integrated. ### Claim 3 (depends on 2) The device according to claim 2, wherein the piezoelectric transduction structure includes: a first membrane at a surface of the first die, arranged over a first cavity buried within the first die; a piezoelectric stack formed over the first membrane, the piezoelectric stack includes a first electrode, a piezoelectric material region and a second electrode, the piezoelectric material region being interposed between the first electrode and the second electrode and the first electrode being arranged on the surface of the first die. ### Claim 4 (depends on 3) The device according to claim 3, wherein said pressure detection structure includes: a second membrane at the surface of the first die, arranged over a second cavity buried within the first die; and detection elements of a piezoresistive type arranged in the second membrane and configured to allow detection of deformations of the second membrane due to impinging pressure waves. ### Claim 5 (depends on 3) The device according to claim 3, further comprising: a second die including processing circuitry, implemented as an ASIC (Application Specific Integrated Circuit), and the second die being in the housing cavity of the package, and wherein the processing circuit includes: a driving module for driving the piezoelectric transduction structure, configured to provide biasing signals to the first electrode and to the second electrode to deform the first membrane and generate ultrasound detection acoustic waves; and a detection module configured to read electrical signals transduced by the piezoelectric transduction structure when the second membrane is deformed by an echo due to reflection of the detection acoustic waves. ### Claim 6 (depends on 5) The device according to claim 5, wherein the detection module is configured to detect a presence of the foreign material in a portion of the housing cavity of the package interposed between the coating material and the access opening by processing characteristics of a detected signal detected through the piezoelectric detection structure due to the echo. ### Claim 7 (depends on 6) The device according to claim 6, wherein the detection module is configured to determine an acoustic impedance change associated with said foreign material. ### Claim 8 (depends on 6) The device according to claim 6, wherein the detection module is configured to: determine at least one of the following of an amplitude of peaks in the detected signal and the time position of the peaks with respect to an instant of generation of the detection acoustic waves; and determine the presence of the foreign material as a function of at least one of the of the following of the amplitude of the peaks the time position of the peaks. ### Claim 9 (depends on 5) The device according to claim 5, wherein the first and second dies are stacked, with a first surface of the second die coupled to a second surface of the first die by a bonding region. ### Claim 10 (depends on 1) The device according to claim 1, wherein the piezoelectric transduction structure includes: a plurality of cavities in the first die; a plurality of membranes arranged in a matrix or array at a surface of the first die, the plurality of membranes overlap the plurality of cavities; and a plurality of piezoelectric stacks at the surface of the first die, the plurality of piezoelectric stacks overlap the plurality of membranes. ### Claim 11 (depends on 1) The device according to claim 1, wherein: the coating material fills the housing cavity except a portion of the housing cavity, the portion of the housing cavity is in fluidic communication with the external environment through the access opening. ### Claim 12 A method, comprising: detecting foreign material with a pressure sensor device, the pressure sensor device including: a first die including: a pressure detection structure; and a piezoelectric transduction structure of an ultrasonic type; a package contains the first die, the package including a base structure and a body structure on the base structure, the package having an access opening in fluid communication with an external environment and internally defining a housing cavity in which the first die is arranged and in which the first die is covered with a coating material, wherein detecting the foreign material with the pressure sensor device includes: determining the presence of the foreign material over the coating material and within the package, determining the presence of the foreign material over the coating material and within the package including: generating ultrasounds detection acoustic waves with the piezoelectric transduction structure; and processing an electrical signal detected through the piezoelectric transduction structure due to an echo associated with a reflection of the detection acoustic waves. ### Claim 13 (depends on 11) The method according to claim 11, wherein processing the electrical signal detected through the piezoelectric transduction structure includes determining an acoustic impedance change associated with said foreign material. ### Claim 14 (depends on 13) The method according to claim 13, comprising determining the amplitude of peaks in the detected signal and/or the time position of the peaks with respect to an instant of generation of said detection acoustic waves; and determining the presence of said foreign material as a function of said amplitude of peaks and/or the time position of said peaks. ### Claim 15 A device, comprising: a base structure including a surface; a body structure coupled on the surface of the base structure, the body structure includes an access opening; a housing cavity defined by the base structure and the body structure; a first die within the housing cavity and on the surface of the base structure; a second die within the housing cavity and stacked on the second die, the second die including: a piezoelectric detection structure; and a piezoelectric transduction structure; a coating material in the housing cavity covers the first die and covers the second die, the coating material including a surface exposed by the access opening. ### Claim 16 (depends on 15) The device of claim 15, wherein the piezoelectric transduction structure is of an ultrasonic type. ### Claim 17 (depends on 15) The device of claim 15, wherein the second die further includes a surface facing way from the first die, the piezoelectric detection structure is at the surface of the first die, and the piezoelectric transduction structure is at the first surface. ### Claim 18 (depends on 15) The device of claim 15, wherein the piezoelectric transduction structure includes: a first cavity within the first die; a first membrane extends across the first cavity; and a piezoelectric stacked structure on the membrane. ### Claim 19 (depends on 18) The device of claim 18, wherein the piezoelectric stacked structure includes a first electrode on the membrane, a piezoelectric layer on the first electrode, and a second electrode on the piezoelectric layer. ### Claim 20 (depends on 19) The device of claim 19, wherein the piezoelectric detection structure includes: a second cavity in the first die and spaced apart from the first cavity; a second membrane extends across the second cavity; and a detection element in the first die and that overlaps the second membrane.