{
  "patent_number": "US 10578505",
  "country": "US",
  "title": "How to Build a Tiny Pressure Sensor Inside a Silicon Chip",
  "original_title": "Process for manufacturing a MEMS pressure sensor, and corresponding MEMS pressure sensor",
  "summary": "This patent describes a method for building a tiny pressure sensor, called a MEMS sensor, directly inside a silicon chip, where a flexible membrane and a plate form a capacitor that changes with pressure.",
  "what_it_does": "This patent details a process for manufacturing a MEMS pressure sensor. It starts by creating a 'buried cavity' entirely within a silicon substrate (Claim 1). A 'membrane' is then suspended above this cavity (Claim 1). Next, a 'conductive layer comprising a plate' made of polysilicon is formed above the membrane, separated by an 'empty space' (Claim 1). This empty space is created by growing the polysilicon layer on a temporary 'sacrificial layer,' then etching 'through holes' in the polysilicon and removing the sacrificial material through these holes (Claim 1). An 'access channel' is formed to allow outside air pressure to reach the membrane (Claim 1). Finally, 'electrical-contact elements' are created to connect to the membrane and the plate, which together form a 'sensing capacitor' whose electrical capacitance changes as pressure flexes the membrane (Claim 1). For example, a smartphone might use such a sensor to detect changes in altitude by measuring atmospheric pressure.",
  "what_it_does_not_cover": [
    "Does not cover pressure sensors that do not rely on changes in capacitance (e.g., piezoresistive sensors).",
    "Does not cover sensors where the cavity is not 'fully enclosed buried within the body' of the semiconductor material (Claim 8).",
    "Does not cover manufacturing processes that do not use a sacrificial layer and through-holes to create the empty space between the membrane and the plate (Claim 1).",
    "Does not cover sensors where the suspended plate is not made of polysilicon (Claim 1, 8).",
    "Does not cover sensors where the fluidic communication to the membrane is not provided by 'a plurality of through holes in the layer of polysilicon' (Claim 8)."
  ],
  "filed": "2018-04-20",
  "granted": "2020-03-03",
  "expires": "2038-04-20",
  "status": "active",
  "holder": "STMicroelectronics SRL",
  "holder_url": "https://patentbrief.org/company/stmicroelectronics-srl",
  "inventors": [
    {
      "name": "Sarah Zerbini",
      "url": "https://patentbrief.org/inventor/sarah-zerbini"
    },
    {
      "name": "Enri Duqi",
      "url": "https://patentbrief.org/inventor/enri-duqi"
    },
    {
      "name": "Lorenzo Baldo",
      "url": "https://patentbrief.org/inventor/lorenzo-baldo"
    }
  ],
  "times_cited": 1,
  "tags": [
    "consumer_electronics",
    "semiconductors",
    "telecommunications",
    "automotive",
    "medical"
  ],
  "abstract": "A process for manufacturing a MEMS pressure sensor having a micromechanical structure envisages: providing a wafer having a substrate of semiconductor material and a top surface; forming a buried cavity entirely contained within the substrate and separated from the top surface by a membrane suspended above the buried cavity; forming a fluidic-communication access for fluidic communication of the membrane with an external environment, set at a pressure the value of which has to be determined; forming, suspended above the membrane, a plate made of polysilicon, separated from the membrane by an empty space; and forming electrical-contact elements for electrical connection of the membrane and of the plate, which are designed to form the plates of a sensing capacitor, the value of capacitance of which is indicative of the value of pressure to be detected. A corresponding MEMS pressure sensor having the micromechanical structure is moreover described.",
  "url": "https://patentbrief.org/patent/us/10578505/process-for-manufacturing-a-mems-pressure-sensor-and-corresponding-mems-pressure",
  "markdown_url": "https://patentbrief.org/patent/us/10578505/process-for-manufacturing-a-mems-pressure-sensor-and-corresponding-mems-pressure/md",
  "google_patents_url": "https://patents.google.com/patent/US10578505",
  "relatedPatents": []
}