# US 2015/0316436 A1 · Vertical membranes for pressure sensing applications > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2015/0316436 A1 - Document ID: US20150316436A1 - Status: Published application - Kind: A1 - Application number: 14/269,052 - Filed: 2014-05-02 - Published: 2015-11-05 - Earliest claimed: 2014-05-02 - Assignees: Silicon Microstructures, Inc. - Applicants: Silicon Microstructures, Inc. - Inventors: Holger Doering - Web page: https://patentgrep.com/patent/US20150316436A1 ## CPC - G01L 9/0047: {Diaphragm with non uniform thickness, e.g. with grooves, bosses or continuously varying thickness} - G01L 9/0051: {using variations in ohmic resistance} - G01L 19/0618: {Overload protection} - G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G) ## Abstract Pressure sensors having vertical diaphragms or membranes. A vertical diaphragm may be located in a first silicon wafer between a first and second cavity, where the first and second cavities are covered by a second silicon wafer. One or more active or passive devices or components may be located on a top of the vertical diaphragm. ## Claims ### Claim 1 A pressure sensor comprising: a first portion formed of a first silicon wafer and having a first cavity and a second cavity in a top side such that a vertical membrane is formed between the first cavity and the second cavity; a second portion formed of a second silicon wafer and having a bottom side contacting the top side of the first portion such that the first cavity is sealed to form a reference cavity, a passage through the first portion from a bottom side of the first portion to the second cavity such that the second cavity forms a pressurized cavity; a first device formed in a top side of the second portion over the vertical membrane; and a second device formed in the top side of the second portion over the vertical membrane. ### Claim 2 (depends on 1) The pressure sensor of claim 1 wherein the first device and the second device are used to measure a pressure in the pressurized cavity relative to a pressure in the reference cavity. ### Claim 3 (depends on 2) The pressure sensor of claim 2 wherein the first device and the second device are resistors. ### Claim 4 (depends on 2) The pressure sensor of claim 2 further comprising an oxide layer between the first portion and the second portion. ### Claim 5 A pressure sensor comprising: a first portion formed of a first silicon wafer and having a first etched recess and a second etched recess formed in a top side such that a vertical membrane is formed between the first etched recess and the second etched recess; a second portion formed of a second silicon wafer and having a bottom side contacting the top side of the first portion such that a first cavity is defined by the first etched recess and a bottom of the second portion and a second cavity is defined by the second etched recess and a bottom of the second portion; a first passage through the second portion from a top side of the second portion to the first cavity such that the first cavity forms a first pressurized cavity; and a first device formed in a top side of the second portion over the vertical membrane. ### Claim 6 (depends on 5) The pressure sensor of claim 5 wherein the second portion seals the second etched recess such that the second cavity is a reference cavity. ### Claim 7 (depends on 6) The pressure sensor of claim 6 wherein the first device is used to measure a pressure in the first pressurized cavity relative to the reference cavity. ### Claim 8 (depends on 7) The pressure sensor of claim 7 wherein the first device is a resistor. ### Claim 9 (depends on 8) The pressure sensor of claim 8 wherein the resistor includes a p-type region extending through the second portion into the vertical membrane in the first portion. ### Claim 10 (depends on 5) The pressure sensor of claim 5 further comprising a second passage through the first portion from a bottom of the first portion to the second cavity to form a second pressurized cavity. ### Claim 11 (depends on 10) The pressure sensor of claim 10 wherein the first device is used to measure a pressure in the first pressurized cavity relative to the second pressurized cavity. ### Claim 12 (depends on 11) The pressure sensor of claim 11 wherein first device is a resistor. ### Claim 13 (depends on 12) The pressure sensor of claim 12 wherein the resistor includes a p-type region extending through the second portion into the vertical membrane in the first portion. ### Claim 14 (depends on 10) The pressure sensor of claim 10 wherein the pressure sensor is a differential pressure sensor. ### Claim 15 A pressure sensor comprising: a first vertical membrane between a first cavity and a second cavity; the first cavity formed by a first recess formed in a top of a first wafer, the first recess covered by a bottom of a second wafer; the second cavity formed by a second recess formed in the top of the first wafer, the second recess covered by the bottom of the second wafer; and a first device formed in a top surface of the second wafer. ### Claim 16 (depends on 15) The pressure sensor of claim 15 further comprising an oxide layer between the first wafer and the second wafer. ### Claim 17 (depends on 16) The pressure sensor of claim 16 wherein the first wafer is fusion bonded to the second wafer. ### Claim 18 (depends on 17) The pressure sensor of claim 17 wherein the first device is a resistor. ### Claim 19 (depends on 18) The pressure sensor of claim 18 wherein the resistor is located over the vertical membrane. ### Claim 20 (depends on 18) The pressure sensor of claim 18 wherein the resistor is one of a plurality of resistors located over the vertical membrane. ### Claim 21 (depends on 20) The pressure sensor of claim 20 wherein the resistor includes a p-type region extending through the second wafer into the vertical membrane in the first wafer. ### Claim 22 (depends on 18) The pressure sensor of claim 18 further comprising a first passage through the second wafer from a top of the second wafer to the first cavity. ### Claim 23 (depends on 22) The pressure sensor of claim 22 further comprising a second passage through the first wafer from a bottom of the first wafer to the second cavity. ### Claim 24 (depends on 15) The pressure sensor of claim 15 further comprising a boss in the first cavity extending from a wall of the first cavity opposing the vertical membrane and extending towards the vertical membrane such that a deflection of the vertical membrane may be limited. ### Claim 25 A pressure sensor comprising: a first wafer having a first recess and a second recess etched in a top side such that a vertical membrane is formed between the first recess and the second recess, wherein the vertical membrane has a first lateral portion and a second lateral portion, the first lateral portion thicker than the second lateral portion; and a second wafer having a bottom side attached to the top side of first wafer such that a first cavity is formed by the first recess and the bottom of the second wafer and a second cavity is formed by the second recess and the bottom of the second wafer. ### Claim 26 (depends on 25) The pressure sensor of claim 25 further comprising a first passage through the second wafer from a top of the second wafer to the first cavity. ### Claim 27 (depends on 25) The pressure sensor of claim 25 further comprising a first device over the first lateral portion and a second device over the second lateral portion. ### Claim 28 (depends on 27) The pressure sensor of claim 27 wherein the first device and the second device comprise resistors. ### Claim 29 (depends on 28) The pressure sensor of claim 28 wherein the resistors each include a p-type region extending through the second wafer into the vertical membrane in the first wafer.