# US 2010/0164028 A1 · Semiconductor pressure sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0164028 A1 - Document ID: US20100164028A1 - Status: Published application - Kind: A1 - Application number: 12/722,079 - Filed: 2010-03-11 - Published: 2010-07-01 - Earliest claimed: 2007-09-25 - Assignees: Alps Electric Co., Ltd. - Inventors: Takuya Adachi; Katsuya Kikuiri; Tetsuya Fukuda; Hisanobu Okawa; Takayuki Minagawa - Web page: https://patentgrep.com/patent/US20100164028A1 ## CPC - H10D 48/50: Devices controlled by mechanical forces, e.g. pressure - G01L 9/0042: {Constructional details associated with semiconductive diaphragm sensors, e.g. etching, or constructional details of non-semiconductive diaphragms (details about the integration or bonding of piezoresistor in or on the diaphragm G01L9/0052 and G01L9/0057 respectively)} - G01L 9/0054: {integral with a semiconducting diaphragm} - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES - G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G) ## Abstract A semiconductor pressure sensor includes a cavity disposed in one silicon substrate of a SOI substrate having two silicon substrates bonded to each other with an oxide film therebetween and a diaphragm formed from the other silicon substrate and the oxide film, wherein the oxide film, bordering the cavity, of the diaphragm includes an arc-shaped section at the boundary portion to the one silicon substrate defining the inner wall side surface of the cavity, the arc-shaped section having the same diameter as the diameter of the cavity in the one silicon substrate and reducing the cavity diameter from the boundary portion toward the diaphragm center. ## Claims ### Claim 1 A semiconductor pressure sensor comprising: a cavity disposed in one silicon substrate of a SOI substrate having two silicon substrates bonded to each other with an oxide film therebetween; and a diaphragm formed from the other silicon substrate and the oxide film, wherein the oxide film, bordering the cavity, of the diaphragm includes an arc-shaped section at the boundary portion to the one silicon substrate defining the inner wall side surface of the cavity, the arc-shaped section having the same diameter as the diameter of the cavity in the one silicon substrate and reducing the cavity diameter from the boundary portion toward the diaphragm center, and an arc-shaped section of the one silicon substrate and the arc-shaped section of the oxide film of the diaphragm are disposed continuously at the boundary portion. ### Claim 2 (depends on 1) The semiconductor pressure sensor according to claim 1, wherein the oxide film, bordering the cavity, of the diaphragm has a thickness reducing from the boundary portion toward the central portion of the diaphragm and has a region with a small thickness. ### Claim 3 (depends on 1) The semiconductor pressure sensor according to claim 1, wherein the cavity is rectangular in the plan view. ### Claim 4 (depends on 1) The semiconductor pressure sensor according to claim 1, wherein the arc-shaped section is disposed all around the boundary portion of the cavity. ### Claim 5 (depends on 1) The semiconductor pressure sensor according to claim 1, wherein on the diaphragm portion of the SOI substrate, sensitive resistance elements are disposed along the outline of the diaphragm in such a way as to constitute a bridge circuit. ### Claim 6 (depends on 1) The semiconductor pressure sensor according to claim 1, wherein the inner wall side surface of the cavity is disposed almost perpendicularly to the diaphragm. ### Claim 7 (depends on 1) The semiconductor pressure sensor according to claim 1, wherein the sensitive resistance element is a piezo-resistance element having a resistance value changing in accordance with distortion of the diaphragm. ### Claim 8 A semiconductor pressure sensor comprising: a cavity disposed through digging in one silicon substrate of a SOI substrate having two silicon substrates bonded to each other with an oxide film therebetween; and a diaphragm formed from the other silicon substrate and the oxide film, wherein periodic unevenness is disposed, in the digging direction, on an inner wall surface of the cavity in the one silicon substrate, the oxide film, bordering the cavity, of the diaphragm includes an arc-shaped section at the boundary portion to the one silicon substrate defining the inner wall side surface of the cavity, the arc-shaped section having the same diameter as the diameter of the cavity in the one silicon substrate and reducing the cavity diameter from the boundary portion toward the diaphragm center, and the arc-shaped section is disposed continuously from the uneven section of the one silicon substrate. ### Claim 9 (depends on 8) The semiconductor pressure sensor according to claim 8, wherein the oxide film, bordering the cavity, of the diaphragm has a thickness reducing from the boundary portion toward the central portion of the diaphragm and has a region with a small thickness. ### Claim 10 (depends on 8) The semiconductor pressure sensor according to claim 8, wherein the cavity is rectangular in the plan view. ### Claim 11 (depends on 8) The semiconductor pressure sensor according to claim 8, wherein the arc-shaped section is disposed all around the boundary portion of the cavity. ### Claim 12 (depends on 8) The semiconductor pressure sensor according to claim 8, wherein on the diaphragm portion of the SOI substrate, sensitive resistance elements are disposed along the outline of the diaphragm in such a way as to constitute a bridge circuit. ### Claim 13 (depends on 8) The semiconductor pressure sensor according to claim 8, wherein the inner wall side surface of the cavity is disposed almost perpendicularly to the diaphragm. ### Claim 14 (depends on 8) The semiconductor pressure sensor according to claim 8, wherein the sensitive resistance element is a piezo-resistance element having a resistance value changing in accordance with distortion of the diaphragm.