# US 6,281,033 B1 · Semiconductor dynamic quantity-sensor and method of manufacturing the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,281,033 B1 - Document ID: US6281033B1 - Status: Granted - Kind: B1 - Application number: 09/471,712 - Filed: 1999-12-23 - Granted: 2001-08-28 - Earliest claimed: 1998-12-24 - Assignees: Fuji Electric Co., Ltd. - Inventors: Katsumichi Uayanagi; Mitsuo Sasaki; Mutsuo Nishikawa; Shiho Katsumi - Web page: https://patentgrep.com/patent/US6281033B1 ## CPC - B81C 1/00928: {Eliminating or avoiding remaining moisture after the wet etch release of the movable structure} - B81B 3/0005: {Anti-stiction coatings} - G01P 15/0802: {Details} - G01P 15/123: {by piezo-resistive elements, e.g. semiconductor strain gauges} - B81B 2201/0235: Accelerometers - B81C: PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS (making microcapsules or microballoons B01J13/02; processes or apparatus specially adapted for the manufacture or treatment of piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/01) - B81B: MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES (piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/00, H10N35/00) - G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G}) ## Abstract A method and apparatus for manufacturing a semiconductor physical quantity sensor according to the present invention achieves the high sensing accuracy and reliability and prevents a sticking phenomenon. Specifically, a semiconductor physical quantity sensor is cleaned by a displacement liquid and is dried while a SOI substrate is revolving. The number of revolutions is determined so that a suction force (Fs), which acts on a silicon substrate by a surface tension of the displacement liquid, a sensor spring force FK and a centrifugal force (Fr) generated by the acceleration in the revolution can satisfy the following condition: (FK+Fr)>FS. In order to prevent the sticking phenomenon after the stop of the spray, the semiconductor physical quantity sensor is dried by spraying an inert gas such as nitrogen including minus ions so that the revolving SOI substrate can eliminate static electricity generated by friction of the air flow. ## Claims ### Claim 1 A semiconductor physical quantity sensor manufacturing method using a SOI substrate composed of a silicon substrate as a first layer, an insulating layer as a second sacrifice layer formed on said first layer, and a silicon or polysilicon layer as a third layer formed on said second layer, wherein said third layer is machined to form a sensing element for sensing physical quantities and removing said second layer to form a semiconductor physical quantity sensor, said method comprising the steps of: coating said third layer with protective film; forming a sensing element by using said protective film as a mask; removing said second sacrifice layer by wet etching; substituting an etching liquid used in said wet etching with a displacement liquid; drying said sensing element by removing said displacement liquid sticking on said sensing element in a state wherein an acceleration in an opposite direction to a direction toward said first layer is applied to said sensing element; and removing said protective film by dry etching. ### Claim 2 (depends on 1) The semiconductor physical quantity sensor manufacturing method as defined in claim 1, further comprising the step of obtaining the acceleration to be applied to said sensing element by a centrifugal force generated by revolving said SOI substrate. ### Claim 3 (depends on 2) The semiconductor physical quantity sensor manufacturing method as defined in claim 2, further comprising the step of drying said sensing element so that a suction force (FS) of said sensing element against said first layer due to a surface tension of said displacement liquid, said centrifugal force (Fr) and a spring force FK of said sensing element can satisfy the following condition: (Fr+FK)>FS. ### Claim 4 (depends on 3) The semiconductor physical quantity sensor manufacturing method as defined in claim 3, further comprising the steps of sticking said displacement liquid on said sensing element until said acceleration reaches a predetermined value, and removing said displacement liquid and drying said sensing element after said acceleration reaches said predetermined value. ### Claim 5 (depends on 1) The semiconductor physical quantity sensor manufacturing method as defined in claim 1, further comprising the step of drying said sensing element with an inert gas. ### Claim 6 (depends on 3) The semiconductor physical quantity sensor manufacturing method as defined in claim 3, further comprising the step of drying said sensing element with an inert gas. ### Claim 7 (depends on 4) The semiconductor physical quantity sensor manufacturing method as defined in claim 4, further comprising the step of drying said sensing element with an inert gas. ### Claim 8 (depends on 2) The semiconductor physical quantity sensor manufacturing method as defined in claim 2, further comprising the step of electrically connecting said first layer with said second layer and revolving said SOI substrate. ### Claim 9 (depends on 1) The semiconductor physical quantity sensor manufacturing method as defined in claim 1, wherein said displacement liquid is vapor, pure water or isopropyl alcohol (IPA). ### Claim 10 (depends on 3) The semiconductor physical quantity sensor manufacturing method as defined in claim 3, wherein said displacement liquid is vapor, pure water or isopropyl alcohol (IPA). ### Claim 11 (depends on 4) The semiconductor physical quantity sensor manufacturing method as defined in claim 4, wherein said displacement liquid is vapor, pure water or isopropyl alcohol (IPA).