# US 12,180,065 B2 · Microelectromechanical system and process of making it > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,180,065 B2 - Document ID: US12180065B2 - Status: Granted - Kind: B2 - Application number: 17/214,954 - Filed: 2021-03-29 - Published: 2022-09-29 - Granted: 2024-12-31 - Earliest claimed: 2021-03-29 - Assignees: Aac Acoustic Technologies (Shenzhen) Co., Ltd. - Applicants: Aac Acoustic Technologies (Shenzhen) Co., Ltd. - Inventors: Euan James Boyd; Colin Robert Jenkins - Web page: https://patentgrep.com/patent/US12180065B2 ## CPC - B81B 3/0086: {Electrical characteristics, e.g. reducing driving voltage, improving resistance to peak voltage} - H04R 7/14: corrugated, pleated or ribbed - B81C 1/00698: {Electrical characteristics, e.g. by doping materials} - H04R 7/06: comprising a plurality of sections or layers - H04R 19/005: {using semiconductor materials} - H04R 19/04: Microphones (H04R19/01 takes precedence) - B81B 2201/0257: Microphones or microspeakers - B81B 2203/0127: Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function - B81B 2203/0315: Cavities - B81B 2203/0361: Tips, pillars - B81B 2203/04: Electrodes - B81C 2201/0133: Wet etching - H04R 2201/003: Mems transducers or their use - B81B: MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES (piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/00, H10N35/00) - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) - 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) ## Abstract A microelectromechanical system includes a lower membrane including a plurality of troughs and crests arranged alternately, an upper membrane including a plurality of troughs and crests arranged alternately, and a spacer layer disposed between the lower membrane and the upper membrane. The spacer layer includes counter electrode walls and support walls made of nitride, the counter electrode walls being provided with conductive elements. Chambers are formed between the troughs of the lower membrane and the crest of the upper membrane and the counter electrode walls are suspended in the chambers respectively. The support walls are sandwiched between the crests of the lower membrane and the troughs of the upper membrane with a space formed between adjacent support walls. The spaces between adjacent support walls may be empty or filled with oxide. Unwanted capacitance between the upper and lower membranes is reduced significantly. ## Claims ### Claim 1 A microelectromechanical system comprising: an electrically conductive lower membrane; the lower membrane comprises a plurality of troughs and crests arranged alternately; an electrically conductive upper membrane; the upper membrane comprising a plurality of troughs and crests arranged alternately; the trough of the lower membrane are aligned with the crests of the upper membrane respectively while the crests of the lower membrane are aligned with the trough of the upper membrane respectively; and a spacer layer disposed between the lower membrane and the upper membrane, the spacer layer comprising counter electrode walls and support walls, the counter electrode walls being provided with conductive elements; wherein a chamber is formed between aligned one trough of the lower membrane and one crest of the upper membrane; chambers are respectively formed between aligned troughs of the lower membrane and crests of the upper membrane; the counter electrode walls are suspended in the chambers respectively; and the support walls are respectively sandwiched between the crests of the lower membrane and the troughs of the upper membrane; and a space is formed between aligned one crest of the lower membrane and one trough of the upper membrane and located between two adjacent support walls, and spaces are respectively formed between the crests of the lower membrane and the troughs of the upper membrane. ### Claim 2 (depends on 1) The microelectromechanical system of claim 1, wherein the counter electrode walls and support walls are made of a first material, and the space is filled with a second material having a dielectric constant less than that of the first material. ### Claim 3 (depends on 2) The microelectromechanical system of claim 2, wherein the first material is silicon nitride. ### Claim 4 (depends on 2) The microelectromechanical system of claim 2, wherein the second material is silicon oxide. ### Claim 5 (depends on 1) The microelectromechanical system of claim 1, wherein the chambers are isolated from adjacent spaces by corresponding support walls. ### Claim 6 (depends on 1) The microelectromechanical system of claim 1, wherein one or both of aligned crest of the upper membrane and trough of the lower membrane define a through hole communicating the chamber with outside of the chamber. ### Claim 7 (depends on 6) The microelectromechanical system of claim 6, wherein one or both of aligned crest of the lower membrane and trough of the upper membrane defines a through hole communicating the space with outside of the space. ### Claim 8 (depends on 1) The microelectromechanical system of claim 1, wherein the lower membrane is made of electrically conductive material or comprises an insulating membrane with conductive elements provided thereon; and/or the upper membrane is made of electrically conductive material or comprises an insulating membrane with conductive elements provided thereon.