# US 8,542,850 B2 · Miniature microphone assembly with hydrophobic surface coating > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,542,850 B2 - Document ID: US8542850B2 - Status: Granted - Kind: B2 - Application number: 12/231,398 - Filed: 2008-09-02 - Published: 2009-03-12 - Granted: 2013-09-24 - Earliest claimed: 2007-09-12 - Assignees: Epcos PTE Ltd. - Applicants: Christian Wang; Jörg Rehder; Leif Steen Johansen; Peter Ulrik Scheel - Inventors: Christian Wang; Jörg Rehder; Leif Steen Johansen; Peter Ulrik Scheel - Web page: https://patentgrep.com/patent/US8542850B2 ## CPC - H04R 31/00: Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor {(manufacture of microstructural arrangements of deformable or non-deformable structures in general B81C1/00182)} - H04R 19/005: {using semiconductor materials} - H04R 19/04: Microphones (H04R19/01 takes precedence) - H04R 31/006: {Interconnection of transducer parts (of diaphragm and outer suspension by moulding H04R31/003)} - Y10T 29/49005: Acoustic transducer - 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) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A miniature microphone assembly comprises a capacitive-microphone transducer, a microphone carrier, and an integrated circuit die. The capacitive-microphone transducer includes a microphone-electrical contact or terminal. The microphone carrier comprises a carrier electrical contact or terminal formed on a first surface of the microphone carrier. An integrated circuit die includes a die electrical terminal operatively coupled to signal amplification or signal conditioning circuitry of the integrated circuit die. The first surface of the microphone carrier comprises a hydrophobic layer or coating. The side surfaces of the integrated circuit die and/or the capacitive-microphone transducer may also include the hydrophobic layer or coating. ## Claims ### Claim 1 A miniature microphone assembly comprising: a capacitive microphone transducer comprising a transducer electrical terminal; a microphone carrier comprising a carrier electrical terminal formed on a first surface thereof; an integrated circuit die comprising a die electrical terminal operatively coupled to signal amplification or signal conditioning circuitry of the integrated circuit die; and wherein the first surface of the microphone carrier comprises a hydrophobic layer or coating and wherein the hydrophobic layer or coating is solely comprised of a self-assembled molecular monolayer in direct exposure to moisture to protect the first surface of the microphone carrier. ### Claim 2 (depends on 1) A miniature microphone assembly according to claim 1, wherein the integrated circuit die comprises a die surface with a hydrophobic coating. ### Claim 3 (depends on 1) A miniature microphone assembly according to claim 1, wherein the capacitive microphone transducer comprises a condenser element or electret element. ### Claim 4 (depends on 1) A miniature microphone assembly according to claim 1, wherein the microphone carrier comprises first and second carrier electrical contacts separated by a distance of less than 1000 μm. ### Claim 5 (depends on 4) A miniature microphone assembly according to claim 4, wherein the first and second carrier electrical contacts have a DC voltage difference larger than 0.5 Volt, in an operational state of the miniature microphone assembly. ### Claim 6 (depends on 4) A miniature microphone assembly according to claim 4, wherein the first and second carrier electrical contacts comprise: a first terminal electrically connected to the die electrical terminal of the integrated circuit die; and a second terminal electrically connected to a ground line or DC voltage supply line. ### Claim 7 (depends on 6) A miniature microphone assembly according to claim 6, wherein the second terminal comprises an electrically conductive sealing ring disposed in-between the capacitive microphone transducer and the microphone carrier. ### Claim 8 (depends on 1) A miniature microphone assembly according to claim 1, wherein a capacitance of the capacitive microphone transducer is less than 20 pF. ### Claim 9 (depends on 1) A miniature microphone assembly according to claim 1, wherein the hydrophobic coating is chemically bound to at least one of the surface of the microphone carrier or the die surface of the integrated circuit. ### Claim 10 (depends on 1) A miniature microphone assembly according to claim 1, wherein the hydrophobic coating has a contact angle for water between 90° and 130°. ### Claim 11 (depends on 1) A miniature microphone assembly according to claim 1, wherein the capacitive microphone transducer comprises a diaphragm member and a back-plate member and first and second transducer electrical terminals electrically coupled to the diaphragm and back-plate members, respectively. ### Claim 12 (depends on 11) A miniature microphone assembly according to claim 11, wherein the back-plate member comprises a perforated back-plate member adjacently positioned to the diaphragm member, and the diaphragm member comprises a through-going opening allowing molecules of the hydrophobic layer to travel through the opening and the perforated back-plate structure. ### Claim 13 (depends on 1) A miniature microphone assembly according to claim 1, wherein the capacitive microphone transducer and integrated circuit die are attached to, and electrically connected to, the microphone carrier and electrically interconnected by electrical traces formed on or in the microphone carrier. ### Claim 14 (depends on 13) A miniature microphone assembly according to claim 13, wherein the capacitive microphone transducer is located above the microphone carrier with a microphone electrical contact aligned with a first carrier electrical contact. ### Claim 15 (depends on 1) A miniature microphone assembly according to claim 1, wherein the microphone carrier comprises: a second and substantially planar surface arranged oppositely to the first surface, the second surface comprising a plurality of microphone electrical contacts to allow surface mounting of the condenser microphone assembly to an external circuit board. ### Claim 16 (depends on 1) A miniature microphone assembly according to claim 1, further comprising an underfill agent deposited in a space between the microphone carrier and the capacitive microphone transducer. ### Claim 17 (depends on 1) A portable communication device comprising a miniature microphone assembly according to claim 1, said portable communication device being selected from the group consisting of mobile phones, head-sets, in-ear monitors, hearing prostheses or hearing aids, game consoles, portable computers, and any combination thereof. ### Claim 18 A method of manufacturing a miniature microphone assembly, the method comprising: providing a microphone carrier comprising a carrier electrical terminal formed on a first surface of the microphone carrier; providing a capacitive microphone transducer comprising a transducer electrical terminal; providing an integrated circuit die comprising a die electrical terminal operatively coupled to signal amplification or signal conditioning circuitry of the integrated circuit die; attaching the capacitive microphone transducer and the integrated circuit die to the first surface of the microphone carrier; electrically interconnecting the transducer electrical terminal and the die electrical terminal through electrical traces formed on or in the microphone carrier; placing the miniature microphone assembly in a vapour phase deposition chamber or liquid phase deposition container; and depositing a hydrophobic layer or coating onto the first surface of the microphone carrier, wherein the deposited hydrophobic layer or coating is solely comprised of a self-assembled molecular monolayer exposed directly to moisture to protect the first surface of the microphone carrier. ### Claim 19 (depends on 18) A method of manufacturing a miniature microphone assembly according to claim 18, further comprising: depositing an underfill agent in a space between the microphone carrier and the capacitive microphone transducer. ### Claim 20 (depends on 19) A method of manufacturing a miniature microphone assembly according to claim 19, further comprising: depositing the underfill agent in a space between respective sidewalls of the capacitive microphone transducer and the integrated circuit die. ### Claim 21 (depends on 18) A method of manufacturing a miniature microphone assembly according to claim 18, wherein: the capacitive microphone transducer comprises a perforated back-plate member and an adjacently positioned diaphragm member; and the diaphragm member comprises a through-going opening allowing molecules of the hydrophobic layer to travel through the opening and the perforated back-plate member. ### Claim 22 (depends on 11) The miniature microphone assembly according to claim 11, wherein the hydrophobic self-assembled molecular monolayer extends to cover at least a portion of the surface of the carrier which is positioned underneath the capacitive microphone transducer, and to cover at least a portion of a surface of the microphone transducer that faces the portion of the surface of the carrier positioned underneath the transducer. ### Claim 23 (depends on 1) The miniature microphone assembly according to claim 1, wherein the hydrophobic self-assembled molecular monolayer is disposed on a region of the surface of the carrier between the die electrical terminal and the transducer electrical terminal to inhibit formation of an electrically conductive moisture film thereby preventing a parasitic leakage current from flowing between the transducer electrical terminal and the die electrical terminal via the moisture film.