# US 9,439,017 B2 · Method for manufacturing a plurality of microphone structures, microphone and mobile device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,439,017 B2 - Document ID: US9439017B2 - Status: Granted - Kind: B2 - Application number: 14/176,182 - Filed: 2014-02-10 - Published: 2015-08-13 - Granted: 2016-09-06 - Earliest claimed: 2014-02-10 - Assignees: Infineon Technologies AG - Applicants: Infineon Technologies AG - Inventors: Ursula Hedenig; Daniel Maurer; Thomas Grille; Peter Irsigler; Soenke Pirk; Andre Brockmeier - Web page: https://patentgrep.com/patent/US9439017B2 ## 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 23/00: Transducers other than those covered by groups H04R9/00 - H04R21/00 {(diaphragms for transducers of the distributed-mode type H04R7/045)} - H04R 2201/003: Mems transducers or their use - Y10T 29/49: Method of mechanical manufacture - 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 In various embodiments, a method for manufacturing microphone structures is provided. The method may include: Providing a substrate having a front side and a back side, the backside facing away from the front side, and having an inner area and an outer area laterally surrounding the inner area, with the inner area comprising a plurality of microphone areas each microphone are being provided for one microphone of the plurality of microphones; Forming a plurality of layers for the plurality of microphones in the microphone areas on the front side of the substrate; Forming a recess from the backside of the substrate with the recess laterally overlapping the entire inner area; Forming a plurality of cavities into a bottom of the recess with each cavity of the plurality of cavities being formed in one of the microphone areas; Processing the layers to form the plurality of microphone structures, wherein each microphone structure comprises at least one layer of the plurality of layers and one cavity; and Separating the plurality of microphone structures from each other. ## Claims ### Claim 1 A method for manufacturing a plurality of microphone structures, the method comprising: providing a substrate having a front side and a backside, the backside facing away from the front side, and having an inner area and an outer area laterally surrounding the inner area, with the inner area comprising a plurality of microphone areas, each microphone area being provided for one microphone of the plurality of microphones; forming a plurality of layers for the plurality of microphones in the microphone areas on the front side of the substrate; forming a recess from the backside of the substrate with the recess laterally overlapping the entire inner area; forming a plurality of cavities into a bottom of the recess with each cavity of the plurality of cavities being formed in one of the microphone areas; processing the layers to form the plurality of microphone structures, wherein each microphone structure comprises at least one layer of the plurality of layer and one cavity; and separating the plurality of microphone structures from each other. ### Claim 2 (depends on 1) The method of claim 1, wherein the substrate has a first thickness in the inner area in the recess, wherein the substrate has a second thickness in the outer area outside the recess, and wherein the second thickness is larger than the first thickness. ### Claim 3 (depends on 2) The method of claim 2, wherein the recess is formed such that the first thickness is in a range from about 20 μm to about 400 μm. ### Claim 4 (depends on 1) The method of claim 1, wherein, before the recess is formed, the substrate is thinned such that the substrate has the same thickness. ### Claim 5 (depends on 2) The method of claim 2, wherein the second thickness is in a range from about 300 μm to about 900 μm. ### Claim 6 (depends on 1) The method of claim 1, wherein the cavities are formed by a wet chemical etching process. ### Claim 7 (depends on 6) The method of claim 6, wherein, before the wet chemical etching process, an alkaline resistant photosensitive layer or a hardmask layer structured by a photosensitive layer is provided on the bottom of the recess, an exposure mask is arranged on the backside of the substrate such that the mask is in direct contact with the substrate in the outer area and that there is a given distance between the mask and the bottom in the inner area, wherein the mask comprises a plurality of mask recesses each corresponding to one cavity of the plurality of cavities to be formed in the substrate, and wherein the photosensitive layer or the hardmask layer structured by a photosensitive layer is exposed through the mask recesses of the mask. ### Claim 8 (depends on 1) The method of claim 1, wherein the cavities are formed such that each cavity comprises a circumferential slant, wherein an angle of the slant ranges from about 0° to 90°. ### Claim 9 A method for manufacturing a plurality of micro-electro-mechanical system microphones, the method comprising: providing a semiconductor substrate having a first side and a second side, the second side facing away from the first side, and having an inner area and an outer area laterally surrounding the inner area with the inner area having a plurality of microphone areas and an outer area laterally surrounding the microphone areas; forming a layer structure over the first side of the semiconductor substrate in the microphone areas; forming a recess from the second side of the substrate with the recess laterally overlapping the entire inner area; forming at least one cavity in the substrate in each microphone area; processing the layer structure to provide at least one micro-electro-mechanical system microphone in each microphone area; and separating the micro-electro-mechanical system microphones from each other. ### Claim 10 (depends on 9) The method of claim 9, wherein the substrate has a first thickness in the microphone areas and a second thickness in the peripheral area. ### Claim 11 (depends on 10) The method of claim 10, wherein the recess is formed such that the first thickness is in a range from about 20 μm to about 400 μm. ### Claim 12 (depends on 9) The method of claim 9, wherein, before the recess is formed, the substrate is thinned such that the substrate has the same thickness. ### Claim 13 (depends on 10) The method of claim 10, wherein the second thickness is in a range from about 300 μm to about 900 μm. ### Claim 14 (depends on 9) The method of claim 9, wherein the cavities are formed by a wet chemical etching process or by an anisotropic dry etching process. ### Claim 15 (depends on 14) The method of claim 14, wherein, before the wet chemical etching process, an alkaline resistant photosensitive layer or hardmask is provided on the substrate in the recess, an exposure mask is arranged on the second side of the substrate such that the mask is in direct contact with the peripheral area of the substrate and that there is a given distance between the mask and the substrate in the recess, wherein the mask comprises a plurality of mask openings each corresponding to one of the cavities to be formed in the substrate, and wherein the alkaline resistant photosensitive layer or the photosensitive layer on the hardmask is exposed through the mask openings of the mask. ### Claim 16 (depends on 9) The method of claim 9, wherein the cavities are formed such that each cavity comprises a circumferential slant, in which the thickness of the substrate increases from zero to a first thickness, wherein an angle of the slant ranges from about 0° to 90°.