Source: http://www.google.com/patents/US20080232615?ie=ISO-8859-1
Timestamp: 2015-07-06 23:39:28
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Matched Legal Cases: ['art 30', 'art 30', 'art 30', 'art 29', 'art 30', 'art 30', 'art 30', 'art 30', 'art 30', 'art 30']

Patent US20080232615 - Condenser microphone chip - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsDisclosed is a condenser microphone chip, comprising: a substrate (21); a diaphragm (26) spaced from the substrate; a curved beam (27) connected with the diaphragm (26) to anchor the diaphragm (26) to the substrate (21); a curved beam connecting part (29) having a shape of a substantially circular plate....http://www.google.com/patents/US20080232615?utm_source=gb-gplus-sharePatent US20080232615 - Condenser microphone chipAdvanced Patent SearchPublication numberUS20080232615 A1Publication typeApplicationApplication numberUS 11/929,242Publication dateSep 25, 2008Filing dateOct 30, 2007Priority dateMar 21, 2007Also published asUS8121315Publication number11929242, 929242, US 2008/0232615 A1, US 2008/232615 A1, US 20080232615 A1, US 20080232615A1, US 2008232615 A1, US 2008232615A1, US-A1-20080232615, US-A1-2008232615, US2008/0232615A1, US2008/232615A1, US20080232615 A1, US20080232615A1, US2008232615 A1, US2008232615A1InventorsQinglin Song, Yongchun Tao, Shengli Pang, Tongqing LiuOriginal AssigneeGoer Tek Inc.Export CitationBiBTeX, EndNote, RefManReferenced by (10), Classifications (8), Legal Events (1) External Links: USPTO, USPTO Assignment, EspacenetCondenser microphone chip
US 20080232615 A1Abstract
Disclosed is a condenser microphone chip, comprising: a substrate (21); a diaphragm (26) spaced from the substrate; a curved beam (27) connected with the diaphragm (26) to anchor the diaphragm (26) to the substrate (21); a curved beam connecting part (29) having a shape of a substantially circular plate. The curved beam (27) is arranged in the diaphragm (26). The curved beam (27) includes a plurality of sub beams, each of the plurality of sub beams including a first sub beam portion extending in a substantially radial direction from a circumference of the curved beam connecting part (29); a second sub beam portion extending in a substantially circumferential direction from an end of the first sub beam portion away from the circumference of the curved beam connecting part (29) and having a shape of a substantial arc; and a third sub beam portion extending in the radial direction from an end of the second sub beam portion away from the first sub beam portion and connected to the diaphragm (26). The condenser microphone chip according to the present invention is high in sensitivity, low in noise, wide in frequency band, simple in manufacturing process, and high in reliability. In addition, the condenser microphone chip can be easily manufactured in mass production.
A condenser microphone chip is a capacitor composed of a diaphragm and a backplate. Currently, in most reports and patents a double-membrane capacitor structure which is manufactured by forming a diaphragm and a backplate on a silicon wafer by micromachining is adopted. Few efforts are made to the development of single-membrane silicon condenser microphone. A single-membrane silicon condenser microphone is reported in “Fabrication of Silicon Condenser Microphone Using Single Wafer Technology”, Journal of microelectromechanical systems, VOL. 1. No. 3, 1992, p 147-154. In the single-membrane silicon condenser microphone, a capacitor structure is formed by an edge portion of a diaphragm and a silicon substrate with the silicon substrate serving as a backplate and with a large hole at a center of the backplate serving as a sound hole. However, the single-membrane silicon condenser microphone is disadvantageous because an edge of the diaphragm is connected to a peripheral portion. When a sound wave is applied to the diaphragm, a maximum vibration occurs at a center portion of the diaphragm, and a small vibration is generated at the edge portion of the diaphragm. Because the center portion of the diaphragm is directly opposite to the sound hole of the backplate, mechanical sensitivity in the region with maximum amplitude is not used, so that the mechanical sensitivity of the diaphragm contributes less to sensitivity of the microphone.
In order that a diaphragm has good vibration performance, a residual stress in the diaphragm can be reduced. In the Publication titled Sensor and Actuators A. 31, 1992, 90-96, a material with tensile stress and a material with compressive stress are used to make a low-stress composite membranes for a microphone. In U.S. Pat. No. 6,622,368B1 in which silicon nitride/polysilicon/silicon nitride composite membrane structure is disclosed, the low-stress composite membrane is used as a diaphragm of a microphone. In the Publication “Sensor and Actuators A. 31,1992,149-152” and U.S. Pat. No. 6,012,335, a monocrystalline silicon diaphragm is made by doping monocrystalline silicon with boron. In the Publication “A High Sensitivity Polysilicon Diaphragm Condenser Microphone”, 1998 MEMS Conference, Heideberg Germany January 25-29, it is reported that a diaphragm is made with low-stress polysilicon. However, requirements for a growing process of a membrane is strict and it is difficult to assure uniformity of the membrane if vibration performance of the diaphragm is improved only by making a material of low residual stress.
It is an object of the present invention to provide a condenser microphone chip having a curved beam which can alleviate at least a part of the above problems.
The curved beam may extend in one of a substantial “S” shape, a shape of a substantial arc, and a substantial helical shape.
According to another aspect of the invention, the condenser microphone chip further comprises: an auxiliary beam including a first elongated portion configured by forming an opening in the diaphragm substantially parallel to an edge of the diaphragm at a predetermined distance from the edge, the first portion having two ends connected with the diaphragm; and a second elongated portion extending away from the diaphragm from a substantially middle portion of the first portion, the second portion being fixed to the substrate at an end of the second portion away from the first portion, and the first portion and the second portion being formed in a “T” shape together.
According to an aspect of the present invention, the condenser microphone chip further comprises: an auxiliary beam including a first elongated portion configured by forming an opening in the diaphragm substantially parallel to an edge of the diaphragm at a predetermined distance from the edge, the first portion having two ends connected with the diaphragm; and a second elongated portion extending away from the diaphragm from a substantially middle portion of the first portion, an end of the second portion away from the first portion being fixed to the substrate, and the first portion and the second portion being formed in a “T” shape together.
According to another aspect of the present invention, the condenser microphone chip further comprises: an auxiliary beam including a first elongated portion configured by forming an opening in the diaphragm substantially parallel to an edge of the diaphragm at a predetermined distance from the edge, the first portion having two ends connected with the diaphragm; and a second elongated portion extending away from the diaphragm from a substantially middle portion of the first portion, the second portion being fixed at an end of the second portion away from the first portion to the substrate, and the first portion and the second portion being formed in a “T” shape together.
The first embodiment according to the present invention will be described hereinafter with reference to FIGS. 1 through 6.
Referring to FIGS. 1 to 6, a condenser microphone chip according to a first embodiment of the present invention comprises: a substrate 21; a diaphragm 26 spaced from the substrate 21, for example, by a predetermined distance; and a curved beam 27 connected with the diaphragm 26 to anchor the diaphragm 26 to the substrate 21. The curved beam 27 may extend in one of a substantial “S” shape, a shape of a substantial arc, and a substantial helical shape. The curved beam 27 is illustrated as a beam extending in the “S” shape in FIG. 1. The condenser microphone chip may further comprise a dielectric layer 251 connected fixedly with or on a surface (an upper surface in FIG. 2) of the substrate 21, a conductive layer 60 (to be described in detail later) on a surface (an upper surface in FIG. 2) of the dielectric layer 25′; and a backplate side electrode 31 (to be described in detail later). The conductive layer 60 may be an n type semiconductor layer or a p type semiconductor layer formed by doping low-stress polysilicon with phosphor or boron. The dielectric layer 25′ may be formed of silicon oxide such as low temperature oxide (LTO), phosphosilicate glass (PSG), and tetraethyl orthosilicate (TEOS).
In another example of the present invention, the auxiliary beam 28 includes a first elongated portion configured by forming an opening in the diaphragm 26 substantially parallel to the edge of the diaphragm 26 at a predetermined distance from the edge, the first portion having two ends connected with the diaphragm 26; and a second elongated portion extending away from the diaphragm 26 from a substantially middle portion of the first portion, the second portion being fixed to the substrate 21_at an end of the second portion away from the first portion, for example, by the auxiliary beam support 25, and the first portion and the second portion being formed in a “T” shape together, as shown in FIG. 1.
In the illustrated examples, the edge of the diaphragm 26 is connected to the auxiliary beam connecting part 30 through the auxiliary beam 28, and the auxiliary beam connecting part 30 is fixed on a surface (an upper surface in FIGS. 2 and 6) of the auxiliary beam support 25. The auxiliary beam 28 accomplishes a function of supporting the diaphragm and serves as a lead wire for the electrode. The auxiliary beam 28 may be configured in many structures, and preferably may extend in the “T” shape, since the beam extending in the “T” shape can well release stress in the diaphragm in a certain space. Residual stress in the diaphragm can be sufficiently released since it is supported by the soft curved beam 27 and the auxiliary beam 28. The curved beam 27 serves as a spring, and thus can effectively prevent attachment of the diaphragm to the backplate and improve reliability of the condenser microphone chip.
In the examples shown in FIGS. 1-6, the diaphragm 26 is circular in shape, and the opening for forming the first portion of the auxiliary beam 28 is an are slit parallel to the edge of the diaphragm 26, so that the first portion is a beam portion extending in an arc shape, and the second portion is a straightline-shaped beam portion extending in the radial direction of the diaphragm 26 from the middle portion of the first portion. However, when the diaphragm has a polygonal shape, the opening may be parallel to a side of the polygonal diaphragm, and the first portion and the second portion may be formed in the “T” shape together. In the above examples, the opening is parallel to the edge of the diaphragm, but apparently the opening may be nonparallel to the edge of the diaphragm. For example, the opening may be positioned at any appropriate angle with respect to the edge of the diaphragm. In addition, the shape of the first portion and the second portion are not limited to the “T” shape, and they can be configured at any appropriate angle with respect to each other. In addition, in the above examples, the second portion extends from the middle portion of the first portion, but the present invention is not limited thereto. The second portion may extend from the other positions of the first portion, such as a portion between the middle portion and an end of the first portion.
The second embodiment according to the present invention will be described hereinafter with reference to FIGS. 7 through 20.
In another example of the present invention, the auxiliary beam 28 includes a first elongated portion configured by forming an opening in the diaphragm 26 substantially parallel to the edge of the diaphragm 26 at a predetermined distance from the edge, the first portion having two ends connected with the diaphragm 26; and a second elongated portion extending away from the diaphragm from a substantially middle portion of the first portion, the second portion being fixed at an end of the second portion away from the first portion to the substrate 21, for example, by the auxiliary beam support 25, and the first portion and the second portion being formed in a “T” shape together. The second elongated portion of the auxiliary beam may be attached to an auxiliary beam connecting part 30 connected with the auxiliary beam support 25.
In the illustrated examples, the curved beam 27 and the auxiliary beam 28 extend in a “T” shape. The beams extending in the “T” shape can well release stress in the diaphragm in a limited space. There is a gap of 2-4 μm between the diaphragm 26 and the backplate 23 a. A plurality of small holes 38 are disposed in a portion of the diaphragm 26 outside a range of a projection of an opening of the sound hole 33, which projection is on a surface of the diaphragm 26 and which opening is on a side of the diaphragm 26. The curved beam connecting part 29, the auxiliary beam connecting part 30, the curved beam 27, the auxiliary beam 28, and diaphragm 26 may be formed of conductive material, or may be made of be an n type semiconductor layer or a p type semiconductor layer formed by doping polysilicon with phosphor or boron.
The third embodiment according to the present invention will be described hereinafter with reference to FIGS. 21 through 28 and 7 through 20.
In an example of the present invention, the condenser microphone chip may further comprise a curved beam 27 connected with the diaphragm 26 to anchor the diaphragm 26 to the substrate 21. The curved beam 27 may extend in one of a substantial “S” shape, a shape of a substantial arc, and a substantial helical shape. Apparently, the curved beam 27 may extend in any other appropriate curved shapes. The curved beam 27 may be formed within the diaphragm 26.
In another example of the present invention, the auxiliary beam 28 includes a first elongated portion configured by forming an opening in the diaphragm 26 substantially parallel to the edge of the diaphragm 26 at a predetermined distance from the edge, the first portion having two ends connected with the diaphragm 26; and a second elongated portion extending away from the diaphragm 26 from a substantially middle portion of the first portion, the second portion being fixed at an end of the second portion away from the first portion to the substrate 21, for example, by the auxiliary beam support 25, and the first portion and the second portion being formed in a “T” shape together, as shown in FIG. 25. The second portion of the auxiliary beam 28 may be fixed at the end of the second portion away from the first portion to the auxiliary beam support 25 by an auxiliary beam connecting part 30.
In the illustrated examples, the diaphragm 26 and the backplate 23 a may be substantially identical in shape with each other and be aligned with each other in a direction perpendicular to a surface of the diaphragm. The diaphragm 26 is located within the auxiliary beam connecting part 30, and may be connected at a center portion of the diaphragm without a hole to an upper end of the supporting member 24′. The edge of the diaphragm 26 is connected to the auxiliary beam connecting part 30 through the auxiliary beam 28, and the auxiliary beam 28 may be configured in many structures. In the illustrated examples, the auxiliary beam 28 extends in a “T” shape. The beams extending in the “T” shape can accomplish a good stress releasing effect in a limited space. There is a gap of 2-4 μm between the diaphragm 26 and the backplate 23 a. A plurality of small holes 38 are disposed in a portion of the diaphragm 26 outside a range of a projection of the opening of the sound hole 33, which projection is on a surface of the diaphragm 26 and which opening is on a side of the diaphragm 26. The auxiliary beam connecting part 30, the auxiliary beam 28, and diaphragm 26 may be formed of conductive material, or may be made of be an n type semiconductor layer or a p type semiconductor layer formed by doping polysilicon with phosphor or boron. The diaphragm side electrode 32 is disposed on a side on the auxiliary beam connecting part 30.
In addition, the use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context.
Referenced byCiting PatentFiling datePublication dateApplicantTitleUS8249281 *Jan 1, 2010Aug 21, 2012Aac Acoustic Technologies (Shenzhen) Co., Ltd.Condenser microphoneUS8542851 *May 11, 2011Sep 24, 2013Omron CorporationAcoustic sensor and microphoneUS8698255 *Apr 6, 2010Apr 15, 2014Robert Bosch GmbhSemiconductor component having a micromechanical microphone structureUS8942394Dec 22, 2009Jan 27, 2015Stmicroelectronics S.R.L.Integrated acoustic transducer obtained using MEMS technology, and corresponding manufacturing processUS20100290648 *Jan 1, 2010Nov 18, 2010Aac Acoustic Technologies (Shenzhen) Co., LtdCondenser MicrophoneUS20110278683 *May 10, 2011Nov 17, 2011Omron CorporationAcoustic sensor and method of manufacturing the sameUS20110280419 *May 11, 2011Nov 17, 2011Omron CorporationAcoustic sensor and microphoneUS20120091545 *Apr 6, 2010Apr 19, 2012Frank ReichenbachSemiconductor component having a micromechanical microphone structureUS20130177180 *Jan 11, 2012Jul 11, 2013Analog Devices, Inc.MEMS Microphone with Springs and Interior SupportWO2013164021A1 *May 2, 2012Nov 7, 2013Epcos AgMems microphone assembly and method of manufacturing the mems microphone assembly* Cited by examinerClassifications U.S. Classification381/174International ClassificationH04R19/04Cooperative ClassificationH04R31/00, H04R19/04, H04R19/005European ClassificationH04R19/04, H04R19/00S, H04R31/00Legal EventsDateCodeEventDescriptionFeb 5, 2008ASAssignmentOwner name: GOER TEK INC., SWITZERLANDFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SONG, QINGLING;TAO, YONGCHUN;PANG, SHENGII;AND OTHERS;REEL/FRAME:020475/0940Effective date: 20071122RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services