WO2019078532A1 - Mems microphone - Google Patents

Abstract

The present invention relates to a MEMS microphone for preventing damage caused by sound pressure. The MEMS microphone has a sound inlet part, which is connected between a substrate having a partially opened opening and a MEMS transducer provided at the upper part of the opening. The sound inlet part includes a plurality of sound inlet ports to which a sound signal is applied from the outside. The MEMS transducer includes a diaphragm at the upper part thereof. The diaphragm has a plurality of vent holes formed at the edge thereof. The vent hole has a structure in which an open region is increased by air pressure of the sound signal. According to the present invention, the sound inlet part is provided between the opening of the substrate and the MEMS transducer, and the plurality of vent holes are formed such that the open region is varied at the edge of the diaphragm of the MEMS transducer, thereby enabling the diaphragm to be prevented from being damaged by air pressure of the sound signal, and waterproofness and broadband frequency characteristics to improve.

Description

MEMS microphone

The present invention relates to a MEMS microphone, and more particularly, to an MEMS microphone having an acoustic inlet formed with a plurality of acoustic inlets between a partially open printed circuit board and a MEMS transducer sensing acoustic signals, The present invention relates to a MEMS microphone for preventing vibration of a diaphragm due to an air pressure of an acoustic signal and improving water resistance and broadband frequency characteristics by forming a plurality of vent holes varying in area of the MEMS microphone.

A microphone is a device that converts an acoustic signal into an electric signal, and is used in an acoustic device, a communication device, a medical device, or the like. As the various devices with built-in microphones become smaller in size, miniaturization of microphones is required. In response to these demands, the development of MEMS microphones is being actively pursued.

The MEMS microphones are becoming very compact, and they are able to carry out the separate production process of the parts in a batch, and have been greatly attracted to the performance and the production efficiency.

Recently, semiconductor processing technology using micromachining has been used as a technique for integrating a micro device. This technique, called MEMS, can be used to manufacture micro-sensors, actuators, and electromechanical structures in micrometers (micrometers) using semiconductor processing, especially micromachining techniques employing integrated circuit technology. MEMS microphones manufactured using such a micromachining technology can be miniaturized, high-performance, multifunctional, and integrated through ultrafine micromachining. In addition, there is an advantage that stability and reliability can be improved.

MEMS microphones are mainly divided into a piezo type and a condenser type. Because of the excellent frequency response characteristics of acoustic bands including voice, condenser type is mainly used for MEMS microphones.

However, in a conventional MEMS microphone, when a sound signal is applied at a high pressure, a diaphragm of a MEMS transducer that electrically converts an acoustic signal is often damaged.

[Prior Art Literature]

[Patent Literature]

(Patent Document 1) Korean Patent Publication No. 10-1452402 (Publication Date: Oct. 22, 2014)

(Patent Document 2) Korean Patent Laid-Open Publication No. 10-2015-0018695 (Publication date 2015.02.24)

(Patent Document 3) Korean Patent Registration No. 10-1333573 (Publication date 2013.11.27)

(Patent Document 4) Korean Registered Patent Application No. 10-1758017 (Publication date: Jul. 13, 2017)

The MEMS microphone according to the present invention has the following problems.

First, a MEMS microphone for preventing the damage of the MEMS transducer due to the air pressure of the acoustic signal is provided.

Second, there is provided a MEMS microphone having an acoustic inlet between a substrate and a MEMS transducer for improving waterproof and broadband frequency characteristics.

Third, a plurality of vent holes are formed in the MEMS transducer to vary the area of the open area at the edge of the diaphragm, thereby preventing breakage of the diaphragm due to the air pressure of the acoustic signal, improving the SNR characteristic and the broadband frequency characteristic To provide a MEMS microphone.

The solution of the present invention is not limited to those mentioned above, and other solutions not mentioned can be clearly understood by those skilled in the art from the following description.

In order to achieve the above objects, a MEMS microphone according to the present invention includes an acoustic wave introducing unit for applying an acoustic signal between a substrate and a MEMS transducer, and the area of the open area of the MEMS transducer And a plurality of vent holes for increasing the number of vent holes. The MEMS microphone of the present invention improves the waterproof and broadband frequency characteristics and can prevent the damage of the MEMS transducer due to the air pressure of the acoustic signal.

According to another aspect of the present invention, there is provided a MEMS microphone including: a substrate through which an acoustic signal flows from an outside through an opening portion; A MEMS transducer disposed at an upper portion of the opening of the substrate and including a diaphragm having a plurality of vent holes at an upper portion thereof for receiving an acoustic signal flowing into the opening and converting the acoustic signal into an electrical signal; An acoustic transducer disposed between the substrate and the MEMS transducer and having a plurality of acoustic inlets for providing the introduced acoustic signals to the MEMS transducer; And a cover coupled to the substrate to seal the inner space on which the MEMS transducer and the acoustic inlet are installed.

In one embodiment of this feature, the acoustic inlet comprises: A plurality of sound inlets are provided at the center portion and the edge, respectively, and the acoustic inlets formed at the edges of the sound inlets formed at the center portion have a larger diameter.

In another embodiment, the diaphragm includes: Wherein the vent hole is opened in a slot shape of a semicircle having a predetermined width and a portion between both ends of the vent hole is bent by the air pressure of the acoustic signal when the acoustic signal is discharged, Respectively.

In another embodiment, the diaphragm includes: And a portion between both ends of the vent hole is formed into a bent shape bent at a predetermined angle.

In another embodiment, the diaphragm includes: And bent grooves are formed on one surface of the portion between both ends of the vent hole.

In another embodiment, the diaphragm includes: Both sides of the portion between both ends of the vent hole are formed to be stepped so as to have different thicknesses.

In another embodiment, the diaphragm includes: Both sides of the portion between both ends of the vent hole are formed in a concavo-convex shape.

In another embodiment, the vent hole includes first and second vent holes having a pair of different shapes; Wherein the first vent hole is open in a slot shape of a semicircle having a predetermined width, the second vent hole is provided inside the center of the first vent hole and opened in a circular shape having a predetermined diameter; The diaphragm is formed such that at the time of discharging the acoustic signal, both ends of the first vent hole and a portion between the second vent hole are bent by the air pressure of the acoustic signal, and the area of the open area of the first vent hole is variable Respectively.

In another embodiment, the diaphragm includes: A stepped shape having a different thickness, a stepped shape having a different thickness and a bent shape in which each of a portion between the one end of the first vent hole and a portion between the second vent holes, a portion between the other end of the first vent hole and a portion between the second vent holes, And is formed in any one of concave and convex shapes on both sides.

The MEMS microphone according to the present invention has the following effects.

First, according to the present invention, waterproof and broadband frequency characteristics can be improved by disposing an acoustic inlet unit for applying an acoustic signal between a substrate on which the opening is formed and a MEMS transducer provided on the opening.

Second, the present invention provides a plurality of vent holes that increase the area of the open area at the edge of the diaphragm of the MEMS transducer, thereby preventing breakage of the vacuum plate due to the air pressure of the acoustic signal.

Thirdly, since the area of the open area of the vent hole of the diaphragm is varied, when the area of the open area is small, the signal-to-noise ratio (SNR) characteristic and the wide band frequency characteristic can be improved.

The effects of the present invention are not limited to those mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description.

FIG. 1 is a view showing the construction of a bottom type MEMS microphone according to the present invention,

FIGS. 2A and 2B are plan views showing a configuration according to the embodiment of the sound inlet shown in FIG. 1,

FIG. 3 is a plan view showing a diaphragm of the MEMS transducer shown in FIG. 1,

Fig. 4 is a view showing a part of the configuration of the diaphragm shown in Fig. 3,

FIGS. 5A to 5D are cross-sectional views taken along the line A-A 'showing a partial configuration according to the embodiment of the diaphragm shown in FIG. 4, and FIGS.

6 is a view showing a partial configuration according to another embodiment of the diaphragm shown in Fig.

100: MEMS microphone

110: substrate

120: cover

130: MEMS transducer

140: diaphragm

142: open area variable regulator

150: semiconductor integrated circuit

160: Bonding wire

170: Acoustic inlet

180: Sound inlet

190: Vent hole

In the MEMS microphone according to the present invention,

A substrate through which an acoustic signal is introduced from the outside through an opening partly opened; A MEMS transducer disposed at an upper portion of the opening of the substrate and including a diaphragm having a plurality of vent holes at an upper portion thereof for receiving an acoustic signal flowing into the opening and converting the acoustic signal into an electrical signal; An acoustic transducer disposed between the substrate and the MEMS transducer and having a plurality of acoustic inlets for providing the introduced acoustic signals to the MEMS transducer; And a cover coupled to the substrate to seal the inner space on which the MEMS transducer and the acoustic inlet are installed,

Wherein the diaphragm is opened in a slot shape of a semicircle having a predetermined width and the portion between both ends of the vent hole is bent by the air pressure of the acoustic signal when the acoustic signal is discharged, And the area is variable,

And the diaphragm is formed with a bending groove on one side of the portion between both ends of the vent hole.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Wherever possible, the same or similar parts are denoted using the same reference numerals in the drawings.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms as used herein include plural forms as long as the phrases do not expressly express the opposite meaning thereto.

Means that a particular feature, region, integer, step, operation, element and / or component is specified and that other specific features, regions, integers, steps, operations, elements, components, and / It does not exclude the existence or addition of a group.

All terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Predefined terms are further interpreted as having a meaning consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or very formal meanings unless defined otherwise.

The MEMS microphone according to the present invention may be described as a bottom type, for example. The present invention has an acoustic wave inlet formed between a substrate and a MEMS transducer and having a plurality of acoustic inlets. In the MEMS microphone of the present invention, a plurality of vent holes are formed in the diaphragm of the MEMS transducer. The vent holes are arranged at equal intervals on the edge of the diaphragm, and a part of them is opened in a semicircular shape without being cut in the diaphragm. In the vent hole, when a high-pressure acoustic signal is input, the unbraided portion of the diaphragm is bent by the air pressure of the acoustic signal, thereby increasing the area of the open area.

The MEMS microphone according to the present invention improves the waterproof and broadband frequency characteristics by means of the sound inlet, and the area of the open area of the vent hole of the diaphragm is variable, thereby preventing damage of the diaphragm due to the air pressure of the acoustic signal by the vent hole And broadband frequency characteristics such as signal-to-noise ratio (SNR) characteristic improvement, frequency increase and roll off can be improved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing the configuration of a bottom type MEMS microphone according to the present invention.

Referring to FIG. 1, the MEMS microphone 100 of the present invention has a bottom type structure. That is, the MEMS microphone 100 of the present invention receives a sound signal from a lower portion of the substrate 110 and senses an acoustic signal.

To this end, the MEMS microphone 100 of the present invention has a structure in which an acoustic inlet 170 is coupled between a substrate 110 having an opening 112 partially opened and a MEMS transducer 130 having a diaphragm 140 formed thereon And a plurality of vent holes (190 in FIG. 3) are provided in the diaphragm 140 of the MEMS transducer 130. The sound inlet 170 is provided with a plurality of sound inlets 180 which penetrate up and down to receive an acoustic signal flowing through the opening 112 of the substrate 110 and transmit the received sound signal to the MEMS transducer 130. The vent hole 190 has a structure in which the area of the open area is increased according to the air pressure of the acoustic signal due to the elasticity of the diaphragm 140.

The MEMS microphone 100 according to the present invention prevents the diaphragm 140 from being damaged when the air pressure of the acoustic signal is high due to the acoustic inlet 170 and the vent hole 190 and the waterproof property and the signal- (SNR) characteristics and broadband frequency characteristics such as frequency increase and attenuation.

The MEMS microphone 100 includes a substrate 110, a cover 120, a MEMS transducer 130, a diaphragm 140, a semiconductor integrated circuit (ASIC) 150, a plurality of Bonding wires 160 and an acoustic inlet 170.

The substrate 110 is, for example, a printed circuit board (PCB), and an opening 112 is formed through which a part of the substrate 110 is partially opened. The opening 112 receives the acoustic signal flowing from the outside, that is, the lower portion, and provides the acoustic signal to the acoustic inlet 170. The sound inlet 170 is coupled to the upper surface of the opening 112.

The cover 120 is made of, for example, a metal can and is joined to the edge of the upper surface of the substrate 110 to form an inner space 102. A MEMS transducer 130, a semiconductor integrated circuit 150, a bonding wire 160, and an acoustic inlet 170 are installed in the inner space 102.

The acoustic inlet 170 is disposed above the opening 112 of the substrate 110 and is coupled between the substrate 110 and the MEMS transducer 130. The acoustic inlet 170 is, for example, a silicon wafer, and a plurality of acoustic inlets 180 are formed through the upper and lower portions. The acoustic inlets 180 are disposed at the center of the acoustic inlet 170 or at the center and the edge of the acoustic inlet 170.

The MEMS transducer 130 is formed on, for example, a silicon wafer, and is disposed on the upper portion of the acoustic inlet 170, and a diaphragm 140 is provided on the upper portion. The MEMS transducer 130 senses the vibrating plate 140 when the vibrating plate 140 is vibrated by the incoming acoustic signal.

The MEMS transducer 130 receives the acoustic signal provided from the acoustic inlet 170 and converts the acoustic signal into an electrical signal corresponding to the vibration of the diaphragm 140. The MEMS transducer 130 is electrically connected to the semiconductor integrated circuit 150 through a plurality of bonding wires 160. In this embodiment, the acoustic inlet 170 is provided as a silicon wafer and bonded to the MEMS transducer 130 in a wafer-to-wafer bonding manner.

The diaphragm 140 has a plurality of vent holes 190 formed at the edges thereof. The diaphragm 140 vibrates in response to an acoustic signal applied through the acoustic inlet 170. The vent hole 190 has a structure in which a part of the diaphragm 140 is bent by the air pressure of the acoustic signal to increase the area of the open area. The diaphragm 140 will be described in detail with reference to FIGS. 3 to 6. FIG.

The semiconductor integrated circuit 160 is provided as an application specific integrated circuit (ASIC), for example, and is installed on the substrate 110 to receive an electrical signal from the MEMS transducer 130, amplify the electrical signal, Or a digital signal.

FIGs. 2A and 2B are plan views showing a configuration according to the embodiment of the sound inlet shown in FIG. 1. FIG.

Referring to FIGS. 2A and 2B, the sound inlet 170a of the embodiment has a plurality of sound inlets 180a uniformly disposed at the center thereof. At this time, the sound input ports 180a have the same diameter.

The sound inlet portion 170b of another embodiment is provided with a plurality of sound inlet ports 180b and 180c at the center and the edge thereof. At this time, the acoustic inlets 180b and 180c have different diameters at the center and the edge. In this embodiment, the acoustic inlet 180c formed at the edge of the acoustic inlet 180b formed at the center portion has a larger diameter.

3 is a plan view of a diaphragm showing the configuration of the vent hole shown in Fig. 3, and Figs. 5A to 5D are cross-sectional views of the diaphragm shown in Fig. 4, Sectional views illustrating a configuration according to an embodiment of the present invention.

3 to 5D, the diaphragm 140 of the present invention is provided with a plurality of vent holes 190 at the edges thereof. The vent hole 190 is equally disposed at the edge of the diaphragm 140. The vent hole 190 has a structure in which a part of the diaphragm 140 is bent by the air pressure of the acoustic signal to increase the area of the open area.

Specifically, the vent hole 190 is opened in a slot shape of a semicircle having a constant width d so that one side adjacent to the center C of the diaphragm 140, that is, . The open region variable regulating portion 142 is provided in the portion B not cut from the diaphragm 140. The open area variable regulating portion 142 is located between both ends of the vent hole 190, as shown in FIG. When the acoustic signal is discharged to the diaphragm 140, the open area variable regulating portion 142 is bent by the air pressure of the acoustic signal to increase the area of the open area of the vent hole 190.

When the area of the open area is small, the vent hole 190 can improve the signal-to-noise ratio (SNR) performance of the MEMS microphone 100 and improve the wide-band frequency characteristic. However, when the area of the open area is small, when the air pressure of the acoustic signal is high, the diaphragm 140 is damaged. Accordingly, the vent hole 190 of the present invention is provided in a state where the area of the open area is reduced, and when the acoustic signal is applied, the area of the open area is increased by the open area variable regulator 142.

Therefore, when the air pressure of the acoustic signal is high, the MEMS microphone 100 of the present invention is deflected by the open region variable regulator 142 to increase the area of the open region, The diaphragm 140 is not damaged. The open area variable regulator 142 of the present invention may be provided in various shapes.

5A, the diaphragm 140a of the first embodiment is formed in a bent shape bent at a predetermined angle from the diaphragm 140a to the unblemished portion B1 to form an open region variable regulating portion 142a .

As shown in FIG. 5B, the diaphragm 140b of the second embodiment includes a bending groove formed on one surface of the unbraided portion B2 from the diaphragm 140b to constitute an open area variable regulating portion 142b.

The diaphragm 140c of the third embodiment is formed so that both sides of the unbraided portion B3 from the diaphragm 140c are stepped so as to have different thicknesses so that the open region variable regulating portion 142c . The open-area variable adjustment portion 142c of this embodiment is formed such that the side of the vent hole 190c is thinner than the center of the diaphragm 140c.

5D, a diaphragm 140d of the fourth embodiment is formed in a concavo-convex shape on a part of both sides of the uncut portion B4 of the diaphragm 140d to constitute an open region variable regulating portion 142d .

Each of the open region variable regulating portions 142a to 142d is bent by the air pressure of the acoustic signal to increase the area of the open area of each of the vent holes 190a to 190d.

6 is a view showing a partial configuration according to another embodiment of the diaphragm shown in Fig.

Referring to FIG. 6, the diaphragm 140 'of this embodiment has a pair of vent holes 190' of different shapes. That is, the vent hole 190 'includes first and second vent holes 192 and 194. The first vent hole 192 generally has the same or similar shape as the vent hole 190 of FIG. For example, the first vent hole 192 is opened in the form of a half-circle having a constant width. The second vent hole 194 is provided inside the center of the first vent hole 192 and is opened in a circular shape having a predetermined diameter.

4, portions of the diaphragm 140 'between both ends of the first vent hole 192 and the second vent hole 194 (B': B5 and B6) And is formed so as to be bent by air pressure so that the area of the open area of the first vent hole 192 is variable. The diaphragm 140 'may include a portion B5 between one end of the first vent hole 192 and one side of the second vent hole 194, the other end of the first vent hole 192 and the second vent hole 194, Side portion B6 of the diaphragm 140 'is formed so as not to be cut away from the diaphragm 140', one side adjacent to the center of the diaphragm 140 '. The open region variable regulating portion 142 'is provided in the portion B' that is not cut out from the diaphragm 140 '.

The open region variable regulating portion 142 'is disposed between one end of the first vent hole 192 and one side of the second vent hole 194 and between the other end of the first vent hole 192 and the second vent hole 194 Respectively. When the acoustic signal is discharged to the diaphragm 140 ', the open area variable regulating portion 142' is bent by the air pressure of the acoustic signal to increase the area of the open area of the first vent hole 192.

As shown in FIGS. 5A to 5D, the open-area variable adjustment portion 142 'may be formed in a bent shape, a bent groove shape, a stepped shape having different thicknesses, And is bent at a certain angle by the air pressure to increase the area of the open area of the first vent hole 192.

Therefore, when the air pressure of the acoustic signal is high, the diaphragm 140 'of this embodiment is also deflected by the open-area variable regulator 142' to increase the area of the open area, It is possible to prevent the diaphragm 140 'from being damaged.

Embodiments described in the specification The accompanying drawings are merely illustrative of some of the technical ideas included in the present invention. Accordingly, the embodiments disclosed herein are for the purpose of describing rather than limiting the technical spirit of the present invention, and it is apparent that the scope of the technical idea of the present invention is not limited by these embodiments. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (6)

In a MEMS microphone, A substrate through which an acoustic signal is introduced from the outside through an opening partly opened; A MEMS transducer disposed at an upper portion of the opening of the substrate and including a diaphragm having a plurality of vent holes at an upper portion thereof for receiving an acoustic signal flowing into the opening and converting the acoustic signal into an electrical signal; An acoustic transducer disposed between the substrate and the MEMS transducer and having a plurality of acoustic inlets for providing the introduced acoustic signals to the MEMS transducer; And a cover coupled to the substrate to seal the inner space on which the MEMS transducer and the acoustic inlet are installed, Wherein the diaphragm is opened in a slot shape of a semicircle having a predetermined width and the portion between both ends of the vent hole is bent by the air pressure of the acoustic signal when the acoustic signal is discharged, And the area is variable, Wherein the diaphragm is formed with a bending groove on one side of a portion between both ends of the vent hole. In a MEMS microphone, A substrate through which an acoustic signal is introduced from the outside through an opening partly opened; A MEMS transducer disposed at an upper portion of the opening of the substrate and including a diaphragm having a plurality of vent holes at an upper portion thereof for receiving an acoustic signal flowing into the opening and converting the acoustic signal into an electrical signal; An acoustic transducer disposed between the substrate and the MEMS transducer and having a plurality of acoustic inlets for providing the introduced acoustic signals to the MEMS transducer; And a cover coupled to the substrate to seal the inner space on which the MEMS transducer and the acoustic inlet are installed, Wherein the diaphragm is opened in a slot shape of a semicircle having a predetermined width and the portion between both ends of the vent hole is bent by the air pressure of the acoustic signal when the acoustic signal is discharged, And the area is variable, Wherein the diaphragm is stepped so that both sides of the vent hole have different thicknesses. In a MEMS microphone, A substrate through which an acoustic signal is introduced from the outside through an opening partly opened; A MEMS transducer disposed at an upper portion of the opening of the substrate and including a diaphragm having a plurality of vent holes at an upper portion thereof for receiving an acoustic signal flowing into the opening and converting the acoustic signal into an electrical signal; An acoustic transducer disposed between the substrate and the MEMS transducer and having a plurality of acoustic inlets for providing the introduced acoustic signals to the MEMS transducer; And a cover coupled to the substrate to seal the inner space on which the MEMS transducer and the acoustic inlet are installed, Wherein the diaphragm is opened in a slot shape of a semicircle having a predetermined width and the portion between both ends of the vent hole is bent by the air pressure of the acoustic signal when the acoustic signal is discharged, And the area is variable, Wherein the diaphragm has a concavo-convex shape on both sides of a portion between both ends of the vent hole. The method according to any one of claims 1 to 3, The sound inlet portion comprising: Wherein a plurality of acoustic inlets are provided at the center portion and the edge, respectively, and the acoustic inlets formed at the edges of the acoustic inlets formed at the center portion have a larger diameter. In a MEMS microphone, A substrate through which an acoustic signal is introduced from the outside through an opening partly opened; A MEMS transducer disposed at an upper portion of the opening of the substrate and including a diaphragm having a plurality of vent holes at an upper portion thereof for receiving an acoustic signal flowing into the opening and converting the acoustic signal into an electrical signal; An acoustic transducer disposed between the substrate and the MEMS transducer and having a plurality of acoustic inlets for providing the introduced acoustic signals to the MEMS transducer; And a cover coupled to the substrate to seal the inner space on which the MEMS transducer and the acoustic inlet are installed, Wherein the vent hole includes first and second vent holes having a pair of different shapes; Wherein the first vent hole is open in a slot shape of a semicircle having a predetermined width, the second vent hole is provided inside the center of the first vent hole and opened in a circular shape having a predetermined diameter; The diaphragm is formed such that at the time of discharging the acoustic signal, both ends of the first vent hole and a portion between the second vent hole are bent by the air pressure of the acoustic signal, so that the area of the open area of the first vent hole is variable And a second microphone connected to the second microphone. The method of claim 5, The diaphragm includes: A stepped shape having a different thickness, a stepped shape having a different thickness and a bent shape in which each of a portion between the one end of the first vent hole and a portion between the second vent holes, a portion between the other end of the first vent hole and a portion between the second vent holes, And a concavo-convex shape on both sides.

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