CN101677423A

CN101677423A - Micro electromechanical system (MEMS) microphone

Info

Publication number: CN101677423A
Application number: CN200810216251A
Authority: CN
Inventors: 吴志江; 刘明; 王凯
Original assignee: AAC Acoustic Technologies Changzhou Co Ltd
Current assignee: AAC Technologies Holdings Changzhou Co Ltd
Priority date: 2008-09-19
Filing date: 2008-09-19
Publication date: 2010-03-24

Abstract

The invention relates to a microphone, in particular to a micro electromechanical system (MEMS) microphone which has more stable performance and is used on electronic equipment. A sound channel is arranged in a substrate and is communicated with the outer space of a sound inlet hole and a concave part of an MEMS chip to form a complete sound inlet space; the substrate is provided with a shieldingcover which can shield the electromagnetic interference and other interferences; and the shielding cover and the substrate form a back sound cavity. The space of the back sound cavity is enlarged obviously and is not restricted by the substrate, thus the frequency response characteristic and the open-circuit sensitivity of the encapsulated MEMS microphone are kept minimum. The shielding cover shields other external interferences, thus the MEMS microphone has more stable performance.

Description

The MEMS microphone

[technical field]

The present invention relates to a kind of microphone, specifically refer to a kind of being applied on the electronic equipment, have the MEMS of stability (Micro-Electro-Mechanical-System Microphone) microphone more.

[background technology]

Development along with wireless telecommunications, Global Mobile Phone Users is more and more, the user not only is satisfied with conversation to the requirement of mobile phone, and want high-quality communication effect can be provided, especially at present the development of mobile multimedia technology, the speech quality of mobile phone becomes more important, and the microphone of mobile phone is as the voice pick device of mobile phone, and its design quality directly influences speech quality.

Use at present more and microphone better performances is MEMS (Micro-Electro-Mechanical-System Microphone) microphone, shown in accompanying drawing 1,2; It comprises the band sound hole 110 ' upper cover plate 100 ', a shell wall 200 ', around and support upper cover plate 100 '; One substrate 300 ', be equipped with on it MEMS chip 400 of mutual electrical connection ', the application-specific integrated circuit ASIC chip 500 of interior integrated preamplifier ' and other passive components, described substrate 300 ' support shell wall 200 ' and upper cover plate 100 '; MEMS chip 400 ' a be provided with depressed part 610 ', MEMS chip 400 ' be attached to substrate 300 ' on, thereby MEMS chip 400 ' on depressed part 610 ' and substrate 300 ' between form the back operatic tunes 600 of microphone '.Above-mentioned structure that provides a kind of silica-based microphone, as can be seen MEMS chip 400 ' and substrate 300 ' between form the back operatic tunes 600 of microphone ' insufficient space enough big, the frequency response performance that this will certainly minimal change MEMS chip upper sensor self; And sound can be directly incident on the silicon base vibrative membrane sheet, also can be subjected to ambient light, electromagnetic interference simultaneously, and this will influence the performance and the life-span of microphone.

[summary of the invention]

The objective of the invention is to solve the microelectromechanical-systems microphone and when receiving the external voice signal, can not shield other electromagnetic signals, and because self operatic tunes space, back is big inadequately, make the frequency response performance of transducer before and after encapsulation, change big, influence the problem of microphone overall performance, and a kind of MEMS microphone with big back operatic tunes is provided.

In order to achieve the above object, technical scheme of the present invention is as follows:

A kind of MEMS microphone comprises: the upper cover plate, a shell wall of a band sound hole, around and support upper cover plate; One substrate is equipped with the MEMS chip and the application-specific integrated circuit ASIC chip of mutual electrical connection, described base plate supports shell wall and upper cover plate on it; The inside of described substrate is provided with sound channel, this sound channel connects with the sound hole of upper cover plate and the depressed part of MEMS chip respectively, also be provided with the radome that MEMS chip and application-specific integrated circuit ASIC chip are covered on the substrate, the space that radome and substrate constitute is the back operatic tunes.

Improvement of the technical scheme is: described substrate comprise the upper substrate that is connected with shell wall, around and support the sidewall of upper substrate and the infrabasal plate that is connected with sidewall.

Improvement of the technical scheme is: have first through hole that at least one and sound hole connect on the described upper substrate.

Improvement of the technical scheme is: first through hole on the described upper substrate is located in the unlapped area surface of radome.

Improvement of the technical scheme is: described MEMS chip depressed part relative position on substrate has second through hole that connects with substrate internal sound passage.

Described radome comprises that metal material, plastic material or ceramic material make.

MEMS microphone of the present invention, be provided with sound channel in substrate inside, this sound channel connects with the space outerpace of sound hole and the depressed part of MEMS chip respectively, constitute one and complete enter space, on substrate, be provided with the radome of preventing other interference such as electromagnetism, radome and substrate form the back operatic tunes, this operatic tunes space obviously increases, thereby make Frequency Response and open circuit sensitivity minimum after the mems microphone encapsulation, radome has shielded other external interference, and the performance of microphone is more stable like this.

[description of drawings]

The microphone perspective view of Fig. 1 for disclosing in the background technology of the present invention;

Fig. 2 is the cross-sectional view of the microphone that discloses in the background technology of the present invention;

Fig. 3 is the perspective view of a preferred embodiment of the present invention;

Fig. 4 is the cross-sectional view of a preferred embodiment of the present invention.

[embodiment]

Below in conjunction with accompanying drawing, MEMS microphone of the present invention is elaborated.

See shown in Fig. 3,4, be a preferred embodiment of MEMS microphone of the present invention, it comprise a band sound hole 110 upper cover plate 100, a shell wall 200, around and support upper cover plate 100; One substrate 300, described substrate 300 supports shell wall 200 and upper cover plate 100, and substrate 300 is combined into a cube cavity with shell wall 200, upper cover plate 100; At cavity inside, the MEMS chip 400 and the application-specific integrated circuit ASIC chip 500 of mutual electrical connection is installed on the substrate 300.

Described substrate 300 comprises three-decker, promptly the upper substrate 310 that is connected with shell wall 200, around and support the sidewall 320 of upper substrate 310 and the infrabasal plate 330 that is connected with sidewall 320.Because sidewall 320 is around between support upper substrate 310 and the infrabasal plate 330, thereby the groove that the inside of substrate 300 forms is a sound channel 340, as shown in Figure 4; Certainly, substrate 300 also might comprise the structure more than four layers or four layers according to actual needs, in this not explanation successively.

Also be provided with the radome 700 that MEMS chip 400 and application-specific integrated circuit ASIC chip 500 are covered on the substrate 300, radome 700 available metal materials, plastic material or ceramic material are made.Radome 700 in the present embodiment is a metal cap, radome 700 constitutes a confined space with upper substrate 310, this confined space is exactly the back operatic tunes 600, clearly, the space of this back operatic tunes 600 obviously greater than the back operatic tunes 600 of Fig. 1,2 described microphones ' the space.Thereby make Frequency Response and open circuit sensitivity minimum after the mems microphone encapsulation, improved the acoustical behavior of MEMS chip 400, moreover radome 700 shielded other external interference, as light, electromagnetic interference, the performance of microphone is more stable like this.

See Fig. 4, have first through hole 312 that connects with sound hole 110 on the upper substrate 310, can open a plurality of holes as required certainly, the position of this first through hole 312 is located on the unlapped upper substrate area surface of radome; MEMS chip 400 depressed parts 610 have second through hole 311 that connects with substrate 300 internal sound passages 340 relatively in the position of upper substrate 310, like this, this sound channel 340 connects with the depressed part 610 of the sound hole 110 of upper cover plate 100 and MEMS chip 400 respectively, constitutes one and complete enters space.No matter what layer structure substrate 300 adopts, its MEMS chip 400 depressed parts 610 connect with the sound hole 110 of upper cover plate 100, like this, substrate 300 with its on the space that constitutes of the radome that is connected 700 be the back operatic tunes 600 of sealing, then this back operatic tunes 600 is not subjected to the restriction of substrate 300, the back operatic tunes 600 that increases makes Frequency Response and the open circuit sensitivity minimum after the mems microphone encapsulation, has improved the performance of microphone integral body.

The above only is a better embodiment of the present invention; protection scope of the present invention is not exceeded with above-mentioned execution mode; as long as the equivalence that those of ordinary skills do according to disclosed content is modified or changed, all should include in the protection range of putting down in writing in claims.

Claims

1, a kind of MEMS microphone comprises: the upper cover plate, a shell wall of a band sound hole, around and support upper cover plate; One substrate is equipped with the MEMS chip and the application-specific integrated circuit ASIC chip of mutual electrical connection, described base plate supports shell wall and upper cover plate on it; It is characterized in that: the inside of described substrate is provided with sound channel, this sound channel connects with the sound hole of upper cover plate and the depressed part of MEMS chip respectively, also be provided with the radome that MEMS chip and application-specific integrated circuit ASIC chip are covered on the substrate, the space that radome and substrate constitute is the back operatic tunes.

2, MEMS microphone according to claim 1 is characterized in that: described substrate comprise the upper substrate that is connected with shell wall, around and support the sidewall of upper substrate and the infrabasal plate that is connected with sidewall.

3, MEMS microphone according to claim 2 is characterized in that: have first through hole that at least one and sound hole connect on the described upper substrate.

4, MEMS microphone according to claim 3 is characterized in that: first through hole on the described upper substrate is located in the unlapped area surface of radome.

5, MEMS microphone according to claim 1 is characterized in that: described MEMS chip depressed part relative position on substrate has second through hole that connects with substrate internal sound passage.

6, MEMS microphone according to claim 1 is characterized in that: described radome comprises that metal material, plastic material or ceramic material make.