CN201403194Y

CN201403194Y - Mems microphone

Info

Publication number: CN201403194Y
Application number: CN2009201359478U
Authority: CN
Inventors: 苏永泽
Original assignee: AAC Acoustic Technologies Shenzhen Co Ltd; AAC Acoustic Technologies Changzhou Co Ltd
Current assignee: AAC Technologies Holdings Shenzhen Co Ltd; AAC Technologies Holdings Changzhou Co Ltd
Priority date: 2009-03-27
Filing date: 2009-03-27
Publication date: 2010-02-10
Anticipated expiration: 2019-03-27

Abstract

The utility model relates to the field of microphones, in particular to a MEMS microphone which comprises an upper cover plate, a shell wall and a base plate, wherein a MEMS chip is arranged in a cavity composed of the upper cover plate, the shell wall and the base plate, a baffle is arranged on the base plate, and can divide the cavity into at least two sub-cavities, a sound inlet hole and the MEMS chip are respectively arranged in different sub-cavities, the inner portion of the base plate is provided with an acoustic channel which penetrates through the base plate to communicate with a sunken acoustic cavity and the cavity with the sound inlet hole, thus sound energy can be transmitted to the back of an MEMS diaphragm through the acoustic channel, a space on the back end of the MEMS chip is used as a back acoustic cavity of the MEMS chip, thereby enabling the back acoustic cavity of the MEMS chip not to be limited by the base plate, and the enlarged back acoustic cavity is beneficial for increasing the frequency response performance and the signal-to-noise ratio of the microphone and improving the whole performances of the microphone.

Description

The MEMS microphone

[technical field]

The utility model relates to the microphone field, specifically refers to a kind of MEMS microphone.

[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, requirement is strengthened the directive property and the noise reduction capability of picking up sound, 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, as shown in Figure 1; It comprises the band sound hole 11 ~ upper cover plate 10 ~, a shell wall 20 ~, around and support upper cover plate 10 ~; One substrate 30 ~, be equipped with on it MEMS chip 50 of mutual electrical connection ~, the application-specific integrated circuit ASIC chip 40 of interior integrated preamplifier ~ and other passive components, described substrate 30 ~ supports shell wall 20 ~ with upper cover plate 10 ~; MEMS chip 50 ~ be attached to substrate 30 ~ on, thereby MEMS chip 50 ~ on a depressed part and substrate 30 ~ basal plane between form the back operatic tunes 51 of microphone ~.Above-mentioned structure that provides a kind of silica-based microphone, the MEMS chip 50 of this design ~ and substrate 30 ~ between form the back operatic tunes 51 of microphone ~ the space very limited, also very little to the contribution that performance improves, this will certainly be minimal the frequency response performance of change MEMS chip 50 ~ upper sensor self, be unfavorable for improving signal to noise ratio, in addition acoustic energy is 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.

[utility model content]

It is low that the purpose of this utility model is to solve microphone self frequency response performance, the problem that signal to noise ratio is little, and a kind of MEMS microphone that sound is advanced at the back side that increases is proposed.

A kind of MEMS microphone, comprise the upper cover plate of being with sound hole, one around and the shell wall, that supports upper cover plate support the substrate of shell wall and upper cover plate, be provided with integrated circuit (IC) chip and MEMS chip in the cavity that substrate and shell wall, upper cover plate constituted, wherein substrate is provided with dividing plate, dividing plate is divided at least two sub-cavitys with cavity, sound hole lays respectively at different sub-cavitys with the MEMS chip, the MEMS chip has the depression operatic tunes, substrate inside is provided with acoustical passage, and the depression operatic tunes communicates by this acoustical passage with sound hole.

Preferably, it is parallel with substrate that this acoustical passage has one section trend at least.

Described MEMS chip is positioned at different sub-cavitys with integrated circuit (IC) chip.

The utility model MEMS microphone, comprise upper cover plate, shell wall, substrate, the MEMS chip is installed in the cavity that it constituted, and on substrate, be provided with dividing plate, dividing plate is divided at least two sub-cavitys with cavity, sound hole lays respectively at different sub-cavitys with the MEMS chip, substrate inside is provided with an acoustical passage, acoustical passage passes substrate and connects with the depression operatic tunes and the cavity that has a sound hole respectively, acoustic energy is delivered to the back side of MEMS diaphragm from acoustical passage like this, and the space of MEMS chip rear end becomes the back operatic tunes of MEMS chip, make the back operatic tunes of MEMS chip not be subjected to the restriction of substrate, the back operatic tunes that increases helps improving the frequency response performance and the signal to noise ratio of microphone, improves the device overall performance.

[description of drawings]

Fig. 1 is the cross-sectional schematic of prior art MEMS microphone;

Fig. 2 is the cross-sectional schematic of the utility model MEMS microphone;

Fig. 3 is the cross-sectional schematic of overlooking of the utility model MEMS microphone.

[embodiment]

Describe concrete structure of the present utility model in detail below in conjunction with accompanying drawing.

The utility model MEMS microphone is mainly used on the mobile phone, receives acoustical signal and acoustical signal is converted into the signal of telecommunication.As shown in Figure 2, be the utility model one preferred embodiment, it comprise a band sound hole 11 upper cover plate 10, a shell wall 20, around and support upper cover plate 10; One substrate 30, described substrate 30 supports shell wall 20 and upper cover plate 10, and substrate 30 is combined into a cube cavity with shell wall 20, upper cover plate 10; At cavity inside, on 30 of the substrates dedicated IC chip 40 and MEMS chip 50 are installed, upper cover plate is provided with a flat dividing plate 23, the cavity that dividing plate 23 is constituted upper cover plate 10, shell wall 20, substrate 30 is separated into first cavity 21 and second cavity 22, and the sub-cavity of separating is not restricted to two certainly; Wherein the sub-cavity with sound hole 11 is second cavity 22, in establish MEMS chip 50 sub-cavity be first cavity 21, that is to say that sound hole 11 lays respectively at different cavitys with MEMS chip 50; Because the characteristics of MEMS chip 50 self structure, MEMS chip 50 is installed in and forms a depression operatic tunes 51 on substrate 30 inner surfaces, substrate 30 inside are provided with an acoustical passage 31, one end 32 of acoustical passage 31 is connected with the depression operatic tunes 51, the other end 33 is communicated with second cavity 22, sound wave is gone into from sound hole 11, through second cavity 22, be passed to MEMS chip 50 by acoustical passage 31 again, act on the back side of MEMS diaphragm, and the space of MEMS chip rear end becomes the back operatic tunes of MEMS chip, make the back operatic tunes of MEMS chip not be subjected to the restriction of substrate, this has enlarged the back operatic tunes of MEMS chip undoubtedly, clearly, the space of this back operatic tunes obviously greater than the back operatic tunes 51 of the described microphone of Fig. 1 ~ the space, then this back operatic tunes is not subjected to the restriction of substrate 30, the back operatic tunes 52 that increases makes Frequency Response and the open circuit sensitivity after the mems microphone encapsulation best, helps improving the signal to noise ratio of microphone, improves the device overall performance.

In addition, easy to be reliable for what encapsulate as shown in Figure 3, MEMS chip 50 and integrated circuit (IC) chip 40 can be positioned at different sub-cavitys, the stage casing trend of acoustical passage 31 is parallel with substrate 30, is beneficial to microphone package.

The above only is a better embodiment of the present utility model; protection range of the present utility model does not exceed with above-mentioned execution mode; as long as the equivalence that those of ordinary skills do according to the utility model institute disclosure is modified or changed, all should include in the protection range of putting down in writing in claims.

Claims

1. MEMS microphone, comprise the upper cover plate of being with sound hole, one around and the shell wall, that supports upper cover plate support the substrate of shell wall and upper cover plate, be provided with integrated circuit (IC) chip and MEMS chip in the cavity that substrate and shell wall, upper cover plate constituted, it is characterized in that: substrate is provided with dividing plate, dividing plate is divided at least two sub-cavitys with cavity, sound hole lays respectively at different sub-cavitys with the MEMS chip, the MEMS chip has the depression operatic tunes, substrate inside is provided with acoustical passage, and the depression operatic tunes communicates by this acoustical passage with sound hole.

2, MEMS microphone according to claim 1 is characterized in that: this acoustical passage has at least one section trend parallel with substrate.

3, MEMS microphone according to claim 1 is characterized in that: described MEMS chip is positioned at different sub-cavitys with integrated circuit (IC) chip.