A kind of MEMS microphoneTechnical field
The present invention relates to a kind of MEMS microphone.
Background technology
MEMS microphone is the acoustic-electrical transducer that a kind of micromachining technology is made, the features such as volume is little, good frequency response, noise are low that it has.Along with compact, the slimming development of electronic equipment, MEMS microphone is applied on these equipment more and more widely.
A MEMS chip based on capacitance detecting and an asic chip is comprised in MEMS microphone product, the electric capacity of MEMS chip can produce corresponding change along with the difference of input audio signal, and the capacitance signal of recycling asic chip to change processes and export thus realize the pickup to sound.MEMS chip generally includes the substrate with back of the body chamber, the plane-parallel capacitor be made up of back pole plate and vibrating diaphragm arranged above substrate, vibrating diaphragm receives extraneous voice signal and vibrates, thus make plane-parallel capacitor produce the signal of telecommunication of a change, realize sound-electric translation function.
At present more and more higher for the requirement of the signal to noise ratio of MEMS microphone product, can realize this purpose by the capacity area increasing MEMS chip in theory, but this needs again to develop, designs, makes a new MEMS chip, cost and difficulty are all very high.
Summary of the invention
The object of this invention is to provide a kind of new technical scheme utilizing the MEMS microphone of existing MEMS chip increasing detection capacitance area.
The present invention proposes a kind of MEMS microphone, comprising: wiring board, be arranged at support portion above wiring board, be arranged at one MEMS chip above support portion and shell; Described wiring board and shell surround cavity, and described support portion and one MEMS chip are encapsulated in inside cavity; Described one MEMS chip comprises the first MEMS unit arranged side by side and the second MEMS unit; Described wiring board offers the first through hole; Described support portion corresponds to the first MEMS unit and offers the second through hole, and offers third through-hole corresponding to the second MEMS unit; Described first through hole is between the second through hole and third through-hole, and described first, second, third through hole interconnects the acoustic aperture forming fork.
Preferably, described support portion is silicon chip.
Preferably, described first MEMS unit and the second MEMS unit are respectively differential capacitance structure, comprise respectively: be positioned at middle vibrating diaphragm, the second back pole plate being positioned at the first back pole plate above vibrating diaphragm and being positioned at below vibrating diaphragm.
Preferably, the one side that described wiring board contacts with support portion offers the first groove, and described first groove is communicated with described first, second, third through hole to form the acoustic aperture of described fork.
Preferably, the one side that described support portion contacts with wiring board offers the second groove, and described second groove is communicated with described first, second, third through hole to form the acoustic aperture of described fork.
Preferably, the one side that described wiring board contacts with support portion offers the first groove, and the one side that described support portion contacts with wiring board offers second groove relative with described first groove; Described first groove is communicated with described first, second, third through hole to form the acoustic aperture of described fork with the second groove.
Preferably, the asic chip be arranged on wiring board is also comprised; Described first MEMS unit and the second MEMS unit are electrically connected with described asic chip by adapter, or described first MEMS unit and the second MEMS unit are electrically connected with described asic chip by the circuit on wiring board.
Preferably, also comprise an asic chip be arranged on wiring board, described first MEMS unit and the second MEMS unit share described asic chip.
Preferably, described first MEMS unit and the parallel connection of the second MEMS unit.
Simultaneously the manufacture process of MEMS chip forms multiple MEMS unit then formation MEMS chip one by one to be separated in one one cutting.According to technical scheme of the present invention, only need when cutting, two MEMS unit to be retained in together, form an one MEMS chip, just can utilize the area of existing MEMS unit increasing detection capacitance, and without the need to again developing the MEMS chip of a large Detection capacitance area.MEMS microphone of the present invention utilizes the area of existing MEMS unit increasing detection capacitance, improves the signal to noise ratio of MEMS microphone, thus improves the performance of microphone products.
The present inventor finds, does not still have a kind of MEMS microphone utilizing existing MEMS chip increasing detection capacitance area in the prior art.Therefore the present invention is a kind of new technical scheme.
By referring to the detailed description of accompanying drawing to exemplary embodiment of the present invention, further feature of the present invention and advantage thereof will become clear.
Accompanying drawing explanation
In the description combined and the accompanying drawing forming a part for specification shows embodiments of the invention, and illustrate that one is used from and explains principle of the present invention together with it.
Fig. 1 is the structural representation of the embodiment of MEMS microphone of the present invention.
Fig. 2 is the vertical view of the wiring board of Fig. 1 embodiment.
Fig. 3 is the end view of the wiring board of Fig. 1 embodiment.
Fig. 4 is the upward view of the support portion of Fig. 1 embodiment.
Fig. 5 is the end view of the support portion of Fig. 1 embodiment.
Fig. 6 is the schematic diagram of the MEMS chip of MEMS microphone of the present invention and the first embodiment of asic chip connected mode.
Fig. 7 is the schematic diagram of the MEMS chip of MEMS microphone of the present invention and the second embodiment of asic chip connected mode.
Embodiment
Various exemplary embodiment of the present invention is described in detail now with reference to accompanying drawing.It should be noted that: unless specifically stated otherwise, otherwise positioned opposite, the numerical expression of the parts of setting forth in these embodiments and step and numerical value do not limit the scope of the invention.
Illustrative to the description only actually of at least one exemplary embodiment below, never as any restriction to the present invention and application or use.
May not discuss in detail for the known technology of person of ordinary skill in the relevant, method and apparatus, but in the appropriate case, technology, method and apparatus should be regarded as a part for specification.
In all examples with discussing shown here, any occurrence should be construed as merely exemplary, instead of as restriction.Therefore, other example of exemplary embodiment can have different values.
It should be noted that: represent similar terms in similar label and letter accompanying drawing below, therefore, once be defined in an a certain Xiang Yi accompanying drawing, then do not need to be further discussed it in accompanying drawing subsequently.
The structure of the embodiment of MEMS microphone of the present invention is introduced with reference to figure 1-5:
MEMS microphone, comprises wiring board 100, is arranged at support portion 200 above wiring board 100, is arranged at one MEMS chip 300 above support portion 200 and shell 1.Wiring board 100 and shell 1 surround cavity, and support portion 200 and one MEMS chip 300 are encapsulated in inside cavity.
One MEMS chip 300 comprises the first MEMS unit 301 and the second MEMS unit 302 arranged side by side, first MEMS unit 301 has a MEMS capacitance structure, second MEMS unit 302 has the 2nd MEMS capacitance structure, the first MEMS unit 301 and the parallel connection of the second MEMS unit 302.
Wiring board 100 offers the first through hole 102; Support portion 200 corresponds to the first MEMS unit 301 and offers the second through hole 202, and offers third through-hole 203 corresponding to the second MEMS unit.First through hole 102 is between the second through hole 202 and third through-hole 203, and first, second, third through hole 102,202,203 interconnects the acoustic aperture forming fork.One MEMS chip 300 and shell 1, wiring board 100 surround the rear operatic tunes 400 jointly.The setting of above-mentioned acoustic aperture, can make the sound wave entering into two MEMS unit more even, makes two MEMS unit more be equivalent to the MEMS unit of a large Detection capacitance area; The demand entering sound below microphone can also be met simultaneously, and provide certain protection to MEMS chip, prevent dust or solid particle from entering MEMS chip inside and vibrating diaphragm is damaged.
An above-mentioned MEMS capacitance structure and the 2nd MEMS capacitance structure can be respectively differential capacitance structure, comprise respectively: be positioned at middle vibrating diaphragm, the second back pole plate being positioned at the first back pole plate above vibrating diaphragm and being positioned at below vibrating diaphragm.Multiple through hole can be set respectively in the sensing part of the first back pole plate and the second back pole plate, and the center of vibrating diaphragm is provided with some tiny through holes, to play the effect of operatic tunes acoustic pressure before and after balance.
In the present embodiment, the one side that wiring board 100 contacts with support portion 200 offers the first groove 101, and the one side that support portion 200 contacts with wiring board 100 offers second groove 201 relative with the first groove 101; First groove 101 is communicated with first, second, third through hole 102,202,203 to form the acoustic aperture of fork with the second groove 201.In other embodiments, the one side that can only contact with support portion 200 at wiring board 100 offers the first groove 101, first groove 101 and is communicated with first, second, third through hole 102,202,203 to form the acoustic aperture diverged; The one side that also can only contact with wiring board 100 in support portion 200 offers the second groove 201, second groove 201 and is communicated with first, second, third through hole 102,202,203 to form the acoustic aperture diverged.
MEMS microphone also comprises the asic chip (not illustrating in Fig. 1-5) be arranged on wiring board 100, in the present embodiment, two MEMS unit share an asic chip, in other embodiments, two MEMS unit can use an asic chip respectively.
Wherein, support portion 200 can be silicon chip.First back pole plate, vibrating diaphragm, the second back pole plate can be polysilicon material; Or the first back pole plate, vibrating diaphragm, the second back pole plate include silicon nitride layer and polysilicon layer; Or the first back pole plate, vibrating diaphragm, the second back pole plate include silicon nitride layer and metal level; Wherein silicon nitride layer mainly plays a supportive role, and polysilicon layer or metal level use as the pole plate of electric capacity.
Fig. 6 is the schematic diagram of the MEMS chip of MEMS microphone of the present invention and the first embodiment of asic chip connected mode.As can be seen from Figure 6, the first MEMS unit 301 and the second MEMS unit 302 are electrically connected with asic chip 600 by the circuit on wiring board 100.
Fig. 7 is the schematic diagram of the MEMS chip of MEMS microphone of the present invention and the second embodiment of asic chip connected mode.As can be seen from Figure 7, MEMS microphone also comprises an adapter 800, adapter 800 is provided with circuit, first MEMS unit 301, second MEMS unit 302, asic chip 600 are connected to adapter 800 respectively, and the first MEMS unit 301 and the second MEMS unit 302 are electrically connected with asic chip 600 by the circuit on adapter 800.
Simultaneously the manufacture process of MEMS chip forms multiple MEMS unit then formation MEMS chip one by one to be separated in one one cutting.According to technical scheme of the present invention, only need when cutting, two MEMS unit to be retained in together, form an one MEMS chip, just can utilize the area of existing MEMS unit increasing detection capacitance, and without the need to again developing the MEMS chip of a large Detection capacitance area.MEMS microphone of the present invention utilizes the area of existing MEMS unit increasing detection capacitance, improves the signal to noise ratio of MEMS microphone, thus improves the performance of microphone products.
Although be described in detail specific embodiments more of the present invention by example, it should be appreciated by those skilled in the art, above example is only to be described, instead of in order to limit the scope of the invention.It should be appreciated by those skilled in the art, can without departing from the scope and spirit of the present invention, above embodiment be modified.Scope of the present invention is defined by the claims.