阅读说明：本技术 一种mems结构 (A kind of MEMS structure ) 是由 刘端 于 2019-10-11 设计创作，主要内容包括：本申请公开了一种MEMS结构,包括：衬底,具有空腔；压电复合振动层,包括固定端和自由端,所述固定端连接至位于所述空腔的第一侧的衬底材料上方,所述自由端悬挂在所述空腔的第二侧的衬底材料上方,所述压电复合振动层覆盖所述空腔,所述空腔的第一侧和第二侧相对设置；防漏声限位件,位于所述自由端上方并且阻挡限制所述压电复合振动层的所述自由端的偏转。基于本申请所提供的MEMS结构,能够实现对压电复合振动层的限位,降低振动梁大幅度弯曲而折断的几率,提高MEMS结构的可靠性。另一方面,防漏声限位件增大了声阻,减小了低频漏声。(This application discloses a kind of MEMS structures, comprising: substrate has cavity；Piezoelectric anisotropy vibration level, including fixing end and free end, the fixing end is connected to above the substrate material of the first side of the cavity, the free end is suspended on above the substrate material of second side of the cavity, the Piezoelectric anisotropy vibration level covers the cavity, and the first side of the cavity and second side are oppositely arranged；Leakproof sound locating part above the free end and stops the deflection for limiting the free end of the Piezoelectric anisotropy vibration level.Based on MEMS structure provided herein, the limit to Piezoelectric anisotropy vibration level can be realized, reduce the probability that walking beam is significantly bent and fractures, improve the reliability of MEMS structure.On the other hand, leakproof sound locating part increases acoustic resistance, reduces low frequency leakage sound.)

1. a kind of MEMS structure characterized by comprising

Substrate has cavity；

Piezoelectric anisotropy vibration level, including fixing end and free end, the fixing end are connected to positioned at the first side of the cavity Above substrate material, the free end is suspended on above the substrate material of second side of the cavity, the Piezoelectric anisotropy vibration Layer covers the cavity, and the first side of the cavity and second side are oppositely arranged；

Leakproof sound locating part above the free end and stops the free end for limiting the Piezoelectric anisotropy vibration level Deflection.

2. MEMS structure according to claim 1, which is characterized in that the Piezoelectric anisotropy vibration level includes:

First electrode layer is formed on the substrate；

First piezoelectric layer is formed in above the first electrode layer；

The second electrode lay is formed in above first piezoelectric layer.

3. MEMS structure according to claim 2, which is characterized in that the Piezoelectric anisotropy vibration level further include:

Supporting layer is vibrated, is formed between the substrate and the first electrode layer.

4. MEMS structure according to claim 2, which is characterized in that the Piezoelectric anisotropy vibration level further include:

Second piezoelectric layer is formed in above the second electrode lay；

Third electrode layer is formed in above second piezoelectric layer.

5. MEMS structure according to claim 1, which is characterized in that the thickness of the substrate material of the first side of the cavity Equal to the thickness of the substrate material of second side of the cavity, the MEMS structure further includes the connection above the substrate Supporting layer, the fixing end are connect by the connection supporting layer with the substrate.

6. MEMS structure according to claim 1, which is characterized in that the thickness of the substrate material of the first side of the cavity Greater than the thickness of the substrate material of second side of the cavity, the fixing end is connected directly to positioned at the first side of the cavity Substrate material above, the free end is hung on above the substrate material of second side of the cavity.

7. MEMS structure according to claim 1, which is characterized in that the free end is located at the substrate and the leakproof Between sound locating part, and the free end and the leakproof sound locating part have overlapping region in vertical direction.

8. MEMS structure according to claim 1, which is characterized in that the leakproof sound locating part is around the Piezoelectric anisotropy The free end of vibration level；Or the leakproof sound locating part only covers the free end of the Piezoelectric anisotropy vibration level A part.

9. MEMS structure according to claim 2, which is characterized in that the first electrode layer and the second electrode lay point Multiple subregions that Ju You be not mutually isolated, the material of the first electrode layer of same subregion and the material of the second electrode lay Electrode layer pair is constituted, the electrode layer between different subregions is to being sequentially connected in series.

10. MEMS structure according to claim 4, which is characterized in that the first electrode layer, the second electrode lay and The third electrode layer has at least two mutually isolated subregions, the material of the first electrode layer in same subregion and institute It states and constitutes electrode layer pair, the different by stages with the material of the second electrode lay after the material electrical connection of third electrode layer The electrode layer to being sequentially connected in series.

11. MEMS structure according to claim 4, which is characterized in that the first electrode layer, the second electrode lay and The third electrode layer has at least two mutually isolated subregions, the material of the first electrode layer in same subregion and institute The material for stating the second electrode lay constitutes first electrode layer pair and the material of the second electrode lay and the third electrode layer Material constitutes the second electrode lay pair, and the first electrode layer pair and the second electrode lay are to composition electrode layer string after connecting, no The electrode layer string with the by stages is sequentially connected in series.

Technical field

This application involves technical field of semiconductors, it particularly relates to a kind of MEMS (Microelectro Mechanical Systems's writes a Chinese character in simplified form, i.e. MEMS) structure.

Background technique

MEMS microphone (microphone) mainly includes condenser type and two kinds of piezoelectric type.MEMS piezoelectric microphone is to utilize micro- electricity The microphone of sub- mechanical system technique and the preparation of piezoelectric membrane technology, due to using skills such as semiconductor planar technique and silicon bulk fabrications Art, so its size is small, small in size, consistency is good.Bias voltage, work temperature are not needed also relative to condenser microphone simultaneously It is big to spend range, the advantages that dust-proof, waterproof.

But when acoustic pressure is too big or other external causes cause the walking beam of MEMS piezoelectric microphone to be significantly bent, hold Walking beam is easily caused to fracture damage, to influence the reliability of MEMS piezoelectric microphone.Also, existing MEMS piezoelectric microphone Also it be easy to cause low frequency leakage sound.

For the lower problem of the reliability of MEMS piezoelectric microphone in the related technology, effective solution is not yet proposed at present Scheme.

Summary of the invention

For the lower problem of the reliability of MEMS piezoelectric microphone in the related technology, the application proposes a kind of MEMS knot Structure can be improved the reliability of MEMS piezoelectric microphone.

The technical solution of the application is achieved in that

According to the one aspect of the application, a kind of MEMS structure, including substrate are provided, there is cavity；Piezoelectric anisotropy vibration Dynamic layer, including fixing end and free end, the fixing end are connected to above the substrate material of the first side of the cavity, institute Above the substrate material for stating second side that free end is suspended on the cavity, the Piezoelectric anisotropy vibration level covers the cavity, First side of the cavity and second side are oppositely arranged；Leakproof sound locating part above the free end and stops to limit The deflection of the free end of the Piezoelectric anisotropy vibration level.

Wherein, the Piezoelectric anisotropy vibration level includes: first electrode layer, is formed on the substrate；First piezoelectric layer, It is formed in above the first electrode layer；The second electrode lay is formed in above first piezoelectric layer.

Wherein, the Piezoelectric anisotropy vibration level further include: vibration supporting layer is formed in the substrate and the first electrode Between layer.

Wherein, the Piezoelectric anisotropy vibration level further include: the second piezoelectric layer is formed in above the second electrode lay；The Three electrode layers are formed in above second piezoelectric layer.

Wherein, the thickness of the substrate material of the first side of the cavity is equal to the substrate material of second side of the cavity Thickness, the MEMS structure further include the connection supporting layer above the substrate, and the fixing end passes through connection branch Support layer is connect with the substrate.

Wherein, the thickness of the substrate material of the first side of the cavity is greater than the substrate material of second side of the cavity Thickness, the fixing end are connected directly to above the substrate material of the first side of the cavity, and the free end is hung on Above the substrate material of second side of the cavity.

Wherein, the free end is between the substrate and the leakproof sound locating part, and the free end and institute State leakproof sound locating part has overlapping region in vertical direction.

Wherein, the leakproof sound locating part is around the free end of the Piezoelectric anisotropy vibration level；Or the leakproof Sound locating part only covers a part of the free end of the Piezoelectric anisotropy vibration level.

Wherein, the first electrode layer and the second electrode lay are respectively provided with mutually isolated multiple subregions, and same point The material of the first electrode layer in area and the material of the second electrode lay constitute electrode layer pair, described between different subregions Electrode layer is to being sequentially connected in series.

Wherein, the first electrode layer, the second electrode lay and the third electrode layer have at least two mutually every From subregion, after the material electrical connection of the material and the third electrode layer of the first electrode layer in same subregion with institute The material for stating the second electrode lay constitutes electrode layer pair, and the electrode layers of the different by stages is to being sequentially connected in series.

Wherein, the first electrode layer, the second electrode lay and the third electrode layer have at least two mutually every From subregion, the material of the first electrode layer in same subregion and the material of the second electrode lay constitute first electrode layer Pair and the material of the material of the second electrode lay and the third electrode layer constitute the second electrode lay pair, the first electrode Layer is successively gone here and there to the second electrode lay to electrode layer string, the electrode layer string of the different by stages is constituted after connecting Connection.

Based on MEMS structure provided herein, the limit to Piezoelectric anisotropy vibration level can be realized, reduce walking beam The probability to fracture because being significantly bent improves the reliability of MEMS structure.On the other hand, leakproof sound locating part increases sound Resistance, reduces low frequency leakage sound.

Detailed description of the invention

In order to illustrate the technical solutions in the embodiments of the present application or in the prior art more clearly, below will be to institute in embodiment Attached drawing to be used is needed to be briefly described, it should be apparent that, the accompanying drawings in the following description is only some implementations of the application Example, for those of ordinary skill in the art, without creative efforts, can also obtain according to these attached drawings Obtain other attached drawings.

When reading in conjunction with the accompanying drawings, each side of the application may be better understood according to the following detailed description Face.It is emphasized that all parts are not drawn on scale, and are for illustration purposes only according to the standard practices of industry.It is real On border, in order to clearly discuss, the size of all parts can arbitrarily increase or reduce.

Fig. 1 is the schematic cross-section according to the MEMS structure of some embodiments of the present application；

Fig. 2 is the schematic cross-section according to the MEMS structure of some embodiments of the present application；

Fig. 3 is the top view according to the MEMS structure of some embodiments of the present application.

Specific embodiment

Below in conjunction with the attached drawing in the embodiment of the present application, technical solutions in the embodiments of the present application carries out clear, complete Site preparation description, it is clear that described embodiments are only a part of embodiments of the present application, instead of all the embodiments.It is based on Embodiment in the application, those of ordinary skill in the art's every other embodiment obtained belong to the application protection Range.

Following disclosure provides many different embodiments or example to realize the different characteristic of the application.Below will The particular instance of element and arrangement is described to simplify the application.Certainly these are only that example is not intended to be limiting.For example, element Size is not limited to disclosed range or value, but performance needed for possibly relying on process conditions and/or device.In addition, with In lower description, above second component or the upper formation first component may include that the first component and second component directly contact shape At embodiment, and also may include additional component can be formed between the first component and second component so that The embodiment that the first component and second component can be not directly contacted with.It, can be any in different sizes in order to simplified and clear Draw all parts in ground.

In addition, for ease of description, spatially relative term such as " ... under (beneath) ", " in ... lower section (below) ", " lower part (lower) ", " ... on (above) ", " top (upper) " etc. can be used for describing herein it is attached The relationship of an element or component shown in figure and another (or other) element or component.Spatially relative term is intended to wrap It includes other than orientation shown in the drawings, the different direction of the device in use or in operation.Device can be otherwise Orientation (be rotated by 90 ° or in other directions), spatial relative descriptor used herein can similarly make respective explanations.In addition, Term " by ... be made " can mean " comprising " or " by ... form ".

According to an embodiment of the present application, a kind of MEMS structure is provided, microphone or microphone are applied to and is had good Good reliability.

As depicted in figs. 1 and 2, according to the MEMS structure of the embodiment of the present application, including substrate 10, Piezoelectric anisotropy vibration level 20 With leakproof sound locating part 30.Each component part will be described in detail below.

Substrate 10 includes silicon or any suitable silicon base compound or derivative (such as silicon wafer, SOI, SiO₂On/Si Polysilicon).Substrate 10 has cavity 11, and DRIE (deep reactive ion etch) or wet etching can be used to form cavity 11.

Piezoelectric anisotropy vibration level 20 is formed above substrate 10.Piezoelectric anisotropy vibration level 20 includes fixing end A and free end B, fixing end A are connected to above the substrate material of the first side of cavity 11, and free end B is suspended on second side of cavity 11 Above substrate material, the first side of cavity 11 and second side are oppositely arranged, and Piezoelectric anisotropy vibration level 20 covers cavity 11.In other words It says, Piezoelectric anisotropy vibration level 20 forms cantilever beam structure, to vibrate under acoustic pressure effect.

Forming the cantilever beam structure with fixing end A and free end B may include two methods.A kind of method is in substrate 10 tops form connection supporting layer 40, and the thickness of the substrate material of the first side of cavity 11 is equal to the substrate of second side of cavity 11 The thickness of material, fixing end A are connect by connecting supporting layer 40 with substrate 10.The material for connecting supporting layer 40 includes to poly- diformazan Benzene, polyimides, SiN, SiO₂, polysilicon.Another method is etching part substrate 10 or applies sacrificial layer, so that cavity 11 The first side substrate material thickness be greater than cavity 11 second side substrate material thickness, fixing end A is connected directly to On the substrate material of the first side of cavity 11, so that free end B hangs on the substrate material of second side of cavity 11 Top.

Piezoelectric anisotropy vibration level 20 includes vibration supporting layer 21, first electrode layer 22, the first piezoelectric layer 23, the second electrode lay 24.Vibration supporting layer 21 is formed in 10 top of substrate, and first electrode layer 22 is formed in 21 top of vibration supporting layer, the first piezoelectric layer 23 are formed in 22 top of first electrode layer, and the second electrode lay 24 is formed in 23 top of the first piezoelectric layer.Vibrating supporting layer 21 includes Silicon nitride (Si₃N₄), the single layer that constitutes of silica, monocrystalline silicon, polysilicon or MULTILAYER COMPOSITE membrane structure or other suitable support Material.In view of the stress problem of control vibration supporting layer 21, multilayered structure can be set to reduce by vibration supporting layer 21 Stress.The method for forming vibration supporting layer 21 includes thermal oxidation method or chemical vapour deposition technique.First electrode layer 22, the first piezoelectricity Layer 23 and the second electrode lay 24 constitute Piezoelectric anisotropy layer.First piezoelectric layer 23 can be by the pressure conversion of application at voltage, the first electricity Generated voltage can be sent to other integrated circuit device by pole layer 22 and the second electrode lay 24.In some embodiments, The material of one piezoelectric layer 23 include zinc oxide, aluminium nitride, organic piezoelectric film, lead zirconate titanate (PZT), in perouskite type piezoelectric film One or more layers or other suitable material.The method for forming the first piezoelectric layer 23 includes magnetron sputtering method or other are suitable Method.The material of first electrode layer 22 and the second electrode lay 24 include aluminium, gold, platinum, molybdenum, titanium, chromium and they form it is compound Film or other suitable materials.The method for forming first electrode layer 22 and the second electrode lay 24 include physical vapour deposition (PVD) or other Suitable method.

It in some embodiments, can be on the second electrode lay 24 in the embodiment for being not provided with vibration supporting layer 21 Side sequentially forms the second piezoelectric layer (not shown) and third electrode layer (not shown).Therefore, the piezoelectricity of MEMS structure Composite layer has first electrode layer 22, the first piezoelectric layer 23, the second electrode lay 24, the second piezoelectric layer and third electrode layer, thus Double wafer structure is constituted, the piezoelectricity transfer efficiency of MEMS structure is improved.The material of second piezoelectric layer includes zinc oxide, nitridation Aluminium, organic piezoelectric film, lead zirconate titanate (PZT), one or more layers or other suitable material in perouskite type piezoelectric film.The The material and forming method and the material and forming method of the first piezoelectric layer 23 of two piezoelectric layers may be the same or different.The The material of three electrode layers includes aluminium, gold, platinum, molybdenum, titanium, chromium and composite membrane that they are formed or other suitable materials.Third The material of electrode layer and the material and forming method of forming method and first electrode layer 22 may be the same or different.

Leakproof sound locating part 30 is located above the B of free end and stops the free end B's for limiting Piezoelectric anisotropy vibration level 20 Deflection.The material of leakproof sound locating part 30 includes to polyxylene, polyimides, SiN, SiO₂, polysilicon.Free end B is located at Between substrate 10 and leakproof sound locating part 30, and free end B and leakproof sound locating part 30 have overlay region in vertical direction Domain.Leakproof sound locating part 30 only covers piezoelectricity around the free end B or leakproof sound locating part 30 of Piezoelectric anisotropy vibration level 20 and answers Close a part of the free end B of vibration level 20.Leakproof sound locating part 30 includes first part and second part, first part and lining Bottom 10 is in contact, and second part is connected with first part and for stopping the free end B of Piezoelectric anisotropy vibration level 20 to deflect.

As shown in figure 3, the setting about electrode layer, this application provides a kind of possible embodiments.For example, multiple in piezoelectricity It closes in embodiment of the vibration level 20 only with first electrode layer 22 and the second electrode lay 24, first electrode layer 22 and the second electrode lay 24 are respectively provided with mutually isolated multiple subregions, and the first electrode layer 22 and the second electrode lay 24 of same subregion constitute electrode layer Right, the electrode layer between different subregions is exported voltage caused by MEMS structure by lead to being sequentially connected in series.

There is first electrode layer 22, the embodiment of the second electrode lay 24 and third electrode layer in Piezoelectric anisotropy vibration level 20 In, first electrode layer 22, the second electrode lay 24 and third electrode layer have at least two mutually isolated subregions, in same subregion First electrode layer 22 material and third electrode layer material electrical connection after with the material of the second electrode lay 24 constitute electrode Layer is to (electrode layer in i.e. same subregion is to parallel connection), and electrode layer between different subregions is to being sequentially connected in series；Or in same subregion The material of first electrode layer 22 and the material of the second electrode lay 24 constitute first electrode layer pair, and the material of the second electrode lay 24 Material and the material of third electrode layer composition the second electrode lay are to (electrode layer to connect) in i.e. same subregion, first electrode layer pair It is sequentially connected in series with the second electrode lay to electrode layer string, the electrode layer string between different subregions is constituted after connecting.

Based on MEMS structure provided herein, the limit to Piezoelectric anisotropy vibration level 20 can be realized, reduce vibration Dynamic beam is significantly bent and the probability that fractures, improves the reliability of MEMS structure.On the other hand, leakproof sound locating part 30 increases Acoustic resistance, reduces low frequency leakage sound.

The above is only the preferred embodiments of the application, not to limit the application, it is all in spirit herein and Within principle, any modification, equivalent replacement, improvement and so on be should be included within the scope of protection of this application.