CN207265035U - A kind of accurate floated MEMS chip encapsulating structure of central supported - Google Patents

Abstract

The utility model discloses a kind of accurate floated MEMS chip encapsulating structure of central supported, it is characterized in that, the bottom electrode of MEMS chip is fixed on silica separation layer, and silica separation layer is fixed on a silicon substrate；The top electrode of MEMS chip is suspended in above bottom electrode by center anchor point structural support；The silicon substrate viscose glue of MEMS chip or bonding are fixed on ceramic cartridge cavity bottom surface, and silicon substrate is etched to only be supported by a central support structure and is connected with ceramic cartridge cavity.MEMS chip approximation suspension support can significantly be reduced the encapsulation stress in MEMS chip, realize the low stress encapsulation of MEMS chip in encapsulating package bottom surface by the central support structure that processes on a silicon substrate.The structure has that packaging technology is simple, does not dramatically increase packaging cost without in the extra one layer of special stress isolation structure sheaf of increase in silicon substrate bottom, therefore former package thickness being kept constant, it is easy to accomplish the advantages of.

Description

A kind of accurate floated MEMS chip encapsulating structure of central supported

Technical field

The present invention relates to electronic field, and in particular to a kind of accurate Floating MEMS capacitance sensors using central supported Low stress encapsulates.

Background technology

MEMS（Micro Electro Mechanical System）Capacitance sensor has small, light weight, power consumption The low, advantage such as cost is low, is widely used.MEMS capacitance sensors are by measuring the capacitance variations of small sensitive structure composition come real The now measurement of corresponding measured physical quantity.Usual MEMS sensor need to be encapsulated in certain structure, to provide needed for sensor Electrical connection, mechanical connection and corresponding chemical environment protection etc..

Metal Packaging, Plastic Package and ceramic package are the packing forms of most common three kinds of MEMS chips.Due to ceramics Encapsulation have the advantages that thermal conductivity, air-tightness are good, therefore ceramic package use it is the most extensive.

The encapsulating structure of the MEMS sensor of usual ceramic package is as shown in Figure 1.Traditional MEMS capacitance sensor adds first Work goes out MEMS sensor bare chip 100, is then fixed on by way of viscose glue or bonding 500 in 200 cavity of ceramic cartridge.It is naked Pad on chip is connected with each other with the pad in ceramic cartridge cavity by metal lead wire 300, realizes electric signal in shell Outer mutual transmission.200 cavity of ceramic cartridge is finally sealed using kovar alloy cover board 400.But whether ceramic package is also Be Metal Packaging also or Plastic Package, it is different from the thermal coefficient of expansion of silicon materials there is encapsulating material all the time, therefore temperature Change can produce encapsulation stress.Encapsulation stress can have an impact the precision and stability of sensor.How encapsulation stress is reduced, It is the emphasis and difficult point of high-precision MEMS capacitance sensors design.

Application for a patent for invention《MEMS inertial sensor encapsulating structure with stress isolation》（Application number 201020124304.6）It is proposed by being bonded one layer of material identical with sensor substrate between sensor chip and encapsulating package Stress isolation layer, realize the stress isolation to MEMS inertial sensor chip.Application for a patent for invention《Encapsulation stress can be reduced Packaging structure》（Application number 200810083425.8）Propose a kind of comprising carrier, intermediary substrate, the first fluid sealant and the A kind of construction of reduction chip package stress of two fluid sealants.This method is close by coating first between chip and intermediary substrate Sealing, coats the second fluid sealant between intermediary substrate and carrier, selects the glass transition temperature of the first fluid sealant to be more than the The glass transition temperature of two fluid sealants, realizing reduces encapsulation stress.

Freescale Semiconductor proposes the technological approaches of some improvement encapsulation stress.Application for a patent for invention《Have Compensate the capacitance sensor of the stress elimination of encapsulation stress》（Application number 200980119818.2）One kind is proposed in MEMS capacitances The end of moving element processes the line of rabbet joint towards rotation axis extension in formula sensor, realizes that compensation encapsulation stress improves sensors The purpose of energy.Application for a patent for invention《Reduce the semiconductor devices to the sensitiveness of encapsulation stress》（Application number 200980120339.2）Proposing includes the position being arranged symmetrically and refer to anchor by fixing of element by differential capacitive transducer The foundation in the anchor region of definition is put, is located at for displaceable element or the suspension anchor for detecting mass block in the anchor region, can be with The nonlinear component of displacement is effectively eliminated, and then reduces the influence that encapsulation stress exports sensor.Application for a patent for invention《Tool It is useful for the MEMS device of the central anchor of stress isolation》It is proposed to substantially reduce element to base by the device relative to the prior art The connection of plate and by make these connection be located at each other very close in the range of and at the central part of substrate, realization subtracts The purpose of small stress.

Application for a patent for invention《A kind of floated force-sensing sensor chip for eliminating encapsulation stress and preparation method thereof》（Application Numbers 201210333367.6）And application for a patent for invention《Encapsulation stress and the self-compensating dual suspension force-sensing sensor chip of temperature drift and Preparation method》（Application number 201310234503.0）Be pressure sensor is integrated in using a kind of design and manufacturing process it is outstanding On arm girder construction band, the mechanical characteristic of cantilever tail beam freedom of movement structure is fully relied on, makes the pressure sensor on cantilever beam The adverse effect that chip exterior encapsulation stress is brought to force-sensing sensor performance can effectively be suppressed.

Application for a patent for invention《A kind of accelerometer and its manufacturing process》（Application number 201210356535.3）It is special with invention Profit application《A kind of accelerometer and its manufacturing process》（Application number 201210356922.7）It is proposed that the mass block of accelerometer leads to Cross different spring beams with frame to be connected, frame is being connected by four cantilever beams with movable limit body, so as to fulfill knot The encapsulation stress isolation of structure.

Application for a patent for invention《Chip is attached stress isolation》（Application number 201310016701.X）It is proposed is used for using one kind The stress isolation bracket of micro-structured devices, it includes bracket base and has the first bracket arm and the second bracket arm, the first support Boom is used to be attached to micro-structured devices and opposite relative to the first inward-facing installation surface of the passage, the second bracket arm In the passage towards externally to be attached to the second installation surface of the encapsulation for accommodating micro-structured devices.

Application for a patent for invention《Pass through the method for back-patterned reduction MEMS chip encapsulation stress》（Application number 201310140175.8）It is proposed be used as by photoetching offset plate figure and etch the film that salts down the back layer of MEMS chip is performed etching, formation Load column.Bonding die glue is coated on the bottom plate of encapsulating package, the MEMS chip with load column is fixed on envelope by load column On the shell bottom plate of tubulature, and then realize the purpose for reducing encapsulation stress.

Application for a patent for invention《A kind of MEMS sensor encapsulating structure and its method for packing》（Application number 201410183524.9）It is proposed to select with the close ceramic bases of MEMS sensor material thermal expansion coefficient as encapsulating material, Realize the influence for reducing pedestal swelling stress to MEMS sensor.Application for a patent for invention《The encapsulating structure and envelope of MEMS sensor Dress method》（Application number 201510441722.5）It is proposed the thermal coefficient of expansion using silicon nitride ceramic material and the close spy of silicon Point, selects pedestal of the silicon nitride ceramics as package of MEMS sensor chip, realizes the purpose for reducing encapsulation stress.

Application for a patent for invention《A kind of pressure sensor of the insulation package stress based on Si-Si bonding》（Application number 201410306360.4）And application for a patent for invention《A kind of micro-mechanical gyroscope of the reduction encapsulation stress based on Si-Si bonding》 （Application number 201410816214.6）It is to propose to etch one piece of convex block for being used for Si-Si bonding in support layer surface, will senses Device chip is fixed on the convex block of support layer surface by Si-Si bonding.By reduce bonding area and deep plough groove etched reduction because The thermal stress that material thermal expansion coefficient is mismatched and produced.

Application for a patent for invention《A kind of MEMS device thermal stress isolation structure》（Application number 201410465729.6）Propose A kind of MEMS device thermal stress isolation structure.The structure corner is respectively equipped with a raised bonding face and MEMS device substrate silicon Silicon bonding, heat insulation structural middle part form the cavity of perforation, and radiating groove that is crisscross and penetrating through is equipped with cavity.By using this Thermal stress isolation structure can reduce influence of the encapsulation stress to MEMS device.

Application for a patent for invention《A kind of LCC encapsulation stress discharges structure》（Application number 201410720844.3）It is proposed it is a kind of with The LCC encapsulation stress release structure of chip form fit.The structure setting anchor point and supporting point, pass through between anchor point and supporting point Tie-beam connects.LCC encapsulation can effectively be reduced by the structure and pass to the thermal stress of chip.

Application for a patent for invention《The manufacture method and its MEMS chip of the MEMS chip insensitive to encapsulation stress》（Application number 201510114611.3）Propose a kind of MEMS chip manufacture method insensitive to encapsulation stress.Produced using this method Bottom electrode and MEMS bascules be sealed in an annular seal space, and the contact of bottom electrode and MEMS bascules with bottom plate Area is all very small, therefore only some thermal stress is transmitted on bottom electrode and MEMS bascules.

Application for a patent for invention《A kind of MEMS device and preparation method thereof》（Application number 201510365845.5）It is proposed passes through An independent isolation structure is added in MEMS device lower part to realize the purpose of reduction thermal stress.

Application for a patent for invention《A kind of preparation method of low stress accelerometer》（Application number 201510661783.2）It is proposed The fixed electrode structure of tradition is changed into the clamped suspension electrode structure of both-end so that thermal stress is under the influence significantly of electrode structure Drop, so as to fulfill the purpose of the full warm nature energy of accelerometer is improved.

Application for a patent for invention《The encapsulating structure and method for packing of MEMS chip》（Application number 201610046817.1）It is proposed MEMS chip is fixed in encapsulating structure with pin configuration, makes it vacantly inside encapsulating structure, is not contacted with package substrate, So as to the stress caused by thorough insulation package.

Patent of invention《MEMS inertial sensor encapsulating structure with stress isolation》、《The encapsulation of encapsulation stress can be reduced Construction》、《Chip is attached stress isolation》、《A kind of pressure sensor of the insulation package stress based on Si-Si bonding》、《It is a kind of MEMS device thermal stress isolation structure》、《A kind of MEMS device and preparation method thereof》Deng increased under existing MEMS bare chips Add one layer of special isolation structure and reduce influence of the encapsulation stress to chip deformation to realize, the shortcomings that this method be need it is extra Increase by a Rotating fields layer, therefore the gross thickness of device can be increased.Patent of invention《Encapsulated by back-patterned reduction MEMS chip The method of stress》Although employing etching technics has processed special graphic structure in chip back, chip and envelope are reduced The contact area of dress, but chip bottom remains the problem of multiple location is fixedly connected with shell, it is multipoint to be fixedly connected Thermal stress can be still produced, causes the deformation of chip.Patent of invention《The encapsulating structure and method for packing of MEMS chip》Using gold Belong to lead chip is suspended in package cavity body, be subsequently filled the retardance filler of electric insulation, finally sealed encapsulation cavity.It is lacked Point is that encapsulation cavity and retardance filler need specific customization, adds processed complex degree and cost.

The content of the invention

To solve problems of the prior art, this patent provides a kind of accurate floated MEMS chip envelope of central supported Assembling structure, it is characterized in that, the silicon substrate viscose glue of MEMS chip or bonding are fixed on ceramic cartridge cavity bottom surface, and silicon substrate is etched It is connected into only being supported by a central support structure with ceramic cartridge cavity.

The bottom electrode of MEMS chip is fixed on silica separation layer, and silica separation layer is fixed on a silicon substrate； The top electrode of MEMS chip is suspended in above bottom electrode by center anchor point structural support.

Silicon cap is bonded on the silicon electrode layer where top electrode, and top electrode and bottom electrode are sealed in MEMS capacitance sensors Cavity in.

The silicon substrate of the MEMS chip is fixed on pottery by central support structure and auxiliary support structure viscose glue or bonding Porcelain tube shell cavity bottom surface.

Central support structure and auxiliary support structure figure are set on the silicon substrate, utilize central support structure and auxiliary Supporting structure figure is helped to form the central support structure and auxiliary support structure of set depth as mask, etching, pass through center Supporting structure and auxiliary support structure viscose glue or bonding are fixed on ceramic cartridge cavity bottom surface.

Auxiliary support structure is circumferentially positioned at around central support structure.

Auxiliary support structure is centered on central support structure, and be centrosymmetric structural arrangement.

The area of central support structure figure is more than the area of auxiliary support structure figure.

Central support structure figure is round or polygon；

Auxiliary support structure figure is circle, polygon or the annular being circumferentially positioned at around central support structure figure.

After MEMS chip is fixed on ceramic cartridge cavity, etching removes auxiliary support structure, while member-retaining portion center branch Support structure is not etched, and makes silicon substrate be etched to only be connected with ceramic cartridge cavity by the support of portion centers supporting structure.

Ceramic cartridge is by kovar alloy cover plate for sealing.

The beneficial effect that the present invention is reached：

This patent is proposed by processing central support structure on a silicon substrate, and MEMS chip support approximation is suspended in envelope It in tubulature shell, can significantly reduce the encapsulation stress in MEMS chip, realize the low stress encapsulation of MEMS chip, increase without extra Add one layer of special stress isolation structure sheaf, therefore former package thickness can be kept constant.The structure is only needed to MEMS chip silicon Substrate is processed, formed central support structure, do not change MEMS chip inner sensor sensitive structure any structure design and Processing step, so not dramatically increasing the number of steps and complexity of MEMS chip, and is not required to special process material, With packaging technology it is simple, do not dramatically increase packaging cost, it is easy to accomplish the advantages of.

Brief description of the drawings

Fig. 1 is the encapsulation schematic diagram of common MEMS capacitive sensor.

Fig. 2（a）- Fig. 2（p）For a kind of processing technology step of the accurate floated MEMS chip encapsulating structure of central supported of the present invention Rapid schematic diagram.

Fig. 3（a）- Fig. 3（q）For another processing technology of the accurate floated MEMS chip encapsulating structure of central supported of the present invention Step schematic diagram.

Fig. 4（a）- Fig. 4（c）For the accurate floated MEMS chip encapsulating structure of central supported of the present invention central support structure and The micro Process plane mask layer schematic diagram of auxiliary support structure.

Embodiment

The invention will be further described below in conjunction with the accompanying drawings.Following embodiments are only used for clearly illustrating the present invention Technical solution, and be not intended to limit the protection scope of the present invention and limit the scope of the invention.

The ceramic package form that tradition becomes the MEMS capacitance sensors of space type is as shown in Figure 1.MEMS capacitance sensors Bottom electrode is directly anchored on silica separation layer, and silica separation layer is fixed on a silicon substrate.MEMS capacitance sensors Top electrode（That is MEMS sensitive structures mass block）Suspended on the bottom electrode by center anchor point structural support.Top electrode and lower electricity Extremely opposite to form capacitance, when there is extraneous sensitive amount input, the capacitor's capacity that top electrode is formed with bottom electrode changes, and leads to Cross the detection for the i.e. achievable sensitive amount to be measured of variable quantity for detecting the capacitance.

After MEMS chip substrate is fixed in ceramic cartridge by viscose glue or metal bonding mode, different materials it is hot swollen Swollen coefficient is different, and temperature change will produce thermal stress.Since bottom electrode is directly anchored on silica separation layer, lower electricity Pole deformation is larger.And top electrode is suspended on bottom electrode by a center anchor point structural support, and anchor point area is small, therefore Top electrode is heated stress influence very little.Therefore during temperature change, top electrode is inconsistent with the deformation of temperature with bottom electrode, causes to power on The capacitance that pole is formed with bottom electrode is affected by temperature, and the temperature characterisitic of sensor is poor.

The application by etched on the substrate of MEMS chip a larger central support structure of cross-sectional area and The less auxiliary support structure of several cross-sectional areas.Then by after MEMS chip scribing, viscose glue or bonding are fixed to ceramics In shell cavity, then carry out metal lead wire bonding.

Then the ceramic cartridge containing MEMS chip is integrally put into etching cavity, using isotropic etching gas（Example Such as gaseous state xenon difluoride）, isotropic etching is carried out to MEMS chip.Isotropic etching gas is with approximately uniform etching speed The silicon structure that rate etching exposes.By rationally designing following parameter：Planar dimension, the auxiliary support structure of central support structure Planar dimension, the height of supporting structure, isotropic etching technological parameter（Etch period, temperature, etching gas pressure etc.）, can Auxiliary support structure is not only etched to removal completely to realize, but also a part of central support structure can be retained and be not etched removal.

After the completion of isotropic etching, cavity is finally encapsulated using kovar alloy cover plate for sealing ceramic cartridge.

To avoid during the isotropic etching of substrate silicon, etching gas etch other silicon structures of chip, can be with Chip structure is protected using the methods of high-temperature oxydation chip surface, spraying photoresist, pre-buried silicon dioxide layer of protection.

Auxiliary support structure figure is circumferentially positioned at around central support structure figure, using central support structure figure as Center, be centrosymmetric structural arrangement.Central support structure graphics area is more than the area of auxiliary support structure figure.

It is preferred that the mask of central support structure can be the figure such as round, square.The mask of auxiliary support structure can Think by be necessarily distributed small circular, small rectangle, annular, the figure, such as Fig. 4 such as strip（a）- Fig. 4（c）It is shown.

Embodiment 1

Specific implementation step is as follows：

Step 1：MEMS capacitance sensors use standard SOI wafer piece, including silicon electrode layer 1,2 and of silica separation layer Silicon substrate 3, such as Fig. 2（a）It is shown.Anchor point is processed using dry or wet etch technique to the silicon electrode layer 1 of A wafers first Structure 11 and sensitive structure lower chamber 12, such as Fig. 2（b）It is shown.

Step 2：Processed using dry or wet etch technique on the silicon electrode layer of A wafers lower electrode arrangement 13, Bonded seal area 14 and scribe area 15, such as Fig. 2（c）It is shown.

Step 3：The silicon structural layer of another SOI wafer piece B is bonded to the bonded seal of A wafers using bonding technology Qu Shang, such as Fig. 2（d）It is shown.

Step 4：Using CMP（Chemical Mechanical Polishing）The silicon of wafer B is removed with etching technics Substrate and silica separation layer, such as Fig. 2（e）It is shown.

Step 5：Using deep etching technique, sensitive structure, such as Fig. 2 are processed on the silicon electrode layer of wafer B（f）Institute Show.

Step 6：Prepare silicon cap.TSV is used on monocrystalline silicon wafer crystal piece C first（Though Silicon Via）Technique adds Work goes out conductive through-silicon via structure, then using the upper and lower surface of photoresist protection silicon hole, then using wet method or dry process, adds Work goes out silicon cap cavity 21 and silicon cap separated region 22, such as Fig. 2（g）It is shown.

Step 7：Using bonding technology, silicon cap wafer C is bonded on the silicon electrode layer of wafer B, so that by sensitivity Sealing structure is in the cavity of MEMS chip, such as Fig. 2（h）It is shown.

Step 8：Using dry etch process or scribing process, remove the silicon cap separated region 22 of wafer C part or Whole monocrystalline silicon, the silicon cap of each chip are separated, such as Fig. 2（i）It is shown.

Step 9：Using the method for spraying photoresist, photoresist, such as Fig. 2 are sprayed in the positive and negative of wafer（j）It is shown.

Step 10：The photoresist etching above silicon cap silicon conductive through hole is removed, then splash-proofing sputtering metal, forms the weldering of chip Disk, such as Fig. 2（k）It is shown.

Step 11：Central support structure and auxiliary support structure figure are etched on the photoresist of chip silicon substrate bottom Shape, such as Fig. 2（l）It is shown.

Step 12：The central support structure that is processed by the use of in step 11 and auxiliary support structure photoetching offset plate figure are as covering Film, using anisotropic etch process, etches the central support structure and Auxiliary support knot for forming certain depth on a silicon substrate Structure, such as Fig. 2（m）It is shown.

Step 13：To wafer carry out scribing, the MEMS chip after scribing by being adhesively fixed in ceramic cartridge cavity, Then metal lead wire bonding, such as Fig. 2 are carried out（n）It is shown.

Step 14：Ceramic cartridge containing MEMS chip is integrally put into etching apparatus.Using isotropic etching gas The silicon that MEMS chip exposes is performed etching.Pass through rational design centre supporting structure and auxiliary support structure graphic scale The parameters such as very little, support structure height, isotropic etching technique, can not only etch removal auxiliary support structure completely, but also Member-retaining portion central support structure is not etched.The substrate sidewall silicon and lower electrode layer sidewall silicon exposed by scribing can be at the same time By isotropic etching gas etching, by reasonably increasing scribe area width, the substrate silicon that can increase scribe area lower part is wide Degree, to ensure that the silicon substrate of silicon cap lower part will not be etched by gas transverse.After the completion of etching, MEMS chip is only logical with ceramic cartridge Central support structure connection is crossed, MEMS chip realizes that approximation is suspended in ceramic cavity, such as Fig. 2（o）It is shown.

Step 15：Finally use kovar alloy cover plate for sealing ceramic cartridge.The quasi- suspension of central supported finally machined The MEMS sensor of formula such as Fig. 2（p）It is shown.

Embodiment 2

Specific implementation step is as follows：

Step 1：MEMS capacitance sensors use standard SOI wafer piece, including silicon electrode layer 1,2 and of silica separation layer Silicon substrate 3, such as Fig. 3（a）It is shown.Anchor point is processed using dry or wet etch technique to the silicon electrode layer 1 of A wafers first Structure 11 and sensitive structure lower chamber 12, such as Fig. 3（b）It is shown.

Step 2：Processed using dry or wet etch technique on the silicon electrode layer of A wafers lower electrode arrangement 13, Bonded seal area 14 and scribe area 15, such as Fig. 3（c）It is shown.

Step 3：The silicon electrode layer of another SOI wafer piece B is bonded to the bonded seal of A wafers using bonding technology Qu Shang, such as Fig. 3（d）It is shown.

Step 4：Using CMP（Chemical Mechanical Polishing）The silicon of wafer B is removed with etching technics Substrate and silica separation layer, such as Fig. 3（e）It is shown.

Step 5：Using deep etching technique, sensitive structure, such as Fig. 3 are processed on the silicon electrode layer of wafer B（f）Institute Show.

Step 6：Prepare silicon cap.TSV is used on monocrystalline silicon wafer crystal piece C first（Though Silicon Via）Technique adds Work goes out conductive through-silicon via structure, then using the upper and lower surface of photoresist protection silicon hole, then using wet method or dry process, adds Work goes out silicon cap cavity 21 and silicon cap separated region 22, such as Fig. 3（g）It is shown.

Step 7：Using bonding technology, silicon cap wafer C is bonded on the silicon electrode layer of wafer B, so that by sensitivity Sealing structure is in the cavity of MEMS chip, such as Fig. 3（h）It is shown.

Step 8：Using dry etch process or scribing process, remove the silicon cap separated region 22 of wafer C part or Whole monocrystalline silicon, the silicon cap of each chip are separated, such as Fig. 3（i）It is shown.

Step 9：Using the marginal position of scribe region of the deep etching technique on the silicon substrate of A wafers, etch Deep trouth, groove depth is up to middle silica separation layer, so that it is determined that going out the position of pre-buried silicon dioxide layer of protection, such as Fig. 3（j）Institute Show.

Step 10：The outer surface that chip exposes is aoxidized using high temperature oxidation process, is formed in chip outer surface Layer of silicon dioxide protective layer, such as Fig. 3（k）It is shown.

Step 10：Silicon dioxide layer of protection above the silicon conductive through hole of silicon cap is etched and is removed, then splash-proofing sputtering metal, shape Into the pad of chip, such as Fig. 3（l）It is shown.

Step 12：Etched on silicon dioxide layer of protection outside the silicon substrate of chip A wafers central support structure and Auxiliary support structure figure, such as Fig. 3（m）It is shown.

Step 13：The central support structure and Auxiliary support knot being had determined using step 12 on silicon dioxide layer of protection Composition shape, using anisotropic etch process, etches the central support structure for forming certain depth on a silicon substrate as mask And auxiliary support structure, such as Fig. 3（n）It is shown.

Step 14：Scribing is carried out to wafer, the MEMS chip after scribing is by being adhesively fixed to ceramic cartridge cavity bottom Face, then carries out metal lead wire bonding, such as Fig. 3（o）It is shown.

Step 15：Ceramic cartridge containing MEMS chip is integrally put into etching apparatus.Using isotropic etching gas MEMS chip is performed etching.Pass through rational design centre supporting structure and auxiliary support structure dimension of picture, supporting structure Highly, the parameter such as isotropic etching technique, can not only etch removal auxiliary support structure, but also member-retaining portion center completely Supporting structure is not etched.After the completion of etching, MEMS chip is only connected with ceramic cartridge by central support structure, MEMS chip Realize that approximation is suspended in ceramic cavity, such as Fig. 3（p）It is shown.

Step 16：Finally use kovar alloy cover plate for sealing ceramic cartridge.The quasi- suspension of central supported finally machined The MEMS sensor of formula such as Fig. 3（q）It is shown.

The above is only the preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art For member, without departing from the technical principles of the invention, some improvement and deformation can also be made, these are improved and deformation Also it should be regarded as protection scope of the present invention.

Claims (10)

1. a kind of accurate floated MEMS chip encapsulating structure of central supported, it is characterized in that, the silicon substrate viscose glue or key of MEMS chip Conjunction is fixed on ceramic cartridge cavity bottom surface, and silicon substrate is etched to only by central support structure support with ceramic cartridge cavity be connected Connect.

2. the accurate floated MEMS chip encapsulating structure of a kind of central supported according to claim 1, it is characterized in that, MEMS cores The bottom electrode of piece is fixed on silica separation layer, and silica separation layer is fixed on a silicon substrate；MEMS chip powers on Pole is suspended in above bottom electrode by center anchor point structural support.

3. the accurate floated MEMS chip encapsulating structure of a kind of central supported according to claim 2, it is characterized in that, silicon cap key Close on the silicon electrode layer where top electrode, top electrode and bottom electrode are sealed in the cavity of MEMS capacitance sensors.

4. the accurate floated MEMS chip encapsulating structure of a kind of central supported according to claim 1, it is characterized in that, it is described The silicon substrate of MEMS chip is fixed on ceramic cartridge cavity bottom by central support structure and auxiliary support structure viscose glue or bonding Face.

5. the accurate floated MEMS chip encapsulating structure of a kind of central supported according to claim 4, it is characterized in that, described Central support structure and auxiliary support structure figure are set on silicon substrate, utilize central support structure and auxiliary support structure figure As mask, etching forms the central support structure and auxiliary support structure of set depth, passes through central support structure and auxiliary Supporting structure viscose glue or bonding are fixed on ceramic cartridge cavity bottom surface.

6. the accurate floated MEMS chip encapsulating structure of a kind of central supported according to claim 4, it is characterized in that, auxiliary branch Support structure is circumferentially positioned at around central support structure.

7. the accurate floated MEMS chip encapsulating structure of a kind of central supported according to claim 4, it is characterized in that, auxiliary branch Support structure is centered on central support structure, and be centrosymmetric structural arrangement.

8. the accurate floated MEMS chip encapsulating structure of a kind of central supported according to claim 5, it is characterized in that, center branch The area of support structure figure is more than the area of auxiliary support structure figure.

9. the accurate floated MEMS chip encapsulating structure of a kind of central supported according to claim 5, it is characterized in that, center branch Support structure figure is round or polygon；

Auxiliary support structure figure is circle, polygon or the annular being circumferentially positioned at around central support structure figure.

10. the accurate floated MEMS chip encapsulating structure of a kind of central supported according to claim 4 or 5, it is characterized in that, After MEMS chip is fixed on ceramic cartridge cavity, etching removes auxiliary support structure, while member-retaining portion central support structure is not It is etched, makes silicon substrate be etched to only be connected with ceramic cartridge cavity by the support of portion centers supporting structure.