CN106404237A - Pressure sensor chip and preparation method, and absolute pressure sensor chip - Google Patents
Pressure sensor chip and preparation method, and absolute pressure sensor chip Download PDFInfo
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- CN106404237A CN106404237A CN201510456679.XA CN201510456679A CN106404237A CN 106404237 A CN106404237 A CN 106404237A CN 201510456679 A CN201510456679 A CN 201510456679A CN 106404237 A CN106404237 A CN 106404237A
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Abstract
The embodiment of the invention discloses a pressure sensor chip and a preparation method, and an absolute pressure sensor chip. The pressure sensor chip includes a glass base, a silicon pedestal and a silicon diaphragm which are arranged in turn. The upper surface of the silicon pedestal is provided with a first cavity and a second cavity, and a through cavity connecting the second cavity and the lower surface of the silicon pedestal is arranged below the second cavity. The inner ring of the through cavity is located in the periphery of the inner ring of the second cavity and the distance between the inner ring and the outer ring of the through cavity is smaller than the distance between the inner ring and the outer ring of the second cavity. The silicon diaphragm is fixed to the upper surface of the silicon pedestal. An absolute pressure varistor and a first Wheatstone bridge outputting an absolute pressure signal are arranged at the region edge, corresponding to the first cavity, of the surface of the silicon diaphragm. A differential pressure varistor and a second Wheatstone bridge outputting a differential pressure signal are arranged at the region edge, corresponding to the second cavity, of the surface of the silicon diaphragm. The glass base is provided with a vent hole communicating with the through cavity and the outside of the glass base. The application has a large measuring range and can realize the synchronous measurement of differential pressure and absolute pressure .
Description
Technical field
The present invention relates to microelectron-mechanical manufacture field, more particularly, to a kind of pressure sensor chip and preparation method.
Background technology
In fields such as Aeronautics and Astronautics, navigation, petrochemical industry, automobile makings, pressure transducer has a wide range of applications.
Pressure transducer belongs to microelectron-mechanical piezoresistive transducer, utilizes the pressure of monocrystal silicon by semiconductor packaging
The sensor chip that inhibition effect produces.Existing pressure sensor chip is divided into differential pressure pick-up chip and absolute pressure sensor
Chip, wherein, differential pressure pick-up chip is used for the difference between two pressure of measurement.Absolute pressure sensor chip is used for experiencing
Absolute pressure value is simultaneously exported by absolute pressure.If realizing the measurement to differential pressure and absolute pressure, one must be passed through
The mode of differential pressure pick-up chip and an absolute pressure sensor chip portfolio detection is realized one by one.
Additionally, existing wide range pressure sensor chip is when measuring slight pressure, and output signal is relatively low cannot meet detection
Require, and small-range pressure transducer disclosure satisfy that the detection requirement of slight pressure but cannot be applied to the measurement of high-pressure,
I.e. conventional pressure sensor chip has the little technological difficulties of measurement range always.
Content of the invention
The goal of the invention of the present invention is to provide a kind of pressure sensor chip, and it is capable of the synchronization inspection of differential pressure and absolute pressure
Survey, and there is larger measurement range, to solve the technical barrier existing for pressure sensor chip in prior art.
According to embodiments of the invention, there is provided a kind of pressure sensor chip, including the glass base setting gradually, silicon substrate
Seat and silicon diaphragm, wherein,
The upper surface of described silicon pedestal is provided with the first cavity, and the first cavity periphery, spacing first cavity are provided with annular
Second cavity, the lower section of the second cavity is communicated with the annular pass-through cavity of the second cavity and described silicon pedestal lower surface；Institute
The internal ring stating Through-cavity is located at the periphery of the second cavity internal ring, and the distance between described Through-cavity internal ring and outer shroud are little
In the distance between the second cavity internal ring and outer shroud；
Described silicon diaphragm is fixed on the upper surface of described silicon pedestal and covers the first cavity and the second cavity；
In the edges of regions of corresponding first cavity in described silicon diaphragm surface, it is provided with absolute pressure varistor and output absolute pressure signal
The first Wheatstone bridge；And, in the edges of regions of corresponding second cavity in described silicon diaphragm surface, it is provided with differential pressure pressure
Quick resistance and the second Wheatstone bridge of output differential pressure signal；
Described glass base is provided with and connects described Through-cavity and the passage outside described glass base.
Further, it is provided with the 3rd cavity between described Through-cavity and described passage, the 3rd cavity is from described glass
The upper surface concave downward of base, the aperture area of the 3rd cavity is more than the cross-sectional area of described Through-cavity outer shroud.
Preferably, the first cavity, the center superposition of the second cavity, described Through-cavity and the 3rd cavity.
It is further preferred that the center superposition of described glass base, described silicon pedestal and described silicon diaphragm, described silicon pedestal
The center superposition or parallel with the first cavity for the center.
Wherein, the described absolute pressure varistor in the first Wheatstone bridge is drawn by the first heavy doping contact area and the first metal
Line is by described absolute pressure signal output；
Described differential pressure varistor in second Wheatstone bridge passes through the second heavy doping contact area and the second metal lead wire will
Described differential pressure signal output.
According to a further aspect in the invention, there is provided prepare the preparation method of above-mentioned pressure sensor chip, including：
Using twin polishing silicon chip as silicon pedestal；
Make the first cavity and the second cavity in the upper surface of described silicon pedestal, wherein, the second cavity is surrounded on described first
The periphery of cavity distance the first cavity preseting length；
Prepare silicon dioxide layer on the surface of soi wafer；The device layer of soi wafer adopts n-type doping, SOI described in labelling
The face that silicon wafer devices layer is located is the lower surface of soi wafer；
The lower surface of described soi wafer is entered line unit with the upper surface of described silicon pedestal using the mode that high temperature hot melt is bonded
Close；First cavity and the second cavity are covered by described soi wafer, and the first cavity is formed with the lower surface of described soi wafer
Vacuum chamber；
The middle and upper part of described soi wafer is carried out thinning, until exposing the oxide layer in the middle of soi wafer；
The first Wheatstone bridge including absolute pressure varistor is made on the surface after described soi wafer is thinning and inclusion is poor
Second Wheatstone bridge of pressure varistor；
The annular pass-through cavity connecting with the second cavity in the lower surface making of described silicon pedestal, the internal ring of described Through-cavity
Positioned at the periphery of the second cavity internal ring, and the distance between described Through-cavity internal ring and outer shroud less than the second cavity internal ring with
The distance between outer shroud；Silicon pedestal in described Through-cavity forms silicon island；
The passage of preparation connection glass pedestal upper and lower surface in glass pedestal；Described passage is made to pass through with described
The connection of logical cavity, temperature be 350～400 DEG C, pressure be 500～1200N, voltage in the environment of 800～1200V to institute
State silicon pedestal and glass pedestal carries out anode linkage.
Further, after the passage of described preparation connection glass pedestal upper and lower surface in glass pedestal,
Before so that described passage is connected with described Through-cavity, also include：
HF acid is adopted to be corroded to prepare the 3rd cavity, the opening surface of the 3rd cavity in the upper surface of described glass pedestal
The long-pending cross-sectional area more than described Through-cavity outer shroud, the 3rd cavity is located between described Through-cavity and described passage.
Preferably, in the preparation method of described pressure sensor chip, including at least one in following technical scheme：
In the step that the described upper surface in silicon pedestal makes the first cavity and the second cavity：Using wet etching or dry
The mode of method etching makes the first cavity and the second cavity；
Prepare in the step of silicon dioxide layer on the described surface in soi wafer, prepare institute by the way of high-temperature thermal oxidation
State silicon dioxide layer；
Make in the step of the annular pass-through cavity connecting with the second cavity in the described lower surface in described silicon pedestal, adopt
The deep silicon etching technology of DRIE carries out deep etching, to form described Through-cavity；
In the step of the passage of described preparation connection glass pedestal upper and lower surface in glass pedestal, using sharp
The mode of light or sandblasting prepares described passage in described glass pedestal；
Make the first Wheatstone bridge including absolute pressure varistor in the upper surface of the described oxide layer in described soi wafer
Include with the step of the second Wheatstone bridge including differential pressure varistor：
Edge on surface after described soi wafer is thinning, above described first cavity and the second cavity passes through boron ion
The mode of injection synchronously prepares absolute pressure varistor, differential pressure varistor；Preparation absolute pressure varistor and differential pressure varistor
Continue the marginal position above described first cavity and the second cavity afterwards and prepare by way of second boron ion is injected
One heavy doping contact area and the second heavy doping contact area, synchronously activated by way of high annealing the impurity injecting twice from
Son, the long-pending metal of chemical wet etching fairlead, pad simultaneously completes graphical formation first metal lead wire of metal, the second metal lead wire
And fairlead.
In accordance with a further aspect of the present invention, additionally provide a kind of absolute pressure sensor chip, including the glass base setting gradually,
Silicon pedestal and silicon diaphragm, the upper surface of described silicon pedestal is provided with the first cavity, recessed in the first cavity periphery, spacing first
Chamber is provided with annular second cavity, and the lower section of the second cavity is communicated with the annular of the second cavity and described silicon pedestal lower surface
Through-cavity；The internal ring of described Through-cavity is located at the periphery of the second cavity internal ring, and described Through-cavity internal ring and outer shroud
The distance between less than the distance between the second cavity internal ring and outer shroud；
Described silicon diaphragm is fixed on the upper surface of described silicon pedestal and covers the first cavity and the second cavity；
In the edges of regions of corresponding first cavity in described silicon diaphragm surface, it is provided with the first absolute pressure varistor and output absolute pressure
First Wheatstone bridge of signal；And, in the edges of regions of corresponding second cavity in described silicon diaphragm surface, it is provided with the
Two varistors and the second Wheatstone bridge of output absolute pressure signal.
Further, the upper surface of described glass base has the 3rd cavity, and the aperture area of the 3rd cavity is more than described
The cross-sectional area of Through-cavity outer shroud.
From above technical scheme, the pressure sensor chip in the application can not only realize the synchronization of differential pressure and absolute pressure
Measurement, its range ability is significantly increased simultaneously.
Brief description
In order to be illustrated more clearly that the embodiment of the present invention or technical scheme of the prior art, below will be to required in embodiment
Accompanying drawing to be used be briefly described it should be apparent that, drawings in the following description be only the present invention some enforcement
Example, for those of ordinary skill in the art, on the premise of not paying creative work, can also be attached according to these
Figure obtains other accompanying drawings.
Fig. 1 is the front elevation according to a pressure sensor chip being preferable to carry out exemplifying；
Fig. 2 be Fig. 1 in A-B to sectional view；
Fig. 3 (a) -3 (j) is the main processes section according to a pressure sensor chip being preferable to carry out exemplifying
Schematic diagram；
Fig. 4 is the center section plan according to an absolute pressure sensor chip being preferable to carry out exemplifying.
Specific embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete
Description it is clear that described embodiment is only a part of embodiment of the present invention, rather than whole embodiment.Base
Embodiment in the present invention, it is all that those of ordinary skill in the art are obtained under the premise of not making creative work
Other embodiment, broadly falls into the scope of protection of the invention.
It is unable to the defect of synchro measure in order to solve differential pressure and absolute pressure in prior art, differential pressure is sensed by present inventor
Chip internal structure, in a pressure sensor chip, is optimized by device chip and absolute pressure sensor integrated chip simultaneously,
Increase the range ability of pressure sensor chip, so that the pressure sensor chip in the application and conventional pressure sensor core
Piece is compared, and pressure limit is wide, anti-overload ability strong, realize the features such as differential pressure and absolute pressure synchronous detecting to have measurement.
Below the structure and working principle of the pressure sensor chip in the application is described in detail.
Fig. 1 is the front elevation according to a pressure sensor chip being preferable to carry out exemplifying.Fig. 2 be Fig. 1 in A-B to
Sectional view.
As depicted in figs. 1 and 2, pressure sensor chip includes glass base 1, silicon pedestal 2 and the silicon fiml setting gradually
Piece 3.Preferably, the center superposition of glass base 1, silicon pedestal 2 and silicon diaphragm 3.
The upper surface of silicon pedestal 2 is provided with the first cavity 4.First cavity 4 periphery, spacing the first cavity 4 are provided with annular
Second cavity 5.In the present embodiment, including but not limited to circular rings or the regular polygon ring of the second cavity 5.Second cavity 5
Lower section be communicated with the annular pass-through cavity 6 of the second cavity 5 and silicon pedestal 2 lower surface.The internal ring of Through-cavity 6 is located at the
The periphery of two cavity 5 internal ring, and the distance between Through-cavity 6 internal ring and outer shroud are less than between the second cavity 5 internal ring and outer shroud
Distance.Silicon pedestal 2 in the middle of second cavity 5 and the silicon pedestal 2 in the middle of Through-cavity 6 constitute silicon island 13.Preferably, originally
The shape of the Through-cavity 6 in embodiment includes but is not limited to circular rings or regular polygon ring.As the preferred reality in each embodiment
Apply example, in the application, the shape of the second cavity 5 is identical with the shape of Through-cavity 6, i.e. the ring generally circular in shape of the second cavity 5
When, the shape of Through-cavity 6 is also circular rings；When being shaped as regular polygon ring of second cavity 5, the shape of Through-cavity 6
Also it is regular polygon ring.
As the preferred embodiment in each embodiment, the center superposition of the first cavity 4, the second cavity 5 and Through-cavity 6,
The center of one cavity 4 and the center superposition or parallel of silicon pedestal 2.
Silicon diaphragm 3 is fixed on the upper surface of silicon pedestal 2 and covers the first cavity 4 and the second cavity 5.The upper surface of silicon diaphragm 3
It is respectively provided with silicon dioxide layer 14 with lower surface.In this application, silicon diaphragm 3 and silicon pedestal 2 can be bonded by high temperature hot melt
Mode is bonded and then is achieved a fixed connection.When silicon diaphragm 3 is fixed on the upper surface of silicon pedestal 2, the first cavity 4 and its
On silicon diaphragm 3 constitute vacuum chamber.Now, the silicon diaphragm of vacuum chamber overlying regions is the first strain films 30, the second cavity 5 area
Silicon diaphragm above domain is the second strain films 31.
At the edge of the first strain films 30, that is, the edges of regions of corresponding first cavity 4 in silicon diaphragm 3 surface, is provided with absolute pressure pressure
Quick resistance Ra1, Ra2, Ra3 and Ra4, the first heavy doping contact area 7 and the first metal lead wire 8.Absolute pressure varistor Ra1,
Ra2, Ra3 and Ra4 constitute the first Wheatstone bridge.Absolute pressure varistor in first Wheatstone bridge is connect by the first heavy doping
Tactile area 7 and the first metal lead wire 8 are by absolute pressure signal output.
At the edge of the second strain films 31, that is, the edges of regions of corresponding second cavity 5 in silicon diaphragm 3 surface, is provided with differential pressure pressure
Quick resistance Rd1, Rd2, Rd3 and Rd4, the second heavy doping contact area 9 and the second metal lead wire 10.Differential pressure varistor Rd1,
Rd2, Rd3 and Rd4 constitute the second Wheatstone bridge.Differential pressure varistor in second Wheatstone bridge is connect by the second heavy doping
Differential pressure signal is exported by tactile area 9 and the second metal lead wire 10.
Glass base 1 is provided with connection Through-cavity 6 and the passage 11 outside glass base 1.
Below the operation principle of the pressure sensor chip in above-described embodiment is described in detail.
As shown in Fig. 2 the first cavity 4 in chip, the first strain films 30, the first Wheatstone bridge, the first heavy doping contact
Area 7 and the first metal lead wire 8 decomposition pressure sensor I, i.e. absolute pressure sensor.The second cavity 5 in chip, Through-cavity 6,
Passage 11, the second strain films 31, the second Wheatstone bridge, the second heavy doping contact area 9 and the second metal lead wire 10 form
Pressure transducer II, i.e. differential pressure pick-up.
For pressure transducer I, vacuum chamber is formed by the first strain films 30 and the first cavity 4 sealing.When the first strain films
When 30 upper end has pressure, the first strain films 30 can produce flexural deformation, and the stress that flexural deformation produces is by the pressure-sensitive electricity of absolute pressure
Resistance Ra1, Ra2, Ra3 and Ra4 and the first Wheatstone bridge being made up of above-mentioned varistor are converted into voltage signal output.
Because the lower end of the first strain films 30 is vacuum zero pressure, therefore pressure transducer I can realize the measurement of absolute pressure.
For pressure transducer II, the lower end of the second strain films 31 is passed through in the second cavity, Through-cavity 6 and glass base 1
Passage 11 achieve connection with external environment, when the region that the upper end of the second strain films 31 is connected with passage 11 exists
During pressure differential, the second strain films 31 can produce in the presence of pressure differential and be badly deformed, and the stress that deformation produces is by the pressure-sensitive electricity of differential pressure
Hinder Rd1, Rd2, Rd3 and Rd4 and be converted into voltage signal output by the second Wheatstone bridge that above-mentioned differential pressure varistor is constituted,
Therefore pressure transducer II can realize the measurement of differential pressure.
By the combination of pressure transducer I and pressure transducer II, the pressure sensor chip in the application can realize absolute pressure
Synchro measure with differential pressure.
When applying pressure in the upper surface of the second strain films 31, the second strain films 31 are bent downwardly deformation, glass pedestal
There is provided for silicon island and support the partial pressure that can offset on the second strain films 31.If the top of Through-cavity 6 is not provided with the second cavity
5, then the second strain films 31 contact with the opening of Through-cavity 6, due to the opening of Through-cavity 6 and connecing of the second strain films 31
Contacting surface is long-pending less, when the pressure on the second strain films 31 is gradually increased, the limited pressure that the second strain films 31 bear, and work as pressure
When power exceedes certain limit, the second strain films 31 then can rupture.Pressure sensor chip therefore in the application is in Through-cavity 6
Top arrange the second cavity 5, the distance between Through-cavity 6 internal ring and outer shroud be less than between the second cavity 5 internal ring and outer shroud
Distance, that is, the lifting surface area of the second cavity 5 be more than and run through the lifting surface area of cavity.Due to considerably increasing the second strain films 31
Contact area, pressure limit that the second strain films 31 bear increases, and the second strain films 31 will not rupture easily.Simultaneously second
The lifting surface area of cavity 5 is more than the lifting surface area running through cavity, thus the second strain films 31 have larger deformation space, therefore its
The range of differential pressure pick-up greatly increases.
It should be noted that in the application the distance between Through-cavity 6 internal ring and outer shroud and the second cavity 5 internal ring and outer shroud it
Between distance difference bigger, the range ability of differential pressure pick-up is bigger.In the application, for proportionate relationship between the two
It is not specifically limited, those skilled in the art can determine both proportionate relationships according to the range ability needing in actual production process.
It should be noted that when the wide range differential pressure pick-up normal work in chip, the first strain films 30 of absolute pressure sensor
The pressure being born has been much larger than the working range of wide range differential pressure pick-up, and that is, small-range absolute pressure sensor chip needs to bear
High overload pressure.For avoid small-range absolute pressure sensor lost efficacy it is ensured that in the application pressure sensor chip wide range model
Enclose, the application is it is further preferred that be provided with the 3rd cavity 12 between Through-cavity 6 and passage 11.3rd cavity 12 is certainly
The upper surface concave downward of glass base 1, the aperture area of the 3rd cavity 12 is more than the cross-sectional area of Through-cavity 6 outer shroud.Make
For preferred version, the center superposition of the center of the 3rd cavity 12 and the first cavity 4, the second cavity 5 and Through-cavity 6, with silicon
The center superposition of pedestal 2 or parallel.
In the upper surface of glass base 1, the 3rd cavity 12 is set, when the pressure bearing on the first strain films 30 constantly increases,
First strain films 30 are bent downwardly deformation, and the silicon island of the first strain films 30 lower section is gradually to the 3rd cavity in glass pedestal
12 is close.Because the 3rd cavity 12 makes the first strain films 30 have larger deformation space, therefore the range of absolute pressure sensor is big
Big increase.The depth of the 3rd cavity 12 determines the range ability of the first strain films 30.For the 3rd cavity 12 in the application
Depth is not specifically limited, and those skilled in the art can determine the 3rd cavity 12 according to the range ability needing in actual production process
Depth.After silicon island is contacted with the bottom of the 3rd cavity 12, glass pedestal provides for silicon island and supports and offset the first strain films 30
On partial pressure, thus the first strain films 30 can also be reduced (be far longer than the first strain films normal work model in overload pressure
The pressure enclosing is referred to as overload pressure) the lower probability that fracture occurs of effect.
From above technical scheme, the pressure sensor chip in the application can not only realize the synchronization of differential pressure and absolute pressure
Measurement, its range ability is significantly increased simultaneously.
According to a further aspect in the invention, additionally provide a kind of preparation method preparing above-mentioned pressure sensor chip. Fig. 3 (a)-
3 (b) is the main processes generalized section according to a pressure sensor chip being preferable to carry out exemplifying.
In Fig. 3 (a), using twin polishing silicon chip as silicon pedestal 2.
In Fig. 3 (b), make the first cavity 4 in the upper surface of silicon pedestal 2 using the mode of wet etching or dry etching
With the second cavity 5.Wherein, the second cavity 5 is surrounded on periphery distance the first cavity 4 preseting length of the first cavity 4.
Carry out soi wafer for piece in Fig. 3 (c).From device layer for n-type doping soi wafer as standby piece, and in SOI
Silicon dioxide layer 14 is prepared on the surface of silicon chip by the way of high-temperature thermal oxidation, and device layer (corresponding biography in labelling soi wafer
The silicon diaphragm 3 of sensor) face that is located is the lower surface of soi wafer.
In Fig. 3 (d), the lower surface of soi wafer is entered line unit with the upper surface of silicon pedestal 2 using the mode that high temperature hot melt is bonded
Close.First cavity 4 and the second cavity 5 are covered by soi wafer, and the first cavity 4 forms vacuum chamber with the lower surface of soi wafer.
In Fig. 3 (e), the middle and upper part of soi wafer is carried out thinning, until exposing the oxide layer in soi wafer.
In Fig. 3 (f), the surface after soi wafer is thinning makes the first Wheatstone bridge and the bag including absolute pressure varistor
Include the second Wheatstone bridge of differential pressure varistor.
Specifically, the surface after soi wafer is thinning makes and include the first Wheatstone bridge of absolute pressure varistor and include：
Edge on surface after described soi wafer is thinning, above the first cavity 4 and the second cavity 5 passes through boron ion
The mode of injection synchronously prepares absolute pressure varistor, differential pressure varistor.Preparation absolute pressure varistor and differential pressure varistor
Continue the marginal position above the first cavity and the second cavity afterwards and prepare the first weight by way of second boron ion is injected
Doping contact area 7 and the second heavy doping contact area 9, synchronously activated by way of high annealing the impurity injecting twice from
Son, chemical wet etching fairlead, the long-pending metal of pad and complete graphical formation first metal lead wire 8 of metal, the second metal draws
Line 10 and fairlead.
In Fig. 3 (g), the deep silicon etching technology adopting DRIE in the lower surface of silicon pedestal 2 carries out deep etching to make and second
The annular pass-through cavity 6 of cavity 5 connection, the internal ring of Through-cavity 6 is located at the periphery of the second cavity 5 internal ring, and Through-cavity 6
The distance between internal ring and outer shroud are less than the distance between the second cavity 5 internal ring and outer shroud；Silicon pedestal 2 shape in Through-cavity 6
Become silicon island.
In Fig. 3 (h), HF acid is adopted to be corroded to prepare the 3rd cavity 12, the 3rd cavity 12 in the upper surface of glass pedestal
Aperture area be more than Through-cavity 6 outer shroud cross-sectional area；
In Fig. 3 (i), connection glass pedestal upper and lower surface is prepared by the way of laser or sandblasting on glass pedestal
Passage 11；Passage 11 is made to connect with the 3rd cavity 12.
In Fig. 3 (j), temperature be 350～400 DEG C, pressure be 500～1200N, voltage be 800～1200V in the environment of
Silicon pedestal 2 and glass pedestal are carried out anode linkage.
In accordance with a further aspect of the present invention, additionally provide a kind of absolute pressure sensor chip of wide range.Fig. 4 is according to a preferred reality
Apply the center section plan of the absolute pressure sensor chip exemplifying.As shown in figure 4, absolute pressure sensor chip include setting gradually and in
Glass base 1, silicon pedestal 2 and silicon diaphragm 3 that the heart overlaps.The upper surface of silicon pedestal 2 is provided with the first cavity 4, recessed first
Chamber 4 periphery, spacing the first cavity 4 are provided with annular second cavity 5, and the lower section of the second cavity 5 is communicated with the second cavity 5
Annular pass-through cavity 6 with silicon pedestal 2 lower surface.The internal ring of Through-cavity 6 is located at the periphery of the second cavity 5 internal ring, and institute
State the distance between Through-cavity 6 internal ring and outer shroud less than the distance between the second cavity 5 internal ring and outer shroud.In second cavity 5
Between silicon pedestal 2 and the silicon pedestal 2 in the middle of Through-cavity 6 constitute silicon island 13.
Preferably, the shape of the Through-cavity 6 in the present embodiment includes but is not limited to circular rings or regular polygon ring.As each reality
Apply the preferred embodiment in example, in the application, the shape of the second cavity 5 is identical with the shape of Through-cavity 6, i.e. the second cavity 5
Ring generally circular in shape when, the shape of Through-cavity 6 is also circular rings；When being shaped as regular polygon ring of second cavity 5, passes through
The shape of logical cavity 6 is also regular polygon ring.As the preferred embodiment in each embodiment, the first cavity 4, the second cavity 5
With the center superposition of Through-cavity 6, the center of the first cavity 4 and the center superposition or parallel of silicon pedestal 2.
Further, the upper surface of glass base 1 has the 3rd cavity 12, and the aperture area of the 3rd cavity 12 is more than insertion sky
The cross-sectional area of chamber 6 outer shroud.
Silicon diaphragm 3 is fixed on the upper surface of silicon pedestal 2 and covers the first cavity 4 and the second cavity 5, is covered in the first cavity 4
Form the first vacuum chamber, the second cavity 5, Through-cavity 6 and the 3rd cavity 12 constitute the second vacuum chamber.Above first vacuum chamber
Silicon diaphragm 3 be the first strain films 30, the silicon diaphragm 3 above the second vacuum chamber be the second strain films 31.
In the edges of regions of the first vacuum chamber, that is, the edges of regions of corresponding first cavity 4 in silicon diaphragm 3 surface, is provided with first exhausted
Pressure varistor Ra1, Ra2, Ra3 and Ra4, the first heavy doping contact area 7 and the first metal lead wire 8.Absolute pressure varistor
Ra1, Ra2, Ra3 and Ra4 constitute the first Wheatstone bridge.Absolute pressure varistor in first Wheatstone bridge passes through the first weight
Doping contact area 7 and the first metal lead wire 8 are by absolute pressure signal output.In the edges of regions of the second vacuum chamber, that is, in silicon diaphragm 3
The edges of regions of corresponding second cavity 5 in surface, is provided with second varistor Rd1, Rd2, Rd3 and Rd4, the second heavy doping
Contact area 9 and the second metal lead wire 10.Absolute pressure varistor Rd1, Rd2, Rd3 and Rd4 constitute the second Wheatstone bridge.The
Absolute pressure varistor in two Wheatstone bridges passes through the second heavy doping contact area 9 and the second metal lead wire 10 will be defeated for absolute pressure signal
Go out.
Wherein, the first vacuum chamber, the first strain films and the first Wheatstone bridge constitute wide range absolute pressure sensor I, the second vacuum
Chamber, the second strain films and the second Wheatstone bridge constitute small-range absolute pressure sensor II.Compare the pressure sensor chip in Fig. 1
Structure, the glass base 1 in the present embodiment is not provided with passage.Second cavity 5, Through-cavity 6 and the 3rd cavity 12 are constituted
Vacuum sealing.The first strain films 30 above wide range absolute pressure sensor I and second above small-range absolute pressure sensor II should
Become film 31 to there is identical thickness but there are different areas of section, due to the second strain above small-range absolute pressure sensor II
The area of section of film is bigger, and therefore when carrying out pressure measxurement, the deflection of the second strain films is big, and transducer sensitivity is high, therefore the
Two strain films are applicable to make the less absolute pressure sensor of range.The sectional area of the first strain films is less, in uniform pressure effect
Lower first strain films deflection is little, and transducer sensitivity is low, therefore the first strain films are applicable to make range less absolute pressure sensing
Device.By the combination of above-mentioned two absolute pressure sensor can at double expansion absolute pressure sensor chip measurement range.
Therefore the absolute pressure sensor chip in above-described embodiment can measure the absolute pressure of small-range scope, machine with wide range also can be measured
Absolute pressure, compared with single small-range absolute pressure sensor and wide range absolute pressure sensor, its range significantly expands its range ability,
The scope of application is wider.
It is described above and precision architecture illustrated in the accompanying drawings it should be appreciated that the invention is not limited in, and
Various modifications and changes can carried out without departing from the scope.The scope of the present invention only to be limited by appended claim.
Claims (10)
1. a kind of pressure sensor chip, including the glass base (1) setting gradually, silicon pedestal (2) and silicon diaphragm (3), its feature
It is,
The upper surface of described silicon pedestal (2) is provided with the first cavity (4), sets in the first cavity (4) periphery, spacing first cavity (4)
It is equipped with annular second cavity (5), the lower section of the second cavity (5) is communicated with the second cavity (5) and described silicon pedestal (2) lower surface
Annular pass-through cavity (6)；The internal ring of described Through-cavity (6) is located at the periphery of the second cavity (5) internal ring, and described Through-cavity (6)
The distance between internal ring and outer shroud are less than the distance between the second cavity (5) internal ring and outer shroud；
Described silicon diaphragm (3) is fixed on the upper surface of described silicon pedestal (2) and is covered the first cavity (4) and the second cavity (5)；
In the edges of regions of corresponding first cavity (4) in described silicon diaphragm (3) surface, it is provided with absolute pressure varistor and output absolute pressure letter
Number the first Wheatstone bridge；And, in the edges of regions of corresponding second cavity (5) in described silicon diaphragm (3) surface, it is provided with difference
Pressure varistor and the second Wheatstone bridge of output differential pressure signal；
Described glass base (1) is provided with and connects described Through-cavity (6) passage (11) outside with described glass base (1).
2. pressure sensor chip according to claim 1 is it is characterised in that in described Through-cavity (6) and described ventilation
It is provided with the 3rd cavity (12), from the upper surface concave downward of described glass base (1), the 3rd is recessed for the 3rd cavity (12) between hole (11)
The aperture area in chamber (12) is more than the cross-sectional area of described Through-cavity (6) outer shroud.
3. pressure sensor chip according to claim 1 and 2 it is characterised in that the first cavity (4), the second cavity (5),
Described Through-cavity (6) and the center superposition of the 3rd cavity (12).
4. pressure sensor chip according to claim 3 is it is characterised in that described glass base (1), described silicon pedestal
(2) and described silicon diaphragm (3) center superposition, center center superposition or parallel with the first cavity (4) of described silicon pedestal (2).
5. pressure sensor chip according to claim 4 is it is characterised in that described absolute pressure in the first Wheatstone bridge
Varistor passes through the first heavy doping contact area (7) and the first metal lead wire (8) by described absolute pressure signal output；
Described differential pressure varistor in second Wheatstone bridge passes through the second heavy doping contact area (9) and the second metal lead wire (10)
Described differential pressure signal is exported.
6. a kind of preparation method of pressure sensor chip is it is characterised in that include：
Using twin polishing silicon chip as silicon pedestal (2)；
Make the first cavity (4) and the second cavity (5) in the upper surface of described silicon pedestal (2), wherein, the second cavity (5) is surrounded on
The periphery of described first cavity (4) distance first cavity (4) preseting length；
Prepare silicon dioxide layer on the surface of soi wafer；The device layer of soi wafer adopts n-type doping, SOI silicon described in labelling
The face that piece device layer is located is the lower surface of soi wafer；
The lower surface of described soi wafer is bonded using the mode that high temperature hot melt is bonded with the upper surface of described silicon pedestal (2)；
First cavity (4) and the second cavity (5) are covered by described soi wafer, and the first cavity (4) is formed with the lower surface of described soi wafer
Vacuum chamber；
The middle and upper part of described soi wafer is carried out thinning, until exposing the oxide layer in the middle of soi wafer；
The first Wheatstone bridge including absolute pressure varistor is made on the surface after described soi wafer is thinning and includes differential pressure pressure
Second Wheatstone bridge of quick resistance；
The annular pass-through cavity (6) connecting with the second cavity (5) in the lower surface making of described silicon pedestal (2), described Through-cavity (6)
Internal ring be located at the periphery of the second cavity (5) internal ring, and the distance between described Through-cavity (6) internal ring and outer shroud to be less than second recessed
The distance between chamber (5) internal ring and outer shroud；Silicon pedestal (2) in described Through-cavity (6) forms silicon island；
The passage (11) of preparation connection glass pedestal upper and lower surface in glass pedestal；Make described passage (11) and institute
State Through-cavity (6) connection, temperature be 350～400 DEG C, pressure be 500～1200N, voltage is the environment of 800～1200V
Under anode linkage is carried out to described silicon pedestal (2) and glass pedestal.
7. preparation method according to claim 6 is it is characterised in that prepare connection glass base described in glass pedestal
After the passage (11) of seat upper and lower surface, before so that described passage (11) is connected with described Through-cavity (6), also wrap
Include：
HF acid is adopted to be corroded to prepare the 3rd cavity (12), the opening of the 3rd cavity (12) in the upper surface of described glass pedestal
Area is more than the cross-sectional area of described Through-cavity (6) outer shroud, and the 3rd cavity (12) is located at described Through-cavity (6) and described ventilation
Between hole (11).
8. preparation method according to claim 6 is it is characterised in that include at least one in following technical scheme：
In the step that the described upper surface in silicon pedestal (2) makes the first cavity (4) and the second cavity (5)：Using wet etching or
The mode of person's dry etching makes the first cavity (4) and the second cavity (5)；
Prepare in the step of silicon dioxide layer on the described surface in soi wafer, prepare described two by the way of high-temperature thermal oxidation
Silicon oxide layer；
Make in the step of the annular pass-through cavity (6) connecting with the second cavity (5) in the described lower surface in described silicon pedestal (2),
Deep silicon etching technology using DRIE carries out deep etching, to form described Through-cavity (6)；
In the step of the passage (11) of described preparation connection glass pedestal upper and lower surface in glass pedestal, using sharp
The mode of light or sandblasting prepares described passage (11) in described glass pedestal；
Described described thinning after soi wafer surface on make and include the first Wheatstone bridge and the inclusion of absolute pressure varistor
The step of the second Wheatstone bridge of differential pressure varistor includes：
Edge on surface after described soi wafer is thinning, above described first cavity and the second cavity is injected by boron ion
Mode synchronously prepare absolute pressure varistor, differential pressure varistor；Prepare described absolute pressure varistor and differential pressure varistor is follow-up
Continue the marginal position above described first cavity and the second cavity and prepare the first heavy doping by way of second boron ion is injected
Contact area (7) and the second heavy doping contact area (9), synchronously activate the foreign ion injecting twice, light by way of high annealing
Carve etch lead hole, pad the graphical formation first metal lead wire (8) amassed metal and complete metal, the second metal lead wire (10) and draw
String holes.
9. a kind of absolute pressure sensor chip, including the glass base (1) setting gradually, silicon pedestal (2) and silicon diaphragm (3), its feature
It is, the upper surface of described silicon pedestal (2) is provided with the first cavity (4), in the first cavity (4) periphery, spacing first cavity (4)
It is provided with annular second cavity (5), the lower section of the second cavity (5) is communicated with the second cavity (5) and described silicon pedestal (2) lower surface
Annular pass-through cavity (6)；The internal ring of described Through-cavity (6) is located at the periphery of the second cavity (5) internal ring, and described Through-cavity
(6) the distance between internal ring and outer shroud are less than the distance between the second cavity (5) internal ring and outer shroud；
Described silicon diaphragm (3) is fixed on the upper surface of described silicon pedestal (2) and is covered the first cavity (4) and the second cavity (5)；
In the edges of regions of corresponding first cavity (4) in described silicon diaphragm (3) surface, it is provided with the first absolute pressure varistor and output is exhausted
First Wheatstone bridge of pressure signal；And, in the edges of regions of corresponding second cavity (5) in described silicon diaphragm (3) surface, setting
There are the second varistor and the second Wheatstone bridge of output absolute pressure signal.
10. absolute pressure sensor chip according to claim 9 is it is characterised in that the upper surface of described glass base (1) is opened
There is the 3rd cavity (12), the aperture area of the 3rd cavity (12) is more than the cross-sectional area of described Through-cavity (6) outer shroud.
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| CN107478378A (en) * | 2017-09-26 | 2017-12-15 | 航天南洋（浙江）科技有限公司 | A kind of small two-way signal output pressure sensor structure |
| CN107941407A (en) * | 2017-11-19 | 2018-04-20 | 东北大学 | A kind of micro-voltage high-overload sensor chip |
| CN108332898A (en) * | 2018-04-17 | 2018-07-27 | 南京信息工程大学 | A kind of compound range baroceptor and high-precision sounding air pressure measuring apparatus |
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| CN111166335A (en) * | 2019-12-31 | 2020-05-19 | 深圳大学 | Absolute pressure sensor assembly and air bag type respiration measuring device |
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