CN207254707U - Ultrasonic transducer and ultrasonic fingerprint sensor - Google Patents
Ultrasonic transducer and ultrasonic fingerprint sensor Download PDFInfo
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- CN207254707U CN207254707U CN201720396599.4U CN201720396599U CN207254707U CN 207254707 U CN207254707 U CN 207254707U CN 201720396599 U CN201720396599 U CN 201720396599U CN 207254707 U CN207254707 U CN 207254707U
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Abstract
This application discloses ultrasonic transducer and ultrasonic fingerprint sensor.The ultrasonic transducer is used to produce ultrasonic wave according to drive signal and produces detection signal according to echo, it is characterised in that including：Mask layer, the mask layer covering and surrounding cavity, and including extending to the opening of the cavity from surface；And the laminated piezoelectric on the mask layer.The ultrasonic transducer forms cavity using sacrificial patterned, so as to reduce manufacture cost and improve the performance of sensor.
Description
Technical field
Fingerprint sensor is the utility model is related to, more particularly, to ultrasonic transducer and ultrasonic fingerprint sensor.
Background technology
Living things feature recognition is the technology for distinguishing different biological features, including fingerprint, palmmprint, face, DNA, sound
Etc. identification technology.Fingerprint refers to the convex uneven lines of the positive surface skin fovea superior of the finger tips of people, the regular arrangement form of lines
Different line types.Fingerprint recognition refers to by the details of more different fingerprints to carry out identity authentication.Due to lifelong
Consistency, uniqueness and convenience, the application of fingerprint recognition are more and more extensive.
In fingerprint recognition, information in fingerprint is obtained using sensor.According to the difference of operation principle, fingerprint sensor
Optics, capacitance, pressure, sonac can be divided into.Optical sensor volume is larger, and price is relatively high, and for fingerprint
Drying or dampness it is sensitive, belong to first generation fingerprint identification technology.Optical fingerprint identification system cannot be penetrated due to light
Skin surface, so can only be by scanning the surface of finger skin, it is impossible to be deep into skin corium.In this case, finger is dry
The effect of net degree direct influence identification, if having glued more dust, sweat etc. in user's finger, may just occur identification
The situation of error.Also, touched if people do a fingerprint hand according to finger, it is also possible to pass through identifying system.Therefore, for
For family, optical sensor using for the use of there is safety and stability the problem of.Capacitive fingerprint sensor technology uses
Array of capacitors detects the lines of fingerprint, belongs to second generation fingerprint sensor.Each capacitor includes two pole plates.Touched in finger
When touching, the lines of fingerprint forms a dielectric part between pole plate, so as to detect fingerprint according to the change of capacitance
Lines.Capacitive fingerprint sensing device is lower and compact than optics sensor price, and stability is high, makes in actual product
Use more attractive.For example, the fingerprint sensor used in many mobile phones is capacitive fingerprint sensing device.However, capacitance
Formula fingerprint sensor has the shortcomings that can not evading, i.e., is had a great influence be subject to temperature, humidity, contamination.
As a further improvement, third generation fingerprint sensor has been developed, wherein the inverse piezoelectricity using piezoelectric
Effect produces ultrasonic wave.The ultrasonic wave shows different reflectivity and transmission when touching fingerprint in the ridge, valley in fingerprint
Rate.Finger print information can be read by the ultrasonic beam signal scanned in certain area.Ultrasonic fingerprint sensor produces super
Sound wave can be scanned so as to penetrating the phone housing made of glass, aluminium, stainless steel, sapphire or plastics, so that will
Ultrasonic fingerprint sensor is arranged in phone housing.The advantage is Customer design a new generation gracefulness, innovation, the movement of differentiation
Terminal provides flexibility.In addition, the experience of user also gets a promotion, scanning fingerprint can be from there may be contamination on finger
Influence, such as sweat, hand lotion etc., so as to improve the stability and accuracy of fingerprint sensor.
Existing ultrasonic fingerprint sensor includes the ultrasonic transducer and cmos circuit integrated.Eutectic bonding
It is the effective ways of integrated CMOS circuit and ultrasonic transducer, but this kind of method alignment precision is low, manufacture is of high cost.More
Economic scheme is directly to manufacture ultrasonic transducer on cmos circuit surface, is set between cmos circuit and ultrasonic transducer
Insulating layer is put to separate the two.Cmos circuit in the structure is used to handle ultrasonic signal, therefore ultrasonic fingerprint sensor can
To read and identify fingerprint at a high speed.However, ultrasonic transducer includes the cavity structure below laminated piezoelectric, the cavity knot
Structure not only manufactures difficulty, and due to process deviation cause the frequency of ultrasonic fingerprint sensor is unstable, parameter consistency is poor,
And yield rate is poor.
Utility model content
In view of this, the purpose of this utility model is to provide ultrasonic transducer and ultrasonic fingerprint sensor, wherein, profit
Cavity is formed with sacrificial patterned, with the performance for reducing manufacture cost and improving sensor.
One side according to the present utility model, there is provided a kind of method for manufacturing ultrasonic fingerprint sensor, including：Formed
Cmos circuit；And ultrasonic transducer is formed on the cmos circuit, the cmos circuit and the ultrasonic transducer
Connection, for driving the ultrasonic transducer and handling the detection signal of the ultrasonic transducer generation, wherein, formed super
The step of acoustic wave transducer, includes：Form sacrifice layer；Sacrificial patterned；Mask layer is formed on the sacrifice layer, it is described to cover
Mold layer covers and around the sacrifice layer；The opening for reaching the sacrifice layer is formed on the mask layer；Via the opening
Vapor phase etchant is carried out, so that removing the sacrifice layer forms cavity；And form laminated piezoelectric on the mask layer.
Preferably, before sacrifice layer is formed, further include：The first insulating layer is formed on the cmos circuit.
Preferably, before sacrifice layer is formed, further include：Passivation layer is formed on the cmos circuit.
Preferably, after the formation of the cavity, further include：Sealant is formed on the mask layer to close the opening.
Preferably, after the formation of the cavity, further include：The second insulating layer is formed on the mask layer.
Preferably, second insulating layer closes the opening.
Preferably, etch-back is carried out to second insulating layer with reduce thickness.
Preferably, the step of forming laminated piezoelectric includes：Piezoelectric layer is formed on second insulating layer；And form institute
State being electrically connected between piezoelectric layer and the cmos circuit.
Preferably, the step of forming cmos circuit includes：At least one transistor is formed on substrate；And it is described extremely
Multiple wiring layers and multiple interlayer dielectric layers are formed on a few transistor, wherein, the multiple wiring layer is by the multiple layer
Between dielectric layer be separated into multiple and different aspects.
Preferably, formed between the piezoelectric layer and the cmos circuit includes the step of electrical connection：Described in formation
Before piezoelectric layer, first electrode is formed on second insulating layer；After the piezoelectric layer is formed, on the piezoelectric layer
Form second electrode；And formed and extended to respectively from the first electrode and the second electrode in the multiple wiring layer
The first contact and the second contact of at least one wiring layer, wherein, the first electrode and the second electrode contact institute respectively
State the lower surface and upper surface of piezoelectric layer.
Preferably, first contact reaches first electricity from the upper surface of the piezoelectric layer through the piezoelectric layer
Pole.
Preferably, the step of forming first contact and the described second contact includes：After the piezoelectric layer is formed,
Form the first through hole and the second through hole that at least one wiring layer is reached from the piezoelectric layer upper surface；It is logical described first
The 3rd insulating layer is formed on the side wall of hole and second through hole；Conductive layer is formed in the piezoelectric layer surface so that described to lead
Electric layer fills the first through hole and second through hole；And the conductive layer pattern is formed into first contact and institute
State the second contact.
Preferably, the second electrode is formed by the conductive layer pattern, and is contacted and be connected to each other with described second.
Preferably, the step of forming first contact and the described second contact includes：Before the piezoelectric layer is formed,
Form the first through hole that at least one wiring layer is reached from the second insulating layer upper surface；In the side of the first through hole
The 3rd insulating layer is formed on wall；The first conductive layer is formed on second insulating layer so that first conductive layer fills institute
State first through hole；And first conductive layer pattern chemical conversion described first is contacted；After the piezoelectric layer is formed, formed
The second through hole of at least one wiring layer is reached from the piezoelectric layer upper surface；Formed on the side wall of second through hole
4th insulating layer；The second conductive layer is formed on the piezoelectric layer so that second conductive layer fills second through hole；With
And second conductive layer pattern chemical conversion described second is contacted.
Preferably, the first electrode is formed by first conductive layer pattern, and is contacted each other with described first
Connection, the second electrode is formed by second conductive layer pattern, and is contacted and be connected to each other with described second.
Preferably, the cmos circuit includes at least one transistor, formed the piezoelectric layer and the cmos circuit it
Between electrical connection the step of include：The piezoelectric layer is via the first electrode, the second electrode, first contact, institute
State the second contact and at least one wiring layer is connected at least one transistor.
Preferably, between form second insulating layer the step of and the step of forming the piezoelectric layer, further include：
Seed Layer is formed on second insulating layer.
Preferably, the piezoelectric layer and the Seed Layer respectively by selected from aluminium nitride, segregation vinyl fluoride, segregation vinyl fluoride-
Any one composition in trifluoro-ethylene, lead titanate piezoelectric ceramics, lithium niobate piezoelectric ceramics.
Preferably, substantially 0.1 micron to 0.8 micron of the lateral dimension of the opening.
Preferably, the sacrifice layer is made of the material selected from germanium or silicon.
Preferably, the etching gas used in the vapor phase etchant is XeF2。
Preferably, the sacrifice layer is made of germanium, and the chemical reaction in the vapor phase etchant is：Ge+2*XeF2=2*Xe+
GeF4。
Preferably, the mask layer is made of corrosion resistant material.
Preferably, the corrosion resistant material includes any one in silica, silicon nitride, carborundum, gold, copper.
Another aspect according to the present utility model, there is provided a kind of ultrasonic transducer is super for being produced according to drive signal
Sound wave and according to echo produce detection signal, including：Mask layer, mask layer covering and surrounding cavity, and including from
Surface extends to the opening of the cavity；And the laminated piezoelectric on the mask layer.
Preferably, further include：The first insulating layer below the sacrifice layer.
Preferably, further include：Sealant on the mask layer, the sealant close the opening.
Preferably, the second insulating layer on the mask layer is further included.
Preferably, second insulating layer closes the opening.
Preferably, the laminated piezoelectric includes：Piezoelectric layer on second insulating layer；And respectively described in contact
The lower surface of piezoelectric layer and the first electrode of upper surface and second electrode.
Preferably, further include：Seed Layer between second insulating layer and the piezoelectric layer.
Preferably, the piezoelectric layer and the Seed Layer respectively by selected from aluminium nitride, segregation vinyl fluoride, segregation vinyl fluoride-
Any one composition in trifluoro-ethylene, lead titanate piezoelectric ceramics, lithium niobate piezoelectric ceramics.
Preferably, substantially 0.1 micron to 0.8 micron of the lateral dimension of the opening.
Preferably, the sacrifice layer is made of the material selected from germanium or silicon.
Preferably, the mask layer is made of corrosion resistant material.
Preferably, the corrosion resistant material includes any one in silica, silicon nitride, carborundum, gold, copper.
Preferably, further include：Connected with the first electrode and provide the first of external connection and contacted；And with described
Two electrodes connect and provide the second contact of external connection.
Preferably, first contact reaches first electricity from the upper surface of the piezoelectric layer through the piezoelectric layer
Pole.
Preferably, the first electrode contacts with described first and is formed by identical conductive layer patternization and be connected to each other.
Preferably, the second electrode contacts with described second and is formed by identical conductive layer patternization and be connected to each other.
Another aspect according to the present utility model, there is provided a kind of ultrasonic fingerprint sensor, including：Cmos circuit；And
Above-mentioned at least one ultrasonic transducer, wherein, the cmos circuit is connected with the ultrasonic transducer, for driving
State at least one ultrasonic transducer and handle the detection signal that at least one ultrasonic transducer produces.
Preferably, the cmos circuit includes substrate and at least one transistor formed on substrate.
Preferably, the cmos circuit further includes multiple wiring layers at least one transistor and multiple layers
Between dielectric layer, the multiple wiring layer is separated into multiple and different aspects by the multiple interlayer dielectric layer.
Preferably, the piezoelectric layer is via the first electrode, the second electrode, first contact, described second
Contact and at least one wiring layer are connected at least one transistor.
Preferably, at least one ultrasonic transducer further includes：Described in being reached from the piezoelectric layer upper surface at least
The first through hole and the second through hole of one wiring layer；And on the side wall of the first through hole and second through hole
Three insulating layers, wherein, first contact and the described second contact are prolonged via the first through hole and second through hole respectively
Extend at least one wiring layer.
Preferably, at least one ultrasonic transducer further includes：Described in being reached from the piezoelectric layer lower surface at least
The first through hole of one wiring layer；The second through hole of at least one wiring layer is reached from the piezoelectric layer upper surface；It is located at
The 3rd insulating layer on the side wall of the first through hole, the 4th insulating layer on the side wall of second through hole, wherein, institute
State the first contact and it is described second contact extended to respectively via the first through hole and second through hole it is described at least one
Wiring layer.
Preferably, further include：Passivation layer on the cmos circuit.
Preferably, at least one ultrasonic transducer forms array.
According to the ultrasonic fingerprint sensor of the utility model embodiment, ultrasonic transducer is stacked on cmos circuit,
Different tube cores is thus connected without eutectic bonding, thus reduces manufacture cost and improves yield rate.In this method
In, cavity is formed using sacrificial patterned, can not only reduce the difficulty of cavity formation, but also can more accurately be limited
The size of cavity.
In a preferred embodiment, sacrifice layer and mask layer are sequentially formed, then, use vapor phase etchant remove sacrifice layer with
Form cavity.The pattern of sacrifice layer is used for the positions and dimensions for limiting cavity, so as to accurately control the horizontal ruler of cavity
Very little and longitudinal size.This method can provide structural support above cavity, for further making piezoelectric layer.With wet etching
Compare, which avoids the submergence of solution, has dry method, the two-fold advantage of wet processing concurrently.Vapor phase etchant can be with
Avoid moisture or etch products from residuing in cavity, further improve the acoustical behavior of ultrasonic transducer.
In a further preferred embodiment, sacrifice layer is made of germanium or silicon, the etching gas used in vapor phase etchant
For XeF2.Etch products are Xe and GeF4, both at gaseous state, easily discharged from cavity, it is residual so as to reduce etch products
Stay.
In a further preferred embodiment, sacrifice layer is formed on the first insulating layer, the material of the two is different so that opens
Mouth can penetrate sacrifice layer and stop at the top of the first insulating layer.Therefore, can be accurate by controlling the thickness of sacrifice layer
Ground controls the longitudinal size of cavity.In sacrificial patterned, mask can be utilized to accurately control the lateral dimension of cavity.Should
The material of first insulating layer can select any material different from sacrifice layer corrosion resistance, such as spin-coating glass, so as to subtract
Small stress, avoids adverse effect of the unnecessary stress to the piezoelectric layer subsequently formed, maintains the parameter of ultrasonic fingerprint sensor
Uniformity.
The features such as ultrasonic fingerprint transducer sensitivity of this method manufacture is high, it is small to be affected by the external environment, high speed, at the same time
Manufacture cost is significantly reduced again and improves processing compatibility.
Brief description of the drawings
By the description to the utility model embodiment referring to the drawings, above-mentioned and other mesh of the utility model
, feature and advantage will be apparent from, in the accompanying drawings：
Fig. 1 shows the flow chart of the ultrasonic fingerprint sensor manufacturing process according to the utility model first embodiment；
Fig. 2 shows to form the flow chart of ultrasonic transducer in the method shown in Fig. 1；
Fig. 3 a-3j show each rank in the ultrasonic fingerprint sensor manufacturing process according to the utility model first embodiment
The schematic sectional view of section；
Fig. 4 shows the schematic cross-section of the ultrasonic fingerprint sensor according to the utility model second embodiment；
Fig. 5 shows the schematic cross-section of the ultrasonic fingerprint sensor according to the utility model 3rd embodiment；
Fig. 6 shows the schematic cross-section of the ultrasonic fingerprint sensor according to the utility model fourth embodiment；
Fig. 7 shows the schematic cross-section of the ultrasonic fingerprint sensor according to the 5th embodiment of the utility model；
Fig. 8 shows the operation principle schematic diagram of ultrasonic fingerprint sensor.
Embodiment
Hereinafter reference will be made to the drawings is more fully described the utility model.In various figures, identical element is using similar
Reference numeral represent.For the sake of clarity, the various pieces in attached drawing are not necessarily to scale.Furthermore, it is possible to it is not shown
Some known parts.
It describe hereinafter many specific details of the utility model, such as the structure of device, material, size, place
Science and engineering skill and technology, to be more clearly understood that the utility model.But just as the skilled person will understand,
The utility model can not be realized according to these specific details.
The utility model can be presented in a variety of manners, some of them example explained below.
Fig. 1 shows the flow chart of the ultrasonic fingerprint sensor manufacturing process according to the utility model first embodiment.Should
Method includes forming the cmos circuit and ultrasonic transducer of stacking, the active area of cmos circuit and the piezoelectricity of ultrasonic transducer
It is spaced apart between lamination using insulating layer.
In step slo, the cmos circuit for signal processing circuit is formed on substrate.The cmos circuit is included at least
One transistor, multiple wiring layers and multiple interlayer dielectric layers.The transistor include the source region that is formed in the substrate and drain region,
The gate-dielectric and grid conductor formed on substrate.The multiple wiring layer is separated into more by the multiple interlayer dielectric layer
A different aspect.For example, the first wiring layer in the multiple wiring layer is used for source region and the drain region for connecting the transistor
At least one, the second wiring layer is used to connect ultrasonic transducer.First wiring layer and the second wiring layer are situated between via through interlayer
The conductive channel of matter layer is connected to each other.
In step S20, ultrasonic transducer is formed on cmos circuit.The ultrasonic transducer includes using sacrifice layer
The cavity formed with mask layer, and the laminated piezoelectric formed on mask layer.Laminated piezoelectric is for example including piezoelectric layer and position
In first electrode and second electrode on its apparent surface.The active area of cmos circuit and the laminated piezoelectric of ultrasonic transducer it
Between be spaced apart using insulating layer.
The ultrasonic fingerprint sensor is for example further included to be led to from reach at least one wiring layer from piezoelectric layer respectively first
Hole and the second through hole, and the first contact extended at least partially in first through hole and at least a portion are in the second through hole
Second contact of extension.The first electrode and second electrode of ultrasonic transducer respectively via first contact and second contact and
Transistor in cmos circuit is connected.
In the method, the cmos circuit and ultrasonic transducer of stacking are formed in same tube core, because without adopting
Different tube cores is connected with eutectic bonding, thus reduces manufacture cost and improves yield rate.In same tube core, CMOS
Circuit is electrically connected to each other with ultrasonic transducer, which is used to drive the ultrasonic transducer and handles the ultrasound
The detection signal that wave transducer produces, thus reading speed can be improved.
Fig. 2 shows to form the flow chart of ultrasonic transducer in the method shown in Fig. 1.The step shown in Fig. 1 is described below
Each step in rapid S20.
In the step s 21, sacrifice layer is formed；
In step S22, sacrificial patterned.
In step S23, mask layer is formed on the sacrifice layer, the mask layer covers and around the sacrifice layer.
In step s 24, the opening for reaching the sacrifice layer is formed on the mask layer.
In step s 25, vapor phase etchant is carried out via the opening, so that removing the sacrifice layer forms cavity.It is described
Stop-layer and the mask layer surround the cavity together.
In step S26, laminated piezoelectric is formed on the mask layer.Laminated piezoelectric for example including piezoelectric layer and is located at
First electrode and second electrode on its apparent surface.
In the method, sacrifice layer and mask layer are sequentially formed, then, uses vapor phase etchant to remove sacrifice layer to form sky
Chamber.The pattern of sacrifice layer is used for the positions and dimensions for limiting cavity, so as to accurately control the lateral dimension of cavity and indulge
To size.This method can provide structural support above cavity, for further making piezoelectric layer.Compared with wet etching,
Vapor phase etchant technique avoids the submergence of solution, has dry method, the two-fold advantage of wet processing concurrently.Vapor phase etchant can be to avoid moisture
Or etch products are residued in cavity, further improve the acoustical behavior of ultrasonic transducer.The ultrasonic wave of this method manufacture refers to
The features such as line transducer sensitivity is high, it is small to be affected by the external environment, high speed, while significantly reduce manufacture cost again and improve technique
Compatibility.
Fig. 3 a-3j show each stage in the ultrasonic fingerprint sensor manufacturing process according to the utility model embodiment
Schematic sectional view.Each step shown in Fig. 1 and 2 is described in detail below in conjunction with Fig. 3 a-3j.
In step slo, the cmos circuit 110 for signal processing circuit is formed.Show in fig. 3 a the step it
Schematic structure afterwards.
The step forms the cmos circuit 110 for signal processing circuit.The cmos circuit is for example including at least a portion
Form multiple transistors in the substrate 101, and the first interlayer dielectric layer stacked gradually above the multiple transistor
106th, the first wiring layer 107, the second interlayer dielectric layer 108 and the second wiring layer 109.As an example, shown only in Fig. 3 a
One P-type transistor and only one N-type transistor.N-type well region 102 is formed in P type substrate 101.Then, in N-type well region
The source/drain region 103 of P-type transistor is formed in 102.Source/area 104 of N-type transistor is formed in P type substrate 101.Served as a contrast in p-type
The gate-dielectric 111 and grid conductor 105 stacked gradually is formed on bottom 101 and N-type well region 102.In P-type transistor, grid
Separated between pole conductor 105 and N-type well region 102 by gate-dielectric 111, grid conductor 105 is horizontal between adjacent source/drain region
To extension so that N-type well region 102 is located at a part for the lower section of grid conductor 105 as channel region.In N-type transistor, grid
Separated between conductor 105 and P type substrate 101 by gate-dielectric 111, grid conductor 105 is horizontal between adjacent source/drain region
Extension so that P type substrate 101 is located at a part for the lower section of grid conductor 105 as channel region.The source/drain region of P-type transistor
103 and the source/drain region 104 of N-type transistor and grid conductor 105 can be via conductive channel and the first wiring layer 107 and
Any one electrical connection in two wiring layers 109.
In alternate embodiments, the transistor in cmos circuit 110 is not limited to two, but can include at least one
Transistor, the interlayer dielectric layer in cmos circuit 110 can include at least one interlayer dielectric layer not only in two,
Wiring layer in cmos circuit 110 is not limited to two, but can include at least one wiring layer.
Technique for forming cmos circuit 110 is known, and this will not be detailed here.
In step S20, ultrasonic transducer 120 is formed on cmos circuit 110.Step is shown in Fig. 3 b-3j
The more detailed step of S20.
In the step s 21, insulating layer 121 and sacrifice layer 122 are sequentially formed on interlayer dielectric layer 108.The insulating layer 121
Such as by being formed selected from any material of silica, silicon nitride, for example with plasma enhanced chemical vapor deposition (PE-
CVD) formed.Sacrifice layer 122 is for example made of germanium or silicon.It is for instance possible to use evaporation forms germanium layer, as sacrifice layer 122.It is sacrificial
E.g., about 0.2 micron to 5 microns of the thickness of domestic animal layer 122.The insulating layer 121 is optional layer, if 108 phase of interlayer dielectric layer
There is required corrosion resistance for sacrifice layer 122, then can save insulating layer 121.
In step S22, using including gluing, exposed and developed photoetching process, photoresist mask is formed.Via photoetching
Glue mask is etched, and sacrifice layer 122 is patterned, as shown in Figure 3b.The etching for example can be using the wet of etching solution
Method etch process, or the dry method etch technology carried out in the reactor chamber, such as plasma etching.After the etching, lead to
Cross to dissolve or be ashed in a solvent and remove photoresist mask.
In step S23, such as by deposition, mask layer 123 is formed on sacrifice layer 122, as shown in Figure 3c.Mask layer
123 are made of corrosion resistant material, such as are made of any one in silica, silicon nitride, carborundum, gold, copper.Mask layer
123 thickness is, for example, 0.5 micron to 10 microns.Mask layer 123 covers and around sacrifice layer 122.Formed mask layer 123 it
Afterwards, chemical-mechanical planarization (CMP) can be carried out with the surface of smooth mask layer 123.
In step s 24, using above-mentioned photoetching process and etch process, mask layer 123 is patterned to comprising opening
151 mask pattern.Substantially 0.1 micron to 0.8 micron of the lateral dimension of opening 151.The opening 151 is using as etchant
Into passage and the passing away of etch products.
In step s 25, sacrifice layer 122 is further etched via the opening 151 of mask layer 123, as shown in Figure 3d.Utilize
The selectivity of etchant so that the surface for being etched in mask layer 123 and insulating layer 121 stops, so as to remove sacrifice layer
122, cavity 152 is formed in mask layer 123.Opening 151 communicates with each other with cavity 152.
Preferably, cavity 152 is formed using different etch process patterned mask layers 123 and in insulating layer 121.
For example, using wet etching process in patterned mask layer 123, vapor phase etchant technique is used when forming cavity 152.It is preferred that
Ground, sacrifice layer 122 are made of germanium, and mask layer 123 is made of silica, then the etchant used when forming cavity 152 is gas
Body XeF2。
Chemical reaction in the vapor phase etchant is：Ge+2*XeF2=2*Xe+GeF4.Etch products are Xe and GeF4, the two
It is gaseous state, is easily discharged from cavity.
In this step, the pattern of sacrifice layer 122 is used for the positions and dimensions for limiting cavity, so as to pass through sacrifice layer
122 patterning, accurately controls the lateral dimension and longitudinal size of cavity 152.
Even if opening 151 is small-sized, etchant can also reach sacrifice layer 122, etch products via opening 151
It can be discharged via opening 151.Therefore, 151 size of being open there is no and be limited be subject to etch process.Due to each to same
The etching characteristic of property, can form large-sized cavity 152 via opening 151.
In step S26, the step shown in Fig. 3 e to 3j is further performed, laminated piezoelectric is formed on mask layer 123.
As shown in Figure 3 e, such as by deposition, insulating layer 126 is formed on mask layer 123.Insulating layer 126 is for example by selecting
A kind of composition in autoxidation silicon and silicon nitride.Preferably, insulating layer 126 is made of silica, is increased for example with plasma
Extensive chemical vapour deposition (PE-CVD) formation.Insulating layer 126 is located at the top of mask layer 123, closes the opening in mask layer 123
151 so that cavity 152 is also closing.In a kind of alternative embodiment, if there is Seed Layer, then Seed Layer can be made
For insulating layer.In another alternative embodiment, additional sealant can be used to replace the closing opening of insulating layer 126.Should
Sealant can be made of any materials, such as non-crystalline silicon or metal.
Preferably, according to the size of the deposition characteristics of insulating layer 126 selection opening 151 so that insulating layer 126 is in opening
151 top can continuously extend.In this embodiment, 151 diameter of being open is about 0.1 micron to 0.8 micron so that insulation
Layer 126 can close opening 151, and the inside of non-entry cavity 152.Select to insulate according to the acoustic characteristic of ultrasonic transducer
The thickness of layer 126.In this embodiment, the thickness of insulating layer 126 is, for example, 0.2 micron to 2 microns.If insulating layer 126
Thickness is excessive, then can carry out etch-back after deposition with reduce thickness.
Further, as illustrated in figure 3f, such as by deposition, first electrode 132 and pressure are sequentially formed on insulating layer 126
Electric layer 133.Technique for forming piezoelectric layer 133 is, for example, reactive sputter-deposition, for forming the technique example of first electrode 132
Conventional ion sputters in this way.First electrode 132 is for example made of Mo, and thickness is about 0.2 micron to 1 micron.Piezoelectric layer 133 is for example
It is made of aluminium nitride, thickness is about 0.5 micron to 2 microns.
Preferably, before first electrode 132 is formed, such as by deposition, Seed Layer 131 is formed on insulating layer 126.
Technique for forming Seed Layer 131 is, for example, reactive sputtering.Seed Layer 131 is for example made of aluminium nitride, and thickness is about 0.1 micro-
Rice is to 0.5 micron.
In alternate embodiments, piezoelectric layer 133 and Seed Layer 131 are respectively by selected from aluminium nitride, segregation vinyl fluoride
(PVDF), segregation vinyl fluoride-trifluoro-ethylene (PVDF-TrFE), lead zirconate titanate (PZT) piezoelectric ceramics, lithium niobate (LiNbO3) pressure
Any one composition in electroceramics.
Further, as shown in figure 3g, using above-mentioned photoetching process and etch process, formed and reach the second wiring layer
109 through hole 153153.The through hole 153153 sequentially pass through from top to bottom piezoelectric layer 133, first electrode 132, Seed Layer 131,
Insulating layer 126, mask layer 123 and insulating layer 121.Utilize the selectivity of etchant so that be etched in the table of the second wiring layer 109
Face stops.
Further, as illustrated in figure 3h, such as by deposition, the shape in the surface of piezoelectric layer 133 and through hole 153153
Into conformal insulating layer 134, then, the surface of piezoelectric layer 133 is located at using anisotropic dry etching removal insulating layer 134
Part, and positioned at the part of the bottom of through hole 153153.So that insulating layer 134 covers the inner wall of through hole 153153, and
The surface of piezoelectric layer 133 near through hole 153153 extends laterally a part.The insulating layer 134 is used as lining so that through hole
Isolate between the middle conductive channel by formation and piezoelectric layer 133 and first electrode 132.
Further, as shown in figure 3i, the second electrode 135 with the upper surface of piezoelectric layer 133 is formed, and is passed through
Piezoelectric layer reaches the first contact 136 of first electrode 132, and contacts 137 with the second of the connection of second electrode 135.First connects
Touch 136 and second contact 137 be spaced apart.The step can use same conductive layer to form second electrode 135, first and contact
136 and second contact 137.For example, using above-mentioned photoetching process and etch process, formation penetrates piezoelectric layer and reaches first electrode
132 through hole.Then, the conductive layer of filling through hole is formed by depositing conductive material, which is not only filled with through piezoelectricity
The through hole of layer 133, and the through hole 153 that cmos circuit is reached from piezoelectric layer is filled at least in part.Using above-mentioned photoetching
Technique and etch process, by the contact 136 of conductive layer pattern chemical conversion second electrode 135, first and the second contact 137.Second electrode
135th, the first contact 136 and the second contact 137 are made of any conductor material, for example, the metal selected from one of Au, Ag and Al.
Alternatively, the step of patterned conductive layer can use and peel off (Lift-off) technique, wherein, forming conductive layer
Before, photoresist mask is formed using photoetching process, after conductive layer is formed, removes and lead while photoresist mask is removed
The part of electric layer, so that by conductive layer pattern.
First contact 136 is connected to the first electrode positioned at the lower section of piezoelectric layer 133 via the through hole through piezoelectric layer 133
132, and it is connected to the second wiring layer 109 via the through hole 153153 being previously formed.Second contact 137 is connected to second electrode
135, and it is connected to the second wiring layer 109 via the through hole 153153 being previously formed.Further, the second wiring layer 109 can
First wiring layer 107 is connected to via conductive channel with connection, and then is connected to the active area of cmos circuit 110.In the implementation
In example, the conductive material in through hole 153153 forms conductive channel.Therefore, piezoelectric layer 133 in ultrasonic transducer
Two apparent surfaces, are utilized respectively the first contact 136 and second and contact 137 CMOS being connected to below ultrasonic transducer
Circuit 110.
Further, as shown in Fig. 3 j, such as by deposition, passivation layer 138 is formed to cover second electrode 135, first
The contact of contact 136, second 137 and piezoelectric layer 133, so as to complete ultrasonic fingerprint sensor 100.
In the method for the embodiment, vapor phase etchant sacrifice layer is used to form cavity, can not only be reduced cavity and be formed
Difficulty, and can more it is accurate exactly limit cavity size.Further, this method can provide knot above cavity
Structure supports, for further making piezoelectric layer.Compared with wet etching, which avoids the submergence of solution, simultaneous
Have dry method, the two-fold advantage of wet processing.Vapor phase etchant can be residued in cavity to avoid moisture or etch products, further changed
The acoustical behavior of kind ultrasonic transducer.The ultrasonic fingerprint transducer sensitivity height of this method manufacture, be affected by the external environment
The features such as small, high speed, while manufacture cost is significantly reduced again.In a preferred embodiment, using gas XeF2As etchant,
So as to reduce etch products residual.
Further, the shape and size of finally formed cavity are determined according to the design parameter of ultrasonic transducer.It is logical
The thickness of control sacrifice layer is crossed, the longitudinal size of cavity can be accurately controlled.In sacrificial patterned, mask can be utilized
Accurately control the lateral dimension of cavity.The material of mask layer and the first insulating layer can select different from sacrifice layer corrosion resistance
Any material, such as spin-coating glass, so as to reduce stress, and avoid unnecessary stress to the piezoelectric layer that subsequently forms
Adverse effect, maintains the parameter consistency of ultrasonic fingerprint sensor.
Fig. 4 shows the schematic cross-section of the ultrasonic fingerprint sensor 100 according to the utility model second embodiment.This is super
Sound wave fingerprint sensor 100 is formed for example with above-mentioned manufacture method according to first embodiment.The ultrasonic fingerprint sensor
100 include the cmos circuit 110 and ultrasonic transducer 120 of stacking.
The cmos circuit 110 includes the multiple transistors of at least a portion formation in the substrate 101, and the multiple
The multiple wiring layers and multiple interlayer dielectric layers stacked gradually above transistor.As an example, show only one P in Fig. 4
Transistor npn npn and only one N-type transistor, the first interlayer dielectric layer 106, the first wiring layer 107, the second interlayer dielectric layer 108
With the second wiring layer 109.N-type well region 102 is formed in P type substrate 101.Then, P-type transistor is formed in N-type well region 102
Source/drain region 103.Source/area 104 of N-type transistor is formed in P type substrate 101.In P type substrate 101 and N-type well region 102
Form the gate-dielectric 111 and grid conductor 105 stacked gradually.In P-type transistor, grid conductor 105 and N-type well region
Separated between 102 by gate-dielectric 111, grid conductor 105 extends laterally between adjacent source/drain region so that N-type well region
102 part below grid conductor 105 is as channel region.In N-type transistor, grid conductor 105 and P type substrate
Separated between 101 by gate-dielectric 111, grid conductor 105 extends laterally between adjacent source/drain region so that P type substrate
101 part below grid conductor 105 is as channel region.The source/drain region 103 of P-type transistor and N-type transistor
Source/drain region 104 and grid conductor 105 can be via appointing in conductive channel and the first wiring layer 107 and the second wiring layer 109
One electrical connection.
The ultrasonic transducer 120 includes insulating layer 121, mask layer 123 and insulation on the cmos circuit 110
Layer 126, and the laminated piezoelectric on mask layer 123.The covering of mask layer 123 and surrounding cavity 152.Mask layer 123
Including opening 151, which is used to provide producing into passage and etching for etchant in the forming process of cavity 152
The passing away of thing.In a preferred embodiment, be open 151 substantially 0.1 micron to 0.8 micron of lateral dimension.Insulating layer
126 on cavity 152.The closing of insulating layer 126 opening 151, and the laminated piezoelectric to subsequently form provide mechanical support work
With.
The laminated piezoelectric of the ultrasonic transducer 120 includes the Seed Layer 131, first electrode 132, piezoelectric layer stacked gradually
133 and second electrode 135.In an alternative embodiment, if forming Seed Layer 131,131 envelope of Seed Layer can be used
The opening 151 in mask layer 123 is closed, so as to save insulating layer 126., can be in mask layer in another alternative embodiment
Additional sealant is formed on 123 to close the opening 151 in mask layer 123, insulating layer 126 is then formed, so as to carry
The intensity of high mechanical support.
Further, ultrasonic fingerprint sensor 100, which further includes, is used for cmos circuit 110 and ultrasonic transducer 120
The first contact 136 being electrically connected to each other and the second contact 137.Same conductive layer can be used to form second electrode 135, first
136 and second contact 137 of contact.First contact 136 is connected under piezoelectric layer 133 via the through hole through piezoelectric layer 133
The first electrode 132 of side, and it is connected to the second wiring via the through hole 153153 of the second wiring layer 109 of arrival of piezoelectric layer 133
Layer 109.Second contact 137 is connected to second electrode 135, and the through hole of the second wiring layer 109 is reached via piezoelectric layer 133
153153 are connected to the second wiring layer 109.The side wall of the through hole 153153 could be formed with insulating layer 134 and be used as lining so that
First contact 136 and the second contact 137 and the remainder of laminated piezoelectric are dielectrically separated from.Further, the second wiring layer 109 can
First wiring layer 107 is connected to via conductive channel with connection, and then is connected to the active area of cmos circuit 110.In the implementation
In example, the conductive material in through hole 153153 forms conductive channel.Therefore, piezoelectric layer 133 in ultrasonic transducer
Two apparent surfaces, are utilized respectively the first contact 136 and second and contact 137 CMOS being connected to below ultrasonic transducer
Circuit 110.
In this embodiment, ultrasonic fingerprint sensor 100 is included in the ultrasonic transducer stacked on cmos circuit 110
120, it is spaced apart by insulating layer 121 therebetween.Therefore, which connects without eutectic bonding
Different tube cores is connect, thus reduces manufacture cost and improves yield rate.In ultrasonic transducer 120, patterning is utilized
Sacrifice layer forms cavity, can not only reduce the difficulty of cavity formation, but also can more accurately limit the size of cavity.
Fig. 5 shows the schematic cross-section of the ultrasonic fingerprint sensor 200 according to the utility model 3rd embodiment.This is super
Sound wave fingerprint sensor 200 includes the cmos circuit 110 and ultrasonic transducer 220 stacked.
Cmos circuit 110 in ultrasonic fingerprint sensor 200 according to third embodiment with it is according to second embodiment
Cmos circuit 110 in ultrasonic fingerprint sensor 100 is identical, and this will not be detailed here.The difference of the two is only described below
Place.
The ultrasonic transducer 220 includes the mask layer 123 and insulating layer 126 on the cmos circuit 110, and
Laminated piezoelectric on mask layer 123.The covering of mask layer 123 and surrounding cavity 152.Mask layer 123 includes opening
151, which is used for the discharge into passage and etch products that etchant is provided in the forming process of cavity 152
Passage.In a preferred embodiment, be open 151 substantially 0.1 micron to 0.8 micron of lateral dimension.Insulating layer 126 is positioned at sky
On chamber 152.The closing of insulating layer 126 opening 151, and the laminated piezoelectric to subsequently form provide mechanical support effect.
The laminated piezoelectric of the ultrasonic transducer 220 includes the Seed Layer 131, first electrode 132, piezoelectric layer stacked gradually
133 and second electrode 135.In an alternative embodiment, if forming Seed Layer 131,131 envelope of Seed Layer can be used
The opening 151 in mask layer 123 is closed, so as to save insulating layer 126., can be in mask layer in another alternative embodiment
Additional sealant is formed on 123 to close the opening 151 in mask layer 123, insulating layer 126 is then formed, so as to carry
The intensity of high mechanical support.
Further, ultrasonic fingerprint sensor 200, which further includes, is used for cmos circuit 110 and ultrasonic transducer 220
The first contact 136 being electrically connected to each other and the second contact 137.Same conductive layer can be used to form second electrode 135, first
136 and second contact 137 of contact.First contact 136 is connected under piezoelectric layer 133 via the through hole through piezoelectric layer 133
The first electrode 132 of side, and it is connected to the second wiring layer via the through hole 153 of the second wiring layer 109 of arrival of piezoelectric layer 133
109.Second contact 137 is connected to second electrode 135, and the through hole 153 of the second wiring layer 109 is reached via piezoelectric layer 133
It is connected to the second wiring layer 109.The side wall of the through hole 153 could be formed with insulating layer 134 and be used as lining so that the first contact
136 and second contact 137 be dielectrically separated from the remainder of laminated piezoelectric.Further, the second wiring layer 109 can connect warp
First wiring layer 107 is connected to by conductive channel, and then is connected to the active area of cmos circuit 110.In this embodiment, it is located at
Conductive material in through hole 153 forms conductive channel.Therefore, two apparent surfaces of the piezoelectric layer 133 in ultrasonic transducer,
It is utilized respectively the first contact 136 and second and contacts 137 cmos circuits 110 being connected to below ultrasonic transducer.
In this embodiment, ultrasonic fingerprint sensor 200 is included in the ultrasonic transducer stacked on cmos circuit 110
220, any one in the second interlayer dielectric layer 108 of cmos circuit 110, mask layer 123, insulating layer 126 and Seed Layer 131 can
To be made of insulating materials, and as the insulating layer for being used to cmos circuit 110 and ultrasonic transducer 220 being spaced apart.
Compared with ultrasonic fingerprint sensor 100 according to second embodiment, ultrasonic fingerprint sensor 200 according to third embodiment
The quantity of insulating layer can be further reduced, so as to reduce device volume and reduce manufacture cost.
Fig. 6 shows the schematic cross-section of the ultrasonic fingerprint sensor 300 according to the utility model fourth embodiment.This is super
Sound wave fingerprint sensor 300 includes the cmos circuit 110 and ultrasonic transducer 320 stacked.
Cmos circuit 110 in the ultrasonic fingerprint sensor 300 of fourth embodiment with it is according to second embodiment
Cmos circuit 110 in ultrasonic fingerprint sensor 100 is identical, and this will not be detailed here.The difference of the two is only described below
Place.
The ultrasonic transducer 320 includes the mask layer 123 and insulating layer 126 on the cmos circuit 110, and
Laminated piezoelectric on mask layer 123.The covering of mask layer 123 and surrounding cavity 152.Mask layer 123 includes opening
151, which is used for the discharge into passage and etch products that etchant is provided in the forming process of cavity 152
Passage.In a preferred embodiment, be open 151 substantially 0.1 micron to 0.8 micron of lateral dimension.Insulating layer 126 is positioned at sky
On chamber 152.The closing of insulating layer 126 opening 151, and the laminated piezoelectric to subsequently form provide mechanical support effect.
The laminated piezoelectric of the ultrasonic transducer 320 includes the Seed Layer 131, first electrode 132, piezoelectric layer stacked gradually
133 and second electrode 135.In an alternative embodiment, if forming Seed Layer 131,131 envelope of Seed Layer can be used
The opening 151 in mask layer 123 is closed, so as to save insulating layer 126., can be in mask layer in another alternative embodiment
Additional sealant is formed on 123 to close the opening 151 in mask layer 123, insulating layer 126 is then formed, so as to carry
The intensity of high mechanical support.
Further, ultrasonic fingerprint sensor 300, which further includes, is used for cmos circuit 110 and ultrasonic transducer 320
The first contact 136 being electrically connected to each other and the second contact 137.Same conductive layer can be used to form first electrode 132 and the
One contact 136, and same conductive layer form the contact of second electrode 135 and second 137.First contact 136 and first electrode
132 are connected to each other, and the first through hole that the second wiring layer 109 is reached via the lower surface of piezoelectric layer 133 is connected to the second wiring layer
109.Second contact 137 is connected to each other with second electrode 135, and reaches the second wiring layer via the upper surface of piezoelectric layer 133
109 the second through hole is connected to the second wiring layer 109.The side wall of first through hole and the second through hole could be formed with insulating layer 134
As lining so that the first contact 136 and the second contact 137 and the remainder of laminated piezoelectric are dielectrically separated from.First contact 136
The side wall of first through hole can be located at and bottom, piezoelectric layer 133 further fill first through hole.Further, the second wiring layer
109 can connect and be connected to the first wiring layer 107 via conductive channel, and then be connected to the active area of cmos circuit 110.At this
In embodiment, the conductive material in through hole forms conductive channel.Therefore, two of the piezoelectric layer 133 in ultrasonic transducer
A apparent surface, it is electric to be utilized respectively the CMOS that the first contact 136 and the second contact 137 are connected to below ultrasonic transducer
Road 110.
In this embodiment, ultrasonic fingerprint sensor 300 is included in the ultrasonic transducer stacked on cmos circuit 110
320, the first contact 136 is extended to the second wiring layer 109 from the lower surface of piezoelectric layer 133, and second contacts 137 from piezoelectric layer
133 upper surface extends to the second wiring layer 109.Compared with ultrasonic fingerprint sensor 100 according to second embodiment, according to
The ultrasonic fingerprint sensor 300 of fourth embodiment first contact 136 be located at piezoelectric layer 133 lower surfaces, because without
Through hole is formed on piezoelectric layer 133.The ultrasonic fingerprint sensor 300 can maintain the integrality of piezoelectric layer 133 and machinery strong
Degree, so as to further improve the reliability of ultrasonic transducer, and improves the acoustical behavior of ultrasonic transducer.
Fig. 7 shows the schematic cross-section of the ultrasonic fingerprint sensor 400 according to the 5th embodiment of the utility model.This is super
Sound wave fingerprint sensor 400 includes the cmos circuit 110 and ultrasonic transducer 420 stacked.
Cmos circuit 110 in the ultrasonic fingerprint sensor 400 of the 5th embodiment with it is according to second embodiment
Cmos circuit 110 in ultrasonic fingerprint sensor 100 is identical, and this will not be detailed here.The difference of the two is only described below
Place.
The ultrasonic transducer 420 includes the mask layer 123 and insulating layer 126 on the cmos circuit 110, and
Laminated piezoelectric on mask layer 123.The covering of mask layer 123 and surrounding cavity 152.Mask layer 123 includes opening
151, which is used for the discharge into passage and etch products that etchant is provided in the forming process of cavity 152
Passage.In a preferred embodiment, be open 151 substantially 0.1 micron to 0.8 micron of lateral dimension.Insulating layer 126 is positioned at sky
On chamber 152.The closing of insulating layer 126 opening 151, and the laminated piezoelectric to subsequently form provide mechanical support effect.
The laminated piezoelectric of the ultrasonic transducer 420 includes the Seed Layer 131, first electrode 132, piezoelectric layer stacked gradually
133 and second electrode 135.In an alternative embodiment, if forming Seed Layer 131,131 envelope of Seed Layer can be used
The opening 151 in mask layer 123 is closed, so as to save insulating layer 126., can be in mask layer in another alternative embodiment
Additional sealant is formed on 123 to close the opening 151 in mask layer 123, insulating layer 126 is then formed, so as to carry
The intensity of high mechanical support.
Further, ultrasonic fingerprint sensor 400, which further includes, is used for cmos circuit 110 and ultrasonic transducer 420
The first contact 136 being electrically connected to each other and the second contact 137.Same conductive layer can be used to form first electrode 132 and the
One contact 136, and same conductive layer form the contact of second electrode 135 and second 137.First contact 136 and first electrode
132 are connected to each other, and the first through hole that the second wiring layer 109 is reached via the lower surface of piezoelectric layer 133 is connected to the second wiring layer
109.Second contact 137 is connected to each other with second electrode 135, and reaches the first wiring layer via the upper surface of piezoelectric layer 133
107 the second through hole is connected to the first wiring layer 107.The side wall of first through hole and the second through hole could be formed with insulating layer 134
As lining so that the first contact 136 and the second contact 137 and the remainder of laminated piezoelectric are dielectrically separated from.First contact 136
The side wall of first through hole can be located at and bottom, piezoelectric layer 133 further fill first through hole.Further, the first wiring layer
107 and second wiring layer 109 can be connected to the active area of cmos circuit 110.In this embodiment, the conduction in through hole
Material forms conductive channel.Therefore, two apparent surfaces of the piezoelectric layer 133 in ultrasonic transducer, are utilized respectively first and connect
Touch 136 and second and contact 137 cmos circuits 110 being connected to below ultrasonic transducer.
In this embodiment, ultrasonic fingerprint sensor 400 is included in the ultrasonic transducer stacked on cmos circuit 110
420, the first contact 136 extends to the second wiring layer 109 from the lower surface of piezoelectric layer 133, and second contacts 137 from piezoelectric layer 133
Upper surface extend to the first wiring layer 107.Compared with ultrasonic fingerprint sensor 100 according to second embodiment, according to
The ultrasonic fingerprint sensor 400 of five embodiments first contact 136 be located at piezoelectric layer 133 lower surfaces, because without
Through hole is formed on piezoelectric layer 133.The ultrasonic fingerprint sensor 400 can maintain the integrality and mechanical strength of piezoelectric layer 133,
So as to further improve the reliability of ultrasonic transducer, and improve the acoustical behavior of ultrasonic transducer.Further, surpass
First contact 136 of acoustic wave transducer 420 and the second contact 137 can be directly connected to the wiring layer of different level, so as to keep away
The rewiring exempted from wiring layer produces dead resistance and parasitic capacitance, further improves the response speed of ultrasonic transducer.
Fig. 8 shows the operation principle schematic diagram of ultrasonic fingerprint sensor.Fingerprint sensor bag according to the present utility model
Include the cmos circuit 210 and ultrasonic transducer 220 being connected to each other.Preferably, ultrasonic transducer 220 includes multiple ultrasonic waves
The M N array that transducer unit 240 forms, wherein, M and N are respectively natural number.Multiple cmos circuits 210 form signal processing
Circuit, ultrasonic transducer unit 240 are stacked on the top of cmos circuit 210.
The stage is produced in ultrasonic wave, signal processing circuit provides pulse electrical signal, makes the piezoelectricity in ultrasonic transducer 220
Inverse piezoelectric effect occurs for layer, and high frequency machinery deformation produces ultrasonic signal.The stage is received in ultrasonic wave, since ultrasonic wave runs into difference
Sound-resistance material, ultrasonic signal have a different reflectivity, and different convex, recessed figures causes ultrasonic transducer receiving in fingerprint
To different ultrasonic signals, stronger direct piezoelectric effect occurs in ultrasonic reflection cavity region.Signal processing circuit is according to electric signal
The ultrasonic signal that ultrasonic transducer 220 is fed back is handled, reads the fingerprint signal of formation.
The array of multiple ultrasonic transducer units 240 composition in ultrasonic transducer 220 is only shown in fig. 8.
The ultrasonic transducer unit 240 produces ultrasonic wave by direct piezoelectric effect, and ultrasonic wave vertically advances use " ↑ " symbolic indication, surpasses
Sound reflecting meets expression with " ↓ ".In the convex domain of the finger part of people, ultrasonic wave can largely pass through human skin tissue, quilt
Human skin tissue absorbs；In the concave region of finger, ultrasonic wave is largely reflected, and is returned inside ultrasonic transducer, production
Raw direct piezoelectric effect.The difference of signal, identification identification finger print information are received by fingerprint sensor array.
In terms of the manufacturing, the ultrasonic fingerprint sensor manufacturing process is compatible with CMOS technology, can be produced in CMOS
Line is directly processed.In terms of ultrasonic transducer subsequent applications, application neck of the ultrasonic fingerprint sensor in subsequent movement terminal
Domain can penetrate the media such as glass and directly apply, reduce follow-up application cost without the perforate on the media such as glass.In terminal
Application aspect, compared with capacitive fingerprint sensing device, the ultrasonic signal of ultrasonic fingerprint sensor is influenced by greasy dirt, sweat etc.
It is small, small, the high accuracy for examination of identification is influenced with humidity by temperature.
It should be noted that herein, relational terms such as first and second and the like are used merely to a reality
Body or operation are distinguished with another entity or operation, are deposited without necessarily requiring or implying between these entities or operation
In any this actual relation or order.Moreover, term " comprising ", "comprising" or its any other variant are intended to
Non-exclusive inclusion, so that process, method, article or equipment including a series of elements not only will including those
Element, but also including other elements that are not explicitly listed, or further include as this process, method, article or equipment
Intrinsic key element.In the absence of more restrictions, the key element limited by sentence "including a ...", it is not excluded that
Also there are other identical element in process, method, article or equipment including the key element.
As described above, these embodiments do not have all details of detailed descriptionthe to embodiment according to the utility model,
Also it is only the specific embodiment not limit the utility model.Obviously, as described above, many modification and change can be made
Change.This specification is chosen and specifically describes these embodiments, and being should in order to preferably explain the principle and reality of the utility model
With so that skilled artisan can repairing using the utility model and on the basis of the utility model well
Change use.The utility model is limited only by the claims and their full scope and equivalents.
Claims (23)
1. a kind of ultrasonic transducer, for producing ultrasonic wave according to drive signal and producing detection signal according to echo, its
It is characterized in that, including：
Mask layer, the mask layer covering and surrounding cavity, and including extending to the opening of the cavity from surface；And
Laminated piezoelectric on the mask layer.
2. ultrasonic transducer according to claim 1, it is characterised in that further include：Below the mask layer
First insulating layer.
3. ultrasonic transducer according to claim 1, it is characterised in that further include：It is close on the mask layer
Sealing, the sealant close the opening.
4. ultrasonic transducer according to any one of claim 1 to 3, further includes second on the mask layer
Insulating layer.
5. ultrasonic transducer according to claim 4, it is characterised in that second insulating layer closes the opening.
6. ultrasonic transducer according to claim 4, it is characterised in that the laminated piezoelectric includes：
Piezoelectric layer on second insulating layer；And
The lower surface of the piezoelectric layer and the first electrode of upper surface and second electrode are contacted respectively.
7. ultrasonic transducer according to claim 6, it is characterised in that further include：
Seed Layer between second insulating layer and the piezoelectric layer.
8. ultrasonic transducer according to claim 7, it is characterised in that the piezoelectric layer and the Seed Layer respectively by
In aluminium nitride, segregation vinyl fluoride, segregation vinyl fluoride-trifluoro-ethylene, lead titanate piezoelectric ceramics, lithium niobate piezoelectric ceramics
Any one composition.
9. ultrasonic transducer according to claim 1, it is characterised in that the lateral dimension of the opening is 0.1 micron
To 0.8 micron.
10. ultrasonic transducer according to claim 1, it is characterised in that the mask layer is made of corrosion resistant material.
11. ultrasonic transducer according to claim 10, it is characterised in that the corrosion resistant material is included selected from oxidation
Any one in silicon, silicon nitride, carborundum, gold, copper.
12. ultrasonic transducer according to claim 6, it is characterised in that further include：
Connected with the first electrode and provide the first of external connection and contacted；And
Connected with the second electrode and provide the second of external connection and contacted.
13. ultrasonic transducer according to claim 12, it is characterised in that described first contacts from the piezoelectric layer
Upper surface reaches the first electrode through the piezoelectric layer.
14. ultrasonic transducer according to claim 12, it is characterised in that the first electrode is contacted with described first
Formed by identical conductive layer patternization and be connected to each other.
15. ultrasonic transducer according to claim 12, it is characterised in that the second electrode is contacted with described second
Formed by identical conductive layer patternization and be connected to each other.
A kind of 16. ultrasonic fingerprint sensor, it is characterised in that including：
Cmos circuit；And
At least one ultrasonic transducer according to any one of claim 1 to 15,
Wherein, the cmos circuit is connected with the ultrasonic transducer, for driving at least one ultrasonic transducer
With the detection signal for handling at least one ultrasonic transducer generation.
17. ultrasonic fingerprint sensor according to claim 16, it is characterised in that the cmos circuit include substrate and
At least one transistor formed on substrate.
18. ultrasonic fingerprint sensor according to claim 17, it is characterised in that the cmos circuit, which further includes, to be located at
Multiple wiring layers and multiple interlayer dielectric layers at least one transistor, the multiple wiring layer is by the multiple interlayer
Dielectric layer is separated into multiple and different aspects.
19. ultrasonic fingerprint sensor according to claim 18, it is characterised in that the laminated piezoelectric includes piezoelectric layer
And the lower surface of the piezoelectric layer and the first electrode of upper surface and second electrode are contacted respectively, the first electrode and described
Second electrode is connected at least one transistor via at least one wiring layer.
20. ultrasonic fingerprint sensor according to claim 19, it is characterised in that at least one ultrasonic wave transducer
Device further includes：
Respectively with the first electrode and the second electrode connect first contacts and second contacts；
The first through hole and the second through hole of at least one wiring layer are reached from the piezoelectric layer upper surface；And
The 3rd insulating layer on the side wall of the first through hole and second through hole,
Wherein, first contact and the described second contact extend to institute via the first through hole and second through hole respectively
State at least one wiring layer.
21. ultrasonic fingerprint sensor according to claim 19, it is characterised in that at least one ultrasonic wave transducer
Device further includes：
Respectively with the first electrode and the second electrode connect first contacts and second contacts；
The first through hole of at least one wiring layer is reached from the piezoelectric layer lower surface；
The second through hole of at least one wiring layer is reached from the piezoelectric layer upper surface；
The 3rd insulating layer on the side wall of the first through hole,
The 4th insulating layer on the side wall of second through hole,
Wherein, first contact and the described second contact extend to institute via the first through hole and second through hole respectively
State at least one wiring layer.
22. ultrasonic fingerprint sensor according to claim 16, it is characterised in that further include：Positioned at CMOS electricity
Passivation layer on road.
23. ultrasonic fingerprint sensor according to claim 16, it is characterised in that at least one ultrasonic wave transducer
Device forms array.
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| CN201720396599.4U CN207254707U (en) | 2017-04-14 | 2017-04-14 | Ultrasonic transducer and ultrasonic fingerprint sensor |
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|---|---|---|---|
| CN201720396599.4U CN207254707U (en) | 2017-04-14 | 2017-04-14 | Ultrasonic transducer and ultrasonic fingerprint sensor |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107199169A (en) * | 2017-04-14 | 2017-09-26 | 杭州士兰微电子股份有限公司 | Ultrasonic transducer, ultrasonic fingerprint sensor and its manufacture method |
| CN108985280A (en) * | 2018-08-31 | 2018-12-11 | 东莞新科技术研究开发有限公司深圳分公司 | Ultrasonic fingerprint sensor and preparation method thereof, application |
| CN111151431A (en) * | 2018-11-08 | 2020-05-15 | 格芯新加坡私人有限公司 | Piezoelectric micromechanical ultrasonic transducer and method for producing same |
| WO2020215928A1 (en) * | 2019-04-24 | 2020-10-29 | 京东方科技集团股份有限公司 | Ultrasonic fingerprint recognition device and display device |
| WO2020238313A1 (en) * | 2019-05-24 | 2020-12-03 | 京东方科技集团股份有限公司 | Display substrate for ultrasonic fingerprint recognition, manufacturing method therefor, and display device |
| TWI733208B (en) * | 2019-10-03 | 2021-07-11 | 佳世達科技股份有限公司 | Ultrasonic probe and manufacturing method thereof |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107199169A (en) * | 2017-04-14 | 2017-09-26 | 杭州士兰微电子股份有限公司 | Ultrasonic transducer, ultrasonic fingerprint sensor and its manufacture method |
| CN108985280A (en) * | 2018-08-31 | 2018-12-11 | 东莞新科技术研究开发有限公司深圳分公司 | Ultrasonic fingerprint sensor and preparation method thereof, application |
| CN111151431A (en) * | 2018-11-08 | 2020-05-15 | 格芯新加坡私人有限公司 | Piezoelectric micromechanical ultrasonic transducer and method for producing same |
| US11329098B2 (en) | 2018-11-08 | 2022-05-10 | Vanguard International Semiconductor Singapore Pte. Ltd. | Piezoelectric micromachined ultrasonic transducers and methods for fabricating thereof |
| WO2020215928A1 (en) * | 2019-04-24 | 2020-10-29 | 京东方科技集团股份有限公司 | Ultrasonic fingerprint recognition device and display device |
| WO2020238313A1 (en) * | 2019-05-24 | 2020-12-03 | 京东方科技集团股份有限公司 | Display substrate for ultrasonic fingerprint recognition, manufacturing method therefor, and display device |
| TWI733208B (en) * | 2019-10-03 | 2021-07-11 | 佳世達科技股份有限公司 | Ultrasonic probe and manufacturing method thereof |
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