CN108649916A - A kind of outbound course of thin film bulk acoustic wave resonator and its back electrode - Google Patents
A kind of outbound course of thin film bulk acoustic wave resonator and its back electrode Download PDFInfo
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- CN108649916A CN108649916A CN201810360564.4A CN201810360564A CN108649916A CN 108649916 A CN108649916 A CN 108649916A CN 201810360564 A CN201810360564 A CN 201810360564A CN 108649916 A CN108649916 A CN 108649916A
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Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
- H03H2003/023—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks the resonators or networks being of the membrane type
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
The invention belongs to the technical field of thin film bulk acoustic wave resonator, the outbound course of a kind of thin film bulk acoustic wave resonator and its back electrode is disclosed.The thin film bulk acoustic wave resonator includes substrate, back electrode and piezoelectric layer are disposed on substrate, the surface of substrate is equipped with groove, the groove of back electrode and substrate surface forms air chamber, piezoelectric layer is equipped with through-hole, the lower section of through-hole is back electrode, and the piezoelectric layer of through-hole side is equipped with top electrode, back electrode material is equipped in the other side of through-hole and through-hole.Back electrode outbound course mainly prepares through-hole on piezoelectric membrane, and the lower section of through-hole is back electrode, deposits top electrode on the piezoelectric membrane of through-hole side, and deposition has back electrode material, back electrode to be drawn by through-hole on the piezoelectric membrane of the through-hole other side and in through-hole.The present invention eliminates large area etching piezoelectric membrane, smaller to thin film damage；Through-hole extraction electrode easily covers；And the present invention can reduce device size, reduce power consumption and improving performance.
Description
Technical field
The invention belongs to the technical fields of thin film bulk acoustic wave resonator, and in particular to a kind of thin film bulk acoustic wave resonator and its
The outbound course of back electrode.
Background technology
Nearly ten years, the requirement due to field of Internet communication to radio frequency receiving signal technology is constantly got higher, thin-film body sound
The advantage of wave resonator (FBAR) technology itself gradually presents out.A very important part is in mobile communication terminal
Radio-frequency filter, in the past, mobile phone usually only works in a small number of frequency ranges of global given area, however current mobile phone is substantially
It can work in multiple radio bands in same time, therefore mobile-phone manufacturers are had begun to expand and be solved using FBAR technologies
4G/LTE problem encountered.The area such as the U.S., Europe and Asia 15 is had been introduced into using the filter of FBAR technologies at present
Among the smart mobile phone design of a different operating frequency range, FBAR technologies have become mainstream, and the market demand is huge.At this stage, perhaps
Multiple semiconductor manufacturing company and academic institution's unit have all put into plenty of time and energy in FBAR technical research.Meanwhile it is right
The research range of FBAR science is gradually expanded, including the propagation model, material of FBAR preparation and property and FBAR passing
The application in sensor direction.
During to FBAR chip testings RF (radio frequency) and microwave feature, the spy of ground-signal-ground (GSG) is usually used
Needle constructs, and realizes the structure of co-planar waveguide, is fed with reaching desirable accuracy and characteristic impedance, this requires bare chips to exist
Signal end and ground terminal needs are generally aligned in the same plane when GSG is tested.To meet this requirement, traditional handicraft utilizes in substrate successively
Back electrode, piezoelectric membrane and top electrode are deposited, forms the pattern of Step Coverage, the gold of top electrode by the method for etching or corroding
Belong to the step that the piezoelectric membrane after covering etching is formed, the process of plane where extending to back electrode.This process
Middle top electrode guides to back electrode table top, and the process is more complicated, and the electrode spreadability at step is poor, electrode film and pressure
There is very big stress in conductive film interface.
Invention content
In order to overcome the shortcomings and deficiencies of the prior art, the purpose of the present invention is to provide a kind of thin film bulk acoustic wave resonator
The outbound course of middle back electrode and the thin film bulk acoustic wave resonator obtained by this method.The present invention prepares logical on piezoelectric membrane
Hole, then the deposition of electrode material in the surface of piezoelectric membrane and through-hole, the back electrode below piezoelectric membrane pass through logical
Piezoelectric layer upper surface is guided in hole.The present invention can avoid asking for metal step coverage difference that may be present using metal throuth hole
Topic.Also, back electrode is drawn by through-hole, electrode line length can be shortened, reduces device size and parasitic parameter, is conducive to drop
Low-power consumption promotes device performance, is suitably applied the manufacture of the radio-frequency filter of high-frequency high-power occasion.
The purpose of the present invention is realized by following technology：
Back electrode outbound course in a kind of thin film bulk acoustic wave resonator, includes the following steps：
It is set on surface and is sequentially depositing back electrode and piezoelectric membrane on reeded substrate, the groove of back electrode and substrate surface
Air chamber is formed, through-hole is then prepared on piezoelectric membrane, the lower section of through-hole is back electrode, is sunk on the piezoelectric membrane of through-hole side
Product top electrode, deposition has back electrode material, the piezoelectricity of the through-hole other side thin on the piezoelectric membrane of the through-hole other side and in through-hole
Back electrode material successive sedimentation on film and in through-hole, back electrode are drawn by through-hole, and back electrode is led to piezoelectric membrane
Surface.
The through-hole refers to the photoetching that via hole image is first carried out to piezoelectric membrane, is then formed by etching.
The substrate is silicon, sapphire, SiC etc., and the piezoelectric membrane is AlN, ZnO, lead zirconate titanate etc..
The top electrode has interval with back electrode material.The back of the body electricity of the top electrode and in through-hole and piezoelectric membrane surface
There is interval between the material of pole.
Back electrode outbound course, specifically includes following steps in the thin film bulk acoustic wave resonator：
(1) it is set on surface and is sequentially depositing back electrode and piezoelectric membrane on reeded substrate, obtain piezoelectric membrane/back of the body electricity
Pole/substrate；
(2) piezoelectric membrane/back electrode/substrate is pre-processed, the impurity on removal piezoelectric membrane surface；
(3) pretreated piezoelectric membrane will be passed through and carries out photoetching, and etched, through-hole is obtained on piezoelectric membrane；The photoetching
Photoresist is positive photoresist；
(4) piezoelectric membrane/back electrode/substrate for being etched with through-hole is cleaned, removes impurity；Then in through-hole side
Piezoelectric membrane on by electron beam evaporation deposition method be deposited top electrode material, in through-holes and the piezoelectricity of the through-hole other side is thin
Back electrode material is deposited by electron beam evaporation deposition method on film, back electrode leads to the surface of piezoelectric membrane by through-hole.
Step (3) the specific steps are：
Piezoelectric membrane surface vapor at counterdie (adhesion promoting layer), spin coating positive photoresist is dry, by there is via hole image
Mask plate be exposed, developer solution impregnate, performed etching according to the figure of through-hole, obtain through-hole.The condition of exposure is 300-
340W exposure powers expose 3-5s.Developer solution soaking time is 40-60s.
The method deposited in step (1) is the deposition method of routine, the deposition methods such as such as MOCVD, PLD；
Pretreatment refers to being ultrasonically treated with acetone in step (1), is then cleaned successively with ethyl alcohol, water, then with by H2SO4、
H2O2With H2The solution that O is formulated is impregnated, then is impregnated with HF solution, is eluted with water, and is dried.
Cleaning described in step (4) refers to using salt acid soak, is eluted with water.
Top electrode material described in step (4) and back electrode material are Ti, Pt, Al alone, and Au etc. is suitble to be steamed with electron beam
The metal of hair method deposition.
The thin film bulk acoustic wave resonator of the present invention, including substrate are disposed with back electrode and piezoelectric layer on the substrate,
The surface of the substrate is equipped with groove, the groove formation air chamber of back electrode and substrate surface, and the piezoelectric layer is equipped with through-hole, leads to
The lower section in hole is back electrode, and the piezoelectric layer of through-hole side is equipped with top electrode, back of the body electricity is equipped in the other side of through-hole and through-hole
Pole material.There is interval between top electrode and back electrode material.
The present invention coats after photoresist carries out photoetching on piezoelectric membrane and etches through-hole, then passes through electron beam evaporation handle
On electrode material vapor deposition to piezoelectric layer, the back electrode under such piezoelectric layer can guide to piezoelectric layer upper surface by through-hole.From work
For skill angle, deposition top electrode utilizes metal throuth hole to the complicated technology of the table top of back electrode after improving etching AlN film layer
It can avoid the problem of metal step coverage difference that may be present.Also, back electrode is drawn by through-hole, electrode can be shortened
Line length reduces device size and parasitic parameter, advantageously reduces power consumption, promotes device performance, is suitably applied the big work(of high frequency
The manufacture of the radio-frequency filter of rate occasion.
Compared with traditional process deposits top electrode, the present invention has the following advantages and beneficial effect：
1, the present invention eliminates large area etching piezoelectric membrane (such as：AlN), smaller to thin film damage；
2, traditional handicraft step coverage is poor, and the present invention is easier to cover by through-hole extraction electrode；
3, the present invention can shorten electrode line length, reduce device size, reduce power consumption and improving performance；
4, actual process of the present invention thermally expands reliability height, and parasitic parameter is small.
Description of the drawings
Fig. 1 is the structural schematic diagram for the thin film bulk acoustic wave resonator that (b) of the invention is prepared with traditional handicraft (a)；
Fig. 2 is that the SEM on piezoelectric membrane before the non-evaporation metal material of through-hole schemes (vertical view)；(a) it is that piezoelectricity is thin in embodiment 1
The SEM figures of through-hole are etched on film AlN, are (b) the SEM figures for etching through-hole in embodiment 2 on piezoelectric membrane AlN；
Fig. 3 is the energy spectrum diagram in through-hole after electrode evaporation in embodiment 1 and embodiment 2；(a) scanning electron microscope of embodiment 1
The stereoscan photograph and energy spectrum diagram (1500 times) of photo and energy spectrum diagram (1500 times) (b) embodiment 2；
Fig. 4 is the bias-capacitance curve and bias-loss angle of thin film bulk acoustic wave resonator in embodiment 1 and embodiment 2
Tangent cutve；
Fig. 5 is the frequency-capacitance and frequency-loss angle tangent of thin film bulk acoustic wave resonator in embodiment 1 and embodiment 2
Curve.
Specific implementation mode
With reference to embodiment and attached drawing, the present invention is described in further detail, but embodiments of the present invention are not
It is limited to this.
The structural schematic diagram for the thin film bulk acoustic wave resonator that the present invention is prepared with traditional handicraft is as shown in Figure 1, wherein a is to pass
Thin film bulk acoustic wave resonator prepared by technique of uniting, b are thin film bulk acoustic wave resonator prepared by the present invention.
Thin film bulk acoustic wave resonator prepared by traditional handicraft, including substrate 1 are disposed with sacrificial layer 2 and the back of the body on substrate
Electrode 3, the surface of the sacrificial layer are equipped with groove, and the groove of back electrode and sacrificial layer surface forms air chamber, and back electrode is endless
All standing sacrificial layer, on back electrode and the sacrificial layer by back electrode covering is equipped with piezoelectric layer 4, and piezoelectric layer is not completely covered
Sacrificial layer, on piezoelectric layer and the sacrificial layer by piezoelectric layer covering is equipped with top electrode 5.
The thin film bulk acoustic wave resonator of the present invention, including substrate 1 are disposed with back electrode 2 and piezoelectricity on the substrate
The surface of layer 3, the substrate is equipped with groove, and the groove formation air chamber of back electrode and substrate surface, the piezoelectric layer is equipped with logical
The lower section in hole 5, through-hole is back electrode, and the piezoelectric layer of through-hole side is equipped with top electrode 4, is set in the other side of through-hole and through-hole
There is back electrode material.There is interval between top electrode and back electrode material.The top electrode and in through-hole and piezoelectric membrane surface
There is interval between back electrode material.
Embodiment 1
The thin film bulk acoustic wave resonator of the present embodiment, including substrate Si are disposed with back electrode Ti on the Si substrates
It is equipped with groove, the groove formation air chamber of back electrode and substrate surface, the piezoelectricity with the surface of piezoelectric layer AlN, the substrate
Layer AlN is equipped with through-hole, and the lower section of through-hole is back electrode, and the piezoelectric layer AlN of through-hole side is equipped with top electrode Ti, through-hole it is another
Back electrode material Ti is equipped in side and through-hole.There is interval between top electrode and back electrode material.Substrate thickness is 430 μm, back of the body electricity
The thickness of pole is 100nm, and the thickness of piezoelectric layer is 1.5 μm, and the thickness of top electrode is 100nm, the back electrode material of piezoelectric layer surface
The thickness of material is 100nm.
The extraction of back electrode in the thin film bulk acoustic wave resonator, including following steps：
(1) it is sequentially depositing (the methods of MOCVD, PLD) back electrode Ti and piezoelectric membrane AlN on a si substrate, obtains AlN/
Ti/Si；
(2) AlN/Ti/Si film cleanings：Acetone 40kHz ultrasound 5min are first used, uses ethyl alcohol, water to clean respectively, removes surface
Organic pollution；Solution (the H now matched with 40 DEG C again2SO4(concentration 98%)：H2O2(concentration 35%)：H2O volume ratios are=1:
3:3) cleaning sample 10min, HF solution (HF (40%)：H2Volume ratio=1 O:10) cleaning sample 10min is eluted with water, removal
The inorganic pollution on surface, drying；
(3) photoetching of through-hole：Pretreated AlN/Ti/Si is put into the inflation of HMDS ovens, forming HMDS on the surfaces AlN increases
Adhesion coating；Spin coating RJZ-304 type positive photoresists, 100 DEG C of baking 100s remove partial moisture；By there is the mask of via hole image
Then version exposes (300-340W exposure powers expose 3-5s)；It is put into TMAH developer solutions and impregnates 60s, finally check figure line
It is wide whether qualified；The piezoelectric membrane after photoetching is passed through 60sccm oxygen plasmas in sense coupling machine again
300s is handled under the power of 80W, removes residue glue；
(4) etching of through-hole：
The piezoelectric membrane for removing residue glue performs etching according to the figure that photoresist is formed to (etching through hole pattern will be integrated and be examined
The smoothness for considering etching, the conflict between damage and high selectivity etching to AlN), setting inductively coupled plasma is carved
Erosion machine technological parameter：The pressure of reaction chamber is 4mTorr, and upper/lower electrode power is respectively 330W/180W, and etching gas is
100sccmCl2/30sccmBCl3, pallet He flows be 4Torr, 0 DEG C of chassis temperature, piezoelectric membrane etch through-hole SEM shine
Shown in piece such as Fig. 2 (a), through-hole diameter is 50 μm；
(5) cleaning before copper plating is steamed：
Evaporation process is very high to the clean level requirement of substrate surface, and out-of-flatness or dirty surface can lead to metal foil
The consequence that film falls off；Need will to etch the AlN/Ti/Si of through-hole before vapor deposition with volume ratio HCl (37%)：H2O=1:1 hydrochloric acid
Solution cleans 10min, bath drying；
(6) AlN/Ti/Si for etching through-hole cleaned is fixed on sample stage and is put into vacuum chamber, thick suction
Reach 10-2Pa, open molecular pump and vacuumize ＜ 10-4Pa, opens electron beam line switch and prepare to start plated film；Wait for crystal oscillator film thickness
After the rate stabilization shown on instrument, baffle is opened, target is bombarded using high-power electron beam, evaporates target metal Ti, make electrode material
Material after vacuum transport to film surface by condensing come electrode evaporation film；The data that observation film thickness gauge is shown therebetween, control beam
Flow power and beam spot position, set evaporation rate asThe consistency and vapor deposition efficiency of counter electrode film, metallic film
Energy spectrum analysis as shown in Figure 3 (Fig. 3 is the energy spectrum diagram in through-hole after electrode evaporation), it can be seen that Ti is inside and outside through-hole, side wall
It is uniformly distributed.
Thin film bulk acoustic wave resonator manufactured in the present embodiment is fixed on fixture and carries out testing impedance.Including with SZT-2A
Four probe resistance instrument carry out resistivity measurement, and carrying out the electric property under different biass with Agilent 4294A impedance analyzers surveys
Electrical performance testing under examination and different frequency sweeps, film (thin film bulk acoustic wave resonator) resistivity are 47.36k ω/cm.It is different inclined
The electrical performance testing reflection of pressure is static electric property of the film under continuous current excitation, including the dielectric constant of film and
Loss angle tangent, inherence frequency 10kHz, setting bias are scanned from -3V~3V.(Fig. 4 is thin-film body sound as shown in Figure 4
Bias-capacitance curve and bias-loss angle tangent curve of wave resonator), the change of Dc bias hardly influences thin
The direct capacitance size of film.C=1.07pF calculates ε r=2.46 according to capacitance calculation formula C=ε r ε 0*S/d.Although pressure
Electric material thickness under the Dc bias added outside can change, so as to cause the capacitance variations of film.But herein almost without
It influences, it may be possible to because the presence of Si substrates discharges the thickness change of piezoelectric membrane AlN.
What the electrical performance testing under different frequency sweeps reflected is dielectric constant and loss of the film under alternating current excitation
Angle tangent, is the frequency individual features of film, fixed-bias transistor circuit 1V, and scan frequency is from 1-1000kHz.(Fig. 5 is as shown in Figure 5
Frequency-capacitance and frequency-loss angle tangent curve of thin film bulk acoustic wave resonator), dielectric loss is damaged at low frequency by conductance
Consumption is leading.It is increased with the frequency of alternating electric field, starts the case where polarisation hysteresis electrode variation occur, example dielectric characteristic becomes
More meet piezoelectric material.
Embodiment 2
The thin film bulk acoustic wave resonator of the present embodiment, including substrate Si are disposed with back electrode Ti on the Si substrates
It is equipped with groove, the groove formation air chamber of back electrode and substrate surface, the piezoelectricity with the surface of piezoelectric layer AlN, the substrate
Layer AlN is equipped with through-hole, and the lower section of through-hole is back electrode, and the piezoelectric layer AlN of through-hole side is equipped with top electrode Ti, through-hole it is another
Back electrode material Ti is equipped in side and through-hole.There is interval between top electrode and back electrode material.Substrate thickness is 430 μm, back of the body electricity
The thickness of pole is 100nm, and the thickness of piezoelectric layer is 1.5 μm, and the thickness of top electrode is 100nm, the back electrode material of piezoelectric layer surface
The thickness of material is 100nm.
The extraction of back electrode in the thin film bulk acoustic wave resonator, including following steps：
(1) it is sequentially depositing (the methods of MOCVD, PLD) back electrode Ti and piezoelectric membrane AlN on a si substrate, obtains AlN/
Ti/Si；
(2) AlN/Ti/Si film cleanings：Acetone 40kHz ultrasound 5min are first used, uses ethyl alcohol, water to clean respectively, removes surface
Organic pollution；Solution (the H now matched with 40 DEG C again2SO4(concentration 98%)：H2O2(concentration 35%)：H2O volume ratios are=1:
3:3) cleaning sample 10min, HF solution (HF (40%)：H2Volume ratio=1 O:10) cleaning sample 10min is eluted with water, removal
The inorganic pollution on surface, drying；
(3) photoetching of through-hole：Pretreated AlN/Ti/Si is put into the inflation of HMDS ovens, forming HMDS on the surfaces AlN increases
Adhesion coating；Spin coating RJZ-304 type positive photoresists, 100 DEG C of baking 100s remove partial moisture；By there is the mask of via hole image
Then version exposes (300-340W exposure powers expose 3-5s)；It is put into TMAH developer solutions and impregnates 60s, finally check figure line
It is wide whether qualified；The piezoelectric membrane after photoetching is passed through 60sccm oxygen plasmas in sense coupling machine again
300s is handled under the power of 80W, removes residue glue；
(4) etching of through-hole：
The piezoelectric membrane for removing residue glue performs etching according to the figure that photoresist is formed to (etching through hole pattern will be integrated and be examined
The smoothness for considering etching, the conflict between damage and high selectivity etching to AlN), setting inductively coupled plasma is carved
Erosion machine technological parameter：The pressure of reaction chamber is 4mTorr, and upper/lower electrode power is respectively 330W/180W, and etching gas is
100sccmCl2/30sccmBCl3, diluent gas Ar flows are 20sccm, and pallet He flows are 4Torr, 0 DEG C of chassis temperature, pressure
Conductive film etches shown in SEM photograph such as Fig. 2 (b) of through-hole, and through-hole diameter is 50 μm；
(5) cleaning before copper plating is steamed：
Evaporation process is very high to the clean level requirement of substrate surface, and out-of-flatness or dirty surface can lead to metal foil
The consequence that film falls off；Need will to etch the AlN/Ti/Si of through-hole before vapor deposition with volume ratio HCl (37%)：H2O=1:1 hydrochloric acid
Solution cleans 10min, bath drying；
(6) AlN/Ti/Si for etching through-hole cleaned is fixed on sample stage and is put into vacuum chamber, thick suction
Reach 10-2Pa, open molecular pump and vacuumize ＜ 10-4Pa, opens electron beam line switch and prepare to start plated film；Wait for crystal oscillator film thickness
After the rate stabilization shown on instrument, baffle is opened, target is bombarded using high-power electron beam, evaporates target metal Ti, make electrode material
Material after vacuum transport to film surface by condensing come electrode evaporation film；The data that observation film thickness gauge is shown therebetween, control beam
Flow power and beam spot position, set evaporation rate asThe consistency and vapor deposition efficiency of counter electrode film, metallic film
Energy spectrum analysis as shown in Figure 3 (Fig. 3 is the energy spectrum diagram in through-hole after electrode evaporation), it can be seen that Ti is inside and outside through-hole, side wall
It is uniformly distributed.
Thin film bulk acoustic wave resonator manufactured in the present embodiment is fixed on fixture and carries out testing impedance.Including with SZT-2A
Four probe resistance instrument carry out resistivity measurement, and carrying out the electric property under different biass with Agilent 4294A impedance analyzers surveys
Electrical performance testing under examination and different frequency sweeps, film resiativity are 47.36k ω/cm.Electrical performance testing under different biass
Reflection is static electric property of the film under continuous current excitation, includes the dielectric constant and loss angle tangent of film, and fixation is swept
It is 10kHz to retouch frequency, and setting bias is scanned from -3V~3V.(Fig. 4 is the inclined piezo-electric of thin film bulk acoustic wave resonator as shown in Figure 4
Hold curve and bias-loss angle tangent curve), the change of Dc bias hardly influences the direct capacitance size of film.C
=1.13pF calculates ε r=3.10 according to capacitance calculation formula C=ε r ε 0*S/d.Although piezoelectric material is in the direct current added outside
Thickness can change under bias, so as to cause the capacitance variations of film.But herein almost without influence, it may be possible to because Si is served as a contrast
The presence at bottom discharges the thickness change of piezoelectric membrane AlN.
What the electrical performance testing under different frequency sweeps reflected is dielectric constant and loss of the film under alternating current excitation
Angle tangent, is the frequency individual features of film, fixed-bias transistor circuit 1V, and scan frequency is from 1-1000kHz.(Fig. 5 is as shown in Figure 5
Frequency-capacitance and frequency-loss angle tangent curve of thin film bulk acoustic wave resonator), dielectric loss is damaged at low frequency by conductance
Consumption is leading.It is increased with the frequency of alternating electric field, starts the case where polarisation hysteresis electrode variation occur, example dielectric characteristic becomes
More meet piezoelectric material.
In the present invention etch when condition be：Set the pressure (7- of sense coupling machine reaction chamber
10mTorr), the flow (50-200sccm) of upper/lower electrode power (50-400W), etching gas and diluent gas, pallet He streams
Measure technological parameters such as (4-8sccm).
The above embodiment is a preferred embodiment of the present invention, but embodiments of the present invention are not by the embodiment
Limitation, it is other it is any without departing from the spirit and principles of the present invention made by changes, modifications, substitutions, combinations, simplifications,
Equivalent substitute mode is should be, is included within the scope of the present invention.
Claims (9)
1. back electrode outbound course in a kind of thin film bulk acoustic wave resonator, it is characterised in that：Include the following steps：
It is set on surface and is sequentially depositing back electrode and piezoelectric membrane on reeded substrate, the groove of back electrode and substrate surface is formed
Then air chamber prepares through-hole on piezoelectric membrane, the lower section of through-hole is back electrode, and top is deposited on the piezoelectric membrane of through-hole side
Electrode, deposition has a back electrode material on the piezoelectric membrane of the through-hole other side and in through-hole, on the piezoelectric membrane of the through-hole other side
And the back electrode material successive sedimentation in through-hole, back electrode are drawn by through-hole, and back electrode is led to the surface of piezoelectric membrane.
2. back electrode outbound course in thin film bulk acoustic wave resonator according to claim 1, it is characterised in that：The top electrode
There is interval with back electrode material.
3. back electrode outbound course in thin film bulk acoustic wave resonator according to claim 1, it is characterised in that：
The through-hole refers to the photoetching that via hole image is first carried out to piezoelectric membrane, is then formed by etching.
4. back electrode outbound course in thin film bulk acoustic wave resonator according to claim 1, it is characterised in that：Specifically include with
Lower step：
(1) it is set on surface and is sequentially depositing back electrode and piezoelectric membrane on reeded substrate, obtain piezoelectric membrane/back electrode/lining
Bottom；
(2) piezoelectric membrane/back electrode/substrate is pre-processed, the impurity on removal piezoelectric membrane surface；
(3) pretreated piezoelectric membrane will be passed through and carries out photoetching, and etched, through-hole is obtained on piezoelectric membrane；The photoetching of the photoetching
Glue is positive photoresist；
(4) piezoelectric membrane/back electrode/substrate for being etched with through-hole is cleaned, removes impurity；Then in the pressure of through-hole side
Top electrode material is deposited by electron beam evaporation deposition method on conductive film, in through-holes and on the piezoelectric membrane of the through-hole other side
Back electrode material is deposited by electron beam evaporation deposition method, back electrode leads to the surface of piezoelectric membrane by through-hole.
5. back electrode outbound course in thin film bulk acoustic wave resonator according to claim 4, it is characterised in that：Step (3)
The specific steps are：
Piezoelectric membrane surface vapor at counterdie, spin coating positive photoresist is dry, by there is the progress of the mask plate of via hole image
Exposure, developer solution impregnate, are performed etching according to the figure of through-hole, obtain through-hole.
6. back electrode outbound course in thin film bulk acoustic wave resonator according to claim 5, it is characterised in that：The condition of exposure
For 300-340W exposure powers, 3-5s is exposed；Developer solution soaking time is 40-60s.
7. back electrode outbound course in thin film bulk acoustic wave resonator according to claim 4, it is characterised in that：In step (1)
Pretreatment refers to being ultrasonically treated with acetone, is then cleaned successively with ethyl alcohol, water, then with by H2SO4、H2O2With H2What O was formulated
Solution is impregnated, then is impregnated with HF solution, is eluted with water, and is dried.
8. back electrode outbound course in thin film bulk acoustic wave resonator according to claim 4, it is characterised in that：In step (4)
The cleaning refers to using salt acid soak, is eluted with water.
9. a kind of thin film bulk acoustic wave resonator obtained by any one of claim 1~8 the method, it is characterised in that：Including
Substrate, back electrode and piezoelectric layer are disposed on the substrate, and the surface of the substrate is equipped with groove, back electrode and substrate table
The groove in face forms air chamber, and the piezoelectric layer is equipped with through-hole, and the lower section of through-hole is back electrode, is set on the piezoelectric layer of through-hole side
There is top electrode, back electrode material is equipped in the other side of through-hole and through-hole；There is interval between top electrode and back electrode material.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111628749A (en) * | 2020-05-06 | 2020-09-04 | 河源市众拓光电科技有限公司 | Frequency-adjustable film bulk acoustic resonator |
| CN112234949A (en) * | 2020-10-29 | 2021-01-15 | 武汉大学 | Three-dimensional bulk acoustic wave resonator with tunable multiple frequency bands |
| WO2021036758A1 (en) * | 2019-08-30 | 2021-03-04 | 迈感微电子(上海)有限公司 | Bulk acoustic wave resonator |
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| CN101465628A (en) * | 2009-01-15 | 2009-06-24 | 电子科技大学 | Film bulk acoustic resonator and preparation method thereof |
| CN103873010A (en) * | 2014-03-17 | 2014-06-18 | 电子科技大学 | Piezoelectric film bulk acoustic resonator and preparation method thereof |
| CN104038177A (en) * | 2014-06-04 | 2014-09-10 | 江苏艾伦摩尔微电子科技有限公司 | Thin film bulk acoustic resonator for ultraviolet detection and preparation method thereof |
| CN205940822U (en) * | 2016-05-06 | 2017-02-08 | 中国工程物理研究院电子工程研究所 | Bulk acoustic wave wall shear stress sensor |
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| CN101465628A (en) * | 2009-01-15 | 2009-06-24 | 电子科技大学 | Film bulk acoustic resonator and preparation method thereof |
| CN103873010A (en) * | 2014-03-17 | 2014-06-18 | 电子科技大学 | Piezoelectric film bulk acoustic resonator and preparation method thereof |
| CN104038177A (en) * | 2014-06-04 | 2014-09-10 | 江苏艾伦摩尔微电子科技有限公司 | Thin film bulk acoustic resonator for ultraviolet detection and preparation method thereof |
| CN205940822U (en) * | 2016-05-06 | 2017-02-08 | 中国工程物理研究院电子工程研究所 | Bulk acoustic wave wall shear stress sensor |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2021036758A1 (en) * | 2019-08-30 | 2021-03-04 | 迈感微电子(上海)有限公司 | Bulk acoustic wave resonator |
| CN111628749A (en) * | 2020-05-06 | 2020-09-04 | 河源市众拓光电科技有限公司 | Frequency-adjustable film bulk acoustic resonator |
| CN112234949A (en) * | 2020-10-29 | 2021-01-15 | 武汉大学 | Three-dimensional bulk acoustic wave resonator with tunable multiple frequency bands |
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