CN111697937A - Film bulk acoustic resonator and preparation method thereof - Google Patents
Film bulk acoustic resonator and preparation method thereof Download PDFInfo
- Publication number
- CN111697937A CN111697937A CN202010374020.0A CN202010374020A CN111697937A CN 111697937 A CN111697937 A CN 111697937A CN 202010374020 A CN202010374020 A CN 202010374020A CN 111697937 A CN111697937 A CN 111697937A
- Authority
- CN
- China
- Prior art keywords
- layer
- top electrode
- electrode
- bottom electrode
- film
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000002360 preparation method Methods 0.000 title abstract description 5
- 239000000758 substrate Substances 0.000 claims abstract description 62
- 238000012546 transfer Methods 0.000 claims abstract description 46
- 239000010408 film Substances 0.000 claims description 95
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 24
- 238000000034 method Methods 0.000 claims description 20
- 239000010409 thin film Substances 0.000 claims description 17
- 238000005530 etching Methods 0.000 claims description 14
- 238000004519 manufacturing process Methods 0.000 claims description 14
- 235000012239 silicon dioxide Nutrition 0.000 claims description 12
- 239000000377 silicon dioxide Substances 0.000 claims description 12
- 230000000694 effects Effects 0.000 claims description 10
- 229910052751 metal Inorganic materials 0.000 claims description 9
- 239000002184 metal Substances 0.000 claims description 9
- 230000004913 activation Effects 0.000 claims description 7
- 230000005674 electromagnetic induction Effects 0.000 claims description 7
- 238000009616 inductively coupled plasma Methods 0.000 claims description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 4
- 239000013078 crystal Substances 0.000 claims description 4
- 238000005240 physical vapour deposition Methods 0.000 claims description 4
- 238000004549 pulsed laser deposition Methods 0.000 claims description 4
- 229910052710 silicon Inorganic materials 0.000 claims description 4
- 239000010703 silicon Substances 0.000 claims description 4
- 238000003486 chemical etching Methods 0.000 claims description 3
- 238000005229 chemical vapour deposition Methods 0.000 claims description 3
- 238000000151 deposition Methods 0.000 claims description 3
- 229910052737 gold Inorganic materials 0.000 claims description 3
- 229910052750 molybdenum Inorganic materials 0.000 claims description 3
- 229910021421 monocrystalline silicon Inorganic materials 0.000 claims description 3
- 229910052697 platinum Inorganic materials 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- 229910052719 titanium Inorganic materials 0.000 claims description 3
- 229910052721 tungsten Inorganic materials 0.000 claims description 3
- 238000007517 polishing process Methods 0.000 claims description 2
- 230000003071 parasitic effect Effects 0.000 abstract description 12
- 239000010410 layer Substances 0.000 description 129
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 8
- 238000004891 communication Methods 0.000 description 5
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 description 5
- HFGPZNIAWCZYJU-UHFFFAOYSA-N lead zirconate titanate Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ti+4].[Zr+4].[Pb+2] HFGPZNIAWCZYJU-UHFFFAOYSA-N 0.000 description 4
- 229910052451 lead zirconate titanate Inorganic materials 0.000 description 4
- 238000000623 plasma-assisted chemical vapour deposition Methods 0.000 description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- 239000011787 zinc oxide Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 239000010931 gold Substances 0.000 description 3
- 238000010897 surface acoustic wave method Methods 0.000 description 3
- 239000010936 titanium Substances 0.000 description 3
- 239000008358 core component Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000001755 magnetron sputter deposition Methods 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Images
Classifications
-
- 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
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/25—Constructional features of resonators using surface acoustic waves
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/64—Filters using surface acoustic waves
Abstract
The invention discloses a film bulk acoustic resonator, which comprises a transfer substrate, a bonding layer, a filling and leveling layer, a bottom electrode, a piezoelectric film and a top electrode, which are sequentially distributed from bottom to top; forming a sandwich structure by the piezoelectric film, the bottom electrode and the first layer of the top electrode, and forming a groove on the transfer substrate to form an air cavity among the bottom electrode, the bonding layer and the transfer substrate; the bulk acoustic wave generated by the piezoelectric film can be totally reflected on the surface of the bottom electrode through the air cavity, so that the bulk acoustic wave is limited between the first layer of the top electrode and the bottom electrode, and the function of a resonator is realized; meanwhile, the top electrode second layer and the top electrode third layer are arranged on the top electrode first layer and are respectively used for optimizing the series resonance point and the parallel resonance point of the film acoustic wave resonator, the parasitic effect is eliminated, and the quality factor is improved. The invention also discloses a preparation method of the film bulk acoustic resonator.
Description
Technical Field
The invention relates to an acoustic wave resonator, in particular to a film bulk acoustic wave resonator and a preparation method thereof.
Background
With the development of modern wireless communication technology towards high frequency and high speed, higher requirements are raised on a front-end filter commonly used for radio frequency communication. While the working frequency is continuously improved, the device volume, the use performance, the stability and the integration are also required to be higher, and the Surface Acoustic Wave (SAW) filter used in the past cannot meet the requirement of high-frequency communication due to the problems of larger volume, compatible process, working frequency band and the like.
The Film Bulk Acoustic Resonator (FBAR) is a novel filter, and compared with a surface Acoustic wave filter, the FBAR not only has the characteristics of small volume, large power capacity, inheritability, high working frequency band and the like, but also has better out-of-band rejection and insertion loss, and is widely used in the current 5G communication.
Generally, the structure of a film bulk acoustic resonator mainly comprises a diaphragm type, an air gap type and a solid assembly type, which are all sandwich structures of 'electrode-piezoelectric film-electrode', and the principle is that the piezoelectric property of a piezoelectric film is utilized, when alternating voltage is applied to electrodes, the piezoelectric effect converts electric energy into mechanical energy, so that the piezoelectric film is mechanically deformed, and bulk acoustic waves are excited in the piezoelectric film; when the boost wave is transmitted to the surfaces of the piezoelectric film and the electrodes, the sound wave is reflected back under the action of the common acoustic layer outside the electrodes, so that the bulk sound wave is limited between the two electrodes. Therefore, in order to reduce the loss of the acoustic wave, the bulk acoustic wave is totally reflected as much as possible. The acoustic impedance of the air can be considered to be approximately zero, so that the surfaces of the top electrode and the bottom electrode are required to be in contact with the air during manufacturing, and because the top electrode is in contact with the air and the bottom electrode grows on the substrate, the surface of the bottom electrode is difficult to be in contact with the air during the manufacturing process, and meanwhile, the mechanical strength is ensured without influencing the structure of the film acoustic wave resonator.
In addition, in the production process of the film bulk acoustic resonator, due to the existence of parasitic effect, parasitic capacitance can be generated and damage is caused to the core component of the film bulk acoustic resonator in the production process flow, so that the quality factor of the produced film bulk acoustic resonator is low; meanwhile, parasitic capacitance is remained in the film bulk acoustic resonator, so that great energy damage is often caused when the film bulk acoustic resonator is used in a subsequent integrated circuit. In order to improve the above-mentioned problems of the mainstream process, in the prior art, only a tuning layer is generally added on the top electrode to reduce the parasitic capacitance, thereby improving the quality factor. However, parasitic capacitance still exists in the production process, and meanwhile, the optimization effect of the structure of the single-layer adjusting layer on the series resonance point is obvious, but the optimization on the parallel resonance point is not obvious, and the quality factor cannot be well improved.
Disclosure of Invention
In order to overcome the defects of the prior art, an object of the present invention is to provide a thin film acoustic resonator, which can solve the problems of complex structure, instability, etc. of the thin film bulk acoustic resonator in the prior art.
The second objective of the present invention is to provide a method for manufacturing a film bulk acoustic resonator, which can solve the problem of low quality factor in the prior art of the manufacturing process of the film bulk acoustic resonator.
One of the purposes of the invention is realized by adopting the following technical scheme:
a film bulk acoustic resonator comprises a transfer substrate, a bonding layer, a filling layer, a bottom electrode, a piezoelectric film and a top electrode which are sequentially distributed from bottom to top; the top electrode comprises a top electrode first layer, a top electrode second layer and a top electrode third layer which are sequentially distributed from bottom to top;
the piezoelectric film is positioned between the bottom electrode and the first layer of the top electrode, so that a sandwich structure is formed among the first layer of the top electrode, the piezoelectric film and the bottom electrode, and meanwhile, the first layer of the top electrode and the bottom electrode are arranged in an up-down opposite mode;
the transfer substrate comprises a groove positioned in the middle of the transfer substrate and an annular protrusion arranged around the groove; the bonding layer is positioned above the annular protrusion; the filling and leveling layer is arranged above the bonding layer and surrounds the bottom electrode, so that an air cavity is formed among the bottom electrode, the bonding layer and the transfer substrate; when the top electrode of the film acoustic wave resonator is electrified, the piezoelectric film deforms and excites a bulk acoustic wave, and when the bulk acoustic wave is transmitted between the piezoelectric film and the bottom electrode, the bulk acoustic wave is totally reflected on the surface of the bottom electrode due to the existence of the air cavity and is limited between the first layer of the top electrode and the bottom electrode;
optimizing the series resonance point of the film acoustic wave resonator through the electromagnetic induction effect of the second layer of the top electrode, so that the ripple at the series resonance point is smooth and the clutter is suppressed; and optimizing the parallel resonance point of the film acoustic wave resonator by the electromagnetic induction effect of the third layer of the top electrode, so that the ripple at the parallel resonance point is smooth and the clutter is suppressed.
Further, the transfer substrate is composed of single-crystal high-resistance silicon; the bonding layer is composed of silicon dioxide.
Further, the depth of the groove of the transfer substrate is 500 nm-3 um; the thickness of the bonding layer is 400 nm-5 um; the depth of the air cavity is 900 nm-8 um.
Further, the piezoelectric thin film is composed of one or more of AIN, ZNO and PZT; the thickness of the piezoelectric film is 200 nm-3 um. .
Furthermore, the bottom electrode and the top electrode are both metal electrodes; the metal electrode is composed of one or more of Pt, Mo, W, Ti and Au; the thickness of the bottom electrode is 50 nm-500 nm.
Further, the thickness of the first layer of the top electrode is 50 nm-500 nm, the thickness of the second layer of the top electrode is 150 nm-400 nm, and the thickness of the third layer of the top electrode is 150 nm-400 nm.
The second purpose of the invention is realized by adopting the following technical scheme:
a method for manufacturing a thin film bulk acoustic resonator employed as one of the objects of the present invention, the method comprising:
selecting a monocrystalline silicon wafer as an epitaxial substrate, and growing a piezoelectric film on the epitaxial substrate;
growing a bottom electrode on the first surface of the piezoelectric film, and obtaining the shape of the bottom electrode by an etching method;
growing a layer of silicon dioxide on the first surface of the piezoelectric film and the bottom electrode to be used as a filling and leveling layer, removing a part covering the bottom electrode by adopting an etching method, and simultaneously ensuring that the thickness of the filling and leveling layer is the same as that of the bottom electrode to generate a first wafer;
selecting a transfer substrate and etching a groove in the middle of the transfer substrate to form an annular protrusion on the periphery of the transfer substrate, growing a layer of silicon dioxide on the annular protrusion to serve as a bonding layer, and performing activation treatment on the surface of the bonding layer to generate a second wafer;
step (5) aligning and bonding the bonding layer of the second wafer and the leveling layer of the first wafer, fixing the first wafer above the second wafer, and transferring the piezoelectric film to form an air cavity among the bonding layer, the bottom electrode and the transfer substrate;
step (6) separating the epitaxial substrate from the piezoelectric film;
step (7) depositing a top electrode first layer, a top electrode second layer and a top electrode third layer on the second surface of the piezoelectric film in sequence, and enabling the top electrode first layer and the bottom electrode to be arranged in an up-down opposite mode; and meanwhile, the first layer of the top electrode, the piezoelectric film and the bottom electrode are ensured to form a sandwich structure.
Further, the step (1) includes generating a piezoelectric film on the epitaxial substrate by any one of physical vapor deposition, metal organic chemical vapor deposition, and pulsed laser deposition.
Further, the step (4) includes: forming a groove by placing the transfer substrate in an inductively coupled plasma etcher device for etching; and carrying out surface activation treatment on the bonding layer by placing the transfer substrate in an inductively coupled plasma etching machine.
Further, the step (6) includes: the epitaxial substrate is separated from the piezoelectric thin film by any one or more of a mechanical thinning process, a chemical polishing process, and a chemical etching process.
Compared with the prior art, the invention has the beneficial effects that:
according to the invention, a resonator is formed by a structure of three layers of top electrodes, a first layer of the top electrode, a piezoelectric film and a bottom electrode; the series resonance point of the film acoustic wave resonator is optimized, the ripple at the series resonance point is smooth, the clutter is suppressed, the parallel resonance point of the film acoustic wave resonator is optimized, the ripple at the parallel resonance point is smooth, and the clutter is suppressed by the top electrode second layer and the top electrode third layer through the electromagnetic induction effect of the top electrode second layer and the top electrode third layer, so that the parasitic effect is reduced, and the quality factor of the film acoustic wave resonator is improved.
Drawings
Fig. 1 is a schematic structural diagram of a vertical section of a thin film acoustic resonator provided by the present invention;
FIG. 2 is a schematic diagram of a cross-section of the bottom electrode of FIG. 1;
fig. 3 is a schematic diagram of a cross-section of the top electrode of fig. 1.
In the figure: 101. transferring the substrate; 102. a bonding layer; 103. filling and leveling the layer; 104. a bottom electrode; 105. a piezoelectric film; 200. a top electrode; 201. a top electrode first layer; 202. a top electrode second layer; 203. a top electrode third layer.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and the detailed description, and it should be noted that any combination of the embodiments or technical features described below can be used to form a new embodiment without conflict.
Example one
The invention provides a preferable embodiment, and the film bulk acoustic resonator has a simple and stable structure, has small damage to a core component of the film bulk acoustic resonator in the manufacturing process, can avoid the introduction of parasitic capacitance, greatly improves the quality factor of the film bulk acoustic resonator, and reduces the manufacturing cost of the film bulk acoustic resonator.
As shown in fig. 1, a film bulk acoustic resonator includes a transfer substrate 101, a bonding layer 102, a leveling layer 103, a bottom electrode 104, a piezoelectric film 105, and a top electrode 200, which are sequentially disposed from bottom to top.
The top electrode 200 is located above the piezoelectric film 105, and the bottom electrode 104 is located below the piezoelectric film 105. Thus, a sandwich structure is formed among the top electrode 200, the piezoelectric film 105, and the bottom electrode 104.
The transfer substrate 101 is a ring structure including a groove located in the middle of the transfer substrate 101 and a ring-shaped protrusion located at the periphery of the transfer substrate 101.
The bonding layer 102 is located above the annular protrusion at the periphery of the transfer substrate 101. The fill layer 103 is disposed above the bonding layer 102 and surrounds the bottom electrode 104. The bottom electrode 104 is fixed above the groove in the middle of the transfer substrate 101 by the fill-level layer 103. Thus, air cavities are formed between the bonding layer 102, the bottom electrode 104 and the transfer substrate 101.
When the film acoustic wave resonator works: when an ac voltage is applied to the top electrode 200, the piezoelectric effect converts the electrical energy into mechanical energy, which mechanically deforms the piezoelectric film 105 to excite bulk acoustic waves in the piezoelectric film 105. When the bulk acoustic wave is transmitted to the bottom electrode 104 through the piezoelectric film 105, the bulk acoustic wave can be totally reflected on the surface of the bottom electrode 104 by the action principle of the acoustic layer due to the existence of the lower air cavity of the bottom electrode 104, and then is limited between the top electrode 200 and the bottom electrode 104, thereby ensuring the work of the film bulk acoustic wave resonator.
The filling layer 103 is arranged around the bottom electrode 104 for one circle, so that the mechanical strength of the bottom electrode 104 can be ensured, and the thin film acoustic resonator can be prevented from being damaged due to the fact that the bottom electrode 104 collapses downwards due to the deformation of the piezoelectric film 105.
Preferably, in order to eliminate the parasitic effect, the top electrode 200 of the present invention includes a top electrode first layer 201, a top electrode second layer 202, and a top electrode third layer 203, which are sequentially distributed from bottom to top. The top electrode first layer 201, the piezoelectric film 105 and the bottom electrode 104 form a sandwich structure to form a main body structure of the film acoustic wave resonator.
The series resonance point of the film acoustic wave resonator is optimized by arranging the top electrode second layer 202 and by means of the electromagnetic induction effect of the top electrode second layer 202, so that the ripple at the series resonance point is smooth, and the clutter is suppressed; the parallel resonance point of the film acoustic wave resonator is optimized by arranging the top electrode third layer 203 and by means of the electromagnetic induction effect of the top electrode third layer 203, so that ripples at the parallel resonance point are smooth, and clutter is suppressed. That is, the present invention achieves the clutter suppression effect on the series and parallel resonance through the top electrode second layer 202 and the top electrode third layer 203. The clutter is embodied by stray parasitic capacitance, namely the clutter is caused by parasitic effect; therefore, by suppressing the clutter, the power loss generated by the clutter in the work is reduced, the parasitic effect is reduced, and the quality factor is improved.
Preferably, the top electrode first layer 201 is disposed opposite to the bottom electrode 104. That is, when the top electrode first layer 201 is located on the upper layer of the piezoelectric film 105, the top electrode first layer 201 is disposed opposite to the bottom electrode 104 disposed under the piezoelectric film 105.
Preferably, the top electrode second layer 202 and the top electrode third layer 203 are both of an annular structure, and are sequentially located above the top electrode first layer 201 from bottom to top.
Preferably, as shown in fig. 2, the cross-section of the bottom electrode 104 has a pentagonal shape. That is, the bottom electrode 104 is a truncated cone structure with a pentagonal cross section.
As shown in fig. 3, the cross section of the top electrode first layer 201 is in a pentagonal structure, that is, the top electrode first layer 201 is in a solid truncated cone structure. The cross sections of the top electrode second layer 202 and the top electrode third layer 203 are both in annular pentagonal structures, and the top electrode second layer 202 and the top electrode third layer 203 are both in hollow annular truncated cone structures. Wherein the area of the cross-section of the top electrode first layer 201 is larger than the area of the cross-section of the bottom electrode 104. Because the high frequency signal can greatly increase its loss when transmitting between the parallel limit, and the no limit of pentagon is not parallel each other, consequently when all adopting pentagon structure with bottom electrode 104, top electrode, reducible high frequency signal is at the loss of parallel limit transmission.
Further, the area and the perimeter of the cross section of the second layer 202 of the top electrode satisfy a predetermined ratio, and similarly, the area and the perimeter of the cross section of the third layer 203 of the top electrode also satisfy a predetermined ratio. Preferably, the preset proportion is 50-100.
That is, the top electrode first layer 201, the top electrode second layer 202, and the top electrode third layer 203 all have different cross-sectional areas. Preferably, the area of the first layer 201 of the top electrode is 2500 μm 2-90000 μm 2. The area of the top electrode second layer 202 is 4 μm 2-400 μm 2. The area of the third layer 203 of the top electrode is 0.25 μm 2-100 μm 2.
Further, the thickness of the top electrode first layer 201 is 50nm to 500nm, the thickness of the top electrode second layer 202 is 150nm to 400nm, and the thickness of the top electrode third layer 203 is 150nm to 400 nm.
Preferably, the top electrode first layer 201 has a thickness of 300nm, and the top electrode second layer 202 and the top electrode third layer 203 each have a thickness of 150 nm.
Further, the transfer substrate 101 is composed of single-crystal high-resistance silicon. That is, the transfer substrate is a single-crystal high-resistance silicon layer. Wherein, the depth of the groove on the transfer substrate 101 is 500 nm-3 um.
Further, the bonding layer 102 is made of silicon dioxide, and the thickness thereof is 400nm to 5 um. That is, the bonding layer is a silicon dioxide layer. Preferably, the bonding layer 102 has a thickness of 800 nm.
In addition, the depth of the air cavity formed between the bonding layer 102, the bottom electrode 104 and the transfer substrate 101 is 900nm to 8 um.
Further, the piezoelectric thin film 105 is composed of one or more of AIN (aluminum nitride), ZNO (zinc oxide), and PZT (lead zirconate titanate). That is, the piezoelectric thin film may be aluminum nitride, zinc oxide, lead zirconate titanate, or the like, or may be a mixture of any two or three of the above. Wherein, the thickness of the piezoelectric film 105 is 200 nm-3 um. Preferably, the thickness of the piezoelectric film 105 is 1.2 um. For example, AIN is a material having good comprehensive properties in the aspects of heat, electricity, light, machinery and the like, and has wide application as an electronic thin film material in the fields of microelectronics, electronic elements, high-frequency broadband communication, power semiconductor devices and the like.
Further, the bottom electrode 104 and the top electrode 200 are both metal electrodes. Wherein the metal electrode is composed of one or more of Pt (platinum), Mo (molybdenum), W (tungsten), Ti (titanium) and Au (gold). The thickness of the bottom electrode 104 is 50nm to 500 nm. Preferably, the thickness of the bottom electrode 104 is 300 nm.
The series resonance point of the resonator is optimized through the top electrode second layer 202; the parallel resonance point of the resonator is optimized through the top electrode third layer 203, so that the quality factor of the resonator is greatly improved, and the performance is improved.
Example two
Based on the first embodiment, the invention also provides a preparation method of the film acoustic wave resonator, which specifically comprises the following steps:
and step S1, selecting a monocrystalline silicon wafer as an epitaxial substrate, and growing a piezoelectric film on the epitaxial substrate.
Preferably, the piezoelectric film is grown on the epitaxial substrate by using any one or more of Physical Vapor Deposition (PVD), Metal Organic Chemical Vapor Deposition (MOCVD), and Pulsed Laser Deposition (PLD).
Step S2 is to grow a bottom electrode on the first surface of the piezoelectric film and to obtain the shape of the bottom electrode by an etching method.
Preferably, the bottom electrode is generated on the first surface of the piezoelectric film by a magnetron sputtering method.
Step S3, growing a layer of silicon dioxide on the first surface of the piezoelectric film and the bottom electrode as a filling layer, and removing a portion covering the bottom electrode by etching while ensuring that the filling layer and the bottom electrode have the same thickness, thereby forming a first wafer.
Preferably, the method for forming a silicon dioxide layer on the bottom electrode is a Plasma Enhanced Chemical Vapor Deposition (PECVD) method.
And step S4, selecting a transfer substrate and etching a groove in the middle of the transfer substrate, so that an annular protrusion is formed on the periphery of the transfer substrate, a layer of silicon dioxide is grown on the annular protrusion to serve as a bonding layer, and meanwhile, the surface of the bonding layer is subjected to activation treatment, and a second wafer is generated.
Preferably, when forming the groove on the transfer substrate, the transfer substrate is etched and the groove is formed in an inductively coupled plasma etcher (ICP-RIE) apparatus.
A layer of silicon dioxide is grown on the annular protrusion at the periphery of the transfer substrate using Plasma Enhanced Chemical Vapor Deposition (PECVD) and serves as a second bonding layer.
And when the surface of the bonding layer is subjected to activation treatment, carrying out surface activation treatment on the bonding layer in an inductively coupled plasma etching machine.
Step S5, aligning the bonding layer of the second wafer and the leveling layer of the first wafer, and then sending the aligned bonding layer of the second wafer and the leveling layer of the first wafer into a bonding machine for bonding, so that firm bonding is formed between the second wafer and the first wafer, and the first wafer is located above the second wafer; and meanwhile, the piezoelectric film transfer is realized, so that an air cavity is formed among the bonding layer, the bottom electrode and the transfer substrate.
And step S6, separating the epitaxial substrate from the piezoelectric film. Preferably, the epitaxial substrate is separated from the piezoelectric film by mechanical thinning, chemical polishing and chemical etching.
Step S7, depositing a top electrode first layer, a top electrode second layer and a top electrode third layer on the second surface of the piezoelectric film in sequence, and enabling the top electrode first layer and the bottom electrode to be arranged in an up-down opposite mode; meanwhile, the first layer of the top electrode, the piezoelectric film and the bottom electrode are ensured to form a sandwich structure; wherein the first layer is the same as the bottom electrode in shape; the second layer and the third layer are ring-shaped structures with the same shape as the first layer.
Preferably, when the top electrode is opposed to the bottom electrode, the top electrode is opposed to the bottom electrode by performing an imaging process with the apparatus.
The above embodiments are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby, and any insubstantial changes and substitutions made by those skilled in the art based on the present invention are within the protection scope of the present invention.
Claims (10)
1. The film bulk acoustic resonator is characterized by comprising a transfer substrate, a bonding layer, a filling layer, a bottom electrode, a piezoelectric film and a top electrode which are sequentially distributed from bottom to top; the top electrode comprises a top electrode first layer, a top electrode second layer and a top electrode third layer which are sequentially distributed from bottom to top;
the piezoelectric film is positioned between the bottom electrode and the first layer of the top electrode, so that a sandwich structure is formed among the first layer of the top electrode, the piezoelectric film and the bottom electrode, and meanwhile, the first layer of the top electrode and the bottom electrode are arranged in an up-down opposite mode;
the transfer substrate comprises a groove positioned in the middle of the transfer substrate and an annular protrusion arranged around the groove; the bonding layer is positioned above the annular protrusion; the filling and leveling layer is arranged above the bonding layer and surrounds the bottom electrode, so that an air cavity is formed among the bottom electrode, the bonding layer and the transfer substrate; when the top electrode of the film acoustic wave resonator is electrified, the piezoelectric film deforms and excites a bulk acoustic wave, and when the bulk acoustic wave is transmitted between the piezoelectric film and the bottom electrode, the bulk acoustic wave is totally reflected on the surface of the bottom electrode due to the existence of the air cavity and is limited between the first layer of the top electrode and the bottom electrode;
optimizing the series resonance point of the film acoustic wave resonator through the electromagnetic induction effect of the second layer of the top electrode, so that the ripple at the series resonance point is smooth and the clutter is suppressed; and optimizing the parallel resonance point of the film acoustic wave resonator by the electromagnetic induction effect of the third layer of the top electrode, so that the ripple at the parallel resonance point is smooth and the clutter is suppressed.
2. The thin film bulk acoustic resonator of claim 1, wherein the transfer substrate is composed of single crystal high resistivity silicon; the bonding layer is composed of silicon dioxide.
3. The film bulk acoustic resonator according to claim 1, wherein the depth of the groove of the transfer substrate is 500nm to 3 um; the thickness of the bonding layer is 400 nm-5 um; the depth of the air cavity is 900 nm-8 um.
4. The thin film bulk acoustic resonator of claim 1, wherein the piezoelectric thin film is composed of one or more of AIN, ZNO, and PZT; the thickness of the piezoelectric film is 200 nm-3 um.
5. The film bulk acoustic resonator of claim 1, wherein the bottom electrode and the top electrode are both metal electrodes; the metal electrode is composed of one or more of Pt, Mo, W, Ti and Au; the thickness of the bottom electrode is 50 nm-500 nm.
6. The film bulk acoustic resonator of claim 1, wherein the thickness of the first layer of the top electrode is 50nm to 500nm, the thickness of the second layer of the top electrode is 150nm to 400nm, and the thickness of the third layer of the top electrode is 150nm to 400 nm.
7. A method of manufacturing a thin film bulk acoustic resonator according to any of claims 1 to 6, comprising:
selecting a monocrystalline silicon wafer as an epitaxial substrate, and growing a piezoelectric film on the epitaxial substrate;
growing a bottom electrode on the first surface of the piezoelectric film, and obtaining the shape of the bottom electrode by an etching method;
growing a layer of silicon dioxide on the first surface of the piezoelectric film and the bottom electrode to be used as a filling and leveling layer, removing a part covering the bottom electrode by adopting an etching method, and simultaneously ensuring that the thickness of the filling and leveling layer is the same as that of the bottom electrode to generate a first wafer;
selecting a transfer substrate and etching a groove in the middle of the transfer substrate to form an annular protrusion on the periphery of the transfer substrate, growing a layer of silicon dioxide on the annular protrusion to serve as a bonding layer, and performing activation treatment on the surface of the bonding layer to generate a second wafer;
step (5) aligning and bonding the bonding layer of the second wafer and the leveling layer of the first wafer, fixing the first wafer above the second wafer, and transferring the piezoelectric film to form an air cavity among the bonding layer, the bottom electrode and the transfer substrate;
step (6) separating the epitaxial substrate from the piezoelectric film;
step (7) depositing a top electrode first layer, a top electrode second layer and a top electrode third layer on the second surface of the piezoelectric film in sequence, and enabling the top electrode first layer and the bottom electrode to be arranged in an up-down opposite mode; and meanwhile, the first layer of the top electrode, the piezoelectric film and the bottom electrode are ensured to form a sandwich structure.
8. The method for manufacturing a film bulk acoustic resonator according to claim 7, wherein the step (1) comprises forming a piezoelectric film on an epitaxial substrate by any one of physical vapor deposition, metal organic chemical vapor deposition, and pulsed laser deposition.
9. The method for manufacturing a thin film bulk acoustic resonator according to claim 7, wherein the step (4) comprises: forming a groove by placing the transfer substrate in an inductively coupled plasma etcher device for etching; and carrying out surface activation treatment on the bonding layer by placing the transfer substrate in an inductively coupled plasma etching machine.
10. The method of manufacturing a thin film bulk acoustic wave resonator according to claim 7, wherein the step (6) includes: the epitaxial substrate is separated from the piezoelectric thin film by any one or more of a mechanical thinning process, a chemical polishing process, and a chemical etching process.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010374020.0A CN111697937A (en) | 2020-05-06 | 2020-05-06 | Film bulk acoustic resonator and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010374020.0A CN111697937A (en) | 2020-05-06 | 2020-05-06 | Film bulk acoustic resonator and preparation method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111697937A true CN111697937A (en) | 2020-09-22 |
Family
ID=72477081
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010374020.0A Pending CN111697937A (en) | 2020-05-06 | 2020-05-06 | Film bulk acoustic resonator and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111697937A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113965183A (en) * | 2021-12-23 | 2022-01-21 | 深圳新声半导体有限公司 | Film bulk acoustic resonator with multiple top electrode shapes |
| WO2023125757A1 (en) * | 2021-12-31 | 2023-07-06 | 河源市艾佛光通科技有限公司 | High-bandwidth cavity type film bulk acoustic resonator and preparation method therefor |
| WO2023143005A1 (en) * | 2022-01-27 | 2023-08-03 | 河源市艾佛光通科技有限公司 | High-bandwidth silicon back face etching type film bulk acoustic resonator, and preparation method therefor |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130063227A1 (en) * | 2011-09-14 | 2013-03-14 | Avago Technologies Wireless IP (Singapore) Pte, Ltd | Accoustic resonator having multiple lateral features |
| US20140354115A1 (en) * | 2011-09-14 | 2014-12-04 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Solidly mounted acoustic resonator having multiple lateral features |
| CN110474616A (en) * | 2019-08-29 | 2019-11-19 | 华南理工大学 | A kind of air-gap type thin film bulk acoustic wave resonator and preparation method thereof |
| CN111082771A (en) * | 2019-12-26 | 2020-04-28 | 河源市众拓光电科技有限公司 | Bulk acoustic wave resonator, preparation method thereof and filter |
-
2020
- 2020-05-06 CN CN202010374020.0A patent/CN111697937A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130063227A1 (en) * | 2011-09-14 | 2013-03-14 | Avago Technologies Wireless IP (Singapore) Pte, Ltd | Accoustic resonator having multiple lateral features |
| CN103001602A (en) * | 2011-09-14 | 2013-03-27 | 安华高科技无线Ip（新加坡）私人有限公司 | Accoustic resonator having multiple lateral features |
| US20140354115A1 (en) * | 2011-09-14 | 2014-12-04 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Solidly mounted acoustic resonator having multiple lateral features |
| CN110474616A (en) * | 2019-08-29 | 2019-11-19 | 华南理工大学 | A kind of air-gap type thin film bulk acoustic wave resonator and preparation method thereof |
| CN111082771A (en) * | 2019-12-26 | 2020-04-28 | 河源市众拓光电科技有限公司 | Bulk acoustic wave resonator, preparation method thereof and filter |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113965183A (en) * | 2021-12-23 | 2022-01-21 | 深圳新声半导体有限公司 | Film bulk acoustic resonator with multiple top electrode shapes |
| CN113965183B (en) * | 2021-12-23 | 2022-03-15 | 深圳新声半导体有限公司 | Film bulk acoustic resonator with multiple top electrode shapes |
| WO2023125757A1 (en) * | 2021-12-31 | 2023-07-06 | 河源市艾佛光通科技有限公司 | High-bandwidth cavity type film bulk acoustic resonator and preparation method therefor |
| WO2023143005A1 (en) * | 2022-01-27 | 2023-08-03 | 河源市艾佛光通科技有限公司 | High-bandwidth silicon back face etching type film bulk acoustic resonator, and preparation method therefor |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111697937A (en) | Film bulk acoustic resonator and preparation method thereof | |
| EP4087130A1 (en) | Bulk acoustic resonator with bottom electrode as gap electrode, and filter and electronic device | |
| KR100737088B1 (en) | Acoustic resonator | |
| KR100799391B1 (en) | Thin film acoustic resonator and method of manufacturing the resonator | |
| CN111245397A (en) | Bulk acoustic wave resonator, method of manufacturing bulk acoustic wave resonator, bulk acoustic wave resonator unit, filter, and electronic apparatus | |
| JP2003505906A (en) | Resonator structure and filter having the resonator structure | |
| CN110784188B (en) | Resonator and preparation method thereof | |
| CN112039462B (en) | Film bulk acoustic resonator and manufacturing method thereof | |
| CN112039481B (en) | Bulk acoustic wave resonator and method of manufacturing the same | |
| WO2023125757A1 (en) | High-bandwidth cavity type film bulk acoustic resonator and preparation method therefor | |
| CN111082771A (en) | Bulk acoustic wave resonator, preparation method thereof and filter | |
| CN111147040A (en) | Air gap type film bulk acoustic resonator and preparation method thereof | |
| CN113708740A (en) | Piezoelectric film bulk acoustic resonator and preparation method thereof | |
| CN111342803A (en) | Film bulk acoustic resonator | |
| CN110957989B (en) | Thin film bulk acoustic resonator and method for manufacturing the same | |
| CN113193846B (en) | Film bulk acoustic resonator with hybrid transverse structural features | |
| CN110868186A (en) | Bulk acoustic wave resonator, method of manufacturing the same, and semiconductor device | |
| CN110868183A (en) | Resonator and filter | |
| CN111600569B (en) | Bulk acoustic wave resonator, method of manufacturing the same, filter, and electronic apparatus | |
| WO2022228385A1 (en) | Bulk acoustic wave resonator having thickened electrode, filter, and electronic device | |
| CN114584096A (en) | High-bandwidth silicon reverse side etching type film bulk acoustic resonator and preparation method thereof | |
| CN217116045U (en) | High-bandwidth silicon reverse side etching type film bulk acoustic resonator | |
| CN216959824U (en) | High-bandwidth cavity type film bulk acoustic resonator | |
| WO2022226911A1 (en) | Piezoelectric mems silicon resonator and forming method therefor, and electronic device | |
| CN213125990U (en) | Frequency-adjustable film bulk acoustic resonator |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20220222 Address after: 510700 room 1103, building B2, No. 136, Kaiyuan Avenue, Huangpu District, Guangzhou, Guangdong Applicant after: Guangzhou Everbright Technology Co.,Ltd. Address before: 517000 Zhongtuo optoelectronics Co., Ltd., Gaoxin 5th Road, Heyuan hi tech Development Zone, Guangdong Province Applicant before: HEYUAN CHOICORE PHOTOELECTRIC TECHNOLOGY Co.,Ltd. |
|
| TA01 | Transfer of patent application right |