CN111786648A - Bulk acoustic wave resonator, method of manufacturing the same, filter, and radio frequency communication system - Google Patents
Bulk acoustic wave resonator, method of manufacturing the same, filter, and radio frequency communication system Download PDFInfo
- Publication number
- CN111786648A CN111786648A CN201910272274.9A CN201910272274A CN111786648A CN 111786648 A CN111786648 A CN 111786648A CN 201910272274 A CN201910272274 A CN 201910272274A CN 111786648 A CN111786648 A CN 111786648A
- Authority
- CN
- China
- Prior art keywords
- layer
- top electrode
- resonance
- bottom electrode
- electrode
- 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
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 36
- 238000004891 communication Methods 0.000 title claims abstract description 11
- 239000000758 substrate Substances 0.000 claims description 67
- 238000000034 method Methods 0.000 claims description 58
- 230000008569 process Effects 0.000 claims description 47
- 238000005530 etching Methods 0.000 claims description 39
- 230000002093 peripheral effect Effects 0.000 claims description 28
- 239000007772 electrode material Substances 0.000 claims description 21
- 238000000151 deposition Methods 0.000 claims description 4
- 238000000059 patterning Methods 0.000 claims description 4
- 239000003814 drug Substances 0.000 claims description 2
- 239000007788 liquid Substances 0.000 claims description 2
- 230000003071 parasitic effect Effects 0.000 abstract description 19
- 239000010410 layer Substances 0.000 description 318
- 239000000463 material Substances 0.000 description 35
- 239000010408 film Substances 0.000 description 29
- 229920002120 photoresistant polymer Polymers 0.000 description 12
- 239000004065 semiconductor Substances 0.000 description 11
- 229910052710 silicon Inorganic materials 0.000 description 11
- 238000000206 photolithography Methods 0.000 description 9
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 8
- 239000010703 silicon Substances 0.000 description 8
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 7
- 229910000577 Silicon-germanium Inorganic materials 0.000 description 7
- 229910052732 germanium Inorganic materials 0.000 description 7
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 7
- 230000009467 reduction Effects 0.000 description 7
- 239000004020 conductor Substances 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 6
- 230000000903 blocking effect Effects 0.000 description 5
- 239000010949 copper Substances 0.000 description 5
- 239000012212 insulator Substances 0.000 description 5
- 239000010948 rhodium Substances 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000005229 chemical vapour deposition Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000003989 dielectric material Substances 0.000 description 4
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 description 4
- 239000010931 gold Substances 0.000 description 4
- 238000005240 physical vapour deposition Methods 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- PIGFYZPCRLYGLF-UHFFFAOYSA-N Aluminum nitride Chemical compound [Al]#N PIGFYZPCRLYGLF-UHFFFAOYSA-N 0.000 description 3
- 229910052581 Si3N4 Inorganic materials 0.000 description 3
- LEVVHYCKPQWKOP-UHFFFAOYSA-N [Si].[Ge] Chemical compound [Si].[Ge] LEVVHYCKPQWKOP-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 229910052741 iridium Inorganic materials 0.000 description 3
- 239000007769 metal material Substances 0.000 description 3
- 238000010295 mobile communication Methods 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 229910052762 osmium Inorganic materials 0.000 description 3
- 229910052763 palladium Inorganic materials 0.000 description 3
- 238000001020 plasma etching Methods 0.000 description 3
- 229910052697 platinum Inorganic materials 0.000 description 3
- 230000001902 propagating effect Effects 0.000 description 3
- 239000010453 quartz Substances 0.000 description 3
- 229910052702 rhenium Inorganic materials 0.000 description 3
- 229910052703 rhodium Inorganic materials 0.000 description 3
- 229910052707 ruthenium Inorganic materials 0.000 description 3
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 3
- 239000010409 thin film Substances 0.000 description 3
- 229910052721 tungsten Inorganic materials 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 2
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910003481 amorphous carbon Inorganic materials 0.000 description 2
- 229910021417 amorphous silicon Inorganic materials 0.000 description 2
- 238000000231 atomic layer deposition Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000001312 dry etching Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- 238000003698 laser cutting Methods 0.000 description 2
- 229910052451 lead zirconate titanate Inorganic materials 0.000 description 2
- 238000001755 magnetron sputter deposition Methods 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 239000011733 molybdenum Substances 0.000 description 2
- SYQBFIAQOQZEGI-UHFFFAOYSA-N osmium atom Chemical compound [Os] SYQBFIAQOQZEGI-UHFFFAOYSA-N 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 2
- 229920005591 polysilicon Polymers 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- WUAPFZMCVAUBPE-UHFFFAOYSA-N rhenium atom Chemical compound [Re] WUAPFZMCVAUBPE-UHFFFAOYSA-N 0.000 description 2
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000010897 surface acoustic wave method Methods 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 2
- 239000010937 tungsten Substances 0.000 description 2
- 238000005019 vapor deposition process Methods 0.000 description 2
- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 description 1
- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 description 1
- 229910052691 Erbium Inorganic materials 0.000 description 1
- GPXJNWSHGFTCBW-UHFFFAOYSA-N Indium phosphide Chemical compound [In]#P GPXJNWSHGFTCBW-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 1
- AXQKVSDUCKWEKE-UHFFFAOYSA-N [C].[Ge].[Si] Chemical compound [C].[Ge].[Si] AXQKVSDUCKWEKE-UHFFFAOYSA-N 0.000 description 1
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- UYAHIZSMUZPPFV-UHFFFAOYSA-N erbium Chemical compound [Er] UYAHIZSMUZPPFV-UHFFFAOYSA-N 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910052735 hafnium Inorganic materials 0.000 description 1
- VBJZVLUMGGDVMO-UHFFFAOYSA-N hafnium atom Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 description 1
- RPQDHPTXJYYUPQ-UHFFFAOYSA-N indium arsenide Chemical compound [In]#[As] RPQDHPTXJYYUPQ-UHFFFAOYSA-N 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 238000010884 ion-beam technique Methods 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 1
- 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 1
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 238000012858 packaging process Methods 0.000 description 1
- UKDIAJWKFXFVFG-UHFFFAOYSA-N potassium;oxido(dioxo)niobium Chemical compound [K+].[O-][Nb](=O)=O UKDIAJWKFXFVFG-UHFFFAOYSA-N 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229910052706 scandium Inorganic materials 0.000 description 1
- SIXSYDAISGFNSX-UHFFFAOYSA-N scandium atom Chemical compound [Sc] SIXSYDAISGFNSX-UHFFFAOYSA-N 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- VSZWPYCFIRKVQL-UHFFFAOYSA-N selanylidenegallium;selenium Chemical compound [Se].[Se]=[Ga].[Se]=[Ga] VSZWPYCFIRKVQL-UHFFFAOYSA-N 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 238000004528 spin coating Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000007669 thermal treatment Methods 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- 235000012431 wafers Nutrition 0.000 description 1
- 238000001039 wet etching Methods 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- 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
-
- 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
- H03H9/15—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
- H03H9/171—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type
- H03H9/172—Means for mounting on a substrate, i.e. means constituting the material interface confining the waves to a volume
- H03H9/174—Membranes
-
- 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
-
- 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
- H03H9/462—Microelectro-mechanical filters
-
- 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
- H03H9/54—Filters comprising resonators of piezo-electric or electrostrictive material
-
- 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
- H03H9/54—Filters comprising resonators of piezo-electric or electrostrictive material
- H03H9/547—Notch filters, e.g. notch BAW or thin film resonator filters
-
- 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
- H03H2009/155—Constructional features of resonators consisting of piezoelectric or electrostrictive material using MEMS techniques
Abstract
The invention provides a bulk acoustic wave resonator, a manufacturing method thereof, a filter and a radio frequency communication system, wherein a top electrode bulge which is formed at the periphery of a piezoelectric resonance layer and is suspended above a cavity can prevent transverse waves generated by the piezoelectric resonance layer from being transmitted to the periphery of the cavity and reflect the transverse waves back to an effective working area, so that the acoustic wave loss is reduced, the quality factor of the resonator is improved, and the performance of a device can be improved finally. Further, the overlapping parts of the bottom electrode overlapping part and the top electrode overlapping part and the cavity are all suspended, and the bottom electrode overlapping part and the top electrode overlapping part are staggered mutually, so that parasitic parameters can be greatly reduced, the problems of electric leakage, short circuit and the like are avoided, and the reliability of the device can be improved.
Description
Technical Field
The invention relates to the technical field of radio frequency communication, in particular to a bulk acoustic wave resonator, a manufacturing method thereof, a filter and a radio frequency communication system.
Background
Radio Frequency (RF) communications, such as those used in mobile phones, require the use of RF filters, each capable of passing a desired frequency and limiting all other frequencies. With the development of mobile communication technology, the amount of mobile data transmission is also rapidly increasing. Therefore, increasing the transmission power of a wireless power transmitting device such as a wireless base station, a micro base station or a repeater becomes a problem that must be considered under the premise that the frequency resources are limited and the mobile communication device should be used as little as possible, and the requirement for the filter power in the front-end circuit of the mobile communication device is higher and higher.
At present, a high-power filter in a wireless base station and other devices is mainly a cavity filter, and the power of the high-power filter can reach hundreds of watts, but the size of the high-power filter is too large. There are also devices that use dielectric filters with average powers of up to 5 watts or more, which are also large in size. Due to the large size, these two filters cannot be integrated into the rf front-end chip.
With the more mature MEMS technology, the filter composed of Bulk Acoustic Wave (BAW) resonators can overcome the above two kinds of filter defects. The bulk acoustic wave resonator has the advantages of incomparable volume of a ceramic dielectric filter and incomparable working frequency and power capacity of a Surface Acoustic Wave (SAW) resonator, and becomes the development trend of the current wireless communication system.
The bulk acoustic wave resonator has a sandwich structure formed by a bottom electrode, a piezoelectric film and a top electrode, converts electric energy into mechanical energy by utilizing the inverse piezoelectric effect of the piezoelectric film, and forms standing waves in a filter formed by the bulk acoustic wave resonator in the form of acoustic waves. Since the speed of an acoustic wave is 5 orders of magnitude smaller than that of an electromagnetic wave, the size of a filter constituted by a bulk acoustic wave resonator is smaller than that of a conventional dielectric filter or the like.
The working principle of the cavity type bulk acoustic wave resonator is that the acoustic waves are reflected at the interface of a bottom electrode or a supporting layer and air, the acoustic waves are limited on a piezoelectric layer, resonance is achieved, and the cavity type bulk acoustic wave resonator has the advantages of being high in Q value, low in insertion loss, capable of being integrated and the like, and is widely adopted.
However, the quality factor (Q) of the currently manufactured cavity bulk acoustic wave resonator cannot be further improved, and thus the requirement of a high-performance radio frequency system cannot be met.
Disclosure of Invention
The invention aims to provide a bulk acoustic wave resonator, a manufacturing method thereof, a filter and a radio frequency communication system, which can improve the quality factor and further improve the device performance.
In order to achieve the above object, the present invention provides a bulk acoustic wave resonator comprising:
a substrate;
the bottom electrode layer is arranged on the substrate, a cavity is formed between the bottom electrode layer and the substrate, and the part of the bottom electrode layer above the cavity extends flatly;
a piezoelectric resonance layer formed on a portion of the bottom electrode layer above the cavity;
the top electrode layer is formed on the piezoelectric resonance layer and is provided with a top electrode protruding portion, the top electrode protruding portion is located on the periphery of the piezoelectric resonance layer, the area of the cavity is arranged in the cavity, the top electrode protruding portion protrudes towards the direction far away from the bottom face of the cavity, and the top electrode protruding portion extends around the periphery of the piezoelectric resonance layer.
The invention also provides a filter comprising at least one bulk acoustic wave resonator according to the invention.
The invention also provides a radio frequency communication system comprising at least one filter according to the invention.
The present invention also provides a method for manufacturing a bulk acoustic wave resonator, comprising:
providing a substrate, and forming a first sacrificial layer with a flat top surface on a part of the substrate;
forming a bottom electrode layer on a part of the first sacrificial layer, wherein the part of the bottom electrode layer on the top surface of the first sacrificial layer is extended flatly;
forming a piezoelectric resonance layer on the bottom electrode layer, wherein the piezoelectric resonance layer exposes a part of the first sacrificial layer and a part of the bottom electrode layer;
forming a second sacrificial layer having a sacrificial protrusion in an area exposed around the piezoelectric resonance layer;
forming a top electrode layer on the piezoelectric resonance layer and a part of the second sacrificial layer around the piezoelectric resonance layer, wherein the part of the top electrode layer covering the sacrificial protrusion forms a top electrode protrusion;
and removing the second sacrificial layer with the sacrificial bumps and the first sacrificial layer, wherein cavities are formed at the positions of the second sacrificial layer with the sacrificial bumps and the first sacrificial layer, and the top electrode protruding parts are positioned in the cavity area at the periphery of the piezoelectric resonance layer and extend around the periphery of the piezoelectric resonance layer.
Compared with the prior art, the technical scheme of the invention has the following beneficial effects:
1. when electric energy is applied to the bottom electrode and the top electrode, a piezoelectric phenomenon generated in the piezoelectric resonance layer generates a desired longitudinal wave propagating along the thickness direction and an undesired transverse wave propagating along the plane of the piezoelectric resonance layer, the transverse wave is blocked at the protruding part of the top electrode suspended on the cavity at the periphery of the piezoelectric resonance layer and is reflected back to the corresponding area of the piezoelectric resonance layer, and then the loss caused when the transverse wave propagates to the film at the periphery of the cavity is reduced, so that the acoustic wave loss is improved, the quality factor of the resonator is improved, and finally the device performance can be improved.
2. The periphery on piezoelectricity resonance layer and the peripheral alternate segregation of cavity, piezoelectricity resonance layer can not extend to the peripheral substrate top of cavity promptly continuously, can restrict the effective working area of bulk acoustic wave syntonizer in the cavity region completely, and bottom electrode overlap joint portion and top electrode overlap joint portion all can extend to the part edge of cavity (bottom electrode layer and top electrode layer can not cover the cavity comprehensively promptly), can reduce the influence of the longitudinal vibration that the rete produced piezoelectricity resonance layer around the cavity from this, the performance is improved.
3. Even if the top electrode protruding part and the bottom electrode layer have mutually overlapped parts, a gap structure is arranged between the overlapped parts, so that parasitic parameters can be greatly reduced, the problems of electric contact and the like of the top electrode layer and the bottom electrode layer in a cavity region are avoided, and the reliability of the device can be improved.
4. Bottom electrode overlap joint portion and top electrode overlap joint portion all are unsettled with the overlap section of cavity, and bottom electrode overlap joint portion and top electrode overlap joint portion stagger each other in the region of cavity (the two does not overlap in the cavity region promptly), can greatly reduced parasitic parameter from this to avoid bottom electrode overlap joint portion and top electrode overlap joint portion to contact and the electric leakage that arouses, short circuit scheduling problem, can improve the device reliability.
5. The bottom electrode overlapping part completely covers the cavity above the cavity part where the bottom electrode overlapping part is located, so that the membrane layer above the bottom electrode overlapping part with a large area can be strongly and mechanically supported, and the problem of failure of a device due to cavity collapse is avoided.
6. The top electrode bulge surrounds the top electrode resonance part for a circle, and can block transverse waves from the periphery of the piezoelectric resonance layer in an all-around mode, and therefore good quality factors are obtained.
7. Bottom electrode resonance portion and bottom electrode overlap joint portion adopt same rete to form, and thick even, and top electrode bellying, top electrode resonance portion and top electrode overlap joint portion adopt same rete to form, and thick even, can simplify technology from this, reduce cost, and because the membrane thickness of top electrode bellying is the same basically with other parts of top electrode layer, consequently the cracked condition of top electrode bellying can not appear, can improve the reliability of device.
8. The bottom electrode layer is flat in the regional part of cavity, can be favorable to improving the thickness homogeneity of the film in the active area on the one hand, and on the other hand is favorable to reducing the degree of difficulty of the sculpture technology when forming the piezoelectricity resonance layer, avoids appearing the remaining problem of piezoelectricity material sculpture because of the top surface of bottom electrode layer is uneven to reduce parasitic parameter.
Drawings
Fig. 1A is a schematic top view of a bulk acoustic wave resonator according to an embodiment of the present invention.
Fig. 1B and 1C are schematic sectional views along the lines XX 'and YY' in fig. 1.
Fig. 2A to 2C are schematic top-view structural diagrams of bulk acoustic wave resonators according to other embodiments of the present invention.
Fig. 2D is a schematic cross-sectional view of a bulk acoustic wave resonator according to another embodiment of the present invention.
Fig. 3 is a flowchart of a method of manufacturing a bulk acoustic wave resonator according to an embodiment of the present invention.
Fig. 4A to 4F are schematic cross-sectional views along XX' in fig. 1A in a method of manufacturing a bulk acoustic wave resonator according to an embodiment of the present invention.
Fig. 5 is a schematic sectional view taken along XX' in fig. 1A in a method of manufacturing a bulk acoustic wave resonator according to another embodiment of the present invention.
Wherein the reference numbers are as follows:
100-a substrate; 101, etching a protective layer; 102-a cavity; 102' -grooves; 102A-active working area; 102B-null area; 103-a first sacrificial layer; 104-bottom electrode layer (i.e. remaining bottom electrode material layer); 1040-bottom electrode lap; 1041-bottom electrode resonance part; 1042 — bottom electrode periphery; 105-a layer of piezoelectric material; 1050-a piezoelectric peripheral portion; 1051-a piezoelectric resonance layer (or called as a piezoelectric resonance part); 106-a second sacrificial layer; 107-sacrificial bumps; 108-top electrode layer (i.e. remaining top electrode material layer); 1080-top electrode lap; 1081-top electrode raised portion; 1082-a top electrode resonance section; 1083-top electrode peripheral portion.
Detailed Description
The technical solution of the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention. Similarly, if the method described herein comprises a series of steps, the order in which these steps are presented herein is not necessarily the only order in which these steps may be performed, and some of the described steps may be omitted and/or some other steps not described herein may be added to the method. In addition, something "offset from" something in this context means that the two do not overlap in the region of the cavity, i.e. that the projections of the two onto the bottom surface of the cavity do not overlap.
Referring to fig. 1A to fig. 1C, fig. 1A is a schematic top view structure diagram of a bulk acoustic wave resonator according to an embodiment of the present invention, fig. 1B is a schematic cross-sectional structure diagram along XX 'in fig. 1, fig. 1C is a schematic cross-sectional structure diagram along YY' in fig. 1A, and the bulk acoustic wave resonator of the present embodiment includes: a substrate, a bottom electrode layer 104, a piezoelectric resonance layer 1051, and a top electrode layer 108.
The substrate comprises a base 100 and an etching protection layer 101 covering the base 100. The substrate 100 may be any suitable substrate known to those skilled in the art, and may be, for example, at least one of the following materials: silicon (Si), germanium (Ge), silicon germanium (SiGe), silicon carbon (SiC), silicon germanium carbon (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP), or other III/V compound semiconductors, and further includes a multilayer structure composed of these semiconductors, or may be Silicon On Insulator (SOI), silicon on insulator (SSOI), silicon germanium on insulator (S-SiGeOI), silicon germanium on insulator (SiGeOI), and germanium on insulator (GeOI), or may be Double-side polished silicon Wafers (DSP), or may be a ceramic substrate such as alumina, quartz, or a glass substrate. The material of the etching protection layer 101 may be any suitable dielectric material, including but not limited to at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, and the like, and the etching protection layer may be used to increase the structural stability of the finally manufactured bulk acoustic wave resonator, increase the isolation between the bulk acoustic wave resonator and the substrate 100, and reduce the resistivity requirement on the substrate 100, and on the other hand, protect other regions of the substrate from being etched in the process of manufacturing the bulk acoustic wave resonator, thereby improving the performance and reliability of the device.
A cavity 102 is formed between the bottom electrode layer 104 and the substrate. Referring to fig. 1A to fig. 1C, in the present embodiment, the cavity 102 may be formed by sequentially etching the etching protection layer 101 and the base 100 with a partial thickness through an etching process, so as to form a groove structure with a whole bottom recessed in the substrate. However, the technology of the present invention is not limited thereto, and referring to fig. 2D, in another embodiment of the present invention, the cavity 102 may also be formed above the top surface of the etching protection layer 101 by removing the sacrificial layer protruding from the surface of the etching protection layer 101 by a post-removal method, so as to form a cavity structure protruding from the surface of the etching protection layer 101. In addition, in the present embodiment, the bottom surface of the cavity 102 is rectangular, but in other embodiments of the present invention, the bottom surface of the cavity 102 may also be circular, oval, or polygonal other than rectangular, such as pentagonal, hexagonal, etc.
The piezoelectric resonance layer 1051, which may be referred to as a piezoelectric resonance portion, is located in an upper region of the cavity 102 (which may be said to be located in a region of the cavity 102) corresponding to an effective operating region of the bulk acoustic wave resonator, and the piezoelectric resonance layer 1051 is provided between the bottom electrode layer 104 and the top electrode layer 108. The bottom electrode layer 104 comprises a bottom electrode lap 1040 and a bottom electrode resonance part 1041 which are connected in sequence, the part of the bottom electrode layer 104 above the cavity 102 is extended flatly, that is, the top surface of the part of the bottom electrode lap 1040 above the cavity is flush with the top surface of the bottom electrode resonance part 1041, and the bottom surface of the part of the bottom electrode lap 1040 above the cavity is flush with the bottom surface of the bottom electrode resonance part 1041. The top electrode layer 108 includes a top electrode overlapping portion 1080, a top electrode protruding portion 1081 and a top electrode resonance portion 1082 which are connected in sequence, the bottom electrode resonance portion 1041 and the top electrode resonance portion 1082 are overlapped with the piezoelectric resonance layer 1051, the cavity 102 and a region corresponding to the overlapped bottom electrode resonance portion 1041, the piezoelectric resonance layer 1051 and the top electrode resonance portion 1082 form an effective working area 102A of the bulk acoustic wave resonator, a portion of the cavity 102 other than the effective working area 102A is an inactive area 102B, the piezoelectric resonance layer 1051 is located in the effective working area 102A and separated from a film layer around the cavity 102, the effective working area of the bulk acoustic wave resonator can be completely limited in the area of the cavity 102, the influence of the film layer around the cavity on longitudinal vibration generated by the piezoelectric resonance layer can be reduced, parasitic parameters generated in the inactive area 102B can be reduced, and device performance can be improved. The bottom electrode resonance portion 1041, the piezoelectric resonance layer 1051, and the top electrode resonance portion 1082 are flat structures whose upper and lower surfaces are planar, and the top electrode protrusion portion 1081 is located above the cavity 102B on the periphery of the active region 102A, electrically connected to the top electrode resonance portion 1082, and protrudes toward a direction away from the bottom surface of the cavity 102. The top electrode projection portion 1081 as a whole projects upward with respect to the top surface of the top electrode resonance portion 1082 and is located in the cavity region (i.e., 102B) in the periphery of the piezoelectric resonance layer 1051. The top electrode protrusion 1081 may be a solid structure, or may be a hollow structure, preferably a hollow structure, so as to make the film thickness of the top electrode layer 108 uniform, and avoid the solid top electrode protrusion 1081 from causing the deformation of the top electrode resonance portion 1082, the piezoelectric resonance layer 1051 below the top electrode resonance portion, and the bottom electrode resonance portion 1041, thereby further improving the resonance factor. The bottom electrode resonance part 1041 and the top electrode resonance part 1082 are polygonal (both the top surface and the bottom surface are polygonal), and the shapes of the bottom electrode resonance part 1041 and the top electrode resonance part 1082 may be similar (as shown in fig. 2A and 2C) or identical (as shown in fig. 1A and 2B). The piezoelectric resonance layer 1051 has a polygonal structure similar to the shapes of the bottom electrode resonance portion 1041 and the top electrode resonance portion 1082.
Referring to fig. 1A to 1C, in the present embodiment, the bottom electrode layer 104, the piezoelectric resonance layer 1051, and the top electrode layer 108 form a film layer structure in a shape of a "watch", a corner of the bottom electrode overlap portion 1040 and the bottom electrode resonance portion 1041 is aligned, a corner of the top electrode overlap portion 1080 and the top electrode resonance portion 1082 is aligned, the bottom electrode overlap portion 1040 and the top electrode overlap portion 1080 correspond to two bands of the "watch", the top electrode protrusion portion 1081 is disposed along an edge of the top electrode resonance portion 1082 and is only disposed in a region where the top electrode overlap portion 1080 and the top electrode resonance portion 1082 are aligned, the top electrode protrusion portion 1081 corresponds to a connection structure between a dial of the "watch" and a band, a stacked structure of the bottom electrode resonance portion 1041, the piezoelectric resonance layer 1051, and the top electrode resonance portion 1082 in the active region 102A corresponds to a film layer of the watch, the watch dial is connected to a film layer on a substrate around the cavity except for a band portion, the remaining portion is separated from the film layer on the substrate around the cavity by the cavity. That is, in this embodiment, the top electrode protrusion 1081 extends around the peripheral direction of the piezoelectric resonance layer 1051, and the top electrode protrusion 1081 only surrounds a part of the edge of the piezoelectric resonance layer 1051 along the peripheral direction of the piezoelectric resonance layer 1051, and with reference to the plane where the piezoelectric resonance layer 1051 is located, the top electrode protrusion 1081 and the bottom electrode overlapping portion 1040 partially reside on two sides of the piezoelectric resonance layer 1051 and are opposite to each other, so that while a certain transverse wave blocking effect is achieved, the reduction of the area of the inactive area 102B not covered by the top electrode overlapping portion 1080 and the bottom electrode overlapping portion 1040 can be facilitated, and further the reduction of the device size is facilitated, and the reduction of the area of the top electrode overlapping portion 1080 and the bottom electrode overlapping portion 1040 is facilitated, so as to further reduce parasitic parameters, and improve the electrical performance of the device. The bottom electrode overlapping portion 1040 is electrically connected to one side of the bottom electrode resonance portion 1041, and extends from the bottom electrode resonance portion 1041 to the upper portion of the partial etching protection layer 101 at the periphery of the cavity 102 after suspending above the cavity (i.e., 102B) at the outer side of the bottom electrode resonance portion 1041; the top electrode bonding portion 1080 is electrically connected to one side of the top electrode protrusion portion 1081, which faces away from the top electrode resonance portion 1082, and extends from the top electrode protrusion portion 1081 to the upper side of the partial etching protection layer 101 at the periphery of the cavity 102 after being suspended above the cavity (i.e., 102B) at the outer side of the top electrode protrusion portion 1081; the bottom electrode overlapping portion 1040 and the top electrode overlapping portion 1080 extend to the upper side of the substrate outside two opposite sides of the cavity 102, and at this time, the bottom electrode overlapping portion 1040 and the top electrode overlapping portion 1080 are staggered with each other (that is, the two are not overlapped) in the cavity 102 region, so that parasitic parameters can be reduced, the problems of electric leakage, short circuit and the like caused by the contact of the bottom electrode overlapping portion and the top electrode overlapping portion are avoided, and the device performance is improved. The bottom electrode strap 1040 may be used to connect to a corresponding signal line to transmit a corresponding signal to the bottom electrode resonance portion 1041, the top electrode strap 1080 may be used to connect to a corresponding signal line, to transmit a corresponding signal to the top electrode resonance portion 1082 through the top electrode protrusion portion 1081, so that the bulk acoustic wave resonator can normally operate, specifically, a longitudinally extended mode or a "piston" mode is excited by applying a time-varying voltage to the bottom electrode resonance portion 1041 and the top electrode resonance portion 1082 through the bottom electrode strap portion 1040 and the top electrode strap portion 1080, respectively, the piezoelectric resonance layer 1051 converts energy in the form of electric energy into a longitudinal wave, in the process, parasitic transverse waves are generated, and the top electrode bulge 1081 can prevent the transverse waves from being transmitted to the film layer on the periphery of the cavity and limit the transverse waves in the area of the cavity 102, so that energy loss caused by the transverse waves is avoided, and the quality factor is improved.
Preferably, the line widths of the top electrode protrusion portions 1081 are respectively the minimum line widths allowed by the corresponding processes, and the horizontal distances between the top electrode protrusion portions 1081 and the piezoelectric resonance layers 1051 are the minimum distances allowed by the corresponding processes, so that the top electrode protrusion portions 1081 can achieve a certain transverse wave blocking effect, and at the same time, the reduction of the device area can be facilitated.
In addition, the side wall of the top electrode protrusion 1081 is an inclined side wall relative to the top surface of the piezoelectric resonance layer, as shown in fig. 1B, the cross section of the top electrode protrusion 1081 along the line XX' in fig. 1A is trapezoidal or trapezoid-like, and the angles α 1 and α 2 between the two side walls of the top electrode protrusion 1081 and the top surface of the piezoelectric resonance layer 1051 are both less than or equal to 45 degrees, so that the top electrode protrusion 1081 is prevented from being broken due to the fact that the side wall of the top electrode protrusion 1081 is too vertical, the effect of transmitting signals to the top electrode resonance portion 1082 is further affected, and meanwhile, the thickness uniformity of the whole top electrode layer 108 can be improved.
In a preferred embodiment of the present invention, the bottom electrode resonance portion 1041 and the bottom electrode overlapping portion 1040 are formed by a same film layer manufacturing process (i.e. a same film layer manufacturing process), the top electrode resonance portion 1082, the top electrode protrusion portion 1081 and the top electrode overlapping portion 1080 are formed by a same film layer manufacturing process (i.e. a same film layer manufacturing process), i.e. the bottom electrode resonance portion 1041 and the bottom electrode overlapping portion 1040 are integrally formed, and the top electrode resonance portion 1082, the top electrode protrusion portion 1081 and the top electrode overlapping portion 1080 are integrally formed, so that the process can be simplified and the cost can be reduced, wherein the film layer materials for manufacturing the bottom electrode resonance portion 1041 and the bottom electrode overlapping portion 1040 and the film layer materials for manufacturing the top electrode resonance portion 1082, the top electrode protrusion portion 1081 and the top electrode overlapping portion 1080 can respectively use any suitable conductive materials or semiconductor materials known in the art, the conductive material may be a metal material having a conductive property, such as one or more of aluminum (Al), copper (Cu), platinum (Pt), gold (Au), molybdenum (Mo), tungsten (W), iridium (Ir), osmium (Os), rhenium (Re), palladium (Pd), rhodium (Rh), and ruthenium (Ru), and the semiconductor material may be Si, Ge, SiGe, SiC, SiGeC, or the like. In other embodiments of the present invention, the bottom electrode resonance portion 1041 and the bottom electrode overlapping portion 1040 may be formed by different film layer manufacturing processes, and the top electrode resonance portion 1082, the top electrode protruding portion 1081, and the top electrode overlapping portion 1080 may be formed by different film layer manufacturing processes, as the process cost and the process technology allow.
Referring to fig. 2A to 2C, in order to further improve the transverse wave blocking effect, the top electrode protrusion portion 1081 extends to more continuous sides of the top electrode resonance portion 1082. For example, referring to fig. 2A, the piezoelectric resonance layer 1051, the top electrode resonance portion 1082 and the bottom electrode resonance portion 1041 are all pentagonal planar structures, the area of the piezoelectric resonance layer 1051 is the smallest, the area of the top electrode resonance portion 1082 is the second, and the area of the bottom electrode resonance portion 1041 is the largest, the top electrode protrusion portion 1081 is disposed along and connected to a plurality of sides of the top electrode resonance portion 1082, and the projection of the top electrode protrusion portion 1081 on the bottom surface of the cavity 102 exposes the projection of the portion of the bottom electrode resonance portion 1041 connected with the bottom electrode overlapping portion 1040 on the bottom surface of the cavity 102, so that the top electrode protrusion portion 1081 and the bottom electrode overlapping portion 1040 do not overlap, and the parasitic parameters can be reduced. For another example, referring to fig. 2B, the piezoelectric resonance layer 1051, the top electrode resonance portion 1082, and the bottom electrode resonance portion 1041 are all pentagonal planar structures, the area of the piezoelectric resonance layer 1051 is the smallest, the areas, shapes, etc. of the top electrode resonance portion 1082 and the bottom electrode resonance portion 1041 are the same or substantially the same, the top electrode protrusion 1081 surrounds a circumference of the top electrode resonance portion 1082, and the projections of the top electrode resonance portion 1082 and the bottom electrode resonance portion 1041 on the bottom surface of the cavity 102 are overlapped, so that the transverse wave generated by the piezoelectric resonance layer 1051 can be blocked in all directions by the closed ring-shaped DE top electrode protrusion 1081.
Referring to fig. 2A to 2C, in the embodiments of the present invention, the bottom electrode strap 1040 is electrically connected to at least one edge or at least one corner of the bottom electrode resonance portion 1041, and extends from the corresponding edge of the bottom electrode resonance portion 1041 to above a portion of the etching protection layer 101 at the periphery of the cavity 102 after suspending above the cavity (i.e., 102B) outside the bottom electrode resonance portion 1041; the top electrode bonding portion 1080 is electrically connected to at least one edge or at least one corner of the top electrode protrusion 1081 facing away from the top electrode resonance portion 1082, and extends from the top electrode protrusion 1081 to the top of the partial etching protection layer 101 at the periphery of the cavity 102 after suspending above the cavity (i.e., 102B) at the outer side of the top electrode protrusion 1081, and the top electrode bonding portion 1080 and the bottom electrode bonding portion 1040 may be directly connected to each other or separated from each other on the bottom surface of the cavity 102, so that the top electrode bonding portion 1080 and the bottom electrode bonding portion 1040 may be staggered without overlapping in the area of the cavity 102. For example, as shown in fig. 1A and fig. 2A to 2B, the bottom electrode strap 1040 may extend only above a portion of the substrate at one side periphery of the cavity 102, the top electrode strap 1080 extends only above a portion of the substrate at one side periphery of the cavity 102, and projections of the top electrode strap 1080 and the bottom electrode strap 1040 on the bottom surface of the cavity 102 are separated from each other, so as to avoid introducing parasitic parameters and possibly causing problems such as leakage and short circuit when the top electrode strap 1080 and the bottom electrode strap 1040 are overlapped. Preferably, however, referring to fig. 2C, the bottom electrode strap 1040 is disposed along all sides of the bottom electrode resonance portion 1041 and extends continuously to the substrate at the periphery of the cavity 102, so that the bottom electrode strap 1040 can extend to the upper side of the substrate at more directions at the periphery of the cavity 102, that is, at this time, the bottom electrode strap 1040 completely covers the cavity 102 above the cavity portion where it is located, so that the supporting force for the film layer of the effective working area 102A can be enhanced by laying the bottom electrode strap 1040 with a large area, and the cavity 102 is prevented from collapsing. It is further preferred that when the bottom electrode strap 1040 extends above a portion of the substrate in more directions around the periphery of the cavity 102, the top electrode strap 1080 extends only above a portion of the substrate in one direction around the periphery of the cavity 102, for example, when the cavity 102 is rectangular in plan view, the top electrode strap 1080 extends only above the substrate around one side of the cavity 102, the bottom electrode strap 1040 extends to three other sides of the cavity 102, and the top electrode strap 1080 and the bottom electrode strap 1040 are directly connected or separated from each other in projection onto the bottom surface of the cavity 102, i.e., the bottom electrode strap 1040 completely covers the cavity 102 above the cavity portion where it is located, and does not overlap the top electrode strap 1080 in the width direction of the top electrode strap 1080, thereby avoiding the large area top electrode strap 1080 from being disposed vertically with the bottom electrode strap 1040 and the like structure And excessive parasitic parameters are introduced due to the overlapping, so that the electrical performance and the reliability of the device can be further improved.
In various embodiments of the present invention, when the cavity 102 has a polygonal top view shape, the bottom electrode overlapping portion 1040 and the top electrode overlapping portion 1080 respectively expose at least one side of the cavity, so that at least one end of each of the bottom electrode resonance portion 1041 connected to the bottom electrode overlapping portion 1040 and the top electrode resonance portion 1082 connected to the top electrode protrusion portion 1081 is completely suspended, which may be beneficial to reducing the area of the inactive area 102B, further reducing parasitic parameters such as parasitic capacitance generated in the inactive area 102B, and improving device performance. Preferably, the top electrode protrusion 1081 is staggered with respect to the bottom electrode overlapping portion 1040 at least above the cavity 102 (i.e., the two overlap each other in the cavity area), so as to further reduce the parasitic parameters such as the parasitic capacitance generated in the inactive area 102B, thereby improving the device performance.
It should be noted that, in order to achieve the best transverse wave blocking effect and facilitate the fabrication of small-sized devices, the closer the top electrode protrusion 1081 is to the active working area 102A, the better the line width of the top electrode protrusion 1081 is, preferably, the line width of the top electrode protrusion 1081 is the minimum line width allowed by the corresponding process, and the horizontal distance between the top electrode protrusion 1081 and the active working area 102A (i.e., the piezoelectric resonance layer 1051) is the minimum distance allowed by the corresponding process.
It should be noted that in the above embodiments, the top electrode resonance portion 1082 and the bottom electrode resonance portion 1041 have similar or identical shapes and have the same area, or the area of the bottom electrode resonance portion 1041 is larger than the area of the top electrode resonance portion 1082, but the technical solution of the present invention is not limited thereto, and in other embodiments of the present invention, the shapes of the top electrode resonance portion 1082 and the bottom electrode resonance portion 1041 may not be similar, but preferably, the shape of the top electrode projection 1081 is adapted to the shape of the piezoelectric resonance layer 1051, which can extend along at least one side of the piezoelectric resonance layer 1051.
In addition, it is found through research that most of the parasitic transverse waves of the bulk acoustic wave resonator are transmitted through the connection structure between the film layer on the effective working area 102A and the substrate at the periphery of the cavity, so in the embodiments of the present invention, on the premise of ensuring that the film layer of the effective working area 102A can be effectively supported, the area (or line width) of the top electrode overlapping portion 1080 can be controlled to be the smallest as possible, and the area (or line width) of the bottom electrode overlapping portion 1040 is the smallest.
An embodiment of the present invention further provides a filter, including at least one bulk acoustic wave resonator according to any of the embodiments of the present invention described above.
An embodiment of the present invention further provides a radio frequency communication system, including at least one filter according to an embodiment of the present invention.
Referring to fig. 3, an embodiment of the invention further provides a method for manufacturing a bulk acoustic wave resonator (for example, the bulk acoustic wave resonators shown in fig. 1A to 2C) of the invention, including:
s1, providing a substrate, and forming a first sacrificial layer with a flat top surface on a part of the substrate;
s2, forming a bottom electrode layer on a part of the first sacrificial layer, wherein the part of the bottom electrode layer on the top surface of the first sacrificial layer is extended flatly;
s3, forming a piezoelectric resonance layer on the bottom electrode layer, wherein the piezoelectric resonance layer exposes a part of the first sacrificial layer and a part of the bottom electrode layer;
s4, forming a second sacrificial layer with sacrificial bumps in the exposed area around the piezoelectric resonance layer;
s5, forming a top electrode layer on the piezoelectric resonance layer and a part of the second sacrificial layer around the piezoelectric resonance layer, wherein the part of the top electrode layer covering the sacrificial protrusion forms a top electrode protrusion;
and S6, removing the second sacrificial layer with the sacrificial bumps and the first sacrificial layer, wherein cavities are formed at the positions of the second sacrificial layer with the sacrificial bumps and the first sacrificial layer, and the top electrode protruding parts are located in the cavity area at the periphery of the piezoelectric resonance layer and extend around the periphery of the piezoelectric resonance layer.
Referring to fig. 1A and 1B and fig. 4A to 4B, in step S1 of the present embodiment, a first sacrificial layer is formed on a portion of a substrate by a process of etching the substrate to form a groove and filling a material into the groove, and the specific implementation process includes:
first, referring to fig. 1A and fig. 4A, a substrate, specifically, a base 100 is provided, and an etching protection layer 101 is covered on the base 100. The etching protection layer 101 may be formed on the substrate 100 by any suitable process, such as a thermal treatment method, such as thermal oxidation, thermal nitridation or thermal oxynitridation, or a deposition method, such as chemical vapor deposition, physical vapor deposition or atomic layer deposition. Further, the thickness of the etching protection layer 101 may be set reasonably according to the actual device process requirements, and is not limited specifically herein.
Next, with continued reference to fig. 1A, 1B and 4A, the substrate is etched by photolithography and etching processes to form at least one groove 102'. The etching process may be a wet etching or a dry etching process, wherein preferably a dry etching process is used, including but not limited to Reactive Ion Etching (RIE), ion beam etching, plasma etching or laser cutting. The depth and shape of the groove 102 ' are determined by the depth and shape of the cavity required by the bulk acoustic wave resonator to be manufactured, the cross-sectional shape of the groove 102 ' is rectangular, and in other embodiments of the present invention, the cross-section of the groove 102 ' may be any other suitable shape, such as a circle, an ellipse, or other polygons (e.g., pentagon, hexagon, etc.) except for a rectangle.
Then, referring to fig. 1A, 1B and 4B, the first sacrificial layer 103 may be filled in the groove 102' by processes of vapor deposition, thermal oxidation, spin coating or epitaxial growth, and the like, where the first sacrificial layer 103 may be selected from a semiconductor material, a dielectric material, a photoresist material, and the like different from the substrate 100 and the etching protection layer 101, for example, when the substrate 100 is a Si substrate, the first sacrificial layer 103 may be Ge, and the formed first sacrificial layer 103 may further cover the etching protection layer 101 at the periphery of the groove or the top surface is higher than the top surface of the etching protection layer 101 at the periphery of the groove; then, the top of the first sacrificial layer 103 is planarized to the top surface of the etching protection layer 101 by a Chemical Mechanical Planarization (CMP) process, so that the first sacrificial layer 103 is only located in the groove 102', and the top surface of the first sacrificial layer 103 is flush with the top surface of the etching protection layer 101 around the first sacrificial layer 103, thereby providing a flat process surface for the subsequent formation of the bottom electrode layer 104 with a flat surface.
Referring to fig. 1A, 1B and 4C, in step S2, first, a bottom electrode material layer (not shown) may be covered on the surfaces of the etching protection layer 101 and the first sacrificial layer 103 by a suitable method according to the material of the bottom electrode to be formed, for example, the bottom electrode material layer may be formed by physical vapor deposition such as magnetron sputtering and evaporation, or chemical vapor deposition; then, a photoresist layer (not shown) with a bottom electrode pattern defined thereon is formed on the bottom electrode material layer by using a photolithography process, the bottom electrode material layer is etched using the photoresist layer as a mask to form a bottom electrode layer (i.e., the remaining bottom electrode material layer) 104, and then the photoresist layer is removed. The bottom electrode material layer may use any suitable conductive material or semiconductor material known in the art, wherein the conductive material may be a metal material having a conductive property, such as one or more of aluminum (Al), copper (Cu), platinum (Pt), gold (Au), molybdenum (Mo), tungsten (W), iridium (Ir), osmium (Os), rhenium (Re), palladium (Pd), rhodium (Rh), and ruthenium (Ru), or a semiconductor material, such as Si, Ge, SiGe, SiC, SiGeC, or the like. In this embodiment, the bottom electrode layer (the remaining bottom electrode material layer) 104 includes a bottom electrode resonance portion 1041 covering the active working region 102A to be formed, a bottom electrode strap 1040 on the partial etching protection layer 101 extending from one side of the bottom electrode resonance portion 1041 to the outside of the recess 102' through the surface of the first sacrificial layer 103, and a bottom electrode peripheral portion 1042 separated from the bottom electrode resonance portion 1041, where the bottom electrode peripheral portion 1042 may be connected to a side of the bottom electrode strap 1040 facing away from the bottom electrode resonance portion 1041 to serve as a metal contact of the bulk acoustic wave resonator to be formed in the region, or may be separated from the bottom electrode strap 1040 to serve as a part of the bottom electrode strap of the adjacent bulk acoustic wave resonator, and in other embodiments of the present invention, the bottom electrode peripheral portion 1042 may be omitted. The bottom electrode resonance part 1041 may be pentagonal in top view shape, and may also be quadrilateral or hexagonal in other embodiments of the present invention, and the bottom electrode overlapping part 1040 is electrically connected to at least one side or at least one corner of the bottom electrode resonance part 1041, and extends from the corresponding side of the bottom electrode resonance part 1041 to the top surface of the partial etching protection layer 101 at the periphery of the groove 102' through the top surface of the first sacrificial layer 103 outside the bottom electrode resonance part 1041. In addition, since the top surface of the first sacrificial layer 103 and the top surface of the etching protection layer 101 are flush in this embodiment, the bottom surface and the top surface of the bottom electrode layer 104 can be flush, and the bottom electrode layer 104 extends flat in the global range, that is, the bottom electrode resonance portion 1041 and the bottom electrode bridging portion 1040 have flush bottom surfaces and flush top surfaces. Preferably, as shown in fig. 2C, the bottom electrode strap 1040 completely covers the cavity 102 above the cavity portion where it is located, and has no overlap with the top electrode strap 1080 in the width direction of the top electrode strap 1080, so as to improve the supporting force for the subsequent film layer and avoid the overlap with the top electrode strap 1080 to introduce unnecessary parasitic parameters. The bottom electrode resonance 1041 may serve as an input electrode or an output electrode that receives or provides an electrical signal such as a Radio Frequency (RF) signal.
Referring to fig. 1A, 1B and 4C, in step S3, a piezoelectric material layer 105 may be deposited by any suitable method known to those skilled in the art, such as chemical vapor deposition, physical vapor deposition or atomic layer deposition; then, photolithography is usedThe process forms a photoresist layer (not shown) with a defined piezoelectric thin film pattern on the piezoelectric material layer 105, then etches the piezoelectric material layer 105 with the photoresist layer as a mask to form the piezoelectric resonance layer 1051, and then removes the photoresist layer. As the material of the piezoelectric material layer 105, aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), lithium niobate (LiNbO) can be used3) Quartz (Quartz), potassium niobate (KNbO)3) Or lithium tantalate (LiTaO)3) And the like, and combinations thereof. When the piezoelectric material layer 105 includes aluminum nitride (AlN), the piezoelectric material layer 105 may further include a rare earth metal, for example, at least one of scandium (Sc), erbium (Er), yttrium (Y), and lanthanum (La). Further, when the piezoelectric material layer 105 includes aluminum nitride (AlN), the piezoelectric material layer 105 may further include a transition metal, for example, at least one of zirconium (Zr), titanium (Ti), manganese (Mn), and hafnium (Hf). The piezoelectric material layer 105 remaining after patterning includes a piezoelectric resonance layer 1051 and a piezoelectric peripheral portion 1050 that are separated from each other, and the piezoelectric resonance layer 1051 is located on the bottom electrode resonance portion 1041, exposes the bottom electrode overlap portion 1040, and may completely cover or partially cover the bottom electrode resonance portion 1041. The shape of the piezoelectric resonance layer 1051 may be the same as or different from that of the bottom electrode resonance unit 1041, and the planar shape thereof may be pentagonal, or may be other polygonal shapes such as a quadrangle, a hexagon, a heptagon, or an octagon. The piezoelectric peripheral portion 1050 can form a gap with the piezoelectric resonator layer 1051 to expose a portion of the first sacrificial layer 103 above the bottom electrode strap 1040 and around the bottom electrode resonator portion 1041, and further limit a formation region of a subsequent second sacrificial layer by the formed gap while providing a relatively flat process surface for formation of a subsequent sacrificial protrusion, and the piezoelectric peripheral portion 1050 can also achieve isolation between a subsequently formed top electrode peripheral portion and a previously formed bottom electrode peripheral portion 1042 while providing a relatively flat process surface for formation of a subsequent second sacrificial layer and a top electrode layer.
Referring to fig. 1A, 1B and 4D, in step S4, first, a second sacrificial layer 106 may be coated in the piezoelectric periphery 1050, the piezoelectric resonator layer 1051 and the gap between the piezoelectric periphery 1050 and the piezoelectric resonator layer 1051 by a coating process or a vapor deposition process, and the second sacrificial layer 106 may fill the gap between the piezoelectric periphery 1050 and the piezoelectric resonator layer 1051, wherein the material of the second sacrificial layer 106 may be at least one selected from amorphous carbon, photoresist, dielectric material (e.g., silicon nitride, silicon oxycarbide, porous material, etc.) or semiconductor material (e.g., polysilicon, amorphous silicon, germanium), etc.; then, the second sacrificial layer 106 is top-planarized by a CMP process so that the second sacrificial layer 106 is filled only in the gap between the piezoelectric periphery 1050 and the piezoelectric resonance layer 1051, and the piezoelectric periphery 1050, the piezoelectric resonance layer 1051, and the second sacrificial layer 106 constitute a flat upper surface. In other embodiments of the present invention, the second sacrificial layer 106 on the upper surfaces of the piezoelectric peripheral portion 1050 and the piezoelectric resonance layer 1051 may also be removed by an etch-back process so as to fill only the gap between the piezoelectric peripheral portion 1050 and the piezoelectric resonance layer 1051. Then, a sacrificial material (not shown) may be coated on the piezoelectric peripheral portion 1050, the piezoelectric resonance layer 1051 and the second sacrificial layer 106 through a suitable process such as a coating process or a vapor deposition process, the thickness of the sacrificial material depends on the protrusion height of the sacrificial protrusion 107 to be formed, and the sacrificial material may be at least one selected from amorphous carbon, photoresist, a dielectric material (e.g., silicon nitride, silicon oxycarbide, a porous material, etc.) or a semiconductor material (e.g., polysilicon, amorphous silicon, germanium), etc., and is preferably the same as the second sacrificial layer 106, so as to save cost and simplify the process; then, the sacrificial material is patterned by a photolithography process or a process combining photolithography and etching to form the sacrificial protrusion 107, and the shape, size, position, and the like of the sacrificial protrusion 107 determine the shape, size, position, and the like of the top electrode protrusion to be formed later. Preferably, the side wall of the sacrificial protrusion 107 is an inclined side wall inclined with respect to the plane in which the piezoelectric resonance layer 1051 is located (i.e., the top surface of the piezoelectric resonance layer 1051), and both the included angles θ 1 and θ 2 between the side wall of the sacrificial protrusion 107 and the top surface of the piezoelectric resonance layer 1051 are less than or equal to 45 degrees, so that the material coverage of the subsequent top electrode protrusion 1081 is facilitated, the occurrence of fracture is avoided, and the thickness uniformity is improved. Further preferably, the line width of the sacrificial protrusion 107 is the minimum line width allowed by the corresponding process, and the horizontal distance between the sacrificial protrusion 107 and the piezoelectric resonance layer 1051 (the horizontal distance between the sacrificial protrusion 107 and the piezoelectric resonance layer 1051) is the minimum distance allowed by the corresponding process, thereby facilitating the reduction of the device size while achieving a better transverse wave blocking effect. In other embodiments of the present invention, the sacrificial protrusion 107 and the second sacrificial layer 106 may be formed by the same process, for example, by covering the second sacrificial layer 106 in the piezoelectric peripheral portion 1050, the piezoelectric resonance layer 1051, and the gap between the piezoelectric peripheral portion 1050 and the piezoelectric resonance layer 1051, the thickness of the second sacrificial layer 106 being not less than the sum of the thickness of the piezoelectric resonance layer 1051 and the thickness of the sacrificial protrusion 107; then, the second sacrificial layer 106 is patterned by an etching process to form the second sacrificial layer 106 filled only in the gap between the piezoelectric periphery 1050 and the piezoelectric resonance layer 1051, and a part of the second sacrificial layer 106 has a sacrificial protrusion 107, a bottom surface of which may be flush with a top surface of the piezoelectric resonance layer 1051, and a remaining part of the top surface of the second sacrificial layer 106 is flush with the top surface of the piezoelectric resonance layer 1051.
Referring to fig. 1A, fig. 1B and fig. 4E, in step S5, a top electrode material layer (not shown) may be first coated on the surfaces of the piezoelectric periphery 1050, the piezoelectric resonator layer 1051, the second sacrificial layer 106 and the sacrificial protrusion 107 by a suitable method according to the material of the top electrode to be formed, for example, the top electrode material layer may be formed by physical vapor deposition such as magnetron sputtering and evaporation or chemical vapor deposition, and the thickness of the top electrode material layer may be uniform at each position; then, a photoresist layer (not shown) with a top electrode pattern defined thereon is formed on the top electrode material layer by using a photolithography process, the top electrode material layer is etched using the photoresist layer as a mask to form a top electrode layer (i.e., the patterned top electrode material layer or the remaining top electrode material layer) 108, and then the photoresist layer is removed. The top electrode material layer may use any suitable conductive material or semiconductor material known in the art, wherein the conductive material may be a metal material with conductive property, such as one or more of Al, Cu, Pt, Au, Mo, W, Ir, Os, Re, Pd, Rh, and Ru, and the semiconductor material may be Si, Ge, SiGe, SiC, SiGeC, etc. In this embodiment, the top electrode layer 108 includes a top electrode resonance portion 1082 covering the piezoelectric resonance layer 1051, a top electrode protrusion 1081 covering the sacrificial protrusion 107, a top electrode pad 1080 extending from the top electrode protrusion 1081 to the piezoelectric peripheral portion 1050 outside the top electrode protrusion 1081 through a part of the top surface of the second sacrificial layer 106, and a top electrode peripheral portion 1083 separated from both the top electrode resonance portion 1082 and the top electrode protrusion 1081, the top electrode peripheral portion 1083 may be connected to a side of the top electrode pad 1080 facing away from the top electrode resonance portion 1082 to serve as one metal contact of the bulk acoustic wave resonator to be formed in the area, and may be separated from the top electrode pad 1080 to serve as a part of the top electrode pad of an adjacent bulk acoustic wave resonator, and in other embodiments of the present invention, the top electrode peripheral portion 1083 may be omitted. The top electrode resonance portion 1082 may have the same or different top view shape as that of the piezoelectric resonance layer 1051, for example, a pentagonal top view shape, and preferably has an area larger than that of the piezoelectric resonance layer 1051, so that the piezoelectric resonance layer 1051 is completely sandwiched by the top electrode resonance portion 1082 and the bottom electrode resonance portion 1041, thereby facilitating reduction of the device size and reduction of parasitic parameters. The top electrode layer 108 may serve as an input electrode or an output electrode that receives or provides electrical signals, such as Radio Frequency (RF) signals. For example, when the bottom electrode layer 104 is used as an input electrode, the top electrode layer 108 may be used as an output electrode, and when the bottom electrode layer 104 is used as an output electrode, the top electrode layer 108 may be used as an input electrode, and the piezoelectric resonance layer 1051 converts an electric signal input through the top electrode resonance portion 1082 or the bottom electrode resonance portion 1041 into a bulk acoustic wave. For example, the piezoelectric resonance layer 1051 converts an electric signal into a bulk acoustic wave by physical vibration. The top electrode projections 1081 are disposed along at least one side of the top electrode resonance portion 1082 and are connected to a corresponding side of the top electrode resonance portion 1082, i.e., the top electrode projections 1081 are disposed along the side of the top electrode resonance portion 1082 and are disposed at least in an area where the top electrode lap 1080 and the top electrode resonance portion 1082 are aligned, e.g., the top electrode projections 1081 encircle the top electrode resonance portion 1082 for a closed loop configuration (as shown in fig. 2B and 2C), and further, e.g., the top electrode projections 1081 extend over a plurality of contiguous sides of the top electrode resonance portion 1082 for an open loop configuration (as shown in fig. 2A). The top electrode strap 1080 is electrically connected to a side of the top electrode protrusion 1081 facing away from the top electrode resonance portion 1082, and extends from the top electrode protrusion 1081 to a top surface of a portion of the etching protection layer 101 outside the groove 102 'through a top surface of a portion of the second sacrificial layer 106, the top electrode strap 1080 and the bottom electrode strap 1040 are staggered with each other (i.e., they do not overlap in a region of the cavity 102), and the top electrode strap 1080 and the bottom electrode strap 1040 respectively expose at least one side of the groove 102'. In an embodiment of the invention, referring to fig. 1A and fig. 2A, in the projection on the bottom surface of the groove 102', the projection of the top electrode protrusion 1081 at least exposes the projection of the boundary where the bottom electrode resonance part 1041 is connected by the bottom electrode overlapping part 1040. The projections of the top electrode strap 1080 and the bottom electrode strap 1040 on the bottom surface of the recess 102 'are directly connected or separated from each other, and the top electrode strap 1080 may extend only over a portion of the substrate at the periphery of one side of the recess 102'.
Referring to fig. 1A, 1B and 4F, in step S6, holes may be punched at the edge of the piezoelectric peripheral portion 1050 facing the groove 102' or the periphery of the device region of the bulk acoustic wave resonator by a photolithography combined with an etching process or a laser cutting process to form release holes (not shown) capable of exposing at least one of a portion of the first sacrificial layer 103, a portion of the sacrificial protrusion 107 or the second sacrificial layer 106 exposed by the sacrificial protrusion 107; then, gas and/or liquid medicine is introduced into the release hole to remove the sacrificial protrusion 107, the second sacrificial layer 106 and the first sacrificial layer 103, and the second groove is emptied again to form a cavity 102, where the cavity 102 includes a space of the groove 102', a space increased by the top electrode protrusion 1081, and a space under the top electrode protrusion 1081 and originally occupied by the second sacrificial layer 106. Among them, the bottom electrode resonance portion 1041, the piezoelectric resonance layer 1051, and the top electrode resonance portion 1082 suspended above the cavity 102 and stacked in this order constitute an exclusive-stereo thin film, and a portion where the bottom electrode resonance portion 1041, the piezoelectric resonance layer 1051, the top electrode resonance portion 1082, and the cavity 102 overlap each other in the vertical direction is an effective area, defined as an effective working area 102A, in which, when electric power such as a radio frequency signal is applied to the bottom electrode resonance portion 1041 and the top electrode resonance portion 1082, vibration and resonance are generated in the thickness direction (i.e., the longitudinal direction) of the piezoelectric resonance layer 1051 due to a piezoelectric phenomenon generated in the piezoelectric resonance layer 1051, and the other area of the cavity 102 is an ineffective area 102B in which, even when the electric power is applied to the bottom electrode layer 108 and the top electrode layer 104, no resonance is generated due to the piezoelectric phenomenon. The independent acoustic thin film composed of the bottom electrode resonance portion 1041, the piezoelectric resonance layer 1051, and the top electrode resonance portion 1082 suspended above the effective working area 102A and stacked in this order can output a radio frequency signal of a resonance frequency corresponding to the vibration of the piezoelectric phenomenon of the piezoelectric resonance layer 1051. Specifically, when electric power is applied to the top electrode resonance portion 1082 and the bottom electrode resonance portion 1041, a bulk acoustic wave is generated by a piezoelectric phenomenon generated in the piezoelectric resonance layer 1051. In this case, the generated bulk acoustic wave has a parasitic transverse wave in addition to the desired longitudinal wave, and the transverse wave is blocked at the top electrode protrusion 1081, and the transverse wave is confined in the active region 102A and prevented from propagating into the film layer at the periphery of the cavity, thereby improving acoustic loss caused by propagation of the transverse wave into the film layer at the periphery of the cavity, resulting in an improvement in the quality factor of the resonator and ultimately enabling an improvement in device performance.
It should be noted that the step S6 may be performed after all the film layers above the cavity 102 to be formed are manufactured, so that the first sacrificial layer 103 and the second sacrificial layer 106 may be continuously utilized to protect the space where the cavity 102 is located and the film layer structure formed thereon by stacking the bottom electrode layer 104 to the top electrode layer 108, so as to avoid the risk of cavity collapse when the subsequent processes are continued after the cavity 102 is formed. In addition, the release hole formed in step S6 may be left at all times, so that the release hole can be sealed by a subsequent packaging process such as two-substrate bonding, thereby closing the cavity 102.
It should be noted that, in step S1 of the method for manufacturing a bulk acoustic wave resonator according to each of the above embodiments, a first sacrificial layer 103 is formed on a portion of the substrate by a process of etching the substrate to form a groove 102 'and filling the groove 102', so that the cavity 102 formed in step S6 is a groove structure with the entire bottom recessed in the substrate, but the technical solution of the present invention is not limited thereto, in step S1 of other embodiments of the present invention, the first sacrificial layer 103 protruding over the substrate as a whole may also be formed by film deposition in combination with photolithography and etching processes, so that the cavity 102 formed in step S6 is a cavity structure protruding on the surface of the substrate as a whole, specifically, referring to fig. 2D and 5, in step S1, the grooves 102' for making the cavities 102 are no longer formed in the provided substrate, covering a first sacrificial layer 103 on the etching protection layer 101 on the surface of the substrate 100; then, the first sacrificial layer 103 is patterned by a process of photolithography and etching, only the first sacrificial layer 103 covering the region 102 remains, and the first sacrificial layer 103 is formed on a portion of the substrate, where the first sacrificial layer 103 may be a step structure with a narrow top and a wide bottom, a top surface of the first sacrificial layer 103 is flat, and a thickness of the first sacrificial layer 103 determines a depth of a subsequently formed cavity 102. In this embodiment, the subsequent steps are identical to those of the corresponding portions in the method of manufacturing the bulk acoustic wave resonator of the embodiment shown in fig. 4A to 4F, it is not repeated herein, except that the corresponding sidewalls of the bottom electrode peripheral portion 1043, the bottom electrode overlapping portion 1040, the piezoelectric peripheral portion 1050, the top electrode peripheral portion 1083, and the top electrode overlapping portion 1080 are formed to be deformed in conformity with the raised first sacrificial layer 103, and the longitudinal cross section of the bottom electrode layer 104 is changed to a "Z" shape, at this time, the portion of the bottom electrode layer 104 above the cavity 102 is extended flatly, that is, the bottom electrode strap 1040 is located above the cavity (excluding the portion corresponding to the sidewall of the first sacrificial layer 103) with its top surface flush with the top surface of the bottom electrode resonance portion 1041, and the bottom electrode strap 1040 is located above the cavity (excluding the portion corresponding to the sidewall of the first sacrificial layer 103) with its bottom surface flush with the bottom surface of the bottom electrode resonance portion 1041.
The bulk acoustic wave resonator of the present invention preferably employs the method for manufacturing a bulk acoustic wave resonator of the present invention, so that the bottom electrode overlapping portion is manufactured together with the bottom electrode resonance portion, and the top electrode overlapping portion, the top electrode protrusion portion, and the top electrode resonance portion are manufactured together, thereby simplifying the process and reducing the manufacturing cost.
It will be apparent to those skilled in the art that various changes and modifications may be made in the invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (21)
1. A bulk acoustic wave resonator, comprising:
a substrate;
the bottom electrode layer is arranged on the substrate, a cavity is formed between the bottom electrode layer and the substrate, and the part of the bottom electrode layer above the cavity extends flatly;
a piezoelectric resonance layer formed on a portion of the bottom electrode layer above the cavity;
the top electrode layer is formed on the piezoelectric resonance layer and is provided with a top electrode protruding portion, the top electrode protruding portion is located on the periphery of the piezoelectric resonance layer, the area of the cavity is arranged in the cavity, the top electrode protruding portion protrudes towards the direction far away from the bottom face of the cavity, and the top electrode protruding portion extends around the periphery of the piezoelectric resonance layer.
2. The bulk acoustic wave resonator according to claim 1, wherein the bottom electrode layer includes a bottom electrode resonance portion and a bottom electrode lap portion, the bottom electrode resonance portion having a flat top surface and overlapping the piezoelectric resonance layer, the bottom electrode lap portion extending flat from one side of the bottom electrode resonance portion to above a part of the substrate on the periphery of the cavity, the top electrode layer further including a top electrode resonance portion having a flat top surface and overlapping the piezoelectric resonance layer, and a top electrode lap portion extending around the peripheral direction of the top electrode resonance portion and connecting the top electrode resonance portion, the top electrode lap portion having one end connected to the top electrode lap portion and the other end lapped to the substrate on the periphery of the cavity; the bottom electrode overlapping part and the top electrode overlapping part are staggered with each other.
3. The bulk acoustic wave resonator according to claim 2, wherein the bottom electrode resonance portion and the top electrode resonance portion are each polygonal.
4. The bulk acoustic wave resonator according to claim 3, wherein the top electrode bump is provided along an edge of the top electrode resonance section and at least in a region where the top electrode lap and the top electrode resonance section are aligned.
5. The bulk acoustic wave resonator according to claim 4, wherein the top electrode bump is staggered from at least the bottom electrode lap above the cavity, or wherein the top electrode bump surrounds the top electrode resonance portion by one revolution.
6. The bulk acoustic wave resonator according to claim 2, wherein the bottom electrode land and the bottom electrode resonance portion are formed using the same film layer, and the top electrode bump, the top electrode land, and the top electrode resonance portion are formed using the same film layer.
7. The bulk acoustic wave resonator according to claim 3, wherein the bottom electrode lap completely covers the cavity above a portion of the cavity where the bottom electrode lap is located, and does not overlap with the top electrode lap in a width direction of the top electrode lap.
8. The bulk acoustic wave resonator according to any one of claims 1 to 7, wherein a horizontal distance between the top electrode bump and the piezoelectric resonance layer is a minimum distance allowed by a process of manufacturing the top electrode bump.
9. The bulk acoustic wave resonator according to any one of claims 1 to 7, wherein a side wall of the top electrode boss is inclined with respect to a top surface of the piezoelectric resonance layer, and an angle between the side wall of the top electrode boss and the top surface of the piezoelectric resonance layer is 45 degrees or less.
10. The bulk acoustic resonator according to any one of claims 1 to 7, wherein a line width of the top electrode bump is a minimum line width allowed by a process of manufacturing the top electrode bump.
11. The bulk acoustic wave resonator according to any one of claims 1 to 7, wherein the cavity is a groove structure whose entire bottom is recessed in the substrate or a cavity structure which is provided on the surface of the substrate as a whole.
12. A filter comprising at least one bulk acoustic wave resonator according to any one of claims 1 to 11.
13. A radio frequency communication system comprising at least one filter according to claim 12.
14. A method of manufacturing a bulk acoustic wave resonator, comprising:
providing a substrate, and forming a first sacrificial layer with a flat top surface on a part of the substrate;
forming a bottom electrode layer on a part of the first sacrificial layer, wherein the part of the bottom electrode layer on the top surface of the first sacrificial layer is extended flatly;
forming a piezoelectric resonance layer on the bottom electrode layer, wherein the piezoelectric resonance layer exposes a part of the first sacrificial layer and a part of the bottom electrode layer;
forming a second sacrificial layer having a sacrificial protrusion in an area exposed around the piezoelectric resonance layer;
forming a top electrode layer on the piezoelectric resonance layer and a part of the second sacrificial layer around the piezoelectric resonance layer, wherein the part of the top electrode layer covering the sacrificial protrusion forms a top electrode protrusion;
and removing the second sacrificial layer with the sacrificial bumps and the first sacrificial layer, wherein cavities are formed at the positions of the second sacrificial layer with the sacrificial bumps and the first sacrificial layer, and the top electrode protruding parts are positioned in the cavity area at the periphery of the piezoelectric resonance layer and extend around the periphery of the piezoelectric resonance layer.
15. The method of fabricating a bulk acoustic wave resonator according to claim 14, wherein the step of forming a first sacrificial layer having a flat top surface on a portion of the substrate comprises: etching the substrate to form a second groove in the substrate; forming a first sacrificial layer to fill the second groove, and enabling the top surface of the first sacrificial layer to be flat; alternatively, the first and second electrodes may be,
the step of forming a first sacrificial layer on a portion of a substrate includes: covering a first sacrificial layer on the substrate and flattening the top surface of the first sacrificial layer; and patterning the first sacrificial layer to form a first sacrificial layer protruding from a part of the substrate.
16. The method of manufacturing a bulk acoustic wave resonator according to claim 14, wherein the step of removing the second sacrificial layer having the sacrificial protrusion and the first sacrificial layer includes:
after forming the top electrode layer, forming at least one release hole, wherein the release hole at least exposes a part of the first sacrificial layer, a part of the sacrificial protrusion or a part of the second sacrificial layer except the sacrificial protrusion;
and introducing gas and/or liquid medicine into the release hole to remove the second sacrificial layer with the sacrificial protrusion and the first sacrificial layer.
17. The method of manufacturing a bulk acoustic wave resonator according to claim 14, wherein the step of forming the bottom electrode layer includes: depositing a bottom electrode material layer to cover the first sacrificial layer and the substrate at the periphery of the first sacrificial layer; and patterning the bottom electrode material layer to form a bottom electrode lapping part and a bottom electrode resonance part which are sequentially connected, wherein the bottom electrode resonance part is overlapped with the piezoelectric resonance layer, one end of the bottom electrode lapping part is lapped on the substrate on the periphery of the cavity, and the top surface of the part of the bottom electrode lapping part, which is positioned in the cavity area, is flush with the bottom electrode resonance part.
18. The method of manufacturing a bulk acoustic wave resonator according to claim 17, wherein the step of forming the top electrode layer includes: depositing a top electrode material layer to cover the second sacrificial layer with the sacrificial protrusion and the piezoelectric resonance layer; patterning the top electrode material layer to form a top electrode overlapping part, a top electrode protruding part and a top electrode resonance part which are sequentially connected, wherein the top electrode resonance part is overlapped with the piezoelectric resonance layer, one end of the top electrode overlapping part back to the top electrode protruding part extends to the upper part of the substrate on the periphery of the cavity, and the top electrode overlapping part and the bottom electrode overlapping part are mutually staggered.
19. The method of manufacturing a bulk acoustic wave resonator according to claim 18, wherein the bottom electrode resonance section and the top electrode resonance section are each polygonal, and the top electrode projection is provided along a side of the top electrode resonance section at least in a region where the top electrode lap section and the top electrode resonance section are aligned.
20. The method of manufacturing a bulk acoustic wave resonator according to claim 14, wherein a horizontal distance between the top electrode bump and the piezoelectric resonance layer is a minimum distance allowed by a process of manufacturing the top electrode bump.
21. The method of manufacturing a bulk acoustic wave resonator according to claim 14, wherein a line width of the top electrode bump is a minimum line width allowed by a process of manufacturing the top electrode bump.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910272274.9A CN111786648A (en) | 2019-04-04 | 2019-04-04 | Bulk acoustic wave resonator, method of manufacturing the same, filter, and radio frequency communication system |
| JP2021525820A JP7199758B2 (en) | 2019-04-04 | 2019-09-10 | Bulk acoustic wave resonator, manufacturing method thereof, filter, radio frequency communication system |
| PCT/CN2019/105089 WO2020199506A1 (en) | 2019-04-04 | 2019-09-10 | Bulk acoustic wave resonator and manufacturing method therefor, filter and radio-frequency communication system |
| US17/449,836 US20220029603A1 (en) | 2019-04-04 | 2021-10-04 | Bulk acoustic wave resonator, filter and radio frequency communication system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910272274.9A CN111786648A (en) | 2019-04-04 | 2019-04-04 | Bulk acoustic wave resonator, method of manufacturing the same, filter, and radio frequency communication system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111786648A true CN111786648A (en) | 2020-10-16 |
Family
ID=72664457
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910272274.9A Pending CN111786648A (en) | 2019-04-04 | 2019-04-04 | Bulk acoustic wave resonator, method of manufacturing the same, filter, and radio frequency communication system |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP7199758B2 (en) |
| CN (1) | CN111786648A (en) |
| WO (1) | WO2020199506A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114124022A (en) * | 2021-11-30 | 2022-03-01 | 中国科学院上海微系统与信息技术研究所 | Suspended resonator for enhancing heat dissipation and preparation method |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20070279154A1 (en) * | 2006-05-31 | 2007-12-06 | Fujitsu Media Devices Limited & Fujitsu Limited | Filter having multiple piezoelectric thin-film resonators |
| US20120200199A1 (en) * | 2009-10-22 | 2012-08-09 | Taiyo Yuden Co., Ltd. | Piezoelectric thin-film resonator |
| CN108123695A (en) * | 2016-11-30 | 2018-06-05 | 三星电机株式会社 | Bulk acoustic wave resonator |
| CN108336982A (en) * | 2017-01-17 | 2018-07-27 | 三星电机株式会社 | Bulk acoustic wave resonator |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7388454B2 (en) * | 2004-10-01 | 2008-06-17 | Avago Technologies Wireless Ip Pte Ltd | Acoustic resonator performance enhancement using alternating frame structure |
| JP2007295310A (en) * | 2006-04-25 | 2007-11-08 | Matsushita Electric Works Ltd | Baw resonator |
| CN102301590B (en) * | 2009-02-20 | 2014-07-02 | 宇部兴产株式会社 | Thin-film piezoelectric resonator and thin-film piezoelectric filter using same |
| CN102223142B (en) * | 2011-08-13 | 2019-09-10 | 张�浩 | Acoustic resonator |
| JP2013138425A (en) * | 2011-12-27 | 2013-07-11 | Avago Technologies Wireless Ip (Singapore) Pte Ltd | Solid-mount bulk acoustic wave resonator structure with bridge |
| JP6519284B2 (en) * | 2015-04-01 | 2019-05-29 | セイコーエプソン株式会社 | Electro-optical device, method of manufacturing electro-optical device, and electronic apparatus |
| DK3377886T3 (en) * | 2015-11-20 | 2020-10-12 | Qorvo Us Inc | Acoustic resonator with reduced mechanical voltage of an active area for improved shear mode response |
| KR101843244B1 (en) * | 2016-02-17 | 2018-05-14 | 삼성전기주식회사 | Acoustic resonator and manufacturing method thereof |
| KR101922878B1 (en) * | 2016-07-14 | 2018-11-29 | 삼성전기 주식회사 | Bulk-acoustic wave resonator device |
| DE102017117870B3 (en) * | 2017-08-07 | 2018-12-27 | RF360 Europe GmbH | BAW resonator with reduced spurious modes and increased quality factor |
-
2019
- 2019-04-04 CN CN201910272274.9A patent/CN111786648A/en active Pending
- 2019-09-10 WO PCT/CN2019/105089 patent/WO2020199506A1/en active Application Filing
- 2019-09-10 JP JP2021525820A patent/JP7199758B2/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20070279154A1 (en) * | 2006-05-31 | 2007-12-06 | Fujitsu Media Devices Limited & Fujitsu Limited | Filter having multiple piezoelectric thin-film resonators |
| US20120200199A1 (en) * | 2009-10-22 | 2012-08-09 | Taiyo Yuden Co., Ltd. | Piezoelectric thin-film resonator |
| CN108123695A (en) * | 2016-11-30 | 2018-06-05 | 三星电机株式会社 | Bulk acoustic wave resonator |
| CN108336982A (en) * | 2017-01-17 | 2018-07-27 | 三星电机株式会社 | Bulk acoustic wave resonator |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114124022A (en) * | 2021-11-30 | 2022-03-01 | 中国科学院上海微系统与信息技术研究所 | Suspended resonator for enhancing heat dissipation and preparation method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP7199758B2 (en) | 2023-01-06 |
| JP2022507320A (en) | 2022-01-18 |
| WO2020199506A1 (en) | 2020-10-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11005448B2 (en) | Film bulk acoustic wave resonators and fabrication methods thereof | |
| CN111786644B (en) | Bulk acoustic wave resonator, method of manufacturing the same, filter, and radio frequency communication system | |
| JP7138988B2 (en) | Bulk acoustic wave resonator, manufacturing method thereof, filter, radio frequency communication system | |
| CN111786649B (en) | Bulk acoustic wave resonator, method of manufacturing the same, filter, and radio frequency communication system | |
| JP7130841B2 (en) | Thin-film bulk acoustic wave resonator and manufacturing method thereof | |
| JP7339694B2 (en) | Bulk acoustic wave resonator, manufacturing method thereof, filter, radio frequency communication system | |
| CN112039467A (en) | Film bulk acoustic resonator and manufacturing method thereof | |
| CN112039462B (en) | Film bulk acoustic resonator and manufacturing method thereof | |
| CN112039469A (en) | Method for manufacturing film bulk acoustic resonator | |
| CN112039475A (en) | Film bulk acoustic resonator, method of manufacturing the same, filter, and radio frequency communication system | |
| JP7194474B2 (en) | Bulk acoustic wave resonator, manufacturing method thereof, filter, radio frequency communication system | |
| EP4175171A1 (en) | Bulk acoustic wave resonator and manufacturing method therefor, filter and electronic device | |
| CN111786654B (en) | Bulk acoustic wave resonator, method of manufacturing the same, filter, and radio frequency communication system | |
| JP7199758B2 (en) | Bulk acoustic wave resonator, manufacturing method thereof, filter, radio frequency communication system | |
| US20220029603A1 (en) | Bulk acoustic wave resonator, filter and radio frequency communication system | |
| CN112311353A (en) | Firmly-arranged bulk acoustic wave resonator and manufacturing method thereof | |
| CN111786652B (en) | Bulk acoustic wave resonator, method of manufacturing the same, filter, and radio frequency communication system | |
| JP7251837B2 (en) | Thin-film bulk acoustic wave resonator and manufacturing method thereof | |
| CN114070223A (en) | Film bulk acoustic resonator and method for manufacturing the same |
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 | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20201016 |
|
| RJ01 | Rejection of invention patent application after publication |