US20220131527A1 - Fbar structure having single crystalline piezoelectric layer and fabricating method thereof - Google Patents
Fbar structure having single crystalline piezoelectric layer and fabricating method thereof Download PDFInfo
- Publication number
- US20220131527A1 US20220131527A1 US17/563,630 US202117563630A US2022131527A1 US 20220131527 A1 US20220131527 A1 US 20220131527A1 US 202117563630 A US202117563630 A US 202117563630A US 2022131527 A1 US2022131527 A1 US 2022131527A1
- Authority
- US
- United States
- Prior art keywords
- layer
- fbar structure
- metal bonding
- bottom electrode
- gold
- 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
- 238000000034 method Methods 0.000 title description 56
- 239000000463 material Substances 0.000 claims abstract description 57
- 229910052751 metal Inorganic materials 0.000 claims description 76
- 239000002184 metal Substances 0.000 claims description 76
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 27
- 238000002161 passivation Methods 0.000 claims description 26
- 239000010949 copper Substances 0.000 claims description 25
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 21
- 229910052710 silicon Inorganic materials 0.000 claims description 21
- 239000010703 silicon Substances 0.000 claims description 21
- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical compound [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 claims description 20
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 18
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 18
- PIGFYZPCRLYGLF-UHFFFAOYSA-N Aluminum nitride Chemical compound [Al]#N PIGFYZPCRLYGLF-UHFFFAOYSA-N 0.000 claims description 17
- 239000010931 gold Substances 0.000 claims description 17
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims description 15
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 15
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 15
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 14
- 239000010936 titanium Substances 0.000 claims description 12
- 229910017755 Cu-Sn Inorganic materials 0.000 claims description 10
- 229910017927 Cu—Sn Inorganic materials 0.000 claims description 10
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 9
- 229910052782 aluminium Inorganic materials 0.000 claims description 9
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 9
- 229910052802 copper Inorganic materials 0.000 claims description 9
- 229910052697 platinum Inorganic materials 0.000 claims description 9
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 9
- 229910052721 tungsten Inorganic materials 0.000 claims description 9
- 239000010937 tungsten Substances 0.000 claims description 9
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 8
- -1 aluminum-germanium Chemical compound 0.000 claims description 7
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 7
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 6
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 6
- 229910052451 lead zirconate titanate Inorganic materials 0.000 claims description 6
- 229910052750 molybdenum Inorganic materials 0.000 claims description 6
- 239000011733 molybdenum Substances 0.000 claims description 6
- 229910052719 titanium Inorganic materials 0.000 claims description 6
- 229910018182 Al—Cu Inorganic materials 0.000 claims description 5
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 claims description 5
- 238000002441 X-ray diffraction Methods 0.000 claims description 5
- BYDQGSVXQDOSJJ-UHFFFAOYSA-N [Ge].[Au] Chemical compound [Ge].[Au] BYDQGSVXQDOSJJ-UHFFFAOYSA-N 0.000 claims description 5
- OFLYIWITHZJFLS-UHFFFAOYSA-N [Si].[Au] Chemical compound [Si].[Au] OFLYIWITHZJFLS-UHFFFAOYSA-N 0.000 claims description 5
- WPPDFTBPZNZZRP-UHFFFAOYSA-N aluminum copper Chemical compound [Al].[Cu] WPPDFTBPZNZZRP-UHFFFAOYSA-N 0.000 claims description 5
- ALKZAGKDWUSJED-UHFFFAOYSA-N dinuclear copper ion Chemical compound [Cu].[Cu] ALKZAGKDWUSJED-UHFFFAOYSA-N 0.000 claims description 5
- QUCZBHXJAUTYHE-UHFFFAOYSA-N gold Chemical compound [Au].[Au] QUCZBHXJAUTYHE-UHFFFAOYSA-N 0.000 claims description 5
- GPYPVKIFOKLUGD-UHFFFAOYSA-N gold indium Chemical compound [In].[Au] GPYPVKIFOKLUGD-UHFFFAOYSA-N 0.000 claims description 5
- PQTCMBYFWMFIGM-UHFFFAOYSA-N gold silver Chemical compound [Ag].[Au] PQTCMBYFWMFIGM-UHFFFAOYSA-N 0.000 claims description 5
- JVPLOXQKFGYFMN-UHFFFAOYSA-N gold tin Chemical compound [Sn].[Au] JVPLOXQKFGYFMN-UHFFFAOYSA-N 0.000 claims description 5
- 229910052763 palladium Inorganic materials 0.000 claims description 5
- 229910052707 ruthenium Inorganic materials 0.000 claims description 5
- 229910052715 tantalum Inorganic materials 0.000 claims description 5
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 5
- 229910021417 amorphous silicon Inorganic materials 0.000 claims description 4
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 4
- 229910052737 gold Inorganic materials 0.000 claims description 4
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims description 4
- 229920005591 polysilicon Polymers 0.000 claims description 4
- 229910052706 scandium Inorganic materials 0.000 claims description 4
- SIXSYDAISGFNSX-UHFFFAOYSA-N scandium atom Chemical compound [Sc] SIXSYDAISGFNSX-UHFFFAOYSA-N 0.000 claims description 4
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 3
- 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 claims description 3
- 239000000758 substrate Substances 0.000 description 15
- JMASRVWKEDWRBT-UHFFFAOYSA-N Gallium nitride Chemical compound [Ga]#N JMASRVWKEDWRBT-UHFFFAOYSA-N 0.000 description 13
- 238000005530 etching Methods 0.000 description 12
- 229910002601 GaN Inorganic materials 0.000 description 9
- 239000013078 crystal Substances 0.000 description 7
- 239000007769 metal material Substances 0.000 description 7
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 6
- 238000005229 chemical vapour deposition Methods 0.000 description 6
- 239000010408 film Substances 0.000 description 6
- 238000005240 physical vapour deposition Methods 0.000 description 6
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 4
- 150000002739 metals Chemical class 0.000 description 4
- 239000004020 conductor Substances 0.000 description 3
- 238000000151 deposition Methods 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000005368 silicate glass Substances 0.000 description 3
- 238000003631 wet chemical etching Methods 0.000 description 3
- 230000008021 deposition Effects 0.000 description 2
- 239000007772 electrode material Substances 0.000 description 2
- 230000004927 fusion Effects 0.000 description 2
- 230000017525 heat dissipation Effects 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 239000012811 non-conductive material Substances 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 238000001039 wet etching Methods 0.000 description 2
- 229910052984 zinc sulfide Inorganic materials 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- GDFCWFBWQUEQIJ-UHFFFAOYSA-N [B].[P] Chemical compound [B].[P] GDFCWFBWQUEQIJ-UHFFFAOYSA-N 0.000 description 1
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000001312 dry etching Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012777 electrically insulating material Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005496 eutectics Effects 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 238000010295 mobile communication Methods 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 238000000059 patterning Methods 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 150000004760 silicates Chemical class 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000010409 thin film Substances 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
- 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
- H03H9/173—Air-gaps
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02007—Details of bulk acoustic wave devices
- H03H9/02015—Characteristics of piezoelectric layers, e.g. cutting angles
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02007—Details of bulk acoustic wave devices
- H03H9/02015—Characteristics of piezoelectric layers, e.g. cutting angles
- H03H9/02031—Characteristics of piezoelectric layers, e.g. cutting angles consisting of ceramic
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02007—Details of bulk acoustic wave devices
- H03H9/02086—Means for compensation or elimination of undesirable effects
- H03H9/02125—Means for compensation or elimination of undesirable effects of parasitic elements
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/13—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials
-
- 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
- H03H9/176—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator consisting of ceramic material
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
- H03H2003/021—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks the resonators or networks being of the air-gap type
Definitions
- the present disclosure relates to the field of semiconductor devices and, in particular, to a film bulk acoustic resonator (FBAR) structure having a single crystalline piezoelectric layer and a method of fabricating such a FBAR structure.
- FBAR film bulk acoustic resonator
- a film bulk acoustic resonator is a device including a thin film that is made of a piezoelectric material and disposed between two electrodes.
- the FBAR device is typically fabricated using semiconductor micro-processing technology.
- the FBAR device may be used in applications requiring high frequency, small size, and light weight.
- An exemplary application of the FBAR device is a filter used in mobile communication devices.
- the FBAR device usually includes a piezoelectric layer grown on a silicon substrate.
- the quality of the piezoelectric layer may not be high enough for achieving superior performance of the FBAR device.
- Embodiments of the present disclosure provide a film bulk acoustic resonator (FBAR) structure.
- the FBAR structure may include a bottom cap wafer; a piezoelectric layer disposed on the bottom cap wafer, the piezoelectric layer including a single crystalline piezoelectric material; a bottom electrode disposed below the piezoelectric layer; a top electrode disposed above the piezoelectric layer; and a cavity disposed below the bottom electrode.
- the single crystalline piezoelectric material may have a crystallinity of less than 0.5 degrees at Full Width Half Maximum (FWHM) measured using X-ray diffraction (XRD).
- FWHM Full Width Half Maximum
- the single crystalline piezoelectric material may include aluminum nitride (AlN), aluminum nitride doped with scandium (ScAlN), zinc oxide (ZnO), or lead zirconate titanate (PZT).
- AlN aluminum nitride
- ScAlN aluminum nitride doped with scandium
- ZnO zinc oxide
- PZT lead zirconate titanate
- the FBAR structure may further include a first insulating layer disposed below the cavity; a second insulating layer disposed above the bottom cap wafer; and a metal bonding layer bonding the first insulating layer with the second insulating layer.
- the metal bonding layer may include at least a first metal bonding layer and a second metal bonding layer.
- a combination of materials of the first metal bonding layer and the second metal bonding layer may be selected from a group of gold-gold (Au—Au), aluminum-copper (Al—Cu), copper-copper (Cu—Cu), gold-silver (Au—Ag), copper-tin (Cu—Sn), aluminum-germanium (Al—Ge), gold-silicon (Au—Si), gold-germanium (Au—Ge), gold-tin (Au—Sn), copper-tin (Cu—Sn), and gold-indium (Au—In).
- the FBAR structure may further include a ground contact layer electrically connecting the metal bonding layer to ground.
- the FBAR structure may further include a ground contact window formed in the first insulating layer and the piezoelectric layer, and exposing the metal bonding layer.
- the ground contact layer may be electrically connected to the metal bonding layer via the ground contact window.
- the first insulating layer and the second insulating layer may include silicon oxide (SiO 2 ) or silicon carbide (SiC).
- the FBAR structure may further include a top passivation layer disposed above the top electrode, and a bottom passivation layer disposed below the bottom electrode.
- the top passivation layer and the bottom passivation layer may include silicon nitride (SiN) or aluminum nitride (AlN).
- the FBAR structure may further include a boundary layer surrounding the cavity.
- the boundary layer may include silicon (Si), silicon nitride (SiN), aluminum nitride (AlN), polysilicon, amorphous silicon, or a stacked combination of two or more of those materials.
- the FBAR structure may further include a bottom electrode contact layer electrically connected with the bottom electrode, and a top electrode contact layer electrically connected with the top electrode.
- the FBAR structure may further include a bottom electrode contact window formed in the piezoelectric layer and exposing the bottom electrode.
- the bottom electrode contact layer may be electrically connected with the bottom electrode via the bottom electrode contact window.
- Each one of the bottom electrode contact layer and the top electrode contact layer may include aluminum (Al), copper (Cu), gold (Au), titanium (Ti), tungsten (W), platinum (Pt), or a stacked combination of two or more of those materials.
- Each one of the top electrode and the bottom electrode may include molybdenum (Mo), aluminum (Al), copper (Cu), platinum (Pt), tantalum (Ta), tungsten (W), palladium (Pd), ruthenium (Ru), or a stacked combination of two or more of those materials.
- the bottom cap wafer may include silicon (Si), silicon carbide (SiC), sapphire (Al 2 O 3 ), or a stacked combination of two or more of those materials.
- a projection of at least one side of the bottom electrode may be located within the cavity.
- a projection of at least one edge of the top electrode may be located within the cavity.
- Embodiments of the present disclosure also provide a method for fabricating a film bulk acoustic resonator (FBAR) structure.
- the method may include obtaining a substrate; growing a buffer layer on the wafer; growing an epitaxial layer on the buffer layer; and growing a piezoelectric layer on the epitaxial layer.
- FBAR film bulk acoustic resonator
- a lattice structure of a material of the buffer layer may match a lattice structure of a material of the epitaxial layer, and the lattice structure of the material of the epitaxial layer may match a lattice structure of a material of the piezoelectric layer.
- the substrate may be formed of silicon (Si), silicon carbide (SiC), or sapphire (Al 2 O 3 ).
- the buffer layer may be formed of gallium nitride (GaN), or aluminum nitride (AlN).
- the buffer layer may be grown on the wafer by using a metal organic chemical vapor deposition (MOCVD) process.
- MOCVD metal organic chemical vapor deposition
- the epitaxial layer may be formed of gallium nitride (GaN), or aluminum nitride (AlN).
- the epitaxial layer may be grown on the buffer layer by using a MOCVD process.
- the method may further include forming a bottom electrode on the piezoelectric layer; forming a sacrificial island on the bottom electrode; and forming a boundary layer on the sacrificial island.
- the method may further include forming a first insulating layer on the boundary layer.
- the method may further include providing a bottom cap wafer with a second insulating layer formed on the bottom cap wafer; and bonding the second insulating layer with the first insulating layer via a metal bonding layer.
- the method may further include removing the wafer, the buffer layer, and the epitaxial layer to expose a surface of the piezoelectric layer.
- the method may further include forming a top electrode on the exposed surface of the piezoelectric layer.
- the method may further include forming a top passivation layer on the top electrode; forming a top electrode window in the top passivation layer to expose the top electrode; and forming a top electrode contact layer in the top electrode window to electrically connect to the top electrode.
- the method may further include forming a ground contact window in the first insulating layer and the piezoelectric layer to expose the metal bonding layer; and forming a ground contact layer in the ground contact window to electrically connect to the metal bonding layer.
- the method may further include forming a bottom electrode contact window in the piezoelectric layer to expose the bottom electrode; and forming a bottom electrode contact layer in the bottom electrode contact window to electrically connect to the bottom electrode.
- the method may further include removing the sacrificial island to form a cavity.
- FIG. 1 is a cross-sectional view of a film bulk acoustic resonator (FBAR) structure, according to an embodiment of the present disclosure.
- FBAR film bulk acoustic resonator
- FIG. 2 is a flow chart of a process of fabricating a FBAR structure according to an embodiment of the present invention.
- FIGS. 3-15 are cross-sectional views of structures formed in the process of FIG. 2 , according to embodiments of the present disclosure.
- relative spatial position such as “front,” “back,” “upper,” “lower,” “above,” “below,” and so forth, are used for explanatory purposes in describing the relationship between a unit or feature depicted in a drawing and another unit or feature therein.
- Terms indicating relative spatial position may refer to positions other than those depicted in the drawings when a device is being used or operated. For example, if a device shown in a drawing is flipped over, a unit which is described as being positioned “below” or “under” another unit or feature will be located “above” the other unit or feature. Therefore, the illustrative term “below” may include positions both above and below.
- a device may be oriented in other ways (e.g., rotated 90 degrees or facing another direction), and descriptive terms that appear in the text and are related to space should be interpreted accordingly.
- a component or layer When a component or layer is said to be “above” another member or layer or “connected to” another member or layer, it may be directly above the other member or layer or directly connected to the other member or layer, or there may be an intermediate component or layer.
- a traditional fabrication method for a bulk acoustic wave (BAW) filter uses silicon as a substrate, grows an electrode layer on the silicon substrate, and grows a piezoelectric layer, such as aluminum nitride (AlN), etc., on the electrode layer. Then, etching and wafer bonding processes are performed to form cavities and resonators.
- a piezoelectric layer such as aluminum nitride (AlN), etc.
- molybdenum (Mo) which is commonly used as the electrode material
- BCC body-centered cubic
- AlN which is commonly used as the piezoelectric material
- the electrode layer has a polycrystalline structure, and therefore the piezoelectric layer grown on the electrode layer also has a polycrystalline structure.
- the piezoelectric material is usually of low quality, having a crystallinity of more than 1.3 degrees, or even more than 1.6 degrees, at Full Width Half Maximum (FWHM) measured using X-ray diffraction (XRD).
- FWHM Full Width Half Maximum
- Embodiments of the present disclosure provide a new approach for growing piezoelectric layer, which includes growing a buffer layer (e.g., AlN buffer layer) on a silicon wafer, growing an epitaxial layer (e.g., GaN epitaxial layer) on the buffer layer, and growing a piezoelectric layer (e.g., AlN or scandium doped aluminum nitride (ScAlN)) on the epitaxial layer.
- a buffer layer e.g., AlN buffer layer
- an epitaxial layer e.g., GaN epitaxial layer
- a piezoelectric layer e.g., AlN or scandium doped aluminum nitride (ScAlN)
- the GaN lattice structure and lattice constant are very close to those of AlN and ScAlN, and the GaN epitaxial layer has single crystalline structure, very high quality single crystalline AlN or ScAlN layer can be grown on the GaN epitaxial layer.
- the single crystalline AlN or ScAlN layer grown using the approach according to the embodiments of the present disclosure may have a crystallinity of less than 0.5 degrees at FWHM measured using XRD, thereby improving the heat dissipation efficiency of a BAW resonator including such single crystalline AlN or ScAlN layer.
- the stress of the AlN buffer layer/GaN epitaxial layer formed on the silicon wafer may be relatively large, resulting in large warpage (deformation) of the silicon wafer, causing difficulty in a subsequent SiO 2 —Si bonding process, which requires less wafer warpage.
- a metal fusion bonding process which can tolerate large wafer warpage, is performed to overcome bonding difficulties.
- a metal bonding layer introduced by the metal fusion bonding process may degrade the performance of the BAW resonator to be significantly.
- the BAW resonator of the embodiments of the present disclosure is provided with a grounding through hole to ground the metal bonding layer.
- FIG. 1 is a cross-sectional view of a film bulk acoustic resonator (FBAR) structure 1000 , according to an embodiment of the present disclosure.
- FBAR structure 1000 includes a bottom cap wafer 200 , a piezoelectric layer 120 disposed on bottom cap wafer 200 , a bottom electrode 130 disposed below piezoelectric layer 120 , a top electrode 190 disposed above piezoelectric layer 120 , and a cavity 1000 a disposed below bottom electrode 130 .
- a projection of at least one edge of bottom electrode 130 is located within cavity 1000 a .
- a projection of at least one edge of top electrode 190 is located within cavity 1000 a.
- Piezoelectric layer 120 includes a single crystalline piezoelectric material.
- a crystallinity of the single crystalline piezoelectric material may be less than 0.5 degrees at Full Width Half Maximum (FWHM) measured using X-ray diffraction (XRD).
- the single crystalline piezoelectric material may include aluminum nitride (AlN), aluminum nitride doped with scandium (ScAlN), zinc oxide (ZnO), or lead zirconate titanate (PZT).
- Bottom cap wafer 200 may include a material such as, for example, silicon (Si), glass (SiO 2 ), or sapphire (Al 2 O 3 ).
- Top and bottom electrodes 190 and 130 may include any suitable conductive material, including various metal materials with conductive properties such as molybdenum (Mo), aluminum (Al), copper (Cu), platinum (Pt), tantalum (Ta), tungsten (W), palladium (Pd), ruthenium (Ru), etc., or a stacked combination of two or more of those conductive metal materials.
- Mo molybdenum
- Al aluminum
- Cu copper
- Ta tantalum
- tungsten W
- Pd palladium
- Ru ruthenium
- top passivation layer 195 is disposed above, and covers a top surface of top electrode 190 .
- a bottom passivation layer 140 is disposed below, and covers a lower surface of, bottom electrode 130 .
- Top passivation layer 195 and bottom passivation layer 140 may include an electrically insulating material such as silicon nitride (SiN) or aluminum nitride (AlN).
- Cavity 1000 a is obtained by removing a sacrificial island (not illustrated in FIG. 1 ).
- the sacrificial island may include silicon oxide.
- a boundary of the removal of the sacrificial island is defined by a boundary layer 160 (also referred-to as an “etch stop layer”), which is disposed below piezoelectric layer 120 and surrounds the sacrificial island before the sacrificial island is removed.
- Boundary layer 160 may include one or more insulating materials such as silicon (Si), silicon nitride (SiN), aluminum nitride (AlN), polysilicon, or amorphous silicon, or a stacked combination of two or more of those materials.
- a first insulating layer 170 is disposed below boundary layer 160 .
- a second insulating layer 210 is disposed above bottom cap wafer 200 .
- a metal bonding layer is disposed between first insulating layer 170 and second insulating layer 210 for bonding first insulating layer 170 with second insulating layer 210 .
- the metal bonding layer includes at least a first metal bonding layer 180 and a second metal bonding layer 220 .
- a combination of the materials of first metal bonding layer 180 and second metal bonding layer 220 may be selected from a group of gold-gold (Au—Au), aluminum-copper (Al—Cu), copper-copper (Cu—Cu), gold-silver (Au—Ag), copper-tin (Cu—Sn), aluminum-germanium (Al—Ge), gold-silicon (Au—Si), gold-germanium (Au—Ge), gold-tin (Au—Sn), copper-tin (Cu—Sn), and gold-indium (Au—In).
- first metal bonding layer 180 may be formed of Au
- second metal bonding layer 220 may be formed of Au.
- first metal bonding layer 180 may be formed of Al
- second metal bonding layer 220 may be formed of Cu.
- a top electrode contact layer 300 is disposed above top passivation layer 195 and is electrically connected to top electrode 190 , via a top electrode contact window formed through top passivation layer 195 .
- a bottom electrode contact layer 310 is disposed above piezoelectric layer 120 and is electrically connected to bottom electrode 130 via a bottom electrode contact window formed through piezoelectric layer 120 .
- a ground contact layer 320 is disposed above piezoelectric layer 120 and is electrically connected to first metal bonding layer 180 via a contact window formed through piezoelectric layer 120 , boundary layer 160 , and first insulating layer 170 .
- Ground contact layer 320 may be connected to ground, such that first metal bonding layer 180 is electrically connected to ground.
- Top electrode contact layer 300 , bottom electrode contact layer 310 , and ground contact layer 320 may include various metals, such as aluminum (Al), copper (Cu), gold (Au), titanium (Ti), tungsten (W), platinum (Pt), etc., or a stacked combination of two or more of those metals.
- various metals such as aluminum (Al), copper (Cu), gold (Au), titanium (Ti), tungsten (W), platinum (Pt), etc., or a stacked combination of two or more of those metals.
- FIG. 2 is a flow chart of a process of fabricating a FBAR structure according to an embodiment of the present disclosure.
- FIGS. 3-15 are cross-sectional views of structures formed in steps S 1 -S 13 of the process of FIG. 2 , according to an embodiment of the present disclosure.
- a substrate 100 is obtained.
- the material of the substrate 100 may be silicon (Si), silicon carbide (SiC), or sapphire (Al 2 O 3 ).
- a buffer layer 105 is grown on substrate 100 by using, for example, a metal organic chemical vapor deposition (MOCVD) process.
- MOCVD metal organic chemical vapor deposition
- an epitaxial layer 110 is grown on buffer layer 105 by using, for example, a MOCVD process.
- piezoelectric layer 120 is grown on epitaxial layer 110 by using, for example, a physical vapor deposition (PVD) process.
- Buffer layer 105 may be a single crystal layer, and may be formed of a material having a lattice structure that matches the material of epitaxial layer 110 or piezoelectric layer 120 .
- buffer layer 105 may be formed of gallium nitride (GaN), or aluminum nitride (AlN), etc.
- the purpose of buffer layer 105 is to grow a high-quality single crystal epitaxial layer 110 . If epitaxial layer 110 is directly grown on substrate 100 , epitaxial layer 110 might not have a single crystalline structure due to the lattice mismatch between the materials of epitaxial layer 110 and substrate 100 .
- Epitaxial layer 110 may be formed of a material having a lattice structure that matches the material of piezoelectric material layer 120 .
- epitaxial layer 110 may be formed of gallium nitride (GaN), or aluminum nitride (AlN), etc.
- epitaxial layer 110 The purpose of epitaxial layer 110 is to grow a high-quality single crystal piezoelectric layer 120 .
- piezoelectric layer 120 is grown on epitaxial layer 110 , which is grown on buffer layer 105 grown on substrate 100 , and the lattice structures of the materials of buffer layer 105 and epitaxial layer 110 match each other, and match that of piezoelectric layer 120 . Therefore, piezoelectric layer 120 formed according to the embodiments of the present disclosure may be a high-quality single crystal structure.
- bottom electrode layer 130 and a bottom passivation layer 140 are sequentially deposited on piezoelectric layer 120 .
- the material of bottom electrode layer 130 may be any suitable conductive material, such as various metal materials with conductive properties or a stack of several conductive metal materials, such as molybdenum (Mo), aluminum (Al), copper (Cu), platinum (Pt), tantalum (Ta), tungsten (W), palladium (Pd), ruthenium (Ru), etc.
- Bottom passivation layer 140 may be made of one or more non-conductive materials such as silicon nitride (SiN) and aluminum nitride (AlN).
- bottom electrode layer 130 and bottom passivation layer 140 are patterned and etched to form bottom electrode 130 and patterned bottom passivation layer 140 .
- the etching process may be a wet chemical etching process, a plasma port etching process, or a combination thereof. This step allows for precise patterning of bottom electrode 130 of the FBAR structure.
- a sacrificial layer 150 is deposited on the structure illustrated in FIG. 5 .
- Sacrificial layer 150 is used to form cavity 1000 a of the FBAR structure.
- Sacrificial layer 150 may include at least one of various types of silicon oxide material, such as pure silicon oxide, phosphor silicate glass (PSG), boron phosphor silicate glass (BPSG), spin on glass (SOG), or fluorinated silicate glass (FSG).
- Sacrificial layer 150 may be deposited by using a chemical vapor deposition (CVD) process, a physical vapor deposition (PVD) process, or a combination of both.
- CVD chemical vapor deposition
- PVD physical vapor deposition
- a top surface of sacrificial layer 150 may be planarized and polished by using, for example, a chemical mechanical polishing (CMP) process.
- CMP chemical mechanical polishing
- sacrificial layer 150 is patterned and etched to form a sacrificial island 150 a .
- the material of sacrificial island 150 a will be removed in a subsequent release etching process, thereby forming cavity 1000 a of the FBAR structure.
- the etching process may be a wet chemical etching process, a plasma etching process, or a combination of those two processes.
- boundary layer 160 is deposited on the structure of FIG. 7 .
- a portion of boundary layer 160 that surrounds sacrificial island 150 a functions as an etch stop layer during the subsequent release etching process for removing sacrificial island 150 a to form cavity 1000 a .
- Boundary layer 160 may include a non-conductive materials such as silicon (Si), silicon nitride (SiN), aluminum nitride (AlN), polysilicon, amorphous silicon, or a stacked combination of two or more of those materials.
- first insulating layer 170 is deposited on the structure illustrated in FIG. 8 . Then, the top surface of first insulating layer 170 is planarized and polished.
- First insulating layer 170 may be deposited by using a CVD process, a PVD process, or a combination of those two processes.
- the material of first insulating layer 170 may be silicon oxide (SiO 2 ), or silicon carbide (SiC), etc.
- the surface planarization and polishing may be performed by using, for example, a CMP process.
- first metal bonding layer 180 is deposited on first insulating layer 170 .
- metals such as titanium (Ti) and nickel (Ni) may be formed on first insulating layer 170 in order to increase the adhesion between first insulating layer 170 and first metal bonding layer 180 .
- First metal bonding layer 180 may include a material that corresponds to the material of second metal bonding layer 220 to achieve metal bonding.
- a combination of the materials of first metal bonding layer 180 and second metal bonding layer 220 may be selected from a group of gold-gold (Au—Au), aluminum-copper (Al—Cu), copper-copper (Cu—Cu), gold-silver (Au—Ag), copper-tin (Cu—Sn), aluminum-germanium (Al—Ge), gold-silicon (Au—Si), gold-germanium (Au—Ge), gold-tin (Au—Sn), copper-tin (Cu—Sn), and gold-indium (Au—In).
- first metal bonding layer 180 may be formed of Au
- second metal bonding layer 220 may be formed of Au.
- first metal bonding layer 180 may be formed of Al
- second metal bonding layer 220 may be formed of Cu.
- bottom cap wafer 200 is obtained.
- Second insulating layer 210 and second metal bonding layer 220 are sequentially deposited on bottom cap wafer 200 .
- metals such as titanium (Ti) and nickel (Ni) may be formed on second insulating layer 210 in order to increase the adhesion between first insulating layer 170 and first metal bonding layer 180 .
- Bottom cap wafer 200 may include a material such as silicon (Si), carbon silicon (SiC), aluminum oxide, quartz, glass, or sapphire (Al 2 O 3 ).
- Second insulating layer 210 may be deposited by using a CVD process, a PVD process, or a combination of those two processes.
- second insulating layer 210 may be silicon oxide (SiO 2 ), or silicon carbide (SiC), etc.
- second metal bonding layer 220 may include a material that corresponds to the material of first metal bonding layer 180 to achieve metal bonding.
- a combination of the materials of first metal bonding layer 180 and second metal bonding layer 220 may be selected from a group of gold-gold (Au—Au), aluminum-copper (Al—Cu), copper-copper (Cu—Cu), gold-silver (Au—Ag), copper-tin (Cu—Sn), aluminum-germanium (Al—Ge), gold-silicon (Au—Si), gold-germanium (Au—Ge), gold-tin (Au—Sn), copper-tin (Cu—Sn), and gold-indium (Au—In).
- step S 10 the structure illustrated in FIG. 10 is flipped over, and first metal bonding layer 180 and second metal bonding layer 220 are bonded together by using a metal bonding process.
- the metal bonding process may be achieved by one or more of eutectic bonding, anodic bonding, or thermal compression bonding.
- step S 11 substrate 100 , buffer layer 105 , and epitaxial layer 110 are removed to expose piezoelectric layer 120 .
- the removal of substrate 100 may be performed by a grinding process.
- the removal of buffer layer 105 and epitaxial layer 110 may be performed by a wet chemical etching process, a plasma dry etching process, or a combination of these two processes.
- top electrode layer 190 is deposited on piezoelectric layer 120 , and top passivation layer 195 is deposited on top electrode layer 190 .
- the material of top electrode layer 190 may be any suitable conductive material, such as various metal materials with conductive properties or a stack of several conductive metal materials, such as molybdenum (Mo), aluminum (Al), copper (Cu), platinum (Pt), Tantalum (Ta), tungsten (W), palladium (Pd), ruthenium (Ru), etc.
- top passivation layer 195 can be silicon nitride (SiN), aluminum nitride (AlN), silicon oxide (SiO 2 ), silicon oxynitride (SiNO), etc., or a stacked combination of those materials.
- top electrode layer 190 and top passivation layer 195 are patterned by etching, to form patterned top passivation layer 195 , top electrode 190 .
- the patterned top passivation layer 195 , piezoelectric layer 120 , boundary layer 160 , and first insulating layer 170 are patterned by etching, for a top electrode contact window exposing top electrode 190 , a bottom electrode contact window exposing bottom electrode 130 , and a ground contact window exposing first metal contact layer 180 .
- a different etching sequence may be used to form the contact windows, which is not limited in the present disclosure.
- passivation layer 195 may be first patterned to form the top electrode contact window; then, piezoelectric layer 120 may be patterned to form the bottom electrode contact window and a part of the ground contact window; and lastly, boundary layer 160 and first insulating layer 170 are patterned to form the remaining part of the ground contact window.
- top electrode contact layer 300 is formed in the top electrode contact window to be electrically connected to top electrode 190 .
- Bottom electrode contact layer 310 is formed in the bottom electrode contact window to be electrically connected to bottom electrode 130 .
- Ground contact layer 320 is formed in the ground contact window to be electrically connected to first metal bonding layer 180 . The purpose of ground contact layer 320 is to connect first metal bonding layer 180 to ground, thereby reducing or eliminating parasitic capacitance introduced by first metal bonding layer 180 and second metal bonding layer 220 .
- top electrode contact layer 300 , bottom electrode contact layer 310 , and ground contact layer 320 may be metal materials, such as aluminum (Al), copper (Cu), gold (Au), titanium (Ti), tungsten (W), platinum (Pt), etc., or a stacked combination of two or more of those materials.
- sacrificial island 150 a is etched and released to form cavity 1000 a by using a release etching process.
- the etching of sacrificial island 150 a is stopped at boundary layer 160 .
- the release etching process may be performed by using hydrofluoric acid solution wet etching, buffered oxide etchant (BOE) solution wet etching, or hydrofluoric acid vapor corrosion, or a combination of those processes.
- BOE buffered oxide etchant
- a high-quality single crystal AlN piezoelectric layer can be obtained by growing a GaN epitaxial layer on a silicon wafer, and then growing the AlN piezoelectric layer on the GaN epitaxial layer.
- the high-quality single crystal AlN piezoelectric layer improves the heat dissipation efficiency of a bulk acoustic wave resonator including the same.
- the metal bonding method was selected to overcome the difficulty in bonding caused by the wafer warpage as a result of the introduction of gallium nitride epitaxial layer.
- the metal bonding layer is grounded in order to avoid the negative impact of the metal bonding layer on the performance.
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
A film bulk acoustic resonator (FBAR) structure includes a bottom cap wafer, a piezoelectric layer disposed on the bottom cap wafer, the piezoelectric layer including a single crystalline piezoelectric material, a bottom electrode disposed below the piezoelectric layer; a top electrode disposed above the piezoelectric layer; and a cavity disposed below the bottom electrode.
Description
- The present disclosure relates to the field of semiconductor devices and, in particular, to a film bulk acoustic resonator (FBAR) structure having a single crystalline piezoelectric layer and a method of fabricating such a FBAR structure.
- A film bulk acoustic resonator (FBAR) is a device including a thin film that is made of a piezoelectric material and disposed between two electrodes. The FBAR device is typically fabricated using semiconductor micro-processing technology.
- Due to its small thickness, the FBAR device may be used in applications requiring high frequency, small size, and light weight. An exemplary application of the FBAR device is a filter used in mobile communication devices.
- The FBAR device usually includes a piezoelectric layer grown on a silicon substrate. However, due to the lattice mismatch between the piezoelectric layer and the silicon substrate, the quality of the piezoelectric layer may not be high enough for achieving superior performance of the FBAR device.
- Therefore, there is a need for a large-scale commercial mass production solution for producing a high-quality piezoelectric layer.
- Embodiments of the present disclosure provide a film bulk acoustic resonator (FBAR) structure. The FBAR structure may include a bottom cap wafer; a piezoelectric layer disposed on the bottom cap wafer, the piezoelectric layer including a single crystalline piezoelectric material; a bottom electrode disposed below the piezoelectric layer; a top electrode disposed above the piezoelectric layer; and a cavity disposed below the bottom electrode.
- The single crystalline piezoelectric material may have a crystallinity of less than 0.5 degrees at Full Width Half Maximum (FWHM) measured using X-ray diffraction (XRD).
- The single crystalline piezoelectric material may include aluminum nitride (AlN), aluminum nitride doped with scandium (ScAlN), zinc oxide (ZnO), or lead zirconate titanate (PZT).
- The FBAR structure may further include a first insulating layer disposed below the cavity; a second insulating layer disposed above the bottom cap wafer; and a metal bonding layer bonding the first insulating layer with the second insulating layer.
- The metal bonding layer may include at least a first metal bonding layer and a second metal bonding layer.
- A combination of materials of the first metal bonding layer and the second metal bonding layer may be selected from a group of gold-gold (Au—Au), aluminum-copper (Al—Cu), copper-copper (Cu—Cu), gold-silver (Au—Ag), copper-tin (Cu—Sn), aluminum-germanium (Al—Ge), gold-silicon (Au—Si), gold-germanium (Au—Ge), gold-tin (Au—Sn), copper-tin (Cu—Sn), and gold-indium (Au—In).
- The FBAR structure may further include a ground contact layer electrically connecting the metal bonding layer to ground.
- The FBAR structure may further include a ground contact window formed in the first insulating layer and the piezoelectric layer, and exposing the metal bonding layer. The ground contact layer may be electrically connected to the metal bonding layer via the ground contact window.
- The first insulating layer and the second insulating layer may include silicon oxide (SiO2) or silicon carbide (SiC).
- The FBAR structure may further include a top passivation layer disposed above the top electrode, and a bottom passivation layer disposed below the bottom electrode.
- The top passivation layer and the bottom passivation layer may include silicon nitride (SiN) or aluminum nitride (AlN).
- The FBAR structure may further include a boundary layer surrounding the cavity.
- The boundary layer may include silicon (Si), silicon nitride (SiN), aluminum nitride (AlN), polysilicon, amorphous silicon, or a stacked combination of two or more of those materials.
- The FBAR structure may further include a bottom electrode contact layer electrically connected with the bottom electrode, and a top electrode contact layer electrically connected with the top electrode.
- The FBAR structure may further include a bottom electrode contact window formed in the piezoelectric layer and exposing the bottom electrode. The bottom electrode contact layer may be electrically connected with the bottom electrode via the bottom electrode contact window.
- Each one of the bottom electrode contact layer and the top electrode contact layer may include aluminum (Al), copper (Cu), gold (Au), titanium (Ti), tungsten (W), platinum (Pt), or a stacked combination of two or more of those materials.
- Each one of the top electrode and the bottom electrode may include molybdenum (Mo), aluminum (Al), copper (Cu), platinum (Pt), tantalum (Ta), tungsten (W), palladium (Pd), ruthenium (Ru), or a stacked combination of two or more of those materials.
- The bottom cap wafer may include silicon (Si), silicon carbide (SiC), sapphire (Al2O3), or a stacked combination of two or more of those materials.
- A projection of at least one side of the bottom electrode may be located within the cavity.
- A projection of at least one edge of the top electrode may be located within the cavity.
- Embodiments of the present disclosure also provide a method for fabricating a film bulk acoustic resonator (FBAR) structure. The method may include obtaining a substrate; growing a buffer layer on the wafer; growing an epitaxial layer on the buffer layer; and growing a piezoelectric layer on the epitaxial layer.
- A lattice structure of a material of the buffer layer may match a lattice structure of a material of the epitaxial layer, and the lattice structure of the material of the epitaxial layer may match a lattice structure of a material of the piezoelectric layer.
- The substrate may be formed of silicon (Si), silicon carbide (SiC), or sapphire (Al2O3).
- The buffer layer may be formed of gallium nitride (GaN), or aluminum nitride (AlN).
- The buffer layer may be grown on the wafer by using a metal organic chemical vapor deposition (MOCVD) process.
- The epitaxial layer may be formed of gallium nitride (GaN), or aluminum nitride (AlN).
- The epitaxial layer may be grown on the buffer layer by using a MOCVD process.
- The method may further include forming a bottom electrode on the piezoelectric layer; forming a sacrificial island on the bottom electrode; and forming a boundary layer on the sacrificial island.
- The method may further include forming a first insulating layer on the boundary layer.
- The method may further include providing a bottom cap wafer with a second insulating layer formed on the bottom cap wafer; and bonding the second insulating layer with the first insulating layer via a metal bonding layer.
- The method may further include removing the wafer, the buffer layer, and the epitaxial layer to expose a surface of the piezoelectric layer.
- The method may further include forming a top electrode on the exposed surface of the piezoelectric layer.
- The method may further include forming a top passivation layer on the top electrode; forming a top electrode window in the top passivation layer to expose the top electrode; and forming a top electrode contact layer in the top electrode window to electrically connect to the top electrode.
- The method may further include forming a ground contact window in the first insulating layer and the piezoelectric layer to expose the metal bonding layer; and forming a ground contact layer in the ground contact window to electrically connect to the metal bonding layer.
- The method may further include forming a bottom electrode contact window in the piezoelectric layer to expose the bottom electrode; and forming a bottom electrode contact layer in the bottom electrode contact window to electrically connect to the bottom electrode.
- The method may further include removing the sacrificial island to form a cavity.
- The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate disclosed embodiments and, together with the description, serve to explain the disclosed embodiments.
-
FIG. 1 is a cross-sectional view of a film bulk acoustic resonator (FBAR) structure, according to an embodiment of the present disclosure. -
FIG. 2 is a flow chart of a process of fabricating a FBAR structure according to an embodiment of the present invention. -
FIGS. 3-15 are cross-sectional views of structures formed in the process ofFIG. 2 , according to embodiments of the present disclosure. - The text below provides a detailed description of the present disclosure in conjunction with specific embodiments illustrated in the attached drawings. However, these embodiments do not limit the present disclosure. The scope of protection for the present disclosure covers changes made to the structure, method, or function by persons having ordinary skill in the art on the basis of these embodiments.
- To facilitate the presentation of the drawings in the present disclosure, the sizes of certain structures or portions may be enlarged relative to other structures or portions. Therefore, the drawings in the present disclosure are only for the purpose of illustrating the basic structure of the subject matter of the present disclosure. The same numbers in different drawings represent the same or similar elements unless otherwise represented.
- Additionally, terms in the text indicating relative spatial position, such as “front,” “back,” “upper,” “lower,” “above,” “below,” and so forth, are used for explanatory purposes in describing the relationship between a unit or feature depicted in a drawing and another unit or feature therein. Terms indicating relative spatial position may refer to positions other than those depicted in the drawings when a device is being used or operated. For example, if a device shown in a drawing is flipped over, a unit which is described as being positioned “below” or “under” another unit or feature will be located “above” the other unit or feature. Therefore, the illustrative term “below” may include positions both above and below. A device may be oriented in other ways (e.g., rotated 90 degrees or facing another direction), and descriptive terms that appear in the text and are related to space should be interpreted accordingly. When a component or layer is said to be “above” another member or layer or “connected to” another member or layer, it may be directly above the other member or layer or directly connected to the other member or layer, or there may be an intermediate component or layer.
- A traditional fabrication method for a bulk acoustic wave (BAW) filter uses silicon as a substrate, grows an electrode layer on the silicon substrate, and grows a piezoelectric layer, such as aluminum nitride (AlN), etc., on the electrode layer. Then, etching and wafer bonding processes are performed to form cavities and resonators. However, the lattice structures of silicon, the electrode material of the electrode layer, and the piezoelectric material of the piezoelectric layer, may not be matched. For example, molybdenum (Mo), which is commonly used as the electrode material, has a body-centered cubic (BCC) crystal structure with a lattice constant of a=3.147 Å, while AlN, which is commonly used as the piezoelectric material, has a wurtzite structure with lattice constants of a=3.11 Å, c=4.978 Å. Additionally, the electrode layer has a polycrystalline structure, and therefore the piezoelectric layer grown on the electrode layer also has a polycrystalline structure. As a result, the piezoelectric material is usually of low quality, having a crystallinity of more than 1.3 degrees, or even more than 1.6 degrees, at Full Width Half Maximum (FWHM) measured using X-ray diffraction (XRD).
- Embodiments of the present disclosure provide a new approach for growing piezoelectric layer, which includes growing a buffer layer (e.g., AlN buffer layer) on a silicon wafer, growing an epitaxial layer (e.g., GaN epitaxial layer) on the buffer layer, and growing a piezoelectric layer (e.g., AlN or scandium doped aluminum nitride (ScAlN)) on the epitaxial layer. GaN has a wurtzite structure having lattice constants of a=3.189 Å, c=5.185 Å). Because the GaN lattice structure and lattice constant are very close to those of AlN and ScAlN, and the GaN epitaxial layer has single crystalline structure, very high quality single crystalline AlN or ScAlN layer can be grown on the GaN epitaxial layer. The single crystalline AlN or ScAlN layer grown using the approach according to the embodiments of the present disclosure may have a crystallinity of less than 0.5 degrees at FWHM measured using XRD, thereby improving the heat dissipation efficiency of a BAW resonator including such single crystalline AlN or ScAlN layer.
- On the other hand, the stress of the AlN buffer layer/GaN epitaxial layer formed on the silicon wafer may be relatively large, resulting in large warpage (deformation) of the silicon wafer, causing difficulty in a subsequent SiO2—Si bonding process, which requires less wafer warpage. According to embodiments of the present disclosure, a metal fusion bonding process, which can tolerate large wafer warpage, is performed to overcome bonding difficulties. However, a metal bonding layer introduced by the metal fusion bonding process, may degrade the performance of the BAW resonator to be significantly. In order to avoid the negative effects of the metal bonding layer on the performance of the BAW resonator, the BAW resonator of the embodiments of the present disclosure is provided with a grounding through hole to ground the metal bonding layer.
-
FIG. 1 is a cross-sectional view of a film bulk acoustic resonator (FBAR)structure 1000, according to an embodiment of the present disclosure. As illustrated inFIG. 1 ,FBAR structure 1000 includes abottom cap wafer 200, apiezoelectric layer 120 disposed onbottom cap wafer 200, abottom electrode 130 disposed belowpiezoelectric layer 120, atop electrode 190 disposed abovepiezoelectric layer 120, and acavity 1000 a disposed belowbottom electrode 130. In some embodiments, a projection of at least one edge ofbottom electrode 130 is located withincavity 1000 a. Alternatively or additionally, in some embodiments, a projection of at least one edge oftop electrode 190 is located withincavity 1000 a. -
Piezoelectric layer 120 includes a single crystalline piezoelectric material. A crystallinity of the single crystalline piezoelectric material may be less than 0.5 degrees at Full Width Half Maximum (FWHM) measured using X-ray diffraction (XRD). The single crystalline piezoelectric material may include aluminum nitride (AlN), aluminum nitride doped with scandium (ScAlN), zinc oxide (ZnO), or lead zirconate titanate (PZT). -
Bottom cap wafer 200 may include a material such as, for example, silicon (Si), glass (SiO2), or sapphire (Al2O3). - Top and
bottom electrodes - As illustrated in
FIG. 1 , atop passivation layer 195 is disposed above, and covers a top surface oftop electrode 190. Abottom passivation layer 140 is disposed below, and covers a lower surface of,bottom electrode 130.Top passivation layer 195 andbottom passivation layer 140 may include an electrically insulating material such as silicon nitride (SiN) or aluminum nitride (AlN). -
Cavity 1000 a is obtained by removing a sacrificial island (not illustrated inFIG. 1 ). The sacrificial island may include silicon oxide. A boundary of the removal of the sacrificial island is defined by a boundary layer 160 (also referred-to as an “etch stop layer”), which is disposed belowpiezoelectric layer 120 and surrounds the sacrificial island before the sacrificial island is removed.Boundary layer 160 may include one or more insulating materials such as silicon (Si), silicon nitride (SiN), aluminum nitride (AlN), polysilicon, or amorphous silicon, or a stacked combination of two or more of those materials. - A first insulating
layer 170 is disposed belowboundary layer 160. A second insulatinglayer 210 is disposed abovebottom cap wafer 200. A metal bonding layer is disposed between first insulatinglayer 170 and second insulatinglayer 210 for bonding first insulatinglayer 170 with second insulatinglayer 210. The metal bonding layer includes at least a firstmetal bonding layer 180 and a secondmetal bonding layer 220. A combination of the materials of firstmetal bonding layer 180 and secondmetal bonding layer 220 may be selected from a group of gold-gold (Au—Au), aluminum-copper (Al—Cu), copper-copper (Cu—Cu), gold-silver (Au—Ag), copper-tin (Cu—Sn), aluminum-germanium (Al—Ge), gold-silicon (Au—Si), gold-germanium (Au—Ge), gold-tin (Au—Sn), copper-tin (Cu—Sn), and gold-indium (Au—In). For example, firstmetal bonding layer 180 may be formed of Au, and secondmetal bonding layer 220 may be formed of Au. Alternatively, firstmetal bonding layer 180 may be formed of Al, and secondmetal bonding layer 220 may be formed of Cu. - A top
electrode contact layer 300 is disposed abovetop passivation layer 195 and is electrically connected totop electrode 190, via a top electrode contact window formed throughtop passivation layer 195. A bottomelectrode contact layer 310 is disposed abovepiezoelectric layer 120 and is electrically connected tobottom electrode 130 via a bottom electrode contact window formed throughpiezoelectric layer 120. Aground contact layer 320 is disposed abovepiezoelectric layer 120 and is electrically connected to firstmetal bonding layer 180 via a contact window formed throughpiezoelectric layer 120,boundary layer 160, and first insulatinglayer 170.Ground contact layer 320 may be connected to ground, such that firstmetal bonding layer 180 is electrically connected to ground. Topelectrode contact layer 300, bottomelectrode contact layer 310, andground contact layer 320 may include various metals, such as aluminum (Al), copper (Cu), gold (Au), titanium (Ti), tungsten (W), platinum (Pt), etc., or a stacked combination of two or more of those metals. -
FIG. 2 is a flow chart of a process of fabricating a FBAR structure according to an embodiment of the present disclosure.FIGS. 3-15 are cross-sectional views of structures formed in steps S1-S13 of the process ofFIG. 2 , according to an embodiment of the present disclosure. - As illustrated in
FIG. 3 , in step S1, asubstrate 100 is obtained. The material of thesubstrate 100 may be silicon (Si), silicon carbide (SiC), or sapphire (Al2O3). - As illustrated in
FIG. 4 , in step S2, abuffer layer 105 is grown onsubstrate 100 by using, for example, a metal organic chemical vapor deposition (MOCVD) process. Next, anepitaxial layer 110 is grown onbuffer layer 105 by using, for example, a MOCVD process. Afterwards,piezoelectric layer 120 is grown onepitaxial layer 110 by using, for example, a physical vapor deposition (PVD) process.Buffer layer 105 may be a single crystal layer, and may be formed of a material having a lattice structure that matches the material ofepitaxial layer 110 orpiezoelectric layer 120. For example,buffer layer 105 may be formed of gallium nitride (GaN), or aluminum nitride (AlN), etc. The purpose ofbuffer layer 105 is to grow a high-quality singlecrystal epitaxial layer 110. Ifepitaxial layer 110 is directly grown onsubstrate 100,epitaxial layer 110 might not have a single crystalline structure due to the lattice mismatch between the materials ofepitaxial layer 110 andsubstrate 100.Epitaxial layer 110 may be formed of a material having a lattice structure that matches the material ofpiezoelectric material layer 120. For example,epitaxial layer 110 may be formed of gallium nitride (GaN), or aluminum nitride (AlN), etc. The purpose ofepitaxial layer 110 is to grow a high-quality singlecrystal piezoelectric layer 120. Thus, according to the embodiments of the present disclosure,piezoelectric layer 120 is grown onepitaxial layer 110, which is grown onbuffer layer 105 grown onsubstrate 100, and the lattice structures of the materials ofbuffer layer 105 andepitaxial layer 110 match each other, and match that ofpiezoelectric layer 120. Therefore,piezoelectric layer 120 formed according to the embodiments of the present disclosure may be a high-quality single crystal structure. - In addition, as illustrated in
FIG. 4 , in step S2, afterpiezoelectric layer 120 is obtained, abottom electrode layer 130 and abottom passivation layer 140 are sequentially deposited onpiezoelectric layer 120. The material ofbottom electrode layer 130 may be any suitable conductive material, such as various metal materials with conductive properties or a stack of several conductive metal materials, such as molybdenum (Mo), aluminum (Al), copper (Cu), platinum (Pt), tantalum (Ta), tungsten (W), palladium (Pd), ruthenium (Ru), etc.Bottom passivation layer 140 may be made of one or more non-conductive materials such as silicon nitride (SiN) and aluminum nitride (AlN). - As illustrated in
FIG. 5 , in step S3,bottom electrode layer 130 andbottom passivation layer 140 are patterned and etched to formbottom electrode 130 and patternedbottom passivation layer 140. The etching process may be a wet chemical etching process, a plasma port etching process, or a combination thereof. This step allows for precise patterning ofbottom electrode 130 of the FBAR structure. - As illustrated in
FIG. 6 , in step S4, asacrificial layer 150 is deposited on the structure illustrated inFIG. 5 .Sacrificial layer 150 is used to formcavity 1000 a of the FBAR structure.Sacrificial layer 150 may include at least one of various types of silicon oxide material, such as pure silicon oxide, phosphor silicate glass (PSG), boron phosphor silicate glass (BPSG), spin on glass (SOG), or fluorinated silicate glass (FSG).Sacrificial layer 150 may be deposited by using a chemical vapor deposition (CVD) process, a physical vapor deposition (PVD) process, or a combination of both. After depositingsacrificial layer 150, a top surface ofsacrificial layer 150 may be planarized and polished by using, for example, a chemical mechanical polishing (CMP) process. - As illustrated in
FIG. 7 , in step S5,sacrificial layer 150 is patterned and etched to form asacrificial island 150 a. The material ofsacrificial island 150 a will be removed in a subsequent release etching process, thereby formingcavity 1000 a of the FBAR structure. The etching process may be a wet chemical etching process, a plasma etching process, or a combination of those two processes. - As illustrated in
FIG. 8 , in step S6,boundary layer 160 is deposited on the structure ofFIG. 7 . A portion ofboundary layer 160 that surroundssacrificial island 150 a functions as an etch stop layer during the subsequent release etching process for removingsacrificial island 150 a to formcavity 1000 a.Boundary layer 160 may include a non-conductive materials such as silicon (Si), silicon nitride (SiN), aluminum nitride (AlN), polysilicon, amorphous silicon, or a stacked combination of two or more of those materials. - As illustrated in
FIG. 9 , in step S7, first insulatinglayer 170 is deposited on the structure illustrated inFIG. 8 . Then, the top surface of first insulatinglayer 170 is planarized and polished. First insulatinglayer 170 may be deposited by using a CVD process, a PVD process, or a combination of those two processes. The material of first insulatinglayer 170 may be silicon oxide (SiO2), or silicon carbide (SiC), etc. The surface planarization and polishing may be performed by using, for example, a CMP process. - As illustrated in
FIG. 10 , in step S8, firstmetal bonding layer 180 is deposited on first insulatinglayer 170. Before the deposition of firstmetal bonding layer 180, metals such as titanium (Ti) and nickel (Ni) may be formed on first insulatinglayer 170 in order to increase the adhesion between first insulatinglayer 170 and firstmetal bonding layer 180. Firstmetal bonding layer 180 may include a material that corresponds to the material of secondmetal bonding layer 220 to achieve metal bonding. A combination of the materials of firstmetal bonding layer 180 and secondmetal bonding layer 220 may be selected from a group of gold-gold (Au—Au), aluminum-copper (Al—Cu), copper-copper (Cu—Cu), gold-silver (Au—Ag), copper-tin (Cu—Sn), aluminum-germanium (Al—Ge), gold-silicon (Au—Si), gold-germanium (Au—Ge), gold-tin (Au—Sn), copper-tin (Cu—Sn), and gold-indium (Au—In). For example, firstmetal bonding layer 180 may be formed of Au, and secondmetal bonding layer 220 may be formed of Au. Alternatively, firstmetal bonding layer 180 may be formed of Al, and secondmetal bonding layer 220 may be formed of Cu. - As illustrated in
FIG. 11 , in step S9,bottom cap wafer 200 is obtained. Second insulatinglayer 210 and secondmetal bonding layer 220 are sequentially deposited onbottom cap wafer 200. Before the deposition of secondmetal bonding layer 220, metals such as titanium (Ti) and nickel (Ni) may be formed on second insulatinglayer 210 in order to increase the adhesion between first insulatinglayer 170 and firstmetal bonding layer 180.Bottom cap wafer 200 may include a material such as silicon (Si), carbon silicon (SiC), aluminum oxide, quartz, glass, or sapphire (Al2O3). Second insulatinglayer 210 may be deposited by using a CVD process, a PVD process, or a combination of those two processes. The material of second insulatinglayer 210 may be silicon oxide (SiO2), or silicon carbide (SiC), etc. As described previously, secondmetal bonding layer 220 may include a material that corresponds to the material of firstmetal bonding layer 180 to achieve metal bonding. A combination of the materials of firstmetal bonding layer 180 and secondmetal bonding layer 220 may be selected from a group of gold-gold (Au—Au), aluminum-copper (Al—Cu), copper-copper (Cu—Cu), gold-silver (Au—Ag), copper-tin (Cu—Sn), aluminum-germanium (Al—Ge), gold-silicon (Au—Si), gold-germanium (Au—Ge), gold-tin (Au—Sn), copper-tin (Cu—Sn), and gold-indium (Au—In). - As illustrated in
FIG. 12 , in step S10, the structure illustrated inFIG. 10 is flipped over, and firstmetal bonding layer 180 and secondmetal bonding layer 220 are bonded together by using a metal bonding process. As a result, the structure formed onbottom cap wafer 200 and the structure formed onsubstrate 100 are combined. The metal bonding process may be achieved by one or more of eutectic bonding, anodic bonding, or thermal compression bonding. - As illustrated in
FIG. 13 , in step S11,substrate 100,buffer layer 105, andepitaxial layer 110 are removed to exposepiezoelectric layer 120. The removal ofsubstrate 100 may be performed by a grinding process. The removal ofbuffer layer 105 andepitaxial layer 110 may be performed by a wet chemical etching process, a plasma dry etching process, or a combination of these two processes. - As illustrated in
FIG. 14 , in step S12, atop electrode layer 190 is deposited onpiezoelectric layer 120, andtop passivation layer 195 is deposited ontop electrode layer 190. The material oftop electrode layer 190 may be any suitable conductive material, such as various metal materials with conductive properties or a stack of several conductive metal materials, such as molybdenum (Mo), aluminum (Al), copper (Cu), platinum (Pt), Tantalum (Ta), tungsten (W), palladium (Pd), ruthenium (Ru), etc. The material oftop passivation layer 195 can be silicon nitride (SiN), aluminum nitride (AlN), silicon oxide (SiO2), silicon oxynitride (SiNO), etc., or a stacked combination of those materials. - As illustrated in
FIG. 15 , in step S13,top electrode layer 190 andtop passivation layer 195 are patterned by etching, to form patternedtop passivation layer 195,top electrode 190. Then, the patternedtop passivation layer 195,piezoelectric layer 120,boundary layer 160, and first insulatinglayer 170 are patterned by etching, for a top electrode contact window exposingtop electrode 190, a bottom electrode contact window exposingbottom electrode 130, and a ground contact window exposing firstmetal contact layer 180. In some embodiments, a different etching sequence may be used to form the contact windows, which is not limited in the present disclosure. For example,passivation layer 195 may be first patterned to form the top electrode contact window; then,piezoelectric layer 120 may be patterned to form the bottom electrode contact window and a part of the ground contact window; and lastly,boundary layer 160 and first insulatinglayer 170 are patterned to form the remaining part of the ground contact window. - Next, top
electrode contact layer 300 is formed in the top electrode contact window to be electrically connected totop electrode 190. Bottomelectrode contact layer 310 is formed in the bottom electrode contact window to be electrically connected tobottom electrode 130.Ground contact layer 320 is formed in the ground contact window to be electrically connected to firstmetal bonding layer 180. The purpose ofground contact layer 320 is to connect firstmetal bonding layer 180 to ground, thereby reducing or eliminating parasitic capacitance introduced by firstmetal bonding layer 180 and secondmetal bonding layer 220. The material of topelectrode contact layer 300, bottomelectrode contact layer 310, andground contact layer 320 may be metal materials, such as aluminum (Al), copper (Cu), gold (Au), titanium (Ti), tungsten (W), platinum (Pt), etc., or a stacked combination of two or more of those materials. - Afterwards,
sacrificial island 150 a is etched and released to formcavity 1000 a by using a release etching process. The etching ofsacrificial island 150 a is stopped atboundary layer 160. The release etching process may be performed by using hydrofluoric acid solution wet etching, buffered oxide etchant (BOE) solution wet etching, or hydrofluoric acid vapor corrosion, or a combination of those processes. As a result,FBAR structure 1000 illustrated inFIG. 1 is formed. - According to the embodiments of the present disclosure, a high-quality single crystal AlN piezoelectric layer can be obtained by growing a GaN epitaxial layer on a silicon wafer, and then growing the AlN piezoelectric layer on the GaN epitaxial layer. The high-quality single crystal AlN piezoelectric layer improves the heat dissipation efficiency of a bulk acoustic wave resonator including the same. At the same time, the metal bonding method was selected to overcome the difficulty in bonding caused by the wafer warpage as a result of the introduction of gallium nitride epitaxial layer. In addition, the metal bonding layer is grounded in order to avoid the negative impact of the metal bonding layer on the performance.
- Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
Claims (20)
1. A film bulk acoustic resonator (FBAR) structure, comprising:
a bottom cap wafer;
a piezoelectric layer disposed on the bottom cap wafer, the piezoelectric layer including a single crystalline piezoelectric material;
a bottom electrode disposed below the piezoelectric layer;
a top electrode disposed above the piezoelectric layer; and
a cavity disposed below the bottom electrode.
2. The FBAR structure of claim 1 , wherein the single crystalline piezoelectric material has a crystallinity of less than 0.5 degrees at Full Width Half Maximum (FWHM) measured using X-ray diffraction (XRD).
3. The FBAR structure of claim 1 , wherein the single crystalline piezoelectric material includes aluminum nitride (AlN), aluminum nitride doped with scandium (ScAlN), zinc oxide (ZnO), or lead zirconate titanate (PZT).
4. The FBAR structure of claim 1 , further comprising:
a first insulating layer disposed below the cavity;
a second insulating layer disposed above the bottom cap wafer; and
a metal bonding layer bonding the first insulating layer with the second insulating layer.
5. The FBAR structure of claim 4 , wherein the metal bonding layer includes at least a first metal bonding layer and a second metal bonding layer.
6. The FBAR structure of claim 5 , wherein a combination of materials of the first metal bonding layer and the second metal bonding layer is selected from a group of gold-gold (Au—Au), aluminum-copper (Al—Cu), copper-copper (Cu—Cu), gold-silver (Au—Ag), copper-tin (Cu—Sn), aluminum-germanium (Al—Ge), gold-silicon (Au—Si), gold-germanium (Au—Ge), gold-tin (Au—Sn), copper-tin (Cu—Sn), and gold-indium (Au—In).
7. The FBAR structure of claim 4 , further comprising a ground contact layer electrically connecting the metal bonding layer to ground.
8. The FBAR structure of claim 7 , further comprising a ground contact window formed in the first insulating layer and the piezoelectric layer, and exposing the metal bonding layer,
wherein the ground contact layer is electrically connected to the metal bonding layer via the ground contact window.
9. The FBAR structure of claim 4 , wherein the first insulating layer and the second insulating layer include silicon oxide (SiO2) or silicon carbide (SiC).
10. The FBAR structure of claim 1 , further comprising:
a top passivation layer disposed above the top electrode; and
a bottom passivation layer disposed below the bottom electrode.
11. The FBAR structure of claim 10 , wherein the top passivation layer and the bottom passivation layer include silicon nitride (SiN) or aluminum nitride (AlN).
12. The FBAR structure of claim 1 , further comprising a boundary layer surrounding the cavity.
13. The FBAR structure of claim 12 , wherein the boundary layer includes silicon (Si), silicon nitride (SiN), aluminum nitride (AlN), polysilicon, amorphous silicon, or a stacked combination of two or more of those materials.
14. The FBAR structure of claim 1 , further comprising:
a bottom electrode contact layer electrically connected with the bottom electrode; and
a top electrode contact layer electrically connected with the top electrode.
15. The FBAR structure of claim 14 , further comprising:
a bottom electrode contact window formed in the piezoelectric layer and exposing the bottom electrode,
wherein the bottom electrode contact layer is electrically connected with the bottom electrode via the bottom electrode contact window.
16. The FBAR structure of claim 14 , wherein each one of the bottom electrode contact layer and the top electrode contact layer includes aluminum (Al), copper (Cu), gold (Au), titanium (Ti), tungsten (W), platinum (Pt), or a stacked combination of two or more of those materials.
17. The FBAR structure of claim 1 , wherein each one of the top electrode and the bottom electrode includes molybdenum (Mo), aluminum (Al), copper (Cu), platinum (Pt), tantalum (Ta), tungsten (W), palladium (Pd), ruthenium (Ru), or a stacked combination of two or more of those materials.
18. The FBAR structure of claim 1 , wherein the bottom cap wafer includes silicon (Si), silicon carbide (SiC), sapphire (Al2O3), or a stacked combination of two or more of those materials.
19. The FBAR structure of claim 1 , wherein a projection of at least one edge of the top electrode is located within the cavity.
20. The FBAR structure of claim 1 , wherein a projection of at least one side of the bottom electrode is located within the cavity.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US17/563,630 US20220131527A1 (en) | 2021-12-28 | 2021-12-28 | Fbar structure having single crystalline piezoelectric layer and fabricating method thereof |
US17/649,476 US11545958B2 (en) | 2021-12-28 | 2022-01-31 | FBAR structure having single crystalline piezoelectric layer and fabricating method thereof |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US17/563,630 US20220131527A1 (en) | 2021-12-28 | 2021-12-28 | Fbar structure having single crystalline piezoelectric layer and fabricating method thereof |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US17/649,476 Continuation US11545958B2 (en) | 2021-12-28 | 2022-01-31 | FBAR structure having single crystalline piezoelectric layer and fabricating method thereof |
Publications (1)
Publication Number | Publication Date |
---|---|
US20220131527A1 true US20220131527A1 (en) | 2022-04-28 |
Family
ID=81257200
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US17/563,630 Pending US20220131527A1 (en) | 2021-12-28 | 2021-12-28 | Fbar structure having single crystalline piezoelectric layer and fabricating method thereof |
US17/649,476 Active US11545958B2 (en) | 2021-12-28 | 2022-01-31 | FBAR structure having single crystalline piezoelectric layer and fabricating method thereof |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US17/649,476 Active US11545958B2 (en) | 2021-12-28 | 2022-01-31 | FBAR structure having single crystalline piezoelectric layer and fabricating method thereof |
Country Status (1)
Country | Link |
---|---|
US (2) | US20220131527A1 (en) |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3944161B2 (en) * | 2003-12-25 | 2007-07-11 | 株式会社東芝 | Thin film bulk acoustic wave resonator and manufacturing method of thin film bulk acoustic wave resonator |
JP4744849B2 (en) * | 2004-11-11 | 2011-08-10 | 株式会社東芝 | Semiconductor device |
US10804877B2 (en) * | 2014-01-21 | 2020-10-13 | Avago Technologies International Sales Pte. Limited | Film bulk acoustic wave resonator (FBAR) having stress-relief |
CN105590869A (en) * | 2014-10-24 | 2016-05-18 | 中芯国际集成电路制造(上海)有限公司 | Semiconductor device and manufacturing method thereof |
KR102369436B1 (en) * | 2017-04-19 | 2022-03-03 | 삼성전기주식회사 | Bulk acoustic wave resonator |
CN107342748B (en) | 2017-07-04 | 2020-04-28 | 浙江大学 | Bulk acoustic wave resonator based on single crystal piezoelectric film and preparation method thereof |
US11437561B2 (en) * | 2018-11-29 | 2022-09-06 | Samsung Electro-Mechanics Co., Ltd. | Acoustic resonator |
US11424732B2 (en) * | 2018-12-28 | 2022-08-23 | Skyworks Global Pte. Ltd. | Acoustic wave devices with common ceramic substrate |
US20200313648A1 (en) | 2019-03-28 | 2020-10-01 | Global Communication Semiconductors, Llc | Single-Crystal Bulk Acoustic Wave Resonator and Method of Making Thereof |
US11063571B2 (en) | 2019-07-25 | 2021-07-13 | Zhuhai Crystal Resonance Technologies Co., Ltd. | Packaged electronic components |
CN113572448B (en) | 2021-09-23 | 2021-12-17 | 深圳新声半导体有限公司 | Bulk acoustic wave resonator |
-
2021
- 2021-12-28 US US17/563,630 patent/US20220131527A1/en active Pending
-
2022
- 2022-01-31 US US17/649,476 patent/US11545958B2/en active Active
Also Published As
Publication number | Publication date |
---|---|
US11545958B2 (en) | 2023-01-03 |
US20220158617A1 (en) | 2022-05-19 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20220103147A1 (en) | Lithium niobate or lithium tantalate fbar structure and fabricating method thereof | |
US7802349B2 (en) | Manufacturing process for thin film bulk acoustic resonator (FBAR) filters | |
US11671067B2 (en) | Piezoelectric acoustic resonator manufactured with piezoelectric thin film transfer process | |
KR20170073063A (en) | Acoustic resonator and method for manufacturing same | |
CN110719082B (en) | Acoustic wave resonator package | |
US20240164216A1 (en) | Methods of forming group iii piezoelectric thin films via removal of portions of first sputtered material | |
US11646710B2 (en) | Piezoelectric acoustic resonator manufactured with piezoelectric thin film transfer process | |
US11895920B2 (en) | Methods of forming group III piezoelectric thin films via removal of portions of first sputtered material | |
US20230011477A1 (en) | Structure and manufacturing method of surface acoustic wave filter with back electrode of piezoelectric layer | |
US20230008078A1 (en) | Structure and manufacturing method of surface acoustic wave filter with back electrode of piezoelectric layer | |
US11832521B2 (en) | Methods of forming group III-nitride single crystal piezoelectric thin films using ordered deposition and stress neutral template layers | |
US11677381B2 (en) | Film bulk acoustic resonator structure and fabricating method | |
US11856858B2 (en) | Methods of forming doped crystalline piezoelectric thin films via MOCVD and related doped crystalline piezoelectric thin films | |
TW202135463A (en) | Acoustic wave device and manufacturing method for the same | |
US20240162875A1 (en) | Bulk acoustic wave resonator and fabrication method thereof | |
US11533039B2 (en) | Lithium niobate or lithium tantalate FBAR structure and fabricating method thereof | |
US11545958B2 (en) | FBAR structure having single crystalline piezoelectric layer and fabricating method thereof | |
US11699987B2 (en) | Bulk acoustic wave resonator and fabrication method thereof | |
CN114465597A (en) | Bulk acoustic wave resonator | |
US20230091476A1 (en) | Bulk acoustic wave resonator with metal bonding layer | |
US20230084598A1 (en) | Bulk acoustic wave resonator with metal bonding layer | |
TWI833158B (en) | Acoustic resonator | |
US11689171B2 (en) | Bulk acoustic wave resonator and fabrication method thereof | |
CN113872549B (en) | Method for manufacturing bulk acoustic wave resonator, bulk acoustic wave resonator and filter | |
US20220103146A1 (en) | Film bulk acoustic resonator structure and fabricating method |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: NEWSONIC TECHNOLOGIES, CHINA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:WANG, JIAN;REEL/FRAME:058491/0790 Effective date: 20211220 |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION |