CN113839637A - Preparation method of monocrystal film bulk acoustic resonator with electrode ring groove and strip-shaped bulges - Google Patents
Preparation method of monocrystal film bulk acoustic resonator with electrode ring groove and strip-shaped bulges Download PDFInfo
- Publication number
- CN113839637A CN113839637A CN202110986873.4A CN202110986873A CN113839637A CN 113839637 A CN113839637 A CN 113839637A CN 202110986873 A CN202110986873 A CN 202110986873A CN 113839637 A CN113839637 A CN 113839637A
- Authority
- CN
- China
- Prior art keywords
- layer
- strip
- electrode
- thickness
- ring groove
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000002360 preparation method Methods 0.000 title claims abstract description 11
- 239000010410 layer Substances 0.000 claims abstract description 128
- 238000000151 deposition Methods 0.000 claims abstract description 31
- 239000000758 substrate Substances 0.000 claims abstract description 30
- 239000011241 protective layer Substances 0.000 claims abstract description 17
- 238000000034 method Methods 0.000 claims description 42
- 239000013078 crystal Substances 0.000 claims description 18
- 238000001039 wet etching Methods 0.000 claims description 17
- 229910052751 metal Inorganic materials 0.000 claims description 16
- 239000002184 metal Substances 0.000 claims description 16
- 238000000059 patterning Methods 0.000 claims description 15
- 238000001020 plasma etching Methods 0.000 claims description 14
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 7
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 6
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 6
- 229910052710 silicon Inorganic materials 0.000 claims description 6
- 239000010703 silicon Substances 0.000 claims description 6
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 4
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 4
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 4
- 229910021417 amorphous silicon Inorganic materials 0.000 claims description 3
- 238000001312 dry etching Methods 0.000 claims description 3
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims description 3
- 238000005406 washing Methods 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 claims description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 2
- 229910021486 amorphous silicon dioxide Inorganic materials 0.000 claims description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 2
- 239000001569 carbon dioxide Substances 0.000 claims description 2
- 230000008021 deposition Effects 0.000 claims description 2
- 238000005516 engineering process Methods 0.000 claims description 2
- 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 2
- 229910052451 lead zirconate titanate Inorganic materials 0.000 claims description 2
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 claims description 2
- 229910052750 molybdenum Inorganic materials 0.000 claims description 2
- 239000011733 molybdenum Substances 0.000 claims description 2
- 235000012239 silicon dioxide Nutrition 0.000 claims description 2
- 239000000377 silicon dioxide Substances 0.000 claims description 2
- 239000011787 zinc oxide Substances 0.000 claims description 2
- 239000010409 thin film Substances 0.000 claims 8
- 239000010408 film Substances 0.000 claims 1
- 239000006185 dispersion Substances 0.000 description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- 238000005229 chemical vapour deposition Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000004518 low pressure chemical vapour deposition Methods 0.000 description 4
- 238000001755 magnetron sputter deposition Methods 0.000 description 4
- 238000002207 thermal evaporation Methods 0.000 description 4
- 238000005498 polishing Methods 0.000 description 2
- 229920005591 polysilicon Polymers 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 150000002902 organometallic compounds Chemical class 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—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
- H03H9/02047—Treatment of substrates
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
- H03H2003/023—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks the resonators or networks being of the membrane type
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
The invention discloses a preparation method of a monocrystal film bulk acoustic resonator with electrode ring grooves and strip-shaped bulges, which comprises the following steps: sequentially depositing a stripping layer and a piezoelectric layer on a substrate, depositing a lower electrode on the piezoelectric layer, preparing an annular groove on the lower electrode, depositing two strip-shaped bulges and a sacrificial layer wrapping the two strip-shaped bulges, depositing a protective layer wrapping the sacrificial layer on the piezoelectric layer, and depositing a second layer to be bonded wrapping the protective layer on the piezoelectric layer; then, bonding a layer I to be bonded on the substrate with a layer II to be bonded, removing the stripping layer and the substrate, depositing an upper electrode on the piezoelectric layer, preparing a ring groove on the upper electrode and depositing two strip-shaped bulges; and finally, forming a through hole on the piezoelectric layer, opening the bottom of the through hole on the surface of the sacrificial layer, and removing the sacrificial layer by using the through hole to form a cavity. According to the invention, the lower annular groove, the lower strip-shaped bulge I and the lower strip-shaped bulge II are arranged on the lower electrode of the resonator, and the upper annular groove, the upper strip-shaped bulge I and the upper strip-shaped bulge II are arranged on the upper electrode, so that the frequency and the Q value of the resonator are improved.
Description
Technical Field
The invention relates to a film bulk acoustic resonator, in particular to a preparation method of a monocrystal film bulk acoustic resonator with electrode ring grooves and strip-shaped bulges.
Background
Compared with a polycrystalline film, the single crystal piezoelectric film can be used for preparing a film bulk acoustic resonator with higher frequency and Q value, so that researchers are more inclined to apply the single crystal piezoelectric film to the film bulk acoustic resonator for research. However, since the preparation process of the single crystal film bulk acoustic resonator is relatively difficult, if the conventional structure and shape of the upper electrode are changed, the frequency and Q value of the film bulk acoustic resonator are further improved by adopting the upper electrode with a complex structure, which brings a serious challenge to the preparation process, the process level in China at present is difficult to keep up with the design of the upper electrode structure which is continuously complicated, and the economic benefit brought by the research is very limited, which is obviously unsustainable. Therefore, how to prepare the film bulk acoustic resonator with higher frequency and Q value by a simple preparation process on the premise of ensuring the simple structure of the upper electrode is a research direction for breaking through the performance of the film bulk acoustic resonator in the future.
Disclosure of Invention
The invention aims to provide a preparation method of a single crystal film bulk acoustic resonator with an electrode ring groove and strip-shaped bulges.
The invention is realized by adopting the following technical scheme:
the invention relates to a preparation method of a monocrystal film bulk acoustic resonator with electrode ring grooves and strip-shaped bulges, which comprises the following steps:
s1: both the substrate and the base were subjected to ultrasonic water washing.
S2: depositing a release layer on one side of the substrate; then preparing a piezoelectric layer on the peeling layer; and depositing a first layer to be bonded on one side of the substrate, and flattening the first layer to be bonded.
S3: depositing metal on the surface of the piezoelectric layer and patterning to form a lower electrode; forming a lower annular groove on the surface of the lower electrode by adopting a plasma etching or wet etching process, and then depositing and patterning metal on the surface of the lower electrode, which is positioned at two sides of the outer edge of the lower annular groove, to form a first lower strip-shaped bulge and a second lower strip-shaped bulge; the transverse width and the thickness of the first lower strip-shaped bulge and the second lower strip-shaped bulge are equal; then, forming a sacrificial layer wrapping the lower electrode, the lower ring groove, the first lower strip-shaped bulges and the second lower strip-shaped bulges on the surface of the piezoelectric layer through deposition and patterning; then, depositing a protective layer wrapping the sacrificial layer on the surface of the piezoelectric layer; and finally, depositing a second layer to be bonded wrapping the protective layer on the surface of the piezoelectric layer, and flattening the surface of the second layer to be bonded.
S4: connecting a first layer to be bonded on the substrate with a second layer to be bonded through a bonding process; then, removing the stripping layer and the substrate by adopting a laser stripping technology, and flattening the surface of the piezoelectric layer; then, depositing metal on the surface of the piezoelectric layer where the peeling layer and the substrate are removed and patterning to form an upper electrode; then, forming an upper ring groove on the surface of the upper electrode by adopting a plasma etching or wet etching process; finally, depositing metal on the surface of the upper electrode at two sides of the outer edge of the upper ring groove and patterning the metal to form a first upper strip-shaped bulge and a second upper strip-shaped bulge; the transverse width and the thickness of the first upper strip-shaped bulge and the second upper strip-shaped bulge are equal.
S5: forming a through hole on the piezoelectric layer by adopting a plasma etching or wet etching process, wherein the bottom of the through hole is opened on the surface of the sacrificial layer; then, the sacrificial layer is removed by a wet etching process or a dry etching process using the through hole, thereby forming a cavity between the lower electrode and the protective layer.
Preferably, the piezoelectric layer is made of one or more of single crystal aluminum nitride, polycrystalline aluminum nitride, zinc oxide, single crystal lithium tantalate, lead zirconate titanate and lithium niobate in any proportion, the thickness is 10nm-4000nm, and the transverse width is 180 μm-250 μm.
Preferably, the material of the first layer to be bonded and the material of the second layer to be bonded are both one or two of silicon oxide and silicon in any proportion, and the thickness of the first layer to be bonded and the second layer to be bonded are both 0.1-10 μm.
Preferably, the lower electrode has a thickness of 50nm to 500nm and a lateral width of 30 to 240 μm.
Preferably, the thickness of the upper electrode is 50nm-500nm, the lateral width is 30-240 μm, and both the thickness and the lateral width of the upper electrode are smaller than those of the lower electrode.
Preferably, the sacrificial layer is made of one or two of polysilicon, amorphous silicon, silicon dioxide and doped carbon dioxide according to any proportion; the thickness of the sacrificial layer is 0.5-3 μm, and the lateral width is 20-230 μm.
Preferably, the depth and the transverse width of the lower ring groove and the upper ring groove are equal, the depth is 20nm-200nm, and the transverse width is more than 0 μm and less than 10 μm; the thickness and the transverse width of the lower strip-shaped bulge I, the lower strip-shaped bulge II, the upper strip-shaped bulge I and the upper strip-shaped bulge II are equal, the thickness is 50nm-300nm, and the transverse width is 0.5 mu m-10 mu m.
Preferably, the substrate has a thickness of 500 μm; the thickness of the first layer to be bonded and the thickness of the second layer to be bonded are both 5 micrometers; the thickness of the protective layer is 1 μm, and the transverse width is 190 μm; the thickness of the lower electrode is 180nm, and the transverse width of the lower electrode is 170 mu m; the thickness of the piezoelectric layer is 700nm, and the transverse width of the piezoelectric layer is 200 μm; the thickness of the upper electrode is 140nm, and the transverse width is 150 mu m; the transverse width of the cavity is 180 mu m, and the thickness of the cavity is 2 mu m; the depth of the lower ring groove and the depth of the upper ring groove are both 100nm, and the transverse width of the lower ring groove and the transverse width of the upper ring groove are both 3.2 mu m; the thickness of the lower strip-shaped bulge I, the thickness of the lower strip-shaped bulge II, the thickness of the upper strip-shaped bulge I and the thickness of the upper strip-shaped bulge II are all 200nm, and the transverse width of each of the lower strip-shaped bulge I, the lower strip-shaped bulge II, the upper strip-shaped bulge I and the upper strip-shaped bulge II is 2.7 mu m.
More preferably, the substrate, the first layer to be bonded and the second layer to be bonded are made of silicon, the piezoelectric layer and the protective layer are made of aluminum nitride, and the upper electrode and the lower electrode are made of molybdenum.
The invention has the following beneficial effects:
the lower electrode of the resonator prepared by the invention is provided with the lower annular groove, the first lower strip-shaped bulge and the second lower strip-shaped bulge, and the upper electrode is provided with the upper annular groove, the first upper strip-shaped bulge and the second upper strip-shaped bulge, so that the problem of main resonance sound wave leakage of the resonator can be optimized on the premise of ensuring that the structures of the upper electrode and the lower electrode are simple. Because the area of the single crystal film bulk acoustic resonator is limited and the sound velocity of various materials is different, dispersion can be inevitably generated (the resonator prepared by the invention belongs to a film cavity type resonator, the dispersion type is II type), but the thickness of the electrode at the edge of an effective area is thinner by adding a concave structure (a lower ring groove and an upper ring groove) at the edge of the effective area (namely the overlapping area of an upper electrode and a lower electrode), and clutter of the II type dispersion between series-parallel resonance can be transferred to the outside of a parallel resonance frequency point, thereby reducing clutter influence. Further, the lower strip-shaped protrusion I, the lower strip-shaped protrusion, the upper strip-shaped protrusion I and the upper strip-shaped protrusion II can optimize negative effects brought by edge recession, such as the effects of unsmooth impedance curve and low Q value, and inhibit leakage of main resonance sound wave energy. Therefore, the lower ring groove, the lower strip-shaped bulge I and the lower strip-shaped bulge are arranged on the lower electrode of the resonator, the upper ring groove, the upper strip-shaped bulge I and the upper strip-shaped bulge II are arranged on the upper electrode, noise wave energy can be limited in the resonator while clutter influence is reduced, leakage is reduced, and the frequency and the Q value of the resonator are improved.
Drawings
FIG. 1 is a cross-sectional view of the present invention preparing a lift-off layer on a substrate and a piezoelectric layer on the lift-off layer.
Fig. 2 is a cross-sectional view of a first layer to be bonded on a substrate.
Fig. 3 is a cross-sectional view of a lower electrode, a lower ring groove, a first lower strip-shaped protrusion, a second lower strip-shaped protrusion, a sacrificial layer, a protective layer and a second layer to be bonded, which are prepared on the structure of fig. 1.
Fig. 4 is a cross-sectional view of the structure of fig. 2 and the structure of fig. 3 after bonding and molding, removing the peeling layer and the substrate, and preparing an upper electrode, an upper ring groove, a first upper strip-shaped protrusion and a second upper strip-shaped protrusion on the piezoelectric layer.
FIG. 5 is a cross-sectional view of the fabrication of a via in the structure of FIG. 4 and the removal of the sacrificial layer to form a cavity.
Fig. 6 is a graph plotting the Q-value of a resonator at a series resonant frequency point as a function of the lateral width of the lower and upper ring grooves using a particular set of structural dimensions in accordance with the present invention.
Fig. 7 is a graph plotting Q at parallel resonant frequency points for a resonator as a function of the lateral widths of the lower and upper ring slots using a particular set of structural dimensions in accordance with the present invention.
Fig. 8 is a graph plotting the Q-value of the resonator at the point of the series resonance frequency as a function of the lateral width of the lower strip-shaped projection one, the lower strip-shaped projection two, the upper strip-shaped projection one, and the upper strip-shaped projection two using a specific set of structural dimensions in accordance with the present invention.
Fig. 9 is a graph plotting the Q value of the resonator at the parallel resonance frequency point as a function of the lateral width of the lower strip-shaped protrusion one, the lower strip-shaped protrusion two, the upper strip-shaped protrusion one, and the upper strip-shaped protrusion two using a specific set of structural dimensions.
Detailed Description
The invention will be further explained with reference to the drawings.
The preparation method of the monocrystal film bulk acoustic resonator with the electrode ring groove and the strip-shaped bulges comprises the following specific steps:
s1: ultrasonic water washing is performed on both the substrate 100 and the base 108; the substrate and the base are made of one or more of glass, silicon carbide, silicon nitride or ceramic according to any proportion.
S2: as shown in fig. 1, a lift-off layer 113 is deposited on the substrate 100 side by a metal organic chemical vapor deposition process (MOCVD); the material of the peeling layer 113 is GaN; a piezoelectric layer 101 is then prepared (which may be deposited using a metal organic chemical vapor deposition process) on the lift-off layer 113 to a thickness of 10nm to 4000 nm. As shown in fig. 2, a first layer 109 to be bonded is deposited on one side of a substrate 108 by a Low Pressure Chemical Vapor Deposition (LPCVD) process, and the surface of the first layer 109 to be bonded is planarized by chemical mechanical polishing, wherein the first layer 109 to be bonded is made of one or a combination of silicon oxide and silicon according to any ratio, and has a thickness of 0.1-10 μm.
S3: as shown in fig. 3, depositing a metal on the surface of the piezoelectric layer 101 by thermal evaporation or magnetron sputtering, and patterning by plasma or wet etching to form a lower electrode 102; forming a lower annular groove 103 on the surface of the lower electrode 102 by adopting a plasma etching or wet etching process, depositing metal on the two sides of the surface of the lower electrode 102, which are positioned at the outer edge of the lower annular groove 103, by adopting a thermal evaporation or magnetron sputtering method, and patterning by adopting a plasma or wet etching method to form a first lower strip-shaped bulge 104a and a second lower strip-shaped bulge 104 b; the transverse width and the thickness of the first lower strip-shaped bulges 104a and the second lower strip-shaped bulges 104b are equal, the transverse width is within the range of 0.5-10 mu m, and the thickness is within the range of 50-300 nm. Then, polysilicon or amorphous silicon is deposited on the surface of the piezoelectric layer 101 by using a plasma chemical vapor deposition process, and patterning is performed by using a plasma or wet etching method, so as to form a sacrificial layer 105 wrapping the lower electrode 102, the lower annular groove 103, the first lower strip-shaped protrusion 104a and the second lower strip-shaped protrusion 104 b. Then, depositing a protective layer 106 wrapping the sacrificial layer 105 on the surface of the piezoelectric layer 101 by using a metal organic compound chemical vapor deposition process; and finally, depositing a second layer 107 to be bonded wrapping the protective layer 106 on the surface of the piezoelectric layer 101 by using a Low Pressure Chemical Vapor Deposition (LPCVD) process, and flattening the surface of the second layer 107 to be bonded by using a chemical mechanical polishing mode, wherein the second layer 107 to be bonded is made of one or two of silicon oxide and silicon according to any proportion.
S4: as shown in fig. 4, a first layer 109 to be bonded on a substrate 108 is attached to a second layer 107 to be bonded, and is connected by a bonding process, so that a dense interface is formed between the first layer 109 to be bonded and the second layer 107 to be bonded. Then, the peeling layer 113 and the substrate 100 are removed by a laser peeling technique, and the surface of the piezoelectric layer 101 is planarized. Then, depositing metal on the surface of the piezoelectric layer 101, where the peeling layer 113 and the substrate 100 are removed, by using a thermal evaporation or magnetron sputtering method, and patterning by using a plasma or wet etching method to form an upper electrode 110; then, an upper ring groove 111 is formed on the surface of the upper electrode 110 by adopting a plasma etching or wet etching process; finally, depositing metal on the surface of the upper electrode 110 at two sides of the outer edge of the upper ring groove 111 by adopting a thermal evaporation or magnetron sputtering method, and patterning by adopting a plasma or wet etching method to form a first upper strip-shaped protrusion 112a and a second upper strip-shaped protrusion 112 b; the transverse width and the thickness of the upper strip-shaped bulge I112 a and the transverse width and the thickness of the upper strip-shaped bulge II 112b are equal, the transverse width is within the range of 0.5-10 mu m, and the thickness is within the range of 50-300 nm.
S5: as shown in fig. 5, a through hole is formed on the piezoelectric layer 101 by using a plasma etching or wet etching process, and the bottom of the through hole is opened on the surface of the sacrificial layer 105; then, the sacrificial layer 105 is removed by a wet etching process or a dry etching process using a via hole, thereby forming a cavity 105a between the lower electrode 102 and the protective layer 106.
The upper electrode and the lower electrode of the resonator prepared by the invention have completely consistent structures, the lower electrode is provided with a lower annular groove, a first lower strip-shaped bulge 103 and a second lower strip-shaped bulge 104, and the upper electrode is provided with an upper annular groove, a first upper strip-shaped bulge 111 and a second upper strip-shaped bulge 112, so that the problem of main resonance sound wave leakage of the resonator can be optimized on the premise of ensuring that the structures of the upper electrode and the lower electrode are simple. Because the area of the single crystal film bulk acoustic resonator is limited and the sound velocity of various materials is different, dispersion can be inevitably generated (the resonator prepared by the invention belongs to a film cavity type resonator, the dispersion type is II type), but the thickness of the electrode at the edge of an effective area is thinner by adding a concave structure (a lower ring groove and an upper ring groove) at the edge of the effective area (namely the overlapping area of an upper electrode and a lower electrode), and clutter of the II type dispersion between series-parallel resonance can be transferred to the outside of a parallel resonance frequency point, thereby reducing clutter influence. Further, the first lower strip-shaped protrusion 103, the second lower strip-shaped protrusion 104, the first upper strip-shaped protrusion 111 and the second upper strip-shaped protrusion 112 of the present invention can optimize negative effects caused by edge sag, such as the effects of uneven impedance curve and low Q value, and suppress leakage of the primary resonance acoustic wave energy. Therefore, the lower ring groove, the first lower strip-shaped bulge 103 and the second lower strip-shaped bulge 104 are arranged on the lower electrode of the resonator, the upper ring groove, the first upper strip-shaped bulge 111 and the second upper strip-shaped bulge 112 are arranged on the upper electrode, noise wave energy can be limited in the resonator while clutter influence is reduced, leakage is reduced, and the Q value of the resonator is improved.
A specific set of structural dimensions is given below:
the substrate 108 (using Si) is 500 μm thick; the thickness of the first layer to be bonded and the thickness of the second layer to be bonded (adopting Si) are both 5 mu m; the thickness of the protective layer (AlN) (the thickness of the part covering the sacrificial layer except the side wall part of the sacrificial layer is counted) is 1 μm, and the transverse width is 190 μm; the thickness of the lower electrode (adopting Mo) is 180 nm; the thickness of the piezoelectric layer (AlN is adopted) is 700nm, and the transverse width is 200 mu m; the thickness of the upper electrode (adopting Mo) is 140 nm; the transverse width of the cavity is 180 mu m, and the thickness of the cavity is 2 mu m; the depths of the lower ring groove and the upper ring groove are both 100 nm.
Setting the transverse widths of the lower ring groove and the upper ring groove to be L1, and setting the transverse widths of the lower strip-shaped protrusion I104 a, the lower strip-shaped protrusion II 104b, the upper strip-shaped protrusion I111 and the upper strip-shaped protrusion II 112 to be L2; the Q value curve at the series resonance frequency point and the Q value curve at the parallel resonance frequency point, which are varied with the lateral width L1, are plotted using the above-described specific set of structural dimensions for the resonator in the case where only the lower ring groove and the upper ring groove are provided without the lower first strip-like projection 104a, the lower second strip-like projection 104b, the upper first strip-like projection 111, and the upper second strip-like projection 112, and the lateral width of the lower electrode is 164 μm and the lateral width of the upper electrode is 144 μm, as shown in fig. 6 and 7, respectively. When the lateral widths of the lower ring groove and the upper ring groove of the resonator are all 3.2 μm, the thicknesses of the lower strip-shaped protrusion one 104a, the lower strip-shaped protrusion two 104b, the upper strip-shaped protrusion one 111 and the upper strip-shaped protrusion two 112 of the resonator are all 200nm, the lateral width of the lower electrode is 170 μm, and the lateral width of the upper electrode is 150 μm (since the strip-shaped protrusions are prepared on the outer edge of the lower ring groove or the upper ring groove, both sides of the lateral widths of the upper electrode and the lower electrode need to be widened by about 3 μm, and after the widening, the Q value of the resonator is also changed), a Q value curve at a series resonance frequency point and a Q value curve at a parallel resonance frequency point, which are changed along with the lateral width L2, are respectively shown in fig. 8 and 9. As can be seen from fig. 6, when the lateral width L1 is 0 μm, i.e., the lower ring groove and the upper ring groove are not provided, the Q value (Qs) at the series resonance frequency point of the resonator is small and is 920; when the lateral width L1 is 3.5 μm, the Q value (Qs) at the series resonance frequency point of the resonator is maximum, 1260. As can be seen from fig. 7, when the lateral width L1 is 0 μm, the Q value (Qp) at the parallel resonance frequency point of the resonator is small, 835; when the lateral width L1 is 3.2 μm, the Q value (Qp) at the parallel resonance frequency point of the resonator is the largest, 1162. As can be seen from fig. 8, when the lateral width L2 is 0 μm, that is, the lower first strip-shaped protrusion 104a, the lower second strip-shaped protrusion 104b, the upper first strip-shaped protrusion 111, and the upper second strip-shaped protrusion 112 are not provided, the Q value (Qs) at the series resonance frequency point of the resonator is small, 1104; when the lateral width L2 is 1 μm, the Q value (Qs) at the series resonance frequency point of the resonator is maximum at 1430. As can be seen from fig. 9, when the lateral width L2 is 0 μm, the Q value (Qp) at the parallel resonance frequency point of the resonator is small, 1005; when the lateral width L2 is 2.7 μm, the Q value (Qp) at the parallel resonance frequency point of the resonator is the largest, and 1286 is obtained.
Claims (9)
1. The preparation method of the monocrystal film bulk acoustic resonator with the electrode ring groove and the strip-shaped bulges is characterized by comprising the following steps of: the method comprises the following specific steps:
s1: carrying out ultrasonic water washing on the substrate and the base;
s2: depositing a release layer on one side of the substrate; then preparing a piezoelectric layer on the peeling layer; depositing a first layer to be bonded on one side of the substrate, and flattening the first layer to be bonded;
s3: depositing metal on the surface of the piezoelectric layer and patterning to form a lower electrode; forming a lower annular groove on the surface of the lower electrode by adopting a plasma etching or wet etching process, and then depositing and patterning metal on the surface of the lower electrode, which is positioned at two sides of the outer edge of the lower annular groove, to form a first lower strip-shaped bulge and a second lower strip-shaped bulge; the transverse width and the thickness of the first lower strip-shaped bulge and the second lower strip-shaped bulge are equal; then, forming a sacrificial layer wrapping the lower electrode, the lower ring groove, the first lower strip-shaped bulges and the second lower strip-shaped bulges on the surface of the piezoelectric layer through deposition and patterning; then, depositing a protective layer wrapping the sacrificial layer on the surface of the piezoelectric layer; finally, depositing a second layer to be bonded wrapping the protective layer on the surface of the piezoelectric layer, and flattening the surface of the second layer to be bonded;
s4: connecting a first layer to be bonded on the substrate with a second layer to be bonded through a bonding process; then, removing the stripping layer and the substrate by adopting a laser stripping technology, and flattening the surface of the piezoelectric layer; then, depositing metal on the surface of the piezoelectric layer where the peeling layer and the substrate are removed and patterning to form an upper electrode; then, forming an upper ring groove on the surface of the upper electrode by adopting a plasma etching or wet etching process; finally, depositing metal on the surface of the upper electrode at two sides of the outer edge of the upper ring groove and patterning the metal to form a first upper strip-shaped bulge and a second upper strip-shaped bulge; the transverse width and the thickness of the first upper strip-shaped bulge and the second upper strip-shaped bulge are equal;
s5: forming a through hole on the piezoelectric layer by adopting a plasma etching or wet etching process, wherein the bottom of the through hole is opened on the surface of the sacrificial layer; then, the sacrificial layer is removed by a wet etching process or a dry etching process using the through hole, thereby forming a cavity between the lower electrode and the protective layer.
2. The method for manufacturing a single crystal thin film bulk acoustic resonator with an electrode having a ring groove and a stripe-shaped protrusion according to claim 1, comprising: the piezoelectric layer is made of one or more of single crystal aluminum nitride, polycrystalline aluminum nitride, zinc oxide, single crystal lithium tantalate, lead zirconate titanate and lithium niobate according to any proportion, the thickness is 10nm-4000nm, and the transverse width is 180 mu m-250 mu m.
3. The method for manufacturing a single crystal thin film bulk acoustic resonator with an electrode having a ring groove and a stripe-shaped protrusion according to claim 1, comprising: the material of the first layer to be bonded and the material of the second layer to be bonded are one or two of silicon oxide and silicon in any proportion, and the thickness of the first layer to be bonded and the second layer to be bonded are both 0.1-10 mu m.
4. The method for manufacturing a single crystal thin film bulk acoustic resonator with an electrode having a ring groove and a stripe-shaped protrusion according to claim 1, comprising: the thickness of the lower electrode is 50nm-500nm, and the transverse width is 30-240 μm.
5. The method for manufacturing a single crystal thin film bulk acoustic resonator with an electrode having a ring groove and a stripe-shaped protrusion according to claim 1, comprising: the thickness of the upper electrode is 50nm-500nm, the transverse width is 30-240 μm, and the thickness and the transverse width of the upper electrode are both smaller than those of the lower electrode.
6. The method for manufacturing a single crystal thin film bulk acoustic resonator with an electrode having a ring groove and a stripe-shaped protrusion according to claim 1, comprising: the sacrificial layer is made of one or two of polycrystalline silicon, amorphous silicon, silicon dioxide and doped carbon dioxide according to any proportion; the thickness of the sacrificial layer is 0.5-3 μm, and the lateral width is 20-230 μm.
7. The method for manufacturing a single crystal thin film bulk acoustic resonator with an electrode having a ring groove and a stripe-shaped protrusion according to claim 1, comprising: the depth and the transverse width of the lower ring groove and the upper ring groove are equal, the depth is 20nm-200nm, and the transverse width is more than 0 mu m and less than 10 mu m; the thickness and the transverse width of the lower strip-shaped bulge I, the lower strip-shaped bulge II, the upper strip-shaped bulge I and the upper strip-shaped bulge II are equal, the thickness is 50nm-300nm, and the transverse width is 0.5 mu m-10 mu m.
8. The method for manufacturing a single crystal thin film bulk acoustic resonator having an electrode with a ring groove and a stripe-shaped protrusion according to any one of claims 1 to 7, wherein: the thickness of the substrate is 500 μm; the thickness of the first layer to be bonded and the thickness of the second layer to be bonded are both 5 micrometers; the thickness of the protective layer is 1 μm, and the transverse width is 190 μm; the thickness of the lower electrode is 180nm, and the transverse width of the lower electrode is 170 mu m; the thickness of the piezoelectric layer is 700nm, and the transverse width of the piezoelectric layer is 200 μm; the thickness of the upper electrode is 140nm, and the transverse width is 150 mu m; the transverse width of the cavity is 180 mu m, and the thickness of the cavity is 2 mu m; the depth of the lower ring groove and the depth of the upper ring groove are both 100nm, and the transverse width of the lower ring groove and the transverse width of the upper ring groove are both 3.2 mu m; the thickness of the lower strip-shaped bulge I, the thickness of the lower strip-shaped bulge II, the thickness of the upper strip-shaped bulge I and the thickness of the upper strip-shaped bulge II are all 200nm, and the transverse width of each of the lower strip-shaped bulge I, the lower strip-shaped bulge II, the upper strip-shaped bulge I and the upper strip-shaped bulge II is 2.7 mu m.
9. The method for manufacturing a single crystal thin film bulk acoustic resonator having an electrode with a ring groove and a stripe-shaped protrusion according to claim 8, comprising: the substrate, the first layer to be bonded and the second layer to be bonded are made of silicon, the piezoelectric layer and the protective layer are made of aluminum nitride, and the upper electrode and the lower electrode are made of molybdenum.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110986873.4A CN113839637A (en) | 2021-08-26 | 2021-08-26 | Preparation method of monocrystal film bulk acoustic resonator with electrode ring groove and strip-shaped bulges |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110986873.4A CN113839637A (en) | 2021-08-26 | 2021-08-26 | Preparation method of monocrystal film bulk acoustic resonator with electrode ring groove and strip-shaped bulges |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113839637A true CN113839637A (en) | 2021-12-24 |
Family
ID=78961276
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110986873.4A Pending CN113839637A (en) | 2021-08-26 | 2021-08-26 | Preparation method of monocrystal film bulk acoustic resonator with electrode ring groove and strip-shaped bulges |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113839637A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115225051A (en) * | 2022-09-20 | 2022-10-21 | 深圳新声半导体有限公司 | Resonator structure, method for producing a resonator structure |
| WO2023202548A1 (en) * | 2022-04-20 | 2023-10-26 | 京东方科技集团股份有限公司 | Bulk acoustic wave resonator, method for preparing bulk acoustic wave resonator, and electronic device |
Citations (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110298564A1 (en) * | 2009-02-20 | 2011-12-08 | Kazuki Iwashita | Thin-Film Piezoelectric Resonator and Thin-Film Piezoelectric Filter Using the Same |
| CN102801400A (en) * | 2011-05-24 | 2012-11-28 | 太阳诱电株式会社 | Filter and duplexer |
| US20170054430A1 (en) * | 2015-08-21 | 2017-02-23 | Rf Micro Devices, Inc. | Baw resonator having multi-layer electrode and bo ring close to piezoelectric layer |
| US20180226939A1 (en) * | 2015-08-07 | 2018-08-09 | Piezo Studio Inc. | Method for manufacturing piezoelectric thin-film element |
| WO2019029912A1 (en) * | 2017-08-07 | 2019-02-14 | RF360 Europe GmbH | Baw resonator with reduced spurious modes and increased quality factor |
| CN109981069A (en) * | 2019-03-13 | 2019-07-05 | 电子科技大学 | Thin film bulk acoustic wave resonator preparation method and bulk acoustic wave resonator with separation layer |
| JP2019193168A (en) * | 2018-04-26 | 2019-10-31 | サムソン エレクトロ−メカニックス カンパニーリミテッド． | Bulk acoustic resonator and manufacturing method thereof |
| CN111010138A (en) * | 2019-12-05 | 2020-04-14 | 武汉大学 | High Q bulk acoustic wave resonator |
| CN111010116A (en) * | 2019-08-13 | 2020-04-14 | 天津大学 | Bulk acoustic wave resonator, filter and electronic device with height-graded bump structure |
| CN111245397A (en) * | 2019-12-06 | 2020-06-05 | 天津大学 | Bulk acoustic wave resonator, method of manufacturing bulk acoustic wave resonator, bulk acoustic wave resonator unit, filter, and electronic apparatus |
| CN111327294A (en) * | 2018-12-13 | 2020-06-23 | 天津威盛株式会社 | Piezoelectric thin film resonator |
| CN111384909A (en) * | 2018-12-27 | 2020-07-07 | 天津大学 | Bulk acoustic wave resonator, filter, and electronic device having asymmetric electrode thickness |
| CN111404509A (en) * | 2019-12-27 | 2020-07-10 | 瑞声科技(新加坡)有限公司 | Film bulk acoustic resonator |
| US20200336129A1 (en) * | 2019-04-19 | 2020-10-22 | Akoustis, Inc. | Baw resonators with antisymmetric thick electrodes |
| CN112039466A (en) * | 2020-05-20 | 2020-12-04 | 中芯集成电路（宁波）有限公司上海分公司 | Film bulk acoustic resonator and manufacturing method thereof |
| CN112398460A (en) * | 2020-04-14 | 2021-02-23 | 诺思(天津)微系统有限责任公司 | Multiplexer and communication equipment |
-
2021
- 2021-08-26 CN CN202110986873.4A patent/CN113839637A/en active Pending
Patent Citations (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110298564A1 (en) * | 2009-02-20 | 2011-12-08 | Kazuki Iwashita | Thin-Film Piezoelectric Resonator and Thin-Film Piezoelectric Filter Using the Same |
| CN102801400A (en) * | 2011-05-24 | 2012-11-28 | 太阳诱电株式会社 | Filter and duplexer |
| US20180226939A1 (en) * | 2015-08-07 | 2018-08-09 | Piezo Studio Inc. | Method for manufacturing piezoelectric thin-film element |
| US20170054430A1 (en) * | 2015-08-21 | 2017-02-23 | Rf Micro Devices, Inc. | Baw resonator having multi-layer electrode and bo ring close to piezoelectric layer |
| WO2019029912A1 (en) * | 2017-08-07 | 2019-02-14 | RF360 Europe GmbH | Baw resonator with reduced spurious modes and increased quality factor |
| JP2019193168A (en) * | 2018-04-26 | 2019-10-31 | サムソン エレクトロ−メカニックス カンパニーリミテッド． | Bulk acoustic resonator and manufacturing method thereof |
| CN111327294A (en) * | 2018-12-13 | 2020-06-23 | 天津威盛株式会社 | Piezoelectric thin film resonator |
| CN111384909A (en) * | 2018-12-27 | 2020-07-07 | 天津大学 | Bulk acoustic wave resonator, filter, and electronic device having asymmetric electrode thickness |
| CN109981069A (en) * | 2019-03-13 | 2019-07-05 | 电子科技大学 | Thin film bulk acoustic wave resonator preparation method and bulk acoustic wave resonator with separation layer |
| US20200336129A1 (en) * | 2019-04-19 | 2020-10-22 | Akoustis, Inc. | Baw resonators with antisymmetric thick electrodes |
| CN111010116A (en) * | 2019-08-13 | 2020-04-14 | 天津大学 | Bulk acoustic wave resonator, filter and electronic device with height-graded bump structure |
| CN111010138A (en) * | 2019-12-05 | 2020-04-14 | 武汉大学 | High Q bulk acoustic wave resonator |
| CN111245397A (en) * | 2019-12-06 | 2020-06-05 | 天津大学 | Bulk acoustic wave resonator, method of manufacturing bulk acoustic wave resonator, bulk acoustic wave resonator unit, filter, and electronic apparatus |
| CN111404509A (en) * | 2019-12-27 | 2020-07-10 | 瑞声科技(新加坡)有限公司 | Film bulk acoustic resonator |
| CN112398460A (en) * | 2020-04-14 | 2021-02-23 | 诺思(天津)微系统有限责任公司 | Multiplexer and communication equipment |
| CN112039466A (en) * | 2020-05-20 | 2020-12-04 | 中芯集成电路（宁波）有限公司上海分公司 | Film bulk acoustic resonator and manufacturing method thereof |
Non-Patent Citations (3)
| Title |
|---|
| LI, X.; BAO, J.-F.; HUANG, Y.; ZHANG, B.; TANG, G.; OMORI, T.; H: "《Use of double-raised-border structure for quality factor enhancement of type II piston mode FBAR》", 《IN PROCEEDINGS OF THE 2017 JOINT CONFERENCE OF THE EUROPEAN FREQUENCY AND TIME FORUM AND IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM (EFTF/IFC)》 * |
| NGOC NGUYEN, A. JOHANNESSEN AND U. HANKE: "《Design of high-Q Thin Film Bulk Acoustic resonator using dual-mode reflection》", 《2014 IEEE NTERNATIONAL ULTRASONICS SYMPOSIUM》 * |
| 杜波: "《空腔型体声波滤波器及其宽带化技术研究》", 《知网》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023202548A1 (en) * | 2022-04-20 | 2023-10-26 | 京东方科技集团股份有限公司 | Bulk acoustic wave resonator, method for preparing bulk acoustic wave resonator, and electronic device |
| CN115225051A (en) * | 2022-09-20 | 2022-10-21 | 深圳新声半导体有限公司 | Resonator structure, method for producing a resonator structure |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6924717B2 (en) | Tapered electrode in an acoustic resonator | |
| JP4058001B2 (en) | Structure and fabrication procedure to achieve high Q and low insertion loss FBARs | |
| WO2021109444A1 (en) | Bulk acoustic resonator, fabrication method therefor, filter and electronic device | |
| CN112311347B (en) | Structure capable of improving quality factor Q value of film bulk acoustic resonator | |
| CN113839637A (en) | Preparation method of monocrystal film bulk acoustic resonator with electrode ring groove and strip-shaped bulges | |
| WO2020258334A1 (en) | Resonator and preparation method therefor | |
| WO2007063842A1 (en) | Acoustic resonator and its fabricating method | |
| JP2006503448A5 (en) | ||
| CN113193846B (en) | Film bulk acoustic resonator with hybrid transverse structural features | |
| WO2020177556A1 (en) | Bulk acoustic wave resonator having concave structure and convex structure, filter, and electronic device | |
| EP4087131A1 (en) | Bulk acoustic wave resonator having electrical isolation layer and manufacturing method therefor, filter, and electronic device | |
| CN112134540B (en) | Bulk acoustic wave resonator with composite electrode and preparation method thereof | |
| CN113708740B (en) | Piezoelectric film bulk acoustic resonator and preparation method thereof | |
| WO2022143286A1 (en) | Single-crystal acoustic resonator, filter, and electronic device | |
| CN111817682A (en) | Film bulk acoustic resonator and preparation method thereof | |
| WO2024040679A1 (en) | Bulk acoustic resonator, fabrication method therefor, filter, and electronic device | |
| WO2021189964A1 (en) | Thin film bulk acoustic resonator and manufacturing method therefor | |
| CN212163290U (en) | Scandium-doped aluminum nitride lamb wave resonator | |
| CN114268290A (en) | Preparation method of high-Q-value single crystal film bulk acoustic resonator | |
| CN113839638A (en) | Method for preparing film bulk acoustic resonator with electrodes provided with double-ring and bridge structures | |
| CN113824420A (en) | Preparation method of single crystal film bulk acoustic resonator with electrode with double annular structure | |
| CN114257209A (en) | Double-sided raised film bulk acoustic wave device for restraining multi-mode lamb waves | |
| CN212305272U (en) | Film bulk acoustic resonator | |
| CN112953446B (en) | Preparation method of bulk acoustic wave resonator and bulk acoustic wave resonator | |
| TWI775603B (en) | Acoustic resonator filter |
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 |