CN113452341B - Air gap type bulk acoustic wave resonator based on thermotropic SMP and preparation method thereof - Google Patents
Air gap type bulk acoustic wave resonator based on thermotropic SMP and preparation method thereof Download PDFInfo
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- 238000000034 method Methods 0.000 claims abstract description 48
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- 239000010937 tungsten Substances 0.000 claims description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 9
- 238000000137 annealing Methods 0.000 claims description 9
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- 238000005530 etching Methods 0.000 claims description 7
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- 239000007769 metal material Substances 0.000 claims description 6
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 6
- 238000010382 chemical cross-linking Methods 0.000 claims description 5
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- 238000007334 copolymerization reaction Methods 0.000 claims description 3
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- 229920000431 shape-memory polymer Polymers 0.000 description 32
- 239000010408 film Substances 0.000 description 17
- 229920001721 polyimide Polymers 0.000 description 16
- 239000004642 Polyimide Substances 0.000 description 12
- 229910052751 metal Inorganic materials 0.000 description 12
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- 229920001187 thermosetting polymer Polymers 0.000 description 9
- 238000001755 magnetron sputter deposition Methods 0.000 description 7
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
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- 238000002207 thermal evaporation Methods 0.000 description 6
- 238000000059 patterning Methods 0.000 description 5
- 238000007493 shaping process Methods 0.000 description 5
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
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- 229910021426 porous silicon Inorganic materials 0.000 description 4
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- 229910004298 SiO 2 Inorganic materials 0.000 description 2
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- 238000005459 micromachining Methods 0.000 description 2
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- 235000012239 silicon dioxide Nutrition 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- WUPHOULIZUERAE-UHFFFAOYSA-N 3-(oxolan-2-yl)propanoic acid Chemical compound OC(=O)CCC1CCCO1 WUPHOULIZUERAE-UHFFFAOYSA-N 0.000 description 1
- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 description 1
- 229910052980 cadmium sulfide Inorganic materials 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- DQUIAMCJEJUUJC-UHFFFAOYSA-N dibismuth;dioxido(oxo)silane Chemical compound [Bi+3].[Bi+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O DQUIAMCJEJUUJC-UHFFFAOYSA-N 0.000 description 1
- PSHMSSXLYVAENJ-UHFFFAOYSA-N dilithium;[oxido(oxoboranyloxy)boranyl]oxy-oxoboranyloxyborinate Chemical compound [Li+].[Li+].O=BOB([O-])OB([O-])OB=O PSHMSSXLYVAENJ-UHFFFAOYSA-N 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
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- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 description 1
- 238000001459 lithography Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 239000005360 phosphosilicate glass Substances 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
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- 229910052719 titanium Inorganic materials 0.000 description 1
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- 230000009466 transformation Effects 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
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
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
- H03H2003/023—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks the resonators or networks being of the membrane type
Abstract
The invention discloses an air gap type bulk acoustic wave resonator based on a thermotropic SMP and a preparation method thereof, belonging to the technical field of basic electronic circuits. The air gap type acoustic wave resonator comprises an upper electrode, a piezoelectric layer, a lower electrode, a polymer film, an air cavity and a polymer substrate, wherein the polymer film and the air cavity are formed by ion implantation and high-temperature internal stress. The cavity structure is directly formed by utilizing the difference of the thermal expansion coefficients of the piezoelectric film and the thermal SMP through ion implantation and temperature change. The method does not need to arrange a sacrificial material, can effectively solve the problem that the sacrificial layer is difficult to remove in the traditional air gap structure, and can prepare devices with higher yield in shorter time.
Description
Technical Field
The invention relates to the technology of radio frequency micro-electromechanical systems, in particular to an air gap type bulk acoustic wave resonator based on thermotropic SMP (Shape Memory Polymer ) and a preparation method thereof, belonging to the technical field of basic electronic circuits.
Background
Currently, filters are widely used in wireless communications, and annual demand is estimated to be hundreds of billions. The filters mainly include four types of capacitive reactance filters, dielectric filters, surface acoustic wave filters, and thin film bulk acoustic wave filters (FBARs, film Bulk Acoustic Resonator). Among them, the thin film bulk acoustic filter has the characteristics of small size, high application frequency, low insertion loss, etc., and is becoming a mainstream solution for a filter chip of a wireless communication system. The film bulk acoustic wave filter converts electric energy (signal) into acoustic waves by using the inverse piezoelectric effect of a piezoelectric film to form resonance, and three main types of film bulk acoustic wave resonator structures are currently in main flow: back etching type, solid state assembly type, and air gap type.
The back etching type bulk acoustic wave resonator is based on MEMS bulk silicon micromachining technology, and the back of a Si sheet is etched to form an air metal interface on the lower surface of a piezoelectric vibrating pile, so that acoustic waves are limited in the piezoelectric vibrating pile. However, this structure requires large area removal of the Si substrate during the manufacturing process, which tends to result in reduced mechanical robustness of the resonator, and reduced yield, and thus it is difficult to meet the demands of industrial production.
The solid-state assembly type bulk acoustic wave resonator adopts Bragg reflection layers formed by high and low acoustic impedance materials alternately to limit acoustic waves in the piezoelectric oscillation stack. However, the number of layers of the resistive material must be sufficiently large and the thickness must be precisely controlled to ensure that the performance of the resonator meets the requirements, which means that the preparation process is complex and complicated, and the process cost is high. In addition, the effect of the bragg reflection layer is always not as high as air, and thus the Q value of the solid state assembly resonator is not high enough.
The air gap type bulk acoustic wave resonator is based on the MEMS surface micromachining technology, an air gap is formed on the upper surface of a silicon wafer by a method of filling sacrificial materials first and removing the sacrificial materials finally so as to limit acoustic waves in a piezoelectric oscillation stack, a large amount of substrates are not required to be removed, and a complicated process is not required to form an acoustic reflection layer stacked layer by layer, so that the defects of reduced mechanical firmness of the back etching type bulk acoustic wave resonator and complex manufacturing process of the solid assembly type bulk acoustic wave resonator can be overcome, and the key point of the manufacturing of the structure is the removal of the sacrificial layers. The traditional sacrificial layer is made of phosphosilicate glass and the like, after the sacrificial layer material is filled in the substrate, corrosion holes are preset, the sacrificial layer is removed by means of soaking with corrosive liquid such as hydrofluoric acid and the like, the defects that the sacrificial layer is difficult to remove and the release time is long exist, the subsequent deposited piezoelectric layer is poor in crystallization performance and multiple in defects, the structural layer is easily damaged by the corrosive liquid, and the performance of the resonator is affected.
The invention patent with the application number of 20201102064. X discloses a self-supporting air gap acoustic wave resonator based on porous silicon and a preparation method thereof, wherein a self-supporting silicon material layer and a cavity are formed by high-temperature migration of the porous silicon, and the porous silicon is enabled to be high Wen Qianyi to form a silicon film and a cavity structure by high-temperature annealing, so that the inherent defects of the traditional air gap bulk acoustic wave resonator are overcome. However, too low annealing temperature or insufficient annealing time can lead to incomplete migration of porous silicon, uneven boundaries of a silicon supporting layer and a cavity, more clutter on an admittance curve of the obtained bulk acoustic wave resonator, and reduced quality factor Q value, which requires strict control of annealing temperature and time in the preparation process, and low yield.
In summary, the present invention aims to provide a new technical solution for solving the inherent defects of the conventional air gap bulk acoustic wave resonator by utilizing the characteristic that the thermal expansion coefficients of the thermotropic SMP and the piezoelectric film material are inconsistent.
Disclosure of Invention
The invention aims to overcome the defects of the background art, provide an air gap type bulk acoustic wave resonator based on a thermotropic SMP and a preparation method thereof, and solve the technical problem that the bulk acoustic wave resonator with the air gap formed after the sacrificial layer is filled firstly influences the performance of the resonator by utilizing the characteristic that the thermal expansion coefficients of a piezoelectric film and the thermotropic SMP are inconsistent to realize the direct formation of an air gap on the thermotropic SMP substrate.
The invention adopts the following technical scheme for realizing the purposes of the invention:
the air gap type bulk acoustic wave resonator based on the thermotropic SMP sequentially comprises an upper electrode, a piezoelectric layer, a lower electrode, a polymer film, an air cavity and a polymer substrate from top to bottom, wherein the polymer film is covered on the air cavity and is formed by heating and breaking after partial ion implantation of the polymer substrate.
Further, in order to prevent collapse of the three-layer electrode structure, the upper electrode and the lower electrode are composite electrodes formed by depositing heavy metal materials in the middle of common electrode materials.
Further, in order to prevent the three-layer electrode structure from falling off and breaking in the high-temperature annealing process, a support layer is firstly prepared on the thermotropic SMP substrate, and then the three-layer electrode structure is prepared on the support layer, wherein the support layer is made of one or more of silicon dioxide and silicon carbide.
Further, the thickness of the upper electrode and the bottom electrode is 10 nm-900 nm, and the thickness of the piezoelectric layer is 100 nm-3 μm.
Further, the electrode material is one or a combination of a plurality of platinum, gold, silver, molybdenum, aluminum, titanium, platinum, tungsten, copper and chromium.
Further, the piezoelectric layer material is one or a combination of more of lithium niobate, aluminum nitride, zinc oxide, lithium zirconate, lithium tantalate, lithium tetraborate, bismuth germanate, bismuth silicate, cadmium sulfide and quartz.
Further, the thickness of the polymer film is 100nm to 5 μm, and the depth of the air cavity is 1 μm to 30 μm.
Further, ion implantation is performed at the position where the air cavity is formed in the thermally induced SMP substrate, after 20-50 μm is reserved at the two ends of the thermally induced SMP during the implantation, partial helium ion implantation is performed in the middle.
The invention designs a preparation method of an air gap bulk acoustic wave resonator based on a thermotropic SMP, which mainly comprises the following steps:
1. performing local ion implantation on the thermotropic SMP substrate, wherein the preparation method of the thermotropic SMP comprises a copolymerization method, a high-energy radiation crosslinking method and a chemical crosslinking method;
2. sequentially depositing a lower electrode, a piezoelectric layer and an upper electrode on a thermotropic SMP substrate;
3. the device is heated up and heat treated in the hydrogen or inert gas environment, the first step is to heat up to 100 ℃ to 200 ℃ and keep for a period of time to maximize bonding strength, the second step is to change the temperature of the wafer group in a relatively short time, the changing speed is about 10 ℃/min, thereby causing larger internal stress to cause fracture of a damaged layer and the film is automatically broken to form a cavity and a thin layer polymer on the cavity by the internal stress.
Further, for the air gap bulk acoustic wave resonator adopting the composite electrode as the upper electrode and the lower electrode, in the process of depositing the upper electrode and the lower electrode, a common electrode material layer is deposited, the common electrode material layer is subjected to patterning treatment to form a cavity, and a heavy metal material is deposited in the cavity.
The invention also provides a preparation method of the second air gap bulk acoustic wave resonator based on the thermotropic SMP, which utilizes the inconsistent thermal expansion coefficients of the supporting layer and the thermotropic SMP substrate to form an air cavity firstly and then deposit a sandwich structure, and mainly comprises the following steps:
1. performing local ion implantation on a thermotropic SMP substrate, wherein the preparation method of the thermotropic SMP comprises a copolymerization method, a high-energy radiation crosslinking method and a chemical crosslinking method;
2. depositing a support layer on a thermally induced SMP substrate;
3. heating the device in a hydrogen or inert gas environment, wherein the first step is to heat to 100-200 ℃ for a period of time to maximize bonding strength, and the second step is to change the temperature of the wafer set within a relatively short period of time at a rate of about 10 ℃/min, so that larger internal stress is caused, the damage layer is broken, and the film is automatically broken to form a cavity by the internal stress;
4. and sequentially depositing a lower electrode, a piezoelectric layer and an upper electrode on the supporting layer to form the air gap bulk acoustic wave resonator.
The invention adopts the technical scheme and has the following beneficial effects: the preparation method of the air gap bulk acoustic wave resonator of the thermotropic SMP provided by the invention does not need to remove a large number of substrates, does not need to repeatedly stack acoustic reflection materials, simultaneously avoids structural damage caused by corrosion holes and time consumption caused by corrosion of a sacrificial layer, and has the advantages of good mechanical firmness, excellent performance, simple preparation process and low manufacturing cost, can be compatible with the conventional CMOS circuit process, and has ideal industrial mass production application prospect.
Drawings
Fig. 1 (a) to 1 (e) are flowcharts of an air gap bulk acoustic wave resonator based on a thermotropic SMP according to embodiment 1 of the present invention.
Fig. 2 (a) to 2 (g) are flowcharts of an air gap bulk acoustic wave resonator based on a thermotropic SMP according to embodiment 2 of the present invention.
Fig. 3 (a) to 3 (f) are flowcharts of an air gap bulk acoustic wave resonator based on a thermotropic SMP according to embodiment 3 of the present invention.
The reference numerals in the figures illustrate: 1. an Al upper electrode, 2, an AlN piezoelectric layer, 3, an Al lower electrode, 4, a polyimide film, 5, an air cavity, 6, a polymer substrate, 7, metallic tungsten, 8, metallic aluminum, 9, goldIs tungsten, 10, metal aluminum, 11, siO 2 And a support layer.
Detailed Description
The technical scheme of the invention is described in detail below with reference to the accompanying drawings.
The air gap bulk acoustic wave resonator based on the thermotropic SMP, disclosed by the invention, takes an air cavity formed in a thermotropic SMP substrate as an acoustic reflection layer, and the preparation method of the air cavity is obviously different from that of the traditional air gap bulk acoustic wave resonator. The principle of the invention for preparing the air cavity is as follows: the local lattice damage layer is formed by an ion implantation method, so that the local lattice structure is destroyed, the corresponding chemical bonds are weakened, the lattice strength is reduced, and then the air cavity structure is directly formed by utilizing the characteristic that the thermal expansion coefficients of the piezoelectric film and the thermotropic SMP are inconsistent through temperature change. The structure of the air gap type bulk acoustic wave resonator based on the thermotropic SMP of the present invention and its preparation method are specifically described below by taking three examples.
Embodiment one:
the preparation method of the air gap bulk acoustic wave resonator based on the thermotropic SMP in the embodiment comprises the steps of preparing thermosetting polyimide serving as a polymer substrate through a chemical crosslinking method, carrying out local ion implantation on the thermosetting polyimide, sequentially depositing a metal Al lower electrode, an AlN piezoelectric layer and an Al upper electrode on the substrate, and finally breaking a polymer film through internal stress caused by temperature change to form an air cavity and shaping the air cavity at high temperature to form the air gap bulk acoustic wave resonator based on the thermosetting polyimide. The method comprises the following specific steps:
1. the polymer substrate 6 is prepared by polyimide with low crosslinking density, helium ion implantation is carried out at the position of the polymer substrate 6 forming the air cavity 5, and the implantation dosage is 2 multiplied by 10 16 ions/cm 2 As shown in fig. 1 (a);
2. a 200nm metal aluminum bottom electrode 3 is deposited on a polymer substrate 6 by adopting a thermal evaporation method, a magnetron sputtering method and the like, as shown in fig. 1 (b);
3. sputtering a layer of AlN piezoelectric layer 2 with C-axis orientation of 2 μm on the lower electrode 3, using nitrogen and argon flows as process gases, growing SiO by PECVD 2 Patterning AlN film as mask as shown in figure 1c) Shown;
4. depositing an Al upper electrode 1 with a thickness of 200nm by adopting a thermal evaporation method, a magnetron sputtering method and the like, as shown in a figure 1 (d);
5. at H 2 Heating to 170 ℃ in the environment, staying for 5 hours to ensure that the wafer adhesiveness is optimal, then heating to 260 ℃ in 15 minutes, and breaking the polyimide film 4 above the helium particle injection part by internal stress caused by temperature change to form a polymer elastic film layer with the depth of 2 mu m of air cavity 5 and 400nm above the air cavity, cooling to 170 ℃ and shaping to form the air gap bulk acoustic wave resonator based on thermosetting polyimide, as shown in fig. 1 (e).
Embodiment two:
an embodiment illustrates a preparation flow of the air gap acoustic wave resonator according to the present invention, and considering that the polymer film above the air cavity is in a state of thin in the middle and thick on both sides in the process of forming the air cavity, the embodiment considers that a composite upper electrode layer and a composite lower electrode layer mixed by heavy metal and common metal are used to prevent collapse of the "sandwich" structure of the resonator. Heavy metal materials include, but are not limited to, W, pt, pb, etc.; common electrode materials include, but are not limited to, al, cu, and the like.
The preparation method of the air gap bulk acoustic wave resonator based on the thermotropic SMP in the embodiment comprises the steps of preparing thermosetting polyimide serving as a polymer substrate through a chemical crosslinking method, carrying out local ion implantation on the thermosetting polyimide, preparing a composite lower electrode on the substrate through deposition and etching processes from outside to inside, sequentially depositing an AlN piezoelectric layer and a composite upper electrode, and finally breaking a polymer film through internal stress caused by temperature change to form an air cavity and shaping at high temperature to form the air gap bulk acoustic wave resonator based on the thermosetting polyimide. The method comprises the following specific steps:
1. the polymer substrate 6 is prepared by polyimide with low crosslinking density, helium ion implantation is carried out at the position of the polymer substrate 6 forming the air cavity 5, and the implantation dosage is 2 multiplied by 10 16 ions/cm 2 As shown in fig. 2 (a);
2. depositing 200nm of metal tungsten 7 on the polymer substrate 6 by adopting a thermal evaporation method, a magnetron sputtering method or the like and flattening the metal tungsten, as shown in fig. 2 (b);
3. patterning the metal tungsten 7 by wet lithography or dry ion etching, and only retaining the peripheral part to form a tungsten etching cavity, as shown in fig. 2 (c);
4. depositing 200nm metal aluminum 8 in the tungsten etching cavity by adopting a thermal evaporation or magnetron sputtering method and the like and flattening to form a composite lower electrode, as shown in fig. 2 (d);
5. sputtering a layer of AlN piezoelectric layer 2 with C-axis orientation of 2 mu m on the composite lower electrode, using nitrogen and argon flows as process gases, and growing SiO by PECVD 2 Patterning the AlN film by using a mask as shown in FIG. 2 (e);
6. preparing a composite upper electrode of metal tungsten 9 and metal aluminum 10 by adopting the methods of the steps 2, 3 and 4, as shown in fig. 2 (f);
7. at H 2 The temperature is raised to about 170 ℃ in the environment and stays for 5 hours, so that the wafer adhesiveness is optimal, the composite electrode is not easy to collapse, rapid temperature rise deformation and thinner polymer film layer formation can be carried out, then the temperature is raised to 260 ℃ in 8 minutes, the internal stress caused by the temperature change breaks the polyimide film to form a polymer elastic film layer with the depth of 3 mu m of air cavity 5 and 200nm above the air cavity 5, and the temperature is reduced to about 170 ℃ for shaping, so that the air gap bulk acoustic wave resonator based on thermosetting polyimide is formed, as shown in fig. 2 (g).
Embodiment III:
the second embodiment illustrates the preparation flow of the air gap acoustic wave resonator with the 'sandwich' electrode structure, which is not easy to collapse, and considers the conditions that the 'sandwich' structure above the polymer substrate is easy to fall off and break in the deformation process in the process of forming the air cavity, so that a supporting layer is added, a cavity is formed first, and then the 'sandwich' structure is prepared, so that the device yield is improved.
The preparation method of the air gap bulk acoustic wave resonator based on the thermotropic SMP in the embodiment is to use thermosetting polyimide and SiO 2 The thermal expansion coefficients of the supporting layers are inconsistent, and the air cavity and the high-temperature annealing are prepared through ion implantationAnd a flexible supporting layer structure on the substrate, wherein a metal Al lower electrode, an AlN piezoelectric layer and an Al upper electrode are sequentially deposited on a film layer of the supporting layer structure, and the specific steps are as follows:
1. the polymer substrate 6 is prepared by polyimide with low crosslinking density, helium ion implantation is carried out at the position of the polymer substrate 6 forming the air cavity 5, and the implantation dosage can be 2 multiplied by 10 16 ions/cm 2 As shown in fig. 3 (a); 2. deposition of 2 μm SiO on the polymer substrate 6 by magnetron sputtering or the like 2 A support layer 11 as shown in fig. 3 (b);
3. at H 2 In the second embodiment, the temperature is raised to about 200 ℃ and stays for 5 hours, so that the wafer adhesiveness is optimal, then the temperature is raised to 320 ℃ within 10 minutes, the polyimide film is broken by the internal stress caused by the temperature change to form an air cavity 5, the temperature is reduced to about 200 ℃ for shaping, and a polymer elastic film layer with the depth of 2 mu m and 400nm above the air cavity 5 is formed;
4. in SiO 2 A 200nm Al lower electrode 3 is deposited on the supporting layer 11 by adopting a thermal evaporation method, a magnetron sputtering method and the like, as shown in fig. 3 (d);
5. sputtering an AlN piezoelectric layer 2 with a C-axis orientation of 2 μm on an Al lower electrode 3, using nitrogen and argon flows as process gases, growing SiO by PECVD 2 Patterning the AlN film by using a mask as shown in FIG. 3 (e);
6. a200 nm Al upper electrode 1 is deposited by a thermal evaporation or magnetron sputtering method, etc., to form a bulk acoustic wave vibrator based on a thermotropic SMP, as shown in FIG. 3 (f).
In summary, the above three embodiments merely illustrate three preferred embodiments of the present invention, and the embodiments of the present invention are not limited to the above embodiments, and other technical solutions that are equivalent to the above embodiments and are consistent with the concept of the present invention and obtained by those skilled in the art from equivalent transformation of the above embodiments fall within the scope of protection defined by the claims of the present invention.
Claims (10)
1. An air gap bulk acoustic wave resonator based on a thermotropic SMP, comprising: the device comprises a thermally induced SMP substrate, an air gap, a lower electrode, a piezoelectric layer and an upper electrode, wherein the air gap is formed in the thermally induced SMP substrate through a helium ion implantation process and a high-temperature annealing process, the lower electrode, the piezoelectric layer and the upper electrode are sequentially deposited on the thermally induced SMP substrate, the high-temperature annealing process comprises two high-temperature treatments and an annealing treatment, the two high-temperature treatments comprise heating treatment and then heating treatment, the heating treatment is performed firstly to enable the device to be in an optimal state of adhesiveness, and then the heating treatment is performed to enable a polymer film above an injection position of the particles to be broken to form an air cavity and a polymer film covering the top of the air cavity.
2. The air gap type bulk acoustic wave resonator based on thermotropic SMP of claim 1, wherein the lower electrode and the upper electrode are composite electrodes formed by etching a common electrode material deposition layer followed by depositing a heavy metal material in a cavity of the common electrode material deposition layer.
3. The air gap bulk acoustic resonator based on a thermotropic SMP of claim 1, wherein a silica support layer is deposited on the thermotropic SMP polymer, and wherein a lower electrode, a piezoelectric layer, and an upper electrode are sequentially deposited on the silica support layer.
4. The thermally induced SMP-based air-gap bulk acoustic resonator of claim 2 wherein the common electrode material is one or a combination of more of aluminum and copper.
5. The thermally induced SMP-based air-gap bulk acoustic resonator of claim 2, wherein the heavy metal material is a combination of one or more of tungsten, platinum, and lead.
6. The method for manufacturing the thermotropic SMP-based air gap bulk acoustic wave resonator of claim 1, comprising the steps of:
A. preparing a thermotropic SMP substrate, and implanting helium ions into the part of the thermotropic SMP substrate forming an air cavity;
B. depositing a lower electrode on the thermotropic SMP substrate, sputtering a piezoelectric layer on the lower electrode, and depositing an upper electrode on the piezoelectric layer;
C. and heating the device structure formed after the upper electrode is deposited to an optimal state of adhesiveness, heating until the polymer film breaks to form an air cavity and a polymer film covered on the top of the air cavity, and cooling until the device is shaped.
7. The method for preparing an air gap bulk acoustic wave resonator based on a thermotropic SMP of claim 6, wherein when the lower electrode and the upper electrode are composite electrodes, the method for depositing the lower electrode or the upper electrode in step B is as follows: and depositing a common electrode material layer, performing graphical treatment on the common electrode material layer to form a cavity, and depositing a heavy metal material in the cavity.
8. The method of claim 6, wherein the step a is followed by the step a of depositing a silica support layer on the thermally-induced SMP substrate, the step C is followed by the step B of forming an air cavity, and the step B is followed by the step B of forming a three-layer electrode structure.
9. The method for preparing a thermotropic SMP-based air-gap bulk acoustic resonator according to claim 6, wherein the method for preparing the thermotropic SMP substrate in step a is a copolymerization method or a high-energy radiation crosslinking method or a chemical crosslinking method.
10. The method of fabricating a thermally induced SMP-based air-gap bulk acoustic wave resonator according to claim 6, wherein the heating treatment in step C is performed in a hydrogen or inert gas atmosphere at a temperature higher than 150 ℃.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5759904A (en) * | 1996-11-06 | 1998-06-02 | Southwest Research Institute | Suppression of transient enhanced diffusion in ion implanted silicon |
| US5840590A (en) * | 1993-12-01 | 1998-11-24 | Sandia Corporation | Impurity gettering in silicon using cavities formed by helium implantation and annealing |
| CN103780219A (en) * | 2012-10-25 | 2014-05-07 | 安华高科技通用Ip(新加坡)公司 | Accoustic resonator having composite electrodes with integrated lateral features |
| DE102014101805A1 (en) * | 2013-02-14 | 2014-08-28 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Bulk acoustic wave resonator device e.g. thin film bulk acoustic resonator device, for ladder filter for e.g. laptops, has compensation layer including positive temperature coefficient for offsetting portion of negative coefficient |
| CN112073025A (en) * | 2020-09-23 | 2020-12-11 | 浙江大学 | Self-supporting air gap type bulk acoustic wave resonator based on porous silicon and preparation method thereof |
-
2021
- 2021-06-28 CN CN202110719065.1A patent/CN113452341B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5840590A (en) * | 1993-12-01 | 1998-11-24 | Sandia Corporation | Impurity gettering in silicon using cavities formed by helium implantation and annealing |
| US5759904A (en) * | 1996-11-06 | 1998-06-02 | Southwest Research Institute | Suppression of transient enhanced diffusion in ion implanted silicon |
| CN103780219A (en) * | 2012-10-25 | 2014-05-07 | 安华高科技通用Ip(新加坡)公司 | Accoustic resonator having composite electrodes with integrated lateral features |
| DE102014101805A1 (en) * | 2013-02-14 | 2014-08-28 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Bulk acoustic wave resonator device e.g. thin film bulk acoustic resonator device, for ladder filter for e.g. laptops, has compensation layer including positive temperature coefficient for offsetting portion of negative coefficient |
| CN112073025A (en) * | 2020-09-23 | 2020-12-11 | 浙江大学 | Self-supporting air gap type bulk acoustic wave resonator based on porous silicon and preparation method thereof |
Non-Patent Citations (2)
| Title |
|---|
| "Shape-memory polymers as flexible resonator substrates for continuously tunable organic DFB lasers;Senta Schauer;Optical Society of America;第1-9页 * |
| HELIUM-INDUCED POROUS LAYER FORMATION IN SILICON.Mat. Res. Soc. Symp. Proc.1987,第1-6页. * |
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