CN116545402A - Film bulk acoustic resonator and preparation method thereof - Google Patents
Film bulk acoustic resonator and preparation method thereof Download PDFInfo
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- CN116545402A CN116545402A CN202310824876.7A CN202310824876A CN116545402A CN 116545402 A CN116545402 A CN 116545402A CN 202310824876 A CN202310824876 A CN 202310824876A CN 116545402 A CN116545402 A CN 116545402A
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- 238000002360 preparation method Methods 0.000 title abstract description 7
- 239000000758 substrate Substances 0.000 claims abstract description 62
- 239000010409 thin film Substances 0.000 claims abstract description 38
- 230000008093 supporting effect Effects 0.000 claims abstract description 24
- 230000008859 change Effects 0.000 claims abstract description 14
- 238000000034 method Methods 0.000 claims description 33
- 239000000463 material Substances 0.000 claims description 28
- 238000004519 manufacturing process Methods 0.000 claims description 25
- 238000004140 cleaning Methods 0.000 claims description 15
- 238000001755 magnetron sputter deposition Methods 0.000 claims description 14
- 238000005530 etching Methods 0.000 claims description 13
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 12
- 239000011259 mixed solution Substances 0.000 claims description 12
- 230000008569 process Effects 0.000 claims description 12
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 9
- 238000001035 drying Methods 0.000 claims description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 9
- 238000001312 dry etching Methods 0.000 claims description 8
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 6
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 6
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 6
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 6
- 229910052782 aluminium Inorganic materials 0.000 claims description 6
- 239000013078 crystal Substances 0.000 claims description 6
- 229910000040 hydrogen fluoride Inorganic materials 0.000 claims description 6
- 238000002156 mixing Methods 0.000 claims description 6
- 229920002120 photoresistant polymer Polymers 0.000 claims description 6
- 238000004544 sputter deposition Methods 0.000 claims description 6
- 229910052721 tungsten Inorganic materials 0.000 claims description 6
- 238000005406 washing Methods 0.000 claims description 6
- 239000011248 coating agent Substances 0.000 claims description 5
- 238000000576 coating method Methods 0.000 claims description 5
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- 229910052751 metal Inorganic materials 0.000 claims description 4
- 239000002184 metal Substances 0.000 claims description 4
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- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 3
- 239000002318 adhesion promoter Substances 0.000 claims description 3
- 229910052454 barium strontium titanate Inorganic materials 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
- 229910052451 lead zirconate titanate Inorganic materials 0.000 claims description 3
- 229910052594 sapphire Inorganic materials 0.000 claims description 3
- 239000010980 sapphire Substances 0.000 claims description 3
- 229910052710 silicon Inorganic materials 0.000 claims description 3
- 239000010703 silicon Substances 0.000 claims description 3
- 150000003377 silicon compounds Chemical class 0.000 claims description 3
- 238000002791 soaking Methods 0.000 claims description 3
- 239000011787 zinc oxide Substances 0.000 claims description 3
- -1 liGaO2 Substances 0.000 claims description 2
- 239000010408 film Substances 0.000 abstract description 12
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 6
- 238000009616 inductively coupled plasma Methods 0.000 description 4
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 3
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- 238000009826 distribution Methods 0.000 description 3
- 229910052750 molybdenum Inorganic materials 0.000 description 3
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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
- H03H9/02—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
-
- 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
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
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 provides a film bulk acoustic resonator and a preparation method thereof, and relates to the technical field of semiconductor devices. The thin film bulk acoustic resonator comprises a substrate, a supporting layer, a bottom electrode layer, a piezoelectric layer and a top electrode layer, wherein a first groove is formed in the top of the substrate; the supporting layer is the upper layer of the substrate and forms a cavity with the first groove; the bottom electrode layer is the upper layer of the supporting layer; the piezoelectric layer is the upper layer of the bottom electrode layer; the top electrode layer is the upper layer of the piezoelectric layer; the upper surface of top electrode layer digs and is equipped with round second recess, and the second recess is cut apart the upper surface of top electrode layer into load portion and gradient gradual change portion, and load portion is located the profile edge of top electrode layer and surrounds gradient gradual change portion. The film bulk acoustic resonator can effectively inhibit TE vibration modes and restrict RL vibration modes in the electrode by reasonably designing the edge of the electrode, thereby achieving the effects of weakening parasitic resonance and avoiding energy leakage.
Description
Technical Field
The invention relates to the technical field of semiconductor devices, in particular to a film bulk acoustic resonator and a preparation method thereof.
Background
The film bulk acoustic resonator is mainly composed of three parts: the piezoelectric resonator comprises a substrate, an acoustic wave reflecting layer and a sandwich piezoelectric oscillation stack formed by upper and lower electrodes and a piezoelectric film sandwiched between the upper and lower electrodes. When the FBAR device works, alternating radio frequency voltage applied to the electrodes of the FBAR device can form alternating electric fields at two ends of the electrodes, polarization phenomenon is induced by the existence of inverse piezoelectric effect, so that mechanical vibration and electrical signals periodically change in a composite film formed by the electrodes and the piezoelectric layer, and the standing wave oscillation is generated by longitudinal transmission of the bulk acoustic wave along the piezoelectric body.
In practical use, the resonator mainly has the following two design difficulties:
1. the resonator has a plurality of vibration modes and is characterized by a frequency response curve, namely, a plurality of secondary resonance peaks are accompanied by a main frequency resonance point. The filter comprises TE vibration modes (transverse parasitic modes), wherein the TE vibration modes generate parasitic resonance, and if the parasitic resonance is not restrained, severe fluctuation is formed in the passband of the filter, so that the passband characteristics of the filter are seriously deteriorated;
2. due to the existence of the RL vibration mode (namely Rayleigh-Lamb, including Rayleigh waves and Lamb waves), part of the acoustic energy can be transmitted from the electrode to the periphery, and after reaching the two-dimensional end of the electrode, part of the acoustic energy is inevitably leaked to the substrate.
In view of the above problems, no effective technical solution is currently available.
Disclosure of Invention
The invention aims to provide a film bulk acoustic resonator and a preparation method thereof, which can effectively inhibit TE vibration modes and restrict RL vibration modes in the electrode by reasonably designing the edge of the electrode, thereby achieving the effects of weakening parasitic resonance and avoiding energy leakage.
In a first aspect, the present invention provides a thin film bulk acoustic resonator comprising:
the substrate is provided with a first groove at the top;
the supporting layer is an upper layer of the substrate and forms a cavity with the first groove;
the bottom electrode layer is an upper layer of the supporting layer;
the piezoelectric layer is an upper layer of the bottom electrode layer;
a top electrode layer which is an upper layer of the piezoelectric layer; the upper surface of top electrode layer digs and is equipped with round second recess, the second recess will the upper surface of top electrode layer is cut apart into load portion and gradient gradual change portion, load portion is located the contour edge of top electrode layer and encirclement gradient gradual change portion.
According to the film bulk acoustic resonator provided by the invention, the second groove is formed in the upper surface of the top electrode layer, so that the load part and the gradient gradual change part are segmented, parasitic resonance can be restrained to the greatest extent by the second groove region between the load part and the gradient gradual change part, and meanwhile, the RL vibration mode can be restrained in the electrode, so that the effects of avoiding energy leakage and improving the Q value of the device are achieved.
Further, the depth of the first groove is smaller than 30um.
Further, the cross section of the second groove in the width direction is inverted triangle.
Further, the manufacturing material of the substrate is any one material of silicon, silicon compound, sapphire, liGaO2 and metal.
Further, the bottom electrode layer is made of any one material or any combination of a plurality of materials in Al, mo, W, pt, ti, au.
Further, the top electrode layer is made of any one material or any combination of a plurality of materials in Al, mo, W, pt, ti, au.
Further, the piezoelectric layer is made of single-crystal aluminum nitride, polycrystalline aluminum nitride, zinc oxide, lead zirconate titanate, BST and LiNbO 3 Any one of the following.
In a second aspect, the present invention provides a method for preparing the thin film bulk acoustic resonator, which includes the following steps:
s1, obtaining a cleaned substrate;
s2, etching the first groove on the cleaned substrate based on a dry etching process;
s3, filling a sacrificial layer material in the first groove to obtain a sacrificial layer, wherein the top surface of the sacrificial layer is flush with the top surface of the substrate;
s4, manufacturing the supporting layer on the top surface of the sacrificial layer based on a PECVD method; the supporting layer covers the top surface of the substrate;
s5, manufacturing the bottom electrode layer on the top surface of the supporting layer based on a magnetron sputtering method;
s6, manufacturing the piezoelectric layer on the top surface of the bottom electrode layer based on a magnetron sputtering method;
s7, manufacturing the top electrode layer on the top surface of the piezoelectric layer based on a magnetron sputtering method;
s8, etching the second groove on the top surface of the top electrode layer based on a dry etching process to manufacture the load part and the gradient gradual change part.
Further, the specific steps in step S1 include:
s11, obtaining a substrate to be cleaned;
s12, washing the substrate to be cleaned with acetone and absolute ethyl alcohol in sequence;
s13, using the first mixed solution and the second mixed solution to clean the substrate after washing for the first time; the first mixed solution is prepared by mixing sulfuric acid, hydrogen peroxide and water in a ratio of 3:1:1; the second mixed solution is prepared by mixing hydrogen fluoride and water in a ratio of 1:10;
s14, performing second cleaning on the substrate subjected to the first cleaning by using ionized water;
s15, drying the substrate subjected to the second cleaning for the first time;
s16, cleaning the substrate after the first drying for the third time by using a hydrogen fluoride solution with the concentration of 1.5%;
s17, drying the substrate subjected to the third cleaning for the second time to obtain the cleaned substrate.
Further, the specific steps in step S7 include:
s71, sequentially coating adhesion promoters and photoresist on the top surface of the piezoelectric layer;
s72, exposing the coated piezoelectric layer by using ultraviolet light;
s73, performing sputter deposition on the top surface of the exposed piezoelectric layer based on a magnetron sputtering method so as to manufacture the top electrode layer on the top surface of the piezoelectric layer;
s74, soaking the sputtered and deposited piezoelectric layer and the top electrode layer in acetone to strip the unexposed photoresist.
As can be seen from the above, in the thin film bulk acoustic resonator provided by the invention, the second groove is formed on the top electrode layer, so that the electrode boundary forms a layer of raised frame with high acoustic impedance, on one hand, the acoustic impedance mismatch of the central region and the outside of the resonance region of the resonator can be relieved by the second groove region, so that the energy of TE mode can be more conveniently released from the boundary of the resonator, thereby achieving the purpose of weakening parasitic resonance, and meanwhile, the reflection efficiency of acoustic wave is increased due to the increase of acoustic impedance difference at the material boundary; on the other hand, the RL vibration mode can be restrained in the electrode, so that the effects of avoiding energy leakage, reducing energy loss and improving the Q value (quality factor) of the device are achieved.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the embodiments of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and drawings.
Drawings
Fig. 1 is a schematic structural diagram of a thin film bulk acoustic resonator according to an embodiment of the present invention.
Fig. 2 is a step-by-step fabrication diagram of a thin film bulk acoustic resonator according to an embodiment of the present invention.
Fig. 3 is a schematic structural diagram of a thin film bulk acoustic resonator according to a first comparative example of the present invention.
Fig. 4 is a schematic structural diagram of a thin film bulk acoustic resonator according to a second comparative example of the present invention.
Fig. 5 is a smith chart of a thin film bulk acoustic resonator according to an embodiment of the present invention.
Fig. 6 is a smith chart of a thin film bulk acoustic resonator according to a first comparative example of the present invention.
Fig. 7 is a smith chart of a thin film bulk acoustic resonator according to a second comparative example of the present invention.
Fig. 8 is a graph showing comparison of impedance curves of the thin film bulk acoustic resonators according to the embodiment of the present invention, the first comparative example and the second comparative example, respectively.
Fig. 9 is a Q-value frequency distribution diagram of a thin film bulk acoustic resonator according to an embodiment of the present invention.
Fig. 10 is a Q-value frequency distribution diagram of a thin film bulk acoustic resonator according to a first comparative example of the present invention.
Fig. 11 is a Q-value frequency distribution diagram of a thin film bulk acoustic resonator according to a second comparative example of the present invention.
Fig. 12 is a flowchart of a preparation method according to an embodiment of the present invention.
Description of the reference numerals:
100. a substrate; 110. a cavity; 200. a support layer; 300. a bottom electrode layer; 400. a piezoelectric layer; 500. a top electrode layer; 510. a second groove; 520. a load section; 530. gradient gradual change portion.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present invention and are not to be construed as limiting the present invention.
In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically connected, electrically connected or can be communicated with each other; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
In the present invention, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.
The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. In order to simplify the present disclosure, components and arrangements of specific examples are described below. They are, of course, merely examples and are not intended to limit the invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, which are for the purpose of brevity and clarity, and which do not themselves indicate the relationship between the various embodiments and/or arrangements discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the application of other processes and/or the use of other materials.
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by a person skilled in the art without making any inventive effort, are intended to be within the scope of the present invention.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise. Meanwhile, in the description of the present invention, the terms "first", "second", and the like are used only to distinguish the description, and are not to be construed as indicating or implying relative importance.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a thin film bulk acoustic resonator according to the present invention. The thin film bulk acoustic resonator includes:
a substrate 100, wherein a first groove is formed on the top of the substrate 100;
the supporting layer 200, the supporting layer 200 is an upper layer of the substrate 100 and forms a cavity 110 with the first groove;
a bottom electrode layer 300, the bottom electrode layer 300 being an upper layer of the support layer 200;
a piezoelectric layer 400, the piezoelectric layer 400 being an upper layer of the bottom electrode layer 300;
a top electrode layer 500, the top electrode layer 500 being an upper layer of the piezoelectric layer 400; the upper surface of the top electrode layer 500 is dug with a circle of second grooves 510, the second grooves 510 divide the upper surface of the top electrode layer 500 into a load part 520 and a gradient part 530, and the load part 520 is located at the contour edge of the top electrode layer 500 and surrounds the gradient part 530.
With reference to fig. 5, 8 and 9, a specific implementation example will be listed below, based on the present embodiment:
wherein, the manufacturing material of the substrate 100 is silicon dioxide, and the thickness of the substrate 100 is 575 μm; the depth of the first groove is 25um; the supporting layer 200 is made of silicon dioxide material, and the thickness of the supporting layer 200 is 3.5 μm; the bottom electrode layer 300 is made of molybdenum (Mo), and the thickness of the bottom electrode layer 300 is 800nm; the piezoelectric layer 400 is made of single-crystal aluminum nitride, the thickness of the piezoelectric layer 400 is 500nm, the top electrode layer 500 is made of molybdenum, and the thickness of the top electrode layer 500 is 800nm; a circle of second grooves 510 (the cross-sectional shape of the second grooves 510 in the width direction is an inverted triangle) is dug on the upper surface of the top electrode layer 500 to divide the load part 520 and the gradient part 530, and the load part 520 is located at the contour edge of the top electrode layer 500 and surrounds the gradient part 530.
The resonance points of the thin film bulk acoustic resonator under this specification were 2411MHz and 2490MHz, and the q value (quality coefficient) was 3330.
Referring to fig. 3, a first specific comparative example will be listed below:
the materials and parameters of the substrate 100, the first groove, the supporting layer 200, the bottom electrode layer 300, the piezoelectric layer 400, and the top electrode layer 500 are the same as those of the above embodiment example, and only the load portion 520 is divided, and the gradient portion 530 is absent, i.e. the region surrounded by the load portion 520 is all the region of the second groove 510.
Referring to fig. 6, 8 and 10, in the absence of the gradient taper portion 530, a large number of sub-resonance peaks (hetero peaks, mainly measured TE vibration modes) appear in the resonance region of the thin film bulk acoustic resonator of the first comparative example, compared to the embodiment example;
the thin film bulk acoustic resonator of the first comparative example has a significant increase in parasitic parameter compared to the implementation example, and obviously has a reduced ability to suppress parasitic resonance.
The resonance points of the thin film bulk acoustic resonator of the first comparative example were 2408MHz and 2424MHz, and the Q value was 2700, which is obviously lower than that of the implementation example, so that it was confirmed that the gradient gradually changing portion 530 can effectively raise the Q value of the thin film bulk acoustic resonator.
Referring to fig. 4, a second specific comparative example will be listed below:
the materials and parameters for manufacturing the substrate 100, the first groove, the support layer 200, the bottom electrode layer 300, the piezoelectric layer 400, and the top electrode layer 500 are the same as those of the above embodiment example, and only the gradient graded portion 530 is divided, and the load portion 520 is absent, i.e., the gradient graded portion 530 is surrounded by the second groove 510.
Referring to fig. 7, 8 and 11, in the absence of the load part 520, the second comparative example has a resonance region in which sub-resonance peaks appear significantly, but in a smaller number than the first comparative example;
the parasitic parameters of the thin film bulk acoustic resonator of the second comparative example were increased compared to the implementation example, but the amplification was smaller than that of the thin film bulk acoustic resonator of the first comparative example.
Therefore, the load part 520 can be separated and matched with the second groove 510, the secondary resonance wave crest can be effectively restrained, and the energy of the TE vibration mode can be more conveniently released from the boundary of the film bulk acoustic resonator, so that the purpose of weakening parasitic resonance is achieved.
The film bulk acoustic resonator of the second comparative example had resonance points 2408MHz and 2424MHz and q-value 1900, which was significantly lower than that of the first comparative example.
As can be confirmed from the above embodiments, the gradient gradually changing portion 530 can effectively inhibit the TE vibration mode, and meanwhile, the load portion 520 cooperates with the second groove 510 to reduce the degree of mismatch of acoustic impedances outside the central area and the resonance area of the thin film bulk acoustic resonator, so that energy of the TE vibration mode is more conveniently released from the boundary of the thin film bulk acoustic resonator, thereby achieving the purpose of weakening parasitic resonance.
It should be noted that, in practice, since the load portion 520 and the gradient portion 530 are formed by dividing the top electrode layer 500 by the second groove 510, it can be understood that the top electrode layer 500 includes the load portion 520, the gradient portion 530, and the second groove 510.
However, since the loading part 520, the gradient part 530, and the second groove 510 need to be processed, it is required that the top electrode layer 500 is reserved with a sufficient thickness, and the thickness of the top electrode layer 500 may be the same as or different from that of the bottom electrode layer 300.
In some embodiments, the depth of the first recess is less than 30um.
In the process of manufacturing the thin film bulk acoustic resonator, the first groove needs to be filled with the sacrificial layer material, and then the sacrificial layer is manufactured, when the supporting layer 200 is manufactured or the thin film bulk acoustic resonator is manufactured, the sacrificial layer material needs to be released (the releasing process belongs to the prior art and is not described in detail here), so that the cavity 110 can be smoothly constructed, and the supporting capability of the substrate 100 is weakened due to the thickness reduction of the supporting effect provided by the substrate 100 caused by the first groove, so that the depth of the first groove is not too deep, and the influence on the service life of the thin film bulk acoustic resonator is avoided.
It should be noted that, the purpose of the cavity 110 is to form the required total reflection of the sound wave, and the design of the cavity 110 is a conventional design, which is not described herein. However, the cavity 110 is provided, so that the support layer 200 is mainly provided for supporting each superstructure, preventing the superstructure from collapsing, and ensuring that the superstructure is manufactured smoothly as a basis for the superstructure.
In some embodiments, referring to fig. 1, the second groove 510 has an inverted triangle cross-sectional shape in the width direction, that is, the gradient portion 530 has a trapezoid shape, which is most capable of suppressing the TE vibration mode.
In some embodiments, the substrate 100 is made of any one of silicon, silicon compound, sapphire, liGaO2, and metal.
In some embodiments, the bottom electrode layer 300 is made of any one of Al, mo, W, pt, ti, au or a combination of any of a plurality of materials.
In certain embodiments, the top electrode layer 500 is made of any one of Al, mo, W, pt, ti, au or a combination of any of a plurality of materials.
In some embodiments, the piezoelectric layer 400 is made of single crystal aluminum nitride, polycrystalline aluminum nitride, zinc oxide, lead zirconate titanate, BST, liNbO 3 Any one of the following.
Referring to fig. 12, fig. 12 is a flowchart of a method for manufacturing the thin film bulk acoustic resonator in the above embodiment. The preparation method comprises the following steps:
s1, obtaining a cleaned substrate;
s2, etching a first groove on the cleaned substrate based on a dry etching process;
s3, filling a sacrificial layer material in the first groove to obtain a sacrificial layer, wherein the top surface of the sacrificial layer is flush with the top surface of the substrate;
s4, manufacturing a supporting layer on the top surface of the sacrificial layer based on a PECVD method; the supporting layer covers the top surface of the substrate;
s5, manufacturing a bottom electrode layer on the top surface of the supporting layer based on a magnetron sputtering method;
s6, manufacturing a piezoelectric layer on the top surface of the bottom electrode layer based on a magnetron sputtering method;
s7, manufacturing a top electrode layer on the top surface of the piezoelectric layer based on a magnetron sputtering method;
s8, etching a second groove on the top surface of the top electrode layer based on a dry etching process to manufacture a load part and a gradient gradual change part.
Specifically, specific processing examples will be listed below with respect to the above-described implementation examples:
in step S2, a dry etching process is performed using an existing Inductively Coupled Plasma (ICP) etcher,the device parameters are adjusted as follows: ICP coil power of 1500W, etching chamber temperature of 10 ℃, etching chamber pressure of 5mTorr, -substrate bias voltage of 400V; requiring a volume flow of 70cm 3 Cl/min 2 The volume flow is 50cm 3 BCl/min 3 And a volume flow of 30cm 3 And carrying out dry etching under Ar condition of/min to obtain the first groove.
In step S3, the sacrificial layer material may be PSG (phosphosilicate glass), and after filling the first recess, the redundant sacrificial layer material is removed by Chemical Mechanical Polishing (CMP), so that the sacrificial layer height and the top of the first recess are in the same plane.
In step S4, a silicon dioxide support layer is prepared using a PECVD method (plasma enhanced chemical vapor deposition method).
In step S5, a layer of metal molybdenum is deposited on the top surface of the supporting layer by sputtering by adopting the existing direct current vacuum magnetron sputtering coating machine to serve as a bottom electrode layer.
In step S6, a layer of single-crystal aluminum nitride is deposited on the top surface of the bottom electrode layer by adopting the existing direct-current vacuum magnetron sputtering coating machine as a piezoelectric layer, and the parameters of equipment are adjusted as follows: 5*10 -7 Slide chamber pressure of Torr, power supply of 6kw, ar feed rate of 10sccm, N of 45sccm 2 At the speed, the single-crystal aluminum nitride is grown by sputtering under the condition, and the sputtering gas is high-purity N of 99.9999 percent 2 And Ar, the sputtering target is 99.999% high-purity Al. It should be noted that, before sputter growth, sputter target needs to be sputter cleaned for 10 minutes (specifically, in the prior art, the description is omitted here).
In step S7, the specific steps in step S7 include:
s71, sequentially coating adhesion promoters and photoresist on the top surface of the piezoelectric layer;
s72, exposing the coated piezoelectric layer by using ultraviolet light;
s73, performing sputter deposition on the top surface of the exposed piezoelectric layer based on a magnetron sputtering method so as to manufacture a top electrode layer on the top surface of the piezoelectric layer;
s74, soaking the sputtered and deposited piezoelectric layer and the top electrode layer in acetone to strip the unexposed photoresist.
In step S8, the existing inductively coupled plasma etching machine is used to perform a triangular etching process, and the parameters of the equipment are adjusted as follows: ICP coil power of 1130W, etching chamber temperature of 7 ℃, etching chamber pressure of 5mTorr, -substrate bias voltage of 400V; requiring a volume flow of 70cm 3 Cl/min 2 The volume flow is 50cm 3 BCl/min 3 And a volume flow of 30cm 3 And carrying out dry triangular etching under Ar condition of/min to obtain a second groove, and simultaneously dividing a load part and a gradient gradual change part.
In certain embodiments, the specific steps in step S1 comprise:
s11, obtaining a substrate to be cleaned;
s12, washing a substrate to be cleaned by sequentially using acetone and anhydrous ethanol;
s13, using the first mixed solution and the second mixed solution to clean the substrate after washing for the first time; the first mixed solution is prepared by mixing sulfuric acid, hydrogen peroxide and water in a ratio of 3:1:1; the second mixed solution is prepared by mixing hydrogen fluoride and water in a ratio of 1:10;
s14, performing second cleaning on the substrate subjected to the first cleaning by using ionized water;
s15, drying the substrate subjected to the second cleaning for the first time;
s16, cleaning the substrate after the first drying for the third time by using a hydrogen fluoride solution with the concentration of 1.5%;
s17, drying the substrate subjected to the third cleaning for the second time to obtain the cleaned substrate.
In the implementation, the oxide and the pollution particles on the surface of the substrate are effectively removed through the steps, so that the manufactured film bulk acoustic resonator can be ensured to be normally used.
In this document, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.
The description of the terms "one embodiment," "certain embodiments," "an exemplary embodiment," "an example," "a particular example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The above description is only an example of the present invention and is not intended to limit the scope of the present invention, and various modifications and variations will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A thin film bulk acoustic resonator, comprising:
a substrate (100), wherein a first groove is formed on the top of the substrate (100);
a support layer (200), wherein the support layer (200) is an upper layer of the substrate (100) and forms a cavity (110) with the first groove;
a bottom electrode layer (300), the bottom electrode layer (300) being an upper layer of the support layer (200);
a piezoelectric layer (400), the piezoelectric layer (400) being an upper layer of the bottom electrode layer (300);
a top electrode layer (500), the top electrode layer (500) being an upper layer of the piezoelectric layer (400); the upper surface of the top electrode layer (500) is dug with a circle of second grooves (510), the second grooves (510) divide the upper surface of the top electrode layer (500) into a load part (520) and a gradient gradual change part (530), and the load part (520) is positioned at the contour edge of the top electrode layer (500) and surrounds the gradient gradual change part (530).
2. The thin film bulk acoustic resonator of claim 1, wherein the depth of the first recess is less than 30um.
3. The thin film bulk acoustic resonator according to claim 1, characterized in that the cross-sectional shape of the second groove (510) in the width direction is an inverted triangle.
4. The thin film bulk acoustic resonator according to claim 1, wherein the substrate (100) is made of any one of silicon, silicon compound, sapphire, liGaO2, and metal.
5. The thin film bulk acoustic resonator according to claim 1, characterized in that the bottom electrode layer (300) is made of any one material or a combination of any multiple materials of Al, mo, W, pt, ti, au.
6. The thin film bulk acoustic resonator according to claim 1, characterized in that the top electrode layer (500) is made of any one material or a combination of any multiple materials of Al, mo, W, pt, ti, au.
7. The thin film bulk acoustic resonator according to claim 1, characterized in that the piezoelectric layer (400) is made of single crystal aluminum nitride, polycrystalline aluminum nitride, zinc oxide, lead zirconate titanate, BST, liNbO 3 Any one of the following.
8. A method for producing the thin film bulk acoustic resonator as claimed in claim 1, characterized by comprising the steps of:
s1, obtaining a cleaned substrate;
s2, etching the first groove on the cleaned substrate based on a dry etching process;
s3, filling a sacrificial layer material in the first groove to obtain a sacrificial layer, wherein the top surface of the sacrificial layer is flush with the top surface of the substrate;
s4, manufacturing the supporting layer on the top surface of the sacrificial layer based on a PECVD method; the supporting layer covers the top surface of the substrate;
s5, manufacturing the bottom electrode layer on the top surface of the supporting layer based on a magnetron sputtering method;
s6, manufacturing the piezoelectric layer on the top surface of the bottom electrode layer based on a magnetron sputtering method;
s7, manufacturing the top electrode layer on the top surface of the piezoelectric layer based on a magnetron sputtering method;
s8, etching the second groove on the top surface of the top electrode layer based on a dry etching process to manufacture the load part and the gradient gradual change part.
9. The method according to claim 8, wherein the specific steps in step S1 include:
s11, obtaining a substrate to be cleaned;
s12, washing the substrate to be cleaned with acetone and absolute ethyl alcohol in sequence;
s13, using the first mixed solution and the second mixed solution to clean the substrate after washing for the first time; the first mixed solution is prepared by mixing sulfuric acid, hydrogen peroxide and water in a ratio of 3:1:1; the second mixed solution is prepared by mixing hydrogen fluoride and water in a ratio of 1:10;
s14, performing second cleaning on the substrate subjected to the first cleaning by using ionized water;
s15, drying the substrate subjected to the second cleaning for the first time;
s16, cleaning the substrate after the first drying for the third time by using a hydrogen fluoride solution with the concentration of 1.5%;
s17, drying the substrate subjected to the third cleaning for the second time to obtain the cleaned substrate.
10. The method according to claim 8, wherein the specific steps in step S7 include:
s71, sequentially coating adhesion promoters and photoresist on the top surface of the piezoelectric layer;
s72, exposing the coated piezoelectric layer by using ultraviolet light;
s73, performing sputter deposition on the top surface of the exposed piezoelectric layer based on a magnetron sputtering method so as to manufacture the top electrode layer on the top surface of the piezoelectric layer;
s74, soaking the sputtered and deposited piezoelectric layer and the top electrode layer in acetone to strip the unexposed photoresist.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104767500A (en) * | 2014-01-03 | 2015-07-08 | 李国强 | Cavity film bulk acoustic resonator and preparation method thereof |
| CN107809221A (en) * | 2017-09-27 | 2018-03-16 | 佛山市艾佛光通科技有限公司 | A kind of cavity type FBAR and preparation method thereof |
| US20180191327A1 (en) * | 2017-01-03 | 2018-07-05 | Win Semiconductors Corp. | Bulk acoustic wave filter and a method of frequency tuning for bulk acoustic wave resonator of bulk acoustic wave filter |
| CN111262551A (en) * | 2020-04-01 | 2020-06-09 | 河源市众拓光电科技有限公司 | Air-gap type shear wave resonator based on lithium niobate thin film and preparation method thereof |
| CN112039463A (en) * | 2019-08-09 | 2020-12-04 | 中芯集成电路（宁波）有限公司 | Method for manufacturing film bulk acoustic resonator |
| US20220103147A1 (en) * | 2021-11-26 | 2022-03-31 | Newsonic Technologies | Lithium niobate or lithium tantalate fbar structure and fabricating method thereof |
| CN116131798A (en) * | 2022-11-22 | 2023-05-16 | 河源市艾佛光通科技有限公司 | Solid-state bulk acoustic wave resonator and manufacturing method thereof |
-
2023
- 2023-07-06 CN CN202310824876.7A patent/CN116545402A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104767500A (en) * | 2014-01-03 | 2015-07-08 | 李国强 | Cavity film bulk acoustic resonator and preparation method thereof |
| US20180191327A1 (en) * | 2017-01-03 | 2018-07-05 | Win Semiconductors Corp. | Bulk acoustic wave filter and a method of frequency tuning for bulk acoustic wave resonator of bulk acoustic wave filter |
| CN107809221A (en) * | 2017-09-27 | 2018-03-16 | 佛山市艾佛光通科技有限公司 | A kind of cavity type FBAR and preparation method thereof |
| CN112039463A (en) * | 2019-08-09 | 2020-12-04 | 中芯集成电路（宁波）有限公司 | Method for manufacturing film bulk acoustic resonator |
| CN111262551A (en) * | 2020-04-01 | 2020-06-09 | 河源市众拓光电科技有限公司 | Air-gap type shear wave resonator based on lithium niobate thin film and preparation method thereof |
| US20220103147A1 (en) * | 2021-11-26 | 2022-03-31 | Newsonic Technologies | Lithium niobate or lithium tantalate fbar structure and fabricating method thereof |
| CN116131798A (en) * | 2022-11-22 | 2023-05-16 | 河源市艾佛光通科技有限公司 | Solid-state bulk acoustic wave resonator and manufacturing method thereof |
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