CN115021709A - Thin film mechanical wave resonator and manufacturing method thereof - Google Patents
Thin film mechanical wave resonator and manufacturing method thereof Download PDFInfo
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Images
Classifications
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- 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
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02007—Details of bulk acoustic wave devices
- H03H9/02086—Means for compensation or elimination of undesirable effects
-
- 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 a film mechanical wave resonator and a manufacturing method thereof, wherein the film mechanical wave resonator comprises a resonator body and a cap layer, wherein the resonator body comprises a substrate, a groove structure and a sandwich structure; the groove structure is arranged on the first surface of the substrate, a sacrificial material layer is filled in the groove structure, the sacrificial material layer can be released to form a cavity area of the groove structure, the sandwich structure comprises a bottom electrode, a piezoelectric layer and an upper electrode which are sequentially arranged from bottom to top, and the bottom electrode is arranged above the sacrificial material layer; and the cover cap layer is bonded on the resonator body, wherein one side of the cover cap layer close to the resonator body is provided with wiring metal. The invention improves the reliability problem of the device by optimizing the bonding method, and ensures the performance of the resonator; meanwhile, the conventional processing and preparation method of the cap layer is changed, so that the wiring metal is far away from an external device as far as possible, the parasitic problem of connection between the wiring metal and the substrate is further reduced, and the wiring metal has the advantages of high reliability, low parasitic clutter and the like.
Description
Technical Field
The invention relates to the technical field of processing and manufacturing of semiconductor devices, in particular to a thin film mechanical wave resonator and a manufacturing method thereof.
Background
In recent years, communication technology is rapidly developed, technology updating is accelerated, particularly the popularization of a 5G frequency band, and filters needed by a radio frequency front end become more and more; taking a transceiver end of a handset as an example, tens of filters are required to ensure the transmission and reception of signals. Meanwhile, the radio frequency acoustic wave duplex filter is rapidly increased in the communication market, and technologies including a Surface Acoustic Wave (SAW) device and a film bulk acoustic wave (FBAR) device are rapidly improved; the development of communication technology has increased the requirements for filters, and the requirements for large bandwidth, high power and high frequency have presented a great challenge for acoustic wave devices. The filter is required to have low insertion loss and high rectangular coefficient performance, and also has high requirements on temperature characteristics, linearity and the like.
Film Bulk Acoustic Resonators (FBARs) are one of the most suitable filters for 5G applications due to their small size, low insertion loss, large out-of-band rejection, high quality factor, high operating frequency, large power capacity, and good anti-electrostatic shock capability. The film bulk acoustic resonator comprises two film electrodes, a piezoelectric film layer is arranged between the two film electrodes, the working principle of the film bulk acoustic resonator is that the piezoelectric film layer generates vibration under an alternating electric field, the vibration excites bulk acoustic waves which are transmitted along the thickness direction of the piezoelectric film layer, the acoustic waves are transmitted to the interface of the upper electrode and the lower electrode and air and are reflected back, and then the sound waves are reflected back and forth in the film to form oscillation. When the sound wave is transmitted in the piezoelectric film layer and is just odd times of half wavelength, standing wave oscillation is formed. The FBAR filter is processed by adopting an MEMS process, and can realize a narrow-band device with low insertion loss and high rectangular coefficient by utilizing the piezoelectric property. However, the frequency characteristics are limited, and the suppression of frequencies far away from the passband cannot be formed independently, so that the design performance needs to be met by combining with an external circuit design, usually by combining with a corresponding substrate design;
the conventional FBAR device is prepared by forming a micro cap layer on a wafer of an FABR device through Wafer Level Packaging (WLP), further forming a closed environment on the FBAR device, leading out an FBAR electrode through a Through Silicon Via (TSV) and the like, routing certain metal wiring on the leading-out surface, connecting the FBAR electrode with the outside through a copper roller or a solder ball technology and the like, and solving some parasitic problems after being combined with an external circuit, so that the passband and out-of-band rejection shift phenomena are particularly obvious at high frequency; meanwhile, the FBAR device prepared at present has some reliability problems (water vapor leakage and the like), especially some processes using adhesion modes such as dry film and the like for packaging, so that the requirement of a high-performance radio frequency system cannot be met.
Disclosure of Invention
In view of the above, it is desirable to provide a thin film mechanical wave resonator and a method for manufacturing the same.
A thin film mechanical wave resonator comprises a resonator body and a cap layer, wherein the resonator body comprises a substrate, a groove structure and a sandwich structure;
the groove structure is arranged on the first surface of the substrate, a sacrificial material layer is filled in the groove structure, and the sacrificial material layer can be released to form a cavity area of the groove structure;
the sandwich structure comprises a bottom electrode, a piezoelectric layer and an upper electrode which are sequentially arranged from bottom to top, wherein the bottom electrode is arranged above the sacrificial material layer;
the cover cap layer is bonded on the resonator body, wherein one side, close to the resonator body, of the cover cap layer is provided with wiring metal.
In one embodiment, a heat dissipation protection layer is deposited on the surface of the substrate, the heat dissipation protection layer covers the groove structure, and the heat dissipation protection layer can provide protection for the substrate when the sacrificial material layer is released and increase a heat dissipation path.
In one embodiment, a hard dielectric layer is disposed between the sacrificial material layer and the bottom electrode.
A method of manufacturing a thin film mechanical wave resonator, comprising the steps of:
s1, etching the first surface of the substrate to form a groove structure, and depositing a heat dissipation protective layer;
s2, filling a sacrificial material layer in the groove structure;
s3, depositing a sandwich structure above the sacrificial material layer;
s4, releasing the filled sacrificial material layer to form a resonator body;
and S5, bonding the cap layer on the resonator body.
In one embodiment, the step S1 includes:
s11, forming a groove structure on the first surface of the substrate through etching, and enabling the side wall of the groove structure to be an inclined plane;
and S12, depositing a dielectric layer or a metal layer on the upper surface of the substrate and the inner surface of the groove structure to form a heat dissipation protective layer.
In one embodiment, the step S2 includes:
s21, filling a sacrificial material layer in the groove structure and on the upper surface of the heat dissipation protective layer;
s22, polishing the sacrificial material layer to be level with the height of the upper surface of the substrate through a grinding and polishing technology;
and S23, growing a dielectric layer on the upper surface of the substrate, wherein the dielectric layer covers the upper surface of the sacrificial material layer.
In one embodiment, the step S3 includes:
s31, depositing a bottom electrode on the dielectric layer, and patterning the bottom electrode by an etching method;
s32, etching the patterned edge of the bottom electrode above the sacrificial material layer with a gentle slope structure to form an inclined edge with a certain angle;
s33, depositing a piezoelectric layer on the bottom electrode and patterning the piezoelectric layer, wherein the patterned area of the piezoelectric layer is larger than the resonance area;
s34, depositing an upper electrode on the piezoelectric layer and patterning the upper electrode;
and S35, depositing a first connecting metal to connect the upper electrode to the same height as the bottom electrode.
In one embodiment, the step S31 is preceded by:
s30, depositing a piezoelectric seed layer in advance below the bottom electrode, wherein the piezoelectric seed layer is located on the upper surface of the dielectric layer.
In one embodiment, the step S4 includes:
s41, releasing the sacrificial material layer from the release hole by a dry method, a wet method or a dry-wet mixed method, so that a cavity is formed inside the groove structure;
s42, cleaning the cavity to remove water vapor residues;
and S43, carrying out passivation protection treatment on the surface of the resonator body.
In one embodiment, the step S5 includes:
s51, depositing a second connecting metal for the capping layer packaging; and a surface formed with a specific pattern structure;
s52, preparing a cap layer, and arranging a wiring metal on one side of the cap layer close to the resonator body;
s53, connecting the connecting pins to the other side of the cap layer through a backside punching technology, and leading the signal out of the outside;
and S54, bonding the cap layer and the resonator body.
According to the film mechanical wave resonator and the manufacturing method thereof, the high-performance resonator body is prepared on the substrate by adopting the technology of the sacrificial material layer, and then the reliability problem of the device is improved by optimizing the bonding method, so that the performance of the resonator is ensured; meanwhile, the conventional processing and preparation method of the cap layer is changed, so that the wiring metal is far away from an external device as far as possible, the parasitic problem of connection between the wiring metal and the substrate is further reduced, and the wiring metal has the advantages of high reliability, low parasitic clutter and the like.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic diagram of the structure of a resonator body of the present invention;
FIG. 2 is a schematic structural diagram of a cap layer of the present invention;
fig. 3 is a schematic structural view of a thin film mechanical wave resonator of the present invention;
FIG. 4 is a schematic structural view of a thin film mechanical wave resonator of the present invention using another bonding pattern;
fig. 5 is a schematic view showing a structure of a thin film mechanical wave resonator of the present invention using still another bonding pattern.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
Referring to fig. 1 to 5, an embodiment of the present invention provides a thin film mechanical wave resonator, including a resonator body 1 and a cap layer 2, where the resonator body 1 includes a substrate 11, a trench structure 12, and a sandwich structure 13;
the groove structure 12 is arranged on the first surface of the substrate 11, the interior of the groove structure 12 is filled with a sacrificial material layer 14, and the sacrificial material layer 14 can be released to form a cavity region of the groove structure 12;
the sandwich structure 13 includes a bottom electrode 131, a piezoelectric layer 132 and an upper electrode 133, which are sequentially disposed from bottom to top, wherein the bottom electrode 131 is disposed above the sacrificial material layer 14;
the cap layer 2 is bonded on the resonator body 1, wherein a wiring metal is arranged on one side of the cap layer 2 close to the resonator body 1.
In this embodiment, the substrate 11 may be any suitable substrate commonly used in the art, and may be at least one of the following materials: silicon (Si) \\ silicon carbide (SiC), germanium (Ge), gallium arsenide (GaAs), indium phosphide (InP), or other group iii/v compound semiconductors, the substrate 11 requires a characteristic of high resistance, and the present invention is preferably a high-resistance silicon substrate. The cap layer 2 may be silicon, glass, or organic thin film, and the silicon is preferably used as the cap layer in the present invention.
In an embodiment of the present invention, a heat dissipation protection layer 15 is deposited on the surface of the substrate 11, the heat dissipation protection layer 15 covers the groove structure 12, and the heat dissipation protection layer 15 can provide protection for the substrate 1 when the sacrificial material layer 14 is released and increase a heat dissipation path.
In an embodiment of the present invention, a hard dielectric layer 16 is disposed between the sacrificial material layer 14 and the bottom electrode 131.
An embodiment of the present invention provides a method for manufacturing a thin film mechanical wave resonator, including the steps of:
s1, etching the first surface of the substrate 11 to form a groove structure 12, and depositing a heat dissipation protective layer 15;
s2, filling the groove structure 12 with a sacrificial material layer 14;
s3, depositing a sandwich structure 13 on the sacrificial material layer 14;
s4, releasing the filled sacrificial material layer 14 to form a resonator body;
and S5, bonding the cap layer 2 on the resonator body.
In an embodiment of the present invention, the step S1 includes:
s11, forming a groove structure 12 on the first surface of the substrate 11 through etching, and enabling the side wall of the groove structure 12 to be an inclined plane; in this embodiment, the depth of the groove structure 12 is typically several micrometers, and the groove structure 12 may be formed by etching on the high-resistance silicon substrate 11 through a dry process or a wet process. While the side walls of the groove structure 12 are arranged as oblique sides (which may be trapezoidal structures), mainly to reduce the problem of stress concentration.
And S12, depositing a dielectric layer or a metal layer on the upper surface of the substrate 11 and the inner surface of the groove structure 12 to form a heat dissipation protective layer 15. In this embodiment, the heat dissipation protection layer 15 is used to protect the substrate 1 and increase heat dissipation when the sacrificial material layer 14 in the groove structure 12 is subsequently released, and the dielectric layer or the metal layer is a material having a high selection ratio for releasing the sacrificial material layer 14 and a high coefficient of thermal conductivity.
In an embodiment of the present invention, the step S2 includes:
s21, filling the sacrificial material layer 14 in the groove structure 12 and on the upper surface of the heat dissipation protection layer 15;
s22, polishing the sacrificial material layer 14 to be flush with the height of the upper surface of the substrate 11 through a grinding and polishing technology; thus, the surface roughness of the sacrificial material layer 14 can be ensured to be small, and the surface root mean square roughness is generally less than 0.5nm, so that the crystal quality of the subsequently deposited dielectric layer 16 can be improved.
And S23, growing a dielectric layer 16 on the upper surface of the substrate 11, wherein the dielectric layer 16 covers the upper surface of the sacrificial material layer 14.
In this embodiment, the material of the sacrificial material layer 4 includes phosphosilicate glass, low-temperature silicon dioxide, borophosphosilicate glass, germanium, carbon, polyimide or photoresist, and the sacrificial material layer may be formed by a deposition process or a spin-on process according to the material. The dielectric layer 16 can protect the mechanical structure stability after the sacrificial material layer 14 is released, and the dielectric layer 16 can be any suitable dielectric material, including but not limited to silicon oxide, silicon carbide, silicon nitride, silicon oxynitride, silicon carbonitride, and other materials.
In an embodiment of the present invention, the step S3 includes:
s31, depositing a bottom electrode 131 on the dielectric layer 16, and patterning the bottom electrode 131 by an etching method;
s32, etching the patterned edge of the bottom electrode 131 above the sacrificial material layer 14 with a gentle slope structure to form an inclined edge with a certain angle; thus, the stress concentration problem is avoided;
s33, depositing and patterning a piezoelectric layer 132 on the bottom electrode 131, and making the patterned area of the piezoelectric layer 132 larger than the resonance area;
s34, depositing and patterning an upper electrode 133 on the piezoelectric layer 132;
s35, depositing a first connection metal 134 to connect the top electrode 133 to the same height as the bottom electrode 131. In this embodiment, a thicker first connection metal 134 may be deposited by PVD/CVD or electroplating, and then the first connection metal 134 is patterned, and only the connection portion and the portion for the micro-package region are reserved, and meanwhile, the portion for the package connection portion is etched to form a rougher region; the first connection metal 134 may be a metal having excellent electrical conductivity, such as copper, gold, or aluminum.
In this embodiment, the bottom electrode 131 is made of a high acoustic impedance material, and may be made of metal such as molybdenum, aluminum, titanium, tungsten, gold, platinum, etc., and the deposition thickness is generally between several hundred nanometers and several micrometers. A molybdenum electrode may be preferred, and a molybdenum electrode with a certain thickness is deposited by means of PVD.
The piezoelectric layer 132 is typically aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), lithium niobate (LiNbO) 3 ) Or lithium tantalate (LiTaO) 3 ) When the piezoelectric film is deposited by a PVD or CVD method, the thickness is generally about several hundred nanometers to several micrometers, the quality of the piezoelectric film crystal is better, the performance of the prepared resonator is better, and the preparation method needs to be combined with comprehensive selection such as cost efficiency. The piezoelectric layer 132 is the main propagation region of the acoustic wave inDuring patterning, attention needs to be paid to etching at the edge, and a general patterning area needs to be larger than a resonance area, so that performance deterioration caused by sound wave scattering due to rough edge etching is avoided. In this embodiment, the upper electrode 133 is introduced to the bottom electrode 131 at the same height, and this step requires the piezoelectric layer 132 to be etched to be slope-shaped, so as to ensure the connection integrity of the upper electrode 133; in other embodiments of the present invention, the metal wire may be etched to be vertical, and then the metal wire may be thickened.
In addition, the upper electrode 133 in this embodiment may be made of a metal material with special properties, including but not limited to magnetoelectric metal, wave-absorbing metal, etc., in the same manner as the bottom electrode 131; then, the upper electrode 133 is patterned, and may have a circular, rectangular, or polygonal shape.
In the present invention, the overlapping area of the upper electrode 133/the piezoelectric layer 132/the bottom electrode 131 is the resonance area, and meanwhile, it is to be noted that the anchor area (the upper electrode 133/the piezoelectric layer 132/the bottom electrode 131/the substrate 11) is reduced as much as possible, and the overlapping area may be performed in a staggered manner, or an air layer or a low dielectric material is inserted between the piezoelectric layer 132 and the electrode in the prior art, so as to avoid the energy leakage to the substrate 11; meanwhile, the edge member of the upper electrode 133 has a frame-like structure, so that the lateral leakage of the acoustic wave can be prevented.
In an embodiment of the present invention, the step S31 includes:
s30, pre-depositing a piezoelectric seed layer 135 under the bottom electrode 131, wherein the piezoelectric seed layer 135 is located on the upper surface of the dielectric layer 16. In this embodiment, a magnetron sputtering method is adopted to deposit a piezoelectric film with a preferred orientation, the requirement on the substrate 11 is better, and the piezoelectric seed layer 135 is deposited in advance before the molybdenum electrode deposition, so that the quality of the subsequently deposited crystals can be optimized.
In an embodiment of the present invention, the step S4 includes:
s41, releasing the sacrificial material layer 14 from the release hole by a dry method, a wet method or a dry and wet mixed method, so that a cavity is formed inside the groove structure 12;
s42, cleaning the cavity to remove water vapor residues;
and S43, carrying out passivation protection treatment on the surface of the resonator body 1.
In this embodiment, the filled sacrificial material layer 14 is released, and an energy reflection interface of the film bulk acoustic resonator is formed in the groove structure 12; meanwhile, a subsequent cleaning process is required to avoid water vapor and the like caused by a release process, so that the cleanliness of the cavity is ensured; the passivation treatment is performed on the surface of the resonator body 1 to prevent contamination of the external environment.
In an embodiment of the present invention, the step S5 includes:
s51, depositing a second connecting metal 17 for encapsulating the cap layer 2; and a surface formed with a specific pattern structure; the second connecting metal 17 is generally a surrounding ring and a connected pad region, and a connecting metal and a bonding material with a specific pattern structure are formed by matching with the first connecting metal 134 so as to increase the bonding firmness; wherein, the bonding material can be metal, silicon oxide and the like;
s52, preparing a cap layer 2, and arranging a wiring metal on one side of the cap layer 2 close to the resonator body 1;
s53, connecting the other side of the cap layer 2 at the connecting pin through a back piercing technology, and leading out the signal to the outside;
and S54, bonding the cap layer 2 and the resonator body 1.
In this embodiment, a wiring metal is prepared on one side of the cap layer 2, and is used for laying out a circuit connecting trace (RDL) and a wiring of a bonding ring, and the metal used for the bonding ring may be a metal with a flat interface or a metal with a patterned surface structure corresponding to a device bonding metal; the invention takes the graphical bonding surface as an example for illustration, and the graphical bonding contact surface can increase the surface area of bonding contact, thereby improving the firmness of bonding.
The other side of the cap layer 2 is connected with the connecting pin through a backside punching technology, and a signal is led out of the outside; then, bonding the cap layer 2 and the resonator body 1 in a metal bonding mode, an adhesive bonding mode, a covalent bonding mode or a fusion bonding mode; namely, the wiring metal is positioned at one side close to the resonator body 1, so that the connection with an external substrate and other packaging structures can be kept away, and the parasitic interference of the RDL is reduced.
After bonding is completed, a copper pellet or a retainer ball connection mode may be performed externally, and then the wafer may be cut.
In summary, according to the thin film mechanical wave resonator and the manufacturing method thereof, the high-performance resonator body is prepared on the substrate 11 by adopting the technology of the sacrificial material layer 14, and then, the reliability problem of the device is improved by optimizing the bonding method, so that the performance of the resonator is ensured; meanwhile, the conventional processing and preparation method of the cap layer 2 is changed, so that the wiring metal is far away from an external device as far as possible, the parasitic problem of connection between the wiring metal and the substrate is further reduced, and the wiring metal has the advantages of high reliability, low parasitic clutter and the like.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above examples only represent several embodiments of the present invention, but should not be construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. The thin film mechanical wave resonator is characterized by comprising a resonator body and a cap layer, wherein the resonator body comprises a substrate, a groove structure and a sandwich structure;
the groove structure is arranged on the first surface of the substrate, a sacrificial material layer is filled in the groove structure, and the sacrificial material layer can be released to form a cavity area of the groove structure;
the sandwich structure comprises a bottom electrode, a piezoelectric layer and an upper electrode which are sequentially arranged from bottom to top, wherein the bottom electrode is arranged above the sacrificial material layer;
the cover cap layer is bonded on the resonator body, wherein one side, close to the resonator body, of the cover cap layer is provided with wiring metal.
2. The thin film mechanical wave resonator of claim 1, wherein a heat dissipation protective layer is deposited on a surface of the substrate, the heat dissipation protective layer covering the groove structure, the heat dissipation protective layer capable of providing protection to the substrate when the sacrificial material layer is released and increasing a heat dissipation path.
3. The thin film mechanical wave resonator according to claim 2, wherein a hard dielectric layer is provided between the sacrificial material layer and the bottom electrode.
4. A method of manufacturing a thin film mechanical wave resonator, comprising the steps of:
s1, etching the first surface of the substrate to form a groove structure, and depositing a heat dissipation protective layer;
s2, filling a sacrificial material layer in the groove structure;
s3, depositing a sandwich structure above the sacrificial material layer;
s4, releasing the filled sacrificial material layer to form a resonator body;
and S5, bonding the cap layer on the resonator body.
5. The method of manufacturing a thin film mechanical wave resonator according to claim 4, wherein the step S1 includes:
s11, forming a groove structure on the first surface of the substrate through etching, and enabling the side wall of the groove structure to be an inclined plane;
and S12, depositing a dielectric layer or a metal layer on the upper surface of the substrate and the inner surface of the groove structure to form a heat dissipation protective layer.
6. The method of manufacturing a thin film mechanical wave resonator according to claim 5, wherein the step S2 includes:
s21, filling a sacrificial material layer in the groove structure and on the upper surface of the heat dissipation protective layer;
s22, polishing the sacrificial material layer to be level with the height of the upper surface of the substrate through a grinding and polishing technology;
and S23, growing a dielectric layer on the upper surface of the substrate, wherein the dielectric layer covers the upper surface of the sacrificial material layer.
7. The method of manufacturing a thin film mechanical wave resonator according to claim 6, wherein the step S3 includes:
s31, depositing a bottom electrode on the dielectric layer, and patterning the bottom electrode by an etching method;
s32, etching the patterned edge of the bottom electrode above the sacrificial material layer with a gentle slope structure to form an inclined edge with a certain angle;
s33, depositing a piezoelectric layer on the bottom electrode and patterning the piezoelectric layer, wherein the patterned area of the piezoelectric layer is larger than the resonance area;
s34, depositing an upper electrode on the piezoelectric layer and patterning the upper electrode;
and S35, depositing a first connecting metal, and connecting the upper electrode to the same height as the bottom electrode.
8. The method of manufacturing a thin film mechanical wave resonator according to claim 7, wherein the step S31 is preceded by:
s30, depositing a piezoelectric seed layer in advance below the bottom electrode, wherein the piezoelectric seed layer is located on the upper surface of the dielectric layer.
9. The method of manufacturing a thin film mechanical wave resonator according to claim 8, wherein the step S4 includes:
s41, releasing the sacrificial material layer from the release hole by a dry method, a wet method or a dry-wet mixed method, so that a cavity is formed inside the groove structure;
s42, cleaning the cavity to remove water vapor residues;
and S43, carrying out passivation protection treatment on the surface of the resonator body.
10. The method of manufacturing a thin film mechanical wave resonator according to claim 9, wherein the step S5 includes:
s51, depositing a second connecting metal for the capping layer packaging; and a surface formed with a specific pattern structure;
s52, preparing a cap layer, and arranging a wiring metal on one side, close to the resonator body, of the cap layer;
s53, connecting the connecting pins to the other side of the cap layer through a backside punching technology, and leading the signal out of the outside;
and S54, bonding the cap layer and the resonator body.
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| CN117316909A (en) * | 2023-11-28 | 2023-12-29 | 北京七星华创微电子有限责任公司 | Electronic chip and preparation method thereof |
| CN117316909B (en) * | 2023-11-28 | 2024-02-27 | 北京七星华创微电子有限责任公司 | Electronic chip and preparation method thereof |
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