WO2024016095A1 - 一种滤波器单元及其制备方法、电子设备 - Google Patents

一种滤波器单元及其制备方法、电子设备 Download PDF

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Publication number
WO2024016095A1
WO2024016095A1 PCT/CN2022/106158 CN2022106158W WO2024016095A1 WO 2024016095 A1 WO2024016095 A1 WO 2024016095A1 CN 2022106158 W CN2022106158 W CN 2022106158W WO 2024016095 A1 WO2024016095 A1 WO 2024016095A1
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Prior art keywords
filter unit
substrate
modified
resonant
resonant structure
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PCT/CN2022/106158
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English (en)
French (fr)
Inventor
魏秋旭
李月
王立会
任艳飞
张韬楠
肖月磊
吴艺凡
冯昱霖
曹雪
韩基挏
安齐昌
常文博
李慧颖
曲峰
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京东方科技集团股份有限公司
北京京东方光电科技有限公司
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Priority to PCT/CN2022/106158 priority Critical patent/WO2024016095A1/zh
Publication of WO2024016095A1 publication Critical patent/WO2024016095A1/zh

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    • 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

Definitions

  • the present application relates to the technical field of radio frequency micro-electromechanical systems, and in particular to a filter unit and its preparation method, and electronic equipment.
  • FBAR thin film bulk acoustic resonator
  • air-gap FBAR is often produced by depositing a sacrificial layer.
  • the traditional sacrificial layer treatment process requirements are very strict, resulting in a very complicated preparation process for air-gap FBAR, which is not conducive to industrial production.
  • a filter unit including:
  • a substrate is provided on one side of the resonant structure, the substrate includes a modified structure and a support structure surrounding the modified structure, and a cavity is formed between the modified structure and the resonant structure.
  • the boundary of the orthographic projection of the resonance structure on the substrate overlaps with the support structure
  • the surface of the modified structure close to the resonance structure includes at least one arc surface.
  • the resonant structure includes at least one through hole, the through hole is connected to the cavity, and the boundary of the orthographic projection of the through hole on the substrate overlaps with the modified structure;
  • the geometric center of the space occupied by the through hole is collinear with the spherical center of the arc surface.
  • the spherical center of the arc surface is located at the connection between the through hole and the cavity.
  • the number of the arcuate surfaces is the same as the number of the through holes.
  • the surface of the support structure on the side close to the modified structure includes an annular surface
  • the shape of the space enclosed by the side of the annular surface close to the resonance structure includes a polygon with rounded corners, with The number of sides of the rounded polygon is the same as the number of through holes and the number of arcuate surfaces.
  • the resonant structure has five through holes
  • the surface of the modified structure close to the resonant structure includes five arcuate surfaces
  • the polygon with rounded corners includes a pentagon with rounded corners.
  • the distance between the connection points of the five arcuate surfaces and the resonant structure is smaller than the distance between the arcuate surface position corresponding to each of the through holes and the resonant structure.
  • the resonant structure has four through holes, the surface of the modified structure near the side of the resonant structure includes four arc surfaces, and the polygon with rounded corners includes a quadrilateral with rounded corners;
  • the resonant structure has three through holes
  • the surface of the modified structure close to the resonant structure includes three arc surfaces
  • the polygon with rounded corners includes a triangle with rounded corners.
  • the annular surface includes a connected first annular surface and a second annular surface, the second annular surface is located between the first annular surface and the resonant structure; a portion of the first annular surface In direct contact with the modified structure; the first annular surface and the second annular surface are not coplanar.
  • the space occupied by the first annular surface is smaller than the space occupied by the second annular surface.
  • the angle range between the second annular surface and the side of the resonant structure close to the substrate includes 80-88°.
  • the etching rate of the material of the modified structure is greater than the etching rate of the material of the support structure.
  • the filter unit further includes a support layer, the support layer being disposed between the modified structure and the resonant structure;
  • the through hole also penetrates the support layer and communicates with the cavity.
  • the material of the modified structure includes glass.
  • embodiments of the present application provide an electronic device, including at least three filter units as described above, at least two of the at least three filter units are connected in series, and are connected in series with all other filter units.
  • the filter units other than the filter unit are connected in parallel.
  • embodiments of the present application provide a method for manufacturing the above-mentioned filter unit, which method includes:
  • a resonance structure is formed on one side of the substrate; there is a cavity between the resonance structure and the substrate.
  • the forming the substrate includes:
  • the substrate is modified to form a modified part and a support structure; the support structure surrounds the modified part.
  • forming a resonant structure on one side of the substrate; having a cavity between the resonant structure and the substrate includes:
  • the etching liquid is injected through the through hole to corrode the modified part, forming a modified structure and a cavity between the modified structure and the resonance structure.
  • Figures 1 to 4 illustrate a preparation process of an air-gap FBAR in a related technology provided by an embodiment of the present application
  • Figure 5 is a schematic structural diagram of a filter unit provided by an embodiment of the present application.
  • Figure 6 is a top view of a modified structure in a filter unit provided by an embodiment of the present application.
  • Figure 7 is a perspective view of a substrate in a filter unit provided by an embodiment of the present application.
  • Figure 8 is a cross-sectional view of a substrate in a filter unit provided by an embodiment of the present application.
  • Figure 9 is a diagram showing various shapes of the surface of the side of the modified structure close to the resonant structure in a filter unit provided by the embodiment of the present application;
  • FIGS. 10 to 12 illustrate a preparation process of a filter unit provided by embodiments of the present application
  • Figure 13 is a schematic structural diagram of an electronic device provided by an embodiment of the present application.
  • FBAR as a new type of filter, has wide applications in 5G communications. According to the different device structures, FBAR can be divided into two categories: back-engraved type and air-gap type. Back-engraved FBAR has poor structural stability and low yield. Compared with back-engraved FBAR, air-gap FBAR has better mechanical reliability and is more widely used.
  • Current air-gap FBARs include a substrate and an electrode-piezoelectric film-electrode structure disposed on the substrate.
  • the piezoelectric effect converts electrical energy into mechanical energy, causing the piezoelectric film to mechanically deform, thereby exciting body acoustic waves within the body of the piezoelectric film.
  • try to make the sound waves form total reflection since the acoustic impedance of air can be considered to be approximately zero, when making an air-gap FBAR, both electrode surfaces must be in contact with the air.
  • an electrode far away from the substrate must be in contact with the air, while an electrode close to the substrate needs to be etched to remove at least part of the substrate material at the electrode, so that the electrode is grown on the substrate.
  • the electrode can not only be in contact with the air, but also ensure sufficient mechanical strength, thus creating an air-gap thin film bulk acoustic resonator.
  • FIG. 1 a groove 102 is formed on the surface of the single crystal silicon substrate 101 by etching.
  • silicon oxide or PSG phosphorus-doped silicon oxide is deposited at the groove to form a sacrificial layer.
  • the excess sacrificial layer 103 material is ground and polished through the CMP (Chemical Mechanical Polishing, Chemical Mechanical Polishing process) process to form a flat bottom structure; finally, as shown in Figure 4, on the surface with the sacrificial layer
  • CMP Chemical Mechanical Polishing, Chemical Mechanical Polishing process
  • the support layer 3 and the resonant structure 2 are sequentially stacked on the substrate, and then a through hole is formed on the resonant structure 3. Through the through hole, the corrosive liquid comes into contact with the sacrificial layer and then corrodes the sacrificial layer. After removing the sacrificial layer, the formation is as shown in Figure 4.
  • the cavity shown is an air gap type thin film bulk acoustic resonator in the related art.
  • the flatness requirements for the surface of the film treated by the above-mentioned CMP process are very strict, for example, the roughness of the surface of the film needs to be less than 0.5nm. , the depression caused by the CMP dishing effect is less than 50nm, etc. This will inevitably make the preparation process of the air-gap thin film bulk acoustic resonator complex and is not conducive to industrial production.
  • the filter unit includes: a resonant structure 2 .
  • the substrate 1 is arranged on one side of the resonant structure 2.
  • the substrate 1 includes a modified structure 11 and a support structure 12 surrounding the modified structure 11.
  • a cavity is formed between the modified structure 11 and the resonant structure 2.
  • the above resonant structure may include a first electrode 21 , a piezoelectric layer 22 and a second electrode 23 that are stacked in sequence.
  • a voltage such as AC
  • the piezoelectric effect converts electrical energy into mechanical energy, causing the piezoelectric layer 22 to undergo mechanical deformation, and then excites body acoustic waves in the piezoelectric layer 22.
  • the body acoustic waves are formed between the modified structure 11 and the resonant structure 2
  • the cavity vibrates and propagates.
  • the materials of the first electrode and the second electrode may include high acoustic resistance materials, such as molybdenum, tungsten, etc., for applying electrical signal excitation to the piezoelectric layer.
  • the thickness range of the above-mentioned first electrode and the second electrode along the direction perpendicular to the substrate may include 200-600 nm.
  • the thickness of the above-mentioned first electrode and the second electrode along the direction perpendicular to the substrate may both be 200 nm. , 400nm, 500nm, 600nm, etc.
  • the preparation process of the above-mentioned first electrode and the second electrode may include PVD (Physical Vapor Deposition, physical vapor deposition) and patterning.
  • the material of the piezoelectric layer may include aluminum nitride, aluminum scandium nitride, etc., and is used to receive electrical signal excitation generated by the two electrodes to form mechanical resonance.
  • the thickness of the piezoelectric layer along the direction perpendicular to the substrate may range from 500 to 2000 nm.
  • the thickness of the piezoelectric layer along the direction perpendicular to the substrate may be 500 nm, 1000 nm, 1500 nm or 2000 nm, etc.
  • the preparation process of the piezoelectric layer may include PVD, MOCVD (Metal Organic Chemical Vapor Deposition, Metal Organic Chemical Vapor Deposition), patterning, etc.
  • the material of the substrate may include glass, so that the filter unit has low dielectric loss and high resistivity characteristics, which helps to improve the insertion loss performance of the filter unit.
  • the thickness of the substrate may range from 30 to 200 ⁇ m. Specifically, the thickness of the substrate may be 30 ⁇ m, 50 ⁇ m, 80 ⁇ m, 110 ⁇ m, 150 ⁇ m, or 200 ⁇ m, and so on.
  • the above-mentioned modified structure is located in the substrate.
  • the modified structure refers to a structure that is etched at a rate much higher than the unmodified part (ie, the support structure) through the modification process.
  • Modify a part of the glass substrate for example, perform laser-induced etching modification
  • the Si-O molecular bond makes the etching rate of the part of the material that has been treated by the modification process greater than the etching rate of the part of the material that has not been treated by the modification process, that is, the etching rate of the material with modified structure.
  • the shape of the cavity formed between the modified structure and the resonance structure is not specifically limited here.
  • the shape of the cavity can be petal-shaped.
  • the bottom surface of the cavity (the surface on the side of the cavity close to the modified structure) includes at least one arc surface
  • the top surface of the cavity includes a rounded corner structure, which may include a polygon with rounded corners, such as an arc; and a rounded quadrilateral, a rounded pentagon, a circle as shown in Figure 9 Angular triangles and so on.
  • the filter unit provided by the embodiment of the present application includes: a resonant structure; a substrate, which is arranged on one side of the resonant structure.
  • the substrate includes a modified structure and a support structure surrounding the modified structure.
  • a space is formed between the modified structure and the resonant structure. cavity.
  • the filter unit provided by the embodiment of the present application directly forms a resonance structure on the substrate, and the substrate can be processed after the resonance structure is formed, so that a cavity is formed between the modified structure and the resonance structure, thereby avoiding the use of
  • the demanding sacrificial layer processing technology simplifies the preparation process of the cavity in the filter unit and reduces the process requirements of the filter unit, which is very conducive to industrial production.
  • the boundary of the orthographic projection E1 of the resonant structure 2 on the substrate 1 overlaps with the support structure 12 .
  • the surface of the modified structure close to the resonance structure includes at least one arc surface.
  • the boundary of the orthographic projection E1 of the above-mentioned resonant structure on the substrate and the support structure overlaps with the support structure means: as shown in FIG. 5 , the boundary of the orthographic projection E1 of the above-mentioned resonant structure 2 on the substrate 1 all overlaps with the support structure 12; Alternatively, the boundary of the orthographic projection of the above-mentioned resonant structure on the substrate partially overlaps with the support structure, as long as a cavity can be formed between the resonant structure and the modified structure.
  • the surface of the modified structure close to the resonance structure includes at least one arcuate surface, and the number of arcuate surfaces is not specifically limited here.
  • the surface of the modified structure 11 close to the resonant structure 2 includes two arcuate surfaces;
  • Figures 6 to 8 show that the surface of the modified structure 11 close to the resonant structure includes five arcuate surfaces.
  • the top surface of the cavity includes a rounded pentagon.
  • the support structure can well support the resonant structure, while ensuring the resonant structure and the modified structure. While forming a cavity between them, it can also ensure that the filter unit has sufficient mechanical strength.
  • the resonant structure 2 includes at least one through hole 4 , the through hole 4 is connected to the cavity, and the boundary of the orthographic projection E2 of the through hole 4 on the substrate 1 overlaps with the modified structure 11 ;
  • the geometric center of the space occupied by the through hole 4 is collinear with the spherical center 5 of the arc surface. Therefore, the side length and position of the arc surface of the surface of the modified structure close to the resonant structure can be obtained through the position of the through hole.
  • the above-mentioned through holes are configured to allow the etching liquid to flow into the etched substrate to form a modified structure.
  • the above resonant structure includes at least one through hole, and the number of through holes is not specifically limited here.
  • FIG. 5 takes the above-mentioned resonant structure 2 including two through holes 4 as an example.
  • the number and position of the through holes can determine the side length and spherical center of the arc surface of the surface of the modified structure close to the resonant structure. quantity and location, etc.
  • the above-mentioned through hole is connected to the cavity. This is because the corrosive liquid flows into the through hole. The corrosive liquid corrodes the substrate after contact with the substrate, forming a modified structure and a cavity between the modified structure and the resonance structure. At this time, the through hole Must be connected to the cavity.
  • the boundary of the orthographic projection of the above-mentioned through hole on the substrate overlaps with the modified structure means that the boundary of the modified structure is facing the through hole.
  • the boundary of the orthographic projection E2 of the through hole 4 on the substrate 1 completely overlaps with the modified structure 11; or, the boundary of the orthographic projection of the through hole on the substrate partially overlaps with the modified structure, Just ensure that the modified structure can be formed.
  • the arc-shaped spherical center 5 is located at the connection between the through hole 4 and the cavity. Therefore, the spherical center position of the arcuate surface of the surface of the modified structure close to the resonant structure can be obtained through the position of the through hole, and then the side length and position of the arcuate surface can be obtained from the spherical center position.
  • the number of arcuate surfaces is the same as the number of through holes. Therefore, the spherical center position of the arcuate surface of the surface of the modified structure close to the resonant structure can be obtained through the position of the through hole, and then the side length and position of the arcuate surface can be obtained from the spherical center position.
  • the surface of the support structure 12 close to the modified structure 11 includes an annular surface, and the shape of the space enclosed by the annular surface close to the side of the resonant structure 2 is Including polygons with rounded corners, the number of side lengths of a polygon with rounded corners is the same as the number of through holes and the number of arc surfaces. Therefore, the side length, quantity, position, etc. of the arc surface of the surface of the modified structure close to the resonance structure can be obtained through the position of the through hole.
  • the corrosive liquid can corrode the glass substrate to form a cavity.
  • the modified structure has a faster corrosion rate, forming a cavity arc structure, and the areas adjacent to the modified structure and the support structure corrode. The rate is slow and a cavity side structure is formed.
  • the shape of the polygon with rounded corners is not limited here.
  • the shape of the polygon with rounded corners may include a rounded quadrilateral, a rounded pentagon, and a rounded trigonal deformation.
  • Figures 6 to 8 all illustrate the shape of the polygon with rounded corners, including a rounded pentagon, as an example.
  • the radius of curvature of the polygon with rounded corners is not specifically limited here.
  • the radius of curvature of the polygon with rounded corners ranges from 5 to 50 ⁇ m.
  • the radius of curvature of the polygon with rounded corners ranges from 5 ⁇ m, 12 ⁇ m, 25 ⁇ m, 40 ⁇ m, or 50 ⁇ m. etc.
  • the number of side lengths of the above-mentioned polygon with rounded corners is the same as the number of through holes and the number of arc surfaces. This means that the top surface of the cavity formed by injecting the corrosive liquid into any through hole to corrode the substrate forms an edge, and during modification The surface of the side of the structure close to the resonant structure forms an edge such that the number of through holes is the same as the number of side lengths of the polygon with rounded corners, and the number of through holes is also the same as the number of arcuate surfaces.
  • the resonant structure has five through holes
  • the surface of the modified structure close to the resonant structure includes five arc surfaces
  • the polygon with rounded corners includes a pentagon with rounded corners.
  • the filter unit forms a pentagonal cavity.
  • the distance between the connection point L1 of the five arcuate surfaces and the resonant structure is smaller than the distance between the arcuate surface position L2 corresponding to each through hole and the resonant structure.
  • the connection of the five arcuate surfaces is the highest point of the modified structure, and the arcuate surface position corresponding to each through hole is the lowest point of the modified structure, so that the modified structure can form a petal-like shape, that is, a cavity. Form a petal-like shape.
  • the resonant structure has four through holes
  • the surface of the modified structure close to the resonant structure includes four arc surfaces
  • the polygon with rounded corners includes a quadrilateral with rounded corners.
  • the filter unit forms a quadrilateral cavity.
  • the resonant structure has three through holes
  • the surface of the modified structure close to the resonant structure includes three arc surfaces
  • the polygon with rounded corners includes a triangle with rounded corners.
  • the filter unit forms a triangular cavity.
  • the annular surface includes a connected first annular surface and a second annular surface, and the second annular surface is located between the first annular surface and the resonance structure; the first annular surface The part of the surface is in direct contact with the modified structure; the first annular surface and the second annular surface are not coplanar.
  • the angle between the surface of the support structure close to the modified structure and the resonant structure is not perpendicular.
  • first annular surface and the second annular surface are not coplanar means that the side length of the first annular surface and the side length of the second annular surface are not collinear.
  • the space occupied by the first annular surface is smaller than the space occupied by the second annular surface. Therefore, the angle between the second annular surface and the resonant structure is not perpendicular.
  • the range of the angle ⁇ between the second annular surface and the side of the resonant structure close to the substrate includes 80- 88°.
  • the angle ⁇ between the second annular surface and the side of the resonant structure close to the substrate may be 80°, 81°, 83°, 86°, or 88°, etc.
  • the angle between the above-mentioned second annular surface and the side of the resonant structure close to the substrate depends on the etching process. Specifically, when etching with hydrofluoric acid at room temperature, the angle between the second annular surface and the side of the resonant structure close to the substrate
  • the included angle range may include 80-85°, such as: 80°, 83° or 85°, etc.; when using 100-120°C high temperature sodium hydroxide etching, the second annular surface and the resonant structure are close to the substrate
  • the angle range between one side can include 85-88°, for example: 85°, 87° or 88°, etc. In order to obtain a better etching angle closer to 90°, you can choose the 100-120°C high-temperature sodium hydroxide etching process.
  • the etching rate of the material of the modified structure is greater than the etching rate of the material of the supporting structure. Therefore, the filter unit provided by the embodiment of the present application can process the substrate after forming the resonant structure, so that a cavity is formed between the modified structure and the resonant structure, thereby avoiding the use of demanding sacrificial layer processing processes. It simplifies the preparation process of the cavity in the filter unit, reduces the process requirements of the filter unit, and is very conducive to industrial production.
  • Modify a part of the glass substrate for example, perform laser-induced etching modification
  • the interior of the glass can be destroyed through the modification process.
  • the Si-O molecular bond makes the etching rate of the part of the material that has been treated by the modification process greater than the etching rate of the part of the material that has not been treated by the modification process, that is, the etching rate of the material with modified structure. Etch rate greater than the material of the support structure.
  • the filter unit also includes a support layer 3 , which is disposed between the modified structure 11 and the resonance structure 2 ; the through hole 4 also penetrates the support layer 3 and is connected to the cavity.
  • the mechanical strength of the filter unit can be improved through the support layer, the risk of cracks in the resonant structure can be reduced, and the crystal quality of the piezoelectric layer in the resonant structure can be improved.
  • the material of the above support layer may include silicon nitride, aluminum nitride, etc.
  • the thickness range of the above-mentioned support layer along the direction perpendicular to the substrate includes 100-300 nm.
  • the thickness of the above-mentioned support layer along the direction perpendicular to the substrate is 100 nm, 150 nm, 200 nm, 250 nm or 300 nm, etc.
  • the preparation process of the above support layer may include LPCVD (Low Pressure Chemical Vapor Deposition, low pressure chemical vapor deposition), PECVD (Plasma Enhanced Chemical Vapor Deposition, plasma enhanced chemical vapor deposition), PVD, etc.
  • LPCVD Low Pressure Chemical Vapor Deposition, low pressure chemical vapor deposition
  • PECVD Pasma Enhanced Chemical Vapor Deposition, plasma enhanced chemical vapor deposition
  • PVD etc.
  • the silicon nitride support layer can be deposited by LPCVD or PECVD, or the aluminum nitride support layer can be deposited by PVD.
  • the material of the modified structure includes glass. Therefore, compared with the single crystal silicon substrate in the related art, the glass substrate provided by the embodiment of the present application has lower dielectric loss and high resistivity characteristics, which is more conducive to improving the insertion loss performance of the filter unit.
  • the type of glass mentioned above may include low dielectric loss glass, such as fused silica glass, alkali-free borosilicate glass, etc.
  • Embodiments of the present application also provide an electronic device, including at least three filter units as described above, at least two of the at least three filter units being connected in series, and with other filter units than the series connected filter units. Filter units are connected in parallel.
  • the number of the above-mentioned series-connected filter units and the number of parallel-connected filter units which are specifically determined by the volume and type of the filter.
  • the number range of the series-connected filter units and the number range of the parallel-connected filter units may both include 3-5.
  • Figure 13 shows an example of a filter including seven filter units, four of which are connected in series, and the series-connected filter units are connected in parallel with three filter units.
  • the filter includes Unit B1, filter unit B2, filter unit B3, filter unit B4, filter unit B5, filter unit B6 and filter unit B7, of which four filter units are connected in series, namely filter unit B1, filter unit B2, the filter unit B3 and the filter unit B4 are connected in series, and the series-connected filter unit is connected in parallel with the three filter units, that is, in parallel with the filter unit B5, the filter unit B6, and the filter unit B7.
  • the above-mentioned electronic equipment is suitable for a variety of circuit scenarios based on glass-based air gap types, and is not specifically limited here.
  • the electronic equipment provided by the embodiments of the present application greatly simplifies the process preparation process, reduces the difficulty of the process, and is simple and easy to implement.
  • the embodiment of the present application further provides a method for manufacturing the above filter unit.
  • the method includes:
  • the material of the substrate may include glass, so that the filter unit has low dielectric loss and high resistivity characteristics, which helps to improve the insertion loss performance of the filter unit.
  • the thickness of the substrate may range from 30 to 200 ⁇ m. Specifically, the thickness of the substrate may be 30 ⁇ m, 50 ⁇ m, 80 ⁇ m, 110 ⁇ m, 150 ⁇ m, or 200 ⁇ m, and so on.
  • the above resonant structure may include a first electrode 21 , a piezoelectric layer 22 and a second electrode 23 that are stacked in sequence.
  • a voltage such as AC
  • the piezoelectric effect converts electrical energy into mechanical energy, causing the piezoelectric layer 22 to undergo mechanical deformation, and then excites body acoustic waves in the piezoelectric layer 22.
  • the body acoustic waves are formed between the modified structure 11 and the resonant structure 2
  • the cavity vibrates and propagates.
  • the above S1, forming the substrate includes:
  • the substrate 1 is modified to form a modified part 13 and a support structure 12 ; the support structure 12 surrounds the modified part 13 .
  • the above-mentioned process of modifying the substrate may include an etching process, such as a laser-induced etching process. At this time, only a part of the substrate can be modified by laser-induced etching. As shown in Figure 10, the middle part of the substrate is modified to form a modified part 13, and the other unmodified parts of the substrate constitute the support structure. 12.
  • the laser-induced etching process can destroy the Si-O molecular bonds inside the glass, and then when the substrate is wet etched, the wet etching rate of the modified part material is much higher It affects the wet etching rate of the support structure, but does not affect the flatness of the glass substrate surface, so that a cavity can be formed between the glass substrate and the resonant structure by etching part of the glass substrate.
  • the embodiments of the present application modify the substrate through, for example, laser-induced etching technology, which can very effectively simplify the process preparation process and reduce the difficulty of the process.
  • the above S2, forming a resonant structure on one side of the substrate; having a cavity between the resonant structure and the substrate includes:
  • At least one through hole 4 is formed on the resonant structure 2.
  • the above-mentioned preparation process of forming at least one through hole on the resonant structure is not specifically limited here.
  • at least one through hole may be formed on the resonant structure through a dry etching process.
  • FIG. 5 takes the above-mentioned resonant structure 2 including two through holes 4 as an example.
  • the number and position of the through holes can determine the side length and spherical center of the arc surface of the surface of the modified structure close to the resonant structure. quantity and location, etc.
  • the above-mentioned corrosive liquid may include hydrofluoric acid, potassium hydroxide corrosion, etc.
  • the corrosive liquid can corrode the glass substrate to form a cavity.
  • the modified structure has a faster corrosion rate, forming a cavity arc structure, and the areas adjacent to the modified structure and the support structure corrode. The rate is slow and a cavity side structure is formed.
  • the substrate is modified to form a modified part and a support structure; after the support structure surrounds the modified part, and before at least one through hole is formed on the resonant structure in S21, the method also include:
  • the support layer 3 is formed on the modified part 13 and the support structure 12 .
  • the preparation process of the above support layer is not specifically limited here.
  • the preparation process of the above support layer may include LPCVD, PECVD, PVD, etc.
  • the silicon nitride support layer can be deposited by LPCVD or PECVD, or the aluminum nitride support layer can be deposited by PVD.
  • the material of the above support layer may include silicon nitride, aluminum nitride, etc.
  • the thickness range of the above-mentioned support layer along the direction perpendicular to the substrate includes 100-300 nm. Specifically, the thickness of the above-mentioned support layer along the direction perpendicular to the substrate is 100 nm, 150 nm, 200 nm, 250 nm or 300 nm, etc.
  • a resonant structure 2 is formed on the support layer 3 .
  • the resonant structure 2 includes a first electrode 21 , a piezoelectric layer 22 and a second electrode 23 that are stacked in sequence.
  • the preparation process of the above resonance structure is not specifically limited here.
  • the preparation process of the first electrode and the second electrode may include PVD and patterning.
  • the preparation process of the piezoelectric layer may include PVD, MOCVD, patterning, etc.
  • molybdenum is deposited on the support layer 3 to form the first electrode 21 .
  • molybdenum is deposited on the piezoelectric layer 22 to form the second electrode 23 .

Abstract

本申请提供了一种滤波器单元及其制备方法、电子设备，涉及射频微机电系统技术领域，该滤波器单元包括：谐振结构；衬底，设置在所述谐振结构的一侧，所述衬底包括改性结构和围绕所述改性结构的支撑结构，所述改性结构与所述谐振结构之间形成空腔。本申请提供的滤波器单元通过改性结构与谐振结构之间形成空腔，从而可以大大简化工艺制备流程，降低工艺制程难度。

Description

一种滤波器单元及其制备方法、电子设备 技术领域
本申请涉及射频微机电系统技术领域，尤其涉及一种滤波器单元及其制备方法、电子设备。
背景技术
滤波器作为重要的射频元件在通信领域发挥了举足轻重的作用。随着科技的发展，薄膜体声波谐振器(FBAR)技术成为了射频滤波器的主流技术，其中，FBAR包括空气隙型薄膜体声波谐振器。
目前空气隙型FBAR常通过沉积牺牲层的方法制得。但是，传统的牺牲层的处理工艺要求非常严苛，导致空气隙型FBAR的制备工艺十分复杂，不利于工业化生产。
发明内容
本申请的实施例采用如下技术方案：
一方面，本申请的实施例提供了一种滤波器单元，包括：
谐振结构；
衬底，设置在所述谐振结构的一侧，所述衬底包括改性结构和围绕所述改性结构的支撑结构，所述改性结构与所述谐振结构之间形成空腔。
可选地，所述谐振结构在所述衬底上的正投影的边界与所述支撑结构有交叠；
所述改性结构靠近所述谐振结构一侧的表面包括至少一个弧面。
可选地，所述谐振结构包括至少一个通孔，所述通孔与所述空腔连通，所述通孔在所述衬底上的正投影的边界与所述改性结构有交叠；所述通孔所占空间的几何中心与所述弧面的球心共线。
可选地，所述弧面的球心位于所述通孔与所述空腔的连通处。
可选地，所述弧面的数量与所述通孔的数量相同。
可选地，所述支撑结构靠近所述改性结构一侧的表面包括环形面，所述环形面靠近所述谐振结构一侧的边所围成的空间的形状包括具有圆角的多边形，具有圆角的所述多边形的边长数量与所述通孔的数量和所述弧面的数量均相同。
可选地，所述谐振结构具有五个通孔，所述改性结构靠近所述谐振结构一侧的表面包括五个弧面，具有圆角的所述多边形包括具有圆角的 五边形。
可选地，五个所述弧面的连接处与所述谐振结构之间的距离小于各所述通孔对应的所述弧面位置与所述谐振结构之间的距离。
可选地，所述谐振结构具有四个通孔，所述改性结构靠近所述谐振结构一侧的表面包括四个弧面，具有圆角的所述多边形包括具有圆角的四边形；
或者，所述谐振结构具有三个通孔，所述改性结构靠近所述谐振结构一侧的表面包括三个弧面，具有圆角的所述多边形包括具有圆角的三角形。
可选地，所述环形面包括相连的第一环形面和第二环形面，所述第二环形面位于所述第一环形面与所述谐振结构之间；所述第一环形面的部分与所述改性结构直接接触；所述第一环形面与所述第二环形面不共面。
可选地，所述第一环形面所占的空间小于所述第二环形面所占的空间。
可选地，所述第二环形面与所述谐振结构靠近所述衬底的一侧之间的夹角范围包括80-88°。
可选地，所述改性结构的材料的刻蚀速率大于所述支撑结构的材料的刻蚀速率。
可选地，所述滤波器单元还包括支撑层，所述支撑层设置在所述改性结构和所述谐振结构之间；
所述通孔还贯穿所述支撑层、且与所述空腔连通。
可选地，所述改性结构的材料包括玻璃。
另一方面，本申请的实施例提供了一种电子设备，包括上述的至少三个滤波器单元，至少三个所述滤波器单元中的至少两个滤波器单元串联、且与除串联的所述滤波器单元以外的其它所述滤波器单元并联。
再一方面，本申请的实施例提供了一种上述的滤波器单元的制备方法，所述方法包括：
形成衬底；
在所述衬底的一侧形成谐振结构；所述谐振结构与所述衬底之间具有空腔。
可选地，所述形成衬底包括：
提供衬底；
对所述衬底进行改性，形成改性部和支撑结构；所述支撑结构围绕所述改性部。
可选地，所述在所述衬底的一侧形成谐振结构；所述谐振结构与所述衬底之间具有空腔包括：
在所述谐振结构上形成至少一个通孔；
通过所述通孔注入腐蚀液腐蚀所述改性部，形成改性结构、以及所述改性结构与所述谐振结构之间的空腔。
上述说明仅是本申请技术方案的概述，为了能够更清楚了解本申请的技术手段，而可依照说明书的内容予以实施，并且为了让本申请的上述和其它目的、特征和优点能够更明显易懂，以下特举本申请的具体实施方式。
附图说明
为了更清楚地说明本申请实施例或相关技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其它的附图。
图1至图4为本申请实施例提供的一种相关技术中的空气隙型FBAR的制备过程；
图5为本申请实施例提供的一种滤波器单元的结构示意图；
图6为本申请实施例提供的一种滤波器单元中改性结构的俯视图；
图7为本申请实施例提供的一种滤波器单元中衬底的立体图；
图8为本申请实施例提供的一种滤波器单元中衬底的截面图；
图9为本申请实施例提供的一种滤波器单元中改性结构靠近谐振结构一侧的表面的多种形状图；
图10至图12为本申请实施例提供的一种滤波器单元的制备过程；
图13为本申请实施例提供的一种电子设备的结构示意图。
具体实施例
为使本申请实施例的目的、技术方案和优点更加清楚，下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
在图中，为了清晰，可能夸大了区域和层的厚度。在图中相同的附图标记表示相同或类似的结构，因而将省略它们的详细描述。此外，附图仅为本申请的示意性图解，并非一定是按比例绘制。
在本申请的实施例中，除非另有说明，“多个”的含义是两个或两个以上；术语“上”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的结构或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。
除非上下文另有要求，否则，在整个说明书和权利要求书中，术语“包括”被解释为开放、包含的意思，即为“包含，但不限于”。在说明书的描述中，术语“一个实施例”、“一些实施例”、“示例性实施例”、“示例”、“特定示例”或“一些示例”等旨在表明与该实施例或示例相关的特定特征、结构、材料或特性包括在本申请的至少一个实施例或示例中。上述术语的示意性表示不一定是指同一实施例或示例。此外，所述的特定特征、结构、材料或特点可以以任何适当方式包括在任何一个或多个实施例或示例中。
在本申请的实施例中，采用“第一”、“第二”等字样对功能和作用基本相同的相同项或相似项进行区分，仅为了清楚描述本申请实施例的技术方案，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。
随着现代无线通信技术向高频、高速等方向发展，对射频通信常用的前端滤波器提出了更高的要求。FBAR作为一种新型滤波器，在5G通信中具有广泛的应用。根据器件结构的不同，FBAR可以分为背刻型和空气隙型两大类。背刻型FBAR的结构稳定性较差、良品率低，相比于背刻型FBAR，空气隙型FBAR的机械可靠性更佳、应用更为广泛。
目前的空气隙型FBAR包括衬底和设置在衬底上的电极-压电薄膜-电极结构。当在两个电极上施加电压时，压电效应使得电能转化为机械能，从而使得压电薄膜发生机械形变，进而在压电薄膜体内激励出体声波。为了减少 声波的损失，尽量要使声波能够形成全反射，由于空气的声阻抗可以认为近似为零，因此制作空气隙型FBAR时要使两个电极表面均与空气接触。空气隙型FBAR中，远离衬底的一个电极必然与空气接触，而靠近衬底的一个电极由于生长在衬底上，需要使用刻蚀的方法除去该电极处的至少部分衬底材料，使该电极既能够与空气接触、又可以保证足够的机械强度，即制成了空气隙型薄膜体声波谐振器。
主流的空气隙型薄膜体声波谐振器的制备方法如图1至图4所示。首先，参考图1所示，在单晶硅衬底101表面刻蚀形成凹槽102；接着，参考图2所示，在凹槽处沉积氧化硅或PSG(掺磷氧化硅)，形成牺牲层103；然后，参考图3所示，通过CMP(Chemical Mechanical Polishing，化学机械抛光制程)工艺研磨抛光多余牺牲层103材料，形成平坦的底面结构；最后，参考图4所示，在具有牺牲层的衬底上依次层叠形成支撑层3和谐振结构2，再在谐振结构3上形成通孔，通过通孔使得腐蚀液与牺牲层接触后腐蚀牺牲层，以去除牺牲层后，形成如图4所示的空腔，即得到相关技术中的空气隙型薄膜体声波谐振器。
但是，为了使得谐振结构中的膜层获得较好的结晶膜层质量，对上述CMP工艺过程处理过的膜层表面的平整度要求非常严苛，例如需要使得膜层表面的粗糙度小于0.5nm、CMP碟形效应所产生的凹陷小于50nm等等，这就必然使得空气隙型薄膜体声波谐振器的制备工艺复杂，不利于工业化生产。
基于上述，本申请的实施例提供了一种滤波器单元，参考图5所示，该滤波器单元包括：谐振结构2。
衬底1，设置在谐振结构2的一侧，衬底1包括改性结构11和围绕改性结构11的支撑结构12，改性结构11与谐振结构2之间形成空腔。
对于上述谐振结构的具体结构不做限定。示例的，参考图5所示，上述谐振结构可以包括依次层叠设置的第一电极21、压电层22和第二电极23，当在第一电极21和第二电极23上施加电压(例如交流电压)时，压电效应使得电能转化为机械能，从而使得压电层22发生机械形变，进而在压电层22体内激励出体声波，该体声波在改性结构11与谐振结构2之间形成的空腔处振动，从而进行传播。
这里对于上述第一电极和第二电极的材料、厚度、制备工艺等均不做具体限定。示例的，上述第一电极和第二电极的材料可以均包括高声阻材料， 例如：钼、钨等，用于为压电层施加电信号激励。示例的，上述第一电极和第二电极沿垂直于衬底方向的厚度范围均可以包括200-600nm，具体的，上述第一电极和第二电极沿垂直于衬底方向的厚度均可以为200nm、400nm、500nm、600nm等等。示例的，上述第一电极和第二电极的制备工艺可以均包括PVD(Physical Vapor Deposition，物理气相沉积)及图形化等。
这里对于上述压电层的材料、厚度、制备工艺等均不做具体限定。示例的，上述压电层的材料可以包括氮化铝、氮化铝钪等，用于接收两电极产生的电信号激励，形成机械谐振。示例的，上述压电层沿垂直于衬底方向的厚度范围可以包括500-2000nm，具体的，上述压电层沿垂直于衬底方向的厚度可以为500nm、1000nm、1500nm或者2000nm等等。示例的，上述压电层的制备工艺可以包括PVD、MOCVD(Metal Organic Chemical Vapor Deposition，金属有机化学气相沉积)及图形化等。
这里对于上述衬底的材料、厚度等均不做具体限定。示例的，上述衬底的材料可以包括玻璃，以使得滤波器单元具有低介电损耗和高电阻率特性，有助于提升滤波器单元的插入损耗性能。示例的，上述衬底的厚度范围可以包括30-200μm，具体的，上述衬底的厚度可以为30μm、50μm、80μm、110μm、150μm或者200μm等等。
上述改性结构位于衬底内，该改性结构是指通过改性工艺使得对其进行刻蚀的速率远高于未改性部分(即支撑结构)进行刻蚀的速率的结构。现以衬底的材料为玻璃为例具体说明改性结构和支撑结构的形成原理：对玻璃衬底的一部分进行改性(例如进行激光诱导刻蚀改性)，通过改性工艺可以破坏玻璃内部的Si-O分子键，使得经过改性工艺处理的那部分材料的刻蚀速率大于衬底上未经过改性工艺处理部分的材料的刻蚀速率，也即改性结构的材料的刻蚀速率大于支撑结构的材料的刻蚀速率。
这里对于上述改性结构和谐振结构之间形成的空腔的形状不做具体限定。示例的，参考图6至图8所示，上述空腔的形状可以呈花瓣状，此时空腔的底面(空腔靠近改性结构一侧的表面)包括至少一个弧面，空腔的顶面(空腔靠近谐振结构一侧的表面)包括圆角结构，该圆角结构可以包括具有圆角的多边形，例如圆弧形；以及图9所示的圆角四边形、圆角五边形、圆角三边形等等。
本申请实施例提供的滤波器单元包括：谐振结构；衬底，设置在谐振结构的一侧，衬底包括改性结构和围绕改性结构的支撑结构，改性结构与谐振 结构之间形成空腔。这样，相比于传统的通过先在硅衬底上形成凹槽，再在凹槽内形成并去除牺牲层后形成空腔，本申请实施例提供的滤波器单元省略了牺牲层，也就省去了CMP工艺，从而大大简化了工艺制备流程，降低了工艺制程难度。那么，本申请实施例提供的滤波器单元直接在衬底上形成谐振结构，可以在形成谐振结构后再对衬底进行处理，以使得改性结构与谐振结构之间形成空腔，从而避免使用要求严苛的牺牲层处理工艺，简化了滤波器单元中空腔的制备工艺，降低了滤波器单元的工艺制程要求，十分有利于工业化生产。
可选地，参考图5所示，谐振结构2在衬底1上的正投影E1的边界与支撑结构12有交叠。
参考图6至图8所示，改性结构靠近谐振结构一侧的表面包括至少一个弧面。
上述谐振结构在衬底上的正投影的边界与支撑结构有交叠是指：参考图5所示，上述谐振结构2在衬底1上的正投影E1的边界全部与支撑结构12交叠；或者，上述谐振结构在衬底上的正投影的边界与支撑结构部分交叠，只要保证谐振结构与改性结构之间能够形成空腔即可。
上述改性结构靠近谐振结构一侧的表面包括至少一个弧面，这里对于弧面的数量不做具体限定。示例的，图5以改性结构11靠近谐振结构2一侧的表面包括两个弧面为例进行绘示；图6至图8以改性结构靠近谐振结构一侧的表面包括五个弧面为例进行绘示，此时空腔的顶面包括圆角五边形。
本申请实施例提供的滤波器单元中，由于谐振结构在衬底上的正投影的边界与支撑结构有交叠，使得支撑结构可以很好的支撑谐振结构，在保证谐振结构与改性结构之间形成空腔的同时，又可以保证滤波器单元具有足够的机械强度。
可选地，参考图5所示，谐振结构2包括至少一个通孔4，通孔4与空腔连通，通孔4在衬底1上的正投影E2的边界与改性结构11有交叠；通孔4所占空间的几何中心与弧面的球心5共线。从而能够通过通孔的位置得到改性结构靠近谐振结构一侧的表面的弧面的边长及其位置等。
上述通孔被配置为使得腐蚀液流入腐蚀衬底形成改性结构。上述谐振结构包括至少一个通孔，这里对于通孔的数量不做具体限定。示例的，图5以上述谐振结构2包括两个通孔4为例进行绘示，通孔的数量及其位置可以决定改性结构靠近谐振结构一侧的表面的弧面的边长、球心的数量及其位置等。
上述通孔与空腔连通，这是由于通孔内流入腐蚀液，腐蚀液与衬底接触后腐蚀衬底，形成改性结构以及改性结构与谐振结构之间的空腔，此时通孔必然与空腔连通。
上述通孔在衬底上的正投影的边界与改性结构有交叠是指：改性结构的边界正对于通孔。参考图5所示，通孔4在衬底1上的正投影E2的边界全部与改性结构11交叠；或者，通孔在衬底上的正投影的边界与改性结构部分交叠，只要保证可以形成改性结构即可。
可选地，参考图5所示，弧面的球心5位于通孔4与空腔的连通处。从而能够通过通孔的位置得到改性结构靠近谐振结构一侧的表面的弧面的球心位置，进而由该球心位置得到弧面的边长及其位置等。
可选地，参考图5、图6-图8所示，弧面的数量与通孔的数量相同。从而能够通过通孔的位置得到改性结构靠近谐振结构一侧的表面的弧面的球心位置，进而由该球心位置得到弧面的边长及其位置等。
可选地，由于刻蚀工艺的影响，参考图5所示，支撑结构12靠近改性结构11一侧的表面包括环形面，环形面靠近谐振结构2一侧的边所围成的空间的形状包括具有圆角的多边形，具有圆角的多边形的边长数量与通孔的数量和弧面的数量均相同。从而能够通过通孔的位置得到改性结构靠近谐振结构一侧的表面的弧面的边长、数量、位置等。
以衬底材料为玻璃为例进行说明，腐蚀液可以腐蚀玻璃衬底形成空腔，其中，改性结构的腐蚀速率较快，形成空腔弧面结构，改性结构与支撑结构相邻区域腐蚀速率较慢，形成空腔侧面结构。
这里对于上述具有圆角的多边形的具体形状不做限定。示例的，参考图9所示，上述具有圆角的多边形的形状可以包括圆角四边形、圆角五边形和圆角三变形。图6至图8均以上述具有圆角的多边形的形状包括圆角五边形为例进行绘示。
这里对于上述具有圆角的多边形的曲率半径不做具体限定。示例的，受玻璃激光诱导刻蚀工艺限制，上述具有圆角的多边形的曲率半径范围包括5-50μm，具体的，上述具有圆角的多边形的曲率半径范围为5μm、12μm、25μm、40μm或者50μm等等。
上述具有圆角的多边形的边长数量与通孔的数量和弧面的数量均相同是指：在任一通孔内注入腐蚀液腐蚀衬底形成的空腔的顶面形成一条边、且在改性结构靠近谐振结构一侧的表面形成一条边，以使得通孔的数量与具有 圆角的多边形的边长数量相同、且通孔的数量与弧面的数量也相同。
可选地，参考图6至图8所示，谐振结构具有五个通孔，改性结构靠近谐振结构一侧的表面包括五个弧面，具有圆角的多边形包括具有圆角的五边形。从而使得滤波器单元形成五边形的空腔。
可选地，参考图7和图8所示，五个弧面的连接处L1与谐振结构之间的距离小于各通孔对应的弧面位置L2与谐振结构之间的距离。此时五个弧面的连接处为改性结构的最高点，各通孔对应的弧面位置均为改性结构的最低点，从而使得改性结构能够形成花瓣状的形状，也即空腔形成花瓣状的形状。
可选地，参考图9所示，谐振结构具有四个通孔，改性结构靠近谐振结构一侧的表面包括四个弧面，具有圆角的多边形包括具有圆角的四边形。从而使得滤波器单元形成四边形的空腔。
或者，参考图9所示，谐振结构具有三个通孔，改性结构靠近谐振结构一侧的表面包括三个弧面，具有圆角的多边形包括具有圆角的三角形。从而使得滤波器单元形成三边形的空腔。
可选地，由于刻蚀工艺的影响，参考图5所示，环形面包括相连的第一环形面和第二环形面，第二环形面位于第一环形面与谐振结构之间；第一环形面的部分与改性结构直接接触；第一环形面与第二环形面不共面。从而使得支撑结构靠近改性结构一侧的表面与谐振结构之间的夹角不垂直。
上述第一环形面与第二环形面不共面是指：第一环形面的边长与第二环形面的边长不共线。
可选地，由于刻蚀工艺的影响，参考图5所示，第一环形面所占的空间小于第二环形面所占的空间。从而使得第二环形面与谐振结构之间的夹角不垂直。
可选地，由于刻蚀工艺的影响，例如受玻璃激光诱导刻蚀工艺限制，参考图5所示，第二环形面与谐振结构靠近衬底的一侧之间的夹角θ范围包括80-88°。
这里对于上述第二环形面与谐振结构靠近衬底的一侧之间的夹角θ的范围不做具体限定。示例的，上述第二环形面与谐振结构靠近衬底的一侧之间的夹角θ可以为80°、81°、83°、86°或者88°等等。
上述第二环形面与谐振结构靠近衬底的一侧之间的夹角取决于刻蚀工艺，具体的，当采用常温氢氟酸腐蚀时，第二环形面与谐振结构靠近衬底的 一侧之间的夹角范围可以包括80-85°，例如：80°、83°或者85°等等；当采用100-120℃高温氢氧化钠腐蚀时，第二环形面与谐振结构靠近衬底的一侧之间的夹角范围可以包括85-88°，例如：85°、87°或者88°等等。为了获得更好的、更接近于90°的刻蚀角度，可以选择100-120℃高温氢氧化钠腐蚀工艺。
可选地，改性结构的材料的刻蚀速率大于支撑结构的材料的刻蚀速率。从而使得本申请实施例提供的滤波器单元可以在形成谐振结构后再对衬底进行处理，以使得改性结构与谐振结构之间形成空腔，从而避免使用要求严苛的牺牲层处理工艺，简化了滤波器单元中空腔的制备工艺，降低了滤波器单元的工艺制程要求，十分有利于工业化生产。
现以衬底的材料为玻璃为例具体说明改性结构和支撑结构的形成原理：对玻璃衬底的一部分进行改性(例如进行激光诱导刻蚀改性)，通过改性工艺可以破坏玻璃内部的Si-O分子键，使得经过改性工艺处理的那部分材料的刻蚀速率大于衬底上未经过改性工艺处理部分的材料的刻蚀速率，也即改性结构的材料的刻蚀速率大于支撑结构的材料的刻蚀速率。
可选地，参考图5所示，滤波器单元还包括支撑层3，支撑层3设置在改性结构11和谐振结构2之间；通孔4还贯穿支撑层3、且与空腔连通。从而可以通过支撑层提升滤波器单元的机械强度，降低谐振结构的裂片风险，提高谐振结构中压电层的结晶质量。
这里对于上述支撑层的材料、厚度、制备工艺等均不做具体限定。示例的，上述支撑层的材料可以包括氮化硅、氮化铝等。
示例的，上述支撑层沿垂直于衬底方向的厚度范围包括100-300nm，具体的，上述支撑层沿垂直于衬底方向的厚度为100nm、150nm、200nm、250nm或者300nm等等。
示例的，上述支撑层的制备工艺可以包括LPCVD(Low Pressure Chemical Vapor Deposition，低压力化学气相沉积)、PECVD(Plasma Enhanced Chemical Vapor Deposition，等离子体增强化学的气相沉积)、PVD等。其中可以通过LPCVD或PECVD沉积氮化硅支撑层，或者，采用PVD沉积氮化铝支撑层。
可选地，改性结构的材料包括玻璃。从而与相关技术中的单晶硅衬底相比，本申请实施例提供的玻璃衬底具有更低的介电损耗和高电阻率特性，更有助于提升滤波器单元的插入损耗性能。
这里对于上述玻璃的具体类型不做限定。示例的，上述玻璃的类型可以包括低介电损耗玻璃，例如：熔融石英玻璃、无碱硼硅玻璃等。
本申请的实施例还提供了一种电子设备，包括上述的至少三个滤波器单元，至少三个滤波器单元中的至少两个滤波器单元串联、且与除串联的滤波器单元以外的其它滤波器单元并联。
这里对于上述串联的滤波器单元的数量以及并联的滤波器单元的数量均不做具体限定，具体以滤波器的体积、类型等进行确定。为了实现较好的滤波效果，同时避免制作工艺复杂，示例的，上述串联的滤波器单元的数量范围和并联的滤波器单元的数量范围可以均包括3-5个。图13以滤波器包括七个滤波器单元，其中四个滤波器单元串联、且串联的滤波器单元与三个滤波器单元并联为例进行绘示，参考图13所示，滤波器包括滤波器单元B1、滤波器单元B2、滤波器单元B3、滤波器单元B4、滤波器单元B5、滤波器单元B6和滤波器单元B7，其中四个滤波器单元串联，即滤波器单元B1、滤波器单元B2、滤波器单元B3和滤波器单元B4串联，串联的滤波器单元与三个滤波器单元并联，即与滤波器单元B5、滤波器单元B6、滤波器单元B7分别并联。
上述电子设备适用于基于玻璃基空气隙型的多种电路场景，这里不做具体限定。
本申请实施例提供的电子设备大大简化了工艺制备流程，降低了工艺制程难度，简单易实现。
本申请的实施例再提供了一种如上述滤波器单元的制备方法。
该方法包括：
S1、形成衬底。
这里对于上述衬底的材料、厚度等均不做具体限定。示例的，上述衬底的材料可以包括玻璃，以使得滤波器单元具有低介电损耗和高电阻率特性，有助于提升滤波器单元的插入损耗性能。示例的，上述衬底的厚度范围可以包括30-200μm，具体的，上述衬底的厚度可以为30μm、50μm、80μm、110μm、150μm或者200μm等等。
S2、在衬底的一侧形成谐振结构；谐振结构与衬底之间具有空腔。
对于上述谐振结构的具体结构不做限定。示例的，参考图5所示，上述谐振结构可以包括依次层叠设置的第一电极21、压电层22和第二电极23，当在第一电极21和第二电极23上施加电压(例如交流电压)时，压电效应 使得电能转化为机械能，从而使得压电层22发生机械形变，进而在压电层22体内激励出体声波，该体声波在改性结构11与谐振结构2之间形成的空腔处振动，从而进行传播。
本申请实施例提供的滤波器单元的制备方法相比于传统的通过先在硅衬底上形成凹槽，再在凹槽内形成并去除牺牲层后形成空腔的制备方法，省略了形成牺牲层、去除牺牲层等步骤，也就省去了CMP工艺，从而大大简化了工艺制备流程，降低了工艺制程难度。
可选地，上述S1、形成衬底包括：
S11、提供衬底。
S12、参考图10所示，对衬底1进行改性，形成改性部13和支撑结构12；支撑结构12围绕改性部13。
这里对于上述对衬底进行改性的工艺不做具体限定。示例的，上述对衬底进行改性的工艺可以包括刻蚀工艺，例如：激光诱导刻蚀工艺。此时可以仅对衬底的一部分进行激光诱导刻蚀改性，如图10所示的对衬底中间的部分区域进行改性形成改性部13，衬底的其它未改性部分构成支撑结构12。
当衬底的材料为玻璃时，激光诱导刻蚀工艺可以破坏玻璃内部的Si-O分子键，进而在对衬底进行湿法刻蚀时，改性部的材料的湿法刻蚀速率远高于支撑结构的湿法刻蚀速率，但不会影响玻璃衬底表面的平整度，从而能够通过腐蚀部分玻璃衬底使得玻璃衬底与谐振结构之间形成空腔。
本申请实施例通过例如激光诱导刻蚀技术对衬底进行改性，能够非常有效的简化工艺制备流程，降低工艺制程难度。
可选地，上述S2、在衬底的一侧形成谐振结构；谐振结构与衬底之间具有空腔包括：
S21、参考图12所示，在谐振结构2上形成至少一个通孔4。
S22、通过通孔注入腐蚀液腐蚀改性部，形成改性结构、以及改性结构与谐振结构之间的空腔。
这里对于上述在谐振结构上形成至少一个通孔的制备工艺不做具体限定。示例的，可以通过干法刻蚀工艺在谐振结构上形成至少一个通孔。
这里对于上述通孔的数量不做具体限定。示例的，图5以上述谐振结构2包括两个通孔4为例进行绘示，通孔的数量及其位置可以决定改性结构靠近谐振结构一侧的表面的弧面的边长、球心的数量及其位置等。
这里对于上述腐蚀液不做具体限定。示例的，上述腐蚀液可以包括氢氟 酸、氢氧化钾腐蚀等等。以衬底材料为玻璃为例进行说明，腐蚀液可以腐蚀玻璃衬底形成空腔，其中，改性结构的腐蚀速率较快，形成空腔弧面结构，改性结构与支撑结构相邻区域腐蚀速率较慢，形成空腔侧面结构。
需要说明的是，在S12、对衬底进行改性，形成改性部和支撑结构；支撑结构围绕改性部之后，以及在S21、在谐振结构上形成至少一个通孔之前，所述方法还包括：
S13、参考图11所示，在改性部13和支撑结构12上形成支撑层3。
这里对于上述支撑层的制备工艺不做具体限定。示例的，上述支撑层的制备工艺可以包括LPCVD、PECVD、PVD等。其中可以通过LPCVD或PECVD沉积氮化硅支撑层，或者，采用PVD沉积氮化铝支撑层。
这里对于上述支撑层的材料、厚度等均不做具体限定。示例的，上述支撑层的材料可以包括氮化硅、氮化铝等。示例的，上述支撑层沿垂直于衬底方向的厚度范围包括100-300nm，具体的，上述支撑层沿垂直于衬底方向的厚度为100nm、150nm、200nm、250nm或者300nm等等。
S14、参考图11所示，在支撑层3上形成谐振结构2，谐振结构2包括依次层叠设置的第一电极21、压电层22和第二电极23。
这里对于上述谐振结构的制备工艺不做具体限定。示例的，上述第一电极和第二电极的制备工艺可以均包括PVD及图形化等。示例的，上述压电层的制备工艺可以包括PVD、MOCVD及图形化等。
下面提供一种具体的滤波器单元的制备方法。
S31、参考图10所示，在玻璃衬底1表面采用激光诱导刻蚀，形成改性部13和支撑结构12。
S32、参考图11所示，在改性部13和支撑结构12上沉积氮化硅，形成支撑层3。
S33、参考图11所示，在支撑层3上沉积钼，形成第一电极21。
S34、参考图11所示，在第一电极21上沉积氮化铝，形成压电层22。
S35、参考图11所示，在压电层22上沉积钼，形成第二电极23。
S36、参考图12所示，依次在第二电极23、压电层22和第一电极21上刻蚀，形成通孔4。
S37、在通孔4内流入氢氟酸腐蚀玻璃衬底，形成空腔。
本申请实施例中关于滤波器单元的结构说明可以参考上述实施例，这里不再赘述。
在此处所提供的说明书中，说明了大量具体细节。然而，能够理解，本申请的实施例可以在没有这些具体细节的情况下被实践。在一些实例中，并未详细示出公知的方法、结构和技术，以便不模糊对本说明书的理解。
最后应说明的是：以上实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的精神和范围。

Claims (19)

  1. 一种滤波器单元，其中，包括：
    谐振结构；
    衬底，设置在所述谐振结构的一侧，所述衬底包括改性结构和围绕所述改性结构的支撑结构，所述改性结构与所述谐振结构之间形成空腔。
  2. 根据权利要求1所述的滤波器单元，其中，所述谐振结构在所述衬底上的正投影的边界与所述支撑结构有交叠；
    所述改性结构靠近所述谐振结构一侧的表面包括至少一个弧面。
  3. 根据权利要求2所述的滤波器单元，其中，所述谐振结构包括至少一个通孔，所述通孔与所述空腔连通，所述通孔在所述衬底上的正投影的边界与所述改性结构有交叠；所述通孔所占空间的几何中心与所述弧面的球心共线。
  4. 根据权利要求3所述的滤波器单元，其中，所述弧面的球心位于所述通孔与所述空腔的连通处。
  5. 根据权利要求3所述的滤波器单元，其中，所述弧面的数量与所述通孔的数量相同。
  6. 根据权利要求3所述的滤波器单元，其中，所述支撑结构靠近所述改性结构一侧的表面包括环形面，所述环形面靠近所述谐振结构一侧的边所围成的空间的形状包括具有圆角的多边形，具有圆角的所述多边形的边长数量与所述通孔的数量和所述弧面的数量均相同。
  7. 根据权利要求6所述的滤波器单元，其中，所述谐振结构具有五个通孔，所述改性结构靠近所述谐振结构一侧的表面包括五个弧面，具有圆角的所述多边形包括具有圆角的五边形。
  8. 根据权利要求7所述的滤波器单元，其中，五个所述弧面的连接处与所述谐振结构之间的距离小于各所述通孔对应的所述弧面位置与所述谐振结构之间的距离。
  9. 根据权利要求6所述的滤波器单元，其中，所述谐振结构具有四个通孔，所述改性结构靠近所述谐振结构一侧的表面包括四个弧面，具有圆角的所述多边形包括具有圆角的四边形；
    或者，所述谐振结构具有三个通孔，所述改性结构靠近所述谐振结构一侧的表面包括三个弧面，具有圆角的所述多边形包括具有圆角的三角形。
  10. 根据权利要求6所述的滤波器单元，其中，所述环形面包括相连的第一环形面和第二环形面，所述第二环形面位于所述第一环形面与所述谐振结构之间；所述第一环形面的部分与所述改性结构直接接触；所述第一环形面与所述第二环形面不共面。
  11. 根据权利要求10所述的滤波器单元，其中，所述第一环形面所占的空间小于所述第二环形面所占的空间。
  12. 根据权利要求10所述的滤波器单元，其中，所述第二环形面与所述谐振结构靠近所述衬底的一侧之间的夹角范围包括80-88°。
  13. 根据权利要求1所述的滤波器单元，其中，所述改性结构的材料的刻蚀速率大于所述支撑结构的材料的刻蚀速率。
  14. 根据权利要求3所述的滤波器单元，其中，所述滤波器单元还包括支撑层，所述支撑层设置在所述改性结构和所述谐振结构之间；
    所述通孔还贯穿所述支撑层、且与所述空腔连通。
  15. 根据权利要求1所述的滤波器单元，其中，所述改性结构的材料包括玻璃。
  16. 一种电子设备，其中，包括权利要求1-15任一项所述的至少三个滤波器单元，至少三个所述滤波器单元中的至少两个滤波器单元串联、且与除串联的所述滤波器单元以外的其它所述滤波器单元并联。
  17. 一种如权利要求1-15任一项所述的滤波器单元的制备方法，其中，所述方法包括：
    形成衬底；
    在所述衬底的一侧形成谐振结构；所述谐振结构与所述衬底之间具有空腔。
  18. 根据权利要求17所述的滤波器单元的制备方法，其中，所述形成衬底包括：
    提供衬底；
    对所述衬底进行改性，形成改性部和支撑结构；所述支撑结构围绕所述改性部。
  19. 根据权利要求18所述的滤波器单元的制备方法，其中，所述在所述衬底的一侧形成谐振结构；所述谐振结构与所述衬底之间具有空腔包括：
    在所述谐振结构上形成至少一个通孔；
    通过所述通孔注入腐蚀液腐蚀所述改性部，形成改性结构、以及所述改性结构与所述谐振结构之间的空腔。
PCT/CN2022/106158 2022-07-18 2022-07-18 一种滤波器单元及其制备方法、电子设备 WO2024016095A1 (zh)

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Publication number Priority date Publication date Assignee Title
CN105428218A (zh) * 2015-12-10 2016-03-23 杭州士兰微电子股份有限公司 空腔形成方法以及半导体器件结构
CN106365109A (zh) * 2015-07-24 2017-02-01 中芯国际集成电路制造(上海)有限公司 一种mems器件及其制备方法、电子装置
CN112039460A (zh) * 2019-07-19 2020-12-04 中芯集成电路（宁波）有限公司 薄膜体声波谐振器及其制作方法
CN114256273A (zh) * 2020-09-22 2022-03-29 格芯(美国)集成电路科技有限公司 具有腔结构的绝缘体上半导体晶片

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106365109A (zh) * 2015-07-24 2017-02-01 中芯国际集成电路制造(上海)有限公司 一种mems器件及其制备方法、电子装置
CN105428218A (zh) * 2015-12-10 2016-03-23 杭州士兰微电子股份有限公司 空腔形成方法以及半导体器件结构
CN112039460A (zh) * 2019-07-19 2020-12-04 中芯集成电路（宁波）有限公司 薄膜体声波谐振器及其制作方法
CN114256273A (zh) * 2020-09-22 2022-03-29 格芯(美国)集成电路科技有限公司 具有腔结构的绝缘体上半导体晶片

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