CN116155222A - Resonator, manufacturing method thereof, filter and electronic equipment - Google Patents

Resonator, manufacturing method thereof, filter and electronic equipment Download PDF

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Publication number
CN116155222A
CN116155222A CN202211532736.4A CN202211532736A CN116155222A CN 116155222 A CN116155222 A CN 116155222A CN 202211532736 A CN202211532736 A CN 202211532736A CN 116155222 A CN116155222 A CN 116155222A
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Prior art keywords
resonator
support structure
substrate
hole
layer
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李林萍
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Jianwenlu Zhejiang Semiconductor Co ltd
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Jianwenlu Zhejiang Semiconductor Co ltd
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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
    • 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
    • H03H3/04—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 for obtaining desired frequency or temperature coefficient
    • 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
    • H03H9/02102—Means for compensation or elimination of undesirable effects of temperature influence
    • 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
    • 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
    • H03H3/04—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 for obtaining desired frequency or temperature coefficient
    • H03H2003/0407—Temperature coefficient

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)

Abstract

The invention proposes a resonator comprising: a substrate; the functional layer is positioned on the substrate and at least comprises a bottom electrode, a piezoelectric layer and a top electrode, and the piezoelectric layer is positioned between the bottom electrode and the top electrode; a cavity is formed between the bottom electrode and the substrate; the functional layer is provided with a through hole, and at least part of the inner side wall of the through hole is provided with a first supporting structure which is provided with a bottom contacted with the substrate. In this structure, no heat is generated at the through hole; the through holes enable the resonator to be annular, so that a good heat dissipation effect is achieved; the bottom of the first supporting structure is contacted with the substrate, so that a good support is formed for the functional layer, a heat transfer path is formed, the heat transmission of the resonator is quickened, and the heat dissipation capacity of the resonator is enhanced. The invention also provides a manufacturing method of the resonator, and a filter and electronic equipment comprising the resonator.

Description

Resonator, manufacturing method thereof, filter and electronic equipment
Technical Field
The invention belongs to the technical field of semiconductors, and particularly relates to a resonator, a manufacturing method thereof, a filter and electronic equipment.
Background
Thin film bulk acoustic resonators (Film Bulk Acoustic Resonator, FBAR) have been playing an important role in the field of communications because they have excellent characteristics such as small size, high resonant frequency, high quality factor, and large power capacity.
The main structure of a common air gap resonator consists of a bottom electrode layer, a piezoelectric layer and a top electrode layer, namely a layer of piezoelectric material is sandwiched between two metal electrode layers. The working principle is that an electric signal is input between two layers of metal electrodes, the piezoelectric film converts the input electric signal into a mechanical resonance wave by using the inverse piezoelectric effect, and then converts the mechanical resonance wave into an electric signal for output by using the piezoelectric effect. The bottom electrode, the piezoelectric layer and the top electrode are stacked above the substrate, and the surface of the substrate is etched to form a cavity, and the cavity can well limit sound waves in the piezoelectric oscillation stack.
In general, heat generated during the operation of the resonator can only depend on the lateral transfer of heat between the electrode layer and the piezoelectric layer and then be diffused into the substrate, and the central area of the resonator is far away from the substrate, so that the heat in the central area cannot be timely conducted out, the temperature of the resonator rises, the device performance drifts towards low frequency, material damage can occur in the central area in a long-term high-temperature working state, the device is invalid, and the service life of the device is drastically reduced. Particularly at high frequencies, the thicknesses of the electrode layer and the piezoelectric layer are thinner, the heat transmission efficiency is lower, and the heat is increased compared with the low frequencies, so that the heat born by the working area of the device is increased in multiple. Therefore, for the high-power FBAR, the resonator structure in the prior art has uneven heat distribution and low heat dissipation efficiency, and cannot meet the power tolerance level.
Disclosure of Invention
To alleviate or solve the above-mentioned problems, the present invention proposes in a first aspect a resonator comprising:
a substrate; the functional layer is positioned on the substrate and at least comprises a bottom electrode, a piezoelectric layer and a top electrode, and the piezoelectric layer is positioned between the bottom electrode and the top electrode; a cavity is formed between the bottom electrode and the substrate; the functional layer is provided with a through hole, and at least part of the inner side wall of the through hole is provided with a first supporting structure which is provided with a bottom contacted with the substrate.
The technical effects of the resonator structure include that in the resonator, the functional layer at the through hole is partially removed, so that resonance is not generated and heat is not generated; the through holes enable the resonator to be annular, so that a good heat dissipation effect is achieved; the bottom of the supporting structure is contacted with the substrate, so that a good support is formed for the functional layer, and the mechanical stability of the ring resonator is enhanced; the bottom of the first supporting structure is contacted with the substrate, and a heat transfer path can be formed, so that heat in the resonator flows into the substrate through the supporting structure, the heat transmission of the resonator is accelerated, and the heat dissipation capacity of the resonator is enhanced.
Preferably, the first support structure extends from one of the bottom electrode, the piezoelectric layer, or the top electrode along the inner sidewall of the through hole to the bottom surface of the cavity. The material of the bottom electrode, the piezoelectric layer or the top electrode generally has higher heat conductivity coefficient relative to the substrate, so that the support structure formed by extending one layer of the bottom electrode, the piezoelectric layer or the top electrode can accelerate the heat transmission of the resonator; meanwhile, the support structure and the bottom electrode, the piezoelectric layer or the top electrode can be formed at the same time, so that the process can be simplified, and the production is convenient.
Further, the first support structure extends to the bottom of the through hole and covers at least a portion of the bottom surface of the cavity corresponding to the bottom of the through hole. The preferred solution enables the first support structure to cover at least part of the substrate bottom, improving its support effect and heat conduction capability.
Further, the inner side wall of the through hole of the functional layer is vertical, inclined or stepped. In the preferred scheme, the shape of the inner side wall of the through hole can be various and can be set according to actual process conditions.
Preferably, the through-hole inner side wall of the functional layer is stepped, and the first support structure extends from a part of the upper surface of one of the bottom electrode, the piezoelectric layer, or the top electrode along the through-hole to the bottom surface of the cavity. The inner side wall of the through hole forms a step shape to form a position with abrupt morphology, so that transverse waves can be effectively reflected, and the transverse waves are limited in the range of an effective resonance area (namely the area where the bottom electrode, the piezoelectric layer and the top electrode are overlapped with the cavity).
Further, the first support structure completely covers the inner side wall of the through hole or is discontinuously distributed along the inner side wall of the through hole.
Preferably, the through hole is located in the central region of the resonator. In general, the central region of the resonator is the region where heat is most concentrated, and the through hole is provided in the central region, so that the overheating of the central region can be effectively reduced.
Further, the projection shape of the through hole on the substrate is circular, elliptical or polygonal. The through holes may be provided in any shape according to actual needs.
Further, the first support structure is the same material as the bottom electrode, the piezoelectric layer, or the top electrode.
Preferably, a second support structure is further provided above the first support structure, the second support structure covering at least part of the first support structure. The multi-layered support structure may further increase structural strength while improving electrical conductivity.
Further, the second support structure extends from the outside of one of the bottom electrode, the piezoelectric layer or the top electrode to at least part of the surface of the first support structure to cover a partial area of the first support structure.
Further, the second support structure is the same material as the first support structure. When the first support structure extends from the bottom electrode, if the second support structure is made of metal material, the effect of improving the conductivity of the bottom electrode and reducing the series impedance is achieved.
Further, the second support structure is of a different material than the first support structure. At this time, the mechanical stability of the resonator can be improved by the second support structure. Further, the functional layer may further include one or more of a passivation layer, a support layer, a seed layer, or a temperature compensation layer. The first support structure and the second support structure can be formed by extending functional layers including a passivation layer, a support layer, a seed layer or a temperature compensation layer.
Further, the cavity is located on the upper surface of the substrate or embedded inside the substrate. The resonator of the present application is suitable for use in either above-ground or below-ground cavities.
Preferably, the height of the cavity is less than 2 μm. Further preferably, the height of the cavity is 0.5-1.5 μm. The cavity height can be greatly reduced, so that the process cost can be reduced, and meanwhile, the heat dissipation path is shorter and the heat dissipation effect is better.
The present invention in a second aspect proposes a method of manufacturing a resonator, comprising the steps of:
providing a substrate; forming a cavity on a substrate; forming a functional layer on the cavity and the substrate, and forming a through hole in the functional layer in the process of forming the functional layer, wherein the functional layer at least comprises a bottom electrode, a piezoelectric layer and a top electrode; wherein a first support structure is formed on at least a portion of the inner side wall of the through hole, the first support structure extending from the inner side wall of the through hole to the bottom surface of the cavity.
Further, in the manufacturing method, the first support structure is integrally formed with the functional layer.
Further, in the manufacturing method, the first support structure and the top electrode are formed in the same layer, and a fracture is formed between the first support structure and the top electrode so as to realize electrical isolation.
The invention proposes in a third aspect a filter comprising a resonator as described above.
The invention proposes in a fourth aspect an electronic device comprising a resonator as described above.
According to the resonator provided by the invention, through the through holes are arranged on the functional layer, resonance is not generated at the corresponding positions of the through holes, and heat generation is effectively reduced; at least part of the inner side walls of the through holes are provided with supporting structures which provide effective support for the functional layer; the support structure has a bottom in contact with the substrate, allowing heat to flow into the substrate through the support structure, improving the heat dissipation efficiency of the resonator.
Drawings
The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and together with the description serve to explain the principles of the invention. Many of the intended advantages of other embodiments and embodiments will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts.
FIG. 1 shows a cross-sectional view of a resonator according to one embodiment of the invention;
FIG. 2 is a schematic diagram of a heat transfer path of a conventional resonator of the prior art;
FIG. 3 is a thermodynamic diagram corresponding to the resonator shown in FIG. 2;
FIG. 4 is a schematic diagram of a heat transfer path of the resonator shown in FIG. 1;
FIG. 5 is a thermodynamic diagram corresponding to the resonator shown in FIG. 1;
fig. 6 shows a cross-sectional view of a resonator according to another embodiment of the invention;
FIG. 7 is an enlarged view of a portion of the inner sidewall of the through hole of the resonator shown in FIG. 1;
FIG. 8 is a top view of the resonator shown in FIG. 1;
fig. 9 shows a cross-sectional view of a resonator according to another embodiment of the invention;
fig. 10 shows a cross-sectional view of a resonator according to another embodiment of the invention;
FIG. 11 shows a cross-sectional view of a resonator according to another embodiment of the invention;
fig. 12 shows a cross-sectional view of a resonator according to another embodiment of the invention;
fig. 13 shows a cross-sectional view of a resonator according to another embodiment of the invention;
fig. 14 shows a cross-sectional view of a resonator according to another embodiment of the invention;
fig. 15a-15i show a process flow diagram of the fabrication of a thin film bulk acoustic resonator in accordance with one embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Because components of embodiments can be positioned in a number of different orientations, some embodiments will be described using directional terminology, such as "top," "bottom," "left," "right," "up," "down," etc., with reference to the orientation of the figure. It is to be understood that the directional terminology is used for purposes of illustration and not limitation. Other embodiments may be utilized and logical changes may be made without departing from the innovative scope of the invention. Embodiments and features of embodiments in this application may be combined with each other without conflict.
Fig. 1 shows a cross-sectional view of a resonator 100 according to an embodiment of the invention, fig. 8 is a top view of the resonator 100, wherein the cross-section refers to a plane perpendicular to the resonator substrate and passing through two non-adjacent sides of the opening of the support structure, in particular reference may be made to section A-A' in fig. 8, and the top view refers to the top view of the resonator when the substrate is the bottom plane. Referring to fig. 1, a resonator 100 includes a substrate 101; a functional layer on the substrate 101, the functional layer including at least a bottom electrode 103, a piezoelectric layer 104, and a top electrode 105, the piezoelectric layer 104 being located between the bottom electrode 103 and the top electrode 105; a cavity 102 is provided between the bottom electrode 103 and the substrate 101; wherein the functional layer has a through hole, at least part of the inner side wall of the through hole is provided with a first supporting structure 106, and the first supporting structure 106 has a bottom contacting the substrate 101. The region where the through hole is located does not generate resonance, so that no heat is generated, and the heat generation in the resonator is reduced; after the through holes are formed, the effective resonance area is annular, and the annular structure is beneficial to heat dissipation. The support structure may improve the stability of the resonator: the conventional resonator mainly depends on the edge of the bottom electrode for supporting, the area of the resonator is larger at low frequency, the piezoelectric layer and the thickness of the electrode are very thin at high frequency, so that the structural strength of the resonator is reduced, and according to the supporting structure provided by the embodiment, the stability of the resonator can be enhanced, the mechanical reliability is improved, and meanwhile, the effective area of the resonator is ensured; in addition, the supporting structure can also be used as a heat conduction path to transfer heat into the substrate through the supporting structure, and compared with a conventional resonator structure, the heat dissipation efficiency of the resonator is improved.
Fig. 2-5 further illustrate that the support structure may effectively enhance the heat dissipation efficiency of the resonator. Fig. 2 is a schematic diagram of a heat transfer path of a resonator 100 'commonly known in the prior art, and fig. 3 is a thermodynamic diagram corresponding to the resonator 100', wherein numerals in the thermodynamic diagram indicate temperature values thereat. A common resonator 100 'comprises a substrate 101'; a bottom electrode 103', a piezoelectric layer 104', and a top electrode 105' on the substrate 101', the piezoelectric layer 104' being located between the bottom electrode 103' and the top electrode 105 '; a cavity 102' is provided between the bottom electrode 103' and the substrate 101'; the heat transfer path is shown by the arrow in fig. 2, and since air is a poor conductor of heat, the resonator 100' transfers heat to a portion of the substrate in the vicinity of the resonator mainly through the electrode and the piezoelectric layer, which in turn transfers heat to the entire substrate for external transfer. In general, the distance between the central area of the effective resonant area and the substrate at the side of the cavity is far, that is, the distance of heat transmission is far, and heat cannot be conducted out in time, so that heat accumulation occurs in the central area a of the resonator, and as shown in fig. 3, the central area a of the resonator is overheated, which easily causes frequency drift of the resonator, or causes and accelerates aging of the piezoelectric laminated structure, and affects the performance of the resonator. Fig. 4 is a schematic diagram of a heat transfer path of the resonator 100, and fig. 5 is a thermodynamic diagram corresponding to the resonator 100, where numerals in the thermodynamic diagram indicate temperature values. As shown in fig. 4, the region where the through hole of the resonator is located does not resonate any more, thereby reducing heat generation; meanwhile, the supporting structure is in contact with the substrate, heat is transferred from the supporting structure to the substrate, a heat dissipation path is increased, and the heat dissipation capacity of the resonator is improved. As can be seen from comparing fig. 3 and 5, the operating temperature range of the resonator 100' is about 313K-343K, the highest temperature occurs in the central region of the resonator, and the temperature distribution gradually decreases outward with the central region of the resonator as the center; and the operating temperature range of the resonator 100 is about 298K-313K, compared with the resonator 100', the heat in the central region of the resonator is the lowest, and the highest temperature occurs between the outer edge of the concave region and the outer edge of the resonator and is distributed in a ring shape. Therefore, the overall heat of the resonator in the embodiment is greatly reduced, the heat distribution is more uniform, and the long-term working performance of the resonator is greatly improved.
In a preferred embodiment, the first support structure extends from one of the bottom electrode, the piezoelectric layer, or the top electrode along the inner sidewall of the through hole to the bottom surface of the cavity. In the following, a detailed description will be given taking an example that the first support structure extends from the top electrode or the piezoelectric layer along the inner sidewall of the through hole to the bottom surface of the cavity, and referring to fig. 1, the first support structure 106 extends from the top electrode 105 along the inner sidewall of the through hole to the bottom surface of the cavity 102, and at the edge of the effective resonance area, a break 108 is formed between the top electrode 105 and the first support structure 106 to achieve electrical isolation, so as to avoid a short circuit between the electrodes. Fig. 6 is a cross-sectional view of a resonator 200 in another preferred embodiment, wherein the cross-section refers to a plane perpendicular to the resonator substrate and passing through two non-adjacent sides of the opening of the support structure. In this embodiment, the resonator 200 includes a substrate 201; a functional layer on the substrate 201, the functional layer including at least a bottom electrode 203, a piezoelectric layer 204, and a top electrode 205, the piezoelectric layer 204 being located between the bottom electrode 203 and the top electrode 205; a cavity 202 is provided between the bottom electrode 203 and the substrate 201; wherein the functional layer has a through hole, at least a portion of the inner sidewall of the through hole is provided with a first support structure 206, which is different from the resonator 100 mainly in that the first support structure 206 extends from the piezoelectric layer 204 along the inner sidewall of the through hole to the bottom surface of the cavity 202.
The beneficial effects of arranging the first support structure to extend from one of the bottom electrode, the piezoelectric layer or the top electrode include that in the prior art, the material of the bottom electrode, the piezoelectric layer or the top electrode generally has a higher thermal conductivity than the substrate, see table 1, wherein Si is a common material of the substrate, mo is a common material of the electrode, ALN is a common material of the piezoelectric layer, and it is seen that the thermal conductivity of the substrate is much smaller than the thermal conductivity of the functional layer of the resonator, and the heat transfer of the resonator can be accelerated by transferring the heat of the resonator through the functional layer. Meanwhile, the first supporting structure and the bottom electrode, the piezoelectric layer or the top electrode can be formed simultaneously during production, so that the process is simplified. In other embodiments, the first support structure may be formed by other processes, and the materials are different from the electrode and the piezoelectric layer according to actual needs.
Table 1 thermal conductivity coefficients of common materials for different structures in resonators
Figure BDA0003975051080000061
In a preferred embodiment, referring to fig. 1, the first support structure 106 extends to the bottom of the through hole and further covers at least a portion of the bottom surface of the cavity 102 corresponding to the bottom of the through hole. At this time, the first supporting structure completely covers the bottom of the through hole and covers part of the surface of the substrate, so that the substrate has a larger supporting area. It should be noted that, the contact area between the support structure and the substrate may be equal to the area of the bottom of the through hole, or greater than the area of the bottom of the through hole or less than the area of the bottom of the through hole.
In particular embodiments, the shape of the inner sidewall of the via may be vertical, or sloped, or stepped, such that the via is perpendicular to the substrate, or sloped to the substrate surface, and the inner sidewall may have a stepped shape. In a preferred embodiment, during the manufacture of the resonator, a part of the upper surface of at least one of the bottom electrode, the piezoelectric layer or the top electrode is exposed in the through hole, such that the through hole inner side wall of the functional layer forms a step shape, and the first support structure extends from the part of the upper surface of one of the bottom electrode, the piezoelectric layer or the top electrode along the through hole to the bottom surface of the cavity.
In a further preferred embodiment, referring to fig. 1, the first support structure 106 extends from a part of the upper surface of the piezoelectric layer 104 along the inner side wall of the through hole to the bottom surface in the cavity 102, and the first support structure 106 may be formed simultaneously with the top electrode 105 during the manufacturing process of the resonator. Fig. 7 is an enlarged view of the inner structure of the virtual coil of fig. 1 of the resonator 100, in which three steps are formed on the inner side wall of the through hole at the position indicated by the arrow, so that the step has a shape mutation, and the shape mutation at the edge of the functional layer can reflect the transverse wave, so that the transverse wave is limited in the effective resonance area.
In another preferred embodiment, referring to fig. 6, a portion of the upper surface of the piezoelectric layer 204 is exposed in the through hole, such that the inner sidewall of the through hole forms a step at the arrow, thereby having a topographical abrupt change, and the topographical abrupt change at the edge of the functional layer can reflect the transverse wave, limiting the transverse wave to the effective resonant area.
In a specific embodiment, according to practical needs, the first supporting structure may be continuous, so that the first supporting structure completely covers the inner side wall of the through hole, or may be discontinuously distributed along the inner side wall of the through hole, so as to achieve the supporting effect.
In a preferred embodiment, the through hole is located in the central region of the resonator. Referring to fig. 8, the through hole is located within the central region of the resonator 100. Referring to fig. 3, for a conventional resonator, the center region is typically the region where heat accumulation is most severe due to the greater distance from the cavity side substrate. The through hole is arranged in the central area of the resonator, so that the overheat condition of the central area can be effectively reduced. It will be appreciated that the through holes may also be arranged off-centre.
The cross-sectional shape of the through hole is not limited, and the through hole can be round, elliptic, regular polygons with each angle larger than 90 degrees or irregular polygons with each angle larger than 90 degrees, and the length-width ratio and the like of the through hole can be adjusted according to the requirements. Referring to fig. 8, in the present embodiment, the through-hole shape of the resonator 100 is set to an irregular pentagon.
In a specific embodiment, the first support structure may be formed simultaneously with the corresponding membrane layer during the manufacturing process, as the material of the bottom electrode, the piezoelectric layer or the top electrode is the same as the actual need arises.
In a preferred embodiment, a second support structure is further provided above the first support structure, and the second support structure covers at least part of the first support structure. In particular, reference is made to the cross-sectional view of the resonator 300 shown in fig. 9, wherein the cross-section refers to a plane perpendicular to the resonator substrate and passing through two non-adjacent sides of the opening of the support structure. Similar to resonator 100, resonator 300 includes substrate 301; a functional layer on the substrate 301, the functional layer including at least a bottom electrode 303, a piezoelectric layer 304, and a top electrode 305, the piezoelectric layer 304 being located between the bottom electrode 303 and the top electrode 305; a cavity 302 is provided between the bottom electrode 303 and the substrate 301; the functional layer has a through hole therein, and a first support structure 3061 is provided on at least a portion of an inner sidewall of the through hole, the first support structure 3061 extending from the bottom electrode 303 along the inner sidewall of the through hole to a bottom surface of the cavity 302. The main difference from the resonator 100 is that a second support structure 3062 is further included above the first support structure 3061, the second support structure 3062 extending from the outside of the top electrode 305 to the surface of the first support structure 3061, and at the edge of the effective resonance area, a break 308 is provided between the top electrode 305 and the second support structure 3062 to achieve electrical isolation, avoiding a short circuit between the electrodes. The first and second support structures are preferably formed simultaneously with the bottom electrode and the top electrode, respectively, and the multilayer metal superposition improves the conductivity of the bottom electrode, can reduce the series impedance Rs of the resonator, and improves the performance of the resonator, besides the technical effects described above. It is understood that the first support structure and the second support structure may be formed of any two layers of the functional layers, and are not limited to the combination of the bottom electrode and the top electrode.
In a specific embodiment, the materials of the second support structure and the first support structure may be the same material or different materials according to actual needs. When the second support structure is different from the first support structure in material, the mechanical stability of the functional layer in the resonator can be improved by providing the second support structure.
In preferred embodiments, the functional layer may further comprise one or more of a passivation layer, a support layer, a seed layer, or a temperature compensation layer. Fig. 10 is a cross-sectional view of a resonator 400 in another preferred embodiment of the invention, wherein the cross-section refers to a plane perpendicular to the resonator substrate and passing through two non-adjacent sides of the opening of the support structure. Similar to resonator 100, resonator 400 includes substrate 401; a functional layer on the substrate 401, the functional layer including at least a bottom electrode 403, a piezoelectric layer 404, and a top electrode 405, the piezoelectric layer 404 being located between the bottom electrode 403 and the top electrode 405; a cavity 402 is provided between the bottom electrode 403 and the substrate 401; the functional layer has a through hole therein, and a first support structure 406 is disposed on at least a portion of an inner sidewall of the through hole, which is different from the resonator 100 mainly in that the functional layer of the resonator 400 further includes a passivation layer 407 disposed on a top layer, and the first support structure 406 extends from the passivation layer 407 along the inner sidewall of the through hole to a bottom surface of the cavity 402. The passivation layer 407 may effectively protect the resonator from the external environment, and the first support structure 406 may be formed simultaneously with the passivation layer 407, so that the resonator 400 has good mechanical strength and temperature stability. It will be appreciated that if a support layer, seed layer or temperature compensation layer is included in the resonator, the support structure may also be formed from one or more of the support layer, seed layer or temperature compensation layer.
In a specific embodiment, the cavity may be disposed on the upper surface of the substrate or embedded in the substrate to form an above-ground cavity or an underground cavity according to actual needs. Fig. 11 is a cross-sectional view of a resonator 500 in another preferred embodiment of the invention, wherein the cross-section refers to a plane perpendicular to the resonator substrate and passing through two non-adjacent sides of the opening of the support structure. Similar to resonator 100, resonator 500 includes substrate 501; a functional layer on the substrate 501, the functional layer including at least a bottom electrode 503, a piezoelectric layer 504, and a top electrode 505, the piezoelectric layer 504 being located between the bottom electrode 503 and the top electrode 505; a cavity 502 is provided between the bottom electrode 503 and the substrate 501; wherein the functional layer has a through hole, at least part of the inner side wall of the through hole is provided with a first supporting structure 506, and the first supporting structure 506 has a bottom contacting the substrate 501. The main difference from the resonator 100 is that the surface of the substrate 501 is not etched, and the cavity 502 is entirely located above the substrate 501, forming an above-ground cavity structure.
Fig. 12-14 are cross-sectional views of resonators in other preferred embodiments of the invention, where cross-section refers to a plane perpendicular to the resonator substrate and passing through two non-adjacent sides of an opening of a support structure. The resonators shown in fig. 12 to 14 are all of a cavity structure of a ground type and have a first support structure extending from one of the bottom electrode, the piezoelectric layer, or the top electrode along the inner side wall of the through hole to the bottom surface of the cavity, or have a first support structure and a second support structure extending from different ones of the functional layers.
Specifically, the resonator 600 shown in fig. 12 has a structure similar to that of the resonator 200, and includes a substrate 601, a bottom electrode 603, a piezoelectric layer 604, a top electrode 605, a cavity 602, and a first support structure 606, and is different from the resonator 200 mainly in that the cavity 602 of the resonator 600 is integrally located above the substrate 601, forming a ground-type cavity structure.
Specifically, the resonator 700 shown in fig. 13 is similar in structure to the resonator 300, and includes a substrate 701, a bottom electrode 703, a piezoelectric layer 704, a top electrode 705, a cavity 702, a first support structure 7061 and a second support structure 7062, the first support structure 7061 extending from the bottom electrode 703 to a bottom surface of the cavity 702 along an inner side wall of the through hole, and the second support structure 7062 above the first support structure 7061 extending from an outer side of the top electrode 705 to a surface of the first support structure 7061, and is different from the resonator 300 in that the cavity 702 of the resonator 700 is entirely located above the substrate 701, forming an above-ground cavity structure.
Specifically, the resonator 800 shown in fig. 14 has a structure similar to that of the resonator 400, and includes a substrate 801, a bottom electrode 803, a piezoelectric layer 804, a top electrode 805, a cavity 802, and a first support structure 806, and the functional layer further includes a passivation layer 807 disposed on top, and the first support structure 806 extends from the passivation layer 807 to a bottom surface of the cavity 802 along an inner sidewall of the through hole, unlike the resonator 400 in that the cavity 802 of the resonator 800 is entirely located over the substrate 801, forming a ground-type cavity structure.
In the preferred embodiment, the supporting structure provides support for the functional layer, so that the supporting effect of the cavity is enhanced, the situation that the central area of resonance is collapsed and adhered to the substrate can be avoided, compared with the cavity with the common height of 2-3 μm in the existing resonator, the height of the cavity of the resonator in the preferred embodiment can be smaller than 2 μm, preferably, the height range of the cavity is 0.5-1.5 μm, the filled sacrificial material is reduced, the process cost is further reduced, meanwhile, the height of the cavity is reduced, the heat dissipation path of the resonator is shortened, and the heat dissipation effect is further improved.
According to a second aspect of the invention, in a specific embodiment, a method of manufacturing a resonator comprises the steps of:
providing a substrate; forming a cavity on a substrate; forming a functional layer on the cavity and the substrate, and forming a through hole in the functional layer in the process of forming the functional layer, wherein the functional layer at least comprises a bottom electrode, a piezoelectric layer and a top electrode; wherein a first support structure is formed on at least a portion of the inner side wall of the through hole, the first support structure extending from the inner side wall of the through hole to the bottom surface of the cavity.
In a preferred embodiment, the first support structure is formed integrally with the functional layer during the manufacturing of the resonator.
In a further preferred embodiment, the first support structure is formed in the same layer as the top electrode, and a break is provided between the first support structure and the top electrode to achieve electrical isolation.
Fig. 15a-15i are schematic views of a manufacturing process of a resonator 900 according to an embodiment of the present invention, wherein a functional layer of the resonator 900 has a through hole therein, and a first support structure is formed in the same layer as a top electrode and extends from an inner sidewall of the through hole to a bottom surface of the cavity, and the manufacturing process specifically includes:
as shown in fig. 15a, a substrate 901 is provided, and the substrate 901 is etched to form a cavity 902; the material of the substrate 901 is preferably Si, sapphire, spinel, or the like;
as shown in fig. 15b, a sacrificial material is deposited on a substrate 901, patterned to form a sacrificial layer 902', and optionally, the sacrificial layer 902' is subjected to CMP (chemical mechanical polishing) so that a central region thereof is recessed downward to expose a portion of the substrate 901; the preferred material for the sacrificial layer 902' is PSG (P-doped SiO 2 )；
As shown in fig. 15c, on the sacrificial layer 902', a bottom electrode layer 903 is formed by sputtering, photolithography, etching, or the like, and a preferable material is molybdenum (Mo), and other optional materials are metal materials or alloy materials of gold (Au), tungsten (W), copper (Cu), nickel (Ni), titanium (Ti), niobium (Nb), silver (Ag), tantalum (Ta), cobalt (Co), aluminum (Al), or the like;
as shown in fig. 15d, the central region of the bottom electrode 903 is removed by etching the bottom electrode 903 to expose the substrate in the central region and a portion of the edge horizontal surface of the sacrificial layer 902';
as shown in FIG. 15e, the piezoelectric layer 904 is grown continuously, and the piezoelectric layer 904 is preferably made of aluminum nitride (AlN), and zinc oxide (ZnO), zinc sulfide (ZnS), lithium tantalate (LiTaO) 3 ) Cadmium sulfide (CdS), lead titanate (PbTiO) 3 ) Lead zirconate titanate (Pb (Zr, ti) O 3 ) Etc.;
as shown in fig. 15f, the piezoelectric layer 904 is etched until the substrate 901 and the sacrificial layer 902' of the central region are exposed, and a part of the edge horizontal surface of the bottom electrode 903;
as shown in fig. 15g, the top electrode 905 and the first support structure 906 are fabricated simultaneously by a sputtering process, preferably molybdenum (Mo), and other optional materials are metal materials or alloy materials such as gold (Au), tungsten (W), copper (Cu), nickel (Ni), titanium (Ti), niobium (Nb), silver (Ag), tantalum (Ta), cobalt (Co), or aluminum (Al);
as shown in fig. 15h, the top electrode 905 is etched at a position corresponding to the edge of the effective resonance region to form a fracture 908; the break 908 in effect physically separates the top electrode 905 from the first support structure 906, ultimately achieving electrical isolation from each other. Those skilled in the art will appreciate that the fracture may be referred to as a groove in a top view;
as shown in fig. 15i, the sacrificial layer 902' is released, forming a cavity 902.
Although the steps of the method are recited in a certain order, it will be understood by those skilled in the art that the steps may be performed in an order different from the above, i.e., the steps may be performed in an opposite or parallel manner. The detailed description of each structural layer is shown in the description of the content of the device, and will not be repeated here.
According to the resonator provided by the invention, the through holes are formed in the functional layer to form the ring resonator, so that the technical problem of overhigh temperature in the central area of the resonator is solved; the support structure is arranged on at least part of the inner side wall of the through hole, so that the technical problem of poor mechanical stability of the resonator is solved; the support structure is provided with a bottom which is contacted with the substrate, so that the technical problem of slow heat dissipation of the resonator is solved; the inner side wall of the through hole is formed into a step shape, so that transverse wave leakage of the resonator is reduced. The structure can meet the performance requirements of high-frequency and high-power devices, enhance the reliability of the resonator and prolong the long-term service life.
While the present invention has been described with reference to the specific embodiments thereof, the scope of the present invention is not limited thereto, and any changes or substitutions will be apparent to those skilled in the art within the scope of the present invention, and are intended to be covered by the present invention. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (22)

1. A resonator, comprising:
a substrate;
the functional layer is positioned on the substrate and at least comprises a bottom electrode, a piezoelectric layer and a top electrode, and the piezoelectric layer is positioned between the bottom electrode and the top electrode;
a cavity is formed between the bottom electrode and the substrate;
the functional layer is provided with a through hole, and at least part of the inner side wall of the through hole is provided with a first supporting structure, and the first supporting structure is provided with a bottom contacted with the substrate.
2. The resonator of claim 1, wherein the first support structure extends from one of the bottom electrode, the piezoelectric layer, or the top electrode along an inner sidewall of the via to a bottom surface of the cavity.
3. The resonator according to claim 1, characterized in that the first support structure extends to the bottom of the through hole and covers at least a part of the bottom surface of the cavity corresponding to the bottom of the through hole.
4. The resonator according to claim 1, characterized in that the inner side walls of the through holes of the functional layer are vertical, or inclined, or stepped.
5. The resonator according to claim 4, characterized in that the inner side wall of the through hole of the functional layer is stepped and the first support structure extends from a part of the upper surface of one of the bottom electrode, the piezoelectric layer or the top electrode along the through hole to the bottom surface of the cavity.
6. The resonator of claim 1, wherein the first support structure completely covers the inner sidewall of the through hole or is discontinuously distributed along the inner sidewall of the through hole.
7. The resonator according to claim 1, characterized in that the through hole is located in a central area of the resonator.
8. The resonator according to claim 1, characterized in that the projection shape of the through hole on the substrate is circular, elliptical or polygonal.
9. The resonator according to claim 1, characterized in that the first support structure is of the same material as the bottom electrode, the piezoelectric layer or the top electrode.
10. The resonator according to any of claims 1-9, characterized in that the first support structure is further provided with a second support structure above it, which second support structure covers at least part of the first support structure.
11. The resonator of claim 10, wherein the second support structure extends from outside one of the bottom electrode, the piezoelectric layer, or the top electrode to at least a portion of a surface of the first support structure to cover a portion of the area of the first support structure.
12. The resonator of claim 10, wherein the second support structure is the same material as the first support structure.
13. The resonator of claim 10, wherein the second support structure is a different material than the first support structure.
14. The resonator according to any of claims 1-9, characterized in that the functional layer further comprises one or more of a passivation layer, a support layer, a seed layer or a temperature compensation layer.
15. The resonator according to any of claims 1-9, characterized in that the cavity is located on the upper surface of the substrate or embedded inside the substrate.
16. The resonator according to any of claims 1-9, characterized in that the height of the cavity is less than 2 μm.
17. The resonator according to claim 16, characterized in that the height of the cavity is 0.5-1.5 μm.
18. A method of manufacturing a resonator, comprising the steps of:
providing a substrate;
forming a cavity on a substrate;
forming a functional layer on the cavity and the substrate, and forming a through hole in the functional layer in the forming process of the functional layer, wherein the functional layer at least comprises a bottom electrode, a piezoelectric layer and a top electrode;
wherein a first support structure is formed on at least a portion of the inner side wall of the through hole, the first support structure extending from the inner side wall of the through hole to a bottom surface of the cavity.
19. The method of manufacturing a resonator according to claim 18, characterized in that the first support structure is formed integrally with the functional layer.
20. The method of manufacturing a resonator according to claim 19, wherein the first support structure is formed in the same layer as the top electrode with a break between the first support structure and the top electrode to provide electrical isolation.
21. A filter comprising a resonator as claimed in any one of claims 1 to 17.
22. An electronic device comprising the resonator of any one of claims 1-17.
CN202211532736.4A 2022-12-01 2022-12-01 Resonator, manufacturing method thereof, filter and electronic equipment Pending CN116155222A (en)

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Application Number Priority Date Filing Date Title
CN202211532736.4A CN116155222A (en) 2022-12-01 2022-12-01 Resonator, manufacturing method thereof, filter and electronic equipment

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211532736.4A CN116155222A (en) 2022-12-01 2022-12-01 Resonator, manufacturing method thereof, filter and electronic equipment

Publications (1)

Publication Number Publication Date
CN116155222A true CN116155222A (en) 2023-05-23

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Country Status (1)

Country Link
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