Method for manufacturing a resonator and resonator

Abstract

The application provides a resonator manufacturing method and a resonator. The manufacturing method comprises the following steps: providing a first substrate, wherein the first substrate comprises a first piezoelectric layer; forming a first bonding layer on the first piezoelectric layer, wherein the first bonding layer has a first piezoelectricity and covers the first piezoelectric layer; providing a second substrate comprising a second bonding layer, wherein the second substrate has a first end and a second end, the second bonding layer is located at the second end, and the second bonding layer has a second piezoelectricity; forming a damage layer in the second substrate, wherein the damage layer is located at the first end, and the damage layer and the second bonding layer have a part of the second substrate therebetween; bonding the first bonding layer and the second bonding layer to form a first wafer; removing the damage layer and the part of the second substrate at the first end, and the remaining part of the second substrate forms a second piezoelectric layer; forming a bottom electrode and a support part on the second piezoelectric layer, wherein the bottom electrode and the part of the support part are arranged alternately; removing the first substrate to expose the first piezoelectric layer; and forming a top electrode on the first piezoelectric layer.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and more specifically, to a method for manufacturing a resonator and a resonator thereof. Background Technology

[0002] Film bulk acoustic wave resonators (FBARs), surface acoustic wave resonators (SAWs), and bandpass filters are widely used in current communication systems. However, since the electromechanical coupling coefficient K directly affects the filtering bandwidth of the filter, and the quality factor Q directly affects the out-of-band suppression effect, conventional resonators often experience a decrease in Q value when increasing the electromechanical coupling coefficient K, or vice versa. Therefore, it is difficult to simultaneously improve both the electromechanical coupling coefficient K and the quality factor Q in existing FBAR and SAW technologies, making it challenging to further enhance the performance of the resonators and filters. Summary of the Invention

[0003] The main objective of this invention is to provide a method for manufacturing a resonator and a resonator in order to solve the problem that the performance of resonators and filters in the prior art is difficult to further improve.

[0004] To achieve the above objectives, according to one aspect of the present invention, a method for fabricating a resonator is provided, comprising the following steps: providing a first substrate, the first substrate including a first piezoelectric layer having an exposed first surface; forming a first bonding layer on the first surface, the first bonding layer having first piezoelectricity such that the first bonding layer covers the first surface; providing a second substrate including a second bonding layer, the second substrate having opposing first and second ends, the second bonding layer being located at the second end and having second piezoelectricity; forming a damage layer in the second substrate such that the damage layer is located on the side of the first end near the second bonding layer, and a gap exists between the damage layer and the second bonding layer. A portion of the aforementioned second substrate; the aforementioned first bonding layer and the aforementioned second bonding layer are bonded together to form a first wafer; the aforementioned damaged layer and a portion of the aforementioned second substrate on the side of the aforementioned damaged layer away from the aforementioned second bonding layer are removed, and the remaining portion of the aforementioned second substrate forms a second piezoelectric layer, the aforementioned second piezoelectric layer having an exposed second surface, the aforementioned first piezoelectric layer, the aforementioned first bonding layer, the aforementioned second bonding layer and the aforementioned second piezoelectric layer constituting a composite piezoelectric layer; a bottom electrode and a support member are sequentially formed on the aforementioned second surface, the aforementioned bottom electrode and a portion of the aforementioned support member are alternately arranged, the aforementioned support member being used to support the aforementioned composite piezoelectric layer; the aforementioned first substrate is removed to expose the aforementioned first piezoelectric layer; a top electrode is formed on the side of the aforementioned first piezoelectric layer away from the aforementioned second piezoelectric layer.

[0005] Furthermore, the steps for forming the aforementioned damaged layer include: forming the damaged layer using an ion implantation method.

[0006] Furthermore, the first wafer is heat-treated at a temperature of 300℃ to 500℃ under a nitrogen atmosphere.

[0007] Furthermore, the first bonding layer, the second bonding layer, and the first piezoelectric layer are made of the same material, wherein the materials of the first piezoelectric layer, the first bonding layer, and the second bonding layer include at least aluminum nitride.

[0008] Furthermore, the step of forming the first piezoelectric layer includes: forming the first piezoelectric layer on the surface of the first substrate by chemical vapor deposition at a temperature of 1000℃ to 1300℃ and a pressure of 55mbar to 500mbar.

[0009] Further, the steps of forming the bottom electrode and the support member include: forming a bottom electrode on the second surface of the second piezoelectric layer; forming a third bonding layer in a portion of the second surface excluding the bottom electrode, wherein the bottom electrode and the third bonding layer are alternately disposed; providing a third substrate and forming a fourth bonding layer on the third substrate; and bonding the third bonding layer and the fourth bonding layer together.

[0010] Furthermore, the third bonding layer has a minimum spacing with the bottom electrode, which is greater than or equal to 10 μm.

[0011] According to another aspect of the present invention, a resonator is provided, which is manufactured by the above-described manufacturing method.

[0012] Furthermore, the resonator also includes: a third bonding layer disposed on the side of the second piezoelectric layer away from the first piezoelectric layer; a fourth bonding layer disposed on the surface of the third substrate, and the fourth bonding layer is bonded to the third bonding layer; and a cavity disposed on the side of the bottom electrode away from the top electrode, the cavity being formed by the third bonding layer, the fourth bonding layer, the second piezoelectric layer and the third substrate.

[0013] Furthermore, the resonator also includes: a third bonding layer disposed on the side of the second piezoelectric layer away from the first piezoelectric layer, and the third bonding layer having a third surface in contact with the second piezoelectric layer, the second piezoelectric layer completely covering the third surface; and a fourth bonding layer disposed on the surface of the third substrate, and the fourth bonding layer being bonded to the third bonding layer.

[0014] The present invention provides a method for fabricating a resonator. By bonding a first piezoelectric layer and a second piezoelectric layer together, a composite piezoelectric layer is formed, thereby improving the internal structure of the piezoelectric layer. This allows the resonator with the composite piezoelectric layer to not only improve the quality factor Q of the device through the first piezoelectric layer but also improve the electromechanical coupling coefficient K through the second piezoelectric layer. This further enhances the performance of the resonator and the filter containing it. Furthermore, since the composite piezoelectric layer is formed by directly bonding the first and second piezoelectric layers, it overcomes the problem in the prior art where the first and second piezoelectric layers cannot be directly deposited to form the composite piezoelectric layer in the resonator, thus preventing the first and second piezoelectric layers from functioning simultaneously. This achieves the goal of improving the resonator's performance. Attached Figure Description

[0015] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0016] Figure 1 A cross-sectional view of a first substrate having a first piezoelectric layer is shown in a method for fabricating a resonator according to an embodiment of the present invention.

[0017] Figure 2A schematic cross-sectional view of the second substrate provided in a method for fabricating a resonator according to an embodiment of the present invention is shown.

[0018] Figure 3 A schematic cross-sectional view of the first wafer formed after bonding the first and second substrates is shown.

[0019] Figure 4 A cross-sectional schematic diagram is shown, showing the bottom electrode formed on the side of the second piezoelectric layer away from the first piezoelectric layer after the formation of the composite piezoelectric layer.

[0020] Figure 5 A cross-sectional schematic diagram of a third bonding layer formed on the side of the second piezoelectric layer away from the first piezoelectric layer is shown.

[0021] Figure 6 A cross-sectional schematic diagram showing a fourth bonding layer formed on one side of a provided third substrate is shown;

[0022] Figure 7 A schematic cross-sectional view of the structure after the third substrate is bonded to the composite piezoelectric layer is shown.

[0023] Figure 8 A cross-sectional schematic diagram is shown, showing the removal of the first substrate and the formation of a top electrode on the side of the first piezoelectric layer away from the second piezoelectric layer.

[0024] Figure 9 A cross-sectional structural diagram of another resonator formed according to a method for manufacturing a resonator according to an embodiment of the present invention is shown.

[0025] The above figures include the following reference numerals:

[0026] 10. First substrate; 20. First piezoelectric layer; 30. Second substrate; 40. Damaged layer; 50. First bonding layer; 60. Second bonding layer; 70. First bonding material layer; 80. Second piezoelectric layer; 90. Bottom electrode; 100. Third substrate; 110. Third bonding layer; 120. Fourth bonding layer; 130. Second bonding material layer; 140. Top electrode; 150. Cavity. Detailed Implementation

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0030] As mentioned in the background section, the electromechanical coupling coefficient K of a resonator directly affects the filtering bandwidth of the filter, while the quality factor Q directly affects the out-of-band rejection performance. Therefore, to obtain a resonator with better performance, high electromechanical coupling coefficient K and high quality factor Q are worth studying. In existing technologies, lithium niobate piezoelectric materials are typically used to fabricate resonators with high electromechanical coupling coefficients, and then the Q value of the resonator is improved through processing techniques and design. However, it is not possible to directly improve both the electromechanical coupling coefficient K and the quality factor Q value simultaneously using the piezoelectric material forming the resonator. Therefore, resonators in existing technologies struggle to achieve a high quality factor Q value while simultaneously improving the electromechanical coupling coefficient K.

[0031] To address the aforementioned technical problems, the inventors of this application provide a method for fabricating a resonator, comprising the following steps: providing a first substrate 10, wherein the first substrate 10 includes a first piezoelectric layer 20, such as... Figure 1 As shown; the first piezoelectric layer 20 has an exposed first surface; a first bonding layer 50 is formed on the first surface, the first bonding layer 50 having first piezoelectricity, so that the first bonding layer 50 covers the first surface, as shown. Figure 1 As shown; a second substrate 30 is provided, including a second bonding layer 60, the second substrate 30 having opposing first and second ends, the second bonding layer 60 being located at the second end, and the second bonding layer 60 having a second piezoelectricity, such as... Figure 2As shown; a damage layer 40 is formed in the second substrate 30 such that the damage layer 40 is located on the side of the first end close to the second bonding layer 60, and a portion of the second substrate 30 is between the damage layer 40 and the second bonding layer 60, as shown. Figure 2 As shown; the first bonding layer 50 and the second bonding layer 60 are bonded together to form a first wafer, and the first bonding layer 50 and the second bonding layer 60 constitute a first bonding material layer 70, as shown. Figure 3 As shown; the damaged layer 40 and the portion of the second substrate 30 away from the second bonding layer 60 are removed, and the remaining portion of the second substrate 30 forms a second piezoelectric layer 80. The second piezoelectric layer 80 has an exposed second surface. The first piezoelectric layer 20, the first bonding layer 50, the second bonding layer 60 (the first bonding layer 50 and the second bonding layer 60 constitute a first bonding material layer 70), and the second piezoelectric layer 80 constitute a composite piezoelectric layer. A bottom electrode 90 (e.g., ...) is sequentially formed on the second surface. Figure 4 (as shown) and supporting components, such as Figures 5 to 7 As shown, the third bonding layer 110, the fourth bonding layer 120, and the third substrate 100 constitute a support member. The bottom electrode 90 and a portion of the support member are alternately arranged. The support member is used to support the composite piezoelectric layer. The first substrate 10 is removed to expose the first piezoelectric layer 20. A top electrode 140 is formed on the side of the first piezoelectric layer 20 away from the second piezoelectric layer 80. Figures 8 to 9 As shown.

[0032] Using the above-described fabrication method, the first piezoelectric layer 20 and the second piezoelectric layer 80 can be bonded together to obtain a composite piezoelectric layer having the first piezoelectric layer 20 and the second piezoelectric layer 80. The first piezoelectric layer 20 in this composite piezoelectric layer can be used to improve the quality factor Q of the resonator, and the second piezoelectric layer 80 can be used to improve the electromechanical coupling coefficient K of the resonator. This combines the high-crystal-quality first piezoelectric layer 20 and the high-coupling-coefficient second piezoelectric layer 80, achieving the goal of improving the electromechanical coupling coefficient K of the resonator while improving the quality factor Q of the resonator. Furthermore, the piezoelectric characteristics of this composite piezoelectric layer are fully utilized and fed back to the performance of the resonator, thereby further improving the performance of the resonator and the filter containing it.

[0033] Exemplary embodiments of the method for fabricating a resonator according to the present invention will now be described in more detail. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art.

[0034] In some alternative implementations, such as Figure 2 As shown, the steps for forming the above-mentioned damage layer 40 include: forming the above-mentioned damage layer 40 by ion implantation.

[0035] In the above embodiment, by forming a damaged layer 40 using ion implantation, the second substrate 30 can be split through the damaged layer 40, thereby enabling a portion of the second substrate 30 to serve as the second piezoelectric layer in the composite piezoelectric layer. Specifically, the depth of the formed damaged layer 40 from the surface of the second bonding layer can be adjusted by adjusting the ion implantation process parameters. For example, the depth can be within 2 micrometers, thus using the substrate material within 2 micrometers of the exposed surface of the second bonding layer in the second substrate 30 as the subsequent second piezoelectric layer. For example, the ions implanted can be hydrogen (H) ions or helium (He) ions, and the ion implantation energy can be 1 keV to 1 MeV. The ion implantation angle is 0 to 60°, the ion implantation temperature is between 25 and 600°C, and the ion implantation dose is 1 × 10⁻⁶. 16 / cm 2 ~8×10 16 / cm 2 This is to allow the aforementioned damage layer 40 to be formed in the second substrate 30.

[0036] Specifically, the second substrate 30 has a first end and a second end, and the first end has the second bonding layer 60. By performing ion implantation on the second substrate 30, a damaged layer 40 is formed at the first end of the second substrate 30, making the damaged layer 40 close to the second bonding layer 60, and a portion of the second substrate 30 is located between the damaged layer 40 and the second bonding layer 60. This allows the portion of the second substrate 30 located between the damaged layer 40 and the second bonding layer 60 to be formed as a second piezoelectric layer in subsequent processes, such as... Figure 2 As shown, the material of the second substrate 30 further includes lithium niobate.

[0037] Among them, such as Figure 3 As shown in the figure, the dashed line represents the surface of the damaged layer 40. After the first bonding layer 50 and the second bonding layer 60 are bonded, in order to improve their bonding strength, a high-temperature annealing process can be used in some optional embodiments to make the bonding strength between the first bonding layer 50 and the second bonding layer 60 stronger, thereby forming a more stable first wafer. The first bonding layer 50 and the second bonding layer 60 constitute the first bonding material layer 70.

[0038] The first substrate 10 having the first piezoelectric layer 20 and the first bonding layer 50, and the second substrate 30 having the second bonding layer 60 are placed in a bonding machine under room temperature and atmospheric pressure conditions for bonding.

[0039] Directly bonding the first piezoelectric layer 20 and the first surface of the second substrate 30 can easily lead to problems such as thermal mismatch or lattice mismatch, thereby generating stress at the bonding interface. In order to relax the stress, certain dislocations will be formed at the interface, thus affecting the performance of the device.

[0040] Specifically, to solve the above-mentioned technical problems, in the above embodiment, a first bonding layer 50 is covered on the surface of the first piezoelectric layer 20 away from the first substrate 10, and a second bonding layer 60 is covered on the first surface of the second substrate 30, thereby bonding the first piezoelectric layer 20 and the first surface of the second substrate 30 together through the first bonding layer 50 and the second bonding layer 60 to form a first wafer. Since the first bonding layer 50 and the second bonding layer 60 are located between the first piezoelectric layer 20 and the second piezoelectric layer 80 in the first wafer, the first bonding layer 50 and the second bonding layer 60 can serve as bonds. The buffer layer allows the adverse effects of stress relaxation to be eliminated, thereby forming a high-quality first piezoelectric layer 20 and second piezoelectric layer 80. The first piezoelectric layer 20 is used to improve the quality factor Q of the resonator, and the second piezoelectric layer 80 is used to improve the electromechanical coupling coefficient K of the resonator. Furthermore, the first piezoelectric layer 20, which improves the quality factor Q, and the second piezoelectric layer 80, which improves the electromechanical coupling coefficient K, are better bonded together in the resonator. The material properties of the first piezoelectric layer 20 and the second piezoelectric layer 80 are basically unaffected after bonding, and they do not affect the performance of the device.

[0041] Furthermore, by setting the materials of the first bonding layer 50, the second bonding layer 60, and the first piezoelectric layer 20 to be the same, the bonding material can play both the role of bonding and its own piezoelectricity. This allows materials that improve the device quality factor Q value to be formed directly on the second substrate 30 without introducing other materials that affect device performance. For example, the materials of the first bonding layer 50 and the second bonding layer 60 can be aluminum nitride (AlN). Since the materials of the first bonding layer 50 and the second bonding layer 60 are the same as those of the first piezoelectric layer 20, the device process can be simplified and the cost reduced.

[0042] Furthermore, the first bonding layer 50 and the second bonding layer 60 can be formed by magnetron sputtering (physical vapor deposition). The reactants can be aluminum target (Al) and nitrogen (N2), and the first bonding layer 50 and the second bonding layer 60 can be generated in an environment with a temperature of 200°C to 500°C and a high vacuum pressure.

[0043] Before bonding the first piezoelectric layer 20 and the second substrate 30, a pre-annealing process may be included. Specifically, the first piezoelectric layer 20 may be placed at 300°C to 400°C in an N2 gas environment for 2 hours to densify the first piezoelectric layer 20 (including the AlN thin film), thereby helping to eliminate voids formed at the bonding interface and improve bonding quality. Then, the bonding surface can be rinsed with deionized water, dried after rinsing, and the side of the deposited first bonding layer 50 away from the first substrate 10 and the side of the deposited second bonding layer 60 away from the second piezoelectric layer 80 can be polished to improve the uniformity of the bonding surfaces of the first bonding layer 50 and the second bonding layer 60, forming a high-quality first wafer with uniform thickness. For example, the sum of the thicknesses of the first bonding layer 50 and the second bonding layer 60 is 10 nm to 100 nm. Figure 3 As shown.

[0044] Specifically, by setting the sum of the thicknesses of the first bonding layer 50 and the second bonding layer 60 to be between 10 nm and 100 nm, it can be ensured that the first piezoelectric layer 20 and the second piezoelectric layer 80 are bonded together through the first bonding layer 50 and the second bonding layer 60, without causing the device performance to be affected or materials to be wasted due to the increased thickness of the first bonding layer 50 and the second bonding layer 60.

[0045] In some alternative embodiments, the first wafer is heat-treated at a temperature of 300°C to 500°C under a nitrogen atmosphere.

[0046] In the above embodiment, after the step of forming the first wafer, since the first wafer also includes the portion of the second substrate 30 other than the second piezoelectric layer 80 required for the resonator, the first wafer is heat-treated so that the second substrate 30 can be split along the surface of the damaged layer 40 indicated by the dashed line. The remaining portion of the second substrate 30 connected to the first piezoelectric layer 20 forms the second piezoelectric layer 80, thereby removing the portion of the second substrate 30 other than the second piezoelectric layer 80 required for the resonator. This allows the remaining second piezoelectric layer 80, the first bonding material layer 70, and the first piezoelectric layer 20 in the first wafer to form a composite piezoelectric layer, such as... Figure 4 As shown.

[0047] Furthermore, a patterned bottom electrode 90 is formed on the side of the second piezoelectric layer 80 away from the first piezoelectric layer 20, such as... Figure 4As shown, since the bottom electrode 90, the first piezoelectric layer 20, the second piezoelectric layer 80, and the top electrode of the resonator constitute the effective operating region of the device, the device operates in an energy trapping-thickness vibration mode. Since the operating frequency of the resonator is inversely proportional to the thickness of the piezoelectric material, in order to achieve a higher operating frequency, the thickness of the piezoelectric material needs to be controlled. This is to avoid the device operating frequency being too low due to excessive thickness, resulting in poor device performance. Furthermore, due to the requirements of filter integration and miniaturization, directly using the target thickness for the second piezoelectric layer 80 and bonding it to the first piezoelectric layer 20 is difficult to achieve. Therefore, in the above embodiment, by employing a process method that first forms a damaged layer 40 in the second substrate 30, the target thickness of the desired second piezoelectric layer can be marked in the second substrate 30. This allows the second substrate 30 with the damaged layer 40 to retain a portion of the second substrate 30 located between the damaged layer 40 and the second bonding layer 60, and this portion of the second substrate 30 can be used as the second piezoelectric layer in the resonator. Furthermore, after forming the second piezoelectric layer 80 using this heat treatment method, since the split portion of the second substrate 30 is not needed for forming the resonator, it can be separately stored and reused multiple times. For example, the thickness of the second piezoelectric layer 80 can be less than or equal to 2 μm.

[0048] In some alternative embodiments, the first bonding layer 50, the second bonding layer 60, and the first piezoelectric layer 20 are made of the same material, wherein the materials of the first piezoelectric layer 20, the first bonding layer 50, and the second bonding layer 60 include at least aluminum nitride.

[0049] In the above embodiments, the material of the first piezoelectric layer 20 may include aluminum nitride. Since high-quality aluminum nitride material is difficult to grow on general seed layer material, in the above embodiments, the material of the first substrate 10 may be selected from any one of Si (111), sapphire, and silicon carbide (SiC) so that a high-quality first piezoelectric layer 20 (including aluminum nitride) can be formed on the first substrate 10.

[0050] In the above embodiments, in order to form a high-quality piezoelectric thin film structure by combining the first piezoelectric layer 20 and the second piezoelectric layer 80, materials with the same piezoelectric properties are used to bond the first piezoelectric layer 20 and the second piezoelectric layer 80. In order to avoid introducing more lattice mismatch, the materials of the first bonding layer 50 and the second bonding layer 60 are the same as those of the first piezoelectric layer 20. That is, in this embodiment, the materials of the first bonding layer 50, the second bonding layer 60 and the first piezoelectric layer are aluminum nitride. The AlN-AlN bonding of the first bonding layer 50 and the second bonding layer 60 is also an important part of forming a high-quality piezoelectric thin film. Furthermore, by annealing the first wafer at a temperature of 300°C to 500°C in a nitrogen atmosphere for 3 hours, the AlN-AlN bonding effect between the first bonding layer 50 and the second bonding layer 60 can be further strengthened. Since this temperature range is not too high, the second substrate 30 can be prevented from splitting due to the presence of the damage layer 40, so that the required second piezoelectric layer 80 is incomplete.

[0051] In some alternative embodiments, the step of forming the first piezoelectric layer 20 includes forming the first piezoelectric layer 20 on the surface of the first substrate 10 by chemical vapor deposition at a temperature of 1000°C to 1300°C and a pressure of 55 mbar to 500 mbar.

[0052] In the above embodiments, a metal-organic chemical vapor deposition method can be used to form the first piezoelectric layer 20 (including aluminum nitride) by reacting trimethylaluminum (TMAl) and ammonia (NH3) at a temperature of 1000°C to 1300°C and a pressure of 55 mbar to 500 mbar. Since the first bonding layer 50 and the second substrate 30 are bonded together to form a first bonding material layer 70, and the bonded second substrate 30 can also provide stress compensation for the first piezoelectric layer 20, under these conditions, a first piezoelectric layer 20 (including aluminum nitride) with excellent crystal quality can be grown to the maximum extent. Furthermore, the thickness of the first piezoelectric layer 20 (including aluminum nitride) can be between 30 nm and 1000 nm, thereby enabling the formed resonator to have good performance.

[0053] In some alternative embodiments, the step of forming the bottom electrode 90 and the support member includes: forming the bottom electrode 90 on the second surface of the second piezoelectric layer 80, such as... Figure 4 As shown; a third bonding layer 110 is formed in a portion of the second surface excluding the bottom electrode 90, with the bottom electrode 90 and the third bonding layer 110 alternating, as shown. Figure 5 As shown; a third substrate 100 is provided, and a fourth bonding layer 120 is formed on the third substrate 100, as follows. Figure 6 As shown; the third bonding layer 110 and the fourth bonding layer 120 are bonded together, as follows. Figure 7 As shown.

[0054] In the above embodiment, after forming the composite piezoelectric layer, a first electrode layer is first covered on the side of the second piezoelectric layer 80 away from the first piezoelectric layer 20, and the first electrode layer is etched to form a bottom electrode 90. Further, to support the composite piezoelectric layer, a third substrate 100 is provided, and a fourth bonding layer 120 on the third substrate 100 is bonded to a third bonding layer 110 on the side near the second piezoelectric layer 80, such that the third bonding layer 110 and the fourth bonding layer 120 constitute a second bonding material layer 130. Therefore, after removing the first substrate 10 located on the side of the first piezoelectric layer 20 away from the second piezoelectric layer 80, the third substrate 100 and the second bonding material layer 130 can support the composite piezoelectric layer. The first substrate 10 is removed by thinning or etching, thereby depositing a second electrode material on the side of the first piezoelectric layer 20 away from the second piezoelectric layer 80 in the composite piezoelectric layer, and etching the second electrode material to form a top electrode 140. In the direction perpendicular to the first substrate 10, the bottom electrode 90, the top electrode 140 and the composite piezoelectric layer have an overlapping region, so that the overlapping region serves as an effective region in the resonator to achieve normal operation of the resonator. It should be noted that the piezoelectric material layer located between the bottom electrode 90 and the top electrode 140 includes the first piezoelectric layer 20 after bonding, the first bonding material layer 70 and the second piezoelectric layer 80.

[0055] The first electrode material and the second electrode material can be selected from molybdenum (Mo), chromium (Cr), copper (Cu), platinum (Pt), gold (Au), aluminum (Al), titanium (Ti), etc., and the thickness of the bottom electrode 90 and the top electrode 140 can be set to 30-500 nm. The first electrode material and the second electrode material can be the same or different, and those skilled in the art can choose arbitrarily according to actual conditions.

[0056] Furthermore, to improve the bonding between the third substrate 100 and the composite piezoelectric layer, a third bonding layer 110 can be deposited first on the surface of the second piezoelectric layer 80 away from the first piezoelectric layer 20, such as... Figure 5 As shown, a fourth bonding layer 120 is deposited on the bonding surface of the third substrate 100, as follows: Figure 6 As shown, this allows the composite piezoelectric layer and the third substrate 100 to form a tight bonded connection through the third bonding layer 110 and the fourth bonding layer 120.

[0057] Optionally, the step of forming the third bonding layer 110 may involve first applying a patterned mask layer to cover photoresist on the composite piezoelectric layer having the bottom electrode 90, so that the photoresist covers the bottom electrode 90 and the exposed portions of the second piezoelectric layer 80 near both sides of the bottom electrode 90, while the portions of the second piezoelectric layer 80 away from the bottom electrode 90 are not covered by the photoresist. Then, a third bonding material is deposited on the side of the photoresist away from the first piezoelectric layer 20, so that the third bonding material covers the exposed second piezoelectric layer 80 and the photoresist. Finally, a stripping process is used to dissolve the photoresist, thereby... As the photoresist dissolves, a portion of the third bonding material covering the photoresist falls off the composite piezoelectric layer, thereby forming a third bonding layer 110 with the remaining portion of the third bonding material on the composite piezoelectric layer having the bottom electrode 90. The materials of the third bonding layer 110 and the fourth bonding layer 120 can be metal elements such as gold (Au), tin (Sn), and germanium (Ge). The sum of the thicknesses of the third bonding layer 110 and the fourth bonding layer 120 can be 300 to 2000 nm. The third bonding layer 110 and the fourth bonding layer 120 form a second bonding material layer 130.

[0058] In some alternative embodiments, the third bonding layer 110 and the bottom electrode 90 have a minimum spacing, which is greater than or equal to 10 μm, such as... Figure 7 As shown.

[0059] In the above embodiments, in order to better bond the third bonding layer 110 and the fourth bonding layer 120, and considering providing a certain space for the vibration of the thin film in the resonator, the minimum spacing between the third bonding layer 110 and the bottom electrode 90 is set to be more than 10 μm, so that the performance of the resonator is not affected.

[0060] According to another aspect of this application, the inventors also provide a resonator fabricated by the above-described method. This resonator includes the first piezoelectric layer 20, the second piezoelectric layer 80, and a first bonding material layer 70 that bonds the first piezoelectric layer 20 and the second piezoelectric layer 80 together. This allows the resonator to improve its quality factor Q through the first piezoelectric layer and its electromechanical coupling coefficient K through the second piezoelectric layer, further enhancing the performance of the resonator and any filters incorporating it.

[0061] like Figure 8As shown, in some optional embodiments, the resonator further includes: a third bonding layer 110 disposed on the side of the second piezoelectric layer 80 away from the first piezoelectric layer 20; a fourth bonding layer 120 disposed on the surface of the third substrate 100, and the fourth bonding layer 120 is bonded to the third bonding layer 110; and a cavity 150 disposed on the side of the bottom electrode 90 away from the top electrode 140, the cavity 150 being formed by the third bonding layer 110, the fourth bonding layer 120, the second piezoelectric layer 80, and the third substrate 100.

[0062] For example, a resonator includes: a first piezoelectric layer 20, the thickness of which can be 30 nm to 1000 nm; a second piezoelectric layer 80, having a first surface, disposed on the side of the first piezoelectric layer 20 away from the first substrate 10, and the first piezoelectric layer 20 is bonded to the first surface, wherein the materials of the first piezoelectric layer 20 and the second piezoelectric layer 80 are different; and a bottom electrode 90 disposed on a second surface of the second piezoelectric layer 80, the bottom electrode 90 being located on the side of the second piezoelectric layer 80 away from the first piezoelectric layer 20, the second surface being the surface of the second piezoelectric layer 80 opposite to the first surface. A third bonding layer 110 is disposed on the side of the second piezoelectric layer 80 away from the first piezoelectric layer 20; a fourth bonding layer 120 is disposed on the surface of the third substrate 100, and the fourth bonding layer 120 is bonded to the third bonding layer 110; the third bonding layer 110 and the bottom electrode 90 are located on the same horizontal plane; a top electrode 140 covers the surface of the first piezoelectric layer 20 away from the second piezoelectric layer 80; a cavity 150 is disposed on the side of the bottom electrode 90 away from the top electrode 140, and the cavity 150 is surrounded by the third bonding layer 110, the fourth bonding layer 120, the second piezoelectric layer 80 and the third substrate 100.

[0063] In some alternative embodiments, the resonator further includes: a third bonding layer 110 disposed on the side of the second piezoelectric layer 80 away from the first piezoelectric layer 20, and the third bonding layer 110 having a third surface in contact with the second piezoelectric layer 80, the second piezoelectric layer 80 completely covering the third surface; and a fourth bonding layer 120 disposed on the surface of the third substrate 100, and the fourth bonding layer 120 being bonded to the third bonding layer 110.

[0064] For example, such as Figure 9As shown, a resonator includes: a first piezoelectric layer 20, the thickness of which can be 30 nm to 1000 nm; a second piezoelectric layer 80, having a first surface, disposed on the side of the first piezoelectric layer 20 away from the first substrate 10, and the first piezoelectric layer 20 is bonded to the first surface, the materials of the first piezoelectric layer 20 and the second piezoelectric layer 80 being different; and a plurality of bottom electrodes 90, the bottom electrodes 90 being spaced apart on a second surface of the second piezoelectric layer 80, the bottom electrodes 90 being located on the side of the second piezoelectric layer 80 away from the first piezoelectric layer 20. The second surface is the surface of the second piezoelectric layer 80 opposite to the first surface; a third substrate 100; a third bonding layer 110, disposed on the side of the second piezoelectric layer 80 away from the first piezoelectric layer 20, and the third bonding layer 110 has a third surface in contact with the second piezoelectric layer 80, and the second piezoelectric layer 80 completely covers the third surface; a fourth bonding layer 120, disposed on the surface of the third substrate 100, and the fourth bonding layer 120 is bonded to the third bonding layer 110; a plurality of top electrodes 140, the top electrodes 140 being spaced apart on the side surface of the first piezoelectric layer 20 away from the second piezoelectric layer 80.

[0065] In the aforementioned resonator, since the first piezoelectric layer 20 and the second piezoelectric layer 80 formed by bonding are piezoelectric thin film layers in the device structure, and since the piezoelectric thin film layer is a composite piezoelectric layer, the first piezoelectric layer 20 in the composite piezoelectric layer can be used to improve the quality factor Q value of the resonator, and the second piezoelectric layer 80 can be used to improve the electromechanical coupling coefficient K of the resonator. Thus, the purpose of improving the quality factor Q value of the resonator is achieved at the same time as improving the electromechanical coupling coefficient K of the resonator, thereby further improving the performance of the resonator and the filter containing it.

[0066] The aforementioned composite piezoelectric layer can be applied to both thin-film bulk acoustic resonators (FBARs) and surface acoustic wave resonators (SAWs). Correspondingly, the fabrication method for forming the composite piezoelectric layer is applicable to both the method for forming the composite piezoelectric layer in FBARs and the method for forming the composite piezoelectric layer in SAWs.

[0067] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0068] By bonding the first and second piezoelectric layers together, a composite piezoelectric layer is formed in the resonator, thereby improving the internal structure of the piezoelectric layer. This allows the resonator with the composite piezoelectric layer to not only improve the quality factor Q through the first piezoelectric layer but also increase the electromechanical coupling coefficient K through the second piezoelectric layer. This further enhances the performance of the resonator and the filter containing it. Furthermore, since the composite piezoelectric layer is formed by directly bonding the first and second piezoelectric layers, it overcomes the problem in existing technologies where the first and second piezoelectric layers cannot be directly deposited to form the composite piezoelectric layer in the resonator, thus preventing the first and second piezoelectric layers from functioning simultaneously. This achieves the goal of improving the resonator's performance.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for manufacturing a resonator, characterized in that, The manufacturing method includes: A first substrate is provided, the first substrate including a first piezoelectric layer having an exposed first surface; A first bonding layer is formed on the first surface, the first bonding layer having a first piezoelectricity, so that the first bonding layer covers the first surface; A second substrate is provided, including a second bonding layer, the second substrate having opposing first and second ends, the second bonding layer being located at the second end, and the second bonding layer having a second piezoelectricity; A damage layer is formed in the second substrate such that the damage layer is located on the side of the first end close to the second bonding layer, and a portion of the second substrate is between the damage layer and the second bonding layer; The first bonding layer and the second bonding layer are bonded together to form a first wafer; The damaged layer and a portion of the second substrate away from the second bonding layer are removed, and the remaining portion of the second substrate forms a second piezoelectric layer. The second piezoelectric layer has an exposed second surface. The first piezoelectric layer, the first bonding layer, the second bonding layer, and the second piezoelectric layer constitute a composite piezoelectric layer. A bottom electrode and a support member are sequentially formed on the second surface, wherein the bottom electrode and a portion of the support member are alternately arranged, and the support member is used to support the composite piezoelectric layer; Remove the first substrate to expose the first piezoelectric layer; A top electrode is formed on the side of the first piezoelectric layer away from the second piezoelectric layer.

2. The manufacturing method according to claim 1, characterized in that, The steps for forming the damaged layer include: The damaged layer was formed using ion implantation.

3. The manufacturing method according to claim 1, characterized in that, The first wafer was heat-treated at a temperature of 300℃ to 500℃ under a nitrogen atmosphere.

4. The manufacturing method according to any one of claims 1 to 3, characterized in that, The first bonding layer, the second bonding layer, and the first piezoelectric layer are made of the same material, wherein the materials of the first piezoelectric layer, the first bonding layer, and the second bonding layer include at least aluminum nitride.

5. The manufacturing method according to any one of claims 1 to 3, characterized in that, The steps for forming the first piezoelectric layer include: The first piezoelectric layer is formed on the surface of the first substrate by chemical vapor deposition at a temperature of 1000℃ to 1300℃ and a pressure of 55mbar to 500mbar.

6. The manufacturing method according to claim 1, characterized in that, The steps of forming the bottom electrode and the support member include: A bottom electrode is formed on the second surface of the second piezoelectric layer; A third bonding layer is formed in a portion of the second surface excluding the bottom electrode, and the bottom electrode and the third bonding layer are alternately disposed; A third substrate is provided, and a fourth bonding layer is formed on the third substrate; The third bonding layer and the fourth bonding layer are bonded together.

7. The manufacturing method according to claim 6, characterized in that, The third bonding layer has a minimum spacing with respect to the bottom electrode, and the minimum spacing is greater than or equal to 10 μm.

8. A resonator, manufactured by the method of any one of claims 1 to 7.

9. The resonator according to claim 8, characterized in that, The resonator also includes: The third bonding layer is disposed on the side of the second piezoelectric layer away from the first piezoelectric layer; A fourth bonding layer is disposed on the surface of the third substrate, and the fourth bonding layer is bonded to the third bonding layer; A cavity is disposed on the side of the bottom electrode away from the top electrode, and the cavity is surrounded by the third bonding layer, the fourth bonding layer, the second piezoelectric layer and the third substrate.

10. The resonator according to claim 8, characterized in that, The resonator also includes: A third bonding layer is disposed on the side of the second piezoelectric layer away from the first piezoelectric layer, and the third bonding layer has a third surface in contact with the second piezoelectric layer, the second piezoelectric layer completely covering the third surface; A fourth bonding layer is disposed on the surface of the third substrate, and the fourth bonding layer is bonded to the third bonding layer.

Images