Low-noise elastic wave device and manufacturing method therefor

Abstract

The technical subject of the present invention relates to a low-noise elastic wave device and a manufacturing method therefor, the device comprising: a piezoelectric substrate; input side electrodes and output side electrodes formed on the piezoelectric substrate; and a support substrate bonded to the piezoelectric substrate, wherein at least one groove is formed in a partial area of the support substrate, preventing noise-inducing waves from propagating toward the output side.

Description

Low-noise elastic wave device and its manufacturing method

[0001] The present invention relates to an elastic wave element and a method for manufacturing the same, and more particularly, to a low-noise elastic wave element that reduces noise by forming a groove in the elastic wave element and a method for manufacturing the same.

[0002] The national research and development projects that supported this invention are as follows.

[0003] Assignment ID 1711173218

[0004] Assignment number 2022M3H4A3051764

[0005] Ministry of Science and ICT

[0006] Project Management Institution Name: National Research Foundation of Korea

[0007] Research Project Name: Nanomaterial Technology Development

[0008] Research Project Title: Development of 6-inch LiTaO3 on Si heterojunction wafers for high-frequency filters

[0009] Contribution rate 1 / 2

[0010] Name of the project performing organization: Korea Institute of Nanotechnology

[0011] Research Period: April 8, 2022 - December 31, 2024

[0012] Assignment ID 1711154893

[0013] Assignment number 2020M3H4A3081731

[0014] Ministry of Science and ICT

[0015] Project Management Institution Name: National Research Foundation of Korea

[0016] Research Project Name: Nanomaterial Technology Development

[0017] Research Project Name: Development of superlattice application semiconductor material growth technology using organic metal vapor phase growth.

[0018] Contribution rate 1 / 2

[0019] Name of the project performing organization: Korea Institute of Nanotechnology

[0020] Research period: May 15, 2020 - December 31, 2024

[0021] Elastic wave devices using piezoelectric materials include surface acoustic wave (SAW) devices and film bulk acoustic resonators (FBAR).

[0022] In general, elastic wave elements include a piezoelectric substrate on which metal electrodes (Interdigital Transducers (IDTs)) are formed. When an electric signal is applied to one metal electrode, an elastic surface wave is generated on the surface of the piezoelectric substrate. When the elastic surface wave reaches the other metal electrode, it is converted back into an electric signal. Since the propagation loss is small, it can be miniaturized, and it can be manufactured in a semiconductor manufacturing process, it can be manufactured at a low cost, and it is widely used as a bandpass filter in communication devices such as mobile phones.

[0023] In order to improve the performance of these elastic wave elements, a technology is being studied to bond a support substrate different from the piezoelectric substrate to the piezoelectric substrate in order to minimize physical changes in the piezoelectric substrate due to temperature and reduce frequency fluctuations.

[0024] In particular, the support substrate has a smaller coefficient of thermal expansion than the piezoelectric substrate, and by bonding it to the piezoelectric substrate, physical changes in the piezoelectric substrate due to temperature changes are minimized, and changes in frequency characteristics are suppressed.

[0025] Meanwhile, in elastic wave devices, DBAW (Deep Bulk Acoustic Wave), SSBW (Surface Skimming Bulk Wave), and LBAW (Leaked Bulk Acoustic Wave) are causes of noise, so a method to reduce loss by removing spurious noise is required.

[0026] To reduce such losses, a heterojunction SAW element structure is required that uses a thin piezoelectric substrate and requires substrate bonding using the above-described support substrate to support the thin piezoelectric substrate.

[0027] However, in the case of a thin piezoelectric substrate, there is a problem of increased electrical parasitic components (R, C). That is, as the thickness of the piezoelectric substrate becomes thinner, the supporting substrate becomes closer to the metal electrode, so C (Ca pacitance) increases, and thus the resistance influence of the supporting substrate increases. Therefore, in order to reduce this, a large resistance of the supporting substrate is required.

[0028] In order to reduce the influence of resistance by such a support substrate and to increase the resistance of the support substrate, there is a prior art technique (US 10,574,203) that adds an insulating layer between the piezoelectric substrate and the support substrate, or adds (implantation) a resistor to the surface of the support substrate. However, since adding an insulating layer is a method that increases the overall impedance by reducing capacitance, it only has the effect of lowering the influence of resistance, and implantation that adds resistance directly increases the resistance of the surface of the support substrate, but the resistance under the surface remains the same, so it is difficult to eliminate the influence of low impedance due to parasitic components.

[0029] The present invention was derived from the above-mentioned necessity, and its purpose is to provide a low-noise elastic wave element and a method for manufacturing the same, which reduces noise by forming a groove in the elastic wave element to prevent the propagation of waves from the input side to the output side to a part other than the surface of the piezoelectric substrate.

[0030] In order to achieve the above object, the present invention provides a low-noise elastic wave device comprising a piezoelectric substrate, input-side electrodes and output-side electrodes formed on the piezoelectric substrate, and a support substrate bonded to the piezoelectric substrate, wherein at least one groove is formed in a portion of the support substrate to prevent propagation of waves causing noise to the output side.

[0031] In addition, the present invention is another technical point of a low-noise elastic wave element comprising a piezoelectric substrate, and an input-side electrode and an output-side electrode formed on the piezoelectric substrate, wherein at least one groove is formed in a portion of the piezoelectric substrate, and the groove is formed in a bridge portion between the input side and the output side or in the bridge portion and the output side, thereby preventing propagation of waves that cause noise to the output side.

[0032] In addition, the present invention provides a low-noise elastic wave device comprising a piezoelectric substrate, input-side electrodes and output-side electrodes formed on the piezoelectric substrate, and a support substrate bonded to the piezoelectric substrate, wherein at least one continuous groove is formed in a portion of the piezoelectric substrate and the support substrate, and the groove is formed in a bridge portion between the input side and the output side or in the bridge portion and the output side to prevent propagation of waves that cause noise to the output side, as another technical point.

[0033] In addition, the present invention is another technical summary of a method for manufacturing an elastic wave element, which comprises the steps of forming a piezoelectric substrate, forming an input-side electrode and an output-side electrode on the piezoelectric substrate, and bonding a support substrate to the piezoelectric substrate, wherein at least one groove is formed in a portion of the support substrate, or at least one groove is formed continuously in a portion of the support substrate and the piezoelectric substrate, thereby preventing propagation of waves that cause noise to the output side.

[0034] Additionally, the groove may be formed on the input side, or on the input side and the output side, or on the bridge portion between the input side and the output side, or on the bridge portion and the output side.

[0035] Additionally, a protective film may be formed on the piezoelectric substrate, input-side electrode, and output-side electrode. Additionally, an upper frequency control layer may be formed on the protective film, and a surface protective film may be formed on the upper frequency control layer.

[0036] Additionally, a composite insulating layer including a lower frequency control layer may be formed between the piezoelectric substrate and the support substrate. Additionally, it is preferable that the composite insulating layer have a structure of insulating layer / lower frequency control layer or an insulating layer / lower frequency control layer / insulating layer.

[0037] Additionally, it is preferable that a groove be formed in a portion of the composite insulating layer in continuity with the groove formed on the input side of the support substrate.

[0038] Additionally, it is preferable that a composite insulating layer including a lower frequency control layer be formed between the piezoelectric substrate and the support substrate.

[0039] In addition, it is preferable that the composite insulating layer has a structure of insulating layer / lower frequency control layer or an insulating layer / lower frequency control layer / insulating layer.

[0040] Additionally, it is preferable that a groove be formed in a portion of the composite insulating layer in continuity with the groove formed on the input side of the support substrate.

[0041] In addition, it is preferable that the groove is in the form of a cavity within the device, either in a form that is open to the outside of the support substrate or in a form that is open to the inside of the support substrate.

[0042] In addition, it is preferable that the low-noise elastic wave element further has a heat dissipation layer formed on the support substrate side.

[0043] The present invention aims to minimize loss and reduce output noise by preventing the propagation of waves that cause noise from being transmitted from the input side to the output side to a part other than the surface of the piezoelectric substrate.

[0044] In particular, the present invention forms a groove on a support substrate of a heterojunction elastic wave element, thereby eliminating the influence of the resistance of the support substrate, thereby eliminating loss due to eddy current, and also eliminating the influence of parasitic resistance and parasitic capacitor.

[0045] In addition, the present invention forms a groove in a support substrate of a heterojunction elastic wave element, so that the support substrate provides a heat dissipation path and can minimize spurious noise by absorbing or reflecting unnecessary high-order mode BAW, etc.

[0046] In addition, the present invention forms a groove in a piezoelectric substrate to remove BAW and the like that propagates to the output side, thereby eliminating spurious noise.

[0047] In addition, the present invention forms a groove in a piezoelectric substrate or a support substrate, thereby alleviating edge cracks occurring in a conventional CMP (Chemical Mechanical Polishing) process, thereby improving throughput in the CMP process.

[0048] FIGS. 1 to 41 - Schematic diagrams of low-noise elastic wave devices according to various embodiments of the present invention.

[0049] The present invention relates to a structure for reducing noise of an elastic wave element and a manufacturing method thereof, and aims to minimize loss and reduce output noise by preventing the propagation of waves that cause noise from being transmitted from the input side to the output side to a part other than the surface of a piezoelectric substrate.

[0050] In particular, the present invention forms a groove on a support substrate of a heterojunction elastic wave element, thereby eliminating the influence of the resistance of the support substrate, thereby eliminating loss due to eddy current, and also eliminating the influence of parasitic resistance and parasitic capacitor, and minimizing spurious noise.

[0051] In addition, the present invention forms a groove on a support substrate, thereby alleviating edge cracks that occur in a conventional CMP (Chemical Mechanical Polishing) process, thereby improving throughput in the CMP process.

[0052] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings. Figures 1 to 41 illustrate schematic diagrams of low-noise elastic wave elements according to various embodiments of the present invention.

[0053] As illustrated in FIGS. 1 and 2, a low-noise elastic wave element according to an embodiment of the present invention comprises a piezoelectric substrate (100), an input-side electrode (220) and an output-side electrode (240) formed on the piezoelectric substrate (100), and a support substrate (300) bonded to the piezoelectric substrate (100), wherein at least one groove (400) is formed in a portion of the support substrate (300) to prevent propagation of waves that cause noise to the output side.

[0054] The support substrate (300) in the present invention may be any type of substrate that has different physical or chemical properties from the piezoelectric substrate (100) and thus offsets or increases the physical or chemical effects.

[0055] In one embodiment of the present invention, a silicon substrate is used as a support substrate (300) for implementing a bonding structure of heterogeneous substrates suitable for a surface acoustic wave (SAW) device, and LiTaO3, LiNbO3, InP, GaAs, Ge, AlN, GaP, InAs, InSb, AlSb, Ba2NaNb5O5, Pb2KNb5O is used as a piezoelectric substrate (100). 15 , PZT, CIGS, etc. substrates can be used. In particular, LiTaO3 and LiNbO3 are widely used as piezoelectric substrates (100) and are used as substrate materials for SAW (Surface Acoustic Wave) filter elements. For convenience, the silicon substrate may also be referred to as a silicon wafer.

[0056] Here, since the coefficient of thermal expansion of the silicon substrate is lower than that of the piezoelectric substrate (100), by bonding it to the piezoelectric substrate (100), physical changes in the piezoelectric substrate (100) due to temperature changes are minimized, and changes in frequency characteristics are suppressed.

[0057] The present invention forms a groove (400) in some area of ​​such a bonding structure, preferably in a support substrate (300), or in the support substrate (300) and the piezoelectric substrate (100), thereby forming an area in which the resistance is infinite in the support substrate (300), and preventing noise sources from propagating to the output side.

[0058] In particular, the groove (400) is formed on the support substrate (300) of the input side or the input side and the output side of the elastic wave element, or on the support substrate (300) and the piezoelectric substrate (100), to remove a noise source by removing a wave that propagates from the input side to the output side other than the surface. That is, by reflecting unintended sources of output signals such as DBAW, SSBW, and Leaked BAW that cause noise at the interface of the piezoelectric substrate (100) and preventing them from propagating to the output side, spurious noise is removed, thereby reducing output noise.

[0059] In addition, by forming a groove on the support substrate (300), the resistance on the support substrate (300) side is made infinite, thereby reducing loss due to eddy current, eliminating the influence of parasitic resistance and parasitic capacitance, and eliminating spurious noise.

[0060] According to one embodiment of the present invention, the thickness t of the piezoelectric substrate in the groove area is t≥SAW Penetration Depth (penetration thickness, Xc), and the thickness t must be thicker than the penetration thickness Xc, and the penetration thickness Xc decreases as the frequency increases and thickens as the speed increases. According to one embodiment of the present invention, the thickness of the piezoelectric substrate in the groove area can be adjusted according to the frequency and speed, and is preferably 1 to 10 μm.

[0061] In addition, the elastic wave element according to one embodiment of the present invention forms a protective film (520) on the piezoelectric substrate (100), the input side electrode (220), and the output side electrode (240) to protect the piezoelectric substrate (100) and the electrodes. The protective film (520) is used as an insulating material. For example, SiO2, Si-LiNbO3, Si-LiTaO3, Si-InP, Si-GaAs, Si-Ge SiO2, Si-LiNbO3, Si-LiTaO3, Si-InP, Si-GaAs, Si-Ge, Si-AlN, Si-GaP, Si-InAs, Si-InSb, Si-AlSb, Si-Ba2NaNb5O5, Si-Pb2KNb5O15 , Si-PZT, Si-CIGS can be formed by laminating one or more of them in multiple layers.

[0062] In addition, in an elastic wave element according to one embodiment of the present invention, an upper frequency control layer (540) may be formed on the protective film (520), and a surface protection film (560) may be further formed on the upper frequency control layer (540).

[0063] The above protective film (520) and surface protective film (560) may be formed of the same material or different materials, and both are formed of an insulating material.

[0064] The upper frequency control layer (540) uses a material having a higher elastic velocity than the material of the protective film (520), and the protective film (520) is formed on the upper and lower sides to control the spurious shear horizontal mode frequency on the upper side of the piezoelectric substrate (100), and to reduce noise in the passband of the filter by reducing discontinuity in the impedance parameter curve.

[0065] The upper frequency control layer (540) according to one embodiment of the present invention may use Si3N4, AlN, Al2O3, etc.

[0066] In addition, according to one embodiment of the present invention, a composite insulating layer including a lower frequency control layer (640) may be further formed between the piezoelectric substrate (100) and the support substrate (300).

[0067] The above composite insulating layer may have a structure of insulating layer (620) / lower frequency control layer (640) or a structure of insulating layer (620) / lower frequency control layer (640) / insulating layer (660), and multiple insulating layers may be laminated as needed.

[0068] That is, the elastic element according to the embodiment of the present invention has a structure of surface passivation film (560) / upper frequency control layer (540) / passivation film (520) / piezoelectric substrate (100) / insulating layer (620) / lower frequency control layer (640) / supporting substrate (300) or surface passivation film (560) / upper frequency control layer (540) / passivation film (520) / piezoelectric substrate (100) / insulating layer (620) / lower frequency control layer (640) / insulating layer (660) / supporting substrate (300), or passivation film (520) / piezoelectric substrate (100) / insulating layer (620) / lower frequency control layer (640) / supporting substrate (300) or passivation film (520) / piezoelectric substrate (100) / insulating layer (620) / lower frequency control layer (640) / supporting substrate (300) It may have a structure of a frequency control layer (640) / insulating layer (660) / support substrate (300).

[0069] The above insulating layers (620), (660) can be formed of the same or similar material as the above-described protective film (520), and the insulating layers (620), (660) are formed on the upper and lower sides of the frequency control layer, thereby controlling the spurious shear horizontal mode frequency on the lower side of the piezoelectric substrate (100) and reducing the discontinuity in the impedance parameter curve, thereby reducing noise in the passband of the filter.

[0070] The lower frequency control layer (640) according to one embodiment of the present invention may use Si3N4, AlN, Al2O3, etc., similarly to the upper frequency control layer (540), and as described above, the frequency control layer may be formed on either or both of the upper or lower portions of the piezoelectric substrate (100).

[0071] Here, as an embodiment of the present invention, a groove (400) may be formed in a portion of the composite insulating layer in continuity with the groove (400) formed on the input side of the support substrate (300), thereby reducing loss due to eddy current by making the resistance on the support substrate (300) side infinite, eliminating the influence of parasitic resistance and parasitic capacitance, and eliminating spurious noise. In addition, since a composite insulating layer including a lower frequency control layer (640) is formed on the output side, it is possible to control the spurious front-end horizontal mode frequency and reduce discontinuity in the impedance parameter curve, thereby reducing noise in the passband of the filter.

[0072] In addition, the groove (400) according to one embodiment of the present invention may be in the form of a cavity within the device, either in a form that is open to the outside of the support substrate (300) or in a form that is open to the inside of the support substrate (300). When formed in a cavity, it is advantageous in terms of heat dissipation and mechanical strength, and is advantageous in maintaining the TCF (Temperature Coefficient of Frequency).

[0073] These grooves (400) can be formed in a single shape or a continuous pattern, and can be formed in a regular or irregular pattern. The shape of the grooves (400) is appropriately selected and applied considering heat dissipation, mechanical strength, and TCF aspects.

[0074] In addition, the elastic wave element according to one embodiment of the present invention further has a heat dissipation layer (700) formed toward the support substrate (300), thereby making heat dissipation more advantageous.

[0075] Thus, the present invention relates to a structure for reducing noise of an elastic wave element, and aims to minimize loss and reduce output noise by preventing the propagation of waves that cause noise from being transmitted from the input side to the output side to a part other than the surface of the piezoelectric substrate (100).

[0076] In particular, the present invention forms a groove (400) in the support substrate (300) of a heterojunction elastic wave element, thereby eliminating the influence of the resistance of the support substrate (300), thereby eliminating loss due to eddy current, and also eliminating the influence of parasitic resistance and parasitic capacitor. In addition, the present invention forms a groove (400) in the support substrate (300) of a heterojunction elastic wave element, thereby enabling the support substrate (300) to provide a heat dissipation path, and to minimize spurious noise by absorbing or reflecting unnecessary high-order mode BAW, etc.

[0077] In addition, the present invention forms a groove (400) on a support substrate (300), thereby alleviating edge cracks occurring in a conventional CMP process, thereby improving throughput in the CMP process.

[0078] In addition, as another embodiment of the present invention, it can be applied to a single substrate elastic wave element without bonding of a support substrate (300), and in an elastic wave element including a piezoelectric substrate (100) and an input side electrode (220) and an output side electrode (240) formed on the piezoelectric substrate (100), at least one groove (400) is formed in a portion of the piezoelectric substrate (100), and the groove (400) is formed in a bridge portion between the input side and the output side or in the bridge portion and the output side, thereby preventing propagation of waves that cause noise to the output side.

[0079] In addition, a protective film (520) may be formed on the piezoelectric substrate (100), the input side electrode (220), and the output side electrode (240), and further, an upper frequency control layer (540) may be formed on the protective film (520), and a surface protective film (560) may be formed on the upper frequency control layer (540).

[0080] This eliminates spurious noise by preventing noise sources from propagating to the output side, controls the spurious shear horizontal mode frequency by the upper frequency control layer (540), and reduces noise in the passband of the filter by reducing discontinuity in the impedance parameter curve.

[0081] In addition, as another embodiment of the present invention, in an elastic wave element including a piezoelectric substrate (100), an input-side electrode (220) and an output-side electrode (240) formed on the piezoelectric substrate (100), and a support substrate (300) bonded to the piezoelectric substrate (100), at least one continuous groove (400) is formed in a portion of the piezoelectric substrate (100) and the support substrate (300), and the groove (400) is formed in a bridge portion between the input side and the output side or in the bridge portion and the output side to prevent propagation of waves that cause noise to the output side.

[0082] In addition, as an embodiment of the present invention, a protective film (520) may be formed on the piezoelectric substrate (100), the input side electrode (220), and the output side electrode (240), an upper frequency control layer (540) may be formed on the protective film (520), and a surface protective film (560) may be formed on the upper frequency control layer (540).

[0083] In addition, a composite insulating layer including a lower frequency control layer (640) may be formed between the piezoelectric substrate (100) and the support substrate (300), and the composite insulating layer may have a structure of insulating layer (620) / lower frequency control layer (640) or may be formed with a structure of insulating layer (620) / lower frequency control layer (640) / insulating layer (660).

[0084] The groove (400) according to this embodiment of the present invention may be in the form of a cavity within the device, either in a form that is open to the outside of the support substrate (300) or in a form that is open to the inside of the support substrate (300).

[0085] In addition, in the low-noise elastic wave element according to one embodiment of the present invention, a heat dissipation layer (700) may be further formed toward the support substrate (300).

[0086] In this way, the present invention aims to minimize loss and reduce output noise by preventing the propagation of waves that cause noise from being propagated from the input side to the output side to a part other than the surface of the piezoelectric substrate (100).

[0087] In addition, the present invention forms a groove (400) in a support substrate (300) of a heterojunction elastic wave element, so that the support substrate (300) provides a heat dissipation path and can minimize spurious noise by absorbing or reflecting unnecessary high-order mode BAW, etc.

[0088] In addition, the present invention forms a groove (400) on a support substrate (300), thereby alleviating edge cracks occurring in a conventional CMP process, thereby improving throughput in the CMP process.

[0089] Hereinafter, an embodiment of the present invention will be summarized and described again with reference to the attached drawings.

[0090] FIG. 1, FIG. 2 and FIG. 3 illustrate an elastic wave element including a piezoelectric substrate (100), an input-side electrode (220) and an output-side electrode (240) formed on the piezoelectric substrate (100), and a support substrate (300) bonded to the piezoelectric substrate (100), wherein one or more grooves (400) are formed in a portion of the support substrate (300).

[0091] FIG. 1 illustrates that a single-shaped groove (400) is formed on the input side of a support substrate (300), FIG. 2 illustrates that a single-shaped groove (400) is formed on the input side and the output side of a support substrate (300), and FIG. 3 illustrates that one or more grooves (400) are formed on the input side and the output side of a support substrate (300).

[0092] Accordingly, the present invention forms a groove (400) on the support substrate (300) of a heterojunction elastic wave element, thereby eliminating the influence of the resistance of the support substrate (300), thereby eliminating loss due to eddy current, and also eliminating the influence of parasitic resistance and parasitic capacitor. In addition, the support substrate (300) provides a heat dissipation path, and can minimize spurious noise by absorbing or reflecting unnecessary high-order mode BAW, etc.

[0093] In addition, the present invention forms a groove (400) on a support substrate (300), thereby alleviating edge cracks occurring in a conventional CMP process, thereby improving throughput in the CMP process.

[0094] In addition, the groove (400) according to the present invention may be formed in one or more forms, either in a single shape or in a continuous pattern, and may be formed in a regular or irregular pattern. The shape of the groove (400) is appropriately selected and applied in consideration of heat dissipation, mechanical strength, and TCF aspects.

[0095] FIG. 4 and FIG. 5 illustrate that a protective film (520) is formed on the piezoelectric substrate (100), the input side electrode (220), and the output side electrode (240) in the above embodiment. FIG. 4 illustrates that a groove (400) is formed on the input side of the support substrate (300), and FIG. 5 illustrates that a groove (400) is formed on the input side and the output side of the support substrate (300).

[0096] FIG. 6 and FIG. 7 illustrate that in the above embodiment, an upper frequency control layer (540) is formed on the protective film (520) and a surface protective film (560) is formed on the upper frequency control layer (540). FIG. 6 illustrates that a groove (400) is formed on the input side of the support substrate (300), and FIG. 7 illustrates that a groove (400) is formed on the input side and the output side of the support substrate (300).

[0097] FIG. 8 and FIG. 9 illustrate that a composite insulating layer including a lower frequency control layer (640) is formed between the piezoelectric substrate (100) and the support substrate (300) in the above embodiment. In this embodiment, the composite insulating layer has a structure of an insulating layer (620) / lower frequency control layer (640) / insulating layer (660).

[0098] That is, an upper frequency control layer (540) structure is formed on the upper side of the piezoelectric substrate (100), and a lower frequency control layer (640) structure is formed on the lower side of the piezoelectric substrate (100).

[0099] Fig. 8 shows that a groove (400) is formed on the input side of the support substrate (300), and Fig. 9 shows that a groove (400) is formed on the input side and the output side of the support substrate (300).

[0100] By controlling the spurious shear horizontal mode frequency through the upper and lower frequency control layers (640), the noise in the passband of the filter can be reduced by reducing the discontinuity in the impedance parameter curve.

[0101] FIG. 10 and FIG. 11 illustrate that a groove (400) is formed in a portion of the composite insulating layer in a manner that is continuous with the groove (400) formed on the input side of the support substrate (300) in the above embodiment. FIG. 10 illustrates that a continuous groove (400) is formed on the input side of the support substrate (300) and the composite insulating layer, and FIG. 11 illustrates that a continuous groove (400) is formed on the input side of the support substrate (300) and the composite insulating layer, and a groove (400) is formed only on the support substrate (300) on the output side, so that the composite insulating layer structure including the lower frequency control layer (640) on the output side is maintained.

[0102] FIG. 12, FIG. 13, and FIG. 14 illustrate that a protective film (520) is formed, and a composite insulating layer including a lower frequency control layer (640) is formed between a piezoelectric substrate (100) and a support substrate (300). In this embodiment, the composite insulating layer has a structure of an insulating layer (620) / lower frequency control layer (640) / insulating layer (660). FIG. 12 shows a case where a continuous groove (400) is formed on the input side of the support substrate (300) and the composite insulating layer, FIG. 13 shows a case where one or more continuous grooves (400) are formed on the input side of the support substrate (300) and the composite insulating layer, and FIG. 14 shows a case where a continuous groove (400) is formed on the input side of the support substrate (300) and the composite insulating layer, and a groove (400) is formed only on the support substrate (300) on the output side, so that the composite insulating layer structure including the lower frequency control layer (640) on the output side is maintained.

[0103] FIG. 15, FIG. 16, FIG. 17, and FIG. 18 illustrate an elastic wave element having an upper frequency control layer (540) structure and a lower frequency control layer (640) structure (composite insulating layer), wherein the groove (400) is formed in a form that is open toward the inside of the support substrate (300) to form a cavity within the element. The embodiments of FIG. 1 to FIG. 14 described above have the groove (400) formed in a form that is open toward the outside of the support substrate (300).

[0104] FIG. 15 shows a case where a continuous groove (400) is formed in a hollow shape on the input side of a support substrate (300) and a composite insulating layer, FIG. 16 shows a case where one or more grooves (400) are formed in the shape of an embodiment of FIG. 15, FIG. 17 shows a case where a continuous groove (400) is formed in a hollow shape on the input side of a support substrate (300) and a composite insulating layer, and has an upper high-speed side structure and a lower frequency control layer (640) structure (composite insulating layer), and FIG. 18 shows a case where one or more grooves (400) are formed in the shape of an embodiment of FIG. 17.

[0105] According to an embodiment of the present invention, when the groove (400) is opened toward the inside of the support substrate (300) to form a cavity, it is advantageous in terms of heat dissipation and mechanical strength, and is advantageous in maintaining TCF.

[0106] FIG. 19, FIG. 20, FIG. 21, and FIG. 22 illustrate that a support substrate (300) is formed on a piezoelectric substrate (100), and that continuous grooves (400) are formed on the input side or the input side and the output side of the piezoelectric substrate (100) and the support substrate (300). FIG. 19 illustrates that a groove (400) is formed on the input side of the piezoelectric substrate (100) and the support substrate (300), and FIG. 20 illustrates that a continuous groove (400) is formed on the input side and the output side of the piezoelectric substrate (100) and the support substrate (300), and FIG. 21 and FIG. 22 illustrate that a protective film (520) is formed on the piezoelectric substrate (100), the input side electrode (220), and the output side electrode (240), respectively, in the embodiments of FIG. 19 and FIG. 20.

[0107] Figures 23 and 24 illustrate cases in which an upper frequency control layer (540) and a surface protective film (560) are formed in the embodiments of Figures 21 and 22, respectively.

[0108] Fig. 25 illustrates that a groove (400) is formed in the bridge portion between the input side and the output side of the piezoelectric substrate (100), and Fig. 26 illustrates that a groove (400) is formed continuously in the bridge portion between the input side and the output side of the piezoelectric substrate (100) and the output side.

[0109] According to one embodiment of the present invention, a groove (400) is formed in a piezoelectric substrate (100) to remove BAW, etc. that are transmitted to the output side, thereby eliminating spurious noise.

[0110] FIG. 27 and FIG. 28 illustrate that a protective film (520) is formed in FIG. 25 and FIG. 26, respectively, and FIG. 29 and FIG. 30 illustrate that an upper frequency control layer (540) and a surface protective film (560) are formed in the embodiment of FIG. 27 and FIG. 28, respectively.

[0111] FIG. 31 illustrates a bonding structure of a piezoelectric substrate (100) and a support substrate (300), in which a groove (400) is formed continuously in the piezoelectric substrate (100) and the support substrate (300) in the bridge portion between the input side and the output side, and FIG. 32 illustrates that the groove (400) is formed up to the output side including the bridge portion.

[0112] Fig. 33 shows the embodiment of Fig. 31 with a further protective film (520) formed, and Fig. 34 shows the embodiment of Fig. 32 with a further protective film (520) formed.

[0113] FIG. 35 shows the upper frequency control layer (540) and the surface protection film (560) formed in the embodiment of FIG. 33, and FIG. 36 shows the upper frequency control layer (540) and the surface protection film (560) formed in the embodiment of FIG. 34.

[0114] Fig. 37 illustrates that a lower frequency control layer (640) structure (composite insulating layer) is formed between a piezoelectric substrate (100) and a support substrate (300), and that a groove (400) is formed in the bridge portion of the support substrate (300). Fig. 38 illustrates that a groove (400) is formed in the bridge portion of the support substrate (300) when an upper frequency control layer (540) structure is formed in the embodiment of Fig. 37.

[0115] Figures 39 and 40 illustrate that one or more grooves (400) are formed in the bridge portion of the piezoelectric substrate (100) or the bridge portion of the piezoelectric substrate (100) and the support substrate (300). This is to maintain the mechanical strength by adjusting the mechanical ratio of the substrate while also maintaining the TCF.

[0116] Fig. 41 shows that in the embodiment of Fig. 33, a heat dissipation layer (700) is further formed toward the support substrate (300), thereby making heat dissipation more advantageous.

[0117] Meanwhile, a method for manufacturing a low-noise elastic wave element according to an embodiment of the present invention includes a process of forming a piezoelectric substrate (100), forming an input-side electrode (220) and an output-side electrode (240) on the piezoelectric substrate (100), and bonding a support substrate (300) to the piezoelectric substrate (100), wherein at least one groove (400) is formed in a portion of the support substrate (300), or at least one groove (400) is continuously formed in a portion of the support substrate (300) and the piezoelectric substrate (100), thereby preventing propagation of waves that cause noise to the output side.

[0118] The above groove (400) can be implemented by an etching process according to a patterning process of the support substrate (300).

[0119] The above groove (400) is formed on the input side, or the input side and the output side, or the bridge portion between the input side and the output side, or the bridge portion and the output side.

[0120] In addition, a protective film (520) is formed on the piezoelectric substrate (100), the input side electrode (220), and the output side electrode (240), an upper frequency control layer (540) is formed on the protective film (520), and a surface protective film (560) is formed on the upper frequency control layer (540).

[0121] In addition, after forming a composite insulating layer including a lower frequency control layer (640) on the support substrate (300), it is bonded to the piezoelectric substrate (100), thereby forming a composite insulating layer between the piezoelectric substrate (100) and the support substrate (300). In addition, the composite insulating layer is formed to have a structure of an insulating layer (620) / lower frequency control layer (640) or a structure of an insulating layer (620) / lower frequency control layer (640) / insulating layer (660).

[0122] In addition, a groove (400) may be formed in a portion of the composite insulating layer continuously with the groove (400) formed in the support substrate (300). In this case, in the patterning process for forming the groove (400) of the support substrate (300), the support substrate (300) and the composite insulating layer may be etched simultaneously to form a continuous groove (400) in the support substrate (300) and the composite insulating layer.

[0123] In addition, the insulating layer (620), (660) can be formed with a quantized thickness corresponding to an integer multiple of the minimum unit thickness in the growth direction on the support substrate (300).

[0124] In addition, the insulating layers (620) and (660) can be deposited by a CVD method for a total process time that is an integer multiple of the unit process time corresponding to the minimum unit thickness and the no-growth time. This thickness control leads to a uniform thickness and maintains surface roughness.

[0125] The insulating layers 620 and 660 include SiO2, Si-LiNbO3, Si-LiTaO3, Si-InP, Si-GaAs, Si-Ge SiO2, Si-LiNbO3, Si-LiTaO3, Si-InP, Si-GaAs, Si-Ge, Si-AlN, Si-GaP, Si-InAs, Si-InSb, Si-AlSb, Si-Ba2NaNb5O5, Si-Pb2KNb5O 15 , Si-PZT, Si-CIGS, or one or more materials can be formed as multilayers.

[0126] Additionally, a groove (400) can be formed in a portion of the composite insulating layer in a manner that is continuous with the groove (400) formed in the support substrate (300).

[0127] In addition, the low-noise elastic wave element according to one embodiment of the present invention can further form a heat dissipation layer (700) toward the support substrate (300).

[0128] Thus, the present invention relates to a structure for reducing noise of an elastic wave element and a manufacturing method thereof, and aims to minimize loss and reduce output noise by preventing the propagation of waves that cause noise from being transmitted from the input side to the output side to a part other than the surface of the piezoelectric substrate.

[0129] In particular, the present invention forms a groove on a support substrate of a heterojunction elastic wave element, thereby eliminating the influence of the resistance of the support substrate, thereby eliminating loss due to eddy current, and also eliminating the influence of parasitic resistance and parasitic capacitor.

[0130] In addition, the present invention forms a groove in a support substrate of a heterojunction elastic wave element, so that the support substrate provides a heat dissipation path and can minimize spurious noise by absorbing or reflecting unnecessary high-order mode BAW, etc.

[0131] In addition, the present invention forms a groove in a piezoelectric substrate to remove BAW and the like that propagates to the output side, thereby eliminating spurious noise.

[0132] In addition, the present invention forms a groove on a support substrate, thereby alleviating edge cracks that occur in a conventional CMP process, thereby improving throughput in the CMP process.

Claims

1. In an elastic wave element including a piezoelectric substrate, input-side electrodes and output-side electrodes formed on the piezoelectric substrate, and a support substrate bonded to the piezoelectric substrate, One or more grooves are formed in some area of ​​the above support substrate, A low-noise elastic wave device characterized by preventing propagation of waves that cause noise to the output side.

2. In the first paragraph, the groove, Input side or, A low-noise elastic wave element characterized by being formed on the support substrate on the input side and the output side.

3. A low-noise elastic wave element characterized in that a protective film is formed on the piezoelectric substrate, input-side electrode, and output-side electrode in the second paragraph.

4. In the third paragraph, an upper frequency control layer is formed on the protective film, A low-noise elastic wave device characterized in that a surface protective film is formed on the upper frequency control layer.

5. A low-noise elastic wave element characterized in that a composite insulating layer including a lower frequency control layer is formed between the piezoelectric substrate and the support substrate in the fourth paragraph.

6. In paragraph 5, the composite insulating layer, It has the structure of an insulation layer / lower frequency control layer, or A low-noise elastic wave device characterized by having a structure of an insulating layer / lower frequency control layer / insulating layer.

7. A low-noise elastic wave element characterized in that, in the fifth paragraph, a groove is formed in a portion of the composite insulating layer in continuity with the groove formed on the input side of the support substrate.

8. A low-noise elastic wave element characterized in that a composite insulating layer including a lower frequency control layer is formed between the piezoelectric substrate and the support substrate in the third paragraph.

9. In paragraph 8, the composite insulating layer, It has the structure of an insulation layer / lower frequency control layer, or A low-noise elastic wave element characterized by having a structure of an insulating layer / lower frequency control layer / insulating layer.

10. A low-noise elastic wave element characterized in that, in the 8th paragraph, a groove is formed in a portion of the composite insulating layer in continuity with the groove formed on the input side of the support substrate.

11. A low-noise elastic wave element characterized in that a groove is formed in a portion of the piezoelectric substrate in a manner continuous with the groove formed in the support substrate in the first paragraph.

12. In the 11th paragraph, the groove, Input side or, A low-noise elastic wave element characterized by being formed on the support substrate and piezoelectric substrate on the input side and the output side.

13. A low-noise elastic wave element according to claim 12, characterized in that a protective film is formed on the piezoelectric substrate, the input-side electrode, and the output-side electrode.

14. In the 13th paragraph, an upper frequency control layer is formed on the protective film, A low-noise elastic wave device characterized in that a surface protective film is formed on the upper frequency control layer.

15. A low-noise elastic wave element characterized in that a composite insulating layer including a lower frequency control layer is formed between the piezoelectric substrate and the support substrate in the 14th paragraph.

16. In paragraph 15, the composite insulating layer, It has the structure of an insulation layer / lower frequency control layer, or Low noise characterized by having a structure of insulating layer / lower frequency control layer / insulating layer 17. A low-noise elastic wave element characterized in that, in claim 14, a groove is formed in a portion of the composite insulating layer in continuity with the groove formed on the input side of the support substrate.

18. A low-noise elastic wave element characterized in that a composite insulating layer including a lower frequency control layer is formed between the piezoelectric substrate and the support substrate in the 13th paragraph.

19. In paragraph 18, the composite insulating layer, It has the structure of an insulation layer / lower frequency control layer, or A low-noise elastic wave element characterized by having a structure of an insulating layer / lower frequency control layer / insulating layer.

20. A low-noise elastic wave element characterized in that, in claim 18, a groove is formed in a portion of the composite insulating layer in continuity with the groove formed on the input side of the support substrate.

21. In any one of paragraphs 1 to 20, the groove is or an open form on the outside of the above support substrate, A low-noise elastic wave device characterized by having a cavity shape within the device in an open form toward the inside of the above-mentioned support substrate.

22. In paragraph 21, the low-noise elastic wave element, A low-noise elastic wave element characterized in that a heat dissipation layer is further formed on the support substrate side.

23. In an elastic wave element including a piezoelectric substrate and an input-side electrode and an output-side electrode formed on the piezoelectric substrate, One or more grooves are formed in some areas of the above piezoelectric substrate, The above groove is, Bridge section between input side and output side or Formed on the above bridge section and output side, A low-noise elastic wave device characterized by preventing propagation of waves that cause noise to the output side.

24. A low-noise elastic wave element according to claim 23, characterized in that a protective film is formed on the piezoelectric substrate, the input-side electrode, and the output-side electrode.

25. In the 24th paragraph, an upper frequency control layer is formed on the protective film, A low-noise elastic wave device characterized in that a surface protective film is formed on the upper frequency control layer.

26. In an elastic wave element including a piezoelectric substrate, input-side electrodes and output-side electrodes formed on the piezoelectric substrate, and a support substrate bonded to the piezoelectric substrate, One or more continuous grooves are formed in a portion of the piezoelectric substrate and the support substrate, The above groove is, Bridge section between input side and output side or Formed on the above bridge section and output side, A low-noise elastic wave device characterized by preventing propagation of waves that cause noise to the output side.

27. A low-noise elastic wave element according to claim 26, characterized in that a protective film is formed on the piezoelectric substrate, the input-side electrode, and the output-side electrode.

28. In paragraph 27, an upper frequency control layer is formed on the protective film, A low-noise elastic wave device characterized in that a surface protective film is formed on the upper frequency control layer.

29. A low-noise elastic wave element characterized in that a composite insulating layer including a lower frequency control layer is formed between the piezoelectric substrate and the support substrate in claim 28.

30. In paragraph 29, the composite insulating layer, It has the structure of an insulation layer / lower frequency control layer, or A low-noise elastic wave device characterized by having a structure of an insulating layer / lower frequency control layer / insulating layer.

31. A low-noise elastic wave element characterized in that a composite insulating layer including a lower frequency control layer is formed between the piezoelectric substrate and the support substrate in claim 28.

32. In paragraph 31, the composite insulating layer, It has the structure of an insulation layer / lower frequency control layer, or A low-noise elastic wave element characterized by having a structure of an insulating layer / lower frequency control layer / insulating layer.

33. In any one of paragraphs 26 to 32, the groove is: or an open form on the outside of the above support substrate, A low-noise elastic wave device characterized by having a cavity shape within the device in an open form toward the inside of the above-mentioned support substrate.

34. In paragraph 33, the low-noise elastic wave element, A low-noise elastic wave element characterized in that a heat dissipation layer is further formed on the support substrate side.

35. A method for manufacturing an elastic wave element, comprising the steps of forming a piezoelectric substrate, forming an input-side electrode and an output-side electrode on the piezoelectric substrate, and bonding a support substrate to the piezoelectric substrate. Forming one or more grooves in some area of ​​the above support substrate, or By forming one or more grooves continuously in a part of the above support substrate and the above piezoelectric substrate, A method for manufacturing a low-noise elastic wave element characterized by preventing propagation of waves that cause noise to the output side.

36. In paragraph 35, the groove, Input side or, Input side and output side or, Bridge section between input side and output side or A method for manufacturing a low-noise elastic wave element characterized by forming the bridge section and the output side.

37. A method for manufacturing a low-noise elastic wave element, characterized in that a protective film is formed on the piezoelectric substrate, input-side electrode, and output-side electrode in claim 35.

38. In paragraph 37, an upper frequency control layer is formed on the protective film, A method for manufacturing a low-noise elastic wave element, characterized by forming a surface protective film on the upper frequency control layer.

39. A method for manufacturing a low-noise elastic wave element, characterized in that in claim 38, a composite insulating layer including a lower frequency control layer is formed on the support substrate, and then the composite insulating layer is bonded to the piezoelectric substrate to form a composite insulating layer between the piezoelectric substrate and the support substrate.

40. In paragraph 38, the composite insulating layer, It has the structure of an insulation layer / lower frequency control layer, or A method for manufacturing a low-noise elastic wave element characterized by having a structure of an insulating layer / lower frequency control layer / insulating layer.

41. In paragraph 40, the insulating layer is A method for manufacturing a low-noise elastic wave element, characterized in that the element is formed with a quantized thickness corresponding to an integer multiple of the minimum unit thickness in the growth direction on the above-mentioned support substrate.

42. In paragraph 41, the insulating layer is A method for manufacturing a low-noise elastic wave element characterized in that the element is deposited by a CVD method for a total process time that is an integer multiple of the unit process time corresponding to the minimum unit thickness and the sum of the no-growth time.

43. A method for manufacturing a low-noise elastic wave element, characterized in that, in claim 39, a groove is formed in a portion of the composite insulating layer in a manner continuous with the groove formed in the support substrate.

44. A method for manufacturing a low-noise elastic wave element, characterized in that, in claim 37, a composite insulating layer including a lower frequency control layer is formed on the support substrate, and then the composite insulating layer is bonded to the piezoelectric substrate to form a composite insulating layer between the piezoelectric substrate and the support substrate.

45. In paragraph 44, the composite insulating layer, It has the structure of an insulation layer / lower frequency control layer, or A method for manufacturing a low-noise elastic wave element characterized by having a structure of an insulating layer / lower frequency control layer / insulating layer.

46. ​​In paragraph 45, the insulating layer is A method for manufacturing a low-noise elastic wave element, characterized in that the element is formed with a quantized thickness corresponding to an integer multiple of the minimum unit thickness in the growth direction on the above-mentioned support substrate.

47. In paragraph 46, the insulating layer is A method for manufacturing a low-noise elastic wave element characterized in that the element is deposited by a CVD method for a total process time that is an integer multiple of the unit process time corresponding to the minimum unit thickness and the sum of the no-growth time.

48. A method for manufacturing a low-noise elastic wave element, characterized in that in claim 44, a groove is formed in a portion of the composite insulating layer in a manner that is continuous with the groove formed in the support substrate.

49. In any one of paragraphs 35 to 48, the low-noise elastic wave element, A method for manufacturing a low-noise elastic wave element, characterized in that a heat dissipation layer is further formed on the support substrate side.

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