Surface acoustic wave filter with connected plunger

Abstract

The present invention relates to a surface acoustic wave filter with connected plungers, and more particularly, to a surface acoustic wave filter. The surface acoustic wave filter having connected plungers includes, on a substrate in which a support substrate, an energy limiting layer, and a piezoelectric layer are laminated in this order: an I-DT electrode portion in which a first bus bar and a second bus bar extending in a first direction and extending in a second direction, and a plurality of first I-DT electrodes and second I-DT electrodes extending in a third direction and extending in a fourth direction are formed, the I-DT electrode portion being formed on a substrate in which the support substrate, the energy limiting layer, and the piezoelectric layer are laminated in this order; a plurality of first and second busbars and spaced apart from each other in a second direction perpendicular to the first direction, the plurality of first and second I DT electrodes alternately extending in the second direction from the first and second busbars and spaced apart in the first direction, respectively; and a lower plunger and an upper plunger formed in a strip shape extending in the first direction so as to cover front ends of the plurality of first and second IDT electrodes, the upper plunger and the lower plunger being connected by a plunger connection portion in a region other than the IDT electrode portion.

Description

Technical Field

[0001] The present invention relates to a surface acoustic wave filter having a connected bar piston, and more particularly to a surface acoustic wave filter in which a bar piston is formed to suppress spurious components generated by a transverse mode, and in order to prevent defects from occurring in the manufacturing process of the bar piston, disconnected bar pistons are connected to each other, thereby improving productivity and defect incidence. Background Art

[0002] Surface acoustic wave (SAW) refers to a wave that propagates along the surface of an elastic solid. The energy of this elastic surface wave is concentrated and propagated near the surface, and is equivalent to a mechanical wave. Surface acoustic wave elements are electromechanical elements that utilize the interaction between surface acoustic waves and semiconductor conductive electrons, and utilize surface acoustic waves conducted on the surface of piezoelectric crystals. This type of surface acoustic wave element can have a very wide range of applications in industries such as sensors, oscillators, and filters, and can be miniaturized and lightweight, and has many advantages such as robustness, stability, sensitivity, low cost, and real-time performance.

[0003] However, unnecessary transverse modes of the surface acoustic wave filter may generate spurious components and increase insertion loss, which adversely affects performance. In order to reduce the side effects caused by such transverse modes, a method has been proposed to reduce the propagation speed of the surface acoustic wave by forming an edge portion with a low speed on the IDT electrode.

[0004] The applicant has also developed a surface acoustic wave resonator that realizes the edge portion as a low-frequency region. The surface acoustic wave filter can be formed with one or more surface acoustic wave resonators. It can be composed of one surface acoustic wave resonator 110 to form a single-band surface acoustic wave filter 10, or multiple surface acoustic wave resonators 110 can be connected in parallel to form a multi-band surface acoustic wave filter 10.

[0005] Figure 1 This is a diagram of a surface acoustic wave resonator having a mass-added film formed in a dotted shape. Figure 2 is based on Figure 1 A cross-sectional view of the AA' section of the surface acoustic wave resonator.

[0006] Reference Figure 1 and Figure 2 A first bus bar 120 and a second bus bar 125 extending along a first direction and spaced apart from each other along a second direction perpendicular to the first direction are formed on a substrate 100 in which a support substrate, an energy confinement layer and a piezoelectric layer are sequentially stacked.

[0007] Next, a plurality of first IDT electrodes 130 and second IDT electrodes 135 are formed, which are alternately extended from the first bus bar 120 and the second bus bar 125 in the second direction and are spaced apart from each other in the first direction.

[0008] A pair of reflectors 180A and 180B are provided along the first direction on both sides of the first IDT electrode 130 or the second IDT electrode 135 on the substrate 100. The first IDT electrode 130, the second IDT electrode 135, and the reflectors 180A and 180B may be formed of a metal film.

[0009] In the region where the first IDT electrode 130 and the second IDT electrode 135 overlap, both ends of the center portion form edge portions having a sound velocity lower than that of the center portion.

[0010] Reference Figure 1 The area marking on the left side shows that the area corresponding to C2 or C3 represents the edge part, and the area corresponding to C1 represents the center part. The sound speed of the area corresponding to C2 or C3 is formed to be lower than the sound speed of the area C1.

[0011] Reference Figure 1 and Figure 2 In order to realize the C2 or C3 region as a low-speed region, a dot-shaped mass addition film 160 is formed on the C2 or C3 region of the IDT electrode.

[0012] By adding the dot-shaped mass addition films 160 to the edge portions C2 and C3 , the sound velocity of the edge portions C2 and C3 is lowered than the sound velocity of the IDT electrode center portion C1 .

[0013] However, as described above, when the mass adding film 160 is formed by adding a dot-shaped electrode, short circuit between the IDT electrodes 130 and 135 must be avoided, so the width of the dot-shaped mass adding film 160 must be equal to or smaller than the width of the IDT electrodes 130 and 135. In addition, considering the overlay error of the photolithography process, the design size can only be realized smaller.

[0014] For example, since the width of a general IDT electrode of a 2 GHz band surface acoustic wave resonator is 0.5 μm or less, the width of the dot-shaped electrode should be 0.4 μm or less. Since the width of the dot-shaped mass addition film 160 is the smallest among the elements constituting the surface acoustic wave resonator 110, the dot-shaped mass addition film 160 smaller than the width of the IDT electrodes 130 and 135 is formed in close contact with the IDT electrodes 130 and 135 without displacement, which is the most difficult process in the manufacture of the surface acoustic wave filter.

[0015] If the dot-shaped mass addition film 160 is displaced to the left and right due to a manufacturing process variation and is separated from the IDT electrodes 130 and 135 , the desired stray component suppression function cannot be normally performed, resulting in a performance defect of the surface acoustic wave filter.

[0016] In order to overcome these shortcomings, the applicant has developed a method of using a Figure 3 The method shown is to form a plug with long strips of dielectric rather than dots to achieve a low-speed mode.

[0017] Figure 3 is a diagram of a surface acoustic wave resonator formed with a plunger, Figure 4 is based on Figure 3 The cross-sectional view of the AA' section of the surface acoustic wave resonator, Figure 5 is based on Figure 3 Cross-sectional view of the BB' section of a surface acoustic wave resonator.

[0018] Reference Figures 3 to 5 The first and second bus bars 120 and 125 , the first and second IDT electrodes 130 and 135 , and the reflectors 180A and 180B included in the surface acoustic wave resonator 110 are formed similarly to those described in the surface acoustic wave resonator 110 including the dot-shaped mass addition film 160 .

[0019] In the region where the first IDT electrode 130 and the second IDT electrode 135 overlap, both ends of the center portion form edge portions having a sound velocity lower than that of the center portion.

[0020] Reference Figure 3 The area markings on the left side indicate that the area corresponding to C2 or C3 represents the edge portion, and the area corresponding to C1 represents the center portion. The sound speed of the area corresponding to C2 or C3 is lower than the sound speed of the area C1.

[0021] Reference Figures 3 to 5 In order to realize the area of ​​C2 or C3 as a low-speed area, the plunger 162 can cross the plurality of first IDT electrodes 130 and second IDT electrodes 135 and extend in an integral form. The plunger 162 crosses the plurality of IDT electrodes 130 and 135 and completely fills the area between the plurality of electrodes to form a strip shape. In this way, the piston mode is realized by using a bar-shaped dielectric, so it is called a plunger (bar piston) 162.

[0022] The plugs 162 are added to the edge portions C2 and C3 so that the sound velocity of the edge portions C2 and C3 is lower than the sound velocity of the IDT electrode center portion C1.

[0023] Since the strip-shaped plug 162 is made of dielectric material, there is no concern that the IDT electrodes 130 and 135 are short-circuited. In addition, since the strip-shaped plug 162 is continuously formed along the first direction, there is no need to consider the overlay error in the first direction during the photolithography process.

[0024] Figure 6 As plan views of a substrate of a surface acoustic wave filter having a plug, (a) shows a substrate formed by arranging a plurality of surface acoustic wave resonators, and (b) is a view of a photoresist mask for forming the plug on the substrate.

[0025] The thickness of the general plunger 162 is about 0.55λ when the period of the IDT electrode is λ. In the case of a SAW filter with a resonance frequency of 2 GHz, the period λ is about 1.5 um, and the thickness of the plunger is about 0.8 um. Figure 6 In FIG. 1 , the thickness of the plunger 162 is shown exaggerated for ease of illustration.

[0026] To form the strip-shaped plug 162, a lift-off process is used. Figure 7 is a diagram showing the stripping process, referring to Figure 7 , the formation process of the plunger 162 is described.

[0027] First, refer to Figure 7 (a) , a photoresist 190 is coated on the substrate 100 formed with the IDT electrodes 130 and 135. The photoresist 190 is removed by masking and exposure process, so that the dielectric 164 can be deposited only on the plug 162.

[0028] Secondly, refer to Figure 7 (b), a dielectric 164 forming a plug 162 is deposited on the front surface of the substrate 100 .

[0029] In addition, refer to Figure 7 (c) In order to peel off the photoresist 190 from the substrate 100, the substrate 100 is immersed in a resist stripping liquid 191, and the resist stripping liquid 191 penetrates into the gap between the photoresist 190 and the dielectric 164, so that the photoresist 190 can be removed.

[0030] When the photoresist 190 is completely removed, the IDT electrodes 130 and 135 are formed with the same Figure 7 (d) Dielectric pattern of the same shape.

[0031] However, if Figure 6 As shown in (b), a plug that is strip-shaped, narrow and long, and separated like an island is difficult to form by a stripping process. This is because a narrow strip is left to form the plug 162, and a large area of ​​photoresist 190 around the plug 162 must be stripped.

[0032] In addition, when the photoresist 190 is peeled off, it may be removed in very large chunks, thereby damaging the IDT electrodes 130 and 135 of the surface acoustic wave resonator 110 , thereby deteriorating the performance of the surface acoustic wave filter.

[0033] It is necessary to improve the difficulty of the lift-off process performed to form such a plug and the defects generated in the above process. Summary of the invention

[0034] The technical problem to be solved by the present invention is to provide a surface acoustic wave filter which can prevent damage to an IDT electrode in a process of forming a plug added to suppress stray components caused by a transverse mode.

[0035] The technical problems of the present invention are not limited to the technical problems mentioned above, and those skilled in the art can clearly understand other technical problems not mentioned from the following description.

[0036] In order to solve the above-mentioned technical problems, the surface acoustic wave filter with connected plugs of the present invention is characterized in that it may include, on a substrate on which a supporting substrate, an energy limiting layer and a piezoelectric layer are stacked in sequence: an IDT electrode portion, which is formed with a first bus and a second bus and a plurality of first IDT electrodes and a second IDT electrode, wherein the first bus and the second bus are extended along a first direction and are separated from each other along a second direction perpendicular to the first direction, and the plurality of first IDT electrodes and second IDT electrodes are extended alternately from the first bus and the second bus along the second direction and are separated respectively along the first direction; a lower plug and an upper plug, which are formed into a strip extending along the first direction so as to cover the front ends of the plurality of first IDT electrodes and the second IDT electrodes, and the upper plug and the lower plug are connected by a plug connecting portion in an area other than the IDT electrode portion.

[0037] In some embodiments of the present invention, reflectors may be further included, which are formed on both sides of the IDT electrode portion along the first direction.

[0038] In some embodiments of the present invention, the plunger connection may be characterized as being formed on the exterior of the reflector.

[0039] In some embodiments of the present invention, the plunger connection may be characterized as being formed through the exterior and interior of the reflector.

[0040] In some embodiments of the present invention, the plunger connection may be characterized by including a disconnection zone.

[0041] In some embodiments of the present invention, the plunger connection may be characterized by including a curved section.

[0042] In some embodiments of the present invention, the plunger connection portion may be characterized by a non-constant thickness.

[0043] In order to solve the above technical problems, the manufacturing method of the surface acoustic wave filter of the present invention is characterized in that it may include the following steps: forming an IDT electrode portion on a substrate on which a supporting substrate, an energy limiting layer and a piezoelectric layer are stacked in sequence, which includes a first bus and a second bus and a plurality of first IDT electrodes and a second IDT electrode, wherein the first bus and the second bus extend along a first direction and are separated from each other along a second direction perpendicular to the first direction, and the plurality of first IDT electrodes and second IDT electrodes extend alternately from the first bus and the second bus along the second direction and are separated respectively along the first direction; and forming a strip-shaped lower plug and an upper plug extending along the first direction so as to cover the front ends of the plurality of first IDT electrodes and the second IDT electrodes, and the upper plug and the lower plug are connected by a plug connecting portion in an area other than the IDT electrode portion.

[0044] In order to solve the above technical problems, the surface acoustic wave filter manufacturing method of the present invention is characterized in that it may include the following steps: simultaneously forming a plurality of surface acoustic wave resonators including an IDT electrode portion on a substrate on which a supporting substrate, an energy confinement layer and a piezoelectric layer are sequentially stacked, wherein the IDT electrode portion includes a first bus and a second bus and a plurality of first IDT electrodes and a second IDT electrode, wherein the first bus and the second bus are extended along a first direction and are spaced apart from each other along a second direction perpendicular to the first direction, and the plurality of first IDT electrodes and the second IDT electrodes are alternately extended from the first bus and the second bus along the second direction and are spaced apart from each other along the first direction; and forming a strip-shaped lower plug and an upper plug extending along the first direction so as to cover the front ends of the plurality of first IDT electrodes and the second IDT electrodes, wherein the plurality of surface acoustic wave resonators are connected in parallel, and the plugs are connected by a plug connection portion in an area other than the IDT electrode portion.

[0045] In some embodiments of the present invention, the plunger may be characterized in that the plunger connecting portion is formed by extending to the outer contour of the surface acoustic wave resonator.

[0046] In some embodiments of the present invention, the plunger may be characterized in that the plunger connecting portion is formed by connecting the surface acoustic wave resonator.

[0047] In some embodiments of the present invention, the plunger connection portion may be characterized in that it is formed by extending to the outer contour of the substrate.

[0048] According to the surface acoustic wave filter with connected plugs of the present invention, the plugs are added to the area other than the IDT electrode portion and connected. In the stripping process for forming the plugs, the operation can be performed quickly and easily, especially by reducing the block to be stripped to prevent damage to the IDT electrode. In this way, when manufacturing the surface acoustic wave filter, the productivity can be improved by increasing the process speed and preventing defects from occurring. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a diagram of a surface acoustic wave resonator having a dot-shaped mass-added film.

[0050] Figure 2 is based on Figure 1 A cross-sectional view of the AA' section of the surface acoustic wave resonator.

[0051] Figure 3 FIG. 1 is a diagram of a surface acoustic wave resonator formed with a plunger.

[0052] Figure 4 is based on Figure 3 A cross-sectional view of the AA' section of the surface acoustic wave resonator.

[0053] Figure 5 is based on Figure 3 Cross-sectional view of the BB' section of a surface acoustic wave resonator.

[0054] Figure 6 It is a plan view of a substrate of a surface acoustic wave filter having a plunger.

[0055] Figure 7 is a diagram showing a lift-off process.

[0056] Figure 8 is a diagram of a surface acoustic wave resonator according to an embodiment of the present invention.

[0057] Fig. 9 is a plan view of a substrate of a surface acoustic wave filter according to an embodiment of the present invention.

[0058] Fig.10 : is a diagram showing a connection example of a plunger according to one embodiment of the present invention.

[0059] Fig.11 is a plan view of a substrate including a plug connection in a surface acoustic wave filter according to an embodiment of the present invention.

[0060] Fig.12 FIG. 1 is a diagram showing connection of plungers in adjacent surface acoustic wave filters according to an embodiment of the present invention.

[0061] Description of symbols

[0062] 10: Surface acoustic wave filter

[0063] 100: Substrate

[0064] 110: Surface Acoustic Wave Resonator

[0065] 120: First bus

[0066] 121: First pseudo electrode

[0067] 125: Second bus

[0068] 126: Second pseudo electrode

[0069] 130: First IDT electrode

[0070] 135: Second IDT electrode

[0071] 150: IDT Electrode Department

[0072] 160: Quality additional film

[0073] 162: Plunger

[0074] 163: Plunger connection

[0075] 164: Dielectric

[0076] 180A, 180B: Reflector

[0077] 190: Photoresist

[0078] 191: Resist stripping liquid DETAILED DESCRIPTION

[0079] The advantages, features, and methods of achieving the same of the present invention will become clear when referring to the accompanying drawings and the embodiments described in detail below. However, the present invention is not limited to the embodiments disclosed below, but is implemented in different and diverse forms. This embodiment is only provided to ensure that the disclosure of the present invention is complete and to fully inform the scope of the invention to those with general knowledge in the technical field to which the present invention belongs. The present invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals represent the same constituent elements.

[0080] “And / or” includes each and all combinations of more than one of the mentioned items.

[0081] The terms used in this specification are used to illustrate the embodiments and are not intended to limit the present invention. In this specification, the singular also includes the plural, unless otherwise specified in a sentence. The use of "comprising" and / or "comprising..." in the specification to refer to constituent elements, steps, actions and / or elements does not exclude the existence or addition of one or more other constituent elements, steps, actions and / or elements.

[0082] In addition, throughout the specification, when a certain part is “connected” to another part, it includes not only the case of “direct connection” but also the case of “indirect connection” or “electrical connection” with other parts or elements interposed therebetween.

[0083] In addition, throughout the specification, the description that each layer (film), region, pattern or structure is formed "on" or "under" a substrate, each side (film), region, pad or pattern includes being formed directly or with other layers intervening. The reference of the upper / upper or lower / underside of each layer is described with reference to the accompanying drawings.

[0084] In addition, expressions such as "first, second", etc. are merely expressions used to distinguish between a plurality of components, and do not limit the order or other characteristics between the components.

[0085] Unless otherwise defined, any term (including technical terms and scientific terms) used in this specification can be used as the meaning commonly understood by people with general knowledge in the technical field to which the present invention belongs. In addition, the terms defined in the commonly used dictionaries will not be ideally or excessively interpreted unless there is an obvious special definition.

[0086] The present invention will be described in detail with reference to the accompanying drawings. Figure 8 1 is a diagram of a surface acoustic wave resonator according to an embodiment of the present invention, wherein (a) is a case without a dummy electrode, and (b) is a case with a dummy electrode.

[0087] Reference Figure 8 The surface acoustic wave resonator 110 according to one embodiment of the present invention may include a substrate 100, a first bus bar 120, a second bus bar 125, a plurality of first IDT electrodes 130, a second IDT electrode 135, reflectors 180A and 180B, a plug 162, and a plug connection portion 163. Dummy electrodes 121 and 126 may also be included.

[0088] The substrate 100 may be a multilayer substrate including a plurality of layers. The plurality of layers may include, for example, a support substrate including silicon, a high-speed membrane including a substance such as amorphous silicon (a-Si) or polycrystalline silicon, a low-speed membrane including silicon oxide (SiO2), and a piezoelectric layer located at the upper portion of the low-speed membrane, i.e., the uppermost portion, including a substance such as LiTaO3 (LT), LiNbO3 (LN), etc.

[0089] A first bus bar 120 and a second bus bar 125 extending in a first direction and spaced apart from each other in a second direction perpendicular to the first direction are formed on the substrate 100. The bus bars 120 and 125 may include a conductive substance.

[0090] A plurality of first IDT electrodes 130 and second IDT electrodes 135 are formed to alternately extend from the first bus bar 120 and the second bus bar 125 in the second direction and to be spaced apart in the first direction.

[0091] The first IDT electrode 130 may be formed in a form integral with the first bus bar 120 , and the second IDT electrode 135 may be formed in a form integral with the second bus bar 125 .

[0092] A region including the first and second bus bars 120 and 125 and the first and second IDT electrodes 130 and 135 is referred to as an IDT electrode portion 150 .

[0093] In addition, a pair of reflectors 180A and 180B may be formed on both sides of the IDT electrode portion 150 along the first direction on the substrate 100. In other words, the pair of reflectors 180A and 180B are configured to sandwich the IDT electrode portion 150. The reflector 180A on one side may be formed adjacent to the left side of the IDT electrode portion 150, and the reflector 180B on the other side may be formed adjacent to the right side of the IDT electrode portion 150.

[0094] The IDT electrodes 130 , 135 and the reflectors 180A, 180B may be formed of a single metal film or a stacked metal film. The IDT electrodes 130 , 135 and the reflectors 180A, 180B may be formed simultaneously with the bus bars 120 , 125 by the same process, for example, a deposition process.

[0095] In the region where the first IDT electrode 130 and the second IDT electrode 135 overlap, edge portions having a lower sound velocity than the center portion may be formed at both ends of the center portion.

[0096] Reference Figure 8 The area marking on the left side shows that the area corresponding to C2 or C3 represents the edge part, and the area corresponding to C1 represents the center part. The sound speed of the area corresponding to C2 or C3 can be formed to be lower than the sound speed of the area C1.

[0097] Reference Figure 8 In order to realize the area of ​​C2 or C3 as a low-velocity area, the plunger 162 can cross the multiple IDT electrodes 130 and 135 and be extended in an integral form. In other words, the plunger 162 can cross the multiple IDT electrodes 130 and 135 and fill the area between the multiple electrodes to form a strip. If the plunger 162 is added to the edge parts C2 and C3, the sound velocity of the edge parts C2 and C3 is lower than the sound velocity of the center part C1 of the IDT electrode.

[0098] As described above, the plug 162 covering the front end of the first IDT electrode 130 and the plug 162 covering the front end of the second IDT electrode 135 can be formed at two locations. In this case, the plug 162 covering the front end of the first IDT electrode 130 is called a lower plug 162, and the plug 162 covering the front end of the second IDT electrode 135 is called an upper plug 162.

[0099] Particularly in the surface acoustic wave resonator 110 according to one embodiment of the present invention, the upper and lower plugs 162 may be connected by the plug connection portion 163 in a region other than the IDT electrode portion 150 .

[0100] The plunger 162 and the plunger connection portion 163 may be formed at the same time and may include an insulator. At this time, the density of the plunger 162 and the plunger connection portion 163 is 5 g / cm 3 Below, the material may include at least one of SiO2, Ta2O5 and Al2O3.

[0101] On the other hand, Figure 8 , the plug connection portion 163 is shown to be located on the outer side of the reflectors 180A and 180B, but the plug connection portion 163 may be formed on the outer side of the IDT electrode portion 150. The plug connection portion 163 may also be formed between the reflectors 180A and 180B and the IDT electrode portion 150.

[0102] Fig. 9 As a plan view of a substrate of a surface acoustic wave filter according to an embodiment of the present invention, (a) shows a substrate formed by arranging a plurality of surface acoustic wave resonators, and (b) is a view of a photoresist mask for forming a plug and a plug connection portion on the substrate. The surface acoustic wave filter 10 can be formed with one or more surface acoustic wave resonators 110. It can be composed of one surface acoustic wave resonator 110 to form a single-band surface acoustic wave filter 10, or a plurality of surface acoustic wave resonators 110 can be connected in parallel to form a multi-band surface acoustic wave filter 10.

[0103] Reference Fig. 9 In (a), a plurality of surface acoustic wave resonators 110 are formed on a substrate 100 and connected in parallel, thereby completing a surface acoustic wave filter 10 .

[0104] Reference Figure 8 and Fig. 9 The upper and lower plungers 162 are connected by the plunger connecting portion 163 to form a closed graphic shape.

[0105] As described above, if the upper and lower plugs 162 and the plug connecting portion 163 are connected, during the stripping process, the resist stripping liquid 191 can penetrate more into the gap between the photoresist 190 and the dielectric 164, and since it is stripped in small blocks, the stripped blocks can be prevented from causing damage to the IDT electrode.

[0106] Fig.10 : are diagrams showing various connection examples of a plunger according to an embodiment of the present invention.

[0107] Reference Fig.10 In (a), the upper and lower plugs 162 can be connected in the regions of the reflectors 180A and 180B via a plug connecting portion 163 having the same thickness as the plug 162 of the IDT electrode portion 150 .

[0108] Reference Fig.10 In (b), the upper and lower plugs 162 are connected in the region of the reflectors 180A and 180B by a plug connection portion 163 having the same thickness as the plug 162 of the IDT electrode portion 150, but may include a disconnected section in between.

[0109] Reference Fig.10 (c), the upper and lower plungers 162 can be connected in the region of the reflectors 180A and 180B by a plunger connection portion 163 having a curved shape and the same thickness as the plunger 162 of the IDT electrode portion 150. In particular, in order to prevent the resist stripping liquid 191 from agglomerating but being evenly distributed, it is preferred that the shape of the connection portion avoids sharp angles and is processed with a curved shape.

[0110] Reference Fig.10 (d), the upper and lower plungers 162 can be connected in the regions of the reflectors 180A and 180B by a plunger connection portion 163 that is thicker than the plunger 162 of the IDT electrode portion 150. Forming the plunger connection portion 163 as thick as possible within the area that can be ensured in the surface acoustic wave resonator 110 is conducive to faster and deeper penetration of the resist stripping solution 191.

[0111] Reference Fig.10 (e), the upper and lower plungers 162 may be connected within the region of the reflectors 180A, 180B via a plunger connection portion 163 having a non-constant thickness.

[0112] Reference Fig.10 (f), the upper and lower plungers 162 may be connected via a plunger connection portion 163 that passes through all areas of the exterior and interior of the reflectors 180A, 180B.

[0113] exist Fig.10In all cases (a) to (f), the surface acoustic wave resonator 110 according to the present invention can confirm that the performance of suppressing stray components remains unchanged. Therefore, according to the design conditions of each surface acoustic wave resonator 110, the cases (a) to (f) can be combined to achieve design optimization.

[0114] Fig.11 As a plan view of a substrate including a plug connection within a surface acoustic wave filter according to an embodiment of the present invention, (a) shows a substrate formed by arranging a plurality of surface acoustic wave resonators, and (b) is a diagram of a photoresist mask for forming a plug and a plug connection on the substrate.

[0115] Reference Fig.11 , the surface acoustic wave resonator 110 may be connected to each other through other surface acoustic wave resonators 110 and the plug connection portion 163 arranged on the substrate 100. At this time, the plug connection portion 163 additionally formed for connection shall not infringe on the area of ​​the IDT electrode portion 150 of the surface acoustic wave resonator 110. In addition, the plug connection portion 163 formed outside the surface acoustic wave resonator 110 may be extended to the outer contour of the substrate 100. In addition, in order to connect the plug connection portion 163 and the surface acoustic wave resonator 110 to each other, the plug connection portion 163 may be extended from the inside of the surface acoustic wave resonator 110 to the outer contour.

[0116] Fig.12 FIG. 1 is a diagram showing an example of connection between plungers in adjacent surface acoustic wave filters according to an embodiment of the present invention.

[0117] Fig.12 (a) shows a case where two surface acoustic wave resonators are in contact and arranged one above the other. The surface acoustic wave resonators arranged at the upper and lower parts can be directly connected via a linear plug connection portion 163 .

[0118] Fig.12 (b) shows a case where two surface acoustic wave resonators are arranged in an up-and-down manner. The surface acoustic wave resonators arranged in the upper and lower parts can be connected via a plug connection part 163 that avoids the IDT electrode part 150 and has a straight line shape or a right angle shape.

[0119] As described above, when the plug connection portion 163 is formed by connecting other surface acoustic wave resonators 110 disposed on the same substrate 100 to each other or extending to the outer contour of the substrate 100, the area of ​​the plug connection portion 163 becomes wider, so the area that needs to be stripped in the stripping process is reduced, and the resist stripping liquid 191 may penetrate more during stripping, which is more conducive to preventing defects from occurring during stripping of the photoresist 190. Since the resist stripping agent 191 can quickly and fully penetrate into the gap between the photoresist 190 and the dielectric 164, and is stripped in a large number of small pieces during stripping, it is possible to further reduce the damage to the IDT electrodes 130 and 135 caused by the blocks stripped when stripping the photoresist 190.

[0120] The surface acoustic wave resonators 110 can also be connected in parallel to complete the surface acoustic wave filter 10 having multiple frequency bands.

[0121] In this way, even if adjacent surface acoustic wave resonators 110 are connected to each other by plug connection portions 163 of various shapes, the performance of suppressing stray components of the surface acoustic wave resonator 110 can be maintained. Even if the connection shape includes a disconnected section or is formed with an inconstant thickness, the performance does not deteriorate. Therefore, the plug 162 can be connected in various shapes according to the design conditions of each surface acoustic wave resonator 110, thereby achieving design optimization.

[0122] In order to prevent the resist stripping liquid 191 from agglomerating and to distribute it uniformly, it is preferable to make the shape of the connection portion into a curved line.

[0123] Although the present invention has been described above, a person having ordinary knowledge in the technical field to which the present invention pertains will recognize that the present invention can be implemented in other forms while maintaining the technical concept and essential features of the present invention.

[0124] Although the scope of rights of the present invention is basically determined by the patent claims, it should be interpreted that all changes or deformations derived from the structures directly derived from the matters recorded in the patent claims and the structures equivalent thereto are included in the scope of rights of the present invention.

Claims

1. A surface acoustic wave filter having a connected plunger, characterized in that The substrate on which a supporting substrate, an energy limiting layer and a piezoelectric layer are sequentially stacked comprises: An IDT electrode portion is formed with a first bus bar and a second bus bar and a plurality of first IDT electrodes and a second IDT electrode, wherein the first bus bar and the second bus bar are extended along a first direction and are spaced apart from each other along a second direction perpendicular to the first direction, and the plurality of first IDT electrodes and the second IDT electrodes are alternately extended from the first bus bar and the second bus bar along the second direction and are spaced apart from each other along the first direction; The lower plunger and the upper plunger are formed in a strip shape extending in a first direction so as to cover the front ends of the plurality of first IDT electrodes and the second IDT electrodes. The upper plug and the lower plug are connected by a plug connection portion in a region excluding the IDT electrode portion.

2. The surface acoustic wave filter with connected plungers according to claim 1, characterized in that Also included are reflectors formed on both sides of the IDT electrode portion along the first direction.

3. The surface acoustic wave filter with connected plungers according to claim 2, characterized in that The plunger connection is formed on the exterior of the reflector.

4. The surface acoustic wave filter with connected plungers according to claim 2, characterized in that The plunger connection is formed through the exterior and interior of the reflector.

5. The surface acoustic wave filter with connected plungers according to any one of claims 1 to 4, characterized in that The plunger connection portion includes a disconnection zone.

6. A surface acoustic wave filter with a connected plunger according to any one of claims 1 to 4, characterized in that The plunger connecting portion includes a curved section.

7. A surface acoustic wave filter with a connected plunger according to any one of claims 1 to 4, characterized in that The thickness of the plunger connection is not constant.

8. A method for manufacturing a surface acoustic wave filter, characterized in that: The steps include: An IDT electrode portion is formed on a substrate on which a support substrate, an energy limiting layer, and a piezoelectric layer are sequentially stacked, the IDT electrode portion comprising a first bus bar and a second bus bar and a plurality of first IDT electrodes and a second IDT electrode, wherein the first bus bar and the second bus bar extend along a first direction and are spaced apart from each other along a second direction perpendicular to the first direction, and the plurality of first IDT electrodes and second IDT electrodes extend alternately from the first bus bar and the second bus bar along the second direction and are spaced apart from each other along the first direction; and forming a lower plug and an upper plug in a strip shape extending in a first direction so as to cover the front ends of the plurality of first IDT electrodes and the second IDT electrodes, The upper plug and the lower plug are connected by a plug connection portion in a region excluding the IDT electrode portion.

9. A method for manufacturing a surface acoustic wave filter, characterized in that: The steps include: Simultaneously forming a plurality of surface acoustic wave resonators including an IDT electrode portion on a substrate on which a support substrate, an energy confinement layer, and a piezoelectric layer are sequentially stacked, wherein the IDT electrode portion includes a first bus bar and a second bus bar and a plurality of first IDT electrodes and a second IDT electrode, wherein the first bus bar and the second bus bar extend along a first direction and are spaced apart from each other along a second direction perpendicular to the first direction, and the plurality of first IDT electrodes and second IDT electrodes extend alternately from the first bus bar and the second bus bar along the second direction and are spaced apart from each other along the first direction; and forming a lower plug and an upper plug in a strip shape extending in a first direction so as to cover the front ends of the plurality of first IDT electrodes and the second IDT electrodes, A plurality of surface acoustic wave resonators are connected in parallel, and the plugs are connected by a plug connection portion in a region other than the IDT electrode portion.

10. The method for manufacturing a surface acoustic wave filter according to claim 8 or 9, characterized in that: The method further includes forming reflectors on both sides of the IDT electrode portion along the first direction.

11. The method for manufacturing a surface acoustic wave filter with a connected plunger according to claim 10, characterized in that: The plunger connection is formed on the exterior of the reflector.

12. The method for manufacturing a surface acoustic wave filter with a connected plunger according to claim 10, characterized in that: The plunger connection is formed through the exterior and interior of the reflector.

13. The method for manufacturing a surface acoustic wave filter according to claim 9, wherein: The plunger connection portion is formed to extend to the outer contour of the surface acoustic wave resonator.

14. The method for manufacturing a surface acoustic wave filter according to claim 9, wherein: The plunger connection portion is formed by connecting the surface acoustic wave resonator.

15. The method for manufacturing a surface acoustic wave filter according to claim 9, wherein: The plunger connection portion is formed to extend to the outer contour of the substrate.

16. The method for manufacturing a surface acoustic wave filter according to any one of claims 8 to 15, characterized in that: The plunger connection portion includes a disconnection zone.

17. The method for manufacturing a surface acoustic wave filter according to any one of claims 8 to 15, characterized in that: The plunger connecting portion includes a curved section.

18. The method for manufacturing a surface acoustic wave filter according to any one of claims 8 to 15, characterized in that: The thickness of the plunger connection is not constant.

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