An elastic wave device and an elastic wave apparatus using the same.

Abstract

This invention relates to the field of filter technology, and particularly to an elastic wave device and an elastic wave apparatus using the same. The device comprises: a piezoelectric substrate having opposing first and second surfaces; an elastic wave assembly disposed on the first surface of the piezoelectric substrate; a second wiring disposed on the first surface of the piezoelectric substrate, the second wiring including a bridging portion arranged along a first direction; a first insulator disposed on the upper surface of the bridging portion, the first insulator arranged along the first direction; and a first wiring disposed on the piezoelectric substrate and connected to the elastic wave assembly, the first wiring including a three-dimensional wiring portion that intersects the bridging portion of the second wiring across the first insulator, and a first connecting portion and a second connecting portion respectively connecting the two ends of the bridging portion along the first direction, the three-dimensional wiring portion being arranged along a second direction; the first and second directions are intersecting. Therefore, this invention provides a highly reliable elastic wave device.

Description

Technical Field

[0001] This invention relates to the field of filter technology, and in particular to an elastic wave device and an elastic wave apparatus using the same. Background Technology

[0002] Currently, filters using elastic waves (elastic wave devices) are widely used in the receiving circuits of mobile phones and other devices. As described in most manuals, their construction includes a resonator (elastic wave assembly) formed by placing comb-shaped electrodes on a piezoelectric substrate such as lithium tantalate or lithium niobate.

[0003] In this case, multiple wirings are sometimes made to intersect each other three-dimensionally in order to achieve miniaturization. For example, in a three-dimensional intersection, an upper layer wiring is formed on top of a lower layer wiring through an insulating layer.

[0004] Because the upper layer wiring spans the short sides of the two insulation layers, the insulation layers are prone to lifting and falling off due to the influence of external forces in subsequent manufacturing processes. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an elastic wave device and an elastic wave apparatus using the same.

[0006] To address the aforementioned technical problems, one of the technical solutions provided by this invention is as follows:

[0007] An elastic wave device, comprising:

[0008] A piezoelectric substrate having opposing first and second surfaces;

[0009] An elastic wave assembly is disposed on the first surface of the piezoelectric substrate;

[0010] A second wiring is disposed on the first surface of the piezoelectric substrate, and the second wiring includes a bridging portion arranged along a first direction;

[0011] A first insulator is disposed on the upper surface of the bridging portion, and the first insulator is arranged along a first direction;

[0012] The first wiring is disposed on the piezoelectric substrate and connected to the elastic wave component. The first wiring includes a three-dimensional wiring portion that intersects the second wiring portion through the first insulator, and a first connecting portion and a second connecting portion that respectively connect the two ends of the bridging portion along the first direction. The three-dimensional wiring portion is arranged along the second direction.

[0013] The first direction and the second direction are intersected; the dimension of the first insulator along the first direction is greater than the dimension along the second direction.

[0014] In a preferred embodiment, the first insulator has opposing first and second ends along a first direction;

[0015] The first connecting portion covers the first end and / or the second connecting portion covers the second end.

[0016] In a preferred embodiment, the second wiring includes an extension disposed on the lower surface of the first wiring, the projection of the extension on the piezoelectric substrate being within the range of the projection of the first wiring on the piezoelectric substrate, and the projection of the extension on the piezoelectric substrate being outside the range of the projection of the first insulator on the piezoelectric substrate.

[0017] In a preferred embodiment, the distance between the edge of the extension projected on the piezoelectric substrate and the edge of the first wiring projected on the piezoelectric substrate is greater than 2 μm.

[0018] In a preferred embodiment, the thickness of the first insulator is greater than 0.5 μm and less than 2.0 μm.

[0019] In a preferred embodiment, the thickness of the second wiring is greater than 1.2 μm and less than 6.0 μm.

[0020] In a preferred embodiment, the second wiring is made of materials with a resistivity of less than 2.5 × 10⁻⁶. -8 It is made of a conductive material with an Ω·m conductivity.

[0021] In a preferred embodiment, the thickness of the second wiring is greater than 0.5 μm and less than 3.0 μm.

[0022] In a preferred embodiment, the first insulator has a first side surface located on one side of the bridging portion and a second side surface located on the other side of the bridging portion, the first side surface and the second side surface being inclined; the inclination angle between the first side surface and the second side surface and the first surface of the piezoelectric substrate is less than 55°.

[0023] In a preferred embodiment, the first insulator has a first side surface located on one side of the bridging portion and a second side surface located on the other side of the bridging portion, the first side surface and the second side surface being curved surfaces; the inclination angle of the tangents at each point of the first side surface and the second side surface relative to the first surface of the piezoelectric substrate is less than 55°.

[0024] In a preferred embodiment, the angle of inclination of the tangents at each point on the first and second sides relative to the first surface of the substrate increases sequentially from top to bottom.

[0025] In a preferred embodiment, the elastic wave assembly includes forked electrodes and reflectors formed on the piezoelectric substrate. The forked electrodes include a pair of comb-shaped electrodes facing each other, each comb-shaped electrode having a plurality of electrode fingers and a busbar connected to the electrode fingers. The reflectors are disposed on both sides of the forked electrodes.

[0026] In a preferred embodiment, the elastic wave device further includes a second insulator covering the first wiring, the first insulator, and the second wiring.

[0027] The second technical solution provided by this invention is as follows:

[0028] An elastic wave device, comprising:

[0029] A piezoelectric substrate having opposing first and second surfaces;

[0030] An elastic wave assembly is disposed on the first surface of the piezoelectric substrate;

[0031] A second wiring is disposed on the first surface of the piezoelectric substrate, and the second wiring includes a bridging portion arranged along a first direction;

[0032] A first insulator is disposed on the bridging portion, and the first insulator is arranged along a first direction;

[0033] The first wiring is disposed on the piezoelectric substrate and connected to the elastic wave component. The first wiring includes a three-dimensional wiring portion that intersects the second wiring portion through the first insulator, and a first connecting portion and a second connecting portion that respectively connect the two ends of the bridging portion along the first direction. The three-dimensional wiring portion is arranged along the second direction.

[0034] The first direction and the second direction are intersected;

[0035] The first insulator has a first end and a second end opposite to each other along a first direction;

[0036] The first connecting portion covers the first end and / or the second connecting portion covers the second end.

[0037] In a preferred embodiment, the second wiring includes an extension disposed on the lower surface of the first wiring, the projection of the extension on the piezoelectric substrate being within the range of the projection of the first wiring on the piezoelectric substrate, and the projection of the extension on the piezoelectric substrate being outside the range of the projection of the first insulator on the piezoelectric substrate.

[0038] In a preferred embodiment, the distance between the edge of the extension projected on the piezoelectric substrate and the edge of the first wiring projected on the piezoelectric substrate is greater than 2 μm.

[0039] In a preferred embodiment, the first insulator has a first side surface located on one side of the bridging portion and a second side surface located on the other side of the bridging portion, the first side surface and the second side surface being inclined; the inclination angle between the first side surface and the second side surface and the first surface of the piezoelectric substrate is less than 55°.

[0040] In a preferred embodiment, the first insulator has a first side surface located on one side of the bridging portion and a second side surface located on the other side of the bridging portion, the first side surface and the second side surface being curved surfaces; the inclination angle of the tangents at each point of the first side surface and the second side surface relative to the first surface of the piezoelectric substrate is less than 55°.

[0041] In a preferred embodiment, the elastic wave device further includes a second insulator covering the first wiring, the first insulator, and the second wiring.

[0042] The third technical solution provided by this invention is as follows:

[0043] An elastic wave device includes: an elastic wave device as described above; and a circuit board on which the elastic wave device is mounted.

[0044] The present invention can avoid the stripping of the insulating material used to isolate intersecting wires in the three-dimensional wiring portion formed on the substrate.

[0045] Other features and beneficial effects of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other beneficial effects of the invention can be realized and obtained by means of the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Unless otherwise specified, the positional relationships shown in the drawings in the following description are based on the direction in which the components are drawn in the figure.

[0047] Figure 1 This is a cross-sectional view of the elastic wave device packaging structure according to the first embodiment of the present invention;

[0048] Figure 2 This is an example top view of the elastic wave component of the first embodiment being an elastic surface wave resonator;

[0049] Figure 3 This is a schematic top view of the electrode structure on a piezoelectric substrate;

[0050] Figure 4 yes Figure 2 An enlarged schematic diagram of the electrode structure on a portion of the piezoelectric substrate, shown by the dashed line;

[0051] Figure 4a It is along Figure 4 A sectional view of line A-A' in the diagram;

[0052] Figure 4b It is along Figure 4 A sectional view of line B-B' in the diagram;

[0053] Figure 5 This is a schematic top view of the three-dimensional intersection section in the prior art;

[0054] Figure 6 This is an enlarged schematic diagram of the electrode structure on a portion of the piezoelectric substrate according to the second embodiment of the present invention;

[0055] Figure 6a It is along Figure 6 A sectional view of line C-C' in the middle;

[0056] Figure 7 This is an enlarged schematic diagram of the electrode structure on a portion of the piezoelectric substrate according to the third embodiment of the present invention;

[0057] Figure 7a It is along Figure 7 A sectional view of the D-D' line in the diagram;

[0058] Figure 7b It is along Figure 7 A sectional view of the E-E' line in the middle;

[0059] Figure 8 This is the first embodiment of the present invention. Figure 4 The cross-sectional view along line A-A' in the figure is used to show the tilt angle of the first and second side surfaces;

[0060] Figure 9 This is the fourth embodiment of the present invention. Figure 4 A sectional view of line A-A' in the diagram;

[0061] Figure 10 This is the fifth embodiment of the present invention. Figure 4 A sectional view of line A-A' in the diagram;

[0062] Figure 11This is the sixth embodiment of the present invention. Figure 4 A sectional view of line A-A' in the diagram;

[0063] Figures 12-18 This is a schematic diagram of the manufacturing process of the elastic wave device according to the first embodiment of the present invention.

[0064] Figure label:

[0065] 1. Piezoelectric substrate; 2. Elastic wave assembly; 2a. Finger-shaped electrode; 2b. Reflector; 2c. Comb-shaped electrode; 2d. Electrode finger; 2e. Busbar; 3. First wiring; 31. Three-dimensional wiring section; 32. First connection section; 33. Second connection section; 4. Second wiring; 41. Bridging section; 42. Extension section; 5. First insulator; 5a. First side surface; 5b. Second side surface; 6. Second insulator; 7. Side wall section; 8. Cover; 9. External connection section; 10. Support substrate. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0067] In the description of this invention, it should be noted that all terms used in this invention (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains, and should not be construed as limiting the invention; it should be further understood that the terms used in this invention should be understood to have the same meaning as those in the context of this specification and in the relevant field, and should not be understood in an idealized or overly formal sense, except as expressly defined in this invention.

[0068] The different embodiments disclosed below may reuse the same reference numerals and / or designations. These repetitions are for the purpose of simplicity and clarity and are not intended to limit any specific relationship between the different embodiments and / or structures discussed.

[0069] Figure 1 and Figure 2 These are cross-sectional views of the elastic wave device packaging structure according to the first embodiment of the present invention and an example top view of the elastic wave component being an elastic surface wave resonator; in Figure 2 In the diagram, a top view is used to schematically remove [something]. Figure 1The structure of the side wall portion 7, the cover 8, and the external connecting portion 9 is shown, and the parts constituting the elastic wave assembly 2 are illustrated in a simplified diagram by using a symbol enclosed in a rectangular frame to represent the X; furthermore, Figure 1 Show along Figure 2 A cross-section of the elastic wave encapsulation structure of the I-I' line section.

[0070] like Figure 1 As shown, the elastic wave device packaging structure of the first embodiment includes a piezoelectric substrate 1, an elastic wave assembly 2, a sidewall portion 7, a cover 8, and an external connection portion 9.

[0071] In a first embodiment, the piezoelectric substrate 1 is made of a piezoelectric single crystal, such as lithium tantalate, lithium niobate, or quartz, or it may also be made of piezoelectric ceramic. In some embodiments, the piezoelectric substrate 1 may also be bonded to a support substrate 10, which is made of, for example, a sapphire substrate, an alumina substrate, a spinel substrate, or a silicon substrate. In a specific implementation, the piezoelectric substrate 1 includes a first surface 1a on which the elastic wave component 2 is disposed and a second surface 1b opposite to the first surface 1a, the second surface 1b being used to bond the support substrate 10.

[0072] The elastic wave component 2 is disposed on the first surface 1a of the piezoelectric substrate 1. In fact, the elastic wave component 2 has multiple resonators 2a, thereby constituting an elastic wave filter. More specifically, as... Figure 3 As shown, the resonator 2a includes a forked electrode (or interdigital transducer, or IDT) 2a for exciting elastic surface waves and a reflector 2b formed on the piezoelectric substrate 1. The forked electrode 2a includes a pair of opposing comb-shaped electrodes 2c. Each comb-shaped electrode 2c has multiple electrode fingers 2d and a busbar 2e connected to the electrode fingers 2d. The reflector 2b is disposed on both sides of the forked electrode 2a.

[0073] In the first embodiment, by providing a first wiring 3 and a second wiring 4 on the piezoelectric substrate 1 to connect the elastic wave component 2, the elastic wave component 2 is electrically connected to the wiring constituting the input terminal In, the output terminal Out, and the ground terminal GND. The first wiring 3 and the second wiring 4 can be made of suitable metals or alloys such as silver, aluminum, copper, titanium, and palladium.

[0074] The sidewall portion 7 surrounds the elastic wave assembly 2. The sidewall portion 7 is made of synthetic resin. Preferably, the sidewall portion 7 is made of photosensitive resin. Photosensitive resin is easily patterned using photolithography. This allows for the easy creation of openings that do not obstruct the vibration of the elastic wave assembly 2, or through-holes for wiring of the external connection portion 9. The photosensitive resin can be photosensitive polyimide, photosensitive epoxy resin, photosensitive silicone, etc. Preferably, photosensitive polyimide can be used to achieve precise patterning, but it is not limited to this.

[0075] The cover 8, in conjunction with the sidewall portion 7, forms and seals the elastic wave assembly 2 in a manner that does not impede its vibration, thereby creating a sealed cavity that allows the elastic wave assembly 2 to function normally. The cover 8 can be made of synthetic resin, such as epoxy resin or polyimide, but is not limited to these. Preferably, epoxy resin can be used, and the cover 8 is formed through a low-temperature curing process.

[0076] like Figure 2 As shown, the elastic wave component 2, along with the first wiring 3 and the second wiring 4, is formed on the piezoelectric substrate 1. To achieve the desired bandpass filter characteristics, the elastic wave component 2 can appropriately employ a DMS structure design and a ladder-shaped design. A portion of the first wiring 3 and a portion of the second wiring 4 constitute the wiring for the input terminal In, the output terminal Out, and the ground terminal GND, and the elastic wave component 2 is electrically connected to these input terminals In, the output terminal Out, and the ground terminal GND through the first wiring 3.

[0077] Figure 4 yes Figure 2 An enlarged schematic diagram of the electrode structure on a portion of the piezoelectric substrate, shown by the dashed line; Figure 4a and Figure 4b It is along Figure 4 A sectional view of lines A-A' and B-B' in the diagram.

[0078] In the first embodiment, as Figure 4As shown, a plurality of resonators are provided on the piezoelectric substrate 1 (this embodiment schematically shows 6 resonators, namely resonators 1, 2, 3, 4, 5, and 6). Resonators 1, 2, and 3 are electrically connected to resonators 4, 5, and 6 respectively through different lines of the first wiring 3. For example, resonator 1 is electrically connected to resonator 4 through the first connection part 32, resonator 3 is electrically connected to resonator 6 through the second connection part 33, and resonator 2 is electrically connected to resonator 5 through the three-dimensional wiring part 31. In order to connect resonators 1 and 4 with resonators 3 and 6, a bridging part 41 of the second wiring 4 is provided along the first direction, and a first insulator 5 is arranged along the same first direction and the first wiring 3 is arranged along a second direction that intersects with the first direction. The bridging part 41 of the second wiring 4 is isolated from the three-dimensional wiring part 31 of the first wiring 3 by the first insulator 5, so as to connect resonators 1 and 4 with resonators 3 and 6 that are at different potentials.

[0079] like Figure 4a , 4b As shown, the second wiring 4 is disposed on the first surface 1a of the piezoelectric substrate 1. The second wiring 4 includes a bridging portion 41 arranged along a first direction. In this embodiment, the first direction can be as follows: Figure 4 The x-axis direction is shown; in one or more preferred embodiments, the thickness of the second wiring 4 may be greater than 1.2 μm and less than 6.0 μm to improve the reliability of the first insulator 5 coverage; more preferably, the thickness of the second wiring 4 is greater than 1.8 μm and less than 4.0 μm. In one or more more preferred embodiments, the second wiring 4 may be made of materials with a resistivity of less than 2.5 × 10⁻⁶. -8 It is made of a conductive material with a conductivity of Ω·m, such as a metal material with high conductivity such as gold, silver or copper, or an alloy material with high conductivity, or a multilayer metal structure composed of multiple metal layers stacked together, thereby reducing its overall thickness. For example, the thickness of the second wiring 4 can be further reduced to 0.5μm to 3.0μm, further improving the reliability of the first insulator 5 coverage, thereby improving the overall reliability of the device.

[0080] A first insulator 5, made of insulating material and arranged along the first direction, is disposed on the bridging portion 41, covering the upper and side surfaces of the bridging portion 41. The insulating material may be, for example, polyimide (PI). To achieve device miniaturization while ensuring reliability, the film thickness of the first insulator 5 may be 0.5 μm or more and 2.0 μm or less, more preferably 0.8 μm or more and 1.2 μm or less. For example, the film thickness may be 0.8, 0.9, 1.0, 1.1, 1.2 μm, or any value between these two.

[0081] The first wiring 3 is disposed on the piezoelectric substrate 1 and electrically connected to the elastic wave assembly 2. The first wiring 3 includes a three-dimensional wiring portion 31 that intersects the bridging portion 41 of the second wiring 4 separated by the first insulator 5, and a first connecting portion 32 and a second connecting portion 33 that respectively connect the two ends of the bridging portion 41 along a first direction. The first connecting portion 32 and the second connecting portion 33 are used to connect different resonators respectively. The three-dimensional wiring portion 31 is arranged along a second direction, and the first direction and the second direction are intersected. Specifically, the second direction in this embodiment can be as follows: Figure 4 The y-axis direction is shown; in one or more preferred embodiments, the thickness of the first wiring 3 is subject to the frequency range applicable to the elastic wave device, for example, the thickness is about 400nm or 500nm or more at low frequencies (about 1.5KMHz) and about 100nm to 200nm at high frequencies (about 1.5KMHz); the material of the first wiring 3 may be, for example, made of suitable metals or alloys such as silver, aluminum, copper, titanium, palladium, etc., or may be made of the same material as the second wiring 4, or may be a multilayer metal structure composed of multiple metal layers stacked together.

[0082] However, it should be noted that in this three-dimensional intersection, although in the first embodiment the first direction is the x-axis direction and the second direction is the y-axis direction, that is, the second direction is orthogonal to the first direction, in fact, the second direction is only required to be a direction that intersects with the first direction, and is not limited to an orthogonal direction.

[0083] like Figure 4a and 4b As shown, in this three-dimensional intersection, along the perpendicular to Figure 2 In the planar direction, the piezoelectric substrate 1 is at the lowest position, and from bottom to top, the bridging part 41 of the second wiring 4, the first insulator 5, and the three-dimensional wiring part 31 of the first wiring 3 are arranged in sequence, thereby realizing the structure in which the first wiring 3 and the second wiring 4 form a three-dimensional intersection through the first insulator 5.

[0084] Currently, to achieve higher integration and miniaturization of devices, insulators are generally used to isolate the electrical connections between wiring layers. When this insulator is configured along a certain direction, its dimension along that direction is larger than its dimension perpendicular to that direction. Furthermore, as... Figure 5The elastic wave device shown generally includes a piezoelectric substrate 1, an elastic wave component (not shown), a first wiring 3, a second wiring 4, and a first insulator 5 in the prior art. In its three-dimensional intersection, the piezoelectric substrate 1 is at the lowest position. The first wiring 3, the first insulator 5, and the second wiring 4 are arranged sequentially from bottom to top along a plane perpendicular to the piezoelectric substrate 1. It can be seen that when the insulator is used to block electrical currents in different directions and the second wiring 4 is used to achieve a bridging effect, since the second wiring 4 and the first insulator 5 are arranged in the same direction, the second wiring 4 crosses the two short sides of the first insulator 5. This causes the edges of the first insulator 5 to easily lift and fall off due to the influence of external forces in subsequent processes.

[0085] In the first embodiment, a bridging portion 41 of the second wiring 4 arranged along a first direction is placed below the first insulator 5, and the first insulator 5 is then arranged on the bridging portion 41 along the same direction. Finally, a three-dimensional wiring portion 31 of the first wiring 3 is placed on the first insulator 5. The three-dimensional wiring portion 31 is arranged along a second direction that intersects with the first direction. Thus, unlike the prior art where the wiring layer (second wiring 4) covering the first insulator 5 is arranged in the same direction as the first insulator 5, this embodiment uses an intersecting arrangement of the insulator and the wiring layer covering it, so that the three-dimensional wiring portion 31 spans the two long sides of the first insulator 5. That is, in the first embodiment, as shown in the figure... Figure 4 As shown, the dimension (length) of the first insulator along the first direction is greater than the dimension (length) along the second direction. This structure effectively reduces the possibility of the first insulator 5 peeling off at the edges due to external forces during subsequent manufacturing, thereby improving the reliability of the elastic wave device.

[0086] Figure 6 This is an enlarged schematic diagram of the electrode structure on a portion of the piezoelectric substrate according to the second embodiment of the present invention; Figure 6a It is along Figure 6 A cross-sectional view of line C-C' in the diagram.

[0087] like Figure 6 As shown, a first wiring 3, a second wiring 4, and a first insulator 5 are formed on the piezoelectric substrate 1. The first insulator 5 has a first end and a second end opposite to each other along a first direction. In the second embodiment, the first connecting portion 32 of the first wiring 3 covers the first end, and the second connecting portion 33 covers the second end. By adopting the above structure, the connecting portion of the first wiring 3 can cover both ends of the first insulator 5 along the first direction, which can more effectively prevent the first insulator 5 from being affected by external forces during subsequent manufacturing and thus affecting the performance of the product, thereby further improving the reliability of the elastic wave device.

[0088] It should be noted that, preferably, in the second embodiment, the first connecting portion 32 and the second connecting portion 33 respectively cover both ends of the first insulator 5 along the first direction. It is foreseeable that when only one of the first connecting portion 32 and the second connecting portion 33 is implemented to cover one end of the opposite side of the first insulator 5 along the first direction, it can also solve the problem of the first insulator 5 peeling off at the edge due to external force in subsequent processes and play a positive role.

[0089] Other configurations of the second embodiment may be the same as those of the first embodiment, and therefore will not be described in detail here.

[0090] Figure 7 This is an enlarged schematic diagram of the electrode structure on a portion of the piezoelectric substrate according to the third embodiment of the present invention; Figure 7a and Figure 7b They are along Figure 7 A sectional view of lines D-D' and E-E' in the diagram.

[0091] like Figure 7 As shown, a first wiring 3, a second wiring 4, and a first insulator 5 are formed on a piezoelectric substrate 1. The second wiring 4 includes an extension portion 42 disposed on the lower surface of the first wiring 3. The projection of the extension portion 42 on the piezoelectric substrate 1 is within the range of the projection of the first wiring 3 on the piezoelectric substrate 1, and the projection of the extension portion 42 on the piezoelectric substrate 1 is outside the range of the projection of the first insulator 5 on the piezoelectric substrate 1. The thickness of the first wiring 3 is relatively thin, generally at the nanometer level. The materials used for the first wiring 3 and the second wiring 4 are both conductive materials. In particular, they can also use the same material. Therefore, by forming the extension portion 42 of the second wiring 4 below the first wiring 3, the thickness of the wiring, especially the thickness of the first wiring 3, is increased, which can reduce the insertion loss.

[0092] Other configurations of the third embodiment may be the same as those of the first embodiment, and therefore will not be described in detail here.

[0093] In one or more preferred embodiments, such as Figure 7 As shown, the extension portion 42 may be arranged on the lower surface of the three-dimensional wiring portion 31, and the projection of the extension portion 42 on the piezoelectric substrate 1 is outside the range of the projection of the first insulator 5 on the piezoelectric substrate 1.

[0094] In one or more preferred embodiments, such as Figure 7 As shown, the extension portion 42 may be arranged on the lower surface of the first connecting portion 32, and the projection of the extension portion 42 on the piezoelectric substrate 1 is located outside the range of the projection of the first connecting portion 32 on the piezoelectric substrate 1.

[0095] In one or more preferred embodiments, such as Figure 7 As shown, the extension portion 42 may be arranged on the lower surface of the second connecting portion 33, and the projection of the extension portion 42 on the piezoelectric substrate 1 is located outside the range of the projection of the second connecting portion 33 on the piezoelectric substrate 1.

[0096] It is worth noting that, as can be seen from the above embodiments, as... Figure 2 As shown, the extension portion 42 of the second wiring 4 can also be disposed below other first wirings 3 to increase the thickness of the first wirings 3 and reduce insertion loss.

[0097] In one or more preferred embodiments, the distance between the edge of the extension portion 42 projected on the piezoelectric substrate 1 and the edge of the first wiring 3 projected on the piezoelectric substrate 1 is greater than 2 μm, preferably greater than 3 μm, thereby preventing pattern offset from affecting the IDT while reducing device insertion loss.

[0098] Figure 8 This is the first embodiment of the present invention. Figure 4 A sectional view of line A-A' in the diagram;

[0099] like Figure 8 As shown, in the first embodiment, the first insulator 5 has a first side surface 5a located on one side of the bridging portion 41 and a second side surface 5b located on the other side of the bridging portion 41. The first side surface 5a and the second side surface 5b are inclined surfaces. The inclination angle between the first side surface and the second side surface and the first surface 1a of the piezoelectric substrate 1 is less than 55°. Preferably, the inclination angle between the first side surface 5a and the second side surface 5b and the first surface 1a of the piezoelectric substrate 1 is less than 50°. Thus, by making the inclination angle of the first side surface 5a and the second side surface 5b of the first insulator 5 gentler, the inclination angle of the first wiring 3 formed on the first insulator 5 is also made gentler. Thus, cracks and breaks in the first wiring 3 can be effectively suppressed.

[0100] Figure 9 This is the fourth embodiment of the present invention. Figure 4 A sectional view of line A-A' in the diagram;

[0101] like Figure 9As shown, in the fourth embodiment, the first insulator 5 has a first side surface 5a located on one side of the bridging portion 41 and a second side surface 5b located on the other side of the bridging portion 41. The first side surface 5a and the second side surface 5b have lower side surface portions 5a1 and 5b1 with relatively large inclination angles and upper side surface portions 5a2 and 5b2 with relatively small inclination angles. The inclination angles of the first side surface 5a and the second side surface 5b with the first surface 1a of the piezoelectric substrate 1 are less than 55°. As a result, the change of the first wiring 3 from the aforementioned side surfaces 5c1 and 5c2 to the side surfaces 5d1 and 5d2 is made gentle. Therefore, cracks and breaks in the first wiring 3 can be suppressed more effectively.

[0102] Figure 10 This is the fifth embodiment of the present invention. Figure 4 A sectional view of line A-A' in the diagram;

[0103] like Figure 10 As shown, in the fifth embodiment, in the third embodiment, the first insulator 5 has a first side surface 5a located on one side of the bridging portion 41 and a second side surface 5b located on the other side of the bridging portion 41. The first side surface 5a and the second side surface 5b are curved surfaces. The inclination angle between the first side surface 5a and the second side surface 5b and the first surface 1a of the piezoelectric substrate 1 is less than 55°. By making the first side surface 5a and the second side surface 5b curved surfaces, the contact point between the first wiring 3 and the first insulator 5 is a smooth arc, rather than a protrusion with a certain angle, making the changes in the first wiring 3 smoother. Therefore, cracks and breaks in the first wiring 3 can be suppressed more effectively. More preferably, in the fourth embodiment, the inclination angle of the tangents at each point of the first side surface 5a and the second side surface 5b relative to the first surface 1a of the piezoelectric substrate 1 increases sequentially from top to bottom.

[0104] Figure 11 This is the sixth embodiment of the present invention. Figure 4 A sectional view of line A-A' in the diagram;

[0105] like Figure 11As shown, in the sixth embodiment, the elastic wave device further includes a second insulator 6, covering the first wiring 3, the first insulator 5, and the second wiring 4; the second insulator 6 can be made of materials such as silicon dioxide or silicon nitride; the thickness of the second insulator 6 is above 20 nm and below 40 nm. It is worth noting that in the prior art, to achieve frequency adjustment of the elastic wave component 2, after completing the fabrication process of the first wiring 3 and the elastic wave component 2, a layer of Si compound, such as silicon dioxide or silicon nitride, needs to be deposited to achieve frequency adjustment of the elastic wave component 2. After completing the fabrication process of the second wiring 4, to achieve moisture isolation and protection of the second wiring 4, another layer of Si compound needs to be deposited. However, in the elastic wave device provided by this invention, since the second wiring 4 layer is placed below the first wiring 3, in this device structure, only a layer of Si compound forming the second insulator 6 needs to be deposited after the first wiring 3 and the elastic wave component 2 are formed. This second insulator 6 can simultaneously achieve frequency adjustment of the elastic wave component 2 and overall moisture isolation.

[0106] A method for fabricating an elastic wave device according to the first embodiment of the present invention is provided, comprising the following steps:

[0107] Step 1, Combining Figure 4 and Figure 12 As shown, a piezoelectric substrate 1 is provided, having a first surface 1a and a second surface 1b opposite to each other. Optionally, the piezoelectric substrate 1 is subjected to a cleaning operation to remove dirt from the surface of the piezoelectric substrate 1.

[0108] Step 2, Combining Figure 4 and Figures 13 to 15 As shown, a second wiring 4 is formed on the piezoelectric substrate 1. The second wiring 4 includes a bridging portion 41 arranged along the first direction. Specifically, the second wiring 4 can be completed by using a method of positive adhesive to negative adhesive combined with ammonia baking machine full exposure, followed by metal evaporation of the second wiring 4, and then using a conventional lift-off process to peel the metal from the adhesive.

[0109] Step 3, Combining Figure 4 and Figure 16 As shown, a first insulator 5 is formed on the bridging portion 41 and the first insulator is arranged along a first direction. Specifically, the first insulator 5 can be formed by a conventional coating and exposure process.

[0110] Step 4, Combining Figure 4 He Ru Figure 17As shown, a first wiring 3 and an elastic wave component 5 are formed on the first insulator 5 and the piezoelectric substrate 1, respectively. Specifically, the first wiring 3 and the elastic wave component 2 can be generated using a conventional bi-layer process. The first wiring 3 connects to the elastic wave component 2. The first wiring 3 includes a three-dimensional wiring portion 31 that intersects the first insulator 5 and the second wiring 4 through a bridging portion 41, and a first connecting portion 32 and a second connecting portion 33 that connect the two ends of the bridging portion along a first direction. The first direction and the second direction are intersected.

[0111] Step 5, Combining Figure 4 He Ru Figure 18 As shown, a second insulator 6 is formed, covering the elastic wave component 2, the first wiring 3, the first insulator 5, and the second wiring 4, for frequency adjustment of the elastic wave component 2. Specifically, the second insulator can be formed by film deposition methods such as sputtering or evaporation, followed by patterning using photolithography etching. The etching method is not particularly limited; dry etching or wet etching can be selected based on the type of material. The second insulator 6 can be made of Si compound materials, such as silicon dioxide or silicon nitride.

[0112] Furthermore, those skilled in the art should understand that although many problems exist in the prior art, each embodiment or technical solution of the present invention can be improved in only one or a few aspects, without necessarily solving all the technical problems listed in the prior art or the background art simultaneously. Those skilled in the art should understand that any content not mentioned in a claim should not be construed as a limitation on that claim.

[0113] Although this document frequently uses terms such as piezoelectric substrate, elastic wave assembly, forked electrode, reflector, comb electrode, electrode finger, busbar, first wiring, three-dimensional wiring portion, first connection portion, second connection portion, second wiring, bridging portion, extension portion, first insulator, first side surface, second side surface, second insulator, sidewall portion, cover, and external connection portion, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of the invention; interpreting them as any additional limitation would contradict the spirit of the invention. The terms "first," "second," etc. (if present) in the specification, claims, and accompanying drawings of the embodiments of the invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An elastic wave device, comprising: A piezoelectric substrate having opposing first and second surfaces; An elastic wave assembly is disposed on the first surface of the piezoelectric substrate; A second wiring is disposed on the first surface of the piezoelectric substrate, and the second wiring includes a bridging portion arranged along a first direction; A first insulator is disposed on the bridging portion, and the first insulator is arranged along a first direction; The first wiring is disposed on the piezoelectric substrate and connected to the elastic wave component. The first wiring includes a three-dimensional wiring portion that intersects the second wiring portion through the first insulator, and a first connecting portion and a second connecting portion that respectively connect the two ends of the bridging portion along the first direction. The three-dimensional wiring portion is arranged along the second direction. The first direction and the second direction are intersecting; the dimension of the first insulator along the first direction is larger than its dimension along the second direction; The second wiring includes an extension portion disposed on the lower surface of the first wiring, the projection of the extension portion on the piezoelectric substrate being within the range of the projection of the first wiring on the piezoelectric substrate, and the projection of the extension portion on the piezoelectric substrate being outside the range of the projection of the first insulator on the piezoelectric substrate.

2. The elastic wave device according to claim 1, characterized in that: The first insulator has a first end and a second end opposite to each other along a first direction; The first connecting portion covers the first end and / or the second connecting portion covers the second end.

3. The elastic wave device according to claim 1, characterized in that: The distance between the edge of the extension portion projected onto the piezoelectric substrate and the edge of the first wiring projected onto the piezoelectric substrate is greater than 2 μm.

4. The elastic wave device according to claim 1, characterized in that: The thickness of the first insulator is greater than 0.5 μm and less than 2.0 μm.

5. The elastic wave device according to claim 1, characterized in that: The thickness of the second wiring is above 1.2 μm and below 6.0 μm.

6. The elastic wave device according to claim 1, characterized in that: The second wiring is made of materials with a resistivity of less than 2.5 × 10⁻⁶. -8 It is made of a conductive material with an Ω·m conductivity.

7. The elastic wave device according to claim 6, characterized in that: The thickness of the second wiring is greater than 0.5 μm and less than 3.0 μm.

8. The elastic wave device according to claim 1, characterized in that: The first insulator has a first side surface located on one side of the bridging portion and a second side surface located on the other side of the bridging portion, the first side surface and the second side surface being inclined surfaces; the inclination angle between the first side surface and the second side surface and the first surface of the piezoelectric substrate is less than 55°.

9. The elastic wave device according to claim 1, characterized in that: The first insulator has a first side surface located on one side of the bridging portion and a second side surface located on the other side of the bridging portion, and the first side surface and the second side surface are curved surfaces; the inclination angle of the tangents at each point of the first side surface and the second side surface relative to the first surface of the piezoelectric substrate is less than 55°.

10. The elastic wave device according to claim 9, characterized in that: The inclination angles of the tangents at each point on the first and second sides relative to the first surface of the substrate increase sequentially from top to bottom.

11. The elastic wave device according to claim 1, characterized in that: The elastic wave assembly includes finger-shaped electrodes and reflectors formed on the piezoelectric substrate. The finger-shaped electrodes include a pair of comb-shaped electrodes arranged opposite each other. Each comb-shaped electrode has multiple electrode fingers and a busbar connected to the electrode fingers. The reflectors are disposed on both sides of the finger-shaped electrodes.

12. The elastic wave device according to claim 1, characterized in that, The elastic wave device further includes a second insulator covering the first wiring, the first insulator, and the second wiring.

13. An elastic wave device, comprising: A piezoelectric substrate having opposing first and second surfaces; An elastic wave assembly is disposed on the first surface of the piezoelectric substrate; A second wiring is disposed on the first surface of the piezoelectric substrate, and the second wiring includes a bridging portion arranged along a first direction; A first insulator is disposed on the bridging portion, and the first insulator is arranged along a first direction; The first wiring is disposed on the piezoelectric substrate and connected to the elastic wave component. The first wiring includes a three-dimensional wiring portion that intersects the second wiring portion through the first insulator, and a first connecting portion and a second connecting portion that respectively connect the two ends of the bridging portion along the first direction. The three-dimensional wiring portion is arranged along the second direction. The first direction and the second direction are intersected; The first insulator has a first end and a second end opposite to each other along a first direction; The first connecting portion covers the first end and / or the second connecting portion covers the second end.

14. The elastic wave device according to claim 13, characterized in that: The second wiring includes an extension portion disposed on the lower surface of the first wiring, the projection of the extension portion on the piezoelectric substrate being within the range of the projection of the first wiring on the piezoelectric substrate, and the projection of the extension portion on the piezoelectric substrate being outside the range of the projection of the first insulator on the piezoelectric substrate.

15. The elastic wave device according to claim 14, characterized in that: The distance between the edge of the extension portion projected onto the piezoelectric substrate and the edge of the first wiring projected onto the piezoelectric substrate is greater than 2 μm.

16. The elastic wave device according to claim 13, characterized in that: The first insulator has a first side surface located on one side of the bridging portion and a second side surface located on the other side of the bridging portion, the first side surface and the second side surface being inclined surfaces; the inclination angle between the first side surface and the second side surface and the first surface of the piezoelectric substrate is less than 55°.

17. The elastic wave device according to claim 13, characterized in that: The first insulator has a first side surface located on one side of the bridging portion and a second side surface located on the other side of the bridging portion, and the first side surface and the second side surface are curved surfaces; the inclination angle of the tangents at each point of the first side surface and the second side surface relative to the first surface of the piezoelectric substrate is less than 55°.

18. The elastic wave device according to claim 13, characterized in that, The elastic wave device further includes a second insulator covering the first wiring, the first insulator, and the second wiring.

19. An elastic wave device, characterized in that, The elastic wave device comprises: an elastic wave device according to any one of claims 1 to 18; and a circuit board on which the elastic wave device is mounted.

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