Elastic wave device

Abstract

The present invention relates to a novel structure of an elastic wave device, and provides a novel structure of an elastic wave device, which realizes an increase in Q value without impairing the freedom of layout of a circuit pattern. At least one resonator in the circuit pattern is configured as a split resonator, which is formed by connecting three or more unit resonators in parallel through a parallel connection wiring. The unit resonators are arranged in parallel along a direction y orthogonal to a propagation direction x of an elastic surface wave. The parallel connection wiring has a first portion extending along the propagation direction x, and a second portion extending along the orthogonal direction y. The number of electrode fingers configuring the unit resonators differs from one another among all the unit resonators, or is not equal to one another between at least one unit resonator and another at least one unit resonator.

Description

Technical Field

[0001] This invention relates to improvements in elastic wave devices. Background Technology

[0002] Elastic wave devices, as frequency filters, are used in mobile communication equipment and other applications.

[0003] The elastic wave device has the following structure: on the functional surface of a device chip, which has at least one side being a functional surface made of piezoelectric material, a circuit pattern containing a resonator with IDT electrodes is formed.

[0004] Figure 10 A typical example of the circuit pattern is shown.

[0005] exist Figure 10 In the diagram, symbol 100 represents a port used for input / output, symbol 101 represents grounding, symbol 102a represents a resonator 102 connected in series, and symbol 102b represents a resonator 102 connected in parallel.

[0006] Figure 11 and Figure 12 A typical example of the resonator 102 is shown. For example... Figure 11 As shown, the resonator 102 is constructed by arranging IDT electrodes 104 between the reflectors 103.

[0007] The IDT electrode 104 has the following structure: two busbars 105 extending along the propagation direction x of the elastic surface wave, which is the main mode, are arranged opposite each other at a predetermined interval in a perpendicular direction y that is perpendicular to the propagation direction x. Meanwhile, between the two busbars 105, electrode fingers 106 extending along the perpendicular direction y are arranged at predetermined intervals between adjacent electrode fingers 106 in the propagation direction x, thereby arranging a plurality of electrode fingers 106 side by side.

[0008] One comb electrode 107 is formed by one of the two busbars 105 and the electrode finger 106 connected thereto, and the other comb electrode 107 is formed by the other of the two busbars 105 and the electrode finger 106 connected thereto.

[0009] The two comb electrodes 107 are configured at any position in the propagation direction x such that an electrode finger 106 of the other comb electrode 107 is disposed between adjacent electrode fingers 106 of one comb electrode 107, that is, they are configured to mesh with each other.

[0010] Furthermore, the reflector 103 has the following structure: two busbars 108 extending along the propagation direction x are arranged opposite each other at a predetermined interval in a perpendicular direction y, which is perpendicular to the propagation direction x. Meanwhile, between the two busbars 108, electrode fingers 109 extending along the perpendicular direction y are arranged at predetermined intervals between adjacent electrode fingers 109 in the propagation direction x, thereby arranging a plurality of electrode fingers 109 side-by-side. Each electrode finger 109 is connected to one of the two busbars 108.

[0011] The resonator 102 constructed as described above has a rectangular forming region, and, as... Figure 12 As shown, the width W along the propagation direction x and the length L along the orthogonal direction y can be identified.

[0012] Here, the higher the series resistance of the IDT electrode, the lower the Q value of the resonator 102. This series resistance increases with the length of the electrode finger 106, that is, it increases with the length L of the region forming the resonator 102.

[0013] like Figure 13 As shown, if the length L of the forming region of the resonator 102 is set as... Figure 12 The length L of the forming region of the resonator 102 shown is approximately half of the length of the region, and the width W of the forming region of the resonator 102 is set as... Figure 12 If the width W of the forming region of the resonator 102 shown is approximately twice that of the resonator, it is possible to reduce the series resistance while forming a structure with the same characteristics as the resonator 102 shown. Figure 12 The resonator 102 shown is a resonator 102 with the same performance.

[0014] However, the resonator 102, which has a significantly increased width W relative to the length L of the forming region, reduces the degree of layout freedom when the circuit pattern is laid out on the functional surface. Summary of the Invention

[0015] The main problem to be solved by the present invention is to improve the Q value by reducing the series resistance in this type of elastic wave device without compromising the above-mentioned layout freedom, and to provide a new structure.

[0016] To achieve the above-mentioned problems, the present invention, starting from a first point of view, proposes an elastic wave device, which is as follows: An elastic wave device is formed on the functional surface of a device chip, where at least one side is a functional surface made of piezoelectric material, by forming a circuit pattern including a resonator with IDT electrodes. In this circuit pattern, at least one of the resonators is a segmented resonator, which is formed by connecting at least three unit resonators, each functioning as a resonator, in parallel using wiring. The unit resonators are arranged in parallel along a direction perpendicular to the propagation direction of the elastic surface wave excited by the IDT electrodes. The parallel connection wiring has a first portion extending along the propagation direction and a second portion extending along the orthogonal direction. Furthermore, the number of electrode fingers constituting the unit resonator is not equal between at least one unit resonator and at least another unit resonator.

[0017] Furthermore, to achieve the above-mentioned problem, this invention proposes an elastic wave device from a second perspective, wherein the elastic wave device is: An elastic wave device is formed on the functional surface of a device chip, where at least one side is a functional surface made of piezoelectric material, by forming a circuit pattern including a resonator with IDT electrodes. In this circuit pattern, at least one of the resonators is a segmented resonator, which is formed by connecting at least three unit resonators, each functioning as a resonator, in parallel using wiring. The unit resonators are arranged in parallel along a direction perpendicular to the propagation direction of the elastic surface wave excited by the IDT electrodes. The parallel connection wiring has a first portion extending along the propagation direction and a second portion extending along the orthogonal direction. Furthermore, the number of electrode fingers constituting the unit resonator differs from one another in all the unit resonators. Alternatively, the number of electrode fingers constituting the unit resonator is not equal between at least one unit resonator and at least another unit resonator, while the split resonator includes at least two unit resonators with an equal number of electrode fingers.

[0018] In one embodiment of the present invention, the three or more unit resonators in the propagation direction include: at least one inner resonator adjacent to each of the unit resonators on both sides, and two outer resonators adjacent to the unit resonators as inner resonators on only one side; and the number of electrode fingers constituting at least one of the two outer resonators is greater than the number of electrode fingers of the inner resonator adjacent to it.

[0019] As one embodiment of the present invention, the three or more unit resonators further include, in the propagation direction, at least one inner resonator adjacent to the unit resonator on both sides, and two outer resonators adjacent only on one side to the unit resonator as the inner resonator. Furthermore, the number of electrode fingers of the outer resonator of one side is greater than the number of electrode fingers constituting the inner resonator, while the number of electrode fingers of the outer resonator of the other side is less than the number of electrode fingers of the adjacent inner resonator.

[0020] As one embodiment of the present invention, the width of the first portion of the parallel connection wiring is made larger on the base side integrated with the second portion and smaller on the opposite end side.

[0021] As an embodiment of the present invention, the parallel connection wiring further includes: a wiring element on one side having the first portion and the second portion, and a wiring element on the other side having the first portion and the second portion; In the propagation direction, the second portions of the two wiring elements are spaced apart from each other and arranged relative to each other; Furthermore, in the orthogonal direction, the first portion of the wiring element on one side is adjacent to the first portion of the wiring element on the other side, separated from the unit resonator by the unit resonator; simultaneously, the first portion of the wiring element on the other side is adjacent to the first portion of the wiring element on one side, separated from the unit resonator by the unit resonator. This allows the wiring elements on one side to be configured in an interlocking manner with the wiring elements on the other side.

[0022] In one embodiment of the present invention, at least one side of the outer contour line along the orthogonal direction in the forming region of the segmented resonator is formed into a straight line by the outer edge of the second part of either the wiring element on one side or the wiring element on the other side, together with the end edge of the unit resonator along the orthogonal direction.

[0023] In one embodiment of the present invention, the width of the unit resonator is 200 to 400 μm and its length is 50 to 100 μm.

[0024] In one embodiment of the present invention, the width of the wiring for the parallel connection is 10 to 30 μm.

[0025] In one embodiment of the present invention, the conductive metal layer of the unit resonator and the parallel connection wiring is made of aluminum or an alloy mainly composed of aluminum.

[0026] According to the present invention, by means of the segmented resonator, in this type of elastic wave device, the Q value can be appropriately and effectively improved by reducing the series resistance without compromising the aforementioned layout freedom. Attached Figure Description

[0027] Figure 1 This is a three-dimensional structural schematic diagram of an elastic wave device (first example) related to an embodiment of the present invention, wherein the resonator formed on the functional surface is represented by solid lines and dashed lines, and the rest of the structure is omitted.

[0028] Figure 2 This is a schematic diagram of the planar structure of the split resonator constituting the first example, showing the state of the split resonator as viewed from a direction perpendicular to the functional plane.

[0029] Figure 3 This is an example circuit diagram showing a circuit formed on the functional surface of the device chip.

[0030] Figure 4 This is a schematic diagram of the planar structure of the unit resonator that constitutes the segmented resonator in the first example.

[0031] Figure 5 This is a schematic diagram of another structural example (the second example) of the segmented resonator.

[0032] Figure 6 This is a schematic diagram of another structural example (the third example) of the segmented resonator.

[0033] Figure 7 This is a schematic diagram of another structural example (the 4th example) of the segmented resonator.

[0034] Figure 8 This is a schematic diagram of another structural example (the 5th example) of the segmented resonator.

[0035] Figure 9 This is a schematic diagram of the planar structure of a segmented resonator related to the comparative scale.

[0036] Figure 10 This is a circuit diagram illustrating an example of a circuit formed on the functional surface of an elastic wave device.

[0037] Figure 11 This is a schematic diagram of the planar structure of a resonator.

[0038] Figure 12 This is a schematic diagram of the conceptual structure of a resonator.

[0039] Figure 13 This is a schematic diagram of the conceptual structure of a resonator.

[0040] Figure label: x direction of propagation y orthogonal direction W width L length D Dead Zone 1. Elastic wave device 2. Device Chips 2a Functional surface 2b Back 2c Side View 3 Resonators 4. Segmented resonator 4a, 4b Outer contour lines 5-unit resonator 5a inner resonator 5b External resonator configuration 5c, 5d edge 6. Wiring for parallel connection 6a Part 1 6b Part Two 6c One-sided wiring elements 6d Wiring elements on the other side 6e base 6f end 6g outer edge 7. Wiring between resonators 8. External connection cabling 9 Input / Output Ports 10 Grounding 11 Reflectors 11a Busbar 11b electrode finger 12IDT electrode 12a Busbar 12b electrode finger 12c comb electrode 13. Gap. Detailed Implementation

[0041] The following will refer to Figures 1 to 9 Typical embodiments of the present invention will be described below. The elastic wave device 1 involved in this embodiment is suitable for use as a frequency filter, etc., and is suitable for mobile communication devices, etc.

[0042] The elastic wave device 1 according to this embodiment is constructed by forming a circuit pattern made of a conductive metal layer on the functional surface 2a of a single device chip 2, which has at least one functional surface 2a made of a piezoelectric material.

[0043] like Figure 1 As shown, the device chip 2 typically has the functional surface 2a and a back surface 2b opposite to the functional surface 2a. Figure 1 As shown, the device chip 2 also has four sides 2c, and the whole is in the shape of a flat hexahedron.

[0044] Lithium tantalate or lithium niobate are typically used as the piezoelectric element.

[0045] The device chip 2 can also be formed by stacking sapphire, silicon, alumina, spinel, quartz or glass on the piezoelectric body.

[0046] On the other hand, the circuit pattern includes multiple resonators 3 and inter-resonator wiring 7 for connecting the resonators 3 to each other (see Figure 3 ), and external connection wiring 8 for connecting the resonator 3 to the outside (see Figure 3 ).

[0047] In the example diagram, the circuit pattern includes five resonators 3. Figure 1 In the middle, among the five resonators 3, Figure 3 In the circuit, the resonator 3, which serves as the segmented resonator 4, is represented by a solid line, while the formation regions of the other four resonators 3 are represented by dashed lines.

[0048] By using bumps (not shown) or the like, the device chip 2 is mounted on a packaging substrate (not shown), thereby creating a space above the resonator 3, thus forming an elastic wave device with a CSP (Chip Size Package) structure.

[0049] Furthermore, by forming a wall layer (not shown) around the resonator 3 on the functional surface 2a of the device chip 2, and forming a capping layer (not shown) on the wall layer, the capping layer, together with the wall layer and the functional surface 2a, forms an internal space for accommodating the resonator 3, thereby constituting an elastic wave device with a WLP (Wafer Level Package) structure.

[0050] The circuit pattern is typically formed on the functional surface 2a by a conductive metal layer formed by photolithography.

[0051] Figure 3 A circuit diagram illustrating one configuration example of the circuit pattern.

[0052] exist Figure 3 In the diagram, symbol 9 represents an input / output port, and symbol 10 represents grounding.

[0053] exist Figure 3 In the diagram, symbol 3a represents a resonator 3 connected in series, and symbol 3b represents a resonator 3 connected in parallel.

[0054] In this embodiment, at least one resonator 3 in the circuit pattern is configured as a segmented resonator 4, which is formed by connecting at least three or more unit resonators 5, each functioning as a resonator, in parallel via wiring 6.

[0055] In the example diagram, such as Figure 1 and Figure 3 As shown, among the five resonators 3 constituting the circuit pattern, one of them is configured as a split resonator 4.

[0056] The unit resonators 5 are arranged in parallel along the orthogonal direction y of the propagation direction x of the elastic surface wave excited by the IDT electrode.

[0057] exist Figures 1 to 4 The first example shown and Figure 5 In the second example shown, the segmented resonator 4 is composed of four unit resonators 5 and wiring 6 connected in parallel.

[0058] exist Figure 6 The third example shown, Figure 7 The fourth case shown and Figure 8 In the fifth example shown, the segmented resonator 4 is composed of three unit resonators 5 and parallel connecting wiring 6.

[0059] Each unit resonator 5 as shown Figure 4 As shown, they are all constructed by arranging IDT electrodes 12 between a pair of reflectors 11.

[0060] The IDT electrode 12 has the following structure: two busbars 12a extending along the propagation direction x of the elastic surface wave, which is the main mode, are arranged opposite each other at a predetermined interval in a perpendicular direction y that is perpendicular to the propagation direction x. Meanwhile, between the two busbars 12a, electrode fingers 12b extending along the perpendicular direction y are arranged at predetermined intervals between adjacent electrode fingers 12b in the propagation direction x, thereby arranging a plurality of electrode fingers 12b side by side.

[0061] One comb electrode 12c is formed by one of the two busbars 12a and the electrode finger 12b connected thereto, and the other comb electrode 12c is formed by the other of the two busbars 12a and the electrode finger 12b connected thereto.

[0062] The two comb electrodes 12c are configured at any position in the propagation direction x such that an electrode finger 12b of the other comb electrode 12c is disposed between adjacent electrode fingers 12b of one comb electrode 12c, that is, they are configured to mesh with each other.

[0063] Furthermore, the reflector 11 has the following structure: two busbars 11a extending along the propagation direction x are arranged opposite each other at a predetermined interval in a perpendicular direction y, which is perpendicular to the propagation direction x. Meanwhile, between the two busbars 11a, electrode fingers 11b extending along the perpendicular direction y are arranged at predetermined intervals between adjacent electrode fingers 11b in the propagation direction x, thereby arranging multiple electrode fingers 11b side-by-side. Each electrode finger 11b spans between the two busbars 11a.

[0064] The forming region of the unit resonator 5 constructed as described above is substantially rectangular, and, as Figure 2 and Figure 4 As shown, the width W along the propagation direction x and the length L along the orthogonal direction y can be identified.

[0065] The electrode fingers 11b and 12b constituting the reflector 11 and IDT electrode 12 are arranged at any position in the propagation direction x in such a way that there is a substantially equal interval between adjacent electrode fingers 11b and 12b. This interval is determined by the wavelength of the elastic surface wave, which is the dominant mode.

[0066] Furthermore, the three or more unit resonators 5 in the propagation direction x include: at least one inner resonator 5a adjacent to the unit resonator 5 on both sides, and two outer resonators 5b adjacent to the unit resonator 5 as the inner resonator 5a on only one side.

[0067] In the first and second examples, gaps 13 are formed between the outer resonator 5b and the adjacent inner resonator 5a, and between the two inner resonators 5a, respectively, for accommodating the first portion of the parallel connection wiring 6 described later.

[0068] Furthermore, in the third to fifth examples, a gap 13 is formed between the outer resonator 5b and the inner resonator 5a to accommodate the first portion of the parallel connection wiring 6 described later.

[0069] On the other hand, the parallel connection wiring 6 has a first portion 6a extending along the propagation direction x and a second portion 6b extending along the orthogonal direction y.

[0070] The parallel connection wiring 6 consists of a wiring element 6c on one side and a wiring element 6d on the other side. The wiring element 6c on one side is directly or indirectly connected to one side of the input / output port 9, and the wiring element 6d on the other side is directly or indirectly connected to the other side of the input / output port 9.

[0071] Both wiring elements 6c and 6d have at least two first parts 6a and one second part 6b.

[0072] like Figure 2 As shown, the first portion 6a has a base 6e integrated with the second portion 6b, and an end portion 6f opposite to the base 6e.

[0073] The second part 6b is configured to span between the bases 6e of the two outermost first parts 6a located in the orthogonal direction y.

[0074] The second portion 6b of the wiring element 6c on one side and the second portion 6b of the wiring element 6d on the other side are spaced apart from each other and arranged opposite each other in the propagation direction x. The first portion 6a of the wiring element 6c on one side extends toward the second portion 6b of the wiring element 6d on the other side, and the first portion 6a of the wiring element 6d on the other side extends toward the second portion 6b of the wiring element 6c on one side.

[0075] Between the second portion 6b of the wiring element 6c on one side and the second portion 6b of the wiring element 6d on the other side, a spacing substantially equal to or slightly larger than the width W of the unit resonator 5 is provided in the propagation direction x. Each unit resonator 5 is formed between the second portions 6b of the two wiring elements 6c and 6d positioned as described above.

[0076] A gap is formed between the end 6f of the first portion 6a of the wiring element 6c on one side and the second portion 6b of the wiring element 6d on the other side, and between the end 6f of the first portion 6a of the wiring element 6d on the other side and the second portion 6b of the wiring element 6c on one side, and the gap is used to keep these portions in a non-contact state with each other.

[0077] At any position in the orthogonal direction y, the first portion 6a of the wiring element 6c on one side is adjacent to the first portion 6a of the wiring element 6d on the other side via the unit resonator 5, and simultaneously, the first portion 6a of the wiring element 6d on the other side is also adjacent to the first portion 6a of the wiring element 6c on one side via the unit resonator 5. That is, the wiring element 6c on one side and the wiring element 6d on the other side are configured in a mutually meshing manner with the unit resonator 5 present.

[0078] Each unit resonator 5 is located between the first part 6a of the wiring element 6c on one side and the first part 6a of the wiring element 6d on the other side.

[0079] like Figure 4As shown, the first part 6a of the wiring element 6c on one side is connected to the bus bar 12a of one comb electrode 12c of the IDT electrode 12 of each unit resonator 5, and the first part 6a of the wiring element 6d on the other side is connected to the bus bar 12a of the other comb electrode 12c of the IDT electrode 12 of each unit resonator 5.

[0080] Furthermore, the first portion 6a located between adjacent unit resonators 5 is configured to be simultaneously connected to the busbar 12a of each of the two adjacent unit resonators 5.

[0081] exist Figures 1 to 4 The first example shown and Figure 5 In the second example shown, the wiring element 6c on one side is located Figure 2 and Figure 5 On the upper side, and has three first parts 6a. That is, one side wiring element 6c has: located on the upper side. Figure 2 and Figure 5 The first portion 6a of the resonator 5b located on the outer side of the left side, the first portion 6a of the resonator 5b located on the outer side of the right side, and the first portion 6a of the gap 13 located between the two resonators 5a located on the inner side.

[0082] In addition, the wiring element 6d on the other side is located Figure 2 and Figure 5 On the lower side, and having two first portions 6a. That is, the wiring element 6d on the other side has: located on the lower side. Figure 2 and Figure 5 The first portion 6a of the gap 13 between the left outer resonator 5b and the adjacent inner resonator 5a, and located in Figure 2 and Figure 5 The first part 6a of the gap 13 between the right outer resonator 5b and the adjacent inner resonator 5a.

[0083] exist Figure 6 In the third example shown, the wiring element 6c on one side is located Figure 6 On the upper side, and having two first parts 6a. That is, one side wiring element 6c has: located on the upper side. Figure 6 The first portion 6a of the outer side of the right outer resonator 5b, and the first portion 6a of the gap 13 located between the left outer resonator 5b and the inner resonator 5a.

[0084] In addition, the wiring element 6d on the other side is located Figure 6 On the lower side, and having two first portions 6a. That is, the wiring element 6d on the other side has: located on the lower side. Figure 6The first portion 6a of the outer side of the left outer resonator 5b, and the first portion 6a of the gap 13 located between the right outer resonator 5b and the inner resonator 5a.

[0085] exist Figure 7 The fourth case shown and Figure 8 In the fifth example shown, one side wiring element 6c is located at Figure 7 and Figure 8 On the left side, and having two first parts 6a. That is, one side wiring element 6c has: located on the left side, and having two first parts 6a. Figure 7 and Figure 8 The first portion 6a of the outer side of the upper outer resonator 5b, and the first portion 6a of the gap 13 between the lower outer resonator 5b and the inner resonator 5a.

[0086] In addition, the wiring element 6d on the other side is located Figure 7 and Figure 8 On the right side, and having two first parts 6a. That is, the wiring element 6d on the other side has: located on the right side. Figure 7 and Figure 8 The first portion 6a of the outer side of the lower outer resonator 5b, and the first portion 6a of the gap 13 located between the upper outer resonator 5b and the inner resonator 5a.

[0087] like Figure 13 As shown, for example, the length L of the forming region of the resonator 102 is set as... Figure 12 The length L of the forming region of the resonator 102 shown is approximately half of the length of the region, and the width W of the forming region of the resonator 102 is set as... Figure 12 If the width W of the forming region of the resonator 102 shown is approximately twice that of the resonator, it can reduce the series resistance while forming a structure with the same characteristics as the resonator. Figure 12 The resonator 102 shown is a resonator 102 with the same performance.

[0088] However, for a resonator 3 with a significantly increased width W relative to the length L of the forming region, the layout freedom is reduced when the circuit pattern is laid out on the functional surface 2a.

[0089] If the segmented resonator 4 is configured as in this embodiment, multiple unit resonators 5 can be grouped together without reducing the length L of the forming region of the unit resonator 5, i.e., the length of the electrode finger 12b of the IDT electrode 12 constituting the unit resonator 5, while reducing the aforementioned layout freedom, thereby forming a configuration with... Figure 12 The resonator 102 shown is a split resonator 4 with the same performance.

[0090] More specifically, the forming region of the segmented resonator 4 is shaped into the following profile: relative to the outer contour line 4a along the propagation direction x (see... Figure 2 The outer contour line 4b along the orthogonal direction y will not increase or decrease significantly.

[0091] Furthermore, in this embodiment, the number of electrode fingers 11b, 12b constituting the unit resonator 5 is not equal to that of at least one unit resonator 5 and at least another unit resonator 5.

[0092] More specifically, the number of electrode fingers 11b and 12b constituting the unit resonator 5 is different from each other in all the unit resonators 5; Alternatively, the number of electrode fingers 11b, 12b constituting the unit resonator 5 may be unequal between at least one unit resonator 5 and at least another unit resonator 5, while the segmented resonator 4 may contain at least one group consisting of at least two unit resonators 5 with equal numbers of electrode fingers 11b, 12b.

[0093] That is, when the segmented resonator 4 is composed of three unit resonators 5, the segmented resonator 4 can be composed of two unit resonators 5 with the same number of electrode fingers 11b and 12b, and one unit resonator 5 with a different number of electrode fingers 11b and 12b than the aforementioned two unit resonators 5.

[0094] Furthermore, when the segmented resonator 4 is composed of four or more unit resonators 5, the segmented resonator 4 can also be configured to include at least one group consisting of unit resonators 5 that are distinguished by the number of electrode fingers 11b and 12b and are composed of an equal number of electrode fingers 11b and 12b.

[0095] like Figure 9 As shown, when the segmented resonator 4 is composed of unit resonators 5 of the same width W, and one end edge 5c of each unit resonator 5 along the orthogonal direction y is located on an imaginary first straight line L1 along the orthogonal direction y, while the other end edge 5d of each unit resonator 5 along the orthogonal direction y is located on an imaginary second straight line L2 along the orthogonal direction y, in the example shown, it is inevitable that the outer edge 6g of the second portion 6b of either the wiring element 6c on one side or the wiring element 6d on the other side (in the example, the outer edge 6g of the second portion 6b of the wiring element 6d on the other side) will be located outside the second straight line L2. On both sides of the second portion 6b configured in this way, a region that is difficult to utilize effectively due to its shape, namely the dead zone D, will be formed.

[0096] (Detailed composition of Example 1) exist Figures 1 to 4 In the first example shown, the electrodes 11b and 12b constituting the outer resonator 5b are positioned such that (see...) Figure 4 The number of electrodes 11b and 12b constituting the inner resonator 5a is greater than the number of electrodes 11b and 12b constituting the inner resonator 5a.

[0097] The width W of the forming region of the two outer resonators 5b is equal, that is, the number of electrode fingers 11b and 12b of the two outer resonators 5b is equal.

[0098] Furthermore, the width W of the forming region of the two inner resonators 5a is also equal, that is, the number of electrode fingers 11b and 12b of the two inner resonators 5a is equal.

[0099] On the other hand, the width W of the inner resonator 5a is smaller than the width W of the outer resonator 5b.

[0100] Furthermore, each unit resonator 5 is positioned on an imaginary first straight line L1 along one side edge 5c of the orthogonal direction y (i.e., the outer edge of the portion of one reflector 11 opposite to the side of the IDT electrode 12).

[0101] The other edge 5d of the two inner resonators 5a along the orthogonal direction y (i.e., the outer edge of the portion of the other reflector 11 opposite to the side of the IDT electrode 12) is located on the imaginary second straight line L2.

[0102] On the other hand, the other edge 5d of the two outer resonators 5b along the orthogonal direction y is located on an imaginary straight line L3 along the orthogonal direction y and outside the second straight line L2.

[0103] In the first example, the second part 6b of the wiring element 6d on the other side is formed such that its outer edge 6g is located on the straight line L3 by utilizing the distance between the second straight line L2 and the straight line L3.

[0104] That is, in the first example, a space is formed between the other end edge 5d of the resonator 5a arranged on the inner side along the orthogonal direction y and the straight line L3 for forming the second part 6b of the other side wiring element 6d as described above.

[0105] This configuration prevents the formation of the dead zone D, as described above, on functional surface 2a.

[0106] In the first example, the outer contour 4b of the forming region of the segmented resonator 4 along the orthogonal direction y is formed by the outer edge 6g of the second portion 6b of the wiring element 6c on one side, making it a straight line along the orthogonal direction y. Furthermore, the outer contour 4b of the forming region of the segmented resonator 4 along the orthogonal direction y is formed by the outer edge 6g of the second portion 6b of the wiring element 6d on the other side, and the other end edge 5d of the resonators 5a located on both sides of it, forming a straight line along the orthogonal direction y.

[0107] (Detailed composition of example 2) exist Figure 5 In the second example shown, the number of electrode fingers 11b and 12b constituting one of the two outer resonators 5b is less than the number of electrode fingers 11b and 12b constituting the inner resonator 5a. Simultaneously, the number of electrode fingers 11b and 12b constituting the other of the two outer resonators 5b is greater than the number of electrode fingers 11b and 12b constituting the inner resonator 5a. In the example shown, the width W of the right outer resonator 5b is greater than the width W of the two inner resonators 5a, while the width W of the left outer resonator 5b is less than the width W of the two inner resonators 5a.

[0108] Furthermore, the left outer resonator 5b has its side edge 5c along the orthogonal direction y located on an imaginary first straight line L1, and its other side edge 5d along the orthogonal direction y located on an imaginary second straight line L2. On the other hand, the right outer resonator 5b has its side edge 5c along the orthogonal direction y located on a straight line L3 outside the first straight line L1, and its other side edge 5d along the orthogonal direction y located on a straight line L4 outside the second straight line L2. The two inner resonators 5a have their side edges 5c along the orthogonal direction y located between the first straight line L1 and the straight line L3, and their other side edges 5d along the orthogonal direction y located between the second straight line L2 and the straight line L4. In the second example, using the distance between the second straight line L2 and the straight line L4, the second part 6b of the wiring element 6d on the other side is formed such that its outer edge 6g is located on the straight line L4.

[0109] The width W of the unit resonator 5 gradually decreases in the order of right outer resonator 5b, right inner resonator 5a, left inner resonator 5a, and left outer resonator 5b. In this second example, the number of electrode fingers 11b and 12b constituting the unit resonator 5 is different for each of the unit resonators 5. By configuring it in this way, the dead zone D as described above can be prevented from being generated on the functional surface 2a. That is, in the second example, a space is formed between the other end edge 5d of the inner resonator 5a along the orthogonal direction y and the other end edge 5d of the left outer resonator 5b along the orthogonal direction y and the straight line L4 for forming the second part 6b of the other side wiring element 6d as described above.

[0110] In the second example, the outer contour 4b of the forming region of the segmented resonator 4 along the orthogonal direction y is formed by the outer edge 6g of the second portion 6b of the wiring element 6c on one side, making it a straight line along the orthogonal direction y. Furthermore, the outer contour 4b of the forming region of the segmented resonator 4 along the orthogonal direction y is formed by the outer edge 6g of the second portion 6b of the wiring element 6d on the other side, and the other end edge 5d of the resonator 5b arranged on the right outer side along the orthogonal direction y, making it a straight line along the orthogonal direction y.

[0111] Meanwhile, in this second example, by utilizing the distance between the first straight line L1 and the straight line L3, and the distance between the second straight line L2 and the straight line L4, the width of the second part 6b is made wider in a local area relative to the first part 6a, thereby increasing the Q value by reducing the resistance.

[0112] Specifically, in the second example, both the wiring element 6c on one side and the wiring element 6d on the other side are in Figure 5 The left side is connected to the input / output port 9, and using the aforementioned distance, the width of the second part 6b gradually increases along the connection side direction toward the input / output port 9.

[0113] (Detailed composition of case 3) exist Figure 6 In the third example shown, the number of electrode fingers 11b and 12b constituting the two outer resonators 5b is greater than the number of electrode fingers 11b and 12b constituting the inner resonator 5a.

[0114] The width W of the forming region of the two outer resonators 5b is equal, and the width W of the inner resonator 5a is smaller than the width W of the outer resonator 5b.

[0115] Furthermore, the right outer resonator 5b has its side edge 5c along the orthogonal direction y on one side, and the inner resonator 5a has its side edge 5c along the orthogonal direction y on one side, located on an imaginary first straight line L1. Meanwhile, the left outer resonator 5b has its side edge 5c along the orthogonal direction y on one side, located on an imaginary straight line L3 outside the first straight line L1.

[0116] Furthermore, the other end edge 5d of the resonator 5b on the left outer side along the orthogonal direction y and the other end edge 5d of the resonator 5a on the inner side along the orthogonal direction y are located on the imaginary second straight line L2, while the other end edge 5d of the resonator 5b on the right outer side along the orthogonal direction y is located on the imaginary straight line L4 outside the second straight line L2.

[0117] In the third example, the second portion 6b is formed such that its outer edge 6g is located on the lines L3 and L4, using the distance between the first line L1 and the line L3, and the distance between the second line L2 and the line L4.

[0118] This configuration prevents the formation of the dead zone D, as described above, on functional surface 2a.

[0119] That is, in the third example, a space is formed between the inner side of the resonator 5a along the orthogonal direction y and the outer side of the right side of the resonator 5b along the orthogonal direction y and the straight line L3, for forming the second part 6b of the wiring element 6c as described above.

[0120] Meanwhile, between the inner side resonator 5a and the outer left side resonator 5b along the orthogonal direction y, and the straight line L4, a space is formed for forming the second part 6b of the other side wiring element 6d as described above.

[0121] In the third example, the outer contour 4b of the forming region of the segmented resonator 4 along the orthogonal direction y is formed by the outer edge 6g of the second portion 6b of the wiring element 6c on one side and the end edge 5c of the resonator 5b on the left outer side along the orthogonal direction y, forming a straight line along the orthogonal direction y. Furthermore, the outer contour 4b of the forming region of the segmented resonator 4 along the orthogonal direction y is formed by the outer edge 6g of the second portion 6b of the wiring element 6d on the other side and the end edge 5d of the resonator 5b on the right outer side along the orthogonal direction y, forming a straight line along the orthogonal direction y.

[0122] (Detailed composition of case 4) exist Figure 7 In the fourth example shown, the number of electrode fingers 11b and 12b constituting the two outer resonators 5b is greater than the number of electrode fingers 11b and 12b constituting the inner resonator 5a.

[0123] The width W of the forming region of the two outer resonators 5b is equal, and the width W of the inner resonator 5a is smaller than the width W of the outer resonator 5b.

[0124] Furthermore, the upper outer resonator 5b has its side edge 5c along the orthogonal direction y on one side, and the inner resonator 5a has its side edge 5c along the orthogonal direction y on one side, located on an imaginary first straight line L1. Meanwhile, the lower outer resonator 5b has its side edge 5c along the orthogonal direction y on one side, located on an imaginary straight line L3 outside the first straight line L1.

[0125] Furthermore, the other end edge 5d of the lower outer resonator 5b along the orthogonal direction y and the other end edge 5d of the inner resonator 5a along the orthogonal direction y are located on an imaginary second straight line L2, while the other end edge 5d of the upper outer resonator 5b along the orthogonal direction y is located on an imaginary straight line L4 outside the second straight line L2.

[0126] In the fourth example, the second part 6b is formed such that its outer edge 6g is located on the lines L3 and L4, using the distance between the first line L1 and the line L3, and the distance between the second line L2 and the line L4.

[0127] This configuration prevents the formation of the dead zone D, as described above, on functional surface 2a.

[0128] That is, in the fourth example, a space is formed between the inner side of the resonator 5a along the orthogonal direction y and the upper outer side of the resonator 5b along the orthogonal direction y and the straight line L3, for forming the second part 6b of the wiring element 6c as described above.

[0129] Meanwhile, between the inner side resonator 5a and the lower outer side resonator 5b along the orthogonal direction y, and the straight line L4, a space is formed for forming the second part 6b of the other side wiring element 6d as described above.

[0130] Furthermore, in this fourth example, the distance is used to make the width of the second portion 6b wider than that of the first portion 6a, thereby increasing the Q value by reducing the resistance.

[0131] In the fourth example, the outer contour 4b of the forming region of the segmented resonator 4 along the orthogonal direction y is formed by the outer edge 6g of the second part 6b of the wiring element 6c on one side and the end edge 5c of the resonator 5b arranged on the lower outer side along the orthogonal direction y, forming a straight line along the orthogonal direction y.

[0132] Furthermore, the outer contour 4b of the forming region of the segmented resonator 4 along the other side of the orthogonal direction y is formed by the outer edge 6g of the second part 6b of the wiring element 6d on the other side, and the other end edge 5d of the upper outer resonator 5b along the orthogonal direction y, forming a straight line along the orthogonal direction y.

[0133] (Detailed composition of case 5) exist Figure 8 In the fifth example shown, the parallel connection wiring 6 is configured as follows: a first portion 6a located between adjacent unit resonators 5 in the orthogonal direction y, and a first portion 6a located outside the resonator 5b arranged on the outside, the width of which is larger on the base 6e side integrated with the second portion 6b, and smaller on the opposite end 6f side.

[0134] In the example shown, the first portion 6a has a shape in which its width gradually increases from the end 6f towards the base 6e. To achieve this variation in the width of the first portion 6a, the contours of each unit resonator 5 are shaped accordingly. As a result, the resistance of the first portion 6a decreases as it approaches the input / output port 9, thereby increasing the Q value.

[0135] The first part 6a can also be configured as a shape in which the width gradually increases from the end 6f toward the base 6e, that is, forming a tapered structure with a narrower end 6f.

[0136] Furthermore, the structure of the first part 6a in the fifth example above can also be applied to examples 1 through 4.

[0137] The remaining components of Example 5 are substantially the same as those of Example 4. For substantially identical components, in Figure 8 Chinese annotation and Figure 7 The descriptions of the same symbols are omitted here.

[0138] The segmented resonator 4 described above is formed in a region consisting of an imaginary straight line along the orthogonal direction y and defined between a pair of straight lines arranged opposite each other in the propagation direction x.

[0139] Meanwhile, the segmented resonator 4 is formed by configuring the unit resonator 5 and the parallel connection wiring 6 in the forming region, such that on at least one of the pair of straight lines, one of the end edges 5c and 5d of at least one of the unit resonators 5 along the orthogonal direction y, and the outer edge 6g of the second portion 6b of the parallel connection wiring 6 facing outward from the forming region are both inscribed in the straight line, thereby filling the forming region with almost no gaps between the unit resonator 5 and the parallel connection wiring 6.

[0140] That is, in this embodiment, by utilizing the space created by not setting the width W of the unit resonator 5 to be constant, at least one side of the two outer contour lines 4b along the orthogonal direction y in the forming region of the segmented resonator 4 is formed into a straight line by the outer edge 6g of the second part 6b of either the wiring element 6c on one side or the wiring element 6d on the other side, and one of the end edges 5c and 5d of the unit resonator 5 along the orthogonal direction y.

[0141] Thus, the segmented resonator 4 is formed on the functional surface 2a with the pair of straight lines serving as the outer contour lines 4b respectively, without generating the dead zone D.

[0142] Typically, the device chip 2 has a side length of 0.5 to 1 mm and a thickness of 0.15 to 0.2 mm.

[0143] Furthermore, the conductive metal layer constituting the unit resonator 5 is typically made of aluminum or an aluminum-based alloy, and its thickness is typically 0.1 to 0.4 μm.

[0144] Furthermore, the width W of the unit resonator 5 is typically 200 to 400 μm, and the length L of the unit resonator 5 is typically 50 to 100 μm.

[0145] Furthermore, the conductive metal layer constituting the parallel connection wiring 6 is typically made of aluminum or an aluminum-based alloy, and its thickness is typically 2 to 4 μm.

[0146] Furthermore, the width of the parallel connection wiring 6 is typically 10 to 30 μm.

[0147] It should be noted that, in the accompanying drawings, the thickness of the constituent elements, etc., have been appropriately exaggerated to facilitate understanding of the structure of the elastic wave device 1.

[0148] Of course, the present invention is not limited to the embodiments described above, but includes all embodiments that can achieve the purpose of the present invention.

Claims

1. An elastic wave device, characterized in that: The elastic wave device is formed by forming a circuit pattern including a resonator with IDT electrodes on the functional surface of a device chip, where at least one side is a functional surface made of piezoelectric material. In this circuit pattern, at least one of the resonators is a segmented resonator, which is formed by connecting at least three unit resonators, each functioning as a resonator, in parallel using wiring. The unit resonators are arranged in parallel along a direction perpendicular to the propagation direction of the elastic surface wave excited by the IDT electrodes. The parallel connection wiring has a first portion extending along the propagation direction and a second portion extending along the orthogonal direction. Furthermore, the number of electrode fingers constituting the unit resonator is not equal between at least one unit resonator and at least another unit resonator.

2. The elastic wave device according to claim 1, characterized in that, The elastic wave device is formed by forming a circuit pattern including a resonator with IDT electrodes on the functional surface of a device chip, where at least one side is a functional surface made of piezoelectric material. In this circuit pattern, at least one of the resonators is a segmented resonator, which is formed by connecting at least three unit resonators, each functioning as a resonator, in parallel using wiring. The unit resonators are arranged in parallel along a direction perpendicular to the propagation direction of the elastic surface wave excited by the IDT electrodes. The parallel connection wiring has a first portion extending along the propagation direction and a second portion extending along the orthogonal direction. Furthermore, the number of electrode fingers constituting the unit resonator differs from one another in all the unit resonators. Alternatively, the number of electrode fingers constituting the unit resonator is not equal between at least one unit resonator and at least another unit resonator, while the split resonator includes at least two unit resonators with an equal number of electrode fingers.

3. The elastic wave device according to claim 1 or 2, characterized in that, The three or more unit resonators include, in the propagation direction: At least one resonator is disposed on the inner side of the unit resonator adjacent to each of its two sides, and Two resonators, arranged on the outer side of the unit resonator (which is the inner resonator), are adjacent only on one side. Furthermore, the number of electrode fingers constituting at least one of the outer resonators is greater than the number of electrode fingers of the adjacent inner resonators.

4. The elastic wave device according to claim 1 or 2, characterized in that, The three or more unit resonators include, in the propagation direction: At least one resonator is disposed on the inner side of the unit resonator adjacent to each of its two sides, and Two resonators, arranged on the outer side of the unit resonator (which is the inner resonator), are adjacent only on one side. In one case, the number of electrode fingers constituting the outer resonator is greater than the number of electrode fingers constituting the inner resonator. Furthermore, the number of electrode fingers formed by the outer resonator of the other party is less than the number of electrode fingers formed by the inner resonator adjacent to it.

5. The elastic wave device according to claim 1 or 2, characterized in that, The width of the first portion of the parallel connection wiring is larger on the base side integrated with the second portion and smaller on the opposite end side.

6. The elastic wave device according to claim 1 or 2, characterized in that, The wiring for the parallel connection includes: A side wiring element having the first part and the second part, and Having wiring elements on the other side of the first part and the second part, In the propagation direction, the second portions of the two wiring elements are spaced apart from each other and arranged relative to each other. Furthermore, in the orthogonal direction, the first portion of the wiring element on one side is adjacent to the first portion of the wiring element on the other side, separated from the unit resonator by the unit resonator; simultaneously, the first portion of the wiring element on the other side is adjacent to the first portion of the wiring element on one side, separated from the unit resonator by the unit resonator. This allows the wiring elements on one side to be configured in an interlocking manner with the wiring elements on the other side.

7. The elastic wave device according to claim 5, characterized in that, In the formation region of the segmented resonator, at least one side of the outer contour line along the orthogonal direction is formed by the outer edge of the second part of either the one-side wiring element or the other-side wiring element, which together with the end edge of the unit resonator along the orthogonal direction forms a straight line.

8. The elastic wave device according to claim 1, characterized in that, The width of the unit resonator is 200 to 400 μm, and its length is 50 to 100 μm.

9. The elastic wave device according to claim 1, characterized in that, The width of the wiring used for the parallel connection is 10 to 30 μm.

10. The elastic wave device according to claim 1, characterized in that, The unit resonator and the conductive metal layer of the parallel connection wiring are made of aluminum or an alloy mainly composed of aluminum.

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