JP2016201780A - Elastic wave device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic device that is able to improve reliability.SOLUTION: An elastic wave device comprises: a substrate 30 having on its principal surface at least one of a relay electrode 46 and a sealing metal layer 50, and provided on the bottom face of a recessed part 52 or the top face of a projecting part 54, which has at least one of the relay electrode 46 and sealing metal layer 50 formed on the principal surface; and a substrate 10 having at least one of an element electrode 20 and sealing metal layer 22 electrically connected to IDT 12 and IDT 12, which excite an elastic wave to the principal surface, and mounted on the substrate 30 having a gap 64 from which the IDT 12 is exposed between this substrate and the substrate 30 as a result of the element electrode 20 having been joined to the relay electrode 46 by solder and/or the sealing metal layer 22 having been joined to the sealing metal layer 50 by solder so as to seal the IDT 12.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an acoustic wave device.

  There is known an acoustic wave device in which a plurality of acoustic wave chips are flip-chip mounted on a substrate, and the plurality of acoustic wave chips are sealed with a resin (for example, see Patent Document 1). In addition, one substrate provided with a functional portion for exciting elastic waves and the other substrate provided with a functional portion for exciting elastic waves are joined so that the respective functional portions are opposed to each other. An acoustic wave device in which a portion is sealed with a sealing portion is known (see, for example, Patent Document 2).

JP 2010-28639 A JP 2008-113178 A

  A substrate provided with an electrode and a sealing metal layer on the main surface, a functional portion on the main surface, and a substrate provided with an electrode electrically connected to the functional portion and the sealing metal layer. In an acoustic wave device in which electrodes and sealing metal layers are joined by solder, the solder may be formed so as to protrude from a predetermined region. In this case, there is a concern about reliability because it may adversely affect characteristics and the like.

  SUMMARY An advantage of some aspects of the invention is that it provides an electronic device capable of improving reliability.

  The present invention has at least one of a first electrode and a first sealing metal layer on a main surface, and at least one of the first electrode and the first sealing metal layer is a bottom surface of a recess formed on the main surface. Alternatively, the first substrate provided on the upper surface of the convex portion, the first functional portion for exciting the elastic wave on the main surface, and the second electrode and the second sealing metal layer electrically connected to the first functional portion At least one of the first electrode and the second electrode is joined to the first electrode by soldering and / or the first sealing metal layer seals the first functional part. A second substrate mounted on the first substrate with a gap exposing the first functional part between the first substrate and being bonded to the sealing metal layer. The elastic wave device is characterized. According to the present invention, reliability can be improved.

  In the above configuration, the first substrate has both the first electrode and the first sealing metal layer, and the second substrate has both the second electrode and the second sealing metal layer. The second electrode may be joined to the first electrode by solder and the second sealing metal layer may be joined to the first sealing metal layer by solder.

  The said structure WHEREIN: Both said 1st electrode and said 1st sealing metal layer can be set as the structure provided in the bottom face of the said recessed part, or the upper surface of the said convex part.

  In the above configuration, a configuration is provided that includes a metal film that surrounds the stacked body of the first sealing metal layer and the second sealing metal layer, covers the exposed surface of the stacked body, and has a higher melting point than solder. It can be.

  In the above configuration, the second substrate may be a piezoelectric substrate, and the first functional unit may be an IDT.

  The said structure WHEREIN: It can be set as the structure provided with the 2nd functional part which excites the elastic wave provided in the said main surface other than the said recessed part or the said convex part of the said 1st board | substrate, exposed to the said space | gap.

  In the above configuration, the second functional part may be a region where the upper electrode, the piezoelectric thin film, and the lower electrode of the piezoelectric thin film resonator overlap.

  In the above configuration, the first substrate may be a silicon substrate.

  According to the present invention, reliability can be improved.

1A is a plan view of one substrate included in the acoustic wave device according to the first embodiment, and FIG. 1B is a plan view of the other substrate included in the acoustic wave device according to the first embodiment. FIG. 3C is a plan view of the acoustic wave device according to the first embodiment. FIG. 2 is a cross-sectional view of the piezoelectric thin film resonator. FIG. 3 is a cross-sectional view taken along the line AA in FIG. FIG. 4 is a perspective view of the acoustic wave device according to the first embodiment. FIG. 5A to FIG. 5D are cross-sectional views (part 1) illustrating the method for manufacturing the acoustic wave device according to the first embodiment. 6A to 6C are cross-sectional views (part 2) illustrating the method for manufacturing the acoustic wave device according to the first embodiment. FIG. 7A and FIG. 7B are cross-sectional views of modified examples of the recesses. FIG. 8 is a cross-sectional view of the acoustic wave device according to the second embodiment. FIG. 9A to FIG. 9E are cross-sectional views of modified examples of the convex portions.

  Embodiments of the present invention will be described below with reference to the drawings.

  1A is a plan view of one substrate 10 provided in the acoustic wave device 100 according to the first embodiment, and FIG. 1B is a plan view of the other substrate 30 provided in the acoustic wave device 100 according to the first embodiment. FIG. 1C is a plan view of the acoustic wave device 100 according to the first embodiment. In FIGS. 1A to 1C, the configuration is simplified for the sake of clarity. In FIG. 1C, the acoustic wave element 16 and the piezoelectric thin film resonator 32 are illustrated through the substrate 10, and the components provided on the main surface of the substrate 10 are indicated by solid lines and the main surface of the substrate 30. The components provided in are shown by broken lines.

  As shown in FIG. 1A, the substrate 10 provided in the acoustic wave device 100 of the first embodiment has an IDT (Interdigital Transducer) 12 and a reflector 14 formed on the main surface. The substrate 10 is a piezoelectric substrate, for example, a lithium tantalate substrate or a lithium niobate substrate. The IDT 12 is a functional unit that excites an elastic wave in or on the substrate 10. The reflector 14 reflects elastic waves. The IDT 12 and the reflector 14 form an acoustic wave element 16 such as a resonator. The IDT 12 and the reflector 14 are metal films such as an aluminum film, a copper film, or an aluminum film to which copper is added.

  On the main surface of the substrate 10, wirings 18 and element electrodes 20 are formed. The wiring 18 electrically connects the acoustic wave elements 16 and / or the acoustic wave element 16 and the element electrode 20. The wiring 18 is a metal film in which, for example, a titanium film and a gold film are laminated from below. The element electrode 20 is a metal pillar such as a copper pillar, for example.

  The plurality of acoustic wave elements 16 formed on the main surface of the substrate 10 are connected in series via the wiring 18 between the input electrode IN and the output electrode OUT. The acoustic wave element 16 is electrically connected to the ground electrode GND through the wiring 18.

  A sealing metal layer 22 is formed on the main surface of the substrate 10. The sealing metal layer 22 is formed on the outer peripheral portion of the substrate 10 so as to collectively surround the plurality of acoustic wave elements 16, the wirings 18, and the element electrodes 20. The sealing metal layer 22 is a columnar metal layer such as copper.

  As shown in FIG. 1B, the substrate 30 provided in the acoustic wave device 100 of Example 1 has a piezoelectric thin film resonator 32 formed on the main surface. The substrate 30 is, for example, a silicon substrate. Here, the piezoelectric thin film resonator 32 will be described. FIG. 2 is a cross-sectional view of the piezoelectric thin film resonator 32. As shown in FIG. 2, the piezoelectric thin film resonator 32 has a lower electrode 34, a piezoelectric thin film 36, and an upper electrode 38 stacked in this order on a substrate 30. The lower electrode 34 is provided on the substrate 30 such that a gap 42 having a dome-like bulge is formed between the lower electrode 34 and the substrate 30. The dome-shaped bulge is, for example, a bulge having a shape in which the height of the gap 42 is low around the gap 42 and the height of the gap 42 is increased toward the center of the gap 42. The lower electrode 34 and the upper electrode 38 are, for example, a metal single layer film such as aluminum, copper, chromium, molybdenum, tungsten, tantalum, titanium, platinum, ruthenium, rhodium, or iridium, or a laminated film thereof. The piezoelectric thin film 36 is, for example, an aluminum nitride film, a zinc oxide film, a lead zirconate titanate film, or a lead titanate film.

  A region where the lower electrode 34 and the upper electrode 38 overlap with each other with the piezoelectric thin film 36 therebetween becomes a resonance region 40. The resonance region 40 has an elliptical shape, for example. In the resonance region 40, an elastic wave (bulk wave of thickness longitudinal vibration) propagating in the vertical direction excited in the piezoelectric thin film 36 resonates. That is, a region where the lower electrode 34, the piezoelectric thin film 36, and the upper electrode 38 overlap (resonance region 40) is a functional unit that excites an elastic wave. In place of the dome-shaped gap 42 formed between the substrate 30 and the lower electrode 34, a recess provided in the substrate 30 may be used as the gap 42. The recess may penetrate the substrate 30 or may not penetrate. Further, an acoustic reflection film that reflects elastic waves may be formed instead of the gap 42.

  As shown in FIG. 1B, wirings 44, relay electrodes 46, and element electrodes 48 are formed on the main surface of the substrate 30. The wiring 44 electrically connects the piezoelectric thin film resonators 32 and / or the piezoelectric thin film resonator 32 and the element electrode 48. The relay electrode 46 is not connected to the wiring 44 and is not electrically connected to the piezoelectric thin film resonator 32 and the element electrode 48. The wiring 44, the relay electrode 46, and the element electrode 48 are metal layers in which, for example, a titanium film and a gold film are laminated from below.

  The plurality of piezoelectric thin film resonators 32 formed on the main surface of the substrate 30 are connected in series via the wiring 44 between the input electrode IN and the output electrode OUT. The piezoelectric thin film resonator 32 is electrically connected to the ground electrode GND through the wiring 44.

  A sealing metal layer 50 is formed on the main surface of the substrate 30. The sealing metal layer 50 is formed on the outer periphery of the substrate 30 so as to collectively surround the plurality of piezoelectric thin film resonators 32, the wiring 44, the relay electrode 46, and the element electrode 48. The sealing metal layer 50 is a metal layer in which, for example, a titanium film and a gold film are stacked from below.

  As shown in FIG. 1C, the acoustic wave device 100 according to the first embodiment is configured such that the element electrode 20 of the substrate 10 is joined to the relay electrode 46 of the substrate 30 by solder (not shown), and the sealing metal layer of the substrate 10 22 is joined to the sealing metal layer 50 of the substrate 30 by solder (not shown). Thereby, the substrate 10 is mounted on the substrate 30. The acoustic wave element 16 on the substrate 10 and the piezoelectric thin film resonator 32 on the substrate 30 are arranged to face each other.

  FIG. 3 is a cross-sectional view taken along the line AA in FIG. FIG. 4 is a perspective view of the acoustic wave device 100 according to the first embodiment. In FIG. 3, the acoustic wave element 16 and the piezoelectric thin film resonator 32 are illustrated in a simplified manner. As shown in FIG. 3, the main surface of the substrate 10 is flat, and the acoustic wave element 16, the wiring 18 (not shown in FIG. 3), the element electrode 20, and the sealing metal layer 22 are flat main surfaces of the substrate 10. Is provided. The height of the element electrode 20 and the sealing metal layer 22 is, for example, about 8 μm to 12 μm.

  On the other hand, a recess 52 is formed in the main surface of the substrate 30. The depth D of the recess 52 is, for example, about 3 μm to 7 μm. The depth of each of the plurality of recesses 52 is approximately the same. The piezoelectric thin film resonator 32 and the wiring 44 (not shown in FIG. 3) are provided in a region other than the concave portion 52 on the main surface of the substrate 30. The relay electrode 46, the element electrode 48, and the sealing metal layer 50 are provided on the bottom surface of the recess 52 of the substrate 30. The surface (upper surface) of the relay electrode 46, the element electrode 48, and the sealing metal layer 50 is lower than the region other than the concave portion 52 on the main surface of the substrate 30. The minimum distance L between the recess 52 in which the relay electrode 46 is formed, the piezoelectric thin film resonator 32, and the wiring 44 (not shown in FIG. 3) is, for example, 3 μm to 7 μm.

  Internal wiring 56 connected to the relay electrode 46 and the element electrode 48 is formed inside the substrate 30. A foot pad 58 connected to the internal wiring 56 is formed on the main surface of the substrate 30 opposite to the main surface on which the piezoelectric thin film resonator 32 and the like are formed. The foot pad 58 is a terminal connected to an external device.

  The element electrode 20 on the substrate 10 and the relay electrode 46 on the substrate 30 are joined by solder 60. Further, the sealing metal layer 22 of the substrate 10 and the sealing metal layer 50 of the substrate 30 are joined by solder 62. The solders 60 and 62 are, for example, tin-silver solder. Thereby, the board | substrate 10 and the board | substrate 30 have the space | gap 64 between them, and are joined. The height H of the gap 64 is, for example, 3 μm to 7 μm. In consideration of the strain due to the stress of the substrate 10 and the substrate 30, the height H of the gap 64 may be about several tens of μm (for example, about 20 μm to 40 μm).

  The acoustic wave element 16 and the wiring 18 formed on the substrate 10 and the piezoelectric thin film resonator 32 and the wiring 44 formed on the substrate 30 are exposed in the gap 64. Since the acoustic wave element 16 and the piezoelectric thin film resonator 32 are exposed to the gap 64, the vibration of the acoustic wave element 16 and the piezoelectric thin film resonator 32 is prevented from being hindered. The acoustic wave element 16, the piezoelectric thin film resonator 32, the wirings 18 and 44, the element electrodes 20 and 48, and the relay electrode 46 are hermetically sealed by the sealing metal layer 22 and the sealing metal layer 50. A metal film 66 made of a metal having a melting point higher than that of the solder 62 (for example, a nickel plating film) is formed on the exposed surface of the laminate of the sealing metal layer 22 and the sealing metal layer 50. As shown in FIG. 4, the metal film 66 is provided so as to surround the substrate 10 (that is, surround the sealing metal layer 22 and the sealing metal layer 50).

  Next, a method for manufacturing the acoustic wave device 100 according to the first embodiment will be described. FIG. 5A to FIG. 6C are cross-sectional views illustrating a method for manufacturing the acoustic wave device 100 according to the first embodiment. FIGS. 5A to 6C show a manufacturing method using a multi-chamfer process. 5 (a) and 5 (b) are cross-sectional views showing the manufacturing method on the substrate 10 side, and FIGS. 5 (c) and 5 (d) are cross-sectional views showing the manufacturing method on the substrate 30 side. FIG. The manufacturing process of FIGS. 5A and 5B and the manufacturing process of FIGS. 5C and 5D are performed separately (for example, in parallel).

  First, a manufacturing method on the substrate 10 side will be described. As shown in FIG. 5A, on the substrate 10, an acoustic wave element 16 composed of an IDT and a reflector made of a metal film, a wiring 18 made of a metal film (not shown in FIG. 5A), Form. The metal film can be formed by sputtering or vapor deposition, and the pattern can be formed by etching or lift-off. Further, the element electrode 20 and the sealing metal layer 22 are formed on the substrate 10. The element electrode 20 and the sealing metal layer 22 can be formed by a plating method.

  As shown in FIG. 5B, a dicing tape 70 is attached to the main surface of the substrate 10 opposite to the main surface on which the acoustic wave element 16 and the like are formed. Thereafter, the substrate 10 is cut by dicing using a dicing blade 72 to be separated into a plurality of chips 74.

  Next, a manufacturing method on the substrate 30 side will be described. As shown in FIG. 5C, the recess 52 and the hole 76 formed in the substrate 30 connected to the bottom surface of the recess 52 are formed on the main surface of the substrate 30. The recess 52 and the hole 76 can be formed by an etching method, a laser method, or a blast method.

  As shown in FIG. 5D, the piezoelectric thin film resonator 32 and the wiring 44 (not shown in FIG. 5D) are formed in a region other than the recess 52 on the main surface of the substrate 30. The relay electrode 46, the element electrode 48, and the sealing metal layer 50 are formed in the recess 52. Internal wiring 56 is formed in the hole 76. A foot pad 58 connected to the internal wiring 56 is formed on the main surface opposite to the main surface on which the recess 52 of the substrate 30 is formed. The relay electrode 46, the element electrode 48, the sealing metal layer 50, the internal wiring 56, and the foot pad 58 can be formed by sputtering or evaporation, and the pattern can be formed by etching or lift-off. .

  After performing the manufacturing process of FIG. 5A to FIG. 5D, the chip 74 is temporarily mounted on the main surface of the substrate 30 where the recess 52 is formed, as shown in FIG. 6A. Specifically, the solder 60 is formed on the upper surface (lower surface in FIG. 6A) of the element electrode 20 of the substrate 10, and on the upper surface (lower surface in FIG. 6A) of the substrate 10. After forming the solder 62, the solder 60 is disposed on the relay electrode 46 of the substrate 30, and the solder 62 is disposed on the sealing metal layer 50 of the substrate 30. Note that the wafer-like substrate 10 may be temporarily mounted on the main surface of the substrate 30 without performing the process of dividing into chips 74 in FIG. 5B, but considering the warpage of the substrate, the chip 74 is preferably temporarily mounted.

  As shown in FIG. 6B, after a plurality of chips 74 are temporarily mounted on the main surface of the substrate 30, the solders 60 and 62 are melted, and the plurality of chips 74 are moved to the substrate 30 side using a metal plate 78 or the like. Press on. Thereby, the element electrode 20 and the relay electrode 46 are joined by the solder 60. The sealing metal layer 22 and the sealing metal layer 50 are joined by the solder 62. Further, the acoustic wave element 16 and the piezoelectric thin film resonator 32 are exposed to a gap 64 formed between the substrate 10 and the substrate 30 and are hermetically sealed by the sealing metal layer 22 and the sealing metal layer 50. .

  As shown in FIG. 6C, the dicing tape 80 is attached to the main surface of the substrate 30 on which the foot pads 58 are formed. Thereafter, a metal film 66 is formed on the exposed surfaces of the sealing metal layer 22 and the sealing metal layer 50 on the wafer-like substrate 30 by using an electrolytic plating method. At this time, since the foot pad 58 is covered with the dicing tape 80, plating is not performed. Thereafter, the substrate 30 is cut by dicing using the dicing blade 72, so that the plurality of acoustic wave devices 100 are separated. The elastic wave device 100 of Example 1 is formed including such a manufacturing process.

  According to the first embodiment, as shown in FIG. 3, the relay electrode 46 to which the element electrode 20 of the substrate 10 is joined by the solder 60 is provided on the bottom surface of the recess 52 formed in the substrate 30. Thereby, the distance between the relay electrode 46 and the piezoelectric thin film resonator 32, the wiring 44, and the sealing metal layer 50 can be lengthened. Similarly, the sealing metal layer 50 to which the sealing metal layer 22 of the substrate 10 is joined by the solder 62 is provided on the bottom surface of the recess 52 formed in the substrate 30. Accordingly, the distance between the sealing metal layer 50 and the piezoelectric thin film resonator 32, the relay electrode 46, the element electrode 48, and the wiring 44 can be increased. Therefore, even when the solders 60 and 62 are formed wider than a predetermined region by melting and pressing in FIG. 6B, the solders 60 and 62 are prevented from coming into contact with the piezoelectric thin film resonator 32, the wiring 44, and the like. Reliability can be improved.

  Further, according to Example 1, as shown in FIGS. 3 and 4, the laminated body of the sealing metal layer 22 and the sealing metal layer 50 is surrounded, and the exposed surface of the laminated body has a melting point higher than that of the solder 62. A high metal film 66 is provided. Thereby, even when the elastic wave device 100 is mounted on the mounting substrate and the solder 62 is remelted, it is possible to prevent the airtightness of the gap 64 from being lowered. The metal film 66 is preferably a metal having good moisture resistance, and for example, is preferably a metal having better moisture resistance than the sealing metal layers 22 and 50.

  In Example 1, since the substrate 30 is a silicon substrate, the recess 52 can be easily formed.

  In the first embodiment, as shown in FIG. 3, the acoustic wave element 16 including the IDT 12 that excites the elastic wave is formed on the main surface of the substrate 10, and the piezoelectric thin film resonator that excites the elastic wave on the main surface of the substrate 30. 32 is formed. Thereby, a small acoustic wave device 100 having a plurality of acoustic wave elements is obtained. From the viewpoint of miniaturization, it is preferable that the acoustic wave element 16 and the piezoelectric thin film resonator 32 are disposed so as to be opposed to each other.

  Moreover, according to Example 1, the depth of the recessed part 52 in which each of the relay electrode 46 and the sealing metal layer 50 is formed is the same. Therefore, it is easy to prevent the solders 60 and 62 from coming into contact with the piezoelectric thin film resonator 32, the wiring 44, and the like over the entire main surface of the substrate 30. Moreover, the recessed part 52 can be easily formed because the depth of each of the several recessed part 52 is the same.

  In the first embodiment, the depth of the recess 52 in which the relay electrode 46 is formed is suppressed from the point of suppressing the inflow of the solder 60 to the components (for example, the piezoelectric thin film resonator 32) formed on the main surface of the substrate 30. The length is preferably 1.0 times or more of the minimum distance between the concave portion 52 and the component, more preferably 2.0 times or more, and further preferably 3.0 times or more. Similarly, the depth of the recess 52 in which the sealing metal layer 50 is formed is determined from the point of suppressing the inflow of the solder 62 to the component (for example, the piezoelectric thin film resonator 32) formed on the main surface of the substrate 30. The minimum distance between the recess 52 and the component is preferably 1.0 times or more, more preferably 2.0 times or more, and further preferably 3.0 times or more.

  In the first embodiment, the case where both the relay electrode 46 and the sealing metal layer 50 are formed on the bottom surface of the recess 52 is shown as an example. However, at least one of the relay electrode 46 and the sealing metal layer 50 is a recess. It may be formed on the bottom surface of 52.

  In addition, in Example 1, although the case where both the electrode 20 for elements and the sealing metal layer 22 were provided in the board | substrate 10 was shown as an example, at least one of the electrode 20 for elements and the sealing metal layer 22 was provided. It may be the case. Similarly, the case where both the relay electrode 46 and the sealing metal layer 50 are provided on the substrate 30 has been described as an example. However, at least one of the relay electrode 46 and the sealing metal layer 50 may be provided. .

  In the first embodiment, the case where the substrate 10 is a piezoelectric substrate and the elastic wave element 16 including the IDT 12 that excites an elastic wave is formed on the main surface of the substrate 10 is described as an example, but the present invention is not limited thereto. The substrate 10 may be a silicon substrate, a quartz substrate, a glass substrate, a ceramic substrate, a gallium arsenide (GaAs) substrate, or the like, and a piezoelectric thin film resonator that excites an elastic wave may be formed on the main surface of the substrate 10.

  In the first embodiment, the case where the substrate 30 is a silicon substrate and the piezoelectric thin film resonator 32 that excites an elastic wave is formed on the main surface of the substrate 30 is described as an example, but the present invention is not limited thereto. The substrate 30 may be a quartz substrate, a glass substrate, a ceramic substrate, or a gallium arsenide substrate, and the piezoelectric thin film resonator 32 may be formed on the main surface of the substrate 30. Alternatively, the substrate 30 may be a piezoelectric substrate, and an elastic wave element including an IDT that excites an elastic wave may be formed on the main surface of the substrate 30.

  In the first embodiment, the piezoelectric thin film resonator 32 may not be formed on the main surface of the substrate 30 and only a wiring that is not electrically connected to the relay electrode 46 may be formed. In addition, passive components such as an inductor, a capacitor, and a resistor may be provided. Even if no wiring is formed on the main surface of the substrate 30, if the solder 60, 62 is formed so as to protrude beyond a predetermined region, the characteristics of the acoustic wave element 16 may change. There may be a case where no wiring is formed on the main surface of 30.

  In the first embodiment, as shown in FIG. 3, the case where the side surface of the recess 52 formed in the substrate 30 is a vertical plane is shown as an example, but the present invention is not limited thereto. FIG. 7A and FIG. 7B are cross-sectional views of modified examples of the recess 52. As shown in FIG. 7A, the side surface of the recess 52 may be an inclined surface. As shown in FIG. 7B, the side surface of the recess 52 may be a stepped surface. Further, a combination of a vertical plane, an inclined plane, and a stepped plane may be used.

  FIG. 8 is a cross-sectional view of the acoustic wave device 200 according to the second embodiment. As shown in FIG. 8, in the acoustic wave device 200 according to the second embodiment, a convex portion 54 is formed on the main surface of the substrate 30 instead of the concave portion 52. The height H1 of the convex portion 54 is, for example, about 3 μm to 7 μm. The height of each of the plurality of convex portions 54 is approximately the same. The piezoelectric thin film resonator 32 is provided in a region other than the convex portion 54 on the main surface of the substrate 30. The relay electrode 46, the element electrode 48, and the sealing metal layer 50 are provided on the upper surface of the convex portion 54 of the substrate 30. An interval H2 between the substrate 10 and the convex portion 54 of the substrate 30 is, for example, about 2 μm or less. The height H1 of the convex portion 54 is larger than the distance H2 between the substrate 10 and the convex portion 54 of the substrate 30. Since other configurations are the same as those of the first embodiment, the description thereof is omitted.

  According to the second embodiment, the relay electrode 46 to which the element electrode 20 of the substrate 10 is joined by the solder 60 is provided on the upper surface of the convex portion 54 formed on the substrate 30. Thereby, the distance between the relay electrode 46 and the piezoelectric thin film resonator 32, the wiring 44, and the sealing metal layer 50 can be lengthened. Similarly, the sealing metal layer 50 to which the sealing metal layer 22 of the substrate 10 is joined by the solder 62 is provided on the upper surface of the convex portion 54 formed on the substrate 30. Accordingly, the distance between the sealing metal layer 50 and the piezoelectric thin film resonator 32, the relay electrode 46, the element electrode 48, and the wiring 44 can be increased. Therefore, it is possible to suppress the solders 60 and 62 from coming into contact with the piezoelectric thin film resonator 32, the wiring 44, etc., and to improve the reliability.

  Further, as in Example 2, the relay electrode 46 and the sealing metal layer 50 are provided on the upper surface of the convex portion 54 of the substrate 30, so that even when the element electrode 20 and the sealing metal layer 22 are low, The height of the gap 64 can be ensured. Thus, in Example 2, since the electrode 20 for elements and the sealing metal layer 22 can be made low, manufacture becomes easy. In addition, since the convex portion 54 is formed by etching or the like, the height can be controlled with high accuracy, so that the height of the gap 64 can also be controlled with high accuracy.

  In the second embodiment, the height of the convex portion 54 on which the relay electrode 46 is formed is high from the viewpoint of suppressing the inflow of the solder 60 into the component (for example, the piezoelectric thin film resonator 32) formed on the main surface of the substrate 30. The length is preferably 1.0 times or more of the minimum distance between the convex portion 54 and the component, more preferably 2.0 times or more, and further preferably 3.0 times or more. Similarly, from the viewpoint of suppressing the inflow of the solder 62 to the component (for example, the piezoelectric thin film resonator 32) formed on the main surface of the substrate 30, the height of the convex portion 54 on which the sealing metal layer 50 is formed is The minimum distance between the convex portion 54 and the component is preferably 1.0 times or more, more preferably 2.0 times or more, and even more preferably 3.0 times or more.

  In the second embodiment, the case where both the relay electrode 46 and the sealing metal layer 50 are formed on the upper surface of the convex portion 54 is shown as an example. However, at least one of the relay electrode 46 and the sealing metal layer 50 is The case where it forms in the upper surface of the convex part 54 may be sufficient.

  In the second embodiment, as shown in FIG. 8, the case where the side surface of the convex portion 54 formed on the substrate 30 is a vertical plane is shown as an example, but the present invention is not limited to this. FIG. 9A to FIG. 9E are cross-sectional views of modified examples of the convex portion 54. As shown in FIG. 9A, the side surface of the convex portion 54 may be a tapered inclined surface, or as shown in FIG. 9B, it is an inversely tapered inclined surface. But you can. As shown in FIG. 9C, the side surface of the convex portion 54 may be a combination of a vertical plane and an inclined plane. As shown in FIG. 9D, the side surface of the convex portion 54 may be a combination of a vertical plane and a stepped surface. Moreover, the case where the side surface of the convex part 54 is only a stepped surface may be sufficient, and the case where it is a combination of an inclined surface and a stepped surface may be sufficient. As shown in FIG. 9E, the height of the side surface of the convex portion 54 may be partially different.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

10, 30 Substrate 12 IDT
16 acoustic wave element 18 wiring 20 element electrode 22 sealing metal layer 32 piezoelectric thin film resonator 34 lower electrode 36 piezoelectric thin film 38 upper electrode 40 resonance region 44 wiring 46 relay electrode 48 element electrode 50 sealing metal layer 52 recess 54 convex Part 56 Internal wiring 60, 62 Solder 64 Void 66 Metal film 100, 200 Elastic wave device

Claims (8)

The main surface has at least one of the first electrode and the first sealing metal layer, and at least one of the first electrode and the first sealing metal layer is formed on the bottom surface or the convex portion of the concave portion formed on the main surface. A first substrate provided on an upper surface;
The main surface has a first functional part for exciting elastic waves, and at least one of a second electrode and a second sealing metal layer electrically connected to the first functional part, and the second electrode is made of solder The first electrode is bonded to the first electrode and / or the second sealing metal layer is bonded to the first sealing metal layer by solder so as to seal the first functional part. An acoustic wave device comprising: a second substrate mounted on the first substrate with a gap exposing the first functional unit between the substrate and the substrate. The first substrate has both the first electrode and the first sealing metal layer,
The second substrate has both the second electrode and the second sealing metal layer,
2. The acoustic wave device according to claim 1, wherein the second electrode is joined to the first electrode by solder and the second sealing metal layer is joined to the first sealing metal layer by solder. .   The acoustic wave device according to claim 2, wherein both the first electrode and the first sealing metal layer are provided on a bottom surface of the concave portion or an upper surface of the convex portion.   A metal film having a melting point higher than that of solder is provided so as to surround the stacked body of the first sealing metal layer and the second sealing metal layer so as to cover an exposed surface of the stacked body. The acoustic wave device according to claim 2 or 3. The second substrate is a piezoelectric substrate;
The elastic wave device according to any one of claims 1 to 4, wherein the first functional unit is an IDT.   6. The device according to claim 1, further comprising: a second functional unit that is provided on the main surface other than the concave portion or the convex portion of the first substrate and is exposed to the gap and that excites an elastic wave. The acoustic wave device according to one item.   7. The acoustic wave device according to claim 6, wherein the second functional unit is a region where the upper electrode, the piezoelectric thin film, and the lower electrode of the piezoelectric thin film resonator overlap. The acoustic wave device according to any one of claims 1 to 7, wherein the first substrate is a silicon substrate.

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