JP2014014131A - Acoustic wave device built-in module and communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acoustic wave device built-in module which inhibits moisture etc. from intruding into a cavity on an electrode exciting an acoustic wave, and to provide a communication device.SOLUTION: An acoustic wave device built-in module includes: a multilayer wiring board 12 where an insulation layer 14 and a wiring layer 16 are laminated; multiple acoustic wave devices 20 which are incorporated into the multilayer wiring board 12; and an antenna switch 40 provided on the multilayer wiring board 12 and electrically connected with the acoustic wave device 20. Each acoustic wave device 20 includes: an IDT0 that is an electrode provided on a piezoelectric substrate 22 and exciting an acoustic wave; and a sealing part 28 including a frame 24, which is provided on the piezoelectric substrate 22 enclosing the IDT0, and a lid 26 which is provided on the frame 24 so as to have a cavity 30 on the IDT0. The lid 26 is recessed toward the piezoelectric substrate 22 side.

Description

  The present invention relates to an elastic wave device built-in module and a communication apparatus in which an elastic wave device is built in a multilayer wiring board.

  2. Description of the Related Art Elastic wave devices that use elastic waves are used in filters and duplexers of wireless communication devices such as mobile phone terminals, for example. There are surface acoustic wave devices that use surface acoustic waves and bulk wave devices that use bulk waves. In the surface acoustic wave device, a comb-like IDT (Interdigital Transducer) electrode is provided on a piezoelectric substrate. A Love wave device or a boundary acoustic wave device in which a dielectric film is provided so as to cover the IDT electrode is also included in the surface acoustic wave device. On the other hand, as a bulk wave device, there is a piezoelectric thin film resonator device in which upper and lower surfaces of a piezoelectric film are sandwiched between electrodes. A Lamb wave device using Lamb waves is also included in the bulk wave device.

  In an acoustic wave device, in order to maintain the characteristics, electrodes for exciting an acoustic wave (an IDT electrode formed on a piezoelectric substrate or a pair of electrodes arranged on the upper and lower surfaces of a piezoelectric film so as to overlap in the thickness direction) A sealing part having a gap (space) is provided on the top.

  In addition, miniaturization of wireless communication devices has been promoted, and accordingly, a module on which an acoustic wave device is mounted is required to be further miniaturized. In order to reduce the size and thickness of such a module, it is known that an acoustic wave device is arranged in a multilayer wiring board in which a wiring layer made of metal or the like and an insulating layer made of resin or the like are laminated (for example, Patent Documents). 1). On the other hand, it is known that when the resin is heated, moisture or unreacted products in the resin are vaporized and degassed (for example, Patent Document 2).

JP 2006-351590 A JP 2007-258776 A

  In an elastic wave device built-in module in which an elastic wave device is built in a multilayer wiring board in which a wiring layer and an insulating layer are laminated, even when the electrode for exciting the elastic wave is sealed by the sealing portion, Moisture or the like may enter the gap (space). Thereby, corrosion of the electrode which excites an elastic wave arises, and the characteristic as an elastic wave device will deteriorate. In addition, when mounting a module with a built-in elastic wave device on a motherboard or the like of an electronic device, moisture or the like that has entered the gap on the electrode that excites the elastic wave is vaporized and expanded by heating during mounting, and the elastic wave device May cause stress and cracks.

  The present invention has been made in view of the above-described problems, and provides an elastic wave device built-in module and a communication apparatus that can prevent moisture and the like from entering a gap (space) on an electrode that excites an elastic wave. For the purpose.

  The present invention provides a multilayer wiring board in which an insulating layer and a wiring layer are laminated, a plurality of acoustic wave devices incorporated in the multilayer wiring board, and provided in the multilayer wiring board, and electrically connected to the acoustic wave device. And an antenna switch connected thereto, wherein the acoustic wave device includes an electrode that excites an acoustic wave provided on a substrate, a frame that surrounds the electrode and that is provided on the substrate, and a gap above the electrode. And a sealing portion including a lid provided on the frame body, and the lid is recessed on the substrate side. According to the present invention, since the pressure in the gap can be increased, it is possible to prevent moisture and the like from entering the gap.

  In the above configuration, the pressure in the gap may be higher than the pressure in the gap on the electrode when the lid is flat without being recessed toward the substrate.

  The said structure WHEREIN: The said insulating layer can be set as the structure currently formed with resin.

  The said structure WHEREIN: The said lid can be set as the structure currently formed with the metal.

  The said structure WHEREIN: The dent amount of the said lid can be set as the structure smaller than half of the thickness of the said lid.

  In the above configuration, the recess amount of the lid may be a recess amount in which an interval between the electrode for exciting an elastic wave provided on the substrate and the lid is separated by 10 μm or more.

  The said structure WHEREIN: It can be set as the structure by which the insulator of the material different from the said insulating layer is interposed between the said lid and the said insulating layer.

  The said structure WHEREIN: The said acoustic wave device can be set as the structure incorporated in the center part of the thickness direction of the said multilayer wiring board.

  The said structure WHEREIN: The said acoustic wave device can be set as the structure containing a surface acoustic wave device.

  The said structure WHEREIN: The said elastic wave device can be set as the structure containing a bulk wave device.

  In the above configuration, a duplexer may be formed by the acoustic wave device.

  The present invention is a communication device having the elastic wave built-in module described above.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that a water | moisture content etc. penetrate | invade into the space | gap on the electrode which excites an elastic wave.

FIG. 1 is a cross-sectional view illustrating an elastic wave device built-in module according to Comparative Example 1. FIG. 2 is a cross-sectional view illustrating the elastic wave device built-in module according to the first embodiment. 3A is an external perspective view showing one acoustic wave device in a state of being incorporated in the elastic wave device built-in module shown in FIG. 2, and FIG. 3B is shown in FIG. It is a top view which shows the structure of the elastic wave device at the time of seeing through a lid. FIG. 4 is a cross-sectional view taken along line AA in FIG. 5A and 5B are cross-sectional views (part 1) illustrating the method for manufacturing the elastic wave device built-in module according to the first embodiment. FIG. 6A is a plan view illustrating a method for manufacturing the elastic wave device built-in module according to the first embodiment, and FIG. 6B is a cross-sectional view illustrating the method for manufacturing the elastic wave device built-in module according to the first embodiment. Part 2). FIG. 7 is a cross-sectional view (part 3) illustrating the method for manufacturing the elastic wave device built-in module according to the first embodiment. FIG. 8A to FIG. 8C are cross-sectional views (part 3) illustrating the method for manufacturing the elastic wave device built-in module according to the first embodiment. FIGS. 9A and 9B are cross-sectional views (part 4) illustrating the method for manufacturing the elastic wave device built-in module according to the first embodiment. FIG. 10A and FIG. 10B are cross-sectional views (part 5) illustrating the method for manufacturing the elastic wave device built-in module according to the first embodiment. FIG. 11 is a cross-sectional view showing a surface acoustic wave device in which a frame and a lid are formed of an insulator. FIG. 12A is a plan view showing a piezoelectric thin film resonator device, and FIG. 12B is a cross-sectional view taken along line AA in FIG. FIG. 13 is a block diagram illustrating the duplexer. FIG. 14 is a cross-sectional view illustrating the module with a built-in acoustic wave device according to the first modification of the first embodiment. FIG. 15 is a block diagram illustrating the communication apparatus according to the second embodiment.

  FIG. 1 is a cross-sectional view illustrating an elastic wave device built-in module according to Comparative Example 1. As shown in FIG. 1, the elastic wave device built-in module according to Comparative Example 1 includes an elastic wave device 110 built in a multilayer wiring board 106 in which a plurality of insulating layers 102 and wiring layers 104 are laminated. The plurality of wiring layers 104 stacked via the insulating layer 102 are electrically connected to each other by through wiring (interlayer connection wiring) 108 extending in the thickness direction of the insulating layer 102. On the surface of the multilayer wiring board 106, electronic components 130 such as inductors, capacitors, and high frequency ICs (Integrated Circuits) are mounted.

  The acoustic wave device 110 is a surface acoustic wave device including a comb-like IDT (Interdigital Transducer) electrode IDT0 formed on a piezoelectric substrate 112 and reflectors R0 disposed on both sides thereof. On the piezoelectric substrate 112, a metal sealing portion 114 that seals the IDT0 and the reflector R0 is provided. Sealing portion 114 includes a frame 116 that surrounds IDT0 and reflector R0, and a lid 118 that is provided on frame 116 so that gap 120 is formed on IDT0. On the piezoelectric substrate 112 around the sealing portion 114, a protruding electrode 122 for electrically connecting the IDT0 to the outside is provided. The protruding electrode 122 can be electrically connected to the electronic component 130 or the like via the wiring layer 104 and / or the through wiring (interlayer connection wiring) 108.

  As shown in FIG. 1, when the acoustic wave device 110 is disposed in the multilayer wiring board 106, moisture enters the gap (space) 120 on the IDT 0 and the IDT 0 is corroded, and the acoustic wave device 110 The characteristic is likely to deteriorate. Such moisture penetrates in the manufacturing process of the elastic wave device built-in module, or penetrates due to a change with time after the formation of the elastic wave device built-in module. Further, the moisture enters the gap 120 from some interface such as the interface between the piezoelectric substrate 112 and the frame body 116 or the interface between the frame body 116 and the lid 118. For example, when an insulating layer is interposed between the wiring and the frame 116 so as to electrically insulate the wiring 116 and the wiring connecting the IDT0 and the protruding electrode 122, Moisture enters from the interface between the insulator layer and the frame body 116. In particular, when the insulating layer 102 is formed of an epoxy resin, a polyimide resin, a thermoplastic liquid crystal polymer sheet, or the like, the resin has a hygroscopic property, so that moisture easily enters the gap 120.

  Further, the sealing portion 114 is formed by joining the frame body 116 and the lid 118 with, for example, solder. This joining process is performed in a high temperature environment equal to or higher than the melting point of the solder. For this reason, if the volume of the space | gap 120 is constant when returning from this high temperature state to normal temperature, the pressure in the space | gap 120 will fall. Thus, if the inside of the space | gap 120 will be in a pressure reduction state, it will be encouraged that a water | moisture content penetrate | invades into this space | gap 120. FIG. Furthermore, when the insulating layer 102 is formed of resin, moisture and / or unreacted products (for example, from the insulating layer 102 due to heat when the module with built-in elastic wave device is mounted on a motherboard or the like of an electronic device) Fluorine or chlorine) is vaporized and degassed. At this time, moisture and / or unreacted products generated in the insulating layer 102 which is the inner layer of the multilayer wiring board 106 are retained in the multilayer wiring board 106 without being released to the outside. For this reason, these moisture and / or unreacted products may also enter the gap 120 due to changes over time.

  As described above, in an elastic wave device built-in module in which an elastic wave device is built in a multilayer wiring board, moisture or the like enters the gap on the electrode that excites the elastic wave in the elastic wave device. As a result, the characteristics of the acoustic wave device are deteriorated. Therefore, in order to solve such a problem, an embodiment capable of suppressing the entry of moisture or the like into the gap provided on the electrode for exciting the elastic wave will be described below.

  FIG. 2 is a cross-sectional view illustrating the elastic wave device built-in module according to the first embodiment. As shown in FIG. 2, in the elastic wave device built-in module 10 according to the first embodiment, the elastic wave device 20 is embedded and arranged in the multilayer wiring board 12. The acoustic wave device 20 is housed and disposed at a substantially central portion in the thickness direction of the multilayer wiring board 12. The multilayer wiring board 12 is a laminated substrate in which a plurality of insulating layers 14 and wiring layers 16 are laminated. The plurality of stacked wiring layers 16 are electrically connected to each other by through wiring (also referred to as interlayer connection wiring) 18 that penetrates the insulating layer 14. The wiring layer 16 and the through wiring 18 are made of a metal such as copper (Cu), for example. On the other hand, the insulating layer 14 is formed of, for example, an epoxy resin, a polyimide resin, or a thermoplastic liquid crystal polymer sheet.

Here, the acoustic wave device 20 housed and incorporated in the acoustic wave device built-in module 10 will be described. 3A is an external perspective view showing one acoustic wave device 20 in a state of being incorporated in the elastic wave device built-in module shown in FIG. 2, and FIG. 3B is a perspective view of FIG. It is a top view which shows the structure of the elastic wave device 20 at the time of seeing through the shown lid 26. FIG. Here, the display of the insulating layer 14 and the wiring layer 16 around the acoustic wave device 20 is omitted. 3A and 3B, the acoustic wave device 20 includes a substrate 22 (hereinafter referred to as a piezoelectric substrate) made of a piezoelectric material such as lithium tantalate (LiTaO ₃ ) or lithium niobate (LiNbO ₃ ). The surface acoustic wave device comprises IDT0 and reflectors R0 disposed on both sides thereof. The thickness of the piezoelectric substrate 22 is, for example, 250 μm. The IDT0 and the reflector R0 are made of a metal such as aluminum (Al), for example. In FIG. 3B, only one IDT0 and reflectors R0 disposed on both sides thereof are displayed. However, in one acoustic wave device, such IDT0 and reflector R0 are displayed. A desired circuit such as a filter circuit is formed by combining a plurality of acoustic wave device elements including

  On the piezoelectric substrate 22, a frame 24 having a substantially rectangular planar shape is disposed so as to surround the IDT0 and the reflector R0. The frame body 24 is formed of a metal including, for example, Cu or nickel (Ni), and the thickness thereof is, for example, 30 μm. On the frame 24, a plate-shaped lid 26 is disposed so as to cover the IDT0 and the reflector R0 so that a gap 30 is formed on the IDT0 and the reflector R0. The lid 26 is formed of a metal plate containing, for example, Cu or Ni, and has a thickness of 20 μm, for example. As a result, the IDT 0 and the reflector R 0 are sealed in a gap 30 formed by a sealing portion 28 including the frame body 24 and the lid 26.

  Four protruding electrodes 32 are arranged on the upper surface of the piezoelectric substrate 22 outside the sealing portion 28. Of the four protruding electrodes 32, one protruding electrode 32A is for signal input, and the other protruding electrode 32B is for signal output. Further, the remaining two protruding electrodes 32C and 32D are for grounding. The signal input protruding electrode 32A and the signal output protruding electrode 32B are electrically connected to the IDT0 via the wiring 34. In addition, an insulating layer (not shown) is disposed between the wire 34 connected to the signal input protrusion electrode 32A and the signal output protrusion electrode 32B and the frame body 24, and the wiring 34 and the frame body 24 are connected to each other. They are electrically insulated. On the other hand, the ground (grounding) protruding electrodes 32 </ b> C and 32 </ b> D are electrically connected to the frame body 24 via the wiring 35. In other words, in the acoustic wave device 20, the IDT 0 and the reflector R 0 are shielded against an external electromagnetic field by the frame body 24 and the lid 26.

  FIG. 4 is a cross-sectional view taken along line AA in FIG. As shown in FIG. 4, each protruding electrode 32 is made of, for example, gold (Au) -tin (Sn) solder disposed between a columnar lower portion 32a, a columnar upper portion 32b, and both columnar portions. A joining member 36 is used. On the other hand, the frame 24 and the lid 26 constituting the sealing portion 28 are also joined by a joining member 36 made of gold (Au) -tin (Sn) solder. In the elastic wave device 20 arranged in the elastic wave device built-in module 10 according to the first embodiment, the upper surface of the lid 26 is not a flat surface, but moves toward the piezoelectric substrate 22 as the distance from the frame body 24 increases. A curved deformation (a shape recessed in a direction approaching the surface of the piezoelectric substrate 22) occurs. That is, as the lid 26 is deformed to the surface side of the piezoelectric substrate 22, the volume of the gap (space) 30 existing on the IDT0 and the reflector R0 is reduced. The bending amount X of the lid 26 is smaller than half of its thickness, and the minimum distance between the lid 26 and the IDT0 is ensured to be 10 μm or more. Further, in the perspective view of FIG. 3A, the state of bending is omitted.

  In FIG. 2, the protruding electrode 32 included in the acoustic wave device 20 incorporated in the multilayer wiring board 12 is connected to the wiring layer 16 and the through wiring 18. At least a part of the wiring layer 16 </ b> A formed on the upper surface of the multilayer wiring board 12 is used as a terminal pad, and an electronic component 40 is mounted on the terminal pad by solder 42. The electronic component 40 is a chip component such as a resistance element, an inductor, or a capacitor, a power amplifier, an antenna switch, an active element of a high frequency IC, or the like, and is mounted on a terminal pad as necessary. With such a configuration, the acoustic wave device 20 and the electronic component 40 are electrically connected. The acoustic wave device 20 and the electronic component 40 are also electrically connected to the wiring layer 16B formed on the lower surface of the multilayer wiring board 12 as necessary. The wiring layer 16B on the lower surface of the multilayer wiring board 12 functions as an external terminal pad for external connection of the elastic wave device built-in module 10. That is, the acoustic wave device 20 and the electronic component 40 are electrically connected to terminals and the like on the motherboard of the electronic device via the wiring layer 16B on the lower surface of the multilayer wiring board 12.

  Next, a manufacturing method of the elastic wave device built-in module according to the first embodiment will be described. FIGS. 5A and 5B and FIGS. 6B to 10B are cross-sectional views illustrating a method for manufacturing the module with a built-in acoustic wave device according to the first embodiment. FIG. 6A is a plan view illustrating the method for manufacturing the elastic wave device built-in module according to the first embodiment. First, with reference to FIGS. 5A and 5B, a method for manufacturing an acoustic wave device built in the module incorporating an acoustic wave device according to the first embodiment will be described. As shown in FIG. 5A, the IDT0, the reflector R0, the frame 24 that surrounds the IDT0 and the reflector R0, and the protruding electrodes that are located outside the frame 24 are formed on the piezoelectric substrate 22 by using known means. A lower portion 32a of 32 is formed. The IDT0 and the reflector R0 can be formed using, for example, a metal vapor deposition and lift-off method mainly composed of aluminum. The frame 24 and the lower portion 32a of the protruding electrode 32 can be formed by, for example, applying an electroplating method and selectively depositing a metal mainly composed of copper.

  In parallel with the formation of the metal layer on the piezoelectric substrate 22, the lid 26 and the upper portion 32 b of the protruding electrode 32 are formed on a support substrate 44 made of stainless steel such as SUS304 (downward in FIG. 5). Are selectively formed. Thereafter, a bonding member 36 made of, for example, gold (Au) -tin (Sn) solder is formed on the edge of the upper surface of the lid 26 and the upper surface of the upper portion 32 b of the protruding electrode 32. The lid 26, the upper portion 32b of the protruding electrode 32, and the bonding member 36 can be formed using, for example, an electrolytic plating method.

  Then, the support substrate 44 is disposed on the piezoelectric substrate 22 so that the lid 26 faces the frame body 24 and the upper portion 32b of the protruding electrode 32 faces the lower portion 32a. Then, the bonding member 36 is heated to a temperature equal to or higher than the melting point of the bonding member 36 (for example, 250 ° C. to 300 ° C.), and the support substrate 44 is pressed toward the piezoelectric substrate 22 side.

  Thereby, the lid 26 is joined on the frame body 24 via the joining member 36, and the sealing portion 28 having the gap 30 is formed on the IDT0 and the reflector R0 as shown in FIG. 5B. Further, the lower portion 32 a and the upper portion 32 b of the protruding electrode 32 are bonded by the bonding member 36, and the protruding electrode 32 is formed. Thereafter, by removing the support substrate 44, the sealing portion 28 having the gap 30 is formed on the IDT0 and the reflector R0, and a plurality of protruding electrodes 32 are disposed around the sealing portion 28. The acoustic wave device 20 is formed. At this stage, the surface of the lid 26 has a flat shape. On the other hand, since the frame member 24 and the lid 26 are joined by melting the joining member 36 in a high temperature environment, the pressure in the gap 30 decreases when returning from high temperature to room temperature, The pressure is lower than the external pressure.

  The lid 26 preferably contains Cu in order to obtain high heat dissipation and low electrical resistance, and it is preferable to provide a Ni layer on the Cu layer in order to reduce thickness non-uniformity. The support substrate 44 is preferably made of a material that functions as a base material for plating with respect to Cu, such as SUS304, and has such adhesiveness that it can be easily peeled off from the lid 26 after sealing. Further, the same piezoelectric material as that of the piezoelectric substrate 22 may be used as the support substrate 44 in order to reduce the positional deviation due to the difference in thermal expansion coefficient. When a piezoelectric body is used as the support substrate 44, a metal layer for electrolytic plating (for example, an Al layer or a Cu layer) is provided on the surface of the support substrate 44, and a metal layer (for example, an appropriate adhesiveness with the plating layer is further formed thereon. , Ti layer) is preferably formed.

  As shown in FIGS. 6A and 6B, the acoustic wave device 20 formed by the manufacturing process as described above has through-wirings 18 penetrating the upper and lower surfaces, and further has wiring layers 16a on both sides. It is embedded in the selectively formed insulating layer 14a. At this time, it is preferable that the upper surface of the acoustic wave device 20 is exposed on the upper surface of the insulating layer 14a, and at least the upper surface of the lid 26 is flush with the upper surface of the insulating layer 14a.

  Thereafter, as shown in FIG. 7, the prepreg insulating layer 14b and the wiring layer 16b are sequentially arranged on the upper surface side of the insulating layer 14a, while the prepreg insulating layer 14c and the wiring layer 16c are arranged on the lower surface side of the insulating layer 14a. Are arranged in order. Thereafter, the insulating layers 14b and 14c and the wiring layers 16b and 16c are heated, and the insulating layers 14b and 14c and the wiring layers 16b and 16c are pressed toward the insulating layer 14a using the support 46. As a result, as shown in FIG. 8A, the insulating layers 14b and 14c and the wiring layers 16b and 16c are pressure-bonded to the insulating layer 14a to obtain a laminated substrate in which the acoustic wave device 20 is built. At this time, since the pressure applied to the insulating layers 14b and 14c and the wiring layers 16b and 16c is also applied to the acoustic wave device 20, the lid 26 can be made piezoelectric by appropriately selecting the material and thickness of the lid 26. A deformation (a shape recessed in a direction approaching the surface of the piezoelectric substrate 22) is generated on the substrate 22 side. Since the lid 26 has a shape that is recessed in a direction approaching the surface of the piezoelectric substrate 22, the volume of the gap 30 is reduced, and the gap 30 is smaller than when the lid 26 before being embedded in the insulating layer 14 a has a flat shape. The pressure inside increases. In addition, since the amount of recesses of the lid 26 depends on the material and thickness thereof, the material and thickness of the lid 26 are selected in advance so that the desired amount of recesses is obtained.

  As shown in FIG. 8B, by using a resist layer (not shown) provided on the upper surface of the wiring layer 16b and the lower surface of the wiring layer 16c as a mask, the wiring layers 16b and 16c are subjected to, for example, an etching process. Then, openings are formed in the wiring layers 16b and 16c. In this opening, the insulating layers 14b and 14c are exposed. By irradiating the insulating layers 14b and 14c exposed at the openings with, for example, a laser, the through holes 48 penetrating the insulating layers 14b and 14c are formed. In the through hole 48, the wiring layer 16a is exposed.

  As shown in FIG. 8C, the through wiring 18 is formed in the through hole 48. The through wiring 18 can be formed by first forming a seed metal by an electroless plating method and using the seed metal as a power supply line by an electrolytic plating method. Since the plating layer is also formed on the upper surface of the insulating layer 14b and the lower surface of the insulating layer 14c, the wiring layers 16b and 16c are formed again on the entire upper surface of the insulating layer 14b and the entire lower surface of the insulating layer 14c.

  As shown in FIG. 9A, a resist layer (not shown) provided on the upper surface of the wiring layer 16b and the lower surface of the wiring layer 16c is used as a mask, and the wiring layers 16b and 16c are subjected to, for example, an etching process. The wiring layers 16b and 16c are patterned into a desired shape.

  As shown in FIGS. 9B and 10A, the same processing as that described in FIGS. 7 to 9A is repeated to form the multilayer wiring board 12 in which the acoustic wave device 20 is built. . Thereafter, as shown in FIG. 10B, the solder 42 is supplied to the wiring layer 16 on the upper surface of the multilayer wiring board 12 and reflowed to mount the electronic component 40 electrically connected to the acoustic wave device 20. . Thereby, the elastic wave device built-in module 10 according to the first embodiment is formed.

  According to the first embodiment, as shown in FIGS. 2 and 4, the lid 26 constituting the sealing portion 28 of the acoustic wave device 20 built in the multilayer wiring board 12 has a concave shape on the piezoelectric substrate 22 side. The volume of the gap 30 formed by the sealing portion 28 is reduced. Thereby, the pressure in the space | gap 30 increases and it can suppress that a water | moisture content etc. penetrate | invade into the space | gap 30. FIG. As a result, deterioration of the characteristics of the acoustic wave device 20 can be suppressed.

  From the viewpoint of preventing moisture and the like from entering the gap 30, the pressure in the gap 30 is preferably higher than the pressure in the gap 30 when the lid 26 is flat. For example, if the amount of curvature X (the amount of depression X) of the lid 26 is 1% or more of the height of the gap 30 when the lid 26 is flat, the pressure in the gap 30 is increased and moisture or the like enters. Can be suppressed. Further, in order to further increase the pressure in the gap 30 and more effectively suppress the intrusion of moisture or the like, the recess amount X of the lid 26 is equal to the height of the gap 30 when the lid 26 is flat. It is preferably 5% or more. It is more preferably 10% or more, and further preferably 20% or more.

  In the first embodiment, the case where both the frame body 24 and the lid 26 are made of metal is shown as an example, but the present invention is not limited to this. The frame body 24 and the lid 26 may be formed of a resin such as polyimide or an epoxy resin, or an insulator such as a ceramic material. FIG. 11 is a cross-sectional view showing a surface acoustic wave device in which a frame and a lid are formed of an insulator. As shown in FIG. 11, a frame 24a made of resin, for example, is provided so as to surround the IDT0 and the reflector R0 provided on the piezoelectric substrate 22. On the frame 24a, a lid 26a made of, for example, a resin is provided so that a gap 30 is formed on the IDT0 and the reflector R0. Thereby, IDT0 and reflector R0 are sealed by the sealing part 28a which has the frame 24a and the lid 26a. A through electrode 49 penetrating the sealing portion 28a and electrically connected to the IDT0 is provided. Note that no joining member is interposed between the frame body 24a and the lid 26a, and the frame body 24a and the lid 26a are directly joined.

  Further, the frame body 24 and the lid 26 can be formed from different materials. For example, the frame body 24 may be formed of a metal, and the lid 26 may be formed of a ceramic material. The sealing portion 28 may include a member other than the frame body 24 and the lid 26. Furthermore, the sealing part 28 may be comprised with the cap-shaped member integrally formed.

  If the strength of the lid 26 is small, a large dent is formed in the lid 26 by the pressure applied when the insulating layer 14b, the insulating layer 14c, etc. shown in FIG. There is a possibility of coming into contact with IDT0. In addition, there is a possibility that a crack may occur in the lid 26. For this reason, the lid 26 preferably has a certain degree of strength, and is preferably formed of metal. Moreover, the heat dissipation and moisture resistance of the acoustic wave device 20 can be improved by forming the lid 26 with a metal. From the viewpoint of improving the heat dissipation and moisture resistance, it is desirable that the frame body 24 is also made of metal.

  When the lid 26 is formed of metal, as described with reference to FIGS. 5A and 5B, the lid 26 and the frame body 24 are bonded using the bonding member 36 made of solder, The sealing part 28 is formed. Since this joining process is performed in a high temperature environment, the inside of the space 30 is in a reduced pressure state after the sealing process. When the space 30 is in a reduced pressure state, moisture or the like easily enters the space 30. Therefore, when the lid 26 is made of metal, the lid 26 has a concave shape on the piezoelectric substrate 22 side, and the volume of the gap 30 formed by the sealing portion 28 is reduced in the sealing process. It is effective to compensate for the reduced pressure in the gap 30 and suppress the intrusion of moisture and the like.

  If the strength of the lid 26 is greater than necessary, the lid 26 hardly dents due to the pressure applied when the insulating layer 14b, the insulating layer 14c, etc. shown in FIG. . Therefore, it is preferable that the strength of the lid 26 is large enough to cause the lid 26 to be dented by the pressure applied when the insulating layer 14b, the insulating layer 14c, etc. are pressure-bonded to the insulating layer 14a. Since the strength and thickness of the lid 26 are correlated, when the lid 26 is formed of, for example, a metal such as Cu or Ni, an alloy containing such a metal as a component, or a ceramic material, the thickness of the lid 26 is 10 μm or more. The thickness is preferably set to 40 μm or less, and more preferably 20 μm to 30 μm.

  The insulating layer 14 constituting the multilayer wiring board 12 can be formed of an insulator other than resin. However, when the insulating layer 14 is formed of resin, the resin easily absorbs moisture as described above. , Moisture easily enters the gap 30. Therefore, when the insulating layer 14 is made of resin, it is preferable that the lid 26 has a concave shape on the piezoelectric substrate 22 side in order to increase the pressure in the gap 30 and suppress the entry of moisture and the like. .

  Further, the amount X of the recess in the lid 26 is set so that the lid 26 does not contact the IDT0. However, when the lid 26 is made of metal, the distance between the lid 26 and the IDT0 is 10 μm or more apart. Preferably it is. This is because when the distance between the lid 26 and IDT0 becomes small, the characteristics of the acoustic wave device 20 deteriorate due to the capacitance generated between the lid 26 and IDT0. For this reason, it is selected that the dent amount X of the lid 26 is, for example, less than ½ of the thickness of the lid 26. On the other hand, when the lid 26 is formed of an insulating material such as resin, the lid 26 is allowed to be recessed close to the IDT0 to a position that does not hinder the vibration of the IDT0.

  As shown in FIG. 2, the acoustic wave device 20 is preferably built in the central portion of the multilayer wiring board 12 in the thickness direction. Accordingly, the lid 26 constituting the sealing portion 28 of the acoustic wave device 20 can be easily formed into a shape recessed toward the piezoelectric substrate 22 by the pressure applied when the multilayer wiring board 12 is formed by pressure bonding. . That is, it is possible to easily increase the pressure in the gap 30.

  In the first embodiment, the case where the acoustic wave device 20 incorporated in the multilayer wiring board 12 is a surface acoustic wave device has been described as an example. However, as the acoustic wave device 20, a Love wave device or a boundary acoustic wave device is applied. Even in this case, the idea of the present invention can be applied. The acoustic wave device incorporated in the multilayer wiring board may be a bulk wave device such as a piezoelectric thin film resonator device or a Lamb wave device. Furthermore, one of the plurality of acoustic wave devices incorporated in the multilayer wiring board may be a surface acoustic wave device, and the other may be a bulk wave device. FIG. 12A is a plan view showing a piezoelectric thin film resonator device, and FIG. 12B is a cross-sectional view taken along line AA in FIG. As shown in FIGS. 12A and 12B, a lower electrode 52, a piezoelectric film 54 such as aluminum nitride, and an upper electrode 56 are sequentially stacked on a substrate 50 such as silicon. A region where the lower electrode 52 and the upper electrode 56 overlap with the piezoelectric film 54 interposed therebetween is a resonance region 58. A through hole 60 penetrating the substrate 50 is formed in the substrate 50 below the resonance region 58. In addition, instead of the through hole 60, a configuration in which a part of the substrate 50 is removed to form a void, a configuration in which a dome-shaped void is formed between the substrate 50 and the lower electrode 52, or an acoustic wave is reflected. It is also possible to apply a configuration in which an acoustic multilayer film is formed.

  Moreover, it is good also as a structure by which a splitter is formed with the elastic wave device incorporated in the multilayer wiring board. FIG. 13 is a block diagram illustrating the duplexer. As shown in FIG. 13, the duplexer 68 includes a transmission filter 62, a reception filter 64, and a matching circuit 66. The transmission filter 62 and the reception filter 64 are formed by an elastic wave device built in the multilayer wiring board. For example, in FIG. 2, one of the acoustic wave devices 20 incorporated in the multilayer wiring board 12 can be a transmission filter 62 and the other can be a reception filter 64. The electrodes for exciting the elastic waves of the respective filters may be formed on different piezoelectric substrates or may be formed on a common piezoelectric substrate. When formed on a common piezoelectric substrate, the electrodes for exciting a plurality of elastic waves may be sealed by one sealing portion.

  The transmission filter 62 is disposed and connected between the antenna terminal Ant and the transmission terminal Tx. The reception filter 64 is disposed and connected between the antenna terminal Ant and the reception terminal Rx. The matching circuit 66 is connected between at least one of the transmission filter 62 and the reception filter 64 and the antenna terminal Ant.

  The transmission filter 62 passes a signal in the transmission band among signals input from the transmission terminal Tx as a transmission signal to the antenna terminal Ant, and suppresses signals of other frequencies. The reception filter 64 passes a signal in the reception band among the signals input from the antenna terminal Ant to the reception terminal Rx as a reception signal, and suppresses signals of other frequencies. The matching circuit 66 is a circuit that matches the impedance so that the transmission signal that has passed through the transmission filter 62 does not leak to the reception filter 64 side and is output from the antenna terminal Ant.

  In Example 1, a metal layer such as Cu having a thickness similar to that of the insulating layer 14a may be disposed on the peripheral side surface of the insulating layer 14a shown in FIGS. 6 (a) and 6 (b). By arrange | positioning this metal layer, the intensity | strength and heat dissipation of the multilayer wiring board 12 can be improved.

  FIG. 14 is a cross-sectional view illustrating the module with a built-in acoustic wave device according to the first modification of the first embodiment. As shown in FIG. 14, in the elastic wave device built-in module 70 according to the first modification of the first embodiment, on the lid 26 constituting the sealing portion 28, for example, a resin such as polyimide resin or epoxy resin, or other An adjustment layer 72 made of an insulating material is provided. The adjustment layer 72 is formed of an insulating material different from that of the insulating layer 14. Other configurations are the same as those of the first embodiment shown in FIG.

  In the first modification of the first embodiment, an adjustment layer 72 made of an insulator is disposed between the lid 26 and the insulating layer 14. By adjusting the thickness of the adjustment layer 72, the amount of depression of the lid 26 can be adjusted by the pressure applied when the insulating layers 14b, 14c, etc. in FIG. 7 are pressed against the insulating layer 14a.

  For example, if the areas of the lids 26 of the plurality of acoustic wave devices 20 incorporated in the multilayer wiring board 12 are different, even if the same pressure is applied to each acoustic wave device 20, the lid 26 is provided for each acoustic wave device 20. The amount of dents in the case may be different. For example, in one of the plurality of acoustic wave devices 20, the lid 26 is hardly recessed, and in the other one, the lid 26 may be recessed so as to contact the IDT 0. However, as in the first modification of the first embodiment, the adjustment layer 72 is disposed on the lid 26 and the thickness of the adjustment layer 72 is selected for each elastic wave device 20, thereby providing a plurality of elastic wave devices. The amount of depression of the lid 26 in each of the 20 can be the same.

  The second embodiment is a communication apparatus having the elastic wave device built-in module according to the first embodiment. FIG. 15 is a block diagram illustrating the communication apparatus according to the second embodiment. As illustrated in FIG. 15, the communication device 80 according to the second embodiment includes an antenna 82, an antenna switch 84, a high-frequency IC 86, a power amplifier 88, a filter 90, a plurality of duplexers 92, a plurality of reception filters 94, and a plurality of low-pass filters. 96. The high frequency IC 86 has a plurality of low noise amplifiers 98. The high frequency IC 86 functions as a direct converter that converts the frequency of the signal.

  Each of the plurality of duplexers 92 corresponds to band 1, band 2, and band 5 in the W-CDMA (Wideband Code Division Multiple Access) system. Each of the plurality of reception filters 94 corresponds to the 850 MHz band, 900 MHz band, 1800 MHz band, and 1900 MHz band in the GSM (Global System for Mobile Communication) (registered trademark, hereinafter the same) method. One of the plurality of low-pass filters 96 has a function of a GSM low band (850 MHz band and 900 MHz band) transmission filter, and the other is a GSM high band (1800 MHz band and 1900 MHz band) transmission filter function. It has a function.

  The transmission filter 92 a included in each of the plurality of duplexers 92 is connected to the high frequency IC 86 via a power amplifier 88 and a filter 90. The filter 90 is a band-pass filter that selectively passes the same band as the pass band of the connected transmission filter 92a. The reception filter 92 b included in each of the plurality of duplexers 92 is connected to a low noise amplifier 98 in the high frequency IC 86. Each of the plurality of reception filters 94 is connected to a low noise amplifier 98 in the high frequency IC 86. The plurality of low-pass filters 96 are connected to the high frequency IC 86 via the power amplifier 88. The reception filter 92b and the reception filter 94 are not limited to balanced outputs, but may be unbalanced outputs.

  The antenna terminals (band 1, band 2, and band 5) of the plurality of duplexers 92 are connected to the antenna switch 84. The antenna terminals (GSM 850, GSM 900, GSM 1800, GSM 1900) of each of the plurality of reception filters 94 are connected to the antenna switch 84. The antenna terminals (GSM_LB Tx and GSM_HB Tx) of each of the plurality of low-pass filters 96 are connected to the antenna switch 84.

  The antenna switch 84 selects one of the duplexers and the filters according to the communication method and connects it to the antenna 82. For example, the high-frequency IC 86 up-converts the baseband signal into a W-CDMA band 5 RF signal to generate a transmission signal. The transmission signal is filtered by the filter 90, amplified by the power amplifier 88, and filtered again by the band 5 duplexer 92. The transmission signal is transmitted through the antenna 82. Also, the W-CDMA band 5 received signal received by the antenna 82 is filtered by the band 5 duplexer 92. The low noise amplifier 98 amplifies the received signal, and the high frequency IC 86 down-converts the received signal into a baseband signal.

  The elastic wave device built-in module 10 according to the first embodiment has a configuration having components (one duplexer 92 and one power amplifier 88) surrounded by a broken line in FIG. 15 and components surrounded by a one-dot chain line (antenna switch). 84, a plurality of duplexers 92, a plurality of reception filters 94, and a plurality of low-pass filters 96).

  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.

DESCRIPTION OF SYMBOLS 10, 70 Module with built-in elastic wave device 12 Multilayer wiring board 14 Insulating layer 16 Wiring layer 18 Through wiring 20 Elastic wave device 22 Piezoelectric substrate 24, 24a Frame body 26, 26a Lid 28, 28a Sealing part 30 Gap 32 Projection electrode 36 Joining Member 40 electronic component 68 duplexer 72 adjustment layer 80 communication device

Claims (12)

A multilayer wiring board in which an insulating layer and a wiring layer are laminated;
A plurality of acoustic wave devices incorporated in the multilayer wiring board;
An antenna switch provided on the multilayer wiring board and electrically connected to the acoustic wave device,
The elastic wave device is provided on the frame so as to have an electrode for exciting an elastic wave provided on the substrate, a frame provided on the substrate so as to surround the electrode, and a gap on the electrode. A sealing portion including a lid formed,
The module with a built-in acoustic wave device, wherein the lid is recessed toward the substrate.   The elastic wave device built-in module according to claim 1, wherein the pressure in the gap is higher than the pressure of the gap on the electrode when the lid is flat without being recessed toward the substrate.   The elastic wave device built-in module according to claim 1, wherein the insulating layer is made of a resin.   The elastic wave device built-in module according to claim 1, wherein the lid is made of metal.   The elastic wave device built-in module according to claim 4, wherein the amount of depression of the lid is smaller than half of the thickness of the lid.   5. The module with a built-in elastic wave device according to claim 4, wherein the concave amount of the lid is a concave amount in which an interval between an electrode for exciting an elastic wave provided on the substrate and the lid is separated by 10 μm or more. .   The elastic wave device built-in module according to claim 1, wherein an insulator made of a material different from the insulating layer is interposed between the lid and the insulating layer.   The elastic wave device built-in module according to claim 1, wherein the elastic wave device is built in a central portion in a thickness direction of the multilayer wiring board.   The module according to claim 1, wherein the acoustic wave device includes a surface acoustic wave device.   The elastic wave device built-in module according to claim 1, wherein the elastic wave device includes a bulk wave device.   11. The elastic wave device built-in module according to claim 1, wherein a branching filter is formed by the elastic wave device.   A communication apparatus comprising the elastic wave built-in module according to claim 1.

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