Patent Publication Number: US-2019181828-A1

Title: Electronic component module

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority to Japanese Patent Application No. 2017-237540 filed on Dec. 12, 2017 and Japanese Patent Application No. 2018-192317 filed on Oct. 11, 2018. The entire contents of these applications are hereby incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to electronic component modules, and more particularly, to an electronic component module including an elastic wave device and a mounting substrate on which the elastic wave device is mounted. 
     2. Description of the Related Art 
     An elastic wave device in which a lamination film including a piezoelectric thin film is laminated on a support substrate is known (see, for example, Japanese Unexamined Patent Application Publication No. 2017-011681). 
     The elastic wave device disclosed in Japanese Unexamined Patent Application Publication No. 2017-011681 includes a support substrate, a piezoelectric film, such as a piezoelectric thin film, an interdigital transducer (IDT) electrode, an insulation layer, a wiring electrode, a spacer layer such as a support layer, a cover, a penetration electrode, such as an under bump metal layer, and an external connection electrode, such as a metal bump. 
     Japanese Unexamined Patent Application Publication No. 2017-011681 describes that cracking, chipping, or the like is unlikely to occur in the piezoelectric film during a process of forming the external connection electrode. 
     In the elastic wave device disclosed in Japanese Unexamined Patent Application Publication No. 2017-011681, there is an advantage that cracking, chipping, or the like is unlikely to occur in the piezoelectric film during the process of forming the external connection electrode. However, in an electronic component module in which the above-discussed elastic wave device is mounted on a mounting substrate, since a coefficient of linear expansion of the support substrate and a coefficient of linear expansion of the mounting substrate often differ from each other, there is a problem that a crack is generated in the support substrate in some case. 
     SUMMARY OF THE INVENTION 
     Preferred embodiments of the present invention provide electronic component modules capable of reducing or preventing cracks, chips, or other damage in a piezoelectric film and reducing or preventing the occurrence of cracking in a support substrate. 
     An electronic component module according to a preferred embodiment of the present invention includes an elastic wave device and a mounting substrate. The elastic wave device is mounted on the mounting substrate. The elastic wave device includes a support substrate, a piezoelectric film, an interdigital transducer (IDT) electrode, an insulation layer, a wiring electrode, and an external connection electrode. The support substrate is a crystal substrate. The piezoelectric film is provided directly or indirectly on the support substrate. The IDT electrode is provided on the piezoelectric film. The insulation layer is provided on the support substrate. At least a portion of the wiring electrode is provided on the insulation layer. The wiring electrode is electrically connected to the IDT electrode. The external connection electrode is electrically connected to the wiring electrode. The external connection electrode and the piezoelectric film do not overlap each other in a plan view in a thickness direction of the support substrate. The elastic wave device is mounted on the mounting substrate via the external connection electrode. The mounting substrate has a coefficient of linear expansion different from a coefficient of linear expansion of the support substrate. A surface on the piezoelectric film side of the support substrate is a {100} plane. 
     An electronic component module according to a preferred embodiment of the present invention includes an elastic wave device and a mounting substrate. The elastic wave device is mounted on the mounting substrate. The mounting substrate is a printed wiring substrate or an LTCC substrate. The elastic wave device includes a support substrate, a piezoelectric film, an IDT electrode, an insulation layer, a wiring electrode, and an external connection electrode. The piezoelectric film is provided directly or indirectly on the support substrate. The IDT electrode is provided on the piezoelectric film. The insulation layer is provided on the support substrate. At least a portion of the wiring electrode is provided on the insulation layer. The wiring electrode is electrically connected to the IDT electrode. The external connection electrode is electrically connected to the wiring electrode. The external connection electrode and the piezoelectric film do not overlap each other in a plan view in a thickness direction of the support substrate. The elastic wave device is mounted on the mounting substrate via the external connection electrode. The support substrate is a silicon substrate, a germanium substrate, or a diamond substrate. A surface on the piezoelectric film side of the support substrate is a {100} plane. 
     The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of an electronic component module according to a first preferred embodiment of the present invention. 
         FIG. 2  is a plan view of an elastic wave device in the electronic component module, in which a cover is omitted. 
         FIG. 3  is a schematic diagram for explaining a crystal plane of silicon. 
         FIG. 4  is a cross-sectional view of an electronic component module according to a second preferred embodiment of the present invention. 
         FIG. 5  is a cross-sectional view of an electronic component module according to a third preferred embodiment of the present invention. 
         FIG. 6  is a cross-sectional view of an electronic component module according to a fourth preferred embodiment of the present invention. 
         FIG. 7  is a cross-sectional view of an electronic component module according to a fifth preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, electronic component modules according to preferred embodiments will be described with reference to the accompanying drawings. 
     Note that  FIGS. 1 to 7  are schematic drawings, and therefore the ratio of size, thickness, or other dimensions of each element in the drawings does not necessarily indicate the actual ratio of size, thickness, or other dimensions of the element. 
     First Preferred Embodiment 
     Hereinafter, an electronic component module  100  according to a first preferred embodiment of the present invention will be described with reference to the drawings. 
     As illustrated in  FIG. 1  and  FIG. 2 , the electronic component module  100  according to the first preferred embodiment includes an elastic wave device  1  and a mounting substrate  2 . The elastic wave device  1  is mounted on the mounting substrate  2 .  FIG. 1 , in which the elastic wave device  1  is illustrated, is a cross-sectional view corresponding to a cross section taken along a line X-X in  FIG. 2 . In  FIG. 2 , a cover  18  (see  FIG. 1 ), which will be described later, is not illustrated. 
     The elastic wave device  1  includes a support substrate  11 , a piezoelectric film  122 , an interdigital transducer (IDT) electrode  13 , an insulation layer  16 , a wiring electrode  15 , and a plurality of (two) external connection electrodes  142 . The piezoelectric film  122  is provided on the support substrate  11 . Here, in the elastic wave device  1 , the piezoelectric film  122  is indirectly provided on the support substrate  11 . The IDT electrode  13  is provided on the piezoelectric film  122 . The phrase “provided on the piezoelectric film  122 ” means a case of being directly provided on the piezoelectric film  122  and a case of being indirectly provided on the piezoelectric film  122 . The insulation layer  16  is provided on the support substrate  11 . Here, the phrase “provided on the support substrate  11 ” means a case of being directly provided on the support substrate  11  and a case of being indirectly provided on the support substrate  11 . The wiring electrode  15  is electrically connected to the IDT electrode  13 , and at least a portion of the wiring electrode  15  is provided on the insulation layer  16 . Here, the phrase “provided on the insulation layer  16 ” means a case of being directly provided on the insulation layer  16  and a case of being indirectly provided on the insulation layer  16 . The external connection electrode  142  is electrically connected to the wiring electrode  15 . The external connection electrode  142  and the piezoelectric film  122  do not overlap each other in a plan view in a thickness direction of the support substrate  11 . The external connection electrode  142  is electrically connected to the wiring electrode  15 . The elastic wave device  1  is mounted on the mounting substrate  2  via the external connection electrode  142 . The elastic wave device  1  includes a functional film  12  including at least the piezoelectric film  122  and provided on the support substrate  11  between the support substrate  11  and the IDT electrode  13 . 
     In addition, the elastic wave device  1  further includes a spacer layer  17  and the cover  18 . At least a portion of the spacer layer  17  is provided on the insulation layer  16 . Here, the phrase “provided on the insulation layer  16 ” means a case of being directly provided on the insulation layer  16  and a case of being indirectly provided on the insulation layer  16 . The spacer layer  17  is provided in an outer side portion of the IDT electrode  13  in a plan view in the thickness direction of the support substrate  11 . The spacer layer  17  includes a through-hole  173 . The cover  18  is provided on the spacer layer  17 . Here, the phrase “provided on the spacer layer  17 ” means a case of being directly provided on the spacer layer  17  and a case of being indirectly provided on the spacer layer  17 . The cover  18  is provided on the spacer layer  17  and closes the through-hole  173  of the spacer layer  17 . 
     In the electronic component module  100 , the elastic wave device  1  is electrically and mechanically connected to the mounting substrate  2 . In the electronic component module  100 , a coefficient of linear expansion of the support substrate  11  is different from that of the mounting substrate  2 . In other words, the mounting substrate  2  has a coefficient of linear expansion different from that of the support substrate  11 . 
     In addition, the electronic component module  100  according to the first preferred embodiment further includes a protective layer  3  to protect the elastic wave device  1 . 
     Next, elements of the elastic wave device  1  will be described with reference to the drawings. 
     As illustrated in  FIG. 1 , the support substrate  11  supports a multilayer body including the piezoelectric film  122  and the IDT electrode  13 . The support substrate  11  includes a first main surface  111  and a second main surface  112  on the opposite sides to each other in a thickness direction D 1  thereof. The first main surface  111  and the second main surface  112  are back to back with each other. Although a shape in a plan view of the support substrate  11  (an outer circumferential shape of the support substrate  11  when viewed from the thickness direction D 1 ) is preferably rectangular or substantially rectangular, the support substrate  11  is not limited to a rectangular substantially rectangular shape and may have, for example, a square or substantially square shape. The support substrate  11  is preferably a crystal substrate, for example. Specifically, the support substrate  11  is preferably a crystal substrate having a cubic crystal structure, for example. As an example, the support substrate  11  is a silicon substrate. A surface on the piezoelectric film  122  side (the first main surface  111 ) of the support substrate  11  is a (100) plane. The (100) plane is orthogonal or substantially orthogonal to a crystal axis of [100] in the crystal structure of silicon having a diamond structure as illustrated in  FIG. 3 . In  FIG. 3 , eighteen spheres are silicon atoms. The phrase “the first main surface  111  of the support substrate  11  is a (100) plane” means that the first main surface  111  of the support substrate  11  includes not only the (100) plane but also a crystal plane with an off angle from the (100) plane being greater than about 0 degrees and equal to or smaller than about five degrees. In the silicon substrate, since the (100) plane, a (001) plane, and a (010) plane are crystal planes equivalent to each other, the phrase “a surface on the piezoelectric film  122  side (the first main surface  111 ) of the support substrate  11  is a (100) plane” means that the first main surface  111  on the piezoelectric film  122  side of the support substrate  11  is a {100} plane. The support substrate  11  defines a high acoustic velocity support substrate in which bulk waves propagate at a higher acoustic velocity than an acoustic velocity of elastic waves propagating in the piezoelectric film  122 . As a crystal substrate having a crystal structure, the support substrate  11  may preferably be made of, for example, a germanium substrate, a diamond substrate, or other suitable substrate, in addition to the silicon substrate. Therefore, the material of the support substrate  11  is not limited to silicon, and may be germanium, diamond, or other suitable material, for example. 
     The IDT electrode  13  may be made of an appropriate metal material, such as, for example, aluminum (Al), copper (Cu), platinum (Pt), gold (Au), silver (Ag), titanium (Ti), nickel (Ni), chromium (Cr), molybdenum (Mo), tungsten (W) or an alloy containing any one of these metals as a main ingredient. Further, the IDT electrode  13  may have a structure in which a plurality of metal films made of the above metals or alloys are laminated. 
     As illustrated in  FIG. 2 , the IDT electrode  13  includes a pair of busbars  131  and  132  (hereinafter, also referred to as a first busbar  131  and a second busbar  132 ), a plurality of electrode fingers  133  (hereinafter, also referred to as first electrode fingers  133 ) and a plurality of electrode fingers  134  (hereinafter, also referred to as second electrode fingers  134 ). 
     The first busbar  131  and the second busbar  132  each have an elongated shape denoting one direction (second direction) orthogonal or substantially orthogonal to the thickness direction D 1  of the support substrate  11  (first direction) as a longitudinal direction thereof. In the IDT electrode  13 , the first busbar  131  and the second busbar  132  oppose each other in a third direction orthogonal or substantially orthogonal to both the thickness direction D 1  of the support substrate  11  (first direction) and the second direction. 
     The plurality of first electrode fingers  133  are connected to the first busbar  131  and extend toward the second busbar  132 . Here, the plurality of first electrode fingers  133  extend, from the first busbar  131 , along a direction (third direction) orthogonal or substantially orthogonal to the longitudinal direction (second direction) of the first busbar  131 . The leading ends of the plurality of first electrode fingers  133  and the second busbar  132  are separate from each other. For example, each of the plurality of first electrode fingers  133  preferably has the same or substantially the same length and the same or substantially the same width. 
     The plurality of second electrode fingers  134  are connected to the second busbar  132  and extend toward the first busbar  131 . Here, the plurality of second electrode fingers  134  extend, from the second busbar  132 , along a direction orthogonal or substantially orthogonal to the longitudinal direction of the second busbar  132 . Each leading end of the plurality of second electrode fingers  134  is separate from the first busbar  131 . For example, each of the plurality of second electrode fingers  134  preferably has the same or substantially the same length and the same or substantially the same width. In the example in  FIG. 2 , the length and width of each of the plurality of second electrode fingers  134  are the same or substantially the same as the length and width of each of the plurality of first electrode fingers  133 . 
     In the IDT electrode  13 , the plurality of first electrode fingers  133  and the plurality of second electrode fingers  134  are alternately aligned, one by one, separate from each other in a direction orthogonal or substantially orthogonal to an opposing direction in which the first busbar  131  and the second busbar  132  oppose each other. Accordingly, the first electrode finger  133  and the second electrode finger  134  adjacent to each other in the longitudinal direction of the first busbar  131  are separated from each other. An electrode finger period of the IDT electrode  13  refers to a distance between the sides corresponding to each other of the first electrode finger  133  and the second electrode finger  134  adjacent to each other. A group of electrode fingers including the plurality of first electrode fingers  133  and the plurality of second electrode fingers  134  are only required to have a configuration in which the plurality of first electrode fingers  133  and the plurality of second electrode fingers  134  are aligned separate from each other in the second direction, and may have a configuration in which the plurality of first electrode fingers  133  and the plurality of second electrode fingers  134  are not alternately aligned separate from each other. For example, a region in which the first electrode fingers  133  and the second electrode fingers  134  are alternately aligned, one by one, separate from each other, and a region in which two of the first electrode fingers  133  or the second electrode fingers  134  are aligned in the second direction may be mixed. 
     The functional film  12  includes a low acoustic velocity film  121  in which bulk waves propagate at a lower acoustic velocity than an acoustic velocity of the elastic waves propagating in the piezoelectric film  122  and the piezoelectric film  122  directly or indirectly laminated on the low acoustic velocity film  121 . The piezoelectric film  122  is indirectly laminated on the support substrate  11  defining a high acoustic velocity support substrate. In this case, the low acoustic velocity film  121  is between the support substrate  11  defining the high acoustic velocity support substrate and the piezoelectric film  122 , thus decreasing the acoustic velocity of the elastic waves. Energy of elastic waves is intrinsically concentrated in a medium of low acoustic velocity. Due to this, the elastic wave device  1  improves an effect of confining the elastic wave energy into the piezoelectric film  122  and the IDT electrode  13  in which the elastic waves are excited. Therefore, the elastic wave device  1  is able to reduce loss and increase a Q value as compared with a case in which the low acoustic velocity film  121  is not provided. The functional film  12  may include, for example, a close contact layer interposed between the low acoustic velocity film  121  and the piezoelectric film  122  as another film other than the low acoustic velocity film  121  and the piezoelectric film  122 . With this structure, it is possible to improve the adhesion between the low acoustic velocity film  121  and the piezoelectric film  122 . The close contact layer is preferably made of, for example, resin (epoxy resin, polyimide resin, or other suitable resin), metal, or other suitable material. Further, the functional film  12  may include, but not limited to the close contact layer, a dielectric film at any one of the following positions: a position between the low acoustic velocity film  121  and the piezoelectric film  122 , a position on the piezoelectric film  122 , and a position under the low acoustic velocity film  121 . 
     The piezoelectric film  122  is preferably made of, for example, any one of lithium tantalate (LiTaO 3 ), lithium niobate 
     (LiNbO 3 ), zinc oxide (ZnO), aluminum nitride (AlN) or lead zirconate titanate (PZT). 
     The low acoustic velocity film  121  is preferably made of, for example, any one of silicon oxide, glass, silicon oxynitride, tantalum oxide, a compound in which fluorine, carbon or boron is added to silicon oxide or a material including any one of the above materials as a main ingredient. 
     In the case in which the low acoustic velocity film is made of silicon oxide, it is possible to improve the temperature characteristics. The elastic coefficient of lithium tantalate has negative temperature characteristics, while the elastic coefficient of silicon oxide has positive temperature characteristics. Accordingly, in the elastic wave device  1 , the absolute value of the temperature coefficient of frequency (TCF) is able to be made small. In addition, the specific acoustic impedance of silicon oxide is smaller than the specific acoustic impedance of lithium tantalate. Therefore, in the elastic wave device  1 , both an increase in the electromechanical coupling coefficient, in other words, an expansion of the fractional bandwidth, and an improvement in the temperature coefficient of frequency is able to be achieved. 
     It is preferable that the film thickness of the piezoelectric film  122  is equal to or less than about  3 . 5 λ, for example, where λ is a wave length of the elastic wave determined by the electrode finger period of the IDT electrode  13 . This is because the Q value becomes high. Further, by setting the film thickness of the piezoelectric film  122  to be equal to or less than about 2.5λ, for example, the temperature coefficient of frequency is improved. Further, by setting the film thickness of the piezoelectric film  122  to be equal to or less than about 1.5λ, for example, the acoustic velocity is easily adjusted. 
     It is preferable that the film thickness of the low acoustic velocity film  121  is equal to or less than about 2.0λ, for example, where λ is a wave length of the elastic wave determined by the electrode finger period of the IDT electrode  13 . By setting the film thickness of the low acoustic velocity film  121  to be equal to or less than about 2.0λ, for example, the film stress is able to be reduced, and as a result, warpage of a wafer including a silicon wafer defining a base member of the support substrate  11  at the time of manufacturing is able to be reduced, thus making it possible to improve the non-defective product ratio and stabilize the characteristics. 
     The wiring electrode  15  electrically connects the external connection electrode  142  and the IDT electrode  13 . The wiring electrode  15  may preferably be made of, for example, an appropriate metal material such as aluminum, copper, platinum, gold, silver, titanium, nickel, chromium, molybdenum, tungsten or an alloy containing any one of these metals as a main ingredient. Further, the wiring electrode  15  may include a plurality of metal films made of these metals or alloys is layered. 
     The wiring electrode  15  overlaps a portion of the IDT electrode  13 , a portion of the piezoelectric film  122 , and a portion of the insulation layer  16  in the thickness direction of the support substrate  11 . The external connection electrode  142  is provided on a section  151  of the wiring electrode  15  on the insulation layer  16 . The wiring electrode  15  is positioned inside the outer circumference of the insulation layer  16  in a plan view. 
     The insulation layer  16  has an electrically insulative property. As illustrated in  FIGS. 1 and 2 , the insulation layer  16  is provided along the outer circumference of the support substrate  11  on the first main surface  111  of the support substrate  11 . The insulation layer  16  surrounds the side surface of the piezoelectric film  122 . Here, in the elastic wave device  1 , the insulation layer  16  surrounds the side surface of the functional film  12 . The insulation layer  16  preferably has a frame shape or a substantial frame shape (for example, a rectangular or substantially rectangular frame shape) in a plan view. A portion of the insulation layer  16  overlaps with an outer circumference portion of the piezoelectric film  122  in the thickness direction D 1  of the support substrate  11 . Here, in the elastic wave device  1 , the above portion of the insulation layer  16  overlaps with an outer circumference portion of the functional film  12  in the thickness direction D 1  of the support substrate  11 . The side surface of the piezoelectric film  122  is covered with the insulation layer  16 . Here, the side surface of the functional film  12  is covered with the insulation layer  16 . 
     The material of the insulation layer  16  is preferably, for example, synthetic resin, such as epoxy resin or polyimide. A difference between the coefficient of linear expansion of the insulation layer  16  and the coefficient of linear expansion of the support substrate  11  is larger than a difference between the coefficient of linear expansion of the piezoelectric film  122  and the coefficient of linear expansion of the support substrate  11 . 
     The spacer layer  17  includes the through-hole  173 . The spacer layer  17  is provided in an outer side portion of the IDT electrode  13  and surrounds the IDT electrode  13 , in a plan view in the thickness direction of the support substrate  11 . The spacer layer  17  is provided along the outer circumference of the support substrate  11  in a plan view in the thickness direction of the support substrate  11 . The spacer layer  17  preferably has a frame shape or a substantially frame shape in a plan view. The outer circumferential shape and the inner circumferential shape of the spacer layer  17  are preferably, for example, rectangular or substantially rectangular. The spacer layer  17  overlaps the insulation layer  16  in the thickness direction D 1  of the support substrate  11 . The outer circumferential shape of the spacer layer is smaller than the outer circumferential shape of the insulation layer  16 . The inner circumferential shape of the spacer layer  17  is larger than the inner circumferential shape of the insulation layer  16 . A portion of the spacer layer  17  also covers the wiring electrode  15  on a surface of the insulation layer  16 . The spacer layer  17  includes a first section directly provided on the surface of the insulation layer  16 , and a second section indirectly provided on the surface of the insulation layer  16  with the wiring electrode  15  interposed therebetween. Here, the first section is provided along the entire or substantially the entire circumference of the surface of the insulation layer  16 . 
     The spacer layer  17  has an electrically insulative property. The material of the spacer layer  17  is preferably, for example, synthetic resin, such as epoxy resin or polyimide. It is preferable that the main ingredient of the material of the spacer layer  17  and the main ingredient of the material of the insulation layer  16  be the same, and it is more preferable that the material of the spacer layer  17  and the material of the insulation layer  16  be the same. 
     A total thickness of the thickness of the spacer layer  17  and the thickness of the insulation layer  16  is larger than a total thickness of the thickness of the functional layer  12  and the thickness of the IDT electrode  13 . 
     The cover  18  preferably has a flat or substantially flat plate shape, for example. Although the shape of the cover  18  in a plan view (an outer circumferential shape when viewed from the thickness direction D 1  of the support substrate  11 ) is rectangular or substantially rectangular, the shape is not limited to a rectangle and may be, for example, square or substantially square. The outer circumferential shape of the cover  18  has the same or substantially the same size as the outer circumferential shape of the support substrate  11 . The cover  18  is disposed on the spacer layer  17  so as to close the through-hole  173  of the spacer layer  17 . The cover  18  is separated from the IDT electrode  13  in the thickness direction D 1 . In the elastic wave device  1 , the cover  18  has an electrically insulative property. The material of the cover  18  is preferably, for example, synthetic resin, such as epoxy resin or polyimide. It is preferable that the main ingredient of the material of the cover  18  and the main ingredient of the material of the spacer layer  17  be the same, and it is more preferable that the material of the cover  18  and the material of the spacer layer  17  be the same. 
     The elastic wave device  1  includes a space S 1  surrounded by the cover  18 , the spacer layer  17 , the insulation layer  16 , and the multilayer body (the multilayer body including the piezoelectric film  122  and the IDT electrode  13 ) on the support substrate  11 . In the elastic wave device  1 , gas is contained in the space S 1 . The gas is preferably, for example, air, an inert gas (e.g., a nitrogen gas) or other suitable gas. 
     The elastic wave device  1  includes a plurality of (two or more) external connection electrodes  142 . The external connection electrode  142  is to be electrically connected with the mounting substrate  2  in the elastic wave device  1 . In addition, the elastic wave device  1  may include a plurality of (two) mounting electrodes  19 , which are not electrically connected to the IDT electrode  13  in some case. The mounting electrode  19  improves the parallelism of the elastic wave device  1  with respect to the mounting substrate  2 , and is different from the electrode that provides electrical connection. In other words, the mounting electrode  19  prevents a situation in which the elastic wave device  1  is mounted and is inclined with respect to the mounting substrate  2 , and is not absolutely necessary depending on the number and arrangement of the external connection electrodes  142 , the outer circumferential shape of the elastic wave device  1 , and other factors. 
     In the elastic wave device  1 , in a plan view in the thickness direction D 1  of the support substrate  11 , two external connection electrodes  142  are respectively disposed in two of the four corners of the cover  18  diagonally opposing each other, and two mounting electrodes  19  are respectively disposed in the remaining two corners of the four corners. In the elastic wave device  1 , in a plan view in the thickness direction D 1  of the support substrate  11 , none of the two external connection electrodes  142  and two mounting electrodes  19  overlap with the piezoelectric film  122 . 
     The elastic wave device  1  includes a penetration electrode  141  penetrating through the spacer layer  17  and the cover  18  in the thickness direction D 1  of the support substrate  11 . The penetration electrode  141  is provided on the wiring electrode  15 , and is electrically connected to the wiring electrode  15 . The penetration electrode  141  defines an under bump metal layer. Further, the external connection electrode  142  is provided on the penetration electrode  141 . The external connection electrode  142  is preferably, for example, a bump. The external connection electrode  142  has conductivity. The external connection electrode  142  is bonded to the penetration electrode  141 , and is electrically connected to the penetration electrode  141 . Further, the elastic wave device  1  includes a penetration electrode penetrating through the spacer layer  17  and the cover  18  in the thickness direction D 1  of the support substrate  11  directly below the mounting electrode  19 . The mounting electrode  19  is preferably, for example, a bump provided on the penetration electrode. 
     The penetration electrode  141  may be made of an appropriate metal material such as copper, nickel, or an alloy mainly containing any one of these metals, for example. The external connection electrode  142  may be made of, for example, solder, gold, copper, or other suitable material. The penetration electrode directly below the mounting electrode  19  is preferably made of the same material as that of the penetration electrode  141  directly below the external connection electrode  142 . Further, the mounting electrode  19  is preferably made of the same material as that of the external connection electrode  142 . 
     The elastic wave device  1  is mounted on the mounting substrate  2  via the external connection electrode  142 . In the electronic component module  100 , a single elastic wave device  1  is mounted on the mounting substrate  2 . The mounting substrate  2  is larger in size than the elastic wave device  1  in a plan view in the thickness direction D 1  of the support substrate  11 . 
     The mounting substrate  2  includes a support body  21 , a plurality of (two) first conductor sections  23  supported by the support body  21 , and a plurality of (two) second conductor sections  25  supported by the support body  21 . In addition, the mounting substrate  2  further includes a plurality of (two) penetration electrodes  24  electrically connecting the plurality of (two) first conductor sections  23  and the plurality of (two) second conductor sections  25  on a one-to-one basis. The second conductor section  25  is used to electrically connect the electronic component module  100  to a circuit board or other suitable substrate. 
     The support body  21  has an electrically insulative property. The support body  21  preferably has a flat or substantially flat plate shape and includes a first main surface  211  and a second main surface  212  that are positioned on the opposite sides to each other in a thickness direction thereof. The first main surface  211  and the second main surface  212  are back to back with each other. An outer circumferential shape of the support body  21  is preferably, for example, rectangular or substantially rectangular. 
     The first conductor section  23  is provided on the first main surface  211  of the support body  21 . The first conductor section  23  is a conductive layer to which the external connection electrode  142  of the elastic wave device  1  is electrically connected. The material of the first conductor section  23  is preferably, for example, copper or other suitable material. The first conductor section  23  overlaps with the external connection electrode  142  in the thickness direction D 1  of the support substrate  11  of the elastic wave device  1 . The external connection electrode  142  is interposed between the penetration electrode  141  and the first conductor section  23 . A conductive layer to which the mounting electrode  19  of the elastic wave device  1  is connected is also provided on the first main surface  211  of the support body  21 . The conductive layer overlaps with the mounting electrode  19  in the thickness direction D 1  of the support substrate  11  of the elastic wave device  1 . The thickness of this conductive layer is preferably the same or substantially the same as that of the first conductor section  23 . The material of this conductive layer is preferably the same or substantially the same as that of the first conductor section  23 . 
     The second conductor section  25  is provided on the second main surface  212  of the support body  21 . The first conductor section  23  is electrically connected to the second conductor section  25  via the penetration electrode  24 . The material of the second conductor section  25  is preferably, for example, copper or other suitable material. 
     As an example, the mounting substrate  2  is preferably a printed wiring substrate. The coefficient of linear expansion of the printed wiring substrate is preferably, for example, about 15 ppm/° C. The printed wiring substrate is preferably made of, for example, a glass fabric epoxy resin copper-clad laminate. 
     The support body  21  is preferably an insulation substrate in the printed wiring substrate. The insulation substrate has an electrically insulative property. 
     The first conductor section  23  and the second conductor section  25  include copper foil of the printed wiring substrate. 
     In the electronic component module  100 , the elastic wave device  1  mounted on the mounting substrate  2  is covered with the protective layer  3 . In the electronic component module  100 , the second main surface  112  and side surfaces  113  of the support substrate  11  of the elastic wave device  1  are covered with the protective layer  3 . The material of the protective layer  3  is preferably, for example, synthetic resin, such as epoxy resin or polyimide. The protective layer  3  defines and functions as a sealing layer to seal the elastic wave device  1  on the mounting substrate  2 . The protective layer  3  preferably has a rectangular or substantially rectangular parallelepiped shape, for example. A portion of the protective layer  3  is also provided around the external connection electrode  142  between the cover  18  of the elastic wave device  1  and the mounting substrate  2 . In other words, a portion of the protective layer  3  defines an under-fill portion. The electronic component module  100  may be surface-mounted on a mother board or other substrate different from the mounting substrate  2 . In the electronic component module  100 , the mounting substrate  2  and the protective layer  3  define a package that protects the elastic wave device  1  and allows the connection with an external electric circuit or other circuit. The package in the electronic component module  100  is preferably a surface mount package, for example. 
     In a plan view in the thickness direction D 1  of the support substrate  11 , an outer circumferential shape of the protective layer  3  is preferably the same or substantially the same size as the outer circumferential shape of the mounting substrate  2 . 
     Hereinafter, a non-limiting example of a manufacturing method for the elastic wave device  1  will be briefly described. 
     In the manufacturing method for the elastic wave device  1 , a silicon wafer to be a base member of the support substrate  11  of each of a plurality of elastic wave devices  1  is prepared first. 
     In the manufacturing method for the elastic wave device  1 , after the functional film  12  including the piezoelectric film  122  is formed on one main surface of the silicon wafer, the IDT electrode  13 , the insulation layer  16 , the wiring electrode  15 , and the spacer layer  17  are sequentially formed; thereafter, the cover  18  is bonded to the spacer layer  17  to close the through-hole  173  of the spacer layer  17 ; subsequently, a through-hole is formed in a region of the cover  18  and the spacer layer  17  at which the penetration electrode  141  is expected to be formed, the penetration electrode  141  is formed to fill this through-hole, and then the external connection electrode  142  is formed on the penetration electrode  141 . Thus, with the manufacturing method for the elastic wave device  1 , a wafer in which the plurality of elastic wave devices  1  are formed on the silicon wafer is obtained. The one main surface of the silicon wafer corresponds to the first main surface  111  of the support substrate  11  defined by a silicon substrate. 
     In the manufacturing method for the elastic wave device  1 , by performing a cutting process in which the wafer is cut with a dicing machine, the plurality of elastic wave devices  1  are obtained from a single wafer. In the cutting process, a dicing saw or other suitable device is preferably used, for example. 
     In a manufacturing method for the electronic component module  100 , the elastic wave device  1  is mounted on the mounting substrate  2 , and then the protective layer  3  is formed to cover the elastic wave device  1  on the mounting substrate  2 . As a result, the electronic component module  100  is formed. 
     In an electronic component module  100  according to Working Example 1 of the first preferred embodiment, a support substrate  11  is a silicon substrate, and a first main surface  111  of the support substrate  11  is a (100) plane. The coefficient of linear expansion of the support substrate  11  is preferably about 4 ppm/° C., for example. 
     An electronic component module according to a comparative example has the same or substantially the same basic structure as that of the electronic component module  100  according to Working Example 1, and is different from the electronic component module  100  in that, in place of the support substrate  11  of the electronic component module  100  according to Working Example 1, a support substrate made of a silicon substrate whose first main surface is a (111) plane is provided. 
     Hereinafter, a result of performing a thermal shock test on both a sample of the electronic component module  100  according to Working Example 1 and a sample of the electronic component module according to the comparative example will be described. Here, the thermal shock test is a two-liquid tank temperature rapid change test conforming to JIS C 60068-2-14 and IEC 60068-2-14. 
     In the electronic component module  100  according to Working Example 1, preferably, for example, the material of a low acoustic velocity film  121  was silicon oxide, the material of a piezoelectric film  122  was lithium tantalate (LiTaO 3 ), the material of an IDT electrode  13  was aluminum (Al), the material of an insulation layer  16  was an epoxy resin, the material of a spacer layer  17  was an epoxy resin, the material of a cover  18  was an epoxy resin, the material of a penetration electrode  141  was copper (Cu), an external connection electrode  142  was defined by a bump, and the material of the bump was solder. Further, in the electronic component module  100  according to Working Example 1, preferably, for example, the thickness of the silicon substrate was set to about 125 μm, the thickness of the low acoustic velocity film  121  was set to about 600 nm, the thickness of the piezoelectric film  122  was set to about 600 nm, and the thickness of the IDT electrode  13  was set to about 150 nm. In the electronic component module  100  according to Working Example 1, preferably, for example, the coefficient of linear expansion of the support substrate  11  was about 4 ppm/° C., and the coefficient of linear expansion of a mounting substrate  2  was about 15 ppm/° C. Here, the coefficient of linear expansion of the mounting substrate  2  refers to a coefficient of linear expansion of an insulation substrate in a printed wiring substrate defining the mounting substrate  2  (a support body  21  in the mounting substrate  2 ). 
     In the electronic component module according to the comparative example, a crack, starting from a side surface of the support substrate and extending along the first main surface of the support substrate, was generated in the vicinity of the first main surface of the support substrate. In contrast, in the electronic component module  100  according to Working Example 1, no crack was generated in the support substrate  11 . 
     In addition, in an electronic component module  100  according to Working Example 2, preferably, for example, a low temperature co-fired ceramics (LTCC) substrate, instead of the printed wiring substrate, was used as a mounting substrate  2 . The coefficient of linear expansion of the mounting substrate  2  in this case was preferably about 10 ppm/° C., for example. 
     When a thermal shock test was performed on a sample of the electronic component module  100  according to Working Example 2 as one of reliability evaluations, no crack was generated in a support substrate  11  of the electronic component module  100  according to Working Example 2. 
     The electronic component module  100  according to the first preferred embodiment includes the elastic wave device  1  and the mounting substrate  2 . The elastic wave device  1  is mounted on the mounting substrate  2 . The elastic wave device  1  includes the support substrate  11 , the piezoelectric film  122 , the IDT electrode  13 , the insulation layer  16 , the wiring electrode  15 , and the external connection electrode  142 . The support substrate  11  is a crystal substrate. The piezoelectric film  122  is indirectly provided on the support substrate  11 . The IDT electrode  13  is provided on the piezoelectric film  122 . The insulation layer  16  is provided on the support substrate  11 . At least a portion of the wiring electrode  15  is provided on the insulation layer  16 . The wiring electrode  15  is electrically connected to the IDT electrode  13 . The external connection electrode  142  and the piezoelectric film  122  do not overlap each other in a plan view in the thickness direction D 1  of the support substrate  11 . The elastic wave device  1  is mounted on the mounting substrate  2  via the external connection electrode  142 . The mounting substrate  2  has a coefficient of linear expansion different from that of the support substrate  11 . A surface on the piezoelectric film  122  side (the first main surface  111 ) of the support substrate  11  is a {100} plane. 
     In the electronic component module  100  according to the first preferred embodiment, since the external connection electrode  142  and the piezoelectric film  122  do not overlap each other in a plan view in the thickness direction of the support substrate  11 , it is possible to prevent a situation in which force is applied from the external connection electrode  142  to the piezoelectric film  122  during the process of forming the external connection electrode  142  at the time of manufacturing, and thus it is possible to prevent the occurrence of cracking, chipping, or other damage in the piezoelectric film  122 . In addition, in the electronic component module  100  according to the first preferred embodiment, since the coefficient of linear expansion of the support substrate  11  and that of the mounting substrate  2  are different from each other, thermal stress due to the difference in coefficient of linear expansion between the support substrate  11  and the mounting substrate  2  is applied to the support substrate  11 . However, since the surface on the piezoelectric film  122  side (the first main surface  111 ) of the support substrate  11  is a {100} plane, even if the thermal stress due to the difference in coefficient of linear expansion between the support substrate  11  and the mounting substrate  2  is applied to the support substrate  11 , it is possible to prevent the generation of a crack in the support substrate  11  because each of the side surfaces  113  of the support substrate  11  has a plane orientation unlikely to be separated by the generation of a crack (because the silicon atoms in the crystal structure of the support substrate  11  are arranged such that a portion of the support substrate  11  is unlikely to be separated by the generation of a crack) in comparison with a case in which the surface on the piezoelectric film  122  side (the first main surface  111 ) of the support substrate  11  is a (111) plane. 
     Note that, in the electronic component module  100  according to the first preferred embodiment, the piezoelectric film  122  (as well as the functional film  12  including the piezoelectric film  122 ) is not present at a position overlapping with the external connection electrode  142  in a plan view in the thickness direction D 1  of the support substrate  11 . Further, in a case in which a structure in which the piezoelectric film  122  (as well as the functional film  12  including the piezoelectric film  122 ) is present at the position overlapping with the external connection electrode  142  in a plan view in the thickness direction D 1  of the support substrate  11  is taken as a comparative example, when a difference in coefficient of linear expansion between the insulation layer  16  and the support substrate  11  is greater than a difference in coefficient of linear expansion between the piezoelectric film  122  and the support substrate  11 , a crack is more likely to be generated in the support substrate  11  in the electronic component module  100  than in the case of the comparative example. 
     The reason for this is as follows: in the case in which the insulation layer  16  is made of a material that causes a difference in coefficient of linear expansion between the insulation layer  16  and the support substrate  11  to be larger than a difference in coefficient of linear expansion between the piezoelectric film  122  and the support substrate  11 , when a thermal shock is applied in the electronic component module  100 , for example, as in a case of the thermal shock test being performed, not only the thermal stress due to the difference in coefficient of linear expansion between the support substrate  11  and the mounting substrate  2 , but also the thermal stress due to the difference in coefficient of linear expansion between the support substrate  11  and the insulation layer  16  is applied to the support substrate  11 . On the other hand, in the comparative example, when the thermal shock is applied, not only the thermal stress due to the difference in coefficient of linear expansion between the support substrate  11  and the mounting substrate  2 , but also the thermal stress due to the difference in coefficient of linear expansion between the support substrate  11  and the piezoelectric film  122  is applied to the support substrate  11 . However, since the thermal stress due to the difference in coefficient of linear expansion between the support substrate  11  and the piezoelectric film  122  is smaller than the thermal stress due to the difference in coefficient of linear expansion between the support substrate  11  and the insulation layer  16 , cracking is more likely to occur in the support substrate  11  in the electronic component module  100  than in the case of the comparative example. 
     As described above, even in this case, in the electronic component module  100 , since the surface on the piezoelectric film  122  side (the first main surface  111 ) is a (100) plane, as with the support substrate  11 , it is possible to prevent the occurrence of cracking in the support substrate  11 . 
     In addition, in the electronic component module  100  according to the first preferred embodiment, the mounting substrate  2  is a printed wiring substrate. With this, in the electronic component module  100 , it is possible to reduce the cost as compared with a case where the mounting substrate  2  is formed of an LTCC substrate. 
     In addition, in the electronic component module  100  according to the first preferred embodiment, the piezoelectric film  122  (as well as the functional film  12  including the piezoelectric film  122 ) is provided inside the outer circumference of the support substrate  11  in a plan view in the thickness direction D 1  of the support substrate  11 . With this structure, in the electronic component module  100 , it is possible to prevent a situation in which the piezoelectric film  122  (as well as the functional film  12  including the piezoelectric film  122 ) is separated from the support substrate  11  side during the cutting process with a dicing machine at the time of manufacturing, and thus, it is possible to improve the reliability. 
     Moreover, the electronic component module  100  according to the first preferred embodiment further includes the spacer layer  17 , the cover  18 , and the penetration electrode  141 . At least a portion of the spacer layer  17  is provided on the insulation layer  16 . The spacer layer  17  is provided in the outer side portion of the IDT electrode  13  in a plan view in the thickness direction D 1  of the support substrate  11 . The cover  18  is provided on the spacer layer  17 . The penetration electrode  141  is provided on the insulation layer  16  and the wiring electrode  15 . The penetration electrode  141  is electrically connected to the wiring electrode  15 . The penetration electrode  141  penetrates through the spacer layer  17  and the cover  18 . The external connection electrode  142  is electrically connected to the wiring electrode  15  and the penetration electrode  141 . The external connection electrode  142  is provided on the penetration electrode  141  and the cover  18 . 
     Second Preferred Embodiment 
     As illustrated in  FIG. 4 , an electronic component module  100   a  according to a second preferred embodiment of the present invention is different from the electronic component module  100  according to the first preferred embodiment in that an external connection electrode  142   a  is directly provided on a wiring electrode  15 . Regarding the electronic component module  100   a  according to the second preferred embodiment, the same or similar elements as those of the electronic component module  100  according to the first preferred embodiment are denoted by the same reference numerals, and description thereof will be omitted. 
     In the electronic component module  100   a  according to the second preferred embodiment, an elastic wave device  1   a  does not include the spacer layer  17 , the cover  18 , and the penetration electrode  141 , for example, provided in the elastic wave device  1  of the electronic component module  100  according to the first preferred embodiment. Further, in the electronic component module  100   a,  the external connection electrode  142   a  is directly provided on the wiring electrode  15 . The external connection electrode  142   a  is preferably a bump. The material of the bump is preferably, for example, solder, Au, or other suitable material, for example. 
     The electronic component module  100   a  further includes a resist layer  155  covering a peripheral portion of a section  151  of the wiring electrode  15  provided on an insulation layer  16 . In the electronic component module  100   a,  among the section  151  of the wiring electrode  15  provided on the insulation layer  16 , a portion that is not covered with the resist layer  155  defines a pad electrode  152 . The external connection electrode  142   a  is provided on the pad electrode  152  of the wiring electrode  15 . 
     In the electronic component module  100   a  according to the second preferred embodiment, as in the electronic component module  100  according to the first preferred embodiment, since the external connection electrode  142   a  and a piezoelectric film  122  do not overlap each other (separate from each other) in a plan view in the thickness direction of a support substrate  11 , it is possible to prevent a situation in which force from the external connection electrode  142   a  is applied to the piezoelectric film  122 , and thus it is possible to prevent the occurrence of cracking in the piezoelectric film  122 . In addition, since the electronic component module  100   a  according to the second preferred embodiment includes, as the electronic component module  100  according to the first preferred embodiment, a silicon substrate defining the support substrate  11  in which a surface on the piezoelectric film  122  side (first main surface  111 ) is a {100} plane, it is possible to prevent the occurrence of cracking in the support substrate  11  in comparison with a case of including a silicon substrate as the support substrate in which the surface on the piezoelectric film  122  side is a (111) plane. 
     In the electronic component module  100   a  according to the second preferred embodiment, the external connection electrode  142   a  is preferably a bump. The material of the bump is preferably solder or gold, for example. Thus, in the electronic component module  100   a  according to the second preferred embodiment, it is possible to simplify the configuration of the elastic wave device  1   a  as compared with the electronic component module  100  according to the first preferred embodiment. 
     The electronic component module  100   a  according to the second preferred embodiment may include a protective layer, similar to the protective layer  3  of the electronic component module  100  according to the first preferred embodiment, covering the elastic wave device  1   a  on the mounting substrate  2 . 
     Third Preferred Embodiment 
     Hereinafter, an electronic component module  100   b  according to a third preferred embodiment of the present invention will be described with reference to  FIG. 5 . 
     The electronic component module  100   b  according to the third preferred embodiment is different from the electronic component module  100  according to the first preferred embodiment in that it includes, in place of the penetration electrode  141  and the external connection electrode  142  of the electronic component module  100  according to the first preferred embodiment, an external connection electrode  142   b  and a penetration electrode  141   b  penetrating through an insulation layer  16  and a support substrate  11 . Regarding the electronic component module  100   b  according to the third preferred embodiment, the same or similar elements as those of the electronic component module  100  according to the first preferred embodiment will be denoted by the same reference numerals, and description thereof will be omitted. 
     The external connection electrode  142   b  overlaps with a section  151 , among a wiring electrode  15 , that is provided on the insulation layer  16 , in a thickness direction D 1  of the support substrate  11 . The external connection electrode  142   b  is provided on the penetration electrode  141   b  penetrating through the insulation layer  16  and the support substrate  11  in the thickness direction D 1  of the support substrate  11 . An electrically insulative film  114  is interposed between the penetration electrode  141   b  and the support substrate  11 . The electrically insulative film  114  is preferably made of, for example, silicon oxide. The penetration electrode  141   b  is electrically connected to a wiring electrode  15   b.  In short, the penetration electrode  141   b  is electrically connected to an IDT electrode  13  via the wiring electrode  15   b.  The wiring electrode  15   b  covers a portion of a piezoelectric film  122  and a portion of the IDT electrode  13 . The penetration electrode  141   b  may preferably be made of an appropriate metal material, such as copper, nickel or an alloy mainly containing any one of these metals, for example. The external connection electrode  142   b  may preferably be made of, for example, solder, gold, copper or other suitable material. 
     The electronic component module  100   b  according to the third preferred embodiment includes a spacer layer  17   b  and a cover  18   b,  instead of the spacer layer  17  and the cover  18  of the electronic component module  100  according to the first preferred embodiment. 
     The spacer layer  17   b  is provided on the support substrate  11 . More specifically, the spacer layer  17   b  is provided directly on a first main surface  111  of the support substrate  11  without the insulation layer  16  (see  FIG. 1 ) interposed therebetween. The spacer layer  17   b  includes a through-hole  173 . The material of the spacer layer  17   b  is preferably, for example, synthetic resin, such as epoxy resin or polyimide. 
     The thickness of the spacer layer  17   b  is greater than a total thickness of the thickness of a functional film  12  and the thickness of the IDT electrode  13 . 
     The cover  18   b  is provided on the spacer layer  17   b  to close the through-hole  173  of the spacer layer  17   b.  The cover  18   b  is separated from the IDT electrode  13  in the thickness direction D 1  of the support substrate  11 . 
     In the electronic component module  100   b,  a difference in coefficient of linear expansion between the cover  18   b  and the support substrate  11  is smaller than a difference in coefficient of linear expansion between a mounting substrate  2  and the support substrate  11 . The material of the cover  18   b  is preferably silicon, for example. In other words, the cover  18   b  is preferably a silicon substrate. Accordingly, a difference in coefficient of linear expansion between the cover  18   b  and the mounting substrate  2  is the same or substantially the same as the difference in coefficient of linear expansion between the mounting substrate  2  and the support substrate  11 . The cover  18   b  may include, in addition to the silicon substrate, a thin film, such as an insulation film laminated on the silicon substrate. In the electronic component module  100   b,  a surface of the cover  18   b  on the opposite side to a surface on the support substrate  11  side thereof is a {100} plane. The cover  18   b  is formed by cutting, with a dicing machine, a silicon wafer to be a base member of a plurality of covers  18   b . The thickness of the cover  18   b  may be different from or may be the same as the thickness of the support substrate  11 . 
     An elastic wave device  1   b  includes a space S 1   b  surrounded by the cover  18   b,  the spacer layer  17   b,  and a multilayer body (a multilayer body including the piezoelectric film  122  and the IDT electrode  13 ) on the support substrate  11 . In the elastic wave device  1   b , gas is contained in the space S 1   b . The gas is preferably, for example, air, an inert gas (e.g., a nitrogen gas) or other suitable gas. 
     In the electronic component module  100   b  according to the third preferred embodiment, as in the electronic component module  100  according to the first preferred embodiment, the external connection electrode  142   b  and the piezoelectric film  122  do not overlap each other in a plan view in the thickness direction D 1  of the support substrate  11 . With this structure, in the electronic component module  100   b  according to the third preferred embodiment, it is possible to prevent a situation in which force from the external connection electrode  142   b  is applied to the piezoelectric film  122 , and thus, it is possible to prevent the occurrence of cracking, chipping, or other damage in the piezoelectric film  122  during the process of forming the external connection electrode  142   b  at the time of manufacturing. In addition, in the electronic component module  100   b  according to the third preferred embodiment, as in the electronic component module  100  according to the first preferred embodiment, since a surface on the piezoelectric film  122  side (first main surface  111 ) of the support substrate  11  is a {100} plane, it is possible to prevent the occurrence of cracking in the support substrate  11  in comparison with a case in which the surface on the piezoelectric film  122  side of the support substrate  11  is a (111) plane. 
     Moreover, in the electronic component module  100   b,  the difference in coefficient of linear expansion between the cover  18   b  and the support substrate  11  is smaller than the difference in coefficient of linear expansion between the mounting substrate  2  and the support substrate  11 . Thus, in the electronic component module  100   b,  it is possible to further prevent the occurrence of cracking in the support substrate  11 . 
     In the electronic component module  100   b,  the material of the cover  18   b  is preferably silicon, for example. With this structure, in the electronic component module  100   b,  it is possible to make the difference in coefficient of linear expansion between the cover  18   b  and the support substrate  11  be smaller, and thus it is possible to reduce the thermal stress applied from the cover  18   b  to the support substrate  11 . Further, in the electronic component module  100   b,  since the penetration electrode  141   b  penetrates through the support substrate  11 , it is possible to improve the heat dissipation property in comparison with a case in which the penetration electrode  141  penetrates through the spacer layer  17  made of resin and the cover  18  made of resin as in the case of the electronic component module  100  according to the first preferred embodiment. Furthermore, in the electronic component module  100   b,  since the material of the cover  18   b  is silicon, it is possible to improve the mold resistance at the time of molding with resin, for example. 
     In addition, in the electronic component module  100   b,  a surface of the cover  18   b  including the silicon substrate on the opposite side to a surface on the support substrate  11  side thereof is a {100} plane. As a result, in the electronic component module  100   b,  as compared with a case in which the surface of the cover  18   b  is a (111) plane in the cutting process with a dicing machine at the time of manufacturing, for example, the plane orientation is able to be aligned at the support substrate  11  and the cover  18   b,  and therefore, the occurrence of chipping in the cover  18   b  is able to be prevented. 
     Fourth Preferred Embodiment 
     In an electronic component module  100   c  according to a fourth preferred embodiment of the present invention, as illustrated in  FIG. 6 , a functional film  12  in an elastic wave device  1   c  includes a high acoustic velocity film  120 , a low acoustic velocity film  121 , and a piezoelectric film  122 . The high acoustic velocity film  120  is provided directly or indirectly on a support substrate  11 . In the high acoustic velocity film  120 , bulk waves propagate at a higher acoustic velocity than an acoustic velocity of elastic waves propagating in the piezoelectric film  122 . The low acoustic velocity film  121  is provided directly or indirectly on the high acoustic velocity film  120 . In the low acoustic velocity film  121 , bulk waves propagate at a lower acoustic velocity than the acoustic velocity of the elastic waves propagating in the piezoelectric film  122 . The piezoelectric film  122  is provided directly or indirectly on the low acoustic velocity film  121 . Regarding the electronic component module  100   c  according to the fourth preferred embodiment, the same or similar elements as those of the electronic component module  100  according to the first preferred embodiment (see  FIG. 1 ) will be denoted by the same reference numerals, and description thereof will be omitted. 
     In the elastic wave device  1   c  of the electronic component module  100   c  according to the fourth preferred embodiment, the high acoustic velocity film  120  functions so that elastic waves do not leak to a structure under the high acoustic velocity film  120 . 
     With this structure, in the elastic wave device  1   c , energy of elastic waves of a specific mode used to obtain the characteristics of a filter, a resonator or other device is distributed across the entirety or substantially the entirety of the piezoelectric film  122  and the low acoustic velocity film  121 , also distributed across a portion of the high acoustic velocity film  120  on the low acoustic velocity film  121  side, and not distributed on the support substrate  11 . A mechanism to confine the elastic waves by the high acoustic velocity film  120  is a mechanism similar to that for Love waves, which are non-leaky shear horizontal (SH) waves, and is described in, for example, “Introduction to Simulation Technologies for Surface Acoustic Wave Devices”, by Kenya Hashimoto, Realize Corp., pp. 26-28. The above-discussed mechanism is different from a mechanism to confine elastic waves by using a Bragg reflector with an acoustic multilayer film. 
     The high acoustic velocity film  120  is preferably made of, for example, diamond-like carbon, aluminum nitride, aluminum oxide, silicon carbide, silicon nitride, silicon, sapphire, lithium tantalate, lithium niobate, a piezoelectric material such as quartz, various ceramics such as alumina, zirconia, cordierite, mullite, steatite and forsterite, magnesia diamond, a material containing the above materials as a main ingredient or a material containing a mixture of the above materials as a main ingredient. 
     As for the film thickness of the high acoustic velocity film  120 , since the high acoustic velocity film  120  confines elastic waves to the piezoelectric film  122  and the low acoustic velocity film  121 , it is preferable that the film thickness of the high acoustic velocity film  120  is thicker. The functional film  12  may include, for example, a close contact layer or a dielectric film as another film other than the high acoustic velocity film  120 , the low acoustic velocity film  121  and the piezoelectric film  122 . 
     In the electronic component module  100   c  according to the fourth preferred embodiment, as in the electronic component module  100  according to the first preferred embodiment, an external connection electrode  142  and the piezoelectric film  122  do not overlap each other in a plan view in a thickness direction D 1  of the support substrate  11 . With this structure, in the electronic component module  100   c  according to the fourth preferred embodiment, it is possible to prevent a situation in which force from the external connection electrode  142  is applied to the piezoelectric film  122 , and thus it is possible to prevent the occurrence of cracking, chipping, or other damage in the piezoelectric film  122  during the process of forming the external connection electrode  142  at the time of manufacturing. In addition, in the electronic component module  100   c  according to the fourth preferred embodiment, as in the electronic component module  100  according to the first preferred embodiment, since a surface on the piezoelectric film  122  side (first main surface  111 ) of the support substrate  11  is a {100} plane, it is possible to prevent the occurrence of cracking in the support substrate  11  in comparison with a case in which the surface on the piezoelectric film  122  side of the support substrate  11  is a (111) plane. 
     Fifth Preferred Embodiment 
     As illustrated in  FIG. 7 , in an electronic component module  100   d  according to a fifth preferred embodiment of the present invention, the functional film  12  in the elastic wave device  1   c  corresponds to a piezoelectric film  122 . The piezoelectric film  122  is provided directly on a support substrate  11 . Regarding the electronic component module  100   d  according to the fifth preferred embodiment, the same or similar elements as those of the electronic component module  100  according to the first preferred embodiment (see  FIG. 1 ) will be denoted by the same reference numerals, and description thereof will be omitted. 
     The support substrate  11  defines a high acoustic velocity support substrate in which bulk waves propagate at a higher acoustic velocity than an acoustic velocity of elastic waves propagating in the piezoelectric film  122 . The functional film  12  may preferably include, for example, as another film other than the piezoelectric film  122 , a close contact layer or a dielectric film provided on the support substrate  11  side of the piezoelectric film  122 . Further, the functional film  12  may include a dielectric film or other film provided on an IDT electrode  13  side of the piezoelectric film  122 . 
     In the electronic component module  100   d  according to the fifth preferred embodiment, as in the electronic component module  100  according to the first preferred embodiment, an external connection electrode  142  and the piezoelectric film  122  do not overlap each other in a plan view in a thickness direction D 1  of the support substrate  11 . With this structure, in the electronic component module  100   d  according to the fifth preferred embodiment, it is possible to prevent a situation in which force from the external connection electrode  142  is applied to the piezoelectric film  122 , and thus it is possible to prevent the occurrence of cracking, chipping, or other damage in the piezoelectric film  122 , during the process of forming the external connection electrode  142  at the time of manufacturing. In addition, in the electronic component module  100   d  according to the fifth preferred embodiment, as in the electronic component module  100  according to the first preferred embodiment, since a surface on the piezoelectric film  122  side (first main surface  111 ) is a {100} plane as the support substrate  11 , it is possible to prevent the occurrence of cracking in the support substrate  11  in comparison with a case in which the surface on the piezoelectric film  122  side is a (111) plane as the support substrate  11 . 
     Each of the preferred embodiments described above is merely one of various preferred embodiments of the present invention. A variety of modifications may be made to the above-described preferred embodiments in accordance with design or the like as long as the advantageous effects of the present invention are achieved. 
     For example, the printed wiring substrate defining the mounting substrate  2  is not limited to being made of a glass fabric epoxy resin copper-clad laminate, and may be made of, for example, a glass fabric polyimide-based resin copper-clad laminate, a paper epoxy resin copper-clad laminate, a paper glass fabric epoxy resin copper-clad laminate, a glass nonwoven-fabric glass fabric epoxy resin copper-clad laminate, or other suitable materials. 
     Further, the mounting substrate  2  is not limited to a printed wiring substrate, and may be, for example, a low temperature co-fired ceramics (LTCC) substrate. The LTCC substrate is a substrate having been fired at equal to or lower than about 1000° C. (e.g., about 850° C. to about 1000° C.), which is relatively low in temperature as compared with the firing temperature of an alumina substrate. The coefficient of linear expansion of the LTCC substrate is, for example, about 10 ppm/° C. 
     Further, each of the electronic component modules  100 ,  100   a,    100   b,    100   c  and  100   d  is not limited to the configuration in which only the single elastic wave device  1 ,  1   a ,  1   b ,  1   c  or  1   d  is mounted as an electronic component on the mounting substrate  2 , and may include a plurality of elastic wave devices  1 ,  1   a,    1   b,    1   c  or  1   d  that are mounted or the elastic wave device  1 ,  1   a,    1   b,    1   c  or  1   d,  and an electronic component other than the elastic wave devices  1 ,  1   a,    1   b,    1   c  and  1   d  may be mounted together, for example. 
     In addition, the functional film  12  may be provided with an acoustic impedance layer. The acoustic impedance layer is provided between the piezoelectric film  122  and the support substrate  11 . The acoustic impedance layer prevents the leakage of elastic waves excited by the IDT electrode  13  to the support substrate  11 . The acoustic impedance layer has a laminated structure in which at least one high acoustic impedance layer having a relatively high acoustic impedance and at least one low acoustic impedance layer having a relatively low acoustic impedance are aligned in the thickness direction D 1  of the support substrate  11 . In the above-described laminated structure, a plurality of high acoustic impedance layers may be provided, or a plurality of low acoustic impedance layers may be provided. In this case, the laminated structure includes a plurality of high acoustic impedance layers and a plurality of low acoustic impedance layers that are alternately aligned, one by one, in the thickness direction D 1  of the support substrate  11 . 
     The high acoustic impedance layer is preferably made of, for example, platinum, tungsten, aluminum nitride, lithium tantalate, sapphire, lithium niobate, silicon nitride or zinc oxide. 
     The low acoustic impedance layer is preferably made of, for example, silicon oxide, aluminum or titanium. 
     Although a single IDT electrode  13  is provided on the piezoelectric film  122  in the elastic wave devices  1 ,  1   a ,  1   b,    1   c  and  1   d,  the number of IDT electrodes  13  is not limited to one, and a plurality of IDT electrodes  13  may be provided. In the case in which the elastic wave devices  1 ,  1   a,    1   b,    1   c  and  1   d  each include a plurality of IDT electrodes  13 , for example, a plurality of surface acoustic wave resonators including the respective plurality of IDT electrodes  13  may be electrically connected to each other to define a band pass filter, for example. 
     Further, the material of the insulation layer  16  and the spacer layers  17  and  17   b  in the elastic wave devices  1 ,  1   b,    1   c  and  1   d  is not limited to an organic material, such as synthetic resin, and may be an inorganic material. 
     In the electronic component module  100   b,  it is sufficient that a difference in coefficient of linear expansion between the cover  18   b  and the support substrate  11  is smaller than a difference in coefficient of linear expansion between the mounting substrate  2  and the support substrate  11 , and the cover  18   b  is not limited to a silicon substrate, and may be, for example, a borosilicate glass substrate or other suitable substrate. 
     The following advantageous effects are disclosed based on the above-described preferred embodiments. 
     An electronic component module ( 100 ,  100   a,    100   b,    100   c  and  100   d ) according to a preferred embodiment of the present invention includes the elastic wave device ( 1 ,  1   a,    1   b,    1   c  or  1   d ) and the mounting substrate ( 2 ). Each of the elastic wave devices ( 1 ,  1   a,    1   b,    1   c  and  1   d ) is mounted on the mounting substrate ( 2 ). Each of the elastic wave devices ( 1 ,  1   a,    1   b,    1   c  and  1   d ) includes the support substrate ( 11 ), the piezoelectric film ( 122 ), the IDT electrode ( 13 ), the insulation layer ( 16 ), the wiring electrode ( 15  or  15   b ), and the external connection electrode ( 142 ,  142   a  or  142   b ). The support substrate ( 11 ) is a crystal substrate. The piezoelectric film ( 122 ) is provided directly or indirectly on the support substrate ( 11 ). The IDT electrode ( 13 ) is provided on the piezoelectric film ( 122 ). The insulation layer ( 16 ) is provided on the support substrate ( 11 ). At least a portion of each of the wiring electrodes ( 15  and  15   b ) is provided on the insulation layer ( 16 ). Each of the wiring electrodes ( 15  and  15   b ) is electrically connected to the IDT electrode ( 13 ). Each of the external connection electrodes ( 142 ,  142   a  and  142   b ) is electrically connected to the wiring electrode ( 15 ). Each of the external connection electrodes ( 142 ,  142   a  and  142   b ) and the piezoelectric film ( 122 ) do not overlap each other in a plan view in the thickness direction (D 1 ) of the support substrate ( 11 ). Each of the elastic wave devices ( 1 ,  1   a,    1   b,    1   c  and  1   d ) is mounted on the mounting substrate ( 2 ) via the external connection electrode ( 142 ,  142   a  or  142   b ). The mounting substrate ( 2 ) has a coefficient of linear expansion different from that of the support substrate ( 11 ). A surface on the piezoelectric film ( 122 ) side (the first main surface  111 ) of the support substrate ( 11 ) is a {100} plane. 
     In the electronic component modules ( 100 ,  100   a,    100   b ,  100   c  and  100   d ), it is possible to reduce or prevent the occurrence of cracking, chipping or other damage in the piezoelectric film ( 122 ) and the occurrence of cracking in the support substrate ( 11 ). 
     An electronic component module ( 100 ,  100   a,    100   b,    100   c  and  100   d ) according to a preferred embodiment of the present invention includes the elastic wave device ( 1 ,  1   a,    1   b,    1   c  or  1   d ) and the mounting substrate ( 2 ). Each of the elastic wave devices ( 1 ,  1   a,    1   b,    1   c  and  1   d ) is mounted on the mounting substrate ( 2 ). The mounting substrate ( 2 ) is a printed wiring substrate or an LTCC substrate. Each of the elastic wave devices ( 1 ,  1   a,    1   b,    1   c  and  1   d ) includes the support substrate ( 11 ), the piezoelectric film ( 122 ), the IDT electrode ( 13 ), the insulation layer ( 16 ), the wiring electrode ( 15  or  15   b ), and the external connection electrode ( 142 ,  142   a  or  142   b ). The piezoelectric film ( 122 ) is provided directly or indirectly on the support substrate ( 11 ). The IDT electrode ( 13 ) is provided on the piezoelectric film ( 122 ). The insulation layer ( 16 ) is provided on the support substrate ( 11 ). At least a portion of each of the wiring electrodes ( 15  and  15   b ) is provided on the insulation layer ( 16 ). Each of the wiring electrodes ( 15  and  15   b ) is electrically connected to the IDT electrode ( 13 ). Each of the external connection electrodes ( 142 ,  142   a  and  142   b ) is electrically connected to the wiring electrode ( 15 ). Each of the external connection electrodes ( 142 ,  142   a  and  142   b ) and the piezoelectric film ( 122 ) do not overlap each other in a plan view in the thickness direction (D 1 ) of the support substrate ( 11 ). Each of the elastic wave devices ( 1 ,  1   a,    1   b,    1   c  and  1   d ) is mounted on the mounting substrate ( 2 ) via the external connection electrode ( 142 ,  142   a  or  142   b ). The support substrate ( 11 ) is a silicon substrate, a germanium substrate or a diamond substrate. A surface on the piezoelectric film ( 122 ) side (the first main surface  111 ) of the support substrate ( 11 ) is a {100} plane. 
     In the electronic component module ( 100 ,  100   a,    100   b ,  100   c  and  100   d ), it is possible to prevent the occurrence of cracking, chipping, or other damage in the piezoelectric film ( 122 ) and the occurrence of cracking in the support substrate ( 11 ). 
     An electronic component module ( 100 ,  100   a,    100   b,    100   c  and  100   d ) according to a preferred embodiment of the present invention is structured such that a difference between a coefficient of linear expansion of the insulation layer ( 16 ) and that of the support substrate ( 11 ) is larger than a difference between a coefficient of linear expansion of the piezoelectric film ( 122 ) and that of the support substrate ( 11 ). 
     An electronic component module ( 100 ) according to a preferred embodiment of the present invention further includes the spacer layer ( 17 ), the cover ( 18 ), and the penetration electrode ( 141 ). The spacer layer ( 17 ) is provided on the insulation layer ( 16 ). The cover ( 18 ) is provided on the spacer layer ( 17 ). The penetration electrode ( 141 ) is provided on the insulation layer ( 16 ) and the wiring electrode ( 15 ). The penetration electrode ( 141 ) is electrically connected to the wiring electrode ( 15 ). The penetration electrode ( 141 ) penetrates through the spacer layer ( 17 ) and the cover ( 18 ) in the thickness direction (D 1 ). The external connection electrode ( 142 ) is provided on the penetration electrode ( 141 ) and the cover ( 18 ). The external connection electrode ( 142 ) is electrically connected to the wiring electrode ( 15 ) and the penetration electrode ( 141 ). 
     An electronic component module ( 100   b ) according to a preferred embodiment of the present invention includes the spacer layer ( 17   b ), the cover ( 18   b ), and the penetration electrode ( 141   b ). At least a portion of the spacer layer ( 17   b ) is provided on the insulation layer ( 16 ). The spacer layer ( 17   b ) is provided in the outer side portion of the IDT electrode ( 13 ) in a plan view in the thickness direction (D 1 ) of the support substrate ( 11 ). The cover ( 18   b ) is provided on the spacer layer ( 17   b ). The penetration electrode ( 141   b ) is electrically connected to the wiring electrode ( 15   b ). The penetration electrode ( 141   b ) penetrates through the insulation layer ( 16 ) and the support substrate ( 11 ). The external connection electrode ( 142   b ) is electrically connected to the penetration electrode ( 141   b ). The external connection electrode ( 142   b ) overlaps with the penetration electrode ( 141   b ) in a plan view in the thickness direction (D 1 ) of the support substrate ( 11 ). The external connection electrode ( 142   b ) is provided on a side of the surface (second main surface  112 ) of the support substrate ( 11 ) on the opposite side to the surface (first main surface  111 ) on the piezoelectric film ( 122 ) side of the support substrate ( 11 ). 
     In an electronic component module ( 100   b ) according to a preferred embodiment of the present invention, since the penetration electrode ( 141   b ) penetrates through the support substrate ( 11 ), it is possible to improve the heat dissipation property as compared with a case in which the penetration electrode penetrates through the spacer layer made of resin and the cover made of resin. 
     An electronic component module ( 100 ,  100   a,    100   b,    100   c  and  100   d ) according to a preferred embodiment of the present invention is structured such that a difference in coefficient of linear expansion between the cover ( 18  or  18   b ) and the support substrate ( 11 ) is smaller than a difference in coefficient of linear expansion between the mounting substrate ( 2 ) and the support substrate ( 11 ). 
     In the electronic component module ( 100 ,  100   a,    100   b ,  100   c  and  100   d ), it is possible to reduce or prevent the occurrence of cracking in the support substrate ( 11 ). 
     An electronic component module ( 100 ,  100   a,    100   b,    100   c  and  100   d ) according to a preferred embodiment of the present invention is structured such that the cover ( 18  or  18   b ) is made of silicon. 
     In the electronic component module ( 100 ,  100   a,    100   b ,  100   c  and  100   d ), the difference in coefficient of linear expansion between the cover ( 18  or  18   b ) and the support substrate ( 11 ) is able to be made smaller. 
     An electronic component module ( 100 ,  100   a,    100   b,    100   c  and  100   d ) according to a preferred embodiment of the present invention is structured such that a surface of the cover ( 18  or  18   b ) on the opposite side to the surface on the support substrate ( 11 ) side thereof is a {100} plane. 
     In the electronic component modules ( 100 ,  100   a,    100   b ,  100   c  and  100   d ) according to preferred embodiments of the present invention, it is possible to prevent the occurrence of chipping in the cover ( 18  or  18   b ) in comparison with a case in which the surface of the cover ( 18   b ) is a (111) plane in the cutting process with a dicing machine at the time of manufacturing, for example. 
     An electronic component module ( 100 ,  100   a,    100   b,    100   c  and  100   d ) according to a preferred embodiment of the present invention is structured such that the mounting substrate ( 2 ) is a printed wiring substrate. 
     In the electronic component module ( 100 ,  100   a,    100   b ,  100   c  and  100   d ), there is an advantage that an inductor is able to be easily provided in the mounting substrate ( 2 ), for example, as compared with a case in which the mounting substrate ( 2 ) is an LTCC substrate. 
     An electronic component module ( 100 ,  100   a,    100   b,    100   c  and  100   d ) according to a preferred embodiment of the present invention is structured such that the external connection electrode ( 142 ,  142   a  or  142   b ) is a bump. The material of the bump is solder or gold, for example. 
     An electronic component module ( 100 ,  100   a  and  100   b ) according to preferred embodiments of the present invention is structured such that the elastic wave device ( 1 ,  1   a  or  1   b ) further includes the low acoustic velocity film ( 121 ). The low acoustic velocity film ( 121 ) is provided on the support substrate ( 11 ), and the acoustic velocity of the bulk waves propagating in the low acoustic velocity film ( 121 ) is lower than the acoustic velocity of the elastic waves propagating in the piezoelectric film ( 122 ). The support substrate ( 11 ) defines a high acoustic velocity support substrate in which the bulk waves propagate at an acoustic velocity higher than that of the elastic waves propagating in the piezoelectric film ( 122 ). 
     In the electronic component module ( 100 ,  100   a  and  100   b ) according to preferred embodiments of the present invention, it is possible to reduce the loss and increase the Q value in the elastic wave device ( 1 ,  1   a  or  1   b ) as compared with a case in which the low acoustic velocity film ( 121 ) is not provided. 
     An electronic component module ( 100   c ) according to a preferred embodiment of the present invention is configured such that the elastic wave device ( 1   c ) further includes the high acoustic velocity film ( 120 ) and the low acoustic velocity film ( 121 ). The high acoustic velocity film ( 120 ) is provided on the support substrate ( 11 ), and the acoustic velocity of the bulk waves propagating in the high acoustic velocity film ( 120 ) is higher than the acoustic velocity of the elastic waves propagating in the piezoelectric film ( 122 ). The low acoustic velocity film ( 121 ) is provided on the high acoustic velocity film ( 120 ), and the acoustic velocity of the bulk waves propagating in the low acoustic velocity film ( 121 ) is lower than the acoustic velocity of the elastic waves propagating in the piezoelectric film ( 122 ). 
     In the electronic component module ( 100   c ), it is possible to prevent the leakage of elastic waves into the support substrate ( 11 ). 
     An electronic component module ( 100 ,  100   a,    100   b,    100   c  and  100   d ) according to a preferred embodiment of the present invention is structured such that the material of the support substrate ( 11 ) is silicon, germanium or diamond. 
     An electronic component module ( 100 ,  100   a,    100   b,    100   c  and  100   d ) according to a preferred embodiment of the present invention is structured such that the material of the piezoelectric film ( 122 ) is lithium tantalate, lithium niobate, zinc oxide, aluminum nitride or PZT. 
     An electronic component module ( 100 ,  100   a  and  100   b ) according to a preferred embodiment of the present invention is structured such that the material of the low acoustic velocity film ( 121 ) is at least one kind of material selected from the group including silicon oxide, glass, silicon oxynitride, tantalum oxide, and a compound in which fluorine, carbon, or boron is added to silicon oxide. 
     An electronic component module ( 100   c ) according to a preferred embodiment of the present invention is structured such that the material of the high acoustic velocity film ( 120 ) is at least one kind of material selected from the group including diamond-like carbon, aluminum nitride, aluminum oxide, silicon carbide, silicon nitride, silicon, sapphire, lithium tantalate, lithium niobate, quartz, alumina, zirconia, cordierite, mullite, steatite, forsterite and magnesia diamond. 
     While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.