JP6432558B2 - Elastic wave device - Google Patents

Description

  The present invention relates to an acoustic wave device in which a laminated film and a piezoelectric thin film are laminated on a support substrate.

  In the elastic wave device described in Patent Document 1 below, a laminated film is provided on a support substrate, and a piezoelectric thin film is laminated on the laminated film. The laminated film has a high sound velocity film and a low sound velocity film. The low sound velocity film is a film in which the sound velocity of the propagating bulk wave is lower than that of the bulk wave propagating through the piezoelectric thin film. The high sound velocity film is made of a film in which the sound velocity of the propagating bulk wave is higher than the sound velocity of the elastic wave propagating through the piezoelectric thin film. A low sonic film is laminated on the high sonic film. An IDT electrode is provided on the piezoelectric thin film.

WO2012 / 086639A1

In the elastic wave device described in Patent Document 1, the piezoelectric thin film is made of a piezoelectric single crystal such as LiTaO ₃ . Therefore, in the dicing process for obtaining individual acoustic wave devices, if the laminated body having the piezoelectric thin film and the laminated film is cut, the piezoelectric thin film may be cracked or chipped.

  On the other hand, when the support layer and the cover member are provided in order to provide the hollow space where the IDT electrode faces, the sealing performance of the hollow space may not be sufficiently improved. For this reason, sufficient reliability may not be obtained.

  An object of the present invention is to provide an elastic wave device that is unlikely to cause cracking or chipping of a piezoelectric thin film and that can effectively improve reliability.

  An elastic wave device according to the present invention is provided on a support substrate, the support substrate, a laminated film including a piezoelectric thin film and a layer other than the piezoelectric thin film, and an IDT provided on one surface of the piezoelectric thin film. An electrode, an external connection terminal electrically connected to the IDT electrode and electrically connected to the outside, and in a region outside the region where the IDT electrode is provided in a plan view. And in the region below the portion where the external connection terminal is joined, the laminated film is partially removed, and an insulating layer provided in at least a part of the region where the laminated film is removed, The external connection terminal includes at least one of an under bump metal layer and a metal bump, is provided on the insulating layer so as to surround a region where the IDT electrode is provided, and the insulation layer Further comprising a support layer mainly composed of the same material, and a cover member fixed to said support layer so as to seal the opening formed by the supporting layer.

  On the specific situation with the elastic wave apparatus which concerns on this invention, the said insulating layer is provided so that it may reach on the said piezoelectric thin film from at least one part of the area | region from which the said laminated film was removed. In this case, interfacial peeling in the laminated film and peeling between the laminated film and the piezoelectric thin film hardly occur.

  In another specific aspect of the acoustic wave device according to the present invention, the elastic wave device is electrically connected to the IDT electrode, reaches the insulating layer from the piezoelectric thin film, and is located in a region where the laminated film is removed. Wiring electrodes are further provided that extend over the insulating layer portion. In this case, the external connection terminal can be joined to the wiring electrode in the region where the laminated film is removed. Therefore, even if a force is applied when joining the external connection terminals, the piezoelectric thin film is not easily cracked or chipped.

  In another specific aspect of the acoustic wave device according to the present invention, the external connection terminal is joined to the wiring electrode.

  On the specific situation with the elastic wave apparatus which concerns on this invention, the said insulating layer and the said support layer consist of synthetic resins. In this case, the bonding strength between the insulating layer and the support layer is increased. Furthermore, the airtightness of the hollow space formed by the support substrate, the support layer, and the cover member can be suitably enhanced. Therefore, the reliability can be effectively increased.

  In another specific aspect of the acoustic wave device according to the present invention, the insulating layer reaches from the piezoelectric thin film to a side surface of the piezoelectric thin film and the laminated film, and reaches at least a part of a region where the laminated film is removed. Yes. In this case, interfacial peeling in the laminated film and peeling between the laminated film and the piezoelectric thin film are less likely to occur.

  In still another specific aspect of the acoustic wave device according to the present invention, a surface of the insulating layer opposite to the supporting substrate is formed from a region where the insulating layer is located on the supporting substrate. A portion having an inclined surface that is inclined so as to approach the piezoelectric thin film side as it moves away from the support substrate over a portion located above, and the wiring electrode is located on the inclined surface of the insulating layer The portion is inclined along the inclined surface of the insulating layer. In this case, disconnection of the wiring electrode is difficult to occur.

  In another specific aspect of the acoustic wave device according to the present invention, the insulating layer reaches a region where the laminated film and the piezoelectric thin film are removed from the inclined surface of the insulating layer. In this case, disconnection of the wiring electrode is difficult to occur.

  In still another specific aspect of the acoustic wave device according to the present invention, the inclined surface of the insulating layer is in a region on the support substrate from which the stacked film is removed and the insulating layer is not stacked. The wiring electrode reaches a region on the support substrate where the laminated film is removed and the insulating layer is not laminated. In this case, the wiring electrode is hardly peeled off and the wiring electrode is not easily broken.

  In still another specific aspect of the elastic wave device according to the present invention, the laminated film is a high-sonic film in which the bulk wave propagating at a higher speed than the acoustic wave in the main mode propagating through the piezoelectric thin film is higher in speed. As a layer other than the piezoelectric thin film, the piezoelectric thin film is laminated on the high sound velocity film.

  In still another specific aspect of the elastic wave device according to the present invention, the laminated film has a high sound velocity film in which a sound velocity of a bulk wave propagating faster than a sound velocity of a main mode elastic wave propagating through the piezoelectric thin film A layer other than the piezoelectric thin film is laminated on the high sound velocity film and has a low sound velocity film whose bulk wave velocity is lower than that of the main mode elastic wave propagating through the piezoelectric thin film. The piezoelectric thin film is laminated on the low sound velocity film.

  In still another specific aspect of the elastic wave device according to the present invention, the laminated film includes a high acoustic impedance film having a relatively high acoustic impedance, and a low acoustic impedance film having a low acoustic impedance compared to the high acoustic impedance film. Have

  According to the present invention, it is possible to provide an elastic wave device that is unlikely to be cracked or chipped in a piezoelectric thin film and that can effectively improve reliability.

FIG. 3 is a cross-sectional view of the acoustic wave device according to the first embodiment of the present invention, corresponding to a portion along line II in FIG. 2. It is a schematic plan view which omits and shows the cover member of the elastic wave device concerning a 1st embodiment of the present invention. It is a partial notch expanded sectional view of the elastic wave apparatus corresponded in the part which follows the II-II line in FIG. It is sectional drawing of the elastic wave apparatus which concerns on the 1st modification of the 1st Embodiment of this invention corresponding to the part in alignment with the II line | wire in FIG. (A) is a partial notch expanded sectional view for demonstrating the principal part of the elastic wave apparatus of the 1st Embodiment of this invention, (b) further expanded the principal part in (a). It is a partial notch sectional view shown. It is a partial notch expanded sectional view of the elastic wave apparatus of the 2nd modification of 1st Embodiment corresponding to the part which follows the II-II line in FIG. (A) is a partial notch expansion sectional view for demonstrating the principal part of the elastic wave apparatus of the 2nd Embodiment of this invention, (b) expands further the principal part in (a). It is a partial notch sectional view shown. It is sectional drawing of the elastic wave apparatus concerning 3rd Embodiment corresponded to the part in alignment with the II line | wire in FIG. It is front sectional drawing of the laminated film in the 4th Embodiment of this invention.

  Hereinafter, the present invention will be clarified by describing specific embodiments of the present invention with reference to the drawings.

  It should be pointed out that each embodiment described in this specification is an exemplification, and a partial replacement or combination of configurations is possible between different embodiments.

  FIG. 1 is a cross-sectional view of an acoustic wave device according to a first embodiment of the present invention, corresponding to a portion along line II in FIG. 2 described later.

  The acoustic wave device 1 has a support substrate 2. The support substrate 2 has first and second main surfaces 2a and 2b facing each other. A laminated film 3 is provided on the first main surface 2a. The laminated film 3 includes a high acoustic velocity film 3a, a low acoustic velocity film 3b laminated on the high acoustic velocity film 3a, and a piezoelectric thin film 4 laminated on the low acoustic velocity film 3b. In the laminated film 3, the piezoelectric thin film 4 is located at the top. The high sound velocity film 3 a is a film in which the sound velocity of the propagating bulk wave is higher than the sound velocity of the main mode elastic wave propagating through the piezoelectric thin film 4. The low sound velocity film 3 b is a film in which the sound velocity of the propagating bulk wave is lower than the sound velocity of the main mode elastic wave propagating through the piezoelectric thin film 4.

  Note that the sound speed of the bulk wave is a sound speed inherent to the material, and there are a P wave that vibrates in the wave traveling direction, that is, the longitudinal direction, and an S wave that vibrates in the lateral direction that is perpendicular to the traveling direction. The bulk wave propagates in any of the piezoelectric film, the high sound speed film, and the low sound speed film. In the case of isotropic materials, there are P waves and S waves. In the case of anisotropic materials, there are P waves, slow S waves, and fast S waves. When the surface acoustic wave is excited using an anisotropic material, an SH wave and an SV wave are generated as two S waves. In this specification, the acoustic velocity of the elastic wave of the main mode propagating through the piezoelectric thin film obtains the pass band as a filter and the resonance characteristics as a resonator among the three modes of P wave, SH wave and SV wave. Say the mode you are using for.

  An adhesion layer may be formed between the low acoustic velocity film 3b and the piezoelectric thin film 4. When the adhesion layer is formed, the adhesion between the low acoustic velocity film 3b and the piezoelectric thin film 4 can be improved. The adhesion layer may be a resin or metal, and for example, an epoxy resin or a polyimide resin is used.

The piezoelectric thin film 4 is made of LiTaO _{3 in} this embodiment. However, other piezoelectric single crystals may be used. The film thickness of the piezoelectric thin film 4 is preferably 1.5λ or less, where λ is the wavelength of the elastic wave determined by the electrode period of the IDT electrode. In this case, the electromechanical coupling coefficient can be easily adjusted by selecting the film thickness of the piezoelectric thin film 4 within a range of 1.5λ or less.

  The high sonic velocity film 3a is made of an appropriate material that satisfies the above sonic velocity relationship. Examples of such materials include aluminum nitride, aluminum oxide, silicon carbide, silicon nitride, silicon oxynitride, DLC, diamond, and the like. Moreover, you may use the mixed material which has these materials as a main component.

  The low acoustic velocity film 3 b is made of an appropriate material whose bulk acoustic velocity is lower than the acoustic velocity of the main mode elastic wave propagating through the piezoelectric thin film 4. Examples of such a material include silicon oxide, glass, silicon oxynitride, tantalum oxide, and a compound obtained by adding fluorine, carbon, boron, or the like to silicon oxide. The low acoustic velocity film 3b may also be made of a mixed material mainly composed of these materials.

  Since the high sound velocity film 3 a and the low sound velocity film 3 b are laminated on the piezoelectric thin film 4, the Q value can be increased as described in Patent Document 1.

  A plurality of high sound velocity films and a plurality of low sound velocity films may be laminated in the laminated film 3. Furthermore, the laminated film 3 is composed of a film other than the piezoelectric thin film 4, the high acoustic velocity film 3 a, and the low acoustic velocity film 3 b, for example, the adhesion layer, the dielectric film, etc. You may have in.

  Incidentally, IDT electrodes 5 a to 5 c are provided on the piezoelectric thin film 4. IDT electrodes 5a-5c are electrically connected by wiring electrodes 6a-6d.

  In the present embodiment, surface acoustic wave resonators composed of a plurality of IDT electrodes 5a to 5c are connected to each other. Thereby, a band-pass filter is configured. The filter circuit is not particularly limited.

  A hollow space 7 is provided in order not to restrain the elastic wave excited by the IDT electrodes 5a to 5c. That is, a support layer 8 having an opening is provided on the support substrate 2. The support layer 8 is made of a synthetic resin such as polyimide.

  A cover member 9 is provided so as to seal the opening of the support layer 8. The hollow space 7 is sealed by the cover member 9 and the support layer 8.

  On the other hand, a through hole is formed so as to penetrate the support layer 8 and the cover member 9. Under bump metal layers 10a and 10b are provided in the through holes. Metal bumps 11a and 11b are joined to the under bump metal layers 10a and 10b. The under bump metal layers 10a and 10b and the metal bumps 11a and 11b constitute external connection terminals in the present invention. The external connection terminal is a portion that is electrically connected to the IDT electrode and electrically connects the acoustic wave device to the outside. The external connection terminal only needs to have at least one of the under bump metal layer and the metal bump.

  The under bump metal layers 10a and 10b and the metal bumps 11a and 11b are made of an appropriate metal or alloy.

  The lower end of the under bump metal layer 10a is joined to the wiring electrode 6a. The lower end of the under bump metal layer 10b is joined to the wiring electrode 6d. Therefore, the portions where the under bump metal layers 10a and 10b of the wiring electrodes 6a and 6d are joined become electrode lands to which the external connection terminals are connected. In the present embodiment, under bump metal layers 10a and 10b and metal bumps 11a and 11b are provided as external connection terminals.

  On the other hand, an insulating layer 12 is provided on the support substrate 2. The support layer 8 is directly provided on the insulating layer 12.

  By the way, the feature of the elastic wave device 1 of the present embodiment is that the support layer 8 and the insulating layer 12 are made of the same material. Thereby, the bonding force between the support layer 8 and the insulating layer 12 is high. Therefore, the airtightness of the hollow space 7 can be effectively enhanced. In addition, the linear expansion coefficients of the support layer 8 and the insulating layer 12 are the same. Thereby, when a thermal shock is applied, stress is hardly generated at the interface between the support layer 8 and the insulating layer 12. Therefore, the reliability can be effectively increased.

  In the present embodiment, the support layer 8 and the insulating layer 12 are made of the same material and are integrated. Therefore, the above effect can be further enhanced. Note that the support layer and the insulating layer are not necessarily integrated. Even in this case, the above effects can be obtained.

  Since the material of the support layer 8 and the insulating layer 12 is the same, the kind of material used can also be reduced. Alternatively, the cost can be reduced. Note that the material of the support layer and the material of the insulating layer may be substantially the same, and may not be completely the same.

  Note that the material of the support layer 8 and the insulating layer 12 being the same means a material in which the main component of the material of the support layer 8 and the insulating layer 12 is 50% or more. Moreover, it is more preferable if the main components of the material of the support layer 8 and the insulating layer 12 are 75% or more the same. Moreover, it is more preferable if the main components of the material of the support layer 8 and the insulating layer 12 are 90% or more the same. Furthermore, it is more preferable that the main components of the material of the support layer 8 and the insulating layer 12 are 100% the same. In particular, when the support layer 8 and the insulating layer 12 are synthetic resins such as polyimide, the bonding force between the support layer 8 and the insulating layer 12 is further increased.

  In addition, that the linear expansion coefficient of the support layer 8 and the insulating layer 12 is the same means that the difference of the linear expansion coefficient between the support layer 8 and the insulating layer 12 is within 50%. Further, it is more preferable that the difference in coefficient of linear expansion between the support layer 8 and the insulating layer 12 is within 30%. Furthermore, it is more preferable that the difference in linear expansion coefficient between the support layer 8 and the insulating layer 12 is within 10%.

  FIG. 2 is a schematic plan view of the acoustic wave device 1. Here, the above-described cover member 9 is seen through, and the lower electrode structure is schematically shown. The IDT electrodes 5a to 5c are shown by a rectangular schematic view of the area where the IDT electrodes 5a to 5c are provided. FIG. 3 is a partially cutaway enlarged cross-sectional view of the acoustic wave device corresponding to a portion along the line II-II in FIG. 2. 1 is a cross-sectional view of the acoustic wave device taken along line II in FIG.

  As shown in FIG. 3, the bonding area between the support layer 8 and the insulating layer 12 is large in a portion where the wiring electrode 6 a is not provided. In addition, as shown in FIG. 1, in the present embodiment, the wiring electrodes 6 a and 6 d do not reach the outer peripheral portion 8 a of the support layer 8. Therefore, the support layer 8 is joined to the insulating layer 12 over the entire circumference of the outer peripheral portion 8a. Therefore, the sealing property of the hollow space 7 can be effectively increased, and the reliability of the acoustic wave device 1 can be effectively increased.

  Note that the wiring electrodes 46 a and 46 d may reach the outer peripheral portion 8 a of the support layer 8 as in the elastic wave device 41 of the first modification shown in FIG. 4. The support layer 8 is bonded to the insulating layer 12 in a portion where the wiring electrodes 46a and 46d are not provided. In the first modification, the support layer 8 and the insulating layer 12 are not integrated. Even in this case, the airtightness of the hollow space 7 can be improved.

  Returning to FIG. 1, the structure in which the laminated film 3 is laminated is partially removed on the support substrate 2. That is, in the first main surface 2a of the support substrate 2, a region R in which the structure in which the laminated film 3 is laminated is partially removed is provided outside the region in which the laminated film 3 is provided. Yes. Here, the region where the laminated film 3 is partially removed is a portion outside the region where the IDT electrodes 5a to 5c are provided, and the portion where the external connection terminal is joined. At least the region below.

  In the present embodiment, the region where the external connection terminal is bonded is a portion bonded to the wiring electrode 6a at the lower end of the under bump metal layer 10a. That is, the lower end surface of the under bump metal layer 10a becomes the joined portion, and a region obtained by projecting the joined portion onto the first main surface 2a of the support substrate 2 is the joined portion. This is the lower area.

  As in the present embodiment, it is preferable that the wiring electrodes 6a and 6d reach the region R. Thereby, in the region R, the under bump metal layers 10a and 10b and the metal bumps 11a and 11b can be bonded onto the wiring electrodes 6a and 6d. Therefore, even if a force is applied when the metal bumps 11a and 11b are joined to the under bump metal layers 10a and 10b, the piezoelectric thin film 4 is not easily chipped or cracked.

  Further, in the dicing process for dividing into individual elastic wave devices 1, dicing is preferably performed in the region R. Thereby, chipping and cracking of the piezoelectric thin film 4 are difficult to occur.

  The insulating layer 12 preferably extends from the region R through the side surface 3d of the laminated film 3 to the upper surface of the piezoelectric thin film 4. Here, in the present embodiment, the surface opposite to the first main surface 2 a of the insulating layer 12 has an inclined surface 12 a in a portion from the region R to the piezoelectric thin film 4. The wiring electrode 6a also has an inclined surface 6a1 along the inclined surface 12a. Therefore, in the wiring electrode 6a, the bending degree of the wiring electrode 6a between the region where the multilayer film 3 is stacked and the region R is relaxed. Therefore, disconnection hardly occurs in the portion indicated by the arrow S1 of the wiring electrode 6a. Similarly, on the wiring electrode 6d side, the degree of bending of the portion indicated by the arrow S2 is reduced. Therefore, disconnection of the wiring electrode 6d is difficult to occur.

  This will be described in more detail with reference to FIGS. 5 (a) and 5 (b).

  FIG. 5A is an enlarged partial cutaway sectional view showing the vicinity of a portion where the region R and the laminated film 3 are in contact with each other.

  As shown in FIG. 5A, the insulating layer 12 extends from the portion located in the region R onto the piezoelectric thin film 4. In this case, as shown in an enlarged view in FIG. 5B, the inclined surface 12 a of the insulating layer 12 is located above the side surface 3 d of the laminated film 3. The inclined surface 12 a is provided so as to extend from above the region R to above the piezoelectric thin film 4. An angle C1 formed by the inclined surface 12a and the first main surface 2a of the support substrate 2 is preferably 80 ° or less. Thereby, as described above, the angle formed between the inclined surface 6a1 of the wiring electrode 6a and the first main surface 2a is also reduced. Thereby, the degree of bending at the portion where the inclined surface 6a1 of the wiring electrode 6a is provided can be reduced. In other words, the influence of the step between the first main surface 2 a of the support substrate 2 and the upper surface of the piezoelectric thin film 4 in the region R outside the side surface 3 d of the laminated film 3 can be reduced by the insulating layer 12. Has been. Therefore, disconnection hardly occurs in the portion indicated by the arrow S1 of the wiring electrode 6a.

  Preferably, the inclined surface 12b is also provided at the inner end 12c of the insulating layer 12. An angle C2 formed by the inclined surface 12b with the first main surface 2a is also preferably 80 ° or less. As a result, disconnection of the wiring electrode 6a above the inclined surface 12b hardly occurs.

  The angle C1 formed by the inclined surface 12a and the first main surface 2a and the angle C2 formed by the inclined surface 12b and the first main surface 2a are more preferably 60 ° or less. Further, the angle C1 formed by the inclined surface 12a and the first main surface 2a and the angle C2 formed by the inclined surface 12b and the first main surface 2a are more preferably 45 ° or less.

  As described above, in the wiring electrode 6a, by reducing the degree of bending, disconnection when heat is applied and disconnection in the process of forming the wiring electrode 6a are less likely to occur.

  Further, the side surface 3 d of the laminated film 3 is covered with the insulating layer 12. Therefore, interface peeling in the laminated film 3 hardly occurs.

  FIG. 6 is a partially cutaway enlarged cross-sectional view of an elastic wave device according to a second modification, corresponding to a portion along line II-II in FIG. Thus, the insulating layer 52 may have the inclined surface 52a outside the support layer 8. Even in this case, the bonding force between the support layer 8 and the insulating layer 52 is high as in the first embodiment. Therefore, the reliability can be effectively increased.

  FIG. 7A is a partially cutaway enlarged cross-sectional view showing the main part of an elastic wave device according to the second embodiment of the present invention, and FIG. 7B is a partially cutout showing the main part further enlarged. It is sectional drawing. FIGS. 7A and 7B are cross-sectional views of a portion corresponding to FIGS. 5A and 5B for the first embodiment.

  In the elastic wave device of the second embodiment, the insulating layer 22 is provided so as to extend from the region R on the first main surface 2 a of the support substrate 2 to the piezoelectric thin film 4. However, the insulating layer 12 in the acoustic wave device 1 of the first embodiment is extended outward on the region R. On the other hand, in the second embodiment, the insulating layer 22 has one end of the inclined surface 22 a in contact with the first main surface 2 a of the support substrate 2. That is, the insulating layer 22 does not reach the outside of the inclined surface 22a. On the other hand, on the piezoelectric thin film 4, an inclined surface 22b reaching the upper surface of the piezoelectric thin film 4 is provided as in the first embodiment.

  As shown in FIG. 7B, the angle C1 formed between the inclined surface 22a and the first main surface 2a and the angle C2 formed between the inclined surface 22b and the first main surface 2a are the same as those in the first embodiment. It is desirable that it is 80 degrees or less similarly to.

  The angle C1 formed between the inclined surface 22a and the first main surface 2a and the angle C2 formed between the inclined surface 22b and the first main surface 2a are more preferably 60 ° or less. Further, the angle C1 formed between the inclined surface 22a and the first main surface 2a and the angle C2 formed between the inclined surface 22b and the first main surface 2a are more preferably 45 ° or less.

  As described above, the insulating layer 22 may end at the inclined surface 22a toward the region R side from the portion located above the piezoelectric thin film 4. Even in this case, in the region R, as in the first embodiment, by joining the under bump metal layer and the metal bump onto the wiring electrode 26a, the piezoelectric thin film 4 is not easily chipped or cracked. Moreover, since the wiring electrode 26a also has the inclined surface 26a1, the disconnection of the wiring electrode 26a hardly occurs.

  In addition, the adhesion between the wiring electrode 26a and the support substrate 2 is high. Thereby, the wiring electrode 26a is difficult to peel off.

  Further, in the elastic wave device, the support layer 8 and the insulating layer 22 are joined in the same manner as the elastic wave device 1 of the first embodiment except for the portion where the wiring electrode 26a is provided. Therefore, the airtightness of the hollow space 7 can be improved. Therefore, the reliability of the acoustic wave device can be increased.

  FIG. 8 is a cross-sectional view of the acoustic wave device according to the third embodiment, corresponding to a portion along line II in FIG.

  The elastic wave device 61 is different from the first embodiment in that the laminated film 63 does not have a low acoustic velocity film. Except for the above, the elastic wave device 61 has the same configuration as the elastic wave device 1 of the first embodiment.

  Even in this case, similarly to the first embodiment, the piezoelectric thin film is hardly cracked or chipped, and the reliability can be effectively enhanced. The Q value can also be increased.

  FIG. 9 is a front sectional view of a laminated film in the fourth embodiment of the present invention. The fourth embodiment has the same configuration as that of the first embodiment except for the configuration of the laminated film 33.

  In the fourth embodiment, the laminated film 33 has a structure in which a low acoustic impedance film 33b having a relatively low acoustic impedance is laminated on a high acoustic impedance film 33a having a relatively high acoustic impedance. The piezoelectric thin film 4 is laminated on the low acoustic impedance film 33b. As described above, the laminated film is not limited to the above-described high sound velocity film and low sound velocity film, and may have a structure in which the high acoustic impedance film and the low acoustic impedance film are laminated.

  In the present invention, the configuration of the laminated film including the piezoelectric thin film is not particularly limited.

  Therefore, a laminated film may be formed by laminating a plurality of dielectric films for improving temperature characteristics.

DESCRIPTION OF SYMBOLS 1 ... Elastic wave apparatus 2 ... Support substrate 2a, 2b ... 1st, 2nd main surface 3 ... Laminated film 3a ... High-velocity film 3b ... Low-sonic film 3d ... Side surface 4 ... Piezoelectric thin films 5a-5c ... IDT electrode 6a- 6d ... wiring electrode 6a1 ... inclined surface 7 ... hollow space 8 ... support layer 8a ... outer periphery 9 ... cover members 10a, 10b ... under bump metal layers 11a, 11b ... metal bumps 12 ... insulating layers 12a, 12b ... inclined surfaces 12c ... Inner end 22 ... insulating layers 22a and 22b ... inclined surface 26a ... wiring electrode 26a1 ... inclined surface 33 ... laminated film 33a ... high acoustic impedance film 33b ... low acoustic impedance film 41 ... acoustic wave devices 46a and 46d ... wiring electrode 52 ... insulation Layer 52a ... inclined surface 61 ... elastic wave device 63 ... laminated film

Claims (12)

A support substrate;
A laminated film that is provided on the support substrate and includes a piezoelectric thin film and a layer other than the piezoelectric thin film;
An IDT electrode provided on one surface of the piezoelectric thin film;
An external connection terminal electrically connected to the IDT electrode and electrically connected to the outside;
In a plan view, the laminated film is partially removed in a region outside the region where the IDT electrode is provided and below the portion where the external connection terminal is joined. An insulating layer provided in at least a part of the region where the laminated film is removed;
With
The external connection terminal includes at least one of an under bump metal layer and a metal bump,
A support layer which is provided on the insulating layer so as to surround a region where the IDT electrode is provided, and which is made of the same material as the main component of the insulating layer;
A cover member fixed on the support layer so as to seal the opening formed by the support layer;
An elastic wave device further comprising:   The acoustic wave device according to claim 1, wherein the insulating layer is provided so as to reach the piezoelectric thin film from at least a part of a region where the laminated film is removed.   A wiring electrode that is electrically connected to the IDT electrode, extends from the piezoelectric thin film to the insulating layer, and reaches the insulating layer portion located in the region where the laminated film is removed; The elastic wave device according to claim 2 provided. The acoustic wave device according to claim 3, wherein the external connection terminal is joined to the wiring electrode.   The elastic wave device according to any one of claims 1 to 4, wherein the insulating layer and the support layer are made of a synthetic resin.   The said insulating layer reaches from the said piezoelectric thin film to the side surface of the said piezoelectric thin film and the said laminated film, and has reached at least one part of the area | region where the said laminated film was removed. Elastic wave device. As the surface of the insulating layer opposite to the supporting substrate moves away from the supporting substrate from a region where the insulating layer is positioned on the supporting substrate to a portion positioned on the piezoelectric thin film, the piezoelectric layer It has an inclined surface that is inclined so as to approach the thin film side,
The said wiring electrode has a part located on the said inclined surface of the said insulating layer, This part is inclined along the said inclined surface of the said insulating layer, The any one of Claims 3-6 The elastic wave device described in 1.   The acoustic wave device according to claim 7, wherein the insulating layer reaches a region where the laminated film and the piezoelectric thin film are removed from the inclined surface of the insulating layer. The inclined surface of the insulating layer reaches the region on the support substrate where the laminated film is removed and the insulating layer is not laminated,
The acoustic wave device according to claim 7, wherein the wiring electrode reaches an area on the support substrate where the laminated film is removed and the insulating layer is not laminated.   The laminated film has, as a layer other than the piezoelectric thin film, a high acoustic velocity film having a higher acoustic velocity of bulk waves propagating than the acoustic velocity of the main mode acoustic wave propagating through the piezoelectric thin film, and is on the high acoustic velocity film. The elastic wave device according to any one of claims 1 to 9, wherein the piezoelectric thin film is laminated.   The laminated film is laminated on the high sound velocity film having a higher acoustic velocity of the bulk wave propagating than the acoustic velocity of the main mode elastic wave propagating through the piezoelectric thin film, and the piezoelectric thin film A low-sonic film having a low acoustic velocity of the bulk wave propagating than the acoustic velocity of the propagating main mode elastic wave is formed as a layer other than the piezoelectric thin film, and the piezoelectric thin film is laminated on the low-sonic film. The elastic wave device according to any one of claims 1 to 9.   The said laminated film has a high acoustic impedance film | membrane with relatively high acoustic impedance, and a low acoustic impedance film | membrane with low acoustic impedance compared with a high acoustic impedance film | membrane of any one of Claims 1-9. Elastic wave device.

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