JP5117083B2 - Elastic wave device and manufacturing method thereof - Google Patents

Description

  The present invention relates to an acoustic wave device and a manufacturing method thereof, and more particularly to an acoustic wave device including a sealing portion having a cavity above an acoustic wave element and a manufacturing method thereof.

  The acoustic wave device is, for example, various circuits that process radio signals in a frequency band of 45 MHz to 2 GHz, such as a transmission bandpass filter, a reception bandpass filter, a local oscillation filter, an antenna duplexer, an intermediate frequency filter, an FM modulator, and the like. It is used for. In recent years, these signal processing devices have been miniaturized, and electronic components such as acoustic wave devices used are also required to be miniaturized. As an acoustic wave element used for an acoustic wave device, a surface acoustic wave (SAW) element in which a interdigital electrode (IDT) or a reflector is formed using a metal film on a piezoelectric substrate, or a piezoelectric thin film in which a piezoelectric thin film is sandwiched between metal electrodes. There is a resonator (FBAR) element.

  In particular, in portable electronic devices such as mobile telephone terminals, electronic parts are increasingly used as modules. Modularization is performed by surface mounting electronic components and sealing them with resin for cost reduction. Therefore, an acoustic wave device that can be surface-mounted and can withstand the pressure during modular resin sealing (for example, transfer molding) is required. At the same time, in order to maintain the characteristics of the acoustic wave element, it is required to provide a cavity on the upper surface of the functional part (vibration part) of the acoustic wave element. The functional part of the acoustic wave element is an IDT electrode finger in the surface acoustic wave element, and an area where the upper and lower electrodes sandwich the piezoelectric thin film in the piezoelectric thin film resonator element.

In order to satisfy such a requirement, a method of forming a structure (so-called hollow structure) provided with a sealing portion having a cavity in contact with a functional portion in an acoustic wave element has been proposed. Patent Document 1 discloses a method of forming a hollow structure by forming a dissolving resin in a region to be a cavity on an acoustic wave element, forming an upper plate on the dissolving resin, and then removing the dissolving resin. (Conventional example 1) is disclosed. In Patent Document 2, a frame structure surrounding the electrical structure element is formed, an auxiliary film is pasted on the frame structure so that the electrical structure element is hollow, and a resin layer is formed thereon. A method (conventional example 2) for forming a hollow structure by removing the frame structure other than the roof portion is disclosed. In Patent Document 3, a resin film is pasted on a piezoelectric substrate on which an acoustic wave element is formed, a resin film on an upper part of a functional part of the substrate on which a plurality of acoustic wave elements are provided is opened, and a circuit board is bonded onto the resin film. A method of forming a hollow structure (conventional example 3) is disclosed. In Patent Document 4, a photosensitive resin is formed on a substrate on which a plurality of acoustic wave elements are provided, the photosensitive resin at the upper part of the functional part of the acoustic wave element is opened, and the substrate of the wiring board assembly is mounted thereon. A method of forming a hollow structure by dividing by dicing (conventional example 4) is disclosed. Patent Document 5 discloses a method (conventional example 5) using different resins for the surrounding wall that surrounds the acoustic wave element and the lid for forming the hollow structure. Patent Document 6 discloses a method (Conventional Example 6) in which a metal cap is provided on an acoustic wave element and the metal cap is sealed with a resin.
Japanese Patent No. 3291406 Special table 2003-523082 gazette Japanese Patent No. 3196693 Japanese Patent No. 3225906 JP-A-10-93383 Japanese Patent Laid-Open No. 11-251855

  The elastic wave devices formed by the methods of Conventional Examples 1 to 4 cannot withstand the pressure applied during modularization, and the hollow structure is deformed. On the other hand, the method of Conventional Example 5 is intended to suppress the deformation of the hollow structure during modularization. However, for example, when a connection terminal for electrical connection to the outside is provided on the surface side of the acoustic wave device (side on which the surface acoustic wave element is formed) for surface mounting requirements, A through electrode is provided, and a connection terminal is provided on the through electrode. The lid is made of a material having a high elastic modulus to prevent deformation. For this reason, a crack etc. generate | occur | produce in a cover body, a penetration electrode, or a connection terminal by the thermal stress etc. of a penetration electrode, a connection terminal, and a cover body. In particular, stress concentrates between the connection terminal and the through electrode, and cracks and the like are likely to occur. On the other hand, when a metal cap is provided near the acoustic wave element as in the conventional example 6, the stray capacitance is increased. Further, in the conventional example 6, it is assumed that the metal caps are individually mounted on the acoustic wave element, and the manufacturing cost increases.

  The present invention has been made in view of the above problems, has a hollow structure that is not deformed by pressure, and suppresses the occurrence of cracks or the like due to thermal stress or the like in the through electrode or the resin sealing portion around it. Another object is to reduce the manufacturing cost of a hollow structure that is not deformed by pressure.

The present invention includes an acoustic wave element provided on a substrate, a resin sealing portion provided on the substrate so as to cover a side surface and an upper surface of the cavity having a cavity on the acoustic wave element, and other than the cavity A through-electrode that penetrates the resin-sealed portion and is electrically connected to the acoustic wave element, a connection terminal provided on the through-electrode, and a top and bottom sandwiched between the resin-sealed portions on the cavity And a reinforcing layer made of a metal having a larger elastic modulus than the resin sealing portion and electrically separated from the acoustic wave element . According to the present invention, since the top of the reinforcing layer is made of the resin sealing portion having a small elastic modulus, the stress can be relaxed. Furthermore, since a reinforcing layer having a higher elastic modulus than the resin sealing portion is provided on the cavity, a hollow structure that is not deformed by pressure can be provided. Furthermore, since the resin sealing portion is provided between the reinforcing layer and the cavity, stray capacitance can be suppressed.

  The said structure WHEREIN: The said reinforcement layer can be set as the structure completely enclosed by the said resin sealing part. According to this configuration, the step of electrically connecting the reinforcing layer to the acoustic wave device can be reduced.

The present invention includes a step of forming a reinforcing layer made of a metal having a larger elastic modulus than the first resin layer on the first resin layer, and a second resin layer having a smaller elastic modulus than the reinforcing layer so as to cover the reinforcing layer. Forming a resin sealing portion including the first resin layer and the second resin layer, and having a cavity on the acoustic wave element on a substrate provided with the acoustic wave element, the cavity A step of fixing the resin sealing portion such that the resin sealing portion covers the side surface and the upper surface of the substrate, the reinforcing layer is disposed on the cavity, and the reinforcing layer is electrically separated from the acoustic wave element. And a method of manufacturing an acoustic wave device. According to the present invention, it is not necessary to individually arrange the reinforcing layer on each acoustic wave element, and the manufacturing cost can be reduced.

  The said structure WHEREIN: It can be set as the structure which has the process of forming the penetration electrode which penetrates the said resin sealing part and is electrically connected with the said elastic wave element except the said cavity. According to this configuration, the stress caused by the through electrode is relaxed by the first resin layer, and the strength of the resin sealing portion on the cavity can be secured by the reinforcing layer.

  The said structure WHEREIN: It can be set as the structure which has the process of forming a connection terminal on the said penetration electrode. According to this configuration, the stress generated between the connection terminal and the through electrode can be relaxed by the first resin layer.

In the above configuration, the reinforcing layer may be formed using a plating method. According to these configurations, a reinforcing layer having a large elastic modulus can be easily formed.

  In the above configuration, the step of forming the resin sealing portion includes a step of forming a third resin layer having a recess to be the cavity on the second resin layer, and fixing the resin sealing portion May be a step of fixing the resin sealing portion to the substrate by fixing the third resin layer to the substrate. According to this configuration, the cavity can be easily formed by using the third resin layer.

  In the above configuration, the third resin layer is an adhesive resin, and the step of fixing the resin sealing portion is a step of bonding the resin sealing portion to the substrate using the third resin layer. It can be. According to this structure, a manufacturing process can be reduced by using the 3rd resin layer which has the recessed part used as a cavity as an adhesive agent.

  In the above configuration, the method includes a step of forming an adhesive layer so as to cover the third resin layer, and the step of fixing the resin sealing portion uses the adhesive layer and bonds the resin sealing portion to the substrate. It can be set as the structure which is a process to perform. According to this configuration, it is not necessary to use an adhesive resin as the third resin layer. Therefore, the room for material selection for the third resin layer and the adhesive layer can be expanded.

The present invention includes forming a reinforcing layer having a higher elastic modulus than the first resin layer on the first resin layer, and forming a second resin layer having a lower elastic modulus than the reinforcing layer so as to cover the reinforcing layer. A step of forming a resin sealing portion including the first resin layer and the second resin layer, a substrate provided with the acoustic wave element, and a cavity on the acoustic wave element; A step of covering the upper surface with the resin sealing portion and fixing the resin sealing portion so that the reinforcing layer is disposed on the cavity, and the step of forming the resin sealing portion includes: Including a step of forming a third resin layer having a recess to be the cavity on the second resin layer, and the step of fixing the resin sealing portion includes fixing the third resin layer to the substrate, the resin sealing portion is a step of fixing the substrate, the second resin layer and the third tree The layer is a photosensitive resin, and the step of forming the third resin layer is performed by developing the hole to form a through electrode in the second resin layer and the third resin layer, and the cavity to be the cavity. A method of manufacturing an acoustic wave device comprising a step of simultaneously forming recesses. According to this configuration, the third resin layer can be formed on the substantially flat second resin layer.

  In the above configuration, the step of forming the resin sealing portion on a support plate, the step of fixing the resin sealing portion is performed in a state where the resin sealing portion is formed on the support plate, It can be set as the structure which has the process of peeling the said support plate from the said resin sealing part. According to this configuration, the manufacturing cost can be reduced.

  The said structure WHEREIN: The said 1st resin layer can be set as the structure by which the opening which exposes the said reinforcement layer is formed. According to this configuration, the reinforcing layer can be electrically connected to the outside.

  According to the present invention, since the top of the reinforcing layer is made of the resin sealing portion having a small elastic modulus, the stress can be relaxed. Furthermore, since a reinforcing layer having a higher elastic modulus than the resin sealing portion is provided on the cavity, a hollow structure that is not deformed by pressure can be provided. Furthermore, since the resin sealing portion is also provided between the reinforcing layer and the cavity, stray capacitance can be suppressed.

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

1A is a plan view of the acoustic wave device 100 according to the first embodiment (the resin sealing portion is not shown, and the connection terminal 48, the reinforcing layer 30, and the cavity 16 are shown), and FIG. It is AA sectional drawing of Fig.1 (a). Referring to FIG. 1B, an acoustic wave element 12 made of a comb-shaped electrode is provided on a piezoelectric substrate 10 made of lithium tantalate (LiTaO ₃ ) or lithium niobate (LiNbO ₃ ). A resin sealing portion 20 made of an epoxy resin is provided so as to have a cavity 16 on the acoustic wave element 12 and cover the upper surface and side surfaces of the cavity 16. The resin sealing portion 20 includes a first resin layer 22, a second resin layer 24, and a third resin layer 26. A reinforcing layer 30 made of metal is sandwiched between the first resin layer 22 and the second resin layer 24 on the cavity 16. The through electrode 40 including the adhesion layer 42, the conductive layer 44, and the barrier layer 46 penetrates the resin sealing portion 20 except for the cavity 16, and is connected to the acoustic wave element 12 through the wiring 14. A connection terminal 48 made of solder is provided on the through electrode 40. Referring to FIG. 1A, the reinforcing layer 30 is disposed so as to be included in the cavity 16 in a plane viewed from above.

  In order to surface-mount the acoustic wave device 100, a through electrode 40 penetrating the resin sealing portion 20 is provided, a connection terminal 48 is provided on the through electrode 40, and the through electrode 40 and the connection terminal 48 are electrically connected. Is done. Stress is applied to the interface between the through electrode 40 and the connection terminal 48, that is, near the upper surface of the resin sealing portion 20 due to a difference in thermal expansion coefficient between the through electrode 40 and the connection terminal 48. Therefore, in order to suppress the occurrence of cracks in the vicinity of the upper surface of the resin sealing portion 20, it is preferable that the vicinity of the upper surface of the resin sealing portion 20 is made of a resin having a low elastic modulus. On the other hand, when the reinforcing layer 30 made of metal is disposed immediately above the cavity 16, the stray capacitance increases.

  The effect when the stray capacitance increases will be described with reference to FIGS. As shown in FIG. 2, the surface acoustic wave double mode filters 70 and 72 are connected between the input terminal In and the output terminal Out, and the case where the stray capacitance Cf is added between the input terminal In and the output terminal Out was simulated. FIG. 3 shows the simulation results of the pass characteristics when the stray capacitance Cf = 0 and when Cf = 10 pF. When the stray capacitance Cf is 10 pF, the amount of attenuation decreases and the suppression characteristic deteriorates on the low band side and the high band side outside the pass band. As described above, when the stray capacitance Cf increases, the suppression characteristic deteriorates.

  According to the first embodiment, since the upper surface is formed of the first resin layer 22 having a small elastic modulus, stress due to a difference in thermal expansion coefficient between the through electrode 40 and the connection terminal 48 can be reduced. In order to reduce the elastic modulus of the first resin layer 22, it is preferable not to contain a filler or the like. Further, since the reinforcing layer 30 having a larger elastic modulus than the first resin layer 22 is provided on the cavity 16, for example, the collapse of the cavity 16 due to the pressure of the transfer mold when the acoustic wave device 100 is made into a module is suppressed. can do. Furthermore, since the second resin layer 24 is provided between the reinforcing layer 30 and the cavity 16, stray capacitance can be suppressed. The reinforcing layer 30 is preferably made of a material having a higher elastic modulus at a molding temperature when the elastic wave device 100 is made into a module than the first resin layer 22 and the second resin layer 24. For example, a metal such as nickel or copper can be used. For example, the elastic modulus of a resin not using a filler is about 1 GPa or less at a molding temperature of 150 ° C. to 200 ° C., and the elastic modulus of nickel in this temperature range is about 200 GPa. The reinforcing layer 30 may be an insulator, but is preferably a metal in order to be easily formed with a material having a large elastic modulus.

  The reinforcing layer 30 is preferably completely surrounded by the resin sealing portion 20 and electrically separated from the acoustic wave element 12. Thereby, the process of electrically connecting the reinforcing layer 30 to the acoustic wave element 12 can be reduced.

  Example 2 is an example of a method of manufacturing an acoustic wave device according to Example 1. A method for manufacturing an acoustic wave device according to the second embodiment will be described with reference to FIGS. In Example 2, an elastic wave device is formed by fixing a support plate on which a plurality of resin sealing portions are formed on a wafer on which a plurality of elastic wave elements are formed. In the following drawings, one elastic wave device and one resin sealing portion are shown. Referring to FIG. 4A, a release layer 52 is formed on a support plate 50 such as a glass plate or a piezoelectric substrate. For example, a magnesium oxide layer having a thickness of 10 nm to 1 μm or a heat-resistant polyimide resin for lift-off having a thickness of 100 nm to 10 μm is used as the release layer 52. A first resin layer 22 made of a photosensitive epoxy resin having a thickness of 10 μm is applied and formed on the release layer 52. In order to make the 1st resin layer 22 into a low elasticity modulus, it is preferable not to contain a filler.

  Referring to FIG. 4B, the first resin layer 22 is processed into a predetermined shape by exposure and development. Referring to FIG. 4C, a seed metal 32 having a thickness of, for example, about 100 nm is formed on the release layer 52 and the first resin layer 22. Referring to FIG. 4D, a photoresist 60 is applied on the seed metal 32.

  With reference to FIG. 5A, an opening 62 is formed in the photoresist 60 by exposure and development. Referring to FIG. 5B, by supplying power through the seed metal 32, a plating layer 34 made of nickel having a thickness of, for example, about 5 μm is formed in the opening 62 using an electrolytic plating method. Referring to FIG. 5C, the photoresist 60 is removed. Referring to FIG. 5D, the seed metal 32 is removed using the plating layer 34 as a mask. Thereby, the reinforcing layer 30 is constituted by the seed metal 32 and the plating layer 34.

  With reference to FIG. 6A, the second resin layer 24 made of a photosensitive epoxy resin is applied on the release layer 52, the first resin layer 22, and the reinforcing layer 30. The film thickness of the second resin layer 24 is 20 μm, for example. With reference to FIG. 6B, by exposing and developing, a hole 64 in which a through electrode is to be formed and a groove 65 for a separation region are formed in the second resin layer 24. In addition, since the same pattern is arranged on the support plate 50, the code | symbol 65 comprises the groove | channel. Referring to FIG. 6C, a third resin layer 26 made of an adhesive photosensitive epoxy resin is applied. The film thickness of the third resin layer 26 on the second resin layer 24 is, for example, about 10 μm. With reference to FIG. 6D, by exposing and developing, a hole 64 in which a through electrode is to be formed, a groove 65 for a separation region, and a recess 66 to be a cavity are formed in the third resin layer 26. Thereby, the resin sealing portion 20 is formed from the first resin layer 22, the second resin layer 24, and the third resin layer 26.

  Referring to FIG. 7A, an acoustic wave element 12 made of a comb-shaped electrode made of, for example, an aluminum pattern and a wiring made of aluminum are formed on the piezoelectric substrate 10. An adhesion layer 42 is formed in a region where the through electrode is to be formed on the wiring 14. The support plate 50 shown in FIG. 6D is disposed on the wafer made of the piezoelectric substrate 10. At this time, alignment is performed so that the pattern on the piezoelectric substrate 10 and the pattern on the support plate 50 (lower in FIG. 7A) match. That is, the cavity 16 is disposed on the acoustic wave element 12 provided on the piezoelectric substrate 10 and the hole 64 is disposed on the adhesion layer 42. With reference to FIG. 7B, the third resin layer 26 is heated to, for example, 150 ° C. to 180 ° C. while being in contact with the piezoelectric substrate 10. Thereby, the third resin layer 26 is bonded and fixed to the piezoelectric substrate 10. In addition, the first resin layer 22, the second resin layer 24, and the third resin layer 26 are thermoset.

  Referring to FIG. 8A, the release layer 52 is etched and the support plate 50 is peeled off. As an etching solution for etching the release layer 52, acetic acid can be used when the release layer 52 is magnesium oxide, and an alkaline developer can be used when the release layer 52 is a heat-resistant polyimide resin for lift-off. With reference to FIG. 8B, a conductive layer 44 made of copper and a barrier layer 46 made of nickel are formed on the adhesion layer 42 in the hole 64. Thereby, the through electrode 40 is formed from the adhesion layer 42, the conductive layer 44, and the barrier layer 46. A connection terminal 48 made of solder is formed on the through electrode 40. Thereafter, the wafer which is the piezoelectric substrate 10 is cut by a dicing method or the like to complete the acoustic wave device according to FIG.

  According to Example 2, the reinforcing layer 30 is formed on the first resin layer 22 as shown in FIGS. As shown in FIGS. 6A and 6D, the second resin layer 24 is formed so as to cover the reinforcing layer 30, and the resin is formed from the first resin layer 22, the second resin layer 24, and the third resin layer 26. The sealing part 20 is formed. As shown in FIGS. 7A and 7B, on the piezoelectric substrate 10 on which the acoustic wave element 12 is provided, the cavity 16 is provided on the acoustic wave element 12, and the side surface and the upper surface of the cavity 16 are resin-sealed. The resin sealing portion 20 is fixed so that the portion 20 is covered and the reinforcing layer 30 is disposed on the cavity 16. Thereby, the reinforcing layer 30 sandwiched between the resin sealing portions 20 can be disposed on the individual acoustic wave elements 12 in a wafer state. Therefore, unlike the conventional example 6, it is not necessary to individually arrange the reinforcing layer 30 on each acoustic wave element 12, and the manufacturing cost can be reduced.

  Further, as shown in FIG. 8B, a through electrode 40 that penetrates the resin sealing portion 20 and is electrically connected to the acoustic wave element 12 is formed except for the cavity 16. Further, the connection terminal 48 is formed on the through electrode 40. The stress caused by the through electrode 40 or the connection terminal 48 is relaxed by the first resin layer 22, and the strength of the resin sealing portion 20 on the cavity 16 can be ensured by the reinforcing layer 30.

  Furthermore, as shown in FIG. 5B, the reinforcing layer 30 is preferably formed using a plating method. Thereby, the some reinforcement layer 30 can be formed at once.

  Further, as shown in FIG. 6C and FIG. When forming the resin sealing portion 20, the third resin layer 26 having the recess 66 that should become the cavity 16 is formed on the second resin layer 24. 7A and 7B, the resin sealing portion 20 is fixed to the piezoelectric substrate 10 by fixing the third resin layer 26 to the piezoelectric substrate 10. Thus, the cavity 16 can be easily formed by using the third resin layer 26.

  Further, the third resin layer 26 is an adhesive resin, and the resin sealing portion 20 is bonded to the piezoelectric substrate 10 using the third resin layer 26 as shown in FIG. In this way, the manufacturing process can be reduced by using the third resin layer 26 having the recess 66 that becomes the cavity 16 also as an adhesive.

  Further, the resin sealing portion 20 is formed on the support plate 50 as shown in FIGS. As shown in FIGS. 7A and 7B, the resin sealing portion 20 is fixed to the piezoelectric substrate 10 in a state where the resin sealing portion 20 is formed on the support plate 50. As shown in FIG. 8A, the support plate 50 is peeled from the resin sealing portion 20. Thereby, the resin sealing part 20 can be fixed on the piezoelectric substrate 10 provided with the plurality of acoustic wave elements in a state where the resin sealing parts 20 are arranged on the support plate 50. Therefore, the manufacturing cost can be reduced as compared with the case where the resin sealing portion 20 is individually formed on the acoustic wave element 12. Further, when the reinforcing layer 30 is formed on the second resin layer 24 after the third resin layer and the second resin layer 24 are formed on the piezoelectric substrate 10, the reinforcement is performed in a state where the hole 64 for the through electrode 40 is formed. Layer 30 will be formed. For this reason, the reinforcement layer 30 will be formed on resin with a large unevenness | corrugation. On the other hand, according to Example 2, the reinforcing layer can be formed on a relatively flat resin as shown in FIGS. 4 (a) to 5 (d). Therefore, the reinforcing layer 30 can be easily formed.

  A method for manufacturing an acoustic wave device according to Example 3 will be described with reference to FIGS. 9A to 9D. With reference to FIG. 9A, the steps of FIG. 4A to FIG. 6A of Example 2 are performed. Here, the second resin layer 24 is a negative photosensitive resin. Referring to FIG. 9B, the second resin layer 24 to be left is exposed to ultraviolet rays. Referring to FIG. 9C, a negative photosensitive epoxy resin having adhesiveness is applied on the second resin layer 24. The third resin layer 26 to be left is exposed to ultraviolet rays. With reference to FIG. 9D, a hole 64, a groove 65, and a recess 66 penetrating the second resin layer 24 and the third resin layer 26 are formed by development. Hereinafter, the elastic wave device according to the third embodiment is completed by performing the steps of FIG. 7A to FIG. 8B of the second embodiment.

  According to Example 3, the second resin layer 24 and the third resin are selected as shown in FIG. 9D by selecting a material that does not affect the development of the second resin layer 24 by applying the third resin layer 26. By developing the layer 26 at the same time, it is possible to simultaneously form the hole 64 in which the through electrode is to be formed, the groove 65, and the recess 66 to be a cavity in the second resin layer 24 and the third resin layer 26. Thereby, the third resin layer 26 can be formed on the substantially flat second resin layer 24 as shown in FIG. Therefore, the uniformity of the film thickness of the third resin layer 26 can be improved. Moreover, since the 2nd resin layer 24 and the 3rd resin layer 26 are developed simultaneously, the process of developing can be reduced.

  Example 4 is an example in which an adhesive is used separately from the third resin layer. A method for manufacturing an acoustic wave device according to Example 4 will be described with reference to FIGS. Referring to FIG. 10A, the steps up to FIG. 9D of Example 3 are performed. Here, as the third resin layer 26a, a photosensitive epoxy resin having no adhesiveness is used. Referring to FIG. 10B, an etching solution is introduced through the hole 64 and the groove 65 to partially etch the upper portion of the peeling layer 52. Thereby, the taper-shaped recessed part 57 is formed in the peeling layer 52a. Referring to FIG. 10C, an adhesive layer 54 made of an adhesive epoxy resin is applied. Thereby, the adhesive layer 54 is formed on the resin sealing portion 20 and on the inner surfaces of the hole 64, the groove 65, and the recess 66.

  Referring to FIG. 11A, the resin sealing portion 20 is bonded to a wafer that is the piezoelectric substrate 10 provided with the acoustic wave element 12 while being bonded to the support plate 50. The adhesive layer 54 is cured, and the resin sealing portion 20 and the piezoelectric substrate 10 are bonded. Referring to FIG. 11B, using a dicing device or the like, the support plate 50 is cut and a groove 69 is formed so as to reach the release layer 52a. Referring to FIG. 12A, the peeling layer 52 a is etched through the groove 69. Thereby, the support plate 50 is peeled off. In FIG. 10B, since the recess 57 is formed in the release layer 52a, a bridge 54a of the adhesive layer 54 is formed above the hole 64 and the groove 65. Referring to FIG. 12B, the bridge 54a of the adhesive layer 54 is removed by performing pressure such as air jetting, sticking and peeling of the adhesive tape, and the like. Thus, since the recessed part 57 was formed in the peeling layer 52a and the contact bonding layer 54 was used as the bridge 54a, the bridge 54a can be removed easily. Thereafter, by performing the process of FIG. 8B of Example 2, the acoustic wave device according to Example 4 is completed.

  According to Example 4, as shown in FIG. 10C, the adhesive layer 54 is formed so as to cover the third resin layer 26a. As shown in FIG. 11A, the resin sealing portion 20 is bonded to the piezoelectric substrate 10 using the adhesive layer 54. Accordingly, it is not necessary to use an adhesive resin as the third resin layer 26a as in the second and third embodiments. Further, it is not necessary to use a photosensitive resin as the adhesive layer 54. Therefore, the room for material selection for the third resin layer 26a and the adhesive layer 54 can be expanded. For example, an appropriate material can be selected for cost and physical properties (for example, thermal expansion coefficient and elastic modulus) of the third resin layer 26a and the adhesive layer.

  Example 5 is an example in which the reinforcing layer 30 made of metal can be connected to the outside. A method for manufacturing an acoustic wave device according to Example 5 will be described with reference to FIGS. With reference to FIG. 13A, the first resin layer 22 a is formed on the release layer 52 formed on the support plate 50. The first resin layer 22 a has an opening 68. With reference to FIG.13 (b), the process similar to FIG.4 (c) to FIG.5 (d) of Example 2 is performed, and the reinforcement layer 30 is formed on the 1st resin layer 22a. The reinforcing layer 30 is also formed in the opening 68 of the first resin layer 22a. With reference to FIG.13 (c), the process similar to FIG. 6 (a)-FIG.8 (b) of Example 2 is performed. Furthermore, when forming the connection terminal 48, the connection terminal 48a connected to the reinforcement layer 30 via the 1st resin layer 22a is formed. Thus, the acoustic wave device according to Example 4 is completed.

  According to Example 5, the hole 64 (opening) which exposes the reinforcement layer 30 is formed in the 1st resin layer 22a. Thereby, the reinforcement layer 30 can be connected to the exterior and electricity. For example, the stray capacitance Cf can be reduced by connecting the reinforcing layer 30 to the ground. Therefore, the suppression characteristics on the low frequency side and the high frequency side outside the pass band can be improved from FIG.

  Example 6 is an example in which the shape of the reinforcing layer is changed. Referring to FIG. 14A, the reinforcing layer 30a can be formed in a lattice shape. Further, referring to FIG. 14B, the reinforcing layer 30b can be formed in a stripe shape. Furthermore, referring to FIG. 14C, the reinforcing layer 30c can be formed in a dot shape. In order to reduce the stray capacitance Cf, the reinforcing layer is preferably small, and is preferably large in order to maintain the strength of the resin sealing portion 20. Considering these, the shape of the reinforcing layer can be appropriately set.

  In Examples 1 to 5, two acoustic wave elements 12 and two cavities 16 are formed, but the number is not limited thereto. As the 1st resin layer 22, the 2nd resin layer 24, and the 3rd resin layer 26, a polyimide resin, a silicon resin, etc. can be used besides an epoxy resin. The resin is not limited to these, and any resin that protects the acoustic wave element 12 may be used. Although the solder balls have been described as examples of the connection terminals 48, they may be made of other metals. When the materials of the through electrode 40 and the connection terminal 48 are different, stress is applied particularly in the vicinity of the upper surface of the resin sealing portion 20, and therefore, the first resin layer 22 having a low elastic modulus is disposed on the upper surface of the resin sealing portion 20 for reinforcement It is more effective to embed the layer 30 in the resin sealing portion 20.

  As the acoustic wave element 12, the surface acoustic wave element provided on the piezoelectric substrate 10 has been described as an example, but a piezoelectric thin film resonant element may be used. In the case of the piezoelectric thin film resonant element, the substrate may be a silicon substrate other than the piezoelectric substrate 10, a glass substrate, a quartz substrate, or the like.

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

FIG. 1A is a plan view of an acoustic wave device according to the first embodiment, and FIG. 1B is a cross-sectional view taken along line AA in FIG. FIG. 2 is a schematic circuit diagram used for the simulation. FIG. 3 is a simulation result of the pass characteristics with and without stray capacitance. FIG. 4A to FIG. 4D are cross-sectional views (part 1) illustrating the manufacturing process of the acoustic wave device according to the second embodiment. FIG. 5A to FIG. 5D are cross-sectional views (part 2) illustrating the manufacturing process of the acoustic wave device according to the second embodiment. FIG. 6A to FIG. 6D are cross-sectional views (part 3) illustrating the manufacturing process of the acoustic wave device according to the second embodiment. FIG. 7A and FIG. 7B are cross-sectional views (part 4) illustrating the manufacturing process of the acoustic wave device according to the second embodiment. 8A and 8B are cross-sectional views (part 5) illustrating the manufacturing process of the acoustic wave device according to the second embodiment. FIG. 9A to FIG. 9D are cross-sectional views illustrating the manufacturing steps of the acoustic wave device according to the third embodiment. FIG. 10A to FIG. 10C are cross-sectional views (part 1) illustrating the manufacturing process of the acoustic wave device according to the fourth embodiment. 11A and 11B are cross-sectional views (part 2) illustrating the manufacturing process of the acoustic wave device according to the fourth embodiment. 12A and 12B are cross-sectional views (part 3) illustrating the manufacturing process of the acoustic wave device according to the fourth embodiment. FIG. 13A to FIG. 13C are cross-sectional views illustrating the manufacturing steps of the acoustic wave device according to the fifth embodiment. FIG. 14A to FIG. 14C are plan views showing the cavity and the reinforcing layer of the acoustic wave device according to the sixth embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Piezoelectric substrate 12 Elastic wave element 14 Wiring 20 Resin sealing part 22 1st resin layer 24 2nd resin layer 26 3rd resin layer 30 Reinforcing layer 40 Through electrode 48 Connection terminal 50 Support plate 52 Peeling layer 54 Adhesive layer

Claims (12)

An acoustic wave element provided on a substrate;
A resin sealing portion provided on the substrate so as to have a cavity on the acoustic wave element and cover a side surface and an upper surface of the cavity;
A through-electrode that penetrates the resin sealing portion and is electrically connected to the acoustic wave element except for the cavity;
A connection terminal provided on the through electrode;
A reinforcing layer made of a metal having a higher elastic modulus than that of the resin sealing portion and electrically separated from the acoustic wave element; Elastic wave device characterized by.   2. The acoustic wave device according to claim 1, wherein the reinforcing layer is completely surrounded by the resin sealing portion. Forming a reinforcing layer made of a metal having a larger elastic modulus than the first resin layer on the first resin layer;
Forming a second resin layer having a smaller elastic modulus than the reinforcing layer so as to cover the reinforcing layer, and forming a resin sealing portion including the first resin layer and the second resin layer;
On the substrate provided with the acoustic wave element, the acoustic wave element has a cavity, the side surface and the upper surface of the cavity are covered with the resin sealing portion, the reinforcing layer is disposed on the cavity, and the reinforcing layer Fixing the resin sealing portion so that is electrically separated from the acoustic wave element ,
A method for producing an acoustic wave device, comprising:   The method for manufacturing an acoustic wave device according to claim 3, further comprising a step of forming a through electrode that penetrates the resin sealing portion and is electrically connected to the acoustic wave element, other than the cavity.   The method for manufacturing an acoustic wave device according to claim 4, further comprising a step of forming a connection terminal on the through electrode.   6. The method for manufacturing an acoustic wave device according to claim 3, wherein the reinforcing layer is formed using a plating method. The step of forming the resin sealing portion includes the step of forming a third resin layer having a recess to be the cavity on the second resin layer,
The step of fixing the resin sealing portion is a step of fixing the resin sealing portion to the substrate by fixing the third resin layer to the substrate. The manufacturing method of the elastic wave device as described in any one of Claims. The third resin layer is an adhesive resin;
The method for manufacturing an acoustic wave device according to claim 7, wherein the step of fixing the resin sealing portion is a step of bonding the resin sealing portion to the substrate using the third resin layer. Forming an adhesive layer so as to cover the third resin layer;
The method for manufacturing an acoustic wave device according to claim 7, wherein the step of fixing the resin sealing portion is a step of bonding the resin sealing portion to the substrate using the adhesive layer. Forming a reinforcing layer having a larger elastic modulus than the first resin layer on the first resin layer;
Forming a second resin layer having a smaller elastic modulus than the reinforcing layer so as to cover the reinforcing layer, and forming a resin sealing portion including the first resin layer and the second resin layer;
On the substrate on which the acoustic wave element is provided, the cavity is formed on the acoustic wave element, the resin sealing portion covers the side surface and the upper surface of the cavity, and the reinforcing layer is disposed on the cavity. Fixing the resin sealing part;
Have
The step of forming the resin sealing portion includes the step of forming a third resin layer having a recess to be the cavity on the second resin layer,
The step of fixing the resin sealing portion is a step of fixing the resin sealing portion to the substrate by fixing the third resin layer to the substrate.
The second resin layer and the third resin layer are photosensitive resins,
The step of forming the third resin layer includes a step of simultaneously forming a hole in which a through electrode is to be formed in the second resin layer and the third resin layer and the concave portion to be the cavity by developing. A method for manufacturing an acoustic wave device. Having a step of forming the resin sealing portion on a support plate;
The step of fixing the resin sealing portion is performed in a state where the resin sealing portion is formed on the support plate,
The method for manufacturing an acoustic wave device according to claim 3, further comprising a step of peeling the support plate from the resin sealing portion.   The method for manufacturing an acoustic wave device according to claim 3, wherein an opening for exposing the reinforcing layer is formed in the first resin layer.

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