JP6556081B2 - Surface acoustic wave device - Google Patents

Description

  The present invention relates to a surface acoustic wave device having a functional body provided on an element substrate.

  The surface acoustic wave device includes a surface acoustic wave element having a device substrate and a functional body (for example, an IDT electrode) provided on the device substrate, and a circuit wiring board. In the surface acoustic wave device, the element electrode pads on the element substrate are provided on a wiring pattern extending from the functional body to the outer peripheral side of the element substrate, and solder bumps are formed on the substrate electrode pads on the circuit wiring board facing the element electrode pads. It is electrically connected via. An example of such a structure is disclosed in Patent Document 1.

JP 2004-201285 A

  In the above-described surface acoustic wave device, for example, when a stress that pulls the surface acoustic wave element upward with respect to the surface acoustic wave element is generated, the surface acoustic wave element is easily lifted upward, and the element electrode pad and the solder bump There is a problem that peeling between the substrate electrode pad and the solder bump is likely to occur.

  The present invention has been made in view of the above problems, and an object thereof is an elastic surface capable of suppressing peeling between an element electrode pad and a solder bump or between a substrate electrode pad and a solder bump. It is to provide a wave device.

A surface acoustic wave device according to an aspect of the present invention includes a circuit wiring board, a surface acoustic wave element mounted on the surface of the circuit wiring board with one main surface facing each other via solder bumps, and the surface acoustic wave. A sealing resin that is bonded to a side surface of the wave element and the circuit wiring board, and that seals a facing space between the surface of the circuit wiring board and the one main surface of the surface acoustic wave element. The sealing resin includes a frame-shaped first sealing resin provided on the circuit wiring board so as to surround the surface acoustic wave element, the other main surface of the surface acoustic wave element, and the first 1 is provided on the first sealing resin so as to cover the side surface of the surface acoustic wave element located above the first sealing resin, and has an elastic modulus smaller than that of the first sealing resin. A second sealing resin, and the first sealing tree The inner wall surface is located away from the side surface of the surface acoustic wave element, and the second sealing resin faces the upper surface of the first sealing resin in the thickness direction of the surface acoustic wave element. The lower surface is located below the center of the side surface of the surface acoustic wave element, and is also provided between the side surface of the surface acoustic wave element and the inner wall surface of the first sealing resin. The surface acoustic wave element is adhered to the side surface.

  According to the surface acoustic wave device of the present invention, the stress applied to the surface acoustic wave element can be relaxed by forming the sealing resin into a two-layer structure having a different elastic modulus.

(A) is a schematic longitudinal cross-sectional view for demonstrating the surface acoustic wave apparatus which concerns on Embodiment 1 of this invention, (b) is the positional relationship of a surface acoustic wave element and 1st sealing resin. It is a top view for demonstrating. 1 is a perspective view illustrating a surface acoustic wave device according to Embodiment 1 of the present invention as seen through from above. (A) is a schematic longitudinal cross-sectional view for demonstrating the surface acoustic wave apparatus which concerns on Embodiment 2 of this invention, (b) is the positional relationship of a surface acoustic wave element and 1st sealing resin. It is a top view for demonstrating. (A) is a schematic longitudinal cross-sectional view for demonstrating the other example of the surface acoustic wave apparatus which concerns on Embodiment 1 of this invention, (b) is a surface acoustic wave element and 1st sealing resin. It is a top view for demonstrating the positional relationship with these. (A) is a schematic longitudinal cross-sectional view for demonstrating the other example of the surface acoustic wave apparatus which concerns on Embodiment 2 of this invention, (b) is a surface acoustic wave element and 1st sealing resin. It is a top view for demonstrating the positional relationship with these.

  Hereinafter, a surface acoustic wave device according to an embodiment of the present invention will be described with reference to the drawings. Note that the drawings used in the following description are schematic, and the dimensional ratios and the like on the drawings do not necessarily match the actual ones. In the surface acoustic wave device, either direction may be set upward or downward, but for convenience of explanation, an orthogonal coordinate system XYZ is defined, and the positive side in the Z direction is used as the upper side, and the word “upper surface” or “lower surface” is used. And

  In the description of the embodiments and the like, components that are the same as or similar to those already described may be assigned the same reference numerals and descriptions thereof may be omitted.

<Embodiment 1>
A surface acoustic wave device 10 according to an embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

A surface acoustic wave device 10 according to the first embodiment is configured as shown in FIGS. 1 and 2 and includes a surface acoustic wave element 2. The surface acoustic wave element 2 includes an element substrate 2a and an element substrate. A plurality of functional bodies 2b provided in 2a, an element electrode pad 3 provided around the functional body 2b, and extending from the functional body 2b toward the element electrode pad 3, and electrically connected to the element electrode pad 3 And a connected wiring pattern 6. The surface acoustic wave element 2 has an element substrate 2 a and a plurality of functional bodies 2 b formed on one main surface of the element substrate 2 a, and has a facing space S between the circuit substrate 1 and the circuit substrate 1. And mounted on the circuit wiring board 1 via the solder bumps 5.

  The surface acoustic wave element 2 is provided with a plurality of functional bodies 2b on one main surface of a rectangular element substrate 2a in plan view, with one main surface facing the surface (upper surface) of the circuit wiring board 1. It is mounted via solder bumps 5. In the surface acoustic wave element 2, a plurality of element electrode pads 3 are provided around the plurality of functional bodies 2b. The functional body 2 b is electrically connected to the element electrode pad 3 through the wiring pattern 7.

  In addition, the circuit wiring board 1 is provided with a plurality of substrate electrode pads 4 on the main surface (the surface of the circuit wiring board 1) opposite to one main surface of the element substrate 2a. And electrically connected to the element electrode pad 3.

  FIG. 2 is a perspective view showing a state in which the surface acoustic wave device 10 is seen through from above, and shows a plurality of functional bodies 2 b, element electrode pads 3, and wiring patterns 6 on the element substrate 2 a of the surface acoustic wave element 2. ing. FIG. 2 shows a state including the sealing resin 7. The surface acoustic wave element 2 has a plurality of functional bodies 2b provided on one main surface (lower surface) of the element substrate 2a, and has a substantially rectangular parallelepiped shape, for example.

  In the surface acoustic wave element 2, as shown in FIG. 2, a plurality of element electrode pads 3 are arranged around the functional body 2b of the element substrate 2a, and are electrically connected to the respective wiring patterns 6. Yes. The wiring pattern 6 is provided on the element substrate 2a, is connected to the functional body 2b, and faces the element electrode pad 3 from the functional body 2b. In this way, the wiring pattern 6 extends from the functional body 2b toward the element electrode pad 3, and is provided along the outer periphery of the square element substrate 2a, for example, and is electrically connected to the element electrode pad 3. It is connected to the. The surface acoustic wave element 2 is provided with an intermediate wiring for electrically connecting the functional bodies 2b to one main surface of the element substrate 2a. The intermediate wiring is included in the wiring pattern 6. To do.

  The element electrode pad 3 is provided along the outer periphery of the rectangular element substrate 2 a and is provided at the end of the wiring pattern 6 or in the middle of the wiring pattern 6. There are also things. The element electrode pads 3 include those that are electrically connected to the wiring pattern 6 or those that are not electrically connected to the wiring pattern 6.

  As shown in FIG. 1, the surface acoustic wave device 10 has a sealing resin 7 bonded to the side surface 2 d of the surface acoustic wave element 2 and the surface (upper surface) of the circuit wiring board 1. The facing space S between one main surface of the surface acoustic wave element 2 is sealed. As shown in FIG. 1, the sealing resin 7 includes a first sealing resin 7a and a second sealing resin 7b provided on the first sealing resin 7a.

  As described above, in the surface acoustic wave device 10, the sealing resin 7 has the other main surface of the surface acoustic wave element 2 (the main surface opposite to the one main surface of the element substrate 2a) and the side surface 2d of the surface acoustic wave element 2. It is provided so as to cover. The thickness of the sealing resin 7 is, for example, 0.2 (mm) to 0.8 (mm). The sealing resin 7 is made of a resin material such as an epoxy resin, for example.

  As shown in FIG. 1, the first sealing resin 7 a is provided in a frame shape on the circuit wiring board 1 so as to surround the surface acoustic wave element 2. Further, the second sealing resin 7b covers the first sealing so as to cover the other main surface of the surface acoustic wave element 2 and the side surface 2d of the surface acoustic wave element 2 located above the first sealing resin 7a. It is provided on the stop resin 7a. The second sealing resin 7b covers the upper surface of the first sealing resin 7a.

FIG. 1B shows the positional relationship between the surface acoustic wave element 2 and the first sealing resin 7 a in the surface acoustic wave device 10. The first sealing resin 7 a is provided in a frame shape, surrounds the surface acoustic wave element 2, the inner wall surface 7 aa is positioned in contact with the side surface 2 d of the surface acoustic wave element 2, and faces the inner wall surface 7 aa. The surface acoustic wave element 2 is bonded to the side surface 2d.

  1A, in the thickness direction of the surface acoustic wave element 2 (thickness direction of the element substrate 2), the second sealing resin 7b has a lower surface 7ba on the side surface 2d of the surface acoustic wave element 2. The surface acoustic wave element 2 is bonded to the side surface 2 d of the surface acoustic wave element 2. As shown in FIG. 1A, the lower surface 7ba of the second sealing resin 7b faces the upper surface of the first sealing resin 7a. In addition, the upper surface of the first sealing resin 7a and the lower surface 7ba of the second sealing resin 7b are provided so as to be flat, but the surface is not limited to flat, for example, the surface is uneven. The shape of the surface is not limited.

  As described above, in the thickness direction of the surface acoustic wave element 2, the first sealing resin 7 a is provided such that the upper surface is positioned below the center X of the side surface 2 d of the surface acoustic wave element 2. That is, the second sealing resin 7 b is provided such that the lower surface 7 ba is positioned below the center X of the side surface 2 d of the surface acoustic wave element 2. Therefore, in the surface acoustic wave device 10, the proportion of the second sealing resin 7b in the side surface 2d of the surface acoustic wave element 2 is large. A side surface 2d of the surface acoustic wave element 2 is a side surface of the element substrate 2a.

  As shown in FIG. 1, the distance H1 between the upper surface of the first sealing resin 7a and the center X of the side surface 2d of the element substrate 2a is, for example, 0 (μm) <H1 <200 (μm).

  The first sealing resin 7a is made of, for example, a resin material containing a curing agent such as phenol and acid anhydride based on an epoxy resin, and the second sealing resin 7b is made of, for example, phenol based on an epoxy resin. It consists of a resin material containing a curing agent such as an acid anhydride or an acid anhydride.

  The first sealing resin 7a has an elastic modulus of, for example, 0.3 (Pa) to 1 (Pa), and the second sealing resin 7b is smaller than the first sealing resin 7a. It has an elastic modulus, and the elastic modulus is, for example, 0.05 (Pa) to 0.3 (Pa). The first sealing resin 7a and the second sealing resin 7b can have a desired elastic modulus, for example, by adjusting the glass transition temperature. In order to make the above-mentioned elastic modulus range, the first sealing resin 7a has a glass transition temperature in the range of 20 (° C.) to 120 (° C.), for example, and the second sealing resin 7b. Has, for example, a glass transition temperature in the range of 20 (° C.) to 60 (° C.).

  Thus, in the surface acoustic wave device 10, the lower surface 7 ba of the second sealing resin 7 a is located below the center X of the side surface 2 d of the surface acoustic wave element 2. That is, the sealing resin 7 is such that the upper surface of the first sealing resin 7a is positioned below the center X of the side surface 2d of the surface acoustic wave element 2, and the second sealing resin 7b is the first sealing resin. The elastic modulus is smaller than the elastic modulus of the resin 7a. The surface acoustic wave device 10 is likely to generate a stress that pulls the surface acoustic wave element 2 upward (Z direction) when the sealing resin 7 is thermally expanded. Further, the stress that pulls the surface acoustic wave element 2 upward (Z direction) is likely to be generated from the central portion of the side surface 2 d of the surface acoustic wave element 2 in the thickness direction of the surface acoustic wave element 2.

  In the surface acoustic wave device 10, the second sealing resin 7 b has a smaller elastic modulus than the first sealing resin 7 a, and the second sealing resin 7 b serves as the side surface 2 d of the surface acoustic wave element 2. Since the bonding is performed so as to cover more than half including the central portion of the surface, the stress that pulls up the surface acoustic wave element 2 generated when the sealing resin 7 thermally expands is relieved by the second sealing resin 7b. be able to.

Therefore, since the surface acoustic wave device 10 can relieve the stress that pulls the surface acoustic wave element 2 upward, it is between the element electrode pad 3 and the solder bump 5 or between the substrate electrode pad 4 and the solder bump 5. Can be prevented.

  Further, since the inner wall surface 7aa of the first sealing resin 7a is bonded to the side surface 2d of the surface acoustic wave element 2, the surface acoustic wave device 10 is made of the first sealing resin 7a having a large elastic modulus and has an elastic surface. The side surface 2d of the wave element 2 can be held. Thus, when the surface acoustic wave device 10 is mounted on the circuit wiring board 1, the surface acoustic wave element 2 is protected by the first sealing resin 7 a against pressure from the upper surface or the side surface. As a result, the surface acoustic wave device 10 can suppress damage to the surface acoustic wave element 2 against external pressure.

  In the surface acoustic wave element 2, for example, a signal is input via any one of the plurality of element electrode pads 3 on the one main surface (lower surface), and the input signal is subjected to predetermined processing to be processed. A signal is output from either of the above. In the surface acoustic wave element 2, a plurality of element electrode pads 3 are provided in an appropriate number on one main surface (lower surface) of the element substrate 2a. The element electrode pad 3 has a shape, number, formation position, and role. Are appropriately set according to the internal configuration of the surface acoustic wave element 2 and the like.

  Further, as shown in FIG. 1, the surface acoustic wave element 2 is provided with a protective film 2 c so as to cover the functional body 2 b on one main surface of the element substrate 2 a, and the element electrode pad 3 on the wiring pattern 6. It is provided so that the formation region is exposed. That is, the protective film 2c is provided over almost the entire lower surface of the element substrate 2a except for the region where the element electrode pad 3 is formed. The element electrode pad 3 is provided on the wiring pattern 6 exposed from the protective film 2c.

Specifically, the protective film 2c is provided on the element substrate 2a so as to cover the functional body 2b and the wiring pattern 6 by using, for example, a CVD (Chemical Vapor Deposition) method or a sputtering method. Then, the protective film 2 c provided on the wiring pattern 6 is removed using a known photolithography method or the like, and the formation region of the element electrode pad 3 is exposed on the wiring pattern 6. For example, the element electrode pad 3 is provided on the wiring pattern 6 exposed from the protective film 2c by providing a metal layer on the wiring pattern 6 exposed from the protective film 2c by sputtering.

  The protective film 2c is made of an insulating material such as silicon oxide, aluminum oxide, or silicon nitride. The thickness of the protective film 2c is, for example, 5 (nm) to 30 (nm).

  In the surface acoustic wave element 2, the functional body 2b and the wiring pattern 6 connected to the functional body 2b are formed of a conductive layer. For example, the conductive layer of the functional body 2b and the wiring pattern 6 is formed of the same conductive material. At the same time, it can be formed on the element substrate 2a. Any of the conductive layers is Al or Al alloy (for example, Al-Cu, Al-Si-Cu, or Al-Ti), Cu or Cu alloy (for example, Cu-Mg or Cu-Ti), A metal material such as Ag or an Ag alloy (for example, Ag—Mg or Ag—Ti) can be used. In addition, the conductive layer may be a single layer made of a single conductive material, or may be a laminate formed by stacking a plurality of conductive materials. The functional body 2b and the wiring pattern 6 may be partially formed of different conductive materials. The functional body 2b and the wiring pattern 6 have a thickness of, for example, 100 (nm) to 500 (nm).

  As shown in FIG. 2, the element electrode pad 3 is made of a metal material such as Al or Al alloy (for example, Al—Cu, Al—Si—Cu, or Al—Ti), as with the wiring pattern 6. A barrier metal layer is formed on the surface of the conductive layer for the purpose of improving the bondability with the solder bump 5. As the barrier metal layer, for example, a chromium (Cr) layer, a nickel (Ni) layer, and a gold (Au) layer are formed thereon by using a sputtering method.

  The functional body 2b and the wiring pattern 6 are provided on the element substrate 2a as follows. Specifically, first, a metal layer (conductive layer) to be the functional body 2b and the wiring pattern 6 is formed on one main surface (lower surface) of the element substrate 2a by using a thin film forming method such as a sputtering method or a vapor deposition method. Is done. Next, the functional body 2b and the wiring pattern 6 can be formed by patterning the formed metal layer using a known photolithography method or the like.

Further, as described above, the protective layer 2c is formed on the element substrate 2a so as to cover the functional body 2b and the wiring pattern 6 by using, for example, a CVD (Chemical Vapor Deposition) method. Then, the protective film 2c in the region where the element electrode pad 3 is formed is removed by using a well-known photolithography method or the like on the formed protective film 2c. That is, the protective film 2c on the wiring pattern 6 in the region where the element electrode pad 3 is formed is removed.

  Furthermore, the element electrode pad 3 is formed with a metal layer (conductive layer) to be the element electrode pad 3 on the wiring pattern 6 by using, for example, a sputtering method. Next, the element electrode pad 3 can be formed by patterning the formed metal layer using a known photolithography method or the like. Thus, the element electrode pad 3 is provided on the wiring pattern 6. The substrate electrode pad 4 has a thickness of, for example, 1 (μm) to 25 (μm).

  In the surface acoustic wave element 2, the element substrate 2a has a thickness of, for example, 50 (μm) to 400 (μm), and the length of the long side and the short side in plan view is, for example, 0.4. (Mm) to 3 (mm). The thickness of the element substrate 2a and the lengths of the long side and the short side in plan view can be set to appropriate thicknesses and lengths.

  In the surface acoustic wave device 10, the surface acoustic wave element 2 is mounted on the upper surface of the circuit wiring board 1 with one main surface of the element substrate 2a (the lower surface of the element substrate 2a) facing the surface. Further, the circuit wiring board 1 is provided with a plurality of substrate electrode pads 4 on a main surface (upper surface) opposite to one main surface of the element substrate 2a, and the substrate electrode pads 4 correspond to the corresponding element electrode pads. 3 is electrically connected via solder bumps 5.

  The surface acoustic wave element 2 is disposed so that the element substrate 2a is opposed to the surface of the circuit wiring board 1 so as to form a facing space S between the surface of the circuit wiring board 1 and the surface of the circuit wiring board 1. . As described above, the element electrode pad 3 and the substrate electrode pad 4 are electrically connected via the solder bumps 5 so as to have the facing space S between the element substrate 2 a and the circuit wiring board 1. The solder bump 5 is made of, for example, a solder material such as Sn—Ag, Sn—Ag—Cu, or Sn—Bi, or a high melting point solder material containing Pb. In the surface acoustic wave device 10, the thickness of the solder bump 5 is, for example, 10 (μm) to 100 (μm), and the distance between the circuit wiring board 1 and the element substrate 2 a (including the protective film 2 c) is, for example, 10 (μm) to 130 (μm).

  As described above, the surface acoustic wave element 2 is provided with the functional body 2b on one main surface of the element substrate 2a, and the surface acoustic wave device 10 includes the surface acoustic wave element 2 on one main surface (function) of the element substrate 2a. It is mounted on the circuit wiring board 1 so as to have an opposing space S for vibration between the body 2b) and the main surface of the circuit wiring board 1.

The element substrate 2a is a piezoelectric substrate, and is formed in a generally thin rectangular parallelepiped shape as shown in FIGS. The element substrate 2a is composed of a single crystal substrate having piezoelectricity such as a lithium tantalate single crystal or a lithium niobate single crystal. The planar shape and various dimensions of the element substrate 2a may be set as appropriate. The element substrate 2a has, for example, a quadrangular shape in plan view, a thickness that is constant, for example, is set as appropriate, and is, for example, 50 (μm) to 300 (μm), and is long in plan view. The lengths of the side and the short side are, for example, 0.5 (mm) to 1.5 (mm). Further, the element substrate 2a may be formed of a so-called bonded substrate.

  As shown in FIGS. 1 and 2, the surface acoustic wave element 2 has a plurality of functional bodies 2b provided on one main surface (lower surface) of the element substrate 2a. Inter Digital transducer) electrode 2b1 and two reflectors 2b2, which are so-called SAW resonators.

As shown in FIG. 2, the IDT electrode 2 b 1 has a pair of comb electrodes arranged so as to mesh with each other (a plurality of electrode fingers alternate with each other). Each comb electrode of the IDT electrode 2b1 includes a bus bar and a plurality of electrode fingers extending from the bus bar in a direction perpendicular to the longitudinal direction of the bus bar. The pitch of the plurality of electrode fingers is generally constant. Actually, the IDT electrode 2b1 may be provided to have more electrode fingers.

  As shown in FIG. 2, the reflector 2b2 is provided so as to sandwich the IDT electrode 2b1 from both sides, and has a pair of bus bars and a plurality of electrode fingers extending between the pair of bus bars. The pitch of the plurality of electrode fingers is substantially constant and is substantially the same as the pitch of the plurality of electrode fingers of the IDT electrode 2b1.

  As shown in FIG. 2, the surface acoustic wave element 2 has a wiring pattern 6 formed on the element substrate 2a, and the wiring pattern 7 extends from one bus bar of the IDT electrode 2b1. Thus, the wiring pattern 7 is formed so as to extend from the IDT electrode 2b1 toward the element electrode pad 3 around the functional body 2b. The wiring pattern 7 becomes an input / output path of an electric signal to the IDT electrode 2 b 1, and the element electrode pad 3 is provided on the wiring pattern 6 b and is electrically connected to the wiring pattern 6. That is, the wiring pattern 6 electrically connects the functional body 2 b and the element electrode pad 3.

  As shown in FIG. 1, the circuit wiring board 1 is disposed so as to oppose one main surface (lower surface) of the element substrate 2a, the substrate electrode pad 4 is provided on the surface (upper surface), and the lower surface conductor is provided on the lower surface. A layer 1c is provided, and an internal conductor layer 1b is provided inside. In the circuit wiring board 1, the substrate electrode pad 4 on the front surface (upper surface) and the internal conductor layer 1b are electrically connected through the through conductor layer 1a, and the internal conductor layer 1b and the lower conductor layer 1c are connected to each other. They are electrically connected through the through conductor layer 1a. The substrate electrode pad 4 has a thickness of, for example, 5 (μm) to 15 (μm).

  As shown in FIG. 1, the circuit wiring board 1 is formed in, for example, a generally thin rectangular parallelepiped shape. The circuit wiring board 1 is made of a ceramic material such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, a silicon carbide sintered body, or a glass ceramic sintered body. Alternatively, the circuit wiring board 1 is made of an organic resin material such as polyimide resin, cyanate resin, epoxy resin, or polyphenylene ether resin. A composite material obtained by mixing an inorganic material such as ceramic or glass with an organic resin material such as an epoxy resin can also be used. The circuit wiring board 1 has a long side and a short side in a plan view having a length of, for example, 30 (mm) to 300 (mm).

  Further, the substrate electrode pad 4 is formed with a nickel (Ni) layer and a gold (Au) layer thereon by using, for example, a plating layer forming method for the purpose of improving the bonding property with the solder bump 5. Has been.

  The circuit wiring board 1 can be manufactured using a manufacturing method similar to a general wiring board manufacturing method. An example of a method for manufacturing the circuit wiring board 1 is shown below. In the present embodiment, the circuit wiring board 1 is shown as having a two-layer structure including a first wiring board and a second wiring board. For example, the upper wiring board 1 and the lower wiring board 1 are shown. The second wiring board can be laminated and manufactured.

  In the circuit wiring board 1, first, the lower surface conductor layer 1c is formed of a metal material such as copper on the lower surface of the lower second wiring board by using a known printing method or photolithography method. In the second wiring board, a through-hole penetrating the second wiring board is formed on the lower conductor layer 1c from the upper surface by using laser processing, drilling, die processing, or the like. Next, the second wiring board is formed by using a well-known printing method or photolithography method, for example, with a through conductor layer 1a formed in a through hole with a metal material such as copper, and an inner conductor layer 1b on the upper surface. It is formed. Then, the first wiring board is laminated on the upper surface of the second wiring board, and the circuit wiring board 1 having two layers is obtained through the above manufacturing process.

  In the surface acoustic wave device 10, the element-side electrode pad 3 and the substrate-side electrode pad 4 are electrically joined via solder bumps 5.

  For example, a solder material to be the solder bump 5 is formed in advance on the element side electrode pad 3 or the substrate side electrode pad 4 by screen printing using a solder mask or the like. Then, the solder balls are formed by passing through an optimally controlled reflow furnace, and then cleaned. For example, when a solder ball is formed on the substrate-side electrode pad 4, the element-side electrode pad 3 of the surface acoustic wave element 2 is aligned with the solder ball, for example, a load is applied and it passes through a reflow furnace. Soldering. As a result, the element-side electrode pad 3 and the substrate-side electrode pad 4 are electrically joined via the solder bump 5, and the surface acoustic wave element 2 is mounted on the circuit wiring board 1.

  Further, for example, a solder material that becomes the solder bump 5 is formed in advance on the element side electrode pad 3 or the substrate side electrode pad 4 by screen printing using a solder mask or the like. For example, when a solder material is formed on the substrate side electrode pad 4, the solder material on which the element side electrode pad 3 of the surface acoustic wave element 2 is formed is aligned and brought into close contact with and optimally controlled. Soldered through a reflow oven and cleaned. As a result, the element-side electrode pad 3 and the substrate-side electrode pad 4 are electrically joined via the solder bump 5, and the surface acoustic wave element 2 is mounted on the circuit wiring board 1.

  The surface acoustic wave device 10 is provided so that the sealing resin 7 covers the upper surface of the surface acoustic wave element 2 (the main surface opposite to the one main surface of the element substrate 2a) and the side surface of the surface acoustic wave element 2. It is done. The thickness of the sealing resin 7 is, for example, 0.2 (mm) to 0.8 (mm).

  The first sealing resin 7a can be provided on the circuit wiring board 1 by using a screen printing method. The first sealing resin 7 a can be provided by pressure-bonding a sealing resin sheet previously formed in the shape of the first sealing resin 7 a on the circuit wiring board 1. Similarly, the second sealing resin 7b can be provided on the first sealing resin 7a by using a screen printing method. Moreover, the 2nd sealing resin 7b can be provided by crimping | bonding the sealing resin sheet previously formed in the shape of the 2nd sealing resin 7b on the 1st sealing resin 7a.

Further, the surface acoustic wave device 10B is configured by two surface acoustic wave elements 2 as shown in FIG. In the surface acoustic wave device 10 </ b> B, two surface acoustic wave elements 2 are separately provided on the circuit wiring board 1, and the two surface acoustic wave elements 2 respectively have solder bumps 5 on the circuit wiring board 1. Has been implemented through. As described above, the surface acoustic wave device 10 </ b> B may include two surface acoustic wave elements 2.

  Similar to the surface acoustic wave device 10, the surface acoustic wave device 10B is provided such that the lower surface 7ba of the second sealing resin 7b is positioned below the center X of the side surface 2d of the surface acoustic wave element 2. 2 sealing resin 7 b is bonded to the side surface 2 d of the surface acoustic wave element 2. The two surface acoustic wave elements 2 are provided with an interval of 10 (μm) to 150 (μm), for example. As described above, the surface acoustic wave device 10B includes the two surface acoustic wave elements 2. For example, one surface acoustic wave element 2 is a surface acoustic wave element for transmission, and the other surface acoustic wave element. Reference numeral 2 denotes a surface acoustic wave element for reception.

  FIG. 4B shows the positional relationship between the surface acoustic wave element 2 and the first sealing resin 7a in the surface acoustic wave device 10B. The first sealing resin 7 a is provided in a frame shape, surrounds the two surface acoustic wave elements 2, and the inner wall surface 7 aa is positioned in contact with the side surface 2 d of the surface acoustic wave element 2. The first sealing resin 7a is bonded to the side surface 2d of the surface acoustic wave element 2 facing the inner wall surface 7aa. Thus, as shown in FIG. 4, the surface acoustic wave device 10B is positioned such that the inner wall surface 7aa of the first sealing resin 7a is in contact with the three side surfaces 2d of the side surfaces 2d of the surface acoustic wave element 2. ing. The first sealing resin 7a is bonded to the three side surfaces 2d of the surface acoustic wave element 2 facing the inner wall surface 7aa.

  Similar to the surface acoustic wave device 10, the surface acoustic wave device 10 </ b> B can relieve the stress that pulls the surface acoustic wave element 2 upward, so that it can be relaxed between the element electrode pad 3 and the solder bump 5 or the substrate electrode pad 4. And peeling between the solder bumps 5 can be suppressed.

  The present invention is not limited to the surface acoustic wave device 10 and the surface acoustic wave device 10B described above, and various modifications and improvements can be made without departing from the scope of the present invention. Other embodiments will be described below. Note that, among the surface acoustic wave devices according to other embodiments, the same parts as those of the surface acoustic wave device 10 according to the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

<Embodiment 2>
A surface acoustic wave device 10A according to Embodiment 2 of the present invention will be described below with reference to FIG.

  The surface acoustic wave element 10A has a configuration as shown in FIG. 3, and the arrangement of the first sealing resin 7a and the second sealing resin 7b is different from that of the surface acoustic wave device 10. Are the same. In the first sealing resin 7a, the inner wall surface 7aa is located away from the side surface 2d of the surface acoustic wave element 2, and the second sealing resin 7b is formed from the side surface 2d of the surface acoustic wave element 2 and the inner wall surface 7aa. It is also provided between. The second sealing resin 7 b is provided over the side surface 2 d of the surface acoustic wave element 2.

  The second sealing resin 7b is also bonded to the side surface 2d of the surface acoustic wave element 2 facing the inner wall surface 7aa of the first sealing resin 7a. In other words, the first sealing resin 7a is provided away from the side surface 2d of the surface acoustic wave element 2, and the second sealing resin 7b is formed of the inner wall surface 7aa of the first sealing resin 7a and the elastic surface. It is provided so as to enter a gap between the wave element 2 and the side surface 2d, and is also bonded to the side surface 2d of the surface acoustic wave element 2 facing the inner wall surface 7aa of the first sealing resin 7a. In the first sealing resin 7 a, the inner wall surface 7 aa is located away from the side surface 2 d of the surface acoustic wave element 2, for example, by 5 (μm) to 100 (μm).

As shown in FIG. 3A, in the thickness direction of the surface acoustic wave element 2, the second sealing resin 7b
Is provided so that the lower surface 7ba is positioned below the center X of the side surface 2d of the element substrate 2a, has a smaller elastic modulus than the first sealing resin 7a, and the side surface 2d of the surface acoustic wave element 2 It is adhered to. Thus, in the thickness direction of the surface acoustic wave element 2, the second sealing resin 7b is provided such that the lower surface 7ba is positioned below the center X of the side surface 2d of the surface acoustic wave element 2. That is, the first sealing resin 7 a is provided such that the upper surface is located below the center X of the side surface 2 d of the surface acoustic wave element 2. As shown in FIG. 3, the distance H2 between the upper surface of the first sealing resin 7a and the center X of the side surface 2d of the element substrate 2a is, for example, 0 (μm) <H2 <200 (μm).

  In the surface acoustic wave device 10 </ b> A, the second sealing resin 7 b has a smaller elastic modulus than the first sealing resin 7 a, and the second sealing resin 7 b is the side surface 2 d of the surface acoustic wave element 2. The second sealing resin 7b further relaxes the stress that pulls up the surface acoustic wave element 2 that is generated when the sealing resin 7 thermally expands. be able to.

  Therefore, the surface acoustic wave device 10 </ b> A can relieve the stress that pulls the surface acoustic wave element 2 upward, so that it is between the element electrode pad 3 and the solder bump 5 or between the substrate electrode pad 4 and the solder bump 5. Can be further suppressed.

  As shown in FIG. 5, the surface acoustic wave device 10 </ b> C is provided with two surface acoustic wave elements 2 apart from each other on the circuit wiring board 1 in the same manner as the surface acoustic wave device 10 </ b> B. Two surface acoustic wave elements 2 are mounted on the substrate 1 via solder bumps. As described above, the surface acoustic wave device 10 </ b> C may be composed of the two surface acoustic wave elements 2.

  Similar to the surface acoustic wave device 10A, the surface acoustic wave device 10C is provided such that the lower surface 7ba of the second sealing resin 7b is positioned below the center X of the side surface 2d of the surface acoustic wave element 2. 2 sealing resin 7 b is bonded to the entire side surface 2 d of the surface acoustic wave element 2.

  FIG. 5B shows the positional relationship between the surface acoustic wave element 2 and the first sealing resin 7a in the surface acoustic wave device 10C. The first sealing resin 7a is provided in a frame shape, surrounds the surface acoustic wave element 2, and the inner wall surface 7aa is located away from the side surface 2d of the surface acoustic wave element 2, and the second sealing resin 7 b is also provided between the side surface 2 d of the surface acoustic wave element 2 and the inner wall surface 7 aa and is bonded to the side surface 2 d of the surface acoustic wave element 2. As described above, the second sealing resin 7 b is provided over the side surface 2 d of the surface acoustic wave element 2.

  In the surface acoustic wave device 10C, as shown in FIG. 5, the inner wall surface 7aa of the first sealing resin 7a is located away from the three side surfaces 2d of the side surfaces 2d of the surface acoustic wave element 2. The second sealing resin 7 b is bonded to the side surface 2 d of the surface acoustic wave element 2.

  The surface acoustic wave device 10C, like the surface acoustic wave device 10A, can further relieve the stress that pulls the surface acoustic wave element 2 upward, so that it is between the element electrode pad 3 and the solder bump 5 or the substrate electrode pad. Peeling between 4 and the solder bump 5 can be further suppressed.

  The present invention is not particularly limited to the above-described embodiments, and various changes and improvements can be made within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Circuit wiring board 1a Through-conductor layer 1b Inner conductor layer 1c Lower surface conductor layer 2 Surface acoustic wave element 2a Element board 2b Functional body 2c Protective film 2d Side surface 3 Element electrode pad 4 Substrate electrode pad 5 Solder bump 6 Wiring pattern 7 Sealing resin 7a First sealing resin 7aa Inner wall surface 7b Second sealing resin 7ba Lower surface 10, 10A, 10B, 10C Surface acoustic wave device S Opposite space

Claims (1)

A circuit wiring board;
A surface acoustic wave element mounted on the surface of the circuit wiring board via a solder bump with one main surface facing the surface,
A sealing resin that adheres to a side surface of the surface acoustic wave element and the circuit wiring board and seals a facing space between the surface of the circuit wiring board and the one main surface of the surface acoustic wave element. And
The sealing resin includes a frame-shaped first sealing resin provided on the circuit wiring board so as to surround the surface acoustic wave element, the other main surface of the surface acoustic wave element, and the first sealing. The second sealing resin is provided on the first sealing resin so as to cover the side surface of the surface acoustic wave element located above the stop resin, and has a smaller elastic modulus than that of the first sealing resin. Sealing resin,
In the first sealing resin, an inner wall surface is located away from the side surface of the surface acoustic wave element, and the second sealing resin is the first sealing resin in the thickness direction of the surface acoustic wave element. The lower surface facing the upper surface of the sealing resin is located below the center of the side surface of the surface acoustic wave element, and the side surface of the surface acoustic wave element and the inner wall surface of the first sealing resin A surface acoustic wave device which is also provided in between and is bonded to the side surface of the surface acoustic wave element.

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