JP2008219936A - Surface acoustic wave device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface acoustic wave device which prevents a sealing resin sealing a portion between a surface acoustic wave element and a mounting substrate from flowing into an exciting portion of the surface acoustic wave element. <P>SOLUTION: This surface acoustic wave device 1 has such a structure that the surface acoustic wave element 2 is connected to the mounting substrate 3 via a bump 4, and the sealing resin 5 seals the outer peripheral edge of the surface acoustic wave element 2, and secures a vibration space 7 between the exciting portion 6 of the surface acoustic wave element 2 and the mounting substrate 3. The surface acoustic wave element 2 is provided with an outside-resin-inflow-preventing barrier 9 surrounding the bump 4 and the exciting portion 6, and an inside-resin-inflow-preventing barrier 10 surrounding the exciting portion 6. A height h1 of the outside-resin-inflow-preventing barrier 9 is set to be smaller than a total height h4 of a height h2 of the bump 4 and a height h3 of an electrode land 8 formed on the mounting substrate 3, and a height h5 of the inside-resin-inflow-preventing barrier 10 is set to be smaller than the height h2 of the bump 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a surface acoustic wave device, and in particular, a technique for preventing a sealing resin sealing a surface acoustic wave element from a mounting substrate from flowing into the excitation portion of the surface acoustic wave element. About.

  Conventionally, as an example of the surface acoustic wave device, there is one disclosed in Patent Document 1 and having a structure showing a side section in FIG. That is, the surface acoustic wave device 51 has a configuration in which a surface acoustic wave element (SAW device chip) 52 and a mounting substrate 53 are integrated. The functional surface of the surface acoustic wave element 52 and the mounting substrate 53 are mounted. The surface is connected via a bump 54.

  Further, as shown in FIG. 22 illustrating the planar structure, an excitation portion 56 including a comb-shaped electrode portion (hereinafter referred to as IDT) is formed on the functional surface of the surface acoustic wave element 52. This excitation portion The outer peripheral edge of the surface acoustic wave element 52 in which the vibration space 57 is secured between the mounting surface 56 and the mounting surface of the mounting substrate 53 uses a sealing resin 58 that is a thermosetting resin such as an epoxy resin. It is sealed. At this time, electrode lands 59 for fixedly connecting the bumps 54 are formed on the mounting surface of the mounting substrate 53 as shown in FIG.

  In the surface acoustic wave device 51, the sealing resin 58 that seals between the surface acoustic wave element 52 and the mounting substrate 53 flows into the excitation unit 56 of the surface acoustic wave element 52. In order to prevent this, the inner and outer double resin inflow prevention weirs 61 and 62 are provided on the functional surface of the surface acoustic wave element 52 so as to have a height lower than the height of the bump 54 and to surround the excitation portion 56. Yes. That is, the resin inflow prevention weirs 61 and 62 here are formed of a photoresist and function as a weir for preventing the inflow of the sealing resin 58, and their height is set lower than the bump 54. The reason is that it is necessary to obtain a sufficient connection strength of the bumps 54 pressed at the time of face-down bonding of the surface acoustic wave element 52 to the mounting substrate 53, and between the resin inflow prevention weirs 61 and 62 and the mounting surface of the mounting substrate 53. This is to ensure a slight gap.

  In the surface acoustic wave device 51 having such a structure, the sealing resin 58 applied to seal the outer peripheral edge of the surface acoustic wave element 52 is connected to the outer resin inflow prevention weir 61 by the action of surface tension. It reaches the gap between the mounting board 53 and, in some cases, the gap between the inner resin inflow prevention weir 62 and the mounting board 53. However, since these gaps are narrow, the sealing resin 58 does not flow over the resin inflow prevention weirs 61 and 62, and the sealing resin 58 reaches the excitation portion 56 of the surface acoustic wave element 52. Inflow is prevented.

JP-A-8-316778

  However, in the conventional surface acoustic wave device 51, no consideration is given to the positional relationship between the resin inflow prevention weirs 61 and 62 and the bumps 54, and both of the resin inflow prevention weirs 61 and 62 are excited portions 56. It is only provided around. Therefore, each of the resin inflow prevention weirs 61 and 62 faces the electrode land 59 or faces the mounting surface itself of the mounting substrate 53 exposed without the electrode land 59 being formed. In such a case, the size of the gap that should be essentially uniform, that is, the separation interval between the resin inflow prevention weirs 61 and 62 and the mounting surface of the mounting substrate 53 becomes non-uniform.

  As a result, the sealing resin 58 flows over the resin inflow prevention weirs 61 and 62 even though the inner and outer double resin inflow prevention weirs 61 and 62 are provided on the functional surface of the surface acoustic wave element 52. This prevents the sealing resin 58 from flowing into and adhering to the excitation portion 56 of the surface acoustic wave element 52. If it becomes like this, it will be inevitable that the performance of the surface acoustic wave apparatus 51 will be reduced, and the defective product rate of the surface acoustic wave apparatus 51 will increase.

  The present invention was devised in view of these disadvantages, and it is ensured that the sealing resin that seals between the surface acoustic wave device and the mounting substrate flows into the excitation portion of the surface acoustic wave device. An object of the present invention is to provide a surface acoustic wave device that can be prevented.

A surface acoustic wave device according to the present invention includes a surface acoustic wave element having a functional surface including an excitation portion made of at least one IDT formed on a piezoelectric substrate, a mounting substrate, and a sealing resin. The surface acoustic wave element and the mounting substrate are connected via bumps so that the surface and the functional surface of the surface acoustic wave element face each other, and the outer peripheral edge of the surface acoustic wave element is sealed with a sealing resin A surface acoustic wave device in which a vibration space is ensured between the excitation portion of the surface acoustic wave element and the mounting surface of the mounting substrate, and the functional surface of the surface acoustic wave element includes bumps and A first outer resin inflow prevention weir arranged to surround the excitation unit; and a second outer resin inflow prevention weir arranged to surround the bump and the excitation unit inside the first outer resin inflow prevention weir. It is characterized by that.

Surface acoustic wave device of the present invention, because it has a first outer resin inlet dam and the second outer resin inlet dam, that damming the sealing resin in the first outer resin inlet dam Even if it is not possible, the sealing resin can be blocked by the second outer resin inflow prevention weir, and it is possible to prevent the occurrence of defects due to the sealing resin flowing into the excitation portion of the surface acoustic wave device. it can.

  At this time, the height of the first outer resin inflow prevention weir is preferably higher than that of the second outer resin inflow prevention weir. In particular, the height of the first outer resin inflow prevention weir is the height of the bump after the surface acoustic wave element and the mounting substrate are connected via the bump and the height of the electrode land formed on the mounting surface of the mounting substrate. And the height of the second outer resin inflow prevention weir is set to be lower than the height of the bump after the surface acoustic wave element and the mounting substrate are connected via the bump. Preferably it is.

  The first outer resin inflow prevention weir is preferably composed of at least two layers, and the lowermost layer of the first outer resin inflow prevention weir preferably has the same height as the second outer resin inflow prevention weir. In addition, at least the second outer resin inflow prevention weir may be formed using a material whose sealing resin has poorer wettability than the functional surface of the surface acoustic wave element and the mounting surface of the mounting substrate. preferable. At this time, it is preferable that the first outer resin inflow prevention weir has a step, and the step of the first outer resin inflow prevention weir is configured by at least one concave portion, or is configured by at least one convex portion. It is preferable that

The surface acoustic wave device of the present invention preferably further includes a substrate-side resin inflow prevention weir formed on the mounting substrate so as to face the outer resin inflow prevention weir. In particular, the total height of the outer resin inflow prevention weir and the substrate side resin inflow prevention weir is formed on the bump height and the mounting surface of the mounting substrate after the surface acoustic wave element and the mounting substrate are connected via the bump. It is preferable that the height is set lower than the total height of the electrode lands.

( Reference Example 1 )
1 is a side sectional view showing the structure of a surface acoustic wave device according to Reference Example 1 , FIG. 2 is a plan view showing the structure of a mounting substrate according to Reference Example 1 , and FIG. 3 is a surface acoustic wave according to Reference Example 1 . It is a top view which shows the structure of an element. 4 is a side sectional view showing the structure of the surface acoustic wave device according to the first modification, FIG. 5 is a side sectional view according to the second modification, and FIG. 6 is according to the third modification. It is a sectional side view. FIG. 7 is an explanatory diagram showing a manufacturing procedure of the surface acoustic wave device according to Reference Example 1 , and FIG. 8 is an explanatory diagram showing a manufacturing procedure of the surface acoustic wave device.

As shown in FIG. 1, the surface acoustic wave device 1 according to the reference example 1 has a functional surface of the surface acoustic wave element (SAW device chip) 2 and a mounting surface of the mounting substrate 3 arranged in an opposed state. The surface acoustic wave elements 2 are connected to each other through bumps 4 made of the above, and the outer peripheral edge of the surface acoustic wave element 2 is sealed with a sealing resin 5 which is a thermosetting resin such as an epoxy resin. The functional surface of the surface acoustic wave element 2, that is, the excitation unit 6 of the surface acoustic wave element 2 including an IDT, a reflector, and a wiring portion formed on the piezoelectric substrate, and the mounting substrate 3 including a dielectric such as alumina. A vibration space 7 necessary for exciting surface acoustic waves is secured between the mounting surface and the mounting surface. Note that, as shown in FIG. 2, electrode lands 8 for fixedly connecting the bumps 4 are formed on the mounting surface of the mounting substrate 3 after positioning. Note that the IDT, reflector, and wiring portion of the surface acoustic wave device 2 in FIG. 3 are omitted. Therefore, it may be different from this.

  On the other hand, on the functional surface of the surface acoustic wave element 2, a sealing resin 5 that seals between the surface acoustic wave element 2 and the mounting substrate 3 flows into the excitation unit 6 of the surface acoustic wave element 2. An outer resin inflow prevention weir 9 and an inner resin inflow prevention weir 10 are provided. That is, as shown in FIG. 3, the functional surface of the surface acoustic wave device 2 at this time is disposed at the outer peripheral position of the piezoelectric substrate surrounding both the bump 4 and the excitation unit 6 and has a rectangular frame shape in plan view. An outer resin inflow prevention weir 9 and an inner resin inflow prevention weir 10 having a rectangular frame shape in plan view, which is disposed at an inner peripheral position surrounding only the excitation unit 6, are provided. The outer resin inflow prevention weir 9 and the inner resin inflow prevention weir 10 may have rounded corners.

  The outer resin inflow prevention weir 9 and the inner resin inflow prevention weir 10 are materials having poor wettability with respect to the sealing resin 5 than the functional surface of the surface acoustic wave element 2 and the mounting surface of the mounting substrate 3, such as a photosensitive polyimide resin. , BCB (resin component: benzocyclobutene), Zcoat (resin component: cyclic polyosifine) and the like, and the outer resin inflow prevention weir 9 here includes the lower layer 9a It has a two-layer structure in which the upper layer 9b is laminated.

  The material used for the outer resin inflow prevention weir 9 and the inner resin inflow prevention weir 10 is preferably excellent in heat resistance against reflow when the surface acoustic wave device 1 is mounted on a printed board with solder. The temperature during reflow varies depending on the solder material used. For example, the reflow temperature of Sn—Pb eutectic solder is 180 ° C., and the reflow temperature of Sn—Ag—Cu solder is 220 ° C. Considering these, the outer resin inflow prevention weir 9 And the material used for the inner side resin inflow prevention weir 10 should just be able to endure the temperature of 260 degreeC.

  That is, the material forming the outer resin inflow prevention weir 9 and the inner resin inflow prevention weir 10 is required to have the following characteristics. First, it is heat resistance against reflow at the time of mounting with solder, and as described above, it is required that large deformation, decomposition, and outgassing at 260 ° C. do not occur. However, the deformation after sealing with the sealing resin 5 is not an essential requirement.

  Next, in order to prevent the inflow of the sealing resin 5, the surface of the surface acoustic wave element 2 with respect to the sealing resin 5 than the surface of the piezoelectric substrate, the surface of the mounting substrate 3, the electrode land 8 disposed on the mounting substrate 3, It is preferable that the wettability is poor. In addition, the dielectric constant is required to be low. When the dielectric constant is large, the electrical characteristics, in particular, the input capacity changes depending on the arrangement of the resin inflow prevention weirs 9 and 10, and as a result, the characteristics of the surface acoustic wave device 1 may be deteriorated. The dielectric constant of the piezoelectric substrate constituting the surface acoustic wave element 2 is desirably lower. Furthermore, after the resin inflow prevention weirs 9 and 10 are formed, it is necessary to have a hardness that does not cause deformation by the sealing resin 5. Furthermore, it is desirable that the hardness is low in order to eliminate the deformation of the surface acoustic wave caused by the difference in linear expansion coefficient between the surface acoustic wave element 2 and the mounting substrate 3.

  On the other hand, in order to cope with temperature changes, it is required to have a linear expansion coefficient comparable to that of the piezoelectric substrate of the surface acoustic wave element 2. For example, when the piezoelectric substrate is LiTaO 3, the linear expansion coefficient is about 15 ppm / ° C. in the surface acoustic wave propagation direction and about 7 ppm / ° C. in the direction perpendicular to the surface acoustic wave propagation direction. The linear expansion coefficient of the material forming 10 is preferably close to these. The linear expansion coefficient of the inner resin inflow prevention weir 10 is preferably smaller than the linear expansion coefficient of the bump 4 in order to prevent the inner resin inflow prevention weir 10 from coming into contact with the excitation unit 6.

  In addition, the piezoelectric substrate of the surface acoustic wave element 2 is required to have a material that can be formed with a constant height. That is, the minimum width of the resin inflow prevention weirs 9 and 10 is several tens of μm, and it is desirable that the resin is a photosensitive resin in order to form the resin accurately at a predetermined position. Furthermore, since the spacing becomes non-uniform when there is a undulation in the height direction, it is desirable that the material has few irregularities and a small particle size. Furthermore, after the resin inflow prevention weirs 9 and 10 are formed, for example, there are a cleaning process, a sealing resin coating process, and a heating process, so that these treatments can be withstood. It is required to have chemical resistance that can withstand the components.

  By the way, the height h1 of the outer resin inflow prevention weir 9 is a total height h4 (= h2 + h3) of the height h2 after the bump 4 is connected and the height h3 of the electrode land 8 formed on the mounting surface of the mounting substrate 3. ) (H1 <h4), and the height h5 of the inner resin inflow prevention weir 10 is set lower than the height h2 after the bump 4 is connected (h5 <h2). At this time, the height h1 of the outer resin inflow prevention weir 9 is higher than the total height h4 of the height h2 after the bump 4 is connected and the height h3 of the electrode land 8 formed on the mounting surface of the mounting substrate 3. Since it is set low, a slight gap S is secured between the outer resin inflow prevention weir 9 and the mounting surface of the mounting substrate 3.

  When the height h1 of the outer resin inflow prevention weir 9 is higher than the total height h4 of the height h2 after the bump 4 is connected and the height h3 of the electrode land 8 formed on the mounting surface of the mounting substrate 3. Since the bumps 4 cannot be pressed by the height (thickness) of the outer resin inflow prevention weir 9, sufficient connection strength when the mounting substrate 3 and the surface acoustic wave element 2 are mechanically connected is obtained. Absent. That is, in order to obtain sufficient connection strength of the bumps 4 pressed during the face-down bonding of the surface acoustic wave element 2 to the mounting substrate 3, the gap S between the outer resin inflow prevention weir 9 and the mounting surface of the mounting substrate 3. The height h1 of the outer resin inflow prevention weir 9 is the total height of the height h2 after the bump 4 is connected and the height h3 of the electrode land 8 formed on the mounting surface of the mounting substrate 3. In the present embodiment set lower than h4, sufficient connection strength can be obtained as a result of ensuring the gap S between the outer resin inflow prevention weir 9 and the mounting surface of the mounting substrate 3.

  The gap S between the outer resin inflow prevention weir 9 and the mounting surface of the mounting substrate 3 is preferably 0 to 15 μm. Further, when the height h5 of the inner resin inflow prevention weir 10 is set lower than the height h2 after the bump 4 is connected, the inner resin inflow prevention weir 10 is formed on the mounting surface of the mounting substrate 3 on the electrode land 8. Can be prevented. If the height h5 of the inner resin inflow prevention weir 10 is higher than the height h2 after the bump 4 is connected, the inner resin inflow prevention weir 10 can come into contact with the electrode land 8 of the mounting substrate 3, and the bump 4 can be pressed. Therefore, it is difficult to obtain a sufficient connection strength between the mounting substrate 3 and the surface acoustic wave element 2.

  Furthermore, by setting the width dimension of the inner resin inflow prevention weir 10 to be equal to or greater than the wetting amount of the sealing resin 5, the height h5 of the inner resin inflow prevention weir 10 can be lowered. Furthermore, when the outer resin inflow prevention weir 9 is formed by laminating the lower layer 9a and the upper layer 9b, the lower layer 9a may have the same height h5 as the inner resin inflow prevention weir 10. preferable. Thereby, the lower layer 9a of the outer resin inflow prevention weir 9 and the inner resin inflow prevention weir 10 can be formed in the same process, and the outer resin inflow prevention weir 9 is formed by the lower layer 9a and the upper layer 9b. Since it is formed in two steps, the outer resin inflow prevention weir 9 having a high aspect can be formed.

  In the surface acoustic wave device 1 according to the present embodiment, the outer resin inflow prevention weir 9 on the functional surface of the surface acoustic wave element 2 is provided at the outer peripheral position with respect to the bumps 4 and the above-described height relationship is adopted. As a result, the outer resin inflow prevention weir 9 faces the mounting surface of the mounting substrate 3, that is, the mounting surface exposed without forming the electrode land 8, and the outer resin inflow prevention weir 9 and the mounting substrate 3 are mounted. A gap S having a uniform separation interval of h4-h1 is secured between the surfaces. Therefore, even when the sealing resin 5 that seals the outer peripheral edge of the surface acoustic wave element 2 reaches the outer resin inflow prevention weir 9, the gap S between the outer resin inflow prevention weir 9 and the mounting surface of the mounting substrate 3 is uniform. Therefore, the sealing resin 5 does not flow into the outer resin inflow prevention weir 9 beyond the outer clearance.

  Even if the sealing resin 5 flows in over the outer resin inflow prevention weir 9, the inner resin inflow prevention weir 10 having a height h5 lower than the height h2 after the bump 4 is connected is provided. Since the surface acoustic wave element 2 is provided at the inner peripheral position surrounding the excitation unit 6, a small amount of the sealing resin 5 that has passed over the outer resin inflow prevention weir 9 passes over the inner resin inflow prevention weir 10 and the surface acoustic wave. Inflow to the excitation unit 6 of the element 2 is reliably prevented. Further, at this time, if the inner resin inflow prevention weir 10 is formed of a material having poor wettability with respect to the sealing resin 5, the outer resin inflow prevention weir 9 is difficult to prevent inflow in the sealing resin 5. It is possible to more reliably prevent the low molecular component from flowing along the functional surface of the surface acoustic wave device 2.

  In the present embodiment, the outer resin inflow prevention weir 9 is disposed so as to surround all of the bumps 4, and the inner resin inflow prevention weir 10 is disposed so as to surround only the excitation unit 6, but such a structure is used. However, the outer resin inflow prevention weir 9 may be disposed so as to surround a part of the bump 4 and the excitation portion 6, and the inner resin inflow prevention weir 10 may be disposed so as to surround at least the excitation portion 6. . That is, the outer resin inflow prevention weir 9 only needs to be disposed in a state of facing the mounting surface of the mounting substrate 3, and as a result, the outer resin inflow prevention weir 9 and the mounting surface of the mounting substrate 3 are evenly spaced. It is only necessary to ensure a gap S having an interval.

  The inner resin inflow prevention weir 10 here only needs to be able to prevent the sealing resin 5 beyond the outer resin inflow prevention weir 9 from flowing into the excitation unit 6 of the surface acoustic wave element 2, and at least the excitation unit. What is necessary is just to arrange | position so that 6 may be surrounded. In the present embodiment, the outer resin inflow prevention weir 9 and the inner resin inflow prevention weir 10 are formed using a material having poor wettability with respect to the sealing resin 5, both of which are the sealing resin. 5 does not need to have poor wettability. That is, since the material having poor wettability with respect to the sealing resin 5 is particularly effective in preventing the inflow of low molecular components in the sealing resin 5, the inflow of the sealing resin 5 can be reliably prevented. As long as the necessary inner resin inflow prevention weir 10 has poor wettability with respect to the sealing resin 5, the outer resin inflow prevention weir 9 may be formed of a more general photoresist material.

  Further, when the outer resin inflow prevention weir 9 formed on the functional surface of the surface acoustic wave element 2 is a laminate of the lower layer 9a and the upper layer 9b, the lower layer 9a is the surface acoustic wave element 2. It may be formed using the same metal material as that of the excitation portion 6, that is, IDT. However, there is no necessity that the outer resin inflow prevention weir 9 is laminated, and as shown in FIG. 4, the outer resin inflow prevention weir 9 is integrally formed with a height h1 from the beginning. Of course, it may be.

  Furthermore, in the present embodiment, as shown in FIG. 1, only the outer peripheral edge of the surface acoustic wave element 2 is sealed with the sealing resin 5, and the top surface of the surface acoustic wave element 2 is exposed to the outside. However, it is not limited to such a structure, and the top surface may be sealed with the sealing resin 5 as well as the outer peripheral edge of the surface acoustic wave element 2. It is desirable that the sealing resin 5 has a viscosity of 15 Pa · s to 150 Pa · s at the temperature at the time of application, and when having such a viscosity, it is possible to prevent inflow more reliably. Become. That is, if the viscosity of the sealing resin 5 is small, it is easy to flow in, and if the viscosity is large, bubbles that deteriorate sealing properties are likely to enter. Therefore, the lower limit of the viscosity is due to the flow into the excitation unit 6 and the upper limit is the bubble. It is defined by the occurrence of

  By the way, in the present embodiment, it is possible to adopt the following modifications. First, as shown in FIG. 5, a groove (concave portion) 9c having a predetermined width is formed in the outer resin inflow prevention weir 9 provided on the functional surface of the surface acoustic wave element 2, thereby forming a step in the outer resin inflow prevention weir 9. May be formed. In this way, even if the outer corner end portion of the outer resin inflow prevention weir 9 cannot block the inflow of the sealing resin 5, the inner corner end portion can block the inflow of the sealing resin 5. It becomes. The same effect can be obtained by forming a convex portion on the outer resin inflow prevention weir 9 to provide a step.

  In addition, as shown in FIG. 6, the outer resin inflow prevention weir 9 and the inner resin inflow prevention weir 10 are arranged outside and adjacent to the outer resin inflow prevention weir (first outer resin inflow prevention weir) 9. A resin inflow prevention weir (second outer resin inflow prevention weir) 11 may be provided. With such a structure, even if the outer resin inflow prevention weir (first outer resin inflow prevention weir) 9 cannot block the inflow of the sealing resin 5, the outer resin inflow prevention weir (second outer resin inflow weir) The prevention weir) 11 can prevent the sealing resin 5 from flowing in.

  Further, although not shown, a groove having a predetermined width may be formed in the inner resin inflow prevention weir 10. In such a structure, the size of the inner resin inflow prevention weir 10 is not changed. However, the distance between the inner resin inflow prevention weir 10 and the excitation unit 6 is increased, and the sealing resin 5 does not flow into the excitation unit 6. Further, the second inner resin inflow prevention weir (first inner resin inflow prevention weir) 10 may be provided adjacent to the inner resin inflow prevention weir (first inner resin inflow prevention weir) 10, and if such a structure is adopted, Since the distance between the inner resin inflow prevention weir (first inner resin inflow prevention weir) 10 and the excitation unit 6 is further increased by the second inner resin inflow prevention weir, the inflow of the sealing resin 5 to the excitation unit 6 is prevented. It can be surely stopped.

  Furthermore, in this case, the second inner resin inflow prevention weir has the same height as the inner resin inflow prevention weir (first inner resin inflow prevention weir) 10, and this second inner resin inflow prevention weir It is preferable that the prevention weir is formed using the same material as the inner resin inflow prevention weir (first inner resin inflow prevention weir) 10. That is, with such a structure, the second inner resin inflow prevention weir (first inner resin inflow prevention weir) 10 can be formed simultaneously.

  Next, a method for manufacturing the surface acoustic wave device 1 and the surface acoustic wave element 2 according to the present embodiment will be briefly described with reference to FIGS.

  First, as shown in FIG. 7 illustrating the manufacturing procedure of the surface acoustic wave element, a piezoelectric element in which a plurality of bumps 4 and excitation portions 6 (not shown) are formed by dicing to form a large number of surface acoustic wave elements 2. A substrate 12 (LiTaO3 wafer) is prepared, and an outer resin inflow prevention weir 9 and an inner resin inflow prevention weir 10 are respectively formed for each surface acoustic wave element region 13 in which bumps 4 and excitation parts 6 have been formed. The piezoelectric substrate 12 may be a substrate made of another material such as LiNbO3 instead of LiTaO3.

  Further, it is possible to use a piezoelectric substrate 12 in which a piezoelectric thin film such as ZnO is formed on the surface of a dielectric substrate. Furthermore, in the above description, the outer resin inflow prevention weir 9 and the inner resin inflow prevention weir 10 are formed in the surface acoustic wave element region 13 where the bumps 4 are formed. The procedure of forming the bumps 4 after forming the prevention weir 10 may be used.

  That is, here, under the outer resin inflow prevention weir 9 disposed around the bump 4 and the excitation unit 6 on the LiTaO3 wafer which is the piezoelectric substrate 12 on which the excitation unit 6 made of IDT or reflector is formed. The side layer 9a and the inner resin inflow prevention weir 10 disposed so as to surround only the excitation unit 6 are photosensitive while taking care that their height h5 is lower than the height h2 after the bump 4 is connected. Simultaneous formation by a photoresist method using polyimide resin or the like is performed. Subsequently, the upper layer 9b is formed on the lower layer 9a of the outer resin inflow prevention weir 9 while the height h1-h5 is higher than the height h3 of the electrode land 8 formed on the mounting surface of the mounting substrate 3. It is formed by stacking.

  As a result, the surface acoustic wave element region 13 of the piezoelectric substrate 12 has a height h1 and an outer resin inflow prevention weir 9 that surrounds the bump 4 and the excitation portion 6, and a height h5, and then the excitation portion 6 The inner resin inflow prevention weir 10 that surrounds only the inner and outer double layers is formed. Thereafter, when the LiTaO3 wafer as the piezoelectric substrate 12 is diced to a chip size, individual surface acoustic wave elements 2 corresponding to the respective surface acoustic wave element regions 13 are produced.

  By the way, an outer resin inflow prevention weir (first outer resin inflow prevention weir) 9 and an inner resin inflow prevention weir 10 provided on the functional surface of the surface acoustic wave element 2 are provided. When the outer resin inflow prevention weir (11) is provided, or when the second inner resin inflow prevention weir (first inner resin inflow prevention weir) 10 is provided at the inner position of the inner resin inflow prevention weir (first inner resin inflow prevention weir) 10, The outer resin inflow prevention weir (second outer resin inflow prevention weir) 11 and the second inner resin inflow prevention weir are used as the outer resin inflow prevention weir (first outer resin for each surface acoustic wave element region 13 in FIG. Inflow prevention weir) 9 and inner resin inflow prevention weir (first inner resin inflow prevention weir) 10 are formed.

  Further, an electrode land 8 is formed in advance in each region corresponding to each of the surface acoustic wave elements 2, that is, in each element corresponding region 14, and a collective substrate 15 to be a mounting substrate 3 later is prepared, as shown in FIG. Each of the diced surface acoustic wave elements 2 is mounted on each element corresponding region 14 of the collective substrate 15 by face-down bonding. Thereafter, although not shown in the figure, when the sealing resin 5 is applied to the outer periphery of each of the surface acoustic wave elements 2 mounted on the collective substrate 15 and cured, the collective substrate 15 is diced into chips. Thus, the surface acoustic wave device 1 having the structure shown in FIG.

( Reference Example 2 )
9 is a side sectional view showing the structure of the surface acoustic wave device according to Reference Example 2 , FIG. 10 is a plan view showing the structure of the surface acoustic wave device, and FIG. 11 is a plan view showing the structure of the mounting substrate. FIG. 12 is an explanatory diagram showing a manufacturing procedure of the surface acoustic wave device according to Reference Example 2 , and FIG. 13 is an explanatory diagram showing a manufacturing procedure of the surface acoustic wave device. Since the overall structure of the surface acoustic wave device according to the reference example 2 is not fundamentally different from that of the reference example 1 , in FIGS. The detailed explanation here is omitted.

As shown in FIG. 9, the surface acoustic wave device 21 according to the reference example 2 has a functional surface of a surface acoustic wave element (SAW device chip) 2 connected to a mounting surface of a mounting substrate 3 via bumps 4. In other words, only the outer peripheral edge of the surface acoustic wave element 2 is sealed with the sealing resin 5. And the excitation part 6 formed in the functional surface of the surface acoustic wave element 2, ie, the excitation part 6 of the surface acoustic wave element 2 which is IDT, a reflector, and a wiring part, and the mounting substrate 3 which consists of dielectrics, such as an alumina. A vibration space 7 is secured between the mounting surface and the mounting surface. In addition, IDT of the surface acoustic wave element 2 in FIG. 10, a reflector, and the wiring part are abbreviate | omitted. Therefore, it may be different from this.

  Further, as shown in the plan view of FIG. 10, the functional surface of the surface acoustic wave element 2 has a sealing resin 5 that seals between the surface acoustic wave element 2 and the mounting substrate 3, for example, an epoxy resin. An outer resin inflow prevention weir 22 and an inner resin inflow prevention weir 23 for preventing the sealing resin 5 from flowing into the excitation portion 6 of the surface acoustic wave element 2 are provided in an inner and outer double. . That is, on the functional surface of the surface acoustic wave element 2, an outer resin inflow prevention weir 22 having a rectangular frame shape in plan view, which is disposed at an outer peripheral position surrounding the bump 4 and the excitation portion 6, and an inner portion surrounding only the excitation portion 6. An inner resin inflow prevention weir 23 having a rectangular frame shape in plan view is provided at the circumferential position. The height of the outer resin inflow prevention weir 22 is the same as the height h5 of the inner resin inflow prevention weir 23, and is set lower than the height h2 after the bump 4 is connected (h5 <h2).

  On the other hand, as shown in the plan view of FIG. 11, electrode lands 8 for fixedly connecting the bumps 4 are positioned and formed on the mounting surface of the mounting substrate 3. A substrate-side resin inflow prevention weir 24 arranged so as to surround the bump 4 and the excitation unit 6 formed on the surface is formed at a position facing the outer resin inflow prevention weir 22 formed in the surface acoustic wave element 2. . Further, at this time, the height h6 of the substrate side resin inflow prevention weir 24 is the sum of the height h7 (= h5 + h6) with the height h5 of the outer resin inflow prevention weir 22 and the height h2 after the bump 4 is connected. The height is set to be lower than the total height h4 (= h2 + h3) with the height h3 of the electrode land 8 formed on the mounting surface of the substrate 3.

  Since the outer resin inflow prevention weir 22 and the inner resin inflow prevention weir 23 and the substrate side resin inflow prevention weir 24 are in the height relationship as described above, the outer resin formed on the functional surface of the surface acoustic wave element 2. Between the inflow prevention weir 22 and the substrate-side resin inflow prevention weir 24 formed on the mounting surface of the mounting substrate 3, a gap S having a uniform separation distance h4-h7 is secured. As a result, even when the bump 4 is pressed during face-down bonding of the surface acoustic wave element 2 to the mounting substrate 3, the outer resin inflow prevention weir 22 and the substrate side resin inflow prevention weir 24 which are formed to face each other come into contact with each other. Thus, sufficient connection strength of the bumps 4 can be obtained.

  In the surface acoustic wave device 21, even when the sealing resin 5 sealing the outer peripheral edge of the surface acoustic wave element 2 reaches the outer resin inflow prevention weir 22 and the substrate side resin inflow prevention weir 24, the outer resin inflow prevention is achieved. Since the gap S between the weir 22 and the substrate-side resin inflow prevention weir 24 is uniform, the sealing resin 5 does not flow into beyond the outer resin inflow prevention weir 22 and the substrate-side resin inflow prevention weir 24. Even if the sealing resin 5 flows in beyond the outer resin inflow prevention weir 22 and the substrate side resin inflow prevention weir 24, the inner resin inflow prevention weir 23 causes the excitation unit 6 of the surface acoustic wave element 2 to be excited. Since it surrounds, it is reliably prevented that a small amount of the sealing resin 5 that has passed over the outer resin inflow prevention weir 22 reaches the excitation unit 6.

  The gap S between the outer resin inflow prevention weir 22 and the mounting surface of the mounting substrate 3 is preferably 0 to 15 μm. In other words, the outer resin inflow prevention weir 22 and the mounting substrate 3 may partially contact each other due to the swell and inclination on the mounting substrate 3, but the average interval of the gap S is set to the above value. It becomes possible to prevent the sealing resin 5 from flowing in.

In addition, at least the inner resin inflow prevention weir 23 among the outer resin inflow prevention weir 22, the inner resin inflow prevention weir 23, and the substrate side resin inflow prevention weir 24 is similar to the reference example 1 in that the functional surface of the surface acoustic wave element 2 and It is preferable to use a material having poorer wettability with respect to the sealing resin 5 than the mounting surface of the mounting substrate 3, such as a photosensitive polyimide resin. With such a configuration, the low molecular component in the sealing resin 5, which was difficult to prevent the inflow by the outer resin inflow prevention weir 22 and the substrate side resin inflow prevention weir 24, It is possible to more reliably prevent inflow through the functional surface.

  The material having poor wettability with respect to the sealing resin 5 is effective for preventing the inflow of low molecular components in the sealing resin 5, and the inner resin inflow prevention weir 23 required to prevent the inflow of the sealing resin 5 is provided. As long as the wettability with respect to the sealing resin 5 is poor, the outer resin inflow prevention weir 22 and the substrate side resin inflow prevention weir 24 do not necessarily need to have poor wettability with respect to the sealing resin 5. Therefore, if the inner resin inflow prevention weir 23 that is required to reliably prevent the inflow of the sealing resin 5 is poor in wettability with respect to the sealing resin 5, the material for forming the outer resin inflow prevention weir 22 is It may be a more general photoresist material. Furthermore, it is needless to say that the materials forming the outer resin inflow prevention weir 22, the inner resin inflow prevention weir 23, and the substrate side resin inflow prevention weir 24 are also excellent in reflow heat resistance (260 ° C.).

By the way, although not shown in the drawings, the same modification example as in the reference example 1 can be adopted in the reference example 2 . That is, the outer resin inflow prevention weir 22 provided on the functional surface of the surface acoustic wave element 2 is disposed so as to surround a part of the bump 4 and the excitation unit 6, and the inner resin inflow prevention weir 23 at least includes the excitation unit 6. It may be one that is surrounded. Further, a groove is formed in each of the outer resin inflow prevention weir 22 and the inner resin inflow prevention weir 23, or a second outer resin inflow prevention weir 23 is provided between the outer resin inflow prevention weir 22 and the inner resin inflow prevention weir 23. Furthermore, a second inner resin inflow prevention weir may be provided at an inner position of the inner resin inflow prevention weir 23.

  Next, a method for manufacturing the surface acoustic wave device 21 and the surface acoustic wave element 2 according to the present embodiment will be briefly described with reference to FIGS.

  First, as shown in FIG. 12 illustrating the manufacturing procedure of the surface acoustic wave device, the piezoelectric substrate 12 on which a plurality of bumps 4 and excitation portions 6 (not shown) that are diced into a plurality of surface acoustic wave devices 2 are formed. (LiTaO3 wafer) is prepared, and the outer resin inflow prevention weir 22 and the inner resin inflow prevention weir 23 are formed for each surface acoustic wave element region 13 in which the bumps 4 and the excitation portions 6 are formed. The piezoelectric substrate 12 may be a substrate made of other materials such as LiNbO3 as well as LiTaO3.

  Although the piezoelectric substrate 12 is used here, a substrate in which a piezoelectric thin film such as ZnO is formed on the surface of a dielectric substrate can be used in place of the piezoelectric substrate 12. Further, although the outer resin inflow prevention weir 22 and the inner resin inflow prevention weir 23 are formed in the surface acoustic wave element region 13 where the bumps 4 are formed, the outer resin inflow prevention weir 22 and the inner resin inflow prevention weir 23 are formed. After that, the procedure for forming the bumps 4 may be used.

  That is, at this time, the outer resin inflow prevention weir 22 is disposed so as to surround the bump 4 and the excitation unit 6 on the LiTaO3 wafer, which is the piezoelectric substrate 12 on which the excitation unit 6 made of IDT, reflector, or the like is formed. And the inner resin inflow prevention weir 23 arranged so as to surround only the excitation unit 6 while taking care that the height h5 of both of them is lower than the height h2 after the bump 4 is connected. Simultaneous formation by a photoresist method using a resin or the like is performed.

  Subsequently, the LiTaO3 wafer as the piezoelectric substrate 12 is diced into chip sizes, and individual surface acoustic wave elements 2 corresponding to the surface acoustic wave element regions 13 are produced. On the other hand, an electrode land 8 is formed in advance in each region corresponding to each of the surface acoustic wave elements 2, that is, in each element corresponding region 14, and a collective substrate 15 to be a mounting substrate 3 later is prepared. In addition, the substrate-side resin is positioned at a position facing the outer resin inflow prevention weir 22 in each element corresponding region 14 of the prepared collective substrate 15, that is, a position facing the outer resin inflow prevention weir 22 formed in the surface acoustic wave element 2. An inflow prevention weir 24 is formed.

  Thereafter, each of the diced surface acoustic wave elements 2 is mounted on each element corresponding region 14 of the collective substrate 15 by face-down bonding. Further, although not shown in the figure, the sealing resin 5 is applied to the outer periphery of each surface acoustic wave element 2 mounted on the collective substrate 15 and cured, and then the collective substrate 15 is diced to a chip size. Then, the surface acoustic wave device 21 having the structure shown in FIG. 9 is produced.

( Reference Example 3 )
Figure 14 is a side sectional view showing the structure of a surface acoustic wave device according to Example 3, FIG. 15 is a plan view showing the structure of a surface acoustic wave device, FIG. 16 is a surface acoustic wave according to a modification of Reference Example 3 It is a sectional side view which shows the structure of an apparatus. The overall structure of the surface acoustic wave device according to Reference Example 3 is not fundamentally different from that of Reference Example 1, and therefore, in FIGS. Reference numerals are assigned, and detailed description thereof is omitted here.

As shown in FIG. 14, the surface acoustic wave device 31 according to the reference example 3 is one in which the functional surface of the surface acoustic wave element (SAW device chip) 2 is connected to the mounting surface of the mounting substrate 3 via bumps 4. In other words, the outer peripheral edge and the top surface of the surface acoustic wave element 2 are sealed with a sealing resin 5. And the excitation part 6 formed in the functional surface of the surface acoustic wave element 2, ie, the excitation part 6 of the surface acoustic wave element 2 which consists of IDT, a reflector, and a wiring part, and the mounting substrate 3 which consists of dielectrics, such as an alumina. A vibration space 7 is secured between the mounting surface and the mounting surface. Note that the IDT, reflector, and wiring portion of the surface acoustic wave element 2 in FIG. 15 are omitted. Therefore, it may be different from this.

  On the other hand, as shown in FIG. 14, electrode lands 8 for fixedly connecting the bumps 4 are formed on the mounting surface of the mounting substrate 3 by positioning. Further, as shown in the plan view of FIG. 15, the functional surface of the surface acoustic wave element 2 has a sealing resin 5 that seals between the surface acoustic wave element 2 and the mounting substrate 3, for example, an epoxy resin. An outer resin inflow prevention weir 32 for preventing the sealing resin 5 from flowing into the excitation unit 6 of the surface acoustic wave element 2 is provided. That is, the functional surface of the surface acoustic wave element 2 is provided with an outer resin inflow prevention weir 32 having a rectangular frame shape in plan view, which is disposed at an outer peripheral position surrounding the bump 4 and the excitation unit 6.

  This outer resin inflow prevention weir 32 is made of a material having poorer wettability with respect to the sealing resin 5 than the functional surface of the surface acoustic wave element 2 and the mounting surface of the mounting substrate 3, such as photosensitive polyimide resin or BCB (resin component: It is formed by a photoresist method using benzocyclobutene), Zcoat (resin component: cyclic polyosifine) or the like. The material used for the outer resin inflow prevention weir 32 is preferably excellent in heat resistance against reflow when the surface acoustic wave device 1 is mounted on a printed board with solder.

  Note that the temperature during reflow varies depending on the solder material used. For example, the reflow temperature of Sn—Pb eutectic solder is 180 ° C., and the reflow temperature of Sn—Ag—Cu solder is 220 ° C. Considering these points, it is used for the outer resin inflow prevention weir 32. The material to be used only needs to withstand a temperature of 260 ° C. Further, the outer resin inflow prevention weir 32 at this time has a structure in which a lower layer 32a and an upper layer 32b are laminated as shown in FIG. With such a configuration, since the upper layer 32b can be formed on the lower layer 32a, it is possible to form a weir with a high aspect ratio as compared with a single layer.

  Further, the outer resin inflow prevention weir 32 is set to be lower than the combined height of the bump 4 after connection and the height of the electrode land. Since the outer resin inflow prevention weir 32 has the height as described above, between the outer resin inflow prevention weir 32 formed on the functional surface of the surface acoustic wave element 2 and the mounting surface of the mounting substrate 3, A gap S having a uniform spacing is ensured. As a result, even when the bumps 4 are pressed during the face-down bonding of the surface acoustic wave element 2 to the mounting substrate 3, the outer resin inflow prevention weirs 32 formed to face each other do not come into contact with the mounting substrate 3, It is possible to obtain a sufficient connection strength of the bump 4.

  In the surface acoustic wave device 31, even when the sealing resin 5 sealing the outer peripheral edge of the surface acoustic wave element 2 reaches the outer resin inflow prevention weir 32, the outer resin inflow prevention weir 32, the mounting substrate 3, Since the gap S is uniform, the sealing resin 5 does not flow until it exceeds the outer resin inflow prevention weir 32. The gap S between the outer resin inflow prevention weir 32 and the mounting surface of the mounting substrate 3 is preferably about 0 to 15 μm.

  Incidentally, as shown in FIGS. 14 and 15, the outer resin inflow prevention weir 32 in the present embodiment has a groove (recess) 32c having a predetermined width, and as a result of having this groove 32c, the outer resin inflow prevention is provided. The weir 32 has a step. Therefore, even if the outer corner end portion of the outer resin inflow prevention weir 32 cannot block the sealing resin inflow, the inner corner end portion can block the sealing resin inflow.

  That is, since there is a step formed by the groove 32c in the outer resin inflow prevention weir 32, the principle that the inflow of the sealing resin 5 can be prevented is as follows. First, the sealing resin 5 is applied from the direction of the outer peripheral edge of the surface acoustic wave element 2, but when there is no step in the outer resin inflow prevention weir 32, the sealing beyond the corner end portion of the outer resin inflow prevention weir 32 is performed. The resin 5 may reach the excitation unit 6 as it is. On the other hand, when there is a step in the outer resin inflow prevention weir 32, even if the sealing resin 5 exceeds the corner end portion of the outer resin inflow prevention weir 32, the sealing resin 5 over the outer resin inflow prevention weir 32. Reaches the bottom of the groove 32, which is a step.

  Then, the corner end of the step acts, and the sealing resin 5 is more easily transmitted in the step direction than in the direction toward the excitation unit 6 due to the surface tension. That is, the sealing resin 5 is transmitted not in the direction toward the excitation unit 6 but in the direction in which the groove 32c extends. Therefore, if the outer resin inflow prevention weir 32 having a step is provided, the inflow of the sealing resin 5 can be more reliably prevented. In addition, as shown in FIG. 16, even if a step is provided by forming a convex portion on the outer resin inflow prevention weir 32, the same effect can be obtained. At this time, the step does not necessarily have to be a right angle, and may have a skirt or a taper angle generated in the process.

  Also in the present embodiment, as in the second embodiment, the substrate-side resin inflow prevention weir may of course be provided at a position facing the outer resin inflow prevention weir 32 on the mounting substrate 3. It is. Further, the total height of the outer resin inflow prevention weir 32 and the substrate side resin inflow prevention weir is equal to the height of the bump 4 after the surface acoustic wave element 2 and the mounting substrate 3 are connected via the bump 4 and the mounting substrate 3. It is preferable that the height is set lower than the total height of the electrode lands 8 formed on the mounting surface.

( Embodiment )
Figure 17 is a side sectional view showing the structure of a surface acoustic wave device according to the embodiment, FIG. 18 is a plan view showing the structure of a surface acoustic wave device, a surface acoustic 19 according to the first modification of the embodiment FIG. 20 is a side sectional view showing the structure of a surface acoustic wave device according to a second modification of the embodiment . Since the overall structure of the surface acoustic wave device according to the embodiment is not fundamentally different from that of Reference Example 1 , the same reference numerals are used in FIGS. 17 to 20 for parts and portions that are the same as or equivalent to those of FIGS. A detailed description is omitted here.

As shown in FIG. 17, the surface acoustic wave device 41 according to the embodiment has a functional surface of a surface acoustic wave element (SAW device chip) 2 connected to a mounting surface of a mounting substrate 3 via bumps 4. In other words, the outer peripheral edge and the top surface of the surface acoustic wave element 2 are sealed with the sealing resin 5. The excitation portion 6 formed on the functional surface of the surface acoustic wave element 2, that is, the excitation portion 6 of the surface acoustic wave element 2 that is an IDT, reflector, wiring portion, or pad portion, and a dielectric such as alumina. A vibration space 7 is secured between the mounting surface of the mounting substrate 3. The surface acoustic wave element 2 is not limited to one in which two IDTs are cascade-connected in two stages.

  On the mounting surface of the mounting substrate 3, as shown in FIG. 17, electrode lands 8 for fixedly connecting the bumps 4 are positioned and formed. Further, as shown in the plan view of FIG. 18, the functional surface of the surface acoustic wave element 2 is a sealing resin 5 that seals between the surface acoustic wave element 2 and the mounting substrate 3, such as an epoxy resin. The first outer resin inflow prevention weir 42 and the second outer resin inflow prevention weir 43 for preventing the sealing resin 5 such as the like from flowing into the excitation unit 6 of the surface acoustic wave element 2 are provided. It is provided with double inside and outside. That is, the functional surface of the surface acoustic wave element 2 includes a first outer resin inflow prevention weir 42 having a rectangular frame shape in plan view and disposed at an outer peripheral position surrounding the bump 4 and the excitation unit 6, and a first outer side. A second outer resin inflow prevention weir 43 having a rectangular frame shape in plan view and disposed at the inner peripheral position of the resin inflow prevention weir 42 is provided. The first outer resin inflow prevention weir 42 and the second outer resin inflow prevention weir 43 may have rounded corners.

  Therefore, in the surface acoustic wave device 41, even if the sealing resin 5 that seals the outer peripheral edge of the surface acoustic wave element 2 flows in over the first outer resin inflow prevention weir 42, The second outer resin inflow prevention weir 43 is provided at the inner peripheral position of the first outer resin inflow prevention weir 42 so as to surround the bump 4 and the excitation unit 6. It is possible to prevent the low molecular component of the encapsulating resin 5 that has exceeded from flowing into the excitation unit 6. In the surface acoustic wave element 2, a protective film made of SiO2 or the like may be formed on the surface.

  At this time, the first outer resin inflow prevention weir 42 and the second outer resin inflow prevention weir 43 have poorer wettability with respect to the sealing resin 5 than the functional surface of the surface acoustic wave element 2 and the mounting surface of the mounting substrate 3. It is formed by a photoresist method using a material such as photosensitive polyimide resin, BCB (resin component: benzocyclobutene), Zcoat (resin component: cyclic polyolefin). The material used to form the first outer resin inflow prevention weir 42 and the second outer resin inflow prevention weir 43 is heat resistant to reflow when the surface acoustic wave device 1 is mounted on a printed board with solder. It is desirable to have excellent properties.

  However, the temperature during reflow varies depending on the solder material used. For example, the reflow temperature of Sn—Pb eutectic solder is 180 ° C., and the reflow temperature of Sn—Ag—Cu solder is 220 ° C. Considering these, it is used for the outer resin inflow prevention weir 32. Any material that can withstand a temperature of 260 ° C. is acceptable.

  Further, as shown in FIG. 17, the first outer resin inflow prevention weir 42 has a two-layer structure in which a lower layer 42a and an upper layer 42b are laminated. With this configuration, since the upper layer 42b can be formed on the lower layer 42a, it is possible to form a weir with a higher aspect ratio than a single layer. Furthermore, the lower layer 42a of the first outer resin inflow prevention weir 42 and the second outer resin inflow prevention weir 43 have the same height. Therefore, the lower layer 42a of the first outer resin inflow prevention weir 42 and the second outer resin inflow prevention weir 43 can be formed by the same process.

  On the other hand, the second outer resin inflow prevention weir 43 is set to be lower than the height of the first outer resin inflow prevention weir 42, and the first outer resin inflow prevention weir 42 is higher than the bump 4 after connection. And the height of the electrode land is set lower than the total height. Since the first outer resin inflow prevention weir 42 and the second outer resin inflow prevention weir 43 are as described above, the first outer resin inflow formed on the functional surface of the surface acoustic wave device 2 is used. A gap S having a uniform separation interval is secured between the prevention weir 42 and the mounting surface of the mounting substrate 3.

  As a result, the first outer resin inflow prevention weir 42 and the second outer resin inflow prevention weir 42 formed to face each other even if the bump 4 is pressed during face-down bonding of the surface acoustic wave element 2 to the mounting substrate 3. 43 does not come into contact with the mounting substrate 3 and sufficient connection strength of the bumps 4 can be obtained. Accordingly, in the surface acoustic wave device 41, even if the sealing resin 5 sealing the outer peripheral edge of the surface acoustic wave element 2 may reach the first outer resin inflow prevention weir 42, the first outer side Since the gap S between the resin inflow prevention weir 42 and the mounting substrate 3 is uniform, the sealing resin 5 does not flow in until it exceeds the first outer resin inflow prevention weir 42.

  In addition, it is desirable that the separation interval of the gap S between the first outer resin inflow prevention weir 42 and the mounting surface of the mounting substrate 3 is 0 to 15 μm.

  Further, as shown in FIGS. 17 and 18, a groove (recess) 42 c having a predetermined width is formed in the first outer resin inflow prevention weir 42. As a result of the formation of the groove 42c, the first outer resin inflow prevention weir 42 has a step, and the sealing resin is formed at the outer corner end portion of the first outer resin inflow prevention weir 42. Even if the inflow of the sealing resin 5 cannot be prevented, the inflow of the sealing resin 5 can be reliably prevented by the corner end portion located inside thereof.

  Here, the principle that the inflow of the sealing resin 5 can be prevented by the step formed by the groove 42c formed in the first outer resin inflow prevention weir 42 will be described. First, the sealing resin 5 is applied from the direction of the outer peripheral edge of the surface acoustic wave element 2, but when there is no step in the first outer resin inflow prevention weir 42, the corner end of the first outer resin inflow prevention weir 42. The sealing resin 5 exceeding the portion may reach the excitation portion 6 as it is. However, when there is a step in the first outer resin inflow prevention weir 42, the first outer resin inflow prevention weir 42 is placed where the sealing resin 5 exceeds the corner end portion of the first outer resin inflow prevention weir 42. The overlying sealing resin 5 reaches the bottom of the groove 42c, which is a step.

  Therefore, the corner end portion of the step acts, and the sealing resin 5 is more easily transmitted through the step than the direction toward the excitation unit 6 based on the relationship of the surface tension. That is, the sealing resin 5 is transmitted along the direction in which the groove 42c extends, not in the direction toward the excitation unit 6. Therefore, it is possible to prevent the sealing resin 5 from flowing by providing the outer resin inflow prevention weir 42 having a step. In addition, as shown in FIG. 19, the same effect can be acquired also by providing a level | step difference by forming a convex part in the 1st outer side resin inflow prevention weir 42. FIG. It is needless to say that the step here does not have to be a right angle and may have a skirt or taper angle generated in the process.

The structure of the present embodiment is advantageous in the following points as compared with the structures of Reference Example 1 and Reference Example 2 . In the structures of Reference Example 1 and Reference Example 2 , since it is necessary to arrange an inner resin inflow prevention weir between the IDT portion and the bump, the layout of the piezoelectric substrate in the surface acoustic wave element is complicated. As a result, the deterioration of the characteristics due to the increase in the capacitance due to the proximity of the signal side wiring portion and the ground side wiring portion is likely to occur. Therefore, it was necessary to increase the size of the piezoelectric substrate in order to prevent this problem. . However, since the inner resin inflow prevention weir is not provided in this embodiment, it is not necessary to increase the size of the piezoelectric substrate. Further, since the outer resin inflow prevention weir (first outer resin inflow prevention weir in the present embodiment) and the IDT, reflector, and wiring part on the piezoelectric substrate come into contact with each other, it causes the sealing resin to flow. In consideration of manufacturing variations such as mounting accuracy of the surface acoustic wave element on the IDT, reflector, wiring portion, etc. on the piezoelectric substrate and the outer resin inflow prevention weir (first outer resin inflow prevention weir in the present embodiment) It is necessary to leave a certain distance between them. In the present embodiment, the second outer resin inflow prevention weir includes an IDT, a reflector, a wiring portion, and the like on the piezoelectric substrate and an outer resin inflow prevention weir (first outer resin inflow prevention weir in the present embodiment). Therefore, even if the second outer resin inflow prevention weir is added, it is not necessary to increase the size of the piezoelectric substrate.

  In the present embodiment, the following modifications may be employed. That is, as shown in FIG. 20, the first outer resin inflow prevention weir 42 provided on the functional surface of the surface acoustic wave element 2 may have a shape having no step. Even in this case, since the second outer resin inflow prevention weir 43 is provided at the inner peripheral position of the first outer resin inflow prevention weir 42, the sealing which seals the outer peripheral edge of the surface acoustic wave element 2 is performed. Even if the resin 5 flows in over the first outer resin inflow prevention weir 42, the sealing resin 5 that has passed over the first outer resin inflow prevention weir 42 by the second outer resin inflow prevention weir 43. It is possible to prevent low molecular components from flowing into the excitation unit 6.

  However, as described above, it goes without saying that the first outer resin inflow prevention weir 42 having a stepped shape can more reliably prevent the inflow of the sealing resin 5. Also in the present embodiment, similarly to the second embodiment, a substrate-side resin inflow prevention weir may be provided on the mounting substrate 3 at a position facing the first outer resin inflow prevention weir 42. Further, the total height of the first outer resin inflow prevention weir 42 and the substrate side resin inflow prevention weir is the height of the bump 4 after the surface acoustic wave element 2 and the mounting substrate 3 are connected via the bump 4. It is preferable that the height is set lower than the total height of the electrode lands 8 formed on the mounting surface of the mounting substrate 3.

(The invention's effect)
With the surface acoustic wave device configured according to the present invention, it is ensured that the sealing resin sealing the surface acoustic wave element and the mounting substrate flows into the excitation portion of the surface acoustic wave element. The effect that it can prevent is acquired.

It is a sectional side view which shows the structure of the surface acoustic wave apparatus concerning the reference example 1 . It is a top view which shows the structure of the mounting substrate concerning the reference example 1. FIG. 6 is a plan view showing a structure of a surface acoustic wave device according to Reference Example 1. FIG. 6 is a side sectional view showing a structure of a surface acoustic wave device according to a first modification of Reference Example 1. FIG. It is a sectional side view which shows the structure of the surface acoustic wave apparatus concerning the 2nd modification of the reference example 1 . It is a sectional side view which shows the structure of the surface acoustic wave apparatus concerning the 3rd modification of the reference example 1 . FIG. 10 is an explanatory diagram illustrating a manufacturing procedure of the surface acoustic wave device according to Reference Example 1 . It is explanatory drawing which shows the manufacture procedure of the surface acoustic wave apparatus concerning the reference example 1. FIG. 6 is a side sectional view showing a structure of a surface acoustic wave device according to Reference Example 2. FIG. 6 is a plan view showing a structure of a surface acoustic wave device according to Reference Example 2. FIG. Is a plan view showing a structure of the mounting board according to Example 2. FIG. 10 is an explanatory diagram illustrating a manufacturing procedure of the surface acoustic wave device according to Reference Example 2 . It is explanatory drawing which shows the manufacture procedure of the surface acoustic wave apparatus concerning the reference example 2. FIG. It is a sectional side view which shows the structure of the surface acoustic wave apparatus concerning the reference example 3 . 10 is a plan view showing a structure of a surface acoustic wave device according to Reference Example 3. FIG. 10 is a side sectional view showing a structure of a surface acoustic wave device according to a modification of Reference Example 3. FIG. It is a sectional side view which shows the structure of the surface acoustic wave apparatus concerning embodiment . It is a top view which shows the structure of the surface acoustic wave element concerning embodiment . It is a sectional side view which shows the structure of the surface acoustic wave apparatus concerning the 1st modification of embodiment . It is a sectional side view which shows the structure of the surface acoustic wave apparatus concerning the 2nd modification of embodiment . It is a sectional side view which shows the structure of the surface acoustic wave apparatus concerning the conventional form. It is a top view which shows the structure of the surface acoustic wave element concerning the conventional form. It is a top view which shows the structure of the mounting board | substrate concerning the conventional form.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Surface acoustic wave device 2 Surface acoustic wave element 3 Mounting board 4 Bump 5 Sealing resin 6 Excitation part 7 Vibration space 8 Electrode land 9 Outer resin inflow prevention weir 10 Inner resin inflow prevention weir h1 Height of outer resin inflow prevention weir h2 Bump height h3 Electrode land height h4 Total height h5 Inner resin inflow prevention weir height h6 Board side resin inflow prevention weir height h7 Total height

Claims (10)

A mounting surface of a mounting substrate and a surface acoustic wave device, comprising: a surface acoustic wave device having a functional surface including an excitation portion including at least one comb-shaped electrode portion formed on the piezoelectric substrate; a mounting substrate; and a sealing resin. The surface acoustic wave element and the mounting substrate are connected via bumps so that the functional surfaces of the surface acoustic wave element face each other, and the outer peripheral edge of the surface acoustic wave element is sealed with a sealing resin, A surface acoustic wave device in which a vibration space is secured between the excitation portion of the surface acoustic wave element and the mounting surface of the mounting substrate,
On the functional surface of the surface acoustic wave element, a first outer resin inflow prevention weir is disposed so as to surround the bump and the excitation portion, and the bump and the excitation portion are disposed inside the first outer resin inflow prevention weir. A surface acoustic wave device comprising the second outer resin inflow prevention weir. The surface acoustic wave device according to claim 1 , wherein the height of the first outer resin inflow prevention weir is higher than that of the second outer resin inflow prevention weir. The height of the first outer resin inflow prevention weir is the height of the bump after the surface acoustic wave element and the mounting substrate are connected via the bump and the height of the electrode land formed on the mounting surface of the mounting substrate. The height is set lower than the total height, and the height of the second outer resin inflow prevention weir is set lower than the height of the bump after the surface acoustic wave element and the mounting substrate are connected via the bump. The surface acoustic wave device according to claim 2 , wherein: The first outer resin inlet dam consists of at least two layers, the lowermost layer of the first outer resin inlet dam is characterized by having the same height as the second outer resin inlet dam, wherein The surface acoustic wave device according to any one of claims 1 to 3 . At least the second outer resin inflow prevention weir is formed by using a material whose sealing resin has poorer wettability than the functional surface of the surface acoustic wave element and the mounting surface of the mounting substrate. The surface acoustic wave device according to any one of claims 1 to 4 . 6. The surface acoustic wave device according to claim 5 , wherein the first outer resin inflow prevention weir has a step. The surface acoustic wave device according to claim 6 , wherein the step of the first outer resin inflow prevention weir is configured by at least one concave portion. The surface acoustic wave device according to claim 6 , wherein the step of the first outer resin inflow prevention weir is configured by at least one convex portion. The surface according to any one of claims 1 to 8 , further comprising a substrate-side resin inflow prevention weir formed on the mounting substrate so as to face the outer resin inflow prevention weir. Elastic wave device. The total height of the outer resin inflow prevention weir and the substrate side resin inflow prevention weir was formed on the mounting surface of the mounting substrate and the height of the bump after the surface acoustic wave element and the mounting substrate were connected via the bump. The surface acoustic wave device according to claim 9 , wherein the surface acoustic wave device is set to be lower than a total height of the electrode lands.

Images