JP5662052B2 - Elastic wave device - Google Patents

Description

  The present invention relates to an acoustic wave device such as a surface acoustic wave (SAW) device and a piezoelectric thin film resonator (FBAR), and a method for manufacturing the same.

  An acoustic wave device having a substrate, an acoustic wave element provided on the principal surface of the substrate, a cover for sealing the acoustic wave element, and a terminal provided on the principal surface of the substrate and penetrating the cover is known. (For example, Patent Document 1). In such an elastic wave device, a vibration space for facilitating the propagation of elastic waves is formed on the elastic wave element by a cover. In the technique of Patent Document 1, the vibration space is formed in a rectangular parallelepiped shape, and the terminal is formed in a cylindrical shape.

JP 2002-232260 A

  The inventor of the present application has discovered through experiments that cracks are generated in the cover starting from the periphery of the terminal when a severe temperature change is caused in the acoustic wave device. As a result of intensive studies, the inventor of the present application, as a cause of the crack, the cover is thin between the outer wall surface or inner wall surface of the cover and the side surface of the terminal around the terminal, and stress is concentrated. I found out that it was easy.

  On the other hand, the terminals are preferably formed with a certain thickness (cross-sectional area) in order to prevent the terminal from coming off, and the cover is required to be downsized. These requirements are in a trade-off relationship with the requirement for increasing the thickness of the cover around the terminals.

  An object of the present invention is to provide an elastic wave device capable of improving strength in the vicinity of a terminal of a cover.

  An elastic wave device according to a first aspect of the present invention includes a substrate, an elastic wave element provided on a main surface of the substrate, an inner wall surface constituting a part of a vibration space that houses the elastic wave element, and A cover having an outer wall surface that is an outer surface that does not face the vibration space; and a terminal that is disposed on the main surface and penetrates the cover in a vertical direction between the inner wall surface and the outer wall surface. In a plan view of the main surface, a geometrical relationship between a predetermined wall surface that is a part of the inner wall surface or the outer wall surface and a proximity surface located on the predetermined wall surface side of the side surface of the terminal is The geometrical relationship between the predetermined wall surface and the circumference of the largest virtual circle that fits in the cross-sectional shape of the terminal is closer to parallel.

  An acoustic wave device according to a second aspect of the present invention includes a substrate, an acoustic wave element provided on a main surface of the substrate, an inner wall surface constituting a part of a vibration space that houses the acoustic wave element, and A cover having an outer wall surface that is an outer surface that does not face the vibration space; and a terminal that is disposed on the main surface and penetrates the cover in a vertical direction between the inner wall surface and the outer wall surface. The terminal has a flange that protrudes from a side surface of the terminal and is stacked on the upper surface of the cover, and an upper end surface including the flange of the terminal in a plan view of the main surface has a triangular or pentagonal shape. It is formed in the shape including the above polygon or the contour of the curve, and is located on the predetermined wall surface side among the predetermined wall surface which is the inner wall surface or the outer wall surface and the outer peripheral edge portion of the upper end surface of the terminal. The geometric relationship with the adjacent edge Wherein the predetermined wall surface, than the geometric relationship between the circumference of the largest imaginary circle that will fit in the upper end surface of the terminal, nearly parallel.

  According to said structure, the strength improvement in the terminal vicinity of a cover can be aimed at.

1 is an external perspective view of a SAW device according to a first embodiment of the present invention. FIG. 2 is a schematic perspective view showing the SAW device of FIG. 1 in a partially broken state. FIG. 2 is a schematic plan view showing a wiring structure on a main surface of a substrate of the SAW device of FIG. 1. It is sectional drawing in the IV-IV line of FIG. 5A to 5D are cross-sectional views illustrating a method for manufacturing the SAW device of FIG. 6 (a) to 6 (c) are cross-sectional views showing a continuation of FIG. 5 (d). It is a typical top view explaining the effect of a 1st embodiment. It is a typical top view explaining the SAW device concerning a 2nd embodiment. It is sectional drawing parallel to the main surface of the board | substrate which shows the SAW apparatus which concerns on 3rd Embodiment. It is sectional drawing parallel to the main surface of the board | substrate which shows the SAW apparatus which concerns on 4th Embodiment. It is sectional drawing equivalent to FIG. 4 which shows the SAW apparatus which concerns on 5th Embodiment. 12A to 12C are cross-sectional views illustrating a method for manufacturing the SAW device of FIG. It is a partially expanded view of a cross-sectional view parallel to the main surface of a substrate showing a SAW device according to a sixth embodiment. It is a partially expanded view of a cross-sectional view parallel to the main surface of a substrate showing a SAW device according to a seventh embodiment. It is sectional drawing equivalent to FIG. 4 which shows the SAW apparatus which concerns on 8th Embodiment.

  Hereinafter, a SAW 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 embodiment to be described, the same or similar configuration as the already described embodiment may be denoted by the same reference numeral as the already described embodiment, and the description may be omitted.

  For the same or similar configuration, an uppercase alphabetic additional code may be added, such as “first terminal 7A to sixth terminal 7F”. In this case, the number at the beginning of the name, such as simply “terminal 7”, and the above additional code may be omitted.

<First Embodiment>
(Configuration of SAW device)
FIG. 1 is an external perspective view of a SAW device 1 according to the first embodiment of the present invention.

  The SAW device 1 is a so-called wafer level package (WLP) type SAW device. The SAW device 1 includes a substrate 3, a cover 5 fixed to the substrate 3, first terminals 7 </ b> A to 6 </ b> F exposed from the cover 5, and a back surface portion provided on the side opposite to the cover 5 of the substrate 3. 9.

  Signals are input to the SAW device 1 via any of the plurality of terminals 7. The input signal is filtered by the SAW device 1. Then, the SAW device 1 outputs the filtered signal via any of the plurality of terminals 7. The SAW device 1 is, for example, resin-sealed in a state where the surface on the cover 5 side faces a mounting surface such as a circuit board (not shown) and is placed on the mounting surface, whereby the terminal 7 is placed on the mounting surface. It is mounted while connected to the terminal.

  The substrate 3 is composed of a piezoelectric substrate. Specifically, for example, the substrate 3 is a rectangular parallelepiped single crystal substrate having piezoelectricity such as a lithium tantalate single crystal or a lithium niobate single crystal. The board | substrate 3 has the 1st main surface 3a and the 2nd main surface 3b of the back side. The planar shape of the substrate 3 may be set as appropriate. For example, the substrate 3 is a rectangle whose longitudinal direction is the Y direction. Although the magnitude | size of the board | substrate 3 may be set suitably, for example, thickness is 0.2 mm-0.5 mm, and the length of 1 side is 0.5 mm-2 mm.

  The cover 5 is provided so as to cover the first main surface 3a. The planar shape of the cover 5 is, for example, the same as the planar shape of the substrate 3, and in the present embodiment, it is a rectangle having the Y direction as the longitudinal direction. The cover 5 has, for example, a width approximately equal to that of the first main surface 3a and covers almost the entire surface of the first main surface 3a.

  The plurality of terminals 7 are exposed from the upper surface of the cover 5 (surface opposite to the substrate 3). The number and arrangement position of the plurality of terminals 7 are appropriately set according to the configuration of the electronic circuit inside the SAW device 1. In the present embodiment, six terminals 7 are arranged along the outer periphery of the cover 5.

  Although not particularly illustrated, the back surface portion 9 includes, for example, a back electrode that covers substantially the entire second main surface 3b and an insulating protective layer that covers the back electrode. The back surface electrode discharges the charge charged on the surface of the substrate 3 due to a temperature change or the like. Damage to the substrate 3 is suppressed by the protective layer. In addition, below, illustration and description of the back surface part 9 may be omitted.

  FIG. 2 is a perspective view of the SAW device 1 with a part of the cover 5 cut away.

  The cover 5 is formed in a frame shape, and includes a frame portion 35 disposed on the first main surface 3 a and a lid portion 37 that closes the opening of the frame portion 35. The first main surface 3a (strictly, a protective layer 25 described later), a space surrounded by the frame portion 35 and the lid portion 37, facilitates vibration of the SAW element 11 (see FIG. 3) described later. A vibration space 10A and a second vibration space 10B are formed.

  The cover 5 has an inner wall surface 5a that faces the inner side and forms the vibration space 10, and an outer wall surface 5b that faces the outer side. The inner wall surface 5a is constituted by a frame portion 35. The outer wall surface 5 b includes a frame part 35 and a lid part 37.

  The frame portion 35 is configured by forming an opening that becomes the vibration space 10 in a layer having a substantially constant thickness. The thickness of the frame part 35 (height of the vibration space 10) is, for example, several μm to 30 μm. The lid portion 37 is configured by a layer having a substantially constant thickness that is stacked on the frame portion 35. The thickness of the lid part 37 is, for example, several μm to 30 μm.

  The frame part 35 and the cover part 37 are made of, for example, photosensitive resin. The photosensitive resin is, for example, a urethane acrylate-based, polyester acrylate-based, or epoxy acrylate-based resin that is cured by radical polymerization of an acryl group or a methacryl group.

  The frame part 35 and the cover part 37 may be formed of the same material, or may be formed of different materials. In the present application, for convenience of explanation, the boundary line between the frame portion 35 and the lid portion 37 is clearly shown. However, in an actual product, the frame portion 35 and the lid portion 37 are formed of the same material and are integrally formed. May be.

  The terminal 7 is provided upright on the first main surface 3a and is exposed to the upper surface of the cover 5 through a hole 5h formed in the cover 5, as is apparent from the sixth terminal 7F in FIG. doing. Specifically, the terminal 7 passes through the frame portion 35 and the lid portion 37 between the inner wall surface 5a and the outer wall surface 5b in the direction in which the first main surface 3a faces.

  Moreover, the terminal 7 has the columnar part 7a formed in the column shape, and the flange 7b which protrudes from the side surface of the columnar part 7a. The columnar portion 7 a penetrates the cover 5, and the flange 7 b is laminated on the upper surface of the cover 5. The upper end surface of the terminal 7 including the flange 7b constitutes a land 7c connected to a circuit board or the like.

  The flange 7b is formed over the entire circumference of the columnar portion 7a and has a substantially constant width. Therefore, the shape of the land 7c is similar to that of the cross section parallel to the first main surface 3a of the columnar portion 7a.

  The first main surface 3a is provided with a first pad 13A to a sixth pad 13F (only a part is shown in FIG. 2) connected to the SAW element 11 (FIG. 3). The terminal 7 is connected to the SAW element 11 by being provided on the pad 13. The planar shape of the pad 13 may be any as long as the terminal 7 is within the range, but is slightly larger than the shape of the cross section parallel to the first main surface 3a of the columnar portion 7a. A similar shape is preferred.

  FIG. 3 is a schematic plan view showing a wiring structure on the first main surface 3 a of the substrate 3. In FIG. 3, the range of the vibration space 10 (the shape of the inner wall surface 5a), the cross-sectional shape of the columnar portion 7a, and the shape of the land 7c (flange 7b) are indicated by a two-dot chain line. In the description with reference to the plan view, the outline of the substrate 3 may be referred to as the outline of the outer wall surface 5b.

  A first SAW element 11A and a second SAW element 11B are provided on the first main surface 3a. The first SAW element 11A is, for example, a SAW resonator, and the second SAW element 11B is, for example, a SAW filter.

  The SAW element 11 includes one or more IDT (InterDigital Transducer) electrodes 15 and two reflectors 17 disposed on both sides of the SAW propagation direction (X direction) of the IDT electrode 15.

  The IDT electrode 15 is composed of a pair of electrodes. The pair of electrodes includes a bus bar 15a extending in the propagation direction (X direction) of the surface acoustic wave, and a plurality of electrode fingers 15b extending from the bus bar 15a in a direction (Y direction) perpendicular to the propagation direction. It arrange | positions so that 15b may mutually mesh. Since FIG. 3 is a schematic diagram, the number of electrode fingers 15b is smaller than the actual number.

  The plurality of pads 13 and the plurality of SAW elements 11 are appropriately connected via a plurality of wirings 27. Note that some of the plurality of wirings 27 cross each other through the insulator 21.

  The first vibration space 10A is formed on the first SAW element 11A, and the second vibration space 10B is formed on the second SAW element 11B. The two vibration spaces 10 are arranged in the longitudinal direction of the substrate 3.

  As shown in FIGS. 2 and 3, each vibration space 10 is generally formed in a hexagonal shape, and all six corners are obtuse. From another point of view, each vibration space 10 is formed in a rectangle whose longitudinal direction is the short direction of the substrate 3, and the corners can be regarded as chamfered. The first vibration space 10 </ b> A is partially expanded so as to accommodate the three-dimensional intersections of the plurality of wirings 27.

  For each vibration space 10, the plurality of terminals 7 are arranged adjacent to the four corners of the vibration space 10 when each vibration space 10 is regarded as a rectangle. The plurality of terminals 7 are opposed to a part of the inner wall surface (hereinafter also referred to as a chamfered surface 5c) corresponding to one of the two sides constituting the corner portion of the vibration space 10 that is an obtuse angle. .

  The columnar portion 7a of each terminal 7 is formed such that, of its side surfaces, the surfaces located on the inner wall surface 5a and the outer wall surface 5b side are parallel to the inner wall surface 5a and the outer wall surface 5b. Specifically, the columnar portion 7a of each terminal 7 has an inner proximity surface 7aa parallel to the inner wall surface 5a and an outer proximity surface 7ab parallel to the outer wall surface 5b.

  Since the first terminal 7A, the third terminal 7C, the fourth terminal 7D, and the sixth terminal 7F arranged at the corners of the cover 5 are adjacent to two orthogonal planes of the outer wall surface 5b, the two outer proximity It has a surface 7ab. Further, since these four terminals 7 are adjacent to one vibration space 10, they have one inner proximity surface 7aa. The columnar portions 7a of the four terminals 7 are generally formed in a right triangle having the inner proximity surface 7aa as a hypotenuse in plan view of the first main surface 3a. However, the acute corner is chamfered by a flat surface, and the columnar portion 7a can be regarded as a pentagon.

  The remaining second terminal 7B and fifth terminal 7E are adjacent to one plane of the outer wall surface 5b, and thus have one outer proximity surface 7ab. Further, since these two terminals 7 are sandwiched between the two vibration spaces 10, they have two inner proximity surfaces 7aa. The columnar portions 7a of the two terminals 7 are generally formed in an isosceles triangle having the outer proximity surface 7ab as a base in plan view of the first main surface 3a. However, the corner portion of the base angle is chamfered by a flat surface, and the columnar portion 7a can be regarded as a pentagon.

  As described above, the land 7c of each terminal 7 has a shape similar to the cross-sectional shape of the columnar portion 7a. Accordingly, similarly to the columnar portion 7a, the land 7c has an inner adjacent edge portion 7ca parallel to the inner wall surface 5a and an outer adjacent edge portion 7cb parallel to the outer wall surface 5b at the outer peripheral edge portion. Since the shape of the land 7c is similar to the shape of the columnar portion 7a, the description of the shapes of the terminals 7 at the four corners of the cover 5 and the other two terminals 7 is omitted.

  4 is a cross-sectional view taken along line IV-IV in FIG. However, FIG. 4 is drawn more conceptually than FIG. 3, and the SAW element 11 is shown more schematically than FIG.

  The SAW device 1 includes a first conductive layer 19 provided on the first main surface 3a, and a protective layer 25 stacked on the first conductive layer 19 and the first main surface 3a. The cover 5 is laminated on the protective layer 25. The terminal 7 includes a base layer 39 formed on the cover 5 and a solid portion 41 surrounded by the base layer 39.

  The first conductive layer 19 is a basic layer regarding the configuration of circuit elements, wirings, and the like on the first major surface 3a. Specifically, the first conductive layer 19 constitutes a part of the SAW element 11, the pad 13, and the plurality of wirings 27. The first conductive layer 19 is formed of, for example, an Al alloy such as an Al—Cu alloy, and the thickness thereof is, for example, 100 to 300 nm.

The protective layer 25 contributes to the oxidation prevention of the SAW element 11 and the like. The protective layer 25 is made of, for example, silicon oxide (such as SiO ₂ ), aluminum oxide, zinc oxide, titanium oxide, silicon nitride, or silicon. The thickness of the protective layer 25 is, for example, about 1/10 (10 to 30 nm) of the thickness of the first conductive layer 19. The protective layer 25 is formed over the entire first main surface 3a except for the position where the pad 13 is disposed.

  The underlayer 39 is formed of a metal such as copper or titanium, for example. The underlayer 39 is formed on the bottom surface of the hole 5 h, the inner peripheral surface of the hole 5 h, and the upper surface of the cover 5 around the hole 5 h. The thickness of the foundation layer 39 is substantially uniform. The thickness may be set as appropriate. For example, when the base layer 39 is made of copper, the thickness is 300 nm to 1 μm, and when the base layer 39 is made of titanium, the thickness is 10 nm to 100 nm.

  The solid part 41 is made of, for example, copper. The solid portion 41 is filled in the hole 5 h inside the base layer 39. Further, the solid portion 41 is formed higher than the upper surface of the cover 5 in the hole portion 5h, and is formed on the base layer 39 in the peripheral portion of the upper surface of the cover 5 around the hole portion 5h.

(Method for manufacturing SAW device)
FIG. 5A to FIG. 6C are cross-sectional views corresponding to FIG. 4 (IV-IV line in FIG. 3) for explaining the method for manufacturing the SAW device 1. The manufacturing process proceeds in order from FIG. 5 (a) to FIG. 6 (c).

  The steps described below are realized in a so-called wafer process. That is, a thin film formation, a photolithography method, or the like is performed on the mother substrate that becomes the substrate 3 by being divided, and then a large number of SAW devices 1 are formed in parallel by dicing. . However, in FIG. 5A to FIG. 6C, only a portion corresponding to one SAW device 1 is illustrated. In addition, although the shape of the conductive layer and the insulating layer changes with the progress of the process, a common code is used before and after the change.

  As shown in FIG. 5A, first, the first conductive layer 19 is formed on the first main surface 3 a of the substrate 3. Specifically, first, a metal layer to be the first conductive layer 19 is formed on the first main surface 3a by a thin film forming method such as a sputtering method, a vapor deposition method, or a CVD (Chemical Vapor Deposition) method. Next, the metal layer is patterned by a photolithography method using a reduction projection exposure machine (stepper) and an RIE (Reactive Ion Etching) apparatus. By patterning, the SAW element 11, the pad 13, and a part of the plurality of wirings 27 are formed. That is, the first conductive layer 19 is formed.

  When the first conductive layer 19 is formed, a protective layer 25 is formed as shown in FIG. Specifically, first, a thin film to be the protective layer 25 is formed by an appropriate thin film forming method. The thin film forming method is, for example, a sputtering method or a CVD method. Next, a part of the thin film is removed by photolithography so that the portion of the first conductive layer 19 that constitutes the pad 13 is exposed. Thereby, the protective layer 25 is formed.

  Although not particularly illustrated, when the protective layer 25 is formed, the insulator 21 (FIG. 3) and the second conductive layer 23 (FIG. 3) constituting the wiring 27 stacked on the insulator 21 are formed. Specifically, first, a thin film to be the insulator 21 is formed by a thin film forming method such as a CVD method or a vapor deposition method. Then, a part of the thin film is removed by photolithography, and the insulator 21 is formed. Next, similarly to the first conductive layer 19, the metal layer is formed and patterned, and another wiring 27 that three-dimensionally intersects the wiring 27 constituted by the first conductive layer 19 via the insulator 21 is formed. The That is, the second conductive layer 23 is formed.

  When the second conductive layer 23 is formed, a thin film that becomes the frame portion 35 is formed as shown in FIG. The thin film is formed, for example, by attaching a film formed of a photosensitive resin or by a thin film forming method similar to that for the protective layer 25.

  When the thin film to be the frame portion 35 is formed, as shown in FIG. 5D, a part of the thin film is removed by a photolithography method or the like, and the openings constituting the vibration space 10 and the holes 5h are formed. A hole 35h which is a lower portion is formed. The thin film is also removed with a constant width on the dicing line. In this way, the frame portion 35 is formed.

  When the frame portion 35 is formed, a lid portion 37 is formed as shown in FIG. Specifically, first, a thin film that becomes the lid portion 37 is formed. The thin film is formed, for example, by attaching a photosensitive resin film. When the thin film is formed, the opening of the frame portion 35 is closed, and the vibration space 10 is configured. In the thin film, a portion on the pad 13 and a portion on the dicing line are removed by a photolithography method or the like. Thereby, the cover part 37 is formed.

  The shape of the cross section parallel to the first main surface 3a of the hole 5h (including the hole 35h) formed at this time is the cross section parallel to the first main surface 3a of the columnar portion 7a of each terminal 7 described above. The shape is the same.

  When the lid portion 37 is formed, the base layer 39 and the resist layer 53 are sequentially formed as shown in FIG. The foundation layer 39 is formed over the upper surface of the cover 5 and the inside of the hole 5h. The underlayer 39 is formed by, for example, a sputtering method.

  The resist layer 53 is formed so that the base layer 39 is exposed at and around the hole 5h. The resist layer 53 is formed, for example, by forming a photosensitive resin thin film by spin coating or the like, and patterning the thin film by photolithography.

  The shape of the cross section of the resist layer 53 formed at this time parallel to the first main surface 3a of the hole 53h exposing the base layer 39 is the same as the shape of the land 7c of each terminal 7 described above. is there.

  When the resist layer 53 is formed, as shown in FIG. 6C, metal is deposited on the exposed portion of the base layer 39 by electroplating to form the solid portion 41.

  Thereafter, the portion of the base layer 39 covered with the resist layer 53 and the resist layer 53 are removed. Thereby, the terminal 7 which consists of the base layer 39 and the solid part 41 and has the cross-sectional shape described above is formed. The exposed surface of the terminal 7 from the cover 5 may be made of nickel, gold, or the like.

  FIG. 7 is a schematic plan view for explaining the effect of the present embodiment, taking the fourth terminal 7D as an example. Note that FIG. 7 is a mathematical diagram that can be used for the description of the columnar portion 7a and the description of the land 7c. Therefore, in addition to the reference numeral of the columnar portion 7a, the reference numeral of the land 7c is given in parentheses. ing. In FIG. 7, the terminal 7 has a triangular (pentagonal) corner chamfered by a curved surface.

  Consider the maximum virtual circle C1 that fits in the columnar portion 7a of the terminal 7. The terminal 7 of the present embodiment is based on such a terminal having a columnar part having the same cross-sectional shape as the virtual circle C1, and without shortening the shortest distance L from the inner wall surface 5a, The cross-sectional area can be increased. In other words, the wall thickness between the columnar portion 7a and the inner wall surface 5a can be ensured without increasing the size of the cover 5 while ensuring a sufficient cross-sectional area of the columnar portion 7a. And generation | occurrence | production of the crack resulting from stress concentration is suppressed by ensuring thickness.

  Such an effect is achieved because the geometric relationship between the inner proximity surface 7aa and the inner wall surface 5a is closer to the parallel than the geometric relationship between the circumference of the virtual circle C1 and the inner wall surface 5a (straight line). Can be seen.

  Here, closer to parallel means the distance on the normal line of the inner wall surface 5a between the inner wall surface 5a and the inner proximity surface 7aa (or the circumference of the virtual circle C1) with respect to the change in the position of the inner wall surface 5a. Let the change be smaller.

  For example, regarding the virtual circle C1, the distance y1 between the inner wall surface 5a and the virtual circle C1 at the position P1 on the inner wall surface 5a, and the position separated from the position P1 by the distance r (radius of the virtual circle C1) along the inner wall surface 5a. There is a difference in the distance r between the distance y2 between the inner wall surface 5a and the virtual circle C1 in P2.

  On the other hand, regarding the inner proximity surface 7aa of the terminal 7 of the present embodiment, the distance y1 between the inner wall surface 5a and the inner proximity surface 7aa at the position P1 and the distance y3 between the inner wall surface 5a and the inner proximity surface 7aa at the position P2 are: Are the same.

  That is, the change (0) of the distance between the inner wall surface 5a and the inner proximity surface 7aa with respect to the change from the position P1 to the position P2 on the inner wall surface 5a is the inner wall surface with respect to the change from the position P1 to the position P2 on the inner wall surface 5a. It is smaller than the change (r) in the distance between 5a and the circumference of the virtual circle C1.

  And since the change of such a distance is small, the protrusion amount to the inner wall surface 5a side of the terminal 7 is restrained relatively with respect to the cross-sectional area of the terminal. As a result, the downsizing of the cover as described above, The effects of securing the cross-sectional area of the terminal and improving the strength in the vicinity of the terminal of the cover are exhibited.

  In addition, as understood from the above description, in the present application, parallel words are not limited to words describing straight lines or planes. That is, in the present application, a curved line or a curved surface may be described using parallel words.

  Further, if the distance between the position P1 and the position P2 is extremely small, the relationship between the inner wall surface 5a and the virtual circle C1 is also almost parallel (the relationship between the inner wall surface 5a and the tangent line of the virtual circle C1 is the same). Therefore, in the determination of comparing the degree of parallelism, it is preferable that the distance between the position P1 and the position P2 is sufficiently large (for example, about the radius of the virtual circle).

  Although the relationship between the inner proximity surface 7aa and the inner wall surface 5a has been described, the same can be said for the relationship between the outer proximity surface 7ab and the outer wall surface 5b with reference to the virtual circle C1. Further, considering not only the thickness in plan view but also the three-dimensional thickness, the relationship between the inner adjacent edge portion 7ca and the inner wall surface 5a and the relationship between the outer adjacent edge portion 7cb and the outer wall surface 5b are also considered. The same can be said with reference to the maximum virtual circle that fits in the land 7c.

  Next, a virtual circle C2 having an area equivalent to the area of the cross section parallel to the first main surface 3a of the columnar portion 7a of the terminal 7 is considered. The terminal 7 according to the present embodiment can increase the shortest distance from the inner wall surface 5a without reducing the cross-sectional area when the terminal having the columnar portion having the same cross-sectional shape as the virtual circle C2 is considered as a reference. Is possible. In other words, the wall thickness between the columnar portion 7a and the inner wall surface 5a can be ensured without increasing the size of the cover 5 while ensuring a sufficient cross-sectional area of the columnar portion 7a. And generation | occurrence | production of the crack resulting from stress concentration is suppressed by ensuring thickness.

  Such an effect is achieved by the fact that the geometric relationship between the inner proximity surface 7aa and the inner wall surface 5a is more parallel than the geometric relationship between the circumference of the virtual circle C2 and the inner wall surface 5a (straight line). Can be seen.

  In addition, description of the effect | action by a parallel view and being close to parallel is the same as that on the basis of the virtual circle C1, and description is abbreviate | omitted. Further, the relationship between the inner proximity surface 7aa and the inner wall surface 5a has been described, but the same can be said for the relationship between the outer proximity surface 7ab and the outer wall surface 5b with reference to the virtual circle C2. The same applies to the relationship between the inner adjacent edge portion 7ca and the inner wall surface 5a and the relationship between the outer adjacent edge portion 7cb and the outer wall surface 5b with reference to a virtual circle having an area equivalent to the area of the land 7c. .

  In the above description, it has been described that the effect of the present embodiment is achieved by being relatively parallel in comparison with the virtual circle, but of course, if the geometric relationship is parallel itself, The effects of downsizing, securing the cross-sectional area of the terminal, and improving the strength in the vicinity of the terminal of the cover are preferably achieved. That is, preferably, the geometric relationship between the inner proximity surface 7aa and the inner wall surface 5a, the geometric relationship between the outer proximity surface 7ab and the outer wall surface 5b, and the geometric relationship between the inner proximity edge 7ca and the inner wall surface 5a. The relationship and the geometric relationship between the outer proximity edge portion 7cb and the outer wall surface 5b are relationships in which the distance from the inner wall surface 5a or the outer wall surface 5b does not change.

  In the plan view of the first main surface 3a, the inner proximity surface 7aa and the inner wall surface 5a of the terminal 7 are formed in straight lines parallel to each other. Therefore, the shape is simple and the design is easy. The same applies to the relationship between the outer proximity surface 7ab and the outer wall surface 5b, the relationship between the inner proximity edge portion 7ca and the inner wall surface 5a, and the relationship between the outer proximity edge portion 7cb and the outer wall surface 5b.

  In the plan view of the first main surface 3a, the vibration space 10 is chamfered at the corners by forming the chamfered surface 5c on the inner wall surface 5a, and the terminal 7 is close to the chamfered surface 5c, and the geometrical shape described above. Have an academic relationship. Therefore, the effect of increasing the thickness between the inner wall surface 5a and the terminal 7 while ensuring a large vibration space 10 is enhanced.

  Note that the effect of the above-described geometrical relationship being nearly parallel is that, from another viewpoint, in the plan view of the first main surface 3a, the inner proximity surface 7aa (outer proximity surface 7ab, inner proximity edge portion 7ca) of the terminal 7 is obtained. It can also be understood that the outer adjacent edge portion 7cb) is played by a smaller curvature than a virtual circle having an area equivalent to the area of the columnar portion 7a (land 7c).

  In the above embodiment, the SAW device 1 is an example of the acoustic wave device of the present invention, the SAW element 11 is an example of the acoustic wave device of the present invention, and the inner proximity surface 7aa, the outer proximity surface 7ab, and the inner proximity edge portion. 7ca and the outer proximity edge 7cb are examples of the proximity surface of the present invention.

<Second Embodiment>
FIG. 8 is a schematic plan view corresponding to FIG. 7 of the SAW device according to the second embodiment. Note that FIG. 8 can be used not only for the description of the columnar portion 107a but also for the description of the land 107c, as in FIG. 7, and therefore, the reference numeral of the land 107c is given in parentheses.

  Also in the terminal 107 of the second embodiment, as in the first embodiment, the geometric relationship between the inner proximity surface 107aa and the inner wall surface 5a, the geometric relationship between the outer proximity surface 107ab and the outer wall surface 5b, The geometric relationship between the inner adjacent edge portion 107ca and the inner wall surface 5a and the geometric relationship between the outer adjacent edge portion 107cb and the outer wall surface 5b are the geometrical relationship between the circumference of the virtual circle C1 or C2 and a straight line. Closer to parallel than relationship. And there exists an effect similar to 1st Embodiment.

  However, the inner proximity surface 107aa, the outer proximity surface 107ab, the inner proximity edge portion 107ca, and the outer proximity edge portion 107cb are not formed linearly in a plan view of the first main surface 3a, and are more than the virtual circle C1 or C2. It is formed in an arc shape with a small curvature.

  The terminal 107 of the second embodiment is close to a circle as compared to the first embodiment. In this case, in the terminal formation method exemplified in the first embodiment (a method in which a voltage is applied to the underlayer 39 covering the cover 5 to deposit metal, and the hole is filled with metal to form a terminal). There is an advantage that the metal is suitably filled in the hole.

<Third Embodiment>
FIG. 9 is a view showing a cross section parallel to the first main surface 3a at the position of the upper surface of the frame portion 235 of the SAW device according to the third embodiment.

  Also in the terminal 207 of the third embodiment, the inner proximity surface 207aa and the inner wall surface 205a are parallel to each other as in the first embodiment. That is, the distance between the inner proximity surface 207aa and the inner wall surface 205a is constant.

  However, in the third embodiment, the inner proximity surface 207aa is formed in a concave shape. Specifically, it is as follows.

  The vibration space 210 is formed in an oval shape (or an oval shape). The vibration space 210 can also be understood as having four corners of a rectangle chamfered by a curved chamfered surface 205c. The chamfered surface 205c is a curved surface having a convex outer side.

  The terminal 207 is disposed close to the chamfered surface 205c. The inner proximity surface 207aa is formed to be curved with the vibration space 10 side as a concave so that the distance from the chamfered surface 205c is constant.

  In the third embodiment, similarly to the first embodiment, it is possible to reduce the size of the cover, secure the cross-sectional area of the terminal, and improve the strength in the vicinity of the terminal of the cover. Further, as in the first embodiment, the effect is that the geometrical relationship between the inner proximity surface 207aa and the inner wall surface 205a is a circle and a straight line such as a maximum virtual circle (not shown) that fits in the columnar portion 207a. It can be understood that it is played by being close to parallel rather than the geometrical relationship.

  Although the inner wall surface 205a is curved, even in such a case, it can be determined whether or not it is relatively parallel, as in the first embodiment. That is, the inner wall surface 205a and the inner proximity surface 207aa are changed with respect to the change of the inner wall surface 205a from the position P1 to the position P2 (the distance between the position P1 and the position P2 along the inner wall surface 205a is, for example, the radius of a virtual circle). Depending on whether the changes in the distances y1 and y3 on the normals Ln1 and Ln2 of the wall surface 205a are smaller than the changes in the distances y1 and y2 with respect to the virtual circle shown in FIG. It can be determined whether or not.

  The geometric relationship between the inner proximity edge 207ca of the land 207c and the inner wall surface 205a is the same as the geometric relationship between the inner proximity surface 207aa and the inner wall surface 205a.

<Fourth Embodiment>
FIG. 10 is a view showing a cross section parallel to the first main surface 3a at the position of the upper surface of the frame portion 335 of the SAW device according to the fourth embodiment.

  Also in the terminal 307 of the fourth embodiment, the inner proximity surface 307aa and the inner wall surface 305a are parallel to each other as in the first embodiment. That is, the distance between the inner proximity surface 307aa and the inner wall surface 305a is constant.

  However, in the fourth embodiment, the columnar portion 307a has a circular cross-sectional shape. In other words, the columnar portion 307a swells toward the vibration space 310 side. The inner wall surface 307aa and the inner wall surface 305a are parallel to each other when the inner wall surface 305a swells to the opposite side of the terminal 307.

  In the fourth embodiment, similarly to the first embodiment, it is possible to reduce the size of the cover, secure the cross-sectional area of the terminal, and improve the strength in the vicinity of the terminal of the cover. In addition, as in the first embodiment, the effect is that the geometric relationship between the inner proximity surface 307aa and the inner wall surface 305a is a circle and a straight line such as a maximum virtual circle (not shown) that can be accommodated in the columnar portion 307a. It can be understood that it is played by being close to parallel rather than the geometrical relationship.

  The geometric relationship between the inner proximity edge 307ca of the land 307c and the inner wall surface 305a is the same as the geometric relationship between the inner proximity surface 307aa and the inner wall surface 305a.

<Fifth Embodiment>
FIG. 11 is a cross-sectional view corresponding to FIG. 4 of the SAW device 401 according to the fifth embodiment.

  The SAW device 401 is different from the SAW device 1 of the first embodiment only in that the terminal 407 has a flange 407d inside the cover. In the terminal 407, the shapes of the columnar portion 7a and the flange 7b are the same as those in the first embodiment.

  The flange 407 d is disposed between the frame portion 35 and the lid portion 37. The planar shape of the flange 407d is the same as that of the flange 7b. That is, although not particularly illustrated, in the flange 407d, the geometric relationship between the inner adjacent edge and the inner wall surface 5a and the geometric relationship between the outer adjacent edge and the outer wall surface 5b are the maximum that can be accommodated in the flange 407d. It is closer to the parallel than the geometrical relationship between a circumference such as a virtual circle and a straight line.

  12A to 12C are cross-sectional views illustrating a method for manufacturing the SAW device 401 according to the fifth embodiment.

  Until the formation of the frame portion 35, the fifth embodiment is the same as the first embodiment. That is, also in the fifth embodiment, the steps from FIG. 5A to FIG. 5D of the first embodiment are performed.

  Next, as shown in FIG. 12A, a first base layer 39A and a first resist layer 53A are formed in order. The first base layer 39A is formed over the upper surface of the frame portion 35 and the inside of the hole portion 35h. The first resist layer 53A is formed so that the first base layer 39A is exposed at and around the hole 35h.

  When the first resist layer 53A is formed, as shown in FIG. 12B, metal is deposited on the exposed portion of the first base layer 39A by electroplating, and the first solid portion in the lower portion of the terminal 407 is formed. A portion 41A is formed. Then, portions of the first resist layer 53A and the first base layer 39A that are covered with the first resist layer 53A are removed.

  Thereafter, as shown in FIG. 12C, the same steps as those in FIG. 6A and subsequent steps of the first embodiment are performed. That is, the lid 37 is formed, the second base layer 39B and the second resist layer 53B are formed, the metal is deposited by plating, and the second resist layer 53B is removed. However, in the metal deposition, the second solid portion 41B on the upper side of the terminal 407 is formed.

  In the present embodiment, the case where the flange 407d is formed by the first base layer 39A and the first solid portion 41A is shown, but after the step of FIG. 12A, the first resist layer 53A and The portion where the first resist layer 53A is laminated is removed from the first base layer 39A, and then the steps after FIG. 6A are performed to form the flange 407d only by the first base layer 39A. it can.

  The flange 407d can contribute to suppressing the terminal 7 from being pulled out from the cover 5. As a result, it is possible to reduce the cross-sectional area of the columnar portion 7a, and as a result, it is possible to enhance the effect exhibited by the geometrical relationship close to parallel.

<Sixth Embodiment>
FIG. 13 is a partially enlarged view of a cross-sectional view parallel to the first main surface 3a at the position of the upper surface of the frame portion of the SAW device according to the sixth embodiment.

  In the terminal 507 of the sixth embodiment, the shape of the columnar portion 7a is the same as the shape of the columnar portion 7a of the terminal 7 of the first embodiment. However, in the terminal 507 of the sixth embodiment, the shape of the land 307c is the same as the shape of the land 307c of the fourth embodiment. That is, in the terminal 507 of the sixth embodiment, only the columnar portion 7a has portions parallel to the inner wall surface 5a and the outer wall surface 5b.

  In the sixth embodiment, a circular shape is illustrated as the shape of the land, but the shape of the land may be an appropriate shape such as a rectangle. As described above, by obtaining the effect of the parallel geometric relationship only in the columnar portion, the shape of the land is designed in consideration of the shape of the land on the circuit board side on which the SAW device is mounted. can do.

<Seventh Embodiment>
FIG. 14 is a partially enlarged view of a cross-sectional view parallel to the first main surface 3a at the position of the upper surface of the frame portion of the SAW device according to the seventh embodiment.

  In the terminal 607 of the seventh embodiment, contrary to the sixth embodiment, only the land 7c has portions parallel to the inner wall surface 5a and the outer wall surface 5b. The cross-sectional shape of the columnar portion 307a of the terminal 607 is a circle similar to the cross-sectional shape of the columnar portion 307a of the fourth embodiment.

  In such a terminal 607, the effect of improving the strength of the cover 5 due to the parallel geometrical relationship is obtained in the land 7c, and the effect of facilitating metal filling in the columnar portion 307a is obtained.

<Eighth Embodiment>
FIG. 15 is a cross-sectional view corresponding to FIG. 4 of the SAW device 501 according to the eighth embodiment.
The SAW device 501 is different from the SAW device 1 of the first embodiment in the cross-sectional shape when the terminal 507 is cut in the vertical direction (vertical direction of the paper surface).

  That is, in the SAW device 501, the terminal 507 has a tapered portion having a diameter larger on the first main surface 3a side than on the opposite side to the first main surface 3a. Since the terminal 507 has such a shape, the terminal 507 can be prevented from being pulled out from the cover 5. The shape of the cross section of the terminal 507 parallel to the first major surface 3a is the same as that of the SAW device 1 of the first embodiment.

  The present invention is not limited to the above embodiments and modifications, and may be implemented in various aspects.

  The elastic wave device is not limited to the SAW device. For example, the acoustic wave device may be a piezoelectric thin film resonator.

  In the acoustic wave device, the protective layer (25) may be omitted, or conversely, other appropriate layers may be formed. For example, a connection reinforcing layer interposed between the pad 13 and the terminal 7 and a circuit configuration layer formed between the frame portion and the lid portion may be provided.

  Moreover, you may provide the metal layer for reinforcing a cover part on a cover part. By providing the metal layer on the lid, even when a large pressure is applied from the outside, the lid can be prevented from being deformed and the vibration space can be prevented from being greatly distorted. Such a metal layer is made of Cu, for example, and can be produced by plating in the same process as forming the terminal.

  The area and shape of the cross section of the terminal parallel to the main surface may not be constant from the main surface side to the upper surface side of the cover. For example, the terminal may be formed in a taper shape in which the diameter of the main surface side is increased or the diameter of the main surface side is reduced.

  DESCRIPTION OF SYMBOLS 1 ... Surface acoustic wave apparatus (elastic wave apparatus), 3 ... Board | substrate, 3a ... 1st main surface (main surface), 5 ... Cover, 5a ... Inner wall surface, 5b ... Outer wall surface, 5c ... Chamfering surface (predetermined wall surface), 7 ... Terminal, 7aa ... Inner proximity surface, 7ab ... Outer proximity surface, 10 ... Vibration space, 11 ... SAW element (elastic wave element), C1 ... Virtual circle.

Claims (6)

A substrate,
An acoustic wave element provided on a main surface of the substrate;
A cover having an inner wall surface that constitutes a part of a vibration space that houses the acoustic wave element, and an outer wall surface that is an outer surface that does not face the vibration space;
A terminal disposed on the main surface and penetrating the cover in a vertical direction between the inner wall surface and the outer wall surface;
With
In a plan view of the main surface, a geometrical relationship between a predetermined wall surface that is a part of the inner wall surface and a proximity surface located on the predetermined wall surface side of the side surface of the terminal is parallel to the main surface and the Nearer parallel than the geometrical relationship between the straight line located outside the terminal and the circumference of the largest virtual circle that fits in the cross-sectional shape of the terminal,
In the plan view of the main surface, the proximity surface of the terminal swells to the predetermined wall surface side, and the predetermined wall surface swells to the side opposite to the terminal. In a plan view of the main surface, the geometric relationship between the predetermined wall surface and the proximity surface of the terminal is a geometry of the straight line and the circumference of a virtual circle having an area equivalent to the area of the terminal. The elastic wave device according to claim 1, wherein the elastic wave device is closer to parallel than the target relationship. The elastic wave device according to claim 1, wherein the proximity surface of the terminal and the predetermined wall surface are parallel in a plan view of the main surface. The terminal has a flange protruding from the side surface and laminated on the upper surface of the cover,
In the plan view of the main surface, the geometric relationship between the predetermined wall surface and the adjacent edge portion located on the predetermined wall surface side of the outer peripheral edge portion of the upper end surface including the flange of the terminal is the straight line, The elastic wave device according to any one of claims 1 to 3, wherein the elastic wave device is closer to parallel than a geometrical relationship with a circumference of a maximum virtual circle that fits on the upper end surface of the terminal. A substrate,
An acoustic wave element provided on a main surface of the substrate;
A cover having an inner wall surface that constitutes a part of a vibration space that houses the acoustic wave element, and an outer wall surface that is an outer surface that does not face the vibration space;
A terminal disposed on the main surface and penetrating the cover in a vertical direction between the inner wall surface and the outer wall surface;
With
The terminal has a flange that protrudes from a side surface of the terminal and is laminated on an upper surface of the cover,
In a plan view of the main surface, an upper end surface including the flange of the terminal is formed in a shape including a curved outline, and a predetermined wall surface that is a part of the inner wall surface, and the upper end surface of the terminal The geometrical relationship between the outer peripheral edge portion and the adjacent edge portion located on the predetermined wall surface side is the largest virtual line that fits in the straight line parallel to the main surface and located outside the flange and the upper end surface of the terminal. It is closer to parallel than the geometric relationship with the circumference of the circle,
In the plan view of the main surface, the adjacent edge portion of the terminal swells toward the predetermined wall surface, and the predetermined wall surface swells on the side opposite to the terminal. In a plan view of the major surface, the cross-sectional shape of the pin is circular
The elastic wave apparatus of any one of Claims 1-5 .

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