JP5756715B2 - Piezoelectric device manufacturing method and piezoelectric device - Google Patents

Description

  The present invention relates to a piezoelectric device including a piezoelectric element. The piezoelectric element is an element using a piezoelectric body, and is, for example, a surface acoustic wave (SAW) element, a piezoelectric thin film resonator, or a boundary acoustic wave element (included in a broad sense SAW element).

  Japanese Patent Application Laid-Open No. 2004-133620 discloses a device having a support member (package substrate) and an element (semiconductor chip) mounted on the support member, which is related to a semiconductor device. The element is mounted face-up on the support member.

  This device manufacturing method includes a step of mounting a plurality of elements on a mother board of a support member, and a step of cutting the mother board into individual pieces on the support member, and thus obtaining individual pieces comprising the element and the support member. Contains. Thus, productivity can be improved by mounting the element on the mother board of the support member and then separating the element.

JP 2008-171962 A

  It is conceivable to apply the mounting / separation technique of Patent Document 1 to a piezoelectric device. That is, it is conceivable to mount a plurality of piezoelectric elements on a mother board of a support member, and then cut the mother board to divide the support member into individual pieces to produce a piezoelectric device including the piezoelectric elements and the support member. However, the piezoelectric device manufacturing method obtained by simply replacing the technique of Patent Document 1 as described above is not necessarily suitable for a piezoelectric device.

  An object of the present invention is to provide a method of manufacturing a piezoelectric device that can be suitably mounted and separated.

  The method for manufacturing a piezoelectric device according to one aspect of the present invention includes a step of preparing a mother substrate including a plurality of support members and a mother substrate including a plurality of piezoelectric elements, and the plurality of piezoelectric elements are the plurality of support members. The two mother boards are opposed to each other so as to be face-down mounted on each other, and the two mother boards are connected to each other by bumps interposed between the opposing faces, and the two mother boards connected are cut. And forming a plurality of first pieces including the support member and the piezoelectric element.

Preferably, the manufacturing method includes a step of forming a bonding substrate in which a groove between the plurality of first pieces is filled with a resin material and bonding the plurality of first pieces to each other, and the bonding substrate Forming a plurality of conductive layers respectively connected to the plurality of first pieces, and cutting the resin material of the groove to the surface of the support member, the piezoelectric element, the cut Forming an expansion member made of a resin material and bonded to a side surface of the support member, and a plurality of second pieces including the conductive layer.

  Preferably, the conductive layer includes an external terminal provided on the expansion member and connected to the piezoelectric element.

  Preferably, in the step of forming the plurality of first pieces, the two mother substrates are cut with the same blade.

  According to the above procedure, mounting and singulation can be suitably performed.

FIG. 1A and FIG. 1B are perspective views of the appearance of the piezoelectric device according to the first embodiment of the present invention as seen from the upper surface side and the lower surface side. 2A is a schematic cross-sectional view taken along line IIa-IIa in FIG. 1A, FIG. 2B is a schematic cross-sectional view taken along line IIb-IIb in FIG. FIG. 2C is an enlarged view of a region IIc in FIG. FIGS. 3A to 3E are cross-sectional views illustrating a method for manufacturing the piezoelectric device of FIG. 4A to 4E are cross-sectional views showing a continuation of FIG. Sectional drawing which shows the piezoelectric device of the 2nd Embodiment of this invention. Sectional drawing which shows the piezoelectric device of the 3rd Embodiment of this invention. Sectional drawing which shows the piezoelectric device of the 4th Embodiment of this invention. Sectional drawing which shows the piezoelectric device of the 5th Embodiment of this invention. FIG. 9A is a cross-sectional view showing the piezoelectric device of the sixth embodiment, and FIG. 9B is an enlarged view of a region IXb in FIG. 9A. FIG. 10A is a sectional view showing the piezoelectric device of the seventh embodiment, and FIG. 10B is a sectional view taken along line Xb-Xb in FIG.

  Hereinafter, a piezoelectric 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.

(First embodiment)
FIG. 1A is a perspective view seen from the upper surface side showing the appearance of the piezoelectric device 1 according to the first embodiment of the present invention, and FIG. 1B is the lower surface side showing the appearance of the piezoelectric device 1. It is the perspective view seen from.

  The piezoelectric device 1 may have either direction upward or downward, but for convenience, the orthogonal coordinate system xyz is defined and the positive side in the z direction is upward, and the upper or lower surface of the piezoelectric device 1 is defined. Words shall be used.

  The piezoelectric device 1 is formed, for example, in a substantially rectangular parallelepiped shape, and has an upper surface 1a, a lower surface 1b, and four side surfaces 1c. On the lower surface 1b, a plurality of external terminals 3 are exposed in an appropriate shape and an appropriate number. Although the magnitude | size of the piezoelectric device 1 may be made into an appropriate magnitude | size, the length of 1 side is 1 mm-several mm, for example.

  The piezoelectric device 1 is arranged with a lower surface 1b facing a mounting substrate (not shown), and a pad provided on the mounting substrate and a plurality of external terminals 3 are joined via solder bumps or the like. To be implemented. The piezoelectric device 1 receives a signal, for example, via the external terminal 3, performs a predetermined process on the input signal, and outputs the signal.

  2A is a schematic cross-sectional view taken along line IIa-IIa in FIG. 1A, and FIG. 2B is a schematic cross-sectional view taken along line IIb-IIb in FIG. FIG. 2C is an enlarged view of a region IIc in FIG.

  The piezoelectric device 1 includes a base substrate 5, a piezoelectric element 7 face-down mounted on the base substrate 5, and an expansion member 9 that covers them.

  The base substrate 5 is constituted by, for example, a rigid printed wiring board, and includes an insulating base 11, an upper surface conductive layer 13A formed on the upper surface 11a of the insulating base 11, and the inside of the insulating base 11 parallel to the upper surface 11a. And the via conductor 15 penetrating all or part of the insulating substrate 11 in the vertical direction. The base substrate 5 may not be provided with the internal conductive layer 13B.

  The insulating base 11 is formed, for example, in a substantially rectangular parallelepiped shape, and has an upper surface 11a, a lower surface 11b, and four side surfaces 11c. The insulating base 11 is formed including, for example, a resin, a ceramic, and / or an amorphous inorganic material. The insulating substrate 11 may be made of a single material, or may be made of a composite material such as a substrate in which a base material is impregnated with a resin.

  The upper conductive layer 13 </ b> A includes a substrate pad 17 for mounting the piezoelectric element 7 on the base substrate 5. The via conductor 15 and the internal conductive layer 13 </ b> B include wiring that connects the substrate pad 17 and the external terminal 3. The top conductive layer 13A, the internal conductive layer 13B, and the via conductor 15 may include an inductor, a capacitor, or a circuit that performs appropriate processing. The top conductive layer 13A, the internal conductive layer 13B, and the via conductor 15 are made of, for example, a metal such as Cu.

  The piezoelectric element 7 is, for example, a SAW element, and is provided on the piezoelectric substrate 19, the excitation electrode 21 (FIG. 2C) provided on the functional surface 19 a of the piezoelectric substrate 19, the functional surface 19 a, and the base substrate 5. And an element pad 25 connected to the. In addition, the piezoelectric element 7 may include appropriate members such as a protective layer that covers the excitation electrode 21 and an electrode that covers the back surface 19b.

  The piezoelectric substrate 19 is formed, for example, in a substantially rectangular parallelepiped shape, and has a functional surface 19a, a back surface 19b serving as a back surface thereof, and four side surfaces 19c. The shape and size of the piezoelectric substrate 19 in plan view are the same as the shape and size of the base substrate 5 in plan view, for example. The side surface 19c of the piezoelectric substrate 19 and the side surface 11c of the base substrate 5 are flush with each other. The piezoelectric substrate 19 is configured by a single crystal substrate having piezoelectricity, such as a lithium tantalate single crystal or a lithium niobate single crystal.

  The excitation electrode 21 is a so-called IDT (InterDigital transducer), and includes a pair of comb electrodes 23 (see FIG. 10B). Each comb-tooth electrode 23 has a bus bar 23a (see FIG. 10B) and a plurality of electrode fingers 23b (see FIG. 2C, see FIG. 10B) extending from the bus bar 23a. The pair of comb electrodes 23 are arranged so as to mesh with each other (a plurality of electrode fingers 23b cross each other). 2 and 10 are schematic diagrams, and therefore only one pair of comb-tooth electrodes 23 having a plurality of electrode fingers 23b is shown, but in reality, more electrode fingers 23b than this are shown. There may be provided a plurality of pairs of comb-tooth electrodes 23. The excitation electrode 21 constitutes a SAW filter, a SAW resonator, and / or a duplexer.

  When a signal is input to the excitation electrode 21, the signal is converted into SAW and propagates in the direction (y direction) orthogonal to the electrode finger 23 b through the functional surface 19 a, converted into a signal again, and output from the excitation electrode 21. The In the process, the signal is filtered.

  The element pad 25 is connected to the excitation electrode 21 via a wiring (not shown) formed on the functional surface 19a. The excitation electrode 21 receives a signal via the element pad 25 and outputs a signal via the element pad 25.

  The excitation electrode 21, the element pad 25, and the wiring (not shown) connecting them are made of an appropriate metal such as an Al—Cu alloy, for example. These may be formed of the same material, or may be formed of different materials.

  The element pad 25 and the substrate pad 17 are joined by a bump 27. The bump 27 is made of solder. The solder may be a solder using lead such as Pb—Sn alloy solder, or lead-free solder such as Au—Sn alloy solder, Au—Ge alloy solder, Sn—Ag alloy solder, Sn—Cu alloy solder, etc. It may be. Note that the bumps 27 may be formed of a conductive adhesive.

  Since the bump 27 is interposed between the element pad 25 and the substrate pad 17, a gap (vibration space S) is formed between the upper surface 11 a of the insulating base 11 and the functional surface 19 a of the piezoelectric substrate 19. ing. Thereby, the vibration (SAW propagation) of the functional surface 19a is facilitated.

  For example, the expansion member 9 covers the other portions of the base substrate 5 and the piezoelectric element 7 while exposing the lower surface 11 b of the base substrate 5. That is, the expansion member 9 is joined to the side surface 11 c of the base substrate 5, joined to the side surface of the piezoelectric element 7, and joined to the back surface 19 b of the piezoelectric element 7.

  The upper surface 1 a and the side surface 1 c of the piezoelectric device 1 are constituted by the upper surface and the side surface of the expansion member 9, the outer peripheral side of the lower surface 1 b is constituted by the lower surface 9 b of the expansion member 9, and the inner side of the lower surface 1 b is the lower surface of the base substrate 5. 11b.

  The expansion member 9 is made of an insulating material. The insulating material is, for example, a resin such as an epoxy resin. In the resin, a filler made of insulating particles formed of a material having a lower thermal expansion coefficient than the resin may be mixed. Examples of the material of the insulating particles include silica, alumina, phenol, polyethylene, glass fiber, and graphite filler. In addition, the whole expansion member 9 may be comprised with inorganic insulating materials, such as a ceramic.

  The expansion member 9 preferably has a Young's modulus lower than that of the insulating base 11 (base substrate 5) from the viewpoint of shock absorption and the like. The expansion member 9 preferably has a thermal expansion coefficient equivalent to that of the insulating substrate 11 (base substrate 5) from the viewpoint of connection reliability with the insulating substrate 11 (base substrate 5). Here, the Young's modulus or thermal expansion coefficient is the Young's modulus or thermal expansion coefficient of the entire member when the expansion member 9 or the like is made of a composite material (Young's modulus or thermal expansion coefficient of some materials). is not.).

  A sheet 29 is interposed between the expansion member 9 and the base substrate 5 and the piezoelectric element 7. In addition, although the sheet | seat 29 can also be grasped | ascertained as a part of the expansion member 9, in this embodiment, the sheet | seat 29 and the expansion member 9 are demonstrated as a different member. As will be described later, the sheet 29 is for preventing the resin constituting the expansion member 9 from flowing into the vibration space S when the expansion member 9 is formed. The sheet 29 is made of, for example, a resin such as poniphenylene sulfide (PPS), and the thickness thereof is, for example, 1 to several μm.

  The plurality of external terminals 3 are provided on the lower surface 11 b of the base substrate 5 and / or the lower surface 9 b of the expansion member 9. In the present embodiment, the plurality of external terminals 3 include an external terminal 3 provided only on the lower surface 11 b of the base substrate 5, and an external terminal 3 provided from the lower surface 11 b of the base substrate 5 to the lower surface 9 b of the expansion member 9. Is included. All the external terminals 3 are at least partially provided on the lower surface 11 b of the base substrate 5 and are connected to the via conductors 15.

  FIG. 3A to FIG. 4E are cross-sectional views illustrating a method for manufacturing the piezoelectric device 1. Note that the cross-sectional view corresponds to the line IIb-IIb in FIG. 1A and is more schematically shown than in FIG.

  First, as shown in FIG. 3A, a mother board 31 on which a large number of base boards 5 are taken is prepared. The mother board 31 may be formed by various known methods. For example, if the base substrate 5 is a ceramic multilayer substrate, the mother substrate 31 is arranged with a plurality of ceramic green sheets serving as the insulating base 11 and a conductive paste serving as the top conductive layer 13A, the internal conductive layer 13B, and the via conductor 15; The plurality of ceramic green sheets may be laminated and fired. For example, if the base substrate 5 is a multilayer substrate using a resin as an insulating material, the mother substrate 31 is formed by laminating an inner core, a prepreg, and a copper foil to form the insulating substrate 11 and the inner conductive layer 13B, and through-hole plating. A through-hole conductor corresponding to the via conductor 15 may be formed by the above, and the upper surface conductive layer 13A may be formed by a subtractive or additive method. In addition, although the magnitude | size of the mother board | substrate 31 may be made into an appropriate magnitude | size, a diameter is about 4 inches as an example.

  Next, similarly as shown in FIG. 3A, bumps 27 for joining the base substrate 5 and the piezoelectric elements 7 are formed on the upper surface 11 a of the mother substrate 31. The bumps 27 are formed by, for example, a vapor deposition method, a plating method, or a printing method.

  In parallel with the preparation of the mother board 31, a mother board 33 (FIG. 3B) from which a large number of piezoelectric elements 7 are taken is also prepared. For example, the mother substrate 33 is formed by forming a metal layer on a mother substrate made of a piezoelectric body from which a large number of piezoelectric substrates 19 are formed by a thin film forming method such as a sputtering method, a vapor deposition method, or a CVD (Chemical Vapor Deposition) method. The metal layer is formed by patterning by a photolithography method or the like to form the excitation electrode 21, the element pad 25, and the like.

  Next, as shown in FIG. 3B, the functional surface 19 a of the mother substrate 33 of the piezoelectric element 7 is disposed so as to face the upper surface 11 a of the mother substrate 31 of the base substrate 5. Then, the bumps 27 are melted by passing these mother substrates through a reflow furnace, and the mother substrate 31 and the mother substrate 33 are joined.

  Next, as shown in FIG. 3C, the dicing tape 35 is bonded to the lower surface 11 b of the mother board 31. The dicing tape 35 is, for example, one in which an adhesive layer is formed on one side of a flexible resin film.

  Next, as shown in FIG. 3D, the mother board 31 and the mother board 33 are cut. Thereby, the first piece 8 including the base substrate 5 and the piezoelectric element 7 is formed. The cutting is performed by, for example, full cut dicing using a dicing blade. The cutting may be performed using a laser.

  The mother board 31 and the mother board 33 are cut together (at the same time and once) by the same blade (or laser setting). That is, the blade (or laser beam) moves relative to the mother substrate 31 and the mother substrate 33 in a state of penetrating both the mother substrate 31 and the mother substrate 33, and the mother substrate 31 and the mother substrate 33 are moved. Cut. Thereby, the side surface 11c of the base substrate 5 and the side surface 19c of the piezoelectric element 7 are flush with each other.

  However, after cutting only the mother substrate 33 by moving the blade relative to the mother substrate 31 and the mother substrate 33 in a state where the blade penetrates only the mother substrate 33, the mother substrate 31 is cut by another blade or laser light. For example, the mother board 31 and the mother board 33 may be cut sequentially and in different ways.

  Next, as shown in FIG. 3E, a plurality of sheets 37 from which a large number of sheets 29 are taken are placed on the plurality of first pieces 8. The sheet 37 is a flexible resin sheet having adhesiveness, for example. By evacuating the sheet 37 and the dicing tape 35, the sheet 37 adheres to and adheres to the exposed portion of the dicing tape 35, the side surface 11c of the base substrate 5, the side surface 19c and the back surface 19b of the piezoelectric element 7. .

  Next, as shown in FIG. 4A, a molten resin 39 to be the expansion member 9 is supplied so as to cover the plurality of first pieces 8. The molten resin 39 is supplied by, for example, a printing method. The supplied molten resin 39 fills the grooves 36 between the plurality of first pieces 8 and covers the back surface 19 b side of the piezoelectric element 7. The lower surface 11 b of the base substrate 5 is not covered with the resin 39 because it is in close contact with the dicing tape 35. The dicing tape 35 functions as a tray that prevents the resin 39 from flowing down from the groove 36.

  Thereafter, when the resin 39 is cured, the plurality of first pieces 8 are fixed to each other by the resin 39. That is, the plurality of first pieces 8 are integrated again to form a bonded substrate 40 such as a mother substrate.

  The dicing tape 35 is preferably expanded in an appropriate amount from before the sheet 37 is covered until the resin 39 is cured. Due to the expansion, the grooves 36 between the plurality of first pieces 8 are enlarged and appropriately sized.

  Next, as shown in FIG. 4B, the dicing tape 35 is peeled off from the bonding substrate 40. Thereby, the lower surface 11b of the base substrate 5 is exposed. Further, the direction of the bonding substrate 40 can be changed so that the lower surface 11b of the base substrate 5 faces upward.

  Next, as shown in FIG. 4C, the exposed portion of the sheet 37 from the resin 39 is removed. This process may be performed by a chemical process such as etching, or may be performed by a physical process such as polishing. The etching may be dry etching or wet etching.

  Next, as illustrated in FIG. 4D, the external terminals 3 are formed on the bonding substrate 40. Specifically, a metal layer is formed on the lower surface 11b of the base substrate 5 and the surface on the lower surface 11b side of the resin 39 by a thin film forming method such as a sputtering method, a vapor deposition method or a CVD method, and the metal layer is formed by a photolithography method or the like. It is formed by patterning.

  Next, as shown in FIG. 4E, a dicing tape 41 is bonded to the surface of the resin 39 opposite to the lower surface 11b, and the bonding substrate 40 is cut. More specifically, the resin 39 filled in the groove 36 is cut by a dicing blade thinner than the groove 36. As a result, a plurality of sets of base substrate 5 and piezoelectric element 7 are separated again, and the piezoelectric device 1 including the expansion member 9 is manufactured. Note that the cutting may be performed by a laser.

  As described above, in the present embodiment, the piezoelectric device 1 includes the base substrate 5, the piezoelectric element 7 mounted on the base substrate 5, the expansion member 9 joined to the side surface 11 c of the base substrate 5, and the expansion member. 9 and an external terminal 3 provided on the lower surface 9b.

  Accordingly, the range in which the external terminals 3 can be arranged is increased, and the degree of freedom in design is improved. In addition, the dimensions of the expansion member 9 and the arrangement of the external terminals 3 can be changed without changing the dimensions of the base substrate 5 and the piezoelectric element 7, and various specifications relating to the external terminals 3 can be met. Reduction is expected.

  In the piezoelectric device 1, the external terminal 3 is provided from the lower surface 11 b of the base substrate 5 to the lower surface 9 b of the expansion member 9.

  Therefore, the external terminal 3 has a large area as compared with the case where the external terminal 3 is provided only on the lower surface 11 b of the base substrate 5. Further, by ensuring a large area, the interval between the external terminals 3 is reduced, and the warp of the base substrate 5 caused by the force applied to the base substrate 5 via the external terminals 3 is suppressed. The warp of the functional surface 19a can be suppressed. By suppressing the warpage of the functional surface 19a, fluctuations in the electrical characteristics of the piezoelectric element 7 are suppressed.

  In the piezoelectric device 1, the expansion member 9 has a Young's modulus lower than that of the base substrate 5.

  Therefore, for example, the force applied to the external terminal 3 due to the warp of the mounting substrate on which the piezoelectric device 1 is mounted can be absorbed by the expansion member 9 and the force transmitted to the base substrate 5 can be reduced. As a result, the warp of the functional surface 19a of the piezoelectric element 7 is suppressed, and consequently the fluctuation of the electrical characteristics of the piezoelectric element 7 is suppressed.

  In the piezoelectric device 1, the expansion member 9 is disposed so as to surround the base substrate 5.

  Therefore, the area of the lower surface 9b of the expansion member 9 can be further secured, and the degree of freedom of design related to the external terminal 3 can be further improved. In addition, since the base substrate 5 is fitted to the expansion member 9, the fixing between the base substrate 5 and the expansion member 9 is also strong. As a result, the external terminals 3 provided on the expansion member 9 and the base substrate 5 are fixed. Connection reliability with the wiring is also improved.

  In the piezoelectric device 1, the expansion member 9 is joined to the side surface 19 c of the piezoelectric element 7.

  Therefore, the piezoelectric element 7 can be mechanically protected by the expansion member 9 that improves the degree of freedom of arrangement of the external terminals 3. As a result, both reduction in size and improvement in durability can be achieved. Further, since the expansion member 9 is disposed from the side surface 11c of the base substrate 5 to the side surface 19c of the piezoelectric element 7, the expansion member 9 forms the vibration space S and / or the vibration space S. It also contributes to suppression of moisture intrusion.

  In the piezoelectric device 1, the side surface 19 c of the piezoelectric element 7 and the side surface 11 c of the base substrate 5 are flush with each other.

  Therefore, the piezoelectric element 7 has a maximum area as long as it does not overlap with the expansion member 9. As a result, while suppressing the force applied to the expansion member 9 via the external terminal 3 from being applied to the piezoelectric element 7, the function of the piezoelectric element 7 is enhanced (in another aspect, the function of the piezoelectric element 7 is maintained). The size of the piezoelectric device 1 as a whole can be reduced). If attention is paid to the manufacturing process, the mother substrate 33 of the piezoelectric element 7 and the mother substrate 31 of the base substrate 5 can be cut at a time as described with reference to FIG. The efficiency of the manufacturing process is improved.

  In the present embodiment, the method for manufacturing the piezoelectric device 1 includes a step of preparing a mother substrate 31 including a plurality of base substrates 5 and a mother substrate 33 including a plurality of piezoelectric elements 7 (FIG. 3A). The mother substrates 31 and 33 are opposed to each other so that the plurality of piezoelectric elements 7 are face-down mounted on the plurality of base substrates 5, respectively, and the mother substrates 31 and 33 are connected to each other by the bumps 27 interposed between the opposed surfaces. Step (FIG. 3B) and step of forming the plurality of first pieces 8 including the base substrate 5 and the piezoelectric element 7 by cutting the connected mother substrates 31 and 33 (FIG. 3D) And including.

  Therefore, the process of picking up the plurality of separated piezoelectric elements 7 and mounting them on the mother board 31 of the base board 5 is replaced with the connection between the mother boards, and the productivity is improved. That is, as compared with the manufacturing method in which elements are mounted one by one as in Patent Document 1, if the manufacturing method according to the present embodiment, a plurality of elements can be simultaneously mounted. This is preferable because the manufacturing efficiency is improved. In addition, dicing tape, dicing blade, and the like can be shared by dividing the plurality of piezoelectric elements 7 into pieces and making the base substrate 5 into pieces. Such singulation is substantially premised on face-down mounting, and the piezoelectric element 7 forms a vibration space S between the functional surface 19a and the base substrate 5 by face-down mounting. Is possible. That is, such singulation is suitable for a method for manufacturing a piezoelectric device.

  In addition, the method for manufacturing the piezoelectric device 1 includes the step of forming the bonding substrate 40 in which the grooves 36 between the plurality of first pieces 8 are filled with the resin 39 and the plurality of first pieces 8 are bonded to each other (FIG. 4 (a)) and a step of forming a plurality of conductive layers (external terminals 3) respectively connected to the plurality of first pieces 8 on the surface of the bonding substrate 40 (FIG. 4D), The resin 39 in the groove 36 is cut to include the base substrate 5, the piezoelectric element 7, the expansion member 9 made of the cut resin 39 and bonded to the side surface 11 c of the base substrate 5, and a conductive layer (external terminal 3). Forming a plurality of second pieces (piezoelectric devices 1) (FIG. 4E).

  Therefore, the first piece 8 can be resin-sealed more easily than when the picked-up first piece 8 is resin-sealed. Furthermore, since the conductive layer (external terminal 3) is formed on the bonding substrate 40, the conductive layer can be provided on the expansion member 9, and compared with the case where the conductive layer is provided on the piece including the expansion member 9. Thus, a conductive layer can be easily provided.

  Moreover, the manufacturing method of the piezoelectric device 1 has a high degree of freedom in designing the external terminal 3 described above because the conductive layer is provided on the expansion member 9 and includes the external terminal 3 connected to the piezoelectric element 7. The piezoelectric device 1 can be realized.

  In the above embodiment, the base substrate 5 or the insulating base 11 is an example of the support member of the present invention.

(Second Embodiment)
FIG. 5 is a cross-sectional view corresponding to FIG. 2B, showing the piezoelectric device 201 of the second embodiment.

  The piezoelectric device 201 is different from the piezoelectric device 1 of the first embodiment only in the shapes of the sheet 229 and the external terminals 3. Specifically, it is as follows.

  The sheet 229 covers the same range as the sheet 29 of the first embodiment, and also covers the lower surface 9b of the expansion member 9. The external terminal 3 is provided on the lower surface 9 b of the expansion member 9 via the sheet 229. As described above, the sheet 229 can also be regarded as a part of the expansion member 9.

  Such a sheet 229 omits the step of removing the exposed portion of the sheet 37 from the resin 39 described with reference to FIG. 4C in the method of manufacturing the piezoelectric device 1 of the first embodiment. It is formed by.

  In the piezoelectric device 201, since the sheet 229 covers the lower surface 9b of the expansion member 9, for example, the sheet 229 is made of a material having high bondability with the external terminal 3, and the expansion member 9 has its Young It is possible to improve the reliability of the piezoelectric device 201 by using a material that is advantageous from the viewpoint of the thermal expansion coefficient and the thermal expansion coefficient. Moreover, in the manufacturing method of the piezoelectric device 201, since the process of FIG.4 (c) can be skipped, productivity improves more.

s
The external terminal 3 on the outer peripheral side of the piezoelectric device 201 extends on the lower surface 9b of the expansion member 9 until it reaches the side surface 1c of the expansion member 9, and the outer edge thereof coincides with the side surface 1c.

  Such an external terminal 3 can be formed by the patterning of the metal layer described with reference to FIG. 4D, as in the method of manufacturing the piezoelectric device 1 of the first embodiment. Unlike the first embodiment, in the patterning of the metal layer, the outer edge portion of the external terminal 3 is not patterned, and in the dicing of FIG. Thus, the outer edge of the external terminal 3 can be formed.

  And in the piezoelectric device 201, since the external terminal 3 has spread to the side surface 1c, the area of the external terminal 3 can be ensured to the maximum extent. Moreover, in the manufacturing method of the piezoelectric device 201, since dicing contributes to the patterning of the external terminal 3, it is possible to simplify the photomask, for example.

(Third embodiment)
FIG. 6 is a cross-sectional view corresponding to FIG. 2B showing the piezoelectric device 301 of the third embodiment.

  The piezoelectric device 301 is different from the piezoelectric device 1 of the first embodiment only in the expansion member 309. Specifically, it is as follows.

  First, unlike the first embodiment, the expansion member 309 does not cover the back surface 19b side of the piezoelectric element 7. The position of the upper surface 309 a of the expansion member 309 may be an appropriate position above the functional surface 19 a of the piezoelectric element 7. For example, the upper surface 309 a is flush with the back surface 19 b (strictly, the sheet 29) of the piezoelectric element 7.

  The expansion member 309 includes a first layer 308A bonded to the side surface 11c of the base substrate 5, and a second layer 308B stacked on the first layer 308A and bonded to the side surface 19c of the piezoelectric element 7. Yes. The boundary position between the first layer 308A and the second layer 308B may be an appropriate position between the upper surface 11a of the base substrate 5 and the functional surface 19a of the piezoelectric element 7.

  The first layer 308A and the second layer 308B are formed of different materials and exhibit different properties. For example, the first layer 308A has a thermal expansion coefficient closer to the base substrate 5 and / or the mounting substrate (not shown) than the second layer 308B, and the second layer 308B expands to the piezoelectric element 7 more than the first layer 308A. The coefficients are close. For example, the first layer 308A has a higher Young's modulus than the second layer 308B. The first layer 308A has a higher affinity for the material of the external terminal 3 than the second layer 308B.

  For example, in the step of supplying the resin described with reference to FIG. 4A, the first layer 308A and the second layer 308B become the second layer 308B and the step of supplying the resin to be the first layer 308A. It can be formed by sequentially performing the step of supplying the resin.

  Further, the position of the upper surface 309a of the expansion member 309 is set to an appropriate position by adjusting the amount of resin to be supplied. Note that the resin 39 on the back surface 19b side of the piezoelectric element 7 may be removed after the resin 39 is supplied.

  In the piezoelectric device 301 of the present embodiment described above, since the upper surface 309a of the expansion member 309 is positioned below the rear surface 19b of the piezoelectric element 7, it is thinner than the piezoelectric device 1 of the first embodiment. Figured. The piezoelectric device 1 according to the first embodiment is advantageous in terms of mechanical protection of the piezoelectric element 7 and the like.

  In the piezoelectric device 301, the expansion member 309 includes a first layer 308 </ b> A bonded to the side surface 11 c of the base substrate 5 and a second layer 308 </ b> B bonded to the side surface 19 c of the piezoelectric element 7 made of different materials. Therefore, as described above, the thermal stress can be alleviated as a whole, and the peeling of the external terminals 3 can be suppressed.

  In addition, the layer which comprises an expansion member is not limited to 2 types, Three or more types may be sufficient.

(Fourth embodiment)
FIG. 7 is a cross-sectional view corresponding to FIG. 2B, showing a piezoelectric device 401 of the fourth embodiment.

  The piezoelectric device 401 is different from the piezoelectric device 1 of the first embodiment only in the shape of the expansion member 409. Specifically, the position of the upper surface 409a of the expansion member 409 is further lower than that of the third embodiment (FIG. 6), and is set to be equal to or lower than the functional surface 19a or the upper surface 11a of the base substrate 5. .

  In the formation of the expansion member 409, as in the third embodiment, in the step of supplying the resin described with reference to FIG. 4A, the amount of the supplied resin is adjusted to adjust the upper surface. The position 409a is an appropriate position.

  In the piezoelectric device 401 of the present embodiment described above, the expansion member 409 is easily bent as compared to the piezoelectric device 1 of the first embodiment, and the force applied to the external terminal 3 is easily absorbed by the expansion member 409. Therefore, the warp of the base substrate 5 and the warp of the functional surface 19a are suppressed.

  The effect is also achieved in the third embodiment, although not as much as in the present embodiment. Moreover, since the expansion member 9 is located on the side of the vibration space S and the piezoelectric element 7 in the piezoelectric device 1 of the first embodiment, for example, the vibration space S is protected from moisture or the piezoelectric element 1 This is advantageous from the viewpoint of mechanically protecting 7 from the side.

(Fifth embodiment)
FIG. 8 is a cross-sectional view corresponding to FIG. 2B, showing the piezoelectric device 501 of the fifth embodiment.

  The piezoelectric device 501 is different from the piezoelectric device 1 of the first embodiment only in the shape of the expansion member 509, the arrangement of the external terminals 3, and the connection method between the external terminals 3 and the substrate pads 17. Specifically, it is as follows.

  The expansion member 509 covers not only the side surface 11c of the base substrate 505 but also the side surface 19c and the back surface 19b of the piezoelectric element 7 in the same manner as the expansion member 9 of the first embodiment. However, the expansion member 509 has a shape (a shape having a flange) in which the lower surface 509b side portion protrudes to the outer peripheral side. The position of the upper surface of the flange may be lower than the upper surface of the portion covering the back surface 19b, but preferably, the functional surface 19a or less of the piezoelectric element 7 is the same as in the fourth embodiment (FIG. 7). Alternatively, it is below the upper surface 11 a of the base substrate 5.

  Such an expansion member 509 is, for example, the dicing step shown in FIG. 4E after the supply of the resin 39 described with reference to FIG. 4A and before the dicing tape 35 shown in FIG. Can be formed by cutting the resin 39 in the groove 36 with a thicker dicing blade than the dicing blade used in FIG.

  In the piezoelectric device 501, the external terminal 3 on the outer peripheral side among the plurality of external terminals 3 is provided only on the lower surface 509 b of the expansion member 509 and does not overlap the lower surface 11 b of the base substrate 505. The external terminal 3 and the substrate pad 17 are connected by a side conductive layer 13 </ b> C provided on the side surface 11 c of the base substrate 505.

  Note that the side surface conductive layer 13C is formed, for example, by forming a via conductor or a through-hole conductor in advance at a position to be a dicing line in the production of the mother substrate 31 of the base substrate 5. Further, it may be formed on the side surface 11c of the insulating substrate 11 after the cutting described with reference to FIG.

  In the above-described piezoelectric device 501 of the present embodiment, the piezoelectric element 7 is mechanically protected from the side surface as in the first embodiment, and the external terminal 3 is bent by the expansion member 509 as in the fourth embodiment. Transmission of the applied force to the piezoelectric element 7 can be relaxed.

  Further, in the piezoelectric device 501, there are external terminals 3 provided only on the expansion member 509. Thus, the external terminals 3 provided using the expansion member 509 are provided from the expansion member to the base substrate. It is not limited to. That is, the present embodiment is an example showing that the degree of freedom in designing the external terminal 3 is high.

(Sixth embodiment)
FIG. 9A is a cross-sectional view corresponding to FIG. 2B showing the piezoelectric device 601 of the sixth embodiment, and FIG. 9B is an enlarged view of a region IXb in FIG. 9A. It is.

  The piezoelectric device 601 is different from the piezoelectric device 1 of the first embodiment only in the method for preventing the resin as an expansion member from entering the vibration space S. Specifically, it is as follows.

  The piezoelectric element 607 is configured as a wafer level package type piezoelectric element. Specifically, the piezoelectric element 607 has a configuration in which a cover 629 that covers the excitation electrode 21 is provided on the piezoelectric element 7 of the first embodiment.

  The cover 629 has a shape having a frame portion 629a that surrounds the excitation electrode 21 in a plan view of the functional surface 19a and a lid portion 629b that closes the opening of the frame portion. A vibration space S is configured by a space surrounded by the cover 629 and the functional surface 19a.

  The cover 629 is formed, for example, by forming a resin layer on the functional surface 19a and patterning it to form a frame portion 629a, and then superposing and patterning a resin sheet on the functional surface 19a to form a lid portion 629b.

  In the piezoelectric device 601, the cover 29 prevents the resin from entering the vibration space S, and thus the sheet 29 of the first embodiment is not provided. Therefore, the resin that becomes the expansion member 609 flows between the functional surface 19 a and the upper surface 11 a of the base substrate 5 to cover the cover 629 and the bump 27.

  The manufacturing method of the piezoelectric device 601 is the same as that of the first embodiment except that the manufacturing method of the piezoelectric element is different and the steps relating to the sheet of FIGS. 3E and 4C are omitted. This is the same as the manufacturing method of the piezoelectric device 1.

  Also in the piezoelectric device 601 of the present embodiment described above, since the external terminal 3 is provided on the lower surface 609b of the expansion member 609, the degree of freedom in designing the external terminal 3 can be improved as in the first embodiment. An effect is produced. In addition, since the expansion member 609 covers the bumps 27 and the like and also has a function of improving these insulating properties, it is expected that the expansion member 609 is reduced in size and improved in electrical reliability.

  The wafer level package type piezoelectric element may be provided with a columnar terminal that penetrates the frame of the cover and is exposed on the upper surface of the cover, or an opening formed in the frame and lid of the cover. The element pad may be exposed.

(Seventh embodiment)
FIG. 10A is a cross-sectional view corresponding to FIG. 2B showing the piezoelectric device 701 of the seventh embodiment, and FIG. 10B is a cross-sectional view taken along line Xb-Xb in FIG. It is sectional drawing (however, the expansion member 709 is abbreviate | omitted).

  The piezoelectric device 701 is different from the piezoelectric device 1 of the first embodiment only in the method for preventing the resin as an expansion member from entering the vibration space S. Specifically, it is as follows.

  In the piezoelectric device 701, a solder ring 729 is interposed between the base substrate 705 and the piezoelectric element 707. The solder ring 729 is formed in an annular shape surrounding the excitation electrode 21 and the bump 27 in a plan view. A vibration space S is formed by a region surrounded by the functional surface 19 a of the piezoelectric element 707, the upper surface 11 a of the base substrate 705, and the solder ring 729.

  The base substrate 705 and the piezoelectric element 707 are the same as the base substrate 5 and the piezoelectric element 7 of the first embodiment except that a space for providing the solder ring 729 is secured.

  For example, the solder ring 729 is formed in the same manner as the bump 27 at the same time as the formation of the bump 27. The manufacturing method of the piezoelectric device 701 is the same as that of the first embodiment except that the solder ring 729 is formed and the steps relating to the sheet of FIGS. 3E and 4C are omitted. This is the same as the manufacturing method of the piezoelectric device 1.

  Also in the piezoelectric device 701 of the present embodiment described above, since the external terminal 3 is provided on the lower surface 709b of the expansion member 709, the degree of freedom in designing the external terminal 3 can be improved as in the first embodiment. An effect is produced.

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

  Various features of the above-described embodiments may be appropriately combined. For example, the feature that the sheet of the second embodiment (FIG. 5) extends to the lower surface of the expansion member may be applied to the piezoelectric device of the third to fifth embodiments (FIGS. 6 to 8). However, the feature that the external terminal of the second embodiment extends to the side surface of the expansion member may be applied to the piezoelectric device of the third to seventh embodiments (FIGS. 6 to 10). The feature which comprises an expansion member from two or more types of layers (FIG. 6) of this embodiment may be applied to the fourth to seventh embodiments, or the third to fifth embodiments (FIG. 6 to FIG. 6). The feature of the shape and / or size of the expansion member of 8) may be applied to the sixth or seventh embodiment, and the external terminal of the fifth embodiment (FIG. 8) is provided only on the expansion member. The feature may be applied to all other embodiments.

  In any embodiment, the external terminal located only on the lower surface of the base substrate is provided, but the external terminal may not be provided. That is, the piezoelectric device may have only external terminals at least partially provided on the expansion member.

  The side surface of the piezoelectric element and the side surface of the support member need not be flush with each other. In this case, for example, in the dicing process described with reference to FIG. 3D, the piezoelectric element and the support member are first cut with a thin dicing blade, and then only the piezoelectric element is cut with a thick dicing blade. Thus, the side surface of the support member can be positioned outside the side surface of the piezoelectric element.

  The method for manufacturing the piezoelectric device may not include the steps after the step of supplying the resin to the first piece to form the expansion member. In other words, a piezoelectric device having no expansion member may be manufactured, or a piezoelectric device in which the expansion member is formed but the conductive layer is not formed on the expansion member may be manufactured. In this case, the external terminal may be formed on the mother board of the support member.

  In the step of dicing the mother substrate of the piezoelectric element and the mother substrate of the support member, the cutting may be performed from the mother substrate side of the support member, contrary to the embodiment. In this case, even if half-cutting is performed without performing full-cutting, it is possible to fill the groove with resin (expansion member) and form external terminals on the resin.

  The method for forming the expansion member is not limited to supplying the resin to the plurality of first pieces that are maintained in the state of being connected by the dicing tape. For example, a molten resin is supplied to the first piece picked up from the dicing tape by a transfer molding method, or an already molded (solidified) expansion member is fitted and / or bonded by an adhesive. You may do it.

  DESCRIPTION OF SYMBOLS 1 ... Piezoelectric device, 3 ... External terminal, 5 ... Base board | substrate (support member), 7 ... Piezoelectric element, 8 ... 1st piece, 9 ... Expansion member, 27 ... Bump, 31 ... Mother board, 33 ... Mother board.

Claims (4)

Preparing a mother board including a plurality of support members and a mother board including a plurality of piezoelectric elements;
Connecting the two mother substrates to each other by bumps interposed between the opposing surfaces so that the plurality of piezoelectric elements are face-down mounted on the plurality of support members, respectively. ,
Cutting the two mother substrates connected to form a plurality of first pieces including the support member and the piezoelectric element;
Filling a groove between the plurality of first pieces with a resin material to form a bonded substrate in which the plurality of first pieces are joined together;
Forming a plurality of conductive layers respectively connected to the plurality of first pieces on the surface of the bonding substrate;
A plurality of second members including the support member, the piezoelectric element, an expansion member made of the cut resin material and bonded to a side surface of the support member, and the conductive layer by cutting the resin material of the groove Forming a piece;
A method for manufacturing a piezoelectric device comprising: The method for manufacturing a piezoelectric device according to claim 1 , wherein the conductive layer includes an external terminal provided on the expansion member and connected to the piezoelectric element. Wherein in the plurality of steps of forming a first single piece, the two mother substrates the method for manufacturing a piezoelectric device according to claim 1 or 2 is cut together. A substrate-like support member;
A piezoelectric element having a piezoelectric substrate and face-down mounted on the support member by a bump interposed between a functional surface of the piezoelectric substrate and an upper surface of the support member;
An expansion member joined to the side surface of the support member and made of resin;
An external terminal provided on the lower surface of the expansion member and electrically connected to the support member;
Piezoelectric device with

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