JP2009183008A - Method of manufacturing piezoelectric component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric component which can be miniaturized and whose cost is reduced, and a method of manufacturing the same. <P>SOLUTION: A piezoelectric element 2 having a vibration part consisting of an IDT 2a formed on a piezoelectric substrate 2f and element wiring connected to the IDT 2a is provided. The piezoelectric element 2 and a joint substrate 1 are adhered to each other by a bump 3 and an insulating resin frame 4 so as to face the IDT 2a. The joint substrate 1 includes joint substrate wiring 1b on one main surface opposite to the IDT 2a, an external terminal 5 on the other main surface, and a through-hole 1a on a joint substrate edge, respectively. The bump 3 and the joint substrate wiring 1b of the joint substrate 1 are electrically connected to each other. The joint substrate wiring 1b and the external terminal 5 are electrically connected to each other via the through-hole 1a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a piezoelectric component that can be miniaturized and is preferably used in a communication device such as a mobile phone.

  Due to the recent reduction in size and weight of electronic devices, electronic components are also required to be multifunctional. In such a background, a surface acoustic wave filter (hereinafter referred to as a SAW filter) used as a surface acoustic wave device or a piezoelectric thin film resonator using a bulk wave of a piezoelectric body, which is used in a communication device such as a cellular phone, is used. Similarly, piezoelectric parts such as the piezoelectric filter (hereinafter referred to as BAW filter) are required to be reduced in size and weight.

  The BAW filter includes at least upper and lower surfaces of a Si substrate having an opening or a recess, and a thin film portion formed on the opening or the recess and having at least one piezoelectric thin film (made of ZnO or AlN). A piezoelectric resonator having a vibrating portion having a structure in which a pair of upper and lower electrodes are opposed to each other is configured in a ladder shape.

  In the BAW filter, since the thickness longitudinal vibration generated in the vibration part is used, it is necessary to secure a vibration space on the vibration part and to protect the vibration part from moisture and dust.

In the SAW filter, a plurality of pairs of interdigital transducers (interdigital transducer, hereinafter abbreviated as IDT) made of a metal such as Al are formed on a piezoelectric substrate such as quartz or LiTaO ₃ or LiNbO _3. It will be.

  In the SAW filter, it is necessary to secure a vibration space on a vibration portion such as a comb-shaped electrode portion or a surface acoustic wave propagation portion on a piezoelectric substrate, and to protect the comb-shaped electrode portion from moisture, dust, and the like.

  Therefore, the piezoelectric parts such as the conventional BAW filter and SAW filter are coated with a die-bonding agent on the bottom surface of the package made of alumina or the like, and the elements of the BAW filter or SAW filter are mounted on the package by die-bonding. After connecting the terminal of the element and the electrode of the element by wire bonding, it was sealed with a lid.

  In addition, in order to reduce the size of piezoelectric parts, an electrode land is formed on the bottom surface of a package made of alumina or the like, a BAW filter or SAW filter element is mounted on the package by flip chip bonding, and the package is sealed with a lid. Was also done.

  However, in such a structure, there is a problem that the piezoelectric component having the BAW filter or the SAW filter cannot be reduced in size or height unless the package is downsized when the elements of the BAW filter or the SAW filter are reduced in size. . There is also a problem that the cost for a small package is high.

  In particular, in the BAW filter, since the vibration part is formed on the opening or recess of the substrate, the vibration part is destroyed by an impact in processes such as element dicing, element pickup during mounting, die bonding, and the like. There was a problem that occurred.

  On the other hand, for example, in Patent Document 1, Patent Document 2, and Patent Document 3, mounting by bumps is performed. According to these publications, the SAW filter is miniaturized by eliminating the space necessary for wire bonding in flip chip mounting in which the SAW element is mounted by a bump formed on the base substrate (bonding substrate).

  However, it is necessary to form electrode pads for bumps in the SAW element, and the effective area of the SAW element is reduced, so that it is difficult to reduce the size. Moreover, the cost of bump formation is high.

  Therefore, in Patent Document 4, the SAW element is mounted on a base substrate (bonding substrate) in which a through hole facing the extraction electrode of the SAW element is formed, a metal film is formed in the through hole, and then a conductive material is filled. The external circuit connection part (external terminal) is formed. As a result, the SAW filter is downsized.

JP 2001-94390 A (published April 6, 2001) Japanese Patent Laid-Open No. 11-150441 (released on June 2, 1999) JP 2001-60642 A (published on March 6, 2001) Japanese Patent Laid-Open No. 2001-244785 (published September 7, 2001)

  However, in the configuration described in Patent Document 4, when forming the external circuit connection portion (external terminal), after forming a through hole in the base substrate (bonding substrate), a metal film is formed in the through hole. A plurality of processes such as filling a through hole with a conductive material is necessary, and the cost for manufacturing has been increased.

  In addition, since the external circuit connection portion (external terminal) is a cylindrical via hole, the area occupied by the external circuit connection portion (external terminal) with respect to the base substrate (bonding substrate) becomes large. There is a restriction on the wiring of the element, and thus there is an obstacle to miniaturization.

  In order to solve the above problems, the piezoelectric component of the present invention has a piezoelectric element having at least one vibrating portion formed on a substrate and a bonding substrate so that the vibrating portion faces the bonding substrate. A piezoelectric component that is bonded to each other by a bonding member and an insulating adhesive layer. The bonding substrate has a bonding substrate wiring on one main surface facing the vibration part, an external terminal on the other main surface, and a through terminal at the end of the bonding substrate. Each of the holes has a hole, and the bonding member and the bonding substrate wiring of the bonding substrate are electrically connected, and the bonding substrate wiring and the external terminal are electrically connected to each other through a through hole. .

  In the piezoelectric component, the bonding substrate wiring may have at least one of an inductance and a capacitance.

  In another piezoelectric component of the present invention, in order to solve the above-described problem, a piezoelectric element having at least one vibration part formed on a substrate and a bonding substrate are arranged so that the vibration part faces the bonding substrate. And a piezoelectric component bonded to each other by a bonding member and an insulating adhesive layer, wherein the bonding substrate has a multilayer structure, and the bonding substrate has bonding substrate wiring on one main surface facing the vibration part, An external terminal is provided on the other main surface, a through hole is provided at the end of the bonding substrate, and an internal wiring connected to the bonding substrate wiring and the through hole is provided inside. The bonding member and the bonding substrate wiring of the bonding substrate are electrically connected to each other. The connection board wiring and the external terminal are electrically connected to each other through an internal wiring and a through hole.

  In the piezoelectric component, at least one of the bonding substrate wiring and the internal wiring may have at least one of an inductance and a capacitance.

  In the piezoelectric component, the adhesive layer may be formed along an outer edge portion of the substrate on which at least one vibration portion is formed.

  In the above piezoelectric component, the piezoelectric element may be a surface acoustic wave element having a piezoelectric substrate and a vibrating portion including at least one comb-shaped electrode portion formed on the piezoelectric substrate.

  In the above piezoelectric component, the piezoelectric element has at least a pair of upper and lower electrodes facing a substrate having an opening or a recess and at least one upper and lower surfaces of the piezoelectric thin film formed on the opening or the recess. A piezoelectric thin film resonator having a vibrating portion sandwiched between them may be used.

  In order to solve the above-described problems, a communication device according to the present invention includes any one of the piezoelectric components described above.

  In order to solve the above-described problems, the piezoelectric component manufacturing method of the present invention is configured such that a piezoelectric element having at least one vibration part formed on a substrate and a bonding substrate are disposed so that the vibration part faces the bonding substrate. And a method of manufacturing a piezoelectric component bonded to each other by a metal bump and an insulating resin layer, wherein the metal bump is provided with a low melting point metal on the front end side and a high melting point metal having a melting point higher than that of the low melting point metal on the base end side. The multilayer structure is formed on one of the piezoelectric element and the bonding substrate, the height of the resin layer is lower than the height of the metal bump, and is formed on one of the piezoelectric element and the bonding substrate, and the piezoelectric element and the bonding substrate are bonded to each other. It is characterized by that.

  In the said manufacturing method, it is preferable to form the height of a resin layer higher than the height of the refractory metal of a metal bump.

  In another method of manufacturing a piezoelectric component according to the present invention, in order to solve the above-mentioned problem, a step of obtaining a collective element substrate by forming a plurality of piezoelectric elements having at least one vibration part formed on the collective substrate; Forming an insulating resin layer and metal bumps along the outer edge line of each piezoelectric element on one of the collective element substrate and the collective junction board, and the assembly so that the vibration part faces the collective junction board A step of bonding the element substrate and the collective bonding substrate to each other by an insulating resin layer and a metal bump, and a step of dividing the collective element substrate and the collective bonding substrate along the resin layer to obtain individual piezoelectric components It is characterized by.

  In the manufacturing method, the step of forming a metal bump in a multilayer structure having a low melting point metal on the front end side and a high melting point metal having a melting point higher than that of the low melting point metal on the base end side, and the height of the resin layer And a step of forming the metal bump lower than the height of the metal bump. In the said manufacturing method, it is preferable to form the height of a resin layer higher than the height of the refractory metal of a metal bump.

  As described above, in the piezoelectric component of the present invention, the bonding substrate includes the bonding substrate wiring on one main surface facing the vibration portion, the external terminal on the other main surface, and the through hole at the end of the bonding substrate, respectively. And the bonding substrate wiring of the bonding substrate are electrically connected, and the bonding substrate wiring and the external terminal are electrically connected to each other through a through hole.

  Therefore, in the above configuration, since the through hole is formed at the end portion of the bonded substrate, the area required for the through hole is reduced and the size can be reduced.

  In the configuration in which the adhesive layer is formed along the outer edge portion of the substrate on which at least one vibration part is formed, the adhesive layer (resin frame made of an insulator formed along the outer periphery of the substrate of the piezoelectric element) ), The bumps are not crushed more than necessary at the time of joining, and the vibration space of the piezoelectric element can be ensured reliably.

  In the manufacturing method, a metal bump is formed on one of the piezoelectric element and the bonding substrate in a multilayer structure having a low melting point metal on the front end side and a high melting point metal having a melting point higher than the low melting point metal on the base end side, and a resin layer Is formed on one of the piezoelectric element and the bonding substrate lower than the height of the metal bump, and the piezoelectric element and the bonding substrate are bonded to each other.

  Therefore, in the above method, by setting the height of the resin layer to be lower than the height of the metal bumps, the bumps are not crushed more than necessary at the time of bonding, and the vibration space of the piezoelectric element can be reliably ensured.

  Also, in the method using the collective substrate, metal bumps and the like are formed and bonded to each other while the bonded substrate is in the collective substrate state and the piezoelectric element is in the wafer state, and then dicing into individual piezoelectric components. Can be simplified, and the cost can be reduced.

1 is an exploded perspective view showing a first embodiment of a piezoelectric component according to the present invention. The piezoelectric component of the said 1st embodiment is shown, (a) is a top view, (b) is a front view. It is a block diagram of each IDT of the piezoelectric element of the said piezoelectric component. It is a top view of the piezoelectric substrate which formed each surface acoustic wave resonator and a part of routing wiring. It is a top view of the junction board in which junction board wiring which has a capacitor and an inductor was formed. FIG. 6 is a perspective view of a piezoelectric component obtained by bonding the piezoelectric substrate of FIG. 4 and the bonding substrate of FIG. 5. It is sectional drawing of the multilayer board | substrate used for the joining board | substrate as another modification which concerns on the said 1st Embodiment. It is a circuit diagram which shows 2nd Embodiment based on the piezoelectric component of this invention. It is a top view of the piezoelectric element of the second embodiment. FIG. 5 is a cross-sectional view showing a step of the manufacturing method of the second embodiment, showing a step of bonding and bonding each collective bonding substrate by thermocompression bonding on both surfaces of the collective silicon substrate provided with each matrix-like resin frame. is there.

  The following describes embodiments of the piezoelectric component according to the present invention with reference to FIGS. 1 to 10.

(First embodiment)
As shown in FIGS. 1 and 2, in a piezoelectric component, a bonding substrate 1 and a piezoelectric element 2 which is a surface acoustic wave filter element (SAW filter) are composed of a bump (metal bump) 3 and an insulating resin frame ( Resin layer 4 is bonded to each other. In the piezoelectric component, the vibration part made of IDT 2a is formed to face the bonding substrate 1 with a gap. The resin frame 4 is formed so as to surround the IDT 2a so as not to inhibit the vibration of the IDT 2a. The cross-sectional shape of the resin frame 4 in the surface direction of the piezoelectric substrate 2f is preferably a closed curve in order to ensure the sealing performance to the IDT 2a, and is formed along the outer edge of the piezoelectric substrate 2f. It is more desirable.

  The piezoelectric element 2 has at least one IDT 2a. Specifically, as shown in FIG. 3, the element wiring 2b connected to the surface acoustic wave resonators 2aa to 2ae having the IDT 2a, and the element wiring The electrode pads 2c to 2e connected to 2b are respectively formed on the piezoelectric substrate (substrate) 2f. In the first embodiment, each of the five surface acoustic wave resonators 2aa to 2ae is arranged so as to be a ladder type, thereby forming a surface acoustic wave filter element.

  As shown in FIG. 1, the bonding substrate 1 is made of any one of a glass substrate, a polyimide substrate, and an alumina substrate. A through-hole 1a is formed on the side surface of the bonding substrate 1, and a bonding substrate wiring is formed on one main surface facing the IDT 2a. 1b and an external terminal 5 on the other main surface not facing the IDT 2a. Therefore, the cross-sectional shape in the surface direction of the bonding substrate 1 in the through hole 1a is substantially semicircular at the side and quadrant (fan shape) at the corner, and from the external terminal 5 side, the resin frame 4 passes through the through hole 1a. A part of is exposed.

  The bumps 3 and the bonding substrate wiring 1b of the bonding substrate 1 are electrically connected. The bonding substrate wiring 1b and the external terminal 5 are electrically connected to each other through the through hole 1a. Therefore, on the surface of the through hole 1a, a conductive metal thin film such as Au electrically connects the corresponding bonding substrate wiring 1b and the external terminal 5 to each other on the wall surface of the through hole 1a. Is formed.

Next, a method for manufacturing a piezoelectric component according to the present invention will be described. First, an Al electrode is formed on an aggregate piezoelectric substrate made of a LiTaO ₃ substrate having a thickness of 0.35 mm · 100 mmφ and a resistivity of 1.0 × 10 ⁹ Ω · cm to 1.0 × 10 ¹³ Ω · cm. A plurality of surface acoustic wave resonators 2aa to 2ae and a plurality of electrode pads 2c to 2e are formed corresponding to each chip-like piezoelectric component by a lift-off method by vapor deposition. The alignment mark is also formed on the collective piezoelectric substrate simultaneously in the same process.

  Thereafter, bumps 3 are formed on the electrode pads 2c to 2e in a columnar shape or a prismatic shape using a lift-off technique. As the bump 3, a multilayer structure of Sn (3 μm) / Cu (10 μm) / Ti (0.1 μm) is used from the tip side of the bump 3 on the electrode pad made of Al.

  Subsequently, a resin frame is formed on the aggregated piezoelectric substrate in a matrix shape (lattice shape) of photosensitive polyimide and having a height of 11 μm and a width of 100 μm (in the case of one piezoelectric element, a width of 50 μm), which is lower than the height of the bump 3. Are formed corresponding to each piezoelectric element 2.

  On the other hand, a collective bonding substrate made of a glass substrate having a thickness of 50 μm / 100 mmΦ, a polyimide substrate, or an alumina substrate is prepared. A through hole having a diameter of 60 μm smaller than the width of the matrix-shaped resin frame is formed coaxially with respect to the center line in a portion of the collective bonding substrate facing the center line of the matrix-shaped resin frame formed as described above. Regarding the formation of the through hole, in the case of a glass substrate, dry etching and wet etching are combined, and in the case of a polyimide substrate and an alumina substrate, it is formed by laser processing. The center line is a center line in the width direction of the matrix-like resin frame.

  Thereafter, Au is formed on the entire surface of the collective bonding substrate having through holes by electroless plating to a thickness of 0.1 μm, and a desired resist pattern is formed on the Au. Au is removed by wet etching. The portions where Au is left are the portion of the external terminal 5, the side wall of the through hole, the lead-out wiring (bonding substrate wiring), and the bump electrode pads (bonding substrate wiring).

  In some cases, in order to improve the bonding reliability of the collective bonding substrate, the surface of the collective bonding substrate on which the through-holes are formed is provided with a matrix of photosensitive polyimide on the surface on which the bump electrode pads are formed. A resin frame (thickness 13 μm, width 100 μm) may be formed.

Next, alignment is performed with reference to the alignment mark, the collective piezoelectric substrate made of LiTaO ₃ and the collective bonding substrate are bonded to each other, and mechanically bonded to each other by thermocompression bonding using a matrix-like resin frame. To do. At this time, the set temperature of thermocompression bonding is set to a temperature not lower than the melting point of Sn (232 ° C.) and lower than the melting point of copper (1083 ° C.), and mechanical and electrical connection by the bumps 3 is simultaneously performed.

Thereafter, a buffering resin is applied to the back surface of the collective piezoelectric substrate and cured, and finally, the piezoelectric parts are separated and completed by dicing along the center line of the matrix-shaped resin frame. When the final dicing is completed, the cutting allowance is 35μm by dicing with an electroformed blade.
Therefore, the sealing width of the resin frame 4 obtained by dividing the matrix-shaped resin frame along the center line can be sufficiently secured.

  In the configuration and method of the present invention, since the through hole 1a is provided at the edge of the bonding substrate 1 made of any one of a glass substrate, a polyimide substrate, and an alumina substrate, the effective area that can be wired on the bonding substrate 1 can be increased. In addition, since the arrangement of the through hole 1a is avoided in the vibration portion made of the IDT 2a, the effective area of the piezoelectric substrate 2f can be increased.

  Further, in the above method, the bonding substrate wiring 1b such as the lead wiring and the electrode pad for pumping, the side wall of the through hole 1a, and the external terminal 5 are formed at a time, so that the cost can be reduced and the resin frame is formed from the diameter of the through hole 1a. By setting the width large, it is possible to secure the sealing performance by the resin frame 4 obtained by dividing the matrix-shaped resin frame.

  Further, in the configuration and method of the present invention, the bump cost formed by lift-off can be reduced to a bump cost as compared with the case of using Au / Sn / Cu. The multilayer structure of the bump 3 only needs to have a low melting point metal such as Sn and a high melting point metal having a higher melting point than the low melting point metal such as Cu. Cu is a material that increases the melting point of the Sn alloy by diffusing into Sn, and is characterized by being inexpensive. By adopting such a multilayer structure, the melting point of the metal in the joined portion after joining can be made larger than that before joining, and the heat resistance can be improved. Further, instead of Cu, Au or Ag is also possible.

  As a preferable structure of the bump formed by lift-off, since Al easily penetrates into Sn and diffuses, NiCr (or Ni) is inserted between Al wiring and Cu in order to prevent diffusion of Al into Sn. May be. That is, as an example of the structure of the piezoelectric element on which the optimal bump 3 is formed, Sn / Cu / Ni / Ti / Al wiring / piezoelectric substrate can be mentioned. In reality, it is desirable that the bump electrode pad on the side of the bonding substrate 1 that receives the bumps 3 is also a Cu / Ni / Ti / bonding substrate. Ti is an adhesion layer for ensuring adhesion to the electrode pads 2c to 2e and the piezoelectric substrate.

  In addition, since a matrix-like resin frame slightly shorter than the bump 3 is provided, the Sn of the bump 3 melts and protrudes when the collective bonded substrate and the collective piezoelectric substrate are bonded, that is, the shape of the bump 3 is collapsed. Can be avoided. Therefore, the bumps 3 that electrically and mechanically join the collective bonding substrate and the collective piezoelectric substrate become columnar, and the above-mentioned bonding can be maintained at a desired strength, and the vibration space of the vibration part can be secured.

In the above configuration and method, the piezoelectric component obtained by using the piezoelectric substrate 2f having a resistivity of 1.0 × 10 ⁹ Ω · cm to 1.0 × 10 ¹³ Ω · cm and low pyroelectricity. Can improve reliability.

That is, in the conventional LiTaO ₃ substrate, pyroelectric breakdown of the electrode due to temperature change during the manufacturing process occurs, so that all the electrodes are connected to the same potential as described in JP-A-5-267971. The process of carrying out etc. was required.

On the other hand, as described above, by using the piezoelectric substrate 2f of LiTaO ₃ having a resistivity of 1.0 × 10 ⁹ Ω · cm to 1.0 × 10 ¹³ Ω · cm and low pyroelectricity, as described above. Thus, a ground line for protecting the electrode from pyroelectric breakdown that occurs during manufacturing can be omitted, and the ground line is not exposed on the side surface of the package, thereby ensuring reliability.

Further, in the above-described configuration and method, the thermocompression bonding of the bonding substrate and the connection of the bumps 3 by the matrix-shaped resin frame can be performed at the same time. By joining them together in this state and then forming individual piezoelectric parts by dicing, the manufacturing process can be simplified and the cost can be reduced.

  In addition, in the above configuration and method, since the cutting is performed by dicing along the center line of the matrix-shaped resin frame, the matrix-shaped resin frame is also divided so that the matrix-shaped resin frame also functions as a cushioning material. Thus, damage to the bonding substrate 1 and the piezoelectric substrate 2f can be suppressed by the division.

Further, as shown in FIG. 4, only a part of the routing wiring 1c is formed on the substrate of the piezoelectric element 2, and as shown in FIGS. 5 and 6, the remaining routing wiring is used as the bonding substrate wiring 1b. 1 may be formed. As a result, since the dielectric constant of LiTaO ₃ or LiNbO ₃ is high, it is possible to prevent the generation of parasitic capacitance that occurs at locations where wirings having different potentials face each other. Capacitors 6a and 6b and inductors 7a to 7c may be provided as part of the bonding substrate wiring 1b. The capacitors 6a and 6b and the inductors 7a to 7c are connected to the surface acoustic wave resonators 2aa to 2ae by the bumps 3, and are connected to the external terminals 5a to 5e by the bonding substrate wirings 1b.

  As a modification of the first embodiment, as shown in FIG. 7, the bonding substrate 1 may be a ceramic multilayer substrate or a resin multilayer substrate. At this time, the electrode 1d of the through hole 1a is formed halfway in the thickness direction of the bonding substrate 1, and is connected to the internal wiring 1e in the multilayer substrate from there and connected to the bonding substrate wiring 1b through the internal wiring 1e. Also good. When such a ceramic multilayer substrate or a resin multilayer substrate is used as the bonding substrate 1, there is an advantage that an inductor (L) or a capacitor (C) can be formed in the bonding substrate 1.

  In the first embodiment, the example in which the bump 3 is used as a bonding member has been described. However, the present invention is not limited to the above example. For example, a conductive adhesive may be used instead of the bump 3. it can.

(Second embodiment)
In the piezoelectric component according to the second embodiment, as shown in FIGS. 8 and 9, each of the piezoelectric thin film resonators 12a and 12b is replaced with a ladder instead of the surface acoustic wave filter element described in the first embodiment. A piezoelectric thin film element that is disposed in a mold and serves as a piezoelectric thin film filter (BAW filter) is formed as the piezoelectric element 2. 8 and 9, the series-side piezoelectric thin film resonator is indicated by 12a, and the parallel-side piezoelectric thin film resonator is indicated by 12b. In the second embodiment, members having the same functions as those in the first embodiment are given the same member numbers and are not described.

  As shown in FIGS. 9 and 10, the piezoelectric thin film resonator 12 has a piezoelectric thin film 12 c made of zinc oxide (ZnO), aluminum nitride (AlN), or the like placed on the opening 14 c of the support substrate 14 made of silicon. A lower electrode 12d and an upper electrode 12e are formed to be sandwiched from the direction of the thickness of the piezoelectric thin film 12c.

A method for manufacturing a piezoelectric component according to the second embodiment will be described below. First, a layer made of any one of SiO ₂ , AlN, Al ₂ O ₃ or a layer made by laminating any one of AlN, Al ₂ O ₃ , SiO ₂ on both surfaces of the support substrate 14 made of silicon, etc. Each insulating film 14a, 14b is formed.

Further, an opening (cavity) 14 c that penetrates in the thickness direction of the support substrate 14 and reaches the insulating film 14 a is formed in the support substrate 14. Further, on the insulating film 14a at the position facing the opening 14c, a lower electrode (electrode) 12d made of Al or the like, a piezoelectric thin film 12c made of ZnO or AlN, or the like, and an upper electrode (electrode) 12e made of Al or the like in this order. Are stacked on each other in the thickness direction.

  The insulating film 14a forms a diaphragm on the opening 14c. Therefore, each piezoelectric thin film resonator 12 has a structure in which an upper and lower surfaces of a thin film portion having at least one piezoelectric thin film are sandwiched between at least a pair of lower electrodes and upper electrodes on the diaphragm.

  In the configuration of the second embodiment, when four piezoelectric thin film resonators 12 are arranged in a ladder shape, the upper electrode and a part of the lower electrode of each piezoelectric thin film resonator 12a, 12b on the input side are shared. By doing so, it is possible to reduce the size of the routing wiring.

  In the manufacturing method of the second embodiment, as shown in FIG. 10, as in the first embodiment, piezoelectric elements that are a plurality of piezoelectric thin film filters on a wafer-sized aggregate silicon substrate 14d. 2 are formed adjacent to each other in a grid pattern, and then bumps 3 are formed on the piezoelectric element 2. Then, matrix-like resin frames 24 similar to those in the first embodiment are formed on both surfaces of the collective silicon substrate 14d along the boundary lines and the outer edge lines of the piezoelectric elements 2, respectively.

  Subsequently, the respective collective bonded substrates 11 and 21 are bonded and bonded to both surfaces of the collective silicon substrate 14d provided with the matrix-like resin frames 24 by thermocompression bonding. At this time, a through-hole 1 a is formed at a position on the boundary line of the piezoelectric element 2 in one collective bonding substrate 21 facing the upper electrode 12 e of the piezoelectric thin film resonator 12. An external terminal 5 is formed on the peripheral surface of one of the through holes of the through-hole 1a in the collective bonding substrate 21 (the surface opposite to the surface facing the upper electrode 12e of the piezoelectric thin film resonator 12). On the surface of the other side (the surface facing the upper electrode 12e of the piezoelectric thin film resonator 12) of the collective bonding substrate 21, a bonding substrate wiring 1b electrically connected to the external terminal 5 is formed.

  The collective silicon substrate 14d to which the collective bonding substrates 11 and 21 are bonded in this way is the center line of each matrix-like resin frame 24 (virtual line A in FIG. 10), as in the first embodiment. Are divided by dicing, and individual piezoelectric parts are obtained.

  Therefore, the piezoelectric component is obtained by dividing the collective silicon substrate 14 d and bonding substrates are bonded to both surfaces of the support substrate 14 by the resin frames 24. Each of the bonding substrates is formed by dividing the collective bonding substrates 11 and 21. Further, the resin frame 24 secures a space for vibration on the upper electrode 12 e of the piezoelectric thin film resonator 12.

  Also in the second embodiment, as in the first embodiment, by forming the through hole 1a along the outer edge of the piezoelectric component, the area of the through hole 1a can be reduced, and each bonding substrate Wiring can be formed on the whole to reduce the size and cost.

  In each of the embodiments described above, the bump electrode pad is formed. However, it is also possible to make the lead-out wiring of the piezoelectric element 2 thick and use the electrode pad as the electrode pad without providing the electrode pad. .

  Further, in the above, the resin frames 4 and 24 are formed of photosensitive polyimide, but other than this, any insulating material that can be patterned may be used. Specifically, a glass sealing material (printed at about 350 ° C.) Can be hermetically sealed), and photosensitive benzocyclobutene (BCB).

  In addition, in each of the above embodiments, the bonding substrates 1, 11, and 21 to be attached are polyimide bases or glass substrates, but any other insulating substrate such as an alumina substrate may be used.

  A glass substrate or an alumina substrate can be hermetically sealed by applying a glass sealing material as a sealing material. In addition, since the glass substrate is transparent, the alignment at the time of bonding may be facilitated.

  Some glass substrates are thin (30 μm or 50 μm) and are not easily broken, which is advantageous for thinning the piezoelectric component itself and reducing the diameter of the through hole, and allows the through holes to be formed in a lump. When a polyimide substrate is used, hermetic sealing cannot be performed, but bonding can be facilitated.

  The piezoelectric component and the manufacturing method thereof according to the present invention can be suitably used in the field of communication devices such as mobile phones because SAW filters and BAW filters can be reduced in size and cost.

DESCRIPTION OF SYMBOLS 1 Bonding board 1a Through hole 1b Bonding board wiring 2 Piezoelectric element 2a IDT (vibration part)
2f Piezoelectric substrate 3 Bump (metal bump)
4 Resin frame (resin layer)
5 External terminal

Claims (5)

Piezoelectric component manufacturing method in which a piezoelectric element having at least one vibration part formed on a substrate and a bonding substrate are bonded to each other by a metal bump and an insulating resin layer so that the vibration part faces the bonding substrate Because
A metal bump is formed on one of the piezoelectric element and the bonding substrate in a multilayer structure having a low melting point metal on the front end side and a high melting point metal having a melting point higher than the low melting point metal on the base end side,
The height of the resin layer is lower than the height of the metal bumps and formed on one of the piezoelectric element and the bonding substrate,
A method for manufacturing a piezoelectric component, comprising bonding a piezoelectric element and a bonding substrate to each other.   2. The method of manufacturing a piezoelectric component according to claim 1, wherein the height of the resin layer is formed higher than the height of the refractory metal of the metal bump. Forming a plurality of piezoelectric elements having at least one vibrating portion on the aggregate substrate to obtain an aggregate element substrate;
Forming an insulating resin layer along the outer edge line of each of the piezoelectric elements and a metal bump on one of the collective element substrate and the collective bonding substrate;
Bonding the collective element substrate and the collective bond substrate to each other with an insulating resin layer and metal bumps so that the vibration part faces the collective bond substrate;
And a step of dividing the assembly element substrate and the assembly bonding substrate along the resin layer to obtain individual piezoelectric components. Furthermore, forming a metal bump in a multilayer structure having a low melting point metal on the front end side and a high melting point metal having a melting point higher than that of the low melting point metal on the base end side;
The method of manufacturing a piezoelectric component according to claim 3, further comprising: forming a height of the resin layer lower than a height of the metal bump.   5. The method of manufacturing a piezoelectric component according to claim 4, wherein the height of the resin layer is higher than the height of the refractory metal of the metal bump.

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