JP2006197413A - Thin film piezoelectric element, thin film piezoelectric resonator and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric resonant element and a thin film piezoelectric resonator which are provided with a new electrode connection structure and are excellent in characteristics and whose miniaturization and light weightness can be realized, and a manufacturing method for them. <P>SOLUTION: The thin film piezoelectric resonant element 1 and the thin film piezoelectric resonator are provided with a board 2, a first electrode 31 disposed in a first area A on the front face of the board 2, an extraction electrode 32 disposed in a second area B different from the first area A on the front face of the board 2, one end of which is electrically connected to the first electrode 31 and the other end of which is formed so as to be extracted from the rear face of the board 2, a piezoelectric material thin film 4 disposed on the first electrode 31, a second electrode 5 on the piezoelectric material thin film 4, and a cavity 21 for resonance disposed in the board 2 at the part where the first electrode 31 is disposed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thin film piezoelectric resonator, a thin film piezoelectric resonator, and a method of manufacturing the same, and more particularly, a thin film piezoelectric resonator having a piezoelectric thin film on a substrate, a thin film piezoelectric resonator having the thin film piezoelectric resonator mounted thereon, and their It relates to a manufacturing method.

  In recent years, wireless radio technology has made remarkable progress, and further development aimed at high-speed transmission of information has been continued. In these wireless communication technologies, with the introduction of PHS systems, third generation mobile communication, wireless LAN, etc., the frequency band around 2 GHz tends to be widely used in the market, and the number of subscribers, the number of terminals, etc. are dramatic. It is increasing. For the purpose of speeding up the amount of information transmission, the frequency of the carrier wave itself tends to be higher, and in the wireless LAN system, commercialization has been started up to a frequency band of 5 GHz.

  There is a strong demand for miniaturization and weight reduction for communication devices using these high frequency bands. In particular, in personal computer (PC) applications, there is a great demand for using communication devices as PC cards, and PC cards need to be manufactured as thin as several millimeters.

  A wireless device used as a PC card generally includes an RF front end unit that processes high frequency (RF) and a baseband (BB) unit that performs digital signal processing. The baseband portion is a portion that performs signal modulation and demodulation in digital signal processing. Since this baseband portion can be basically constituted by an LSI chip based on a silicon (Si) substrate, it can be easily made thin to 1 mm or less.

  On the other hand, the RF front end unit is a part that performs amplification, frequency conversion, and the like using a high frequency signal as an analog signal. Therefore, it is technically difficult to configure the RF front end unit only with an LSI chip, and the RF front end unit has a complicated configuration including many passive components such as an oscillator and a filter. Of the passive components, a dielectric filter or an LC filter is used as the filter. In these filters, since the high-frequency signal is filtered by using the passband characteristics of the cavity resonator and the LC circuit, it is essentially difficult to reduce the size, and it is extremely difficult to reduce the thickness to several millimeters or less. In other words, there has been a limit to reducing the size and thickness of communication devices that use a high frequency band.

  As a technique for solving this type of problem, for example, a thin film piezoelectric resonator (FBAR: film bulk acoustic wave resonator) disclosed in Patent Document 1 below has been attracting attention. As shown in FIG. 13, a thin film piezoelectric resonator 100 includes a piezoelectric thin film 103 made of aluminum nitride (AlN) or zinc oxide (ZnO) sandwiched between two lower electrodes 102 and an upper electrode 104. A body thin film 103 is provided on a cavity 101H formed on the substrate 101 on the substrate 101. This thin film piezoelectric resonator 100 obtains frequency resonance in the thickness direction in which the lower electrode 102 and the upper electrode 104 in contact with the air layer and the piezoelectric thin film 103 are combined. A thickness of 0.5 μm to several μm, which can be easily manufactured in the film formation technique, corresponds to a frequency of several GHz, and a high-frequency resonator in the GHz band can be easily manufactured.

  The thin film piezoelectric resonator 100 can be constructed as a ladder-type bandpass filter by connecting two in series and connecting one in parallel. In the band pass filter, the center frequency of both the series connection and the parallel connection of the thin film piezoelectric resonator 100 is slightly changed. For example, the latter anti-resonance frequency is adjusted to coincide with the former resonance frequency. .

Since such a thin film piezoelectric resonator 100 can be manufactured by a film forming technique for forming a thin film on the substrate 101, it can be easily reduced in size, particularly in a general filter. It is possible to easily realize a thickness of 1 mm or less, which is difficult to do. In addition, since the thin film piezoelectric resonator 100 can use a Si substrate as the substrate 101 and can be manufactured by using a semiconductor manufacturing technique, it is highly compatible with transistors, ICs, LSIs, etc. Can be easily implemented.
JP 2000-69594 A

  However, in the above-described thin film piezoelectric resonator 100, the following points have not been considered. When a high-frequency module is constructed by mounting together with amplifying elements such as transistors, ICs, LSIs, or capacitors, resistors, inductors, etc., in order to make electrical connection with these other elements, the aforementioned FIG. The electrode pad 105 is required for the lower electrode 102 and the electrode pad 106 is required for the upper electrode 104 of the thin film piezoelectric resonator 100 shown in FIG. Since the upper electrode 104 has a structure exposed on the surface, the connection between the electrode pad 106 and the upper electrode 104 is easy. However, since the lower electrode 102 has a structure sandwiched between the substrate 101 and the piezoelectric thin film 103, a piezoelectric body on a part of the lower electrode 102 is used for connection between the lower electrode 102 and the electrode pad 105. It is necessary to remove the thin film 103 and expose a part of the lower electrode 102. A vapor phase etching (RIE) method can be used to remove the piezoelectric thin film 103.

  However, since AlN used as the piezoelectric thin film 103 is a material that is difficult to etch, the vapor-phase etching rate cannot be increased. That is, at the time of vapor phase etching, the patterning resist mask is retracted at a high speed, the resist mask disappears during vapor phase etching of the thick piezoelectric thin film 103 of about several μm, and the surface of the piezoelectric thin film 103 is exposed. . Furthermore, since the etching rate selection ratio between the piezoelectric thin film 103 and the lower electrode 102 cannot be increased in the vapor phase etching, the lower electrode 102 is pierced by overetching of the piezoelectric thin film 103. Further, in the thin film piezoelectric resonator 100, deterioration of characteristics due to adsorption of oxygen and moisture to the etched surface occurs, flatness of the fork surface structure is lost, and variations in characteristics occur during mounting.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a thin-film piezoelectric resonator element having a new electrode connection structure, excellent characteristics, and capable of realizing a reduction in size and weight. And a thin film piezoelectric resonator.

  The objective of this invention is providing the manufacturing method of the thin film piezoelectric resonator element and thin film piezoelectric resonator which can eliminate the malfunction resulting from the etching of a piezoelectric thin film.

  A first feature according to an embodiment of the present invention is that in a thin film piezoelectric resonant element, a substrate, a first electrode disposed in a first region on the substrate surface, and a first region on the substrate surface A lead electrode disposed in a second region different from the first electrode, wherein one end is electrically connected to the first electrode and the other end is drawn from the back surface of the substrate; and on the first electrode A piezoelectric thin film disposed, a second electrode on the piezoelectric thin film, and a resonance cavity disposed in the substrate at a portion where the first electrode is disposed.

  A second feature according to the embodiment of the present invention is that the thin film piezoelectric resonator further includes a mounting substrate and a solder electrode on the mounting substrate, the mounting substrate surface and the back surface of the thin film piezoelectric resonator element. Are mounted on the mounting substrate, and the solder electrode and the back surface of the extraction electrode of the thin film piezoelectric resonator are electrically connected.

  A third feature according to the embodiment of the present invention is that the thin film piezoelectric resonator further includes a mounting substrate, and the surface of the mounting substrate and the surface of the thin film piezoelectric resonator element face each other on the mounting substrate. A piezoelectric resonant element is mounted, and a wire is electrically connected to the back surface of the extraction electrode of the thin film piezoelectric resonant element.

  According to a fourth aspect of the present invention, in the method for manufacturing a thin film piezoelectric resonator, the first electrode is formed in the first region on the substrate surface, and the first region on the substrate surface is Forming a lead electrode connected to the first electrode in different second regions, forming a piezoelectric thin film on the first electrode, and forming a second electrode on the piezoelectric thin film And a step of forming a connection cavity in the substrate at the portion where the extraction electrode is formed, and a step of forming a resonance cavity in the substrate at the portion where the first electrode is formed.

  According to a fifth feature of the present invention, in the method of manufacturing a thin film piezoelectric resonator, a step of forming a solder electrode on the mounting substrate, a mounting substrate surface, and a substrate back surface of the thin film piezoelectric resonator element are provided. Face each other, fill the solder cavity with capillary penetration into the connection cavity, electrically connect the solder electrode and the back surface of the extraction electrode of the thin film piezoelectric resonator, and mount the thin film piezoelectric resonator on the mounting substrate A process.

  According to the present invention, it is possible to provide a thin film piezoelectric resonator element and a thin film piezoelectric resonator that have a new electrode connection structure, have excellent characteristics, and can be reduced in size and weight.

  Furthermore, according to the present invention, it is possible to provide a thin film piezoelectric resonator element and a method of manufacturing the thin film piezoelectric resonator that can eliminate the problems caused by the etching of the piezoelectric thin film.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
[Structure of thin-film piezoelectric resonator]
As shown in FIGS. 1 and 2, the thin film piezoelectric resonator element 1 according to the first embodiment of the present invention includes a substrate 2 and a first region A on the surface of the substrate 2 (the upper surface in FIG. 1). The first electrode 31 disposed on the substrate 2 and the second region B different from the first region A on the surface of the substrate 2 are electrically connected to the first electrode 31 at one end. The lead electrode 32 whose other end is electrically connected from the back surface of the substrate 2 (the lower surface in FIG. 1), and the piezoelectric thin film disposed on at least all of the first electrode 31 and the lead electrode 32 4, a second electrode 5 on the piezoelectric thin film 4, and a resonance cavity 21 disposed in the substrate 2 in a portion where the first electrode 31 is disposed. That is, the thin film piezoelectric resonance element 1 has a structure that vibrates a bridge in which the piezoelectric thin film 4 is sandwiched between the two first electrodes 31 and the second electrode 5.

  As the substrate 2, a Si substrate can be used practically. The resonance cavity 21 is disposed in the substrate 2 in the first region A, and is a planar rectangular opening penetrating from the surface of the substrate 2 to the back surface. Here, the “first region A” is used in the sense of a region in which a resonance action substantially occurs.

  In the first embodiment, Al or an Al alloy can be practically used for the first electrode 31. The extraction electrode 32 is integrally formed of the same conductive material as that of the first electrode 31. As shown in FIGS. 1 and 2, the extraction electrode 32 is extracted from the first electrode 31 disposed in the first region A in the central portion of the substrate 2 to the second region B on the right side. Here, the “second region B” means a region that is adjacent to the first region B and that includes a region that is connected to the first electrode 31 and is necessary for the arrangement of the extraction electrode 32. Used in

  As shown in FIG. 2, strip lines 33 and 34 for impedance matching are disposed on both sides of the substrate 2 with the first electrode 31 as the center. The strip lines 33 and 34 are formed of the same conductive material as that of the first electrode 31 in the same layer.

  In the portion where the extraction electrode 32 is provided, the substrate 2 is provided with a connection cavity 22 that exposes the back surface of the extraction electrode 32. The connection cavity 22 functions as a via hole for electrically connecting the back surface of the extraction electrode 32 and the mounting substrate (solder electrode shown in FIG. 10) on which the thin film piezoelectric resonator element 1 is mounted. The metallized layer 6 is disposed on the back surface of the extraction electrode 32 exposed in the connection cavity 22 and on the inner wall of the connection cavity 22. The metallized layer 6 has a function of promoting capillary penetration (pulling) into the connection cavity 22 of the solder electrode. For the metallized layer 6, a laminated film having an Au thin film on the surface of the Ni thin film can be used practically.

  In the first embodiment, AlN can be practically used for the piezoelectric thin film 4. By using the first electrode 31 having a two-layer structure having an amorphous crystal structure on the lower side, the orientation of AlN can be improved. By controlling the crystal orientation of AlN, the characteristics of the thin film piezoelectric resonator element 1 as a resonator can be improved. The piezoelectric thin film 4 is disposed so as to cover at least the first electrode 31 and the extraction electrode 32, and is not patterned on at least the first electrode 31 and the extraction electrode 32. In the first embodiment, the piezoelectric thin film 4 is disposed on the entire surface of the substrate 2. That is, the thin film piezoelectric resonance element 1 does not pattern the piezoelectric thin film 4 on the surface of the substrate 2, and the first electrode 31 sandwiched between the surface of the substrate 2 and the piezoelectric thin film 4 passes through the extraction electrode 32. A structure in which electrical connection is made on the back surface of the extraction electrode 32 is adopted. As a result, the flatness of the surface of the piezoelectric thin film 4 is improved, and the surface of the piezoelectric thin film 4 becomes substantially flat.

  Furthermore, in the first embodiment, AlN is formed by sputtering, and the crystal orientation of AlN is controlled to 1.5 ° or less in the X-ray rocking curve. Moreover, stress control is also performed for AlN, and the mechanical stress of AlN can be stabilized at the bridge portion.

  The thin film piezoelectric resonator element 1 according to the first embodiment is configured to operate in a frequency band of 2 GHz, for example, and an electromechanical coupling constant is 6.7% and a resonance Q value is 800. It was. Since the flatness of the surface of the piezoelectric thin film 4 is excellent, in the manufacturing process of the thin film piezoelectric resonator element 1, the in-plane distribution of the wafer is also excellent. For example, a plurality of thin film piezoelectric resonator elements manufactured on the entire surface of a 6-inch wafer. In Fig. 1, the characteristics relating to the electromechanical coupling constant and the resonance Q value could be obtained with good reproducibility. Further, since the piezoelectric thin film 4 is not etched in the manufacturing process of the thin film piezoelectric resonator element 1, the etched surface is not exposed to the atmosphere. In the thin film piezoelectric resonator 100 shown in FIG. 13 described above, the characteristics are stabilized due to the peculiarities such as the fact that the piezoelectric thin film 103 has an etching surface and the etching generates a step in the piezoelectric thin film 103. However, although a resonance Q value of about 600 was obtained, variation in the resonance Q value was large.

  For example, Mo can be practically used for the second electrode 5.

  The thin film piezoelectric resonance element 1 configured as described above has a new electrode connection structure in which the first electrode 31 is electrically connected from the back surface of the extraction electrode 32 through the extraction electrode 32, and the piezoelectric thin film 4 is patterned. It is possible to realize a reduction in size and weight that is excellent in characteristics due to the flattening of the surface without performing the annealing.

[Method for Manufacturing Thin Film Piezoelectric Resonator]
Next, a method for manufacturing the thin film piezoelectric resonance element 1 will be described. First, a substrate (for example, Si wafer) 2 having a thickness of, for example, 200 μm is prepared. Subsequently, although not shown, a silicon oxide film is formed on the surface of the substrate 2. The silicon oxide film is formed by a thermal oxidation method, for example, and is formed with a film thickness of about 1 μm.

  As shown in FIG. 3, an electrode layer 3 is formed on the entire surface of the substrate 2 with a silicon oxide film interposed. The electrode layer 3 is formed of a laminated film of, for example, a 20 nm thick TaAl thin film and a 200 nm thick Al thin film laminated on the TaAl thin film.

  As shown in FIG. 4, the electrode layer 3 is patterned using a photolithography technique, and the first electrode 31 and the extraction electrode 32 (and strip lines 33 and 34 not shown) are formed from the electrode layer 3. In the first embodiment, the first electrode 31 and the extraction electrode 32 are formed in the same process.

  The substrate 2 is loaded into a vacuum chamber of a high vacuum sputtering apparatus (not shown). Subsequently, as shown in FIG. 5, the piezoelectric thin film 4 covering at least the entire surface on the surface of the substrate 2, that is, the first electrode 31 and the extraction electrode 32 is formed. For example, AlN is used for the piezoelectric thin film 4 as described above, so that AlN is formed by sputtering. The piezoelectric thin film 4 is formed with a thickness of 1700 nm so as to conform to the frequency band of the W-CDMA system specification, for example. The frequency band can basically be determined by the types and film thicknesses of the first electrode 31 and the second electrode 5 and the film thickness of the piezoelectric thin film 4. Since each film thickness variation sensitively affects the frequency variation, each film thickness must be controlled with high accuracy.

  By forming an electrode layer on the piezoelectric thin film 4 and patterning the electrode layer using a photolithographic technique, the second electrode 5 is formed from the electrode layer as shown in FIG. The second electrode 5 is formed of Mo having a thickness of 200 nm, for example, and this Mo can be formed by sputtering.

  Next, the back surface processing of the substrate 2 is performed. Using a photolithography technique, a photoresist mask (not shown) having an opening on the back surface of the extraction electrode 32 is formed on the back surface of the substrate 2. Using this photoresist mask, the back surface of the substrate 2 is removed toward the front surface to form a connection cavity 22 that exposes the back surface of the extraction electrode 31 as shown in FIG. High speed RIE can be used practically for forming the connection cavity 22. After the connection cavity 22 is formed, the photoresist mask is removed.

  As shown in FIG. 8, a metallized layer is formed on the back surface of the extraction electrode 22 exposed from the connection cavity 22, on the inner wall of the connection cavity 22, and on a part of the back surface of the substrate 2.

  Again, using a photolithography technique, a photoresist mask (not shown) in which the first electrode 31 is opened is formed on the back surface of the substrate 2. Using this photoresist mask, the back surface of the substrate 2 is removed toward the front surface to form a resonance cavity 21 as shown in FIG. A Bosch etching system can be practically used for forming the resonance cavity 21. Since the degree of overlap between the first electrode 31 and the resonance cavity 21 sensitively affects the vibration characteristics, a Bosch etching system is employed so that the pattern conversion difference is minimized.

  In such a manufacturing method of the thin film piezoelectric resonator element 1, the process of patterning the thick piezoelectric thin film 4 by etching is eliminated and simplified, so that the manufacturing yield can be improved. In addition, since the residue generated in the etching process of the piezoelectric thin film 4 is eliminated, the maintenance process of the etching apparatus can be reduced, and the life of the etching apparatus can be further extended.

[Configuration of thin film piezoelectric resonator]
As shown in FIG. 10, the thin film piezoelectric resonator 10 according to the first embodiment further includes a mounting substrate 11 and a solder electrode 12 on the mounting substrate 11, and the surface of the mounting substrate 11 and the thin film The thin film piezoelectric resonator element 1 is mounted on the mounting substrate 11 with the back surface of the substrate 2 of the piezoelectric resonator element 1 facing each other, and electrically between the solder electrode 12 and the back surface of the extraction electrode 32 of the thin film piezoelectric resonator element 1. Connected. Further, in the thin film piezoelectric resonator 10, a mounting metallized portion 13 is disposed on the mounting substrate 11, and the bonding between the mounting metallized portion 13 and the second electrode 5 of the thin film piezoelectric resonator element 1 is performed. It is electrically connected through the wire 14. That is, the thin film piezoelectric resonator 10 is a mounting structure of the thin film piezoelectric resonator element 1.

  For example, a resin substrate can be used practically for the mounting substrate 11. In the first embodiment, the plane size of the connection cavity 22 of the thin film piezoelectric resonator element 1 is smaller than the plane size of the resonance cavity 21. For example, one side of the plane square of the connection cavity 22 is 50 μm. The dimensions are set. The connection cavity 22 is filled with a solder electrode 12, and the solder electrode 12 and the extraction electrode 32 of the thin film piezoelectric resonator element 1 are electrically and reliably connected through the metallized layer 6. For the solder electrode 12, for example, Pb-free solder can be used practically. The bonding wire 14 electrically connects the mounting metallized portion 13 and the second electrode 5 of the thin film piezoelectric resonator element 1 by, for example, a ball bonding method. For the bonding wire 14, for example, an Au wire, an Al wire, or the like can be used practically.

[Method for Manufacturing Thin Film Piezoelectric Resonator]
In the method of manufacturing the thin film piezoelectric resonator 10 shown in FIG. 10, first, each of the mounting metallized portion 13 and the solder electrode 12 is formed on the mounting substrate 11.

  Next, the surface of the mounting substrate 11 and the back surface of the substrate 2 of the thin film piezoelectric resonator element 1 face each other, the solder electrode 12 is filled into the connection cavity 22 by capillary penetration, and the solder electrode 12 and the thin film piezoelectric resonator element 1 are drawn out. The thin film piezoelectric resonance element 1 is mounted on the mounting substrate 11 while being electrically connected to the back surface of the electrode 32. Capillary penetration is a phenomenon in which molten solder is drawn into (crawled up) into the connection cavity 22 in the reflow process. The metallized layer 6 has good wettability with the solder electrode 12 and can promote the capillary penetration of the solder electrode 12.

  In the first embodiment, since one side of the plane square of the resonance cavity 21 of the thin film piezoelectric resonator element 1 is set to a size of 150 μm, the solder electrode 12 is slightly raised, but the back surface of the first electrode 31 Not reach. The solder electrode 12 is disposed over the entire mounting portion of the thin film piezoelectric resonator element 1, and the thin film piezoelectric resonator element 1 can be mounted on the mounting substrate 11 in a sealing structure close to hermetic sealing.

  In the thin film piezoelectric resonator 10 configured as described above, the thin film piezoelectric resonator element 1 can be reduced in size and weight, so that it can be reduced in size and weight. Furthermore, in the manufacturing method of the thin film piezoelectric resonator 10, the manufacturing yield can be improved.

(Second Embodiment)
The second embodiment of the present invention describes an example in which a flip chip mounting structure is applied to a thin film piezoelectric resonator. In the second embodiment and the third embodiment to be described later, the same components as those described in the first embodiment are denoted by the same reference numerals, and the description of the same components is not repeated. Since it overlaps, it abbreviate | omits.

  As shown in FIG. 11, the thin film piezoelectric resonator 10 according to the second embodiment includes a thin film piezoelectric element on the mounting substrate 11 such that the surface of the mounting substrate 11 faces the surface of the substrate 2 of the thin film piezoelectric resonator element 1. The resonant element 1 is mounted, and the bonding wire 14 is electrically connected to the back surface of the extraction electrode 32 of the thin film piezoelectric resonant element 1. One end of the bonding wire 14 is electrically connected directly to the back surface of the extraction electrode 32 through the connection cavity 22 of the thin film piezoelectric resonator element 1, and the other end is electrically connected to the mounting metallized portion 13.

  In the thin film piezoelectric resonator 1, the resonance cavity 21 disposed on the substrate 2 has a sharper cross-sectional shape (a shape in which an inner wall is formed perpendicular to the surface of the substrate 2) as a resonator characteristic. Is good. On the other hand, it is preferable to form the inner wall of the connecting cavity 22 in a tapered shape in terms of preventing interference with the bonding wire 14 and improving the ease of bonding.

  On the other hand, a mounting metallized portion 15 is disposed on the surface of the mounting substrate 11 corresponding to the second electrode 5, and the mounting metallized portion 15 and the second electrode 5 are electrically connected through a stud bump electrode 17. Connected mechanically and mechanically. For example, an Au stud bump electrode can be practically used for the stud bump electrode 17.

  Here, a dummy electrode 5D is disposed on the surface of the piezoelectric thin film 4 of the thin film piezoelectric resonator element 1 corresponding to the extraction electrode 32 or the connection cavity 22, and the surface of the mounting substrate 11 corresponding to the dummy electrode 5D. Is provided with a dummy metallized portion 15D, and a dummy stud bump electrode 17D is disposed between the dummy metallized portion 15D and the dummy electrode 5D. The dummy electrode 5D is formed by the same manufacturing process as the second electrode 5, the dummy metallized portion 15D is formed by the same manufacturing process as the mounting metallized portion 15 (or 13), and the dummy stud bump electrode 17D is the same as the stud bump electrode 17D. It is formed by the same manufacturing process. The dummy electrode 5D, the dummy metallized portion 15D, and the dummy stud bump electrode 17D adjust the height of the thin-film piezoelectric resonator element 1 and increase the mechanical strength just below the bonding region between the extraction electrode 32 and the bonding wire 14. Can be improved.

  In the thin film piezoelectric resonator element 1 and the thin film piezoelectric resonator 10 configured as described above, in addition to the effects obtained by the thin film piezoelectric resonator element 1 and the thin film piezoelectric resonator 10 according to the first embodiment described above, a thin film Since the step of forming the metallized layer 6 on the substrate 2 of the piezoelectric resonant element 1 can be eliminated, the number of manufacturing steps can be reduced.

(Third embodiment)
The third embodiment of the present invention describes a modification of the method for manufacturing the thin film piezoelectric resonator element 1. In the method of manufacturing the thin film piezoelectric resonator element 1 according to the first embodiment described above, the step of forming the resonance cavity 21 and the step of forming the connection cavity 22 in the substrate 2 are the same as shown in FIG. This is done according to the manufacturing process. This manufacturing method is suitable for the method of manufacturing the thin film piezoelectric resonator element 1 and the thin film piezoelectric resonator 10 according to the second embodiment described above, which does not require the step of forming the metallized layer 6.

  In the manufacturing method of the thin film piezoelectric resonator element 1 and the thin film piezoelectric resonator 10 as described above, in addition to the effects obtained by the manufacturing method of the thin film piezoelectric resonator element 1 and the thin film piezoelectric resonator 10 according to the first embodiment described above. Thus, the process of forming the resonance cavity 21 and the process of forming the connection cavity 22 can be performed by the same manufacturing process, so that the number of manufacturing processes can be reduced and the manufacturing yield can be improved. it can.

  The present invention is not limited to the embodiment described above. For example, the present invention relates to a thin film piezoelectric resonator element and a thin film piezoelectric resonator used in a frequency band of 800 MHz to 5 GHz in addition to the thin film piezoelectric resonator element 1 and the thin film piezoelectric resonator 10 used in a frequency band of 2 GHz. Can be applied.

  Furthermore, the present invention is not limited to the thin film piezoelectric resonator element 1 and the thin film piezoelectric resonator 10 that construct a filter, but can be applied to a thin film piezoelectric resonator element and a thin film piezoelectric resonator that construct a MEMS switch, a voltage control oscillator, and the like. it can.

1 is a configuration diagram of a thin film piezoelectric resonance element according to a first embodiment of the present invention. FIG. It is a top view of the thin film piezoelectric resonance element shown in FIG. It is a 1st process sectional view explaining a manufacturing method in a thin film piezoelectric resonance element concerning a 1st embodiment of the present invention. It is 2nd process sectional drawing. It is 3rd process sectional drawing. It is a 4th process sectional view. FIG. 10 is a fifth process cross-sectional view. It is 6th process sectional drawing. It is 7th process sectional drawing. It is a block diagram of the thin film piezoelectric resonator which mounted the thin film piezoelectric resonance element shown in FIG.1 and FIG.2. It is a block diagram of the thin film piezoelectric resonator which concerns on the 2nd Embodiment of this invention. It is process sectional drawing explaining the manufacturing method of the thin film piezoelectric resonance element which concerns on the 3rd Embodiment of this invention. It is sectional drawing of the thin film piezoelectric resonator which concerns on the prior art of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thin film piezoelectric resonance element 2 Board | substrate 21 Resonance cavity 22 Connection cavity 31 1st electrode 32 Lead electrode 4 Piezoelectric thin film 5 2nd electrode 5D Dummy electrode 6 Metallization layer 10 Thin film piezoelectric resonator 11 Mounting board 12 Solder electrode 13, 15 Mounting metallization part 15D Dummy metallization part 14 Bonding wire 17 Stud bump electrode 17D Dummy stud bump electrode

Claims (13)

A substrate,
A first electrode disposed in a first region on the substrate surface;
It is disposed in a second region different from the first region on the front surface of the substrate, and is formed so that one end is electrically connected to the first electrode and the other end is drawn from the back surface of the substrate. An extraction electrode;
A piezoelectric thin film disposed on the first electrode;
A second electrode on the piezoelectric thin film;
In a portion where the first electrode is disposed, a resonance cavity disposed in the substrate;
A thin film piezoelectric resonance element comprising:   2. The thin film piezoelectric resonance element according to claim 1, wherein the extraction electrode is integrally formed of the same conductive material as that of the first electrode.   The thin film piezoelectric resonator element according to claim 1, wherein the piezoelectric thin film is disposed on the entire surface of the substrate surface.   The thin film piezoelectric element according to any one of claims 1 to 3, wherein a connection cavity exposing the back surface of the extraction electrode is disposed on the substrate in a portion where the extraction electrode is disposed. Resonant element.   5. The thin film piezoelectric resonator according to claim 4, further comprising a metallization layer disposed on an inner wall of the connection cavity and a back surface of the lead electrode exposed from the connection cavity.   6. The thin film piezoelectric resonance element according to claim 5, wherein the metallized layer is disposed along an inner bottom surface and a side surface of the resonance cavity. In the thin film piezoelectric resonator element according to any one of claims 4 to 5,
A mounting board;
A solder electrode on the mounting substrate; and
The thin film piezoelectric resonator element is mounted on the mounting substrate so that the mounting substrate surface and the back surface of the thin film piezoelectric resonator element face each other, and the solder electrode and the lead electrode back surface of the thin film piezoelectric resonator element A thin film piezoelectric resonator characterized by electrically connecting the two. The thin film piezoelectric resonator element according to claim 4,
It further includes a mounting board,
The thin film piezoelectric resonator element is mounted on the mounting substrate with the mounting substrate surface facing the substrate surface of the thin film piezoelectric resonator element, and a wire is electrically connected to the back surface of the extraction electrode of the thin film piezoelectric resonator element. Thin film piezoelectric resonator, characterized in that it is connected electrically. A first electrode is formed in a first region on the substrate surface, and an extraction electrode connected to the first electrode is formed in a second region different from the first region on the substrate surface Process,
Forming a piezoelectric thin film on the first electrode;
Forming a second electrode on the piezoelectric thin film;
Forming a connection cavity in the substrate in the portion where the extraction electrode is formed;
Forming a resonance cavity in the substrate in the portion where the first electrode is formed;
A method of manufacturing a thin film piezoelectric resonance element comprising:   10. The thin film piezoelectric resonator according to claim 9, wherein the step of forming the piezoelectric thin film is a step of forming the piezoelectric thin film on the entire surface of the substrate, and the piezoelectric thin film is not patterned. Manufacturing method.   The step of forming the resonance cavity is the same as the step of forming a connection cavity in which the back surface of the extraction electrode is exposed at a portion of the substrate where the extraction electrode is formed. The manufacturing method of the thin film piezoelectric resonance element according to claim 10.   10. The step of forming the resonance cavity is a step different from the step of forming a connection cavity where the back surface of the extraction electrode is exposed at a portion of the substrate where the extraction electrode is formed. Or the manufacturing method of the thin film piezoelectric resonance element of Claim 10. In the manufacturing method of the thin film piezoelectric resonance element according to claim 11 or 12,
Forming a solder electrode on the mounting substrate;
The mounting substrate surface and the substrate back surface of the thin film piezoelectric resonator element face each other, the solder electrode is filled into the connection cavity by capillary penetration, and the solder electrode and the lead electrode back surface of the thin film piezoelectric resonator element are filled. And electrically mounting the thin film piezoelectric resonant element on the mounting substrate; and
A method of manufacturing a thin film piezoelectric resonator, further comprising:

Images