JP2009124697A - Resonance apparatus and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resonance apparatus for obtaining excellent resonance characteristics without causing insertion loss due to parasitic capacitance and to provide a manufacturing method thereof. <P>SOLUTION: The resonance apparatus is a BAW resonator including a support substrate 1 and a resonator 3 formed on one surface side of the support substrate 1. The resonator 3 comprises a columnar (cylindrical) core electrode 31 erected in the thickness direction of the support substrate 1 on one surface side of the support substrate 1, a piezoelectric material part 32 covering the outer peripheral surface of the core electrode 31, and an outer electrode 33 covering the outer peripheral surface of the piezoelectric material part 32. In this case, in the resonator 3, the outer peripheral shapes of the core electrode 31, the piezoelectric material part 32 and the outer electrode 33 respectively are circular on a cross section orthogonal to the thickness direction of the support substrate 1, and the core electrode 31, the piezoelectric material part 32 and the outer electrode 33 are concentrically formed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a resonance device and a manufacturing method thereof.

  Conventionally, as shown in FIG. 4, as a resonance device applicable to a high frequency filter used in a high frequency band of 1 GHz or more in the field of mobile communication devices such as a mobile phone, a support substrate 1 ′ and a support substrate 1 ′ are provided. A BAW (Bulk Acoustic Wave) resonator in which a resonator 130 ′ is formed on one surface side is proposed (see, for example, Patent Documents 1 and 2).

  Here, the resonator 130 ′ includes a lower electrode 131 ′ formed on the one surface side of the support substrate 1 ′ and a piezoelectric layer (piezoelectric layer) formed on the opposite side of the lower electrode 131 ′ from the support substrate 1 ′ side. Material portion) 132 ′ and an upper electrode 133 ′ formed on the opposite side of the piezoelectric layer 132 ′ from the lower electrode 131 ′ side, and the resonance frequency is inversely proportional to the film thickness of the piezoelectric layer 132 ′. The resonance frequency can be increased as the film thickness of the piezoelectric layer 132 ′ is reduced. As BAW resonators, SMR (Solidly Mounted Resonator) and FBAR (Film Bulk Acoustic Resonator) are known, and for example, application to a filter for UWB (Ultra Wide Band) is considered.

Incidentally, in the resonance device having the configuration shown in FIG. 4, the area of the resonance region 132a ′ in contact with the upper electrode 133 ′ of the piezoelectric layer 132 ′ is defined on the opposite side of the piezoelectric layer 132 ′ from the lower electrode 131 ′ side. An insulating film 4 ′ having an opening 4a ′ is formed to define the resonance region 132a ′. As the piezoelectric material of the piezoelectric layer 132 ′, AlN or ZnO is adopted in Patent Document 1 and PZT is adopted in Patent Document 2.
JP-T-2003-505905 (paragraphs [0043], [0045] and FIG. 8b) JP 2000-261281 (paragraphs [0029]-[0034] and FIG. 1)

  However, in the resonance apparatus having the configuration shown in FIG. 4, the upper electrode 133 ′ is formed across the resonance region 132a ′ of the piezoelectric layer 132 ′ and the insulating film 4 ′, and the insulating film 4 of the upper electrode 133 ′ is formed. A parasitic capacitance due to the insulating film 4 ′ between the surrounding electrode portion 133 b ′ formed above and the piezoelectric layer 132 ′ is generated, insertion loss due to the parasitic capacitance is generated, and the resonance characteristics are deteriorated. .

  The present invention has been made in view of the above reasons, and an object of the present invention is to provide a resonance device capable of obtaining good resonance characteristics without occurrence of insertion loss due to parasitic capacitance, and a method for manufacturing the same. is there.

  The invention of claim 1 is provided with a support substrate and a resonator formed on one surface side of the support substrate, and the resonator is a columnar shape erected in the thickness direction of the support substrate on the one surface side of the support substrate. The core electrode, a piezoelectric material portion covering the outer peripheral surface of the core electrode, and an outer electrode covering the outer peripheral surface of the piezoelectric material portion.

  According to the present invention, the resonator includes a columnar core electrode erected in the thickness direction of the support substrate on one surface side of the support substrate, the piezoelectric material portion covering the outer peripheral surface of the core electrode, and the piezoelectric material portion. Since it is composed of an outer electrode that covers the outer peripheral surface, only the piezoelectric material part is interposed between the core electrode and the outer electrode, and there is no insertion loss due to parasitic capacitance, resulting in good resonance. It becomes possible to obtain characteristics.

  According to a second aspect of the present invention, in the first aspect of the invention, the resonator is formed such that the core electrode, the piezoelectric material portion, and the outer electrode are concentrically formed in a cross section orthogonal to the thickness direction of the support substrate. It is characterized by being.

  According to this invention, the thickness of the piezoelectric material portion interposed between the core electrode and the outer electrode is made uniform, and it becomes possible to obtain good resonance characteristics without causing resonance mode disturbance. . Further, according to the present invention, the resonator has an outer peripheral shape since the outer peripheral shape of each of the core electrode, the piezoelectric material portion, and the outer electrode is circular in a cross section orthogonal to the thickness direction of the support substrate. Since there are no corners, the resonance mode is not disturbed due to the corners, and good resonance characteristics can be obtained.

  A third aspect of the invention is characterized in that, in the first or second aspect of the invention, the piezoelectric material of the piezoelectric material portion is KNN.

  According to this invention, the electromechanical coupling coefficient can be increased as compared with the case where the piezoelectric material of the piezoelectric material portion is AlN, and the lead-type piezoelectric material such as PZT has a larger electromechanical coupling coefficient than AlN. Compared to the environmental load.

  A fourth aspect of the present invention is the method of manufacturing a resonance device according to any one of the first to third aspects, wherein the piezoelectric material layer serving as a basis of the piezoelectric material portion is formed on the entire surface of the one surface side of the support substrate. A piezoelectric material layer forming step for forming the first electrode, a first patterning step for patterning the piezoelectric material layer to form a columnar piezoelectric material portion comprising a part of the piezoelectric material layer, and a support after the first patterning step. An electrode material layer forming step for forming an electrode material layer serving as a basis for both the core electrode and the outer electrode on the entire surface of the one surface side of the substrate; and after the electrode material layer forming step, the surface of the electrode material layer is a piezoelectric material A flattening step of flattening so as to be flush with the end surface of the portion, and a core electrode and an outer electrode each comprising a part of the electrode material layer are formed by patterning the electrode material layer after the flattening step. 2 paternine Characterized in that it comprises a step.

  According to this invention, the piezoelectric material layer that forms the basis of the piezoelectric material portion is formed on the entire surface of the one surface side of the support substrate, and then the piezoelectric material layer is patterned to form the columnar piezoelectric material that is part of the piezoelectric material layer. Since the material portion is formed, the piezoelectric material portion having good crystallinity can be formed with high dimensional accuracy. After forming the piezoelectric material portion, both the core electrode and the outer electrode are formed on the entire surface of the one surface side of the support substrate. After forming the electrode material layer that is the basis of the electrode material layer, the surface of the electrode material layer is flattened so as to be flush with the end face of the piezoelectric material portion, and then the electrode material layer is patterned to form one of the electrode material layers. Since the core electrode and the outer electrode formed of the portion are formed, the core electrode and the outer electrode can be simultaneously formed with a positional accuracy and a dimensional accuracy with respect to the piezoelectric material portion. A resonator comprising a columnar core electrode erected in the thickness direction of the support substrate, a piezoelectric material portion covering the outer peripheral surface of the core electrode, and an outer electrode covering the outer peripheral surface of the piezoelectric material portion. Since it can be formed easily and in large quantities, it is possible to provide a low-cost resonant device capable of obtaining good resonance characteristics without causing insertion loss due to parasitic capacitance.

  According to the first aspect of the present invention, insertion loss due to parasitic capacitance does not occur, and it is possible to obtain good resonance characteristics.

  According to the invention of claim 4, there is an effect that it is possible to provide a low-cost resonance device capable of obtaining good resonance characteristics without causing insertion loss due to parasitic capacitance.

  As shown in FIG. 1, the resonance device of the present embodiment is a BAW resonator including a support substrate 1 and a resonator 3 formed on one surface side of the support substrate 1. A columnar (in this embodiment, columnar) core electrode 31 erected in the thickness direction of the support substrate 1 on the one surface side of the substrate 1, a piezoelectric material portion 32 covering the outer peripheral surface of the core electrode 31, An outer electrode 33 that covers the outer peripheral surface of the piezoelectric material portion 32 is formed. In the present embodiment, the core electrode 31 and the outer electrode 33 constitute a pair of electrodes sandwiching the piezoelectric material portion 32.

Here, in the resonance device of the present embodiment, PZT, which is a kind of lead-based piezoelectric material, is adopted as the piezoelectric material of the piezoelectric material portion 32, and an insulating film made of a silicon oxide film is used as the support substrate 1 on the one surface side. The support substrate 1 is not limited to such a silicon substrate, but may be an MgO substrate, an STO (SrTiO ₃ ) substrate, or the like. Here, in the present embodiment, PZT is adopted as the piezoelectric material of the piezoelectric material portion 32. However, not only PZT but also other lead-based piezoelectric materials depending on the resonance characteristics required for the resonator 3 and the like. (For example, PZT-PMT or PZT to which an appropriate impurity is added), AlN, ZnO, or the like may be employed. Further, lead-free KNN (potassium sodium diobate) may be adopted as the piezoelectric material of the piezoelectric material portion 32. If KNN is adopted, the electromechanical coupling coefficient is larger than that in the case where the piezoelectric material is AlN. In addition, the environmental load can be reduced as compared with the case of using a lead-based piezoelectric material. The composition of KNN is represented by the chemical formula K _x Na _1-x NbO ₃ , and for example, x = 0.5 may be used, but this value is an example and is not particularly limited. For KNN, for example, impurities such as Li, Nb, Ta, Sb, and Cu may be added.

  The resonator 3 employs Pt as the material of the core electrode 31 and the outer electrode 33, but is not limited to Pt, and may employ, for example, Al, Mo, W, Ir, Cr, Ru, or the like. .

  In the resonance device of the present embodiment, the resonator 3 includes a columnar core electrode 31 erected in the thickness direction of the support substrate 1 on the one surface side of the support substrate 1 and a piezoelectric film that covers the outer peripheral surface of the core electrode 31. Since the material portion 32 and the outer electrode 33 covering the outer peripheral surface of the piezoelectric material portion 32 are included, only the piezoelectric material portion 32 is interposed between the core electrode 31 and the outer electrode 33, and parasitic Insertion loss due to capacitance does not occur, and good resonance characteristics can be obtained.

  Incidentally, in the resonator 3, the core electrode 31, the piezoelectric material portion 32, and the outer electrode 33 are formed concentrically in a cross section orthogonal to the thickness direction of the support substrate 1. The thickness of the piezoelectric material portion 32 interposed therebetween is made uniform, and it is possible to obtain good resonance characteristics without causing disturbance of the resonance mode.

  Here, in the resonator 3, in the cross section orthogonal to the thickness direction of the support substrate 1, the outer peripheral shape of each of the core electrode 31, the piezoelectric material portion 32, and the outer electrode 33 is circular, and the outer peripheral shape has corners. Since it does not exist, the resonance mode is not disturbed due to the corners, and good resonance characteristics can be obtained. In the present embodiment, the core electrode 31 and the outer electrode 33 are arranged so as to sandwich the piezoelectric material portion 32 in the radial direction of the core electrode 31. In the resonance device of the present embodiment, the resonance frequency of the resonator 3 is set to 4 GHz, and the thickness of the piezoelectric material portion 32 in the radial direction of the core electrode 31 is set to 300 nm. This is an example and is not particularly limited. In addition, when the resonance frequency is designed in the range of 3 GHz to 5 GHz, the thickness of the piezoelectric material portion 32 may be appropriately set in the range of 200 nm to 600 nm.

  Hereinafter, the manufacturing method of the resonance device of the present embodiment will be described with reference to FIG.

  First, by performing a piezoelectric material layer forming process in which a piezoelectric material layer 32a serving as a basis of the piezoelectric material portion 32 is formed on the entire surface of the support substrate 1 by the sputtering method, the CVD method, the sol-gel method, or the like. The structure shown in 2 (a) is obtained.

  Thereafter, by performing a first patterning process for forming a columnar piezoelectric material portion 32 made of a part of the piezoelectric material layer 32a by patterning the piezoelectric material layer 32a using a photolithography technique and an etching technique, FIG. The structure shown in 2 (b) is obtained.

  Next, an electrode material layer formation in which an electrode material layer 30 serving as a basis for both the core electrode 31 and the outer electrode 33 is formed on the entire surface of the support substrate 1 by the sputtering method, the vapor deposition method, the CVD method, or the like. By performing the process, the structure shown in FIG. Here, the thickness of the electrode material layer 30 is set to be thicker than the thickness of the piezoelectric material layer 32a described above.

  After the above-described electrode material layer forming step, the structure shown in FIG. 2D is obtained by performing a flattening step of flattening the surface of the electrode material layer 30 so as to be flush with the end face of the piezoelectric material portion 32. obtain. Here, in the planarization step, the surface of the electrode material layer 30 may be planarized so as to be flush with the end surface of the piezoelectric material portion 32 by, for example, an etch back method or a CMP method.

  Thereafter, by performing a second patterning step of forming the core electrode 31 and the outer electrode 33, which are part of the electrode material layer 30, by patterning the electrode material layer 30 using photolithography technology and etching technology, respectively. Thus, the resonator 3 having the structure shown in FIG.

  According to the above-described method for manufacturing a resonance device, the piezoelectric material layer 32a serving as the basis of the piezoelectric material portion 32 is formed on the entire surface of the support substrate 1 on the one surface side, and then the piezoelectric material layer 32a is patterned to form the piezoelectric material. Since the columnar piezoelectric material portion 32 formed of a part of the material layer 32a is formed, the piezoelectric material portion 32 having good crystallinity can be formed with high dimensional accuracy. After the piezoelectric material portion 32 is formed, the support substrate 1 After the electrode material layer 30 serving as the basis of both the core electrode 31 and the outer electrode 33 is formed on the entire surface on the one surface side, the surface of the electrode material layer 30 is flush with the end face of the piezoelectric material portion 32. And then patterning the electrode material layer 30 to form the core electrode 31 and the outer electrode 33 respectively consisting of a part of the electrode material layer 30, so that the core electrode 31 and the outer electrode 33 are The columnar core electrode can be simultaneously formed with good positional accuracy and dimensional accuracy with respect to the electric material portion 32, and as a result, is provided on the one surface side of the support substrate 1 in the thickness direction of the support substrate 1. The resonator 3 including the piezoelectric material portion 32 covering the outer peripheral surface of the core electrode 31 and the outer electrode 33 covering the outer peripheral surface of the piezoelectric material portion 32 can be formed easily and in large quantities. Therefore, it is possible to provide a low-cost resonance device that can obtain good resonance characteristics without causing insertion loss due to parasitic capacitance. According to the manufacturing method described above, the resonator 3 can be formed by using a semiconductor manufacturing process. Therefore, the resonator 3 can be easily formed in a large amount, and as shown in FIG. The child 3 can also be integrated.

  By the way, when the above-described resonance device is applied as a filter having a sharp cutoff characteristic and a wide bandwidth in a high frequency band of 3 GHz or more, for example, a filter for UWB (Ultra Wide Band), a plurality of resonators 3 are used. Is formed on the one surface side of the support substrate 1 and the plurality of resonators 3 are connected so as to constitute a ladder type filter, the cost and size of the UWB filter can be reduced.

The resonance apparatus of embodiment is shown, (a) is the schematic perspective view which fractured | ruptured partially, (b) is A-A 'schematic sectional drawing of (a). It is principal process sectional drawing for demonstrating the manufacturing method same as the above. It is a schematic plan view which shows the other structural example same as the above. It is a schematic sectional drawing of the resonance apparatus which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Support substrate 3 Resonator 30 Electrode material layer 31 Core electrode 32 Piezoelectric material part 32a Piezoelectric material layer 33 Outer electrode

Claims (4)

  A support substrate; and a resonator formed on one surface side of the support substrate. The resonator includes a columnar core electrode erected in the thickness direction of the support substrate on the one surface side of the support substrate, and a core electrode. A resonance device comprising: a piezoelectric material portion covering an outer peripheral surface of the piezoelectric material portion; and an outer electrode covering the outer peripheral surface of the piezoelectric material portion.   The resonator according to claim 1, wherein the resonator is formed such that the core electrode, the piezoelectric material portion, and the outer electrode are concentrically formed in a cross section orthogonal to a thickness direction of the support substrate.   3. The resonance device according to claim 1, wherein the piezoelectric material of the piezoelectric material portion is KNN.   4. The method for manufacturing a resonance device according to claim 1, wherein a piezoelectric material layer is formed to form a piezoelectric material layer serving as a basis of a piezoelectric material portion on the entire surface of one surface side of the support substrate. A first patterning step of forming a columnar piezoelectric material portion comprising a part of the piezoelectric material layer by patterning the piezoelectric material layer, and the one surface side of the support substrate after the first patterning step An electrode material layer forming step for forming an electrode material layer serving as a basis for both the core electrode and the outer electrode on the entire surface, and after the electrode material layer forming step, the surface of the electrode material layer is flush with the end face of the piezoelectric material portion. And a second patterning step of forming a core electrode and an outer electrode each of which is a part of the electrode material layer by patterning the electrode material layer after the planarization step. This Method of manufacturing a resonator device according to claim.

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