JP2007306210A - Piezoelectric thin film device - Google Patents

Piezoelectric thin film device Download PDF

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JP2007306210A
JP2007306210A JP2006131445A JP2006131445A JP2007306210A JP 2007306210 A JP2007306210 A JP 2007306210A JP 2006131445 A JP2006131445 A JP 2006131445A JP 2006131445 A JP2006131445 A JP 2006131445A JP 2007306210 A JP2007306210 A JP 2007306210A
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thin film
piezoelectric thin
surface electrode
electrode
piezoelectric
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JP4811931B2 (en
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Yukihisa Osugi
幸久 大杉
Shosaku Goji
庄作 郷治
Kengo Suzuki
健吾 鈴木
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NGK Insulators Ltd
NGK Optoceramics Co Ltd
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NGK Optoceramics Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To prevent characteristic deterioration due to interference among a plurality of resonators in a piezoelectric thin film device including the plurality of resonators. <P>SOLUTION: A piezoelectric thin film filter 1 has such a structure that an adhesion layer 12, a cavity forming film 13, a reverse-surface electrode 15, a piezoelectric thin film 16, and a top-surface electrode 17 are laminated in this order on a support material 11. A top-surface electrode 171 faces a lower surface electrode 151 across a piezoelectric thin film 26 in an opposition region E11 to constitute a resonator (series resonator) R11 including the top-surface electrode 171 and lower surface electrode 151 as driving electrodes. A top-surface electrode 172 faces a reverse-surface electrode 152 across the piezoelectric thin film 26 in an opposition region E12 to constitute a resonator (parallel resonator) R12 including the top-surface electrode 172 and reverse-surface electrode 172 as driving electrodes. A reverse-surface electrode 153 is a wiring electrode connecting the lower surface electrode 151 and reverse-surface electrode 152, and different in material and film thickness from the lower surface electrodes 151 and 152. The resonators R11 and R12 are acoustically separated from each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、複数の共振器を含む圧電薄膜デバイスに関する。   The present invention relates to a piezoelectric thin film device including a plurality of resonators.

図８は、従来の圧電薄膜フィルタ９の主要な構成を模式的に示す図である。図８は、圧電薄膜フィルタ９を斜方から見た斜視図となっている。圧電薄膜フィルタ９は、２個の共振器を組み合わせたラダー型のフィルタとなっている。   FIG. 8 is a diagram schematically showing the main configuration of a conventional piezoelectric thin film filter 9. FIG. 8 is a perspective view of the piezoelectric thin film filter 9 viewed from an oblique direction. The piezoelectric thin film filter 9 is a ladder type filter in which two resonators are combined.

図８に示すように、圧電薄膜フィルタ９は、圧電体薄膜９１と、対向領域Ｅ９１において圧電体薄膜９１を挟んで対向し、第１の共振器を形成する駆動電極９２１及び９３１と、対向領域Ｅ９２において圧電体薄膜９１を挟んで対向し、第２の共振器を形成する駆動電極９２２及び９３２とを備える。圧電薄膜フィルタ９では、圧電体薄膜９１の下面に形成された駆動電極９３１と９３２とは、配線電極９３３によって接続される。   As shown in FIG. 8, the piezoelectric thin film filter 9 is opposed to the piezoelectric thin film 91 across the piezoelectric thin film 91 in the opposed region E91, and the drive electrodes 921 and 931 that form the first resonator, and the opposed region E92 includes drive electrodes 922 and 932 that are opposed to each other with the piezoelectric thin film 91 interposed therebetween and form a second resonator. In the piezoelectric thin film filter 9, the drive electrodes 931 and 932 formed on the lower surface of the piezoelectric thin film 91 are connected by the wiring electrode 933.

なお、特許文献１は、本願発明と関連する先行技術文献であり、圧電薄膜フィルタに含まれる複数の共振器を接続する配線を積層構造とする技術を開示している。   Patent Document 1 is a prior art document related to the present invention, and discloses a technique in which wirings connecting a plurality of resonators included in a piezoelectric thin film filter have a laminated structure.

特開２００４−１０４４４９号公報JP 2004-104449 A

しかし、従来の圧電薄膜フィルタ９では、第１の共振器において励振された弾性波が第２の共振器まで到達し、第２の共振器の共振に起因する副共振が第１の共振器の主共振に重畳する場合がある。逆に、第２の共振器において励振された弾性波が第１の共振器まで到達し、第１の共振器の共振に起因する副共振が第２の共振器の主共振に重畳する場合がある。このような第１の共振器と第２の共振器との干渉は、圧電薄膜フィルタ９の濾波特性に影響を与え、望ましくないリップルの原因となることがある。   However, in the conventional piezoelectric thin film filter 9, the elastic wave excited in the first resonator reaches the second resonator, and the sub-resonance caused by the resonance of the second resonator is the first resonator. It may be superimposed on the main resonance. Conversely, the elastic wave excited in the second resonator may reach the first resonator, and the sub-resonance resulting from the resonance of the first resonator may be superimposed on the main resonance of the second resonator. is there. Such interference between the first resonator and the second resonator affects the filtering characteristics of the piezoelectric thin film filter 9 and may cause undesirable ripples.

本発明は、この問題を解決するためになされたもので、圧電薄膜フィルタ９に代表される、複数の共振器を含む圧電薄膜デバイスにおいて、複数の共振器の干渉に起因する特性劣化を防ぐことを目的とする。   The present invention has been made to solve this problem, and in a piezoelectric thin film device including a plurality of resonators represented by a piezoelectric thin film filter 9, characteristic deterioration caused by interference of the plurality of resonators is prevented. With the goal.

請求項１の発明は、圧電体薄膜と、第１対向領域において前記圧電体薄膜を挟んで対向するように前記圧電体薄膜の第１主面及び第２主面にそれぞれ形成され、第１共振器を構成する第１駆動電極及び第２駆動電極と、第２対向領域において前記圧電体薄膜を挟んで対向するように前記圧電体薄膜の第１主面及び第２主面にそれぞれ形成され、第２共振器を構成する第３駆動電極及び第４駆動電極と、前記第１主面に形成され、前記第１駆動電極と前記第３駆動電極とを接続する配線電極と、を備え、前記第１駆動電極と前記配線電極との境界及び前記第３駆動電極と前記配線電極との境界の両側で電極の材質が異なる圧電薄膜デバイスである。   According to a first aspect of the present invention, the piezoelectric thin film is formed on each of the first main surface and the second main surface of the piezoelectric thin film so as to oppose the piezoelectric thin film in the first opposing region, and the first resonance Formed on the first main surface and the second main surface of the piezoelectric thin film so as to oppose the first driving electrode and the second driving electrode constituting the container, with the piezoelectric thin film interposed therebetween in the second opposing region, A third drive electrode and a fourth drive electrode constituting a second resonator, and a wiring electrode formed on the first main surface and connecting the first drive electrode and the third drive electrode, In the piezoelectric thin film device, the material of the electrode is different on the boundary between the first drive electrode and the wiring electrode and on both sides of the boundary between the third drive electrode and the wiring electrode.

請求項２の発明は、前記配線電極の膜厚が前記第１駆動電極及び前記第３駆動電極の膜厚より厚い請求項１に記載の圧電薄膜デバイスである。   A second aspect of the present invention is the piezoelectric thin film device according to the first aspect, wherein the thickness of the wiring electrode is larger than the thickness of the first drive electrode and the third drive electrode.

請求項３の発明は、前記配線電極が金膜を含む請求項１又は請求項２に記載の圧電薄膜デバイスである。   A third aspect of the present invention is the piezoelectric thin film device according to the first or second aspect, wherein the wiring electrode includes a gold film.

請求項４の発明は、前記第１対向領域の内部の任意の点と前記第２対向領域の内部の任意の点とを結ぶ直線が前記配線電極を横断する請求項１ないし請求項３のいずれかに記載の圧電薄膜デバイスである。   According to a fourth aspect of the present invention, in any one of the first to third aspects, a straight line connecting an arbitrary point inside the first opposing region and an arbitrary point inside the second opposing region crosses the wiring electrode. The piezoelectric thin film device according to claim 1.

請求項１ないし請求項４の発明によれば、複数の共振器を音響的に分離することができるので、複数の共振器の干渉に起因する圧電薄膜デバイスの特性劣化を防ぐことができる。   According to the first to fourth aspects of the present invention, since the plurality of resonators can be acoustically separated, the deterioration of the characteristics of the piezoelectric thin film device due to the interference of the plurality of resonators can be prevented.

請求項２又は請求項３の発明によれば、配線電極で弾性波を減衰させることができるので、複数の共振器をより確実に音響的に分離することができる。   According to the invention of claim 2 or claim 3, since the elastic wave can be attenuated by the wiring electrode, a plurality of resonators can be acoustically separated more reliably.

請求項４の発明によれば、複数の共振器をより確実に音響的に分離することができる。   According to the invention of claim 4, a plurality of resonators can be acoustically separated more reliably.

以下では、２個の共振器を組み合わせたラダー型のフィルタ（以下、「圧電薄膜フィルタ」）を例として、本発明の圧電薄膜デバイスの望ましい実施形態について説明する。しかし、以下の実施形態は、本発明の圧電薄膜デバイスが圧電薄膜フィルタのみに限定されることを意味するものではない。すなわち、本発明における圧電薄膜デバイスとは、一般的に言えば、複数の共振器を含む圧電薄膜デバイス全般を意味しており、複数の共振器を含むフィルタ、デュプレクサ、トリプレクサ及びトラップ等を包含している。また、圧電薄膜デバイスに含まれる共振器の数が２個であることも必須ではなく、圧電薄膜デバイスが３個以上の共振器を含む場合にも本発明は適用可能である。   Hereinafter, a preferred embodiment of the piezoelectric thin film device of the present invention will be described by taking a ladder type filter (hereinafter referred to as “piezoelectric thin film filter”) in which two resonators are combined as an example. However, the following embodiments do not mean that the piezoelectric thin film device of the present invention is limited only to the piezoelectric thin film filter. That is, in general, the piezoelectric thin film device in the present invention means a general piezoelectric thin film device including a plurality of resonators, and includes a filter, a duplexer, a triplexer, a trap and the like including a plurality of resonators. ing. Further, it is not essential that the number of resonators included in the piezoelectric thin film device is two, and the present invention can be applied to a case where the piezoelectric thin film device includes three or more resonators.

＜１ 圧電薄膜フィルタの構成＞
＜１．１ 全体構成＞
図１〜図４は、本発明の望ましい実施形態に係る圧電薄膜フィルタ１の構成を示す模式図である。図１は、圧電薄膜フィルタ１を斜方から見た斜視図、図２は、圧電薄膜フィルタ１を上方から見た平面図、図３は、図１のIII-IIIの切断線における圧電薄膜フィルタ１の断面を示す断面図、図４は、圧電薄膜フィルタ１に含まれる２個の共振器Ｒ１１及びＲ１２の電気的な接続を示す回路図となっている。なお、図１には、説明の便宜上、左右方向をＸ軸方向、前後方向をＹ軸方向、上下方向をＺ軸方向とするＸＹＺ直交座標系が定義されている。 <1 Piezoelectric thin film filter configuration>
<1.1 Overall configuration>
1 to 4 are schematic views showing the configuration of a piezoelectric thin film filter 1 according to a preferred embodiment of the present invention. FIG. 1 is a perspective view of the piezoelectric thin film filter 1 seen from an oblique direction, FIG. 2 is a plan view of the piezoelectric thin film filter 1 seen from above, and FIG. 3 is a piezoelectric thin film filter taken along the section line III-III in FIG. FIG. 4 is a circuit diagram showing an electrical connection between two resonators R11 and R12 included in the piezoelectric thin film filter 1. FIG. For convenience of explanation, FIG. 1 defines an XYZ orthogonal coordinate system in which the left-right direction is the X-axis direction, the front-rear direction is the Y-axis direction, and the up-down direction is the Z-axis direction.

図１〜図４に示すように、圧電薄膜フィルタ１は、支持基板１１の上に、接着層１２、キャビティ形成膜１３、下面電極１５（１５１〜１５３）、圧電体薄膜１６及び上面電極１７（１７１〜１７３）をこの順序で積層した構造を有している。   As shown in FIGS. 1 to 4, the piezoelectric thin film filter 1 has an adhesive layer 12, a cavity forming film 13, a lower surface electrode 15 (151 to 153), a piezoelectric thin film 16 and an upper surface electrode 17 (on a support substrate 11. 171 to 173) are stacked in this order.

＜１．２ 圧電体薄膜＞
圧電体薄膜１６は、圧電体基板を除去加工することにより得られる。より具体的には、圧電体薄膜１６は、単独で自重に耐え得る厚み（例えば、５０μｍ以上）を有する圧電体基板を、単独で自重に耐え得ない膜厚（例えば、１０μｍ以下）まで除去加工で薄肉化することにより得られる。 <1.2 Piezoelectric thin film>
The piezoelectric thin film 16 is obtained by removing the piezoelectric substrate. More specifically, the piezoelectric thin film 16 removes a piezoelectric substrate having a thickness that can withstand its own weight (for example, 50 μm or more) to a thickness (for example, 10 μm or less) that cannot withstand its own weight. It can be obtained by thinning.

圧電体薄膜１６を構成する圧電材料としては、所望の圧電特性を有する圧電材料を選択することができるが、水晶（SiO2）、ニオブ酸リチウム(LiNbO3）、タンタル酸リチウム（LiTaO3）、四ホウ酸リチウム（Li2B4O7）、酸化亜鉛（ZnO）、ニオブ酸カリウム（KNbO3）及びランガサイト（La3Ga3SiO14）等の粒界を含まない単結晶材料を選択することが望ましい。圧電体薄膜１６を構成する圧電材料として単結晶材料を用いることにより、圧電体薄膜１６の電気機械結合係数及び機械的品質係数を向上することができるからである。 As the piezoelectric material constituting the piezoelectric thin film 16, can be selected piezoelectric material having a desired piezoelectric properties, quartz (SiO 2), lithium niobate (LiNbO 3), lithium tantalate (LiTaO 3), Select single crystal materials that do not contain grain boundaries such as lithium tetraborate (Li 2 B 4 O 7 ), zinc oxide (ZnO), potassium niobate (KNbO 3 ) and langasite (La 3 Ga 3 SiO 14 ) It is desirable. This is because by using a single crystal material as the piezoelectric material constituting the piezoelectric thin film 16, the electromechanical coupling coefficient and the mechanical quality factor of the piezoelectric thin film 16 can be improved.

また、圧電体薄膜１６における結晶方位も、所望の圧電特性を有する結晶方位を選択することができる。ここで、圧電体薄膜１６における結晶方位は、共振器Ｒ１１及びＲ１２の共振周波数や***振周波数の温度特性が良好となる結晶方位とすることが望ましく、周波数温度係数が「０」となる結晶方位とすることがさらに望ましい。   In addition, as the crystal orientation in the piezoelectric thin film 16, a crystal orientation having desired piezoelectric characteristics can be selected. Here, the crystal orientation in the piezoelectric thin film 16 is preferably a crystal orientation in which the temperature characteristics of the resonance frequency and antiresonance frequency of the resonators R11 and R12 are favorable, and the crystal orientation in which the frequency temperature coefficient is “0”. Is more desirable.

圧電体基板の除去加工は、切削、研削及び研磨等の機械加工並びにエッチング等の化学加工等により行う。ここで、複数の除去加工方法を組み合わせ、加工速度が速い除去加工方法から、加工対象に生じる加工変質が小さい除去加工方法へと除去加工方法を段階的に切り替えながら圧電体基板を除去加工すれば、高い生産性を維持しつつ、圧電体薄膜１６の品質を向上し、圧電薄膜フィルタ１の特性を向上することができる。例えば、圧電体基板を固定砥粒に接触させて削る研削及び圧電体基板を遊離砥粒に接触させて削る研磨を順次行った後に、当該研磨によって圧電体基板に生じた加工変質層を仕上げ研磨により除去するようにすれば、圧電体基板を削る速度が早くなり、圧電薄膜フィルタ１の生産性を向上することができるとともに、圧電体薄膜１６の品質を向上することにより、圧電薄膜フィルタ１の特性を向上することができる。なお、圧電体基板の除去加工のより具体的な方法については、後述する実施例において説明する。   The removal processing of the piezoelectric substrate is performed by mechanical processing such as cutting, grinding and polishing, and chemical processing such as etching. Here, if a plurality of removal processing methods are combined and the piezoelectric substrate is removed while switching the removal processing method step by step from the removal processing method with a high processing speed to the removal processing method with a small process alteration occurring on the processing target. The quality of the piezoelectric thin film 16 can be improved and the characteristics of the piezoelectric thin film filter 1 can be improved while maintaining high productivity. For example, after performing grinding in which a piezoelectric substrate is brought into contact with fixed abrasive grains and polishing in which a piezoelectric substrate is brought into contact with loose abrasive grains in order, a work-affected layer generated on the piezoelectric substrate by the polishing is finished and polished. If it removes by this, the speed at which the piezoelectric substrate is cut can be increased, the productivity of the piezoelectric thin film filter 1 can be improved, and the quality of the piezoelectric thin film 16 can be improved. The characteristics can be improved. Note that a more specific method of removing the piezoelectric substrate will be described in an embodiment described later.

このような圧電薄膜フィルタ１では、圧電体薄膜１６をスパッタリング等により成膜した場合と異なり、圧電体薄膜１６を構成する圧電材料や圧電体薄膜１６における結晶方位が下地の制約を受けないので、圧電体薄膜１６を構成する圧電材料や圧電体薄膜１６における結晶方位の選択の自由度が高くなっている。したがって、圧電薄膜フィルタ１では、所望の特性を実現することが容易になっている。   In such a piezoelectric thin film filter 1, unlike the case where the piezoelectric thin film 16 is formed by sputtering or the like, the piezoelectric material constituting the piezoelectric thin film 16 and the crystal orientation in the piezoelectric thin film 16 are not subject to the restrictions of the base. The degree of freedom in selecting the crystal orientation of the piezoelectric material constituting the piezoelectric thin film 16 and the piezoelectric thin film 16 is high. Therefore, the piezoelectric thin film filter 1 can easily achieve desired characteristics.

この圧電体薄膜１６には、圧電体薄膜１６の上面と下面との間を貫通し、対向領域Ｅ１１及びＥ１２以外の領域において圧電体薄膜１６を挟んで対向する上面電極１７３と下面電極１５３とを導通させるバイアホールＶＨ１が形成されている。バイアホールＶＨ１は、その内側面に成膜された導電体薄膜により上面電極１７３と下面電極１５３とを短絡している。   The piezoelectric thin film 16 includes an upper surface electrode 173 and a lower surface electrode 153 that penetrate between the upper surface and the lower surface of the piezoelectric thin film 16 and are opposed to each other with the piezoelectric thin film 16 interposed therebetween in a region other than the opposed regions E11 and E12. A via hole VH1 to be conducted is formed. The via hole VH1 short-circuits the upper surface electrode 173 and the lower surface electrode 153 with a conductive thin film formed on the inner surface thereof.

＜１．３ 上面電極及び下面電極＞
上面電極１７及び下面電極１５は、それぞれ、圧電体薄膜１６の上面及び下面に導電材料を成膜することにより形成された導電体薄膜である。 <1.3 Upper surface electrode and lower surface electrode>
The upper surface electrode 17 and the lower surface electrode 15 are conductor thin films formed by depositing a conductive material on the upper surface and the lower surface of the piezoelectric thin film 16, respectively.

上面電極１７及び下面電極１５を構成する導電材料は、特に制限されないが、アルミニウム（Al）、銀（Ag）、銅（Cu）、白金（Pt）、金（Au）、クロム（Cr）、ニッケル（Ni）、モリブデン（Mo）、タングステン(W)及びタンタル（Ta）等の金属から選択することが望ましい。もちろん、上面電極１７及び下面電極１５を構成する導電材料として合金を用いてもよい。また、複数種類の導電材料を重ねて成膜することにより、上面電極１７及び下面電極１５を形成してもよい。   The conductive material constituting the upper surface electrode 17 and the lower surface electrode 15 is not particularly limited, but aluminum (Al), silver (Ag), copper (Cu), platinum (Pt), gold (Au), chromium (Cr), nickel It is desirable to select from metals such as (Ni), molybdenum (Mo), tungsten (W) and tantalum (Ta). Of course, an alloy may be used as the conductive material constituting the upper electrode 17 and the lower electrode 15. Further, the upper surface electrode 17 and the lower surface electrode 15 may be formed by stacking a plurality of types of conductive materials.

上面電極１７１は、対向領域Ｅ１１において、圧電体薄膜２６を挟んで下面電極１５１と対向し、上面電極１７１及び下面電極１５１を駆動電極とする共振器（直列共振器）Ｒ１１を構成している。上面電極１７１は、対向領域Ｅ１１から＋Ｙ方向へ引き出された後に延伸方向が＋Ｘ方向及び−Ｙ方向へ順次折り曲げられ、引き出された部分の一部は、外部への配線が接続されるパットＰ１１となっている。   The upper surface electrode 171 is opposed to the lower surface electrode 151 across the piezoelectric thin film 26 in the facing region E11, and constitutes a resonator (series resonator) R11 having the upper surface electrode 171 and the lower surface electrode 151 as drive electrodes. The upper surface electrode 171 is pulled out from the opposing region E11 in the + Y direction, and then the extending direction is sequentially bent in the + X direction and the −Y direction, and a part of the extracted portion is connected to the pad P11 to which wiring to the outside is connected. It has become.

上面電極１７２は、対向領域Ｅ１２において、圧電体薄膜２６を挟んで下面電極１５２と対向し、上面電極１７２及び下面電極１５２を駆動電極とする共振器（並列共振器）Ｒ１２を構成している。上面電極１７２は、対向領域Ｅ１２から−Ｙ方向へ引き出された後に延伸方向が−Ｘ方向及び＋Ｙ方向へ順次折り曲げられ、引き出された部分の一部は、外部への配線が接続されるパットＰ１２及びＰ１４となっている。   The upper surface electrode 172 is opposed to the lower surface electrode 152 across the piezoelectric thin film 26 in the facing region E12, and constitutes a resonator (parallel resonator) R12 having the upper surface electrode 172 and the lower surface electrode 152 as drive electrodes. The upper surface electrode 172 is pulled out from the facing region E12 in the −Y direction, and then the extending direction is sequentially bent in the −X direction and the + Y direction, and a part of the extracted portion is a pad P12 to which wiring to the outside is connected. And P14.

上面電極１７３は、対向領域Ｅ１１及びＥ２２以外において、圧電体薄膜２６を挟んで下面電極１５３と対向している。上面電極１７３と下面電極１５３とはバイアホールＶＨ１によって導通しているので、圧電薄膜フィルタ１では、外部に露出した上面電極１７３を介して下面電極１５へ励振信号が給電される。上面電極１７３の一部は、外部への配線が接続されるパットＰ１３となっている。   The upper surface electrode 173 is opposed to the lower surface electrode 153 across the piezoelectric thin film 26 except in the opposed regions E11 and E22. Since the upper surface electrode 173 and the lower surface electrode 153 are electrically connected by the via hole VH1, in the piezoelectric thin film filter 1, an excitation signal is supplied to the lower surface electrode 15 through the upper surface electrode 173 exposed to the outside. A part of the upper surface electrode 173 is a pad P13 to which wiring to the outside is connected.

下面電極１５３は、下面電極１５１と下面電極１５２とを接続する配線電極であるとともに、共振器Ｒ１１及びＲ１２を音響的に分離する弾性波の障壁となっている。ここで、下面電極１５３は、下面電極１５１及び下面電極１５２との導通を確実に得るために、境界Ｂ１及びＢ２において下面電極１５１及び下面電極１５２とをわずかに重ねて成膜することが望ましい。   The lower surface electrode 153 is a wiring electrode that connects the lower surface electrode 151 and the lower surface electrode 152, and also serves as an elastic wave barrier that acoustically separates the resonators R11 and R12. Here, it is desirable that the lower surface electrode 153 is formed by slightly overlapping the lower surface electrode 151 and the lower surface electrode 152 at the boundaries B1 and B2 in order to reliably obtain conduction between the lower surface electrode 151 and the lower surface electrode 152.

圧電薄膜フィルタ１では、下面電極１５３の材質は、下面電極１５１及び１５２の材質と異なっている。したがって、圧電薄膜デバイス１においては、境界Ｂ１及びＢ２の両側で電極の材質、すなわち、弾性率及び密度が異なっており、境界Ｂ１及びＢ２は、音響インピーダンスが急激に変化する弾性波の反射端となっている。このような反射端Ｂ１及びＢ２により、圧電薄膜フィルタ１では、共振器Ｒ１１において励振された弾性波が共振器Ｒ１２へ到達することを妨げるとともに、共振器Ｒ１２において励振された弾性波が共振器Ｒ１１へ到達することを妨げ、共振器Ｒ１１及びＲ１２の干渉によるリップルの発生等の特性劣化を防止している。   In the piezoelectric thin film filter 1, the material of the lower surface electrode 153 is different from the material of the lower surface electrodes 151 and 152. Therefore, in the piezoelectric thin film device 1, the material of the electrode, that is, the elastic modulus and the density are different on both sides of the boundaries B1 and B2, and the boundaries B1 and B2 are the reflection end of the elastic wave whose acoustic impedance changes rapidly. It has become. Due to such reflection ends B1 and B2, in the piezoelectric thin film filter 1, the elastic wave excited in the resonator R11 is prevented from reaching the resonator R12, and the elastic wave excited in the resonator R12 is prevented from reaching the resonator R11. And the deterioration of characteristics such as the generation of ripples due to the interference of the resonators R11 and R12 is prevented.

さらに、圧電薄膜フィルタ１では、下面電極１５３の膜厚を下面電極１５１及び１５２の膜厚より厚くしている。これにより、圧電薄膜フィルタ１では、境界Ｂ１及びＢ２を超えて共振器Ｒ１１から共振器Ｒ１２へ向かう弾性波及び共振器Ｒ１２から共振器Ｒ１１へ向かう弾性波を下面電極１５３を構成する金属の粘性によって減衰させ、共振器Ｒ１１において励振された弾性波が共振器Ｒ１２へ到達することをさらに確実に妨げるとともに、共振器Ｒ１２において励振された弾性波が共振器Ｒ１１へ到達することをさらに確実に妨げている。このため、圧電薄膜フィルタ１では、駆動電極である上面電極１７１及び１７２並びに下面電極１５１及び１５２は、モリブデンやタングステンのような音響的な減衰が少ない材質で構成することが望ましい一方で、配線電極である下面電極１５３は、粘性が高い金属の膜で構成することが望ましく、粘性が特に高い金膜を含んで構成することが特に望ましい。ただし、圧電体薄膜１６と金膜との接着性が良好でない場合は、圧電体薄膜１６と金膜との間に他の金属の膜（例えば、クロム膜）を介在させて接着性を向上することが望ましい。   Further, in the piezoelectric thin film filter 1, the thickness of the lower surface electrode 153 is larger than the thickness of the lower surface electrodes 151 and 152. As a result, in the piezoelectric thin film filter 1, the elastic wave traveling from the resonator R 11 to the resonator R 12 and the elastic wave traveling from the resonator R 12 to the resonator R 11 across the boundaries B 1 and B 2 are caused by the viscosity of the metal constituting the lower surface electrode 153. Attenuating and further reliably preventing the elastic wave excited in the resonator R11 from reaching the resonator R12 and further reliably preventing the elastic wave excited in the resonator R12 from reaching the resonator R11. Yes. For this reason, in the piezoelectric thin film filter 1, it is desirable that the upper electrodes 171 and 172 and the lower electrodes 151 and 152 as drive electrodes are made of a material with low acoustic attenuation, such as molybdenum and tungsten. The lower surface electrode 153 is preferably formed of a highly viscous metal film, and particularly preferably includes a highly viscous gold film. However, when the adhesion between the piezoelectric thin film 16 and the gold film is not good, another metal film (for example, a chromium film) is interposed between the piezoelectric thin film 16 and the gold film to improve the adhesion. It is desirable.

加えて、圧電薄膜フィルタ１では、下面電極１５３の幅を下面電極１５１及び１５２の幅と同じにすることにより、対向領域Ｅ１１の内部の任意の点と対向領域Ｅ１２の内部の任意の点とを結ぶ直線が下面電極１５３を横断するようにしているので、共振器Ｒ１１及びＲ１２の干渉をより確実に防ぐことができる。   In addition, in the piezoelectric thin film filter 1, by making the width of the lower surface electrode 153 the same as the widths of the lower surface electrodes 151 and 152, an arbitrary point inside the opposing region E11 and an arbitrary point inside the opposing region E12 are obtained. Since the connecting straight line crosses the lower surface electrode 153, interference between the resonators R11 and R12 can be prevented more reliably.

このような上面電極１７及び下面電極１５により、圧電薄膜フィルタ１は、独立した共振器Ｒ１１及びＲ１２をモノリシックに一体化したラダー型のバンドパスフィルタとなっている。   Due to the upper surface electrode 17 and the lower surface electrode 15, the piezoelectric thin film filter 1 is a ladder-type bandpass filter in which independent resonators R 11 and R 12 are monolithically integrated.

＜１．４ 支持基板＞
支持基板１１は、圧電薄膜フィルタ１の製造途上で圧電体基板を除去加工するときに、下面電極１５及びキャビティ形成膜１３が下面に形成された圧電体基板を接着層１２を介して支持する支持体としての役割を有している。加えて、支持基板１１は、圧電薄膜フィルタ１の製造後に、下面電極１５及びキャビティ形成膜１３が下面に形成され、上面電極１７が上面に形成された圧電体薄膜１６を接着層１２を介して支持する支持体としての役割も有している。したがって、支持基板１１には、圧電体基板を除去加工するときに加わる力に耐え得ることと、圧電薄膜フィルタ１の製造後にも強度が低下しないこととが要請される。 <1.4 Support substrate>
The support substrate 11 supports the piezoelectric substrate on which the lower surface electrode 15 and the cavity forming film 13 are formed on the lower surface via the adhesive layer 12 when the piezoelectric substrate is removed during the manufacturing process of the piezoelectric thin film filter 1. Has a role as a body. In addition, after the piezoelectric thin film filter 1 is manufactured, the support substrate 11 has the piezoelectric thin film 16 having the lower surface electrode 15 and the cavity forming film 13 formed on the lower surface and the upper surface electrode 17 formed on the upper surface via the adhesive layer 12. It also has a role as a support to support. Accordingly, the support substrate 11 is required to be able to withstand the force applied when the piezoelectric substrate is removed, and not to decrease in strength even after the piezoelectric thin film filter 1 is manufactured.

支持基板１１の材料及び厚さは、このような要請を満足するように、適宜選択することができる。ただし、支持基板１１の材料を、圧電体薄膜１６を構成する圧電材料と近い熱膨張率、より望ましくは、圧電体薄膜１６を構成する圧電材料と同じ熱膨張率を有する材料、例えば、圧電体薄膜１６を構成する圧電材料と同じ材料とすれば、圧電薄膜フィルタ１の製造途上において、熱膨張率の差に起因する反りや破損を抑制することができ、圧電薄膜フィルタ１の製造後において、熱膨張率の差に起因する特性変動や破損を抑制することができる。なお、熱膨張率に異方性がある材料を用いる場合、圧電体薄膜１６と支持基板１１とで各方向の熱膨張率がともに同じとなるように配慮することが望ましく、支持基板１１と圧電体薄膜１６とに同じ圧電材料を用いる場合、支持基板１１と圧電体薄膜１６とで結晶方位を一致させることが望ましい。   The material and thickness of the support substrate 11 can be appropriately selected so as to satisfy such requirements. However, the material of the support substrate 11 is a material having a thermal expansion coefficient close to that of the piezoelectric material constituting the piezoelectric thin film 16, more preferably a material having the same thermal expansion coefficient as the piezoelectric material constituting the piezoelectric thin film 16, for example, a piezoelectric body If the same material as the piezoelectric material constituting the thin film 16 is used, warping and breakage due to the difference in thermal expansion coefficient can be suppressed during the manufacturing of the piezoelectric thin film filter 1, and after the piezoelectric thin film filter 1 is manufactured, Characteristic fluctuations and breakage due to the difference in thermal expansion coefficient can be suppressed. When a material having an anisotropic thermal expansion coefficient is used, it is desirable to consider that the piezoelectric thin film 16 and the support substrate 11 have the same thermal expansion coefficient in each direction. When the same piezoelectric material is used for the body thin film 16, it is desirable that the crystal orientations of the support substrate 11 and the piezoelectric thin film 16 are matched.

＜１．５ 接着層＞
接着層１２は、圧電薄膜フィルタ１の製造途上で圧電体基板を除去加工するときに、下面電極１５及びキャビティ形成膜１３が下面に形成された圧電体基板を支持基板１１に接着固定する役割を有している。加えて、接着層１２は、圧電薄膜フィルタ１の製造後に、下面電極１５及びキャビティ形成膜１３が下面に形成され、上面電極１６が上面に形成された圧電体薄膜１５を支持基板１１に接着固定する役割も有している。したがって、接着層１２には、圧電体基板を除去加工するときに加わる力に耐え得ることと、圧電薄膜フィルタ１の製造後にも接着力が低下しないこととが要請される。 <1.5 Adhesive layer>
The adhesive layer 12 serves to bond and fix the piezoelectric substrate having the lower surface electrode 15 and the cavity forming film 13 formed on the lower surface to the support substrate 11 when the piezoelectric substrate is removed during the manufacturing process of the piezoelectric thin film filter 1. Have. In addition, after the piezoelectric thin film filter 1 is manufactured, the adhesive layer 12 has the lower electrode 15 and the cavity forming film 13 formed on the lower surface, and the piezoelectric thin film 15 having the upper electrode 16 formed on the upper surface is bonded and fixed to the support substrate 11. It also has a role to play. Therefore, the adhesive layer 12 is required to be able to withstand the force applied when the piezoelectric substrate is removed and that the adhesive force does not decrease even after the piezoelectric thin film filter 1 is manufactured.

このような要請を満足する接着層１２の望ましい例としては、有機接着剤、望ましくは、充填効果を有し、接着対象が完全に平坦ではなくても十分な接着力を発揮するエポキシ接着剤（熱硬化性を利用するエポキシ樹脂の接着剤）やアクリル接着剤（光硬化性及び熱硬化性を併用するアクリル樹脂の接着剤）により形成された接着層１２を挙げることができる。このような樹脂を採用することにより、圧電体基板と支持基板１１との間に期待しない空隙が生じることを防止し、当該空隙により圧電体基板の除去加工時にクラック等が発生することを防止可能である。ただし、このことは、これ以外の接着層１２によって圧電体薄膜１５と支持基板１１とが接着固定されることを妨げるものではない。   Desirable examples of the adhesive layer 12 satisfying such requirements include an organic adhesive, preferably an epoxy adhesive having a filling effect and exhibiting sufficient adhesive force even if the object to be bonded is not completely flat ( Examples thereof include an adhesive layer 12 formed of an epoxy resin adhesive using thermosetting) and an acrylic adhesive (an acrylic resin adhesive using both photo-curing property and thermosetting property). By adopting such a resin, it is possible to prevent an unexpected gap from being generated between the piezoelectric substrate and the support substrate 11 and to prevent a crack or the like from being generated during the removal processing of the piezoelectric substrate by the gap. It is. However, this does not prevent the piezoelectric thin film 15 and the support substrate 11 from being bonded and fixed by the other adhesive layer 12.

＜１．６ キャビティ形成膜＞
キャビティ形成膜１３は、絶縁材料を成膜することにより得られた絶縁体膜である。キャビティ形成膜１３を構成する絶縁材料は、特に制限されないが、二酸化ケイ素（SiO2）等の絶縁材料から選択することが望ましい。 <1.6 Cavity forming film>
The cavity forming film 13 is an insulator film obtained by forming an insulating material. The insulating material constituting the cavity forming film 13 is not particularly limited, but is preferably selected from insulating materials such as silicon dioxide (SiO 2 ).

キャビティ形成膜１３は、圧電体薄膜１６の対向領域Ｅ１１及びＥ１２以外の領域に形成され、圧電体薄膜１６の対向領域Ｅ１１及びＥ１２を支持基板１１から離隔させるキャビティ（空洞）Ｃ１１及びＣ１２を形成している。   The cavity forming film 13 is formed in a region other than the opposing regions E11 and E12 of the piezoelectric thin film 16, and forms cavities C11 and C12 that separate the opposing regions E11 and E12 of the piezoelectric thin film 16 from the support substrate 11. ing.

＜実施例＞
以下では、本発明の望ましい実施形態に係る圧電薄膜フィルタ１に関する実施例について説明する。 <Example>
Below, the Example regarding the piezoelectric thin film filter 1 which concerns on desirable embodiment of this invention is demonstrated.

本実施例では、圧電体薄膜１６及び支持基板１１を構成する圧電材料としてニオブ酸リチウムの単結晶、キャビティ形成膜１３を構成する絶縁材料として二酸化ケイ素及び接着層１２を構成する材料としてエポキシ接着剤を用いて圧電薄膜フィルタ１を作製した。   In this embodiment, a single crystal of lithium niobate is used as the piezoelectric material constituting the piezoelectric thin film 16 and the support substrate 11, silicon dioxide is used as the insulating material constituting the cavity forming film 13, and an epoxy adhesive is used as the material constituting the adhesive layer 12. The piezoelectric thin film filter 1 was produced using

本実施例の圧電薄膜フィルタ１は、製造原価の低減のために、図５の断面図に示すように、多数（典型的には、数１００個〜数１０００個）の圧電薄膜フィルタ１を一体化した集合体Ｕ１を作製した後に、集合体Ｕ１をダイシングソーで切断して個々の圧電薄膜フィルタ１へ分離することによって得られている。   The piezoelectric thin film filter 1 of the present embodiment integrates a large number (typically several hundred to several thousand) of piezoelectric thin film filters 1 as shown in the sectional view of FIG. 5 in order to reduce the manufacturing cost. After the assembled assembly U1 is manufactured, the assembly U1 is cut with a dicing saw and separated into individual piezoelectric thin film filters 1.

以下では、便宜上、集合体Ｕ１に含まれる１個の圧電薄膜フィルタ１に着目して説明を進めるが、集合体Ｕ１に含まれる他の圧電薄膜フィルタ１も着目した圧電薄膜フィルタ１と同時平行して製造されている。   In the following, for the sake of convenience, the description will be focused on one piezoelectric thin film filter 1 included in the aggregate U1, but other piezoelectric thin film filters 1 included in the aggregate U1 are also parallel to the focused piezoelectric thin film filter 1. Manufactured.

続いて、図６〜図７の断面図を参照しながら、実施例に係る圧電薄膜フィルタ１の製造方法を説明する。   Then, the manufacturing method of the piezoelectric thin film filter 1 which concerns on an Example is demonstrated, referring sectional drawing of FIGS.

圧電薄膜フィルタ１の製造にあたっては、最初に、厚み０．５ｍｍ、直径３インチのニオブ酸リチウム単結晶の円形ウエハ（３６度カットＹ板）を圧電体基板１９及び支持基板１１として準備した。   In manufacturing the piezoelectric thin film filter 1, first, a circular wafer (36 ° cut Y plate) of lithium niobate single crystal having a thickness of 0.5 mm and a diameter of 3 inches was prepared as the piezoelectric substrate 19 and the support substrate 11.

そして、圧電体基板１９の下面の全面に膜厚７００オングストロームのタングステン膜をスパッタリングにより成膜し、一般的なフォトリソグラフィプロセスを用いてパターニングを行い下面電極１５１及び１５２を得た（図６（Ａ））。   Then, a tungsten film having a thickness of 700 angstroms was formed on the entire lower surface of the piezoelectric substrate 19 by sputtering, and patterning was performed using a general photolithography process to obtain lower surface electrodes 151 and 152 (FIG. 6A). )).

さらに、圧電体基板１９の下面の全面にに膜厚２００オングストロームのクロム膜と膜厚２０００オングストロームの金膜とをスパッタリングにより順次成膜し、一般的なフォトリソグラフィプロセスを用いてパターニングを行い下面電極１５３を得た（図６（Ｂ））。   Further, a chromium film having a film thickness of 200 angstroms and a gold film having a film thickness of 2000 angstroms are sequentially formed on the entire lower surface of the piezoelectric substrate 19 by sputtering, and patterning is performed using a general photolithography process to perform the lower electrode. 153 was obtained (FIG. 6B).

続いて、圧電体基板１９の下面の全面に膜厚１μｍの二酸化ケイ素膜をスパッタリングにより成膜し、圧電体基板１９を除去加工して得られる圧電体薄膜１６において対向領域Ｅ１１及びＥ１２となるべき領域に成膜された二酸化ケイ素膜をフッ酸を用いたウエットエッチングにより除去した。これにより、圧電体薄膜１６において対向領域Ｅ１１及びＥ１２となるべき領域以外にキャビティ形成膜１３が形成されたことになる（図６（Ｃ））。   Subsequently, a silicon dioxide film having a thickness of 1 μm is formed on the entire lower surface of the piezoelectric substrate 19 by sputtering, and the piezoelectric thin film 16 obtained by removing the piezoelectric substrate 19 should be opposed regions E11 and E12. The silicon dioxide film formed in the region was removed by wet etching using hydrofluoric acid. As a result, the cavity forming film 13 is formed in the piezoelectric thin film 16 in a region other than the regions to be the opposing regions E11 and E12 (FIG. 6C).

さらに続いて、支持基板１１の上面に接着層１２となるエポキシ接着剤を塗布し、支持基板１１の上面と、下面電極１５及びキャビティ形成膜１３が形成された圧電体基板１９の下面とを張り合わせた。そして、支持基板１１及び圧電体基板１９に圧力を印加してプレス圧着を行い、接着層１２の厚みを０．５μｍとした。しかる後に、張り合わせた支持基板１１及び圧電体基板１９とを２００℃の環境下で１時間放置してエポキシ接着剤を硬化させ、支持基板１１と圧電体基板１９を接着した。これにより、圧電体基板１９の、圧電体薄膜１６において対向領域Ｅ１１及びＥ１２となるべき領域の下方に、深さが約１μｍのキャビティＣ１１及びＣ１２が形成された（図６（Ｄ））。   Subsequently, an epoxy adhesive serving as an adhesive layer 12 is applied to the upper surface of the support substrate 11, and the upper surface of the support substrate 11 is bonded to the lower surface of the piezoelectric substrate 19 on which the lower surface electrode 15 and the cavity forming film 13 are formed. It was. Then, pressure was applied to the support substrate 11 and the piezoelectric substrate 19 to perform press-bonding, and the thickness of the adhesive layer 12 was set to 0.5 μm. Thereafter, the bonded support substrate 11 and piezoelectric substrate 19 were left in an environment of 200 ° C. for 1 hour to cure the epoxy adhesive, and the support substrate 11 and piezoelectric substrate 19 were bonded. As a result, cavities C11 and C12 having a depth of about 1 μm were formed below the region to be opposed regions E11 and E12 in the piezoelectric thin film 16 of the piezoelectric substrate 19 (FIG. 6D).

支持基板１１と圧電体基板１９との接着が完了した後、圧電体基板１９を支持基板１１に接着した状態を維持したまま、支持基板１１の下面を研磨治具に接着固定し、圧電体基板１９の上面を固定砥粒の研削機で研削加工し、圧電体基板１９の厚みを５０μｍまで薄肉化した。さらに、圧電体基板１９の上面をダイヤモンド砥粒で研磨加工し、圧電体基板１９の厚みを２μｍまで薄肉化した。最後に、ダイヤモンド砥粒による研磨加工で圧電体基板１９に生じた加工変質層を除去するために、遊離砥粒及び不繊布系研磨パッドを使用して圧電体基板１９の仕上げ研磨を行い、厚みが１．００μｍの圧電体薄膜１６を得た（図７（Ｅ））。   After the bonding between the support substrate 11 and the piezoelectric substrate 19 is completed, the lower surface of the support substrate 11 is bonded and fixed to the polishing jig while maintaining the state where the piezoelectric substrate 19 is bonded to the support substrate 11. The upper surface of 19 was ground with a fixed abrasive grinder to reduce the thickness of the piezoelectric substrate 19 to 50 μm. Further, the upper surface of the piezoelectric substrate 19 was polished with diamond abrasive grains to reduce the thickness of the piezoelectric substrate 19 to 2 μm. Finally, in order to remove the work-affected layer generated on the piezoelectric substrate 19 by polishing with diamond abrasive grains, the piezoelectric substrate 19 is subjected to final polishing using loose abrasive grains and a non-woven cloth polishing pad, A piezoelectric thin film 16 having a thickness of 1.00 μm was obtained (FIG. 7E).

次に、圧電体薄膜１６の上面（研磨面）を有機溶剤で洗浄し、膜厚が２００オングストロームのクロム膜と膜厚が２０００オングストロームの金膜とを圧電体薄膜１６の上面に順次成膜し、得られた積層膜を一般的なフォトリソグラフィプロセスを用いてパターニングすることにより、圧電体薄膜１６の、バイアホールＶＨ１を形成すべき部分のみを露出させたエッチングマスクＭ１を得た（図７（Ｆ））。   Next, the upper surface (polished surface) of the piezoelectric thin film 16 is washed with an organic solvent, and a chromium film having a thickness of 200 Å and a gold film having a thickness of 2000 Å are sequentially formed on the upper surface of the piezoelectric thin film 16. Then, by patterning the obtained laminated film using a general photolithography process, an etching mask M1 in which only a portion where the via hole VH1 of the piezoelectric thin film 16 is to be formed was exposed (FIG. 7 ( F)).

エッチングマスクＭ１の形成後、６５℃に加熱したバッファードフッ酸で圧電体薄膜１６のエッチングを行い、圧電体薄膜１６の上面と下面との間を貫通するバイアホールＶＨ１を形成して下面電極１５３を露出させるとともに、エッチングマスクＭ１をエッチングにより除去した（図７（Ｇ））。   After the formation of the etching mask M1, the piezoelectric thin film 16 is etched with buffered hydrofluoric acid heated to 65 ° C. to form a via hole VH1 penetrating between the upper surface and the lower surface of the piezoelectric thin film 16 to form the lower surface electrode 153. The etching mask M1 was removed by etching (FIG. 7G).

さらに、圧電体薄膜１６の上面の全面に厚み７００オングストロームのタングステン膜をスパッタリングにより成膜し、一般的なフォトリソグラフィプロセスを用いてパターニングを行い、上面電極１７を得た（図７（Ｈ））。このとき、バイアホールＶＨ１の内側面にもタングステン膜が形成されるので、上面電極１７１と下面電極１５との導通が確保される。   Further, a tungsten film having a thickness of 700 angstroms was formed on the entire upper surface of the piezoelectric thin film 16 by sputtering, and patterning was performed using a general photolithography process to obtain the upper surface electrode 17 (FIG. 7H). . At this time, since the tungsten film is also formed on the inner side surface of the via hole VH1, conduction between the upper surface electrode 171 and the lower surface electrode 15 is ensured.

このようにして得られた圧電薄膜フィルタ１の濾波特性を評価したところ、実用上問題となるようなリップルはなく、挿入損失も小さいことがわかった。   When the filtering characteristics of the piezoelectric thin film filter 1 obtained in this way were evaluated, it was found that there was no ripple that would cause a practical problem and the insertion loss was small.

＜比較例＞
本発明の範囲外の比較例では、下面電極１５３を膜厚が７００オングストロームのタングステン膜とし、下面電極１５１及び１５２と同時に下面電極１５３を形成した以外は実施例と同様の手順で圧電薄膜フィルタを作製した。このようにして得られた圧電薄膜フィルタの濾波特性を評価したところ、実用上問題となるようなリップルが観察され、挿入損失も大きいことがわかった。 <Comparative example>
In a comparative example outside the scope of the present invention, the piezoelectric thin film filter was formed in the same procedure as in the example except that the lower electrode 153 was a tungsten film having a thickness of 700 Å and the lower electrode 153 was formed simultaneously with the lower electrodes 151 and 152. Produced. When the filtering characteristics of the piezoelectric thin film filter thus obtained were evaluated, it was found that ripples that would be a practical problem were observed and that the insertion loss was also large.

本発明の望ましい実施形態に係る圧電薄膜フィルタ１の斜視図である。1 is a perspective view of a piezoelectric thin film filter 1 according to a preferred embodiment of the present invention. 本発明の望ましい実施形態に係る圧電薄膜フィルタ１の平面図である。1 is a plan view of a piezoelectric thin film filter 1 according to a preferred embodiment of the present invention. 図１のIII-IIIの切断線における圧電薄膜フィルタ１の断面を示す断面図である。It is sectional drawing which shows the cross section of the piezoelectric thin film filter 1 in the cutting line of III-III of FIG. 圧電薄膜フィルタ１に含まれる２個の共振器Ｒ１１及びＲ１２の電気的な接続を示す回路図である。3 is a circuit diagram showing electrical connection of two resonators R11 and R12 included in the piezoelectric thin film filter 1. FIG. 多数の圧電薄膜フィルタ１を一体化した集合体Ｕ１を切断して個々の圧電薄膜フィルタ１へ分離する様子を示す図である。It is a figure which shows a mode that the aggregate | assembly U1 which integrated many piezoelectric thin film filters 1 is cut | disconnected and isolate | separated into each piezoelectric thin film filter 1. FIG. 実施例に係る圧電薄膜フィルタ１の製造方法を説明する図である。It is a figure explaining the manufacturing method of the piezoelectric thin film filter 1 which concerns on an Example. 実施例に係る圧電薄膜フィルタ１の製造方法を説明する図である。It is a figure explaining the manufacturing method of the piezoelectric thin film filter 1 which concerns on an Example. 従来の圧電薄膜フィルタ９の斜視図である。It is a perspective view of the conventional piezoelectric thin film filter.

符号の説明Explanation of symbols

１ 圧電薄膜フィルタ
１１ 支持基板
１２ 接着層
１３ キャビティ形成膜
１５ 下面電極
１６ 圧電体薄膜
１７ 上面電極
１７１，１７２ 上面電極（駆動電極）
１７３ 上面電極（配線電極） DESCRIPTION OF SYMBOLS 1 Piezoelectric thin film filter 11 Support substrate 12 Adhesive layer 13 Cavity formation film 15 Lower surface electrode 16 Piezoelectric thin film 17 Upper surface electrode 171, 172 Upper surface electrode (drive electrode)
173 Top electrode (wiring electrode)

Claims (4)

圧電体薄膜と、
第１対向領域において前記圧電体薄膜を挟んで対向するように前記圧電体薄膜の第１主面及び第２主面にそれぞれ形成され、第１共振器を構成する第１駆動電極及び第２駆動電極と、
第２対向領域において前記圧電体薄膜を挟んで対向するように前記圧電体薄膜の第１主面及び第２主面にそれぞれ形成され、第２共振器を構成する第３駆動電極及び第４駆動電極と、
前記第１主面に形成され、前記第１駆動電極と前記第３駆動電極とを接続する配線電極と、
を備え、
前記第１駆動電極と前記配線電極との境界及び前記第３駆動電極と前記配線電極との境界の両側で電極の材質が異なる圧電薄膜デバイス。 A piezoelectric thin film;
A first drive electrode and a second drive, which are formed on the first main surface and the second main surface of the piezoelectric thin film so as to face each other with the piezoelectric thin film interposed therebetween in the first opposing region, and constitute the first resonator. Electrodes,
A third drive electrode and a fourth drive are formed on the first main surface and the second main surface of the piezoelectric thin film so as to face each other with the piezoelectric thin film interposed therebetween in the second facing region, and constitute a second resonator. Electrodes,
A wiring electrode formed on the first main surface and connecting the first drive electrode and the third drive electrode;
With
A piezoelectric thin film device in which electrode materials are different on both sides of a boundary between the first drive electrode and the wiring electrode and a boundary between the third drive electrode and the wiring electrode. 前記配線電極の膜厚が前記第１駆動電極及び前記第３駆動電極の膜厚より厚い請求項１に記載の圧電薄膜デバイス。   2. The piezoelectric thin film device according to claim 1, wherein a film thickness of the wiring electrode is larger than a film thickness of the first drive electrode and the third drive electrode. 前記配線電極が金膜を含む請求項１又は請求項２に記載の圧電薄膜デバイス。   The piezoelectric thin film device according to claim 1, wherein the wiring electrode includes a gold film. 前記第１対向領域の内部の任意の点と前記第２対向領域の内部の任意の点とを結ぶ直線が前記配線電極を横断する請求項１ないし請求項３のいずれかに記載の圧電薄膜デバイス。   4. The piezoelectric thin film device according to claim 1, wherein a straight line connecting an arbitrary point inside the first opposing region and an arbitrary point inside the second opposing region crosses the wiring electrode. 5. .
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JP2017022501A (en) * 2015-07-08 2017-01-26 太陽誘電株式会社 Acoustic wave device, branching filter, and module
WO2023248558A1 (en) * 2022-06-22 2023-12-28 株式会社村田製作所 Elastic wave device

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JP2004104449A (en) * 2002-09-09 2004-04-02 Fujitsu Media Device Kk Filter, filter unit and manufacturing method therefor
JP2004120494A (en) * 2002-09-27 2004-04-15 Tdk Corp Thin film piezo-resonator, filter and duplexer using the same, and method of manufacturing thin film piezo-resonator
JP2005110230A (en) * 2003-09-12 2005-04-21 Matsushita Electric Ind Co Ltd Thin film bulk acoustic resonator, method for producing same, filter, composite electronic component device, and communication apparatus

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Publication number Priority date Publication date Assignee Title
JP2004104449A (en) * 2002-09-09 2004-04-02 Fujitsu Media Device Kk Filter, filter unit and manufacturing method therefor
JP2004120494A (en) * 2002-09-27 2004-04-15 Tdk Corp Thin film piezo-resonator, filter and duplexer using the same, and method of manufacturing thin film piezo-resonator
JP2005110230A (en) * 2003-09-12 2005-04-21 Matsushita Electric Ind Co Ltd Thin film bulk acoustic resonator, method for producing same, filter, composite electronic component device, and communication apparatus

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017022501A (en) * 2015-07-08 2017-01-26 太陽誘電株式会社 Acoustic wave device, branching filter, and module
WO2023248558A1 (en) * 2022-06-22 2023-12-28 株式会社村田製作所 Elastic wave device

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