JP2001168674A - Piezoelectric resonance element and electronic appliance - Google Patents
Piezoelectric resonance element and electronic applianceInfo
- Publication number
- JP2001168674A JP2001168674A JP35058599A JP35058599A JP2001168674A JP 2001168674 A JP2001168674 A JP 2001168674A JP 35058599 A JP35058599 A JP 35058599A JP 35058599 A JP35058599 A JP 35058599A JP 2001168674 A JP2001168674 A JP 2001168674A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- piezoelectric
- substrate
- piezoelectric thin
- temperature coefficient
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は圧電共振子及び電子
機器に関し、特に、圧電体層の弾性振動を利用した圧電
共振子と当該圧電共振子を利用した電子機器に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric resonator and an electronic device, and more particularly, to a piezoelectric resonator using elastic vibration of a piezoelectric layer and an electronic device using the piezoelectric resonator.
【０００２】[0002]
【従来の技術】圧電基板の厚み振動を利用した圧電薄膜
共振子の共振周波数は、圧電基板の厚さに反比例し、超
高周波領域では圧電基板を極めて薄く加工する必要があ
る。しかし、圧電基板自体の厚さを薄くするのは、その
機械的強度や取り扱い上の制限などから、基本モードで
は数１００ＭＨｚが実用上の高周波限界とされてきた。
このような問題を解決するため、従来より圧電薄膜共振
子が提案されており、フィルタや共振器として提案され
ている。2. Description of the Related Art The resonance frequency of a piezoelectric thin-film resonator utilizing the thickness vibration of a piezoelectric substrate is inversely proportional to the thickness of the piezoelectric substrate. However, the thickness of the piezoelectric substrate itself has been reduced to a practical high frequency limit of several hundred MHz in the fundamental mode due to its mechanical strength and restrictions on handling.
In order to solve such a problem, a piezoelectric thin film resonator has been conventionally proposed, and is proposed as a filter or a resonator.
【０００３】図１は高周波特性を伸ばせるようにした圧
電薄膜共振子１を示す断面図であって、微細加工法を用
いてＳｉ基板２を部分的にエッチングすることにより、
Ｓｉ基板２の一部に数μｍ以下の厚さの薄膜支持部３を
形成し、その上に一対の励振用電極５ａ，５ｂを有する
ＺｎＯ圧電薄膜４を設けたものである。FIG. 1 is a cross-sectional view showing a piezoelectric thin-film resonator 1 capable of extending high-frequency characteristics. The piezoelectric thin-film resonator 1 is formed by partially etching a Si substrate 2 using a fine processing method.
A thin film supporting portion 3 having a thickness of several μm or less is formed on a part of a Si substrate 2, and a ZnO piezoelectric thin film 4 having a pair of excitation electrodes 5a and 5b is provided thereon.
【０００４】また、図２に示す圧電薄膜共振子６では、
Ｓｉ基板２の表面に熱酸化等によってＳｉＯ２薄膜７を
形成し、Ｓｉ基板２を部分的にエッチングすることによ
ってＳｉＯ２薄膜７で薄膜支持部３を形成し、その上に
励振用電極５ａ，５ｂを両面に有するＺｎＯ圧電薄膜４
を設けている。In the piezoelectric thin film resonator 6 shown in FIG.
The SiO 2 thin film 7 is formed on the surface of the Si substrate 2 by thermal oxidation or the like, and the Si substrate 2 is partially etched to form the thin film support portion 3 with the SiO 2 thin film 7, on which the excitation electrodes 5 a, Piezoelectric thin film 4 having 5b on both sides
Is provided.
【０００５】図１及び図２のような圧電薄膜共振子１、
６では、薄膜支持部３は微細加工技術を用いて薄くする
ことができ、圧電薄膜４もスパッタリング等によって薄
く形成することができるので、数１００ＭＨｚ〜数１０
００ＭＨｚまで高周波特性を延ばすことができる可能性
がある。A piezoelectric thin film resonator 1 shown in FIGS.
In (6), since the thin film support portion 3 can be thinned by using a fine processing technique, and the piezoelectric thin film 4 can also be formed thin by sputtering or the like, several hundred MHz to several tens of MHz.
There is a possibility that high-frequency characteristics can be extended up to 00 MHz.
【０００６】また、ＺｎＯの弾性定数の温度係数（ＴＣ
Ｆ）は約−７０ppm／℃、Ｓｉの弾性定数の温度係数は
約−３０ppm／℃であって、ＺｎＯとＳｉでは弾性定数
の温度係数がいずれも負の値をもつので、ＺｎＯからな
る圧電薄膜４とＳｉからなる薄膜支持部３との組み合わ
せを有する図１の圧電薄膜共振子１では、基本モードに
おける共振周波数の温度特性が悪くなる恐れがある。こ
れに対し、ＺｎＯの弾性定数の温度係数は約−７０ppm
／℃、ＳｉＯ２の弾性定数の温度係数は約＋１００ppm
／℃であって、ＺｎＯとＳｉＯ２では弾性定数の温度係
数の符号が異なるので、図２の圧電薄膜共振子では、Ｚ
ｎＯからなる圧電薄膜４の膜厚とＳｉＯ ２からなる薄膜
支持部３の膜厚との比をある適当な値（概略で、２：
１）に設定することにより、基本モードにおける共振周
波数の温度係数を小さくし、共振周波数の温度特性を安
定にすることができる（特開昭５８−１２１８１７号公
報）。Further, the temperature coefficient of the elastic constant of ZnO (TC
F) is about -70 ppm / ° C., and the temperature coefficient of the elastic constant of Si is
About -30 ppm / ° C. Elastic constant for ZnO and Si
Has a negative value, the temperature coefficient of
Combination of the piezoelectric thin film 4 and the thin film support 3 made of Si
In the piezoelectric thin-film resonator 1 shown in FIG.
There is a possibility that the temperature characteristics of the resonance frequency may be deteriorated. This
On the other hand, the temperature coefficient of the elastic constant of ZnO is about -70 ppm.
/ ℃, SiO2The temperature coefficient of elastic constant is about + 100ppm
/ ° C, ZnO and SiO2Then the temperature constant of the elastic constant
Since the signs of the numbers are different, in the piezoelectric thin film resonator of FIG.
Film thickness of piezoelectric thin film 4 made of nO and SiO 2Consisting of thin film
The ratio with the film thickness of the support portion 3 is set to an appropriate value (approximately 2:
By setting to 1), the resonance frequency in the fundamental mode
Reduce the temperature coefficient of the wave number and reduce the temperature characteristics of the resonance frequency.
(JP-A-58-121817)
Information).
【０００７】[0007]
【発明が解決しようとする課題】しかしながら、図１の
ような構造の圧電薄膜共振子では、半導体であるＳｉ基
板を用いているため、励振用電極とＳｉ基板との間の浮
遊容量及びＳｉ基板自体を経由して励振用電極間で高周
波信号の漏れが発生し、高い反共振特性が得られないと
いう問題があった。However, in the piezoelectric thin film resonator having the structure shown in FIG. 1, since the Si substrate which is a semiconductor is used, the floating capacitance between the excitation electrode and the Si substrate and the Si substrate Leakage of a high-frequency signal occurs between the excitation electrodes via itself, and there is a problem that high anti-resonance characteristics cannot be obtained.
【０００８】また、図２のような構造の圧電薄膜共振子
でも、半導体であるシリコン基板を用いているので、励
振用電極とシリコン基板との間の浮遊容量、Ｓｉ基板及
びＳｉ基板と励振用電極との間の浮遊容量を経由して励
振用電極間で高周波信号の漏れが発生し、高い反共振特
性が得られないという問題があった。In the piezoelectric thin-film resonator having the structure shown in FIG. 2, the silicon substrate which is a semiconductor is used, so that the floating capacitance between the excitation electrode and the silicon substrate, the Si substrate and the Si substrate and the excitation Leakage of a high-frequency signal occurs between the excitation electrodes via the stray capacitance between the electrodes, and there is a problem that high anti-resonance characteristics cannot be obtained.
【０００９】本発明は上述の技術的問題点を解決するた
めになされたものであり、その目的とするところは、共
振周波数の温度特性が安定で、かつ反共振特性も良好な
圧電薄膜による圧電共振子及び電子機器を提供すること
にある。The present invention has been made to solve the above-mentioned technical problems, and an object of the present invention is to provide a piezoelectric thin film having a stable temperature characteristic of resonance frequency and good anti-resonance characteristics. It is to provide a resonator and an electronic device.
【００１０】[0010]
【課題を解決するための手段とその作用】本発明にかか
る圧電共振子は、絶縁材料もしくは圧電材料からなる基
板の一部を裏面側からエッチングすることによって該基
板の表面の一部に薄膜部分を形成し、該薄膜部分の上に
１層もしくは複数層の圧電体層と電極とからなる圧電素
子部を設けた圧電共振子であって、前記圧電体層のうち
少なくとも１層における弾性定数の温度係数の正負符号
が、前記薄膜部分における弾性定数の温度係数の正負符
号と異なっていることを特徴としている。A piezoelectric resonator according to the present invention is characterized in that a part of a substrate made of an insulating material or a piezoelectric material is etched from the back side to form a thin film part on a part of the surface of the substrate. And a piezoelectric resonator comprising one or more piezoelectric layers and electrodes on the thin film portion, wherein the piezoelectric element has an elastic constant of at least one of the piezoelectric layers. The sign of the temperature coefficient is different from the sign of the temperature coefficient of the elastic constant in the thin film portion.
【００１１】本発明にかかる圧電共振子にあっては、圧
電体層のうち少なくとも１層における弾性定数の温度係
数の正負符号が、薄膜部分における弾性定数の温度係数
の正負符号と異なっているので、圧電共振子全体として
の弾性定数の温度係数を小さくすることができる。しか
も、基板が絶縁材料もしくは圧電材料からなるので、圧
電素子部の電極間で高周波信号が漏れるのを防止でき、
強い反共振特性を得ることができる。In the piezoelectric resonator according to the present invention, the sign of the temperature coefficient of the elastic constant in at least one of the piezoelectric layers is different from the sign of the temperature coefficient of the elastic constant in the thin film portion. In addition, the temperature coefficient of the elastic constant of the entire piezoelectric resonator can be reduced. Moreover, since the substrate is made of an insulating material or a piezoelectric material, it is possible to prevent a high frequency signal from leaking between the electrodes of the piezoelectric element portion,
Strong anti-resonance characteristics can be obtained.
【００１２】さらに、基板の薄膜部は裏面側から基板を
エッチングすることによって形成されているので、薄膜
部を基板に接合させたりする方法に比較して容易に薄膜
部を形成することができ、コストダウンを図ることがで
きる。Further, since the thin film portion of the substrate is formed by etching the substrate from the back side, the thin film portion can be easily formed as compared with a method of bonding the thin film portion to the substrate. Cost can be reduced.
【００１３】例えば、基板の材料としては、水晶、Ｌｉ
ＮｂＯ３、ＬｉＴａＯ３、ＰｂＴｉＯ３、ＰＺＴのうち
いずれかを主成分とするものを用いることができる。For example, the material of the substrate is quartz, Li
A material containing any one of NbO 3 , LiTaO 3 , PbTiO 3 , and PZT as a main component can be used.
【００１４】また、弾性定数の温度係数が負である圧電
体層としては、ＺｎＯ、ＬｉＮｂＯ ３、ＬｉＴａＯ３、
ＰｂＺｒＸＴｉ（１−Ｘ）Ｏ３〔０≦ｘ≦０.５２〕の
いずれかの圧電材料を主成分とするものを用いることが
でき、主としてこれらの圧電体層を用いる場合には、弾
性定数の温度係数が正の基板を用いればよい。A piezoelectric element having a negative temperature coefficient of elastic constant.
For the body layer, ZnO, LiNbO 3, LiTaO3,
PbZrXTi(1-X)O3[0 ≦ x ≦ 0.52]
It is possible to use one that contains any piezoelectric material as the main component.
When these piezoelectric layers are mainly used,
A substrate having a positive temperature coefficient of a sex constant may be used.
【００１５】また、弾性定数の温度係数が正である圧電
体層としては、ＡｌＮ、ＰｂＺｒＸＴｉ（１−Ｘ）Ｏ３
〔０.５４≦ｘ≦１〕を主成分とするものを用いること
ができ、主としてこれらの圧電体層を用いる場合には、
弾性定数の温度係数が負の基板を用いればよい。[0015] As the piezoelectric layer temperature coefficient of elastic constant is positive, AlN, PbZr X Ti (1 -X) O 3
A material having [0.54 ≦ x ≦ 1] as a main component can be used. When these piezoelectric layers are mainly used,
A substrate having a negative temperature coefficient of elastic constant may be used.
【００１６】また、本発明の圧電共振子を用いて電子機
器を構成することができる。Further, an electronic device can be configured using the piezoelectric resonator of the present invention.
【００１７】[0017]
【発明の実施の形態】（第１の実施形態）図３は本発明
の第１の実施形態による圧電薄膜共振子２１の構造を示
す断面図である。この圧電薄膜共振子２１にあっては、
水晶基板２２を裏面側からエッチングすることによって
水晶基板２２の裏面に空洞２４を形成し、その上面に水
晶基板２２の一部からなる薄膜支持部２３を形成してい
る。薄膜支持部２３の上面には、ＰＺＴからなる圧電薄
膜２５と圧電薄膜２５下面の励振用電極２６ａと圧電薄
膜２５上面の励振用電極２６ｂとからなる圧電素子部２
７が形成されている。(First Embodiment) FIG. 3 is a sectional view showing the structure of a piezoelectric thin film resonator 21 according to a first embodiment of the present invention. In this piezoelectric thin film resonator 21,
By etching the quartz substrate 22 from the back surface side, a cavity 24 is formed on the back surface of the quartz substrate 22, and a thin film support portion 23 formed of a part of the quartz substrate 22 is formed on the upper surface thereof. On the upper surface of the thin film support portion 23, a piezoelectric element portion 2 including a piezoelectric thin film 25 made of PZT, an excitation electrode 26a on the lower surface of the piezoelectric thin film 25, and an excitation electrode 26b on the upper surface of the piezoelectric thin film 25
7 are formed.
【００１８】図４（ａ）〜（ｄ）及び図５（ｅ）〜
（ｈ）は上記圧電薄膜共振子２１の製造工程の概略を示
す図である。まず、水晶基板２２を用意し、水晶基板２
２の上にフォトレジスト２８を塗布し、フォトリソグラ
フィによりフォトレジスト２８をパターニングして図４
（ａ）のように下層の励振用電極パターンの開口２９を
あける。ついで、図４（ｂ）に示すように、フォトレジ
スト２８の上から電極用金属３０を蒸着やスパッタ等に
よって堆積させた後、フォトレジスト２８を剥離させる
ことにより、図４（ｃ）に示すように、リフトオフ法で
下層の励振用電極２６ａを形成する。FIGS. 4 (a) to 4 (d) and 5 (e) to 5 (e).
(H) is a figure which shows the outline of the manufacturing process of the said piezoelectric thin film resonator 21. First, the crystal substrate 22 is prepared, and the crystal substrate 2 is prepared.
2 is coated on top of the photoresist 2, and the photoresist 28 is patterned by photolithography.
An opening 29 of the lower excitation electrode pattern is opened as shown in FIG. Next, as shown in FIG. 4B, after the electrode metal 30 is deposited on the photoresist 28 by vapor deposition, sputtering, or the like, the photoresist 28 is peeled off, as shown in FIG. 4C. Then, a lower excitation electrode 26a is formed by a lift-off method.
【００１９】この後、図４（ｄ）に示すように水晶基板
２２の上にメタルマスク３１を用いてスパッタによりＰ
ＺＴパターンを水晶基板２２の上に堆積させ、図５
（ｅ）に示すように圧電薄膜２５を形成する。Thereafter, as shown in FIG. 4 (d), P is formed on the quartz substrate 22 by sputtering using a metal mask 31.
A ZT pattern is deposited on the quartz substrate 22, and FIG.
The piezoelectric thin film 25 is formed as shown in FIG.
【００２０】つづけて、圧電薄膜２５の上から水晶基板
２２の表面にフォトレジスト３２を塗布し、フォトリソ
グラフィによりフォトレジスト３２をパターニングして
上層の励振用電極パターンの開口３３をあける。つい
で、図５（ｆ）に示すように、フォトレジスト３２の上
から電極用金属３４を蒸着やスパッタ等によって堆積さ
せた後、フォトレジスト３２を剥離させることにより、
図５（ｇ）に示すように、リフトオフ法で上層の励振用
電極２６ｂを形成する。Subsequently, a photoresist 32 is applied to the surface of the quartz substrate 22 from above the piezoelectric thin film 25, and the photoresist 32 is patterned by photolithography to form an opening 33 of an upper excitation electrode pattern. Next, as shown in FIG. 5F, after depositing a metal for electrode 34 from above the photoresist 32 by vapor deposition or sputtering, the photoresist 32 is peeled off.
As shown in FIG. 5G, the upper-layer excitation electrode 26b is formed by a lift-off method.
【００２１】この後、マスクを用いてウェットエッチン
グあるいはリアクティブ・イオンエッチング（ＲＩＥ）
により水晶基板２２を裏面側から部分的にエッチングす
ることにより、図５（ｈ）に示すように水晶基板２２の
裏面に凹部２４を形成し、その表面側に圧電薄膜２５を
形成する。Thereafter, wet etching or reactive ion etching (RIE) is performed using a mask.
By partially etching the quartz substrate 22 from the back surface side, a concave portion 24 is formed on the back surface of the quartz substrate 22 as shown in FIG. 5H, and the piezoelectric thin film 25 is formed on the front surface side.
【００２２】このような構造の圧電薄膜共振子２１にあ
っては、圧電薄膜２５であるＰＺＴの弾性定数の温度係
数が負であるのに対し、薄膜支持部２３である水晶の弾
性定数の温度係数は正であるので、圧電薄膜２５の膜厚
と薄膜支持部２３の膜厚を適当に設定すれば、圧電薄膜
共振子２１の温度係数をほぼゼロにすることができる。In the piezoelectric thin film resonator 21 having such a structure, while the temperature coefficient of the elastic constant of the PZT as the piezoelectric thin film 25 is negative, the temperature of the elastic constant of the quartz as the thin film support portion 23 is lower. Since the coefficient is positive, by appropriately setting the film thickness of the piezoelectric thin film 25 and the film thickness of the thin film support portion 23, the temperature coefficient of the piezoelectric thin film resonator 21 can be made substantially zero.
【００２３】また、上記のように下面側からエッチング
することによって薄膜支持部２３を形成しているので、
孔をあけた基板の上に同じ材質の薄板を接合させ、研磨
する方法などに比較すると、容易に薄膜支持部を得るこ
とができる。Further, since the thin film support portion 23 is formed by etching from the lower surface side as described above,
A thin film support can be easily obtained as compared with a method in which a thin plate of the same material is joined to a substrate having a hole and polished.
【００２４】さらに、基板２２が圧電体（絶縁体）であ
る水晶によって形成されており、水晶の比抵抗は約１０
１６Ω・ｃｍとシリコンの比抵抗が約１０３Ω・ｃｍで
あるのに対して非常に値が大きいので、両励振用電極２
６ａ、２６ｂ間を電気的に確実に絶縁することができ、
両励振用電極２６ａ、２６ｂ間における高周波信号の漏
れを防止でき、圧電薄膜共振子２１の反共振特性を良好
にでき、反共振点における特性曲線を鋭くできる。Further, the substrate 22 is formed of quartz which is a piezoelectric body (insulator), and the specific resistance of the quartz is about 10
Since the specific resistance of silicon is about 10 3 Ω · cm, which is very large, while the specific resistance of silicon is about 16 Ω · cm, the dual excitation electrode 2 is used.
6a and 26b can be electrically insulated reliably.
Leakage of a high-frequency signal between the two excitation electrodes 26a and 26b can be prevented, the anti-resonance characteristics of the piezoelectric thin-film resonator 21 can be improved, and the characteristic curve at the anti-resonance point can be sharpened.
【００２５】なお、ここでは水晶基板に対して圧電薄膜
としてＰＺＴを用いたが、ＰＺＴに代えてＬｉＮｂ
Ｏ３、ＬｉＴａＯ３、ＰｂＴｉＯ３等の圧電体を用いて
もよい。Although PZT is used here as the piezoelectric thin film for the quartz substrate, LiNb is used instead of PZT.
A piezoelectric material such as O 3 , LiTaO 3 , and PbTiO 3 may be used.
【００２６】（第２の実施形態）図６は本発明の第２の
実施形態による圧電薄膜共振子４１の構造を示す断面図
である。この圧電薄膜共振子４１にあっては、ＬｉＮｂ
Ｏ３からなる基板４２を裏面側からエッチングすること
によって基板４２の裏面に空洞４４を形成し、その上面
に基板４２の一部からなる薄膜支持部４３を形成してい
る。薄膜支持部４３の上面には、ＡｌＮからなる圧電薄
膜４５と圧電薄膜４５下面の励振用電極４６ａと圧電薄
膜４５上面の励振用電極４６ｂとからなる圧電素子部４
７が形成されている。(Second Embodiment) FIG. 6 is a sectional view showing the structure of a piezoelectric thin film resonator 41 according to a second embodiment of the present invention. In this piezoelectric thin film resonator 41, LiNb
The substrate 42 made of O 3 a cavity 44 is formed on the back surface of the substrate 42 by etching from the back side to form a thin film support portion 43 consisting of a portion of the substrate 42 on its upper surface. On the upper surface of the thin film support portion 43, a piezoelectric element portion 4 composed of a piezoelectric thin film 45 made of AlN, an excitation electrode 46a on the lower surface of the piezoelectric thin film 45, and an excitation electrode 46b on the upper surface of the piezoelectric thin film 45 is provided.
7 are formed.
【００２７】このような構造の圧電薄膜共振子４１にあ
っても下面側から基板４２をエッチングすることによっ
て薄膜支持部４３を形成しているので、薄膜支持部４３
を容易に得ることができる。Even in the piezoelectric thin film resonator 41 having such a structure, the thin film supporting portion 43 is formed by etching the substrate 42 from the lower surface side.
Can be easily obtained.
【００２８】また、圧電薄膜４５であるＡｌＮの弾性定
数の温度係数が正であるのに対し、薄膜支持部４３であ
るＬｉＮｂＯ３の弾性定数の温度係数は負であるので、
圧電薄膜４５の膜厚と薄膜支持部４３の膜厚を適当に設
定すれば、圧電薄膜共振子４１の温度係数をほぼゼロに
することができる。Further, the temperature coefficient of the elastic constant of AlN as the piezoelectric thin film 45 is positive, while the temperature coefficient of the elastic constant of LiNbO 3 as the thin film support 43 is negative.
By appropriately setting the thickness of the piezoelectric thin film 45 and the thickness of the thin film support 43, the temperature coefficient of the piezoelectric thin film resonator 41 can be made substantially zero.
【００２９】さらに、基板が圧電体（絶縁体）であるＬ
ｉＮｂＯ３によって形成されているので、両励振用電極
４６ａ、４６ｂ間を電気的に確実に絶縁することがで
き、両励振用電極４６ａ、４６ｂ間における高周波信号
の漏れを防止でき、圧電薄膜共振子４１の反共振特性を
良好にでき、反共振点における特性曲線を鋭くできる。Further, the substrate L is a piezoelectric material (insulator).
Since it is formed of iNbO 3 , it is possible to electrically insulate the electrodes 46a and 46b reliably from each other, prevent leakage of a high-frequency signal between the electrodes 46a and 46b, and obtain a piezoelectric thin film resonator. 41 can have good anti-resonance characteristics, and can sharpen the characteristic curve at the anti-resonance point.
【００３０】なお、ここでは基板としてＬｉＮｂＯ３を
用いたが、代わりにＬｉＴａＯ３、ＰｂＴｉＯ３等の圧
電体を用いてもよい。また、比抵抗が約１０１０Ω・ｃ
ｍ以上の絶縁体を基板として用いてもよい。Although LiNbO 3 is used as the substrate here, a piezoelectric material such as LiTaO 3 or PbTiO 3 may be used instead. The specific resistance is about 10 10 Ω · c
m or more insulators may be used as the substrate.
【００３１】（第３の実施形態）図７は本発明の第３の
実施形態による圧電薄膜共振子５１の構造を示す断面図
である。この圧電薄膜共振子５１にあっては、水晶基板
５２を裏面側からエッチングすることによって水晶基板
５２の裏面に空洞５４を形成し、その上面に基板５２の
一部からなる薄膜支持部５３を形成している。薄膜支持
部５３の上面には、ＺｎＯからなる複数層の圧電薄膜５
５と励振用電極５６ａ、５６ｂとが交互に積層され、各
励振用電極５６ａどうしを接続し、各励振用電極５６ｂ
どうしも接続して圧電素子部５７が形成されている。(Third Embodiment) FIG. 7 is a sectional view showing the structure of a piezoelectric thin film resonator 51 according to a third embodiment of the present invention. In this piezoelectric thin-film resonator 51, a cavity 54 is formed on the back surface of the quartz substrate 52 by etching the quartz substrate 52 from the back surface side, and a thin film support portion 53 composed of a part of the substrate 52 is formed on the upper surface thereof. are doing. On the upper surface of the thin film support 53, a plurality of piezoelectric thin films 5 made of ZnO are provided.
5 and the excitation electrodes 56a and 56b are alternately laminated, and the respective excitation electrodes 56a are connected to each other, and the respective excitation electrodes 56b
The piezoelectric element portion 57 is formed by being connected to each other.
【００３２】このような構造の圧電薄膜共振子５１にあ
っても第１及び第２の実施形態と同様な作用効果を奏す
るが、さらに、圧電薄膜５５が複数層に形成されている
ので、共振レスポンスをさらに高くすることができる。The piezoelectric thin-film resonator 51 having such a structure has the same operation and effect as those of the first and second embodiments. However, since the piezoelectric thin-films 55 are formed in a plurality of layers, resonance occurs. The response can be further improved.
【００３３】なお、この実施形態でも基板材料や圧電薄
膜材料は、上記実施形態で用いた材料の組み合わせを用
いることもできる。In this embodiment, as the substrate material and the piezoelectric thin film material, a combination of the materials used in the above embodiment can be used.
【００３４】（第４の実施形態）図８は本発明の第４の
実施形態による圧電薄膜共振子６１の構造を示す断面図
である。この圧電薄膜共振子６１にあっては、水晶基板
６２を裏面側からエッチングすることによって水晶基板
６２の裏面に空洞６４を形成し、その上面に基板６２の
一部からなる薄膜支持部６３を形成している。薄膜支持
部６３の上面には、下層の励振用電極６７ａ、ＺｎＯか
らなる圧電薄膜６５、ＡｌＮからなる圧電薄膜励振用電
極６６、上層の励振用電極６７ｂとが積層されて圧電素
子部６８が形成されている。(Fourth Embodiment) FIG. 8 is a sectional view showing the structure of a piezoelectric thin film resonator 61 according to a fourth embodiment of the present invention. In this piezoelectric thin-film resonator 61, a cavity 64 is formed on the back surface of the quartz substrate 62 by etching the quartz substrate 62 from the back surface side, and a thin film support portion 63 formed of a part of the substrate 62 is formed on the upper surface thereof. are doing. On the upper surface of the thin-film support portion 63, a lower-layer excitation electrode 67a, a piezoelectric thin-film 65 made of ZnO, a piezoelectric thin-film excitation electrode 66 made of AlN, and an upper-layer excitation electrode 67b are laminated to form a piezoelectric element portion 68. Have been.
【００３５】このような構造の圧電薄膜共振子６１にあ
っても第１及び第２の実施形態と同様な作用効果を奏す
る。また、この実施形態は、複数材質の圧電薄膜６５、
６６を積層した点を特徴としており、ＺｎＯの弾性定数
の温度係数は負、ＡｌＮの弾性定数の温度係数は正、水
晶の弾性定数の温度係数が正であるので、圧電薄膜共振
子６１の共振周波数の温度係数をゼロにするためのパラ
メータが増加して設計が容易になる。The piezoelectric thin film resonator 61 having such a structure has the same operation and effect as those of the first and second embodiments. In addition, this embodiment includes a piezoelectric thin film 65 of a plurality of materials,
The temperature coefficient of the elastic constant of ZnO is negative, the temperature coefficient of the elastic constant of AlN is positive, and the temperature coefficient of the elastic constant of quartz is positive. The parameter for setting the temperature coefficient of the frequency to zero is increased and the design becomes easy.
【００３６】なお、この実施形態でも上記圧電薄膜材料
と異なる材料で各圧電薄膜を形成してもよく、上記基板
材料と異なる材料の基板を用いてもよい。In this embodiment, each piezoelectric thin film may be formed of a material different from the above-mentioned piezoelectric thin film material, or a substrate made of a material different from the above-mentioned substrate material may be used.
【図１】従来の圧電薄膜共振子の構造を示す断面図であ
る。FIG. 1 is a cross-sectional view showing the structure of a conventional piezoelectric thin film resonator.
【図２】弾性定数の温度特性を改善した従来の別な圧電
薄膜共振子の構造を示す断面図である。FIG. 2 is a cross-sectional view showing the structure of another conventional piezoelectric thin film resonator in which the temperature characteristic of the elastic constant is improved.
【図３】本発明の第１の実施形態による圧電薄膜共振子
の構造を示す断面図である。FIG. 3 is a sectional view showing the structure of the piezoelectric thin film resonator according to the first embodiment of the present invention.
【図４】（ａ）〜（ｄ）は同上の圧電薄膜共振子の製造
工程を説明する概略図である。FIGS. 4A to 4D are schematic views for explaining a manufacturing process of the piezoelectric thin-film resonator according to the first embodiment.
【図５】（ｅ）〜（ｈ）は、図４（ａ）〜（ｄ）の続図
である。5 (e) to (h) are continuation diagrams of FIGS. 4 (a) to (d).
【図６】本発明の第２の実施形態による圧電薄膜共振子
の構造を示す断面図である。FIG. 6 is a sectional view showing a structure of a piezoelectric thin-film resonator according to a second embodiment of the present invention.
【図７】本発明の第３の実施形態による圧電薄膜共振子
の構造を示す断面図である。FIG. 7 is a sectional view showing a structure of a piezoelectric thin-film resonator according to a third embodiment of the present invention.
【図８】本発明の第４の実施形態による圧電薄膜共振子
の構造を示す断面図である。FIG. 8 is a sectional view showing a structure of a piezoelectric thin-film resonator according to a fourth embodiment of the present invention.
２１、４１ 圧電薄膜共振子 ２２ 水晶基板 ４２ ＬｉＮｂＯ３基板 ２３、４３ 薄膜支持部 ２５ ＰＺＴ圧電薄膜 ４５ ＡｌＮ圧電薄膜 ２６ａ、２６ｂ、４６ａ、４６ｂ 励振用電極 ２７、４７ 圧電素子部21 and 41 the piezoelectric thin film resonator 22 quartz substrate 42 LiNbO 3 substrate 23, 43 a thin film support portion 25 PZT piezoelectric thin film 45 AlN piezoelectric thin film 26a, 26b, 46a, 46b excitation electrodes 27, 47 piezoelectric element
───────────────────────────────────────────────────── フロントページの続き (72)発明者 竹内 雅樹 京都府長岡京市天神二丁目26番10号 株式 会社村田製作所内 Ｆターム(参考） 5J108 AA04 BB04 BB07 CC04 CC11 EE03 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masaki Takeuchi 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto F-term in Murata Manufacturing Co., Ltd. 5J108 AA04 BB04 BB07 CC04 CC11 EE03
Claims (5)
の一部を裏面側からエッチングすることによって該基板
の表面の一部に薄膜部分を形成し、該薄膜部分の上に１
層もしくは複数層の圧電体層と電極とからなる圧電素子
部を設けた圧電共振子であって、 前記圧電体層のうち少なくとも１層における弾性定数の
温度係数の正負符号が、前記薄膜部分における弾性定数
の温度係数の正負符号と異なっていることを特徴とする
圧電共振子。1. A thin film portion is formed on a part of a surface of a substrate made of an insulating material or a piezoelectric material by etching a portion of the substrate from the back surface side, and a thin film portion is formed on the thin film portion.
A piezoelectric resonator provided with a piezoelectric element portion including one or more piezoelectric layers and electrodes, wherein at least one of the piezoelectric layers has a positive or negative sign of a temperature coefficient of an elastic constant in the thin film portion. A piezoelectric resonator characterized in that the temperature coefficient of the elastic constant is different from the sign of the temperature coefficient.
ＴａＯ３、ＰｂＴｉＯ３、ＰＺＴのうちいずれかを主成
分とするものであることを特徴とする、請求項１に記載
の圧電共振子。2. The substrate is made of quartz, LiNbO 3 , Li
2. The piezoelectric resonator according to claim 1, wherein one of TaO 3 , PbTiO 3 , and PZT is a main component. 3.
は、ＺｎＯ、ＬｉＮｂＯ３、ＬｉＴａＯ３、ＰｂＺｒＸ
Ｔｉ（１−Ｘ）Ｏ３〔０≦ｘ≦０.５２〕のいずれかの
圧電材料を主成分として構成されていることを特徴とす
る、請求項１又は２に記載の圧電共振子。3. The piezoelectric layer having a negative temperature coefficient of elastic constant is made of ZnO, LiNbO 3 , LiTaO 3 , PbZr X
The piezoelectric resonator according to claim 1, wherein the piezoelectric resonator is mainly composed of any one of Ti (1-X) O 3 [0 ≦ x ≦ 0.52].
は、ＡｌＮ、ＰｂＺｒＸＴｉ（１−Ｘ）Ｏ３〔０.５４
≦ｘ≦１〕を主成分として構成されていることを特徴と
する、請求項１又は２に記載の圧電共振子。4. A piezoelectric layer temperature coefficient is positive elastic constants, AlN, PbZr X Ti (1 -X) O 3 [0.54
≦ x ≦ 1] as the main component.
載の圧電共振子を用いて構成したことを特徴とする電子
機器。5. An electronic device comprising the piezoelectric resonator according to claim 1. Description:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35058599A JP2001168674A (en) | 1999-12-09 | 1999-12-09 | Piezoelectric resonance element and electronic appliance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35058599A JP2001168674A (en) | 1999-12-09 | 1999-12-09 | Piezoelectric resonance element and electronic appliance |
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| Publication Number | Publication Date |
|---|---|
| JP2001168674A true JP2001168674A (en) | 2001-06-22 |
Family
ID=18411485
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP35058599A Pending JP2001168674A (en) | 1999-12-09 | 1999-12-09 | Piezoelectric resonance element and electronic appliance |
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| Country | Link |
|---|---|
| JP (1) | JP2001168674A (en) |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003060478A (en) * | 2001-08-17 | 2003-02-28 | Murata Mfg Co Ltd | Piezoelectric thin-film resonator, manufacturing method thereof, and filter and electronic device using the piezoelectric thin-film resonator |
| US6870445B2 (en) * | 2002-03-28 | 2005-03-22 | Kabushiki Kaisha Toshiba | Thin film bulk acoustic wave resonator |
| US7002437B2 (en) | 2002-06-11 | 2006-02-21 | Murata Manufacturing Co., Ltd. | Piezoelectric thin-film resonator, piezoelectric filter, and electronic component including the piezoelectric filter |
| WO2006027873A1 (en) * | 2004-09-10 | 2006-03-16 | Murata Manufacturing Co., Ltd. | Thin film piezoelectric resonator |
| US7161447B2 (en) | 2002-09-25 | 2007-01-09 | Murata Manufacturing Co., Ltd. | Piezoelectric resonator, piezoelectric filter, and communication apparatus |
| US7180390B2 (en) | 2003-08-12 | 2007-02-20 | Murata Manufacturing Co., Ltd. | Electronic component and method for manufacturing the same |
| US7245060B2 (en) | 2004-09-24 | 2007-07-17 | Murata Manufacturing Co., Ltd. | Piezoelectric resonator, method for manufacturing the same, piezoelectric filter, and duplexer |
| US7276994B2 (en) | 2002-05-23 | 2007-10-02 | Murata Manufacturing Co., Ltd. | Piezoelectric thin-film resonator, piezoelectric filter, and electronic component including the piezoelectric filter |
| US7320164B2 (en) | 2002-01-10 | 2008-01-22 | Murata Manufacturing Co., Ltd. | Method of manufacturing an electronic component |
| US7414349B2 (en) | 2002-10-28 | 2008-08-19 | Matsushita Electric Industrial Co., Ltd. | Piezoelectric vibrator, filter using the same and its adjusting method |
| US20100107387A1 (en) * | 2004-04-06 | 2010-05-06 | Samsung Electronics Co., Ltd. | Bulk acoustic wave resonator, filter and duplexer and methods of making same |
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1999
- 1999-12-09 JP JP35058599A patent/JP2001168674A/en active Pending
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003060478A (en) * | 2001-08-17 | 2003-02-28 | Murata Mfg Co Ltd | Piezoelectric thin-film resonator, manufacturing method thereof, and filter and electronic device using the piezoelectric thin-film resonator |
| US7320164B2 (en) | 2002-01-10 | 2008-01-22 | Murata Manufacturing Co., Ltd. | Method of manufacturing an electronic component |
| US6870445B2 (en) * | 2002-03-28 | 2005-03-22 | Kabushiki Kaisha Toshiba | Thin film bulk acoustic wave resonator |
| US7276994B2 (en) | 2002-05-23 | 2007-10-02 | Murata Manufacturing Co., Ltd. | Piezoelectric thin-film resonator, piezoelectric filter, and electronic component including the piezoelectric filter |
| US7002437B2 (en) | 2002-06-11 | 2006-02-21 | Murata Manufacturing Co., Ltd. | Piezoelectric thin-film resonator, piezoelectric filter, and electronic component including the piezoelectric filter |
| US7161447B2 (en) | 2002-09-25 | 2007-01-09 | Murata Manufacturing Co., Ltd. | Piezoelectric resonator, piezoelectric filter, and communication apparatus |
| US7414349B2 (en) | 2002-10-28 | 2008-08-19 | Matsushita Electric Industrial Co., Ltd. | Piezoelectric vibrator, filter using the same and its adjusting method |
| US7180390B2 (en) | 2003-08-12 | 2007-02-20 | Murata Manufacturing Co., Ltd. | Electronic component and method for manufacturing the same |
| US20100107387A1 (en) * | 2004-04-06 | 2010-05-06 | Samsung Electronics Co., Ltd. | Bulk acoustic wave resonator, filter and duplexer and methods of making same |
| WO2006027873A1 (en) * | 2004-09-10 | 2006-03-16 | Murata Manufacturing Co., Ltd. | Thin film piezoelectric resonator |
| US7327209B2 (en) | 2004-09-10 | 2008-02-05 | Murata Manufacturing Co., Ltd. | Piezoelectric thin film resonator |
| US7245060B2 (en) | 2004-09-24 | 2007-07-17 | Murata Manufacturing Co., Ltd. | Piezoelectric resonator, method for manufacturing the same, piezoelectric filter, and duplexer |
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