JPS6142891B2 - - Google Patents
Info
- Publication number
- JPS6142891B2 JPS6142891B2 JP13488477A JP13488477A JPS6142891B2 JP S6142891 B2 JPS6142891 B2 JP S6142891B2 JP 13488477 A JP13488477 A JP 13488477A JP 13488477 A JP13488477 A JP 13488477A JP S6142891 B2 JPS6142891 B2 JP S6142891B2
- Authority
- JP
- Japan
- Prior art keywords
- insulating film
- electrode
- acoustic wave
- surface acoustic
- input
- 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.)
- Expired
Links
- 239000000463 material Substances 0.000 claims description 31
- 238000010897 surface acoustic wave method Methods 0.000 claims description 28
- 239000000758 substrate Substances 0.000 claims description 16
- 239000011521 glass Substances 0.000 claims description 10
- 239000012212 insulator Substances 0.000 description 19
- 238000000034 method Methods 0.000 description 10
- 229920002120 photoresistant polymer Polymers 0.000 description 10
- 239000002184 metal Substances 0.000 description 9
- 238000004519 manufacturing process Methods 0.000 description 8
- 229910004298 SiO 2 Inorganic materials 0.000 description 6
- 238000000605 extraction Methods 0.000 description 5
- 230000008878 coupling Effects 0.000 description 4
- 238000010168 coupling process Methods 0.000 description 4
- 238000005859 coupling reaction Methods 0.000 description 4
- 230000007547 defect Effects 0.000 description 4
- 239000011810 insulating material Substances 0.000 description 3
- 230000010354 integration Effects 0.000 description 3
- 229910013641 LiNbO 3 Inorganic materials 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 238000001259 photo etching Methods 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910004261 CaF 2 Inorganic materials 0.000 description 1
- 239000004962 Polyamide-imide Substances 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000005566 electron beam evaporation Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 229920002312 polyamide-imide Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 238000000992 sputter etching Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02818—Means for compensation or elimination of undesirable effects
- H03H9/02921—Measures for preventing electric discharge due to pyroelectricity
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/08—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of resonators or networks using surface acoustic waves
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02228—Guided bulk acoustic wave devices or Lamb wave devices having interdigital transducers situated in parallel planes on either side of a piezoelectric layer
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02543—Characteristics of substrate, e.g. cutting angles
- H03H9/02574—Characteristics of substrate, e.g. cutting angles of combined substrates, multilayered substrates, piezoelectrical layers on not-piezoelectrical substrate
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02637—Details concerning reflective or coupling arrays
- H03H9/02653—Grooves or arrays buried in the substrate
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Description
【発明の詳細な説明】
本発明は弾性表面波素子に関するものであり、
超高周波用表面波素子を歩留りよく提供すること
を目的とする。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface acoustic wave element,
The purpose is to provide surface acoustic wave devices for ultra-high frequencies with a high yield.
従来の弾性表面波素子の構造は、第１図および
第２図に示すように、圧電体１（例えば、PZT
板，LiNbO3板，水晶等）の上に、交叉形櫛歯状
電極による入力トランスデユーサ３と出力トラン
スデユーサ４を設け、入力トランスデユーサ３に
より、入力電気信号を弾性表面波に変換し、圧電
基板１上を伝播した弾性表面波は出力トランスデ
ユーサ４により、出力電気信号に変換される。こ
の時、交叉型電極の各電極幅の間隔によつて弾性
表面波の波長が決定され、入力及び出力トランス
デユーサの間隔によつて、遅延時間が決定され、
目的に応じたフイルター素子、遅延素子等を得る
ことができる。 As shown in FIGS. 1 and 2, the structure of a conventional surface acoustic wave element includes a piezoelectric material 1 (for example, PZT
An input transducer 3 and an output transducer 4 using intersecting comb-shaped electrodes are installed on top of the board (LiNbO 3 board, crystal, etc.), and the input transducer 3 converts the input electrical signal into a surface acoustic wave. However, the surface acoustic wave propagated on the piezoelectric substrate 1 is converted into an output electric signal by the output transducer 4. At this time, the wavelength of the surface acoustic wave is determined by the interval between the electrode widths of the crossed electrodes, and the delay time is determined by the interval between the input and output transducers.
Filter elements, delay elements, etc. can be obtained depending on the purpose.
ここで、弾性表面波素子においては、圧電体上
に、櫛歯状の電極を微細加工法（ホトエツチング
加工）を用いて形成することが必要であり、しか
も、数百ＭHz〜数ＧHz帯に用いられる弾性表面波
素子にいては、それぞれの櫛歯状電極の幅と、そ
の間隔においては数μｍ、もしくはそれ以下の寸
法の微細加工が必要となり、しかも櫛歯状電極対
が多くなると、それぞれの電極間での電気的短絡
や、断線欠陥が発生し、表面波素子としての性能
を満足しない結果となる。 Here, in surface acoustic wave elements, it is necessary to form comb-shaped electrodes on a piezoelectric material using a microfabrication method (photoetching process), and moreover, it is necessary to form comb-like electrodes on a piezoelectric material using a microfabrication method (photoetching process). In the surface acoustic wave device, the width of each comb-shaped electrode and the interval between them require microfabrication of several micrometers or less, and as the number of pairs of comb-shaped electrodes increases, each Electrical short circuits and disconnection defects occur between the electrodes, resulting in unsatisfactory performance as a surface wave element.
本発明は、弾性表面波素子において、櫛歯状電
極の製作を容易にするとともに、前記した櫛歯状
電極に発生しやすい欠陥が発生しにくくした弾性
表面波素子を提供するものである。また本発明に
よる構造を用いた他の特徴としては、素子として
の温度系数を小さくすることができること、ま
た、従来の素子の微細加工時に用いている同一の
ホトマスクを用いて、従来の２倍の集積度の電極
形成が可能であるため、特に超高周波領域に用い
る弾性表面波素子を製作する際に利点となる。 The present invention provides a surface acoustic wave element in which the comb-shaped electrodes are easily manufactured and the defects that tend to occur in the comb-shaped electrodes described above are less likely to occur. In addition, other features of the structure according to the present invention include that the temperature coefficient of the element can be reduced, and that the same photomask that is used in the microfabrication of conventional elements can be used to process twice as much as the conventional one. Since it is possible to form electrodes with a high degree of integration, this is an advantage particularly when manufacturing surface acoustic wave elements used in the ultra-high frequency region.
以下本発明の一実施例を図面を用いて説明す
る。まず、第１の実施例を第３図、第４図を用い
て説明すると、圧電体１（例えばPZT，
LiNbO3，水晶等）上に、入出力トランスデユー
サの一方向電極５Ａ，７Ａのみを形成し、この圧
電体１及び電極５Ａ，７Ａ上全面に絶縁膜６を形
成し、この絶縁膜６上に、入出力トランスデユー
サの残り一方向電極５Ｂ，７Ｂを形成する。この
構造によれば入出力トランスデユーサのそれぞれ
において一方向電極を形成した後に絶縁物を介し
て、他の一方向電極を形成しているため、たとえ
最初に形成した一方向電極に電気的短絡部分が発
生していても、その電極上に形成した絶縁物６に
よつて、絶縁物６上に形成した第２の電極と前記
一方向電極とが電気的短絡することがなく、製作
上有利である。次に、本発明の構造をもつ弾性表
面波素子を製作する一方法を第５図イ〜チを用い
て説明する。まず、第５図イに示すように、圧電
体１（例えば、PZT，LiNbO3，水晶等）上に、
ロに示すように、金属膜８（例えば、クロム―金
膜，アルミ膜等）を真空蒸着法等の手段により、
膜厚が0.1〜0.5μｍ程度に均一に形成する。次
に、ハに示すように、金属膜８上にホトレジスト
膜パターン９を形成する。この時ホトレジスト膜
パターンはネガタイプホトレジストを用いる場合
であれば、第７図に示すホトマスクを用いてパタ
ーン形成を行なえば良い。また、ここで形成する
ホトレジスト膜パターンは、入出力トランスジユ
ーサとなる櫛歯状電極の一方向のみで良いため、
第７図に示すホトマスクは、従来、圧電体に平面
的に櫛歯状電極を製作する際に用いられる第６図
に示すホトマスクより、櫛歯状ストライプの１ピ
ツチ寸法Ａが、２倍で良いことになる。このこと
は、ホトマスクを製作することが容易になると同
時に、ホトレジスト膜パターンを製作する時も同
様に容易となる。しかも、本発明の構造によれば
ホトレジスト膜パターンに、ストライプの短絡及
び断線が発生していても一向に素子としては不良
品にならないことも、製作歩留まりの面から大き
な利点である。また、従来よりも櫛歯状ストライ
プの１ピツチが２倍になると云うことは、従来と
同一寸法のホトマスクを用いると、従来より２倍
の集積密度にて櫛歯状電極を形成することが可能
になり、表面波素子の電極微細化が容易になる。 An embodiment of the present invention will be described below with reference to the drawings. First, the first embodiment will be explained using FIGS. 3 and 4. The piezoelectric body 1 (for example, PZT,
Only the unidirectional electrodes 5A and 7A of the input/output transducer are formed on the piezoelectric material 1 and the electrodes 5A and 7A, and an insulating film 6 is formed on the entire surface of the piezoelectric body 1 and the electrodes 5A and 7A. Then, the remaining unidirectional electrodes 5B and 7B of the input/output transducer are formed. According to this structure, after forming a unidirectional electrode in each input/output transducer, another unidirectional electrode is formed via an insulator, so even if the first unidirectional electrode formed is electrically shorted, Even if a portion occurs, the insulator 6 formed on the electrode prevents an electrical short circuit between the second electrode formed on the insulator 6 and the one-way electrode, which is advantageous in manufacturing. It is. Next, one method of manufacturing a surface acoustic wave device having the structure of the present invention will be explained using FIGS. First, as shown in FIG . 5A, a
As shown in FIG.
Form a uniform film with a thickness of about 0.1 to 0.5 μm. Next, as shown in (c), a photoresist film pattern 9 is formed on the metal film 8. At this time, if a negative type photoresist is used as the photoresist film pattern, the pattern may be formed using a photomask shown in FIG. In addition, the photoresist film pattern formed here only needs to be in one direction for the comb-like electrodes that will become the input/output transducer.
In the photomask shown in FIG. 7, the pitch dimension A of the comb-like stripes can be twice as large as that of the photomask shown in FIG. It turns out. This not only makes it easier to fabricate a photomask, but also makes it easier to fabricate a photoresist film pattern. Moreover, according to the structure of the present invention, even if short circuits and disconnections occur in stripes in the photoresist film pattern, the device will not be defective at all, which is a great advantage in terms of manufacturing yield. In addition, the pitch of the comb-shaped stripes is twice that of the conventional one, which means that using a photomask with the same dimensions as before, it is possible to form comb-shaped electrodes at twice the integration density than before. This makes it easier to miniaturize the electrodes of surface wave devices.
ホトレジスト膜パターン９は、圧電体１上に形
成した金属膜８の不要部分を取除くように、形成
し、次に、不要な金属膜を取除くため、酸、もし
くはアルカリ性の溶液によるエツチング法、スパ
ツタエツチング法等の手段により、金属膜をエツ
チングする。次にニに示すようにホトレジスト膜
９を、金属膜上から取除き、次に、圧電体１及び
電極上８全面に、スパツタリング法，CVD法，
電子ビーム蒸着法等の手段により、絶縁膜１０
（例えば、Ａ2O3，SiO，SiO2，MgF2，CaF2
等）を膜厚として約0.1〜0.5μｍ程度形成する
（第５図ホ）。次にヘに示すように絶縁膜１０上
に、再度金属膜１１を膜厚0.1〜0.5μｍ程度に形
成する。次に、第５図ハで説明した方法と同様
に、金属膜１１上に形成した電極の中間にホトレ
ジスト膜パターン１２がくるように位置合わせを
行ない第５図トの如く形成する（ただし、表面波
素子としては、圧電板１上に形成した第１電極８
と絶縁膜１０上の第２電極１１との相対位置関係
は、相互の水平平行度が保たれるならば、水平方
向の位置関係はズレが生じても構わない）。次に
第５図チに示すようにホトレジスト膜パターン１
２をマスク（保護膜）として金属膜１１の不要部
分を前に述べた方法と同様にエツチングする。次
に金属膜ストライプ上からホトレジスト膜を取除
き、第５図チに示す本発明の構造をもつ弾性表面
波素子が完成する。 The photoresist film pattern 9 is formed so as to remove unnecessary parts of the metal film 8 formed on the piezoelectric body 1, and then an etching method using an acid or alkaline solution is used to remove the unnecessary metal film. The metal film is etched by means such as sputter etching. Next, as shown in d, the photoresist film 9 is removed from the metal film, and then the piezoelectric body 1 and the entire surface of the electrode 8 are coated by sputtering method, CVD method, etc.
The insulating film 10 is formed by means such as electron beam evaporation.
(For example, A 2 O 3 , SiO, SiO 2 , MgF 2 , CaF 2
etc.) with a film thickness of about 0.1 to 0.5 μm (Fig. 5 E). Next, as shown in F, a metal film 11 is again formed on the insulating film 10 to a thickness of about 0.1 to 0.5 μm. Next, in the same way as the method explained in FIG. As a wave element, a first electrode 8 formed on a piezoelectric plate 1 is used.
The relative positional relationship between the second electrode 11 on the insulating film 10 may be shifted in the horizontal direction as long as mutual horizontal parallelism is maintained). Next, as shown in FIG.
Using 2 as a mask (protective film), unnecessary portions of the metal film 11 are etched in the same manner as described above. Next, the photoresist film is removed from the metal film stripe to complete a surface acoustic wave device having the structure of the present invention shown in FIG.
次に第２の実施例を第８図イ〜ロを用いて説明
する。まず、第８図イに示すように、圧電体１上
に、入出力トランスデユーサの一方向電極と同一
形状の絶縁物１３（例えば、SiO，SiO2膜等）を
膜厚が0.1〜0.5μｍ程度になるように形成し、そ
の絶縁物１３上に櫛形電極の一方向電極１４を形
成し、その後、第８図ロに示すように、圧電体１
全面に絶縁膜SiO，SiO2等）１０を、絶縁膜１３
と同一程度の厚み（0.1〜0.5μｍ）に形成し、そ
の後、櫛形電極の他の一方向電極１５をその絶縁
膜１０上に、先に形成した一方向電極１４の中間
位置に形成する。この方法によれば、圧電体１上
に同一膜厚の絶縁物を介して、入出力トランンス
デユーサ電極１４，１５が形成されるため、例え
ば、圧電体１と絶縁膜１３，１０のそれぞれの温
度係数を相殺関係になるように選んでおくことに
よつて、（例えば、圧電体としてLiNbO3板，絶縁
物としてSiO2膜）、素子として温度係数を小さく
することができる。また、圧電体と電極との中間
に絶縁物が介入した構造となるため、特に圧電体
の電気―機械結合系数が大きい材料を用いる場
合、この結合系数を下げることができるため、不
要信号の低減に効果がある。また、誘電率の高い
材料を用いた場合に問題があつた出力インピーダ
ンスの低下も、圧電体と電極との間に誘電率の低
い絶縁物が介入するため、素子としての出力イン
ピーダンスを上げることができ、回路との結合が
より改善される。しかも、絶縁膜１０は、櫛歯状
電極の第１の一方向電極１４上を覆うように形成
するため第１の一方向電極１４及び、第２の一方
向電極１５それぞれにおいて、電極の櫛形パター
ン部に電気的短格部が発生しても、第１と第２と
が電気的短絡を発生することはなく、製作歩留ま
りが向上するとともに、製作が容易である。 Next, a second embodiment will be explained using FIG. 8 (a) to (b). First, as shown in FIG. 8A, an insulator 13 (for example, SiO, SiO 2 film, etc.) having the same shape as the unidirectional electrode of the input/output transducer is placed on the piezoelectric body 1 to a thickness of 0.1 to 0.5. A unidirectional comb-shaped electrode 14 is formed on the insulator 13, and then, as shown in FIG.
An insulating film (SiO, SiO 2, etc.) 10 is applied to the entire surface, and an insulating film 13 is applied to the entire surface.
After that, another unidirectional comb-shaped electrode 15 is formed on the insulating film 10 at an intermediate position between the previously formed unidirectional electrode 14. According to this method, the input/output transducer electrodes 14 and 15 are formed on the piezoelectric body 1 through the insulating material having the same film thickness. By selecting the elements so that their temperature coefficients cancel each other out (for example, using a LiNbO 3 plate as the piezoelectric material and a SiO 2 film as the insulator), the temperature coefficient of the element can be reduced. In addition, since the structure has an insulator interposed between the piezoelectric body and the electrode, especially when using a material with a large electrical-mechanical coupling coefficient for the piezoelectric body, this coupling coefficient can be lowered, reducing unnecessary signals. is effective. In addition, the output impedance decrease, which was a problem when using materials with a high dielectric constant, can be resolved by intervening an insulator with a low dielectric constant between the piezoelectric material and the electrode, making it possible to increase the output impedance of the element. This improves the connection with the circuit. Moreover, since the insulating film 10 is formed so as to cover the first unidirectional electrode 14 which is a comb-shaped electrode, the comb-shaped electrode pattern is formed in each of the first unidirectional electrode 14 and the second unidirectional electrode 15. Even if an electrical short occurs in the first and second parts, an electrical short will not occur between the first and second parts, improving manufacturing yield and making manufacturing easy.
次に本発明の第３の実施例を第９図を用いて説
明する。まず、圧電体１上に、圧電体１の温度係
数を相殺する関係の物質（例えば、圧電体１とし
て、LiTaO3板を用いるならば、SiO3膜）１６を
圧電体１上に形成する。この物質１６（絶縁膜）
上に、本発明の構造をもつ、入出力トランスデユ
ーサの櫛形電極の一方向電極１４を形成し、この
上に、絶縁膜１０（例えば、SiO，SiO2等）を形
成し、この上に、櫛形電極の残り一方向電極１５
を、第一に形成した一方向電極１４の中間位置に
形成する。この構造においても、第２の実施例で
示したのと同様な効果がある。 Next, a third embodiment of the present invention will be described using FIG. 9. First, on the piezoelectric body 1, a substance 16 having a relationship that cancels out the temperature coefficient of the piezoelectric body 1 (for example, if a LiTaO 3 plate is used as the piezoelectric body 1, a SiO 3 film) 16 is formed. This substance 16 (insulating film)
A unidirectional comb-shaped electrode 14 of an input/output transducer having the structure of the present invention is formed on top of the unidirectional electrode 14, and an insulating film 10 (for example, SiO, SiO 2 , etc.) is formed on top of this. , the remaining one-way electrode 15 of the comb-shaped electrode
is formed at an intermediate position of the unidirectional electrode 14 formed first. This structure also has the same effects as shown in the second embodiment.
次に第４の実施例を第１０図を用いて説明す
る。第１０図の実施例の構造は、圧電板１上に、
入出力トランスデユーサのそれぞれの櫛形電極の
一方向電極１４と、絶縁膜１０を介して形成する
他の一方向電極１５をもつ構造において、絶縁膜
１０を圧電板上１に形成した一方向電極１４上部
分のみを厚くして（例えば、膜厚として、5000
Å）他の一方向電極１５部分の絶縁膜を薄く（例
えば膜厚として1500Å）した構造であり、電極１
４と電極１５との絶縁度を向上させると同時に、
電極部下の絶縁膜を薄くして、圧電板との電気―
機械結合係数が低下することを防ぐことができ
る。 Next, a fourth embodiment will be explained using FIG. 10. In the structure of the embodiment shown in FIG. 10, on the piezoelectric plate 1,
In a structure having a unidirectional electrode 14 of each comb-shaped electrode of an input/output transducer and another unidirectional electrode 15 formed with an insulating film 10 interposed therebetween, the unidirectional electrode has an insulating film 10 formed on a piezoelectric plate 1. 14 Thicken only the upper part (for example, make the film thickness 5000
Å) This is a structure in which the insulating film of the other unidirectional electrode 15 portion is made thinner (for example, 1500 Å in thickness), and the electrode 1
4 and the electrode 15, and at the same time,
By thinning the insulating film under the electrode, electricity between the piezoelectric plate and
It is possible to prevent the mechanical coupling coefficient from decreasing.
本発明の第５の実施例を第１１図を用いて説明
する。まず、ガラス板１７上に、入出力トランス
デユーサの櫛形電極の一方向電極１４を形成し、
その上に絶縁膜１０（膜厚として1000〜5000Å）
を形成し、絶縁膜１０上に、櫛形電極の残りの一
方向電極を形成し、この上全体に、圧電物質１８
（例えばZnO等）を、スパツタリング法等の手段
で形成する。この構造によつても、櫛形電極の製
作歩留まりの向上が図られる。 A fifth embodiment of the present invention will be described using FIG. 11. First, the unidirectional electrode 14 of the comb-shaped electrode of the input/output transducer is formed on the glass plate 17,
On top of that is an insulating film 10 (1000 to 5000 Å thick)
The remaining unidirectional electrode of the comb-shaped electrode is formed on the insulating film 10, and a piezoelectric material 18 is formed on the entire comb-shaped electrode.
(for example, ZnO, etc.) by a sputtering method or the like. This structure also improves the manufacturing yield of the comb-shaped electrode.
次に本発明の第６の実施例を第１２図を用いて
説明するとガラス板１７上に入出力トランスデユ
ーサの櫛形電極の一方向電極１４を形成し、その
上に絶縁膜１０（膜厚―1000〜5000Å）を形成
し、その上に櫛形電極の他の一方向電極１５を形
成し、その上一面に、圧電物質１８の温度係数を
相殺する物質１９（例えば、圧電物質１８とし
て、ZnO膜を用いる場合は、絶縁物質１９とし
て、SiO2膜）を形成した後、この上に圧電物質
１８を形成する。この構造によれば、櫛形電極１
４と他の櫛形電極１５とが、電気的に短絡するこ
となく、しかも電極上に絶縁膜１９が形成されて
いるため、素子としての温度係数を小さくできる
と同時に、電極の保護膜として絶縁膜１９が作用
するため、圧電体１８の再生時に電極が影響をう
けることなく、素子としての再生が容易である。 Next, a sixth embodiment of the present invention will be described with reference to FIG. -1000 to 5000 Å), another unidirectional comb-shaped electrode 15 is formed thereon, and a material 19 that cancels the temperature coefficient of the piezoelectric material 18 (for example, ZnO If a film is used, a SiO 2 film is formed as the insulating material 19, and then the piezoelectric material 18 is formed thereon. According to this structure, the comb-shaped electrode 1
4 and the other comb-shaped electrode 15, and since the insulating film 19 is formed on the electrode, the temperature coefficient of the element can be reduced, and at the same time, the insulating film can be used as a protective film for the electrode. 19 acts, the electrodes are not affected when the piezoelectric body 18 is regenerated, and the piezoelectric body 18 can be easily regenerated as an element.
以下、本発明の第７の実施例を第１３図を用い
て説明すると、ガラス板１７上に、入出力トラン
スデユーサとなる櫛形電極の一方向電極１４を形
成し、その上に圧電体１８（例えば、ZnO膜）を
形成し、その上に、櫛形電極の他の一方向電極１
５を、ガラス板１７上に形成した電極に対し、位
相が180゜変化する位置に形成する。この構造に
よれば、圧電体１８を櫛形電極１４と櫛形電極１
５との絶縁膜に利用することができ、各電極の短
絡を防ぐことができるとともに、製作が容易であ
るという特徴を有する。 Hereinafter, a seventh embodiment of the present invention will be described with reference to FIG. 13. A unidirectional comb-shaped electrode 14 serving as an input/output transducer is formed on a glass plate 17, and a piezoelectric material 18 is disposed on the unidirectional comb-shaped electrode 14. (for example, a ZnO film), and on top of that, another unidirectional comb-shaped electrode 1
5 is formed at a position where the phase changes by 180° with respect to the electrode formed on the glass plate 17. According to this structure, the piezoelectric body 18 is connected to the comb-shaped electrode 14 and the comb-shaped electrode 1.
It can be used as an insulating film with 5, prevent short circuits between the electrodes, and is easy to manufacture.
次に第８の実施例を第１４図を用いて説明する
と、ガラス板１７上に、入出力トランスデユーサ
となる櫛形電極の一方向電極１４を形成し、その
上一面に絶縁膜２０Ａを形成し、その上に圧電体
１８を形成し、圧電体１８上全面に絶縁膜２０Ｂ
を形成し、その上に、櫛形電極の他の一方向電極
１５を形成する、この構造によれば、圧電体１８
と絶縁物２０Ａ，２０Ｂとの温度係数をそれぞれ
相殺する関係に選んでおくことによつて、素子と
しての温度係数を小さくすることができる。また
絶縁物２０Ａ，２０Ｂ及び圧電物質１８を介して
電極１４，１５が対向するため、圧電物質１８の
絶縁性が問題になることもなく、素子の性能が向
上する。 Next, the eighth embodiment will be described with reference to FIG. 14. A unidirectional comb-shaped electrode 14 that becomes an input/output transducer is formed on a glass plate 17, and an insulating film 20A is formed on the entire surface thereof. Then, a piezoelectric body 18 is formed thereon, and an insulating film 20B is formed on the entire surface of the piezoelectric body 18.
According to this structure, in which a comb-shaped electrode 15 is formed on top of the piezoelectric body 18
By selecting a relationship that cancels out the temperature coefficients of the insulators 20A and 20B, the temperature coefficient of the element can be reduced. Furthermore, since the electrodes 14 and 15 face each other via the insulators 20A and 20B and the piezoelectric material 18, the insulation properties of the piezoelectric material 18 do not become a problem, and the performance of the element is improved.
さらに本発明の第９の実施例を第１５図、及び
第１６図を用いて説明する。ここまでに説明した
本発明の実施例では入出力トランスデユーサの電
極形状は櫛形状電極の例で説明したが、本発明の
構造によれば、第１電極と第２電極とがその間に
絶縁物を介して、絶縁されているため、その相互
の電気的短絡が発生しにくく、かつ櫛形状である
必要がない。例えば第１５図に示す梯子形状でも
よく、また第１６図に示すメツシユ構造等でも良
く、この形状によれば、電極ストライプの断線不
良を軽減することができる。図において、１は圧
電体、６は絶縁膜である。 Furthermore, a ninth embodiment of the present invention will be described using FIGS. 15 and 16. In the embodiments of the present invention described so far, the electrode shape of the input/output transducer has been explained as an example of a comb-shaped electrode, but according to the structure of the present invention, the first electrode and the second electrode are insulated between them. Since they are insulated through an object, electrical short circuits between them are less likely to occur, and they do not need to be comb-shaped. For example, a ladder shape as shown in FIG. 15 or a mesh structure as shown in FIG. 16 may be used, and this shape can reduce disconnection defects in the electrode stripes. In the figure, 1 is a piezoelectric body and 6 is an insulating film.
次に本発明の第10の実施例を第１７図を用いて
説明すると、圧電体１表面に凹部を形成し、その
凹部に入出力トランスデユーサの一方向電極１４
を形成する。次に、この表面に絶縁膜１０を（膜
厚1000〜5000Å程度）形成し、絶縁膜１０上に、
入出力トランスデユーサの残り一方向電極１５を
形成する。この構造によれば、圧電体表面と、入
出力トランスデユーサの一方向電極１４とが平坦
に製作されるため、その上に形成する絶縁膜が平
坦になり、そのため、絶縁膜にクラツク、及び膜
厚の不均一な部分の発生が少なくなり、入出力ト
ランスデユーサの電極１４及び１５との絶縁性が
より高く維持されるという利点がある。この構造
において基板として圧電体を用いて説明したが、
圧電体の代りに、ガラス板を用いて上記構造を製
作し、絶縁膜１０及び、電極１５上に、圧電膜を
形成しても良い。 Next, a tenth embodiment of the present invention will be described with reference to FIG. 17. A recess is formed on the surface of the piezoelectric body 1, and a unidirectional electrode 14 of an input/output transducer is formed in the recess.
form. Next, an insulating film 10 (film thickness of about 1000 to 5000 Å) is formed on this surface, and on the insulating film 10,
The remaining unidirectional electrode 15 of the input/output transducer is formed. According to this structure, since the surface of the piezoelectric body and the unidirectional electrode 14 of the input/output transducer are manufactured flat, the insulating film formed thereon is flat, so that cracks and This has the advantage that the occurrence of non-uniform portions in film thickness is reduced, and higher insulation from the electrodes 14 and 15 of the input/output transducer is maintained. Although this structure was explained using a piezoelectric material as the substrate,
The above structure may be manufactured using a glass plate instead of a piezoelectric body, and a piezoelectric film may be formed on the insulating film 10 and the electrode 15.
以上種々の実施例をあげて説明したが、本発明
によれば入出力トランスデユーサの交互電極間に
絶縁物が介入するため、それぞれの電極間隔を有
限にする必要はなく、第１８図に示す如く、電極
間隔を０にすることも可能であり、その分素子面
積の微細化が可能になる。 Although various embodiments have been described above, according to the present invention, since an insulator intervenes between alternate electrodes of the input/output transducer, it is not necessary to make the distance between each electrode finite, and as shown in FIG. As shown, it is possible to reduce the electrode spacing to 0, and the element area can be miniaturized accordingly.
次に本発明の構造をもつ素子についてその信号
の入出力方法の一例を説明すると、第１９図に示
すように、圧電体１上に入出力トランスデユーサ
の一方向電極１４を形成し、この上全面に絶縁物
６を形成し、次に、他の一方向電極１５を形成す
るが、この時、同時に、信号取出し電極２１とし
て先に形成した一方向電極１４の信号取出し部に
相当させて形成する。この状態を第２０図に示す
が、一方向電極１４の信号取出し部と、絶縁物６
上の信号取出し部２１は、電気的容易結合とな
り、その容量を利用して、絶縁物上の信号取出し
部から、電気的信号の入出力が可能になる。 Next, an example of a signal input/output method for the element having the structure of the present invention will be explained. As shown in FIG. An insulator 6 is formed on the entire upper surface, and then another unidirectional electrode 15 is formed. At this time, at the same time, the insulator 6 is formed as a signal extraction electrode 21 corresponding to the signal extraction part of the unidirectional electrode 14 formed earlier. Form. This state is shown in FIG. 20, where the signal extraction portion of the one-way electrode 14 and the
The upper signal extraction section 21 is easily electrically coupled, and by utilizing its capacitance, it is possible to input and output electrical signals from the signal extraction section on the insulator.
以上、実施例を用いて本発明を説明したが、実
施例のなかで、入出力トランスデユーサの第１電
極及び、絶縁膜上に形成する第２電極とは、それ
ぞれ、相関をもたして説明したが、入出力トラン
スデユーサのそれぞれで、絶縁物を介して交互方
向であつても良い。 The present invention has been described above using examples. In the examples, the first electrode of the input/output transducer and the second electrode formed on the insulating film each have a correlation. However, each of the input and output transducers may be arranged in alternate directions through an insulator.
また、入出力トランスデユーサの第１及び第２
電極の絶縁膜として無機物を用いて説明したが、
例えば、ポリイミド，ポリアミドイミド膜等の有
機物絶縁膜を用いても良い。 In addition, the first and second input/output transducers
Although the explanation was made using an inorganic material as the insulating film of the electrode,
For example, an organic insulating film such as a polyimide or polyamide-imide film may be used.
また、圧電体上もしくはガラス上全面に、絶縁
膜を形成する構造で実施例を説明したが、入出力
トランスデユーサを形成する部分のみ絶縁膜を形
成しても良い。また入力電極と出力電極が絶縁物
を介して交互方向でも良い。 Furthermore, although the embodiment has been described with a structure in which an insulating film is formed over the entire surface of the piezoelectric body or glass, the insulating film may be formed only on the portion where the input/output transducer is to be formed. Further, the input electrodes and the output electrodes may be arranged in alternate directions with an insulator interposed therebetween.
以上、本発明は圧電体もしくは絶縁体上に、入
出力トランスデユーサを形成してなる弾性表面波
素子において、入出力トランスデユーサの電極を
交互に絶縁体または圧電体の少くとも一方を介し
て形成することによつて、それぞれの電極が電気
的短絡欠陥の発生することもなく、しかも、従来
のホトマスクを使用して、電極の集積度が従来の
２倍に上げられることから、高周波素子として応
用でき、また、素子としての温度係数を小さくす
ることができ、圧電体との電気―機械結合係数を
小さくすることができるため、電極数の多い素子
において不要信号を少なくすることができる等の
利点がある。 As described above, the present invention provides a surface acoustic wave device in which an input/output transducer is formed on a piezoelectric material or an insulator, in which the electrodes of the input/output transducer are alternately connected through at least one of the insulator or the piezoelectric material. By forming each electrode using a conventional photomask, electrical short circuit defects do not occur in each electrode, and the integration density of the electrodes can be doubled compared to the conventional photomask, making it suitable for high-frequency devices. In addition, the temperature coefficient of the element can be lowered, and the electrical-mechanical coupling coefficient with the piezoelectric body can be lowered, so unnecessary signals can be reduced in elements with a large number of electrodes. There are advantages.
第１図は従来の弾性表面波素子の平面図、第２
図は同断面図、第３図は本発明の第１の実施例に
おける弾性表面波素子の平面図、第４図は同断面
図、第５図イ〜チは本発明の弾性表面波素子の製
造工程を順に示す断面図、第６図は従来のマスク
パターンの断面図、第７図は本発明で使用するマ
スクパターンの断面図、第８図イ，ロは本発明の
弾性表面波素子を製作する他の方法を示す工程
図、第９図〜第１４図は本発明の他の実施例を示
す断面図、第１５図，第１６図は同平面図、第１
７図，第１８図は同断面図、第１９図は本発明に
係る弾性表面波素子の入出力取出しの一方法を示
す平面図、第２０図は同断面図である。
１……圧電体、２……入力信号、３……入力ト
ランスデユーサ、４……出力トランスデユーサ、
５Ａ，５Ｂ，７Ａ，７Ｂ……櫛形電極、６……絶
絶物、８，１１……金属膜、９，１２……ホトレ
ジスト、１０……絶縁膜、１３……絶縁膜、１
４，１５……櫛形電極、１６……絶縁膜、１７…
…ガラス板、１８……圧電体、１９……絶縁膜、
２０Ａ，２０Ｂ……絶縁物、２１……電極。
Figure 1 is a plan view of a conventional surface acoustic wave element;
3 is a plan view of the surface acoustic wave device according to the first embodiment of the present invention, FIG. 4 is a sectional view of the same, and FIGS. 6 is a sectional view of a conventional mask pattern, FIG. 7 is a sectional view of a mask pattern used in the present invention, and FIGS. FIGS. 9 to 14 are sectional views showing other embodiments of the present invention, FIGS. 15 and 16 are plan views of the same, and FIGS.
7 and 18 are sectional views of the same, FIG. 19 is a plan view showing one method of extracting input and output from the surface acoustic wave element according to the present invention, and FIG. 20 is a sectional view of the same. 1... Piezoelectric body, 2... Input signal, 3... Input transducer, 4... Output transducer,
5A, 5B, 7A, 7B... Comb-shaped electrode, 6... Insulating material, 8, 11... Metal film, 9, 12... Photoresist, 10... Insulating film, 13... Insulating film, 1
4, 15...Comb-shaped electrode, 16...Insulating film, 17...
... glass plate, 18 ... piezoelectric body, 19 ... insulating film,
20A, 20B...Insulator, 21... Electrode.
Claims (1)
れ、上記入出力電極の各々は複数の枝部を有しか
つ各枝部が隣接する枝部と互いに間隙を有して配
され共通の母線で接続された電極片の一対で構成
され、上記入出力電極の各々における一対の電極
片は基板の厚み方向に絶縁性の中間物質を介して
分離されており、かつ一方の電極片の枝部が他方
の電極片の枝部の中間位置に配されたことを特徴
とする弾性表面波素子。 ２ 基板が圧電体基板、中間物質が絶縁体膜であ
り、この絶縁体膜が上記圧電体基板とその上に形
成された入出力電極の各々の一方の電極片の全面
を覆つて形成された特許請求の範囲第１項記載の
弾性表面波素子。 ３ 電極片上を覆う絶縁体膜が他の領域を覆う絶
縁体膜より厚い特許請求の範囲第２項記載の弾性
表面波素子。 ４ 圧電体基板の表面が凹凸形状を有し、その凹
状部基板表面上に入出力電極の各々の一方の電極
片が配置され、圧電体基板と同一平面を形成した
特許請求の範囲第２項記載の弾性表面波素子。 ５ 基板が圧電体板上に第１の絶縁体膜を形成し
たものであり、中間物質が第２の絶縁体膜であ
り、第２の絶縁体膜が上記第１の絶縁体膜とその
上に形成された入出力電極の各々の一方の電極片
の全面を覆つて形成された特許請求の範囲第１項
記載の弾性表面波素子。 ６ 第１の絶縁体膜が圧電体の温度係数を補償す
る物質であり、圧電体板上面に形成された特許請
求の範囲第５項記載の弾性表面波素子。 ７ 基板がガラス基板、中間物質が絶縁性の圧電
体であり、この圧電体が上記ガラス基板とその上
に形成された入出力電極の各々の一方の電極片の
全面を覆つて形成された特許請求の範囲第１項記
載の弾性表面波素子。 ８ 基板がガラス基板、中間物質が圧電体の両面
全面を絶縁体膜で覆つた多重層である特許請求の
範囲第１項記載の弾性表面波素子。 ９ 絶縁体膜が圧電体の温度係数を補償する物質
である特許請求の範囲第８項記載の弾性表面波素
子。 １０ 電極片の形状がくし形状である特許請求の
範囲第１項乃至第５項または第７項のいずれかに
記載の弾性表面波素子。 １１ 電極片の形状が梯子状である特許請求の範
囲第１項乃至第５項または第７項のいずれかに記
載の弾性表面波素子。 １２ 電極片の形状がメツシユ状である特許請求
の範囲第１項乃至第５項または第７項のいずれか
に記載の弾性表面波素子。[Scope of Claims] 1. At least input/output electrodes are disposed on the surface of the substrate, each of the input/output electrodes having a plurality of branches, and each branch is disposed with a gap between each branch and the adjacent branch. The pair of electrode pieces in each of the above input/output electrodes are separated through an insulating intermediate material in the thickness direction of the substrate, and one electrode A surface acoustic wave element characterized in that a branch of one electrode piece is arranged at an intermediate position between the branches of the other electrode piece. 2. The substrate is a piezoelectric substrate, the intermediate material is an insulating film, and this insulating film is formed to cover the entire surface of the piezoelectric substrate and one electrode piece of each of the input/output electrodes formed thereon. A surface acoustic wave device according to claim 1. 3. The surface acoustic wave device according to claim 2, wherein the insulating film covering the electrode piece is thicker than the insulating film covering other areas. 4. Claim 2, wherein the surface of the piezoelectric substrate has an uneven shape, and one electrode piece of each of the input and output electrodes is arranged on the concave surface of the substrate to form the same plane as the piezoelectric substrate. The surface acoustic wave device described above. 5. The substrate is a piezoelectric plate with a first insulating film formed thereon, the intermediate material is a second insulating film, and the second insulating film is the first insulating film and the above-mentioned first insulating film. 2. The surface acoustic wave device according to claim 1, which is formed to cover the entire surface of one electrode piece of each of the input and output electrodes formed on the surface. 6. The surface acoustic wave device according to claim 5, wherein the first insulating film is a material that compensates for the temperature coefficient of the piezoelectric material and is formed on the top surface of the piezoelectric material plate. 7. A patent in which the substrate is a glass substrate, the intermediate material is an insulating piezoelectric material, and the piezoelectric material covers the entire surface of the glass substrate and one electrode piece of each of the input/output electrodes formed thereon. A surface acoustic wave device according to claim 1. 8. The surface acoustic wave device according to claim 1, wherein the substrate is a glass substrate, and the intermediate material is a multilayer in which both surfaces of the piezoelectric material are covered with insulating films. 9. The surface acoustic wave device according to claim 8, wherein the insulating film is a material that compensates for the temperature coefficient of the piezoelectric material. 10. The surface acoustic wave device according to any one of claims 1 to 5 or 7, wherein the electrode pieces have a comb shape. 11. The surface acoustic wave device according to any one of claims 1 to 5 or 7, wherein the electrode pieces have a ladder-like shape. 12. The surface acoustic wave device according to any one of claims 1 to 5 or 7, wherein the electrode piece has a mesh-like shape.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13488477A JPS5467792A (en) | 1977-11-09 | 1977-11-09 | Elastic surface wave element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13488477A JPS5467792A (en) | 1977-11-09 | 1977-11-09 | Elastic surface wave element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5467792A JPS5467792A (en) | 1979-05-31 |
| JPS6142891B2 true JPS6142891B2 (en) | 1986-09-24 |
Family
ID=15138749
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13488477A Granted JPS5467792A (en) | 1977-11-09 | 1977-11-09 | Elastic surface wave element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5467792A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013108608A1 (en) * | 2012-01-20 | 2013-07-25 | パナソニック株式会社 | Elastic wave sensor |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09153758A (en) * | 1995-09-29 | 1997-06-10 | Toshiba Corp | Surface acoustic wave device |
| JP2008078739A (en) * | 2006-09-19 | 2008-04-03 | Fujitsu Media Device Kk | Elastic wave device and filter |
| CN110868181A (en) * | 2019-11-29 | 2020-03-06 | 清华大学 | Thin film material surface acoustic wave device with GS layered electrode and preparation method and application thereof |
| CN111010126A (en) * | 2019-12-12 | 2020-04-14 | 无锡市好达电子有限公司 | Surface acoustic wave filter structure of layered electrode and preparation method thereof |
| CN112383288A (en) * | 2020-11-16 | 2021-02-19 | 清华大学 | Temperature-compensated packaging-free surface acoustic wave device and preparation method thereof |
-
1977
- 1977-11-09 JP JP13488477A patent/JPS5467792A/en active Granted
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013108608A1 (en) * | 2012-01-20 | 2013-07-25 | パナソニック株式会社 | Elastic wave sensor |
| US9322809B2 (en) | 2012-01-20 | 2016-04-26 | Panasonic Intellectual Property Management Co., Ltd. | Elastic wave sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5467792A (en) | 1979-05-31 |
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