JPS61136312A - Surface acoustic wave element - Google Patents

Surface acoustic wave element

Info

Publication number
JPS61136312A
JPS61136312A JP25835584A JP25835584A JPS61136312A JP S61136312 A JPS61136312 A JP S61136312A JP 25835584 A JP25835584 A JP 25835584A JP 25835584 A JP25835584 A JP 25835584A JP S61136312 A JPS61136312 A JP S61136312A
Authority
JP
Japan
Prior art keywords
insulating film
acoustic wave
surface acoustic
film
reed
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.)
Pending
Application number
JP25835584A
Other languages
Japanese (ja)
Inventor
Takehiko Sone
竹彦 曽根
Takehiro Takojima
武広 蛸島
Yoshimi Kamijo
芳省 上條
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Alps Alpine Co Ltd
Original Assignee
Alps Electric Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Alps Electric Co Ltd filed Critical Alps Electric Co Ltd
Priority to JP25835584A priority Critical patent/JPS61136312A/en
Publication of JPS61136312A publication Critical patent/JPS61136312A/en
Pending legal-status Critical Current

Links

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
    • H03H9/02614—Treatment of substrates, e.g. curved, spherical, cylindrical substrates ensuring closed round-about circuits for the acoustical waves
    • H03H9/02622—Treatment of substrates, e.g. curved, spherical, cylindrical substrates ensuring closed round-about circuits for the acoustical waves of the surface, including back surface

Landscapes

  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)

Abstract

PURPOSE:To prevent a short circuit phenomenon between electrodes of a reed- screen-shaped electrode sufficiently even by a comparatively thin insulating film, and also to reduce a resonance resistance increase rate in a high frequency by covering the reed-screen-shaped electrode part with an insulating film whose surface is flat. CONSTITUTION:A metallic film of Al or an Al alloy, etc. is formed on a piezoelectric substrate 1, a reed-screen-shaped electrode 2 is formed by etching said film, and thereafter, covered with an insulating film 5 so as to fill up a step difference of the reed-screen-shaped electrode 2 by means of a bias sputtering method, etc., and the surface of the insulating film 5 is flattened. In this case, it is desirable that an oxide such as SiOx, AlOx, etc., a nitride such as SiNx, TaNx, etc., or an inorganic insulating film consisting of their composite body is used as the insulating film 5. Also, a thickness of the film is set to 500Angstrom -3,000Angstrom . In case of <500Angstrom , a preventing effect of a short circuit phenomenon between the electrodes is not obtained enough, and in case of exceeding 3,000 deg., a resonance resistance increases.

Description

【発明の詳細な説明】 「技術分野」 本発明は遅延線１発振器、フ、イルタなどに適用される
弾性表面波素子に関する。DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a surface acoustic wave element applied to a delay line 1 oscillator, filter, filter, etc.

「従来技術およびその問題点」 弾性表面波素子は、従来軍需用の特殊な用途に使用され
ていたが、近年ＦＭチューナ、ＴＶ等の民生用機器にも
使用され始め、にわかに脚光を浴びるようになってきた
。Ｉｊｌ性表面表面波素子体的には遅延素子１発振子、
フィルタなどとして製品化されている。これら各種の弾
性表面波素子の特徴は、小型、軽量で、信頼性が高いこ
と、およびその製造工程が集積回路と類似しており、量
産性に富むことなどである。そして、現在では欠くべか
らざる電子部品として量産されるに至っている。"Prior art and its problems" Surface acoustic wave elements have traditionally been used for special military purposes, but in recent years they have begun to be used in consumer equipment such as FM tuners and TVs, and have suddenly come into the spotlight. It has become. Ijl type surface wave element Physically, a delay element 1 oscillator,
It has been commercialized as a filter, etc. The characteristics of these various surface acoustic wave devices are that they are small, lightweight, and highly reliable, and that their manufacturing process is similar to that of integrated circuits, making them highly suitable for mass production. Nowadays, it is mass-produced as an indispensable electronic component.

従来の弾性表面波素子の一例を弾性表面波共振子を例と
して説明すると、第５図および第６図に示すように、圧
電基板１の上に導電性物質からなるすだれ状電極２が形
成されている。この場合、圧電基板１は１例えば水晶、
ニオブ酸リチウムなどの圧・電性をもった単結晶や圧電
セラミックス、あるいはガラスの表面に圧電性をもった
薄膜を形成したものが使用される。また、すだれ状電極
２は、例えばアルミニウム、金などの金属を圧電基板１
の上に蒸着後、フォトエツチングにより形成することが
できる。そして、このすだれ状電極２の両側に誘電体、
導電体、溝等からなるリッジで構成される１対の格子状
反射器３．３が形成されている。To explain an example of a conventional surface acoustic wave element using a surface acoustic wave resonator as an example, as shown in FIGS. 5 and 6, an interdigital electrode 2 made of a conductive material is formed on a piezoelectric substrate 1. ing. In this case, the piezoelectric substrate 1 is made of crystal, for example, crystal,
Piezoelectric single crystals such as lithium niobate, piezoelectric ceramics, or glass with a piezoelectric thin film formed on the surface are used. Further, the interdigital electrode 2 is made of a metal such as aluminum or gold on the piezoelectric substrate 1.
It can be formed by photo-etching after vapor deposition. A dielectric material is placed on both sides of this interdigital electrode 2.
A pair of lattice-like reflectors 3.3 are formed which are composed of ridges made of conductors, grooves, etc.

すだれ状電極２に特定周波数の電圧を印加すると、すだ
れ状電極２の間隙の圧電基板１表面に電界がかかり、圧
電基板ｌの圧電性により電圧に比例したひずみが生じ、
そのひずみが圧電基板１の材料によって定まった音速で
表面波として両側に伝搬する。この表面波は、両側の格
子状反射器３．３によって反射され、再びすだれ状電極
２に帰還して共振がなされるようになっている。When a voltage of a specific frequency is applied to the interdigital electrodes 2, an electric field is applied to the surface of the piezoelectric substrate 1 in the gap between the interdigital electrodes 2, and a strain proportional to the voltage is generated due to the piezoelectricity of the piezoelectric substrate l.
The strain propagates to both sides as a surface wave at a sound speed determined by the material of the piezoelectric substrate 1. This surface wave is reflected by the grating reflectors 3.3 on both sides, returns to the interdigital electrode 2 again, and resonates.

ところで、これら各種の骨性表面波素子は、第７図に示
すようなハーメチックシール４と呼ばれる金属製容器に
よって封止されるのが一般的である。ハーメチックシー
ル４は封止性、耐触性等を考慮して、通常はニッケルメ
ッキ等のメッキが施されている。Incidentally, these various bone surface wave elements are generally sealed with a metal container called a hermetic seal 4 as shown in FIG. The hermetic seal 4 is usually plated with nickel or the like in consideration of sealing properties, contact resistance, etc.

しかしながら、かかる従来の弾性表面波素子においては
、ハーメチックシール４の封止前に混入した導電性異物
や、ハーメチックシール等のメッキ剥離物等がすだれ状
電極に付着し、電極間短絡現象を起すことがあった。こ
のため、電気的インピーダンスが変化するなどの支障が
生じ、弾性表面波素子の信頼性が低下し、量産を妨げて
いた。However, in such conventional surface acoustic wave elements, conductive foreign matter mixed in before the hermetic seal 4 is sealed, peeled off plating of the hermetic seal, etc. adhere to the interdigital electrodes, causing a short circuit phenomenon between the electrodes. was there. This causes problems such as changes in electrical impedance, lowers the reliability of the surface acoustic wave element, and hinders mass production.

そこで、本発明者らは、すだれ状電極部分に絶縁膜を被
覆することにより、ハーメチックシールのメッキ剥離物
やその他の導電性異物による電極間短絡現象を防止でき
ることを見出し、既に特許出願した。Therefore, the present inventors have discovered that by covering the interdigital electrode portion with an insulating film, it is possible to prevent short-circuiting between the electrodes due to peeled off plating of the hermetic seal or other conductive foreign matter, and have already filed a patent application.

第８図にはかかる弾性表面波素子の一例が示されている
。すなわち、水晶基板等の圧電基板１の上にＡ１等の金
−属を例えばスパッタ蒸着により成膜した後、通常の湿
式エツチング法により、すだれ状電極２および反射器３
を形成する。この場合、金属の膜厚は１例えば９０ＭＨ
ｚ帯の弾性表面波素子では１ル層程度とされ、８００　
）ｌＨｚ帯の弾性表面波素子では０．１５ル■程度とさ
れる。また、エツチング液とじては例えばリン酸、硝酸
の混合液を用いる。そして、すだれ状電極２の上に二酸
化シリコン等の絶縁膜５を例えばスパッタ蒸着により成
膜する。成膜は、例えば基板温度２００℃、成膜レート
Ｑ、１５　ｐ−ｉ／ｈｒ、　Ａｒ−１−０２混合ガス圧
３　Ｘ　１Ｏ−３Ｔｏｒｒにて基板１を自公転しながら
行なう。FIG. 8 shows an example of such a surface acoustic wave element. That is, after forming a film of a metal such as A1 by sputter deposition on a piezoelectric substrate 1 such as a quartz substrate, the interdigital electrodes 2 and the reflector 3 are formed by a normal wet etching method.
form. In this case, the metal film thickness is 1, for example, 90MH
Z-band surface acoustic wave devices are said to have about 1 layer, and 800
) For surface acoustic wave devices in the 1Hz band, it is approximately 0.15 l. Further, as the etching solution, for example, a mixed solution of phosphoric acid and nitric acid is used. Then, an insulating film 5 made of silicon dioxide or the like is formed on the interdigital electrode 2 by, for example, sputter deposition. The film formation is performed, for example, at a substrate temperature of 200° C., a film formation rate Q of 15 pi/hr, and an Ar-1-02 mixed gas pressure of 3×10-3 Torr while rotating the substrate 1.

しかしながら、この弾性表面波素子では、電極間短絡現
象を効果的に防止するため、絶縁ｊ１５の膜厚を２００
０人程度以上とすることが必要となり、それによって弾
性表面波素子の共振抵抗が増大するという問題点が生じ
る０例えば９Ｇ＞ｌＨｚ帯の弾性表面波素子では絶縁膜
５の膜厚が２０００人のとき、共振抵抗増加率は最大１
０％程度であり、設計上対応できる程度なのでそれほど
問題はない、しかし、例えば８００ＭＩ（ｚ帯の弾性表
面波素子では絶縁膜５の膜厚が２０００人のとき、共振
抵抗増加率が平均でも１５％、最大では２５％になり、
バラツキも増大して生産性が低下することがわかった。However, in this surface acoustic wave element, in order to effectively prevent the phenomenon of short circuit between electrodes, the thickness of the insulation j15 is set to 200 mm.
For example, in a surface acoustic wave element in the 9G>lHz band, the film thickness of the insulating film 5 is approximately 2,000 people. When, the resonant resistance increase rate is up to 1
This is about 0%, which can be accommodated in the design, so it is not a big problem. However, for example, in a Z-band surface acoustic wave element, when the thickness of the insulating film 5 is 2000, the resonant resistance increase rate is 15% on average. %, maximum is 25%,
It was found that variation also increased and productivity decreased.

したがって、この弾性表面波素子は、例えばＶＨＦ帯に
おいては充分に実用化できるが、さらに高周波の例えｔ
ｆＵＨＦ帯では共振抵抗の増加を無視できなくなる。Therefore, this surface acoustic wave element can be fully put to practical use in the VHF band, for example, but it can also be put to practical use in the VHF band.
In the fUHF band, the increase in resonance resistance cannot be ignored.

「発明の目的」 本発明の目的は、ハーメチックシールのメッキ剥離物や
その他の導電性異物による電極間短絡現象を防止でき、
かつ、高周波の場合にも共振抵抗の増加を低く抑えるこ
とができるようにした弾性表面波素子を提供することに
ある。"Objective of the Invention" The object of the present invention is to prevent short-circuiting between electrodes caused by peeled off plating of hermetic seals or other conductive foreign matter;
Another object of the present invention is to provide a surface acoustic wave element that can suppress an increase in resonance resistance even in the case of high frequencies.

「発明の構成」 本発明による弾性表面波素子は、すだれ状電極部分に絶
縁膜が被覆され、この絶縁膜の表面が平坦化されている 本発明は、第８図に示した弾性表面波素子の問題点につ
いて検討し、これをさらに改良したものである。すなわ
ち、第８図に示した弾性表面波素子では、第９図に示す
ように、すだれ状電極２がエツチングにより圧電基板１
から突出した状態となるので、これに絶！＆膜５をスパ
ッタ蒸着などの゛　通常の方法で被覆したとき、絶縁膜
５は実際には図示の如く凹凸状態となる。このため、例
えば図中Ａで示す部分においては、絶縁Ｍ５の膜厚が薄
くなり、さらにパターンサイド面の平滑性の影響をうけ
、電極間短絡現象の防止効果が弱められるのである。``Structure of the Invention'' The surface acoustic wave device according to the present invention has an insulating film coated on the interdigital electrode portion, and the surface of the insulating film is flattened. This study investigated the problems of , and further improved it. That is, in the surface acoustic wave element shown in FIG. 8, the interdigital electrode 2 is etched onto the piezoelectric substrate 1 as shown in FIG.
It will be in a state of protrusion, so this is absolutely perfect! When the & film 5 is coated by a normal method such as sputter deposition, the insulating film 5 actually becomes uneven as shown in the figure. For this reason, for example, in the portion indicated by A in the figure, the film thickness of the insulator M5 becomes thinner, and is further affected by the smoothness of the side surface of the pattern, weakening the effect of preventing short-circuiting between the electrodes.

本発明による弾性表面波素子は、例えば第１図および第
２図に示されるように、圧電基板１上にＡ１もしくはＡ
１合金などの金属膜を形成し、これをエツチングしてす
だれ状電極２を形成した後、バイアススパッタリング法
などの方法で、すだれ状電極２の段差を埋めるように絶
縁ＩＦＪ５を被覆し。The surface acoustic wave element according to the present invention is provided with A1 or A1 on a piezoelectric substrate 1, as shown in FIGS. 1 and 2, for example.
After forming a metal film such as No. 1 alloy and etching it to form the interdigital electrode 2, the insulating IFJ 5 is coated using a method such as bias sputtering so as to fill the steps of the interdigital electrode 2.

絶縁膜５の表面を平坦にしである。このため、絶縁膜５
による絶縁効果がより確実となり、すだれ状電極２上の
絶縁膜５の厚さｗｅ薄くしても充分な絶縁性が得られる
ようになり、絶縁膜５の膜厚を薄くして共振抵抗の増加
を小さく抑えることができる。したがって、本発明の弾
性表面波素子によれば、ＵＨＦＨＦ上の高周波の場合に
も共振抵抗をそれほど増大させることがない。The surface of the insulating film 5 is made flat. Therefore, the insulating film 5
The insulation effect is more reliable, and even if the thickness of the insulation film 5 on the interdigital electrode 2 is made thinner, sufficient insulation can be obtained. can be kept small. Therefore, according to the surface acoustic wave element of the present invention, the resonance resistance does not increase significantly even in the case of high frequencies such as UHFHF.

本発明の好ましい態様によれば、絶縁膜５としては、Ｓ
ｉＯｘ、　ＴａＯｘ、ＡｌＯｘ等の酸化物、ＳｉＮｘ、
　ＴａＮｘ等の窒化物、あるいはそれらの複合体からな
る無機絶縁膜が使用される。According to a preferred embodiment of the present invention, the insulating film 5 includes S
Oxides such as iOx, TaOx, AlOx, SiNx,
An inorganic insulating film made of nitride such as TaNx or a composite thereof is used.

本発明のさらに好ましい態様によれば、絶縁膜５は膜厚
が５００〜３０００人とされる。絶縁ｌｌ１５の膜厚が
５００人未満では電極間短絡現象の防止効果が充分に得
られにくくなり、３０００人を超えると共振抵抗が増大
する傾向となる。According to a further preferred embodiment of the present invention, the insulating film 5 has a thickness of 500 to 3000 layers. If the film thickness of the insulator 115 is less than 500 people, it will be difficult to sufficiently prevent the phenomenon of short circuit between electrodes, and if it exceeds 3000 people, the resonance resistance will tend to increase.

「発明の実施例」 実施例 鏡面研磨を施した水晶基板を圧電基板１とし、その上に
ＡＩを膜厚２０００人となるようにスパッタ蒸着した。"Embodiments of the Invention" Example A mirror-polished quartz crystal substrate was used as the piezoelectric substrate 1, and AI was sputter-deposited thereon to a thickness of 2000 nm.

次いで、すだれ状電極部２および反射器３を通常の湿式
フォトエツチング法により形成した。さらにその上に、
二酸化シリコンを基板加熱温度２００℃、成膜レート０
．５　ｕ、ｍ／ｈｒ、　Ａｒガス圧３　Ｘ　１Ｇ−３Ｔ
ｏｒｒ、バイアス電圧−３００ｖにてバイアススパッタ
蒸着した。そして、すだれ状電極部２以外の二酸化シリ
コンを除去し、絶縁膜５を形成した。こうして、第１図
および第２図に示すような構造を有する弾性表面波素子
を製造した。Next, the interdigital electrode section 2 and the reflector 3 were formed by a conventional wet photoetching method. Furthermore, on top of that
Silicon dioxide is heated to a substrate temperature of 200°C and a film formation rate of 0.
．． 5 u, m/hr, Ar gas pressure 3 x 1G-3T
orr, bias sputter deposition was performed at a bias voltage of -300V. Then, silicon dioxide other than the interdigital electrode portions 2 was removed, and an insulating film 5 was formed. In this way, a surface acoustic wave device having a structure as shown in FIGS. 1 and 2 was manufactured.

次に、この弾性表面波素子の電極間短絡現象の防止効果
を試験するため、第５図に示すように、マスク蒸着法に
より絶縁ｌｌｌ５の上にＡ１を２０００人の厚さでスパ
ッタ蒸着し、擬似導電性異物８を形成した。擬似導電性
異物８は、上方から見てすだれ状電極２にまたがる大き
さとされ、すだれ状電極２を被覆する絶縁膜５の上の任
意の場所に数個付着させた。そして、この擬似導電性異
物８を形成した後、直流抵抗不良率を測定して、すだれ
状電極２の電極間短絡現象を検討した。なお、この試験
方法は、従来より用いられている振動試験によるものと
比較して、少ない数量でより確実かつ厳密に検査できる
方法であることが実験より分っている。Next, in order to test the effect of preventing the short-circuit phenomenon between the electrodes of this surface acoustic wave element, as shown in FIG. A pseudo-conductive foreign material 8 was formed. The pseudo-conductive foreign matter 8 was sized to span the interdigital electrode 2 when viewed from above, and several pieces were attached to arbitrary locations on the insulating film 5 covering the interdigital electrode 2 . After forming the pseudo-conductive foreign matter 8, the direct current resistance failure rate was measured to examine the short-circuit phenomenon between the interelectrode of the interdigital electrode 2. It has been found through experiments that this test method allows for more reliable and rigorous testing with a smaller number of products than the conventionally used vibration test.

そして、第１図および第２ｒｙＪに示す弾性表面波素子
を、二酸化シリコンからなる絶縁膜５の膜厚を５００人
、１０００人、２０００人、　３０００人と変えて製造
し、それぞれについて上述した方法により直流抵抗不良
率を測定すると共に、共振抵抗増加率を測定した。その
結果を第４図に示す、なお、この弾性表面波素子ば、８
００ＭＨｚ帯のものである。第４図から、この弾性表面
波素子は、絶縁膜５の膜厚が１０００人で擬似導電性異
物８によ〜る直流抵抗不良率が零になり、その時点にお
ける共振抵抗増加率も平均で５％、最大で１０％である
ことがわかる。Then, the surface acoustic wave elements shown in FIGS. 1 and 2ryJ were manufactured by changing the thickness of the insulating film 5 made of silicon dioxide by 500, 1000, 2000, and 3000, and using the method described above for each. In addition to measuring the direct current resistance defective rate, the resonance resistance increase rate was also measured. The results are shown in FIG. 4, and this surface acoustic wave element is 8
00MHz band. From FIG. 4, it can be seen that in this surface acoustic wave element, when the thickness of the insulating film 5 is 1000, the DC resistance failure rate due to the pseudo-conductive foreign matter 8 becomes zero, and the resonant resistance increase rate at that point is also on average. It can be seen that it is 5%, and the maximum is 10%.

なお、絶縁膜５の材質をＴａＮｘ、　Ａｌ０Ｋ、ＳｉＮ
ｘ。Note that the material of the insulating film 5 is TaNx, Al0K, SiN.
x.

ＴａＮｘに変えて行なっても同様な結果が得られた。Similar results were obtained even when TaNx was used instead.

比較例 水晶基板からなる圧電基板ｌの上にＡＩをスパッタ蒸着
した後、通常の湿式エツチング法により、すだれ状電極
２および反射器３を形成した。この場合、ＡＩの膜厚は
、！３０ＭＨｚ帯の弾性表面波素子では１００００人、
　８０ＯＮ）Ｉｚ帯の弾性表面波素子では２０００人の
厚さとした。また、エツチング液はリン酸、硝酸の混合
液を用いた０次に、二酸化シリコンを基板温度２００℃
、成膜レート０．１５ｐｍ／ｈｒ、　Ａｒ＋　０２混合
ガスで全圧３　Ｘ　１０＝　Ｔｏｒｒにて基板１を自公
転しながらスパッタ蒸着した。そして、すだれ状電極２
以外の部分の二酸化シリコンを除去し、絶縁膜５を形成
した。こうして、第８面および第８図に示す弾性表面波
素子を製造した。この弾性表面波素子を、二酸化シリコ
ンからなる絶縁膜５の膜厚を１０００人、２０００人、
３０００人と変えて製造し、それぞれについて上述した
方法により直流抵抗不良率および共振抵抗増加率を測定
した。その結果を第１０図および第１１図に示す、第１
０図は９０ＭＨｚ帯の弾性表面波素子（Ａｌ膜厚１００
００人）の場合であり、第１１図は８００ＭＨｚ帯の弾
性表面波素子（Ａｔ　１１４２０００人）の場合である
。第１０図に示すように、３０ＭＨｚ帯では、絶縁＠５
の膜厚が２０００人で導電性異物８による直流抵抗不良
率が零になり、その時点の共振抵抗増加率は最大でも１
０％程度であるから充分に実用的である。しかしながら
、第１１図に示すように、８００ＭＨｚ帯では、絶縁１
ｌ１５ノ膜厚が２０００人のとき、共振抵抗増加率が最
大２５％程度と大きくなり、かつ、バラツキも増大して
生産性が悪くなることがわかる。Comparative Example After sputter-depositing AI on a piezoelectric substrate 1 made of a quartz substrate, interdigital electrodes 2 and reflectors 3 were formed by a conventional wet etching method. In this case, the thickness of AI is ! 10,000 people for 30MHz band surface acoustic wave devices,
For surface acoustic wave elements in the Iz band (80 ON), the thickness was set to 2000 mm. In addition, the etching solution used was a mixed solution of phosphoric acid and nitric acid, and silicon dioxide was etched at a substrate temperature of 200°C.
Sputter deposition was carried out at a film formation rate of 0.15 pm/hr, with an Ar+02 mixed gas at a total pressure of 3×10 Torr, while the substrate 1 was rotating around its axis. Then, the interdigital electrode 2
The silicon dioxide in the other parts was removed to form an insulating film 5. In this way, a surface acoustic wave device shown in the eighth surface and FIG. 8 was manufactured. This surface acoustic wave element was manufactured by changing the thickness of the insulating film 5 made of silicon dioxide to 1,000, 2,000,
A total of 3,000 people were used to manufacture the products, and the DC resistance failure rate and resonance resistance increase rate were measured for each product using the method described above. The results are shown in Figures 10 and 11.
Figure 0 shows a 90 MHz band surface acoustic wave device (Al film thickness 100
00 people), and FIG. 11 shows the case of an 800 MHz band surface acoustic wave element (At 1,142,000 people). As shown in Figure 10, in the 30MHz band, insulation@5
When the film thickness of
Since it is about 0%, it is sufficiently practical. However, as shown in Figure 11, in the 800MHz band, the insulation
It can be seen that when the film thickness of 115 is 2000, the resonance resistance increase rate becomes as large as about 25% at maximum, and the variation also increases, resulting in poor productivity.

「発明の効果」 以上説明したように、本発明によれば、すだれ状電極部
分に絶縁膜が被覆され、この絶縁膜の表面が平坦化され
ているので、比較的薄い絶縁膜によっても充分にすだれ
状電極の電極間短絡現象を防止でき、絶縁膜を薄くする
ことによって高周波においても共振抵抗増加率を極めて
小さくすることができる。また、上記のようにすだれ状
電極の電極間短絡現象を防止することにより、弾性表面
波素子の信頼性を飛躍的に高めることができ、量産に際
しても不良品の発生を極めて少なくすると共に、製造に
際しては検査等の作業を簡略化することができる。"Effects of the Invention" As explained above, according to the present invention, the interdigital electrode portion is coated with an insulating film, and the surface of this insulating film is flattened, so that even a relatively thin insulating film can be used. It is possible to prevent short-circuiting between the interelectrodes of the interdigital electrodes, and by making the insulating film thinner, the rate of increase in resonance resistance can be made extremely small even at high frequencies. In addition, by preventing the short-circuit phenomenon between the interelectrode of the interdigital electrodes as described above, the reliability of the surface acoustic wave device can be dramatically increased, and the occurrence of defective products can be extremely reduced during mass production. In such cases, the work such as inspection can be simplified.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明による弾性表面波素子の一実施例を示す
断面図、第２図は同弾性表面波素子の部分拡大断面図、
第３図は電極間短絡現象を調べるための試験方法を示す
平面図、第４図は本発明による弾性表面波素子の直流抵
抗不良率および共振抵抗増加率を示す図表、第５図は従
来の弾性表面波素子の一例を示す平面図、第６図は同弾
性表面波素子の断面図、第７図は弾性表面波素子をバー
メチ７クシールで封止した製品形態を示す斜視図、第８
図は本発明外の弾性表面波素子の一例を示す断面図、第
８図は同弾性表面波素子の部分拡大断面図、第１０図は
同弾性表面波素子の９０ＭＨｚにおける直流抵抗不良率
および共振抵抗増加率を示す図表、第１１図は同弾性表
面波素子の８００ＭＨｚにおける直流抵抗不良率および
共振抵抗増加率を示す図表である。 図中、１は圧電基板、２はすだれ状電極、３は反射器、
５は絶縁膜である。 区 ω 憾 ＼ｔFIG. 1 is a sectional view showing an embodiment of a surface acoustic wave device according to the present invention, FIG. 2 is a partially enlarged sectional view of the same surface acoustic wave device,
Fig. 3 is a plan view showing a test method for investigating the short-circuit phenomenon between electrodes, Fig. 4 is a chart showing the direct current resistance failure rate and resonant resistance increase rate of the surface acoustic wave device according to the present invention, and Fig. FIG. 6 is a plan view showing an example of a surface acoustic wave device, FIG. 6 is a cross-sectional view of the same surface acoustic wave device, FIG. 7 is a perspective view showing a product form in which the surface acoustic wave device is sealed with a barmetal seal, and FIG.
The figure is a cross-sectional view showing an example of a surface acoustic wave device other than the present invention, FIG. 8 is a partially enlarged cross-sectional view of the same surface acoustic wave device, and FIG. 10 is a DC resistance failure rate and resonance of the same surface acoustic wave device at 90 MHz. FIG. 11 is a chart showing the rate of increase in resistance of the same surface acoustic wave element at 800 MHz. In the figure, 1 is a piezoelectric substrate, 2 is an interdigital electrode, 3 is a reflector,
5 is an insulating film. wardω 憾＼t

Claims (3)

【特許請求の範囲】[Claims] （１）圧電基板上にすだれ状電極を形成した弾性表面波
素子において、前記すだれ状電極部分に絶縁膜が被覆さ
れ、この絶縁膜の表面が平坦化されていることを特徴と
する弾性表面波素子。(1) A surface acoustic wave device in which interdigital electrodes are formed on a piezoelectric substrate, characterized in that the interdigital electrode portions are covered with an insulating film, and the surface of the insulating film is flattened. element. （２）特許請求の範囲第１項において、前記絶縁膜はＳ
ｉＯ＿ｘ、ＴａＯ＿ｘ、ＡｌＯ＿ｘ、ＳｉＮ＿ｘ、Ｔａ
Ｎ＿ｘからなる群より選ばれた一種または二種以上の複
合体である弾性表面波素子。(2) In claim 1, the insulating film is S
iO_x, TaO_x, AlO_x, SiN_x, Ta
A surface acoustic wave element that is a composite of one or more selected from the group consisting of N_x. （３）特許請求の範囲第１項または第２項において、前
記絶縁膜は膜厚が５００〜３０００Åである弾性表面波
素子。(3) A surface acoustic wave device according to claim 1 or 2, wherein the insulating film has a thickness of 500 to 3000 Å.
JP25835584A 1984-12-06 1984-12-06 Surface acoustic wave element Pending JPS61136312A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP25835584A JPS61136312A (en) 1984-12-06 1984-12-06 Surface acoustic wave element

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP25835584A JPS61136312A (en) 1984-12-06 1984-12-06 Surface acoustic wave element

Publications (1)

Publication Number Publication Date
JPS61136312A true JPS61136312A (en) 1986-06-24

Family

ID=17319077

Family Applications (1)

Application Number Title Priority Date Filing Date
JP25835584A Pending JPS61136312A (en) 1984-12-06 1984-12-06 Surface acoustic wave element

Country Status (1)

Country Link
JP (1) JPS61136312A (en)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004059837A1 (en) * 2002-12-25 2004-07-15 Matsushita Electric Industrial Co., Ltd. Electronic component and electronic apparatus using this electronic component
US6836196B2 (en) 2001-12-28 2004-12-28 Murata Manufacturing Co., Ltd. Surface acoustic wave apparatus utilizing a leaky surface acoustic wave
EP1544998A2 (en) * 2003-12-15 2005-06-22 Alps Electric Co., Ltd. Surface acoustic wave device and manufacturing method thereof
US6914498B2 (en) 2002-01-18 2005-07-05 Murata Manufacturing Co., Ltd. Surface acoustic wave device on LiTaO3 substrate using primarily silver electrodes covered with SiO2 film
US7034433B2 (en) 2001-10-12 2006-04-25 Murata Manufacturing Co., Ltd. Surface acoustic wave device
US7230365B2 (en) 2002-07-24 2007-06-12 Murata Manufacturing Co., Ltd. Surface acoustic wave apparatus and manufacturing method therefor
US7327071B2 (en) 2004-03-02 2008-02-05 Murata Manufacturing Co., Ltd. Surface acoustic wave device
US7339304B2 (en) 2003-10-03 2008-03-04 Murata Manufacturing Co., Ltd. Surface acoustic wave device
US7528685B2 (en) 2005-05-11 2009-05-05 Seiko Epson Corporation Lamb wave type high frequency device
US7626314B2 (en) * 2006-12-27 2009-12-01 Murata Manufacturing Co., Ltd. Surface acoustic wave device

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS54132188A (en) * 1978-04-06 1979-10-13 Nippon Telegr & Teleph Corp <Ntt> Elastic surface wave device

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS54132188A (en) * 1978-04-06 1979-10-13 Nippon Telegr & Teleph Corp <Ntt> Elastic surface wave device

Cited By (21)

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Publication number Priority date Publication date Assignee Title
US7208860B2 (en) 2001-10-12 2007-04-24 Murata Manufacturing Co., Ltd. Surface acoustic wave device
US7730596B2 (en) 2001-10-12 2010-06-08 Murata Manufacturing Co., Ltd. Method for manufacturing a surface acoustic wave device
US7034433B2 (en) 2001-10-12 2006-04-25 Murata Manufacturing Co., Ltd. Surface acoustic wave device
US6836196B2 (en) 2001-12-28 2004-12-28 Murata Manufacturing Co., Ltd. Surface acoustic wave apparatus utilizing a leaky surface acoustic wave
US6914498B2 (en) 2002-01-18 2005-07-05 Murata Manufacturing Co., Ltd. Surface acoustic wave device on LiTaO3 substrate using primarily silver electrodes covered with SiO2 film
EP2288024A1 (en) 2002-07-24 2011-02-23 Murata Manufacturing Co., Ltd. Surface acoustic wave apparatus and manufacturing method therefor
US7230365B2 (en) 2002-07-24 2007-06-12 Murata Manufacturing Co., Ltd. Surface acoustic wave apparatus and manufacturing method therefor
EP2288026A1 (en) 2002-07-24 2011-02-23 Murata Manufacturing Co., Ltd. Surface acoustic wave apparatus and manufacturing method therefor
US7411334B2 (en) 2002-07-24 2008-08-12 Murata Manufacturing Co., Ltd. Surface acoustic wave apparatus and manufacturing method therefor
US7418772B2 (en) 2002-07-24 2008-09-02 Murata Manufacturing Co., Ltd. Method for manufacturing a surface acoustic wave
EP2288025A1 (en) 2002-07-24 2011-02-23 Murata Manufacturing Co., Ltd. Surface acoustic wave apparatus and manufacturing method therefor
WO2004059837A1 (en) * 2002-12-25 2004-07-15 Matsushita Electric Industrial Co., Ltd. Electronic component and electronic apparatus using this electronic component
US7538636B2 (en) 2002-12-25 2009-05-26 Panasonic Corporation Electronic part with a comb electrode and protective film and electronic equipment including same
US7855619B2 (en) 2002-12-25 2010-12-21 Panasonic Corporation Electronic part and electronic equipment with electronic part
US7339304B2 (en) 2003-10-03 2008-03-04 Murata Manufacturing Co., Ltd. Surface acoustic wave device
DE112004001841B4 (en) * 2003-10-03 2009-03-12 Murata Mfg. Co., Ltd., Nagaokakyo-shi Surface acoustic wave device
EP1544998A3 (en) * 2003-12-15 2006-08-16 Alps Electric Co., Ltd. Surface acoustic wave device and manufacturing method thereof
EP1544998A2 (en) * 2003-12-15 2005-06-22 Alps Electric Co., Ltd. Surface acoustic wave device and manufacturing method thereof
US7327071B2 (en) 2004-03-02 2008-02-05 Murata Manufacturing Co., Ltd. Surface acoustic wave device
US7528685B2 (en) 2005-05-11 2009-05-05 Seiko Epson Corporation Lamb wave type high frequency device
US7626314B2 (en) * 2006-12-27 2009-12-01 Murata Manufacturing Co., Ltd. Surface acoustic wave device

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