JPS6310909A - Frequency adjusting method for surface acoustic wave resonator - Google Patents
Frequency adjusting method for surface acoustic wave resonatorInfo
- Publication number
- JPS6310909A JPS6310909A JP15543186A JP15543186A JPS6310909A JP S6310909 A JPS6310909 A JP S6310909A JP 15543186 A JP15543186 A JP 15543186A JP 15543186 A JP15543186 A JP 15543186A JP S6310909 A JPS6310909 A JP S6310909A
- Authority
- JP
- Japan
- Prior art keywords
- center frequency
- surface acoustic
- acoustic wave
- wave resonator
- oxide film
- 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
Links
- 238000010897 surface acoustic wave method Methods 0.000 title claims abstract description 31
- 238000000034 method Methods 0.000 title claims abstract description 17
- 239000000758 substrate Substances 0.000 claims abstract description 19
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 5
- 239000001301 oxygen Substances 0.000 abstract description 5
- 229910052760 oxygen Inorganic materials 0.000 abstract description 5
- 238000004519 manufacturing process Methods 0.000 abstract description 3
- 238000004806 packaging method and process Methods 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 5
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 238000005530 etching Methods 0.000 description 3
- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 description 2
- 239000010453 quartz Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 229910003327 LiNbO3 Inorganic materials 0.000 description 1
- GWHVLKCXIHCCOA-UHFFFAOYSA-N [Cl].O=C=O Chemical compound [Cl].O=C=O GWHVLKCXIHCCOA-UHFFFAOYSA-N 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001312 dry etching Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- TXEYQDLBPFQVAA-UHFFFAOYSA-N tetrafluoromethane Chemical compound FC(F)(F)F TXEYQDLBPFQVAA-UHFFFAOYSA-N 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Landscapes
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、圧電基板上にすだれ状電極が少なくとも設け
られている弾性表面波共振子の中心周波数を調整する方
法に関する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for adjusting the center frequency of a surface acoustic wave resonator in which at least interdigital electrodes are provided on a piezoelectric substrate.
（従来の技術とその問題点）
最近では、ＩＣ製造技術により圧電基板上にすだれ状電
極、例えば、インターデジタルトランスジューサ（以下
、ＩＤＴと略記する）電極や反射器を設けた構造の弾性
表面波共振子が多用されている。(Prior art and its problems) Recently, with IC manufacturing technology, surface acoustic wave resonance of a structure in which interdigital transducer (hereinafter abbreviated as IDT) electrodes and reflectors are provided on a piezoelectric substrate has been developed. Children are often used.
ところで、この種の弾性表面波共振子においては、圧電
基板での弾性波の伝搬速度（単結晶基板においてはカッ
ト面の軸方位精度）、ＩＤＴ電極や反射器の膜厚、更に
はＩＤＴ電極の幅のばらつき等により、中心周波数が変
動してしまうことがある。By the way, in this type of surface acoustic wave resonator, the propagation speed of the elastic wave in the piezoelectric substrate (the axial orientation accuracy of the cut surface in the case of a single crystal substrate), the film thickness of the IDT electrode and reflector, and even the IDT electrode The center frequency may fluctuate due to variations in width or the like.
そこで、従来はレーザー・バーニング調整法により中心
周波数を設定していた。即ち、このレーザー・バーニン
グ調整法はＩＤＴ電極や反射器のメタルストリップ反射
格子にレーザービームにてトリミング製飾して反射器間
の実効対向距離を変化させ、これにより中心周波数を調
整する方法である。しかし、かかる調整法では周波数特
性も僅かではあるが変化してしまう上に複雑で高価な装
置を必要とし、かつ一度に多数の弾性表面波共振子を調
整することが不可能なため作業性の点で問題を有してい
る。Therefore, conventionally, the center frequency was set using the laser burning adjustment method. That is, this laser burning adjustment method is a method in which the IDT electrode or the metal strip reflection grating of the reflector is trimmed and decorated with a laser beam to change the effective facing distance between the reflectors, thereby adjusting the center frequency. . However, this adjustment method causes a slight change in frequency characteristics, requires complicated and expensive equipment, and makes it difficult to adjust many surface acoustic wave resonators at the same time. There are problems with this.
一方、グループ（溝）型反射器を有する弾性表面波共振
子においてはＩＤＴ電極の膜厚の外にグループの深さに
よっても中心周波数が変化する。On the other hand, in a surface acoustic wave resonator having a group (groove) type reflector, the center frequency changes depending not only on the film thickness of the IDT electrode but also on the depth of the group.
このため、この種の弾性表面波共振子ではドライエツチ
ング調整法により中心周波数を設定している。即ち、水
晶製の圧電基板にアルミニウム等の膜より成るＩＤＴ電
極や反射器を設けた場合には、ＩＤＴ電極や反射器をレ
ジストとして用いてガスプラズマにより圧電基板をエツ
チングし、又はＩＤＴ電極や反射器側をエツチングし、
これにより周波数の増減に対応させて弾性表面波（以下
、ＳＡＷと略記する）の伝搬速度を変化させ、中心周波
数を設定している。しかし、この調整法では同様に複雑
で高価な装置を必要とする上にＩＤＴ電極等の膜厚やグ
ループの深さが変化することから温度特性や周波数特性
が変化してしまう欠点がある。また、ＩＤＴ電極や反射
器をエッチソゲする場合にはＣ交（塩素）ガス等を、圧
電基板をエツチングする場合にはＣＦ、（テトラフロロ
メタン）ガス等を用いる必要があるため、エツチング対
象に応じてエツチングガスを変更しなければならず、作
業性の点で問題がある。For this reason, in this type of surface acoustic wave resonator, the center frequency is set by a dry etching adjustment method. That is, when an IDT electrode or reflector made of a film such as aluminum is provided on a piezoelectric substrate made of quartz, the piezoelectric substrate is etched with gas plasma using the IDT electrode or reflector as a resist, or the IDT electrode or reflector is etched using gas plasma. Etch the side of the vessel,
As a result, the propagation speed of surface acoustic waves (hereinafter abbreviated as SAW) is changed in accordance with the increase/decrease in frequency, and the center frequency is set. However, this adjustment method similarly requires complicated and expensive equipment, and has the disadvantage that temperature characteristics and frequency characteristics change because the thickness of the IDT electrode and the depth of the group change. In addition, when etching IDT electrodes and reflectors, it is necessary to use carbon dioxide (chlorine) gas, etc., and when etching piezoelectric substrates, it is necessary to use CF, (tetrafluoromethane) gas, etc., so depending on the object to be etched. Therefore, the etching gas must be changed, which poses a problem in terms of workability.
その他の周波数調整法として、弾性表面波共振子の上面
に誘電体膜を設け、ＳＡＷの伝搬速度を変化させて中心
周波数を設定する誘電体付着法が知られている。しかし
、この誘電体付着法では、スパッタ装置や蒸着装置等を
別個に必要とするため、装置規模が大きくなってしまう
上にりｉ性表面波共振子の単価が高価になってしまう。As another frequency adjustment method, a dielectric attachment method is known in which a dielectric film is provided on the top surface of a surface acoustic wave resonator and the center frequency is set by changing the propagation speed of the SAW. However, this dielectric deposition method requires a separate sputtering device, vapor deposition device, etc., which increases the scale of the device and also increases the unit price of the i-type surface wave resonator.
（問題点を解決するための手段）
本発明はこのような点を解決するためになされたもので
、圧電基板上に少なくとも設けたすだれ状電極の表面に
酸化膜を設け、ＳＡＷの伝搬速度を変化させて中心周波
数を設定する弾性表面波共振子の周波数調整方法を提供
することを目的とする。(Means for Solving the Problems) The present invention has been made to solve these problems, and it is possible to reduce the propagation speed of the SAW by providing an oxide film on the surface of at least the interdigital electrodes provided on the piezoelectric substrate. It is an object of the present invention to provide a frequency adjustment method for a surface acoustic wave resonator in which the center frequency is set by changing it.
（発明の実施例）
以下、本発明の実施例を図面を参照して詳細に説明する
。(Embodiments of the Invention) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
第１図は弾性表面波共振子の一例を示す斜視図、第２図
は第１図のＡ−Ａ線断面図であり、１は圧電基板を示し
ている。この圧電基板は水晶より形成され、板面の中央
にアルミニウム膜から成るＩＤＴ電極２．３が設けられ
、板面の両側にアルミニウム膜から成る反射器４．５が
それぞれ設けられている。ＩＤＴ電極２．３には外部電
極（図示せず）と接続するためのポンディングワイヤ６
．６の一端がそれぞれポンディングされている。FIG. 1 is a perspective view showing an example of a surface acoustic wave resonator, and FIG. 2 is a sectional view taken along the line A--A in FIG. 1, where 1 indicates a piezoelectric substrate. This piezoelectric substrate is made of quartz, has an IDT electrode 2.3 made of an aluminum film in the center of the plate surface, and reflectors 4.5 made of an aluminum film on both sides of the plate surface. The IDT electrode 2.3 has a bonding wire 6 for connecting to an external electrode (not shown).
．． 6 is bonded at one end.
かかる構成の弾性表面波共振子において、ポンディング
ワイヤ６．６を介してＩＤＴ電極２．３に高周波電気信
号を加えると、圧電基板１の中心周波数と高周波電気信
号の周波数が一致した時点で圧電基板１が共振して大き
な振動を起こす。In the surface acoustic wave resonator having such a configuration, when a high-frequency electric signal is applied to the IDT electrode 2.3 via the bonding wire 6.6, the piezoelectricity is activated when the center frequency of the piezoelectric substrate 1 and the frequency of the high-frequency electric signal match. The substrate 1 resonates and causes large vibrations.
次に、本発明に係る周波数調整方法について説明する。Next, a frequency adjustment method according to the present invention will be explained.
先ず、上記弾性表面波共振子をパッケージの所定位置に
グイポンディングし、続いてＩＤＴ電極２．３にポンデ
ィングワイヤ６．６をワイヤポンディングする。First, the surface acoustic wave resonator is wire-bonded to a predetermined position of the package, and then a bonding wire 6.6 is wire-bonded to the IDT electrode 2.3.
次に、このパッケージソゲした弾性表面波共振子を酸素
プラズマ中に配置し、第３図に示すように、ＩＤＴ電極
２．３及び反射器４．５の表面に酸化膜（ＡＪＬｚ○３
）７を形成する。この酸化膜７の形成工程では、プラズ
マ放電時間に対する中心周波数の変化量を検知し、所望
中心周波数を得るようにプラズマ放電時間を制御し、酸
化膜７を所定の膜厚に形成する。即ち、例えば、第４図
に示すように、製造時の弾性表面波共振子の中心周波数
がｆ、の場合には、プラズマ放電時間に対する中心周波
数（ＳＡＷの伝搬速度）の増大を検知し、その中心周波
数が所望の値ｆｏになった時点でプラズマ放電を停止し
、酸化膜７を所定膜厚に形成する。Next, this packaged surface acoustic wave resonator is placed in oxygen plasma, and as shown in FIG. 3, an oxide film (AJLz○3
) form 7. In the step of forming the oxide film 7, the amount of change in the center frequency with respect to the plasma discharge time is detected, the plasma discharge time is controlled to obtain a desired center frequency, and the oxide film 7 is formed to a predetermined thickness. That is, for example, as shown in FIG. 4, if the center frequency of the surface acoustic wave resonator at the time of manufacture is f, an increase in the center frequency (SAW propagation speed) with respect to the plasma discharge time is detected and the When the center frequency reaches a desired value fo, the plasma discharge is stopped and the oxide film 7 is formed to a predetermined thickness.
このように、ＩＤＴ電極２．３及び反射器４．５に所定
の膜厚で酸化膜７を形成する場合には、上述したように
、ダイポンディング等を行なった後に多数の弾性表面波
共振子を酸素プラズマ中に単に配置して中心周波数の変
化を検知すればよいので、一度に多数の弾性表面波共振
子の中心周波数を調整することができる上にプラズマ放
電を停止して酸化膜７を所定の膜厚に形成するだけであ
ることから簡単な作業により中心周波数を高精度で設定
することができる。また、酸化膜７を形成するだけなの
で、装置構成が簡単であり、しかも弾性表面波共振子の
周波数特性や温度特性が変化することもない。In this way, when forming the oxide film 7 with a predetermined thickness on the IDT electrode 2.3 and the reflector 4.5, as described above, after performing die bonding etc., a large number of surface acoustic wave resonators are formed. Since it is sufficient to simply place the oxide film 7 in oxygen plasma and detect the change in the center frequency, the center frequency of many surface acoustic wave resonators can be adjusted at once, and the plasma discharge can be stopped to remove the oxide film 7. Since the film is simply formed to a predetermined thickness, the center frequency can be set with high accuracy through simple operations. Further, since only the oxide film 7 is formed, the device configuration is simple, and the frequency characteristics and temperature characteristics of the surface acoustic wave resonator do not change.
上記実施例では、酸化膜７を酸素プラズマにより形成し
たが、弾性表面波共振子を酸化液に所定時間だけ浸漬す
る等により形成してもよい。In the above embodiment, the oxide film 7 was formed using oxygen plasma, but it may also be formed by immersing the surface acoustic wave resonator in an oxidizing solution for a predetermined period of time.
尚、ニオブ酸リチウム（ＬｉＮｂＯ３）やタンタル酸リ
チウム（ＬｉＴａ０３）等から成る圧電基板を有する弾
性表面波共振子であっても同様にＩＤＴ電極等に酸化膜
を形成して中心周波数を調整できるのは勿論である。Furthermore, even if the surface acoustic wave resonator has a piezoelectric substrate made of lithium niobate (LiNbO3) or lithium tantalate (LiTa03), the center frequency can be adjusted by forming an oxide film on the IDT electrode, etc. Of course.
また、本発明に係る調整方法は圧電基板上に、シングル
フェイズトランスジューサ電極を設けた弾性表面波共振
子にも適用できる。Further, the adjustment method according to the present invention can also be applied to a surface acoustic wave resonator in which a single-phase transducer electrode is provided on a piezoelectric substrate.
（発明の効果）
本発明によれば、圧電基板上に少なくとも設けたすだれ
状電極の表面に酸化膜を設け、ＳＡＷの伝搬速度を変化
させて中心周波数を設定するようにしたので、多数の弾
性表面波共振子を酸素プラズマ中に設置してプラズマ放
電時間を制御する等により作業性よく、しかも簡単な装
置構成で一度にこれらのりｉ性表面波共振子の中心周波
数を高精度で調整することができる。従って、品質的に
優れたりｉ性表面波共振子を安価に提供することができ
る。(Effects of the Invention) According to the present invention, an oxide film is provided on the surface of at least the interdigital electrode provided on the piezoelectric substrate, and the center frequency is set by changing the SAW propagation speed. By installing surface wave resonators in oxygen plasma and controlling the plasma discharge time, it is possible to adjust the center frequency of these i-type surface wave resonators at once with high precision with easy workability and a simple device configuration. Can be done. Therefore, it is possible to provide an i-type surface wave resonator with excellent quality and at low cost.
第１図は本発明に係る周波数調整方法を適用する弾性表
面波共振子の斜視図、第２図は第１図のＡ−Ａ線断面図
、第３図は本発明に係る周波数調整方法により酸化膜の
形成された弾性表面波共振子の断面図、第４図はプラズ
マ放電時間に対する中心周波数変化を示す特性図である
。
１・・・圧電基板、
２．３・・・ＩＤＴ電極、
４．５・・・反射器、
６・・・ポンディングワイヤ、
７・・・酸化膜。
第１図
第２図
第３図FIG. 1 is a perspective view of a surface acoustic wave resonator to which the frequency adjustment method according to the present invention is applied, FIG. 2 is a sectional view taken along the line A-A in FIG. FIG. 4, which is a cross-sectional view of a surface acoustic wave resonator with an oxide film formed thereon, is a characteristic diagram showing changes in center frequency with respect to plasma discharge time. DESCRIPTION OF SYMBOLS 1... Piezoelectric substrate, 2.3... IDT electrode, 4.5... Reflector, 6... Bonding wire, 7... Oxide film. Figure 1 Figure 2 Figure 3
Claims (1)
電極が少なくとも設けられている弾性表面波共振子にお
いて、前記すだれ状電極の表面に酸化膜を設けて前記弾
性表面波の伝搬速度を変化させ、中心周波数を設定する
ことを特徴とする弾性表面波共振子の周波数調整方法。 ２、該圧電基板上に該すだれ状電極と共に反射器が設け
られている弾性表面波共振子において、該反射器の表面
に該すだれ状電極と共に酸化膜を設けることを特徴とす
る特許請求の範囲第１項に記載の弾性表面波共振子の周
波数調整方法。[Claims] 1. In a surface acoustic wave resonator in which at least an interdigital electrode for exciting surface acoustic waves is provided on a piezoelectric substrate, an oxide film is provided on the surface of the interdigital electrode to excite the elastic A method for adjusting the frequency of a surface acoustic wave resonator, characterized by changing the propagation speed of a surface wave and setting a center frequency. 2. A surface acoustic wave resonator in which a reflector is provided on the piezoelectric substrate together with the interdigital electrode, characterized in that an oxide film is provided on the surface of the reflector together with the interdigital electrode. 2. The method for adjusting the frequency of a surface acoustic wave resonator according to item 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15543186A JPS6310909A (en) | 1986-07-02 | 1986-07-02 | Frequency adjusting method for surface acoustic wave resonator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15543186A JPS6310909A (en) | 1986-07-02 | 1986-07-02 | Frequency adjusting method for surface acoustic wave resonator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6310909A true JPS6310909A (en) | 1988-01-18 |
Family
ID=15605868
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15543186A Pending JPS6310909A (en) | 1986-07-02 | 1986-07-02 | Frequency adjusting method for surface acoustic wave resonator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6310909A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8933238B2 (en) | 2013-03-11 | 2015-01-13 | Saudi Basic Industries Corporation | Aryloxy-phthalocyanines of group III metals |
| US9040710B2 (en) | 2013-03-11 | 2015-05-26 | Saudi Basic Industries Corporation | Aryloxy-phthalocyanines of group IV metals |
-
1986
- 1986-07-02 JP JP15543186A patent/JPS6310909A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8933238B2 (en) | 2013-03-11 | 2015-01-13 | Saudi Basic Industries Corporation | Aryloxy-phthalocyanines of group III metals |
| US9040710B2 (en) | 2013-03-11 | 2015-05-26 | Saudi Basic Industries Corporation | Aryloxy-phthalocyanines of group IV metals |
| US9362509B2 (en) | 2013-03-11 | 2016-06-07 | Saudi Basic Industries Corporation | Aryloxy-phthalocyanines of group IV metals |
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