JPS6068711A - Piezoelectric thin film resonator - Google Patents
Piezoelectric thin film resonatorInfo
- Publication number
- JPS6068711A JPS6068711A JP17626983A JP17626983A JPS6068711A JP S6068711 A JPS6068711 A JP S6068711A JP 17626983 A JP17626983 A JP 17626983A JP 17626983 A JP17626983 A JP 17626983A JP S6068711 A JPS6068711 A JP S6068711A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- piezoelectric
- silicon
- electrode
- substrate
- 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
- 239000010409 thin film Substances 0.000 title claims abstract description 44
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 30
- 239000000758 substrate Substances 0.000 claims abstract description 30
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 29
- 239000010703 silicon Substances 0.000 claims abstract description 29
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 21
- 229910052814 silicon oxide Inorganic materials 0.000 claims abstract description 21
- 239000010408 film Substances 0.000 claims description 22
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical group N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 abstract description 15
- 229910052581 Si3N4 Inorganic materials 0.000 abstract description 14
- 238000005530 etching Methods 0.000 abstract description 13
- 239000011248 coating agent Substances 0.000 abstract description 3
- 238000000576 coating method Methods 0.000 abstract description 3
- 230000007613 environmental effect Effects 0.000 abstract description 2
- 239000000126 substance Substances 0.000 abstract 3
- 150000004767 nitrides Chemical class 0.000 abstract 1
- 239000000463 material Substances 0.000 description 11
- 238000000034 method Methods 0.000 description 9
- 238000004519 manufacturing process Methods 0.000 description 7
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 5
- 239000013078 crystal Substances 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 239000007788 liquid Substances 0.000 description 4
- 239000002253 acid Substances 0.000 description 3
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- WUPHOULIZUERAE-UHFFFAOYSA-N 3-(oxolan-2-yl)propanoic acid Chemical compound OC(=O)CCC1CCCO1 WUPHOULIZUERAE-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- YCIMNLLNPGFGHC-UHFFFAOYSA-N catechol Chemical compound OC1=CC=CC=C1O YCIMNLLNPGFGHC-UHFFFAOYSA-N 0.000 description 2
- 230000005284 excitation Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 238000001755 magnetron sputter deposition Methods 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 238000000206 photolithography Methods 0.000 description 2
- 230000010287 polarization Effects 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- FDNAPBUWERUEDA-UHFFFAOYSA-N silicon tetrachloride Chemical compound Cl[Si](Cl)(Cl)Cl FDNAPBUWERUEDA-UHFFFAOYSA-N 0.000 description 2
- -1 Boro Phospho Chemical class 0.000 description 1
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 description 1
- 206010041349 Somnolence Diseases 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052980 cadmium sulfide Inorganic materials 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920002120 photoresistant polymer Polymers 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 230000001568 sexual effect Effects 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
- 238000001771 vacuum deposition Methods 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
- H03H3/02—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 piezoelectric or electrostrictive resonators or networks
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
Description
【発明の詳細な説明】
〔発明の属する技術分野〕
本発明は圧電薄膜共振子に関し、詳しく言えば半導体結
晶基板を用いた圧電薄膜共振子に関する。DETAILED DESCRIPTION OF THE INVENTION [Technical Field to which the Invention Pertains] The present invention relates to a piezoelectric thin film resonator, and more specifically to a piezoelectric thin film resonator using a semiconductor crystal substrate.
近年、材料技術や加工技術の進歩に伴ない電子部品の１
１積化が進み、その集積度も大規模なものとなっている
。In recent years, with advances in material technology and processing technology, the number of electronic components has increased.
The number of integrated devices is increasing, and the degree of integration is also increasing.
しかしながら共振子やフィルタ等受動部品についての集
積化は遅れており、通信機器あるいはＯＡ機器等の応用
分野において、Ｖ、Ｉ（ＦあるいはＵ ＨＦ帯域で使用
可能な小型の共振子の出現が望まれている。However, the integration of passive components such as resonators and filters is lagging behind, and the emergence of small resonators that can be used in the V, I (F, or U HF bands) is desired in application fields such as communication equipment and OA equipment. ing.
従来、共振子やフィルタとして水晶等圧電基板の厚み縦
振動を利用したものが実用化され数多く使用されている
。ところが、この圧電基板の基本厚み振動を利用した素
子は、加工技術上及び圧電基板の機械的強度の制約から
圧′ル基板の厚みをせいぜい数十μｍ程度とするにとど
まり、したがって利用可能な共振周波数も数十ＭＨｚが
殆んど限界となっていた。それ以上の周波数を必要とす
る場合には、高次厚み振動を利用することとなるが、高
次に々ると励振効率や尖鋭度Ｑが低下するため使用しに
〈〈実用的でなかった。BACKGROUND ART Conventionally, resonators and filters that utilize the longitudinal vibration of the thickness of piezoelectric substrates, such as crystals, have been put into practical use and are widely used. However, in the case of an element that utilizes the basic thickness vibration of a piezoelectric substrate, the thickness of the piezoelectric substrate is limited to a few tens of micrometers at most due to processing technology and mechanical strength constraints of the piezoelectric substrate, and therefore, the available resonance is limited. Frequency was almost limited to several tens of MHz. If a higher frequency is required, higher-order thickness vibrations will be used, but as the frequency increases, the excitation efficiency and sharpness Q will decrease, making it impractical to use. .
これに対し、最近、厚み振動等の基本モードあして、半
導体結晶基板を使用した圧電薄膜共振子が研究されてい
る。例えば、１９８０年ＩＢＢＥ学会の超音波７ンボジ
ウムにおける論文集あるいは１９８３年第１２回ＥＭシ
ンポジウムにおける論文集等において発表されているも
ので、第１図ないし第２図に示す如きものが知られてい
る。尚、第１図は圧電膜として酸化亜鉛（ＺｎＯ）を用
いた圧電薄膜共振子の斜視図であり、第２図はその構成
を示すものでＡ−Ａ’面における断面図である。On the other hand, piezoelectric thin film resonators using semiconductor crystal substrates have recently been studied for basic modes such as thickness vibration. For example, the ones shown in Figures 1 and 2 are known as those published in the 1980 IBBE Society Ultrasonics 7th Symposium Proceedings, 1983 12th EM Symposium, etc. . Incidentally, FIG. 1 is a perspective view of a piezoelectric thin film resonator using zinc oxide (ZnO) as a piezoelectric film, and FIG. 2 is a sectional view taken along the plane AA' showing the structure thereof.
ここで、中央部に凹部が形成されている振動子支持体止
はシリコン（Ｓ【）基板ｌとその両面に積層した酸化シ
リコン（８ｉ０ｚ）薄膜２から成る。その酸化シリコン
（８ｉ０．）薄膜２の上に第１の電極３が形成されてい
る。第１（１）電極３の上に酸化亜鉛（ＺｎＯ）圧電膜
４が形成され、さらに、圧電膜４の上に第２の成極５が
形成されている。酸化シリコン（８ｉ０．）薄膜２は共
振子としては必ずしも必要なものではないが、酸化亜鉛
（ＺｎＯ）圧電膜４に対して異符号の温度係数を有する
ことから、この性質を利用して零温度係数化を図る為に
設けられている。このようにして作られたこの圧電薄膜
共振子は、次の様な特長を持っている。即ち、■ １０
０Ｍｆ（ｚ〜数ＧＨｚの周波数帯において基本モードあ
るいは低次モードで動作する。Here, the vibrator support member having a recess formed in the center is composed of a silicon (S) substrate 1 and a silicon oxide (8iOz) thin film 2 laminated on both surfaces thereof. A first electrode 3 is formed on the silicon oxide (8i0.) thin film 2. A zinc oxide (ZnO) piezoelectric film 4 is formed on the first (1) electrode 3, and a second polarization 5 is further formed on the piezoelectric film 4. The silicon oxide (8i0.) thin film 2 is not necessarily required as a resonator, but since it has a temperature coefficient of the opposite sign to the zinc oxide (ZnO) piezoelectric film 4, this property can be used to reduce the temperature to zero. It is provided for the purpose of coefficientization. This piezoelectric thin film resonator made in this way has the following features. That is, ■ 10
It operates in the fundamental mode or low-order mode in the frequency band from 0Mf (z to several GHz).
■ 電気機械結合係数Ｋｔが大きく広帯域化が計れる。■ The electromechanical coupling coefficient Kt is large and a wide band can be achieved.
■ 圧電膜と異符号の弾性スティフネスに対する温度係
数をもつ酸化シリコン（８ｉ０．）膜との組合せにより
零温度係数が得られる。(2) A zero temperature coefficient can be obtained by combining a piezoelectric film with a silicon oxide (8i0.) film that has a temperature coefficient of elastic stiffness of opposite sign.
■ 共振子の超小型化が可能である。■ It is possible to make the resonator ultra-small.
■ 共振子の製作工程が一般的な集積回路とコンパチブ
ルであるため、集積回路内に組み込むことが可能である
。■ The resonator manufacturing process is compatible with general integrated circuits, so it can be incorporated into integrated circuits.
（リ 従来のバルク波共振子のように板ばね等で支持す
る必要がなく、使い易い。(l) Unlike conventional bulk wave resonators, there is no need to support it with leaf springs, etc., making it easy to use.
等である。etc.
ところが、このようなシリコン（Ｓｉ） 基板の中央部
に凹部を形成した圧電薄膜共振子では、■酸化シリコン
（８ｉ０２）膜がシリコン（Ｓｌ）基板と異符号の弾性
ステイフネスに対する温度係数をもつため、破損したり
ふくれるという現象を呈することがある。■耐酸・耐ア
ルカリ・耐湿等の点で圧電膜の保護が不十分で信頼性に
難がある。■シリコン（Ｓｉ）基板を異方性エツチング
により加工する場合、酸化シリコン（８ｉ０２）表面が
荒されやすく、従って酸化シリコン（Ｓｉｎ２）膜厚を
あまり薄くすることができない、という問題点があった
。However, in such a piezoelectric thin film resonator in which a recess is formed in the center of a silicon (Si) substrate, ■The silicon oxide (8i02) film has a temperature coefficient of elastic stiffness with a different sign from that of the silicon (Sl) substrate; It may cause damage or swelling. ■The piezoelectric film is not sufficiently protected in terms of acid resistance, alkali resistance, moisture resistance, etc., and reliability is poor. (2) When processing a silicon (Si) substrate by anisotropic etching, there is a problem that the silicon oxide (8i02) surface is easily roughened, and therefore the silicon oxide (Sin2) film cannot be made very thin.
（発明の目的〕
本発明は、超小型で高周波帯域で動作するとともに、信
頼性の高い圧電薄膜共振子を提供することを目的とする
。(Objective of the Invention) An object of the present invention is to provide a piezoelectric thin film resonator that is ultra-small, operates in a high frequency band, and has high reliability.
上記目的を達成するために、本発明においては少なくと
も一面にチン化シリコン（ＳｌｓＮ４）を主成分とする
薄膜を積層した７リコン（Ｓｉ）基板の中央部を薄肉に
加工することにより振動子支持体を形成し、この振動子
支持体上に少なくとも圧電膜を含む圧電体及び励振用電
極をそれぞれ形成し、さらに少なくとも前記圧電体を酸
化シリコン（Ｓｉｎ、）を主成分とする被覆体で覆った
圧電薄膜共振子を提供する。In order to achieve the above object, in the present invention, a resonator support is formed by processing the central part of a silicon (Si) substrate, on which a thin film mainly composed of silicon nitride (SlsN4) is laminated on at least one surface, to be thin. a piezoelectric material including at least a piezoelectric film and an excitation electrode are formed on the vibrator support, and furthermore, at least the piezoelectric material is covered with a coating mainly composed of silicon oxide (Sin). Provides a thin film resonator.
以下、本発明の一実施例について図面を参照して説明す
る。第３図は、本発明に係る圧電薄膜共振子の斜視図で
あり、第４図は、本発明に係る圧電薄膜共振子の構成を
示すものでＢ−ｄにおける断面図である。尚、図面中同
−箇所については同一符号を付している。An embodiment of the present invention will be described below with reference to the drawings. FIG. 3 is a perspective view of a piezoelectric thin film resonator according to the present invention, and FIG. 4 is a sectional view taken along line B-d showing the structure of the piezoelectric thin film resonator according to the present invention. In addition, the same reference numerals are given to the same parts in the drawings.
まず、シリコン（Ｓｉ）基板ｌｏの両面にはチン化シリ
コン（Ｓｉ３Ｎ４）を主成分とする薄膜（以下、［チン
化シリコン（８ｒ ｓ Ｎ４ ） 系ｔａ Ｍ Ｊ ｃ
！：いう。）１１を積層しである。さらに、チン化シリ
コン（Ｓｉ３Ｎ４ ）系薄膜１１の片面の一部を、例え
ばり７ 酸（Ｉ（３ＰＯ４） を使い、方形にエツチン
グ加工する。そして、方形の窓１２を開けたｔｉｖ膜１
１面側からシリコン（Ｓｉ）基板１ｏを異方性エツチン
グし、中央部が凹部形をした振動子支持体」を形成して
いる。尚、シリコン（Ｓｉ）基板１０及び方形の窓１２
を加工していない面のチン化シリコン（Ｓｉ３Ｎ４ ）
系薄膜１１の厚みに、所望する共振子の共振周波数及び
７リコン（Ｓｉ）基板１０の中央部を加工するエツチン
グ液に対するエツチング量等から定められる。チン化シ
リコン（Ｓ １ｓＮ４） 糸導ＰＡｌｌは化学的にも熱
的にも安定であるため、従来の酸化シリコン（Ｓｉｎ２
）に比べ極めて薄いもので十分である。さらに、機械的
性質が優れているので、酸化シリコン（Ｓｉｎ、）の場
合のように破損したりふくれたりする虞れがない。また
、薄膜１１の組成は必ずしも１００％００％テラコン（
ＳｊａＮ４）である必要はなく、チン化シリコン（Ｓ！
３Ｎ＋）を主成分とし化学的・物理的にチン化シリコン
（Ｓ！ｓＮ＜ ） と同様の物性を有するものであれば
足りる。次に、中央部が薄肉の振動子支持体口の上に＆
′ｉ第１の電極１４が形成されている。First, on both sides of a silicon (Si) substrate lo, a thin film mainly composed of silicon nitride (Si3N4) (hereinafter, [silicon nitride (8r s N4) system ta M J c
! :say. ) 11 are laminated. Furthermore, a part of one side of the silicon nitride (Si3N4) thin film 11 is etched into a rectangular shape using, for example, 7-acid (I(3PO4)).
A silicon (Si) substrate 1o is anisotropically etched from one side to form a vibrator support having a concave central portion. Note that a silicon (Si) substrate 10 and a rectangular window 12
Chinized silicon (Si3N4) on the unprocessed surface
The thickness of the system thin film 11 is determined based on the desired resonant frequency of the resonator, the etching amount of the etching liquid used to process the central portion of the silicon (Si) substrate 10, and the like. Silicon oxide (S 1sN4) Thread-conducting PAll is chemically and thermally stable, so it is better than conventional silicon oxide (S 1sN4)
) is sufficient. Furthermore, because of its excellent mechanical properties, there is no risk of breakage or blistering as is the case with silicon oxide (Sin). Furthermore, the composition of the thin film 11 is not necessarily 100%, 00% Terracon (
It does not need to be silicon chloride (SjaN4), but silicon chloride (SjaN4).
3N+) as a main component and chemically and physically have the same physical properties as silicon tinide (S!sN<). Next, place the central part on top of the thin-walled vibrator support opening.
'i A first electrode 14 is formed.
この第１の電極１４は圧電体１５に゛底圧を印加し励振
させるためのものであり、圧電薄膜共振子の共振特性を
考慮してその形状等が定められる。このｉＨ１の電極１
４は、例えばＡｌ 、 Ｃｒ −Ａｕ 、 Ｔｉ −Ａ
ｕ等を成極材料として形成することができる。一般的に
％第１の４極１４を振動子支持体目上に形成する場合、
第１の電極１４の振動部分が、振動子支持体すの凹部１
３の中央に略対向する位置に在るように形成する（？！
！、４図）。これは、振動部分の厚み縦振動のみを利用
し、不要振動による影響をなくすためである。第１の電
極１４の振動部分上には圧電膜を含む圧電体１５が形成
される。This first electrode 14 is for applying a bottom pressure to the piezoelectric body 15 to excite it, and its shape etc. are determined in consideration of the resonance characteristics of the piezoelectric thin film resonator. Electrode 1 of this iH1
4 is, for example, Al, Cr-Au, Ti-A
u, etc. can be formed as a polarizing material. Generally, when forming the first quadrupole 14 on the vibrator support,
The vibrating portion of the first electrode 14 is located in the recess 1 of the vibrator support body.
Form it so that it is located almost opposite the center of 3 (?!
! , Figure 4). This is to utilize only the thickness longitudinal vibration of the vibrating part and eliminate the influence of unnecessary vibrations. A piezoelectric body 15 including a piezoelectric film is formed on the vibrating portion of the first electrode 14 .
圧電体１５は、所望の共振特性だより、圧電膜と誘電体
膜との組合せから成る多屑購造とすることも゛できる。The piezoelectric body 15 can also be manufactured in bulk, consisting of a combination of a piezoelectric film and a dielectric film, depending on the desired resonance characteristics.
圧電体１５を構成する圧電膜は所望する共振周波数やそ
の温度係数及び電気機械結合係数の大きさ等からその材
質が決定されるが、例えば酸化亜鉛（ＺｎＯ） 、チン
化アルミニウｌ、（ＡＩＮ） 。The material of the piezoelectric film constituting the piezoelectric body 15 is determined based on the desired resonance frequency, its temperature coefficient, the magnitude of electromechanical coupling coefficient, etc., and examples thereof include zinc oxide (ZnO), aluminum tinide, (AIN), etc. .
硫化カドミニウム（Ｃｄ８）等が周知である。これらの
中で、特に酸化亜鉛（ＺｎＯ）は、眠気機械結合係数が
大きくしかも膜の形成が容易であることから好適である
。この圧電体１５の厚みｔ（＋＋＋＋ｎ）は、所望の共
振周波数をｆ（Ｈｚ）、少なくとも圧電膜を含む圧電体
１５の複合振動膜固有の周波数定数をＮ（Ｈｚ−關）と
すれば、おおよそｆ＝Ｎ／ｌなる関係から定められる。Cadmium sulfide (Cd8) and the like are well known. Among these, zinc oxide (ZnO) is particularly suitable because it has a large drowsiness mechanical coupling coefficient and is easy to form a film. The thickness t(++++n) of the piezoelectric body 15 is approximately determined by assuming that the desired resonance frequency is f (Hz) and the frequency constant specific to the composite vibrating membrane of the piezoelectric body 15 including at least the piezoelectric membrane is N (Hz-). It is determined from the relationship f=N/l.
圧電体１５の上には、第２の電極１６が形成される。こ
の第２の電極１６は、第１の電極１４と共に圧電体１５
に”電圧を印加し励振させるだめのものである。従って
、第２の電極１６は、振動部分が圧電体１５を介し第１
の電極１４と略対向する位置に形成するのが望ましい。A second electrode 16 is formed on the piezoelectric body 15 . This second electrode 16 is connected to the piezoelectric body 15 together with the first electrode 14.
The purpose of the second electrode 16 is to apply a voltage to the
It is desirable to form the electrode 14 at a position substantially facing the electrode 14 .
尚、第１の電極１４と第２の電極１６は必ずしも上述の
実施例の如く、圧電体１５の上下にある必要はない。即
ち、圧電体１５を励振させるため圧電体１５の構造等に
応じて配置・形成するからである。第２の′電極１６は
第１の電極１４と同じ材質で造ることができる。さらに
、圧電体１５は被覆体１７によって略すっばり覆われて
いる。このとき、第１．第２の′成極１４，１６につい
ても例えばリード線取付部分を除き被覆体１７で覆って
もよい。この被覆体１７は、酸化シリコン（Ｓｉｎ、）
を主成分とするもので、弾性ステイフネスに対する正の
温度係数をもつ。従って、一般に負の温度係数をもつ圧
電膜材料に対し温度補償ができる為共振子の温度特性を
良好なものとすることができる。さらに、酸化シリコン
（Ｓｉｎ、）膜はイヒ学白りに安定であるから、圧電体
１．５や各電極１４．１６を外界あるいは周囲雰囲気か
ら保護するのに適し耐酸健耐アルカリあるいは耐湿の点
から共振子の１ｇ頼性を高めることができる。また、被
覆体１７の組成は必ずしも１ｏｏｓ酸化シリコン（Ｓｉ
ｎ、）である必要はなく、例えば酸化７リコン（８ｉ０
２）にリンを数％〜１０チ程度ドープしたＰＳＧ（Ｐｈ
ｏｓｐＨｏ ８ｉ ｌ １ｃａｔｅ Ｇｌａｓｓ）や、
ｙｌ？ ロンと１ノンをドープした１３ Ｐ Ｓ Ｇ
（Ｂｏｒｏ Ｐｈｏｓｐｈｏ Ｓｉ ＋ １ｃａｔｅ
Ｇｌａｓｓ）等でも良い。Note that the first electrode 14 and the second electrode 16 do not necessarily need to be located above and below the piezoelectric body 15 as in the above embodiment. That is, in order to excite the piezoelectric body 15, it is arranged and formed according to the structure of the piezoelectric body 15, etc. The second electrode 16 can be made of the same material as the first electrode 14. Furthermore, the piezoelectric body 15 is substantially completely covered by the covering body 17. At this time, the first. The second polarizations 14 and 16 may also be covered with a covering 17 except for the lead wire attachment portions, for example. This covering 17 is made of silicon oxide (Sin).
It has a positive temperature coefficient for elastic stiffness. Therefore, since temperature compensation can be performed for piezoelectric film materials that generally have a negative temperature coefficient, it is possible to improve the temperature characteristics of the resonator. Furthermore, since the silicon oxide (Sin) film is extremely stable, it is suitable for protecting the piezoelectric body 1.5 and each electrode 14.16 from the outside world or the surrounding atmosphere in terms of acid resistance, alkali resistance, and moisture resistance. The reliability of the resonator can be increased by 1 g. Furthermore, the composition of the covering 17 is not necessarily 100s silicon oxide (Si).
n, ), for example, 7-licon oxide (8i0
2) PSG (Ph
ospHo 8i l 1cate Glass) and
yl? 13 P S G doped with Ron and 1 Non
(Boro Phospho Si + 1cate
Glass) etc. may also be used.
次に、本発明に係る圧電薄膜共振子をどのように製造す
るか、その一実施例を説明する。第５図はその製造工程
を示す説明図である。まず、第５図ａに示す如く、いわ
ゆる結晶面を表わすミラー指数で（１００）面をなすシ
リコン（Ｓｉ）基板１０の両面にチン化シリコン（Ｓｉ
３Ｎ４ ）を主成分とする薄膜１１をＣＶ Ｄ （Ｃｂ
ｅｍｉｃａｌ Ｖａｐｏｒ Ｄｅｐｏｓｉｔｉｏｎ）法
により形成する。このチン化シリコン（ＳｉｓＮ４）系
薄膜１１は化学的にも熱的にも極めて安定であり、シリ
コン（Ｓｉ）基板１０のエツチング液に対するエツチン
グ速度がら最小厚さが決定される。Next, an example of how to manufacture the piezoelectric thin film resonator according to the present invention will be described. FIG. 5 is an explanatory diagram showing the manufacturing process. First, as shown in FIG.
The thin film 11 mainly composed of Cb
It is formed by the chemical vapor deposition method. This silicon nitride (SisN4) thin film 11 is extremely stable both chemically and thermally, and its minimum thickness is determined by the etching rate of the silicon (Si) substrate 10 with respect to the etching solution.
次に第５図すに示す如く、フォトレジスＨ−マスキング
材として用い、シリコン（Ｓｉ）基板裏面のチン化シリ
コン（ＳｉｓＮ４）系薄膜１１の一部分をリン酸（Ｈｓ
Ｐ ０４ ）でエツチングして方形の窓１２を開ける
。この窓１２はシリコン（８ｉ）基板を異方性エツチン
グする際のゲージとなるもので、その大きさは圧電体１
５の外形寸法を考慮して定められる。なお、窓１２の形
状は円形であっても差し支えない。いずれにしてもシリ
コン（Ｓｉ）基板は異方性エツチングすると、結晶面（
１１１）に浴ってエツチングされるからである。その次
に第５図Ｃに示す如く、方形の窓１２を開けた方のチン
化シリコン（ＳｉｓＮ４）系薄膜１１をマスクとして利
用し、例えばＰｌｉＤ液を用いてシリコン（Ｓｉ）基板
１０の異方性エツチングを行ないピラミッド形の穴１３
を形成する。ここでＰＨＤ液とは、ピロカテコールＣａ
ｄ４（ＯＨ）ｚ 、エチレンジアミ：ｙＮＨ。Next, as shown in FIG. 5, a portion of the silicon nitride (SisN4) thin film 11 on the back surface of the silicon (Si) substrate was heated using phosphoric acid (Hs) as a photoresist H-masking material.
P 04 ) to open the square window 12. This window 12 serves as a gauge when anisotropically etching a silicon (8i) substrate, and its size is determined by the size of the piezoelectric material 1.
It is determined by considering the external dimensions of 5. Note that the window 12 may have a circular shape. In any case, when a silicon (Si) substrate is anisotropically etched, the crystal plane (
111) and is etched. Next, as shown in FIG. 5C, the silicon (SiSN4) thin film 11 with the rectangular window 12 opened therein is used as a mask, and the silicon (Si) substrate 10 is anisotropically coated with, for example, PliD liquid. Pyramid hole 13 for sexual etching
form. Here, PHD liquid refers to pyrocatechol Ca
d4(OH)z, ethylenediamine:yNH.
（ＣＨ，）、 ＮＨ，、及び水Ｈ，０の混合液である。It is a mixture of (CH,), NH, and water H,0.
この液はエツチング速度の結晶方位依存性が大きい。The etching rate of this solution is highly dependent on crystal orientation.
従って、−辺がミラー指数で（１１０）方向に平行な矩
形を底面としく１１１）面を斜面とするピラミッド形の
穴が、窓１２に外接して堀れることになる。このように
して中央部が薄肉の振動子支持体」を造ることができる
。振動子支持体■が出来たら、窓１２を開けてない方の
チン化シリコン（ＳｆｓＮ４）系薄膜ｌｌ上に第１の電
極１４を形成する。この形成は、フォトリングラフィや
リフトオフ法あるいは金属マスク法等の手法を用い真空
蒸着等により行うことができる（第５図ｄ）。圧電体１
５は、第１の電極１４の上に例えばＲＦマグネトロンス
パッタリング法により形成される（第５図ｅ）。さらに
、第５図ｆに示す様に、圧電体１５の上に第２の電極１
６を形成する。この場合、フォトリングラフィの手法に
よると圧電体１５の表面を損傷する虞れがあるので、金
属マスクを用いて真空蒸着法によるのが望ましい。最後
に、酸化シリコン（８ｉ０２）を主成分とする被覆体１
７ｆＲ，Ｆマグネトロンスパッタリング法等により形成
することによ１）（８５図ｇ）、本発明に係る圧電薄膜
共振子を製作することができる。Therefore, a pyramid-shaped hole is dug circumscribing the window 12, with the − side being the Miller index, the base being a rectangle parallel to the (110) direction, and the 111) plane being the slope. In this way, it is possible to create a vibrator support with a thin central portion. Once the vibrator support body 1 is completed, the first electrode 14 is formed on the silicon nitride (SfsN4) thin film 11 on the side where the window 12 is not opened. This formation can be performed by vacuum evaporation or the like using techniques such as photolithography, lift-off method, or metal mask method (FIG. 5d). Piezoelectric body 1
5 is formed on the first electrode 14 by, for example, an RF magnetron sputtering method (FIG. 5e). Further, as shown in FIG. 5f, a second electrode 1 is placed on the piezoelectric body 15.
form 6. In this case, since the photolithography method may damage the surface of the piezoelectric body 15, it is preferable to use a vacuum evaporation method using a metal mask. Finally, a coating 1 mainly composed of silicon oxide (8i02)
The piezoelectric thin film resonator according to the present invention can be manufactured by forming it by a 7fR,F magnetron sputtering method or the like (1) (Fig. 85g).
上述した製造工程では、チン化シリコン（ＳｊｓＮ４）
系薄膜１１を積層し中央部を薄肉に加工したシリボン基
板１０上に、圧電体１５や各第１の電極１４、第２の電
極１６をそれぞれ形成していったが、これに限定される
ことはない。即ち、第６図に示す如く、チン化シリコン
（Ｓｉ３Ｎ４） 系薄膜１１を積層したシリコン基板１
０そのものに、第１の電極１４、圧電体１５、第２の電
極１６及び被覆体１７をそれぞれ形成する（第６図ａ
−ｄ ）。In the manufacturing process described above, silicon nitride (SjsN4)
Although the piezoelectric body 15, each of the first electrodes 14, and the second electrodes 16 were formed on the silicon ribbon substrate 10 in which the system thin films 11 were laminated and the central portion was processed to be thin, the present invention is not limited to this. There isn't. That is, as shown in FIG. 6, a silicon substrate 1 on which a silicon nitride (Si3N4) thin film 11 is laminated.
0 itself, a first electrode 14, a piezoelectric body 15, a second electrode 16, and a covering 17 are respectively formed (see FIG. 6a).
-d).
次に、Ｐ ＨＤ液のマスクに使えるＡｇ、Ａｕ、Ｃｕ。Next, Ag, Au, and Cu that can be used as a mask for PHD liquid.
Ｔａ 等の金属膜１９を形成する（第６図ｅ）。その後
、シリコン基板ＩＯを異方性エツチングにより中央部が
薄肉となるように加工しく第６図ｆ）。A metal film 19 such as Ta is formed (FIG. 6e). Thereafter, the silicon substrate IO is processed by anisotropic etching so that the central portion becomes thinner (FIG. 6f).
最後罠金属膜１９をエツチングにより除去する（第６図
ｇ）ことによっても、本発明に係る圧電薄膜共振子を製
作することができる。The piezoelectric thin film resonator according to the present invention can also be manufactured by removing the last trapping metal film 19 by etching (FIG. 6g).
この製造工程によれば、圧電体１５や各電極１４．１６
を形成した後、シリコン基板１０の異方性エツチングを
行なうので、共振子の振動部分即ち、薄膜部分における
熱や異種拐料の使用による応力歪を極力小さく押えるこ
とができ耐プロセス性も良好なものとすることができる
。According to this manufacturing process, the piezoelectric body 15 and each electrode 14.16
After forming the silicon substrate 10, anisotropic etching is performed on the silicon substrate 10, so that the stress strain caused by heat and the use of foreign particles in the vibrating part of the resonator, that is, the thin film part, can be kept to a minimum, and the process resistance is also good. can be taken as a thing.
本発明によれば、少なくとも一面にチン化シリコン（Ｓ
ｊｓＮｉ）系薄膜に！Ｒ層したシリコン（Ｓｉ）基板の
中央部を薄肉に加工しているので、振動部分薄膜の機械
的性質が向上し、破伊したりふくれたりする欠陥が減少
し超小型で高帯域用の圧電薄膜共振子を得ることができ
る。さらに、圧電体を酸化シリコン（Ｓｉｎ２）で覆っ
ているので、従来の共振子と同様に温度特性に対する補
償が出来るだけでなく、この酸化シリコン（８ｉ０２）
は圧電体に対する保護層として作用し、特に湿度に対し
て不安定である圧電体全有効に保設する。従って、耐環
境性も優れている。According to the present invention, silicon tinide (S) is provided on at least one surface.
jsNi) type thin film! Since the central part of the R-layered silicon (Si) substrate is processed to be thin, the mechanical properties of the vibrating thin film are improved, and defects such as cracking and bulging are reduced, making it possible to create an ultra-compact, high-bandwidth piezoelectric device. A thin film resonator can be obtained. Furthermore, since the piezoelectric body is covered with silicon oxide (Sin2), it is possible not only to compensate for temperature characteristics like a conventional resonator, but also to compensate for the temperature characteristics as in a conventional resonator.
acts as a protective layer for the piezoelectric material and effectively preserves the entire piezoelectric material, which is particularly unstable with respect to humidity. Therefore, it also has excellent environmental resistance.
第１図は従来の圧電薄膜共振子を示す斜視図、流側に係
る圧電薄膜共振子を示す斜視図、第４図発明の一実施例
に係る圧電薄膜共振子の製造工程を示す説明図、第６図
は他の例に係る製造工程を示す説明図である。
１、ｔｏ・・・シリコン（Ｓｉ）基板
旦４Ｊ・・・振動子支持体
１１・・・チン化シリコン（ＳｉｓＮ４）を主成分とす
る薄膜３．１４・・・第１の電極 ４・・・・圧電膜１
５・・・圧′環体 ５，１６・・・第２の電極１７・・
・酸化シリコン（Ｓｉｎ、）を主成分とする薄膜１９・
・・金属膜
代理人 弁理士 則 近 憲 佑 （ほか１名）第１図
＠ ２ 図
第 ３ 図 （ｄ）
ｔｄ＞
／Ｊ ／ｆ
（１１ン
第 ５ 図 第 ６ 図FIG. 1 is a perspective view showing a conventional piezoelectric thin film resonator, a perspective view showing a piezoelectric thin film resonator on the flow side, and FIG. 4 an explanatory diagram showing a manufacturing process of a piezoelectric thin film resonator according to an embodiment of the invention. FIG. 6 is an explanatory diagram showing a manufacturing process according to another example. 1, to...Silicon (Si) substrate 4J...Resonator support 11...Thin film mainly composed of silicon oxide (SisN4) 3.14...First electrode 4...・Piezoelectric film 1
5... pressure ring body 5, 16... second electrode 17...
・Thin film whose main component is silicon oxide (Sin) 19・
...Metal film agent Patent attorney Kensuke Chika (and 1 other person) Figure 1 @ 2 Figure 3 (d) td> /J /f (11 Figure 5 Figure 6
Claims (1)
成分とする薄膜を積層したシリコン（Ｓｉ）基板を、他
面から積層面に向って中央部を薄肉に加工した撮動子支
持体と、この据動子支持体のテラ化７リコン（Ｓｉ３Ｎ
、） を主成分とする薄膜上に、少なくとも圧這膜を含
んで形成した圧電体と、この圧或体を励振させる電極と
、酸化シリコン（Ｓｉｎ、）を主成分とし、少なくとも
前記圧電体を覆う被覆体とから成る圧電薄膜共振子。An image sensor support body made of a silicon (Si) substrate laminated with a thin film mainly composed of TERRA silicon (8+gN4) on at least one side, and a central part made thinner from the other side toward the laminated surface; Tera-7 recon (Si3N) of the child support
, ), a piezoelectric body formed on a thin film containing at least a piezoelectric film as a main component, an electrode for exciting this piezoelectric body, and a piezoelectric body mainly composed of silicon oxide (Sin, ), on which at least the piezoelectric body is formed. A piezoelectric thin film resonator consisting of a covering body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17626983A JPS6068711A (en) | 1983-09-26 | 1983-09-26 | Piezoelectric thin film resonator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17626983A JPS6068711A (en) | 1983-09-26 | 1983-09-26 | Piezoelectric thin film resonator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6068711A true JPS6068711A (en) | 1985-04-19 |
Family
ID=16010614
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17626983A Pending JPS6068711A (en) | 1983-09-26 | 1983-09-26 | Piezoelectric thin film resonator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6068711A (en) |
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6382116A (en) * | 1986-09-26 | 1988-04-12 | Matsushita Electric Ind Co Ltd | Piezoelectric thin film resonator and its manufacture |
| JP2001203558A (en) * | 1999-11-11 | 2001-07-27 | Murata Mfg Co Ltd | Piezoelectric resonator, filter and electronic device |
| JP2001211053A (en) * | 1999-11-17 | 2001-08-03 | Murata Mfg Co Ltd | Piezoelectric resonator, electronic component and electronic apparatus |
| JP2005209889A (en) * | 2004-01-22 | 2005-08-04 | Murata Mfg Co Ltd | Film forming method |
| US6989723B2 (en) | 2002-12-11 | 2006-01-24 | Tdk Corporation | Piezoelectric resonant filter and duplexer |
| US7113055B2 (en) | 2003-11-07 | 2006-09-26 | Matsushita Electric Industrial Co., Ltd. | Piezoelectric resonator, method of manufacturing piezoelectric resonator, and filter, duplexer, and communication device using piezoelectric resonator |
| US7230367B2 (en) | 2003-11-07 | 2007-06-12 | Matsushita Electric Industrial Co., Ltd. | Piezoelectric resonator, production method thereof, filter, duplexer, and communication device |
| US7259498B2 (en) | 2003-09-17 | 2007-08-21 | Matsushita Electric Industrial Co., Ltd. | Piezoelectric resonator, filter, and duplexer |
| US7446455B2 (en) | 2004-12-07 | 2008-11-04 | Matsushita Electric Industrial Co., Ltd. | Thin film elastic wave resonator |
| US7504910B2 (en) | 2004-04-30 | 2009-03-17 | Murata Manufacturing Co., Ltd. | Thin-film piezoelectric resonator utilizing a second or higher harmonic mode |
| US7531943B2 (en) | 2004-03-31 | 2009-05-12 | Panasonic Corporation | Acoustic resonator and filter |
| US7623007B2 (en) | 2005-10-19 | 2009-11-24 | Panasonic Corporation | Device including piezoelectric thin film and a support having a vertical cross-section with a curvature |
| US7667558B2 (en) | 2004-12-07 | 2010-02-23 | Panasonic Corporation | Thin film elastic wave resonator |
| US7701117B2 (en) | 2005-06-30 | 2010-04-20 | Panasonic Corporation | Acoustic resonator and filter |
| US20140191825A1 (en) * | 2013-01-09 | 2014-07-10 | Samsung Electronics Co., Ltd. | Radio frequency filter and manufacturing method thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4928795A (en) * | 1972-07-14 | 1974-03-14 | ||
| JPS5829211A (en) * | 1981-08-13 | 1983-02-21 | Nec Corp | Thin film piezoelectric oscillator |
| JPS58137318A (en) * | 1982-02-10 | 1983-08-15 | Nec Corp | Thin-film piezoelectric oscillator |
-
1983
- 1983-09-26 JP JP17626983A patent/JPS6068711A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4928795A (en) * | 1972-07-14 | 1974-03-14 | ||
| JPS5829211A (en) * | 1981-08-13 | 1983-02-21 | Nec Corp | Thin film piezoelectric oscillator |
| JPS58137318A (en) * | 1982-02-10 | 1983-08-15 | Nec Corp | Thin-film piezoelectric oscillator |
Cited By (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6382116A (en) * | 1986-09-26 | 1988-04-12 | Matsushita Electric Ind Co Ltd | Piezoelectric thin film resonator and its manufacture |
| JP2001203558A (en) * | 1999-11-11 | 2001-07-27 | Murata Mfg Co Ltd | Piezoelectric resonator, filter and electronic device |
| JP2001211053A (en) * | 1999-11-17 | 2001-08-03 | Murata Mfg Co Ltd | Piezoelectric resonator, electronic component and electronic apparatus |
| US6989723B2 (en) | 2002-12-11 | 2006-01-24 | Tdk Corporation | Piezoelectric resonant filter and duplexer |
| US7259498B2 (en) | 2003-09-17 | 2007-08-21 | Matsushita Electric Industrial Co., Ltd. | Piezoelectric resonator, filter, and duplexer |
| USRE42009E1 (en) | 2003-09-17 | 2010-12-28 | Panasonic Corporation | Piezoelectric resonator having a spurious component control layer, filter using the piezoelectric resonator, and duplexer using the piezoelectric resonator |
| US7477115B2 (en) | 2003-11-07 | 2009-01-13 | Panasonic Corporation | Piezoelectric resonator, method of manufacturing piezoelectric resonator, and filter, duplexer, and communication device using piezoelectric resonator |
| US7230367B2 (en) | 2003-11-07 | 2007-06-12 | Matsushita Electric Industrial Co., Ltd. | Piezoelectric resonator, production method thereof, filter, duplexer, and communication device |
| US7113055B2 (en) | 2003-11-07 | 2006-09-26 | Matsushita Electric Industrial Co., Ltd. | Piezoelectric resonator, method of manufacturing piezoelectric resonator, and filter, duplexer, and communication device using piezoelectric resonator |
| JP4590871B2 (en) * | 2004-01-22 | 2010-12-01 | 株式会社村田製作所 | Method for forming piezoelectric element |
| JP2005209889A (en) * | 2004-01-22 | 2005-08-04 | Murata Mfg Co Ltd | Film forming method |
| US7531943B2 (en) | 2004-03-31 | 2009-05-12 | Panasonic Corporation | Acoustic resonator and filter |
| US7504910B2 (en) | 2004-04-30 | 2009-03-17 | Murata Manufacturing Co., Ltd. | Thin-film piezoelectric resonator utilizing a second or higher harmonic mode |
| US7446455B2 (en) | 2004-12-07 | 2008-11-04 | Matsushita Electric Industrial Co., Ltd. | Thin film elastic wave resonator |
| US7667558B2 (en) | 2004-12-07 | 2010-02-23 | Panasonic Corporation | Thin film elastic wave resonator |
| US7701117B2 (en) | 2005-06-30 | 2010-04-20 | Panasonic Corporation | Acoustic resonator and filter |
| US7623007B2 (en) | 2005-10-19 | 2009-11-24 | Panasonic Corporation | Device including piezoelectric thin film and a support having a vertical cross-section with a curvature |
| US20140191825A1 (en) * | 2013-01-09 | 2014-07-10 | Samsung Electronics Co., Ltd. | Radio frequency filter and manufacturing method thereof |
| US9954511B2 (en) * | 2013-01-09 | 2018-04-24 | Samsung Electronics Co., Ltd. | Radio frequency filter and manufacturing method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5446330A (en) | Surface acoustic wave device having a lamination structure | |
| JP3435789B2 (en) | Surface acoustic wave device | |
| US6239536B1 (en) | Encapsulated thin-film resonator and fabrication method | |
| CA1236182A (en) | Piezoelectric resonating device | |
| US4456850A (en) | Piezoelectric composite thin film resonator | |
| EP0797300B1 (en) | Piezoelectric vibrator and manufacturing method thereof | |
| JPS6068711A (en) | Piezoelectric thin film resonator | |
| US5910699A (en) | Method of manufacturing a composite substrate and a piezoelectric device using the substrate | |
| JP3703773B2 (en) | Manufacturing method of crystal unit | |
| JPH01157108A (en) | Piezoelectric thin film resonator | |
| US5647932A (en) | Method of processing a piezoelectric device | |
| JPH09130199A (en) | Piezoelectric thin film element and its production | |
| US4634913A (en) | Application of lithium tetraborate to electronic devices | |
| JPS6382116A (en) | Piezoelectric thin film resonator and its manufacture | |
| JPH0365046B2 (en) | ||
| JPH08153915A (en) | Composite piezoelectric substrate and its manufacture | |
| JPS62266906A (en) | Piezoelectric thin film resonator | |
| Eda et al. | Direct bonding of quartz crystal onto silicon | |
| JP2000165188A (en) | Piezoelectric resonator | |
| JP3493315B2 (en) | Piezoelectric resonator | |
| JPH0818115A (en) | Composite piezoelectric device | |
| JPS61127217A (en) | Piezoelectric thin film resonator | |
| Eda et al. | One-chip quartz crystal oscillator using a direct-bonding technique of quartz crystal onto silicon | |
| JP2003273691A (en) | Surface acoustic wave device | |
| JPH09221392A (en) | Composite piezoelectric substrate and its production |