JP2007243435A - Piezoelectric resonator chip and frequency adjustment method for same - Google Patents

Piezoelectric resonator chip and frequency adjustment method for same Download PDF

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JP2007243435A
JP2007243435A JP2006061247A JP2006061247A JP2007243435A JP 2007243435 A JP2007243435 A JP 2007243435A JP 2006061247 A JP2006061247 A JP 2006061247A JP 2006061247 A JP2006061247 A JP 2006061247A JP 2007243435 A JP2007243435 A JP 2007243435A
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adjustment
vibrating piece
frequency
leg
dry etching
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Satoshi Fujii
智 藤井
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Daishinku Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric resonator chip with high reliability capable of realizing high performance and high stability of the electric characteristics of a piezoelectric resonator by eliminating the effect of mask deviation in the case of executing frequency adjustment by means of dry etching, and to provide a frequency adjustment method for the piezoelectric resonator chip. <P>SOLUTION: The piezoelectric resonator chip comprises: a base part 20; and a plurality of legs 21, 22 projected from the base part, each leg is provided with frequency adjustment films 25, 26 formed to a tip of a leg principal side and exciting electrodes 23, 24 formed to the legs, and the type of material of the surface of the exciting electrodes has an elimination rate by the dry etching lower than that of the type of the material of the surface of the frequency adjustment films. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、基部と、この基部から突出された複数の脚部とからなる圧電振動片、および圧電振動片の周波数調整方法に係る。   The present invention relates to a piezoelectric vibrating piece including a base and a plurality of legs protruding from the base, and a frequency adjusting method for the piezoelectric vibrating piece.

従来の圧電振動片を、音叉型水晶振動片を例にして説明すると、例えば、水晶振動片が基部と、この基部から突出された２本の脚部とから構成される。そして、これら基部および脚部の外面に励振電極が形成され、各脚部主面の先端部には周波数調整用の調整電極（周波数調整膜）が形成されている。励振電極は、例えば、一方の脚部の表裏主面と他方の脚部の両側面に第１の励振電極が形成され、一方の脚部の両側面と他方の脚部の表裏主面に第２の励振電極が形成されている。つまり、一方の脚部表裏主面中央に第１の励振電極が形成され、前記第１の励振電極から離隔して脚部の稜に近接した側面に第２の励振電極が形成されるとともに、他方の脚部表裏主面中央に第２の励振電極が形成され、前記第２の励振電極から離隔して脚部の稜に近接した側面に第１の励振電極が形成されている。このような音叉型水晶振動片は、小型化に伴って、フォトリソグラフィ技術を用いて水晶ウェハを化学的エッチングすることにより、複数個の音叉型水晶振動片を作成している。   A conventional piezoelectric vibrating piece will be described by taking a tuning-fork type quartz vibrating piece as an example. For example, the quartz vibrating piece includes a base and two legs protruding from the base. Excitation electrodes are formed on the outer surfaces of the base and the leg, and an adjustment electrode (frequency adjustment film) for frequency adjustment is formed at the tip of each leg main surface. For example, the first excitation electrode is formed on the front and back main surfaces of one leg and both side surfaces of the other leg, and the excitation electrode is formed on both side surfaces of one leg and the front and back main surfaces of the other leg. Two excitation electrodes are formed. That is, a first excitation electrode is formed at the center of one leg front and back main surfaces, and a second excitation electrode is formed on a side surface that is spaced apart from the first excitation electrode and close to the ridge of the leg, A second excitation electrode is formed at the center of the front and back main surfaces of the other leg, and a first excitation electrode is formed on a side surface that is spaced apart from the second excitation electrode and close to the ridge of the leg. With such tuning fork type quartz crystal vibrating pieces, a plurality of tuning fork type quartz vibrating pieces are created by chemically etching a quartz wafer using a photolithographic technique with downsizing.

近年、このような圧電振動片の周波数調整手法として、粗調整工程と微調整工程で方法を異ならせることが多い。例えば、特許文献１に開示されているように、粗調整では調整電極の一部を完全に除去させることで調整幅のより高いレーザを用いる一方で、微調整工程ではマスク治具を用いて調整電極（周波数調整膜）を全体的に薄肉化させより調整幅が緩やかであるとともに、金属屑の発生が少ないミーリング等のドライエッチングを用いることがある。このように粗調整工程と微調整工程とで手法を変えることで、圧電振動子の電気的特性の高性能化や高安定化が実現できるものである。また、このような周波数調整のうち、粗調整はウェハ状態で実施し、微調整はウェハから取り出された個々の圧電振動片をパッケージに搭載した後に実施される。ウェハで全ての周波数調整（粗調整と微調整）を終えた後に、圧電振動片をパッケージに搭載すると、搭載時の応力であったり接着剤硬化の際の加熱処理等の外的要因によって、周波数変動が生じることがある。このため、微調整工程をパッケージ搭載後に実施することで、圧電振動片をパッケージ搭載することによる周波数変動の外的要因を排除することができるのでより好ましい。
特開２００３−３１８６８５号公報 In recent years, as a method of adjusting the frequency of such a piezoelectric vibrating piece, there are many cases where the method is different between the coarse adjustment step and the fine adjustment step. For example, as disclosed in Patent Document 1, a coarse adjustment uses a laser with a higher adjustment width by completely removing a part of the adjustment electrode, while a fine adjustment process uses a mask jig to make an adjustment. Dry etching such as milling or the like may be used in which the electrode (frequency adjustment film) is thinned as a whole and the adjustment range is more gradual and the generation of metal debris is less. Thus, by changing the method between the coarse adjustment step and the fine adjustment step, it is possible to realize high performance and high stability of the electrical characteristics of the piezoelectric vibrator. Of these frequency adjustments, coarse adjustment is performed in the wafer state, and fine adjustment is performed after the individual piezoelectric vibrating pieces taken out from the wafer are mounted on the package. When all the frequency adjustments (coarse adjustment and fine adjustment) have been completed on the wafer and the piezoelectric vibrating piece is mounted on the package, the frequency may be affected by external factors such as stress during mounting or heat treatment during curing of the adhesive. Variations may occur. For this reason, it is more preferable that the fine adjustment process is performed after the package is mounted because an external factor of frequency fluctuation caused by mounting the piezoelectric vibrating piece can be eliminated.
Japanese Patent Laid-Open No. 2003-318685

しかしながら、上述した圧電振動片では、周波数微調整工程におけるミーリング等のドライエッチング手法を実施する場合、圧電振動片とマスク部材の相互位置関係により、ドライエッチング領域のずれ込みが生じると言った問題があるが、近年開発が進んでいる超小型の圧電振動片にあっては、これらの問題が顕著に現れる。特に、マスク部材を用いたドライエッチング手法により周波数調整する場合、圧電振動片を搭載するパッケージ、パッケージを保持するホルダー、圧電振動片の調整電極部のみを開口させたマスク部材等の各構成要素を組み合わせて相互に位置決めしている。どころが、圧電振動片が小型化するに伴って、各構成要素での公差の影響が大きくなり、わずかなずれ込みによりマスクずれが生じてしまう。このため、調整電極からドライエッチング領域がずれ込み、所望の周波数調整が得られず、極めて周波数調整効率が悪くなるといった問題もあった。また、前記ドライエッチング領域がずれ込み、調整電極以外の励振電極領域まで達すると、直列共振抵抗値などの圧電振動子の電気的特性を低下させる原因となることもあった。   However, in the above-described piezoelectric vibrating piece, when dry etching techniques such as milling in the frequency fine adjustment process are performed, there is a problem that the dry etching region shifts due to the mutual positional relationship between the piezoelectric vibrating piece and the mask member. However, in the ultra-compact piezoelectric vibrating piece that has been developed in recent years, these problems appear remarkably. In particular, when the frequency is adjusted by a dry etching method using a mask member, each component such as a package on which the piezoelectric vibrating piece is mounted, a holder for holding the package, and a mask member in which only the adjustment electrode portion of the piezoelectric vibrating piece is opened is provided. They are combined and positioned with respect to each other. On the contrary, as the piezoelectric vibrating piece is reduced in size, the influence of tolerance on each component increases, and mask displacement occurs due to slight displacement. For this reason, the dry etching region is shifted from the adjustment electrode, so that the desired frequency adjustment cannot be obtained, and the frequency adjustment efficiency is extremely deteriorated. Further, when the dry etching region is shifted and reaches the excitation electrode region other than the adjustment electrode, the electrical characteristics of the piezoelectric vibrator such as the series resonance resistance value may be deteriorated.

本発明は、かかる点に鑑みてなされたものであり、その目的とするところは、ドライエッチングにより周波数調整する場合に、マスクずれの影響をなくし、圧電振動子の電気的特性の高性能化や高安定化が実現できるより信頼性の高い圧電振動片、および圧電振動片の周波数調整方法を提供することにある。   The present invention has been made in view of such points, and the object of the present invention is to eliminate the influence of mask displacement when adjusting the frequency by dry etching, and to improve the electrical characteristics of the piezoelectric vibrator. It is an object of the present invention to provide a more reliable piezoelectric vibrating piece capable of achieving high stabilization and a frequency adjusting method for the piezoelectric vibrating piece.

前記の目的を達成するため、本発明の特許請求項１に係る圧電振動片では、基部と、この基部から突出された複数の脚部とからなり、各脚部には、脚部主面の先端部に形成された周波数調整膜と、脚部に形成された励振電極とを具備しており、前記周波数調整膜の表面材質に対して前記励振電極の表面材質の方がドライエッチングによる除去レートの低い材料で形成されてなることを特徴とする。   In order to achieve the above object, a piezoelectric vibrating piece according to claim 1 of the present invention includes a base portion and a plurality of leg portions protruding from the base portion, and each leg portion has a leg main surface. A frequency adjusting film formed on a tip portion and an excitation electrode formed on a leg portion, and the surface material of the excitation electrode is removed by dry etching with respect to the surface material of the frequency adjusting film; It is characterized by being formed of a low material.

本発明の特許請求項１によれば、前記周波数調整膜の表面材質に対して前記励振電極の表面材質の方がドライエッチングによる除去レートの低い材料で形成されているので、励振電極に比べて周波数調整膜の方が極めて除去レートの高い状態でドライエッチングされ、励振電極を不要に除去することがない圧電振動片が得られる。結果として、直列共振抵抗値などの圧電振動子の電気的特性を低下させることが一切なくなる。また、圧電振動片とマスク部材の公差に余裕を持たせることができ、マスクずれの悪影響を軽減することができ、調整電極からドライエッチング領域がずれ込むことによって周波数調整効率を低下させることもなくなる。   According to the first aspect of the present invention, the surface material of the excitation electrode is formed of a material having a lower removal rate by dry etching than the surface material of the frequency adjustment film, so that it is compared with the excitation electrode. The frequency adjustment film is dry-etched with a much higher removal rate, and a piezoelectric vibrating piece that does not unnecessarily remove the excitation electrode is obtained. As a result, the electrical characteristics of the piezoelectric vibrator such as the series resonance resistance value are not deteriorated at all. Further, the tolerance of the piezoelectric vibrating piece and the mask member can be given a margin, the adverse effect of the mask displacement can be reduced, and the frequency adjustment efficiency is not lowered due to the dry etching region being displaced from the adjustment electrode.

また、本発明の特許請求項２に係る圧電振動片では、基部と、この基部から突出された複数の脚部とからなり、各脚部には、脚部主面の先端部に形成された周波数調整膜と、脚部に形成された励振電極と、当該励振電極の少なくとも上面に形成された表面膜を具備しており、前記周波数調整膜の表面材質に対して前記表面膜の表面材質の方がドライエッチングによる除去レートの低い材料で形成されてなることを特徴とする。   The piezoelectric vibrating piece according to claim 2 of the present invention includes a base portion and a plurality of leg portions protruding from the base portion, and each leg portion is formed at a tip portion of the leg main surface. A frequency adjustment film, an excitation electrode formed on the leg, and a surface film formed on at least the upper surface of the excitation electrode, the surface material of the surface film being different from the surface material of the frequency adjustment film. This is characterized in that it is formed of a material having a low removal rate by dry etching.

本発明の特許請求項２によれば、前記周波数調整膜の表面材質に対して前記表面層の表面材質の方がドライエッチングによる除去レートの低い材料で形成されているので、表面膜に比べて周波数調整膜の方が極めて除去レートの高い状態でドライエッチングされ、励振電極を不要に除去することがない圧電振動片が得られる。結果として、直列共振抵抗値などの圧電振動子の電気的特性を低下させることが一切なくなる。また、圧電振動片とマスク部材の公差に余裕を持たせることができ、マスクずれの悪影響を軽減することができ、調整電極からドライエッチング領域がずれ込むことによって周波数調整効率を低下させることもなくなる。   According to claim 2 of the present invention, the surface material of the surface layer is formed of a material having a lower removal rate by dry etching than the surface material of the frequency adjusting film, so that it is compared with the surface film. The frequency adjustment film is dry-etched with a much higher removal rate, and a piezoelectric vibrating piece that does not unnecessarily remove the excitation electrode is obtained. As a result, the electrical characteristics of the piezoelectric vibrator such as the series resonance resistance value are not deteriorated at all. Further, the tolerance of the piezoelectric vibrating piece and the mask member can be given a margin, the adverse effect of the mask displacement can be reduced, and the frequency adjustment efficiency is not lowered due to the dry etching region being displaced from the adjustment electrode.

また、本発明の特許請求項３に係る圧電振動片の周波数調整方法では、上述の圧電振動片において、ドライエッチングにより前記周波数調整膜の質量を除去することで周波数調整してなることを特徴とする。   According to a third aspect of the present invention, there is provided a method of adjusting a frequency of a piezoelectric vibrating piece, wherein the frequency of the piezoelectric vibrating piece is adjusted by removing the mass of the frequency adjusting film by dry etching. To do.

本発明によれば、上述の圧電振動片と同様に、励振電極を不要に除去することがない圧電振動片の周波数調整方法が得られる。結果として、上記本発明の圧電振動片と同様に、直列共振抵抗値などの圧電振動子の電気的特性を低下させることが一切なくなる。また、圧電振動片とマスク部材の公差に余裕を持たせることができ、マスクずれの悪影響を軽減することができ、調整電極からドライエッチング領域がずれ込むことによって周波数調整効率を低下させることもなくなる。   According to the present invention, similarly to the above-described piezoelectric vibrating piece, a method of adjusting the frequency of the piezoelectric vibrating piece that does not unnecessarily remove the excitation electrode can be obtained. As a result, the electrical characteristics of the piezoelectric vibrator such as the series resonance resistance value are not deteriorated at all as in the piezoelectric vibrating piece of the present invention. Further, the tolerance of the piezoelectric vibrating piece and the mask member can be given a margin, the adverse effect of the mask displacement can be reduced, and the frequency adjustment efficiency is not lowered due to the dry etching region being displaced from the adjustment electrode.

本発明によれば、ドライエッチングにより周波数調整する場合に、マスクずれの影響をなくし、圧電振動子の電気的特性の高性能化や高安定化が実現できるより信頼性の高い圧電振動片、および圧電振動片の周波数調整方法を提供することができる。   According to the present invention, when the frequency is adjusted by dry etching, the influence of the mask displacement is eliminated, and a more reliable piezoelectric vibrating piece capable of realizing high performance and high stability of the electrical characteristics of the piezoelectric vibrator, and A method of adjusting the frequency of the piezoelectric vibrating piece can be provided.

以下、本発明の実施の形態について図面を参照して説明する。なお、以下に示す実施の形態では、圧電振動片として音叉型水晶振動片に本発明を適用した場合を示す。図１は本形態に係る水晶ウェハ１を示す平面図であり、図２は本形態に係る音叉型水晶振動片２を模式的に示したもので、励振電極２３，２４の配設状態を示す斜視図である。また、図３は図２のＡ−Ａ線に沿った断面図であり、図４は図２のＢ−Ｂ線に沿った断面図である。図５は図２のＣ−Ｃ線に沿った断面図である。   Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiment, a case where the present invention is applied to a tuning fork type crystal vibrating piece as a piezoelectric vibrating piece is shown. FIG. 1 is a plan view showing a crystal wafer 1 according to the present embodiment, and FIG. 2 schematically shows a tuning fork type crystal vibrating piece 2 according to the present embodiment, and shows the arrangement of excitation electrodes 23 and 24. It is a perspective view. 3 is a cross-sectional view taken along line AA in FIG. 2, and FIG. 4 is a cross-sectional view taken along line BB in FIG. FIG. 5 is a sectional view taken along the line CC of FIG.

音叉型水晶振動片２は、図１に示すように、１枚のウェハ１から、フォトリソグラフィ等の工法により、複数個を得るようにし、各水晶振動片を切り離す前に、励振電極等が形成される。   As shown in FIG. 1, a tuning fork type crystal vibrating piece 2 is obtained by a method such as photolithography from a single wafer 1, and an excitation electrode or the like is formed before separating each crystal vibrating piece. Is done.

音叉型水晶振動片２は、基部２０と、この基部から突出された２本の脚部２１，２２を備えており、その脚部の主面（表裏面）に溝部２１１，２２１が形成されている。ここでいう溝部は、貫通孔であってもよく、窪み部であってもよい。これら基部および脚部の外面には、第１及び第２の励振電極２３，２４が形成され、各脚部主面の先端部には電極の質量が増減されることで周波数が調整されてなる調整電極２５，２６（周波数調整膜）が形成されている。前記励振電極２３，２４は、脚部２１の表裏主面と脚部２２の稜に近接する部分に第１の励振電極２３が形成され、脚部２１の稜に近接する部分と脚部２２の表裏主面に第２の励振電極２４が形成されている。   The tuning fork type crystal vibrating piece 2 includes a base portion 20 and two leg portions 21 and 22 protruding from the base portion, and groove portions 211 and 221 are formed on the main surfaces (front and back surfaces) of the leg portions. Yes. The groove part here may be a through hole or a hollow part. First and second excitation electrodes 23 and 24 are formed on the outer surfaces of the base and the leg, and the frequency is adjusted by increasing or decreasing the mass of the electrode at the tip of each leg main surface. Adjustment electrodes 25 and 26 (frequency adjustment films) are formed. The first excitation electrodes 23 are formed on the front and back main surfaces of the leg portion 21 and the ridges of the leg portions 22, and the excitation electrodes 23 and 24 are formed on the leg portions 22. Second excitation electrodes 24 are formed on the front and back main surfaces.

つまり、脚部２１には、先端部に調整電極２５（周波数調整膜）が形成され、当該調整電極２５から第１の無電極部２１２を介して表裏主面中央に主面中央励振電２３１が形成され、当該主面中央励振電極２３１から第２の無電極部２１３を介して脚部の稜に近接して形成される端部励振電極２４２が形成されている。脚部２２には、先端部に調整電極２６（周波数調整膜）が形成され、当該調整電極２６から第１の無電極部２２２を介して表裏主面中央に主面中央励振電２４１が形成され、当該主面中央励振電極２４１から第２の無電極部２２３を介して脚部の稜に近接して形成される端部励振電極２３２が形成されている。   That is, an adjustment electrode 25 (frequency adjustment film) is formed at the tip of the leg 21, and a main surface central excitation 231 is provided from the adjustment electrode 25 to the center of the front and back main surfaces via the first electrodeless portion 212. An end excitation electrode 242 is formed which is formed in the vicinity of the ridge of the leg portion from the main surface central excitation electrode 231 via the second electrodeless portion 213. An adjustment electrode 26 (frequency adjustment film) is formed at the tip of the leg 22, and a main surface central excitation 241 is formed from the adjustment electrode 26 to the center of the front and back main surfaces via the first electrodeless portion 222. An end excitation electrode 232 is formed from the main surface central excitation electrode 241 through the second non-electrode portion 223 and close to the ridge of the leg portion.

これら励振電極２３，２４は、金属蒸着によって形成されたクロム（Ｃｒ）の上層に金（Ａｕ）、その上部にさらにクロム（Ｃｒ）の薄膜がフォトリソグラフィ等の工法により形成されている。当該励振電極２３，２４では、最上面に形成されたクロム（Ｃｒ）の層が表面膜を構成している。調整電極２５，２６は、前記励振電極と同様にクロム（Ｃｒ）の上層に金（Ａｕ）等の薄膜がフォトリソグラフィ等の工法により形成され、その上部にさらに銀（Ａｇ）等が蒸着マスクを用いた金属蒸着あるいはスパッタリング等によって形成された薄膜となっている。   In the excitation electrodes 23 and 24, gold (Au) is formed on an upper layer of chromium (Cr) formed by metal vapor deposition, and a thin film of chromium (Cr) is further formed thereon by a method such as photolithography. In the excitation electrodes 23 and 24, a chromium (Cr) layer formed on the uppermost surface constitutes a surface film. As with the excitation electrodes, the adjustment electrodes 25 and 26 are formed by forming a thin film of gold (Au) or the like on the upper layer of chromium (Cr) by a method such as photolithography, and silver (Ag) or the like is further deposited on the vapor deposition mask. It is a thin film formed by metal deposition or sputtering used.

この調整電極２５，２６に対して、例えば同様の銀（Ａｇ）を付加することや、その一部が、ビーム照射あるいはミーリング等によって除去されることで、音叉型水晶振動片２の発振周波数を調整することができる。このとき、調整電極２５，２６は、電極付加を中心に周波数調整する場合、周波数調整前の振動子の発振周波数が目標周波数よりも高くなるように形成され、電極除去を中心に周波数調整する場合、周波数調整前の振動子１の発振周波数が目標周波数よりも低くなるように形成されている。   For example, similar silver (Ag) is added to the adjustment electrodes 25 and 26, or a part of the adjustment electrodes 25 and 26 is removed by beam irradiation or milling, so that the oscillation frequency of the tuning-fork type crystal vibrating piece 2 can be reduced. Can be adjusted. At this time, the adjustment electrodes 25 and 26 are formed so that the oscillation frequency of the vibrator before the frequency adjustment is higher than the target frequency when frequency adjustment is performed centering on electrode addition, and the frequency adjustment is performed centering on electrode removal. The oscillation frequency of the vibrator 1 before frequency adjustment is formed to be lower than the target frequency.

本発明の形態では、より精度の高く高率的な周波数調整を実施するために、調整電極２５，２６に対して、金属蒸着などにより同様の銀（Ａｇ）を付加することや、レーザービーム照射により一部を完全に除去することで調整幅のより高い周波数粗調整を実施している。その後、同じ調整電極２５，２６に対して、図示しないマスク治具を用いてミーリング等のドライエッチング手法により調整電極を全体的に薄肉化することでより調整幅の緩やであるとともに金属屑の発生が少ない周波数微調整を実施している。ミーリング等のドライエッチング手法により調整電極２５，２６を除去して周波数を高める微調整を実施する場合、前記調整電極である銀材料に最適な除去レート時間に対応したドライエッチングの出力設定をしている。例えば、銀材料では、０．０１５〜０．０５μｍ/sec程度で除去されるようにミーリング装置の出力を設定した。この出力設定は、調整電極（周波数調整膜）の材料に応じて最適な値に設定する必要がある。   In the embodiment of the present invention, the same silver (Ag) is added to the adjustment electrodes 25 and 26 by metal vapor deposition or laser beam irradiation in order to carry out frequency adjustment with higher accuracy and higher efficiency. Thus, the frequency coarse adjustment with a higher adjustment range is carried out by completely removing a part. Thereafter, the adjustment electrode is made thinner overall by a dry etching technique such as milling using a mask jig (not shown) with respect to the same adjustment electrode 25, 26, and the adjustment width is further reduced and the metal debris is reduced. Frequency fine adjustment is performed with little occurrence. When fine adjustment is performed to increase the frequency by removing the adjustment electrodes 25 and 26 by a dry etching technique such as milling, the output of dry etching is set corresponding to the optimum removal rate time for the silver material as the adjustment electrode. Yes. For example, with a silver material, the output of the milling device was set so that it was removed at about 0.015 to 0.05 μm / sec. This output setting needs to be set to an optimum value according to the material of the adjustment electrode (frequency adjustment film).

このように、本発明の実施形態では、前記調整電極２５，２６の表面材質の銀（Ａｇ）に対して、前記励振電極２３，２４の表面膜であるクロム（Ｃｒ）の表面材質の方がドライエッチングによる除去レートの低い材料で形成されており、前記調整電極（周波数調整膜）である銀の除去レート時間に対応したドライエッチングの出力設定をしながら、ドライエッチングにより調整電極２５，２６の質量を除去することで周波数調整している。このため、表面膜がクロムからなる励振電極２３，２４に比べて最上表面層が銀からなる調整電極２５，２６の方が極めて除去レートの高い状態でミーリング等のドライエッチングがなされ、励振電極２３，２４を不要に除去することがない。結果として、直列共振抵抗値などの音叉型水晶振動子の電気的特性を低下させることが一切なくなる。また、音叉型水晶振動片とマスク部材の公差に余裕を持たせることができ、マスクずれの悪影響を軽減することができ、調整電極２５，２６からミーリング等のドライエッチング領域がずれ込むことによって周波数調整効率を低下させることもなくなる。   As described above, in the embodiment of the present invention, the surface material of chromium (Cr), which is the surface film of the excitation electrodes 23 and 24, is more preferable than the surface material silver (Ag) of the adjustment electrodes 25 and 26. It is made of a material having a low removal rate by dry etching, and the output of the dry etching corresponding to the removal rate time of silver as the adjustment electrode (frequency adjustment film) is set while the adjustment electrodes 25 and 26 are formed by dry etching. The frequency is adjusted by removing the mass. Therefore, dry etching such as milling is performed with the adjustment electrodes 25 and 26 whose uppermost surface layer is made of silver being at a higher removal rate than the excitation electrodes 23 and 24 whose surface film is made of chromium, and the excitation electrode 23 is made. 24 are not removed unnecessarily. As a result, the electrical characteristics of the tuning fork type crystal resonator such as the series resonance resistance value are not deteriorated at all. Further, the tolerance of the tuning fork type crystal vibrating piece and the mask member can be provided with a margin, the adverse effect of the mask displacement can be reduced, and the frequency adjustment is performed by shifting the dry etching region such as milling from the adjustment electrodes 25 and 26. The efficiency is not reduced.

なお、本形態の実施形態では、調整電極２５，２６（周波数調整膜）は、最上部が銀（Ａｇ）により形成されているが、金（Ａｕ）などでもよい。周波数調整膜としては、膜形成の容易性から金属からなる電極材料がより好ましいが、比重が高く、ミーリング等のドライエッチングによる除去レートが高いものであれば金属材料以外のものであってもよく、本形態のように多層構造の周波数調整膜に限らず単層構造の周波数調整膜であってもよい。   In the embodiment of the present embodiment, the uppermost portions of the adjustment electrodes 25 and 26 (frequency adjustment films) are made of silver (Ag), but may be gold (Au) or the like. As the frequency adjusting film, an electrode material made of a metal is more preferable because of the ease of film formation, but a material other than a metal material may be used as long as it has a high specific gravity and a high removal rate by dry etching such as milling. As in the present embodiment, the frequency adjustment film is not limited to the multilayer structure, and may be a single layer structure.

また、励振電極２３，２４は、クロム（Ｃｒ）の上層に金（Ａｕ）、その上部の表面膜として、クロム（Ｃｒ）を形成したものを例にしているが、ドライエッチングによる除去レートが周波数調整膜に対して十分に低いものを励振電極の表面膜として選択すればよい。例えば、ニッケル（Ｎｉ）等の金属膜、あるいは、酸化クロムや酸化ニッケル、ＳｉＯ2、ＳｉＯ等の絶縁膜でもよい。金属膜の場合、励振電極と同様に膜形成できるので比較的容易に作成できる利点がある。絶縁膜の場合、図６に示すように、異極の励振電極間にまたがって形成することができるので、脚部全面に形成することで短絡防止の用の保護膜とすることができる。 The excitation electrodes 23 and 24 are exemplified by gold (Au) formed on the upper layer of chromium (Cr) and chromium (Cr) as the upper surface film, but the removal rate by dry etching is a frequency. What is sufficient is just to select the surface film of the excitation electrode that is sufficiently lower than the adjustment film. For example, a metal film such as nickel (Ni) or an insulating film such as chromium oxide, nickel oxide, SiO 2 , or SiO may be used. In the case of a metal film, since the film can be formed in the same manner as the excitation electrode, there is an advantage that it can be formed relatively easily. In the case of the insulating film, as shown in FIG. 6, it can be formed across the excitation electrodes of different polarities, so that it can be formed as a protective film for preventing a short circuit by being formed over the entire leg portion.

図６は、上記実施形態の変形例を示す模式的な斜視図である（上記形態と同様の部分は同番号を付している）。この音叉型水晶振動片２では、前記調整電極２５，２６を除く、第１の無電極部２１２，２２２と、前記主面中央励振電極２３１，２４１と、前記第２の無電極部２１３，２２３の上部で、音叉型水晶振動片の表裏主面部分と両側面部分にＳｉＯ2（酸化珪素）からなる絶縁膜３が蒸着あるいはスパッタリング等の工法により形成されている。ここで蒸着される絶縁膜３の膜厚は、約０．００５〜０．０３μｍ均一に形成することが好ましい。これにより、異極の励振電極である主面中央励振電極２３１，２４１と端部励振電極２３２，２４２の間でゴミ等の異物が付着したとしても絶縁性を確実に確保することができ、音叉方水晶振動片の振動を阻害してＣＩ値特性が低下することがなくなる。また、図６に示すように、前記調整電極を除く脚部のほぼ全面に絶縁膜３を形成すれば、圧電振動片をパッケージに搭載する前の単体の状態あるいはウェハ状態でドライエッチングする場合、ドライエッチングの出力状態に応じて、マスク部材なしで周波数調整することもできる。 FIG. 6 is a schematic perspective view showing a modified example of the above embodiment (the same parts as those in the above embodiment are given the same numbers). In the tuning-fork type crystal vibrating piece 2, the first electrodeless portions 212 and 222, the main surface central excitation electrodes 231 and 241, and the second electrodeless portions 213 and 223, excluding the adjustment electrodes 25 and 26. The insulating film 3 made of SiO 2 (silicon oxide) is formed on the front and back main surface portions and both side surface portions of the tuning fork type quartz vibrating piece by a method such as vapor deposition or sputtering. The thickness of the insulating film 3 deposited here is preferably about 0.005 to 0.03 μm. As a result, even if foreign matter such as dust adheres between the main surface central excitation electrodes 231 and 241 and the end excitation electrodes 232 and 242, which are different polarity excitation electrodes, insulation can be reliably ensured, and the tuning fork The CI value characteristic is not deteriorated by inhibiting the vibration of the quartz crystal vibrating piece. Further, as shown in FIG. 6, when the insulating film 3 is formed on almost the entire surface of the legs excluding the adjustment electrode, when the piezoelectric vibrating piece is dry-etched in a single state or in a wafer state before being mounted on the package, Depending on the output state of the dry etching, the frequency can be adjusted without a mask member.

また、励振電極２３，２４は、本形態のように多層構造としなくてもよく、図７に示すように、除去レートが十分に低い電極材料（クロム単層やニッケル単層等）を単層構造で形成したものであってもよい。図７は、上記実施形態の変形例を示す模式的な断面図である（上記形態と同様の部分は同番号を付している）。この音叉型水晶振動片２では、前記銀（Ａｇ）等からなる調整電極２５，２６（周波数調整膜）の表面材質に対して、前記励振電極２３，２４の表面材質の方がドライエッチングによる除去レートの低い材料、例えば、クロム（Ｃｒ）やニッケル（Ｎｉ）等の単層電極としている。ここで形成される励振電極の厚みは、約０．００５〜０．０３μｍ程度で形成することが好ましい。これにより、クロムやニッケル等の膜応力など悪影響が生じることなく、励振電極２３，２４に比べて調整電極２５，２６（周波数調整膜）の方が極めて除去レートの高い状態でドライエッチングされ、励振電極２３，２４を不要に除去することがない。   Further, the excitation electrodes 23 and 24 do not have to have a multilayer structure as in this embodiment, and as shown in FIG. 7, a single layer of an electrode material (such as a chromium single layer or a nickel single layer) having a sufficiently low removal rate. It may be formed with a structure. FIG. 7 is a schematic cross-sectional view showing a modified example of the above embodiment (the same parts as those in the above embodiment are given the same numbers). In this tuning fork type crystal vibrating piece 2, the surface material of the excitation electrodes 23 and 24 is removed by dry etching with respect to the surface material of the adjustment electrodes 25 and 26 (frequency adjustment film) made of silver (Ag) or the like. A low-rate material, for example, a single layer electrode such as chromium (Cr) or nickel (Ni) is used. The thickness of the excitation electrode formed here is preferably about 0.005 to 0.03 μm. As a result, the adjustment electrodes 25 and 26 (frequency adjustment films) are dry-etched with a higher removal rate than the excitation electrodes 23 and 24 without adverse effects such as film stresses of chromium, nickel, etc., and excitation is performed. The electrodes 23 and 24 are not removed unnecessarily.

以上のような音叉型水晶振動片１は、例えば、パッケージ基体（図示省略）とキャップ（図示省略）とを接合することによりその内部に気密状態の空間が形成されたパッケージ（図示省略）内部に搭載されて、音叉型水晶振動子（図示省略）が構成される。   The tuning fork type crystal vibrating piece 1 as described above is formed inside a package (not shown) in which, for example, a package base (not shown) and a cap (not shown) are joined to form an airtight space therein. A tuning fork crystal resonator (not shown) is configured.

なお、上記実施形態では、圧電振動片として音叉型水晶振動片を適用した場合を示しているが、ＡＴカット水晶振動片やＧＴカット水晶振動片、あるいは水晶振動片に限らずセラミック振動片など他の圧電振動片を用いた圧電振動子にも適用できる。ドライエッチングとして、ミーリングを例にしたが、プラズマエッチング法や、反応性ガスイオンを用いたドライエッチング等であってもよい。   In the above embodiment, a tuning fork type crystal vibrating piece is applied as the piezoelectric vibrating piece. However, the present invention is not limited to the AT-cut quartz vibrating piece, the GT-cut quartz vibrating piece, the crystal vibrating piece, and other ceramic vibrating pieces. The present invention can also be applied to a piezoelectric vibrator using the piezoelectric vibrating piece. As an example of dry etching, milling is used as an example. However, plasma etching, dry etching using reactive gas ions, or the like may be used.

本発明は、その精神または主要な特徴から逸脱することなく、他のいろいろな形で実施できるので、限定的に解釈してはならない。本発明の範囲は特許請求範囲によって示すものであって、明細書本文に拘束されるものではない。さらに、特許請求の範囲の均等範囲に属する変形や変更は、全て本発明の範囲内のものである。   The present invention can be implemented in various other forms without departing from the spirit or main features thereof, and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not limited by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

本形態に係る水晶ウェハを示す平面図。The top view which shows the crystal wafer which concerns on this form. 図１の水晶ウェハの１つの音叉型水晶振動片を模式的に示した斜視図。FIG. 2 is a perspective view schematically showing one tuning fork type crystal vibrating piece of the crystal wafer of FIG. 1. 図２のＡ−Ａ線に沿った断面図。Sectional drawing along the AA line of FIG. 図２のＢ−Ｂ線に沿った断面図。Sectional drawing along the BB line of FIG. 図２のＣ−Ｃ線に沿った断面図。Sectional drawing along CC line of FIG. 本形態の変形例を示す模式的な斜視図。The typical perspective view which shows the modification of this form. 本形態の変形例を示す模式的な断面図。The typical sectional view showing the modification of this form.

符号の説明Explanation of symbols

１ 水晶ウェハ
２ 音叉型水晶振動片（圧電振動片）
1 Quartz wafer 2 Tuning fork type crystal vibrating piece (piezoelectric vibrating piece)

Claims (3)

基部と、この基部から突出された複数の脚部とからなる圧電振動片において、
各脚部には、
脚部主面の先端部に形成された周波数調整膜と、脚部に形成された励振電極とを具備しており、
前記周波数調整膜の表面材質に対して前記励振電極の表面材質の方がドライエッチングによる除去レートの低い材料で形成されてなることを特徴とする圧電振動片。 In a piezoelectric vibrating piece comprising a base and a plurality of legs protruding from the base,
Each leg has
A frequency adjusting film formed on the tip of the leg main surface, and an excitation electrode formed on the leg;
The piezoelectric vibrating piece according to claim 1, wherein the surface material of the excitation electrode is formed of a material having a lower removal rate by dry etching than the surface material of the frequency adjusting film. 基部と、この基部から突出された複数の脚部とからなる圧電振動片において、
各脚部には、
脚部主面の先端部に形成された周波数調整膜と、脚部に形成された励振電極と、当該励振電極の少なくとも上面に形成された表面膜を具備しており、
前記周波数調整膜の表面材質に対して前記表面膜の表面材質の方がドライエッチングによる除去レートの低い材料で形成されてなることを特徴とする圧電振動片。 In a piezoelectric vibrating piece comprising a base and a plurality of legs protruding from the base,
Each leg has
A frequency adjusting film formed on the tip of the leg main surface, an excitation electrode formed on the leg, and a surface film formed on at least the upper surface of the excitation electrode;
The piezoelectric vibrating piece according to claim 1, wherein the surface material of the surface film is formed of a material having a lower removal rate by dry etching than the surface material of the frequency adjusting film. 特許請求項１、または特許請求項２記載の圧電振動片において、ドライエッチングにより前記周波数調整膜の質量を除去することで周波数調整してなることを特徴とする圧電振動片の周波数調整方法。
3. The piezoelectric vibrating piece according to claim 1, wherein the frequency is adjusted by removing the mass of the frequency adjusting film by dry etching.
JP2006061247A 2006-03-07 2006-03-07 Piezoelectric resonator chip and frequency adjustment method for same Pending JP2007243435A (en)

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JP2009130445A (en) * 2007-11-20 2009-06-11 Citizen Holdings Co Ltd Vibrator and method for manufacturing vibrator
JP2010135973A (en) * 2008-12-03 2010-06-17 Nippon Dempa Kogyo Co Ltd Method for manufacturing piezoelectric device
JP2010200334A (en) * 2010-03-26 2010-09-09 Epson Toyocom Corp Piezoelectric vibration reed, piezoelectric vibrator, and acceleration sensor
JP2011030095A (en) * 2009-07-28 2011-02-10 Seiko Instruments Inc Piezoelectric vibrator, method for manufacturing piezoelectric vibrator, oscillator, electronic equipment, and radio wave clock
JP2012217140A (en) * 2011-03-29 2012-11-08 Nippon Dempa Kogyo Co Ltd Tuning-fork type piezoelectric vibration piece and piezoelectric device
JP2013138285A (en) * 2011-12-28 2013-07-11 Daishinku Corp Tuning-fork type crystal vibration piece, tuning-fork type crystal oscillator using the same and manufacturing method thereof
JP2016139899A (en) * 2015-01-27 2016-08-04 京セラクリスタルデバイス株式会社 Crystal device and manufacturing method of the same
CN107104652A (en) * 2016-02-23 2017-08-29 精工电子水晶科技股份有限公司 Piezoelectric vibration piece and piezoelectric vibrator

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JP2003060470A (en) * 2001-08-14 2003-02-28 Seiko Epson Corp Piezoelectric device, frequency-adjusting method for piezoelectric device, portable telephone device utilizing the piezoelectric device and electronic equipment utilizing the piezoelectric device
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JPS631206A (en) * 1986-06-20 1988-01-06 Matsushima Kogyo Co Ltd Piezoelectric vibration bar
JPH11145758A (en) * 1997-11-06 1999-05-28 Seiko Epson Corp Piezoelectric element and its production
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JP2000223998A (en) * 1999-01-29 2000-08-11 Seiko Instruments Inc Piezoelectric vibrator and manufacture therefor
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009130445A (en) * 2007-11-20 2009-06-11 Citizen Holdings Co Ltd Vibrator and method for manufacturing vibrator
JP2010135973A (en) * 2008-12-03 2010-06-17 Nippon Dempa Kogyo Co Ltd Method for manufacturing piezoelectric device
JP2011030095A (en) * 2009-07-28 2011-02-10 Seiko Instruments Inc Piezoelectric vibrator, method for manufacturing piezoelectric vibrator, oscillator, electronic equipment, and radio wave clock
JP2010200334A (en) * 2010-03-26 2010-09-09 Epson Toyocom Corp Piezoelectric vibration reed, piezoelectric vibrator, and acceleration sensor
JP2012217140A (en) * 2011-03-29 2012-11-08 Nippon Dempa Kogyo Co Ltd Tuning-fork type piezoelectric vibration piece and piezoelectric device
JP2013138285A (en) * 2011-12-28 2013-07-11 Daishinku Corp Tuning-fork type crystal vibration piece, tuning-fork type crystal oscillator using the same and manufacturing method thereof
JP2016139899A (en) * 2015-01-27 2016-08-04 京セラクリスタルデバイス株式会社 Crystal device and manufacturing method of the same
CN107104652A (en) * 2016-02-23 2017-08-29 精工电子水晶科技股份有限公司 Piezoelectric vibration piece and piezoelectric vibrator
CN107104652B (en) * 2016-02-23 2021-12-24 精工电子水晶科技股份有限公司 Piezoelectric vibrating piece and piezoelectric vibrator

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