WO2009157246A1 - Vibrating gyroscope using piezoelectric film and method for manufacturing the same - Google Patents

Vibrating gyroscope using piezoelectric film and method for manufacturing the same Download PDF

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Publication number
WO2009157246A1
WO2009157246A1 PCT/JP2009/057342 JP2009057342W WO2009157246A1 WO 2009157246 A1 WO2009157246 A1 WO 2009157246A1 JP 2009057342 W JP2009057342 W JP 2009057342W WO 2009157246 A1 WO2009157246 A1 WO 2009157246A1
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Prior art keywords
film
metal film
electrodes
piezoelectric
vibrating body
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PCT/JP2009/057342
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French (fr)
Japanese (ja)
Inventor
池田　隆志
荒木　隆太
伸貴 手嶋
泰之 平田
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住友精密工業株式会社
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Priority to JP2010517806A priority Critical patent/JP5209716B2/en
Publication of WO2009157246A1 publication Critical patent/WO2009157246A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
    • G01C19/56—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
    • G01C19/567—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces using the phase shift of a vibration node or antinode
    • G01C19/5677—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces using the phase shift of a vibration node or antinode of essentially two-dimensional vibrators, e.g. ring-shaped vibrators
    • G01C19/5684—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces using the phase shift of a vibration node or antinode of essentially two-dimensional vibrators, e.g. ring-shaped vibrators the devices involving a micromechanical structure

Definitions

  • the present invention relates to a vibration gyro using a piezoelectric film and a method for manufacturing the same.
  • the miniaturization of the gyro itself is also an important issue.
  • it is necessary to remarkably increase the processing accuracy of each member constituting the gyro.
  • it is a strong demand of the industry to provide a gyro with further improved angular velocity detection accuracy and a gyro that is resistant to unexpected vibration (disturbance).
  • the gyro structure shown in the following patent document does not satisfy the demand for miniaturization and high performance over the past several years.
  • the drive electrode that excites the primary vibration for the vibration gyro and the extraction electrode that is formed to capture the signal of the detection electrode that detects the secondary vibration caused by the angular velocity constitutes a piezoelectric element due to the manufacturing process. In some cases. In such a case, reducing the piezoelectric effect generated by the extraction electrode itself as much as possible is extremely useful for improving the detection accuracy as a vibration gyroscope.
  • the present invention greatly contributes to downsizing and high performance of a vibrating gyroscope using a piezoelectric film by solving the above technical problems.
  • the inventors have adopted an annular or polygonal vibration gyro as a basic structure, which is considered to have a relatively small influence on the disturbance.
  • the noise output generated by the formation of the extraction electrode described above is a relatively small output, but it is harmful to further improve the detection accuracy. I found out.
  • the present invention was created from such a viewpoint.
  • the “annular or polygonal vibration gyro” is simply referred to as “ring-shaped vibration gyro”.
  • One vibrating gyroscope of the present invention includes an annular or polygonal vibrating body, a leg portion that flexibly supports the vibrating body and has a fixed end, an upper metal film and a lower layer formed on the vibrating body.
  • a plurality of electrodes sandwiching the piezoelectric film in the thickness direction by the metal film and the leg portions, and the piezoelectric film and the low dielectric constant insulating film are formed by the upper metal film and the lower metal film.
  • “flexible” means “to the extent that the vibrating body can vibrate”.
  • the lead electrode is formed on the leg portion, and the piezoelectric film and the low dielectric constant insulating film are sandwiched between the upper metal film and the lower metal film in the thickness direction.
  • the piezoelectric effect, reverse piezoelectric effect, and capacitance on the leg portion can be greatly reduced. That is, since the piezoelectric film and the insulating film that also function as a capacitor are connected in series, for example, when a voltage is applied to the region, it is caused by a so-called reverse piezoelectric effect as compared with the case without the above-described insulator. Since the distortion of the piezoelectric body is greatly reduced, adverse effects on the primary vibration of the vibrating body can be reduced.
  • the capacitance obtained by synthesizing the piezoelectric film as the capacitor on the leg portion and the insulating film is significantly reduced as compared with the case where there is no insulator.
  • the above disturbance occurs, only weak polarization (surface charge) is generated in the piezoelectric film on the leg portion, and the piezoelectric effect is reduced. Is suppressed.
  • the intensity of the noise signal not caused by the disturbance is significantly reduced, so that the measurement accuracy of the angular velocity is improved.
  • One method of manufacturing a vibrating gyroscope according to the present invention is a method of manufacturing a vibrating gyroscope including a vibrating body and a leg portion that flexibly supports the vibrating body and has a fixed end. Specifically, a step of forming, by dry etching, a plurality of electrodes in which a piezoelectric film is sandwiched in the thickness direction between an upper metal film and a lower metal film above the above-described vibrating body having an annular shape or a polygonal shape.
  • a piezoelectric element that performs driving and detection is formed on the above-described vibrating body, and a reverse piezoelectric element is formed on the leg portion. It is possible to accurately form a piezoelectric element in which the effect and the piezoelectric effect are suppressed. That is, by forming the insulating film having a low dielectric constant accurately only at a predetermined position on the leg portion by the above-described manufacturing method, the piezoelectric effect, reverse piezoelectric effect, and capacitance on the leg portion are greatly reduced. be able to. As a result, it is possible to manufacture a vibrating gyroscope that does not cause unnecessary excitation of a vibrating body, is resistant to disturbances, and further significantly reduces the intensity of noise signals that do not depend on disturbances.
  • the reliability of the excited state of the primary vibration can be improved, and the angular velocity can be detected with high accuracy when the angular velocity occurs.
  • a piezoelectric element that performs driving and detection is formed on the above-described vibrating body by processing using a dry process technique, and a reverse is provided on the leg portion. It becomes possible to accurately form a piezoelectric element in which the piezoelectric effect and the piezoelectric effect are suppressed. As a result, it is possible to manufacture a vibrating gyroscope that does not cause unnecessary excitation of a vibrating body, is resistant to disturbance, and has a significantly reduced noise signal intensity that does not depend on the disturbance.
  • FIG. 2 is a cross-sectional view taken along the line AA in FIG. It is sectional drawing which shows the process of the one part manufacturing process of the ring-shaped vibrating gyroscope in one embodiment of this invention. It is sectional drawing which shows the process of the one part manufacturing process of the ring-shaped vibrating gyroscope in one embodiment of this invention. It is sectional drawing which shows the process of the one part manufacturing process of the ring-shaped vibrating gyroscope in one embodiment of this invention. It is sectional drawing which shows the process of the one part manufacturing process of the ring-shaped vibrating gyroscope in one embodiment of this invention.
  • FIG. 2 shows the structure of the manufacturing apparatus of the ring-shaped vibration gyroscope in one embodiment of this invention. It is sectional drawing equivalent to FIG. 2 in other embodiment of this invention. It is sectional drawing equivalent to FIG. 2 in other embodiment of this invention. It is a figure which illustrates notionally positive / negative of the electrical signal of a 1st detection electrode and a 2nd detection electrode. It is a figure explaining the vibrating body shape in other embodiment of this invention.
  • FIG. 1 is a front view of a structure that plays a central role in a ring-shaped vibrating gyroscope 100 according to this embodiment.
  • FIG. 2 is a cross-sectional view taken along the line AA in FIG.
  • the ring-shaped vibrating gyroscope 100 of this embodiment is roughly classified into three regions.
  • the first region is a region in which a plurality of films are stacked on an upper plane (hereinafter referred to as an upper surface) of the ring-shaped vibrating body 11 formed from the silicon substrate 10.
  • the plurality of electrodes 13a to 13d shown in FIG. 1 includes a first silicon oxide film 20 on an upper surface thereof, and a PZT film that is a piezoelectric film 40 is formed on platinum (Pt) that is a lower metal film 30. And a plurality of electrodes 13a to 13d formed by being sandwiched between platinum (Pt) as the upper metal film 60.
  • the upper metal film 60 constituting the plurality of electrodes 13a to 13d is formed about 1 ⁇ m inside from the outer peripheral edge of the ring-shaped vibrating body 11 having an upper surface with a width of about 46 ⁇ m, and the width is about 21 ⁇ m.
  • the upper metal film 60 of the ring-shaped vibrating body 11 is formed outside a line connecting the centers between both ends of the width of the upper surface of the ring-shaped vibrating body 11 (hereinafter simply referred to as a center line).
  • extraction electrodes 14,..., 14 are formed on the upper surface of the ring-shaped vibrating body 11 in order to apply a voltage to the plurality of electrodes 13 a to 13 d or acquire an electric signal.
  • the first silicon oxide film 20 is provided on the upper surface of the ring-shaped vibrating body 11, and the second silicon oxide film 50 and the piezoelectric film 40 as an insulating film having a low dielectric constant are formed on the lower metal. It is formed by being sandwiched between platinum which is the film 30 and platinum which is the upper metal film 60.
  • the “lead electrode” means that the upper metal film 60 and the lower metal film 30 make the piezoelectric film 40 and the low dielectric constant insulating film (the second silicon oxide film 50 in this embodiment) thick. It refers to a place or region sandwiched between directions.
  • the breakdown of the plurality of electrodes 13a to 13d is the two drive electrodes 13a and 13a arranged at an angle of 180 ° from each other in the circumferential direction and the circumferential direction from the drive electrodes 13a and 13a to 90 °.
  • Two monitor electrodes 13c, 13c arranged at an angle apart from each other, and first detection electrodes 13b, 13b and a second detection for detecting a secondary vibration generated when an angular velocity is applied to the ring-shaped vibration gyroscope 100. Electrodes 13d and 13d.
  • the first detection electrodes 13b and 13b are arranged at an angle of 45 ° in the circumferential direction and clockwise from the drive electrodes 13a and 13a.
  • the second detection electrodes 13d and 13d are circumferentially spaced from the first detection electrodes 13b and 13b by 90 °, in other words, from the drive electrodes 13a and 13a in the circumferential direction and counterclockwise. At an angle of 45 °.
  • the lower metal film 30 and the upper metal film 60 have a thickness of 100 nm, and the piezoelectric film 40 has a thickness of 3 ⁇ m.
  • the thickness of the silicon substrate 10 is 100 ⁇ m, and the thickness of the second silicon oxide film 50 is 120 nm.
  • a hatched area indicated by V in FIG. 1 is a space or a gap where there is no structure constituting the ring-shaped vibrating gyroscope 100, and is an area provided for convenience to make the drawing easier to understand.
  • the second region is the leg portions 15,..., 15 connected to a part of the ring-shaped vibrating body 11.
  • the leg portions 15,..., 15 are also formed from the silicon substrate 10. Further, on the leg portions 15,..., 15, the above-described first silicon oxide film 20, lower metal film 30, piezoelectric film 40, and second silicon oxide continuous with those on the ring-shaped vibrating body 11 are provided.
  • a film 50 is formed on the entire upper surface of the leg portions 15. Further, an upper metal film 60 having a width of about 8 ⁇ m is formed on the center line of the upper surface of a part of the piezoelectric film 40 and the second silicon oxide film 50, thereby forming the extraction electrodes 14,. Has been.
  • the third region is a fixed end portion for an electrode pad provided with a support column 19 and electrode pads 18,..., 18 formed from the silicon substrate 10 connected to the leg portions 15,. 17,...
  • the support column 19 is connected to a package portion of the ring-shaped vibrating gyroscope 100 (not shown) and serves as a fixed end.
  • the ring-shaped vibrating gyroscope 100 of the present embodiment includes electrode pad fixed ends 17,..., 17 as fixed ends other than the support column 19.
  • the electrode pad fixed end portions 17,..., 17 are connected only to the support column 19 and the above-described package portion, and therefore do not substantially hinder the movement of the ring-shaped vibrating body 11. Further, as shown in FIG.
  • the leg portions 15,..., 15 are formed on the upper surfaces of the support columns 19 and the electrode pad fixed ends 17,.
  • the first silicon oxide film 20, the lower metal film 30, the piezoelectric film 40, and the second silicon oxide film 50 that are continuous with those above are formed.
  • the lower metal film 30 formed on the first silicon oxide film 20 serves as the fixed potential electrode 16.
  • the upper surface of the second silicon oxide film 50 formed above the support column 19 and the electrode pad fixed ends 17,..., 17 is continuous with that above the leg portions 15,.
  • the lead electrodes 14,..., 14 and the electrode pads 18,..., 18 formed by the upper metal film 60 are formed.
  • the lead electrodes 14,..., 14 on the leg portions 15,... 15 are interposed between the upper metal film 60 and the lower metal film 30 and the piezoelectric film 40.
  • the second silicon oxide film 50 which is a low dielectric constant insulating film, is sandwiched in the thickness direction.
  • the piezoelectric film 40 and the second silicon oxide film 50 also function as a capacitor.
  • the relative dielectric constant of the piezoelectric film 40 is about 1000
  • the relative dielectric constant of the second silicon oxide film 50 is about 4.
  • the synthesized capacitance in the present embodiment is the capacitance when the second silicon oxide film 50 is not formed. To about 9%.
  • the ring-shaped vibrating gyroscope 100 even if the ring-shaped vibrating gyroscope 100 receives an unexpected impact (disturbance) from the outside, only weak polarization (surface charge) is present in the piezoelectric film 40 on the leg portions 15,. It does not occur and the piezoelectric effect is reduced. Therefore, the generation of noise due to such disturbance due to the extraction electrodes 14,.
  • the ring-shaped vibrating gyroscope 100 of the present embodiment has improved impact resistance against external impacts that excite so-called bounce mode and rocking mode vibrations.
  • the intensity of the noise signal not caused by the disturbance is significantly reduced, so that the accuracy of measuring the angular velocity is improved. To do.
  • the second silicon oxide film 50 having a small capacitance is formed, so that the extraction electrodes 14.
  • the voltage is hardly applied to the 14 piezoelectric films 40. That is, as compared with the case where the second silicon oxide film 50 is not provided, the distortion of the piezoelectric film 40 caused by the so-called reverse piezoelectric effect is greatly reduced. As a result, adverse effects on the primary vibration of the ring-shaped vibration gyro 100 can be reduced.
  • the drive electrode 13a and the extraction electrodes 14,..., 14 of the detection electrodes 13b, 13d are only in the approximate center between the outer edge and the inner edge of the upper surface of the leg portions 15,. In other words, it is formed only in the vicinity of the center line). Therefore, as compared with the case where the extraction electrodes 14,..., 14 are formed on substantially the entire surface of the leg portions 15,. The excitation of vibration can be further suppressed.
  • the lead electrodes 14,..., 14 of both the drive electrode 13a and the detection electrodes 13b, 13d are formed only near the center line of the leg portions 15,.
  • the present invention is not limited to this.
  • the lead electrodes 14 and 14 having only the drive electrode 13 a are formed only near the center line of the leg portions 15 and 15, the lead electrodes 14 and 14 are formed on substantially the entire surface of the leg portions 15 and 15. Unnecessary excitation of primary vibration is suppressed compared to time.
  • the extraction electrodes 14,..., 14 of only the detection electrodes 13b, 13d are formed only near the center line of the leg portions 15,. The generation of unnecessary noise can be suppressed as compared with the case where the extraction electrodes 14,..., 14 are formed on substantially the entire upper surface.
  • the above-described second silicon oxide film 50 is not sandwiched between the upper metal film 60 and the lower metal film 30. Therefore, the performance of the piezoelectric film 40 is exhibited as it is.
  • the monitor electrodes 13c and 13c of the present embodiment sandwich the piezoelectric film 40 between the upper metal film 60 and the lower metal film 30 in the thickness direction, like the other electrodes 13a, 13b, and 13d.
  • FIGS. 3A to 3H are cross-sectional views corresponding to a part of the range in FIG.
  • the silicon substrate 10 to be etched is placed on a stage 521 provided on the lower side of the chamber 520.
  • At least one gas selected from an etching gas and an organic deposit forming gas (hereinafter also referred to as a protective film forming gas) is supplied to the chamber 520 from the cylinders 522a and 522b through gas flow rate adjusters 523a and 523b, respectively.
  • the These gases are turned into plasma by a coil 524 to which high frequency power is applied by a first high frequency power source 525. Thereafter, high-frequency power is applied to the stage 521 using the second high-frequency power source 526, so that the generated plasma is drawn into the silicon substrate 10.
  • a vacuum pump 527 is connected to the chamber 520 via an exhaust flow rate regulator 528 to depressurize the chamber 520 and exhaust gas generated after the process.
  • the exhaust flow rate from the chamber 520 is changed by an exhaust flow rate adjuster 528.
  • the gas flow rate adjusters 523a and 523b, the first high frequency power supply 525, the second high frequency power supply 526, and the exhaust flow rate adjuster 528 are controlled by the control unit 529.
  • FIG. 4 has been described as an apparatus configuration for etching the silicon substrate 10, it can also be used as an etching apparatus for the piezoelectric film 40 and the metal film described above.
  • the etching apparatus 500 is used, an object other than silicon, which will be described later, can be etched by appropriately selecting the type of gas introduced into the chamber 520.
  • the first silicon oxide film 20 is a thermal oxide film by a known means.
  • the lower metal film 30 and the piezoelectric film 40 are both formed by a known sputtering method.
  • the second silicon oxide film 50 is formed by a known sputtering method.
  • membranes is not limited to the above-mentioned example, It can form also by another well-known means.
  • the dry etching of the second silicon oxide film 50 is performed by using the above-described etching apparatus 500 and known etching using argon (Ar) or a mixed gas of argon (Ar) and oxygen (O 2 ). Made by condition.
  • a known shadow mask or a lift-off method can be applied to other methods for manufacturing the second silicon oxide film 50.
  • the upper metal film 60 is uniformly laminated on the second silicon oxide film 50 and the piezoelectric film 40.
  • the upper metal film 60 of this embodiment is formed by a known sputtering method.
  • the upper metal film 60 shown in FIG. 3D is formed by performing dry etching based on the pattern formed by the photolithography technique.
  • dry etching of the upper metal film 60 was performed using the above-described etching apparatus 500 under known etching conditions using argon (Ar) or a mixed gas of argon (Ar) and oxygen (O 2 ). .
  • the second silicon oxide film 50 is dry-etched based on a new resist film patterned by the photolithography technique.
  • the dry etching of the second silicon oxide film 50 of the present embodiment is performed by using the above-described etching apparatus 500 and known etching using argon (Ar) or a mixed gas of argon (Ar) and oxygen (O 2 ). Made by condition.
  • a new resist film is formed for the second silicon oxide film 50, but the residual resist film for the upper metal film 60 is used to etch the second silicon oxide film 50. It may be used as an etching mask for.
  • the second silicon oxide film 50 is formed on the piezoelectric film 40.
  • the surface of the lower metal film 30 is not damaged by the patterning of the second silicon oxide film 50 as compared with the case where the second silicon oxide film 50 is formed by patterning on the lower metal film 30. Therefore, there is no influence on the piezoelectric film 40 that is the upper layer. As a result, it is considered that the reliability of the performance of the drive electrode 13a not forming the second silicon oxide film 50 and the detection electrodes 13b and 13d is further increased.
  • the piezoelectric film 40 is dry-etched based on a new resist film patterned by the photolithography technique.
  • the dry etching of the piezoelectric film 40 of the present embodiment by using the etching apparatus 500 described above, and argon (Ar) and C 2 F 6 gas mixed gas, or argon (Ar) and C 2 F 6 gas The etching was performed under known etching conditions using a mixed gas of CHF 3 gas.
  • a new resist film is formed for the piezoelectric film 40, but the residual resist film for the second silicon oxide film 50 is used for etching the piezoelectric film 40. It may be used as an etching mask. This case is also a preferred embodiment because the second silicon oxide film 50 and the piezoelectric film 40 are etched only by forming a new resist film for the second silicon oxide film 50 once.
  • a part of the lower metal film 30 is etched.
  • a part of the lower metal film 30 is formed using the remaining resist film, upper metal film 60, or second silicon oxide film 50 so that the fixed potential electrode 16 using the lower metal film 30 is formed.
  • the fixed potential electrode 16 is used as a ground electrode.
  • the dry etching of the lower layer metal film 30 according to the present embodiment is performed under the known etching conditions using argon (Ar) or a mixed gas of argon (Ar) and oxygen (O 2 ) using the etching apparatus 500 described above. It was conducted.
  • the resist film, the upper metal film 60, the second silicon oxide film 50, or the piezoelectric film 40 formed for etching the piezoelectric film 40 is used as an etching mask, and then the first silicon oxide is formed.
  • the film 20 and the silicon substrate 10 are continuously etched. Therefore, the thickness of this resist film is formed to be about 6 ⁇ m.
  • the etching rate selectivity with respect to the etchant used for the silicon substrate 10 works favorably.
  • the performance of the film 60, the second silicon oxide film 50 immediately below the upper metal film 60, the piezoelectric film 40, and the lower metal film 30 is not substantially affected.
  • the first silicon oxide film 20 and the silicon substrate 10 are used by using the above-described etching apparatus 500 using the resist film formed for etching the piezoelectric film 40 as described above. Dry etching is performed. Dry etching of the first silicon oxide film 20 of the present embodiment was performed under known etching conditions using argon (Ar) or a mixed gas of argon (Ar) and oxygen (O 2 ).
  • through-etching is performed by a dry process of the silicon substrate 10 of the present embodiment.
  • a method of sequentially repeating a protective film forming process in which a protective film forming gas is introduced and an etching process in which an etching gas is introduced is employed.
  • the protective film forming gas is C 4 F 8 and the etching gas is SF 6 .
  • a protective substrate for preventing the stage on which the silicon substrate 10 is placed from being exposed to plasma during penetration is attached to the lower layer of the silicon substrate 10 with grease having excellent heat conductivity. Done. Therefore, for example, in order to prevent the surface in the direction perpendicular to the thickness direction of the silicon substrate 10 after penetration, in other words, the etching side surface from being eroded, the dry etching technique described in JP-A-2002-158214 is employed. This is a preferred embodiment.
  • the central structure of the ring-shaped vibrating gyroscope 100 is formed by etching the silicon substrate 10 and each film laminated on the silicon substrate 10, the process of accommodating the package in a known means, and The ring-shaped vibrating gyroscope 100 is formed through the wiring process.
  • dry etching is employed for all, a vibration gyro with high processing accuracy can be manufactured.
  • each electrode provided in the ring-shaped vibrating gyroscope 100 will be described.
  • the primary vibration of the in-plane cos 2 ⁇ vibration mode is excited. Since the fixed potential electrode 16 is grounded, the lower electrode film 30 formed continuously with the fixed potential electrode 16 is uniformly at 0V.
  • an AC voltage of 1V P-0 is applied to the two drive electrodes 13a and 13a.
  • the piezoelectric film 40 expands and contracts to excite primary vibration.
  • the piezoelectric film 40 since the upper metal film 60 is formed outside the center line on the upper surface of the ring-shaped vibrating body 11, the piezoelectric film 40 is not formed on the side surface of the ring-shaped vibrating body 11. The expansion and contraction motion can be converted into the primary vibration of the ring-shaped vibrating body 11.
  • the monitor electrodes 13c and 13c shown in FIG. 1 detect the amplitude and resonance frequency of the primary vibration described above, and transmit a signal to a known feedback control circuit (not shown).
  • the feedback control circuit of the present embodiment controls the frequency of the alternating voltage applied to the drive electrodes 13a and 13a and the natural frequency of the ring-shaped vibrating body 11 to coincide with each other, and the ring-shaped vibrating body 11 has an amplitude. Control is performed using the signals of the monitor electrodes 13c and 13c so as to obtain a constant value. As a result, the ring-shaped vibrating body 11 maintains constant vibration.
  • the angular velocity around an axis perpendicular to the plane on which the ring-shaped vibrating gyroscope 100 shown in FIG. 1 is arranged (an axis perpendicular to the paper surface, hereinafter simply referred to as “vertical axis”).
  • a secondary vibration having a new vibration axis inclined at 45 ° on both sides with respect to the vibration axis of the primary vibration is generated by the Coriolis force.
  • This secondary vibration is detected by the two first detection electrodes 13b and 13b and the two second detection electrodes 13d and 13d.
  • the first detection electrodes 13b and 13b and the second detection electrodes 13d and 13d are arranged corresponding to the vibration axis of the secondary vibration, respectively. All the first detection electrodes 13 b and 13 b and the second detection electrodes 13 d and 13 d are formed outside the center line on the upper surface of the ring-shaped vibrating body 11. Therefore, the sign of the electrical signals of the first detection electrodes 13b and 13b and the second detection electrodes 13d and 13d generated by the secondary vibration excited by the angular velocity is reversed. As shown in FIG.
  • the arithmetic circuit 70 which is a known difference circuit, the difference between the electrical signals of the first detection electrodes 13b and 13b and the second detection electrodes 13d and 13d is calculated.
  • the detection signal has a detection capability that is approximately twice that of either the first detection signal or the second detection signal.
  • FIG. 5 is a cross-sectional view corresponding to FIG. 2 of another ring-shaped vibrating gyroscope 200 in the present embodiment.
  • the ring-shaped vibrating gyroscope 200 of the present embodiment has the same configuration as the ring-shaped vibrating gyroscope 100 of the first embodiment except for the position of the second silicon oxide film 50 in the first embodiment.
  • the manufacturing method is the same as that of the first embodiment except for a part.
  • the vibration mode of the present embodiment is an in-plane cos 2 ⁇ vibration mode in the same manner as in the first embodiment regarding driving and detection. Therefore, the description which overlaps with 1st Embodiment is abbreviate
  • the second silicon oxide film 50 of the present embodiment is formed between the piezoelectric film 40 and the lower metal film 30.
  • One difference from the manufacturing process of the first embodiment is that before the piezoelectric film 40 is formed on the lower metal film 30, the second silicon oxide film 50 is patterned by a photolithography technique. It is a point.
  • the second silicon oxide film 50, the lower metal film 30, and the first silicon are formed using the resist film as an etching mask.
  • the oxide film 20 and the silicon substrate 10 are dry etched.
  • the etching mask for the piezoelectric film 40 determines the shape of all the underlying films or substrates, so that the manufacturing process is greatly simplified.
  • the selectivity of the etching rate with respect to the etchant used for the silicon substrate 10 is advantageous, so that the upper metal film 60 or The piezoelectric film 40 can function as an etching mask for the lower layer.
  • the second silicon oxide film 50 is not formed in the region where the electrodes such as the drive electrodes 13a and 13a and the first detection electrodes 13b and 13b are formed.
  • the second silicon oxide film 50 and the piezoelectric film 40 are sandwiched between the upper metal film 60 and the lower metal film 30 in the thickness direction. Therefore, the ring-shaped vibrating gyroscope 200 of the present embodiment also has the same effect as that of the first embodiment.
  • FIG. 6 is a cross-sectional view corresponding to FIG. 2 of another ring-shaped vibrating gyroscope 300 according to this embodiment.
  • the ring-shaped vibrating gyroscope 300 of the present embodiment has the same configuration as the ring-shaped vibrating gyroscope 100 of the first embodiment, except for the patterning of the second silicon oxide film 50 in the first embodiment.
  • the manufacturing method is the same as that of the first embodiment except for a part.
  • the vibration mode of the present embodiment is an in-plane cos 2 ⁇ vibration mode in the same manner as in the first embodiment regarding driving and detection. Therefore, the description which overlaps with 1st Embodiment is abbreviate
  • the second silicon oxide film 50 of the present embodiment has substantially the same shape as the upper metal film 60 in plan view.
  • the difference from the manufacturing process of the first embodiment is that the residual portion of the resist film used in etching the upper metal film 60 is used when the second silicon oxide film 50 is etched.
  • the second silicon oxide film 50 is not formed in the region where the electrodes such as the drive electrodes 13a and 13a and the first detection electrodes 13b and 13b are formed.
  • the second silicon oxide film 50 and the piezoelectric film 40 are sandwiched between the upper metal film 60 and the lower metal film 30 in the thickness direction. Therefore, the ring-shaped vibrating gyroscope 300 of this embodiment also has the same effect as that of the first embodiment.
  • the drive electrode and the detection electrode were formed outside the center line, it is not limited to this. Even when the drive electrode and the detection electrode are arranged on the inner side of the center line, the same effect as the effect of the present invention can be obtained.
  • a polygonal vibrating body may be used instead of the annular ring.
  • a regular polygonal vibrator such as a regular hexagon, a regular octagon, a regular dodecagon, and a regular icosahedron
  • a vibrating body such as the octagonal vibrating body 111 of the ring-shaped vibrating gyroscope 400 shown in FIG. 8 may be used.
  • the “annular shape” includes an elliptical shape.
  • the lead electrode 14 employs a configuration in which the piezoelectric film 40 and the second silicon oxide film 50 are sandwiched between the upper metal film 60 and the lower metal film 30. It is not limited. Other low dielectric constant insulating films, such as silicon oxynitride film, silicon nitride film, fluorocarbon film, or polyimide film, can be applied as an alternative to the silicon oxide film. Further, even when a plurality of types of insulating films are applied among the above-described insulating films having a low dielectric constant, the same effects as the effects of the present invention can be obtained.
  • a ring-shaped vibrating gyroscope using silicon as a base material is employed, but the present invention is not limited to this.
  • the base material of the vibration gyro may be silicon germanium.
  • the present invention can be widely applied as a part of various devices as a vibrating gyroscope.

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Abstract

Disclosed is a vibrating gyroscope (100) comprising a piezoelectric film (40). The vibrating gyroscope (100) comprises a circular or polygonal vibrating body (11), a leg part (15) flexibly supporting the vibrating body (11) and having a fixed end, a plurality of electrodes (13b) so formed on the vibrating body (11) as to sandwich the piezoelectric film (40) in the thickness direction with an upper metal film (60) and a lower metal film (30), and a lead electrode (14) so formed on the leg part (15) as to sandwich the piezoelectric film (40) and an insulating film (50) of low dielectric constant in the thickness direction with the upper metalfilm (60) and the lower metal film (30).

Description

[規則91に基づく訂正 07.05.2009]　圧電体膜を用いた振動ジャイロ及びその製造方法[Correction based on Rule 91 07.05.2009] Vibrating gyroscope using piezoelectric film and manufacturing method thereof
　本発明は、圧電体膜を用いた振動ジャイロ及びその製造方法に関するものである。 The present invention relates to a vibration gyro using a piezoelectric film and a method for manufacturing the same.
　近年、圧電材料を用いた振動ジャイロは盛んに開発されている。従来から、特許文献１に記載されているような振動体自体が圧電材料で構成されるジャイロが開発される一方、振動体上に形成される圧電体膜を利用するジャイロも存在する。例えば、特許文献２では、圧電材料であるＰＺＴ膜を用いて、振動体の一次振動を励起し、かつその振動体に角速度が与えられた際に発生するコリオリ力によって生じるジャイロの一部の歪みを検出する技術が開示されている。 In recent years, vibratory gyros using piezoelectric materials have been actively developed. Conventionally, a gyro, in which the vibrator itself is made of a piezoelectric material as described in Patent Document 1, has been developed, and there is also a gyro that uses a piezoelectric film formed on the vibrator. For example, in Patent Document 2, a PZT film, which is a piezoelectric material, is used to excite the primary vibration of a vibrating body, and a part of the gyro distortion caused by Coriolis force generated when an angular velocity is applied to the vibrating body. A technique for detecting the above is disclosed.
　他方、ジャイロが搭載される各種機器のサイズが日進月歩で小型化されている中で、ジャイロ自身の小型化も重要な課題である。ジャイロの小型化を達成するためには、ジャイロを構成する各部材の加工精度を格段に高めることが必要となる。また、小型化と同時に、角速度の検出精度を更に高めたジャイロや、不測の振動（外乱）に対して強いジャイロを提供することが産業界の強い要望といえる。しかしながら、下記の特許文献に示されているジャイロの構造は、ここ数年来の小型化及び高性能化の要求を満足するものではない。 On the other hand, as the size of various devices on which the gyro is mounted is becoming smaller and smaller, the miniaturization of the gyro itself is also an important issue. In order to achieve downsizing of the gyro, it is necessary to remarkably increase the processing accuracy of each member constituting the gyro. Moreover, it can be said that it is a strong demand of the industry to provide a gyro with further improved angular velocity detection accuracy and a gyro that is resistant to unexpected vibration (disturbance). However, the gyro structure shown in the following patent document does not satisfy the demand for miniaturization and high performance over the past several years.
特開平８－２７１２５８号公報JP-A-8-271258 特開２０００－９４７３号公報JP 2000-9473 A
　上述の通り、圧電体膜を用いた振動ジャイロの小型化と高い加工精度を達成しつつ、ジャイロとしての高性能化の要求を同時に満足することは非常に難しい。一般的には、ジャイロが小型化されると、振動体に角速度が与えられた場合に、ジャイロの検出電極によって検出される信号が微弱になるという問題がある。従って、小型化された振動ジャイロは本来検出すべき信号と外部からの不意の衝撃（外乱）によって発生する信号との差が小さくなるため、ジャイロとしての検出精度を高めることが難しくなる。 As described above, it is very difficult to simultaneously satisfy the demand for high performance as a gyro while achieving downsizing and high processing accuracy of a vibration gyro using a piezoelectric film. In general, when the gyro is reduced in size, there is a problem that the signal detected by the detection electrode of the gyro becomes weak when an angular velocity is given to the vibrating body. Therefore, since the size of the vibration gyro reduced in size is small in the difference between the signal that should be detected and the signal that is generated due to an unexpected impact (disturbance) from the outside, it is difficult to improve the detection accuracy of the gyro.
　ところで、外部からの不意の衝撃の中には、様々な種類の衝撃が存在する。例えば、上述の特許文献２に記載されたリング状の振動体では、リングの中心の固定ポストを軸として、リングの存在する面の上下方向にシーソーのような動きを与える衝撃がある。この衝撃により、ロッキングモードと呼ばれる振動が励起される。他方、前述の固定ポストに支持された振動体のリング状部材の全周が同時に、リングの存在する面の上方又は下方に曲げられる衝撃も存在する。この衝撃により、バウンスモードと呼ばれる振動が励起される。これらのような衝撃が振動ジャイロに生じたとしても、正確な角速度を検出する技術を確立することは極めて困難である。 By the way, there are various types of shocks in the external shock. For example, in the ring-shaped vibrating body described in Patent Document 2 described above, there is an impact that causes a seesaw-like movement in the vertical direction of the surface on which the ring exists with the fixed post at the center of the ring as an axis. By this impact, vibration called a rocking mode is excited. On the other hand, there is an impact in which the entire circumference of the ring-shaped member of the vibrating body supported by the fixed post is bent simultaneously above or below the surface where the ring exists. Due to this impact, vibration called a bounce mode is excited. Even if such an impact occurs in the vibrating gyroscope, it is extremely difficult to establish a technique for detecting an accurate angular velocity.
　また、振動ジャイロに対して一次振動を励起する駆動電極や、角速度によって生じる二次振動を検出する検出電極の信号を取り込むために形成される引き出し電極が、製造プロセス上、やむを得ず圧電素子を構成する場合もある。そのような場合に、その引き出し電極自身が生じさせる圧電効果を出来る限り低減することは、振動ジャイロとしての検出精度を高めるために極めて有益である。 In addition, the drive electrode that excites the primary vibration for the vibration gyro and the extraction electrode that is formed to capture the signal of the detection electrode that detects the secondary vibration caused by the angular velocity constitutes a piezoelectric element due to the manufacturing process. In some cases. In such a case, reducing the piezoelectric effect generated by the extraction electrode itself as much as possible is extremely useful for improving the detection accuracy as a vibration gyroscope.
　本発明は、上述の技術課題を解決することにより、圧電体膜を用いた振動ジャイロの小型化及び高性能化に大きく貢献するものである。発明者らは、外乱に対する影響が比較的小さいと考えられる円環状又は多角形状の振動ジャイロを基本構造として採用した。しかしながら、ジャイロの小型化と製造プロセスの簡便化を図る過程で、上述の引き出し電極の形成によって生じるノイズ出力が、比較的小さい出力ではあるが検出精度の更なる向上のためには弊害となることを知見した。そこで、所定の絶縁膜を所定位置にのみ形成することにより、加工精度の高いドライプロセス技術を適用しつつ、その引き出し電極からのノイズ出力を著しく低減することが可能であることを見出した。本発明はこのような視点で創出された。なお、本出願では、「円環状又は多角形状の振動ジャイロ」を、簡略化して「リング状振動ジャイロ」とも呼ぶ。 The present invention greatly contributes to downsizing and high performance of a vibrating gyroscope using a piezoelectric film by solving the above technical problems. The inventors have adopted an annular or polygonal vibration gyro as a basic structure, which is considered to have a relatively small influence on the disturbance. However, in the process of reducing the size of the gyro and simplifying the manufacturing process, the noise output generated by the formation of the extraction electrode described above is a relatively small output, but it is harmful to further improve the detection accuracy. I found out. Thus, it has been found that by forming a predetermined insulating film only at a predetermined position, it is possible to significantly reduce the noise output from the extraction electrode while applying a dry process technique with high processing accuracy. The present invention was created from such a viewpoint. In the present application, the “annular or polygonal vibration gyro” is simply referred to as “ring-shaped vibration gyro”.
　本発明の１つの振動ジャイロは、円環状又は多角形状の振動体と、その振動体を柔軟に支持するとともに固定端を有するレッグ部と、その振動体上に形成されるとともに上層金属膜及び下層金属膜により圧電体膜を厚み方向に挟む複数の電極と、そのレッグ部上に形成されるとともに、前述の上層金属膜及び前述の下層金属膜により圧電体膜及び低誘電率の絶縁膜を厚み方向に挟む引き出し電極とを備えている。尚、本出願において「柔軟な」とは、「振動体が振動可能な程度に」という意味である。 One vibrating gyroscope of the present invention includes an annular or polygonal vibrating body, a leg portion that flexibly supports the vibrating body and has a fixed end, an upper metal film and a lower layer formed on the vibrating body. A plurality of electrodes sandwiching the piezoelectric film in the thickness direction by the metal film and the leg portions, and the piezoelectric film and the low dielectric constant insulating film are formed by the upper metal film and the lower metal film. And a lead electrode sandwiched in the direction. In the present application, “flexible” means “to the extent that the vibrating body can vibrate”.
　この振動ジャイロは、その引き出し電極が、レッグ部上に形成されるとともに、前述の上層金属膜及び前述の下層金属膜によって圧電体膜及び低誘電率の絶縁膜を厚み方向に挟んでいるため、レッグ部上の圧電効果、逆圧電効果、及び静電容量を大幅に低減することができる。すなわち、コンデンサーとしても機能する圧電体膜及び絶縁膜が直列に接続されるため、例えば、その領域に電圧が印加された場合、前述の絶縁体が無い場合と比べて、いわゆる逆圧電効果によって生じる圧電体の歪みは大幅に低減されるため、振動体の一次振動に対する悪影響を減らすことができる。また、レッグ部上のコンデンサーとしての圧電体膜と絶縁膜とが合成された静電容量が、前述の絶縁体が無い場合と比べて大幅に低減される。その結果、上述のような外乱が発生しても、レッグ部上の圧電体膜内には弱い分極（表面電荷）しか発生しなくなって圧電効果が小さくなるため、そのような外乱に対するノイズの発生が抑制される。また、前述のとおり、その領域の合成された静電容量が大幅に低減すると、外乱によらないノイズ信号の強度も顕著に弱まるため、角速度の測定精度が向上する。 In this vibration gyro, the lead electrode is formed on the leg portion, and the piezoelectric film and the low dielectric constant insulating film are sandwiched between the upper metal film and the lower metal film in the thickness direction. The piezoelectric effect, reverse piezoelectric effect, and capacitance on the leg portion can be greatly reduced. That is, since the piezoelectric film and the insulating film that also function as a capacitor are connected in series, for example, when a voltage is applied to the region, it is caused by a so-called reverse piezoelectric effect as compared with the case without the above-described insulator. Since the distortion of the piezoelectric body is greatly reduced, adverse effects on the primary vibration of the vibrating body can be reduced. In addition, the capacitance obtained by synthesizing the piezoelectric film as the capacitor on the leg portion and the insulating film is significantly reduced as compared with the case where there is no insulator. As a result, even if the above disturbance occurs, only weak polarization (surface charge) is generated in the piezoelectric film on the leg portion, and the piezoelectric effect is reduced. Is suppressed. Further, as described above, when the combined capacitance of the region is significantly reduced, the intensity of the noise signal not caused by the disturbance is significantly reduced, so that the measurement accuracy of the angular velocity is improved.
　本発明の１つの振動ジャイロの製造方法は、振動体と、その振動体を柔軟に支持するとともに固定端を有するレッグ部とを備える振動ジャイロの製造方法である。具体的には、上層金属膜と下層金属膜との間に圧電体膜を厚み方向に挟んだ複数の電極を、円環状又は多角形状をした前述の振動体の上方にドライエッチングによって形成する工程と、その上層金属膜とその下層金属膜との間にその圧電体膜と低誘電率の絶縁膜を厚み方向に挟んだ前述の複数の電極の引き出し電極を、そのレッグ部の上方にドライエッチングによって形成する工程とを有している。 One method of manufacturing a vibrating gyroscope according to the present invention is a method of manufacturing a vibrating gyroscope including a vibrating body and a leg portion that flexibly supports the vibrating body and has a fixed end. Specifically, a step of forming, by dry etching, a plurality of electrodes in which a piezoelectric film is sandwiched in the thickness direction between an upper metal film and a lower metal film above the above-described vibrating body having an annular shape or a polygonal shape. And dry etching the lead-out electrodes of the above-mentioned plurality of electrodes with the piezoelectric film and the low dielectric constant insulating film sandwiched between the upper metal film and the lower metal film in the thickness direction above the leg portion. And a process of forming by.
　上述の振動ジャイロの製造方法によれば、ドライプロセス技術による加工が可能となるため、上述の振動体上には駆動や検出を実行する圧電素子を形成するとともに、レッグ部上には、逆圧電効果や圧電効果が抑制される圧電素子を精度良く形成することが可能となる。すなわち、上述の製造方法によって低誘電率の絶縁膜をレッグ部上の所定位置にのみに精度良く形成することにより、レッグ部上の圧電効果、逆圧電効果、及び静電容量を大幅に低減することができる。その結果、不要な振動体の励起を生じさせず、外乱にも強く、さらに、外乱によらないノイズ信号の強度をも顕著に弱めた振動ジャイロを製造することができる。 According to the above-described vibrating gyro manufacturing method, processing by a dry process technique is possible. Therefore, a piezoelectric element that performs driving and detection is formed on the above-described vibrating body, and a reverse piezoelectric element is formed on the leg portion. It is possible to accurately form a piezoelectric element in which the effect and the piezoelectric effect are suppressed. That is, by forming the insulating film having a low dielectric constant accurately only at a predetermined position on the leg portion by the above-described manufacturing method, the piezoelectric effect, reverse piezoelectric effect, and capacitance on the leg portion are greatly reduced. be able to. As a result, it is possible to manufacture a vibrating gyroscope that does not cause unnecessary excitation of a vibrating body, is resistant to disturbances, and further significantly reduces the intensity of noise signals that do not depend on disturbances.
　本発明の１つの振動ジャイロによれば、一次振動の励起状態の信頼性を高めるとともに、角速度が生じた際に高精度に角速度を検出することができる。また、本発明の１つの振動ジャイロの製造方法によれば、ドライプロセス技術による加工により、上述の振動体上には駆動や検出を実行する圧電素子を形成するとともに、レッグ部上には、逆圧電効果や圧電効果が抑制される圧電素子を精度良く形成することが可能となる。その結果、不要な振動体の励起を生じさせず、外乱にも強く、さらに、外乱によらないノイズ信号の強度も顕著に弱めた振動ジャイロを製造することができる。 According to one vibration gyro of the present invention, the reliability of the excited state of the primary vibration can be improved, and the angular velocity can be detected with high accuracy when the angular velocity occurs. Further, according to one method of manufacturing a vibrating gyroscope of the present invention, a piezoelectric element that performs driving and detection is formed on the above-described vibrating body by processing using a dry process technique, and a reverse is provided on the leg portion. It becomes possible to accurately form a piezoelectric element in which the piezoelectric effect and the piezoelectric effect are suppressed. As a result, it is possible to manufacture a vibrating gyroscope that does not cause unnecessary excitation of a vibrating body, is resistant to disturbance, and has a significantly reduced noise signal intensity that does not depend on the disturbance.
本発明の１つの実施形態におけるリング状振動ジャイロの中心的役割を果たす構造体の正面図である。It is a front view of the structure which plays the central role of the ring-shaped vibrating gyroscope in one embodiment of the present invention. 図１のＡ－Ａ断面図である。FIG. 2 is a cross-sectional view taken along the line AA in FIG. 本発明の１つの実施形態におけるリング状振動ジャイロの一部の製造工程の過程を示す断面図である。It is sectional drawing which shows the process of the one part manufacturing process of the ring-shaped vibrating gyroscope in one embodiment of this invention. 本発明の１つの実施形態におけるリング状振動ジャイロの一部の製造工程の過程を示す断面図である。It is sectional drawing which shows the process of the one part manufacturing process of the ring-shaped vibrating gyroscope in one embodiment of this invention. 本発明の１つの実施形態におけるリング状振動ジャイロの一部の製造工程の過程を示す断面図である。It is sectional drawing which shows the process of the one part manufacturing process of the ring-shaped vibrating gyroscope in one embodiment of this invention. 本発明の１つの実施形態におけるリング状振動ジャイロの一部の製造工程の過程を示す断面図である。It is sectional drawing which shows the process of the one part manufacturing process of the ring-shaped vibrating gyroscope in one embodiment of this invention. 本発明の１つの実施形態におけるリング状振動ジャイロの一部の製造工程の過程を示す断面図である。It is sectional drawing which shows the process of the one part manufacturing process of the ring-shaped vibrating gyroscope in one embodiment of this invention. 本発明の１つの実施形態におけるリング状振動ジャイロの一部の製造工程の過程を示す断面図である。It is sectional drawing which shows the process of the one part manufacturing process of the ring-shaped vibrating gyroscope in one embodiment of this invention. 本発明の１つの実施形態におけるリング状振動ジャイロの一部の製造工程の過程を示す断面図である。It is sectional drawing which shows the process of the one part manufacturing process of the ring-shaped vibrating gyroscope in one embodiment of this invention. 本発明の１つの実施形態におけるリング状振動ジャイロの一部の製造工程の過程を示す断面図である。It is sectional drawing which shows the process of the one part manufacturing process of the ring-shaped vibrating gyroscope in one embodiment of this invention. 本発明の１つの実施形態におけるリング状振動ジャイロの製造装置の構成を示す断面図である。It is sectional drawing which shows the structure of the manufacturing apparatus of the ring-shaped vibration gyroscope in one embodiment of this invention. 本発明の他の実施形態における図２に相当する断面図である。It is sectional drawing equivalent to FIG. 2 in other embodiment of this invention. 本発明の他の実施形態における図２に相当する断面図である。It is sectional drawing equivalent to FIG. 2 in other embodiment of this invention. 第１検出電極と第２検出電極の電気的信号の正負を概念的に説明する図である。It is a figure which illustrates notionally positive / negative of the electrical signal of a 1st detection electrode and a 2nd detection electrode. 本発明の他の実施形態における振動体形状を説明する図である。It is a figure explaining the vibrating body shape in other embodiment of this invention.
　本発明の実施形態を、添付する図面に基づいて詳細に述べる。尚、この説明に際し、全図にわたり、特に言及がない限り、共通する部分には共通する参照符号が付されている。また、図中、本実施形態の要素は必ずしもスケール通りに示されていない。また、各図面を見やすくするために、一部の符号が省略され得る。 Embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this description, common parts are denoted by common reference symbols throughout the drawings unless otherwise specified. In the drawings, the elements of the present embodiment are not necessarily shown to scale. Moreover, in order to make each drawing easy to see, some reference numerals may be omitted.
＜第１の実施形態＞
　図１は、本実施形態におけるリング状振動ジャイロ１００の中心的役割を果たす構造体の正面図である。また、図２は、図１のＡ－Ａ断面図である。 <First Embodiment>
FIG. 1 is a front view of a structure that plays a central role in a ring-shaped vibrating gyroscope 100 according to this embodiment. FIG. 2 is a cross-sectional view taken along the line AA in FIG.
　図１及び図２に示すとおり、本実施形態のリング状振動ジャイロ１００は、大きく３つの領域に分類される。第１の領域は、シリコン基板１０から形成されるリング状振動体１１の上部の平面（以下、上面という）上に、複数の膜が積層された領域である。 As shown in FIGS. 1 and 2, the ring-shaped vibrating gyroscope 100 of this embodiment is roughly classified into three regions. The first region is a region in which a plurality of films are stacked on an upper plane (hereinafter referred to as an upper surface) of the ring-shaped vibrating body 11 formed from the silicon substrate 10.
　図１に示す複数の電極１３ａ～１３ｄは、その上面上に、第１シリコン酸化膜２０を備え、その上に、圧電体膜４０であるＰＺＴ膜が、下層金属膜３０である白金（Ｐｔ）と上層金属膜６０である白金（Ｐｔ）との間に挟まれることにより形成される複数の電極１３ａ～１３ｄを備えた領域である。本実施形態では、複数の電極１３ａ～１３ｄを構成する上層金属膜６０は、約４６μｍ幅の上面を有するリング状振動体１１の外周縁から約１μｍ内側に形成され、その幅は約２１μｍである。また、リング状振動体１１の上層金属膜６０は、リング状振動体１１の上面の幅の両端間の中央を結ぶ線（以下、単に中央線という）よりも外側に形成されている。 The plurality of electrodes 13a to 13d shown in FIG. 1 includes a first silicon oxide film 20 on an upper surface thereof, and a PZT film that is a piezoelectric film 40 is formed on platinum (Pt) that is a lower metal film 30. And a plurality of electrodes 13a to 13d formed by being sandwiched between platinum (Pt) as the upper metal film 60. In the present embodiment, the upper metal film 60 constituting the plurality of electrodes 13a to 13d is formed about 1 μm inside from the outer peripheral edge of the ring-shaped vibrating body 11 having an upper surface with a width of about 46 μm, and the width is about 21 μm. . The upper metal film 60 of the ring-shaped vibrating body 11 is formed outside a line connecting the centers between both ends of the width of the upper surface of the ring-shaped vibrating body 11 (hereinafter simply referred to as a center line).
　他方、その複数の電極１３ａ～１３ｄに電圧を印加し、又は電気信号を取得するために引き出し電極１４，・・・，１４が、リング状振動体１１の上面上に形成される。具体的には、リング状振動体１１の上面上に第１シリコン酸化膜２０を備え、その上に、低誘電率の絶縁膜としての第２シリコン酸化膜５０と圧電体膜４０が、下層金属膜３０である白金と上層金属膜６０である白金との間に挟まれることにより形成されている。なお、本出願においては、「引き出し電極」とは、上層金属膜６０と下層金属膜３０により、圧電体膜４０及び低誘電率の絶縁膜（本実施形態では第２シリコン酸化膜５０）が厚み方向に挟まれた場所乃至領域を指す。 On the other hand, extraction electrodes 14,..., 14 are formed on the upper surface of the ring-shaped vibrating body 11 in order to apply a voltage to the plurality of electrodes 13 a to 13 d or acquire an electric signal. Specifically, the first silicon oxide film 20 is provided on the upper surface of the ring-shaped vibrating body 11, and the second silicon oxide film 50 and the piezoelectric film 40 as an insulating film having a low dielectric constant are formed on the lower metal. It is formed by being sandwiched between platinum which is the film 30 and platinum which is the upper metal film 60. In the present application, the “lead electrode” means that the upper metal film 60 and the lower metal film 30 make the piezoelectric film 40 and the low dielectric constant insulating film (the second silicon oxide film 50 in this embodiment) thick. It refers to a place or region sandwiched between directions.
　ところで、本実施形態では、イン・プレーンのｃｏｓ２θの振動モードでリング状振動ジャイロ１００の一次振動が励起される。従って、前述の複数の電極１３ａ～１３ｄの内訳は、互いに円周方向に１８０°離れた角度に配置された２つの駆動電極１３ａ，１３ａと、駆動電極１３ａ，１３ａから円周方向であって９０°離れた角度に配置された２つのモニタ電極１３ｃ，１３ｃと、リング状振動ジャイロ１００に角速度が与えられたときに発生する二次振動を検出する、第１検出電極１３ｂ，１３ｂ及び第２検出電極１３ｄ，１３ｄである。本実施形態では、第１検出電極１３ｂ，１３ｂは、駆動電極１３ａ，１３ａから円周方向であって時計回りに４５°離れた角度に配置される。また、第２検出電極１３ｄ，１３ｄは、第１検出電極１３ｂ，１３ｂから円周方向であって９０°離れた角度、換言すれば、駆動電極１３ａ，１３ａから円周方向であって反時計回りに４５°離れた角度に配置される。 By the way, in this embodiment, the primary vibration of the ring-shaped vibration gyroscope 100 is excited in the in-plane cos 2θ vibration mode. Therefore, the breakdown of the plurality of electrodes 13a to 13d is the two drive electrodes 13a and 13a arranged at an angle of 180 ° from each other in the circumferential direction and the circumferential direction from the drive electrodes 13a and 13a to 90 °. Two monitor electrodes 13c, 13c arranged at an angle apart from each other, and first detection electrodes 13b, 13b and a second detection for detecting a secondary vibration generated when an angular velocity is applied to the ring-shaped vibration gyroscope 100. Electrodes 13d and 13d. In the present embodiment, the first detection electrodes 13b and 13b are arranged at an angle of 45 ° in the circumferential direction and clockwise from the drive electrodes 13a and 13a. Further, the second detection electrodes 13d and 13d are circumferentially spaced from the first detection electrodes 13b and 13b by 90 °, in other words, from the drive electrodes 13a and 13a in the circumferential direction and counterclockwise. At an angle of 45 °.
　また、本実施形態では、下層金属膜３０及び上層金属膜６０の厚みは１００ｎｍであり、圧電体膜４０の厚みは、３μｍである。また、シリコン基板１０の厚みは１００μｍであり、第２シリコン酸化膜５０の厚みは１２０ｎｍである。なお、図１においてＶで示される斜線領域は、リング状振動ジャイロ１００を構成する構造体が何も存在しない空間又は空隙部分であり、図面を分かりやすくするために便宜上設けられた領域である。 In the present embodiment, the lower metal film 30 and the upper metal film 60 have a thickness of 100 nm, and the piezoelectric film 40 has a thickness of 3 μm. The thickness of the silicon substrate 10 is 100 μm, and the thickness of the second silicon oxide film 50 is 120 nm. A hatched area indicated by V in FIG. 1 is a space or a gap where there is no structure constituting the ring-shaped vibrating gyroscope 100, and is an area provided for convenience to make the drawing easier to understand.
　第２の領域は、リング状振動体１１の一部と連結しているレッグ部１５，・・・，１５である。このレッグ部１５，・・・，１５もシリコン基板１０から形成されている。また、レッグ部１５，・・・，１５上には、リング状振動体１１上のそれらと連続する上述の第１シリコン酸化膜２０、下層金属膜３０、圧電体膜４０、及び第２シリコン酸化膜５０がレッグ部１５，・・・，１５の上面全体に形成されている。さらに、一部の圧電体膜４０及び第２シリコン酸化膜５０の上面の中央線上には、幅約８μｍの上層金属膜６０が形成されることにより、引き出し電極１４，・・・，１４が形成されている。 The second region is the leg portions 15,..., 15 connected to a part of the ring-shaped vibrating body 11. The leg portions 15,..., 15 are also formed from the silicon substrate 10. Further, on the leg portions 15,..., 15, the above-described first silicon oxide film 20, lower metal film 30, piezoelectric film 40, and second silicon oxide continuous with those on the ring-shaped vibrating body 11 are provided. A film 50 is formed on the entire upper surface of the leg portions 15. Further, an upper metal film 60 having a width of about 8 μm is formed on the center line of the upper surface of a part of the piezoelectric film 40 and the second silicon oxide film 50, thereby forming the extraction electrodes 14,. Has been.
　第３の領域は、上述のレッグ部１５，・・・，１５に連結しているシリコン基板１０から形成される支柱１９及び電極パッド１８，・・・，１８を備えた電極パッド用固定端部１７，・・・，１７である。本実施形態では、支柱１９が、図示しないリング状振動ジャイロ１００のパッケージ部に連結し、固定端としての役割を果たしている。また、本実施形態のリング状振動ジャイロ１００は、支柱１９以外の固定端として、電極パッド用固定端部１７，・・・，１７を備えている。この電極パッド用固定端部１７，・・・，１７は、支柱１９及び上述のパッケージ部のみに連結しているため、実質的にリング状振動体１１の動きを阻害しない。また、図２に示すように、支柱１９及び電極パッド用固定端部１７，・・・，１７の上面には、グラウンド電極である固定電位電極１６を除き、レッグ部１５，・・・，１５上のそれらと連続する上述の第１シリコン酸化膜２０、下層金属膜３０、圧電体膜４０、及び第２シリコン酸化膜５０が形成されている。ここで、第１シリコン酸化膜２０上に形成された下層金属膜３０が固定電位電極１６の役割を担っている。また、支柱１９及び電極パッド用固定端部１７，・・・，１７の上方に形成されている第２シリコン酸化膜５０の上面には、レッグ部１５，・・・，１５の上方のそれと連続する上層金属膜６０によって形成される引き出し電極１４，・・・，１４及び電極パッド１８，・・・，１８が形成されている。 The third region is a fixed end portion for an electrode pad provided with a support column 19 and electrode pads 18,..., 18 formed from the silicon substrate 10 connected to the leg portions 15,. 17,... In the present embodiment, the support column 19 is connected to a package portion of the ring-shaped vibrating gyroscope 100 (not shown) and serves as a fixed end. Further, the ring-shaped vibrating gyroscope 100 of the present embodiment includes electrode pad fixed ends 17,..., 17 as fixed ends other than the support column 19. The electrode pad fixed end portions 17,..., 17 are connected only to the support column 19 and the above-described package portion, and therefore do not substantially hinder the movement of the ring-shaped vibrating body 11. Further, as shown in FIG. 2, the leg portions 15,..., 15 are formed on the upper surfaces of the support columns 19 and the electrode pad fixed ends 17,. The first silicon oxide film 20, the lower metal film 30, the piezoelectric film 40, and the second silicon oxide film 50 that are continuous with those above are formed. Here, the lower metal film 30 formed on the first silicon oxide film 20 serves as the fixed potential electrode 16. Further, the upper surface of the second silicon oxide film 50 formed above the support column 19 and the electrode pad fixed ends 17,..., 17 is continuous with that above the leg portions 15,. The lead electrodes 14,..., 14 and the electrode pads 18,..., 18 formed by the upper metal film 60 are formed.
　上述の構造が採用されることにより、レッグ部１５，・・・，１５上の引き出し電極１４，・・・，１４が、上層金属膜６０と下層金属膜３０との間に圧電体膜４０及び低誘電率の絶縁膜である第２シリコン酸化膜５０を厚み方向に挟むことになる。ここで、圧電体膜４０と第２シリコン酸化膜５０は、コンデンサーとしても機能する。本実施形態では、圧電体膜４０の比誘電率が約１０００であるのに対し、第２シリコン酸化膜５０の比誘電率は約４である。そうすると、圧電体膜４０と第２シリコン酸化膜５０が直列に接続されることにより、本実施形態における合成された静電容量は、第２シリコン酸化膜５０が形成されていない場合の静電容量の約９％にまで低減する。 By adopting the above-described structure, the lead electrodes 14,..., 14 on the leg portions 15,... 15 are interposed between the upper metal film 60 and the lower metal film 30 and the piezoelectric film 40. The second silicon oxide film 50, which is a low dielectric constant insulating film, is sandwiched in the thickness direction. Here, the piezoelectric film 40 and the second silicon oxide film 50 also function as a capacitor. In the present embodiment, the relative dielectric constant of the piezoelectric film 40 is about 1000, whereas the relative dielectric constant of the second silicon oxide film 50 is about 4. Then, since the piezoelectric film 40 and the second silicon oxide film 50 are connected in series, the synthesized capacitance in the present embodiment is the capacitance when the second silicon oxide film 50 is not formed. To about 9%.
　その結果、例えば、リング状振動ジャイロ１００が外部からの不意の衝撃（外乱）を受けても、レッグ部１５，・・・，１５上の圧電体膜４０内には弱い分極（表面電荷）しか発生しなくなって圧電効果が小さくなる。従って、引き出し電極１４，・・・，１４に起因するそのような外乱に対するノイズの発生が大幅に抑制される。換言すれば、本実施形態のリング状振動ジャイロ１００は、いわゆるバウンスモードやロッキングモードの振動を励起する外部衝撃に対する耐衝撃性が高められている。また、前述のとおり、引き出し電極１４，・・・，１４の領域の合成された静電容量が大幅に低減すると、外乱によらないノイズ信号の強度も顕著に弱まるため、角速度の測定精度が向上する。 As a result, for example, even if the ring-shaped vibrating gyroscope 100 receives an unexpected impact (disturbance) from the outside, only weak polarization (surface charge) is present in the piezoelectric film 40 on the leg portions 15,. It does not occur and the piezoelectric effect is reduced. Therefore, the generation of noise due to such disturbance due to the extraction electrodes 14,. In other words, the ring-shaped vibrating gyroscope 100 of the present embodiment has improved impact resistance against external impacts that excite so-called bounce mode and rocking mode vibrations. Further, as described above, when the combined capacitance in the region of the extraction electrodes 14,..., 14 is significantly reduced, the intensity of the noise signal not caused by the disturbance is significantly reduced, so that the accuracy of measuring the angular velocity is improved. To do.
　さらに、例えば、その領域に駆動電極１３ａ，１３ａに与えられる電圧が印加された場合であっても、静電容量の小さい第２シリコン酸化膜５０が形成されているため、引き出し電極１４，・・・，１４の圧電体膜４０に対しては殆ど電圧が印加されなくなる。すなわち、第２シリコン酸化膜５０が無い場合と比べて、いわゆる逆圧電効果によって生じる圧電体膜４０の歪みは大幅に低減される。その結果、リング状振動ジャイロ１００の一次振動に対する悪影響を減らすことができる。 Furthermore, for example, even when a voltage applied to the drive electrodes 13a and 13a is applied to the region, the second silicon oxide film 50 having a small capacitance is formed, so that the extraction electrodes 14. The voltage is hardly applied to the 14 piezoelectric films 40. That is, as compared with the case where the second silicon oxide film 50 is not provided, the distortion of the piezoelectric film 40 caused by the so-called reverse piezoelectric effect is greatly reduced. As a result, adverse effects on the primary vibration of the ring-shaped vibration gyro 100 can be reduced.
　特に、本実施形態では、駆動電極１３ａと各検出電極１３ｂ，１３ｄの引き出し電極１４，・・・，１４が、レッグ部１５，・・・，１５の上面の外縁と内縁との略中央のみ（換言すれば、中央線付近のみ）に形成されている。従って、レッグ部１５，・・・，１５上の略全面上に引き出し電極１４，・・・，１４が形成されている場合と比較して、検出の際の不要なノイズの発生及び不要な一次振動の励起をさらに抑えることができる。 In particular, in the present embodiment, the drive electrode 13a and the extraction electrodes 14,..., 14 of the detection electrodes 13b, 13d are only in the approximate center between the outer edge and the inner edge of the upper surface of the leg portions 15,. In other words, it is formed only in the vicinity of the center line). Therefore, as compared with the case where the extraction electrodes 14,..., 14 are formed on substantially the entire surface of the leg portions 15,. The excitation of vibration can be further suppressed.
　ところで、本実施形態では、駆動電極１３ａと各検出電極１３ｂ，１３ｄの双方の引き出し電極１４，・・・，１４がレッグ部１５，・・・，１５の中央線付近のみに形成されているが、これに限定されない。例えば、駆動電極１３ａのみの引き出し電極１４，１４がレッグ部１５，１５の中央線付近のみに形成された場合、レッグ部１５，１５上の略全面上に引き出し電極１４，１４が形成されている時と比較して不要な一次振動の励起が抑制される。他方、各検出電極１３ｂ，１３ｄのみの引き出し電極１４，・・・，１４がレッグ部１５，・・・，１５の中央線付近のみに形成された場合は、レッグ部１５，・・・，１５上の略全面上に引き出し電極１４，・・・，１４が形成されている時と比較して不要なノイズの発生が抑えられる。 By the way, in the present embodiment, the lead electrodes 14,..., 14 of both the drive electrode 13a and the detection electrodes 13b, 13d are formed only near the center line of the leg portions 15,. However, the present invention is not limited to this. For example, when the lead electrodes 14 and 14 having only the drive electrode 13 a are formed only near the center line of the leg portions 15 and 15, the lead electrodes 14 and 14 are formed on substantially the entire surface of the leg portions 15 and 15. Unnecessary excitation of primary vibration is suppressed compared to time. On the other hand, when the extraction electrodes 14,..., 14 of only the detection electrodes 13b, 13d are formed only near the center line of the leg portions 15,. The generation of unnecessary noise can be suppressed as compared with the case where the extraction electrodes 14,..., 14 are formed on substantially the entire upper surface.
　他方、駆動電極１３ａ及び各検出電極１３ｂ，１３ｄは、上層金属膜６０と下層金属膜３０との間に上述の第２シリコン酸化膜５０が挟まれていない。従って、圧電体膜４０の性能がそのまま発揮されることになる。 On the other hand, in the drive electrode 13a and each of the detection electrodes 13b and 13d, the above-described second silicon oxide film 50 is not sandwiched between the upper metal film 60 and the lower metal film 30. Therefore, the performance of the piezoelectric film 40 is exhibited as it is.
　従って、本実施形態のリング状振動ジャイロ１００を用いることにより、振動体の駆動や角速度の検出の性能を維持しつつ、不要なノイズの発生や不要な一次振動の励起を顕著に抑えることができる。なお、本実施形態のモニタ電極１３ｃ，１３ｃは、その他の各電極１３ａ，１３ｂ，１３ｄと同様、上層金属膜６０と下層金属膜３０との間に圧電体膜４０を厚み方向に挟んでいる。 Therefore, by using the ring-shaped vibrating gyroscope 100 of the present embodiment, it is possible to significantly suppress the generation of unnecessary noise and unnecessary excitation of primary vibration while maintaining the performance of driving the vibrating body and detecting the angular velocity. . The monitor electrodes 13c and 13c of the present embodiment sandwich the piezoelectric film 40 between the upper metal film 60 and the lower metal film 30 in the thickness direction, like the other electrodes 13a, 13b, and 13d.
　次に、本実施形態のリング状振動ジャイロ１００の製造方法について、図３Ａ乃至図３Ｈに基づいて説明する。なお、図３Ａ乃至図３Ｈは、図２における一部の範囲に対応する断面図である。 Next, a method for manufacturing the ring-shaped vibrating gyroscope 100 according to this embodiment will be described with reference to FIGS. 3A to 3H. 3A to 3H are cross-sectional views corresponding to a part of the range in FIG.
　まず、図４に示すシリコン基板１０のエッチング装置５００の構成について説明する。エッチング対象となるシリコン基板１０は、チャンバー５２０の下部側に設けられたステージ５２１に載置される。チャンバー５２０には、エッチングガス、有機堆積物形成ガス（以下、保護膜形成ガスともいう）から選ばれる少なくとも一種類のガスが、各ボンベ５２２ａ，５２２ｂからそれぞれガス流量調整器５２３ａ，５２３ｂを通して供給される。これらのガスは、第１高周波電源５２５により高周波電力を印加されたコイル５２４によりプラズマ化される。その後、第２高周波電源５２６を用いてステージ５２１に高周波電力が印加されることにより、これらの生成されたプラズマはシリコン基板１０に引き込まれる。このチャンバー５２０内を減圧し、かつプロセス後に生成されるガスを排気するため、チャンバー５２０には真空ポンプ５２７が排気流量調整器５２８を介して接続されている。尚、このチャンバー５２０からの排気流量は排気流量調整器５２８により変更される。上述のガス流量調整器５２３ａ，５２３ｂ、第１高周波電源５２５、第２高周波電源５２６及び排気流量調整器５２８は、制御部５２９により制御される。なお、図４は、シリコン基板１０をエッチングするための装置構成として説明されたが、上述の圧電体膜４０や金属膜のためのエッチング装置としても利用され得る。例えば、エッチング装置５００を用いれば、チャンバー５２０内に導入するガスの種類を適宜選定することによって、後述のシリコン以外の対象をエッチングすることもできる。 First, the configuration of the etching apparatus 500 for the silicon substrate 10 shown in FIG. 4 will be described. The silicon substrate 10 to be etched is placed on a stage 521 provided on the lower side of the chamber 520. At least one gas selected from an etching gas and an organic deposit forming gas (hereinafter also referred to as a protective film forming gas) is supplied to the chamber 520 from the cylinders 522a and 522b through gas flow rate adjusters 523a and 523b, respectively. The These gases are turned into plasma by a coil 524 to which high frequency power is applied by a first high frequency power source 525. Thereafter, high-frequency power is applied to the stage 521 using the second high-frequency power source 526, so that the generated plasma is drawn into the silicon substrate 10. A vacuum pump 527 is connected to the chamber 520 via an exhaust flow rate regulator 528 to depressurize the chamber 520 and exhaust gas generated after the process. The exhaust flow rate from the chamber 520 is changed by an exhaust flow rate adjuster 528. The gas flow rate adjusters 523a and 523b, the first high frequency power supply 525, the second high frequency power supply 526, and the exhaust flow rate adjuster 528 are controlled by the control unit 529. Although FIG. 4 has been described as an apparatus configuration for etching the silicon substrate 10, it can also be used as an etching apparatus for the piezoelectric film 40 and the metal film described above. For example, if the etching apparatus 500 is used, an object other than silicon, which will be described later, can be etched by appropriately selecting the type of gas introduced into the chamber 520.
　本実施形態のリング状振動ジャイロ１００の製造方法では、最初に、図３Ａに示すように、シリコン基板１０上に、第１シリコン酸化膜２０、下層金属膜３０、圧電体膜４０、第２シリコン酸化膜５０が積層される。前述の各膜は公知の成膜手段によって形成されている。本実施形態では、第１シリコン酸化膜２０は公知の手段による熱酸化膜である。また、下層金属膜３０、及び圧電体膜４０は、いずれも公知のスパッタリング法により形成されている。また、第２シリコン酸化膜５０は、公知のスパッタリング法によって形成されている。なお、これらの膜の形成は、前述の例に限定されず、他の公知の手段によっても形成され得る。 In the manufacturing method of the ring-shaped vibrating gyroscope 100 of the present embodiment, first, as shown in FIG. 3A, on the silicon substrate 10, the first silicon oxide film 20, the lower metal film 30, the piezoelectric film 40, and the second silicon An oxide film 50 is stacked. Each of the aforementioned films is formed by a known film forming means. In the present embodiment, the first silicon oxide film 20 is a thermal oxide film by a known means. The lower metal film 30 and the piezoelectric film 40 are both formed by a known sputtering method. The second silicon oxide film 50 is formed by a known sputtering method. In addition, formation of these films | membranes is not limited to the above-mentioned example, It can form also by another well-known means.
　次に、第２シリコン酸化膜５０の一部がエッチングされる。本実施形態では、第２シリコン酸化膜５０上に公知のレジスト膜を形成した後、フォトリソグラフィ技術により形成されたパターンに基づいてドライエッチングを行うことにより、図３Ｂに示される第２シリコン酸化膜５０が形成される。ここで、第２シリコン酸化膜５０のドライエッチングは、上述のエッチング装置５００を用いて、アルゴン（Ａｒ）、又は、アルゴン（Ａｒ）と酸素（Ｏ２）との混合ガスを用いた公知のエッチング条件によって行われた。なお、第２シリコン酸化膜５０のその他の製造方法には、公知のシャドーマスクやリフトオフ法も適用され得る。 Next, a part of the second silicon oxide film 50 is etched. In the present embodiment, after a known resist film is formed on the second silicon oxide film 50, dry etching is performed based on a pattern formed by a photolithography technique, whereby the second silicon oxide film shown in FIG. 3B is obtained. 50 is formed. Here, the dry etching of the second silicon oxide film 50 is performed by using the above-described etching apparatus 500 and known etching using argon (Ar) or a mixed gas of argon (Ar) and oxygen (O 2 ). Made by condition. A known shadow mask or a lift-off method can be applied to other methods for manufacturing the second silicon oxide film 50.
　その後、図３Ｃに示すように、第２シリコン酸化膜５０及び圧電体膜４０上に、上層金属膜６０が一様に積層される。尚、本実施形態の上層金属膜６０は、公知のスパッタリング法により形成されている。 Thereafter, as shown in FIG. 3C, the upper metal film 60 is uniformly laminated on the second silicon oxide film 50 and the piezoelectric film 40. Note that the upper metal film 60 of this embodiment is formed by a known sputtering method.
　次に、上層金属膜６０の一部がエッチングされる。本実施形態では、上層金属膜６０上に公知のレジスト膜を形成した後、フォトリソグラフィ技術により形成されたパターンに基づいてドライエッチングを行うことにより、図３Ｄに示される上層金属膜６０が形成される。ここで、上層金属膜６０のドライエッチングは、上述のエッチング装置５００を用いて、アルゴン（Ａｒ）又はアルゴン（Ａｒ）と酸素（Ｏ２）の混合ガスを用いた公知のエッチング条件によって行われた。 Next, a part of the upper metal film 60 is etched. In the present embodiment, after forming a known resist film on the upper metal film 60, the upper metal film 60 shown in FIG. 3D is formed by performing dry etching based on the pattern formed by the photolithography technique. The Here, dry etching of the upper metal film 60 was performed using the above-described etching apparatus 500 under known etching conditions using argon (Ar) or a mixed gas of argon (Ar) and oxygen (O 2 ). .
　その後、図３Ｅに示すように、第２シリコン酸化膜５０の一部がエッチングされる。まず、上述と同様、フォトリソグラフィ技術によりパターニングがされた新たなレジスト膜に基づいて、第２シリコン酸化膜５０がドライエッチングされる。なお、本実施形態の第２シリコン酸化膜５０のドライエッチングは、上述のエッチング装置５００を用いて、アルゴン（Ａｒ）又はアルゴン（Ａｒ）と酸素（Ｏ２）の混合ガスを用いた公知のエッチング条件によって行われた。なお、本実施形態では、第２シリコン酸化膜５０のために新たなレジスト膜が形成されたが、上述の上層金属膜６０のためのレジスト膜の残留分が、第２シリコン酸化膜５０のエッチングのためのエッチングマスクとして利用されてもよい。その場合は、後述する図６に示す断面構造が形成される。すなわち、上述の上層金属膜６０のためのレジスト膜の残留分を利用すれば、パターニングされたレジスト膜の形成工程が１回削減できる。なお、本実施形態では、第２シリコン酸化膜５０が圧電体膜４０上に形成されている。この場合、下層金属膜３０上に第２シリコン酸化膜５０がパターニングされて形成される場合と比較して、下層金属膜３０の表面が第２シリコン酸化膜５０のパターニングによってダメージを受けることが無いため、その上層である圧電体膜４０への影響は生じない。その結果、第２シリコン酸化膜５０を形成しない駆動電極１３ａと各検出電極１３ｂ，１３ｄの性能の信頼性がより高まると考えられる。 Thereafter, as shown in FIG. 3E, a part of the second silicon oxide film 50 is etched. First, as described above, the second silicon oxide film 50 is dry-etched based on a new resist film patterned by the photolithography technique. In addition, the dry etching of the second silicon oxide film 50 of the present embodiment is performed by using the above-described etching apparatus 500 and known etching using argon (Ar) or a mixed gas of argon (Ar) and oxygen (O 2 ). Made by condition. In the present embodiment, a new resist film is formed for the second silicon oxide film 50, but the residual resist film for the upper metal film 60 is used to etch the second silicon oxide film 50. It may be used as an etching mask for. In that case, a cross-sectional structure shown in FIG. 6 described later is formed. That is, if the resist film residue for the upper metal film 60 is used, the process for forming the patterned resist film can be reduced once. In the present embodiment, the second silicon oxide film 50 is formed on the piezoelectric film 40. In this case, the surface of the lower metal film 30 is not damaged by the patterning of the second silicon oxide film 50 as compared with the case where the second silicon oxide film 50 is formed by patterning on the lower metal film 30. Therefore, there is no influence on the piezoelectric film 40 that is the upper layer. As a result, it is considered that the reliability of the performance of the drive electrode 13a not forming the second silicon oxide film 50 and the detection electrodes 13b and 13d is further increased.
　その後、図３Ｆに示すように、圧電体膜４０の一部がエッチングされる。まず、上述と同様、フォトリソグラフィ技術によりパターニングされた新たなレジスト膜に基づいて、圧電体膜４０がドライエッチングされる。なお、本実施形態の圧電体膜４０のドライエッチングは、上述のエッチング装置５００を用いて、アルゴン（Ａｒ）とＣ２Ｆ６ガスの混合ガス、又はアルゴン（Ａｒ）とＣ２Ｆ６ガスとＣＨＦ３ガスの混合ガスを用いた公知のエッチング条件によって行われた。なお、本実施形態では、圧電体膜４０のために新たなレジスト膜が形成されたが、上述の第２シリコン酸化膜５０のためのレジスト膜の残留分が、圧電体膜４０のエッチングのためのエッチングマスクとして利用されてもよい。この場合も、第２シリコン酸化膜５０のための新たなレジスト膜が１回形成されるだけで、第２シリコン酸化膜５０及び圧電体膜４０がエッチングされるため、好ましい一態様である。 Thereafter, as shown in FIG. 3F, a part of the piezoelectric film 40 is etched. First, as described above, the piezoelectric film 40 is dry-etched based on a new resist film patterned by the photolithography technique. Incidentally, the dry etching of the piezoelectric film 40 of the present embodiment, by using the etching apparatus 500 described above, and argon (Ar) and C 2 F 6 gas mixed gas, or argon (Ar) and C 2 F 6 gas The etching was performed under known etching conditions using a mixed gas of CHF 3 gas. In the present embodiment, a new resist film is formed for the piezoelectric film 40, but the residual resist film for the second silicon oxide film 50 is used for etching the piezoelectric film 40. It may be used as an etching mask. This case is also a preferred embodiment because the second silicon oxide film 50 and the piezoelectric film 40 are etched only by forming a new resist film for the second silicon oxide film 50 once.
　続いて、図３Ｇに示すように、下層金属膜３０の一部がエッチングされる。本実施形態では、下層金属膜３０を利用した固定電位電極１６が形成されるように、残留するレジスト膜、上層金属膜６０、又は第２シリコン酸化膜５０を用いて下層金属膜３０の一部がドライエッチングされる。本実施形態では、固定電位電極１６は、グラウンド電極として利用される。なお、本実施形態の下層金属膜３０のドライエッチングは、上述のエッチング装置５００を用いて、アルゴン（Ａｒ）又はアルゴン（Ａｒ）と酸素（Ｏ２）の混合ガスを用いた公知のエッチング条件によって行われた。 Subsequently, as shown in FIG. 3G, a part of the lower metal film 30 is etched. In the present embodiment, a part of the lower metal film 30 is formed using the remaining resist film, upper metal film 60, or second silicon oxide film 50 so that the fixed potential electrode 16 using the lower metal film 30 is formed. Is dry etched. In the present embodiment, the fixed potential electrode 16 is used as a ground electrode. The dry etching of the lower layer metal film 30 according to the present embodiment is performed under the known etching conditions using argon (Ar) or a mixed gas of argon (Ar) and oxygen (O 2 ) using the etching apparatus 500 described above. It was conducted.
　ところで、本実施形態では、圧電体膜４０をエッチングするために形成されたレジスト膜、上層金属膜６０、第２シリコン酸化膜５０、又は圧電体膜４０をエッチングマスクとして、その後の第１シリコン酸化膜２０及びシリコン基板１０を連続的にエッチングする。そのため、このレジスト膜の厚みは、約６μｍになるように形成されている。但し、万一、このレジスト膜が、シリコン基板１０のエッチング中に消失した場合であっても、シリコン基板１０に用いられるエッチャントに対するエッチングレートの選択比が有利に働くため、前述のエッチングによって上層金属膜６０、上層金属膜６０直下の第２シリコン酸化膜５０、圧電体膜４０、及び下層金属膜３０の性能は実質的に影響を受けない。 By the way, in the present embodiment, the resist film, the upper metal film 60, the second silicon oxide film 50, or the piezoelectric film 40 formed for etching the piezoelectric film 40 is used as an etching mask, and then the first silicon oxide is formed. The film 20 and the silicon substrate 10 are continuously etched. Therefore, the thickness of this resist film is formed to be about 6 μm. However, even if this resist film disappears during the etching of the silicon substrate 10, the etching rate selectivity with respect to the etchant used for the silicon substrate 10 works favorably. The performance of the film 60, the second silicon oxide film 50 immediately below the upper metal film 60, the piezoelectric film 40, and the lower metal film 30 is not substantially affected.
　次に、図３Ｈに示すように、上述の通り圧電体膜４０をエッチングするために形成されたレジスト膜を利用して、上述のエッチング装置５００を用いて第１シリコン酸化膜２０及びシリコン基板１０のドライエッチングが行われる。本実施形態の第１シリコン酸化膜２０のドライエッチングは、アルゴン（Ａｒ）又はアルゴン（Ａｒ）と酸素（Ｏ２）の混合ガスを用いた公知のエッチング条件によって行われた。 Next, as shown in FIG. 3H, the first silicon oxide film 20 and the silicon substrate 10 are used by using the above-described etching apparatus 500 using the resist film formed for etching the piezoelectric film 40 as described above. Dry etching is performed. Dry etching of the first silicon oxide film 20 of the present embodiment was performed under known etching conditions using argon (Ar) or a mixed gas of argon (Ar) and oxygen (O 2 ).
　その後、本実施形態のシリコン基板１０のドライプロセスによる貫通エッチングが行われる。本実施形態では、保護膜形成ガスが導入される保護膜形成工程とエッチングガスが導入されるエッチング工程とを順次繰り返す方法が採用される。尚、本実施形態の保護膜形成ガスはＣ４Ｆ８であり、エッチングガスはＳＦ６である。 Thereafter, through-etching is performed by a dry process of the silicon substrate 10 of the present embodiment. In the present embodiment, a method of sequentially repeating a protective film forming process in which a protective film forming gas is introduced and an etching process in which an etching gas is introduced is employed. In this embodiment, the protective film forming gas is C 4 F 8 and the etching gas is SF 6 .
　また、前述のドライエッチングは、貫通時にシリコン基板１０を載置するステージをプラズマに曝さないようにするための保護基板をシリコン基板１０の下層に伝熱性の優れたグリース等により貼り付けた状態で行われる。そのため、例えば、貫通後にシリコン基板１０の厚さ方向に垂直な方向の面、換言すればエッチング側面が侵食されることを防ぐために、特開２００２－１５８２１４に記載されているドライエッチング技術が採用されることは好ましい一態様である。 In the dry etching described above, a protective substrate for preventing the stage on which the silicon substrate 10 is placed from being exposed to plasma during penetration is attached to the lower layer of the silicon substrate 10 with grease having excellent heat conductivity. Done. Therefore, for example, in order to prevent the surface in the direction perpendicular to the thickness direction of the silicon substrate 10 after penetration, in other words, the etching side surface from being eroded, the dry etching technique described in JP-A-2002-158214 is employed. This is a preferred embodiment.
　上述の通り、シリコン基板１０及びシリコン基板１０上に積層された各膜のエッチングによって、リング状振動ジャイロ１００の中心的な構造部が形成されたのち、公知の手段によるパッケージへの収容工程、及び配線工程を経ることにより、リング状振動ジャイロ１００が形成される。本実施形態では、全てドライエッチングが採用されているため、加工精度の高い振動ジャイロが製造できる。 As described above, after the central structure of the ring-shaped vibrating gyroscope 100 is formed by etching the silicon substrate 10 and each film laminated on the silicon substrate 10, the process of accommodating the package in a known means, and The ring-shaped vibrating gyroscope 100 is formed through the wiring process. In this embodiment, since dry etching is employed for all, a vibration gyro with high processing accuracy can be manufactured.
　次に、リング状振動ジャイロ１００が備える各電極の作用について説明する。上述の通り、本実施形態はイン・プレーンのｃｏｓ２θの振動モードの一次振動が励起される。なお、固定電位電極１６が接地されるため、固定電位電極１６と連続して形成されている下層電極膜３０は一律に０Ｖになっている。 Next, the operation of each electrode provided in the ring-shaped vibrating gyroscope 100 will be described. As described above, in the present embodiment, the primary vibration of the in-plane cos 2θ vibration mode is excited. Since the fixed potential electrode 16 is grounded, the lower electrode film 30 formed continuously with the fixed potential electrode 16 is uniformly at 0V.
　最初に、図１に示すように、２つの駆動電極１３ａ，１３ａに１ＶＰ－０の交流電圧が印加される。その結果、圧電体膜４０が伸縮して一次振動が励起される。ここで、本実施形態では上層金属膜６０がリング状振動体１１の上面における中央線よりも外側に形成されているため、リング状振動体１１の側面に形成されることなく圧電体膜４０の伸縮運動をリング状振動体１１の一次振動に変換することが可能となる。 First, as shown in FIG. 1, an AC voltage of 1V P-0 is applied to the two drive electrodes 13a and 13a. As a result, the piezoelectric film 40 expands and contracts to excite primary vibration. Here, in this embodiment, since the upper metal film 60 is formed outside the center line on the upper surface of the ring-shaped vibrating body 11, the piezoelectric film 40 is not formed on the side surface of the ring-shaped vibrating body 11. The expansion and contraction motion can be converted into the primary vibration of the ring-shaped vibrating body 11.
　次に、図１に示すモニタ電極１３ｃ，１３ｃが、上述の一次振動の振幅及び共振周波数を検出して、図示しない公知のフィードバック制御回路に信号を送信する。本実施形態のフィードバック制御回路は、駆動電極１３ａ，１３ａに印加される交流電圧の周波数とリング状振動体１１が持つ固有周波数が一致するように制御するとともに、リング状振動体１１の振幅がある一定の値となるようにモニタ電極１３ｃ，１３ｃの信号を用いて制御している。その結果、リング状振動体１１は、一定の振動が持続される。 Next, the monitor electrodes 13c and 13c shown in FIG. 1 detect the amplitude and resonance frequency of the primary vibration described above, and transmit a signal to a known feedback control circuit (not shown). The feedback control circuit of the present embodiment controls the frequency of the alternating voltage applied to the drive electrodes 13a and 13a and the natural frequency of the ring-shaped vibrating body 11 to coincide with each other, and the ring-shaped vibrating body 11 has an amplitude. Control is performed using the signals of the monitor electrodes 13c and 13c so as to obtain a constant value. As a result, the ring-shaped vibrating body 11 maintains constant vibration.
　上述の一次振動が励起された後、図１に示すリング状振動ジャイロ１００の配置された平面に垂直な軸（紙面に垂直な方向の軸、以下、単に「垂直軸」という）の回りで角速度が加わると、ｃｏｓ２θの振動モードである本実施形態では、コリオリ力により一次振動の振動軸に対して両側に４５°傾いた新たな振動軸を有する二次振動が生じる。 After the above-described primary vibration is excited, the angular velocity around an axis perpendicular to the plane on which the ring-shaped vibrating gyroscope 100 shown in FIG. 1 is arranged (an axis perpendicular to the paper surface, hereinafter simply referred to as “vertical axis”). In this embodiment, which is a cos 2θ vibration mode, a secondary vibration having a new vibration axis inclined at 45 ° on both sides with respect to the vibration axis of the primary vibration is generated by the Coriolis force.
　この二次振動が２つの第１検出電極１３ｂ，１３ｂと、２つの第２検出電極１３ｄ，１３ｄによって検出される。本実施形態では、図１に示すように、第１検出電極１３ｂ，１３ｂ及び第２検出電極１３ｄ，１３ｄは、それぞれ二次振動の振動軸に対応して配置されている。また、全ての第１検出電極１３ｂ，１３ｂ及び第２検出電極１３ｄ，１３ｄは、リング状振動体１１の上面における中央線よりも外側に形成されている。従って、角速度を受けて励起される二次振動によって生じる第１検出電極１３ｂ，１３ｂと第２検出電極１３ｄ，１３ｄの電気的信号の正負が逆になる。これは、図７に示すように、例えば、リング状振動体１１が縦に楕円となる振動体１１ａの振動状態に変化した場合、中央線より外側に配置されている第１検出電極１３ｂの位置の圧電体膜４０は、Ａ１に示す矢印の方向に伸びる一方、中央線より外側に配置されている第２検出電極１３ｄの位置の圧電体膜４０は、Ａ２に示す矢印の方向に縮むため、それらの電気的信号は逆になる。同様に、リング状振動体１１が横に楕円となる振動体１１ｂの振動状態に変化した場合、第１検出電極１３ｂの位置の圧電体膜４０は、Ｂ１に示す矢印の方向に縮む一方、第２検出電極１３ｄの位置の圧電体膜４０は、Ｂ２に示す矢印の方向に伸びるため、この場合も、それらの電気的信号が逆になる。 This secondary vibration is detected by the two first detection electrodes 13b and 13b and the two second detection electrodes 13d and 13d. In the present embodiment, as shown in FIG. 1, the first detection electrodes 13b and 13b and the second detection electrodes 13d and 13d are arranged corresponding to the vibration axis of the secondary vibration, respectively. All the first detection electrodes 13 b and 13 b and the second detection electrodes 13 d and 13 d are formed outside the center line on the upper surface of the ring-shaped vibrating body 11. Therefore, the sign of the electrical signals of the first detection electrodes 13b and 13b and the second detection electrodes 13d and 13d generated by the secondary vibration excited by the angular velocity is reversed. As shown in FIG. 7, for example, when the ring-shaped vibrating body 11 changes to a vibrating state of the vibrating body 11 a that is vertically elliptical, the position of the first detection electrode 13 b that is disposed outside the center line. the piezoelectric film 40, while extending in the direction of the arrow shown in a 1, the piezoelectric film 40 of the position of the second detection electrode 13d disposed outside the center line is contracted in directions indicated by arrows a 2 Therefore, their electrical signals are reversed. Similarly, if you change the vibration state of the vibrating body 11b of the ring-shaped vibrating body 11 has an elliptical next, the piezoelectric film 40 of the position of the first detection electrodes 13b, while contracts in the direction of the arrow shown in B 1, the piezoelectric film 40 of the position of the second detection electrodes 13d, since extending in the direction of the arrow shown in B 2, also in this case, their electrical signal is reversed.
　ここで、公知の差分回路である演算回路７０において、第１検出電極１３ｂ，１３ｂと第２検出電極１３ｄ，１３ｄの電気信号の差が算出される。その結果、検出信号は第１検出信号又は第２検出信号のいずれか一方のみの場合と比較して約２倍の検出能力を備えることになる。 Here, in the arithmetic circuit 70 which is a known difference circuit, the difference between the electrical signals of the first detection electrodes 13b and 13b and the second detection electrodes 13d and 13d is calculated. As a result, the detection signal has a detection capability that is approximately twice that of either the first detection signal or the second detection signal.
＜第１の実施形態の変形例（１）＞
　図５は、本実施形態におけるもう一つのリング状振動ジャイロ２００の図２に相当する断面図である。本実施形態のリング状振動ジャイロ２００は、第１の実施形態における第２シリコン酸化膜５０の位置を除き、第１の実施形態のリング状振動ジャイロ１００と同一の構成を備える。また、その製造方法は一部を除いて第１の実施形態と同じである。さらに、本実施形態の振動モードは、駆動及び検出に関して第１の実施形態と同様、イン・プレーンのｃｏｓ２θの振動モードである。従って、第１の実施形態と重複する説明は省略される。 <Modification Example (1) of First Embodiment>
FIG. 5 is a cross-sectional view corresponding to FIG. 2 of another ring-shaped vibrating gyroscope 200 in the present embodiment. The ring-shaped vibrating gyroscope 200 of the present embodiment has the same configuration as the ring-shaped vibrating gyroscope 100 of the first embodiment except for the position of the second silicon oxide film 50 in the first embodiment. The manufacturing method is the same as that of the first embodiment except for a part. Furthermore, the vibration mode of the present embodiment is an in-plane cos 2θ vibration mode in the same manner as in the first embodiment regarding driving and detection. Therefore, the description which overlaps with 1st Embodiment is abbreviate | omitted.
　図５に示すとおり、本実施形態の第２シリコン酸化膜５０は、圧電体膜４０と下層金属膜３０との間に形成されている。第１の実施形態の製造工程との違いの１つは、圧電体膜４０が下層金属膜３０上に形成される前に、上述の第２シリコン酸化膜５０がフォトリソグラフィ技術によりパターニングがされている点である。また、本実施形態では、上層金属膜６０と圧電体膜４０上にレジスト膜をパターニングする工程の後、そのレジスト膜をエッチングマスクとして、第２シリコン酸化膜５０、下層金属膜３０、第１シリコン酸化膜２０、及びシリコン基板１０をドライエッチングする。これにより、圧電体膜４０用のエッチングマスクが、その下層の全ての膜又は基板の形状を決めることになるため、製造工程が非常に簡略化される。但し、万一、前述のレジスト膜が、シリコン基板１０のエッチング中に消失した場合であっても、シリコン基板１０に用いられるエッチャントに対するエッチングレートの選択比が有利に働くため、上層金属膜６０又は圧電体膜４０が、その下層に対するエッチングマスクとして機能しうる。 As shown in FIG. 5, the second silicon oxide film 50 of the present embodiment is formed between the piezoelectric film 40 and the lower metal film 30. One difference from the manufacturing process of the first embodiment is that before the piezoelectric film 40 is formed on the lower metal film 30, the second silicon oxide film 50 is patterned by a photolithography technique. It is a point. In this embodiment, after the step of patterning a resist film on the upper metal film 60 and the piezoelectric film 40, the second silicon oxide film 50, the lower metal film 30, and the first silicon are formed using the resist film as an etching mask. The oxide film 20 and the silicon substrate 10 are dry etched. As a result, the etching mask for the piezoelectric film 40 determines the shape of all the underlying films or substrates, so that the manufacturing process is greatly simplified. However, even if the resist film described above disappears during the etching of the silicon substrate 10, the selectivity of the etching rate with respect to the etchant used for the silicon substrate 10 is advantageous, so that the upper metal film 60 or The piezoelectric film 40 can function as an etching mask for the lower layer.
　本実施形態においても、駆動電極１３ａ，１３ａや第１検出電極１３ｂ，１３ｂ等の各電極が形成されている領域には、第２シリコン酸化膜５０が形成されていない。他方、引き出し電極１４の領域では、第２シリコン酸化膜５０及び圧電体膜４０が、上層金属膜６０と下層金属膜３０との間に厚み方向に挟まれている。従って、本実施形態のリング状振動ジャイロ２００も、第１の実施形態と同様の効果が奏される。 Also in this embodiment, the second silicon oxide film 50 is not formed in the region where the electrodes such as the drive electrodes 13a and 13a and the first detection electrodes 13b and 13b are formed. On the other hand, in the region of the extraction electrode 14, the second silicon oxide film 50 and the piezoelectric film 40 are sandwiched between the upper metal film 60 and the lower metal film 30 in the thickness direction. Therefore, the ring-shaped vibrating gyroscope 200 of the present embodiment also has the same effect as that of the first embodiment.
＜第１の実施形態の変形例（２）＞
　図６は、本実施形態におけるもう一つのリング状振動ジャイロ３００の図２に相当する断面図である。本実施形態のリング状振動ジャイロ３００は、第１の実施形態における第２シリコン酸化膜５０のパターニングを除き、第１の実施形態のリング状振動ジャイロ１００と同一の構成を備える。また、その製造方法は一部を除いて第１の実施形態と同じである。さらに、本実施形態の振動モードは、駆動及び検出に関して第１の実施形態と同様、イン・プレーンのｃｏｓ２θの振動モードである。従って、第１の実施形態と重複する説明は省略される。 <Modification (1) of the first embodiment>
FIG. 6 is a cross-sectional view corresponding to FIG. 2 of another ring-shaped vibrating gyroscope 300 according to this embodiment. The ring-shaped vibrating gyroscope 300 of the present embodiment has the same configuration as the ring-shaped vibrating gyroscope 100 of the first embodiment, except for the patterning of the second silicon oxide film 50 in the first embodiment. The manufacturing method is the same as that of the first embodiment except for a part. Furthermore, the vibration mode of the present embodiment is an in-plane cos 2θ vibration mode in the same manner as in the first embodiment regarding driving and detection. Therefore, the description which overlaps with 1st Embodiment is abbreviate | omitted.
　図６に示すとおり、本実施形態の第２シリコン酸化膜５０は、平面視において上層金属膜６０と略同じ形状を有する。第１の実施形態の製造工程との違いは、第２シリコン酸化膜５０のエッチングの際、上層金属膜６０のエッチングの際に用いたレジスト膜の残留分を利用している点である。 As shown in FIG. 6, the second silicon oxide film 50 of the present embodiment has substantially the same shape as the upper metal film 60 in plan view. The difference from the manufacturing process of the first embodiment is that the residual portion of the resist film used in etching the upper metal film 60 is used when the second silicon oxide film 50 is etched.
　本実施形態においても、駆動電極１３ａ，１３ａや第１検出電極１３ｂ，１３ｂ等の各電極が形成されている領域には、第２シリコン酸化膜５０が形成されていない。他方、引き出し電極１４の領域では、第２シリコン酸化膜５０及び圧電体膜４０が、上層金属膜６０と下層金属膜３０との間に厚み方向に挟まれている。従って、本実施形態のリング状振動ジャイロ３００も、第１の実施形態と同様の効果が奏される。 Also in this embodiment, the second silicon oxide film 50 is not formed in the region where the electrodes such as the drive electrodes 13a and 13a and the first detection electrodes 13b and 13b are formed. On the other hand, in the region of the extraction electrode 14, the second silicon oxide film 50 and the piezoelectric film 40 are sandwiched between the upper metal film 60 and the lower metal film 30 in the thickness direction. Therefore, the ring-shaped vibrating gyroscope 300 of this embodiment also has the same effect as that of the first embodiment.
　ところで、上述の各実施形態では、中央線より外側に駆動電極と検出電極が形成されていたが、これに限定されない。駆動電極と検出電極が、中心線よりも内側に配置されていても本発明の効果と同様の効果が奏される。 By the way, in each above-mentioned embodiment, although the drive electrode and the detection electrode were formed outside the center line, it is not limited to this. Even when the drive electrode and the detection electrode are arranged on the inner side of the center line, the same effect as the effect of the present invention can be obtained.
　また、上述の各実施形態は、円環状の振動体を用いた振動ジャイロで説明されているが、円環状の代わりに、多角形状の振動体であってもよい。例えば、正六角形、正八角形、正十二角形、正二十角形等の正多角形状の振動体であっても、本発明の効果と実質的に同様の効果が奏される。また、図８に示すリング状振動ジャイロ４００の八角形状の振動体１１１のような振動体であってもよい。振動体の正面視において点対象形状となる多角形状の振動体が採用されれば、振動体の振動時の安定性の観点で好ましい。また、「円環状」には楕円形状が含まれる。 In addition, although each of the above-described embodiments has been described with a vibrating gyroscope using an annular vibrating body, a polygonal vibrating body may be used instead of the annular ring. For example, even with a regular polygonal vibrator such as a regular hexagon, a regular octagon, a regular dodecagon, and a regular icosahedron, substantially the same effect as the effect of the present invention is exhibited. Moreover, a vibrating body such as the octagonal vibrating body 111 of the ring-shaped vibrating gyroscope 400 shown in FIG. 8 may be used. If a polygonal vibrating body that is a point target shape in a front view of the vibrating body is employed, it is preferable from the viewpoint of stability during vibration of the vibrating body. Further, the “annular shape” includes an elliptical shape.
　また、上述の各実施形態では、引き出し電極１４が、圧電体膜４０と第２シリコン酸化膜５０を上層金属膜６０と下層金属膜３０との間に挟む構成を採用しているが、これに限定されない。他の低誘電率の絶縁膜である、シリコン酸窒化膜、シリコン窒化膜、フルオロカーボン膜、又はポリイミド膜は、シリコン酸化膜の代替物として適用できる。また、前述の低誘電率の各絶縁膜のうち、複数の種類の絶縁膜が適用されても本発明の効果と同様の効果が奏される。 In each of the above-described embodiments, the lead electrode 14 employs a configuration in which the piezoelectric film 40 and the second silicon oxide film 50 are sandwiched between the upper metal film 60 and the lower metal film 30. It is not limited. Other low dielectric constant insulating films, such as silicon oxynitride film, silicon nitride film, fluorocarbon film, or polyimide film, can be applied as an alternative to the silicon oxide film. Further, even when a plurality of types of insulating films are applied among the above-described insulating films having a low dielectric constant, the same effects as the effects of the present invention can be obtained.
　他方、上述の各実施形態の第１シリコン酸化膜の代わりに、例えば、シリコン窒化膜や、シリコン酸窒化膜が形成されていても、本発明の効果と実質的に同様の効果が奏される。 On the other hand, for example, even if a silicon nitride film or a silicon oxynitride film is formed instead of the first silicon oxide film of each of the above-described embodiments, an effect substantially similar to the effect of the present invention is exhibited. .
　さらに、上述の各実施形態では、シリコンを母材とするリング状振動ジャイロが採用されているが、これにも限定されない。例えば、振動ジャイロの母材がシリコンゲルマニウムであってもよい。以上、述べたとおり、各実施形態の他の組合せを含む本発明の範囲内に存在する変形例もまた、特許請求の範囲に含まれるものである。 Furthermore, in each of the embodiments described above, a ring-shaped vibrating gyroscope using silicon as a base material is employed, but the present invention is not limited to this. For example, the base material of the vibration gyro may be silicon germanium. As described above, modifications that exist within the scope of the present invention including other combinations of the embodiments are also included in the scope of the claims.
　本発明は、振動ジャイロとして種々のデバイスの一部として広く適用され得る。 The present invention can be widely applied as a part of various devices as a vibrating gyroscope.

Claims (7)

  1. 　円環状又は多角形状の振動体と、
    　前記振動体を柔軟に支持するとともに固定端を有するレッグ部と、
    　前記振動体上に形成されるとともに上層金属膜及び下層金属膜により圧電体膜を厚み方向に挟む複数の電極と、
    　前記レッグ部上に形成されるとともに、前記上層金属膜及び前記下層金属膜により圧電体膜及び低誘電率の絶縁膜を厚み方向に挟む引き出し電極とを備える
    　振動ジャイロ。     An annular or polygonal vibrator,
    A leg portion that flexibly supports the vibrator and has a fixed end;
    A plurality of electrodes formed on the vibrating body and sandwiching the piezoelectric film between the upper metal film and the lower metal film in the thickness direction;
    A vibration gyro comprising: an extraction electrode formed on the leg portion and sandwiching a piezoelectric film and a low dielectric constant insulating film in the thickness direction by the upper metal film and the lower metal film.
  2. 　前記複数の電極が、前記振動体が配置される面と平行な面内の振動を検出するための検出電極を含み、
    　前記検出電極の前記引き出し電極が、前記レッグ部の上面の外縁と内縁との略中央のみに形成される
    　請求項１に記載の振動ジャイロ。     The plurality of electrodes include a detection electrode for detecting vibration in a plane parallel to a plane on which the vibrating body is disposed;
    The vibrating gyroscope according to claim 1, wherein the extraction electrode of the detection electrode is formed only at a substantially center between an outer edge and an inner edge of the upper surface of the leg portion.
  3. 　前記複数の電極が、前記振動体が配置される面と平行な面内の振動を励起するための駆動電極を含み、
    　前記駆動電極の前記引き出し電極が、前記レッグ部の上面の外縁と内縁との略中央のみに形成される
    　請求項１に記載の振動ジャイロ。     The plurality of electrodes include drive electrodes for exciting vibrations in a plane parallel to a plane on which the vibrating body is disposed,
    The vibrating gyroscope according to claim 1, wherein the extraction electrode of the drive electrode is formed only at a substantially center between an outer edge and an inner edge of the upper surface of the leg portion.
  4. 　前記絶縁膜が、シリコン酸化膜、シリコン酸窒化膜、シリコン窒化膜、フルオロカーボン膜、及びポリイミド膜の群から選ばれる少なくとも１つの絶縁膜である
    　請求項１に記載の振動ジャイロ。     The vibrating gyroscope according to claim 1, wherein the insulating film is at least one insulating film selected from the group consisting of a silicon oxide film, a silicon oxynitride film, a silicon nitride film, a fluorocarbon film, and a polyimide film.
  5. 　振動体と、前記振動体を柔軟に支持するとともに固定端を有するレッグ部とを備える振動ジャイロの製造方法であって、
    　上層金属膜と下層金属膜との間に圧電体膜を厚み方向に挟んだ複数の電極を、円環状又は多角形状の前記振動体の上方にドライエッチングによって形成する工程と、
    　前記上層金属膜と前記下層金属膜との間に前記圧電体膜と低誘電率の絶縁膜を厚み方向に挟んだ前記複数の電極の引き出し電極を、前記レッグ部の上方にドライエッチングによって形成する工程とを有する
    　振動ジャイロの製造方法。     A vibration gyro manufacturing method comprising a vibrating body and a leg portion that flexibly supports the vibrating body and has a fixed end,
    Forming a plurality of electrodes sandwiching a piezoelectric film in the thickness direction between an upper metal film and a lower metal film by dry etching above the annular or polygonal vibrator,
    The lead-out electrodes of the plurality of electrodes, in which the piezoelectric film and the low dielectric constant insulating film are sandwiched in the thickness direction between the upper metal film and the lower metal film, are formed by dry etching above the leg portion. A method for manufacturing a vibrating gyroscope.
  6. 　前記レッグ部の上方に形成される前記圧電体膜上に前記絶縁膜が形成されている
    　請求項５に記載の振動ジャイロの製造方法。     The method for manufacturing a vibrating gyroscope according to claim 5, wherein the insulating film is formed on the piezoelectric film formed above the leg portion.
  7. 　前記引き出し電極は、一部の前記上層金属膜のみ、又はそれに加えて一部の前記絶縁膜をドライエッチングすることにより形成される
    　請求項５又は請求項６に記載の振動ジャイロの製造方法。     The method for manufacturing a vibrating gyroscope according to claim 5, wherein the extraction electrode is formed by dry etching only a part of the upper metal film or a part of the insulating film in addition thereto.
PCT/JP2009/057342 2008-06-23 2009-04-10 Vibrating gyroscope using piezoelectric film and method for manufacturing the same WO2009157246A1 (en)

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