JP5906505B2 - Piezoelectric element frequency measuring method, frequency adjusting method, and piezoelectric element manufacturing method - Google Patents

Description

  The present invention relates to a frequency measuring method and a frequency adjusting method for a piezoelectric element by ion etching, and a method for manufacturing a piezoelectric element.

  Conventionally, a frequency adjustment method of a piezoelectric element by ion etching is known. In this method, plasma is generated inside an ion gun, ions in the plasma are accelerated and emitted by a grid to form an ion beam, and the target piezoelectric element is irradiated with this ion beam for etching. . The resonance frequency of the piezoelectric element rises by etching and approaches the target frequency.

  Here, if the piezoelectric element is irradiated with an ion beam, a so-called charge-up problem occurs in which charged particles are subsequently charged on the piezoelectric element. The frequency of the piezoelectric element in a state where charge-up has occurred is higher than the frequency in a state where there is no charge-up (that is, the actual frequency). Therefore, when charge-up occurs in the piezoelectric element, it is necessary to wait for frequency measurement for the time (for example, about several minutes) until the charged charge is naturally discharged. For this reason, there is a problem that the frequency adjustment process takes time due to the charge-up and the productivity is deteriorated.

  In order to cope with the above problem, Patent Document 1 has a configuration in which, in addition to ion beam irradiation, negatively charged electrons are irradiated to electrically neutralize the potential of the surface of the object to be processed, thereby suppressing charge-up. Disclose. Specifically, a plurality of layers of grids are arranged on the exit surface of the ion gun, and in each grid, electrons for accelerating and extracting negatively charged electrons separately from holes for accelerating and extracting positively charged ions. A port is provided. Then, it is disclosed that by appropriately setting the voltage applied to each grid, the electrons in the plasma reach the object to be processed and the charge is neutralized.

JP 2004-327405 A

  However, according to the configuration of Patent Document 1, there is a problem that the structure of the grid is complicated. Specifically, since it is necessary to provide an electron port separately from the ion extraction hole in each grid, there is a problem that it is difficult to design the arrangement of holes and ports for uniformly extracting the ion beam. The arrangement of the ion beam extraction holes is devised so that the power density of the ion beam has a uniform distribution on the irradiation surface, and providing an electron port makes it difficult to obtain uniform irradiation of the ion beam. is there. In addition, in order to extract electrons more effectively, it is necessary to devise a structure such as a three-layer structure of the grid. Since the structure of the entire grid is complicated, the manufacturing cost of the apparatus increases.

  In addition, it is necessary to optimally design each ion gun with respect to the configuration of ion extraction holes and electron ports for extracting a desired amount of ions and electrons and the voltage applied to each grid. For example, if the amount of extracted electrons is excessive, the object to be processed may be damaged by electron collision, and oscillation may become unstable. Therefore, in order to introduce the technique of this document to various ion guns, different optimum designs are required for the respective ion guns, and there is a problem that it is difficult to provide versatility for countermeasures.

  Therefore, an object of the present invention is to take an effective charge-up measure without changing the structure of a grid or the like in a general ion gun with respect to frequency adjustment of a piezoelectric element by ion etching.

  A first aspect of the present invention is a frequency measurement method for a piezoelectric element using a frequency adjusting device including an ion gun, a shutter that opens and closes between the piezoelectric element to be processed and the ion gun, and a measurement unit that measures the resonance frequency of the piezoelectric element. is there. The frequency measurement method is to turn on the ion gun, open the shutter and irradiate the piezoelectric element with the ion beam, close the shutter and turn off the ion gun, turn off the ion gun, open the shutter, A step of exposing the piezoelectric element to charged particles diffusing from plasma in the ion gun, and a step of measuring the resonance frequency of the piezoelectric element by the measuring means with the ion gun turned off and the shutter closed or opened.

  According to a second aspect of the present invention, there is provided a frequency adjustment method for a piezoelectric element using a frequency adjusting device including an ion gun, a shutter that opens and closes between the piezoelectric element to be processed and the ion gun, and a measurement unit that measures a resonance frequency of the piezoelectric element. is there. The frequency adjustment method includes: (A) a step of turning on the ion gun and irradiating the piezoelectric element with the shutter open, (B) a step of closing the shutter and turning off the ion gun, and (C) an ion gun. And (D) exposing the piezoelectric element to charged particles diffusing from the plasma in the ion gun, and (D) setting the ion gun in the off state and closing the shutter in the open state. A step of measuring a resonance frequency of the piezoelectric element, wherein steps (A) to (D) are repeated a predetermined number of times, and based on the difference between the resonance frequency measured in the step (D) during the repetition step and the target frequency. Then, the ion beam irradiation amount in the step (A) executed thereafter is determined.

  A third aspect of the present invention is a method for manufacturing a piezoelectric element, wherein (A) a process of bringing a piezoelectric element to be processed into a processing tank and disposing the piezoelectric element facing an ion gun, and (B) turning on the ion gun, A step of irradiating the piezoelectric element with an ion beam with the shutter between the ion gun and the ion gun open, (C) a step of closing the shutter and turning off the ion gun, and (D) maintaining the ion gun off and opening the shutter A step of exposing the piezoelectric element to charged particles diffused from plasma in the ion gun, and (E) the resonance frequency of the piezoelectric element is measured by the measuring means with the ion gun turned off and the shutter closed or opened. A manufacturing method provided with the process of carrying out a process and (F) a piezoelectric element from a processing tank.

  In the first to third aspects, the ion gun includes a cathode and an anode for generating a plasma, and a first grid and a second grid for extracting ions from the plasma, and the first grid and the second grid The ion gun was turned off by shutting off the power supply to the grid.

It is a figure which shows the structure of a general frequency adjustment apparatus. It is a figure explaining an example of a piezoelectric element. 3 is a flowchart illustrating a method for manufacturing a piezoelectric element according to an embodiment of the present invention. It is a figure explaining the frequency measuring method of this invention. It is a figure explaining the frequency measuring method of this invention. It is a figure explaining the frequency measuring method of this invention. It is a figure explaining the frequency measuring method of this invention. It is a figure which shows the measurement result by the frequency measuring method by an Example. It is a figure which shows the measurement result by the conventional frequency measuring method. It is a figure which shows the structure of the general frequency adjustment apparatus used with the modification of this invention. It is a flowchart which shows the manufacturing method of the piezoelectric element by a modification. It is a frequency adjustment accuracy of the piezoelectric element manufactured by the method of the present invention. It is a frequency adjustment accuracy of a piezoelectric element manufactured by a conventional method.

Example.
FIG. 1 shows a general frequency adjustment apparatus used in an embodiment of the present invention. The frequency adjusting device includes an ion gun 1, shutters 3-1 to 3-n for opening and closing the crystal resonators 5-1 to 5 -n to be processed with respect to the ion gun 1, and The measuring means 4 for measuring the resonance frequency is provided, and all or a part of these members are included in the processing bath 100. In the following description, the crystal resonators 5-1 to 5-n are collectively referred to as a crystal resonator 5, and the corresponding shutters 3-1 to 3-n are collectively referred to as a shutter 3. Also, probes 41-1 to 41-n described later are collectively referred to as probes 41. It is assumed that the shutter 3-k and the probe 41-k correspond to the crystal resonator 5-k for an arbitrary k of 1 ≦ k ≦ n.

  The ion gun 1 includes a main body 11 that forms a part of the main body of the ion gun, an anode 12 that is formed in a substantially annular shape on the inner periphery of the main body 11, a filament (cathode) 13, a shielding grid 14 having a plurality of ion extraction holes, and an acceleration grid. 15 and a neutralizer 16.

  The main body 11 is powered by the beam power source 21 and is at the same potential as the shielding grid 14. The anode 12 is powered by a discharge power source 22. During the ion beam irradiation, the beam power source is set to about 300 V to 1 kV and the discharge power source is set to about several tens V, and plasma is generated inside the anode 12 by this potential difference. The filament 13 is heated by energization from the filament power source 23, thereby generating thermoelectrons and promoting plasma generation. The acceleration grid 15 is supplied with power from the acceleration power source 24, and a voltage of about −200V to −60V is applied to the ground. Due to the potential difference between the shielding grid 14 and the acceleration grid 15, ions in the plasma are extracted while being accelerated, and the ions exiting the acceleration grid 15 are irradiated in the direction of the arrow in the figure. The neutralizer 16 is supplied with power to the neutralizer power source 25, emits electrons having a negative charge, and performs electrical neutralization in the treatment tank in which irradiation with ions having a positive charge is performed.

  The shutter 3 includes a plurality of shutters 3-1 to 3-n, and opens or shields the crystal resonators 5-1 to 5-n from the ion gun 1 at each timing. That is, the ion beam does not reach the crystal unit 5 when the shutter 3 is in the closed state.

  The measurement means 4 is a measurement probe 41 that is in electrical contact with the electrode of the crystal resonator 5 and transmits a signal, and a frequency measurement that measures the resonance frequency of the crystal resonator 5 based on the signal transmitted by the measurement probe 41. A device 42 (for example, a π circuit and a network analyzer) is provided.

  As for the crystal unit 5, in this embodiment, a tuning fork type crystal unit as shown in FIG. 1B is assumed. A plurality of tuning-fork type crystal resonators 5 are accommodated in the tray 50, and only the etched portion 5a of each crystal resonator 5 is exposed to the ion gun 1 through the opening formed in the tray 50, and the etched portion 5a is irradiated with an ion beam. The In other words, each crystal resonator 5 is masked from the ion gun 1 by the tray 50. Although only one column of crystal resonators is shown in FIG. 1, these are also arranged in the row direction to form a matrix-like arrangement. Further, the processing target is not limited to the individual crystal resonator as shown in FIG. 1B, and may be a sheet substrate on which a plurality of crystal resonators are formed. In the case of a sheet substrate, a tray that individually accommodates crystal resonators is not necessary, and a mask or the like that exposes only the etched portion to the ion gun may be provided separately.

  FIG. 2 is a flowchart showing a method for manufacturing a crystal resonator according to an embodiment of the present invention. The manufacturing method shown in FIG. 2 will be described with reference to FIGS. In the flowchart of FIG. 2, the frequency measurement method of the present invention corresponds to steps S20 to S50, the frequency adjustment method corresponds to steps S20 to S60, and the method for manufacturing a crystal resonator corresponds to steps S10 to S70.

  In step S <b> 10, the crystal resonator 5 is carried into the processing tank 100, arranged on the mask for each column, and arranged opposite to the ion gun 1. At this time, the resonance frequency of each crystal resonator 5 is assumed to be lower than the target frequency. In addition, the processing tank 100 shall be evacuated before and after process S10 (before process S20 at the latest).

  In step S20, as shown in FIG. 3A, the ion gun 1 is turned on (switches S1 and S2 in FIG. 1 are closed), the shutter 3 is opened, and the quartz vibrator 5 is irradiated with an ion beam. In this embodiment, since the plasma is generated from the argon gas, the crystal unit 5 is etched by the irradiated + Ar ions. In step S20, the measurement probe 41 is not in contact with the crystal unit 5, and the frequency is not measured. In particular, when the crystal resonator 5 is of the tuning fork type, the crystal resonator 5 has a large frequency fluctuation due to the temperature of the crystal resonator rising due to the ion beam irradiation, so that an accurate frequency is simultaneously obtained with the ion beam irradiation. Cannot be measured.

  In step S30, as shown in FIG. 3B, the shutter 3 is closed, the ion gun 1 is turned off (the switches S1 and S2 in FIG. 1 are opened), and irradiation (extraction) of the ion beam is stopped. Note that stopping the extraction of the ion beam (the ion gun 1 is off) is not limited to opening the switches S1 and S2, but the output of each power supply may be stopped, and the power supply to the acceleration power supply 24 and the beam power supply 21 is cut off. It only has to be done. At this time, the ion gun 1 is in a floating state. Here, the crystal unit 5 is in a high temperature state immediately after irradiation with the ion beam, but the temperature drops to such an extent that the frequency fluctuation becomes small and frequency measurement is possible in about 1 second. At this time, the crystal unit 5 is positively or negatively charged by + Ar ions or electrons supplied from the neutralizer 16. In the first step S30, the shutters 3-1 to 3-n may be closed simultaneously.

  In step S40, as shown in FIG. 3C, the ion gun 1 is kept off and the shutter 3 is opened. Thereby, plasma is diffused from the inside of the ion gun 1. When charged particles reach the crystal unit 5 from the diffused plasma, the charges charged in the crystal unit 5 are neutralized and the crystal unit 5 is neutralized. In this step S40, neutralization is completed substantially instantaneously (about 1 second). When the crystal unit 5 is negatively charged, positive ions from the plasma inside the ion gun reach the crystal unit 5 for neutralization, and when the crystal unit 5 is positively charged, Electrons from the plasma reach the crystal unit 5 for neutralization. According to the present invention, neutralization is possible with a simple structure regardless of whether the object to be treated is positively or negatively charged.

  In step S50, as shown in FIG. 3D, the ion gun 1 is turned off and the shutter 3 is closed, and the measurement probes 41-1 to 41-n are brought into contact with the crystal resonators 5-1 to 5-n, and the frequency The measuring device 43 measures the resonance frequency of the crystal resonators 5-1 to 5-n. In this embodiment, after the ion gun 1 is maintained in the off state and the shutter 3 is opened, the shutter 3 is closed again in about 0.2 seconds. By closing the shutter 3 immediately after the completion of the neutralization process, the crystal resonator 5 to be processed can be shielded from the thermal effect of the ion gun 1. After completion of the neutralization process, it is desirable to close the shutter 3 in about several seconds. If the processing target is not easily affected by heat, the shutter 3 may be in an open state in step S50.

  In step S52, it is determined whether or not the frequency adjustment count has reached a predetermined number. If the predetermined number has not been reached, the process proceeds to step S54. When the number of adjustments reaches the predetermined number, the process proceeds to step S60, and the frequency adjustment ends.

  In step S54, the resonance frequency (hereinafter referred to as “measurement frequency”) measured in step S50 is compared with the target frequency for each of the crystal resonators 5-1 to 5-n. Based on the difference of the measurement frequency with respect to the target frequency, the irradiation rate of the ion beam, and the like, the additional irradiation amount of the ion beam for each of the crystal resonators 5-1 to 5-n is calculated.

  After step S54, the process returns to step S20. In the second and subsequent steps S20 to S30, the shutters 3-1 to 3-n are opened for a time corresponding to the additional irradiation amount with respect to the crystal resonators 5-1 to 5-n. Accordingly, the timing of closing the shutters 3-1 to 3-n is different as the start of the step S30 (that is, the end of the step S20). If there is a crystal resonator 5-k whose additional irradiation amount calculated in step S54 is 0, the shutter 3-k is kept closed in step S20. Steps S20 to S50 may be repeated about several times. On the other hand, when only one adjustment is required for all the crystal resonators 5, the steps S52 and S54 are omitted, and the process may be shifted from the step S50 to the step S60.

  After steps S <b> 10 to S <b> 60 are repeated for each row of crystal resonators, the crystal resonator 5 is unloaded from the processing bath 100 in step 70. In step S70, the processing tank 100 may be returned to the atmosphere, or the crystal unit 5 may be carried out by a separate transport mechanism while maintaining a vacuum state. When a sheet substrate is used, each crystal resonator 5 may be separated from the frame after unloading.

  In FIG. 4A, the measurement result by the frequency measurement (process S20-S50) of an Example is shown. The horizontal axis represents time, and the vertical axis represents the ratio of one frequency adjustment amount ΔF to the frequency F before adjustment. In this embodiment, the target ΔF / F is 150 ppm. t0 indicates the timing when the ion gun 1 is turned on and the shutter 3 is opened and the ion beam irradiation is started in step S20. t1 indicates the timing when the shutter 3 is closed and the ion gun 1 is turned off in step S30. The time from t0 to t1 is several seconds. The crystal resonator 5 is naturally cooled from the time when the ion beam irradiation is stopped at t1. t2 indicates the timing at which the temperature of the crystal unit 5 is sufficiently lowered and the influence of heat is eliminated. Although not shown in the figure, ΔF / F may swing to the negative side immediately after t1 due to the influence of irradiation heat. The time required from t1 to t2 is about 1 second. t3 indicates the timing when the shutter 3 is opened in step S40. Step S40 is completed instantaneously, and measurement of the frequency in step S50 is performed at an arbitrary time immediately after t3.

  In this embodiment, the timing (t3) at which the process S40 is started after about 10 seconds from the time t1 is set, but the time at which the process S40 is started may be between t1 and t2. However, the frequency measurement in step S50 needs to be performed after t2, that is, after the crystal unit 5 is sufficiently cooled.

  FIG. 4B shows a measurement result by frequency measurement of the conventional example (without step S40). As shown in the measurement results, it can be seen that it takes several minutes from the end of the ion beam irradiation until the neutralization is almost completed. Therefore, when step S40 is not included, it has been necessary to wait about several minutes from the end of ion beam irradiation for the start of frequency measurement. However, by including step S40 as in the present invention, this waiting time is greatly increased. It can be shortened. Therefore, in the present invention, the time from the end of ion beam irradiation in step S30 to the start of frequency measurement in step S50 is theoretically reduced to a time equal to the cooling time of the crystal unit 5. Can do.

  In addition, regarding static elimination by natural discharge without using step S40, it is known that there is a variation in the static elimination speed for each crystal resonator. Therefore, when neutralization by natural discharge is used, even if frequency measurement is performed by applying a predetermined waiting time and a predetermined correction coefficient after ion beam irradiation, measurement frequency variations among crystal resonators occur. On the other hand, according to the present embodiment using the step S40, the frequency measurement is performed after the static elimination is completed, so the variation in the measurement frequency between the crystal resonators is very small, and it is necessary to apply a correction coefficient to the frequency measurement. Nor.

  Thus, according to the present invention, it is possible to easily take a charge-up measure using a general frequency adjustment device. In other words, without changing the structure of the frequency adjusting device, the charge-up countermeasure can be taken only by changing the opening / closing operation of the shutter 3 (and, in some cases, the power supply and shut-off operation to the ion gun 1) from the existing frequency adjusting device. This is advantageous because it can be done without additional cost or design time. Further, since the present invention does not require structural changes for charge-up countermeasures, it can be easily introduced into various frequency adjustment devices, and is highly versatile.

Modified example.
In the above embodiment, an example in which the frequency of a plurality of tuning fork type crystal resonators is adjusted using a so-called rectangular ion gun (one having an ion beam in a band shape) is shown. An example of adjusting the frequency of a square crystal resonator using a linear shape) is shown.

  FIG. 5 shows a frequency adjusting device used in this modification. As in the case of FIG. 1, the ion gun 6, the shutter 7 that opens and closes the square crystal resonator 9 to be processed with respect to the ion gun 6, and the measurement unit 8 that measures the resonance frequency of the crystal resonator 9 are provided. All or part of each member is included in the treatment tank 200. Although the power supply system to the ion gun 6 is not shown, it is assumed that power is appropriately supplied and cut off as in FIG. The configuration of the frequency adjusting device itself is a general one and is the same as that of the above embodiment except that the ion beam is linear. Therefore, detailed description thereof is omitted. FIG. 6 shows a flowchart of a method for manufacturing a crystal resonator according to this modification.

  In step S <b> 110, the crystal resonator 9 is disposed to face the ion gun 6 through the mask 90. At this time, it is assumed that the resonance frequency of each crystal resonator 9 is lower than the target frequency. In addition, the processing tank 200 shall be evacuated before and after process S110 (before process S120 at the latest).

  In step S120, the ion gun 6 is turned on, the shutter 7 is opened, and the ion beam is irradiated to the crystal unit 9 (see FIG. 3A). For example, if the plasma is generated from argon gas as in the embodiment, the crystal unit 9 is etched by + Ar ions irradiated. In this step, the measurement probe 81 is in contact with the crystal unit 5, and the frequency measurement is performed in real time by the π circuit 82 and the network analyzer 83. In particular, since the crystal unit 9 is of a square type, it is not easily affected by heat during ion beam irradiation. Therefore, an accurate value can be obtained even if the frequency is measured simultaneously with the ion beam irradiation.

  In step S130, the shutter 7 is closed, the ion gun 6 is turned off, and irradiation of the ion beam to the crystal unit 9 is stopped (see FIG. 3B). Here, the crystal unit 9 is charged.

  In step S140, the shutter 7 is opened while the ion gun 6 is kept off. Thereby, charged particles are diffused from the plasma inside the ion gun 6 (see FIG. 3C). When the diffused charged particles reach the crystal unit 9, the charges charged in the crystal unit 9 are neutralized, and the crystal unit 9 is neutralized. In this step S140, the neutralization is completed substantially instantaneously (about 1 second).

  Here, since the step S140 of opening the shutter 7 is started immediately after the step S130 of closing the shutter 7, the operation of closing the shutter 7 may theoretically be omitted. In order to accurately control the ion beam irradiation amount, it is desirable to close the shutter 7 in step S130.

  In step S150, the ion gun 6 is turned off and the shutter 7 is closed, the measurement probe 81 is brought into contact with the crystal resonator 9, and the resonance frequency of the crystal resonator 9 is measured by the π circuit 82 and the network analyzer 83 ( (See FIG. 3D). In step S150, the shutter 7 may be in an open state.

  In step S155, the resonance frequency (measurement frequency) measured in step S150 is compared with the target frequency. If the measurement frequency is within the predetermined range of the target frequency, the process proceeds to step S160, and the frequency adjustment ends. If the measurement frequency is not within the predetermined range of the target frequency, the process returns to step S120.

  In the second and subsequent steps S120, the additional irradiation amount of the ion beam to the crystal unit 9 may be determined based on the difference in the measurement frequency with respect to the target frequency, the irradiation rate of the ion beam, or the like. Steps S120 to S150 may be repeated with the given irradiation amount. In addition, said predetermined irradiation amount is good also as a fixed amount irrespective of the frequency | count of process S120, and is good also as an amount which decreases gradually as the frequency | count increases. As in the above embodiment, when only one frequency adjustment is required, step S155 may be omitted, and the process may be shifted from step S150 to step S160.

  After steps S110 to S160 are repeated for each crystal resonator to be processed, the crystal resonator 9 is unloaded from the processing bath 200 in step S170. In step S170, the processing tank 200 may be returned to the atmosphere, or the crystal unit 9 may be carried out by a separate transport mechanism while maintaining a vacuum state.

  Also in this modification, the same effect as the said Example can be acquired. In other words, without changing the structure of the frequency adjusting device, the charge-up countermeasure can be taken only by changing the opening / closing operation of the shutter 7 (and, in some cases, the power supply and shut-off operation to the ion gun 6) from the existing frequency adjusting device. This is advantageous because it can be done without additional cost or design time. In addition, since this modification also does not require structural changes for charge-up countermeasures, it can be easily introduced into various frequency adjusting devices and has high versatility.

  FIG. 7A shows the frequency adjustment accuracy of a tuning fork type crystal resonator manufactured by the method of the present invention. From the figure, it can be seen that 95% or more of the crystal resonators are frequency adjusted within a range of ± 5 ppm of the target frequency F. On the other hand, FIG. 7B shows the frequency adjustment accuracy of a tuning fork type crystal resonator manufactured by a conventional method. Here, in the conventional method, electrons are supplied by the neutralizer 16, but charge-up measures after beam irradiation is stopped are not implemented. The configuration in which electrons are supplied from the electron port simultaneously with etching by positive ion beam irradiation as in Patent Document 1 has the same function as the neutralizer 16. From FIG. 7B, it can be seen that the variation in the frequency adjustment accuracy is large only with the configuration in which electrons are supplied from the neutralizer 16 simultaneously with the ion beam irradiation. According to the present invention, it is possible to remarkably improve the frequency measurement accuracy by adding a step of neutralizing the processing target charged when the ion beam irradiation is stopped and then measuring the frequency.

  In addition, although this invention was demonstrated using the said Example and modification, this invention can be changed as follows. For example, in the above-described embodiments and modifications, the production of tuning fork type and square crystal resonators is exemplified, but the present invention can also be applied to other types of piezoelectric elements. Furthermore, the present invention can be applied not only to a crystal resonator frequency adjustment device but also to various devices in which charge-up in ion etching is a problem.

1,6. Ion gun 3,7. Shutters 4 and 8. Measuring means 5, 9. Crystal resonator 11. Cathode 12. Anode 13. Filament 14. Acceleration grid 15. Shielding grid 16. Neutralizer 21. Beam power supply 22. Discharge power source 23. Filament power supply 24. Acceleration power supply 25. Neutralizer power supply 41, 81. Probe 42. Frequency measuring instrument 50. Tray 82. π circuit 83. Network analyzer 90. Mask 100, 200. Processing tank S1, S2. switch

Claims (6)

A method for measuring the frequency of a piezoelectric element by a frequency adjusting device comprising an ion gun, a shutter that opens and closes between the piezoelectric element to be processed and the ion gun, and a measuring unit that measures a resonance frequency of the piezoelectric element,
Turning the ion gun on, opening the shutter and irradiating the piezoelectric element with an ion beam;
Closing the shutter and turning off the ion gun;
Turning the ion gun off and opening the shutter to expose the piezoelectric element to charged particles diffusing from plasma in the ion gun; and turning off the ion gun and closing or opening the shutter As a frequency measurement method comprising a step of measuring a resonance frequency of the piezoelectric element by the measurement means. The frequency measurement method according to claim 1, wherein the ion gun comprises a cathode and an anode for generating a plasma, and a first grid and a second grid for extracting ions from the plasma,
A frequency measurement method for turning off the ion gun by interrupting power supply to the first grid and the second grid. A frequency adjustment method of a piezoelectric element by a frequency adjustment device comprising an ion gun, a shutter that opens and closes between the piezoelectric element to be processed and the ion gun, and a measurement unit that measures a resonance frequency of the piezoelectric element,
(A) The ion gun is turned on, the shutter is opened, and the piezoelectric element is irradiated with an ion beam;
(B) a step of closing the shutter and turning off the ion gun;
(C) exposing the piezoelectric element to charged particles diffusing from plasma in the ion gun with the ion gun turned off and the shutter opened; and (D) the ion gun turned off and the shutter opened. A step of measuring the resonance frequency of the piezoelectric element by the measurement means as a closed state or an open state is provided, and the step (D) is repeated a predetermined number of times, and the step (D) is repeated during the repetition step. The frequency adjustment method in which the ion beam dose in the step (A) executed thereafter is determined based on the difference between the resonance frequency measured in step 1 and the target frequency. The frequency adjusting method according to claim 3, wherein the ion gun includes a cathode and an anode for generating a plasma, and a first grid and a second grid for extracting ions from the plasma,
A frequency adjustment method for turning off the ion gun by interrupting power supply to the first grid and the second grid. A method for manufacturing a piezoelectric element, comprising:
(A) A process of bringing a piezoelectric element to be processed into a processing tank and disposing it in opposition to an ion gun,
(B) turning on the ion gun, opening a shutter between the piezoelectric element and the ion gun, and irradiating the piezoelectric element with an ion beam;
(C) closing the shutter and turning off the ion gun;
(D) maintaining the ion gun in an off state, opening the shutter, and exposing the piezoelectric element to charged particles diffusing from plasma in the ion gun;
(E) a step of measuring the resonance frequency of the piezoelectric element by measurement means with the ion gun turned off and the shutter closed or open; and (F) carrying the piezoelectric element out of the processing tank. Production method. 6. The manufacturing method according to claim 5, wherein the ion gun includes a cathode and an anode for generating a plasma, and a first grid and a second grid for extracting ions from the plasma,
The manufacturing method which makes the said ion gun an OFF state by interrupting | blocking the electric power feeding to a said 1st grid and a said 2nd grid.

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