JP2010183137A - Crystal vibration piece and method of manufacturing the same, vibrator, oscillator, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact crystal vibration piece having stable frequency characteristics, to provide a method of manufacturing the crystal vibration piece, to provide a vibrator, to provide an oscillator, and to provide electronic equipment. <P>SOLUTION: The tuning fork crystal vibration piece 1 includes: a vibration reed 102 having a base 110 and a pair of tuning fork arms 121, 122 extended from the base 110 parallel mutually; excitation electrodes 123a, 124a formed on both the main surfaces of the tuning fork arms 121, 122; and drive electrodes 123b, 124b formed on both the sides of the tuning fork arms 121, 122. Modified sections 151, 152 extended along the tuning fork arms 121, 122 and have a texture structure differing from that of crystal are formed over the entire longitudinal direction of at least the tuning fork arms 121, 122. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a quartz crystal resonator element, a method for manufacturing the same, a vibrator, an oscillator, and an electronic device.

  Conventionally, crystal resonators have been adopted as frequency control elements in oscillation circuits of various electronic devices. In particular, a tuning fork resonator is used as a power-saving crystal resonator that is small, hard to break, and vibrates accurately. Such a tuning fork vibrator is built in various electronic devices including a clock as a clock source together with an oscillation circuit, and vibrates due to an inverse piezoelectric phenomenon with an applied voltage.

In recent years, there has been an increasing demand for miniaturization of tuning fork vibrators in response to miniaturization of various electronic devices. However, when the tuning fork vibrator is downsized, there is a problem that the Q value is remarkably lowered.
In view of this, for example, a structure has been proposed in which grooves are provided on both main surfaces of a pair of vibrating arms of a vibrating piece to suppress a decrease in Q value due to thermoelasticity (Patent Documents 1 and 2).

Japanese Utility Model Publication No. 2-3322 JP 2002-280870 A

  However, when the resonator element is further reduced in size, there is a problem in that a decrease in the Q value cannot be suppressed only by forming a groove. Since the oscillation becomes more stable as the Q value is larger, there is a demand for a structure that can obtain an appropriate Q value even when the size is reduced.

  The present invention has been made in view of the above problems of the prior art, and aims to provide a quartz crystal resonator element having a small and stable frequency characteristic, a manufacturing method thereof, a vibrator, an oscillator, and an electronic device. Yes.

  In order to solve the above problems, a quartz crystal resonator element according to the present invention is formed on a resonator element body having a base portion and a pair of vibrating arm portions extending in parallel from the base portion, and both main surfaces of the vibrating arm portion. A quartz crystal vibrating piece having excitation electrodes and drive electrodes formed on both side surfaces of the vibrating arm portion, wherein the altered arm portion extending along the vibrating arm portion and having a tissue structure different from that of the quartz crystal is at least the vibrating arm portion. It is formed over the entire length direction.

  According to the present invention, the altered portion having a tissue structure different from that of the quartz is formed over at least the entire length direction of the vibrating arm portion, so that Q is affected by the influence of thermoelasticity or the like due to the vibration of the vibrating arm portion. It can prevent that a value falls. Thereby, even if it is small, an appropriate Q value can be obtained, and a high-performance crystal vibrating piece with a stable oscillation frequency can be obtained.

In addition, the altered portion is preferably formed from the tip of the vibrating arm portion to the end of the base portion.
According to the present invention, since the altered portion is formed from the tip of the vibrating arm portion to the end portion of the base portion, it is possible to minimize the influence of thermoelasticity caused by vibration, and the characteristics of the quartz crystal vibrating piece It is possible to more effectively prevent the deterioration.

Further, the altered portion is preferably in a state where at least amorphous, polycrystalline, quartz, cavities and the like are mixed.
According to the present invention, the altered portion is in a state in which at least amorphous, polycrystalline, quartz, cavities, and the like are mixed, so that the thermal conductivity and the coefficient of thermal expansion are lower than quartz, and the decrease in the Q value is efficiently suppressed. It is possible.

Further, it is preferable that the altered portion is located in the center in the width direction of the vibrating arm portion, and a single crystal portion exists on both sides of the altered portion in the width direction.
According to the present invention, by providing the altered portion so that the single crystal portion (quartz) exists on both sides in the width direction of the altered portion, the performance deterioration preventing function is ensured while ensuring the piezoelectricity and mechanical strength of the quartz crystal vibrating piece. Therefore, reliability can be improved.

Moreover, it is preferable that the altered portion is formed so as to penetrate the vibrating arm portion in the thickness direction.
According to the present invention, since the altered portion is formed across the thickness direction of the vibrating arm portion, the thermal conductivity and the coefficient of thermal expansion can be further reduced, and the Q value improving effect is improved.

The width of the altered portion is preferably in the range of 10% to 80% with respect to the width of the vibrating arm portion.
According to the present invention, when the width of the altered portion is less than 10% with respect to the width of the vibrating arm portion, the effect of improving the Q value cannot be expected so much because the property is substantially the same as that of quartz. On the other hand, if it is 80% or more, there is a possibility that the piezoelectric function cannot be secured or the mechanical strength is lowered. Therefore, by setting the width of the vibrating arm within the above range, it is possible to improve the Q value as compared with the conventional technique while ensuring the piezoelectric function and the mechanical strength.

Moreover, it is preferable that the groove | channel which extends along the length direction of a vibrating arm part is formed in both the main surfaces of a vibrating arm part, respectively.
According to the present invention, the vibration loss of the vibrating arm portion can be reduced, and the vibration efficiency can be improved.

  In order to solve the above problems, a method for manufacturing a crystal resonator according to the present invention includes a resonator element body having a base portion and a pair of vibrating arm portions extending in parallel from the base portion, and both main surfaces of the vibrating arm portions. A method of manufacturing a quartz crystal vibrating piece having an excitation electrode formed on the substrate and drive electrodes formed on both side surfaces of the vibrating arm, the step of forming the base and the vibrating arm by etching the quartz substrate; Irradiating a laser along the vibrating arm, forming a denatured portion having a tissue structure different from quartz over at least the entire length of the vibrating arm, and forming an excitation electrode and a drive electrode; Have

  According to the present invention, at least the entire length of the vibrating arm portion is irradiated with a laser to form an altered portion having a tissue structure different from that of quartz, so the influence of thermoelasticity and the like due to vibration of the vibrating arm portion. Therefore, it is possible to prevent the Q value from being lowered. Thereby, even if it is small, an appropriate Q value can be obtained, and a high-performance crystal vibrating piece with a stable oscillation frequency can be obtained.

Further, it is preferable that the altered portion is formed by continuously irradiating a laser from the tip of the vibrating arm portion to the end portion of the base portion.
According to the present invention, the altered portion can be formed from the tip end of the vibrating arm portion to the end portion of the base portion.

The laser is preferably a femtosecond pulse laser.
According to the present invention, an altered portion can be reliably formed on a transmissive quartz substrate. In addition, there is no risk of damage around the altered portion (laser irradiation region). Further, it is possible to form an altered portion in a state where at least amorphous, polycrystalline, quartz, cavities and the like are mixed.

Moreover, it is preferable that the output of a laser shall be 300 nJ or more and less than 500 nJ.
According to the present invention, since the altered portion can be visually confirmed, the altered portion can be reliably and easily formed in a predetermined region. In addition, it is possible to prevent the quartz substrate from being cracked after the laser irradiation.

Moreover, it is preferable to have the process of forming a groove | channel in both the main surfaces of a vibrating arm part before the process of forming an alteration part.
According to the present invention, it is possible to improve vibration efficiency by forming grooves on both main surfaces of the vibrating arm portion.

The vibrator according to the present invention includes the above-described quartz crystal resonator element housed in a package.
According to the present invention, since the quartz crystal resonator element having the altered portion is provided, stable frequency oscillation characteristics can be ensured even if the size is reduced, and the reliability as a vibrator is improved.

The oscillator according to the present invention includes the crystal resonator element described above and an integrated circuit housed in a package.
According to the present invention, since the quartz crystal resonator element having the altered portion is provided, stable frequency oscillation characteristics can be ensured even when the size is reduced, and the reliability as an oscillator is improved.

An electronic apparatus according to the present invention includes an oscillator in which the crystal resonator element described above is housed in a package, and the oscillator is connected to a control unit for use.
According to the present invention, since the quartz crystal resonator element having the altered portion is provided, stable frequency oscillation characteristics can be ensured even when the size is reduced, and the reliability as an electric device is improved.

The top view which shows the tuning fork type crystal vibrating piece in 1st Embodiment. E'-E sectional drawing of FIG. FIG. 3 is a plan view showing a resonator element main body according to the first embodiment. The manufacturing process figure of the tuning fork type crystal vibrating piece in 1st Embodiment. The manufacturing process figure of the tuning fork type crystal vibrating piece in 1st Embodiment. The schematic block diagram of a laser irradiation apparatus. The top view which shows the tuning fork type crystal vibrating piece in 2nd Embodiment. F'-F sectional drawing of FIG. The top view which shows the vibration piece main body in 2nd Embodiment. The manufacturing process figure of the tuning fork type crystal vibrating piece in 2nd Embodiment. The manufacturing process figure of the tuning fork type crystal vibrating piece in 2nd Embodiment. The figure which shows the ceramic package tuning fork type vibrator which is a vibrator concerning the present invention. The figure which shows the tuning fork crystal oscillator which is an oscillator which concerns on this invention. The figure which shows the cylinder type tuning fork vibrator which is a vibrator | oscillator which concerns on this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

(First embodiment of tuning-fork type crystal vibrating piece)
1 is a diagram showing a schematic configuration of a tuning-fork type crystal vibrating piece 1 which is a quartz crystal vibrating piece according to the first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line E′-E of FIG. 1, and FIG. 3 is a plan view showing a piece body 102. FIG.
As shown in FIGS. 1 and 2, the tuning fork type crystal vibrating piece 1 includes a base portion 110 and a pair of tuning fork arms 121 and 122 (vibrating arm portions) extending from the base portion 110 upward (y direction) in the drawing. The vibration piece main body 102 provided with the above. The tuning fork type crystal vibrating piece 1 in the present embodiment is a small vibrating piece that transmits at 32.768 kHz, for example, the width W of the tuning fork arms 121 and 122 is extremely small, 50 μm to 100 μm, and the thickness t is 50 μm to 100 μm. .

  The base 110 functions as a mounting area when the tuning fork type crystal vibrating piece 1 is fixed to a package or the like, for example, and base electrodes 125a and 125a are provided on the main surface thereof. The base electrode 125a is a thin film electrode for electrical continuity with an external component, and is formed of a conductive material, for example, a metal layer such as Au, Al, Cu, Cr, or a thin film in which these are laminated. ing.

  The tuning fork arm 121 has excitation electrodes 123a and 123a oppositely arranged on both main surfaces thereof, and drive electrodes 123b and 123b oppositely arranged on both side surfaces thereof. Excitation electrodes 124a and 124a are disposed opposite to both main surfaces of the tuning fork arm 122, and drive electrodes 124b and 124b are disposed opposite to each other on both sides. The excitation electrodes 123a and 124a and the drive electrodes 123b and 124b are made of the same material as the base electrode 125a described above. Furthermore, an electrode 125b for supplying power is also formed at the tip of each tuning fork arm 121, 122.

  In each tuning fork arm 121, 122, the excitation voltage applied to the excitation electrodes 123a, 124b has the same phase, and the drive voltage applied to the drive electrodes 123b, 124a has an opposite phase to the excitation electrodes 123a, 124b. Wired to the negative drive circuit.

  Inside the tuning fork type crystal vibrating piece 1 in the present embodiment, altered portions 151 and 152 are partially formed as shown in FIGS. These altered portions 151 and 152 are formed in the crystal substrate irradiated with the laser in the quartz substrate, and are regions that do not contribute much to the piezoelectric vibration of the tuning fork type crystal vibrating piece 1, and each tuning fork arm 121 and 122. Each is formed in a line shape over the whole extending direction.

  Specifically, the altered portions 151 and 152 are located in the center in the width direction (x direction) of the tuning fork arms 121 and 122, and the length of each tuning fork arm 121 and 122 extends from the tip of the tuning fork arms 121 and 122 to the end of the base 110. It extends in the vertical direction.

  Here, the altered portions 151 and 152 in this embodiment are non-crystalline states that are recrystallized after the portions irradiated with the laser are melted, and portions where at least amorphous, polycrystalline, quartz, cavities, and the like are mixed. This refers to the state in which the crystallinity of the crystal has changed due to the formation of minute cavities and holes. In other words, the altered portions 151 and 152 have a structure different from that of quartz because, for example, voids and single crystals are partially included.

  As polycrystallization progresses due to the irradiation of the laser, it is expected that the thermal conductivity is lowered at the same time as the thermal conductivity is lowered. In general, it is clear that amorphous thermal conductivity and thermal expansion coefficient are naturally lower than single crystals. For this reason, it can be said that the fact that the thermal conductivity and the thermal expansion coefficient decrease as the crystallization and the amorphization progress clearly shows the difference from the single crystal. Then, the result of investigating the characteristics of the amorphous, that is, the characteristics of the altered portions 151 and 152 in the present embodiment is shown in Table 1 to clarify the difference from the single crystal.

Table 1 shows the thermal expansion coefficient (ppm / K) and elastic modulus (N / N) of the altered portion and the single crystal portion (quartz single crystal) in this embodiment in which the crystallinity of the quartz crystal was changed by laser irradiation. Evaluations of m ² ), density (g / cm ³ ), heat capacity (J / Kg), and thermal conductivity (W / mK) are shown.

表１に示すように、単結晶部と変質部との比較において、弾性率、密度および熱容量に大きな違いは見受けられないが、熱膨張係数、熱伝導率に関しては単結晶部に比べて変質部の値が大幅に低下しており物性が大きく変化している。単結晶部の熱膨張数が１３．７ｐｐｍ／Ｋであるのに対して、変質部の熱膨張係数は０．５６ｐｐｍ／Ｋ程度である。一方、単結晶部の熱伝導率が１０Ｗ／ｍＫであるのに対して、変質部の熱伝導率は１．４Ｗ／ｍＫである。このことから、本実施形態における変質部は、レーザーが照射されたことによって水晶の結晶構造が変質してアモルファス化したと考えられる。

As shown in Table 1, in the comparison between the single crystal part and the altered part, there is no significant difference in the elastic modulus, density and heat capacity, but the altered part compared to the single crystal part in terms of thermal expansion coefficient and thermal conductivity. The value of is drastically reduced and the physical properties are greatly changed. The single crystal part has a thermal expansion coefficient of 13.7 ppm / K, whereas the altered part has a thermal expansion coefficient of about 0.56 ppm / K. On the other hand, the thermal conductivity of the single crystal part is 10 W / mK, while the thermal conductivity of the altered part is 1.4 W / mK. From this, it is considered that the altered portion in the present embodiment has become amorphous due to alteration of the crystal structure of the crystal due to the laser irradiation.

  In the present embodiment, the altered portions 151 and 152 are not formed over the entire width of the tuning fork arms 121 and 122 as described above, but the crystallinity of the crystal is changed on both sides of the altered portions 151 and 152. Since there are no side portions 121a and 122a (single crystal portions), the piezoelectric function and the mechanical strength are ensured even if the altered portions 151 and 152 having the above characteristics are provided.

  As shown in FIG. 2, the width W1 of the altered portions 151 and 152 in this embodiment is desirably formed within a range of 30% to 50% of the width W of the tuning fork arms 121 and 122. For example, if the width W1 of the altered portions 151 and 152 is too small, the heat conduction is not much different from that of quartz. Conversely, if the altered portions 151 and 152 are provided up to the side surfaces of the tuning fork arms 121 and 122, the piezoelectricity is lost. . Further, if the width W1 of the altered portions 151 and 152 is too large, cracks may occur in the tuning fork arms 121 and 122. Therefore, the width W1 of the altered portions 151 and 152 depends on the width W of the tuning fork arms 121 and 122. It is made to form within the said range. It is desirable to set the range in consideration of the temperature characteristics of the resonator element and the stability of the frequency.

  The tuning-fork type crystal vibrating piece 1 having such a configuration generates bending vibrations due to electric fields opposite to each other generated between both main surfaces and both side surfaces of the tuning-fork arms 121 and 122, and finally generates tuning-fork vibrations. It will be. For example, in the tuning fork arm 121, when an electric field in the x direction from the center toward both sides is applied, if the right portion extends in the y direction in FIG. 2, the left portion contracts and faces the tuning fork arm 122. Displace in the direction.

  On the other hand, in the tuning fork arm 122, when an electric field in the x direction is applied in a direction from both side surfaces toward the central portion, when the left portion in FIG. 2 extends in the y direction, the right portion contracts and the other tuning fork arm It is displaced in a direction facing 121. Further, when a voltage that reverses the electric field to the above case is applied to the electrodes 123a, 124a, 123b, and 124b, the tuning fork arms 121 and 122 vibrate away from each other, and the pair of tuning fork arms 121 and 122 It vibrates in the opposite horizontal directions, resulting in tuning fork vibration.

  However, when the tuning fork type quartz vibrating piece is downsized, the flow of heat inside the quartz accompanying the vibration of the tuning fork arms 121 and 122 inhibits the vibration, and the characteristic, that is, the Q of the tuning fork type quartz vibrating piece 1 is obtained. There was a risk that the value would be significantly reduced. The Q value of the tuning-fork type crystal vibrating piece 1 is determined by the thermal conductivity and the thermal expansion coefficient, and it is desirable that the Q value is 10,000 or more, and a measure for improving the Q value is required.

  For this reason, in this embodiment, by providing the altered portions 151 and 152 in which the crystal structure of the crystal is altered inside the tuning fork type quartz vibrating piece 1, it is possible to greatly improve the decrease in the Q value accompanying the downsizing. . That is, the altered portions 151 and 152 that have been altered by laser irradiation have a rough crystal structure and are thus in a rough state, so that heat conduction is cut off and the thermal expansion coefficient is reduced (Table 1). In this way, by forming the altered portions 151 and 152 inside, it is possible to minimize the influence of thermoelasticity and the like due to vibration, and to suppress the influence of heat transfer due to vibration. Therefore, the tuning-fork type crystal vibrating piece 1 having the altered portions 151 and 152 has an improved Q value and a stable oscillation frequency, and is small and high-performance. Further, even when the size is further reduced, the Q value can be increased.

  The tuning-fork type crystal vibrating piece 1 according to the present embodiment is configured as described above. Hereinafter, the process diagram shown in FIGS. 4 and 5 and the laser irradiation apparatus 20 shown in FIG. The description will be given with reference.

  First, a crystal substrate 30 as shown in FIG. The quartz substrate 30 is cut out from a quartz block into a wafer shape and polished to form a flat plate shape. A protective film 31 is formed on the surface of the quartz substrate 30 by laminating a Cr film and an Au film in this order.

  Next, a resist Re is coated on the surface of the protective film 31 as shown in FIG. 4B, and a resist mask 32 patterned in a desired shape as shown in FIG. 4C is formed through a photolithography process. The resist mask 32 corresponds to the outer shape of the tuning fork type crystal vibrating piece.

  Next, as shown in FIG. 4D, the protective film 31 is etched in the order of the Au film and the Cr film in accordance with the shape of the resist mask 32. After patterning the protective film 31, as shown in FIG. 5E, the base 110 (FIG. 3) and the tuning fork arms 121 and 122 are etched by etching the quartz substrate 30 into the outer shape of the tuning fork type quartz vibrating piece. Thus, the vibrating piece main body 102 is obtained. Then, the resonator element main body 102 is set in the laser irradiation apparatus 20 shown in FIG.

  As shown in FIG. 6, the laser irradiation apparatus 20 used in the manufacturing method of the present embodiment is configured based on a laser light source 23, an optical system, and a multi-axis stage 28. Laser light emitted from the laser light source 23 is emitted from the laser irradiation apparatus 20. Then, the light is incident on the objective lens 27 through the half mirror 26 and irradiated onto the quartz substrate 30.

  Then, femtosecond laser irradiation is performed on a predetermined area of the resonator element main body 102 (tuning fork arms 121 and 122) placed on the multi-axis stage 28 of the irradiation apparatus 20, and laser irradiation is performed as shown in FIG. 5 (f). Altered portions 151 and 152 are formed inside the portion of the crystal. When the laser beam is irradiated, the crystal energy of the quartz substrate 30 is generated by the thermal energy, and the altered portions 151 and 152 are formed.

Here, the femtosecond laser is a pulse laser having a pulse width in the order of femtoseconds (fs: ^10-15 seconds), and high energy concentrates on the irradiated part in a very short time, so that heat conduction occurs around the laser. Processing proceeds in advance, and processing of only the light collecting region is induced. For this reason, there is almost no effect on the periphery of the irradiated region. In addition, by using a femtosecond laser, it is possible to irradiate light to a transparent member such as quartz.

  In this embodiment, for example, a titanium-sapphire laser having a wavelength of 800 nm, a pulse width of 130 fs, and a frequency of 5 kHz is used as the femtosecond laser. The condensing spot diameter of the laser beam is about 0.5 to 1 μm.

  The laser output is 150 nJ to 450 nJ, preferably 200 nJ to 400 nJ, and is set to 300 nJ in this embodiment. When the laser output is set to 100 nJ, the altered portion cannot be visually confirmed. By setting the output to 300 nJ, the altered portion can be visually confirmed. In addition, when the output is increased to 500 nJ, the deteriorated portion can be visually confirmed, but a crack occurs in the moving direction of the multi-axis stage 28.

  Scanning of the irradiation position of the laser beam on the quartz substrate 30 is performed by moving the multi-axis stage 28 on which the quartz substrate 30 is placed. The multi-axis stage 28 is configured to move in any of the X direction, the Y direction, and the Z direction. The multi-axis stage 28 moves under the control of the computer device 10 via the driver 9. That is, the computer apparatus 10 drives the multi-axis stage 28 according to a predetermined program so that the laser beam condensing point is scanned on an arbitrary predetermined locus on the quartz substrate 30. Further, above the multi-axis stage 28, a CCD camera 21 for aligning the alignment of the quartz crystal substrate 30 placed on the multi-axis stage 28 is provided. Based on the image of the CCD camera 21. The irradiation position of the laser beam on the quartz substrate 30 is determined.

In the present embodiment, by moving the multi-axis stage 28 in, for example, one direction, the linearly altered portions 151 and 152 along the extending direction of the tuning fork arms 121 and 122 are formed on the quartz substrate 30. At this time, as described above, the movement speed of the multi-axis stage 28 is set to 2.5 mm per second, and the laser beam irradiation interval is set to 5 kHz, so that the interval between adjacent irradiation lines, that is, the so-called spot interval is set to 0.5 μm. Process to connect. Further, the focal length is changed by 5 μm in the thickness direction of the quartz substrate 30 having a thickness of 100 μm, and the altered portions 151 and 152 are formed in the entire thickness direction of the quartz substrate 30 as shown in FIG.
Although not shown, it is preferable to form a mask pattern corresponding to the laser irradiation region on the surface of the resonator element main body 102.

  Next, as shown in FIG. 5G, an Au film and a Cr film are formed on the entire surface of the quartz substrate 30 having the altered portions 151 and 152 to form the electrode film 33. Then, by etching the Cr film and the Au film in this order according to the pattern shape of the resist mask 34 formed on the electrode film 33, as shown in FIG. 5 (h), the excitation electrodes 123a and 124a, the drive electrodes 123b and 124b. Base electrodes 125a and 125a (FIG. 2) and electrode 125b (FIG. 2) are formed. Thereafter, by removing the resist mask 34, the tuning-fork type crystal vibrating piece 1 of the present embodiment having the altered portions 151 and 152 inside is obtained.

According to such a manufacturing method, it is possible to form the altered portions 151 and 152 only in a predetermined region of the tuning fork type crystal vibrating piece 1. Further, by using the femtosecond laser, it is possible to reliably and easily form the altered portions 151 and 152 in a necessary number and in a necessary number.
In each figure, the altered portions 151 and 152 are drawn continuously, but they may be a collection of laser irradiation spots (regular or random).
The tuning fork type crystal vibrating piece 1 may be made of a Z-cut crystal piece.

(Second Embodiment)
Next, the tuning fork type crystal vibrating piece 2 according to the second embodiment of the present invention will be described. 7 is a plan view showing a schematic configuration of the tuning-fork type crystal vibrating piece of the second embodiment, FIG. 8 is a cross-sectional view taken along the line FF ′ of FIG. 7, and FIG. 9 shows the vibrating piece main body of the second embodiment. It is a top view. In the following description, a structure different from the previous embodiment will be described in detail, and description of common parts will be omitted. Moreover, in each drawing used for description, the same code | symbol shall be attached | subjected to the same component as FIGS.

  As shown in FIG. 7, the tuning fork type crystal vibrating piece 2 according to the present embodiment has grooves 141 and 142 extending in the extending direction of the tuning fork arms 121 and 122 in a part of both main surfaces of the tuning fork arms 121 and 122. Yes. Since the grooves 141 and 142 are similarly formed on both main surfaces of the tuning fork arms 121 and 122, they are substantially H-shaped in the sectional view shown in FIG. The lengths of the grooves 141 and 142 are set to 50% to 70% with respect to the length L of the tuning fork arms 121 and 122.

Excitation electrodes 123a and 124a are formed in the grooves 141 and 142 formed in the tuning fork arms 121 and 122, as shown in FIGS.
Further, drive electrodes 123b and 124b are disposed on both side surfaces of the tuning fork arms 121 and 122, and base electrodes 125a and 125a are disposed on the base 110.

  In the tuning fork type crystal vibrating piece 2 of the present embodiment, altered parts 161 and 162 as shown in FIGS. 8 and 9 are formed on the tuning fork arms 121 and 122, respectively. The altered portions 161 and 162 are formed over the entire thickness direction of the resonator element. Therefore, the thickness of the region overlapping with the grooves 141 and 142 in plan view is thinner than that of the arm portion tip side. In the grooves 141 and 142, the altered portions 161 and 162 constitute the bottom walls of the grooves 141 and 142.

Next, an example of a method for manufacturing the tuning-fork type crystal vibrating piece 2 of the present embodiment will be described with reference to FIGS. The formation of the quartz substrate 30 in the outer shape of the tuning fork type quartz vibrating piece 2 is the same as in the previous embodiment.
In this embodiment, after finishing FIG. 4 (a)-(d) and FIG.5 (e), the resist mask 32 and the protective film 31 are peeled off from the quartz substrate 30, and as shown in FIG.10 (i). Put it in a state.
Next, as shown in FIG. 10J, a protective film 41 made of a Cr film and an Au film is formed on the entire surface of the quartz crystal substrate 30, and a patterned resist mask 42 is formed on the protective film 41. . This resist mask 42 corresponds to the groove pattern formed in each tuning fork arm 121, 122.

  Next, as shown in FIG. 10K, the protective film 41 is patterned by etching through the resist mask 42, and a part of the quartz substrate 30 is exposed. Thereafter, by performing an etching process on the quartz substrate 30 for a predetermined time, a plurality of grooves 141 and 142 are formed on the front and back surfaces of the tuning fork arms 121 and 122, respectively, as shown in FIG. In the present embodiment, the quartz substrate 30 is etched to form grooves 141 and 142 on both main surfaces of the tuning fork arms 121 and 122, respectively. Here, in the etching process, the processing time is adjusted so as to obtain a desired groove depth.

  Next, as shown in FIG. 11 (m), a femtosecond laser is irradiated in a line shape from the tip of the tuning fork arms 121, 122 to the end of the base 110 by the laser irradiation device 20, and the altered portion is formed in the entire thickness direction of the substrate. 161, 162 are formed.

  Next, as shown in FIG. 11 (n), an electrode film 33 is formed by forming an Au film and a Cr film on the entire surface of the quartz substrate 30 having the altered portions 161 and 162. Then, as shown in FIG. 11 (o), the excitation film as shown in FIG. 11 (p) is obtained by etching the Cr film and the Au film in this order in accordance with the pattern shape of the resist mask 34 formed on the electrode film 33. 123a and 124a, drive electrodes 123b and 124b, base electrodes 125a and 125a (FIG. 2), and electrode 125b (FIG. 2) are formed. Then, the resist mask 34 is peeled off to obtain the tuning fork type crystal vibrating piece 2 of the present embodiment having the altered portions 161 and 162 inside.

  The tuning-fork type crystal vibrating piece 2 of the present embodiment manufactured in this way has the altered portions 161, over the extending directions of the grooves 141, 142 and the tuning-fork arms 121, 122 including the bottoms of the grooves 141, 142. 162. These altered portions 161 and 162 can prevent the Q value from decreasing, and the grooves 141 and 142 can improve vibration efficiency and suppress power loss. Therefore, by these synergistic effects, a more stable frequency characteristic can be obtained even when the entire resonator element is downsized, and the reliability is excellent.

  In each of the embodiments described above, the altered portions 151, 152, 161, 162 are formed in the entire length direction of the tuning fork type crystal vibrating pieces 1, 2, that is, from the tuning fork arms 121, 122 to the base 110. The altered portion may be provided only in the tuning fork arms 121 and 122. In this case, the altered portion extends at least over the entire length direction of the tuning fork arms 121 and 122.

Example 1
Next, the difference in performance between the tuning fork type quartz vibrating piece having the altered portion according to the present invention and the conventional tuning fork type quartz vibrating piece having no altered portion was examined. Each resonator element is a grooved tuning-fork type crystal resonator element having a tuning fork arm 121, 122 having a width W1 of 50 μm, an arm length L of 1100 μm, and an oscillation frequency of 32 kHz. Is formed over the length of the tuning fork arm, the Q value of the tuning fork type quartz vibrating piece having no altered portion is 15000, whereas the Q value of the tuning fork type quartz vibrating piece having the altered portion is Greatly improved to about 24,000. This confirmed that the altered portion contributed to the improvement of the Q value.
In addition, since the Q value when the altered portion is formed in a part of the tuning fork arm in the length direction is 21000, the Q value can be improved by providing the altered portion over the length of the tuning fork arm. Was found to improve. Therefore, it is considered that a higher Q value can be obtained by providing the altered portion over the length of the resonator element.

(Vibrator)
FIG. 12 is a diagram showing a ceramic package tuning fork type vibrator 200 which is a vibrator according to the present invention. This ceramic package tuning fork type resonator 200 uses the vibrating piece of the first or second embodiment described above as the tuning fork type quartz vibrating piece 100. Accordingly, the same reference numerals are used for the configuration, operation, and the like of the tuning fork type crystal vibrating pieces 1 and 2 and the description thereof is omitted.

  As shown in FIG. 12, the ceramic package tuning fork vibrator 200 has a box-shaped package 210 having a space inside. The package 210 has a base portion 211 at the bottom thereof. The base portion 211 is formed of ceramics such as alumina, for example.

  A sealing portion 212 is provided on the base portion 211, and the sealing portion 212 is formed from the same material as the base portion 211. A lid 213 is placed on the upper end of the sealing portion 212, and the base portion 211, the sealing portion 212, and the lid 213 form a hollow box. A package-side electrode 214 is provided on the base portion 211 of the package 210 thus formed.

  The base 110 of the tuning fork type crystal vibrating piece 1 is fixed on the package side electrode 214 via a conductive adhesive or the like. Since the tuning-fork type quartz vibrating piece 100 has the configuration of either the first or second embodiment as described above, the tuning-fork type quartz vibrating piece 100 is small and has stable frequency characteristics. The child 200 is also a small and high-performance vibrator with stable frequency characteristics.

  FIG. 13 is a diagram showing a tuning fork crystal oscillator 400 which is an oscillator according to the present invention. Since the tuning fork crystal oscillator 400 has the same configuration in many parts as the ceramic package tuning fork resonator 200 described above, the same configuration and operation as the ceramic package tuning fork resonator 200 are the same. The description will be omitted using reference numerals.

  A tuning fork crystal oscillator 400 shown in FIG. 13 has an integrated circuit 410 arranged as shown in FIG. 13 below the tuning fork type crystal vibrating piece 1 in the ceramic package tuning fork type resonator 200 shown in FIG. It is a thing. That is, in the tuning fork crystal oscillator 400, when the tuning fork type crystal vibrating piece 100 disposed therein vibrates, the vibration is input to the integrated circuit 410, and then functions as an oscillator by extracting a predetermined frequency signal. It will be. That is, since the tuning fork type crystal vibrating piece 100 accommodated in the tuning fork crystal oscillator 400 has either the first or second configuration, the tuning fork type crystal vibrating piece 100 is small and has a stable oscillation frequency. The digital tuning fork crystal oscillator 400 is also a small and high-performance oscillator with a stable oscillation frequency.

  FIG. 14 is a view showing a cylinder type tuning fork vibrator 500 which is a vibrator according to the present invention. This cylinder-type tuning fork vibrator 500 uses the tuning-fork type crystal vibrating pieces 1 and 2 of the first embodiment or the second embodiment described above. Therefore, the configuration, operation, and the like of the tuning fork type crystal vibrating piece 100 are omitted by using the same reference numerals. FIG. 14 is a schematic diagram showing the configuration of a cylinder type tuning fork vibrator 500. As shown in FIG. 14, the cylinder type tuning fork vibrator 500 has a metal cap 530 for accommodating the tuning fork type crystal vibrating piece 1 therein. The cap 530 is press-fitted into the stem 520 so that the inside thereof is maintained in a vacuum state.

  In addition, two leads 510 for holding the substantially H-shaped tuning-fork type crystal vibrating piece 1 housed in the cap 530 are disposed. When a current or the like is applied to the cylinder type tuning fork vibrator 500 from the outside, the tuning fork arms 121 and 122 of the tuning fork type crystal vibrating piece 100 vibrate and function as a vibrator. At this time, the tuning-fork type crystal vibrating piece 100 has either the configuration of the first or second embodiment, and is compact and has a stable oscillation frequency. Therefore, the cylinder-type tuning fork vibrator 500 on which the vibrating piece is mounted. Is a small, high-performance vibrator with a stable oscillation frequency.

  The preferred embodiments according to the present invention have been described above with reference to the accompanying drawings. However, it goes without saying that the present invention is not limited to such examples, and the above embodiments may be combined. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

  For example, the tuning fork type crystal vibrating pieces 1 and 2 according to the previous embodiment are not limited to the above-described example, but other electronic devices, portable information terminals, televisions, video devices, so-called radio cassettes, personal computers, and other watches. It can also be used for internal devices and watches.

DESCRIPTION OF SYMBOLS 1, 2 ... Tuning fork type crystal vibrating piece (crystal vibrating piece), 121, 122 ... Tuning fork arm (vibrating arm part), 110 ... Base, 123a, 124a ... Excitation electrode, 123b, 124b ... Driving electrode, 125a, 125a ... Base Electrode, 125b ... Electrode, 151, 152, 161, 162 ... Altered part, 141, 142 ... Groove, 200 ... Ceramic package tuning fork vibrator, 400 ... Tuning fork crystal oscillator (oscillator), 500 ... Cylinder type tuning fork vibrator (vibration) Child)

Claims (15)

A vibrating piece body having a base and a pair of vibrating arms extending in parallel from the base, excitation electrodes formed on both main surfaces of the vibrating arms, and formed on both sides of the vibrating arms A quartz crystal resonator element having a driven electrode,
A quartz crystal vibrating piece, wherein an altered portion extending along the vibrating arm portion and having a tissue structure different from that of a quartz crystal is formed at least over the entire length direction of the vibrating arm portion. 2. The quartz crystal vibrating piece according to claim 1, wherein the altered portion is formed from a tip end of the vibrating arm portion to an end portion of the base portion. 3. The quartz crystal resonator element according to claim 1, wherein the altered portion is in a state where at least amorphous, polycrystalline, quartz, cavities, and the like are mixed. The said altered part is located in the width direction center of the said vibration arm part, and the single crystal part exists in the width direction both sides of the said altered part, The Claim 1 thru | or 3 characterized by the above-mentioned. Crystal vibrating piece. 5. The quartz crystal resonator element according to claim 1, wherein the altered portion is formed so as to penetrate the vibrating arm portion in a thickness direction. 6. 6. The quartz crystal resonator element according to claim 1, wherein a width of the altered portion is in a range of 10% to 80% with respect to a width of the vibrating arm portion. The quartz crystal resonator element according to any one of claims 1 to 6, wherein grooves extending along a length direction of the vibrating arm portion are respectively formed on both main surfaces of the vibrating arm portion. . A vibrating piece body having a base and a pair of vibrating arms extending in parallel from the base, excitation electrodes formed on both main surfaces of the vibrating arms, and formed on both sides of the vibrating arms A method for producing a quartz crystal resonator element having a drive electrode,
Forming the base and the vibrating arm by etching a quartz substrate;
Irradiating a laser along the vibrating arm, and forming an altered portion of a tissue structure different from quartz over at least the entire length of the vibrating arm; and
And a step of forming the excitation electrode and the drive electrode. 9. The method for manufacturing a quartz crystal vibrating piece according to claim 8, wherein the altered portion is formed by continuously irradiating the laser from a tip of the vibrating arm portion to an end portion of the base portion. The method for manufacturing a quartz crystal vibrating piece according to claim 8 or 9, wherein the laser is a femtosecond pulse laser. 11. The method for manufacturing a quartz crystal vibrating piece according to claim 8, wherein an output of the laser is 300 nJ or more and less than 500 nJ. Before the step of forming the altered portion,
12. The method for manufacturing a quartz crystal vibrating piece according to claim 8, further comprising a step of forming grooves on both main surfaces of the vibrating arm portion.   A vibrator comprising the crystal vibrating piece according to claim 1 housed in a package.   8. An oscillator comprising the crystal resonator element according to claim 1 and an integrated circuit housed in a package.   8. An electronic apparatus comprising: the crystal resonator element according to claim 1; and a vibrator having the vibrator housed in a package, wherein the vibrator is connected to a control unit.

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