JP2006311444A - Piezoelectric vibration chip, its manufacturing method, and piezoelectric device utilizing the piezoelectric vibration chip element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric vibration chip which is excellent in mass productivity and the frequency of which is adjusted highly precisely, and to provide a its manufacturing method and a piezoelectric device utilizing the piezoelectric vibration chip. <P>SOLUTION: The piezoelectric vibration chip is provided with weights 62 located at regions ER1, ER2, ER3, ER4 to which laser beams are respectively emitted for frequency adjustment, each of the weights 62 includes a region for roughly adjusting the frequency and a region for fine-adjusting the frequency relatively, and the region for roughly adjusting the frequency is formed to have a greater mass than that of the region for fine-adjusting the frequency relatively. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a piezoelectric vibrating piece having a weight for adjusting a frequency by laser light, a piezoelectric device using the piezoelectric vibrating piece, and a method for manufacturing the piezoelectric device.

FIG. 12 is a schematic plan view of the vicinity of the tip of the conventional vibrating arm 1 (see, for example, Patent Document 1).
The vibrating arm 1 in this figure is a single vibrating arm for a tuning-fork type piezoelectric vibrating piece having a plurality of vibrating arms extending from the base, and a weight 2 for frequency adjustment is provided near the tip. Yes. That is, by irradiating the weight 2 with laser light, the mass near the tip of the vibrating arm is reduced, and the frequency of the piezoelectric vibrating piece is adjusted.

Specifically, the vibrating arm 1 has been devised as follows in order to efficiently perform frequency adjustment with a small amount of laser light irradiation and enable fine frequency adjustment.
That is, the vibrating arm 1 irradiates a laser beam on the distal end side (the right side in FIG. 12) with a high mass reduction effect to adjust the frequency roughly, and the base side from the coarse adjustment region E1. A fine adjustment region E2 for finely adjusting the frequency by irradiating laser light (on the left side of FIG. 12). The laser light applied to the coarse adjustment region E1 has a relatively large spot diameter d1 to enable efficient frequency adjustment. The laser light applied to the fine adjustment region E2 The diameter d2 is made smaller than d1, the resolution is increased, and finer frequency adjustment is possible. Further, in this figure, the laser beam is irradiated so that the spot diameter d3 is smaller than the spot diameter d2, and the resolution is further increased.

Japanese Patent Laid-Open No. 2003-133879

  However, the frequency adjustment that changes the resolution by changing the spot diameter of the laser beam in this way requires a laser apparatus having different spot diameters, and thus requires a plurality of apparatuses or an expensive apparatus. There are problems such as.

  An object of the present invention is to provide a piezoelectric vibrating piece whose frequency is adjusted with high accuracy at low cost, a method for manufacturing the same, and a piezoelectric device using the piezoelectric vibrating piece.

  According to the first aspect of the present invention, there is provided a piezoelectric vibrating piece provided with a weight irradiated with a laser beam for frequency adjustment, wherein the weight is relatively coarsely adjusted in frequency. And an area for finely adjusting the frequency, and the area for coarsely adjusting the frequency is relatively smaller than the area for finely adjusting the frequency. This is achieved by the piezoelectric vibrating piece formed so as to increase the mass.

According to the configuration of the first invention, the weight provided in the region irradiated with the laser light for frequency adjustment is relatively finely adjusted in the region for adjusting the frequency relatively coarsely. Compared with the area | region for doing, it is formed so that mass may become large. For this reason, even if the spot diameter of the laser beam applied to the region for adjusting the frequency coarsely and the region for adjusting the frequency finely are the same, the mass of the weight reduced by the laser beam irradiation is The area for coarse adjustment is larger than the area for fine adjustment. Therefore, even if a laser device having a different spot diameter is not used, in the region for coarsely adjusting the frequency, an effective frequency adjustment with a large mass reduction effect is possible and the region for finely adjusting the region. , The mass reduction effect is small and fine frequency adjustment is possible.
Thus, it is possible to provide a piezoelectric vibrating piece with a highly accurate frequency adjustment at low cost.

According to a second aspect, in the configuration of the first aspect, the thickness of the weight is relatively changed between the region for coarsely adjusting the frequency and the region for finely adjusting the frequency. Thus, the masses are different.
According to the configuration of the second aspect of the invention, the region for adjusting the frequency roughly and the region for finely adjusting the frequency appear to have different masses by relatively changing the thickness of the weight. Therefore, the same effect as the first invention is exhibited.

According to a third aspect of the present invention, in the configuration of the first or second aspect of the invention, the area for adjusting the frequency roughly and the area for finely adjusting the frequency are relative to each other in the type of the weight. It is characterized in that the mass is different by being changed to.
According to the configuration of the third aspect of the invention, the region for adjusting the frequency coarsely and the region for finely adjusting the frequency appear to have different masses by relatively changing the type of weight. Therefore, the same effect as the first invention is exhibited. Furthermore, for example, even if the thickness of the weight is not changed, the same effect as that of the first invention can be exhibited. Therefore, the thickness of the vibrating arm including the weight can be reduced.

  According to a fourth aspect of the present invention, there is provided a piezoelectric device comprising: a package whose internal space is sealed by a lid; and a piezoelectric vibrating piece housed in the internal space of the package. The lid of the package is formed of a material that can transmit laser light, and the piezoelectric vibrating piece is provided with a weight that is irradiated with the laser light so as to transmit the cover. The weight has a region for adjusting the frequency roughly and a region for finely adjusting the frequency, and the region for adjusting the frequency roughly This is achieved by a piezoelectric device formed so as to have a relatively large mass compared to the region for finely adjusting the frequency.

  According to the configuration of the fourth aspect of the invention, the piezoelectric vibrating piece has the weight that is irradiated with the laser light so as to pass through the lid of the package, and this weight has a relatively rough frequency. The region for adjusting the frequency is formed so that the mass is larger than the region for finely adjusting the frequency. Therefore, the same effect as the first invention is exhibited. Furthermore, since the frequency can be adjusted by the laser beam transmitted through the transparent lid, the frequency can be adjusted immediately before completion, and a more accurate frequency can be obtained.

  According to the fifth aspect of the present invention, the outer shape forming step for forming the outer shape from the piezoelectric material, and the region where the laser beam for frequency adjustment is irradiated after and / or before the outer shape step. And a weighting step of attaching a weight to the piezoelectric vibrating piece, wherein the region for adjusting the frequency relatively coarsely adjusts the frequency finely in the weighting step. This is achieved by a method of manufacturing a piezoelectric vibrating piece to which the weight is attached so as to increase the mass compared to the region for.

  According to the configuration of the fifth aspect of the invention, in the weighting step, the mass for adjusting the frequency coarsely is relatively larger than the region for finely adjusting the frequency. And attach a weight. Therefore, without changing the spot diameter of the laser beam for each region irradiated with the laser beam, it is possible to adjust the frequency with a large mass reduction effect and an efficient frequency, and the fine frequency adjustment with a small mass reduction effect is possible. To do. Therefore, it is not necessary to use a laser device having a different spot diameter, and the same effect as the first invention is exhibited.

1 to 4 show a piezoelectric device 30 according to a first embodiment of the present invention, in which FIG. 1 is a schematic plan view of the piezoelectric device 30, and FIG. 2 is a schematic sectional view taken along line AA in FIG. 3 is a schematic perspective view of a piezoelectric vibrating piece used in the piezoelectric device 30, and FIG. 4 is a schematic cut end view taken along line BB of FIG.
The piezoelectric device means all products in which a piezoelectric vibrating piece is contained in a package including a cylinder or the like, regardless of the name of a piezoelectric vibrator, a piezoelectric oscillator, or the like.
3 are shown for the convenience of understanding, and do not represent a cross section or the like.

In the piezoelectric device 30 shown in these drawings, an example in which a piezoelectric vibrator is configured when the frequency required as a finished product is 32 KHz is shown, and the piezoelectric vibrating piece 20 is accommodated in the package 37.
As shown in FIG. 2, the package 37 of the present embodiment is formed by stacking, for example, first to third substrates 37a, 37b, and 37c formed by molding an aluminum oxide ceramic green sheet as an insulating material. Then, it is formed by sintering.

The first substrate 37a is formed with a predetermined hole on the inner side thereof so that a predetermined inner space S is formed on the inner side of the package 37 when the first substrate 37a is stacked on the second substrate 37b. The internal space S becomes a cavity for accommodating the piezoelectric vibrating piece 20.
Further, a brazing material 38 such as low-melting glass is applied to the opening end surface of the first substrate 37a on the side opened to the upper side in FIG. The lid is sealed. The lid 39 is a material that transmits light so that the frequency can be adjusted by a mass reduction method by applying laser light to the weight provided on the piezoelectric vibrating piece 20 even after the lid is sealed, for example, It is formed from glass. This weight will be described later in detail.

On the surface exposed to the internal space S of the second substrate 37b, for example, mount electrodes 31 and 32 formed by nickel plating and gold plating on a tungsten metallization are provided.
The mount electrodes 31 and 32 are routed through the package and connected to the mounting terminal portions 41 and 42, thereby having different polarities, and serve as electrodes for supplying a driving voltage to the piezoelectric vibrating piece 20.
Then, a conductive adhesive such as silicone, epoxy, or polyimide is applied to the upper surfaces of the mount electrodes 31 and 32 as the adhesives 43 and 43, and the piezoelectric vibrating piece 20 is applied on the adhesives 43 and 43. Is mounted and the adhesives 43 and 43 are cured, so that the mount electrodes 31 and 32 and the piezoelectric vibrating piece 20 are connected.

  In addition, an opening 45 is provided near the center of the bottom surface of the package 37 by forming through holes 45a and 45b continuous with the second substrate 37b and the third substrate 37c. The opening 45 is a hole for preventing harmful gas from adhering to the piezoelectric vibrating piece 20. That is, it is a hole for evacuating the gas generated from the conductive adhesive 43, the brazing material 38, etc. by heating (annealing) the inside of the package 37, for example. The opening 45 has a larger inner diameter than the through hole 45a that opens to the inside of the package, so that the opening 45 has the package 37 turned upside down. In this case, an upward stepped portion 48 is formed.

  Then, the inner surface of the opening 45 is coated with nickel plating and gold plating as a base, and after exhausting harmful gas, as shown in FIG. It is designed to be sealed. In the present embodiment, for example, an alloy of gold (Au) and tin (Sn) is used for the sealing material 46.

The piezoelectric vibrating piece 20 is made of, for example, quartz or the like, and other piezoelectric materials such as lithium tantalate and lithium niobate can be used.
In the case of the present embodiment, the piezoelectric vibrating piece 20 is formed in a small size, and in order to obtain the required performance, a pair of vibrating arms 35 extending in parallel from the base 51 toward the right in FIG. 36.

  The base 51 is a part for supporting the pair of vibrating arms 35 and 36. The base 51 of this embodiment is also a part for joining the piezoelectric vibrating piece 20 to the mount electrodes 31 and 32. As shown in FIGS. 1 and 3, the extraction electrodes 33a, 34a is formed, and the extraction electrodes 33a and 34a and the mount electrodes 31 and 32 are electrically and mechanically connected.

  As shown in FIG. 3, the vibrating arms 35 and 36 are formed with long grooves 52 and 53 extending in the longitudinal direction on the front and back surfaces, respectively, and the longitudinal section in the width direction is substantially H-shaped. Excitation electrodes 33 and 34 are formed in the long grooves 52 and 53, and the excitation electrode 34 is formed on the side surface of the vibrating arm 35 so as to face the excitation electrode 33 in the long groove 52. An excitation electrode 33 is formed on the side surface of the vibrating arm 36 so as to face the excitation electrode 34.

  That is, the excitation electrode 33 in the long groove 52 of the vibrating arm 35 is formed from the inner side surface of the vibrating arm 36 through the tip region to the outer side surface, and is electrically connected to the extraction electrode 34 a of the base 51. In addition, the excitation electrode 34 in the long groove 53 of the vibrating arm 36 is formed from the outer side surface of the vibrating arm 35 to the inner side surface through the distal end region through the extraction electrode 33 a of the base 51. In this way, the excitation electrodes in the long grooves 52 and 53 and the excitation electrodes on the side surfaces opposite to the excitation electrodes are arranged to have different polarities, and the electric field efficiency in each arm is increased, so that the vibration arms 35 and 36 are small. Is possible. For the excitation electrodes 33 and 34, for example, a structure in which a gold plating is coated on a base layer made of chrome plating is suitable.

  Here, as shown in FIG. 3, the excitation electrodes 33 b and 34 b in the tip region of the vibrating arms 35 and 36 formed so as to extend the exciting electrodes 33 and 34 in the long grooves 52 and 53 are the vibrating arms 35 and 36. 3 is also formed on the main surface (the surface opposite to the lid in FIG. 3), specifically, the longer it is in the longitudinal direction, the closer to the long grooves 52, 53 from the tip of each arm. Has been. Excitation electrodes 33b and 34b formed on the front and back surfaces of the tip regions of the vibrating arms 35 and 36 are not only provided for generating electrolysis in each arm of the piezoelectric vibrating piece 20, but also for adjusting the frequency. It has the role of a weight. That is, as will be described later, it is a weight for adjusting the frequency by being irradiated with laser light and reducing the mass.

Hereinafter, the weight for adjusting the frequency will be described in detail. However, the configurations of the weights provided on the vibrating arm 35 and the vibrating arm 36 are substantially the same, and thus the description of the vibrating arm 36 is omitted.
As shown in FIG. 4, another weight is provided on the excitation electrode 34b that is a weight, and a weight 62 that is irradiated with laser light for frequency adjustment is formed as a whole.
The weight 62 has a region for adjusting the frequency roughly and a region for finely adjusting the frequency. The region for adjusting the frequency roughly As compared with the region for finely adjusting the frequency, the mass is relatively increased.

That is, in the case of the present embodiment, the weight 62 sequentially improves the resolution of frequency adjustment from the distal end side of the vibrating arm 35 toward the base side (long groove 52 side), and the laser light of the vibrating arm 35 is irradiated. A frequency adjustment region is formed so that the tip region is divided according to resolution.
Specifically, the tip region of the vibrating arm 35 is divided into four sections, and the laser beams LB1, LB2, LB3, and LB4 are irradiated according to the sections. The weight 62 has the largest mass in the adjustment region ER1 on the most distal end side of the vibrating arm 35, and then the coarse adjustment region ER2 and the coarse adjustment region ER2 for finer frequency adjustment than the earliest adjustment region ER1. In addition, the mass decreases in the order of the fine adjustment region ER3 for finely adjusting the frequency. Finally, as described later in the manufacturing method, the opening 45 is sealed with a sealing material 46 (see FIG. 2). It is formed so that the mass of the under-sealing adjustment region ER4 for finer frequency adjustment than the region ER3 is the smallest.

Furthermore, in the present embodiment, the region for adjusting the frequency coarsely and the region for finely adjusting the frequency have different masses because the thickness of the weight 62 is relatively changed. In FIG. 4, the weights 62 that are reduced by one-time laser light irradiation are gradually multilayered toward the tip.
Specifically, as shown in FIG. 4, an excitation electrode 34 b as a weight is provided on the entire surface of the vibrating arm 35 (upper surface in FIG. 4). Further, with respect to the tip region of the back surface (the lower surface in FIG. 4) of the vibrating arm 35, the sealed adjustment region ER4 is not provided with a weight, and the fine adjustment region ER3 has a single layer structure in which an excitation electrode 34b as a weight is attached. The coarse adjustment region ER2 has a two-layer structure in which a weight 56 made of Au (gold) or the like is attached to the excitation electrode 34b. The earliest adjustment region ER1 has a weight 56 and Au ( It has a three-layer structure with a weight 58 made of gold or the like attached thereto. In addition, the hole opened in the weight 62 of FIG. 4 is a trace irradiated with the laser beams LB1, LB2, LB3, and LB4.

Next, a method for manufacturing the piezoelectric device 30 will be described.
FIGS. 5 to 9 are diagrams for explaining a method of manufacturing the piezoelectric device 30. FIG. 5 is a process diagram of the piezoelectric device 30, and FIGS. 6 to 8 are conceptual diagrams of manufacturing processes corresponding to the process of FIG. FIG. 9A shows a trace of laser beam irradiation on the surface of the vibrating arm, and FIG. 9B shows a trace of laser beam irradiation on the back surface of the vibration arm.
Note that the vibrating arm 35, the weight provided on the vibrating arm 35, the processing method for the weight, and the like are the same for the vibrating arm 36, and therefore the description thereof will be omitted.

In the piezoelectric device manufacturing method in these drawings, a plurality of the tuning fork type piezoelectric vibrating reeds already described are formed on the wafer by, for example, wet etching (outer forming step).
Then, the extraction electrode and the excitation electrode (the tip area of the vibrating arm becomes a weight) that has already been described are deposited on these piezoelectric vibrating pieces by sputtering or the like, and then the frequency adjustment is performed in a plurality of subsequent steps. Weighting is performed (ST1: weighting step).
Specifically, as shown in FIG. 6A, the excitation electrode 34b as a weight is vapor-deposited by sputtering or the like on the entire tip region on the surface side (upper side in the figure) of the vibrating arm 35. Further, on the back surface side (lower side in the figure) of each vibrating arm 35, the excitation electrode 34b as a weight is deposited by sputtering or the like on the fine adjustment region ER3, the coarse adjustment region ER2, and the first adjustment region ER1. .
For the rough adjustment region ER2 on the back surface side and the first adjustment region ER1, a weight 56 made of Au (gold) or the like is vapor-deposited on the excitation electrode 34b as a weight by sputtering or the like, and then the back surface side. In the first adjustment region ER1, a weight 58 made of Au (gold) or the like is further deposited on the weight 56 by sputtering or the like.

  Next, as shown in FIG. 6B, the laser beam LB1 is applied to the weights 34b, 34b, 56, 58 provided in the earliest adjustment region ER1 of each of the vibrating arms 35, 36 of the plurality of piezoelectric vibrating pieces. Before the piezoelectric vibrating piece is irradiated and bonded to the package, the frequency is roughly adjusted (ST2 in FIG. 5: frequency adjustment on the wafer). Specifically, as shown in FIG. 9, the most distal weight 62 provided on the front and back surfaces of the vibrating arm 35 is irradiated a plurality of times using, for example, the YAG laser LB1, and the frequency required as a finished product. Is adjusted so that the variation in frequency when the frequency is 32 KHz is about 500 ppm. As described above, although the adjustment is rough, before the piezoelectric vibrating piece is bonded to the package, the laser beam is irradiated in advance to prevent adverse effects caused by the evaporated weight adhering to the package. be able to.

Next, a plurality of piezoelectric vibrating pieces are cut into individual pieces from the wafer, and each is joined to a package 37 in which the mount electrodes 31 and 32, the opening 45, etc. shown in FIGS. 5 ST3: mounting step).
As shown in FIG. 2, a brazing material 38 such as low melting glass is applied to the opening end surface of the package 37, and a lid 39 made of glass or the like that can transmit laser light is joined (ST4 in FIG. 5). Lid sealing step). In the present embodiment, after the lid sealing process is finished, the frequency variation of the piezoelectric vibrating piece has deteriorated to about 1500 ppm. As described above, although the frequency is adjusted in ST2, the frequency varies because the environment is changed in the mounting process (ST2) and the lid sealing process (ST3).

Next, as shown in FIG. 7 (c), the laser beams LB2 and LB3 are transmitted through the glass lid 39 and irradiated onto a weight (not shown) provided on the vibrating arm 35, thereby requesting a finished product. Adjustment is performed so as to substantially match the frequency to be applied (ST5 in FIG. 5: adjustment step before sealing).
In this embodiment, as shown in FIG. 7C, this pre-sealing adjustment step irradiates laser light LB2 on the tip side of a weight (not shown) provided on the vibrating arm 35 to roughen the frequency. The coarse adjustment step (ST5-1 in FIG. 5) for adjustment is performed, and then the frequency is adjusted by irradiating the weight (not shown) provided on the base 51 side with respect to the coarse adjustment step with the laser beam LB3. The fine tuning process (ST5-2 in FIG. 4) is performed.

  Specifically, in the coarse adjustment step (ST5-1 in FIG. 5), as shown in FIGS. 4 and 9, the mass reduction effect is on the base side (base side) smaller than the earliest adjustment region ER1. The weights 34b, 34b, 56 provided in the coarse adjustment region ER2 of the vibrating arm 35 are irradiated with the laser beam LB2 a plurality of times using, for example, a YAG laser. Then, although slightly rough, the frequency adjustment is finer than the wafer-like frequency adjustment (ST2 in FIG. 5), and the frequency variation is adjusted to about 200 to 300 ppm.

Further, in the fine adjustment step (ST5-2 in FIG. 5), as shown in FIGS. 4 and 9, the mass reduction effect is smaller on the base side (base side) than in the coarse adjustment step (ST5-1 in FIG. 5). Thus, the weights 34b and 34b provided in the fine adjustment region ER3 of the vibrating arm 35 are irradiated with the laser beam LB3 a plurality of times using, for example, a YAG laser.
And about the piezoelectric vibrating piece after passing through this fine adjustment process (ST5-2 of FIG. 5), it adjusts so that the variation in the frequency may be set to about 10 ppm. This variation of about 10 ppm is so small that most products can pass in the inspection process unless there is another reason.

  In the pre-sealing adjustment step (ST5 in FIG. 5), the laser beams LB2 and LB3 are irradiated a plurality of times, but the laser beams LB2 and LB3 have a temperature near the focal point of 1000 ° C. or higher. As shown in FIG. 7D, thermal stress is applied to the vibrating arm 35 by this heating, and the residual stress 60 exists in the vibrating arm 35.

  Next, gas is extracted from an opening 45 (see FIG. 2) provided in the package. That is, the gas generated from the adhesive or the like in the mounting step (ST3) or the lid sealing step (ST4) is evacuated from the opening. Then, in a state where the inside space S is in a vacuum atmosphere, as shown in FIG. 7E, the sealing material 46 is placed on the upward stepped portion 48 of the opening 45 of the piezoelectric device turned upside down and heated. Then, the sealing material 46 is wet-spread on a metal cover (not shown) provided only on the inner surface of the opening 45 to seal the package (ST6 in FIG. 5: hole sealing step).

  Here, in this hole sealing step (ST6), not only the sealing material 46 is heated, but also the piezoelectric vibrating piece 20 is heated. In this embodiment, before the gas is evacuated from the opening 45, the entire piezoelectric device is heated so that the gas remaining in the conductive adhesive 43 and the brazing material 38 can be completely extracted. In addition, the piezoelectric vibrating piece 20 is heated. Specifically, in a furnace having a temperature of about 205 ° C. to 300 ° C. so that the residual stress 60 of the vibrating arm 35 generated in the pre-sealing adjustment step (ST5 in FIG. 5) can be substantially eliminated rather than relaxed. The entire piezoelectric device before completion is placed for about 30 minutes to 1 hour and heated at a relatively low temperature for a relatively long time. Then, after the piezoelectric vibrating piece 20 is heated and the gas is extracted from the opening 45 in this way, the mounted sealing material 46 is irradiated with, for example, laser light, or a pin connected to the heating means is contacted. The package 37 is sealed by heating and melting.

  When the hole sealing step (ST6) is performed in this way, the frequency of the piezoelectric vibrating piece is slightly smaller than that of the piezoelectric vibrating piece immediately after the fine adjustment step (ST5-2 in FIG. 5), but 30 The frequency starts to vary again to about 50 ppm. This variation is considered to be a characteristic change of the vibrating piece due to the disappearance of the residual stress generated in the pre-sealing adjustment step (ST5 in FIG. 5) by heating the piezoelectric vibrating piece.

Therefore, as shown in FIGS. 4, 8, and 9, the slight frequency fluctuation generated in the hole sealing step (ST6) is more effective than the fine adjustment step (ST5-2 in FIG. 5). The surface weight 34b on the small base side (base side) provided in the sealing under adjustment region ER4 of the vibrating arm 35 is irradiated with the laser beam LB4 a plurality of times using, for example, a YAG laser, and is required as a finished product. The frequency is adjusted so as to match the frequency to be adjusted (ST7 in FIG. 5: adjustment step under sealing), and the frequency variation of the piezoelectric device is adjusted to about 10 ppm.
The frequency and other inspections of the piezoelectric device are then completed.

The first embodiment of the present invention is configured as described above, and the frequency adjusting weight 62 has a relatively coarse frequency adjustment region for finely adjusting the frequency. It is formed to have a larger mass than the region. For this reason, even if the spot diameter of the laser beam irradiated to the region for adjusting the frequency coarsely and the region for fine adjustment are substantially the same, the mass of the weight reduced by the laser beam irradiation is The region for coarse adjustment is larger than the region for fine adjustment. Therefore, even if a laser device having a different spot diameter is not used, in the region for coarsely adjusting the frequency, an effective frequency adjustment with a large mass reduction effect is possible and the region for finely adjusting the region. , The mass reduction effect is small and fine frequency adjustment is possible.
In order to exhibit this effect of the present invention, it is not always necessary to carry out the manufacturing process shown in FIG. 5. For this reason, for example, as shown in FIG. The frequency may be adjusted by irradiating the laser beams LB1, LB2, and LB3 in accordance with the frequency adjustment region in which the resolution is divided into three sections.

  Further, by increasing the mass of the weight 62 provided on the vibrating arms 35 and 36, the mass reduction effect when the laser beam is irradiated is improved, and the spot diameter of the laser beam can be reduced. Even if the frequency adjustment region which is the tip region of 36 is reduced, this can be dealt with. For example, in the case of this embodiment, even when the distance from the tip of the long groove 52 to the tip of the vibrating arm is shortened, the earliest adjustment region ER1, coarse adjustment region ER2, fine adjustment region ER3, under-sealing adjustment Frequency adjustment divided into 4 sections of area ER4 became possible.

In addition, in the present embodiment, before the hole sealing step (ST6 in FIG. 5), a pre-sealing adjustment step for adjusting so as to substantially match the frequency required for the finished product is already performed (FIG. 5). ST5). Therefore, in the final adjustment process under sealing (ST7 in FIG. 5), the hole sealing process (ST6 in FIG. 5) between the adjustment process under sealing and the adjustment process before sealing is changed. It is only necessary to adjust the frequency.
In the pre-sealing adjustment step (ST5 in FIG. 5), since the laser beams LB2 and LB3 are irradiated, the thermal stress remains in the piezoelectric vibrating piece, but the subsequent hole sealing step (FIG. 5). In ST6), the vibrating arm is heated and this residual stress is eliminated in this embodiment.
Therefore, in the undersealing adjustment process (ST7 in FIG. 5), only the frequency changed by performing the hole sealing process (ST6 in FIG. 5) needs to be adjusted slightly, and further, the pre-sealing adjustment process (FIG. 5). Since the residual stress in ST5) disappears, only a small amount of thermal stress remains in the completed piezoelectric vibrating piece 20. Therefore, even when the completed piezoelectric device 30 is heated in a reflow furnace or the like when the substrate is mounted on the substrate, changes in the characteristics of the piezoelectric device can be suppressed.

FIG. 11 is a schematic longitudinal sectional view of the vibrating arm 35 for the piezoelectric device according to the second embodiment of the present invention, and corresponds to the sectional view of FIG.
In this figure, since the location which attached | subjected the code | symbol same as the code | symbol used in description of the piezoelectric device 30 mentioned above and its manufacturing method is a common structure, the overlapping description is abbreviate | omitted and it demonstrates centering on difference below. To do. In FIG. 11, the configuration of the vibrating arm 35 and the vibrating arm 36 is substantially the same, so only the vibrating arm 35 will be described below.

This vibrating arm 35 is mainly different from the first embodiment in that some types of weights 62 are different.
That is, the area for adjusting the frequency coarsely and the area for finely adjusting the frequency have different masses due to the relative change of the type of the weight 62.
Specifically, an excitation electrode 34 b as a weight is attached to the entire tip region on the surface of the vibrating arm 35. In addition, although it is the same also in 1st Embodiment, providing the weight 62 in the surface side of the vibration arm 35 in this way is the positional information regarding the vibration arm 35 through the transparent cover body 39 (refer FIG. 2). The image is recognized and moved to the region to be irradiated by the laser from the edge portion (reference numeral E in FIG. 11) of the excitation electrode 34b on the surface side whose shape is held until the end because the frequency is adjusted finally. This is because the controller calculates the distance.

  As for the tip region on the back surface of the vibrating arm 35, the layer structure is different corresponding to the frequency adjustment region as in the first embodiment, and the excitation electrode 34b as a weight is deposited in the fine adjustment region ER3. In the coarse adjustment region ER2, the weight 56 made of Au (gold) is deposited on the excitation electrode 34b. In the first adjustment region ER1, the weight 56 is formed on the excitation electrode 34b. And the weight 58 which consists of Au (gold) is vapor-deposited, and has a three-layer structure.

Here, the fine adjustment region ER3 is further divided into two regions, one region ER3-2 on the tip side and the other region ER3-1 on the base side, and region ER3-2 and region ER3- 1 and 62 are formed of different materials.
Specifically, the weight 62 provided in one region ER3-2 on the distal end side is formed from the same material (Au in this embodiment) as the weight 62 provided in the other regions ER1 and ER2. Yes. On the other hand, the weight 62 provided in the other region ER3-1 for adjusting the frequency relatively finely as compared with the one region ER3-2 is the Au provided in the one region ER3-2. The film is formed of a material having a smaller mass than (gold) (here, a material having a low density), such as Al (aluminum), Ag (silver), Cr (chromium), Ni (nickel), or the like.

The second embodiment of the present invention is configured as described above, and the region for adjusting the frequency coarsely and the region for finely adjusting the frequency are relatively different in type of the weight 62. By changing, the mass becomes different, and the mass is relatively larger in the region for coarsely adjusting the frequency than in the region for finely adjusting the frequency. Therefore, the same effects as those of the first embodiment are exhibited.
Furthermore, in the second embodiment, compared with the first embodiment, the number of adjustment regions that are divided for each resolution is increased and the number of frequency adjustment steps is increased. It is possible to perform frequency adjustment with a large reduction effect and an efficient frequency, and a fine frequency adjustment with a small mass reduction effect.
Further, the number of adjustment areas divided for each resolution can be increased without increasing the layer structure of the weight 62, and conversely, the number of adjustment areas divided for each resolution can be made the same as in the first embodiment. For example, the layer structure of the weight 62 can be reduced, and the thickness of the vibrating arm 35 including the weight 62 can be reduced. Therefore, for example, the vibrating arm 35 can be prevented from coming into contact with the inner bottom surface of the package.

  The present invention is not limited to the above-described embodiment. The configurations of the embodiments and the modifications may be combined or omitted as appropriate, and may be combined with other configurations not shown.

1 is a schematic plan view of a piezoelectric device according to a first embodiment of the present invention. FIG. 2 is a schematic sectional view taken along line AA in FIG. 1. 1 is a schematic perspective view of a piezoelectric vibrating piece used in a piezoelectric device according to a first embodiment of the present invention. FIG. 4 is a schematic cut end view taken along line BB in FIG. 3. FIG. 3 is a process diagram for explaining the method for manufacturing a piezoelectric device according to the first embodiment of the present invention. The conceptual diagram of the manufacturing process corresponding to the process of FIG. The conceptual diagram of the manufacturing process corresponding to the process of FIG. The conceptual diagram of the manufacturing process corresponding to the process of FIG. FIG. 9A shows a trace of laser beam irradiation on the surface of the vibrating arm, and FIG. 9B shows a trace of laser beam irradiation on the back surface of the vibration arm. It is a modification of 1st Embodiment, Comprising: The schematic longitudinal cross-sectional view of a vibrating arm. FIG. 5 is a schematic longitudinal sectional view of a vibrating arm for a piezoelectric device according to a second embodiment of the present invention, corresponding to the sectional view of FIG. 4. FIG. 6 is a schematic plan view near the tip of a conventional vibrating arm.

Explanation of symbols

  20 ... piezoelectric vibrating piece, 35,36 ... vibrating arm, 37 ... package, 39 ... lid, 45 ... opening, 46 ... sealing material, ER1 ... most Previous adjustment area, ER2 ... coarse adjustment area, ER3 ... fine adjustment area, ER4 ... under-sealing adjustment area, LB1, LB2, LB3, LB4 ... laser beam, 34b, 56, 58, 62 ..Weight

Claims (5)

A piezoelectric vibrating piece provided with a weight irradiated with laser light for frequency adjustment,
The weight has a region for adjusting the frequency relatively coarsely and a region for finely adjusting the frequency,
The region for adjusting the frequency coarsely is formed so as to have a relatively large mass as compared with the region for finely adjusting the frequency.   The region for adjusting the frequency coarsely and the region for finely adjusting the frequency are such that the mass is different by changing the thickness of the weight relatively. The piezoelectric vibrating piece according to claim 1.   The region for adjusting the frequency coarsely and the region for finely adjusting the frequency are such that the mass is different when the type of the weight is relatively changed. The piezoelectric vibrating piece according to claim 1 or 2, characterized in that: A piezoelectric device comprising a package in which an internal space is sealed by a lid, and a piezoelectric vibrating piece accommodated in the internal space of the package,
The lid of the package is made of a material that can transmit laser light,
The piezoelectric vibrating piece is provided with a weight that is irradiated with the laser light so as to pass through the lid.
The weight relatively has a region for adjusting the frequency roughly and a region for finely adjusting the frequency, and the region for adjusting the frequency roughly A piezoelectric device characterized by being formed so as to have a relatively large mass compared to a region for finely adjusting a frequency. An outer shape forming step of forming an outer shape from a piezoelectric material;
A weighting step of attaching a weight to a region irradiated with laser light for frequency adjustment after and / or before the outer shape step,
In the weight attaching step, the weight is attached such that the area for adjusting the frequency relatively coarsely has a larger mass than the area for finely adjusting the frequency. A method for manufacturing a piezoelectric vibrating piece.

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