JP6506535B2 - Piezoelectric vibrating reed and piezoelectric vibrator - Google Patents

Description

  The present invention relates to a piezoelectric vibrating reed and a piezoelectric vibrator.

  For example, in mobile phones and portable information terminals, a piezoelectric vibrator using quartz or the like is often used as a device used as a time source, timing source such as control signal, or reference signal source. As this type of piezoelectric vibrator, one in which a piezoelectric vibrating reed is hermetically sealed in a package in which a cavity is formed is known.

  As a piezoelectric vibrating reed, a so-called center arm type is known. Patent Document 1 describes a so-called center arm type piezoelectric vibrating reed having two vibrating arms connected to each other by a base and provided with electrodes for vibrating.

  By the way, in this type of piezoelectric vibrating reed, two mount electrodes provided on one main surface (mount surface) of the support arm and two systems of excitation electrodes provided on each vibrating arm have their bases They are respectively connected via two series of lead-out electrodes formed via the vias. Moreover, in order to ensure the mutual insulation of two mount electrodes, each mount electrode is arrange | positioned at intervals in the length direction of a support arm. Therefore, on the surface of the support arm, the lead-out electrode connected to the mount electrode located on the distal end side of the support arm passes near the mount electrode located on the proximal end side of the support arm.

  By the way, at the time of mounting the piezoelectric vibrating reed on the package, the conductive bonding material for bonding the mount electrode positioned on the base end side of the support arm is crushed and wet-spreaded. Therefore, when the width dimension of the support arm is narrowed in order to satisfy the demand for downsizing of the piezoelectric vibrating reed, in particular, the mount electrode located on the base end side and the mount electrode located on the tip end side of the support arm There is a possibility that the lead-out electrode connected to may short-circuit through the conductive bonding material.

Japanese Patent Application Publication No. 2003-163568

  Therefore, two sets of lead-out electrodes are respectively formed on both sides in the width direction of the support arm, and the mounts are insulated from each other on the mount surface by drawing around the main surface opposite to the mount surface of the support arm. The electrode and the lead-out electrode can be sufficiently separated. It is thought that this can prevent a short circuit between the mount electrode and the lead-out electrode which are mutually insulated.

  When the lead-out electrode is formed on the side of the support arm as in the above-described piezoelectric vibrating reed, it is necessary to divide the electrode film formed on the side to form two lead-out electrodes. However, since the side surface of the support arm is formed to be orthogonal to the main surface, the side surface can not be sufficiently exposed in the conventional exposure process for forming each electrode, and the electrode film of the side surface is It is difficult to pattern. Therefore, in the prior art, it has been difficult to provide a piezoelectric vibrating reed that can prevent a short circuit during mounting accompanying miniaturization.

  Therefore, the present invention provides a piezoelectric vibrating reed and a piezoelectric vibrator capable of preventing a short circuit at the time of mounting accompanying miniaturization.

The piezoelectric vibrating reed of the present invention extends along the longitudinal direction of the pair of vibrating arms, the pair of vibrating arms disposed side by side, the base connecting the proximal ends of the pair of vibrating arms, and the base A support arm connected to the base by the base end, and a pair of mount electrodes disposed on the main surface of the support arm at intervals in the longitudinal direction, the support arm comprising: And a tapered surface which is inclined with respect to the thickness direction of the support arm in a region corresponding to the pair of mount electrodes on the side surface.
According to the present invention, since the tapered surface formed on the side surface of the support arm is inclined with respect to the thickness direction of the support arm, the electrode film is formed on the tapered surface when it is patterned by photolithography. It becomes possible to expose the resist film on the formed electrode film from the thickness direction of the support arm. Thereby, since it is not necessary to expose from the side of a support arm part, the increase in the man-hour of the exposure at the time of electrode formation can be suppressed. And since a taper surface is formed in the position corresponding between a pair of mount electrodes in the side of a support arm, it connects to each mount electrode and mutually insulates the electrode wound around the side of a support arm It can be patterned in the Therefore, the piezoelectric vibrating reed which can prevent the short circuit at the time of mounting accompanying size reduction is obtained.

In the piezoelectric vibrating reed described above, the support arm portion includes a deformed portion protruding from the side surface, and the tapered surface is formed on the deformed portion.
Generally, in the deformed portion generated by the etching residue, the crystal surface appears as a tapered surface. Therefore, according to the present invention, it is possible to easily form a support arm having a tapered surface on the side surface.

In the above-described piezoelectric vibrating reed, a step portion is formed on the side surface of the support arm portion, and the deformed portion is formed in the step portion.
In general, the etching residue has a property that it tends to be significantly generated in a small portion of the gap. Therefore, according to the present invention, by forming the step portion on the side surface of the support arm portion, the deformed portion can be easily formed at the corner portion of the step portion.

In the above-mentioned piezoelectric vibrating reed, the supporting arm portion is characterized in that a notch is formed in a part of the side surface on the more proximal side than the pair of mount electrodes.
According to the present invention, the vibration excited by the vibrating arm can narrow the route propagating to the supporting arm via the base, so that the vibration can be confined in the vibrating arm. As a result, it is possible to effectively suppress the vibration leakage of the miniaturized piezoelectric vibrating reed, to suppress the increase of the CI value, and to suppress the deterioration of the quality of the output signal.

In the above-described piezoelectric vibrating reed, the support arm is disposed between the pair of vibrating arms.
According to the present invention, the vibration characteristics can be improved because the pair of vibrating vibrating arms are arranged symmetrically about the support arm fixed to the package. In addition, since it is not necessary to provide a fixing portion to the package on the base, the length of the piezoelectric vibrating reed can be shortened, and the piezoelectric vibrating reed can be miniaturized.

A piezoelectric vibrator according to the present invention includes the above-described piezoelectric vibrating reed.
According to the present invention, since the piezoelectric vibrating reed can prevent a short circuit at the time of mounting accompanying miniaturization, a small-sized piezoelectric vibrator excellent in reliability can be obtained.

  According to the present invention, since the tapered surface formed on the side surface of the support arm is inclined with respect to the thickness direction of the support arm, the electrode film is formed on the tapered surface when it is patterned by photolithography. It becomes possible to expose the resist film on the formed electrode film from the thickness direction of the support arm. Thereby, since it is not necessary to expose from the side of a support arm part, the increase in the man-hour of the exposure at the time of electrode formation can be suppressed. And since a taper surface is formed in the position corresponding between a pair of mount electrodes in the side of a support arm, it connects to each mount electrode and mutually insulates the electrode wound around the side of a support arm It can be patterned in the Therefore, the piezoelectric vibrating reed which can prevent the short circuit at the time of mounting accompanying size reduction is obtained.

It is an external appearance perspective view of a piezoelectric vibrator. It is an internal block diagram of a piezoelectric vibrator. It is sectional drawing in the III-III line of FIG. It is an exploded perspective view of a piezoelectric vibrator. FIG. 2 is a plan view of the piezoelectric vibrating reed according to the first embodiment. FIG. 2 is a plan view of the piezoelectric vibrating reed according to the first embodiment. It is sectional drawing in the VII-VII line of FIG. It is sectional drawing in the VIII-VIII line of FIG. It is a flowchart which shows the manufacturing method of the piezoelectric vibrating piece which concerns on 1st Embodiment. FIG. 6 is a plan view of another piezoelectric vibrating reed according to the first embodiment. FIG. 6 is a plan view of another piezoelectric vibrating reed according to the first embodiment. FIG. 6 is a plan view of another piezoelectric vibrating reed according to the first embodiment. FIG. 6 is a plan view of another piezoelectric vibrating reed according to the first embodiment. FIG. 6 is a plan view of another piezoelectric vibrating reed according to the first embodiment. FIG. 7 is a plan view of a piezoelectric vibrating reed according to a modification of the first embodiment. FIG. 7 is a plan view of a piezoelectric vibrating reed according to a second embodiment. FIG. 7 is a plan view of a piezoelectric vibrating reed according to a second embodiment.

Hereinafter, embodiments of the present invention will be described based on the drawings.
(First Embodiment, Piezoelectric Vibrator)
FIG. 1 is an external perspective view of a piezoelectric vibrator. FIG. 2 is an internal configuration view of the piezoelectric vibrator, and is a view of the piezoelectric vibrating reed from above with the sealing plate removed. FIG. 3 is a cross-sectional view taken along line III-III of FIG. FIG. 4 is an exploded perspective view of the piezoelectric vibrator.

  As shown in FIGS. 1 to 4, the piezoelectric vibrator 1 according to this embodiment includes a package 2 having a cavity C hermetically sealed therein and a tuning fork type piezoelectric vibrating reed 3 housed in the cavity C. , And a ceramic package type surface-mounted oscillator.

The package 2 includes a package body 5 and a sealing plate 6 joined to the package body 5 and forming a cavity C with the package body 5.
The package body 5 includes a first base substrate 10 and a second base substrate 11 joined in a state of being superimposed on each other, and a seal ring 12 joined onto the second base substrate 11.

At the four corners of the first base substrate 10 and the second base substrate 11, notch portions 15 having a quarter arc shape in plan view are formed over the entire thickness direction of both the base substrates 10 and 11. The first base substrate 10 and the second base substrate 11 are formed, for example, by stacking and bonding two wafer-shaped ceramic substrates, and then forming a plurality of through holes penetrating both ceramic substrates in a matrix. It is produced by cutting both ceramic substrates in a grid while using the holes as a reference. At this time, the through hole is divided into four to form the notch portion 15.
The upper surface of the second base substrate 11 is a mounting surface 11 a corresponding to the inner wall on which the piezoelectric vibrating reed 3 is mounted.

  Although the first base substrate 10 and the second base substrate 11 are made of ceramics, as a specific ceramic material, for example, HTCC (High Temperature Co-Fired Ceramic) made of alumina or LTCC (made of glass ceramic) Low Temperature Co-Fired Ceramic) and the like.

  The seal ring 12 is a conductive frame-like member which is slightly smaller than the outline of the first base substrate 10 and the second base substrate 11, and is joined to the mounting surface 11 a of the second base substrate 11. Specifically, the seal ring 12 is joined on the mounting surface 11a by baking with a brazing material such as silver solder or a solder material, or formed on the mounting surface 11a (for example, in addition to electrolytic plating and electroless plating) They are joined by welding or the like to a metal joining layer deposited by evaporation, sputtering or the like.

In addition, as a material of the seal ring 12, a nickel base alloy etc. are mentioned, for example, and what is necessary is just to select from Kovar, an elin bar, Invar, 42- alloy etc. specifically ,. In particular, as the material of the seal ring 12, it is preferable to select one having a thermal expansion coefficient close to that of the first base substrate 10 and the second base substrate 11 made of ceramic. For example, when alumina having a thermal expansion coefficient of 6.8 × 10 ⁻⁶ / ° C. is used as the first base substrate 10 and the second base substrate 11, the seal ring 12 has a thermal expansion coefficient of 5.2 × 10 ⁻ Kovar or ⁶ / ° C., it is preferable to use a thermal expansion coefficient of 4.5~6.5 × 10 ^-6 / ℃ 42-alloy.

  The sealing plate 6 is a conductive substrate stacked on the seal ring 12 and is airtightly bonded to the package body 5 by bonding to the seal ring 12. A space defined by the sealing plate 6, the seal ring 12 and the mounting surface 11 a of the second base substrate 11 functions as the cavity C hermetically sealed.

  In addition, as a welding method of the sealing board 6, the seam welding by making a roller electrode contact, laser welding, ultrasonic welding etc. are mentioned, for example. Further, in order to make the welding between the sealing plate 6 and the seal ring 12 more reliable, bonding layers made of nickel, gold or the like which are compatible with each other at least on the lower surface of the sealing plate 6 and the upper surface of the seal ring 12 It is preferable to form.

  By the way, on the mounting surface 11 a of the second base substrate 11, a pair of electrode pads 20 A and 20 B that are connection electrodes with the piezoelectric vibrating reed 3 are formed at intervals in the longitudinal direction of the piezoelectric vibrator 1. A pair of external electrodes 21A and 21B are formed on the lower surface of the first base substrate 10 at intervals in the longitudinal direction of the piezoelectric vibrator 1. The electrode pads 20A and 20B and the external electrodes 21A and 21B are, for example, single-layered films of a single metal formed by vapor deposition, sputtering or the like, or laminated films in which different metals are laminated, and are mutually conducted.

  That is, in the first base substrate 10, one first through electrode 22A which is electrically connected to the one external electrode 21A and penetrates the first base substrate 10 in the thickness direction is formed. The second base substrate 11 is formed with one second through electrode 23A which is electrically connected to one of the electrode pads 20A and penetrates the second base substrate 11 in the thickness direction. Further, one connection electrode 24A is formed between the first base substrate 10 and the second base substrate 11 to connect one first through electrode 22A and one second through electrode 23A. Thereby, one electrode pad 20A and one external electrode 21A are electrically connected to each other.

Further, the first base substrate 10 is formed with the other first through electrode 22B which is electrically connected to the other external electrode 21B and penetrates the first base substrate 10 in the thickness direction. Further, the second base substrate 11 is formed with the other second through electrode 23B which is electrically connected to the other electrode pad 20B and penetrates the second base substrate 11 in the thickness direction. The other connection electrode 24B is formed between the first base substrate 10 and the second base substrate 11 to connect the other first through electrode 22B and the other second through electrode 23B. Thereby, the other electrode pad 20B and the other external electrode 21B are electrically connected to each other.
The other connection electrode 24B is patterned to extend, for example, along the seal ring 12 below the seal ring 12 so as to avoid a recess 17 described later.

  Recesses 17 are formed on the mounting surface 11 a of the second base substrate 11 at portions facing the tips 31 a and 32 a of a pair of vibrating arms 31 and 32 of the piezoelectric vibrating reed 3 described later. The recess 17 avoids contact with the tips 31a and 32a of the vibrating arms 31 and 32 when the vibrating arms 31 and 32 are displaced (flexural deformation) in the thickness direction due to the impact of a drop or the like. It is for. The concave portion 17 is a through hole penetrating the second base substrate 11 and is formed in a rectangular shape in plan view in which four corners are rounded on the inner side of the seal ring 12.

(Piezoelectric vibrator)
FIG. 5 is a plan view of the piezoelectric vibrating reed according to the first embodiment, and is a plan view when viewed from the mounting surface side in a state of being mounted on a package. FIG. 6 is a plan view of the piezoelectric vibrating reed according to the first embodiment, and is a plan view as viewed from the sealing plate side in a state of being mounted on a package. In FIG. 5 and FIG. 6, for the sake of clarity, the electrodes 51 to 56 described later are hatched for convenience.
The piezoelectric vibrating reed 3 is a tuning fork type vibrating reed formed of a piezoelectric material such as quartz crystal, lithium tantalate or lithium niobate, and vibrates when a predetermined voltage is applied. In the following description, quartz is taken as an example of the piezoelectric material. As shown in FIGS. 5 and 6, the piezoelectric vibrating reed 3 extends in a predetermined direction, and a pair of vibrating arms 31 and 32 arranged in a row, and a proximal end 31b of the pair of vibrating arms 31 and 32, It has a base 33 which connects 32b, and a support arm 34 whose base end is connected to the base 33 between the pair of vibrating arms 31, 32.

  In the following, when describing the configuration of the piezoelectric vibrating reed 3, the juxtaposing direction of the pair of vibrating arm portions 31, 32 is the X direction, and the longitudinal direction of the pair of vibrating arm portions 31, 32 is the Y direction, the X direction and The direction orthogonal to the Y direction (thickness direction of the support arm 34) is taken as the Z direction. Here, in the X direction, the vibrating arm 32 side with respect to the support arm 34 is + X side, and the vibrating arm 31 side with respect to the support arm 34 is −X side. Further, in the Y direction, the distal end sides of the vibrating arm portions 31 and 32 are set to the + Y side, and the proximal end sides of the vibrating arm portions 31 and 32 are set to the −Y side. Further, among the main surfaces of the piezoelectric vibrating reed 3 in the Z direction, the main surface facing the mounting surface 11 a of the package 2 (the main surface shown in FIG. 5; hereinafter referred to as the “mount surface”) is the −Z side. The opposite main surface (main surface shown in FIG. 6. Hereinafter, referred to as “anti-mount surface”) side is the + Z side.

  As shown in FIG. 5, the pair of vibrating arms 31 and 32 extend parallel to each other along the Y direction, and the proximal ends 31b and 32b in the Y direction are fixed ends, and the distal ends 31a and 32a are free ends Vibrate as. The pair of vibrating arms 31 and 32 is, for example, a hammerhead type in which the width on the distal end 31a or 32a side is enlarged compared to the proximal end 31b or 32b, and the distal end 31a or 32a of the vibrating arm 31 or 32 The weight on the side and the moment of inertia when vibrating are increased. As a result, the vibrating arms 31 and 32 easily vibrate, and the lengths of the vibrating arms 31 and 32 can be shortened, thereby achieving downsizing. The length of the pair of vibrating arms 31 and 32 is, for example, about 1 mm. The pair of vibrating arms 31 and 32 is not limited to the hammer head type.

7 is a cross-sectional view taken along line VII-VII of FIG.
As shown in FIG. 7, the pair of vibrating arms 31 and 32 includes grooves 41 formed along the Y direction on both main surfaces 31 c and 32 c on both sides in the thickness direction (Z direction). . As shown in FIGS. 5 and 6, the groove 41 is formed, for example, from the base ends 31b and 32b of the vibrating arms 31 and 32 to a portion where the width on the tip 31a or 32a side is enlarged. .

  On the surfaces of the pair of vibrating arms 31, 32, two systems of first excitation electrode 51 and second excitation electrode 52 (hereinafter referred to as “each of them” which vibrate these vibrating arms 31, 32 in the width direction (X direction) Sometimes referred to as “excitation electrodes 51, 52”. The respective excitation electrodes 51, 52 are patterned on the surfaces of the pair of vibrating arms 31, 32 in a state electrically insulated from each other, and can vibrate the pair of vibrating arms 31, 32 at a predetermined frequency. It is arranged as

  The first excitation electrode 51 is continuously provided on the groove 41 of the vibrating arm 31 and on both side surfaces 32 d and 32 e (see FIG. 7) of the vibrating arm 32 and in the vicinity of the tip 32 a. Specifically, the first excitation electrode 51 has a partial electrode 51 a formed on the groove portion 41 on the non-mount surface side (+ Z side) and a groove portion 41 on the mount surface side (−Z side) on the vibrating arm portion 31. And a partial electrode 51b formed on the In addition, the first excitation electrode 51 includes a partial electrode 51c formed on the side surface 32d opposite to the support arm 34 on the vibrating arm 32, and a partial electrode 51d formed on the outer side surface 32e. Have.

  The second excitation electrode 52 is provided continuously on both side surfaces 31 d and 31 e (see FIG. 7) of the vibrating arm 31 and in the vicinity of the tip 31 a and on the groove 41 of the vibrating arm 32. Specifically, on the vibrating arm 31, the second excitation electrode 52 is a partial electrode 52a formed on the side 31d facing the support arm 34 and a partial electrode 52b formed on the outer side 31e. And. In addition, the second excitation electrode 52 is formed on the vibrating arm 32 in the partial electrode 52c formed in the groove 41 on the non-mount surface side (+ Z side) and in the groove 41 on the mount surface side (−Z side). And a partial electrode 52d.

  The base 33 is formed in a rectangular shape extending along the X direction. The base 33 has a length in the X direction of, for example, about 0.5 mm. The base ends 31 b and 32 b of the pair of vibrating arms 31 and 32 are integrally connected and fixed to the base 33.

  The support arm 34 has a narrow portion 35 extending along the Y direction, and a wide portion 36 extending from the end on the + Y side of the narrow portion 35 toward the + Y side. The narrow portion 35 is connected to the approximate center of the base 33 in the X direction at an end on the −Y side. The wide portion 36 is connected to the narrow portion 35 substantially at the center in the X direction on the side on the −Y side as viewed from the Z direction. Thus, the wide portion 36 forms a pair of step portions 37 between the side surfaces of the narrow portion 35 in the X direction.

FIG. 8 is a cross-sectional view taken along line VIII-VIII of FIG.
The support arm portion 34 includes a first deformed portion 38 and a second deformed portion 39 (hereinafter sometimes referred to as “respective deformed portions 38 and 39”) protruding from the side surface in each step portion 37.
As shown in FIG. 8, the first deformed portion 38 is triangular in cross section, and has a pair of planar tapered surfaces 38 a inclined with respect to the Z direction. As shown in FIGS. 5 and 8, of the pair of tapered surfaces 38a, the tapered surface 38a on the −Z side is connected to the mounting surface 34a of the support arm 34 at the corner of the step 37 and It inclines toward + Z direction according to -Y) direction. As shown in FIGS. 6 and 8, of the pair of tapered surfaces 38a, the + Z-side tapered surface 38a is connected to the non-mounting surface 34b of the support arm 34 at the corner of the step 37 and As it goes in the -Y) direction, it inclines in the -Z direction. And as for a pair of taper surface 38a, the end sides by the side of (+ X, -Y) are connected. As shown in FIG. 5, according to the above configuration, the first deformed portion 38 is formed to fill the corner of the step portion 37 on the + X side as viewed from the Z direction.

  Further, as shown in FIGS. 5 and 8, the second deformed portion 39 is formed in the same manner as the first deformed portion 38, and has a pair of planar tapered surfaces 39a inclined with respect to the Z direction. The second deformed portion 39 is formed to fill the corner of the step portion 37 on the −X side when viewed from the Z direction.

  Each of the deformed portions 38 and 39 is an etching residue formed at the time of wet etching which forms the outer shape of the piezoelectric vibrating reed 3 described later. The etching residue is formed by the nature that quartz has a different etching rate for each crystal axis. Therefore, the tapered surface 38a of the first deformed portion 38 and the tapered surface 39a of the second deformed portion 39 (hereinafter sometimes referred to as "each tapered surface 38a, 39a") are formed of natural crystal planes of quartz crystal. There is.

  As shown in FIG. 5, on the mount surface 34a of the support arm 34, the first mount electrode 53 and the second mount electrode 54 (hereinafter referred to as "each mount electrode 53, 54") are disposed separately in the Y direction. There is a case). The mount electrodes 53 and 54 function as mounts when the piezoelectric vibrating reed 3 is mounted on the package 2. The first mount electrode 53 is formed on the narrow portion 35 of the support arm 34 and is disposed at a position not overlapping the deformed portions 38 and 39 in the Y direction. The second mount electrode 54 is formed on the wide portion 36 of the support arm 34, and is disposed at a position not overlapping the deformed portions 38 and 39 in the Y direction. The mount electrodes 53 and 54 are disposed on the mount surface 34 a of the support arm 34 over the entire X direction.

  As shown in FIGS. 5 and 6, the first mount electrode 53 and the first excitation electrode 51 are connected in the path from the support arm 34 to the pair of vibrating arms 31 and 32 via the base 33. A first lead-out electrode 55 and a second lead-out electrode 56 for connecting the second mount electrode 54 and the second excitation electrode 52 are provided.

  The first lead-out electrode 55 has partial electrodes 55a to 55j. The partial electrode 55 a is continuous with the side on the −X side of the first mount electrode 53, and is formed on the side surface on the −X side of the narrow portion 35. At this time, the partial electrode 55 a is formed only on the surface along the Z direction in the region on the + Y side of the side surface on the −X side of the narrow portion 35. That is, the partial electrode 55 a is formed excluding the tapered surface 39 a of the second deformed portion 39. As shown in FIG. 6, a partial electrode 55b which is continuous with the partial electrode 55a and overlaps the region on the -X side of the first mount electrode 53 in the Z direction as viewed on the anti-mount surface 34b of the narrow portion 35. Is formed. Furthermore, a partial electrode 55c extending along the Y direction from the partial electrode 55b to the base 33 is formed on the non-mount surface 34b of the narrow portion 35. A partial electrode 55d connecting the end on the -Y side of the partial electrode 55c and the end on the -Y side of the partial electrode 51a of the first excitation electrode 51 is formed on the anti-mount surface of the base 33 .

  As shown in FIGS. 5 and 6, the partial electrode 55 e of the first lead-out electrode 55 is continuous with the side on the + X side of the first mount electrode 53 and is formed on the side surface of the narrow portion 35. At this time, the partial electrode 55 e is formed only on the surface along the Z direction in the region on the + Y side of the side surface on the + X side of the narrow portion 35. That is, the partial electrode 55 e is formed excluding the tapered surface 38 a of the first deformed portion 38. As shown in FIG. 6, a partial electrode 55f overlapping the region on the + X side of the first mount electrode 53 in the Z direction as viewed from the Z direction is made continuous with the partial electrode 55e and on the anti-mount surface 34b in the narrow portion 35. It is formed. Furthermore, a partial electrode 55g extending along the Y direction from the partial electrode 55f to the base 33 is formed on the non-mount surface 34b of the narrow portion 35. A partial electrode 55h connecting the end on the -Y side of the partial electrode 55g and the end on the -Y side of the partial electrode 51c of the first excitation electrode 51 is formed on the anti-mount surface of the base 33 .

  Further, as shown in FIG. 5, on the mount surface 34 a of the narrow portion 35, a partial electrode 55 i is formed which protrudes toward the base 33 from the side on the −Y side of the first mount electrode 53. Furthermore, on the mount surface of the base 33, a partial electrode 55j connecting the end on the -Y side of the partial electrode 55i and the pair of ends on the -Y side of the partial electrodes 51b and 51c of the first excitation electrode 51 Is formed.

  As shown in FIGS. 5 and 6, the second lead-out electrode 56 has partial electrodes 56a to 56e. The partial electrode 56 a is formed on the side surface of the wide portion 36 so as to be continuous with the side on the + Y side of the second mount electrode 54 and the side on both sides in the X direction. At this time, the partial electrode 56 a is formed only on the surface along the Z direction on the side surface on the −Y side of the wide portion 36. That is, the partial electrodes 56a are formed excluding the tapered surfaces 38a and 39a.

As shown in FIG. 6, on the opposite mounting surface 34b of the wide portion 36, a partial electrode 56b that is continuous with the partial electrode 56a and that overlaps with the second mount electrode 54 in the Z direction is formed. Furthermore, on the non-mount surface 34b of the support arm 34, a partial electrode 56c that protrudes in the Y direction from the center of the side on the -Y side of the partial electrode 56b toward the base 33 is formed. The partial electrode 56c passes between the partial electrodes 55b and 55c of the first lead-out electrode 55 and the partial electrodes 55f and 55g. On the opposite mounting surface of the base 33, a partial electrode 56d connecting the end on the -Y side of the partial electrode 56c and the pair of ends on the -Y side of the partial electrodes 52b and 52c of the second excitation electrode 52 It is formed.
Further, as shown in FIG. 5, on the mount surface of the base 33, a partial electrode 56e is formed to connect a pair of end portions on the -Y side of the partial electrodes 52b and 52d of the second excitation electrode 52. .

The first lead-out electrode 55 and the second lead-out electrode 56 (hereinafter sometimes referred to as “the lead-out electrodes 55, 56”) formed as described above are patterned in a mutually insulated state. At the time of the exposure which patterns each electrode 51-56 mentioned later, each taper surface 38a and 39a which inclines with respect to a Z direction can also be exposed by irradiation of the ultraviolet light from a Z direction. At this time, since each of the tapered surfaces 38a and 39a is connected to the mounting surface 34a and the non-mounting surface 34b, the area to be exposed at the time of the exposure is the opposite surface from the mounting surface 34a It can be provided continuously to 34b. As a result, the lead-out electrodes 55 and 56 are divided into the distal end side and the proximal end side on the side surface of the support arm 34.
The conductive portion from the first mount electrode 53 to the first excitation electrode 51 via the first lead-out electrode 55 is formed by continuous patterning. The conductive portion from the second mount electrode 54 to the second excitation electrode 52 via the second lead-out electrode 56 is formed by being continuously patterned.

  As shown in FIGS. 2 to 4, the piezoelectric vibrating reed 3 configured as described above is accommodated in the cavity C of the hermetically sealed package 2, and the mounting surface of the support arm 34 of the piezoelectric vibrating reed 3 is provided. Mounting electrodes 53 and 54 (see FIG. 5) provided on 34a are electrically conductively attached to two electrode pads 20A and 20B provided on the mounting surface 11a of the second base substrate 11 of the package 2 respectively. Electrically and mechanically joined. Thus, the piezoelectric vibrating reed 3 is supported by the support arm 34 in a floating state from above the mounting surface 11 a of the second base substrate 11, and the base end 31 b of the pair of vibrating arms 31 and 32 via the base 33. , 32b side is supported in a cantilever manner.

  Then, when a predetermined voltage is applied to the external electrodes 21A and 21B, a current flows through the respective excitation electrodes 51 and 52, and the pair of vibrating arm portions 31 and 32 are generated by the interaction between the respective excitation electrodes 51 and 52, For example, it vibrates at a predetermined resonance frequency in a direction (X direction) in which they approach and separate from each other. The vibrations of the pair of vibrating arms 31 and 32 are used as a time source, a timing source of control signals, a reference signal source, and the like.

  In addition, it is also possible to use a metal bump instead of the conductive adhesive as a conductive bonding material for bonding the mount electrodes 53 and 54 to the electrode pads 20A and 20B. The common point of the conductive adhesive and the metal bump is that it is a conductive bonding material that has fluidity at the initial stage of bonding and solidifies at the latter stage of bonding to develop bonding strength.

First Embodiment, Method of Manufacturing Piezoelectric Vibrating Piece
Hereinafter, a method of manufacturing the piezoelectric vibrating reed 3 of the present embodiment will be described. In addition, please refer to FIG. 5 and FIG. 6 for the code | symbol of each component in the following description.
FIG. 9 is a flowchart showing a method of manufacturing the piezoelectric vibrating reed according to the first embodiment.

  As shown in FIG. 9, in the method of manufacturing the piezoelectric vibrating reed 3 of the present embodiment, an outer shape forming step S1 of forming a piezoelectric plate having the outer shape of the piezoelectric vibrating reed 3 from a wafer made of piezoelectric material; A groove forming process S3 for forming a groove on the arm, an electrode film forming process S5 for forming an electrode film on a piezoelectric plate, a resist film forming process S7 for forming a photoresist film on the surface of the electrode film, An exposure process S9 for exposing the resist film, an etching process S11 for etching the electrode film, and a resist stripping process S13 for removing the photoresist film are included.

(Outline formation process)
First, an outer shape forming step S1 is performed. In the outer shape forming step S1, a piezoelectric plate having the outer shape of the piezoelectric vibrating reed 3 is formed from a wafer made of a piezoelectric material.
Specifically, first, an etching protective film and a photoresist film are sequentially formed on both sides of the wafer. Next, the photoresist film is exposed using the photomask for forming an outer shape on which the outer pattern of the piezoelectric vibrating reed 3 is formed, and the outer pattern of the piezoelectric vibrating reed 3 is formed on the photoresist film. The light blocking pattern of the photomask for forming an outer shape corresponds to the shape of the outer shape of the piezoelectric vibrating reed 3 in the Z direction as viewed from the region excluding the deformed portions 38 and 39.

Next, the etching protection film is etched using the photoresist film on which the outer shape pattern of the piezoelectric vibrating reed 3 is formed as a mask to form an outer shape mask of the outer shape pattern of the piezoelectric vibrating reed 3 by the etching protective film on both sides of the wafer. The shape of the outer shape mask in the Z direction is the same as the shape of the outer shape of the piezoelectric vibrating reed 3 except for the deformed portions 38 and 39 in the Z direction. By wet etching the wafer using this outer shape mask, a piezoelectric plate having the outer shape of the piezoelectric vibrating reed 3 is formed.
At this time, an etching residue is formed on the piezoelectric plate. The etching residue has a property of being easily generated in a small portion of the gap. For this reason, in the present embodiment, the etching residue is formed at each corner of the stepped portion 37 formed by the narrow portion 35 and the wide portion 36 as the different shaped portions 38 and 39. The tapered surfaces 38a and 39a of the deformed portions 38 and 39 are formed of natural crystal surfaces of quartz crystal as described above, and the surface direction is inclined with respect to the Z direction.
Then, the etching protective film and the photoresist film are removed.

(Groove formation process)
Next, a groove forming step S3 is performed. In the groove forming step S3, the groove 41 is formed on the vibrating arms 31 and 32 of the piezoelectric plate.
Specifically, an etching protective film and a photoresist film are formed in order again on the entire surface of the piezoelectric plate. Then, using the groove forming photomask in which the outer pattern of the groove 41 is formed as the light shielding pattern, the outer mask of the groove 41 with the etching protective film is formed as in the outer mask forming in the outer forming process S1. Next, half etching is performed on the piezoelectric plate to form a groove 41. Thereafter, the etching protection film and the photoresist film are removed to form a piezoelectric plate provided with the groove 41.

(Electrode deposition process)
Next, an electrode film formation step S5 is performed. In the electrode film forming step S5, an electrode film is formed on the entire surface of the piezoelectric plate by a sputtering method, a vapor deposition method, or the like. The electrode film is formed of a single layer film of a metal such as gold or a laminated film having a metal such as chromium as a base layer and a metal such as gold as an upper layer.

(Resist film formation process)
Next, a resist film formation step S7 is performed. In the resist film forming step S7, a resist material is applied to the surface of the electrode film by spin coating or the like to form a photoresist film. This resist material is a compound based on a resin having photosensitivity to ultraviolet light, and in the present embodiment, a so-called positive type photoresist is adopted, which can soften and remove the exposed part.

(Exposure process)
Next, an exposure step S9 is performed. In the exposure step S9, the photoresist film on both main surfaces of the piezoelectric plate is exposed from both sides in the Z direction.
Specifically, first, a photoresist film on the + Z-side main surface of the piezoelectric plate is exposed to ultraviolet light along the Z direction using a first photomask for electrode formation. The light shielding pattern in the first electrode forming photomask corresponds to the shape of each of the electrodes 51 to 56 on the anti-mount surface of the piezoelectric vibrating reed 3. At this time, among the piezoelectric plates, the side surfaces along which the surface direction is along the Z direction are not exposed, while the tapered surfaces 38a and 39a whose surface direction is inclined to the Z direction are exposed.

  Next, ultraviolet light is exposed along the Z direction to the photoresist film on the main surface on the −Z side of the piezoelectric plate using a second photomask for electrode formation. The light blocking pattern in the second electrode forming photomask matches the shape of each of the electrodes 51 to 56 on the mount surface of the piezoelectric vibrating reed 3. At this time, as in the case of the exposure using the first electrode-forming photomask, the side surface of the piezoelectric plate along the Z direction is not exposed while the surface direction is inclined to the Z direction. Each tapered surface 38a, 39a is exposed.

  After exposing the photoresist film, unnecessary portions (exposed portions) of the photoresist film are removed by a developer, and the photoresist film is solidified through a heating process and the like. Thus, an etching mask having a shape corresponding to the electrode pattern is formed on the outer surface of the piezoelectric plate.

(Etching process)
Next, an etching step S11 is performed. In the etching step S11, the electrode film is etched through the etching mask to selectively remove the unmasked electrode film. In this etching process, a wet etching method can be used in which a piezoelectric plate on which an electrode film and an etching mask are formed is immersed in a chemical solution.
At this time, since the electrode films are exposed on the tapered surfaces 38a and 39a, the electrode films on the tapered surfaces 38a and 39a are completely removed by etching. Thereby, the electrode film on the side surface of the support arm 34 is divided into the narrow portion 35 side and the wide portion 36 side with the deformed portions 38 and 39 interposed therebetween, and the lead-out electrodes 55 and 56 are insulated from each other. It can be patterned.

(Resist peeling process)
Next, a resist peeling step S13 is performed. In the resist peeling step S13, the etching mask is removed. Thereby, as shown in FIG. 5 and FIG. 6, the piezoelectric vibrating reed 3 is formed.
Thus, the manufacture of the piezoelectric vibrating reed 3 is completed.

As described above, in the piezoelectric vibrating reed 3 of the present embodiment, the support arm 34 is tapered in the region corresponding to the side surface between the first mount electrode 53 and the second mount electrode 54 on the side surface with respect to the Z direction. It has faces 38a and 39a.
According to this configuration, the tapered surfaces 38a and 39a formed on the side surfaces of the support arm 34 are inclined with respect to the Z direction. Therefore, when the electrode film is patterned by photolithography, the tapered surfaces are formed. It becomes possible to expose the resist film on the electrode film formed on 38a and 39a from the Z direction. Thereby, since it is not necessary to perform exposure from the side of the support arm 34, it is possible to suppress an increase in the number of steps of exposure at the time of electrode formation. Since each tapered surface 38 a, 39 a is formed at a position corresponding to the position between the mount electrodes 53, 54 on the side surface of the support arm 34, each lead-out electrode 55 drawn around the side surface of the support arm 34. , 56 can be patterned in a mutually insulated state. Therefore, the piezoelectric vibrating reed 3 which can prevent the short circuit at the time of mounting accompanying size reduction is obtained.

Further, the piezoelectric vibrating reed 3 of the present embodiment includes the different shaped portions 38 and 39 in which the support arm 34 protrudes from the side surface, and the tapered surfaces 38 a and 39 a are formed in the different shaped portions 38 and 39.
Generally, in each deformed portion 38, 39 generated by the etching residue, the natural crystal surface of the quartz crystal appears as each tapered surface 38a, 39a. Therefore, the supporting arm 34 having each tapered surface 38a, 39a on the side is easily formed. can do.

Further, in the piezoelectric vibrating reed 3 of the present embodiment, the step portion 37 is formed on the side surface of the support arm portion 34, and the different shaped portions 38 and 39 are formed in the step portion 37.
In general, the etching residue has a property that it tends to be significantly generated in a small portion of the gap. Therefore, by forming the step portion 37 on the side surface of the support arm portion 34, the different shaped portions 38 and 39 can be easily formed at the corners of the step portion 37.

Further, in the piezoelectric vibrating reed 3 of the present embodiment, the support arm 34 is disposed between the pair of vibrating arms 31 and 32.
According to this configuration, since the pair of vibrating arm portions 31 and 32 that vibrate is disposed symmetrically with respect to the support arm portion 34 fixed to the package 2, the vibration characteristics can be improved. Further, since it is not necessary to provide the base portion 33 with a fixing portion to the package 2, the length of the piezoelectric vibrating reed 3 can be shortened, and the piezoelectric vibrating reed 3 can be miniaturized.

  The piezoelectric vibrator 1 of the present embodiment includes the piezoelectric vibrating reed 3. Since the piezoelectric vibrating reed 3 can prevent a short circuit at the time of mounting accompanying miniaturization, a small-sized piezoelectric vibrator excellent in reliability can be obtained.

The shape of the support arm portion 34 of the piezoelectric vibrating reed 3 is not limited to the above shape.
10 to 14 are plan views of another piezoelectric vibrating reed according to the first embodiment, as viewed from the mount surface side.

The step portion 37 of the support arm portion 34 in the piezoelectric vibrating reed 3 shown in FIGS. 5 and 6 is formed in a one-step step shape having vertical corners and corner portions in the Z direction view.
On the other hand, as shown in FIG. 10, the step portion 37 of the support arm portion 34 may be formed in a step shape having sharp corners and corner portions in the Z direction view. According to this shape, since the corner of the step portion 37 is narrowed, it is possible to more reliably form each of the deformed portions 38 and 39 (remaining etching) which are likely to be significantly generated in the small gap.
Further, as shown in FIG. 11, the step portion 37 of the support arm portion 34 may be formed into a plurality of steps in a Z direction view. According to this shape, the deformed portions 38 and 39 are formed in accordance with the number of steps of the step portion 37, so that each of the lead-out electrodes 55 and 56 on the side surface of the support arm 34 It can be divided more reliably between each other.

Further, the support arm portion 34 of the piezoelectric vibrating reed 3 shown in FIGS. 5 and 6 has a proximal end side (narrow portion 35) with the width of the distal end side (wide portion 36) via the step portion 37 in the Z direction It was formed in the shape of a thick, wider than the width of.
On the other hand, as shown in FIG. 12, even if the support arm 34 is formed in a tapered shape, the width on the tip end side is narrower than the width on the base end side via the step portion 37 in the Z direction. Good. According to this shape, since the width at the base end of the support arm 34 can be secured wide, the mechanical strength at the connection portion between the support arm 34 and the base 33 can be enhanced. In this case, as shown in FIG. 13, the corners and the corners of the step portion 37 may have obtuse angles.
Further, as shown in FIG. 14, the support arm 34 is formed in a crank shape in which the central axis in the extension direction is shifted in the X direction between the distal end side and the proximal end side via the step portion 37 in the Z direction view It may be done. According to this shape, since the width of the support arm portion 34 is narrowed between the pair of step portions 37, the conductive adhesive which wets and spreads on the mount surface 34 a when mounted on the package 2 is the same as that of the pair of step portions 37. It is possible to suppress the spread of wetting beyond the interval.

(Modification of First Embodiment, Piezoelectric Vibrating Piece)
Next, a piezoelectric vibrating reed according to a modification of the first embodiment will be described.
FIG. 15 is a plan view of a piezoelectric vibrating reed according to a first modification of the first embodiment, and is a plan view when viewed from the mount surface side.
The piezoelectric vibrating reed 103 shown in FIG. 15 is different from the first embodiment shown in FIG. 5 in that a pair of notches 143 (notches) are formed at the base end of the support arm 134. The detailed description of the parts having the same configuration as the first embodiment shown in FIGS. 5 and 6 will be omitted.

As shown in FIG. 15, in the support arm portion 134, a pair of notches 143 is formed in part of the side surfaces on both sides in the X direction on the proximal end side of each of the mount electrodes 153 and 154. Each notch 143 is formed in a rectangular shape as viewed in the Z direction, and is recessed inward from the side surface of the support arm 134.
According to this configuration, the vibration excited by the vibrating arms 131 and 132 can narrow the route propagating to the supporting arm 134 via the base portion 133, so that the vibrations can be confined to the vibrating arms 131 and 132. . As a result, it is possible to effectively suppress the vibration leakage of the small piezoelectric vibrating piece 103, to suppress the increase in the CI value, and to suppress the deterioration of the quality of the output signal.

  In addition, as shown by a virtual line in FIG. 15, in each notch portion 143, a deformed portion 144 having a tapered surface 144a can be formed. The deformed portion 144 is an etching residue generated in a small gap as in the case of the deformed portions 138 and 139 formed in the stepped portion 137. The partial electrode 155a of the first lead-out electrode 155 and the partial electrode 152a of the second excitation electrode 152 can be divided by the tapered surface 144a of the deformed portion 144.

Second Embodiment Piezoelectric Vibrating Piece
Next, the piezoelectric vibrating reed of the second embodiment will be described.
FIG. 16 is a plan view of the piezoelectric vibrating reed according to the second embodiment, and is a plan view when viewed from the mount surface side. FIG. 17 is a plan view of the piezoelectric vibrating reed according to the second embodiment, as viewed from the side opposite to the mounting surface.

  In the piezoelectric vibrating reed 3 shown in FIGS. 5 and 6, the support arm 34 is disposed between the pair of vibrating arms 31 and 32. On the other hand, the piezoelectric vibrating reed 203 shown in FIGS. 16 and 17 is different in that the support arm 234 is disposed to the side of the pair of vibrating arms 231 and 232.

As shown in FIG. 16, the base portion 233 connects the proximal ends of the pair of vibrating arms 231 and 232 and also connects the proximal end of the support arm 234 at the end on the −X side.
The support arm 234 has a narrow portion 235 extending along the Y direction, and a wide portion 236 extending from the end on the + Y side of the narrow portion 235 toward the + Y side. The support arm 234 has a pair of step parts 237 between the narrow part 235 and the wide part 236, like the support arm 34 in the piezoelectric vibrating reed 3 of the first embodiment shown in FIG. . Of the pair of stepped portions 237, the stepped portion 237 on the + X side has a first deformed portion 238 provided with a tapered surface 238a. Of the pair of step portions 237, the step portion 237 on the −X side has a second deformed portion 239 having a tapered surface 239a.

  The first mount electrode 253 and the second mount electrode 254 are provided on the mount surface 234 a of the support arm 234. The first mount electrode 253 is formed on the wide portion 236 of the support arm 234, and is disposed at a position not overlapping the deformed portions 238 and 239 in the Y direction. The second mount electrode 254 is formed on the narrow portion 235 of the support arm 234, and is disposed at a position not overlapping the deformed portions 238 and 239 in the Y direction.

  As shown in FIGS. 16 and 17, on the side surface of the support arm 234, a first lead-out electrode 255 and a second lead-out electrode 256 are provided. The first lead-around electrode 255 is formed on the side surface of the wide portion 236. At this time, the first lead-out electrode 255 is formed in the region excluding the tapered surfaces 238 a and 239 a of the side surface on the −Y side of the wide portion 236. The second lead-out electrode 256 is formed on the side surface of the narrow portion 235. At this time, the second lead-out electrode 256 is formed in the region excluding the tapered surfaces 238 a and 239 a of the side surfaces of the narrow portion 235.

  As described above, even if the piezoelectric vibrating piece 203 includes the support arm 234 on the side of the pair of vibrating arms 231 and 232, the support arm 234 includes the tapered surfaces 238a and 239a on the side surface. Thus, the lead-out electrodes 255 and 256 can be divided on the side surface of the support arm 234.

The present invention is not limited to the above-described embodiment described with reference to the drawings, and various modifications can be considered within the technical scope.
For example, the shape of the piezoelectric vibrating reed 3 is not limited to the above shape, and the vibrating arms 31 and 32 may be extended at an angle of about 5 degrees at the maximum with respect to the Y direction. .

  Further, in the present embodiment, the tapered surfaces 38a and 39a are connected to the mounting surface 34a and the anti-mounting surface 34b of the support arm 34, but the present invention is not limited to this. For example, each of the tapered surfaces 38a and 39a may have a step along the Z direction between the mounting surface 34a and the non-mounting surface 34b. At this time, if the height of the step between each of the tapered surfaces 38a and 39a and the mount surface 34a and the non-mount surface 34b is about the same as the thickness of the photoresist film formed in the resist film forming step S7, this step is Can be sufficiently exposed by exposure from the Z direction. Therefore, the lead-out electrodes 55 and 56 can be divided on the distal end side and the proximal end side on the side surface of the support arm 34.

  Further, in the present embodiment, a ceramic package type surface mount type vibrator has been described as the piezoelectric vibrator 1 using the piezoelectric vibrating reed 3, but the base vibrating member 3 is formed of a glass material and a base substrate It is also possible to apply to a glass package type piezoelectric vibrator in which the lid substrate is bonded by anodic bonding.

  In addition, without departing from the spirit of the present invention, it is possible to replace components in the above-described embodiment with known components as appropriate.

  DESCRIPTION OF SYMBOLS 1 ... Piezoelectric vibrator 3, 103, 203 ... Piezoelectric vibrating reed 31, 32, 132, 132, 231, 232 ... Vibrating arm 31b, 32b ... Proximal end of vibrating arm 33, 133, 233 ... Base 34, 134, 234: Support arms 37, 137, 237: Stepped parts 38, 39, 138, 139, 238, 239: Variants 38a, 39a, 138a, 139a, 238a, 239a: Tapered surfaces 53, 153, 253: First mount Electrode (mount electrode) 54, 154, 254 ... second mount electrode (mount electrode) 143 ... notch

Claims (6)

A pair of vibrating arms arranged side by side,
A base connecting the proximal ends of the pair of vibrating arms;
A support arm extending along a longitudinal direction of the pair of vibrating arms and having a proximal end connected to the base;
And a pair of mount electrodes disposed apart from each other in the longitudinal direction on one main surface of the support arm,
The support arms are, in a region corresponding to between the pair of mount electrodes at the side surfaces, have a tapered surface inclined with respect to the thickness direction of the support arm portion,
The mount electrode is formed on the distal end side and the proximal end side of the tapered surface of the side surface of the support arm, and is not formed on the tapered surface.
Piezoelectric vibrating reed characterized in that. The support arm includes a deformed portion protruding from the side surface,
The tapered surface is formed on the deformed portion.
The piezoelectric vibrating reed according to claim 1, wherein A stepped portion is formed on the side surface of the support arm portion,
The deformed portion is formed in the stepped portion,
The piezoelectric vibrating reed according to claim 2, wherein In the support arm portion, a notch is formed in a part of the side surface on the proximal side of the pair of mount electrodes.
The piezoelectric vibrating piece according to any one of claims 1 to 3, characterized in that: The support arm is disposed between the pair of vibrating arms.
The piezoelectric vibrating piece according to any one of claims 1 to 4, characterized in that:   A piezoelectric vibrator comprising the piezoelectric vibrating reed according to any one of claims 1 to 5.

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