JP6630119B2 - Manufacturing method of piezoelectric vibrating reed and wafer - Google Patents

Description

  The present invention relates to a method for manufacturing a piezoelectric vibrating reed, a piezoelectric vibrating reed, and a piezoelectric vibrator.

  For example, in an electronic device such as a mobile phone or a portable information terminal device, a piezoelectric vibrator using crystal or the like is used as a device used for a time source, a timing source such as a control signal, a reference signal source, and the like. As this type of piezoelectric vibrator, there is known a piezoelectric vibrator in which a piezoelectric vibrating piece is hermetically sealed in a package in which a cavity is formed. In recent years, with the miniaturization of electronic devices, the demand for miniaturization of piezoelectric vibrators and piezoelectric vibrating reeds is increasing more and more.

  For example, as described in Patent Document 1, a plurality of piezoelectric vibrating reeds are manufactured at once using a wafer made of a piezoelectric material. At this time, the piezoelectric vibrating reed is formed in a state where the piezoelectric vibrating reed is connected to the frame part supporting the piezoelectric plate via the connection part. On one main surface of the wafer, a pair of extending electrodes extending from the piezoelectric plate to the frame portion through the connecting portion are formed corresponding to the respective piezoelectric vibrating pieces. The frequency of the piezoelectric vibrating reed is measured by, for example, pressing a probe or the like against the extended electrode on the frame portion. Thereafter, the piezoelectric vibrating reed is cut at the connecting portion to be individualized.

  By the way, the strength of each part of the piezoelectric vibrating piece may be reduced as the size thereof is reduced. For this reason, the piezoelectric vibrating reed may be damaged by the stress acting via the connecting portion at the time of individualization. Therefore, it is desirable that the connecting portion is formed to be narrower so that it can be easily cut.

JP 2009-194630 A

  However, in the prior art, since a pair of extension electrodes are formed side by side on one main surface of the connecting portion, a short circuit between the pair of extension electrodes may occur due to patterning accuracy of the extension electrodes. There is a limit to reducing the width of the connecting portion while preventing it. Therefore, the conventional method for manufacturing a piezoelectric vibrating reed has a problem in that the piezoelectric vibrating reed is prevented from being damaged at the time of individualization while the piezoelectric vibrating reed is downsized.

  Therefore, the present invention provides a method of manufacturing a piezoelectric vibrating reed, which can prevent the piezoelectric vibrating reed from being damaged during individualization, a piezoelectric vibrating reed, and a piezoelectric vibrator.

  A method of manufacturing a piezoelectric vibrating reed according to the present invention includes a piezoelectric vibrating reed having a piezoelectric plate, and a pair of excitation electrodes formed on the piezoelectric plate and vibrating the piezoelectric plate when a predetermined drive voltage is applied. A method of manufacturing a piezoelectric vibrating reed using a wafer made of a piezoelectric material, wherein the wafer is provided with the piezoelectric plate and a frame portion supporting the piezoelectric plate via a connecting portion. An outer shape forming step, patterning an electrode film on the wafer, forming the pair of excitation electrodes on the piezoelectric plate, and extending from the piezoelectric plate to the frame portion through the connecting portion, An electrode forming step of forming a first extension electrode and a second extension electrode electrically connected to the excitation electrodes of the first and second electrodes, respectively, and applying the drive voltage between the first extension electrode and the second extension electrode. Apply the piezoelectric plate A frequency adjusting step of adjusting the frequency of the piezoelectric plate by vibrating, and a singulating step of cutting the connecting portion to singulate the piezoelectric plate, wherein the electrode forming step includes: One extension electrode is formed on one main surface of the wafer at the connection portion, and the second extension electrode is formed on the other main surface of the wafer at the connection portion.

  According to the present invention, the first extension electrode is formed on one main surface of the wafer at the connection portion, and the second extension electrode is formed on the other main surface of the wafer at the connection portion. It is possible to prevent the short-circuit between the first extension electrode and the second extension electrode and to reduce the width of the connecting portion as compared with the related art. Therefore, it is possible to prevent the piezoelectric vibrating reed from being damaged at the time of individualization.

  In the method for manufacturing a piezoelectric vibrating reed, it is preferable that the second extended electrode is routed from the other main surface of the wafer to the one main surface of the wafer in the frame portion.

  According to the present invention, since the second extension electrode is routed from the other main surface to the one main surface in the frame portion, when measuring the frequency of the piezoelectric vibrating reed, the probe or the like of the measuring device is used for the wafer. On the other hand, it can be pressed against the extension electrode from the main surface side. For this reason, it is possible to prevent a troublesome work in the frequency adjustment step as compared with a case where probes or the like are pressed against the extended electrodes from both main surfaces of the wafer.

  In the above-described method for manufacturing a piezoelectric vibrating reed, the second extended electrode extends from the other main surface to the one main surface through a through hole penetrating the frame portion in a thickness direction of the wafer. It is desirable.

  According to the present invention, the second extended electrode can be routed from the other main surface to the one main surface without forming the second extended electrode on the side surface of the frame portion. Thus, when patterning the extension electrode, it is not necessary to pattern the extension electrode on the side surface of the frame portion by performing oblique exposure or the like. Therefore, the extension electrode can be easily patterned.

  In the above-described method for manufacturing a piezoelectric vibrating reed, it is preferable that the first extension electrode and the second extension electrode are formed so as to overlap each other at the connection portion when viewed from a thickness direction of the wafer. .

  According to the present invention, since the first extension electrode and the second extension electrode are formed so as to overlap when viewed from the thickness direction, the width of the connecting portion can be formed smaller in the outer shape forming step. Therefore, the connecting portion is easily cut, and it is possible to more reliably prevent the piezoelectric vibrating reed from being damaged at the time of singulation.

  A piezoelectric vibrating reed of the present invention is formed of a piezoelectric material, a piezoelectric plate including a pair of vibrating arms, and a base connecting the base ends of the pair of vibrating arms, formed on the piezoelectric plate, A pair of excitation electrodes for vibrating the piezoelectric plate when the drive voltage is applied, and a first extension electrode and a second extension electrode electrically connected to the pair of excitation electrodes, respectively. A cut surface formed by a non-crystalline surface of a piezoelectric material is provided on a side surface of the base, the first extension electrode is formed on one main surface of the piezoelectric plate, and the second extension electrode is An electrode is formed on the other main surface of the piezoelectric plate, an edge of the first extended electrode is formed at a connection portion between the one main surface and the cut surface, and an end of the second extended electrode is An edge is formed at a connecting portion between the other main surface and the cut surface.

  According to the present invention, the first extended electrode extends to the cut surface on one main surface, and the second extended electrode extends to the cut surface on the other main surface. In the state (1), in the portion where the cut surface is formed (hereinafter, referred to as “connection portion”), each extension electrode is provided on a different main surface. For this reason, the width of the connection portion can be formed narrower than in the related art while preventing a short circuit between the first extension electrode and the second extension electrode in the connection portion, so that a high damage-free height can be obtained. A high quality piezoelectric vibrating reed can be obtained.

  A piezoelectric vibrator of the present invention includes the above-described piezoelectric vibrating reed, and a package that houses the piezoelectric vibrating reed.

  According to the present invention, since the piezoelectric vibrating reed is provided, a high-quality piezoelectric vibrator can be obtained.

  According to the method of manufacturing a piezoelectric vibrating reed of the present invention, the first extension electrode is formed on one main surface of the wafer at the connection portion, and the second extension electrode is formed on the other main surface of the wafer at the connection portion. Therefore, it is possible to prevent the short-circuit between the first extension electrode and the second extension electrode in the connection portion, and to reduce the width of the connection portion as compared with the related art. Therefore, it is possible to prevent the piezoelectric vibrating reed from being damaged at the time of individualization.

  According to the piezoelectric vibrating reed of the present invention, the first extended electrode extends to the cut surface on one main surface and the second extended electrode extends to the cut surface on the other main surface. Before the singulation, each extension electrode is provided on a different main surface at the connection portion. For this reason, the width of the connection portion can be formed narrower than in the related art while preventing a short circuit between the first extension electrode and the second extension electrode in the connection portion, so that a high damage-free height can be obtained. A high quality piezoelectric vibrating reed can be obtained.

FIG. 1 is an external perspective view of a piezoelectric vibrator according to an embodiment. FIG. 2 is an internal configuration diagram of the piezoelectric vibrator according to the embodiment. FIG. 3 is a sectional view taken along line III-III in FIG. 2. FIG. 2 is an exploded perspective view of the piezoelectric vibrator according to the embodiment. FIG. 3 is a plan view of the piezoelectric vibrating reed according to the embodiment. 5 is a flowchart illustrating a method for manufacturing a piezoelectric vibrating reed according to the embodiment. FIG. 7 is a process diagram for describing the method for manufacturing the piezoelectric vibrating reed according to the embodiment, and is a partial plan view of the wafer. FIG. 7 is a process diagram for describing the method for manufacturing the piezoelectric vibrating reed according to the embodiment, and is a partial plan view of the wafer. FIG. 7 is a process diagram for describing the method for manufacturing the piezoelectric vibrating reed according to the embodiment, and is a partial bottom view of the wafer. FIG. 9 is a process diagram for describing a method of manufacturing a piezoelectric vibrating reed according to a modification of the embodiment, and is a partial plan view of a wafer. It is a process drawing for explaining the manufacturing method of the piezoelectric vibrating reed concerning a modification of an embodiment, and is a partial bottom view of a wafer.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Piezoelectric vibrator)
FIG. 1 is an external perspective view of the piezoelectric vibrator according to the embodiment. FIG. 2 is an internal configuration diagram of the piezoelectric vibrator according to the embodiment. FIG. 3 is a sectional view taken along line III-III in FIG. FIG. 4 is an exploded perspective view of the piezoelectric vibrator according to the embodiment.

As shown in FIGS. 1 to 4, the piezoelectric vibrator 1 of the present embodiment includes a package 2 having a cavity C hermetically sealed therein, and a piezoelectric vibrating reed 3 housed in the cavity C. It is a ceramic package type surface mount type vibrator.
Note that the piezoelectric vibrator 1 is formed in a rectangular parallelepiped shape in plan view, and in the present embodiment, the longitudinal direction of the piezoelectric vibrator 1 is referred to as longitudinal direction L, and the transverse direction is referred to as width direction W in plan view. A direction orthogonal to the longitudinal direction L and the width direction W is referred to as a thickness direction T.

As shown in FIG. 3, the package 2 includes a package body 5 and a sealing plate 6 joined to the package body 5 and forming a cavity C between the package body 5 and the package body 5.
The package body 5 includes a first base substrate 10 and a second base substrate 11 joined together in a state of being superimposed on each other, and a seal ring 12 joined on the second base substrate 11.

  As shown in FIG. 4, at the four corners of the first base substrate 10 and the second base substrate 11, cutouts 15 each having a quarter-arc shape in plan view are provided over the entire base substrates 10 and 11 in the thickness direction. It is formed. The first base substrate 10 and the second base substrate 11 are formed, for example, by stacking two wafer-shaped ceramic substrates and joining them, forming a plurality of through-holes penetrating both ceramic substrates, and then forming each through-hole. It is manufactured by cutting both ceramic substrates in a lattice shape while using the holes as a reference. At this time, the through hole is divided into four parts to form the cutout part 15.

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

As shown in FIG. 3, the upper surface of the first base substrate 10 corresponds to the bottom surface of the cavity C.
The second base substrate 11 is overlaid on the first base substrate 10 and is bonded to the first base substrate 10 by sintering or the like. That is, the second base substrate 11 is integrated with the first base substrate 10.

  As shown in FIG. 4, the second base substrate 11 has a through portion 11a. The penetrating portion 11a is formed in a rectangular shape in plan view with four rounded corners. The inner surface of the through portion 11a forms a part of the side wall of the cavity C (see FIG. 3). Mounting portions 14A and 14B protruding inward are provided on the inner surfaces on both sides in the width direction W of the through portion 11a. The mounting portions 14A and 14B are formed substantially at the center in the longitudinal direction L of the through portion 11a.

  The seal ring 12 is a conductive frame member that is slightly smaller than the outer shape of the first base substrate 10 and the second base substrate 11, and is joined to the upper surface of the second base substrate 11. Specifically, the seal ring 12 is bonded onto the second base substrate 11 by baking with a brazing material such as silver brazing or a solder material, or is formed on the second base substrate 11 (for example, electrolytic plating or electroless plating). In addition to plating, they are joined by welding to a metal joining layer that has been deposited (by vapor deposition, sputtering, or the like).

Examples of the material of the seal ring 12 include a nickel-based alloy and the like, and specifically, it may be selected from Kovar, Elinvar, Invar, 42-alloy and the like. In particular, as the material of the seal ring 12, it is preferable to select a material having a thermal expansion coefficient close to that of the first base substrate 10 and the second base substrate 11 made of ceramics. 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 thermal expansion coefficient of the seal ring 12 is 5.2 × 10 ^−. It is preferable to use ⁶ / ° C. Kovar or a 42-alloy having a thermal expansion coefficient of 4.5 to 6.5 × 10 ⁻⁶ / ° C.

  As shown in FIG. 3, the sealing plate 6 is a conductive substrate overlaid on the seal ring 12, and is hermetically bonded to the package body 5 by bonding to the seal ring 12. The space defined by the sealing plate 6, the seal ring 12, the through portion 11a of the second base substrate 11, and the upper surface of the first base substrate 10 functions as a cavity C that is hermetically sealed.

  Examples of the welding method of the sealing plate 6 include seam welding by contacting a roller electrode, laser welding, ultrasonic welding, and the like. In addition, in order to make the welding between the sealing plate 6 and the seal ring 12 more reliable, a bonding layer of nickel, gold, or the like that is familiar to each other is formed on at least the lower surface of the sealing plate 6 and the upper surface of the seal ring 12. Preferably, it is formed.

  As shown in FIG. 4, a pair of electrode pads 20A and 20B, which are connection electrodes with the piezoelectric vibrating reed 3, are formed on the upper surfaces of the mounting portions 14A and 14B of the second base substrate 11. 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 L. The electrode pads 20A and 20B and the external electrodes 21A and 21B are a single-layer film made of a single metal formed by, for example, vapor deposition or sputtering, or a stacked film in which different metals are stacked. Each is conducting.

(Piezoelectric vibrating reed)
FIG. 5 is a plan view of the piezoelectric vibrating reed according to the embodiment.
As shown in FIG. 5, the piezoelectric vibrating reed 3 mainly includes a piezoelectric plate 30 and electrodes 41 to 48 formed on the piezoelectric plate 30. Note that the longitudinal direction L, the width direction W, and the thickness direction T of the piezoelectric vibrator 1 coincide with the longitudinal direction, the width direction, and the thickness direction of the piezoelectric vibrating piece 3. Accordingly, in the following description, the same reference numerals as those in the longitudinal direction L, the width direction W, and the thickness direction T of the piezoelectric vibrator 1 will be used in each of the longitudinal direction, the width direction, and the thickness direction of the piezoelectric vibrating reed 3. The description will be made with reference to FIG.

  The piezoelectric plate 30 is made of a piezoelectric material such as quartz, lithium tantalate, lithium niobate, or the like. The piezoelectric plate 30 includes a pair of vibrating arms (a first vibrating arm 31 and a second vibrating arm 32), a base 35, and a pair of supporting arms (a first supporting arm 33 and a second supporting arm 34). ). The piezoelectric plate 30 is formed such that the shape in a plan view when viewed from the thickness direction T is substantially symmetric with respect to a center axis O along the longitudinal direction L. In the present embodiment, a description will be given using quartz as an example of a piezoelectric material forming the piezoelectric plate 30.

  The vibrating arms 31 and 32 extend in the longitudinal direction L and are arranged in parallel in the width direction W. Each of the vibrating arms 31 and 32 vibrates with a base end as a fixed end and a distal end as a free end. Each of the vibrating arms 31 and 32 has main bodies 31A and 32A located at the base end and weights 31B and 32B located at the tip.

  The main bodies 31A, 32A of the respective vibrating arms 31, 32 extend from the base ends of the respective vibrating arms 31, 32 along the longitudinal direction L. Grooves 37 are formed in the main bodies 31A and 32A. The groove portion 37 is recessed in the thickness direction T and extends along the longitudinal direction L on both main surfaces of the main body portions 31A and 32A. The groove 37 is formed from the base end of each of the vibrating arms 31 and 32 to the tip of the main body 31A and 32A.

Two excitation electrodes (a first excitation electrode 41 and a second excitation electrode 42) are provided on the outer surfaces of the main bodies 31A and 32A of the respective vibrating arms 31 and 32. Each of the excitation electrodes 41 and 42 vibrates each of the vibrating arms 31 and 32 in the width direction W when a predetermined drive voltage is applied. Each of the excitation electrodes 41 and 42 is patterned while being electrically insulated from each other.
Specifically, the first excitation electrode 41 is mainly formed on the groove 37 of the first vibrating arm 31 and on both side surfaces of the second vibrating arm 32. The second excitation electrodes 42 are mainly formed on both sides of the first vibrating arm 31 and on the groove 37 of the second vibrating arm 32.

  The weights 31B, 32B of the respective vibrating arms 31, 32 extend along the longitudinal direction L from the tips of the main bodies 31A, 32A, respectively. Each of the weights 31B and 32B has a rectangular shape in plan view, and has a width in the width direction W larger than that of the main bodies 31A and 32A. As a result, the mass of the tip of each of the vibrating arms 31 and 32 and the moment of inertia at the time of vibration can be increased. Can be shortened.

  A weight metal film 50 is formed on the main surfaces of the weights 31B and 32B. The weight metal film 50 is provided to increase the mass at the tip of each of the vibrating arms 31 and 32 and to suppress an increase in the resonance frequency when the respective vibrating arms 31 and 32 are shortened. In the present embodiment, the weight metal film 50 is formed integrally with each of the excitation electrodes 41 and 42.

The base 35 integrally connects the base ends of the vibrating arms 31 and 32 to each other.
Each of the support arms 33 and 34 is formed in an L shape in plan view, and surrounds the base 35 and each of the vibrating arms 31 and 32 (main bodies 31A and 32A) from the outside in the width direction W. Specifically, after each support arm 33, 34 is protruded from both end surfaces in the width direction W of the base 35 toward the outside in the width direction W, each of the vibrating arms 31, 32 along the longitudinal direction L. And extend in parallel.

  Mount electrodes (a first mount electrode 43 and a second mount electrode 44) are provided on the main surfaces of the support arms 33 and 34, respectively, as mount parts when the piezoelectric vibrating reed 3 is mounted on the package 2. I have. Specifically, the first mount electrode 43 is arranged near the tip of the second support arm 34, and the second mount electrode 44 is arranged near the tip of the first support arm 33.

The two systems of the excitation electrodes 41 and 42 and the two systems of the mount electrodes 43 and 44 are electrically connected to each other by the two systems of the routing electrodes (the first routing electrode 45 and the second routing electrode 46). The first routing electrode 45 is formed on a path from the second support arm portion 34 to each of the vibrating arm portions 31 and 32 via the base 35. The second routing electrode 46 is formed on a path from the first support arm 33 to each of the vibrating arms 31 and 32 via the base 35.
Each of the excitation electrodes 41 and 42, each of the mount electrodes 43 and 44, and each of the routing electrodes 45 and 46 are formed on both main surfaces of the piezoelectric plate 30 so that, for example, their shapes in plan view as viewed in the thickness direction T match. I have.

  A pair of extension electrodes (a first extension electrode 47 and a second extension electrode 48) are provided on the main surface of the base 35. The extension electrodes 47 and 48 are electrically connected to the excitation electrodes 41 and 42, respectively. Specifically, the first extension electrode 47 extends from the first routing electrode 45 toward the central axis O along the width direction W on one main surface of the base 35, and then extends along the central axis O in the longitudinal direction. Along L, the connection portion between the base 35 and each of the vibrating arms 31 and 32 extends toward the opposite side. In the base 35, the edge of the distal end of the first extension electrode 47 is formed at a connection portion 35 a between a cut surface 38, which will be described later, of the side surface of the base 35 and one main surface. The second extension electrode 48 extends from the second routing electrode 46 toward the central axis O along the width direction W on the other main surface of the base 35, and then extends along the central axis O along the longitudinal direction L. The connecting portion between the base 35 and each of the vibrating arms 31 and 32 extends toward the opposite side. In the base 35, the edge of the distal end of the second extension electrode 48 is formed at a connection portion 35b between the cut surface 38 and the other main surface.

  As shown in FIGS. 2 and 3, the piezoelectric vibrating reed 3 configured as described above is housed in the cavity C of the package 2 hermetically sealed. In the piezoelectric vibrating reed 3, the support arms 33 and 34 are electrically and mechanically joined to two electrode pads 20A and 20B provided on the mounting portions 14A and 14B via a conductive adhesive. Thus, the respective vibrating arms 31 and 32 of the piezoelectric vibrating reed 3 are cantilevered via the base 35, the first mount electrode 43 is electrically connected to the electrode pad 20B, and the second mount The electrode 44 is electrically connected to the electrode pad 20A (see FIG. 5).

  It should be noted that a metal bump may be used instead of a conductive adhesive as a conductive bonding material for bonding the support arms 33 and 34 to the electrode pads 20A and 20B. The common feature of the conductive adhesive and the metal bump is that the conductive adhesive has a fluidity at an early stage of bonding and is solidified at a later stage of bonding to exhibit a bonding strength.

  When a predetermined voltage is applied to the external electrodes 21A and 21B, a current flows through the excitation electrodes 41 and 42 shown in FIG. 5, and an electric field is generated between the excitation electrodes 41 and 42. The respective vibrating arms 31 and 32 vibrate at a predetermined resonance frequency, for example, in a direction (width direction W) approaching and separating from each other due to an inverse piezoelectric effect due to an electric field generated between the excitation electrodes 41 and 42. The vibration of each of the vibrating arms 31 and 32 is used as a time source, a timing source of a control signal, a reference signal source, and the like.

(Method of manufacturing piezoelectric vibrating reed)
Next, a method for manufacturing the piezoelectric vibrating reed 3 of the present embodiment will be described. In addition, refer to FIG. 5 for the reference numerals of the respective components in the following description.
FIG. 6 is a flowchart illustrating a method for manufacturing a piezoelectric vibrating reed according to the embodiment. 7 to 9 are process diagrams for explaining a method of manufacturing the piezoelectric vibrating reed according to the embodiment. FIGS. 7 and 8 are partial plan views of the wafer viewed from one main surface side. 9 is a partial bottom view of the wafer viewed from the other main surface side. 8 and 9, illustration of the excitation electrodes 41 and 42, the mount electrodes 43 and 44, the routing electrodes 45 and 46, and the weight metal film 50 is omitted.
As shown in FIG. 6, the method for manufacturing the piezoelectric vibrating reed 3 of the present embodiment includes an outer shape forming step S10, an electrode forming step S20, a weight metal film forming step S30, a frequency adjusting step S40, and an individualizing step. S50.

(Outline forming process)
First, the outer shape forming step S10 is performed. As shown in FIG. 7, in the outer shape forming step S <b> 10, a plurality of piezoelectric plates 30 and a frame portion 62 that supports each piezoelectric plate 30 via a connecting portion 61 are formed on the wafer 60.
Specifically, a mask (outer mask) having a shape corresponding to the outer shape of the piezoelectric plate 30, the connecting portion 61, and the frame portion 62 is formed on both surfaces of the wafer 60 by photolithography. Next, the wafer 60 is subjected to wet etching. As a result, the region not masked by the outer shape mask is selectively removed, and the outer shapes of the plurality of piezoelectric plates 30, the connecting portion 61, and the frame portion 62 are formed. At this time, the piezoelectric plates 30 are arranged side by side in the width direction W and are connected to the frame 62 via the connection 61. Further, of the outer surface of the wafer 60, an end face formed by wet etching is a natural crystal face of quartz.
Next, the respective vibrating arms 31 and 32 are etched to form grooves 37 on both main surfaces of the respective vibrating arms 31 and 32.

  Here, the connecting portion 61 connects the frame portion 62 and the edge of the base portion 35 of the piezoelectric plate 30 opposite to the vibrating arm portions 31 and 32 in the longitudinal direction L. The connecting portion 61 extends from the frame portion 62 toward the base 35 of the piezoelectric plate 30 along the longitudinal direction L. The width of the connecting portion 61 in the width direction W gradually decreases from the frame portion 62 toward the base 35 of the piezoelectric plate 30. A boundary portion 61a between the connecting portion 61 and the piezoelectric plate 30 is provided at a central portion of the edge of the base portion 35 in the width direction W. The boundary portion 61a has the narrowest width in the width direction W at the connecting portion 61. The width of the boundary 61a is, for example, about 30 to 50 μm.

(Electrode formation step)
Subsequently, an electrode forming step S20 is performed. In the electrode forming step S20, the electrode film is patterned on the wafer 60 to form the excitation electrodes 41 and 42, the mount electrodes 43 and 44, and the routing electrodes 45 and 46 on the piezoelectric plate 30, and are connected to each piezoelectric plate 30. Each extension electrode 47, 48 extending to the frame part 62 through the part 61 is formed.
Specifically, an electrode film is formed on the outer surface of the wafer 60 by a sputtering method, an evaporation method, or the like. The electrode film is formed of a single layer film of a metal such as gold, a laminated film having a metal such as chromium as a base layer, and a metal such as gold as an upper layer.

Next, a mask (electrode mask) made of a resist material having a shape corresponding to the outer shape of each of the electrodes 41 to 48 is formed on the surface of the electrode film by a photolithography technique.
Next, the electrode film is etched to selectively remove the electrode film in a region not masked by the electrode mask. Thus, the excitation electrodes 41 and 42, the mount electrodes 43 and 44, and the routing electrodes 45 and 46 are formed on the piezoelectric plate 30. As shown in FIGS. 8 and 9, extending electrodes 47 and 48 extending from the respective piezoelectric plates 30 to the frame 62 through the connecting portions 61 are formed.

  Here, as shown in FIGS. 5 and 8, the first extension electrode 47 is provided on one main surface of the wafer 60. Specifically, the first extension electrode 47 extends from the first routing electrode 45 toward the central axis O along the width direction W on one main surface of the base 35, and then extends along the longitudinal direction L. The connecting portion 61a extends to the frame portion 62 through the connecting portion 61. The distal end of the first extension electrode 47 is a rectangular first pad portion 47 a provided on one main surface of the frame portion 62.

As shown in FIGS. 5, 8, and 9, the second extension electrode 48 is provided over both main surfaces of the wafer 60. Specifically, the second extension electrode 48 extends on the other main surface of the base 35 from the second routing electrode 46 toward the center axis O along the width direction W, and then extends along the longitudinal direction L. The connecting portion 61a extends to the frame portion 62 through the connecting portion 61. As shown in FIGS. 8 and 9, the second extension electrode 48 is formed at the connecting portion 61 so as to overlap the first extension electrode 47 when viewed from the thickness direction T. The width dimension of the connection portion 61 between the extension electrodes 47 and 48 is, for example, 10 μm or more.
The second extension electrode 48 extends from the other main surface of the frame 62 to the first main surface through the end surface of the frame 62. The second extension electrode 48 passes on the end face of the frame portion 62 outside the connecting portion 61 in the width direction W. The distal end of the second extension electrode 48 is a rectangular second pad portion 48 a provided on one main surface of the frame portion 62.

  As shown in FIG. 8, the pad portions 47a and 48a are provided corresponding to the respective piezoelectric plates 30, and are provided alternately in the width direction W. The position of each of the pad portions 47a and 48a is not particularly limited, and may be provided at a position overlapping the piezoelectric plate 30 in the width direction W, or may correspond between the adjacent piezoelectric plates 30 in the width direction W. It may be provided at a position.

(Weight metal film forming process)
Subsequently, a weight metal film forming step S30 is performed. In the weight metal film forming step S30, a weight metal film 50 for frequency adjustment is formed on the surfaces of the weights 31B and 32B of the respective vibrating arms 31 and 32. The weight metal film 50 can be formed, for example, by vapor deposition or the like. The weight metal film 50 may be formed simultaneously with each of the electrodes 41 to 48 in the electrode forming step S20.

(Frequency adjustment process)
Subsequently, a frequency adjustment step S40 is performed. In the frequency adjusting step S40, a predetermined driving voltage is applied between the extending electrodes 47 and 48 to vibrate the respective vibrating arms 31 and 32 of the piezoelectric plate 30, thereby causing the piezoelectric vibrating piece 3 (piezoelectric plate 30) Adjust the frequency.
Specifically, a probe or the like of a measuring instrument for applying a driving voltage to each of the pad portions 47a and 48a on the frame portion 62 is pressed. In this state, a predetermined drive voltage is applied between the excitation electrodes 41 and 42 via the extension electrodes 47 and 48, and the vibration arms 31 and 32 are vibrated. The weight metal film 50 on each of the vibrating arms 31 and 32 is partially removed according to a difference between the frequency measured at this time and a predetermined target frequency of the piezoelectric vibrating reed 3. Accordingly, the mass of each of the vibrating arms 31 and 32 changes, so that the frequency of the vibration of each of the vibrating arms 31 and 32 (the frequency of the piezoelectric vibrating piece 3) changes. Therefore, the frequency of the piezoelectric vibrating reed 3 can be made closer to the target frequency.

(Individualization process)
Subsequently, an individualization step S50 is performed. In the singulation step S50, the connecting portion 61 is cut to singulate the piezoelectric plate 30.
Specifically, each connecting portion 61 is cut such that each piezoelectric plate 30 is bent with respect to the frame portion 62. At this time, since the width of the connecting portion 61 is the narrowest at the boundary portion 61a, the connecting portion 61 is cut at the boundary portion 61a. As a result, as shown in FIG. 5, of the end surface (side surface) of the base 35 of the piezoelectric plate 30, a portion corresponding to the boundary portion 61 a is formed by a surface (amorphous surface) having a structure different from the natural crystal surface of quartz. The cut surface 38 is formed. The cut surface 38 is an uneven surface having, for example, wavy irregularities. Since the first extension electrode 47 is divided at the boundary 61a, an edge of the first extension electrode 47 is formed at a connection portion 35a between the cut surface 38 and one main surface of the base 35. Further, since the second extension electrode 48 is divided at the boundary portion 61a, an edge of the second extension electrode 48 is formed at the connection portion 35b between the cut surface 38 and the other main surface of the base 35. .
As described above, a plurality of piezoelectric vibrating reeds 3 can be manufactured at one time from one wafer 60.

Thus, in the piezoelectric vibrating reed 3 of the present embodiment, the first extension electrode 47 extends to the cut surface 38 on one main surface, and the second extension electrode 48 extends to the cut surface 38 on the other main surface. Therefore, in the state before the piezoelectric vibrating reed 3 is divided into individual pieces, the extension electrodes 47 and 48 are provided on the different main surfaces in the connecting portion 61.
Further, according to the method of manufacturing the piezoelectric vibrating reed 3 of the present embodiment, the first extension electrode 47 is formed on one main surface of the wafer 60 at the connection portion 61, and the second extension electrode 48 is formed at the connection portion 61. It is formed on the other main surface of wafer 60. For this reason, it is possible to prevent the short-circuit between the first extension electrode 47 and the second extension electrode 48 in the connecting portion 61 and to narrow the width of the boundary portion 61a of the connecting portion 61 as compared with the related art. . Therefore, the piezoelectric vibrating reed 3 can be prevented from being damaged at the time of singulation, and the high quality piezoelectric vibrating reed 3 without damage at the time of singulation can be obtained.

  Furthermore, since the second extension electrode 48 is routed from the other main surface to the one main surface in the frame portion 62, when measuring the frequency of the piezoelectric vibrating reed 3, the probe or the like of the measuring device is On the other hand, it can be pressed against each pad portion 47a, 48a from the main surface side. Therefore, it is possible to prevent a troublesome work in the frequency adjustment step S40 as compared with a case where the probe or the like is pressed from both main surfaces of the wafer.

  In addition, since the extension electrodes 47 and 48 are formed so as to overlap when viewed from the thickness direction T, the width of the connecting portion 61 can be made smaller in the outer shape forming step S10. Therefore, the connecting portion 61 is easily cut, and it is possible to more reliably prevent the piezoelectric vibrating reed 3 from being damaged at the time of singulation.

  Further, according to the present embodiment, since the piezoelectric vibrating reed 3 is provided, the high quality piezoelectric vibrator 1 can be obtained.

In the above-described embodiment, the second extension electrode 48 is routed from the other main surface of the frame portion 62 to the one main surface through the end surface of the frame portion 62, but is not limited thereto.
10 and 11 are process diagrams for explaining a method of manufacturing a piezoelectric vibrating reed according to a modification of the embodiment. FIG. 10 is a view of the wafer before the singulation process as viewed from one main surface side. FIG. 11 is a partial bottom view of the wafer before the singulation process as viewed from the other main surface side. 10 and 11, illustration of the excitation electrodes 41 and 42, the mount electrodes 43 and 44, the routing electrodes 45 and 46, and the weight metal film 50 is omitted.

  As shown in FIGS. 10 and 11, a through hole 63 is formed in the frame portion 62 so as to penetrate in the thickness direction T. The through hole 63 is formed outside the region where the first extension electrode 47 is formed. In the present embodiment, the through hole 63 is formed in a region where the second pad portion 48a of the second extension electrode 148 is formed.

  As shown in FIG. 11, the second extension electrode 148 extends from above the connection portion 61 to the through hole 63 of the frame portion 62 on the other main surface of the wafer 60. Further, as shown in FIG. 10, the second extension electrode 148 is routed from the other main surface to the one main surface through the inner peripheral surface of the through hole 63.

  According to this configuration, the second extension electrode 148 can be routed from the other main surface to the one main surface without forming the second extension electrode 148 on the end surface (side surface) of the frame portion 62. Accordingly, when patterning the second extension electrode, it is not necessary to pattern the second extension electrode on the end surface of the frame portion 62 by performing oblique exposure or the like. Therefore, the extension electrode can be easily patterned.

Note that 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, in the above-described embodiment, the piezoelectric vibrating reed 3 is a so-called side arm type vibrating reed in which the support arms 33 and 34 are arranged outside the vibrating arms 31 and 32, respectively. However, the present invention is not limited to this. The piezoelectric vibrating reed is, for example, a so-called center arm type vibrating reed in which one supporting arm is disposed between a pair of vibrating arms, or a vibrating reed having no supporting arm. There may be. Further, a configuration in which a groove is not formed in each vibrating arm may be used.

  Further, in the above embodiment, the second extension electrode 48 is routed from the other main surface to the one main surface in the frame portion 62, but is not limited thereto. For example, in the frame portion 62, the second extension electrode 48 is not routed from the other main surface to the one main surface, but is formed only on the other main surface. Further, the second pad portion 48 a is provided on the other main surface of the frame portion 62. Even in this case, it is possible to prevent the short-circuit between the first extension electrode 47 and the second extension electrode 48 in the connection part 61 and to form the boundary part 61a of the connection part 61 narrower than in the related art. it can. Therefore, the piezoelectric vibrating reed 3 can be prevented from being damaged at the time of singulation, and the high quality piezoelectric vibrating reed 3 without damage at the time of singulation can be obtained.

  Further, in the above embodiment, the second extension electrode 48 is formed only on the other main surface of the base 35, but the present invention is not limited to this. The second extension electrode extends from the second routing electrode 46 on one main surface of the base 35, and is also routed from the one main surface to the other main surface on the piezoelectric plate 30, and faces the connecting portion 61. It may extend.

  Further, in the above embodiment, the first extension electrodes 47 and the second extension electrodes 48 formed corresponding to the respective piezoelectric plates 30 are electrically insulated from each other on the frame portion 62. Although it is patterned in a state, it is not limited to this. On the frame part 62, the first extension electrodes formed corresponding to the respective piezoelectric plates 30 or the second extension electrodes may be electrically connected. Accordingly, when separately measuring the frequencies of the plurality of piezoelectric vibrating reeds 3 in the frequency adjusting step, the probe of the measuring device that presses against one of the extension electrodes electrically connected to each other is set to a predetermined predetermined value. Can be maintained in position. For this reason, when measuring the frequencies of the plurality of piezoelectric vibrating reeds 3 separately, it is possible to prevent a troublesome effort as compared with a case where a pair of probes are moved for each measurement, and to measure the frequency efficiently. It becomes possible.

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

  DESCRIPTION OF SYMBOLS 1 ... Piezoelectric vibrator 2 ... Package 3 ... Piezoelectric vibrating piece 30 ... Piezoelectric plate 31 ... First vibrating arm part 32 ... Second vibrating arm part 35 ... Base 38 ... Cutting surface 41 ... First excitation electrode 42 ... Second excitation electrode 47: first extended electrode 48, 148: second extended electrode 60: wafer 61: connecting portion 62: frame portion 63: through hole

Claims (3)

A piezoelectric vibrating reed having a piezoelectric plate and a pair of excitation electrodes formed on the piezoelectric plate and vibrating the piezoelectric plate when a predetermined driving voltage is applied, using a wafer made of a piezoelectric material. A method for manufacturing a piezoelectric vibrating reed to be manufactured,
An outer shape forming step of forming, on the wafer, the piezoelectric plate and a frame portion that supports the piezoelectric plate via a connecting portion,
The electrode film is patterned on the wafer to form the pair of excitation electrodes with respect to the piezoelectric plate, and extends from the piezoelectric plate to the frame portion through the connecting portion, and to the pair of excitation electrodes. An electrode forming step of forming a first extended electrode and a second extended electrode electrically connected to each other,
A frequency adjusting step of adjusting the frequency of the piezoelectric plate by applying the driving voltage between the first extending electrode and the second extending electrode, and vibrating the piezoelectric plate;
Cutting the connecting portion to separate the piezoelectric plate,
With
In the electrode forming step, the first extension electrode is formed on one main surface of the wafer at the connection portion, and the second extension electrode is formed on the other main surface of the wafer at the connection portion . The second extension electrode is routed from the other main surface to the one main surface through a through hole penetrating the frame portion in a thickness direction of the wafer, and the through hole is provided in the second main surface. It is formed at a position closer to the connection part than the center part of the rectangular pad part of the extension electrode,
A method for manufacturing a piezoelectric vibrating piece. The first extension electrode and the second extension electrode are formed at the connection portion so as to overlap when viewed from a thickness direction of the wafer.
The method for manufacturing a piezoelectric vibrating reed according to claim 1, wherein: A pair of vibrating arms formed of a piezoelectric material, and a piezoelectric plate including a base connecting the base ends of the pair of vibrating arms,
A pair of excitation electrodes formed on the piezoelectric plate and vibrating the piezoelectric plate when a predetermined drive voltage is applied,
A first extension electrode and a second extension electrode electrically connected to the pair of excitation electrodes, respectively;
The piezoelectric plate, a frame portion that supports the piezoelectric plate via a connecting portion,
  A first pad portion and a second pad portion provided on one main surface of the frame portion and connected to the first extension electrode and the second extension electrode, respectively;
  Has,
  The second extension electrode is routed from the other main surface of the frame portion to the one main surface through a through hole penetrating the frame portion in the thickness direction of the wafer,
  The through hole is formed at a position closer to the connecting portion than a central portion of the second pad portion.
A wafer characterized by the above-mentioned.

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