JP5018852B2 - Method for manufacturing piezoelectric device - Google Patents

Description

  The present invention relates to a piezoelectric device in which a piezoelectric vibrating piece is housed in a box-shaped package, and an improvement in a method for manufacturing the piezoelectric device.

Piezoelectric devices such as piezoelectric vibrators and piezoelectric oscillators in small information devices such as HDDs (hard disk drives), mobile computers, IC cards, and mobile communication devices such as mobile phones, car phones, and paging systems Is widely used.
A conventional piezoelectric device accommodates, for example, a piezoelectric vibrating piece formed of a piezoelectric material in a package.
The piezoelectric vibrating piece is formed, for example, by etching a quartz wafer into a rectangular shape and providing a driving electrode.

In the piezoelectric device having such a configuration, in order to reliably separate the pair of extraction electrodes formed near both ends in the width direction at the end in the length direction of the rectangular piezoelectric vibrating piece, the piezoelectric vibrating piece is insulated. A technique of applying an adhesive is used (see Patent Document 1).
In addition, a notch is formed between the electrode pads formed on the package side and connected to the piezoelectric vibrating piece to electrically separate the pair of electrode pads for applying drive voltage. There is also a known technique (see Patent Document 2).
Furthermore, a crystal oscillator is known that forms a sealing conductor film when a package containing a piezoelectric vibrating piece is hermetically sealed with a lid (see Patent Document 3).
In this crystal oscillator, a groove is formed outside the pair of electrode pads formed on the surface (inner surface) of the container body (package), and the conductive adhesive flows into the groove, whereby the conductive film for sealing is formed. Touching to prevent short circuit.

JP 2002-208831 A Japanese Patent Laid-Open No. 7-74576 JP 2000-138532 A

However, in the techniques described in these patent documents, even if the short circuit between the electrode pads formed on the package and the short circuit between the extraction electrodes of the piezoelectric vibrating piece can be prevented, Short circuit cannot be prevented.
FIG. 9 shows, for example, a rectangular or strip-shaped piezoelectric vibrating piece 1 called an AT-cut vibrating piece, and an excitation electrode 2 is formed on the main surface thereof. A driving voltage is applied to the excitation electrode 2 through one extraction electrode 3 connected thereto. The other extraction electrode 4 is connected to an excitation electrode (not shown) formed on the back surface.

Thus, the piezoelectric vibrating reed 1 is bonded to the pair of electrode pads 5 and 6 provided on the inner bottom portion of the package, whereby a drive voltage is applied from the electrode pads 5 and 6 to the extraction electrodes 3 and 4. Thus, an electric field is formed inside the piezoelectric material so as to excite the thickness shear vibration via the excitation electrodes connected to each other.
In this case, a conductive adhesive (not shown) is applied to the electrode pad 5, the extraction electrode 3 of the piezoelectric vibrating piece 1 is placed, and the conductive adhesive is also applied to the electrode pad 6 in the same manner. 1 electrode pad 4 is mounted and bonded by heating and curing.

However, when the conductive adhesive applied to the electrode pad 6 flows toward the excitation electrode 2 of the piezoelectric vibrating reed 1, a short circuit occurs as shown by reference symbol A, and oscillation does not occur.
In particular, recently, the piezoelectric vibrating reed 1 has the illustrated dimensions, for example, an X dimension of 1.5 mm, a Z dimension of 1.0 mm, and a Y dimension (thickness t) of about 60 μm. When manufactured, a slight flow of conductive adhesive can cause a short circuit.
On the other hand, since the conductive adhesive obtains the required bonding strength of the piezoelectric vibrating reed 1 depending on the application amount, it is difficult to extremely reduce the application amount in fear of a short circuit.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a piezoelectric device capable of obtaining a sufficient bonding strength of a piezoelectric vibrating piece without causing a short circuit, and a manufacturing method thereof. To do.

  In the present invention, at least a pair of electrode pads are formed on the inner bottom surface of the package, and the corresponding extraction electrode of the piezoelectric vibrating piece is a conductive adhesive with respect to the pair of electrode pads. In the piezoelectric device joined by the piezoelectric device, the piezoelectric vibrating reed is formed by a piezoelectric material so as to be a plate-like body having a rectangular or square outer shape, and the excitation electrode formed on both the front and back surfaces, and the plate A pair of extraction electrodes formed at one end of the body and spaced apart from each other, one of which is connected to one of the front and back excitation electrodes, and the piezoelectric of the pair of extraction electrodes Before the surface of the vibrating piece facing the inner bottom surface, the lead electrode that is not connected to the excitation electrode formed on the facing surface is formed on the inner bottom surface of the package. One electrode pad of the pair of electrode pads and an extraction electrode connected to the excitation electrode formed on the facing surface are connected to the other electrode pad of the pair of electrode pads, respectively. The one electrode pad is achieved by a piezoelectric device formed smaller than the other electrode pad.

According to the above configuration, on the surface facing the inner bottom surface of the package of the piezoelectric vibrating piece, the electrode pad (one electrode pad) to which the lead electrode not connected to the excitation electrode formed on the facing surface is joined Is smaller than the other electrode pad. For this reason, since the one electrode pad is small, the application amount of the conductive adhesive is small, so that it is difficult to flow to the excitation electrode side during bonding, and there is no possibility of coming into contact with the excitation electrode. There is no worry. Moreover, since the other electrode pad is larger than the one electrode pad, the amount of the conductive adhesive applied thereto is large. Therefore, sufficient bonding strength can be obtained on the other electrode pad side, and if the conductive adhesive flows to the excitation electrode side and touches the excitation electrode, the extraction electrode is originally the excitation electrode. There is no worry of a short circuit.
Thus, a piezoelectric device capable of obtaining a sufficient bonding strength of the piezoelectric vibrating piece without causing a short circuit can be obtained.

According to another aspect of the present invention, a groove for preventing the conductive adhesive from flowing is formed at least on an outer edge of the one electrode pad at a region facing the inside of the package.
According to the above configuration, on the surface facing the inner bottom surface of the package of the piezoelectric vibrating piece, the electrode pad (one electrode pad) to which the lead electrode not connected to the excitation electrode formed on the facing surface is joined Is formed with a groove in a region facing the inside of the package at least on the outer edge thereof. For this reason, even if a conductive adhesive flows toward the excitation electrode at the time of joining, since it enters into the groove, the conductive adhesive and the excitation electrode are prevented from contacting each other, and a short circuit is effectively avoided.

In another aspect, the upper surface of the one electrode pad is lower than the upper surface of the other electrode pad.
According to the above configuration, on the surface facing the inner bottom surface of the package of the piezoelectric vibrating piece, the electrode pad (one electrode pad) to which the lead electrode not connected to the excitation electrode formed on the facing surface is joined Is lower than the upper surface of the other electrode pad, so that the distance between the corresponding electrode of the piezoelectric vibrating piece is increased. For this reason, it is effective that the conductive adhesive stays on the one electrode pad side at a distance larger than that on the other electrode pad side, and the conductive adhesive flows toward the excitation electrode during bonding. To be prevented. On the other hand, on the other electrode pad side, since the distance between the piezoelectric vibrating piece and the corresponding extraction electrode becomes narrow, the conductive adhesive spreads widely and the bonding area increases.

In another aspect of the invention, the one electrode pad is formed in a recess or a hole provided on the inner bottom surface of the package.
According to the above configuration, on the surface facing the inner bottom surface of the package of the piezoelectric vibrating piece, the electrode pad (one electrode pad) to which the lead electrode not connected to the excitation electrode formed on the facing surface is joined Is formed in a recess or hole provided on the inner bottom surface of the package. For this reason, at the time of joining, it is effectively prevented that the conductive adhesive enters the recesses and holes and flows to the excitation electrode side.

According to another aspect of the invention, the other electrode pad is raised from the inner bottom surface of the package.
According to the above configuration, since the other electrode pad is raised from the surface of the inner bottom surface of the package, also in this case, in the surface facing the inner bottom surface of the package of the piezoelectric vibrating piece, the facing surface Since the electrode pad (one electrode pad) to which the extraction electrode not connected to the excitation electrode formed on the electrode is joined is lower than the upper surface of the other electrode pad, the corresponding extraction of the piezoelectric vibrating piece The distance between the electrodes increases. For this reason, it is effective that the conductive adhesive stays on the one electrode pad side at a distance larger than that on the other electrode pad side, and the conductive adhesive flows toward the excitation electrode during bonding. To be prevented. On the contrary, since the other electrode pad is raised, the distance between the piezoelectric vibrating piece and the corresponding extraction electrode becomes narrow, and the conductive adhesive spreads widely, so that the bonding area becomes large.

  According to another aspect of the present invention, at least a pair of electrode pads is formed on the inner bottom surface of the package, and a corresponding extraction electrode of the piezoelectric vibrating piece is electrically conductive with respect to the pair of electrode pads. In the piezoelectric device bonded by an adhesive, the piezoelectric vibrating piece is formed of a piezoelectric material so as to be a plate-like body having a rectangular or square outer shape, and excitation electrodes respectively formed on the front and back surfaces; At one end of the plate-like body, the plate-like body is formed so as to be spaced apart from each other, and each one includes a pair of extraction electrodes connected to each one of the front and back excitation electrodes, and among the pair of extraction electrodes, On the surface facing the inner bottom surface of the piezoelectric vibrating piece, an extraction electrode that is not connected to the excitation electrode formed on the facing surface is formed on the inner bottom surface of the package. In addition, one electrode pad of the pair of electrode pads and a lead electrode connected to the excitation electrode formed on the facing surface are respectively connected to the other electrode pad of the pair of electrode pads, By chamfering the corners adjacent to each of the excitation electrodes on the front surface or the back surface of the piezoelectric vibrating piece and the extraction electrodes that are not connected on the same surface on the front surface or the back surface, This is achieved by a piezoelectric device having a chamfered portion.

According to the above configuration, when the piezoelectric vibrating piece is bonded to the electrode pad of the package, the conductive adhesive wraps around the space between the one electrode pad side and the chamfered portion of the piezoelectric vibrating piece. Therefore, it is difficult to flow to the excitation electrode side and there is no fear of coming into contact with the excitation electrode.
Moreover, since the other electrode pad does not have a chamfered portion, the conductive adhesive spreads widely and a sufficient bonding strength can be obtained, and if the conductive adhesive flows to the excitation electrode side, Even if touched, the extraction electrode is originally connected to the excitation electrode, so there is no fear of a short circuit.
Thus, a piezoelectric device capable of obtaining a sufficient bonding strength of the piezoelectric vibrating piece without causing a short circuit can be obtained.

  According to another aspect of the invention, the other container is a container having a package having at least a pair of electrode pads on the inner bottom surface, and a plate shape having a rectangular or square outer shape made of a piezoelectric material. Piezoelectric vibrating piece comprising excitation electrodes respectively formed and a pair of lead electrodes formed at one end of the plate-like body so as to be separated from each other and one of which is connected to one of the front and back excitation electrodes And a post-process following the pre-process, an adhesive application process for applying a conductive adhesive to the pair of electrode pads of the package, and the piezoelectric of the pair of lead electrodes. On the surface facing the inner bottom surface of the resonator element, a lead electrode that is not connected to the excitation electrode formed on the facing surface is formed on the inner bottom surface of the package. One electrode pad of the pair of electrode pads and a lead electrode connected to the excitation electrode formed on the facing surface are connected to the other electrode pad of the pair of electrode pads, respectively. A bonding step of placing the piezoelectric vibrating piece on the pair of electrode pads coated with the adhesive to cure the conductive adhesive, and sealing the package with a lid. A sealing step of stopping, and in the adhesive application step, the amount of adhesive applied to the one electrode pad is less than the amount of adhesive applied to the other electrode pad. This is achieved by the manufacturing method.

According to the above configuration, in the adhesive application step, the amount of adhesive applied to the one electrode pad is less than the amount of adhesive applied to the other electrode pad. Then, there is little conductive adhesive and it is hard to flow to the excitation electrode side. For this reason, since there is no possibility that one extraction electrode contacts the excitation electrode, there is no fear of a short circuit.
Moreover, since the other electrode pad has a larger amount of conductive adhesive than the one electrode pad, the conductive adhesive spreads widely and sufficient bonding strength can be obtained. Even if the electrode flows to the excitation electrode side and touches the excitation electrode, there is no fear of a short circuit because the extraction electrode is originally connected to the excitation electrode.
Thus, a piezoelectric device capable of obtaining a sufficient bonding strength of the piezoelectric vibrating piece without causing a short circuit can be obtained.

In another aspect of the invention, in the adhesive application step, a needle jig including a pair of nozzles corresponding to each electrode pad of the pair of electrode pads is used, and among the pair of nozzles of the needle jig, The nozzle diameter of one nozzle that applies the adhesive of the one electrode pad is smaller than the nozzle diameter of the other nozzle that applies the adhesive to the other electrode pad.
According to the said process, the adhesive agent application quantity to said one electrode pad can be reliably made smaller than the adhesive agent application quantity to said other electrode pad.

1 is a schematic plan view of a piezoelectric device according to a first embodiment of the present invention. The AA cut | disconnection end elevation of FIG. FIG. 2 is an enlarged schematic plan view showing a part of the package of the piezoelectric device of FIG. 1. FIG. 10 is a schematic plan view showing a part of the package in an enlarged manner, and shows a first modification. FIG. 8 is a sectional view taken along the line BB in FIG. The figure which shows the principal part of the 2nd Embodiment of this invention. The figure explaining the adhesive agent coating process of embodiment of the manufacturing method of the piezoelectric device of this invention. The figure which shows an example of the adhesive agent application process of FIG. Explanatory drawing for demonstrating the subject of this invention.

1 and 2 show a first embodiment of a piezoelectric device according to the present invention. FIG. 1 is a schematic plan view of a piezoelectric device in which an internal structure is exposed except for a lid, and FIG. FIG. 6 is a schematic end view taken along the line A, and shows a lid disposed.
In these drawings, the piezoelectric device 30 shows an example in which a piezoelectric vibrator is configured, and the piezoelectric device 30 houses a piezoelectric vibrating piece 40 in a package 36.
Specifically, as shown in FIG. 2, the piezoelectric device 30 houses the piezoelectric vibrating piece 40 in a package 36 including a first substrate 34 and a second substrate 35 laminated on the first substrate 34. is doing. The second substrate 35 is superposed on the first substrate 34 except for the material on the inside thereof to form an internal space S, and constitutes a cavity for accommodating the piezoelectric vibrating piece 40 as a whole.

The first substrate 34 constituting the package 36 is an insulating base, and the upper surface thereof is an inner bottom surface 39 of the package 36. In the case of FIG. 1, a pair of electrode pads are formed at the left end portion of the inner bottom surface at a distance from each other in the width direction. This pair of electrode pads is one electrode pad 32 and the other electrode pad 33.
The pair of electrode pads are connected to mounting terminals 38 and 38 exposed on the bottom surface of the package 36 by a conductive pattern (not shown).
A lid 37 made of a metal such as ceramic, glass or Kovar is joined to the package 36 via a predetermined sealing material. Thereby, the package 36 is hermetically sealed.

As the piezoelectric material forming the piezoelectric vibrating piece 40, for example, a quartz wafer made of quartz is used as a piezoelectric substrate, and this quartz wafer is parallel to the X axis (electrical machine axis) of the quartz and also has a Z axis ( A quartz substrate having a cut surface with respect to the optical axis) is used.
The piezoelectric vibrating piece 40 is formed so that the quartz substrate has a plate-like body having a rectangular or square outer shape, and excitation electrodes 41 and 42 are formed on both the front and back surfaces as the main surface. The piezoelectric vibrating piece 40 is extremely small (for example, width × length × thickness is about 1.5 mm × 1.0 mm × 60 μm).
In addition, the excitation electrodes 41 and 42 are individually connected to the extraction electrodes 43 and 44 which are connection electrodes formed at both ends in the width direction at the end portions in the length direction of the piezoelectric vibrating piece 40. Yes. Each extraction electrode 43, 44 is formed on the back surface of the piezoelectric vibrating piece 40 around the side surface.
That is, the piezoelectric vibrating piece 40 of FIG. 1 has the same form on both sides.

  As shown in FIG. 1, a conductive adhesive 51 is applied to one electrode pad 32, and a conductive adhesive 52 is applied to the other electrode pad 33. The electrodes 43 and 44 are placed, heated, and cured, whereby the piezoelectric vibrating piece 40 is electrically and mechanically joined.

FIG. 3 is a partially enlarged view showing the inside of the package 36 by removing the piezoelectric vibrating piece 40 from FIG. 1.
In the figure, one electrode pad 32 is formed smaller than the other electrode pad 33. That is, as illustrated, the area of one electrode pad 32 is smaller than the area of the other electrode pad 33.
For this reason, the application amount of the conductive adhesive 51 to one electrode pad 32 is smaller than the application amount of the conductive adhesive 52 to the other electrode pad 33.
For this reason, the applied conductive adhesive 51 does not easily flow toward the excitation electrode 42 formed on the back surface of the piezoelectric vibrating piece 40 in FIG. 2, and there is no possibility of coming into contact with the excitation electrode 42. For this reason, there is no fear of a short circuit between the extraction electrode 43 and the excitation electrode 42.

The other electrode pad 33 has a larger area than the one electrode pad 32, and the amount of the conductive adhesive 52 applied thereto is large. For this reason, sufficient bonding strength with respect to the piezoelectric vibrating piece 40 can be obtained on the other electrode pad 33 side.
If the conductive adhesive 52 flows to the excitation electrode 42 side and touches the excitation electrode 42, the extraction electrode 44 is originally connected to the excitation electrode 42, so there is a risk of short circuit. Nor.
Thus, the piezoelectric device 30 capable of obtaining a sufficient bonding strength of the piezoelectric vibrating piece 40 without causing a short circuit can be obtained.

FIG. 4 shows a first modification of the above embodiment, and FIG. 4 is a partially enlarged view showing the inside of the package 36 by removing the piezoelectric vibrating piece 40 from FIG.
In the figure, one electrode pad 32-1 and the other electrode pad 33-1 have the same size.
In this case, a groove for preventing the flow of the conductive adhesive is formed at least on the outer edge of the one electrode pad 32-1 at the region facing the inner side (inward) of the package 36.
In this case, the groove 57 is formed on the inner bottom surface of the package 36 so as to surround one electrode pad 32-1. The groove 57 has a groove portion 55 in a region facing the inside (inward) of the package 36 and a groove portion 56 in a region facing the other electrode pad 33-1.

With such a structure, when the piezoelectric vibrating piece 40 is bonded to the package 36, even if the conductive adhesive 51 flows toward the excitation electrode 42 in FIG. The adhesive 51 and the excitation electrode 42 are prevented from contacting each other, and a short circuit is effectively avoided.
Preferably, as shown in the figure, the groove 57 includes the groove portion 56, so that a short circuit between the pair of electrode pads 32-1 and 33-1 can be prevented.
In the illustrated case, one electrode pad 32-1 and the other electrode pad 33-1 have the same size. However, one electrode pad 32-1 may be smaller or larger than the other electrode pad 33-1. This is because a short circuit can be avoided if the groove 57 prevents the conductive adhesive 51 from flowing out.
A feature of the first modification is that the groove 57 is provided only on the outer edge of one electrode pad 32-1.
That is, the other electrode pad 33-1 is a portion where the extraction electrode 44 is originally connected to the excitation electrode 42 even when the conductive adhesive 52 flows to the excitation electrode 42 side and touches the excitation electrode 42. Therefore, there is no worry of short circuit. Accordingly, it is not necessary to form a groove on the outer edge of the other electrode pad 33-1.
Therefore, the advantage of the first modification is that, for example, a sufficient amount of the conductive adhesives 51 and 52 is applied with one electrode pad 32-1 and the other electrode pad 33-1 having a sufficient area, and bonding strength In addition, the groove portion 55 or the groove 57 is formed only at least on the outer edge of the one electrode pad 32-1, thereby effectively preventing a short circuit between the extraction electrode and the excitation electrode.

FIG. 5 shows a second modification of the above-described embodiment, and shows a cut end surface along the line BB in FIG. 1. However, the configuration of each electrode pad is different from that in FIG.
As shown in the figure, one electrode pad 32-2 is formed in a recess or hole 32a formed in the inner bottom surface 39 of the package, and the other electrode pad 33-2 is formed on the inner bottom surface 39. Is formed. For this reason, the upper surface of one electrode pad 32-2 is made lower than the upper surface of the other electrode pad 33-2.

For this reason, the distance h2 to the piezoelectric vibrating piece 40 on the one electrode pad 32-2 side is larger than the distance h1 to the piezoelectric vibrating piece 40 on the other electrode pad 33-2 side. That is, on the one electrode pad 32-2 side, the amount of the conductive adhesive 51 remaining at a large interval formed in the concave portion or the hole portion 32a is large, and the conductive adhesive 51 is directed toward the excitation electrode 42 in FIG. Is effectively prevented from flowing.
On the other hand, on the other electrode pad 33-2 side, the distance from the piezoelectric vibrating piece 40 becomes narrow, so that the conductive adhesive 52 has one electrode pad 32-- as shown by the lateral dimension W2. It spreads wider than the lateral dimension W1 of the conductive adhesive 51 on the second side, and the joining area is increased.

As a third modification, the other electrode pad 33 described in the embodiment of FIG. 1 may be raised from the surface of the inner bottom surface 39 of the package 36 (not shown).
According to such a configuration, as can be understood from the description of Modification 2, the distance to the piezoelectric vibrating piece 40 is larger on one electrode pad 32 side than on the other electrode pad side. The amount of the conductive adhesive 51 remaining at the interval is large, and the conductive adhesive 51 is effectively prevented from flowing toward the excitation electrode 42 in FIG. 2 during bonding.
On the contrary, since the other electrode pad 33 is raised, the distance from the piezoelectric vibrating piece 40 is narrowed, and the conductive adhesive 52 is spread widely, so that the bonding area is increased.

FIG. 6 is a schematic perspective view showing the configuration of the piezoelectric vibrating piece 40-1 as the main part of the second embodiment of the present invention.
In the second embodiment, the configuration of the package 36 and the lid 37 is the same as that of the first embodiment, and only the configuration of the piezoelectric vibrating piece is different. Therefore, the overlapping description is omitted, and the differences will be mainly described below. Explained.
In this embodiment, the chamfering is performed by chamfering each excitation electrode on the front surface or the back surface of the piezoelectric vibrating piece 40-1 and the corner corner adjacent to the extraction electrode not connected on the same surface on the front surface or the back surface. The point provided with the part is different from the first embodiment.

That is, as shown in the figure, in the piezoelectric vibrating piece 40-1, the corner portion on the surface side of the extraction electrode 43-1 that is not connected to the excitation electrode 41 on the surface side is cut off obliquely, and the chamfered portion 45 is formed. Is formed.
Similarly, the corner portion on the back surface side of the extraction electrode 44-1 not connected to the excitation electrode 42 on the back surface side (see FIG. 2) is cut off obliquely to form a chamfered portion 46.
The present embodiment is configured as described above. When joining together with FIG. 1, that is, when joining the surface side of the piezoelectric vibrating piece 40-1 so as to face the inner bottom surface 39 of the package 36. On the one electrode pad 32 side, the conductive adhesive 51 wraps around and stays in the space formed between the chamfered portion 45 of the piezoelectric vibrating piece 40-1 and therefore, on the excitation electrode 42 (see FIG. 2) side. Since it does not flow easily and there is no possibility of coming into contact with the excitation electrode 42, there is no fear of a short circuit.

In addition, since the other electrode pad 33 does not have a chamfered portion, the conductive adhesive 52 spreads widely and a sufficient bonding strength can be obtained, and the conductive adhesive 52 flows toward the excitation electrode 42. Even if the excitation electrode 42 is touched, there is no fear of a short circuit because the extraction electrode 44-1 is originally connected to the excitation electrode.
In this embodiment, since the chamfered portion 46 is formed, the same effect can be exhibited even if the piezoelectric vibrating piece 40-1 is joined with the front and back reversed.
In this embodiment, one electrode pad 32 and the other electrode pad 33 may be the same size, or may be the same as the configuration of FIG.

(Piezoelectric device manufacturing method)
(pre-process)
The pre-process is a process of separately forming the package 36 that is a container and the piezoelectric vibrating piece 40.
(package)
The first substrate 34 and the second substrate 35 of the package 36 can be formed by laminating and sintering green sheets formed into the shapes shown in FIGS. In this case, the first substrate 34 is a substrate that constitutes the bottom of the package 36, and the second substrate 35 that is stacked on the first substrate 34 has a frame shape by removing the internal material from the above-described green sheet as a plate shape. As shown, the internal space S of FIG. 2 is formed.
On the first substrate 34, for example, after forming a required conductive pattern using a conductive paste such as silver or palladium or a conductive paste such as tungsten metallization, the first and second substrates are sintered. Thereafter, nickel, gold, silver, or the like is sequentially plated to form the electrode pads described above. The conductive pattern for connecting the electrode pad and the mounting terminal 38 may be formed on the surface of a castellation (not shown) used when the package 36 is formed, and the outer surface of the package 36 may be drawn around. Alternatively, the connection may be made by a conductive through hole (not shown) penetrating the first substrate 34.

(Piezoelectric vibrating piece)
A crystal wafer, which is a piezoelectric material for forming the piezoelectric vibrating piece 40, is cut out from a single crystal of crystal so that the crystal axis of the crystal is the electric axis, the Y axis is the mechanical axis, and the optical axis is the Z axis. Will be. In addition, when cutting from a single crystal of quartz, an AT-cut quartz plate cut out at a predetermined angle, for example, 35.15 degrees from the Z axis in the above-described orthogonal coordinate system consisting of the X, Y, and Z axes. Drive electrodes such as excitation electrodes 41 and 42 and extraction electrodes 43 and 44 are formed thereon.
The size of the piezoelectric vibrating piece 40 is extremely small as described above, for example.
As other piezoelectric materials, for example, piezoelectric materials such as lithium tantalate and lithium niobate can be used in addition to quartz. Further, the shape of the piezoelectric chip is not limited to the flat type, and a convex type or a reverse mesa type resonator element can be used.
For example, after forming a nickel or chromium base on the quartz surface, the drive electrode is formed by plating a conductive metal such as gold or silver, and the electrode shape shown in FIGS. 1 and 6 is obtained by a photolithography technique. Is.

(Post-process)
(Adhesive application process)
A conductive adhesive is applied to one electrode pad 32 and the other electrode pad 33 of the package 36 described above.
That is, the conductive adhesive 51 is applied to one electrode pad 32 and the conductive adhesive 52 is applied to the other electrode pad 33.
In this case, one electrode pad 32 and the other electrode pad 33 may be the same size as in FIG. 1, but a small amount of conductive adhesive 51 is applied to one electrode pad 32 and the other electrode pad 33 is applied. For this purpose, the conductive adhesive 52 is applied in a larger amount.
Here, adjustment of the application amount of the conductive adhesive to each electrode pad requires a slight change depending on the size and thickness of the piezoelectric vibrating piece. For example, the conductive adhesive 51 applied to one electrode pad 32 The application amount is preferably 50% to 80% of the application amount of the conductive adhesive 51 to the other electrode pad 33.

In this case, preferably, as shown in FIG. 8, a needle 60 that is a coating jig can be used.
The needle jig 60 includes a small-diameter nozzle 61 having a small nozzle diameter D1 and a large-diameter nozzle 62 having a larger nozzle diameter D2, and a conductive adhesive is applied simultaneously from the small-diameter nozzle 61 and the large-diameter nozzle 62. Can be done. In addition, the gap between the small-diameter nozzle 61 and the large-diameter nozzle 62 is a dedicated jig designed to coincide with the gap between the one electrode pad 32 and the other electrode pad 33.
Therefore, if the small diameter nozzle 61 is aligned on one electrode pad 32 and the large diameter nozzle 62 is aligned on the other electrode pad 33, the conductive adhesive can be discharged from the needle 60 only once, and then the one electrode pad 32 is discharged. An appropriate amount of the conductive adhesive 51 and the conductive adhesive 52 can be simultaneously applied to the other electrode pad 33.

In this way, in the adhesive application step, the adhesive application amount to one electrode pad 32 is smaller than the adhesive application amount to the other electrode pad 33, so on one electrode pad 32 side, The application amount of the conductive adhesive 51 is small and hardly flows to the excitation electrode 42 side in FIG. For this reason, the one extraction electrode 32 has no fear of coming into contact with the excitation electrode 42, so there is no fear of a short circuit.
Moreover, the other electrode pad 33 has a larger amount of application of the conductive adhesive 52 than the one of the electrode pads 32, so that the conductive adhesive 52 spreads widely, and sufficient bonding strength can be obtained. Even if the conductive adhesive 52 flows toward the excitation electrode 42 and touches the excitation electrode 42, there is no fear of a short circuit.

(Joining process)
Next, after applying a conductive adhesive to the one electrode pad 32 and the other electrode pad 33 as indicated by reference numerals 51 and 52, the piezoelectric vibrating piece 40 is placed on the cantilever and heated. As a result, the conductive adhesives 51 and 52 are cured. Thereby, the piezoelectric vibrating piece 40 is bonded to the package 36.
(Sealing process)
Next, for example, the package 36 is accommodated in a predetermined jig or the like, transferred to a vacuum chamber, and the lid 37 is joined to the package 36 by seam welding or the like under vacuum.
Thereby, the package 36 is hermetically sealed.
Thereafter, the piezoelectric device 30 is completed through necessary inspections and the like.

The present invention is not limited to the above-described embodiment. Each configuration of each embodiment can be appropriately combined or omitted, and can be combined with other configurations not shown.
Since the package 36 is a container for a piezoelectric vibrating piece, various configurations are conceivable.
For example, an electrode pad may be formed on a flat insulating substrate and a piezoelectric vibrating piece may be bonded, and then a box-shaped cap having a space inside may be bonded airtightly.
The present invention can be used not only for an AT-cut piezoelectric vibrating piece, but also for a so-called convex type piezoelectric vibrating piece, an inverted mesa-shaped piezoelectric vibrating piece, and the like.
In addition, the present invention is applicable to all piezoelectric devices regardless of the names of piezoelectric vibrators, piezoelectric oscillators, etc., as long as they use a package as a box-shaped container and accommodate a piezoelectric vibrating piece inside. can do.

  DESCRIPTION OF SYMBOLS 30 ... Piezoelectric device, 40 ... Piezoelectric vibrating piece, 32 ... One electrode pad, 33 ... Other electrode pad, 36 ... Package, 41, 42 ... Excitation electrode, 51, 52... Conductive adhesive.

Claims (2)

An accommodation container as a package having at least a pair of electrode pads formed on the inner bottom surface, a plate shape having a rectangular or square outer shape made of a piezoelectric material, excitation electrodes respectively formed on both front and back surfaces, and one end of the plate-like body A pre-process for forming piezoelectric vibrating reeds each including a pair of lead electrodes formed separately from each other and one of which is connected to one of the front and back excitation electrodes;
As a subsequent process following the previous process,
An adhesive application step of applying a conductive adhesive to the pair of electrode pads of the package;
Of the pair of extraction electrodes, the extraction electrode that is not connected to the excitation electrode formed on the opposing surface is formed on the inner bottom surface of the package on the surface facing the inner bottom surface of the piezoelectric vibrating piece. In addition, one electrode pad of the pair of electrode pads and a lead electrode connected to the excitation electrode formed on the facing surface are respectively connected to the other electrode pad of the pair of electrode pads, A bonding step of placing the piezoelectric vibrating piece and curing the conductive adhesive on the pair of electrode pads coated with the adhesive so as to be connected;
A sealing step of hermetically sealing the package with a lid,
In the adhesive application step, the amount of adhesive applied to the one electrode pad is made smaller than the amount of adhesive applied to the other electrode pad. In the adhesive application step, a needle jig having a pair of nozzles corresponding to each electrode pad of the pair of electrode pads is used,
Of the pair of nozzles of the needle jig, one nozzle that applies the adhesive of the one electrode pad has a smaller nozzle diameter than the other nozzle that applies the adhesive to the other electrode pad. The method for manufacturing a piezoelectric device according to claim 1.

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