JP2005109886A - Piezoelectric device, manufacturing method thereof, cellular telephone apparatus using the same, and electronic apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric device which can be easily manufactured with high accuracy even if a product is miniaturized, and can remarkably improve productivity, and to provide a manufacturing method thereof, a cellular phone and an electronic apparatus using the piezoelectric device. <P>SOLUTION: In the method of manufacturing a piezoelectric device; a base substrate layer 31-1 constituting a base substrate, an element layer 32-1 constituting a framed piezoelectric vibrating piece, and a lid layer 33-1 constituting a lid, are formed of a material having almost the same thermal expansion coefficient as that of each of the layers. Each of the layers has a size corresponding to the same number of a plurality of products. The base substrate layer, the element layer, and the lid layer are stacked and fixed. After stacking, the layers are cut into sizes of the products. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a piezoelectric device in which a piezoelectric vibrating piece is accommodated in a package, a manufacturing method thereof, and a mobile phone and an electronic apparatus using 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 is produced, for example, as shown in FIG. 13 (see Patent Document 1).
In FIG. 13A, the piezoelectric device 1 has a structure in which a piezoelectric vibrating piece 3 is accommodated in a package 2 and hermetically sealed with a lid 4.
Therefore, first, the package 2, the piezoelectric vibrating piece 3, and the lid 4 are manufactured separately.
The package 2 is formed of a piezoelectric material such as ceramic, forms a space S1 therein, and is provided with a through hole 2b. And the electrode part 2a, the mounting terminal 5, the metal coating | coated part 6, etc. are formed with a conductive pattern. These conductive patterns are formed by applying a conductive paste such as tungsten metallization to a corresponding portion after forming the package 2 and plating after firing.
Further, a sealing material 7 for joining the lid 4 is arranged on the upper end portion of the package 2 so as to form a predetermined sealing margin.

As shown in FIG. 3 (b), the conductive adhesive 8 is applied on the electrode portion 2a of the package 2 baked after molding, and the end of the piezoelectric vibrating piece 3 is placed, and the conductive adhesive 8 is placed. The piezoelectric vibrating reed 3 is joined in a cantilever manner in the internal space S1 of the package 2 by drying and curing. Further, the lid 4 is hermetically sealed with the sealing material 7 in a vacuum.
Next, by heating the package 2, the interior space S1 is degassed through the through hole 2b.

  Finally, the metal sealing material 9 is disposed in the through-hole 2b (for example, the through-hole 2b is opened upward by reversing the direction of the top and bottom of the package 2 shown in the figure, and the ball-shaped metal sealing material 9 is formed from above. The piezoelectric device 1 is completed by irradiating and melting a laser beam or the like to fill the through hole 2b and seal the hole.

JP 2000-106515 A

However, the manufacturing method as shown in FIG. 13 has the following various problems.
First, in the manufacturing method of FIG. 13, since the package 2, the piezoelectric vibrating piece 3, and the lid 4 having individual product sizes are prepared and joined together, the piezoelectric vibrating piece 1 is downsized. As a result, the size of each part is also reduced, and the difficulty of precision work such as joining, molding, and formation of a conductive pattern is increased.
It is difficult to ensure processing accuracy for making the distance between the electrode portions 2a formed in the package 2 very close. Further, with respect to these electrode portions and the like, it was difficult to apply the conductive adhesive 8 so as not to cause a short circuit, the piezoelectric vibrating piece 3 was aligned with an electrode (not shown), and the horizontal posture in the cantilever structure was maintained. Difficulties increase in many respects, such as bonding.

  Specifically, in order to adopt such a manufacturing method, the internal space S1 of the package 2 needs to have a spatial margin in order to perform the above-described joining operation of the piezoelectric vibrating piece 3, and accordingly, is small in size. If the space is hindered or the space is made extremely small, the joining work of the piezoelectric vibrating piece becomes extremely difficult, the degree of completion is lowered, and the occurrence of defects increases.

With respect to this point, there is a similar problem in the method of disposing the sealing material 7 using the upper end portion of the package 2, and in order to obtain sufficient sealing strength and sealing performance, the package 2 There is a limit to reducing the width of the sealing margin in order to reduce the size. Further, the conductive adhesive 8 contains a silver filler and the like, and therefore requires a minimum application area, and the piezoelectric device 1 has reached a limit in work for further miniaturization.
Furthermore, since extremely small individual parts are handled and operations such as joining are performed in units of products, productivity is poor and unsuitable for mass production.

  The present invention has been made in order to solve the above-described problems. A piezoelectric device that can be easily manufactured with high accuracy even if the product is miniaturized, and that can greatly improve productivity, and its manufacture. It is an object of the present invention to provide a method and a mobile phone and an electronic device using a piezoelectric device.

  According to the first aspect of the present invention, there is provided a base substrate layer constituting a base substrate and a piezoelectric vibrating piece with a frame, each layer having a size corresponding to a plurality of products of the same number. An element layer to be configured and a lid layer to constitute a lid are formed of materials having substantially the same thermal expansion coefficient for each layer, and the base substrate layer, the element layer, and the lid layer are laminated and fixed, This is achieved by a method for manufacturing a piezoelectric device that is cut into the size of each product later.

According to the configuration of the first invention, in this manufacturing method, the base substrate layer, the element layer, and the lid layer corresponding to the size of a plurality of products are laminated and fixed. The process of accommodating the piezoelectric vibrating piece and hermetically sealing it with a lid can be performed simultaneously on a plurality of products, rather than being performed in units of individual products as in the prior art. For this reason, productivity can be improved significantly.
Here, in order to laminate and fix the base substrate layer, the element layer, and the lid layer, it is necessary to maintain the fixed state after fixing, and therefore, the thermal expansion coefficients of the respective layers are made to coincide with each other. .
Further, as the element layer, what constitutes a piezoelectric vibrating piece with a frame is used. Therefore, the frame part becomes a part of a container or package that accommodates the piezoelectric vibrating piece, and these parts are a base layer and a lid layer. Therefore, it is unnecessary to perform various operations required for fixing the piezoelectric vibrating piece in a cantilever manner inside the box-shaped package as in the prior art. In other words, avoiding short-circuiting of the electrode part in the package, it is possible to avoid precise and difficult work such as applying a small amount of conductive adhesive or correctly aligning the posture and orientation of the piezoelectric vibrating piece, Very easy. In addition, since it is not necessary to perform the joining operation of the piezoelectric vibrating piece on the inner surface of the package, the accommodation space of the piezoelectric vibrating piece does not need to be increased in consideration of workability, which is advantageous for downsizing.
Thus, it is possible to provide a method of manufacturing a piezoelectric device that can be easily manufactured with high accuracy even if the product is extremely miniaturized, and can greatly improve productivity.

According to a second invention, in the structure of the first invention, the base substrate layer is made of glass ceramic.
According to the structure of 2nd invention, it becomes easy to match | combine a thermal expansion coefficient with the element layer which comprises a piezoelectric vibrating piece by making the said base base layer into a glass ceramic.

A third invention is characterized in that, in the structure of either the first or second invention, the lid layer is a crystal.
According to the configuration of the third invention, when the lid layer is made of quartz, and the piezoelectric vibrating piece is made of quartz, the thermal expansion coefficients of the lid layer and the element layer can be matched.

A fourth invention is characterized in that, in the structure of any one of the first and second inventions, the lid layer is a high expansion glass.
According to the configuration of the fourth aspect of the invention, the lid layer is made of high expansion glass, so that a transparent lid can be formed without using quartz and the thermal expansion coefficient can be matched with other layers.

According to a fifth invention, in any one of the first to fourth inventions, a low-melting glass is used as a bonding material for bonding the base substrate layer, the element layer, and the element layer to the lid layer. It is characterized by that.
According to the structure of 5th invention, the following various advantages are acquired by using low melting glass as a joining material.
First, the low melting point glass is easy to join because the fluidity at the time of melting is lower than that of a brazing material used for conventional joining, such as a metal brazing material. That is, when the fluidity is high, the fluid flows easily in the gap or pressure state of the joint surface, resulting in unevenness. A low melting point glass having a relatively low fluidity is suitable in order to obtain a sufficient bonding strength by uniformly applying to a limited sealing margin. In addition, the filler contained in the low-melting-point glass forms an appropriate gap between the base substrate layer and the element layer, and between the element layer and the lid layer, thereby forming an accommodation state that does not hinder the operation of the piezoelectric vibrating piece. can do. Further, since the low melting point glass can be applied by applying a screen printing method, it is advantageous in accurately applying the low melting point glass to the entire determined region when bonding each layer corresponding to a plurality of products. In addition, low melting point glass can be applied to a relatively wide area by applying low melting point glass to a relatively wide area of each layer, leaving a region to be sealed, and providing a dicing area that is removed by cutting. Thus, the work is easy, and then the dicing area is removed, whereby the outer dimensions of the product can be reduced as much as possible.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects, before the base base layer, the element layer, and the lid layer are laminated and fixed, a material that becomes the base base layer is processed. A base substrate forming step for forming a plurality of base substrates, a vibrating piece forming step for processing a piezoelectric material to form a plurality of piezoelectric vibrating pieces, and a material for a lid layer are processed to form a plurality of lids. A lid forming step that is performed in separate steps, a base substrate layer that includes the plurality of base substrates, the element layer that includes the plurality of piezoelectric vibrating pieces, and the lid that includes the plurality of lids. A bonding step of laminating and fixing layers, and a post-process that includes the bonding step, and further cuts into individual product sizes after laminating and bonding the base substrate layer, the element layer, and the lid layer And have In a later step, before performing the cutting, the base substrate layer, via a through hole formed to correspond to the individual products, degassed, characterized in that Anafu stop these through holes.

According to the configuration of the sixth invention, the base substrate layer, the element layer, and the lid layer are laminated and fixed before the base substrate layer is processed to form a plurality of base substrates. A substrate forming step, a vibrating piece forming step of processing a piezoelectric material to form a plurality of piezoelectric vibrating pieces, and a lid forming step of forming a plurality of lids by processing a material to be a lid layer are separated from each other. Since there is a pre-process to be performed in the process, for example, there is no difficulty in performing a process of forming a conductive pattern such as an electrode portion on the base substrate layer or the piezoelectric vibrating piece in the course of assembly, Productivity is high because it can be processed at the same time for each product unit.
In addition, since the degassing and hole sealing can be performed in the post-process before cutting into individual product units after stacking and fixing each layer, these operations can also be performed on a plurality of product units at a time. It is advantageous.

According to a seventh invention, in the structure of the sixth invention, in the base substrate forming step, the base substrate is formed by molding and firing a ceramic material, and necessary conductivity such as electrode portions is formed. In forming the pattern, a conductive paste is applied after baking, and after drying, plating is performed.
According to the configuration of the seventh invention, the conductive pattern is formed by applying the conductive paste before firing of the ceramic material and applying the conductive paste after firing instead of applying the paste after firing, as in the prior art. Since plating is performed after drying, a thin region of the ceramic material does not warp after firing, and can be formed into a precise shape.

In the eighth aspect of the invention, the base body is formed of a material having a coefficient of thermal expansion substantially equal to each other, and has a size corresponding to a plurality of products of the same number. A base substrate layer that constitutes a layer, an element layer that is laminated and fixed on the base substrate layer to constitute a piezoelectric vibrating piece with a frame, and a lid layer that is laminated and fixed on the element layer to constitute a lid. And achieved by a piezoelectric device that is cut to the size of each product after each layer is laminated and secured.
According to the configuration of the eighth invention, this piezoelectric device is formed by laminating and fixing each layer having a size corresponding to a plurality of products, and then cutting into the size of each product. Thus, as described in the first invention, a piezoelectric device that is formed with high accuracy and high quality can be obtained even when it is formed in a small size.

  According to the ninth aspect of the present invention, in the ninth invention, there is provided a mobile phone device using a piezoelectric device in which a piezoelectric vibrating piece is housed in an airtight manner between a base and a base, and each layer has a coefficient of thermal expansion substantially equal to each other. A base substrate layer constituting a base substrate, which is formed of a matched material and has a size corresponding to a plurality of products of the same number, and a piezoelectric vibrating piece with a frame fixedly stacked on the base substrate layer And a lid layer that is laminated and fixed on the element layer, and is cut to the size of each product after the layers are laminated and fixed. This is achieved by a cellular phone device that obtains a clock signal for control by a piezoelectric device.

  Further, in the tenth invention, the above object is an electronic apparatus using a piezoelectric device in which a piezoelectric vibrating piece is hermetically accommodated between a base and a base, and the thermal expansion coefficients of the layers are substantially the same. A base substrate layer constituting a base substrate, each of which has a size corresponding to a plurality of products of the same number, and a piezoelectric vibrating piece with a frame laminated and fixed on the base substrate layer. And a piezoelectric layer that is cut to the size of each product after the layers are stacked and fixed. This is achieved by an electronic device adapted to obtain a clock signal for control by the device.

1 to 3 show an embodiment of the piezoelectric device of the present invention, FIG. 1 is a schematic plan view thereof, FIG. 2 is a schematic cross-sectional view taken along line AA of FIG. 1, and FIG. FIG.
In the figure, the piezoelectric device 30 shows an example in which a piezoelectric vibrator is configured. The piezoelectric device 30 houses a piezoelectric vibrating piece in a package 37.
Specifically, the piezoelectric device 30 includes a base substrate 31, a vibrating piece 32 with a frame laminated on the base substrate 31, and a lid 33 laminated and fixed on the vibrating piece 32 with a frame. Have.

In the piezoelectric device 30, the package 37 contains a piezoelectric vibrating piece in an airtight manner, and includes a base substrate 31, a frame portion of the vibrating piece 32 with a frame, and a lid 33.
The base substrate 31 forms the bottom of the package 37. For example, the base substrate 31 is formed by laminating a first substrate 41 and a second substrate 42, and a through hole 43 is formed in the vicinity of the center. Yes. In this embodiment, the through hole has a first hole 44 formed in the first substrate 41 and a second hole 45 formed in the second substrate 42 and having a smaller diameter than the first hole 44. The first hole 44 and the second hole 45 communicate with each other. The through hole 43 is a stepped hole as shown in the figure, and a conductive pattern (metal covering portion) 43 a is formed in the step portion, and is closed by filling the metal sealing material 46.

As understood with reference to FIGS. 1 and 2, the framed resonator element 32 is integrated with the resonator element main body 39 and the resonator element main body 39 that surrounds the periphery of the resonator element main body in a rectangular frame shape. And a frame portion 36.
As can be understood with reference to FIGS. 1 and 3, the resonator element main body 39 includes a pair of vibrating arms 34 and 35 extending in parallel to the left in the drawing from a base portion 38 integrated with the frame portion 36. ing. As shown in FIG. 3, long grooves 11, 11, 12, 12 extending in the length direction of each vibration are formed on the front and back surfaces (upper and lower surfaces in FIG. 3) of each vibration arm 34, 35. Excitation electrodes 14 and 13 are formed in the long grooves 11, 11, 12 and 12 of the vibrating arms 34 and 35. The excitation electrode 14 and the excitation electrode 13 form a pair and function as different polarities, and efficiently form electrolysis inside the resonator element main body 39. Therefore, as shown in FIG. 3, in each vibrating arm 34, 35, one electrode is in the long groove 11, 11, 12, 12, and the other electrode is on the side surface of each vibrating arm 34, 35. Has been placed.

As shown in FIG. 1, in the framed resonator element 32, the excitation electrode 14 is provided with a conductive pattern 14 a that extends around the left end and extends in the width direction. 13 is routed to the right end through a routing portion 13b along the frame portion, and a conductive pattern 13a extending in the width direction is formed.
As shown in FIG. 2, mounting terminals 47 and 48 are formed on the back surface (bottom surface) of the base substrate 31 at the ends in the length direction. In this connection, as shown in FIG. 1, caster portions 16, 16, 16, 16, which are concave portions of ¼ circle, extend in the thickness direction at the four corners of the package 37. Conductive patterns 16a, 16a, 16a and 16a are formed on these surfaces.
Thus, the excitation electrodes 13 and 14 of the resonator element main body 39 are electrically connected to the mounting terminals 47 and 48 via the conductive patterns 13a, 13b and 14a and the conductive patterns 16a of the castellation portions 16. .

  The lid 33 is fixed on the vibrating piece 32 with a frame and hermetically seals the space in which the vibrating piece main body 39 is accommodated. Here, the base substrate 31, the framed vibration piece 32, and the framed vibration piece 32 and the lid 33 are joined together by sealing materials 49 and 49. In this case, the sealing materials 49, 49 are preferably formed of low melting point glass as will be described later. The low-melting-point glass sealing materials 49 and 49 contain a filler so that the filler functions as a spacer. As shown in FIG. 2, in the internal space S <b> 2 of the package 37, The predetermined gaps G1 and G2 can be formed. Thereby, the vibration piece main body 39 can perform the necessary vibration without hindrance without contacting the lid 33 and the inner surface of the base substrate 31.

  The piezoelectric device 30 according to the present embodiment is configured as described above. By bonding the mounting terminals 47 and 48 to a predetermined mounting substrate (not shown) by soldering or the like, from the mounting substrate side, The supplied drive voltage is applied to the excitation electrodes 13 and 14 of the resonator element main body 39, so that the vibrating arms 34 and 35 can bend and vibrate at a predetermined frequency so as to approach and separate the distal ends of each other. .

(Piezoelectric device manufacturing method)
Next, an embodiment of a method for manufacturing the piezoelectric device 30 will be described.
FIG. 4 is a flowchart showing an example of a method for manufacturing the piezoelectric device 30. In this embodiment, the manufacturing process of the piezoelectric device 30 includes a pre-process and a post-process as shown in FIG.
(pre-process)
The pre-process in the manufacturing method of the piezoelectric device 30 includes a base-base layer forming process shown in ST11 to ST17 in FIG. 4, an element layer forming process for forming a framed resonator element shown in ST21 to ST24, and ST31 to ST31. And a lid layer forming step shown in ST33. The substrate base layer forming step, the element layer forming step, and the lid layer forming step are performed separately. That is, the pre-process is an assembly preparation process, and a plurality of fixings are performed in parallel.

(Base substrate layer forming step)
5A and 5B respectively show a second substrate layer 42-1 and a first substrate layer 41-1 for forming a base substrate layer. These correspond to the second substrate 42 and the first substrate 41 described with reference to FIG. 2, and wafers having a size capable of forming a plurality of substrates at a time are used. In this embodiment, for example, in FIG. 5, a wafer that is sized to be able to form each substrate corresponding to four vertical and five horizontal products is shown, but if a larger number is formed at the same time, The production efficiency is further improved.

  The second substrate layer 42-1 and the first substrate layer 41-1 for forming the base substrate layer are each formed of an insulating material, and ceramic is suitable. In addition, a material that has a thermal expansion coefficient that matches or is very close to that of an element layer and a lid layer, which will be described later, is required as a material. In this embodiment, for example, a glass ceramic green sheet is used. . The green sheet is obtained, for example, by dispersing a ceramic powder in a predetermined solution, forming a kneaded product formed by adding a binder into a sheet-like long tape shape, and cutting it into a predetermined length (ST11).

In this embodiment, for example, a green sheet obtained by mixing glass, forsterite (2MgO.SiO ₂ ), and a binder is used.
Specifically, since glass ceramic uses a quartz Z-plate as an element layer to be described later, it is adapted to its thermal expansion coefficient of 13.8 ppm / once (Celsius). The weight ratio is about 30 percent. As for this glass component, for example, SiO ₂ can be 80 percent, R ₂ O (R is one or more selected from Li and K) can be 12 percent, and P ₂ O ₅ can be 8 percent.

  As shown in FIG. 5, the second substrate layer 42-1 in FIG. 5A has castellations 16-1 at positions where the second holes 45 described in FIG. , 16-1, 16-1, and 16-1. In the first substrate layer 41-1 in (b), the castellations 16-2, 16-2 at the positions corresponding to the first holes 44 described in FIG. 16-2, 16-2, and 16-2 are respectively drilled (ST12).

  Next, as shown in FIG. 5C, the second substrate layer 42-1 and the first substrate layer 41-1 are overlapped. FIG. 5C shows a state viewed from below in the stacked state of FIG. 2, and a stepped portion of the through hole 43 appears. Further, castellations 16-1, 16-1, 16-1, 16-1 on the second substrate layer 42-1 side, and castellations 16-2, 16-2 on the first substrate layer 41-1 side. , 16-2, 16-2 are overlapped to form castellations 16-3, 16-3, 16-3, 16-3 of the base substrate layer 31-1 (ST13).

Subsequently, the base substrate layer 31-1 is fired (ST14), and a conductive paste is applied to necessary portions after firing (ST15). FIG. 5D is a view of the base substrate layer 31-1 after firing as seen from the lower surface side of FIG. 2, and the locations of the mounting terminals 47, 48 and the castellations 16-1, 16-2, 16-3. For example, a copper paste or the like is applied to the portion and the metal covering portion 43a of the step portion of the through hole 43, and after drying, plating is performed in the order of nickel and gold (ST16).
As described above, in this embodiment, the conductive pattern such as the terminal is formed by applying the conductive paste before firing of the ceramic material and applying the conductive paste after firing instead of applying the paste after firing, as in the prior art. Since the plating is performed after drying, the thin region of the ceramic material is not warped after firing and can be formed into a precise shape.

  FIG. 6 is a diagram showing the base substrate layer 31-1 so that the surface opposite to that shown in FIG. 5D can be seen. Next, as a sealing material on the bonding surface side of the base substrate layer 31-1. For example, a low-melting glass paste 49-1 is applied (ST17). In this case, since the low melting point glass can be applied to the end surface on the wide bonding surface side of the base substrate layer 31-1 having a size obtained by combining a plurality of individual products, even if the individual products are extremely small, Since the coating operation can be performed on a wide area, the coating operation is easy.

(Element layer formation process)
As shown in FIG. 7A, an element layer 32-1 is prepared. The element layer 32-1 forms the framed resonator element 32 described with reference to FIGS. 1 and 2, and crystal is used as the piezoelectric material. Besides the crystal, lithium tantalate, lithium niobate, etc. The piezoelectric material can be used. In this embodiment, specifically, a wafer made of a quartz Z plate is used. In this case, the thermal expansion coefficient of the quartz crystal Z plate is 13.8 ppm / once (Celsius) as described above.

  As shown in FIG. 7, the element layer 32-1 includes an outer shape of a number of vibrating piece main bodies 39 corresponding to a plurality of products, long grooves (not illustrated) (long grooves 11 and 12 described in FIG. 1 and FIG. 3), which will be described later. Castellations 16-4, 16-4, 16-4, and 16-4 are formed by wet or dry etching at positions corresponding to the four corners of the product that are the intersections of the cutting lines to be performed (ST21). In this case, one element layer 32-1 can form the number of vibrating pieces 32 with a frame corresponding to the same number of products as the base substrate layer 31-1 described above. The dimensions are consistent with the base substrate layer 31-1.

  FIG. 8 shows the next step, in which an electrode pattern is formed on the element layer 32-1. The illustrated excitation electrodes 13 and 14 and the conductive pattern are as described above, and chromium and gold are placed on the inner surface of the hole of the castellation 16-4 corresponding to the excitation electrode and the conductive pattern. Each film is formed by sputtering, and then an electrode is formed through a photolithography process (ST23). FIG. 8 shows an enlarged portion of the element layer 32-1, in order to show a fine conductive pattern.

  Finally, by contacting the probe to the excitation electrodes 13 and 14 of the element layer 32-1, a driving voltage is applied, and while observing the frequency, for example, a laser beam is applied to the electrode portion near the tip of the vibrating arm, The metal film is evaporated and the frequency is adjusted by the mass reduction method (ST24).

(Lid layer formation process)
FIG. 10 is a schematic plan view showing a lid layer 33-1 for forming the lid 33 described in FIG.
Similarly to the base substrate layer 31-1 and the element layer 32-1, the lid layer 33-1 has a size capable of forming the number of lids 33 corresponding to a plurality of products of the same number by cutting. A glass wafer whose outer dimensions are matched with the base substrate layer 31-1 and the element layer 32-1 is prepared (ST31). That is, the wafer that can be used as the lid layer 33-1 needs to be a transparent material that can transmit laser light irradiated from the outside in frequency adjustment described later, and quartz or glass can be used. In the case of crystal, the same crystal Z plate as the element layer 32-1 is used. In the case of glass, a transparent material that substantially matches the thermal expansion coefficient of the crystal Z plate of 13.8 ppm / once (Celsius) is selected. As such a material, for example, not soda glass or borosilicate glass but high expansion glass is used. That is, by adjusting the component ratio of the high expansion glass, the coefficient of thermal expansion is adapted to the above-mentioned 13.8 ppm / once (Celsius).

Next, as shown in FIG. 10, castellations 16-5, 16-5, 16-5, and 16-5 are provided at positions corresponding to the four corners of the product that will be the intersections of the cutting lines described later with respect to the lid layer 33-1. Are respectively drilled (ST32).
Subsequently, as shown in the drawing, a low melting point glass 49 as a sealing material is applied to the joint surface of the lid 33-1 (ST33). In this case as well, as described with respect to the base substrate layer 31-1, the low-melting glass can be applied to the end surface on the wide bonding surface side of the lid layer 33-1 having a size obtained by combining a plurality of individual products. Therefore, even if the individual products are extremely small, this application work can be performed on a large area, so that the application work is easy.

(Post-process)
(Joining process)
Next, as shown in FIG. 11, when the base substrate layer 31-1, the element layer 32-1, and the lid layer 33-1 are completed in the previous step, the element layer 32-1 is formed on the base substrate layer 31-1. Further, the lid layer 33-1 is placed thereon and stacked and bonded by the sealing material 49 (ST51). After the bonding step by this bonding, the castellation of the base substrate layer 31-1 and the element layer 32- Conductivity can be obtained by applying a conductive paste such as a silver paste to a metal coating portion formed in one castellation using a dispenser or the like and drying it. By doing so, the excitation electrodes 13 and 14 and the mounting terminals 47 and 48 of the resonator element can be made conductive.

  Next, the package complex 37-1 in which the base substrate layer 31-1, the element layer 32-1, and the lid layer 33-1 are stacked and fixed is placed in a vacuum atmosphere by using the through holes 43 described in FIG. To degas the internal space. That is, gas and other base components generated from the sealing material 49 and the like are discharged from the inside through the through hole 43. Subsequently, in a vacuum atmosphere, a metal sealing material (not shown) such as a spherical metal ball is placed on the step portion of each through-hole 43 and melted by irradiation with laser light or the like as shown in FIG. The sealing material 46 is filled. At this time, the metal sealing material 46 is appropriately filled by being wetted with the metal coating portion 43a of the stepped portion, and hermetically sealed with holes (ST53).

.
Next, as shown in FIG. 11, the composite package 37-1 is diced along vertical and horizontal cutting lines that intersect at each castellation 16-6 (ST54).
In this case, a dicing area D2 between the vertical cutting lines VC1 and VC2 and a dicing area D1 between the horizontal cutting lines HC1 and HC2 are provided in advance, and these areas D1 and D2 are used for dicing. Let the blades pass. Thereby, the application | coating area | region of the sealing material 49 required for bonding can be taken comparatively large. In other words, since it is separated after leaving the necessary sealing margin, there is no difficulty in applying the sealing material to the narrow joint end face in each product unit as in the past, and the application of the sealing material Therefore, it is not necessary to enlarge the joining end surface of each product more than necessary. Thereby, the external dimension of a product can be made as small as possible.

  After the cut by ST54, as shown in FIG. 2, for each product, the laser beam B is radiated from the outside to the excitation electrode near the tip of 39 of the internal resonator element main body, and the frequency is adjusted by the mass reduction method ( ST55). Next, necessary inspections are performed on individual products (ST56), and the piezoelectric device 30 is completed.

Thus, according to the manufacturing method of the present embodiment, the base substrate layer 31-1, the element layer 32-1, and the lid layer 33-1 corresponding to the size of a plurality of products are stacked and fixed. Therefore, the step of accommodating the piezoelectric vibrating reed in the base and hermetically sealing it with a lid can be performed simultaneously on a plurality of products, rather than being performed in units of individual products as in the prior art. For this reason, productivity can be improved significantly.
In this case, in order to laminate and fix the base substrate layer 31-1, the element layer 32-1, and the lid layer 33-1, it is necessary to maintain a fixed state after fixing, and therefore, thermal expansion of each layer. The coefficients are matched.

Further, as the element layer 32-1, since a layer constituting a piezoelectric vibrating piece with a frame is used, as shown in FIG. 2, the frame part becomes a part of a package 37 that accommodates the piezoelectric vibrating piece. Since this portion is sandwiched and fixed between the base layer 31 and the lid layer 33, it is necessary to fix the piezoelectric vibrating piece in a cantilever manner inside the box-shaped package as in the prior art. Various operations to be performed are unnecessary. In other words, avoiding short-circuiting of the electrode part in the package, it is possible to avoid precise and difficult work such as applying a small amount of conductive adhesive or correctly aligning the posture and orientation of the piezoelectric vibrating piece, Very easy. In addition, since it is not necessary to perform the joining operation of the piezoelectric vibrating piece on the inner surface of the package, the accommodation space of the piezoelectric vibrating piece does not need to be increased in consideration of workability, which is advantageous for downsizing.
Thus, it is possible to provide a method of manufacturing a piezoelectric device that can be easily manufactured with high accuracy even if the product is extremely miniaturized, and can greatly improve productivity.

FIG. 12 is a diagram showing a schematic configuration of a digital mobile phone device as an example of an electronic apparatus using the piezoelectric device according to the above-described embodiment of the present invention.
In the figure, a microphone 308 for receiving the voice of the sender and a speaker 309 for outputting the received content as a voice output are provided, and further, an integrated circuit or the like as a control unit connected to the modulation and demodulation unit of the transmission / reception signal. The CPU (Central Processing Unit) 301 is provided.
In addition to modulation and demodulation of transmission / reception signals, the CPU 301 includes an information input / output unit 302 including an LCD as an image display unit and operation keys for inputting information, and an information storage unit (memory) 303 including a RAM, a ROM, and the like. Control is to be performed. For this reason, the piezoelectric device 30 or the like is attached to the CPU 301, and its output frequency is used as a clock signal suitable for the control content by a predetermined frequency dividing circuit (not shown) incorporated in the CPU 301. Has been. The piezoelectric device 30 or the like attached to the CPU 301 may not be a single device such as the piezoelectric device 30 but may be an oscillator that combines the piezoelectric device 30 and the like with a predetermined frequency dividing circuit or the like.

  The CPU 301 is further connected to a temperature compensated crystal oscillator (TCXO) 305, and the temperature compensated crystal oscillator 305 is connected to the transmitter 307 and the receiver 306. Thus, even if the basic clock from the CPU 301 fluctuates when the environmental temperature changes, it is corrected by the temperature compensated crystal oscillator 305 and supplied to the transmission unit 307 and the reception unit 306.

  As described above, the piezoelectric device according to the above-described embodiment can be used for an electronic apparatus such as the digital mobile phone device 300 including the control unit. Since it can be manufactured in a very small size with high accuracy, the reliability of the product is improved.

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.
In addition, the present invention can be applied to all piezoelectric devices regardless of the names of piezoelectric vibrators, piezoelectric oscillators, etc., as long as they are covered with a package and accommodate a piezoelectric vibrating piece inside. .

The schematic plan view which shows embodiment of the piezoelectric device of this invention. The AA line schematic sectional drawing of FIG. The CC sectional view taken on the line of FIG. The flowchart which shows embodiment of the manufacturing method of the piezoelectric device of FIG. FIG. 2 is a process chart sequentially illustrating a manufacturing process of a base substrate layer in the method for manufacturing a piezoelectric device of FIG. 1. FIG. 2 is a process diagram illustrating a manufacturing process of a base substrate layer in the method for manufacturing a piezoelectric device of FIG. 1. FIG. 3 is a process chart sequentially illustrating a manufacturing process of an element layer in the piezoelectric device manufacturing method of FIG. 1. FIG. 2 is a process diagram illustrating a manufacturing process of an element layer in the method for manufacturing a piezoelectric device of FIG. 1. FIG. 2 is a process diagram illustrating a manufacturing process of an element layer in the method for manufacturing a piezoelectric device of FIG. 1. FIG. 3 is a process diagram illustrating a manufacturing process of a lid layer in the method for manufacturing the piezoelectric device of FIG. 1. Explanatory drawing which shows the joining process in the manufacturing method of the piezoelectric device of FIG. 1 is a diagram showing a schematic configuration of a digital mobile phone device as an example of an electronic apparatus using a piezoelectric device according to an embodiment of the present invention. FIG. 6 is a schematic cross-sectional view showing an example of a conventional piezoelectric device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 30 ... Piezoelectric device, 31 ... Base base | substrate, 32 ... Vibrating piece with a frame, 33 ... Lid, 34, 35 ... Vibrating arm, 36 ... Frame part, 37 ... Package 39... Vibration piece main body, 31-1... Base substrate layer, 32-1... Element layer, 33-1.

Claims (10)

Each layer has a size corresponding to a plurality of products of the same number, a base substrate layer constituting a base substrate, an element layer constituting a framed piezoelectric vibrating piece, and a lid layer constituting a lid. , Each of these layers is made of a material whose thermal expansion coefficient is almost the same,
Laminating and fixing the base substrate layer, the element layer, and the lid layer;
After the lamination, the piezoelectric device is produced by cutting into the size of each product.   The method for manufacturing a piezoelectric device according to claim 1, wherein the base substrate layer is made of glass ceramic.   The method for manufacturing a piezoelectric device according to claim 1, wherein the lid layer is quartz.   The method for manufacturing a piezoelectric device according to claim 1, wherein the lid layer is a high expansion glass.   5. The piezoelectric device according to claim 1, wherein low melting point glass is used as a bonding material for bonding the base substrate layer, the element layer, and the element layer and the lid layer. Method. Before the base substrate layer, the element layer, and the lid layer are laminated and fixed, a base substrate forming step for forming a plurality of base substrates by processing a material to be the base substrate layer, and a piezoelectric material are processed. A pre-process for forming a plurality of piezoelectric vibrating reeds and a lid forming process for forming a plurality of lids by processing a material to be a lid layer in separate steps;
A bonding step of laminating and fixing the base substrate layer formed of the plurality of base substrates, the element layer formed of the plurality of piezoelectric vibrating pieces, and the lid layer formed of the plurality of lids;
Including the joining step, and further comprising a post-process for cutting the base substrate layer, the element layer, and the lid layer and laminating them into individual product sizes.
In the post-process, before performing the cutting, the base substrate layer is degassed through through holes formed corresponding to individual products, and the through holes are sealed. A method for manufacturing a piezoelectric device according to any one of claims 1 to 5.   In the base substrate forming step, the base substrate is formed by forming and firing a ceramic material, and when forming a necessary conductive pattern such as an electrode portion, a conductive paste is applied after firing and dried. 7. The method of manufacturing a piezoelectric device according to claim 6, wherein plating is performed afterwards. A base substrate layer constituting a base substrate, each layer being formed of a material having substantially the same thermal expansion coefficient and having a size corresponding to a plurality of products of the same number;
An element layer constituting a piezoelectric vibrating piece with a frame laminated and fixed on the base substrate layer;
A lid layer that is laminated and fixed on the element layer to form a lid, and
After each layer is laminated and fixed, the piezoelectric device is cut to the size of each product. A mobile phone device using a piezoelectric device in which a piezoelectric vibrating piece is hermetically accommodated between a base and a base, and each layer is formed of a material having substantially the same thermal expansion coefficient, and each has a plurality of products of the same number A base substrate layer constituting a base substrate, an element layer constituting a piezoelectric vibrating piece with a frame laminated and fixed on the base substrate layer, and laminated and fixed on the element layer And a lid layer constituting a lid, and after each layer is laminated and fixed, a control clock signal is obtained by a piezoelectric device cut to the size of each product. A cellular phone device characterized by the above. An electronic device using a piezoelectric device in which a piezoelectric vibrating piece is hermetically accommodated between a base and a base, and each layer is formed of a material having substantially the same thermal expansion coefficient as each other. A base substrate layer constituting a base substrate, an element layer constituting a piezoelectric vibrating piece with a frame laminated and fixed on the base substrate layer, and a layer fixed on the element layer A lid layer constituting a lid, and after each layer is laminated and fixed, a control clock signal is obtained by a piezoelectric device that is cut to the size of each product. An electronic device.

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