JP2005151336A - Method for manufacturing piezoelectric device and lid, piezoelectric device, mobile phone unit using piezoelectric device, and electronic equipment using piezoelectric device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a lid and a piezoelectric device by which several lids resistant to breaking can be formed at the same time by realizing a structure allowing a light beam for heating to pass through by properly filling a small opening formed in the metallic robust lids with glass, and to provide a piezoelectric device, a mobile phone, and an electronic apparatus using the piezoelectric device. <P>SOLUTION: The method for manufacturing the lids includes a process of forming a number of through holes 42 corresponding to the number of lids 40 in a metal board 60 of such a size that it can be divided into at least several lids 40; a process of arranging a glass board 62 of the size corresponding to the metal board 60 on the metal board 60; a process of filling the through holes 42 with molten glass material by melting the glass board 62; and a process of cutting the metal board 60 into pieces of the size of the individual lids 40. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a manufacturing method of a piezoelectric device and a lid body in which a piezoelectric vibrating piece is accommodated in a package, a piezoelectric device, and a mobile phone and an electronic apparatus using the piezoelectric device.

Piezoelectric vibrators and oscillators in small information devices such as HDDs (hard disk drives), mobile computers, IC cards, mobile communication devices such as mobile phones, car phones, and paging systems, and gyro sensors Such piezoelectric devices are widely used.
A conventional piezoelectric device is configured, for example, as shown in a schematic sectional view of FIG. 12 (see Patent Document 1).

In the figure, the piezoelectric device 1 has an electrode portion 4 formed in a shallow box-shaped package 2 made of ceramic, and the piezoelectric vibrating piece 3 is fixed to the electrode portion 4 using a conductive adhesive 4a. The package 2 is hermetically sealed by a transparent lid 5 made of glass.
After the lid 5 is sealed, the frequency is adjusted by irradiating the package 2 with laser light from the outside through the lid 5 and evaporating a part of the electrodes formed on the piezoelectric vibrating piece 3. Can be done.

  However, in the piezoelectric device 1 having such a structure, the lid body 5 is made of glass, and the lid body 5 made of a relatively fragile material is exposed to the outside. For this reason, when something collides with the lid 5 made of glass, the lid 5 is cracked or chipped, which affects the sealing state and may impair the vibration performance.

For such a harmful effect, for example, it may be possible to use a lid 6 as shown in FIG. 13 (see Patent Document 2).
FIG. 13A is a schematic sectional view of the lid body 6, and FIG. 13B is a schematic plan view of the lid body 6.
In the figure, the lid 6 is made of a strong material such as a metal that is not easily damaged, and has an opening 8 serving as a window. The opening 8 is filled with a glass 7, and the glass 7 can be used to irradiate laser light from the outside. Accordingly, the lid 6 is joined to the above-described package 2 or the like to prevent the above-described adverse effects.

Thus, in order to obtain a structure in which a part of the lid and the package is made transparent, for example, the following structure is introduced in a semiconductor laser generator (see Patent Document 3). That is, a package for sealing a laser diode chip is formed of a cap-shaped metal, and a light transmission window is formed on the cap-shaped package.
In this case, the manufacturing method is such that an opening is formed in a cap-shaped package, a glass tablet is fitted into the opening, and is melted and joined by heating.

JP 2002-171150 A Shokai 57-43628 JP 63-81995

  However, according to such a technique, there is a limit to the hole diameter of the opening in which the glass tablet can be fitted in the manufacturing process, and it is difficult to make it smaller than 0.5 mm, and in order to greatly reduce the size of the piezoelectric device, This method cannot be used. In addition, it is difficult to position and fit the glass tablet in the small-diameter opening, and it is also difficult to polish the hardened surface after melting the glass tablet.

  The present invention has been made to solve the above-described problems, and is a structure in which a small opening formed in a strong metal lid is appropriately filled with glass so that a heating light beam can be transmitted. And a method of manufacturing a lid and a piezoelectric device that can simultaneously form a plurality of lids that are not easily damaged, and a cellular phone and an electronic apparatus using the piezoelectric device and the piezoelectric device. Objective.

According to the first aspect of the present invention, in the first invention, a step of forming at least a number of through holes corresponding to the number of lids on a metal substrate having a size capable of separating at least a plurality of lids, A step of placing a glass plate having a size corresponding to a metal substrate on the metal substrate, a step of filling the glass material in each through-hole by melting the glass plate, and It is achieved by a method for manufacturing a lid, which includes a step of cutting the metal substrate so as to have a size of the lid.
According to the configuration of the first invention, since the metal substrate capable of separating at least a plurality of lids is processed, a plurality or a large number of lids can be processed at a time, and the processing efficiency is excellent. In addition, the glass as a light transmitting material to be filled in the through hole is filled by melting a large glass plate overlaid on the metal substrate, so that the glass tablet is positioned at each opening as in the past, There is no need to fit, and even if the lid is downsized and the through hole is an opening made of a very small through hole, the glass material can be filled without difficulty. The lid formed in this way is made of metal and made of a material that is structurally stronger than glass, so if something collides from the outside, it will not be easily damaged and sealed Impairing performance is effectively prevented. Moreover, since the adjustment window part which filled the glass material in the through-hole is formed in the cover body, the light beam for a heating can be irradiated through this window part.
In this way, a small opening formed in a strong metal lid is properly filled with glass to realize a structure that can transmit the heating light beam, and a plurality of lids that are not easily damaged are formed simultaneously. It is possible to provide a method of manufacturing a lid that can be used.

  According to a second aspect of the present invention, there is provided a method of manufacturing a piezoelectric device in which a piezoelectric vibrating piece is accommodated in a package and hermetically sealed by a lid, the package and the piezoelectric vibrating piece And an individual forming step for separately forming the lid, a step of bonding the piezoelectric vibrating piece to the insulating base constituting the package, and the package being hermetically sealed by the lid A lid sealing step for sealing, and a frequency adjusting step for irradiating a heating light beam to the metal film formed on the piezoelectric vibrating piece from the outside of the package. In the lid forming step, Forming a number of through holes corresponding to the number of the lids on a metal substrate made of a metal material having a thermal expansion coefficient approximate to that of the package, the size being at least capable of separating a plurality of lids; The metal A step of placing a glass plate having a size corresponding to the plate on the metal substrate, a step of filling the glass material in each through-hole by melting the glass plate, and the individual lids Cutting the metal substrate so as to have a body size, and in the frequency adjusting step, the piezoelectric vibration in the package is passed through the glass material filled in the opening of the lid. A method for manufacturing a piezoelectric device, wherein the frequency of the metal film is adjusted by irradiating a part of the metal film with a heating light beam from outside the package to evaporate a part of the metal film.

According to the configuration of the second invention, in the lid forming step, the metal lid is provided with an opening used for frequency adjustment, so even a very thin lid is resistant to external impact and filled with glass. Opening can be provided. For this reason, in the frequency adjustment step after the lid is sealed, the metal film of the piezoelectric vibrating piece in the package can be irradiated with an external heating light beam through the glass that transmits light. Thus, the piezoelectric device that has been frequency-adjusted after lid sealing and has performed precise frequency matching is resistant to external impact because the lid is not made of glass, and is not easily damaged.
In this case, in the lid forming step, a metal substrate capable of separating at least a plurality of lids is processed, so that a plurality or a large number of lids can be processed at a time, and the processing efficiency is excellent. In addition, the glass as a light transmitting material to be filled in the through hole is filled by melting a large glass plate overlaid on the metal substrate, so that the glass tablet is positioned at each opening as in the past, There is no need to fit, and even if the lid is downsized and the through hole is an opening made of a very small through hole, the glass material can be filled without difficulty.

According to a third aspect of the present invention, in the configuration of the second aspect of the invention, in the step of forming the lid, the step of forming the through hole is formed by drilling the through hole from one main surface of the metal substrate by wet etching. It was made to do.
According to the configuration of the third invention, in addition to the operation of the second invention, when wet etching is performed from one side of the substrate, the diameter is gradually reduced along the direction in which the etching proceeds. Through-holes can be formed. And the inner peripheral surface of a through-hole becomes a rough surface. For this reason, while joining area with the glass material with which it fills in a through-hole is enlarged, the anchor effect by a rough surface is exhibited and glass material will be joined reliably.

According to a fourth aspect of the invention, in the configuration of the second or third aspect of the invention, in the lid forming step, the surface of the metal substrate is formed after the through hole is formed and before the glass plate is placed. Etching is made to be a rough surface.
According to the structure of 4th invention, in addition to the effect | action of either 2nd or 3rd invention, before the arrangement | positioning process of the said glass plate, the process of etching the surface of the said metal substrate and making it a rough surface As a result, the bonding strength with the glass material is enhanced even at the periphery of the opening of the through hole.

5th invention WHEREIN: In the structure in any one of 2nd thru | or 4th invention, in the formation process of the said cover body, in the arrangement | positioning process of the said glass plate, the glass plate used is required for filling of molten glass. A glass plate having a thickness greater than the thickness to be used is used, and after the step of filling the through glass with the molten glass material, the surface is mirror-polished to reduce the thickness.
According to the configuration of the fifth invention, in addition to the action of any one of the second to fourth inventions, the glass plate used is thicker than the thickness required for filling the molten glass. A plate is used, and after the step of filling the molten glass material into the through hole, the surface is mirror-polished to reduce the thickness, so the amount of glass material required for filling is insufficient. Can be prepared so that filling does not occur. In addition, by polishing the surface of a large glass plate, extremely small glass materials can be easily polished at the same time as compared with polishing individual glass materials filled in the through holes.

A sixth invention is characterized in that, in the configuration of any one of the second to fifth inventions, the periphery of the through hole has a shape in which small curved surfaces are continuous.
According to the configuration of the sixth invention, in addition to the action of any one of the second to fifth inventions, the bonding area between the through hole and the glass material filled therein is increased, and the bonding strength is increased. Can be improved.

According to a seventh aspect of the present invention, there is provided a piezoelectric device in which a piezoelectric vibrating piece is housed in a package hermetically sealed by a metal lid, and the lid includes at least a plurality of lids. A through-hole corresponding to the number of the lids is formed in a metal substrate having a size capable of separating the lid, and a glass plate having a size corresponding to the metal substrate is overlaid on the metal substrate, This is achieved by a piezoelectric device provided with an adjustment window portion used for frequency adjustment, which is provided by filling a molten glass material into each through-hole by melting a glass plate.
According to the structure of 7th invention, the glass as a light transmissive material with which the through-hole of the cover of the piezoelectric device of this invention is filled is filled by melting a large glass plate on the metal substrate. Therefore, it is not necessary to position and fit a glass tablet in each opening as in the conventional case, and even if the through-hole is an opening made of a very small through-hole, the glass material can be used. Can be filled without difficulty. The lid formed in this way is made of metal and is formed of a material that is structurally stronger than glass. For this reason, this piezoelectric device is not easily damaged when something collides from the outside, and it is effectively prevented that the sealing performance is impaired. Moreover, since the adjustment window part which filled the glass material in the through-hole is formed in the cover body, the light beam for a heating can be irradiated through this window part.

  Furthermore, in the eighth invention, the above object is a mobile phone device using a piezoelectric device in which a piezoelectric vibrating piece is housed in a package hermetically sealed by a metal lid. At least a number of through holes corresponding to the number of the lids are formed in the metal substrate having a size capable of separating at least a plurality of lids, and the glass plate having a size corresponding to the metal substrate is formed on the lid. A piezoelectric device provided with an adjustment window portion used for frequency adjustment provided by filling the glass material melted in each through-hole by overlapping the metal substrate and melting the glass plate, This is achieved by a cellular phone device adapted to obtain a clock signal for control.

  According to a ninth aspect of the present invention, there is provided an electronic apparatus using a piezoelectric device in which a piezoelectric vibrating piece is housed in a package hermetically sealed by a metal lid, wherein the lid However, at least a number of through holes corresponding to the number of the lids are formed in a metal substrate having a size capable of separating at least a plurality of lids, and a glass plate having a size corresponding to the metal substrate is formed on the metal substrate. The piezoelectric device is provided with an adjustment window portion used for frequency adjustment provided by filling the molten glass material in each through hole by melting the glass plate, and for controlling This is achieved by an electronic device that obtains a clock signal of

1 and 2 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. 3 is a piezoelectric device of FIG. 4 is a schematic perspective view of a piezoelectric vibrating piece housed in the package, and FIG. 4 is an end view taken along the line BB of 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 32 in a package 37. As will be described later, the package 37 is formed by, for example, laminating a plurality of substrates formed by molding an aluminum oxide ceramic green sheet as an insulating material, followed by sintering.

  That is, in this embodiment, the package 37 is formed by laminating the first substrate 55 and the second substrate 56, and the total length L1 shown in FIG. 2 is extremely small, for example, about 2.0 mm. As shown in FIG. 2, the package 37 forms a space of the internal space S by removing the material inside the second substrate 56. This internal space S is a housing space for housing the piezoelectric vibrating piece 32. The first substrate 55 corresponds to an insulating base, and the piezoelectric vibrating piece 32 is bonded to the first substrate 55.

For example, nickel plating and gold plating on tungsten metallization are applied to the first substrate 55 as an insulating base that is exposed to the internal space S and constitutes the inner bottom portion in the vicinity of the left end portion of the internal space S of the package 37. The electrode parts 31, 31 formed in (1) are provided.
The electrode portions 31 and 31 are connected to the mounting terminals 48 and 48 shown in FIG. 2, respectively, and supply drive voltage applied from the outside to the piezoelectric vibrating piece 32. Specifically, the mounting terminals 48, 48 and the electrode portions 31, 31 are routed outside the package 37 by metallization, or use tungsten metallization or the like before firing the first substrate 55 and the second substrate 56. It can be formed by connecting with a conductive through hole or the like formed in this way.
A conductive adhesive 47 is applied on each electrode portion 31, and the base portion 51 of the piezoelectric vibrating piece 32 is joined. As the conductive adhesive 47, for example, a binder component using a synthetic resin or the like is mixed with conductive particles such as silver particles, and can perform mechanical joining and electrical connection at the same time. .

The piezoelectric vibrating piece 32 is formed of, for example, quartz, and a piezoelectric material such as lithium tantalate or lithium niobate can be used in addition to quartz. In the case of the present embodiment, the piezoelectric vibrating reed 32 is formed in a small size and has a shape particularly shown in FIG. 3 in order to obtain necessary performance.
That is, the piezoelectric vibrating piece 32 has a base 51 fixed to the package 37 side, and a pair of vibrating arms 35 and 36 that extend parallel to the fork 51 in a diagonally rightward direction with the base 51 as a base end. A so-called tuning fork type piezoelectric vibrating piece having a shape like a tuning fork is used.

  Here, long grooves 33 and 34 extending in the length direction are preferably formed on the main surfaces of the vibrating arms 35 and 36, respectively, and excitation electrodes 38 and 39 are formed in the long grooves. The long grooves are formed on the front and back surfaces, which are the main surfaces of the vibrating arm 35 and the vibrating arm 36, respectively, and as shown in FIG. 4, excitation electrodes 38 and 39 are formed in the long grooves 33 and 34, respectively. The excitation electrodes formed in the long grooves of the vibrating arms are a pair of electrodes separated from each other. As a result, by applying a driving voltage to the excitation electrode, the electric field efficiency inside each vibrating arm can be increased during driving.

  Further, as described above, a lead-out is provided near both ends in the width direction of the end portion (left end portion in FIG. 1) of the base portion 51 of the piezoelectric vibrating piece 32 as an electrode portion for connecting to the electrode portions 31 and 31 of the package 37. Electrodes 38a and 39a are formed. Each extraction electrode 38 a and 39 a is provided on the front and back of the base 51 of the piezoelectric vibrating piece 32 so as to go around the outer edge of the base 51. These lead electrodes 38a and 39a are connected to the above-described excitation electrodes, and can be formed, for example, by sequentially plating chromium (Cr) and gold (Au) on the quartz surface. In addition, at least at the tip region of the surface of the vibrating arms 35 and 36, metal films 53 and 54 for frequency adjustment are formed at the same time when the electrodes are formed by using the same metal as the electrode metal.

As a result, a drive voltage is applied to the excitation electrodes 38 and 39 from the extraction electrodes 38a and 39a, so that an electric field is appropriately formed in each of the vibrating arms 35 and 36. Driven to approach and separate from each other, it vibrates at a predetermined frequency.
The piezoelectric vibrating piece is not limited to the tuning-fork type piezoelectric vibrating piece as shown in the figure, and various piezoelectric vibrating pieces such as an AT cut vibrating piece obtained by cutting a piezoelectric material into a rectangular shape or a convex type vibrating piece may be used. Can do.

A lid 40 is bonded to the opened upper end of the package 37 so as to be sealed.
The lid 40 is formed with a very thin thickness, for example, a thickness of 0.1 mm or less. The material of the lid 40 is made of a strong material that is harder to break than the glass material, and is formed by processing a metal substrate described later. Preferably, a material having a thermal expansion coefficient approximate to that of the package 37 is selected as a material for forming the lid 40. For example, a Kovar alloy that is an alloy of iron, nickel, and cobalt is suitable for satisfying such a condition.

As shown in FIGS. 1 and 2, the lid body 40 is formed with a frequency adjustment window portion (hereinafter referred to as “window portion”) 41. The window 41 is a through-hole 42 that penetrates the lid 40 on the front and back as shown, and preferably has a tapered shape that gradually decreases in diameter toward the outside as shown. .
When the through hole 42 has such a taper shape, the bonding area between the glass and the through hole 42 described later can be increased and the bonding strength can be improved as compared with the case where the through hole 42 is not. The shape of the opening is not limited to a circle, and may be an oval, an ellipse, a polygon, or the like. In particular, it is preferable that the opening of the through hole 42 has a shape with a continuous small curved surface because the area of the inner surface of the through hole 42 can be increased.
And the part in which the window part 41 is formed is provided in the position which opposes the metal film for frequency adjustment of the piezoelectric vibrating reed 32 accommodated in the inside in the state which the cover body 40 sealed the package 37. FIG. In this case, the portion is opposed to the tip region of the vibrating arm 36 and / or 35 of the piezoelectric vibrating piece 32. As shown in FIG. 1, preferably, the through hole 42 is formed at a position where a metal film (described later) of the tip region of each of the vibrating arms 35 and 36 enters the opening, and the opening diameter is also the same as that of the metal film. It is the size to be exposed.
The inner peripheral surface of the through hole 42 is a rough surface 42a. The rough surface 42a is obtained by intentionally roughening the surface roughness of the inner peripheral surface of the through-hole 42, and the friction is larger than that of a flat surface.

  A glass 43 is attached to such a through hole 42. The glass 43 can be variously used as long as it has a property of transmitting a heating light beam such as a laser beam or a halogen beam as a heating light beam used for frequency adjustment described later. In consideration of ease of processing, cost, and the like, it is particularly preferable to select a material having a thermal expansion coefficient approximate to that of the material constituting the lid 40. In this respect, borosilicate glass, Kovar glass, or the like is used as the glass used. In this embodiment, the flange portion 44 having an outer diameter larger than the inner diameter of the through hole 42 is preferably provided at the lower end of the insertion portion 46 inserted into the through hole 42 of the glass 43 as a portion not inserted into the through hole 42. Is provided. The glass 43 is directly bonded to the lid body 40 at the outer periphery and the upward stepped portion 44 a of the flange portion 44.

  When the lid 40 is formed of a metal material such as Kovar, the lid 40 is fixed to the package 37 by a technique such as seam welding. Alternatively, for example, the surface of the lid 40 may be plated with nickel and gold, and the brazing material 37a may be joined using a gold-tin alloy (Au—Sn).

This embodiment is configured as described above, and the lid 40 for sealing the package 37 of the piezoelectric device 30 is formed of a material that is structurally stronger than glass called metal. In the case of collision, it is not easily damaged, and it is effectively prevented that the sealing performance of the package 37 is impaired.
Further, since the lid body 40 is provided with an adjustment window portion 41 formed by attaching a glass 43 to the through hole 42, the metal film formed on the piezoelectric vibrating piece 32 inside the package through the window portion 41. 53 and 54 can be irradiated with a heating light beam such as a laser beam or a halogen beam as indicated by reference numeral LB in FIG. In this case, even if the lid 40 is formed so as to be extremely thin and a step portion cannot be provided inside the through hole 42, the contact surface between the through hole 42 and the glass 43 is Since the rough surface 42a is used, the glass 43 can be directly held by the frictional force by using the rough surface, and the anchor effect can be effectively enhanced and held.

Thus, in the piezoelectric device 30 including the package 37 sealed with the extremely thin lid 40 formed of a strong material for sealing the package 37, the laser light enters the package 37 from the outside of the lid 40. It is possible to realize a structure in which LB or the like can be transmitted and the frequency can be adjusted by the mass reduction method.
Further, as described with reference to FIG. 2, the glass 43 preferably includes a flange portion 44.
For this reason, in addition to the above-described effects, the glass 43 is positioned at the upper stepped portion 44a that is a contact surface of the outer periphery of the insertion portion 46 inserted into the through hole 42 and the peripheral portion of the through hole 42 of the flange portion 44. Therefore, since it joins with respect to the cover body 40, it can be set as a fixed structure with more reliable and high joining strength because a joining area increases.
Moreover, since the flange portion 44 is provided in the lower portion of the glass 43, it does not fit inside the lid body 40 and does not enlarge the outer shape of the piezoelectric device 30, so the size of the surface mounted piezoelectric device 30 in the height direction is large. Can be stored compactly.

FIG. 5 is a schematic sectional view showing a modification of the piezoelectric device of the first embodiment.
Since the piezoelectric device 30-1 in FIG. 5 has the same structure as the piezoelectric device 30 of the first embodiment except for the shape of the glass 43, the same components are denoted by the same reference numerals and redundant description is omitted. Hereinafter, the differences will be mainly described.
In the piezoelectric device 30-1, a flange portion 44-1 is formed at the upper end of the glass 43 attached to the through hole 42 of the lid body 40, and the flange portion 44-1 protrudes outside the lid body 40. . The through hole 42 is formed in a tapered shape that gradually increases in diameter outward from the lid body 40. Therefore, although the dimension in the height direction of the piezoelectric device 30-1 is enlarged by the outward projecting amount, the internal space S of the package 37 is increased correspondingly, and the vibration arm 35 of the piezoelectric vibrating piece 32 is increased accordingly. When the tip portion swings upward, a situation where it abuts on the flange portion can be effectively avoided. Other functions and effects are the same as those of the piezoelectric device 30 of the first embodiment.

(Piezoelectric device manufacturing method)
Next, an embodiment of a method for manufacturing the piezoelectric device 30 (30-1) will be described with reference to the flowchart of FIG.
First, the piezoelectric vibrating piece 32, the lid 40, and the package 37 described with reference to FIGS. 1 to 6 are formed separately.
(Piezoelectric vibrating piece forming process)
The piezoelectric vibrating piece 32 can be manufactured in the same manner as in the prior art by, for example, etching a quartz wafer to form the shape already described and forming the necessary excitation electrode (ST11). Description is omitted. After the electrodes are formed, the drive voltage is applied to roughly adjust the frequency (ST12).
(Package formation process)
The package 37 described with reference to FIG. 1 and FIG. 2 is formed by, for example, dispersing a ceramic powder in a predetermined solution and forming a kneaded product formed by adding a binder into a sheet-like long tape shape. A so-called green sheet obtained by cutting into lengths is prepared.
The green sheet can be commonly used for forming the first substrate 55 and the second substrate 56 described above.

The first substrate 55 and the second substrate 56 are formed so as to be compatible with the above-described structures, and form each electrode portion and conductive pattern. That is, a conductive paste, such as tungsten metallization, is applied to the green sheet to be the first substrate 55 corresponding to the mounting terminals 48, 48 on the back side. Tungsten metallization is applied to the front side corresponding to the electrode portions 31 and 31. Further, through holes are formed as necessary, and a conductive paste is applied to form conductive through holes. The green sheet to be the second substrate 56 is removed of the material so as to correspond to the internal space S.
After the molding, the first and second substrates are laminated, and after firing, nickel and gold are plated on the tungsten metallization. In the case where the sealing material is not provided on the lid side, for example, a gold tin alloy (Au—Sn) 37 a is provided on the upper end of the package 37 as the sealing material. Or when sealing the cover body 40 with a seam ring, the seam ring 37a will be provided.

(Cover forming process)
A case where the lid 40 is formed using a Kovar plate will be described.
As shown in FIG. 7A, a Kovar metal substrate is prepared. The metal substrate 60 is cut in a plurality of vertical and horizontal cutting lines indicated by dotted lines, and the portion of B1 to be cut off is a size corresponding to the individual lid body 40 described above. Or it is a metal substrate of many pieces. In order to obtain the required strength while suppressing the size of the product in the height direction, the metal substrate 60 preferably has a plate thickness of, for example, about 0.08 to 0.1 mm.

In the following steps, for convenience of understanding, description will be made by enlarging and illustrating only the portion of the end view taken along the line CC in FIG. 7A. The processes proceed simultaneously, and all the B1 included in the metal substrate 60 are processed at the same time.
As shown in FIG. 7B, a photoresist 61 is applied to the front and back surfaces of the metal substrate 60. In this case, it is set as the pattern which formed the opening part 61a in any surface (illustrated surface) (ST21).
Next, the Kovar is immersed in an etching solution that can be etched, and wet etching is performed from one side corresponding to the side where the opening 61a is formed (ST22). As the etching solution, for example, an etching solution of iron alloy or nickel alloy can be used, and a ferric chloride solution or the like can be used. Alternatively, in this case, dry etching such as plasma ion etching may be performed from one side.
As a result, as shown in FIG. 7C, since the side etching proceeds along the peripheral edge of the opening 61a along with the etching in the thickness direction, the taper-shaped penetration gradually decreases in diameter along the depth direction. A hole 42 is formed. At the same time, the inner surface of the through hole 42 becomes a rough surface 42a, and the through hole 42 is formed.

Next, as shown in FIG. 7D, after the resist is peeled off (ST23), as shown in FIG. 7E, the metal substrate 60 on which the through holes 42 are formed is again immersed in the etching solution described above. The entire surface is etched (ST24). Since the purpose of this etching is to roughen the entire exposed surface of the metal substrate 60, it may be shorter than the etching time when the through hole 42 is formed.
Thereby, the front and back surfaces of the metal substrate 60 are made rough surfaces 60a.

Subsequently, as shown in FIG. 8F, a glass plate 62 is placed on the metal substrate 60 (ST25). Here, the glass plate 62 having a size substantially the same as that of the metal substrate 60 shown in FIG. In the following steps, the glass plate 62 is heated and melted, and each through hole 42 is simultaneously filled with molten glass. Therefore, the size of the glass plate 62 is a size necessary for this purpose. . And if the external dimensions of the metal substrate 60 and the glass plate 62 are matched, the operation becomes easy. It is preferable to select the glass plate 62 that has a thermal expansion coefficient approximate to that of the material constituting the lid body 40. In this respect, the glass used is borosilicate glass or Kovar glass. Etc. are suitable.
Here, the thickness t1 of the glass plate 62 is relatively thick, and as will be described later, the necessary amount of material for filling the through hole 42 as molten glass is ensured and will be described later. The polishing margin for the polishing process is obtained. From such a point, the thickness t1 is preferably about 0.1 to 0.2 mm in relation to the thickness of the metal substrate 60 to be the lid 40.

Next, the thing of the state of FIG.8 (f) is accommodated in suitable heating means, for example, heating furnaces, such as a high frequency and electric furnace, and is heated (ST26). This heating cannot be performed using a reducing flame, and a degassing step is performed immediately before the heating. Thereafter, heating is performed at 1000 to 1200 degrees (Celsius, hereinafter, all temperature notations are “Celsius”) for a predetermined time, and FIG. As shown in g), the molten glass material is filled into the through hole 42 as the glass filling portion 64 by melting.
In this state, the lower end portion 65 of the glass filling portion 64 may be exposed from the through hole 42 as illustrated.

Therefore, as shown in FIG. 8 (h), after the molten glass is hardened, the exposed lower end 65 and the portion of the surface portion 63 of the glass plate shown in FIG. 8 (g) are polished (ST27). . By this polishing process, the front and back surfaces of the glass plate 62 are mirror-polished.
Thus, the glass plate 62 filled in the through hole 62 is firmly joined by the anchor effect because the inner surface of the through hole 62 is a rough surface 62a. In addition, since the through hole 42 is tapered and the bonding area is increased as compared with a hole whose hole diameter does not change in the length direction of the hole, the glass plate 62 and the through hole 42 are also in this respect. The joint strength with is high.

Next, as shown in FIG. 8 (i), a corrosion-resistant film 70 is formed in a size that covers the peripheral portion of the through hole 42 of the metal substrate 60 and the entire lower surface in the drawing (ST28). In the case of wet etching, for example, an organic resist can be used as the corrosion resistant film. Then, the glass exposed from the corrosion-resistant film 70 is removed by wet etching (ST29).
Alternatively, this etching may be performed by dry etching. In this case, a corrosion resistant film is formed on the periphery of the through hole 42 of the metal substrate 60 (not shown). This corrosion-resistant film can be formed, for example, by forming a base layer of chromium (Cr) and depositing gold (Au) thereon by sputtering. Thereafter, the glass material covering one side of the metal substrate 60 is removed by dry etching on one side from above. In this dry etching, for example, the workpiece is housed in an airtight chamber, evacuated, and ion-etched by plasma discharge using CF ₄ or the like as a filling gas to remove the glass plate 62 exposed from the corrosion-resistant film. be able to.

As a result, as shown in FIG. 8 (j), the glass 43 described in FIG. 2 provided with the insertion portion 46 and the flange portion 44 to the through hole 42 is formed, and this flange portion 44 is formed on the surface of the metal substrate 60. In this respect, a strong bonding strength is realized.
Next, as shown in FIG. 9 (k), the corrosion resistant film is removed (ST30), and as shown in FIG. 9 (l), the front and back surfaces of the metal substrate 60 are covered with nickel by electrolytic plating (ST31). Finally, by cutting the metal substrate 60 along the vertical and horizontal dotted lines described with reference to FIG. 7A, the lid body 40 having B1 as a unit is completed.

(Piezoelectric vibrating piece joining process)
Next, the piezoelectric vibrating piece 32 is bonded onto the electrode portion 31 of the package 37 (ST41). That is, as described in FIGS. 1 and 2, the conductive adhesive 47 is applied on the electrode portion 31 of the package 37, and the portions of the lead electrodes 38 a and 39 a of the base portion 51 of the piezoelectric vibrating piece 32 are formed thereon. The electrode 31 and the piezoelectric vibrating piece 32 are electrically and mechanically joined by placing and curing the conductive adhesives 47 and 47. In this manner, the piezoelectric vibrating piece 32 is joined in a cantilever manner to the first substrate 55 that is an insulating base.

Further, the lid is sealed by bonding the package 37 and the lid 40 in a vacuum atmosphere (ST42).
FIG. 10 shows a state in which a jig J such as an electrode roller is held in contact with the lid 40, the seam ring 37a is melt-cured by Joule heat, and the lid is sealed by seam welding.
Subsequently, as described in FIG. 2, the laser beam LB or the like is transmitted from the outside of the lid body 40 through the glass 43 to irradiate the metal film 53 and / or 54 described in FIG. 3 of the piezoelectric vibrating piece 32. A part of it is evaporated and the frequency is adjusted by the mass reduction method (ST43). Here, as shown in FIG. 1, when the through-hole 42 exposes the metal film of both vibrating arms 35 and 36, a part of the metal film of each vibrating arm can be evaporated, It is preferable that the bending balance of both vibrating arms 35 and 36 can be adjusted.
Thereafter, a necessary inspection is performed (ST44), and the piezoelectric device 30 is completed.

As described above, in the piezoelectric device manufacturing method according to this embodiment, since the opening used for frequency adjustment is provided in the metal lid 40 in the step of forming the lid 40, even the very thin lid 40 is externally provided. An opening filled with glass 43 can be provided. For this reason, in the frequency adjustment step after sealing the lid, the metal film of the piezoelectric vibrating piece 32 in the package 37 can be irradiated with the external heating light beam LB through the glass that transmits light. In this way, the piezoelectric device 30 that has been frequency-adjusted after lid sealing and has performed precise frequency matching is resistant to external impact because the lid 40 is not glass, and is not easily damaged.
In this case, since the metal substrate 60 capable of separating at least a plurality of lids is processed in the step of forming the lid 40, a plurality or a large number of lids can be processed at a time, and the processing efficiency is excellent. Yes. In addition, the glass 43 to be filled in the through holes 42 is filled by melting a large glass plate 62 in a state where it is stacked on the metal substrate 60. Therefore, the glass tablet is positioned and fitted to each opening as in the conventional case. It is not necessary to reduce the size of the lid, and the glass material can be filled without difficulty even if the through hole is an opening made of a very small through hole.

FIG. 11 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 and other embodiments of the present invention such as the piezoelectric device 30 and modifications are attached to the CPU 301, and the output frequency thereof is determined by a predetermined frequency dividing circuit (not shown) incorporated in the CPU 301. The clock signal is adapted to the control contents. The piezoelectric device attached to the CPU 301 may be a piezoelectric vibrator or a piezoelectric oscillator.

  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 30 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. In this case, the lid is not damaged even if it receives an impact from the outside, so that 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 is applicable to all piezoelectric devices regardless of the names of piezoelectric vibrators, piezoelectric oscillators, etc., as long as they are covered with a package or a box-shaped lid and accommodate a piezoelectric vibrating piece inside. Can be applied to.

The schematic plan view which shows embodiment of the piezoelectric device of this invention. The AA line schematic sectional drawing of FIG. FIG. 2 is a schematic perspective view of a piezoelectric vibrating piece used in the piezoelectric device of FIG. 1. FIG. 4 is an end view taken along line BB in FIG. 3. FIG. 6 is a schematic cross-sectional view showing a modification of the piezoelectric device in FIG. 1. The flowchart which shows embodiment of the manufacturing method of the piezoelectric device of FIG. The figure which shows sequentially the manufacturing process of the cover used for the piezoelectric device of FIG. The figure which shows sequentially the manufacturing process of the cover used for the piezoelectric device of FIG. The figure which shows sequentially the manufacturing process of the cover used for the piezoelectric device of FIG. Explanatory drawing which shows an example of lid sealing 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. The figure which shows the structure of the cover body of the conventional piezoelectric device.

Explanation of symbols

  30, 30-1 ... Piezoelectric device, 32 ... Piezoelectric vibrating piece, 35, 36 ... Vibrating arm, 31 ... Electrode, 40 ... Lid, 41 ... Adjustment window , 43... Glass, 47... Conductive adhesive, 55... First substrate (insulating base), 56.

Claims (9)

Forming at least a number of through holes corresponding to the number of lids on a metal substrate having a size capable of separating at least a plurality of lids;
Placing a glass plate having a size corresponding to the metal substrate on the metal substrate;
Filling the melted glass material into each through hole by melting the glass plate;
And a step of cutting the metal substrate so as to be the size of each of the lids. A method for manufacturing a piezoelectric device in which a piezoelectric vibrating piece is accommodated in a package and hermetically sealed by a lid,
An individual forming step for separately forming the package, the piezoelectric vibrating piece, and the lid;
Bonding the piezoelectric vibrating piece to an insulating substrate constituting the package;
A lid sealing step for hermetically sealing the package with the lid;
And a frequency adjusting step of irradiating a heating light beam to a metal film formed on the piezoelectric vibrating piece from the outside of the package,
In the step of forming the lid,
Forming at least a number of through-holes corresponding to the number of the lids on a metal substrate made of a metal material having a thermal expansion coefficient approximate to that of the package, the size being such that at least a plurality of lids can be separated; ,
Placing a glass plate having a size corresponding to the metal substrate on the metal substrate;
Filling the melted glass material into each through hole by melting the glass plate;
Cutting the metal substrate so as to be the size of each individual lid, and
In the frequency adjusting step, a heating light beam is applied from the outside of the package to the metal film of the piezoelectric vibrating piece in the package via the glass material filled in the opening of the lid. A method for manufacturing a piezoelectric device, wherein the frequency is adjusted by irradiating and evaporating a part of the metal film.   The step of forming the through hole in the step of forming the lid body is characterized in that the through hole is formed by wet etching from one main surface of the metal substrate. Of manufacturing a piezoelectric device.   4. The method according to claim 2, wherein, in the lid forming step, the surface of the metal substrate is etched to be a rough surface after the through hole is formed and before the glass plate arranging step. The manufacturing method of the piezoelectric device in any one.   In the step of forming the lid, in the glass plate arrangement step, a glass plate having a thickness greater than the thickness required for filling of the molten glass is used, and the through hole has the above-described glass plate. 5. The method of manufacturing a piezoelectric device according to claim 2, wherein after the step of filling the molten glass material, the surface is mirror-polished to reduce the thickness.   6. The method for manufacturing a piezoelectric device according to claim 2, wherein the periphery of the through hole has a shape in which small curved surfaces are continuous. A piezoelectric device in which a piezoelectric vibrating piece is accommodated in a package hermetically sealed by a metal lid,
The lid is
At least a number of through holes corresponding to the number of the lids are formed in a metal substrate having a size capable of separating at least a plurality of lids, and a glass plate having a size corresponding to the metal substrate is overlaid on the metal substrate. A piezoelectric device comprising an adjustment window portion used for frequency adjustment provided by melting the glass plate and filling the melted glass material into each through-hole. . A mobile phone device using a piezoelectric device in which a piezoelectric vibrating piece is housed in a package hermetically sealed by a metal lid,
The lid is
At least a number of through holes corresponding to the number of the lids are formed in a metal substrate having a size capable of separating at least a plurality of lids, and a glass plate having a size corresponding to the metal substrate is overlaid on the metal substrate. A control clock is provided by a piezoelectric device provided with an adjustment window portion used for frequency adjustment, which is provided by filling the glass material melted into each through-hole by melting the glass plate. A cellular phone device characterized in that a signal is obtained. An electronic device using a piezoelectric device in which a piezoelectric vibrating piece is housed in a package hermetically sealed by a metal lid,
The lid is
At least a number of through holes corresponding to the number of the lids are formed in a metal substrate having a size capable of separating at least a plurality of lids, and a glass plate having a size corresponding to the metal substrate is overlaid on the metal substrate. A control clock is provided by a piezoelectric device provided with an adjustment window portion used for frequency adjustment, which is provided by filling the glass material melted into each through-hole by melting the glass plate. An electronic device characterized in that a signal is obtained.

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