JP2001144572A - Ceramic container and crystal vibrator using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic container of a crystal vibrator made of a large- sized crystal wafer, and to provide a crystal vibrator using the container. SOLUTION: In the recessed ceramic container consisting of a bottom wall and a sidewall that contains an upper face of a crystal chip is directed to an open edge, a crystal terminal electrode 11 connected to a lead electrode 7 extended to an outer circumference of an upper face of the crystal chip with a conductive joining material 8 is formed in an inner circumference of the sidewall. In the crystal vibrator 2 formed by connecting the lead electrode 7 extended to the outer circumference of the upper/lower face of the crystal chip to a crystal terminal electrode 4 in the ceramic container, the terminal electrode 4 is provided to the inner circumference of the sidewall of the ceramic container and connected to the lead electrodes 7 of the crystal chip with the conductive joining material 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrial technical field of a concave ceramic container and a crystal resonator for surface mounting in which a crystal piece is hermetically sealed, and is particularly suitable for mass production to ensure electrical connection. Related to a ceramic container.

[0002]

2. Description of the Related Art Quartz resonators are widely used in various electronic devices including communication devices as frequency and time reference sources or filter elements. in recent years,
For example, as typified by mobile phones, electronic devices have been further miniaturized and spread, and accordingly, crystal oscillators have also been required to be reduced in size and supplied in large quantities. Further, in order to make effective use of the communication frequency, a higher frequency of the crystal resonator is required. In order to meet such demands, for example, a thin quartz crystal resonator manufactured from a large quartz wafer by using a photograph and an etching technique is expected.

(Example of Prior Art) FIG. 10 is a cross-sectional view of a quartz oscillator for explaining a conventional example. The crystal unit accommodates a crystal blank 2 in a concave ceramic container (container main body) 1 and joins and seals a metal cover 3 by seam welding. The container body 1 is made of a laminated ceramic in which the bottom wall 1a and the side wall 1b are laminated and fired, and has crystal terminal electrodes (referred to as crystal terminals) 4 (ab) on both ends of the bottom surface of the concave portion. The crystal terminal 4 (ab) extends as a mounting electrode 5 (ab) on the side surface and the bottom surface via the laminated surface of the container body 1. The electrodes on the side surfaces are formed by so-called through-hole processing in which a through-hole is provided and a conductive paste is applied to the inner periphery.
Reference numeral 12 in the drawing denotes a metal ring for welding which is soldered to the open end.

[0004] The crystal blank 2 is made of an AT cut of thickness shear vibration. Then, as shown in FIG. 11, for example, a hole is provided from one main surface side as an upper surface, and a thin portion 2 in a central portion is provided.
a is a vibration region, and the thick portion 2b of the outer peripheral portion is a holding region. Excitation electrodes 6 (ab) are formed on both main surfaces of the thin portion 2a, and the extraction electrodes 7 (ab) extend to the thick portions 2b which are opposite ends. This makes it possible to reduce the thickness of the vibration region (thin portion 2a) and increase the vibration frequency to, for example, 100 MHz or more, as compared with the case where the crystal blank 2 is a flat plate.

[0005] Then, the upper surface side having the hole is the container body 1.
The two ends of the crystal piece 2 extended from the extraction electrode 7 (ab) are accommodated as the open ends of the crystal terminal 4 (a) on the bottom surface of the concave portion.
b) is electrically and mechanically connected. That is, they are electrically connected and fixed by the conductive adhesive 8. In this case, a conductive adhesive 8 (referred to as an undercoat conductive adhesive 8a) is applied on the crystal terminal 4 (ab), the crystal blank 2 is placed, and a gap between the upper surface of both ends and the side wall 1b is formed. The conductive adhesive 8 (referred to as a top-coating conductive adhesive 8b) is embedded. Then, the top coat and the undercoat conductive adhesive 8 (ab) are simultaneously cured by, for example, heat, and the crystal blank 2 is fixed.

In such a case, as shown in FIG. 12, for example, a large quartz wafer 9 is masked and a large number of holes 10 are formed by etching. Next, the excitation and extraction electrodes 6 and 7 (ab) are formed on both main surfaces by, for example, vapor deposition using a new mask. Further, the space between the holes of the crystal wafer 9 is cut by a dicing saw or the like to obtain a large number of crystal blanks 2. Then, as described above, the crystal piece 2 is housed in the container body 1 and the cover is sealed to obtain a crystal resonator.

[0007]

[Problems to be Solved by the Invention]
However, in the crystal resonator having the above configuration, the extraction electrodes 7 (ab) are formed only on the main surfaces of both ends of the crystal blank 2. Therefore, the lower surface side extraction electrode (referred to as a lower surface extraction electrode) 7b and the crystal terminal 4a are directly opposed to each other to ensure electrical connection (conduction) by the undercoat conductive adhesive 8a. However, the extraction electrode on the upper surface side (the upper extraction electrode)
7a and the crystal terminal 4b are not directly opposed to each other with a gap in the height direction. In order to reduce the external dimensions, the gap between both ends of the crystal blank 2 and the side wall 1b of the container body 1 is extremely small.

For this reason, as shown in FIG. 13, the top-coating conductive adhesive 8b applied from the upper surface side is rounded due to viscosity and surface tension and reaches the undercoating conductive adhesive 8a and the crystal terminal 4b. do not do. Or, even if you arrive,
There is a possibility that the contact area may be reduced to make electrical conduction uncertain. When the thickness of the thick portion 2b is large,
Since the gap between the upper surface extraction electrode 7a and the crystal terminal 4b is also large, and the path of the top coating conductive adhesive 8b is long,
There was also a risk that the electrical resistance would increase. In any case, since the extraction electrode 7a and the crystal terminal 4b do not directly face each other, there is a problem that the connection state by the overcoating conductive adhesive 8b cannot be confirmed.

The upper and lower extraction electrodes 7 (ab) at both ends are provided.
This problem can be solved by forming by folding back to the opposite surface via the side surface as in the conventional case. For this reason, the crystal wafer 9
In this state, for example, it is conceivable to provide a through hole (not shown) and provide an electrode from the side surface to the back surface. However, it is extremely difficult to form an electrode in a through hole by vapor deposition, and the number of steps is increased to complicate the process, which is not suitable for mass production.

(Purpose of the Invention) An object of the present invention is to provide a container body which is suitable for mass production and has a reliable electrical connection, and a crystal resonator using the same.

[0011]

The basic solution of the present invention is to provide a crystal terminal (referred to as a side wall terminal) 11 on the inner periphery of the side wall of the container body 1.

[0012]

According to the present invention, the side wall terminal 11 provided on the inner periphery of the side wall of the container body 1 and the upper surface extraction electrode 7a of the crystal blank 2 are electrically connected by the conductive bonding material 8. Thereby, the upper surface extraction electrode 7a and the side wall terminal (crystal terminal) 1 made of the conductive bonding material 8
1 and can be visually confirmed. Hereinafter, an embodiment of the present invention will be described.

FIGS. 1 and 2 are views for explaining a first embodiment of the present invention. FIG. 1 is a sectional view of a quartz oscillator, and FIG. 2 is a partial view of a container body. The same parts as those in the prior art are denoted by the same reference numerals, and description thereof will be simplified or omitted. The crystal unit is hermetically sealed in the container main body 1 having a concave shape as described above, with the upper surface provided with the hole of the crystal blank 2 as the opening end side. In this embodiment, the side wall 1b is connected to the upper side wall 1
As two layers of b1 and lower wall 1b2, side wall terminals 11 (ab) are provided on the inner periphery of the side wall of lower wall 1b2 at both ends.
The side wall terminal 11 (ab) is electrically connected to the crystal terminal 4 (ab) on the bottom surface and the mounting electrode 5 (ab).

The side wall terminal 11 (ab) of the lower side wall 1b2 is
For example, a through hole 13 is formed in a flat green sheet (ceramic material) (FIG. 3), and a copper paste (not shown) is supplied and applied to the inner periphery (through hole processing). Then, after punching out the central portion indicated by the dotted line, the bottom wall 1a and the upper side wall 1b1 are laminated and formed by integral firing.
Normally, the crystal terminal 4 (ab) and the mounting electrode 5 (ab)
And gold plating treatment.

In such a device, the undercoat conductive adhesive 8a is applied to the crystal terminals 4 (ab) as described above, and the bottom surfaces of both ends of the crystal blank 2 are placed. An overcoating conductive adhesive 8b is applied. That is, the top coating conductive adhesive 8b buries the gap between both ends of the crystal blank 2 and the inner periphery of the side wall, and particularly electrically connects the upper surface extraction electrode 7a and the side wall terminal 11a.

With such a configuration, the lower surface extraction electrode 7
The b and the crystal terminal 4a ensure electrical continuity by the undercoat conductive adhesive 8a interposed therebetween as described above. Then, the upper surface extraction electrode 7a is provided with a top coating conductive adhesive 8b.
Therefore, even if the top-coating conductive adhesive 8b does not reach the undercoating conductive adhesive 8a and the crystal terminal 4b, the crystal terminal 4b and the mounting electrode 5
ensure electrical continuity with b.

When the thickness of the thick portion 2b of the crystal blank 2 is larger than the gap between the crystal blank 2 and the side wall 1b, the path length of the conductive adhesive 8 can be shortened to reduce the conduction resistance. . In this embodiment, the side wall 1b is formed as the upper side wall 1b1,
The lower side wall 1b2 is formed from the lower side wall 1b2.
Since 1 (ab) is provided, an electrical short circuit with the metal ring 12 is prevented.

In this example, the extraction electrode 7 (ab) extends to the center of both ends and holds the same. However, for example, the extraction electrode 7 (ab) extends to opposite corners of both ends and holds the diagonal. Well,
Further, the extraction electrode 7 (ab) may be formed along both sides of both ends to hold an arbitrary part (not shown). further,
The extraction electrode 7 (ab) may extend to both sides of one end to hold only one end (not shown).

In order to improve the workability by eliminating the directionality, the crystal terminal 4 (ab) and the side wall terminal 11 (ab) are provided at both ends to be symmetrical. 11b may not be provided. The crystal terminal 4b may not be provided on the other end of the upper surface extraction electrode 7a (not shown).

[0020]

Second Embodiment FIGS. 4 and 5 are views for explaining a second embodiment of the present invention. FIG. 4 shows a quartz crystal as a filter element (a so-called MCF, Monolithic Crystal Filter) to which the present invention is applied. FIG. 5 is a plan view of the container body viewed from the lower side wall. The description of the same parts as described above is omitted or simplified. The crystal unit is configured such that a crystal blank 2 having a hole as described above is housed in a container body 1, and a metal cover 3 is provided.
(See FIG. 1). The crystal blank 2 has an input / output electrode 14 (ab) on the bottom surface of the thin portion (vibration region) 2 a,
On the back surface, a common electrode 14c facing this is provided. Each extraction electrode 15 (abc) extends from the input / output electrode 14 (ab) to the center of both ends in the long side direction, and from the common electrode 14 c to the center (hereinafter referred to as the center) of one end in the short side direction. .
These are integrally formed on the large crystal wafer 9 by using the photo, printing and etching techniques as described above.

The container body 1 has input / output and ground crystal terminals 4 (cde) on the bottom surface (bottom wall 1a) and input / output side wall terminals 11 on the inner periphery of the lower wall 1b2 at both ends.
(Cd). The side wall terminal 11 (cd) is electrically connected to the crystal terminal 4 (cd) and a mounting electrode (not shown) formed on the outer surface, respectively.

Then, for example, an undercoat conductive adhesive 8a is applied to the crystal terminal 4 (cde), and the crystal blank 2 is positioned and fixed. Further, an upper coating conductive adhesive 8b is applied from both upper surfaces of both ends of the crystal blank 2 so as to be embedded between the crystal blank 2 and the inner periphery of the side wall, and the upper surface extraction electrode 15 (ab) and the side wall for input / output are used. Connect to terminal 11 (cd) (see FIG. 1).

With such a configuration, as described above,
The lower surface extraction electrode 15c for grounding and the crystal terminal 4e ensure electrical continuity with the undercoating conductive adhesive 8a. The upper surface lead-out electrode 15 (ab) is formed by applying the top-coating conductive adhesive 8 b to the undercoating conductive adhesive 8 a and the crystal terminal 4 (c).
Even if it does not reach d), electrical conduction between the crystal terminal 4 (cd) and the mounting electrode is ensured by the side wall terminal 11 (cd). Then, the path length of the conductive adhesive 8 can be shortened, and the conduction resistance can be reduced.

In this embodiment, in order to make the crystal blank 2 symmetrical to facilitate the connection operation, the ground extraction electrode 15c extends to the center of both ends in the short side direction and responds to this. A crystal terminal 4e may be provided on the bottom surface of the hole (not shown).

[0025]

Others In the above embodiments, the undercoat conductive adhesive 8a and the overcoat conductive adhesive 8b are used at the extending ends of the extraction electrodes 7 and 15, for example, the extension of the lower extraction electrodes 7b and 15c is used. The protruding end portion is only the undercoating conductive adhesive 8a. The extending end portions of the upper surface extraction electrodes 7a and 15 (ab) may be made only of the overcoating conductive adhesive 8b (not shown). In this case, the work of applying the conductive adhesive 8 is reduced by half, so that the workability is improved.

Although the crystal blank 2 is housed with the upper surface provided with the hole as the opening side of the container body 1, the same applies to the case where the crystal blank 2 is fixed with the lower surface of the flat portion as the opening side. . Although the crystal blank 2 having a hole is used, the thin blank 2 is basically used even if it is flat (FIG. 6).
even if there is a thick portion 2b only on one end side with respect to
(See FIG. 8). Further, a thin portion 2a and a thick portion 2b may be provided by providing holes from both sides (FIG. 8). In short, the extraction electrode 7 is provided only on the outer circumference on both main surfaces of the crystal blank 2 without being folded.
15 can be applied as long as the crystal piece 2 is extended.

Although the cover is formed by seam welding as a metal, it can be arbitrarily selected by welding with an electron beam or sealing with glass or resin. In addition, the thickness of the crystal terminal 4 is increased to provide a gap for vibration between the container body 1 and the crystal piece 2. However, for example, a recess may be provided on the bottom surface and a gap may be provided between the two (not shown). Although only the crystal blank 2 is accommodated in the container body 1, a concave portion may be provided on the bottom surface or the back surface to accommodate an electronic element such as an IC chip, and a crystal oscillator or a filter may be formed (not shown).

The side wall 1b is formed as a two-layer lower wall 1b2.
The side wall terminal 11 is provided to measure the insulation with the metal ring 12. For example, the metal ring 12 is provided on the outer peripheral side avoiding the inner peripheral upper surface of the opening end of the container body 1, and short-circuiting with the conductive adhesive 8 is performed. It may be prevented (FIG. 9). The conductive adhesive 8 may be a metal (a brazing material) such as solder, for example. The conductive adhesive 8 may be a conductive bonding material having conductivity and a function of mechanically bonding.

The undercoating and topcoating conductive adhesive 8 (a
b) was made conductive, but the undercoat conductive adhesive 8a
May be used only as a mechanical connection as an insulating adhesive, and electrical continuity may be measured only with the overcoating conductive adhesive 8b. In this case, since the undercoated insulating adhesive is used for mechanical fixing and the overcoated conductive adhesive 8b is used for electrical conduction, the range of options for each of the insulating and conductive adhesives is expanded. , Increase design freedom. And the side wall terminal 1
Although 1 was formed by through-hole processing, for example, vapor deposition or plating may be used, and these may be arbitrarily formed.

In short, the purpose of the present invention is to provide a side wall terminal 11 connected to the upper surface lead-out electrodes 7a, 15 (ab) of the crystal blank 2 on the inner circumference of the side wall of the container body 1 so as to ensure electrical conduction. Yes, those based on such a purpose are included in the technical scope of the present invention, including other appropriate changes including the above.

[0031]

According to the present invention, there is provided a ceramic container which is suitable for mass production and has a reliable electrical connection (conduction) because a side wall terminal is provided on the inner periphery of the side wall of the container body and connected to the upper electrode of the crystal piece. A crystal resonator using this can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a crystal unit illustrating one embodiment of the present invention.

FIG. 2 is a partial view of a container main body illustrating one embodiment of the present invention.

FIG. 3 is a plan view of a base ceramic on a lower side wall for explaining an embodiment of the present invention.

FIG. 4 is a view of a crystal blank for explaining another embodiment of the present invention.

FIG. 5 is a plan view of a container body viewed from a lower side wall for explaining another embodiment of the present invention.

FIG. 6 is a view of another crystal blank applied to the present invention.

FIG. 7 is a view of another crystal piece applied to the present invention.

FIG. 8 is a diagram of another crystal blank applied to the present invention.

FIG. 9 is a partial view of another container main body applied to the present invention.

FIG. 10 is a cross-sectional view of a crystal unit illustrating a conventional example.

FIG. 11 is a view of a crystal piece for explaining a conventional example.

FIG. 12 is a view of a crystal wafer for explaining a conventional example.

FIG. 13 is a partial cross-sectional view illustrating a problem of a conventional example.

[Description of Signs] 1 container body, 2 crystal pieces, 3 metal cover, 4 crystal terminals, 5 mounting electrodes, 6 excitation electrodes, 7, 15 extraction electrodes,
8 conductive adhesive, 9 quartz wafer, 10 holes, 11
Side wall terminal, 12 metal ring, 13 through hole, 14a
Input electrode, 14b Output electrode, 14c Common electrode.

Claims (4)

[Claims] 1. A concave ceramic container having an upper surface of a quartz piece as an opening end and a lead electrode extending to an outer periphery of a main surface on an upper surface side of the quartz piece and a conductive bonding material in a concave ceramic container having a bottom wall and side walls. A ceramic container, wherein a crystal terminal electrode electrically connected is formed on the inner periphery of the side wall. 2. An extraction electrode which is housed in a concave ceramic container having a bottom wall and a side wall with an upper surface of a crystal blank as an opening end and extends to an outer periphery of a main surface of upper and lower surfaces of the crystal blank. In the crystal resonator connected to the crystal terminal electrode in the inside, at least one of the crystal terminal electrodes is provided on the inner periphery of the side wall of the ceramic container, and the drawing extends to the outer periphery of the main surface on the upper surface side of the crystal piece. A crystal unit electrically connected to an electrode by a conductive bonding material. 3. The crystal unit according to claim 2, wherein the extraction electrode extends from opposing excitation electrodes formed on upper and lower surfaces of the crystal blank. 4. The crystal unit according to claim 2, wherein said extraction electrode extends from an input / output electrode formed on the upper and lower surfaces of said crystal blank or a common electrode facing said input / output electrode.