JP3014882B2 - Package base substrate for built-in capacitor type piezoelectric oscillator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a package base substrate for a built-in capacitor type piezoelectric oscillator.

[0002]

2. Description of the Related Art As a built-in capacitor type piezoelectric oscillator, a package base substrate is a dielectric ceramic substrate,
In some cases, the dielectric ceramic substrate itself functions as a capacitor. The package base substrate of the built-in capacitor type piezoelectric oscillator is generally manufactured in the following two ways. One of them is obtained by forming a base substrate (dielectric ceramic substrate) of each unit into a predetermined shape by dry press molding and firing. And
Electrodes are formed on the front, back and side surfaces of the base substrate of each unit, a piezoelectric element is fixed on a predetermined electrode, and an upper cap is further joined on the base substrate to produce a built-in capacitor type piezoelectric oscillator. .

As shown in FIG. 3, a dielectric ceramic substrate 20 has a slit (horizontal slit) 21 extending in the horizontal direction as a crack for breaking and a slit (vertical slit) 22 extending in the vertical direction. They are formed in parallel at equal intervals. Then, electrodes are formed on the front surface and the back surface of each unit 23 formed by the vertical and horizontal slits, and the horizontal slit 21 is broken.
Splits into bars that are connected horizontally. Subsequently, a horizontal electrode is formed on the break surface (side surface) of the bar, a piezoelectric element is fixed on a predetermined electrode, and an upper cap is bonded on the unit 23. Next, the vertical slit 22 is broken and separated into individual units 23 to obtain a built-in capacitor type piezoelectric oscillator.

[0004]

However, when a piezoelectric oscillator is manufactured for each unit, there is a problem that the cost is increased because the oscillator is manufactured one by one.
Further, in the case of manufacturing using vertical and horizontal slits, the break is caused by the vertical and horizontal slits, so that not only the cost of the break is increased, but also the vertical slit may be broken at the time of the horizontal slit break, and the yield is reduced. In addition, at the time of breaking the horizontal slit, it is difficult to form a horizontal electrode on the break surface after the break because it can not be broken straight along the horizontal slit and is easily broken, and the area between the electrodes becomes uneven. As a result, the capacitance of the capacitor on the side surface tends to fluctuate.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a piezoelectric oscillator using vertical and horizontal slits to reduce the break cost, reduce the defective rate at the time of horizontal slit break,
It is an object of the present invention to provide a package base substrate for a built-in capacitor type piezoelectric oscillator that prevents deterioration in quality due to a defect in a break shape and improves productivity.

[0006]

In order to achieve the above object, a package base substrate for a built-in capacitor type piezoelectric oscillator according to the present invention comprises a dielectric ceramic substrate having a narrow hole extending from near one end to near an opposite end. Are formed in parallel at regular intervals, and break slits are formed in parallel at regular intervals at the narrow holes located at both ends, and the narrow holes are located at the same position between each slit and It has a plurality of wide portions at equal intervals, and only the slits located at both ends of the break slits extend to both end edges of the dielectric ceramic substrate across all the parallel narrow holes. And

In this package base substrate, one is not a slit for breaking both vertically and horizontally, one is a slit for breaking and the other is a narrow narrow hole, and each unit (individual base substrate) formed by the slit and the narrow hole is formed. After the electrodes are provided on the front and back surfaces, if the slits located at both ends of the slits are broken, a plurality of bars in which the units are continuous can be obtained at a time. In other words, since the base substrate is separated into a bar shape in advance by the narrow holes, it is not necessary to break the horizontal slits in order as in the conventional case, which not only reduces the break cost, but also causes a break failure at the time of breaking the horizontal slits. Nothing happens and the side of the bar is straight and flat.

In the base substrate of the present invention, the break slits may be formed at substantially the same depth. However, when the base substrate is divided into bars, the slits at both ends are broken first. It is preferable to make the bar deeper than the other slits to make it easier to break and to prevent the bar from breaking. Further, the depth of the slit is desirably about 5 to 70%, more desirably about 30 to 65% of the thickness of the base substrate, and BaTiO ₃ and SrTiO ₃ are exemplified as the dielectric material as the material of the substrate. You.

On the other hand, the narrow hole may have a width necessary to completely separate the base substrate in a bar shape in advance, but at least a width of 0.1 mm or more is required.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a base substrate of the present invention will be described based on embodiments. FIG. 1 is a plan view of a base substrate according to the embodiment. In the dielectric ceramic substrate 10 as a base substrate, elongated narrow holes 11 extending from near one end (left end) to near the other end (right end) are formed in parallel at equal intervals, and the narrow holes located at both ends are formed. Break slits 12 crossing between 11a and 11b are formed in parallel at equal intervals. Of the slits 12, the slits 1 located at both ends
2a and 12b extend to one end (upper end) and the other end (lower end) of the base substrate 10 across the left end and right end of all the narrow holes 11 arranged in parallel. A large number of units (individual base substrates) 13 are formed on the base substrate 10 by the narrow holes 11 and the slits 12.
Therefore, the interval between the narrow holes 11 is set to a predetermined width of the unit 13, and the interval between the slits 12 is set to a predetermined length of the unit 13.

The dummy portions 15 and 1 are formed along the four sides of the base substrate 10 by the narrow holes 11 and the slits 12.
6, 17, 18 are formed, and the dummy portions 15 to 18 are formed.
Is an unnecessary part. Also, as described above, the slit 1
The depth of 2 is about 5 to 70% of the thickness of the base substrate 10, and only the slits 12a and 12b at both ends are deeper than the other slits 12, so that a break is easily caused first. In this embodiment, the slits 12a at both ends are provided.
The slits 12 other than 12b are narrow holes 11a, 1 at both ends.
Although it extends to 1b, it may be extended halfway through the dummy portions 15, 17.

As shown in an enlarged view of FIG. 2, the shape of the narrow hole 11 is not a simple linear shape but a pattern in which wide portions 19 are present at equal intervals. Wide part 19 shown here
Are formed on both side surfaces of each unit 13, respectively. This is because when forming three external electrodes as a built-in capacitor type piezoelectric oscillator, for example, this wide part (after being divided into bars) This is to make it easy to form three electrodes with a uniform width on the side surface of the unit using the notch 19).

Next, a case where a capacitor built-in type piezoelectric oscillator is manufactured using the base substrate 10 shown in FIG. 1 will be briefly described. First, after forming electrodes on the front and back surfaces of each unit 13 of the base substrate 10, the slits 12 at both ends are formed.
a, 12b are broken to remove the dummy portions 15 to 18, and the unit 13 obtains a plurality of bars continuous in the length direction. Since the bars are completely separated in advance by the narrow holes 11, no break in the horizontal slit is required, and the side surfaces of the bars are straight and flat.

Subsequently, on the side surface of each bar, a horizontal electrode is formed in a portion other than the notch formed by the wide portion 19 of the narrow hole 11. Then, the piezoelectric element is fixed on the predetermined electrode with a conductive adhesive, and the upper cap is joined on the unit. Thereafter, the piezoelectric element is broken through the slit 12 and divided into individual units to obtain a built-in capacitor type piezoelectric oscillator.

[0015]

The package base substrate for a built-in capacitor type piezoelectric oscillator of the present invention has the following effects because it is configured as described above. (1) Instead of the conventional horizontal slit, a narrow hole is formed in advance to separate the base substrate into a bar shape. Therefore, the base substrate can be divided into a plurality of bars simply by breaking the break slits at both ends. Can be divided into Therefore,
There is no need to break the horizontal slit, so that the break cost can be reduced and the productivity can be improved. (2) Since no horizontal slit is required due to the narrow hole,
There are no defects such as cracks from the vertical slits due to the breaking of the horizontal slits, and the defect rate at the time of the break can be significantly reduced. (3) Since the horizontal slit is not required and the horizontal slit does not need to be broken, it is not only possible to eliminate the difficulty of forming the horizontal electrode due to the oblique cracking of the side surface of the unit due to the break of the horizontal slit, but also the unit. Side chipping can be prevented, and the quality is improved. (4) Since the side surface of the bar after division is straight and flat,
Variations in the capacitance of the capacitor due to the non-uniform area between the electrodes can be prevented, and the quality is improved. (5) When a break is made from the slits at both ends, unnecessary portions (dummy portions) along the four sides of the substrate are separated into four elongated portions, and the unnecessary portions may be mixed into the substrate in a subsequent process. And unnecessary portions can be reliably removed.

[Brief description of the drawings]

FIG. 1 is a plan view of a base substrate (dielectric ceramic substrate) according to one embodiment.

FIG. 2 is a partially enlarged view showing a shape of a narrow hole formed in a base substrate of FIG. 1;

FIG. 3 is a plan view of a base substrate according to a conventional example.

[Explanation of symbols]

 Reference Signs List 10 base substrate (dielectric ceramic substrate) 11 narrow hole 12 break slit 13 unit 15-18 dummy part

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H03H 9/00-9/76

Claims (1)

(57) [Claims] To 1. A dielectric ceramic substrate, a narrow hole that extends from near one end to near the opposite end formed in parallel at a predetermined interval, the break slits crossing between narrow hole located at opposite ends fixed Formed in parallel at intervals, said narrow holes
At the same position and at equal intervals between each slit
A plurality of wide portions, only away slit to position at both <br/> end of the break slits may extend all the narrow hole in parallel to the both edges of the dielectric ceramic substrate across each
A package base substrate for a built-in capacitor type piezoelectric oscillator, characterized in that: