JP2002353069A - Capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable capacitor by enabling desired capacitance to be obtained stably. SOLUTION: This capacitor is equipped with a substrate 1 equipped with terminals 9 at both ends and a shaft core 8 depressed around from the terminals 9, an insulating separator 11 made at the shaft core 8, and a conductive film 4 made on the surface of the substrate 4 and separated by the insulating separator 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor widely and usefully used in medium-to-high voltage circuits of small and thin electronic devices such as a modem card, a video camera, a digital still camera, and a notebook personal computer.

[0002]

2. Description of the Related Art Conventionally, a disk-type medium-voltage ceramic capacitor with a lead wire has been used for a medium-voltage circuit. However, recent advances in digital technology have made electronic devices smaller and thinner.
Along with this, surface mounting is progressing, and the chip rate of components is also increasing.

In accordance with such a trend, a multilayer chip type capacitor which is compatible with a thin type and which can be surface-mounted has been developed and used.

Here, a conventional multilayer chip type capacitor will be described. FIG. 5 is a perspective view showing a conventional multilayer chip capacitor, and FIG. 6 is a sectional view of the conventional multilayer chip capacitor. FIG. 6 is a sectional view taken along line AA of FIG.

In FIGS. 5 and 6, reference numeral 1 denotes a base made of a dielectric material. 2 is an internal electrode, and 3 is a terminal electrode. Reference numeral 20 denotes a multilayer chip capacitor.

As shown in FIGS. 5 and 6, a multilayer chip capacitor 20 has a rectangular parallelepiped shape, and an internal electrode 2 is formed on a base 1. The base 1 is formed by laminating dielectric layers, and the internal electrodes 2 are separated from each other by the dielectric layers. In addition, the internal electrode 2 and the terminal electrode 3 are configured to conduct at the end face of the base 1.

Further, other conventional capacitors are disclosed in JP-A-3-23211 and JP-A-10-8.
It is disclosed in 3935 gazette. These capacitors will be described with reference to FIGS.

FIG. 7 is a sectional view of a conventional capacitor. In FIG. 7, reference numeral 4 denotes a conductive film, reference numeral 5 denotes a gap, and reference numeral 6 denotes an exterior material formed of an insulating film. Reference numeral 30 denotes a capacitor.

As shown in FIG. 7, in the capacitor 30, a conductive film 4 is formed on the surface of a base 1 having a cylindrical shape or the like. The gap 5 is formed by laser trimming the conductive film 4 over the outer periphery of the base 1. It is formed. Then, the conductive film 4 is separated into a pair of electrodes, and is covered with the exterior material 6.

In this capacitor 30, it is possible to change the length of the gap 5 by changing the laser trimming pattern and obtain an arbitrary capacitance.

FIG. 8 is a sectional view of a conventional capacitor. In FIG. 8, reference numeral 7 denotes a concave portion, and reference numeral 40 denotes a capacitor.

As shown in FIG. 8, in the capacitor 40, a concave portion 7 is formed on the surface of the columnar base 1, and the surface of the protrusion between them forms the gap 5. Then, the conductive film 4 is formed on the surface of the base 1 except for the gap 5, and the conductive film 4 is further covered with the exterior material 6. The conductive film 4 is formed by immersing both ends of the gap 5 in a conductive paste and applying the conductive paste. At this time, the projecting portion between the recesses 7 allows the conductive paste to be blocked, and a predetermined gap 5 is formed.

In the capacitor 40, the gap 5 between the conductive films 4 can be formed with high precision even in dip coating, and the diameter of the exterior material 6 does not increase, and a high capacitance value can be obtained. That's what it says.

[0014]

However, the above-mentioned conventional capacitor has the following problems.

First, the conventional multilayer chip capacitor shown in FIGS. 5 and 6 has no exterior material formed between the terminal electrodes and the base 1 is exposed.
There is a problem that moisture easily penetrates from a gap between the dielectric layer constituting the base 1 and the internal electrode 2, and a short circuit occurs early in a moisture resistance load life test, resulting in poor reliability. In addition, there is also a problem that the bending strength after mounting on a printed substrate or the like is weak because of the laminated structure.

Further, the conventional capacitor shown in FIG. 7 has a problem that the center of the package 6 made of an insulating film becomes thick and a problem that the mountability is poor. Further, since the gap 5 serving as a capacitance gap is formed by laser-trimming the conductive film 4 over the outer periphery of the substrate 1, high-precision control is required to completely match the trimming start point and end point. However, in order to keep the width of the gap 5 constant, there is also a problem that the laser output and the rotation speed of the base 1 must be reliably controlled.

Further, in the capacitor shown in FIG. 8, a concave portion 7 is provided in the base 1, and the conductive paste is intercepted at the protrusion between the concave portions 7 to form the conductive film 4 by dip coating. Since both ends of the gap 5 are immersed in the conductive paste, the process becomes complicated, and it is also troublesome to immerse the projecting portions between the recesses 7 so that the conductive paste does not cross over. Further, since both ends of the gap 5 are immersed in the conductive paste, the conductive films 4 on both sides of the gap 5 may have a wavy shape.

Further, if the outer package material 6 is clearly protruded from the outer dimensions of the dielectric ceramic base 1, there is a problem at the time of mounting.
Suppressing the increase in the diameter of the exterior material 6 by the capacitor shown in FIG. 8 is not sufficient.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a highly reliable capacitor capable of stably obtaining a desired capacitance.

[0020]

In order to achieve the above object, the present invention provides a base having a terminal portion at both ends and a shaft core recessed over the outer periphery from the terminal portion; And a conductive film formed on the surface of the base and separated by the insulating separator.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is a substrate having a terminal portion at both ends, a shaft core recessed over the outer periphery from the terminal portion, and an insulating member formed at the shaft core portion. A capacitor comprising a separator and a conductive film formed on the surface of the substrate and separated by an insulating separator.The capacitor can perform the conductive film separation with high accuracy and has a desired capacitance. It can be obtained stably.

According to a second aspect of the present invention, there is provided a capacitor according to the first aspect, wherein the insulating separator is formed of a photosensitive resin, and the insulating separator can be formed with high precision.

According to a third aspect of the present invention, there is provided a capacitor according to the first or second aspect, further comprising an exterior material covering the shaft core portion between the terminal portions at both ends, thereby improving moisture resistance. be able to.

According to a fourth aspect of the present invention, there is provided a capacitor according to the third aspect, wherein the exterior material and the terminal portions at both ends are substantially flush with each other. Excellent mountability.

According to a fifth aspect of the present invention, there is provided a capacitor according to any one of the first to fourth aspects, wherein a terminal electrode is provided on the conductive film of the terminal portion, and the conductive film can be protected. At the same time, bonding to the substrate is easy.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(Embodiment 1) FIG. 1 is a perspective view showing a capacitor according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view showing the capacitor according to Embodiment 1 of the present invention. FIG. 2 is a sectional view taken along line AA of FIG.

In FIGS. 1 and 2, 1 is a base, 3 is a terminal electrode, 4 is a conductive film, 5 is a gap, and 6 is an exterior material. Furthermore,
Reference numeral 8 denotes a shaft core portion, 9 denotes a terminal portion, 10 denotes an inclined portion, 11 denotes an insulating separator, and 100 denotes a capacitor. In addition,
θ is the angle between the inclined portion 10 and the shaft core 8.

As shown in FIG. 1, the capacitor 100 is
The exterior material 6 is filled between the terminal portions 9 and has a substantially rectangular parallelepiped outer shape.

Further, as shown in FIG. 2, the base 1 has a terminal portion 9 at both ends and a shaft core portion 8 at the center.
The shaft core 8 is recessed over the outer periphery than the terminal 9. Then, the exterior material 6 is filled in the recessed portion.

An inclined portion 10 is formed between the shaft core portion 8 and the terminal portions 9 at both ends. By providing the inclined portion 10, the exterior material 6 can be reliably and stably filled. In the capacitor 100 according to the first embodiment of the present invention, air bubbles are trapped between the exterior material 6 and the base 1. It is almost none.

It is preferable that the angle θ between the inclined portion 10 and the shaft core portion 8 is 90 to 150 degrees.
If the angle is less than 90 degrees, bubbles are generated and the stable exterior material 6 is formed.
Is difficult to fill. In addition, when the temperature exceeds 150 degrees, the exterior material 6 to be filled becomes thin, and the moisture resistance decreases.
The reliability becomes worse.

Further, a conductive film 4 is formed on the surface of the substrate 1 having the above-described structure, and the conductive film 4 is separated from the shaft core portion 8 by the insulating separator 11 so as to provide the gap 5. Have been. Then, an exterior material 6 is formed to cover the conductive film 4 formed on the insulating separator 11, the shaft core portion 8, and the inclined portion 10.

A terminal electrode 3 is formed on the conductive film 4 of the terminal portion 9 not covered with the exterior material 6 so as to cover the conductive film 4. Note that the conductive film 4 exposed at the terminal portion 9 may be used as an electrode without providing the terminal electrode 3.

Further, the exterior member 6 and the terminal portion 9 are substantially flush with each other, and have a substantially rectangular parallelepiped outer shape, and are excellent in mountability as a chip capacitor. The external shape of the capacitor 100 is preferably a substantially rectangular parallelepiped because it is excellent in mountability, but may be a columnar shape or a polygonal shape as long as the mountability as a chip capacitor is not hindered.

Further, each configuration of the capacitor 100 will be described in detail.

First, the base 1 is prepared by mixing additives such as bismuth oxide, titanium oxide and manganese oxide and other sintering aids with a main component of a dielectric material such as strontium titanate and calcium titanate. Is composed of dielectric ceramics obtained by firing

Further, the base 1 has a shape in which the central shaft core portion 8 is depressed over the outer periphery than the terminal portions 9 at both ends thereof,
An inclined part 10 is provided between the shaft core part 8 and the terminal part 9.

As a method of forming the base 1, the above-described dielectric material is charged into a mold, formed into a predetermined shape, and fired. Alternatively, the shaft core 8 and the inclined portion 10 may be formed by cutting the center of the fired substantially rectangular parallelepiped base body.

FIG. 3A is a sectional view showing a capacitor according to the first embodiment of the present invention.
It is a B sectional view. As shown in FIG.
Is similar in shape to the terminal portion 9. That is, in the first embodiment of the present invention, the cross-sectional shape of the terminal portion 9 is substantially rectangular, and the cross-sectional shape of the shaft core portion 8 is also substantially rectangular, which is a similar shape.

FIGS. 3B and 3C are cross-sectional views showing another example of the capacitor according to the first embodiment of the present invention. As shown in FIGS. The shape of the core 8 may be circular, hexagonal, or the like, and may be different from the cross-sectional shape of the terminal 9.

The cross-sectional shape of the terminal portion 9 is preferably a substantially square shape because of its excellent mountability. Is also good.

Further, the conductive film 4 formed on the surface of the substrate 1
As the material, at least one metal selected from Ag, Cu, Ni, and Zn can be used. Among them, Ag is particularly preferable because it has a high Q value.
When the conductive film 4 is formed by electroless plating,
It is preferable to use Cu.

As the exterior material 6, a material having an insulating property is used, and glass, an insulating resin or the like can be used. Among them, insulating resin is suitable for processing and low cost, and furthermore, thermosetting epoxy resin has strength,
It is particularly preferable because of its excellent moisture resistance.

The terminal electrodes 3 can improve the solderability at the time of mounting and protect the conductive film 4. As the terminal electrode 3, at least one or more materials selected from Ni, Sn, and solder can be used. Among them, an electrode in which Sn or solder is formed on a Ni layer is:
Particularly preferred is that the solderability and heat resistance are improved.

Then, the terminal electrode 3 is formed by using Ag as the conductive film 4 and further forming a Ni layer thereon and further forming Sn or solder.
By using, the Q value can be increased, and the solderability and heat resistance can be improved.

Further, the insulating separator 11 is made of an insulating material, for example, an insulating resin such as an epoxy resin, an acrylic resin, or a urethane resin, alumina, forster, barium titanate, strontium titanate, or the like. Insulating glass such as insulating ceramic, lead-based glass, and zinc-based glass are used.

Among these, the insulating photosensitive resin is
This is preferable because the patterning of the insulating separator 11 can be easily performed. Further, when the conductive film 4 is formed by electroless plating, among these insulating photosensitive resins, it is particularly preferable to use an insulating photosensitive resin to which electroless plating does not adhere.

Next, a method for manufacturing the capacitor of the present invention will be described.

First, the above-mentioned dielectric material is charged into a mold, molded, and then fired. Then, by shaving the center of the fired substantially rectangular parallelepiped base body 1 over the outer periphery, a shaft core portion 8 that is recessed over the outer periphery from the terminal portions 9 at both ends is formed.

Further, a mold is formed in advance so as to have the shaft core portion 8 which is recessed over the outer periphery than the terminal portions 9 at both ends.
The base material 1 may be formed by pressing a dielectric material with this mold and firing it. By forming in this manner, the step of shaving the base 1 can be eliminated.

Next, an insulating separator 11 is formed on the base 1. As a method for forming the insulating separator 11, a photosensitive resin is applied, exposed and developed, and patterned to have a gap 5 having a predetermined width. Alternatively, an insulating material may be directly applied to the base 1 so as to have the shape of the insulating separator 11.

The conductive film 4 may be formed by so-called dip coating in which the conductive film 4 is dipped and applied.
A film forming method such as a printing method, an electrodeposition method, a plating method, and an evaporation method can be used.

When a photosensitive resin of a type to which electroless plating does not adhere to the insulating separator 11 is used, Cu is used as the conductive film 4 and this is subjected to electroless plating to provide the insulating separator 11 with The Cu conductive film 4 is not formed, but the Cu conductive film 4 is formed only on the surface of the base 1, and the Cu conductive film 4 can be reliably separated by the insulating separator 11.

Further, the conductive film 4 is formed on the entire surface of the substrate 1 including the insulating separator 11 by various film forming methods, and then only the conductive film 4 on the surface of the insulating separator 11 is polished, laser trimmed, It may be removed by a method such as physical or chemical etching. Among them, laser trimming is preferable because of its high accuracy. Conventionally, when the gap 5 is formed in the conductive film 4 formed on the surface of the substrate 1 by laser trimming, the heat of the laser reaches the substrate 1 and the material of the substrate 1 is thermally denatured to deteriorate the characteristics. However, the provision of the insulating separator 11 can prevent the characteristics of the substrate 1 from deteriorating due to the heat of the laser.

Further, the exterior material 6 is filled with the above-mentioned insulating material so as to cover the insulating separator 11, the shaft core portion 8 and the conductive film 4 formed on the inclined portion 10.

Next, a terminal electrode 3 is formed on the conductive film 4 of the terminal portion 9 so as to cover the conductive film 4.

The capacitor 100 according to the first embodiment of the present invention has a substantially rectangular parallelepiped outer shape, and is excellent in mountability as a chip capacitor.

(Embodiment 2) FIG. 4 is a sectional view showing a capacitor according to Embodiment 2 of the present invention. In FIG. 4, reference numeral 110 denotes a capacitor, A denotes the height of the terminal portion 9, and B denotes the height of the shaft core portion 8.

In FIG. 4, the same components as those described in FIGS. 1 and 2 are denoted by the same reference numerals. Then, in the second embodiment, the components constituting the capacitor 110 are the same as those described in the first embodiment, and a detailed description will be omitted.

The base 1 of the capacitor 110 has the following configuration in order to maintain its mechanical strength and various characteristics.

That is, the dimensional ratio of the height A of the terminal portion 9 to the height B of the shaft core portion 8 is B / A = 0.5 to 0.85.
That is, the ratio of the height A of the terminal portion 9 to the height B of the shaft core portion 8 is in the range of A: B = 1: 0.5 to 0.85.

If this value is less than 0.5, the mechanical strength is insufficient and the quality cannot be maintained as a capacitor product.

When this value exceeds 0.85, the thickness of the exterior material 6 to be filled becomes insufficient, and the moisture resistance decreases.
The reliability becomes worse.

In the second embodiment, the capacitor 110 has been described with the base 1 having no inclined portion 10. However, the capacitor 110 may have the inclined portion 10 like the capacitor 100 described in the first embodiment. Needless to say, it's good.

Further, the method of manufacturing the capacitor according to the second embodiment is the same as that described in the first embodiment, and a description thereof will be omitted.

[0067]

EXAMPLES Next, examples of the capacitor of the present invention will be described.
The present invention will be described in detail with reference to comparative examples. The present invention is not limited at all by the following examples and the like.

Example 1 A predetermined amount of each of strontium titanate and calcium titanate powders as main components and bismuth oxide, titanium oxide and manganese oxide powders as additives was weighed by an electronic balance, and water was poured into a ball mill. And mixed for a predetermined time, and then dried to obtain a base powder.

Next, the base powder is granulated by a usual ceramic technique, a predetermined amount is put into a mold, and is compacted.
By firing at 1400 ° C. for 2 hours, a ceramic substrate 1 as shown in FIGS. 1 and 2 was obtained. The angle θ between the inclined portion 10 and the shaft core 8 is 95 degrees.

Then, a photosensitive resin of a type to which electroless plating does not adhere was applied to the surface of the ceramic substrate 1 which is a fired body of dielectric ceramics, and dried. Next, the photosensitive resin in the portion where the insulating separator 11 is provided is irradiated with ultraviolet rays to be photosensitive and cured, and the remaining uncured portion of the photosensitive resin is removed with an alkaline aqueous solution or the like. The insulating separator 11 was formed by patterning to have.

Thereafter, the surface treatment of the ceramic substrate 1 and the activation treatment of the electroless plating were performed, and the electroless plating was performed to form the conductive film 4 made of Cu. At this time, the Cu conductive film 4 is formed only on the surface of the base 1 without forming the Cu conductive film 4 by electroless plating on the insulating separator 11, and the Cu conductive film 4 is securely formed by the insulating separator 11. Had been separated.

Next, an exterior material 6 was formed by applying a thermosetting epoxy resin.

Further, electrolytic N
The i-plating was performed, and the Sn or solder electrolytic plating was further performed thereon to complete the chip-type ceramic capacitor of the first embodiment (the number of prototypes: n = 15).

(Comparative Example 1) A substrate 1 was once prepared by the same composition and forming method as in Example 1, and the substrate 1 was polished and the angle θ between the inclined portion 10 and the shaft core 8 was 85 degrees. A certain base 1 was obtained. The substrate 1 was processed in the same manner as in Example 1 to complete a chip-type ceramic capacitor of Comparative Example 1 (the number of prototypes: n = 15).

(Comparative Example 2) A substrate in which the angle θ formed between the inclined portion 10 and the shaft core portion 8 was 90 degrees by the same composition and forming method as in Example 1 except that only the mold in which the base powder was placed was changed. 1 was obtained. The substrate 1 was processed in the same manner as in Example 1 to complete a chip-type ceramic capacitor of Comparative Example 2 (the number of prototypes: n = 15).

(Example 2) A substrate in which the angle θ between the inclined portion 10 and the shaft core portion 8 is 150 degrees by the same composition and forming method as in Example 1 except that only the mold in which the base powder is put is changed. 1 was obtained. The substrate 1 was processed in the same manner as in Example 1 to complete the chip-type ceramic capacitor of Example 2 (the number of prototypes: n = 15).

(Comparative Example 3) A substrate in which the angle θ formed by the inclined portion 10 and the shaft core portion 8 was 160 degrees by the same composition and forming method as in Example 1 except that only the mold in which the base powder was placed was changed. 1 was obtained. The substrate 1 was processed in the same manner as in Example 1 to complete a chip-type ceramic capacitor of Comparative Example 3 (the number of prototypes: n = 15).

Next, the produced Examples 1 and 2 and Comparative Example 1
The following evaluations were performed on the chip-type ceramic capacitors of Nos. 1 to 3.

First, the presence or absence of bubbles in the exterior material 6 was checked. The evaluation method is to polish after cutting perpendicular to the inclined surface,
The cross section of the inclined portion was observed with a microscope (n = 5). Furthermore, the withstand voltage average value was measured. The withstand voltage (BDV) was measured by measuring the DC breakdown voltage in air using a Kikusui Electronics pressure gauge (n =
10), and the average value was calculated. The results are shown in (Table 1).

[0080]

[Table 1]

As is clear from Table 1, the inclined portion 10
If the angle θ between the shaft core portion 8 and the shaft core portion 8 is in the range of 90 to 150, the generation of bubbles can be suppressed, and the withstand voltage was also good.

Example 3 A ceramic substrate 1 shown in FIG. 4 was obtained by the same composition and forming method as in Example 1 except that only the mold in which the base powder was placed was changed. The height A of the terminal 9 (2.5 mm) and the height B of the shaft core 8
The ratio (1.3 mm) is A: B = 1: 0.52.

Then, patterning was performed so as to have a gap 5 having a predetermined width, thereby forming an insulating separator 11. Thereafter, the surface treatment of the ceramic substrate 1 and the activation treatment of the electroless plating were performed, and the electroless plating was performed to form the conductive film 4 made of Cu.

Next, an exterior material 6 was formed by applying a thermosetting epoxy resin.

Further, electrolytic N
The i-plating was performed, and the Sn or solder electrolytic plating was further performed thereon to complete the chip type ceramic capacitor of the third embodiment (the number of prototypes: n = 20).

(Comparative Example 4) The height A (2.5 mm) of the terminal portion 9 and the height A substrate 1 having a height B (1.0 mm) ratio of A: B = 1: 0.4 was obtained. The substrate 1 was processed in the same manner as in Example 3 to complete the chip-type ceramic capacitor of Comparative Example 4 (the number of prototypes: n = 20).

(Example 4) The height A (2.5 mm) of the terminal part 9 and the height of the shaft core part 8 were changed by the same composition and forming method as in Example 3 except that only the mold in which the base powder was put was changed. A substrate 1 having a height B (2.1 mm) ratio of A: B = 1: 0.84 was obtained. The substrate 1 was processed in the same manner as in Example 3 to complete the chip-type ceramic capacitor of Example 4 (the number of prototypes: n = 20).

(Comparative Example 5) The height A (2.5 mm) of the terminal portion 9 and the height of the shaft core portion 8 were changed by the same composition and forming method as in Example 3 except that only the mold in which the base powder was put was changed. A substrate 1 having a height B (2.3 mm) ratio of A: B = 1: 0.92 was obtained. The substrate 1 was processed in the same manner as in Example 3 to complete a chip-type ceramic capacitor of Comparative Example 5 (the number of prototypes: n = 20).

Next, the chip-type ceramic capacitors of Examples 3 and 4 and Comparative Examples 4 and 5 were evaluated as follows.

First, the withstand voltage average value was measured. The withstand voltage (BDV) was obtained by measuring the DC breakdown voltage in air using a Kikusui Electronics pressure gauge (n = 10), and calculating the average value. In addition, the short-circuited part was specified. Further, the flexural strength was measured. The flexural strength is JIS C642
9 Based on Annex 2, apply cream solder to the land of the printed circuit board, solder each chip type ceramic capacitor by reflow process, and use a predetermined jig.
A bending stress was applied to the chip-type ceramic capacitor together with the printed circuit board until the chip-type ceramic capacitor was broken (n = 10), and the average value was calculated.

The results are shown in (Table 2).

[0092]

[Table 2]

As is clear from Table 2, the ratio of the height A of the terminal portion 9 to the height B of the shaft core portion 8 is A: B = 1: 0.
Within the range of 5 to 0.85, the mechanical strength and the withstand voltage could be maintained.

As for the withstand voltage and the bending strength, the minimum value is described in addition to the average value. Furthermore, when B / A became large, the short-circuited part moved from the gap 5 to the surface of the exterior material 6.

Example 5 A ceramic substrate 1 as shown in FIGS. 1 and 2 was obtained by the same composition and forming method as in Example 1 except that only the mold in which the base powder was placed was changed.

Then, patterning was performed so as to have a gap 5 having a predetermined width, thereby forming an insulating separator 11. Thereafter, the surface treatment of the ceramic substrate 1 and the activation treatment of the electroless plating were performed, and the electroless plating was performed to form the conductive film 4 made of Cu.

Next, an exterior material 6 was formed by applying a thermosetting epoxy resin.

Further, the exposed conductive film 4 was plated with Ni, and further, electrolytic plating of Sn or solder was further performed thereon to complete the chip-type ceramic capacitor of Example 5 (the number of prototypes: n = 120).

Comparative Example 6 A ceramic substrate 1 as shown in FIG. 7 was obtained by the same composition and forming method as in Example 5 except that only the mold in which the base powder was placed was changed. Also,
The substrate 1 was processed in the same manner as in Example 5 to complete the chip-type ceramic capacitor of Comparative Example 6 (the number of prototypes: n).
= 120).

Note that the outer dimensions of Example 5 and Comparative Example 6
Table 3 summarizes the dimensions of the terminal portion 9 and the shaft core 8, and the angle θ between the inclined portion 10 and the shaft core 8.

[0101]

[Table 3]

In the chip type ceramic capacitor of the fifth embodiment, the cross-sectional shape of the terminal portion 9 and the cross-sectional shape of the shaft core portion 8 are both substantially rectangular, as shown in Table 3.
The dimensions are respectively terminal part 9 = width 3.2 mm × height 2.5
mm, shaft core 8 = 2.2 mm width x 1.5 mm height. The ratio of the height (2.5 mm) of the terminal portion 9 to the height (1.5 mm) of the shaft core portion 8 is 1: 0.6, the width of the terminal portion 9 (3.2 mm), and Width of part 8 (2.2 mm)
Is 1: 0.69, according to the invention from 1: 0.5 to
It satisfies the range of 0.85. Also, the inclined portion 10
Is inclined within 0.5 mm in width between the shaft core 8 (2.3 mm in length) and the terminal portions 9 (0.6 mm in length) at both ends thereof.

Next, the chip type ceramic capacitors of Example 5 and Comparative Example 6 were evaluated as follows.

First, the withstand voltage was measured. Withstand voltage (BD
V) The DC breakdown voltage was measured in air using a Kikusui Electronics pressure gauge (n = 10). Capacitance (Cap) and Q value were measured at 1 V using an LCR meter 4284A made by YHP.
The measurement was performed under a signal voltage of / 1 MHz (n = 10).

The results are shown in (Table 4).

[0106]

[Table 4]

Further, cream solder was applied to the lands of the printed circuit board, and each chip-type ceramic capacitor was soldered by a reflow process, and the connection state was evaluated (n = 100).

The results are shown in (Table 5).

[0109]

[Table 5]

As apparent from (Table 4) and (Table 5),
The capacitor of the present invention has good electric characteristics and excellent mountability.

[0111]

As described above, according to the present invention, it is possible to stably obtain a desired capacitance and to provide a highly reliable capacitor.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a capacitor according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a capacitor according to the first embodiment of the present invention.

3A is a cross-sectional view illustrating a capacitor according to the first embodiment of the present invention. FIG. 3B is a cross-sectional view illustrating another example of the capacitor according to the first embodiment of the present invention.

FIG. 4 is a sectional view showing a capacitor according to a second embodiment of the present invention.

FIG. 5 is a perspective view showing a conventional multilayer chip capacitor.

FIG. 6 is a sectional view of a conventional multilayer chip capacitor.

FIG. 7 is a sectional view of a conventional capacitor.

FIG. 8 is a sectional view of a conventional capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 Internal electrode 3 Terminal electrode 4 Conductive film 5 Gap 6 Exterior material 7 Concave part 8 Shaft core part 9 Terminal part 10 Inclined part 11 Insulating separator 20 Multilayer chip capacitor 30,40,100,110 capacitor

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Jiro Ota 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. F term (reference) 5E082 AA01 BB04 EE23

Claims (5)

[Claims] A base provided with terminal portions at both ends and a shaft core portion depressed over the outer periphery of the terminal portion; an insulating separator formed on the shaft core portion; And a conductive film formed by the insulating separator. 2. The capacitor according to claim 1, wherein said insulating separator is made of a photosensitive resin. 3. The capacitor according to claim 1, further comprising an exterior material covering the shaft core between the terminal portions at both ends. 4. The capacitor according to claim 3, wherein said exterior material and said terminal portions at both ends are substantially flush with each other. 5. The capacitor according to claim 1, wherein a terminal electrode is provided on the conductive film of the terminal portion.