JP3289564B2 - Thick film capacitors - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thick film capacitor used for electronic equipment and the like.

[0002]

2. Description of the Related Art A conventional technique will be described below.

[0003] In a conventional thick film capacitor, JP-A-5
As disclosed in 3-37856 discloses a thick-film capacitor provided on the upper surface of the substrate, and a protective coating film made of a first high temperature crystallized glass material, made of the second low-temperature crystallized glass material What is covered with a protective coat film
Have been.

[0004] The above-mentioned conventional technique will be described below with reference to the drawings.

FIG. 3 is a sectional view of a conventional thick film capacitor.

In FIG. 1, reference numeral 1 denotes a substrate made of ceramic or the like. Reference numeral 2 denotes a lower electrode provided on the upper surface of the substrate 1. Reference numeral 3 denotes a dielectric layer provided on the upper surface of the substrate 1 and partially provided so as to be electrically connected to the upper surface of the lower electrode 2. Reference numeral 4 denotes an upper electrode provided on the upper surface of the substrate 1 and partially provided so as to be electrically connected to the upper surface of the dielectric layer 3. Reference numeral 5 denotes a protective coating film provided on the upper surfaces of the upper electrode 4 and the lower electrode 2 so as to cover at least the dielectric layer 3.

[0007]

In the [0005] However the conventional configuration, during the firing of the upper electrode 4, the warp at the end portion of the dielectric layer 3 and the upper electrode 4 depending on the difference in shrinkage between the upper electrode 4
And peeling occur .

The present invention solves the above-mentioned conventional problems, and suppresses warpage and peeling that occur during firing of the upper electrode.
It is an object of the present invention to provide a thick film capacitor that can perform the following.

[0009]

In order to achieve the above object, a thick film capacitor according to the present invention is provided on an insulating substrate having first and second lower electrodes opposed to an upper surface, and on the upper surface of the insulating substrate. A dielectric layer provided so as to be electrically connected to a part of the upper surface of the first lower electrode, and a part provided on an upper surface of the second lower electrode and having a part formed on the upper surface of the dielectric layer Provided to be electrically connected to
Printed metal paste containing a small amount of glass components
An upper electrode formed by baking, the upper surface of the upper electrode
And a glass layer provided so as to overlap only with the glass layer.

[0010]

According to the above construction, the electrode is provided on the upper surface of the second lower electrode.
And partially electrically connected to the top surface of the dielectric layer
Gold that contains a small amount of glass components
Top surface of upper electrode formed by printing and firing metal paste
Since the glass layer is provided so as to overlap only
The glass component in the glass layer is
Fused with a small amount of glass components contained in the
A porous dielectric layer is formed through the cavities during sintering of the upper electrode.
Will be supplied to the upper surface, thereby, the upper electrode
Baking of the upper electrode to improve the adhesion state with the dielectric layer
Sometimes caused by the difference in shrinkage between the dielectric layer and the upper electrode
Warpage and peeling can be reliably suppressed.

[0011]

Embodiment 1 Hereinafter, a thick film capacitor according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1A is a perspective view of a thick film capacitor according to an embodiment of the present invention, and FIG. 1B is a sectional view taken along the line AA of FIG. 1A.

In FIG. 1, reference numeral 11 denotes an insulating substrate made of ceramic or the like. 12a and 12b are insulating substrates 1 respectively.
First and second lower electrodes provided to face the upper surface of the first electrode. Reference numeral 13 denotes a dielectric layer provided on the upper surface of the insulating substrate 11 and partially provided so as to be electrically connected to the upper surface of the first lower electrode 12a. 14 is the second
Is an upper electrode provided on the upper surface of the lower electrode 12b and partially provided so as to be electrically connected to the dielectric layer 13. 15 is at least the first lower electrode 12a side
Is a glass layer provided on the upper surface of the end portion of the upper electrode 14 located at the position shown in FIG.

A method of manufacturing the thick film capacitor having the above-described structure will be described below.

First, an insulating substrate 11 made of ceramic or the like is used.
A metal paste containing a trace amount of glass component is printed and dried on the upper surface of the first lower electrode 12a so as to face each other.
And a second lower electrode 12b is formed.

Next, a dielectric paste is printed and dried on the upper surface of the insulating substrate 11 so as to partially overlap the upper surface of the first lower electrode 12a to form a dielectric layer 13.

Next, the first lower electrode 12a extends from the upper surface of the dielectric layer 13 to a part of the upper surface of the second lower electrode 12b.
Metal paste with the same composition as
Is printed and dried, and the upper electrode 14
To form

Next, at least the first lower electrode 12a side
The glass layer is formed by printing and drying a glass paste on the upper surface of the end of the upper electrode 14 located at the position shown in FIG.

Finally, the product formed in the preceding step is fired to produce the thick film capacitor of the present invention.

One embodiment of the present invention configured as described above
The thick film capacitor in the above is provided on the first lower electrode 12a side.
A glass layer 15 is formed on the upper surface of the end of the upper electrode 14 located.
The glass component in the glass layer 15
Is contained in the metal paste forming the upper electrode 14.
At the time of sintering of upper electrode 14 by fusing with a small amount of glass component
Supplied to the upper surface of the porous dielectric layer 13 through the holes of
As a result, the upper electrode 14 and the dielectric layer
Baking of the upper electrode 14 to improve the state of adhesion to the upper electrode 14
Sometimes, the difference in shrinkage between the dielectric layer 13 and the upper electrode 14 causes
Warpage and peeling occurring due to the above can be reliably suppressed.

Also, the second lower electrode 12b and the dielectric layer 1
When the width of the upper electrode 16 corresponding to the upper surface of the portion in contact with 3 is made smaller than the width of the upper electrode 14 positioned on the upper surface of the dielectric layer 13 , the absolute amount of the metal paste required to form the upper electrode 14 is reduced. Therefore, it is possible to reduce the bleeding of the paste of the upper electrode 14 generated between the first lower electrode 12a and the portion where the second lower electrode 12b and the dielectric layer 13 are in contact with each other. This allows the paste
Short circuit between the upper electrode 14 first lower electrode 12a by bleeding also can cause reduced.

FIG. 2 is a diagram showing the relationship between the capacitance value of the thick film capacitor of the present invention and the possible frequency.

This means that the target capacity value (target value) is 10
When 0 pF is set, the thick film capacitor 10 having the same dimensional conditions is used.
About 00 pieces, the glass layer of the present invention was formed,
It is a result of examining the relationship between the capacitance value and the frequency distribution of the conventional case having no glass layer. LC for measuring capacitance value
Using an R meter, the thick film capacitor of the present invention and the conventional thick film capacitor are used.
The measurement was performed by applying a probe to terminal electrodes at both ends of each of the membrane capacitors .

The conventional thick film capacitor has a target value of 10
It is distributed in the range of 70 to 90 pF apart from 0 pF.

This is because, even under the same dimensional conditions, the area of the upper electrode facing the first lower electrode is reduced due to warpage or peeling, so that the distribution is in a range of values apart from the target value.

In contrast, the thick film capacitor provided with the glass layer of the present invention is distributed around the target value of 100 pF, and the capacitance value range close to the target value is ± 20%.
(According to the symbol M of the capacitance tolerance of JIS5101). Therefore, a large number of thick film capacitors having a capacitance value close to the target value can be obtained.

[0027] Note that in one embodiment of the present invention, in order to narrow the upper electrode 16 has been narrowed upper electrode 14 located on the upper surface of the second lower electrode 12b, the upper electrode 16
Make the corresponding part narrower or use the upper electrode
Even if only the portion corresponding to 16 is narrowed ,
The same effect as that of the first embodiment can be obtained.

In one embodiment of the present invention, the area of the glass layer 15 is reduced by the first lower electrode 12a and the upper electrode 14a.
DOO but has substantially the same size as the area opposed to this Gala
Layer 15 is located at least on the first lower electrode 12a side.
It is sufficient if it is formed on the upper surface of the end of the upper electrode 14 to be formed.
But, the glass layer 15 forms formed in the same area as the upper electrode 14
Even in this case, the same effect as that of the embodiment of the present invention can be obtained.

[0029]

As described above, the thick film capacitor of the present invention is
Is provided on the upper surface of the second lower electrode and partially
Provided to be electrically connected to the upper surface of the dielectric layer,
Printing and firing of metal paste containing a small amount of glass components
Glass so that it only overlaps the top surface of the upper electrode
The glass layer in this glass layer
The fine particles contained in the metal paste forming the upper electrode
Vacancy during sintering of the upper electrode fused with the amount of glass component
To the top surface of the porous dielectric layer through
As a result, the state of adhesion between the upper electrode and the dielectric layer is
In order to improve the dielectric layer and the upper electrode during firing of the upper electrode,
Warpage and peeling caused by the difference in shrinkage rate
It has the effect that it can be obtained.

[Brief description of the drawings]

FIG. 1A is a perspective view of a thick film capacitor according to an embodiment of the present invention . FIG. 1B is a cross-sectional view taken along a line AA in FIG.

FIG. 2 is a diagram showing a capacitance value distribution comparing a thick film capacitor of the present invention with a conventional thick film capacitor.

FIG. 3 is a cross-sectional view of a conventional thick film capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Insulating substrate 12a 1st lower electrode 12b 2nd lower electrode 13 Dielectric layer 14 Upper electrode 15 Glass layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-53-4844 (JP, A) JP-A-50-110061 (JP, A) JP-A-49-114762 (JP, A) JP-A 52-1984 29953 (JP, A) JP-A-50-32466 (JP, A) JP-A-6-77082 (JP, A) JP-A-51-115035 (JP, U) (58) Fields investigated (Int. ⁷ , DB name) H01G 4/00-4/42

Claims (1)

(57) [Claims] 1. An insulating substrate having first and second lower electrodes opposed to an upper surface, and a portion provided on the upper surface of the insulating substrate and partially electrically connected to the upper surface of the first lower electrode.
A dielectric layer provided so as to be, the second part together is provided on the upper surface of the lower electrode is provided so as to be connected upper and electrically of the dielectric layer, and trace amounts of gas
A thick film capacitor comprising: an upper electrode containing a lath component; and a glass layer provided so as to overlap only the upper surface of the upper electrode.