JPH03230510A - Laminated ceramic capacitor and manufacture thereof - Google Patents

Abstract

PURPOSE:To effectively obtain a laminated capacitor having high dielectric breakdown strength, by forming an insulating layer containing polyimide resin on the exposed part of an inner electrode plate on the side end surface and ceramics in the vicinity of said part. CONSTITUTION:A laminated ceramic capacitor is constituted by alternately stacking ceramic films 2 and inner electrode plates 22. An insulating layer containing polyimide resin having repetition unit expressed by formula I is formed on the exposed part of the inner electrode 22 on the side end surface and ceramics in the vicinity of said part. In the formula I, X and Y are radicals selected out of a group composed of phenyl group, biphenyl group, and polyphenyl group. Thereby the laminated ceramic capacitor can be provided with high dielectric breakdown strength, and also efficient production is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to ceramic laminate elements, particularly to laminate ceramic capacitors and methods for manufacturing these elements.

[Conventional technology]

Conventionally, a ceramic laminate element in which ceramic films or thin plates and internal electrodes are alternately laminated, such as a laminated ceramic capacitor, is typically manufactured by the following method.

First, raw material compositions are mixed and calcined, a suitable binder and solvent are mixed with this calcined powder, and a thin film is formed using this mixture by a doctor blade method. Metal electrodes are printed on this thin film and laminated.

A plurality of metal electrode plates in this laminate are connected to external electrodes every other time, so that one system is positive and the other system is negative.

In this manufacturing method, as shown in Figure 1, the area of the overlapping portion of the positive and negative electrode plates must be smaller than the total cross-sectional area, and therefore, there is a portion where the electrode plates do not overlap in the peripheral area. .

Since the capacitance of a capacitor is proportional to the electrode area, the above-mentioned capacitor cannot utilize the entire cross-sectional area of the ceramic thin film, which is an obstacle to increasing the size and capacity of the capacitor. Also, depending on the type of ceramic, relatively large distortions may occur when voltage is applied. This may cause failures such as destruction of the ceramics or peeling of internal electrodes. Furthermore, in order to manufacture such a multilayer capacitor, it is necessary to increase the printing accuracy of the internal electrodes and to increase the lamination position t+'i of each green saw during lamination, which becomes an obstacle to improving productivity. It has become.

As a method to eliminate the above-mentioned deficiencies, there is an example of an electrician effect element, 1+f 155
7! IS': Using the electrophoresis method described in the publication, the entire surface or - of the electrode exposed on the side 1' of A:i-
A method for manufacturing an electrical effect element is disclosed, which is characterized in that an inorganic insulating layer is formed every other layer. When such a manufacturing method is used, the above-mentioned drawbacks are eliminated. However, this method is not economical because it requires high temperatures to bake the 5rrc insulating layer (which is usually glassy), and since the inorganic insulating layer has good compatibility with the ceramic body, It is said that the distance between the layers must be 100 microns or more so that the insulating layers adhered to each electrode exposed on the side end surface are not continuous with each other.
The drawback is that it is only possible to make capacitors with high capacitance below a micron.

[Invention or problem to be solved]

In recent years, multilayer ceramic capacitors, which are small and have large capacitance, have become increasingly popular. Therefore, while searching for ceramics with a high dielectric constant, efforts are being made to reduce the thickness of the ceramic layer, and some prototypes have been produced with a layer thickness of 10 microns or less. .

In order to efficiently produce multilayer capacitors having such thin layers, it is necessary to develop a new electrode insulation method that does not have the disadvantages mentioned in the "Prior Art" section above.

[Means to solve the problem]

The present inventors have previously proposed an insulating method for end-layer electrical elements, in which polyamic acid is deposited on the exposed end of the element of the internal electrode by electrophoresis to form 11!2 layers, and then heated. previously applied for a method of imidizing the polyamic acid resin of the coating layer and forming an insulating layer with the obtained polyimide resin (Japanese Patent Application Hei 1-171854). The thickness of one layer of the laminate was increased to 100 mm instead of the insulation using organic materials, which was known as a laminate.
It was also revolutionary in that it could be made smaller than microns. Furthermore, as an improvement to this method, a method was proposed in which an insulating filler was deposited at the same time as polyamic acid was deposited on the exposed end portion of the element of the internal electrode (Japanese Patent Application No. 1-294900).

The present inventors have discovered that the above method can also be applied to the above-described multilayer ceraminotas capacitor, and have completed the present invention.

That is, the present invention provides a multilayer ceramic capacitor in which (11) ceramic films or thin plates and internal electrode plates are alternately laminated, wherein the end surfaces of the internal electrode plates are exposed at the side end surfaces of the multilayer ceramic capacitor. , the general formula (1
) (wherein, X is a phenyl group: a biphenyl group, and at least one of a phenyl group and a biphenyl group, or 0, C01S,
SO,, CI(2, C(CH3)2 and c(cpa)
is a tetravalent group selected from the group consisting of polyphenyl groups bonded by at least one of z, Y is a phenyl group, a biphenyl group; at least one of a phenyl group and a biphenyl group, or C (C
A polyphenyl group bonded by at least one of H, )2 and C(CF3)2; a divalent group selected from the group consisting of an alkylene group and a xylylene group). A multilayer ceramic capacitor characterized in that an insulating layer containing a polyimide resin is formed, (2) a multilayer ceramic capacitor in which an insulating layer made of a polyimide resin containing an insulating filler is formed; 3) A ceramic laminate in which ceramic films or thin plates and internal electrode plates are alternately laminated, with the end surfaces of the internal electrode plates exposed on the side end surfaces of the ceramic laminate,
General formula (II) (wherein,
o, s, so2, CIl□, C(C1l,)2 and C(CF])2 are tetravalent stores selected from 11t consisting of a polyphenyl method bonded by one type, )' is a phenyl group, a hypohenyl group, a phenyl group, and a small amount of a hypohenyl group (and C1 type or 0, co, s, s
o2, C12, C(CIl,)2 and C(CF,)2: m from the group consisting of a polyphenyl group, alkylene, ll, and quinorylene group, both of which are bonded by l +=1 : The repeating unit represented by (fdli) was immersed in an electrophoresis bath containing a film-forming agent obtained by neutralizing the carboxyl groups of polyamic acid resin (f) with a base and diluting it with water. , conduct an electrical motion using the internal electrode plate of the ceramic laminate as an anode to deposit the polyamic acid only on the exposed portion of the internal electrode plate on the side end surface of the ceramic laminate and in the vicinity thereof, thereby forming a coating layer. formed, and then heat-treated to imidize the polyamic acid resin of the coating layer to contain a polyimide resin having a repeating unit represented by the general formula (T) (wherein X and Y are as described above). (4) forming an insulating layer on the side end surface of a ceramic laminate in which ceramic films or thin plates and internal electrode plates are alternately laminated; The ceramic laminate with the end face of the internal electrode plate exposed is formed by the general formula (II) (wherein,
SO□, C112, C(CH3)2 and C(CF3)
2 is a tetravalent group selected from the group consisting of polyphenyl groups bonded by at least one of 2, and Y is a phenyl group: at least one of a phenyl group, a phenyl group, and a hyphenyl group, or 0, CO1S, SO2, CH2, C (C
A repeating unit represented by a small number of H3)2 and C(CF3)2 (both polyphenyl groups bonded by one type: a divalent group selected from the group consisting of an alkylene group and a quinrylene group) In an electrophoresis bath for film formation obtained by neutralizing the carboxyl groups of the polyamic acid resin with a base and diluting it with water in a composition consisting of a polyamic acid resin having the following properties and an insulating filler dispersed in the resin. The polyamic acid and the polyamic acid are immersed in the ceramic laminate and subjected to electric motion using the internal electrode plate of the ceramic laminate as an anode, so that only the exposed portion of the internal electrode plate on the side end surface of the ceramic laminate and the vicinity thereof are exposed to the polyamic acid and the polyamic acid. The insulating filler coated with A method for manufacturing a multilayer ceramic capacitor, characterized by forming an insulating layer made of a polyimide resin having a repeating unit represented by the following formula and an insulating filler.

Part of the polyamic acid resin used in the production method of the present invention may be imidized in advance.

In the polyimide resin having a repeating unit represented by the above general formula (I) and the polyamic acid resin having a repeating unit represented by the general formula (II), the following are specific examples of X, and specific examples of Y: There is a next life.

the above Repeating unit represented by general formula (I) Polyimide with Ceramic laminate base made of resin [X-sided from the viewpoint of stealth to O and heat resistance, Y? It is particularly preferable that

The general formula (I) used in the production method of the present invention
The boamic acid resin having the repeating unit represented by I) is a tetracarphonic acid anhydride having the general formula (III) (wherein, X is as described above) and the general formula (IV) 14□N-Y-NH7 (IV) (wherein Y is as described above) can be obtained by addition reaction with diamines.

Examples of the above-mentioned tetracarphonic anhydrides include pyromellitic dianhydride, 3.3'-, 4.4°-benzophenonetetracarphonic dianhydride, 2.2°, 3.
3hensiphenotetracarphonic dianhydride, 3°3'
, 4.4-biphenyltetracarboxylic dianhydride,
2.2°, 3.3'-biphenyltetracarboxylic dianhydride, 2.2-his(3,4-dicarboxyphenyl)brobannianhydride, 2.2-bis(2,3-)carboxydiphenyl ) propanianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, bis(3,4-
dicarboxyphenyl) sulfone dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride,
Bis(2,3-dicarboxylphenyl)methanidianhydride, bis(3,4-dicarboxylphenyl)methanidianhydride, 2.3.6.7-naphthalenetetracarboxylic dianhydride, 1.4.5. 8-naphthalenetetracarboxylic dianhydride, 1,2゜5.6-naphthalenetetracarboxylic dianhydride, 1.2.3.4-hensentetracarboxylic dianhydride, 3.4. 9.10-perylenetetracarphonic dianhydride, 2.3.6.7-anthracenetetracarphonic dianhydride, 1.2.7.8-phenanthorente[·racarphonic dianhydride, etc. These are listed as preferred.

Among these, particularly preferred tetracarphonic dianhydrides are pyromerino 1-acid dianhydride, 3.3゛, ~1.・
1 benzoenonetetracarphonoic acid 2j low water 1 course, 3.3
', 4,4-hisphenyltetracarboxylic dianhydride, and bis(3,4-nocalphoquinophenyl)ether dianhydride.

” - diamines include 3.3°-noaminohenzophenono, 1.3-his(3-aminophenoquino)hensen, 4.4'-his(3-aminophenoquino)hyphenyl, 2 .2-His[(3-aminophenoxy)phenyl]phenyl]propane, 2.2-His[・1-(
3aminophenogino)phenyl) -1,1,1,3,
3,3 hexafluoropropane, his[1-(3-aminophenoxy)phenyl]sulfite, his[tho(3-aminophenoquine)phenyl]ketone, bis[4(3-aminophenoquino)phenyl]sulfone, etc. These diamines can be used alone or in combination of two or more types.

The reaction between the above-mentioned tetracarphonic anhydride and diamine is usually carried out in an organic solvent. Examples of the organic solvent include N-methyl-2-pyrrolidone and N.

N-thumedylacetami[·, N, N-thmethylformamide, 1,3-thmethyl-2-imidazolidinone, N
, N-noethylacetamito, N,N-trimethylmethoquinoacetamyl', trimethylsulfokite, birinone,)
/tyrsulfone, hexamethylphosphorus l~, tetramethylurea, N-methylcaprolactam, tetrahydrofuran, l,2-nomethogynoethane, his(2-methogynoethyl)ether, 1,2-his(2-methoxynoethquino)ethane, bis( Examples include 2-(2-methoxynoethquino)ethyl]ether, etc. These organic solvents may be used alone or in combination of two or more.

The reaction temperature is usually -20°C or more and 200°C or less, preferably -10°C or more and 50°C or less, more preferably 0.
The temperature is about room temperature, which is above °C.

The reaction pressure is not particularly limited, and the reaction can be carried out at normal pressure.

Reaction times may vary depending on the type of solvent, reaction temperature, and diamine or dianhydride used, but are usually 2 to 30 minutes to allow the reaction to occur long enough to complete the formation of the polyamic acid.
40 hours, preferably 4 to 21 hours is sufficient.

The polyamic acid solution obtained by
It is a solution containing about 40 Bkg6, and has a logarithmic viscosity of 0. 5 to 4 di/g (35°C, temperature 0.5
g/me, N.

It is preferable to use a polyimide having a value of about 11 (Ilt11) determined with N-dimethylacetamide because it is excellent in water solubility, which will be described later, and in the physical properties of the polyimide film after heat treatment.

In the present invention, an insulating filler can also be added to the polyamic acid obtained as described above. The addition method may be any method such as roll kneading or hole milling as long as the insulating filler is sufficiently dispersed in the polyamic acid. The amount of insulating filler added is 2
~70 capacity or about 96 is preferable. If the amount added is too small, the effect of the addition will not be achieved, and if it is too large, the insulating filler will precipitate in the final electrophoresis bath, which is not preferable.

The insulating filler used in the present invention has a resistivity of 105Ω・c
It may be an inorganic compound or an organic compound as long as it exhibits an electrical resistance of about m or more. Inorganic compounds used as such insulating fillers include beryllium, magnesium, calcium, aluminum, boron, silicon, scannoum, yttrium, lanthanum,
Titanium, zirconium, hafnium and rare earth oxides and composite oxides, aluminum, boron, silicon, titanium,
Examples include nitrides and oxynitrides such as zirconium and hafnium, and carbides such as silicon carbide. In addition, the organic compound must be one that does not dissolve in an electric bath, and examples of such compounds include soricone resin, fluorine resins such as Teflon, phenolic resin, furan resin, evoquinone resin, and acrylic resin. Examples include resin.

In the present invention, the shape of the insulating filler is arbitrary regardless of whether it is particulate or fibrous, but its dimensions are determined in relation to the required thickness of the insulating layer. In other words, it is necessary that the maximum diameter of the insulating filler is smaller than the minimum thickness of the insulating layer film.

Furthermore, considering that industrially it is important to maintain a good T dispersion state in an electrophoresis bath, the 1σ deviation is such that the average diameter of the insulating filler is 20 microns or less, preferably 10 microns or less. That's 1! It's sad.

In the production method of the present invention, whether or not an insulating filler is dispersed in a polyamide acid solution,
Represented by the general formula (■) above, repeat! ii position f
In the presence of water, the polyatoic acid + S + fat dissociates into active COO++ or C0D- ions and becomes water-soluble or stably colloids by adding a base, such as an amine or an alkali ion. - It can be dispersed, and it can be precipitated on the internal electrode plate exposed on the side of the ceramic dipping layer body, which is the anode, by electricity and water movement, and can be made insolubilized.

The above bases include ammonia: dialkylamine,
Secondary amines such as jetanolamine and morpholine Tertiary amines such as triethylamine, tributylamine, triethanolamine, triisopropazuramine, trimethylethanolamine, trimethylisopropazuramine, noethylethanolamine, and dimethylhenylamine Inorganic bases such as amines such as caustic soda and caustic potash are used, and tertiary amines are particularly preferred from the viewpoint of stability after dilution with water and the properties of the resulting film.

The amount of base necessary to impart water dilutability is 30 to 110 moles based on the calhoquine equivalent of the polyamic acid to be neutralized.
6 is common, and 40 to 100 mol 06 is particularly preferred. By neutralizing in this manner, the polyamic acid becomes completely water-soluble or partially water-soluble, becoming suspended and dilutable with water.

By diluting the above neutralized composition with water, a suspension of electrolytic, dynamically treated or reprocessed polyamic acid and/or an insulating filler coated with said polyamic acid is obtained. It is possible to use an electric or water-moving bath for film formation.

The coating layer composed of the polyamic acid resin or the polyamic acid resin and the insulating filler precipitated in this way has a repeating unit represented by the general formula (1) (wherein X is as described above) by heat treatment. It is converted into an insulating layer made of polyimide resin or polyimide resin and filler.

The polyimide resin obtained as described above, or the insulating layer made of the polyimide resin and an insulating filler, both have excellent dielectric strength and excellent adhesion to metal.

The structure of the multilayer ceramic capacitor according to the present invention is such that ceramic films or thin plates and internal electrode plates are alternately laminated, and the internal electrode plate is made of ceramic.・The Nox film or thin plate is present on both the upper and lower surfaces, and its end face is exposed on the side end face of the multilayer capacitor, and the end face of each internal electrode plate is exposed layer by layer when external electrodes are attached. It is insulated with the aforementioned polyimide resin-containing insulating layer so as to have separate positive and negative polarities. To install such a multilayer capacitor in a circuit, connect N+ to the above external electrode.
It is also possible to directly attach a small amount of plating such as Sn, etc.
It is also possible to attach a leet wire to the external electrode and connect it to the line using a 1-1 wire.

Further, if necessary, it may be sealed with a phenol resin or the like.

All ceramics used in ceramic capacitors can be used in the multilayer ceramic capacitor of the present invention. Give an example of these: Pb(Zn, Nb)0
3, Pb(Fe, W)0, Pb(Fe, Nb)03
, Pb(Mg, Nb)02, Pb(N+, W)02,
Pb(Mg, W)03, PbTIOs, Pb(Zr
.

TI)03, Pb(L+, Fe, W)Os, (Pb+-
xLax) (Zr, Tit-y) lead-based perogeskite compounds such as Oz, lead-based compounds such as Pb5GezO+ +,
BaTi0a, Ba(Ti, 5n)03, (Ba,
Sr, Ca)T+Ch, (Ba, Ca) (Zr,
Ti)Oz, (Ba, Sr, Ca)(Zr,
Barium yarn perovskite compounds such as Ti)Os, 5
These include strontium-based perovskite compounds such as rTiOz, calcium-based perovskite compounds such as CaTiO3 and CaZrOs, and layered compounds such as BIa-IJ+2. Alternatively, a mixture thereof may be used. Furthermore, the ceramic sheet of the present invention also includes natural and/or artificial mica.

Examples of the material for the internal electrode plate include conductive metal materials such as silver, palladium, gold, carbon dioxide, copper, zinc, and alloys thereof.

Note that the laminate referred to in the present invention is not limited to those made by the so-called Green Note method, but also includes sintered thin plates bonded together in length, and ceramics made by CVD or PVD. Of course, those in which thin films of wax and electrodes are alternately stacked on top of each other are also contemplated.

〔Example〕

The present invention will be explained in more detail with reference to Examples below. ′
! However, the present invention is not limited to these embodiments.

Example 1 In a reaction vessel equipped with a stirrer, a reflux condenser and a nitrogen inlet tube, 53.0 g of 3,3'-diaminohensiphenone (0
, 25 mol) to N,N-trimethylacetamide 240
ml was dissolved. 3.3', 4.4°-
Benzophenone tetracarphonic acid dianhydride Th78.6g
(0,244 mol) of powder was added and heated at 10°C for 24 hours.
Stir for a while and pour out the polyamic acid solution. The logarithmic viscosity of the obtained polyamic acid was 0.6 dl/g. In this polyamic acid solution, 23.9% of trimethylethanolamine was added.
Gradually add g (equivalent to Calhokituru 55 mol 06),
After stirring at room temperature for 20 minutes, 905.3 g of water was gradually added at room temperature while stirring and diluted with water to prepare an aqueous polyamic acid solution (resin concentration: 10 ffi 06 ).

In addition, a laminate (50 layers laminated with a - layer thickness of about 50 μm, ceramic composition is Pb (Zn, Nb) 0.-Pb (Mg
, Nb)03BaTiOa system, relative permittivity is approximately 9.000
．． The internal electrode is mainly made of an alloy of silver and palladium)
For the sample, one end face had metal electrodes exposed on every other layer, and the other end face had all metal electrodes exposed. - I solder a silver electrode to the exposed metal electrode on every other layer, and connected a single wire with solder. The aqueous solution was placed in a plastic tank to form an electric 6 water bath for film formation, and the surface dipping layer to be coated was used as an anode, and the infiltration end-1 wire was connected to the anode. 60V 4
Electrophoresis was performed by applying a voltage for seconds. After that, take out the laminate and wash it with water! 2 hours at 50°C, 2 hours at 280°C
Dry imidization was performed by heat treatment for several hours. Next, cut the laminate in the middle, and place KJ on the side where the resin insulation film is attached.
The electrode was applied and a line was attached. By performing the same operation, a laminate having insulating layers on the left and right sides of each electrode wedge was obtained. It was confirmed that the thickness of this insulating layer was approximately 50 microns and the dielectric strength was 500 V or more.

Example 2 In a reaction vessel equipped with a stirrer, a 5AIRE condenser and a nitrogen inlet tube, 3.3'-diaminohensiphenone 53.0
g (0.25 mol) of N,N-dimethylacetamide 2
It was dissolved in 40ml. 3.3', 4.4 to this solution
'-hensiphenotetracarphonic dianhydride 78.6
g (0,244 mol) of powder was added and heated at ]0°C to 2
The mixture was stirred for 4 hours to obtain a polyamic acid solution. Add 6 pieces of alumina powder (trade name, AKP-30, manufactured by Sumitomo Chemical) to this solution.
20g was added and kneaded using three rolls to prepare an aqueous alumina-dispersed polyamic acid solution. Add 21.7 g of dimethylethanolamine to this varnish (jt50 per calhoquine)
Mol96)? After adding the excess and stirring at room temperature for 20 minutes, 905.3 g of water was gradually added at room temperature while stirring to dilute with water to prepare a polyamic acid suspension containing alumina powder.

Further, as for the sample of the laminate, the same one as in Example 1 was used, and a silver electrode was baked on the exposed side of the metal electrode every other layer, and a rieet wire was connected with solder. The suspension was placed in a plastic tank to serve as an electrophoresis bath for film formation, and the laminate to be coated was infiltrated as an anode, and a lead wire was connected to the anode. Electrophoresis was performed by applying a voltage of 20V for 5 seconds. Thereafter, the laminate was taken out, washed with an aqueous solution containing 20% by weight of N,N-dimethylacetamide, and then heated at 150°C for 2 hours and at 280°C for 2 hours to form a dry imitation 1. . Next, cut the laminate in the middle and apply a silver electrode to the side where the imide resin insulating film is attached.・I added a line. By performing the same operation, a laminate having insulating layers on the left and right sides of each electrode was obtained. The thickness of the second insulating layer was about 50 microns.

When the dielectric strength of the laminate thus obtained was determined by J1j, it was found to be 500 V or more.

Example 3 In a container equipped with a stirrer, a reflux condenser, and a nitrogen inlet tube, 2,2-his(,1-(3-aminophenogino)phenyl]propane + 1.(]8 g, 0.1 mole) and \, \
- Loaded with 200 ml of ``Tumethylace I amyl'' and
``Cooled to near Cf1 and heated under nitrogen atmosphere.
A powder of 21.8 g (0° 1 mole) of 1-acid dihydride was stirred at +Jl+ for 2 hours at ()°C. Next, the bipod solution was brought to room temperature and stirred for about 20 hours under a nitrogen atmosphere. The logarithmic viscosity of the polyamic acid thus obtained was 1.5 dl,'g. Into this polyamic acid solution (20.2 g of ethylamine (per carphoquinol), 100 mol of U'L (,) was gradually added and stirred at room temperature for 1 hour, and then 973 g of water was gradually added with stirring. The mixture was diluted to prepare an aqueous polyamic acid solution (resin concentration: 5:06 by weight).

A sample of a laminate was prepared in the same manner as in Example 1, and an insulating layer was provided in the same manner as in Example 1 using this sample and the above polyamic acid aqueous solution. This insulating layer has a thickness of 50μ and 5
It had a dielectric strength of 00V or more.

Example 4 In a container equipped with a stirrer, a reflux condenser and a nitrogen inlet tube, 2
．． 2-His(4-(3-aminophenoxo)phenyl)
Add propane, Og (0.1 mol) and ~219.6 g of N,N-dimethylacedo, and add 3-31. L 4-Hensephenonetetracarphonic dianhydride: 31.6 g (0,098 mol) was added as a dry solid in small portions while being careful not to increase the temperature of the mixture, and the mixture was reacted at room temperature for 23 hours. . The logarithmic viscosity of the polyatoic acid thus obtained was 0.70 dl/g. 14.6 g of triethanolamine (
50 moles of carfoquinol equivalent (96) was gradually added, stirred at 10°C for 2 hours, and 117.2 g of water was gradually diluted with stirring to prepare a poly(amic acid)-acid aqueous solution (resin concentration). 15 weight 06).

A sample of a laminate was prepared in the same manner as in Example 1, and an insulating layer was provided in the same manner as in Example 1 using this sample and the above polyamic acid aqueous solution. This insulating layer had a thickness of 50 g and a dielectric strength of 500 V or more.

Example 5 Noriyoku powder (average particle size 0.5μ) was used instead of alumina powder.
An experiment was conducted in exactly the same manner as in Example 2 except that m) was used. The dielectric breakdown voltage of the sample was 500V or more.

Example 6 Silicon nitride powder (average particle size 0.8
The experiment was conducted in exactly the same manner as in Example 2, except that .mu.m) was used. The dielectric breakdown voltage of the sample was 50OVv, above
child.

Example 7 Titania powder (average particle size 0.8
The experiment was conducted in exactly the same manner as in Example 2, except that .mu.m) was used. The dielectric breakdown voltage of the sample was 500V or more.

〔Effect of the invention〕

As is clear from the above examples, the multilayer ceramic capacitor according to the present invention has high dielectric strength, and can be manufactured more easily and efficiently than the conventional method, making it possible to produce a highly reliable multilayer ceramic capacitor at a low cost. It can be manufactured.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional perspective view of a conventional multilayer ceramic capacitor currently on the market. In Figure 1, ■ is dielectric ceramic, ■ is internal electrode,
■ indicates an external electrode. FIG. 2(a) is a cross-sectional perspective view of a multilayer ceramic capacitor according to the present invention. In FIG. 2(a), ■ is the dielectric ceramic, ■ is the internal electrode, 0 is the polyimide-containing insulating layer, ■ is the A side, and [
phase] indicates the B side. In this figure, the external electrodes on both sides of A and B are omitted. Further, FIG. 2+1)l is a cross-sectional view of the multilayer ceramic capacitor of the present invention. In FIG. 2(b), @ indicates the dielectric ceramic, @ indicates the internal electrode, ■ indicates the polyimide-containing insulating surface, ■ indicates the external electrode, ■ indicates the A side, and [phase] indicates the B side. Further, the internal electrodes extending from both sides of A and B, which reach the side surfaces every other layer, are all covered with an insulating layer and insulated.

Claims (4)

[Claims] (1) A multilayer ceramic capacitor in which ceramic films or thin plates and internal electrode plates are alternately laminated, in which the end face of the internal electrode plate is exposed on the side end face of the multilayer ceramic capacitor, and the end face of the internal electrode plate is exposed on the side end face. The general formula (I
) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, X is a phenyl group; a biphenyl group; and at least one of the phenyl group and biphenyl group is O, CO, S,
SO_2, CH_2, C(CH_3)_2 and C(CF
_3) A tetravalent group selected from the group consisting of polyphenyl groups bonded by at least one of _2, Y is a phenyl group; a biphenyl group; at least one of the phenyl group and the biphenyl group is O, CO, S, SO_2, CH_
2, a polyphenyl group bonded by at least one of C(CH_3)_2 and C(CF_3)_2; an alkylene group; and a divalent group selected from the group consisting of a xylylene group). A multilayer ceramic capacitor characterized in that an insulating layer containing a polyimide resin having units is formed. (2) The multilayer ceramic capacitor according to item 1, further comprising an insulating layer made of polyimide resin containing an insulating filler. (3) A ceramic laminate in which ceramic films or thin plates and internal electrode plates are alternately laminated, and the end surfaces of the internal electrode plates are exposed on the side end surfaces of the ceramic laminate,
General formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula,
SO_2, CH_2, C(CH_3)_2 and C(CF
_2) A tetravalent group selected from the group consisting of polyphenyl groups bonded by at least one of _2, Y is a phenyl group; a biphenyl group; at least one of a phenyl group and a biphenyl group, or O, CO, S, SO_2, CH_
2, a polyphenyl group bonded by at least one of C(CH_3)_2 and C(CF_3)_2; an alkylene group; and a divalent group selected from the group consisting of a xylylene group). The carboxyl groups of the polyamic acid resin having the unit are neutralized with a base, and the resulting product is immersed in an electrophoresis bath containing a film-forming agent obtained by diluting with water, and the internal electrode plate of the ceramic laminate is used as an anode for electrophoresis. to precipitate the polyamic acid only on the exposed portions of the internal electrode plates and the vicinity thereof on the side end faces of the ceramic laminate to form a coating layer, and then heat-treat the polyamic acid resin of the coating layer. is imidized to form an insulating layer containing a polyimide resin having a repeating unit represented by the general formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (in the formula, X and Y are as described above) 2. The method of manufacturing a multilayer ceramic capacitor according to claim 1, further comprising: (4) A ceramic laminate in which ceramic films or thin plates and internal electrode plates are alternately laminated, and the end faces of the internal electrode plates are exposed on the side end faces of the ceramic laminate,
General formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula,
SO_2, CH_2, C(CH_3)_2 and C(CF
_3) A tetravalent group selected from the group consisting of polyphenyl groups bonded by at least one of _2, Y is a phenyl group; a biphenyl group; at least one of the phenyl group and the biphenyl group is O, CO, S, SO_2, CH_
2, a polyphenyl group bonded by at least one of C(CH_3)_2 and C(CF_3)_2; an alkylene group; and a divalent group selected from the group consisting of a xylylene group). An electrophoretic bath for forming a film obtained by neutralizing the carboxyl groups of the polyamic acid resin in a composition comprising a polyamic acid resin having the unit and an insulating filler dispersed in the resin and diluting with water. electrophoresis is performed using the internal electrode plate of the ceramic laminate as an anode, and the polyamic acid and the polyamic acid are immersed only in the exposed portion of the internal electrode plate on the side end surface of the ceramic laminate and in the vicinity thereof. The insulating filler coated with is precipitated to form a coating layer, and then heat-treated to imidize the polyamic acid resin of the coating layer to form a general formula (I
) ▲ There are mathematical formulas, chemical formulas, tables, etc. Claim 2
The method for manufacturing the multilayer ceramic capacitor described above.