JPS63170261A - Dielectric green tape - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to dielectric compositions, particularly low firing temperature dielectric compositions.

Due to their high capacitive efficiency and therefore small size, multilayer ceramic capacitors (MLCs) are the most widely used form of ceramic capacitors. These capacitors are fabricated by stacking and co-firing thin sheets of ceramic dielectric material printed with appropriate electrode turns.

At each node the turn-shaped layer is offset from the adjacent layer so that the electrode layer is exposed at each end of the assembly. The exposed edges of the electrode pattern are coated with a conductive material that electrically connects all layers of the structure.
This forms a group of parallel connected capacitors within the stack.

The thin sheets of ceramic dielectric used for processing MLCs, commonly referred to as "green tape" (unfired tape), are thin layers of microscopic dielectric particles held together by organic polymeric materials. Become. The unfired green tape contains polymers, plasticizers, and polypropylene.
By casting a slurry of dielectric particles dispersed on a carrier such as stainless steel and then controlling the thickness of the cast film by passing the cast slurry down through a doctor blade. Manufactured.

Metallization useful in obtaining electrical conductors for multilayer capacitors usually consists of applying such particles to the green tape in the form of a dispersion of fine metal particles in an inert liquid medium. Although the "green tape" method described above is relatively widely used, there are nevertheless other operations in which MLCs can be made using the dielectric compositions of the present invention. One technique is the so-called "wet method." 1
In terms of aspects, this may consist of passing a flat substrate through a falling sheet of dielectric slip one or more times to form a dielectric layer (see )-Leh et al., U.S. Pat. (See 71st No. 487). One other way to implement the "wet method" is to brush a number of thin layers of dielectric slip onto a substrate to assemble a thick dielectric layer (Pern, U.S. Pat. No. 4,283,753). (see issue).

Another method of making MLCs is to form a yeast of dielectric material and then screen print the dielectric and metal layers alternately with drying steps until the designed structure is completed. Yes. A second electrode layer is then printed on top of the dielectric layer and the entire assembly is co-fired.

Monolithic multilayer capacitors are typically manufactured by co-firing barium titanate-based formulations and conductive electrode materials at temperatures of 1200-1400° C. in an oxidizing atmosphere.

This method results in durable, well-sintered capacitors with high dielectric constants (eg, greater than 1000). However, firing under these conditions requires electrode materials with high melting points, good oxidation resistance at elevated temperatures, sinterability at electrode ripening temperatures, and a tendency to interact with dielectrics at sintering temperatures. These requirements are:
The selection of electrode materials is based on the precious metals platinum and noradium.
Or platinum, /! ! Limited to alloys of radium and gold.

This is intended for the production of monolithic multilayer capacitors. T, L.

See also US Pat. No. 3,872,360 to Seaard.

The dielectric material has been modified to (1) have good dielectric properties (high dielectric constant and low dissipation factor) after firing in a reducing atmosphere so that the base metal can be used as an electrode;
and (or) (2) silver (which has a lower melting point (962°C) than other precious metals) at 950°C or higher, so that it can be used in electrode formation. If it is possible to sinter at much lower temperatures, savings in electrode cost can be realized.

Attempts have been made to modify barium titanate ceramics so that they can be fired in reducing (eg hydrogen) or inert (eg argon, nitrogen) atmospheres. Temperature coefficient IH% of electrical properties such as dielectric constant, dissipation factor, and capacitance compared to conventional air-fired compositions.
The use of this approach is somewhat limited in that it is intermediate. Additionally, maintaining an inert or reducing atmosphere adds production costs compared to firing in air. An example of this approach is the (-) metal electrode (e.g., N
i, Co, Fe) and modified barium titanate (MnO
2, Fe 20 B, COO2, CaZrO3), which is fired in an inert atmosphere width of about 1300°C (
No. 3,75 S. 177 to Buehler, which discloses (column 3, lines 33-34).

Some attempts have been made to lower the ripening temperature of dielectrics by mixing high temperature ferroelectric phases (titanic acid, zirconic acid, etc.) with glasses that ripen at relatively low temperatures. An example of this approach is Maher's U.S. Pat.
, 619,220, Pern U.S. Pat. No. 3,638.
No. 084, Maher, US Pat. No. 3,682,766, and Maher, US Pat. No. 3,811.937. A disadvantage of this technique is that the dilution effect of the glass often results in a relatively low dielectric constant of the mixture.

Another method for lowering the sintering temperature of titanate-based dielectrics
The technique relies on the use of "sintering aids".

Addition of bismuth oxide or bentonite to barium titanate reduces the ripening temperature to about 1200° C. (Nelson et al., US Pat. No. 2,908,579). As described in U.S. Pat. No. 2,626,220 to Turnafer et al., the addition of phosphoric acid to titanic acid
A ripening temperature of ~1290°C can be obtained. but,
In each of these cases, the reduction in ripening temperature is not sufficient to allow the use of co-fired silver electrodes, and dielectric properties are often compromised.

Compositions that provide a high dielectric constant (e.g., 1000 or more) and a low dissipation factor (e.g., 5%, preferably less than 2%), and which sinter in air at low temperatures (e.g., below 1000°C). is needed. Due to this,
Co-firing with silver or palladium/silver electrodes is possible, thus greatly reducing the cost of high dielectric constant multilayer capacitors.

N., N., Krejnik et al.
s-3olidState2.63~65.1960)
are, inter alia, pb'rio3 and PbMgO15W
Solid solutions between 0.503 and 0.503 are reported. Obviously, 0
A wide range of compositions with ~80% pb'rio3 were investigated (see Figure 2).

No suggestion is made of the manufacture of multilayer capacitors. In a second paper from the same laboratory, G, A,
Smolensky et al. (Soviet Physics-8
5.714.1961) have reported several solid solution studies, including those of Kleinik et al. Calcination was similarly carried out in PbO vapor. Phase transitions are discussed. What is clearly the third paper in this series, A.1. Zaslavsky et al. (5ov
iet Physics-Crystallograp
X-ray structural studies are reported in hy7.577.1963).

Prixner US Pat. No. 3,472,777 discloses the production of ferroelectric ceramic disks by a two-stage firing process. Each firing process is performed at 800° to 1200°C in air.
It is taught that this occurs within the range of In the only example, calcination was at 1050°C. Prixner discloses various dielectric compositions, such as PbMgV3T1v3W1/3o3 and Y-containing compositions.

More recently, Bouchiard has successfully approached the solution of the problem of obtaining dielectric compositions with low firing temperatures and high dielectric constants such as 6000 for use in ZSU type capacitors. These substituted lead titanate compositions have the following formula: (SrxPb,-,Ti05)&(PbMgOW05)
1. , (wherein, X=0~0.3, r=0.45~
0.55, a=0.35-0.5, s=0.55-0.
45.1) = 0.5-0.65, Σ(r+5) = 1 and Σ(a+b) = 1) Such materials are described in U.S. Pat. No. 4,048,546.4.
063,341 and 4,228,482 (all to Butiard) have been intermediated. More recently, British patent application 2,115.40OA has the formula PbT11-x-yM
A very similar composition is disclosed that has a low sintering temperature corresponding to gxWy○3, where X and y range from 0.25 to 0.35. These materials are made by mixing the corresponding metal oxides and smoldering this mixture at 700-750°C. These materials are
It is sintered at 800-950°C, which is lower than the melting point of silver. Some of the compositions of this British application are identical in composition to those of Bouchiard and are therefore expected to have the same properties.

Despite substantial advances in obtaining high dielectric constants, the electronics industry is still struggling with even higher dielectric constants (K) of the order of 8,000 and even higher than 85/15 and 70/30. It is anticipated that there will be a need for dielectric compositions that can be used with conventional silver-containing electrodes, such as radium/silver electrodes.

In view of the electronic industry's steadily increasing requirements for improved tape dielectrics, the present invention provides a lead titanate based dielectric suitable for ZSU type service with a dielectric constant of 8000 and even higher. Directed to body composition.

More particularly, the present invention, in a first aspect thereof, provides a composition for forming a densified dielectric body at low firing temperatures, consisting of a mixture of fine particles consisting essentially of: directed towards.

(a) Formula: (5rxPb 1 +xTiO3)a
(PbMg rWsO5)b (where x; 0 to 0.3
, r=0.45~0.55, a=0.45'~0.6
, s=0.55 to α45 and b=t55 to 0.4, and the metal oxide, metal oxide precursor or its multi-element oxide in molar ratio to Σ(r+5)=1 and Σ(a+b)==1. 95.5 to 994% by weight of a mixture of reaction products (b) consisting essentially of (1) 2 of a transition metal selected from the group consisting of Co, N1, Cr, Mn and mixtures thereof;
Original oxide 0.1 to 1.0% by weight, (2) Cd titanate,
0.25-1.5% by weight of Zn titanate or mixtures thereof; and (3) a multi-component oxidation selected from the group consisting of Cd zirconate, Zn zirconate, Cd stannate, Zn stannate and mixtures thereof. 0.25-2.0% by weight of a mixture of metal oxides or their precursors 4.5-0
．． 6% by weight (substantially all particles have a largest dimension of 10
(smaller than μm).

In a second aspect, the present invention is directed to a tape casting composition comprising a dielectric composition as described above dispersed in a solution of a binder polymer in a volatile non-aqueous solvent.

In a third aspect, the invention provides for casting the dispersion described above onto a flexible substrate, such as a steel belt or a polymeric film, and heating the cast layer to remove the volatile solvent. Directed to a method of forming green tape by removing.

In a fourth aspect, the invention provides that the edges of the electrodes printed from alternating layers are exposed at opposite ends of the laminated structure, and the exposed ends of the patterned electrodes are each electrically connected by a conductive coating thereon. It is directed to a capacitor made by laminating and co-firing a plurality of the green tape layers described above, which are printed with suitable electrodes, o-turns, in an offset manner so as to be connected.

In a fifth aspect, the invention is directed to screen-printable thick film compositions such as the dielectric compositions described above dispersed in an organic medium.

A. Inorganic Component As suggested by Part 2 above, when the composition of the present invention is fired, component (a) is doped with small amounts of (b) transition metal oxide and zirconic acid and stannic acid. resulting in a substantially solid solution.

However, prior to firing, these compositions may differ from separate oxides, or from solid solutions or compounds of two or more oxides, depending on the degree of smoldering to which the components have been subjected. good.

Although calcination is not absolutely necessary, it is recognized that it is much more preferable to calcinate at least a large portion of the mixture of particles described above in air so that shrinkage during calcination can be minimized. It will be done. However, the extent of smoldering will depend on the particular application and the extent of firing to effect the formation of the sintered dielectric. Obviously, relatively severe calcinations tend to reduce the number of phases present and the composition approaches a single solid solution state. It is preferable to smolder at least component (a) in air. Appropriate smoking conditions are 1000-15
00'F (513-816C) 1% and especially 150
0-1500"F (704-816C). Baking time should be at least 0.5 hour, and preferably at least 1.0 hour. Baking time of 2 hours is suitable. It has been found that it is possible to use it for a long time.

Ingredients include metal oxides, metal oxide precursors and (
or) may be in the form of a reaction product of a metal oxide of the metals indicated above. The term "metal oxide precursor" means a compound that is converted to a metal oxide upon smoldering or calcination.

These include carbonates, hydroxides and nitrates. For example, during smoking MgCO3 is converted to MgO, thus MgCO3 is a precursor of MgO. The term "reaction product" means a compound or solid solution of a metal oxide that can be produced from a metal oxide. for example,
Multi-component oxide R03 is converted into pbo and Ti by calcination.
It can be generated from O2. Thus, the Pb and T1 components can be added to the composition either separately as pbo and TiO2 or as already formed pb'rio3.

Generally, the composition is made by the following steps: (1) Wet milling of the dispersion (mixing) (2) Removal of water (drying) (3) Granulation (4) Baking (5) Granulation (6 ) Wet milling (particle size control) However, these steps are not necessarily in the same order for each component. For example, the transition metal oxide is PbTiO
It may be preferable to premix with 50 single components such as 3 (which undergo steps (1) to 5). This premix is then added to the other ingredients of (a) which undergo step (1) first step 6) plus drying and granulation. To the resulting granulated mixture (b)
Add the remainder of the ingredients and mill, dry and granulate the final mixture. In this operation, which is designed to obtain a more homogeneous mixture of all components, the transition metal components are smoked twice, but the multi-element oxides are not smoked at all. Whichever scheme of mixing is used, a completely uniform distribution of all ingredients is essential, and the degree of smoldering required is determined by the degree of shrinkage allowed when the mixture is fired.

As used above in this invention, the term "granulation" refers to the use of a vibrating screen to disperse agglomerated particles.

In order to obtain even better burnout and sintering properties, it is preferred that the surface area of the dielectric particles is at least 0,5 m2/g and preferably 5 m2/I.

Still higher surface areas, e.g. 1 or IL2/Ii or higher, can be used, but their advantage lies in the fact that they require an organic medium of large surface area particles to obtain a certain dispersion viscosity. must be balanced against. Additionally, substantially all particles should be smaller than 10 μm in their largest dimension.

B. Green Tape Casting Solution As mentioned above, the green tape of the dielectric composition of the present invention is formed by casting a polymeric binder and a volatile organic solvent onto a flexible substrate, such as a steel belt or a polymeric film. It is made by casting a dispersion of dielectric material in solution and then heating the cast layer to remove the volatile solvent therefrom.

The organic medium in which the ceramic solid is dispersed includes a volatile organic solvent and optionally other dissolved materials such as plasticizers, mold release agents, dispersants, stripping agents, antifouling agents and wetting agents. consisting of a polymeric binder dissolved in

In order to obtain better bonding efficiency, it is preferred to use at least 5 volumes of polymeric binder to 90 volumes of ceramic solid.

However, it is more preferred to use less than 20 volumes of polymeric binder in 80 volumes of ceramic solid. Within these limits, it is desirable to use the smallest possible amount of binder to solids in order to reduce the amount of organics that must be removed by pyrolysis.

In the past, various polymeric materials have been used, such as poly(vinyl butyral), poly(vinyl acetate), poly(vinyl alcohol), cellulosic polymers such as methylcellulose, ethylcellulose, hydroxyethylcellulose, methylhydroxyethylcellulose, atactic Silicone polymers such as polypropylene, polyethylene, poly(methylsiloxane), poly(methylphenylsiloxane), polystyrene, butadiene/styrene copolymers, polystyrene, poly(vinylpyrrolidone), polyamides, high molecular weight polyethers, oxidized Copolymers of ethylene and propylene oxide, polyacrylamides, and various copolymers and polymers of sodium polyacrylate, poly(lower alkyl acrylate), poly(lower alkyl methacrylate), and acrylic acid and lower alkyl methacrylate. Various acrylic polymers such as
Used as a binder for green tape.

Copolymers of ethyl methacrylate and methyl acrylate and terpolymers of ethyl acrylate, methyl methacrylate and methacrylic acid have been used previously as binders for pour casting materials.

More recently, U.S. Patent Application 5N filed June 7, 1983
Usura in 501,978 can contain 0-100% by weight of 01-8 alkyl methacrylate, 100-01% by weight of 01-8 alkyl acrylate, and 0-5% by weight of ethylenically unsaturated carboleic acid or amine. discloses an organic binder that is a mixture of polypolymers. Polymers are preferred for use in the dielectric compositions of the invention since they allow the use of a minimum amount of binder and a maximum amount of dielectric solids. For this reason, the Usula patent application cited above is incorporated herein by reference.

The solvent components of the casting solution are selected to obtain complete solution of the polymer and high volatility such that the solvent can be evaporated from the dispersion by application of relatively low levels of heat at atmospheric pressure. In addition, the solvent must have a boiling point sufficiently lower than the boiling point and decomposition point of any other additives present in the organic medium. Thus, solvents with atmospheric pressure boiling points below 150°C are most often used. Such solvents include (benzene, acetone, xylene, methanol, ethanol, methyl ethyl ketone, 1.Ll-
Trichloroethane, tetrachloroethylene, amyl acetate, intanediol-1,3-monoisobutyric acid 2,2.4
-) Includes ethyl, toluene and methylene chloride.

Often, the organic medium is present in a small amount relative to the binder polymer.
It also contains a plasticizer, which helps lower the glass transition temperature (Tg) of the binder polymer. However, the use of such materials should be minimized to reduce the amount of organic material that must be removed when firing films cast from organic materials. Of course, the choice of plasticizer is determined primarily by the polymer that has to be modified. Among the plasticizers used in various binder systems are diethyl phthalate, dibutyl 7thalate, 7
These include octyl tarate, butylbenzyl heptatarate, alkyl phosphates, polyalkylene glycols, glycerol, poly(ethylene oxide)s, hydroxyethylated alkylphenols, dialkyldithiophosphates, and poly(isobutylene). Of course, butyldundyl phthalate is most often used in acrylic polymer systems because it can be used effectively at relatively low concentrations.

C0 Thick Film Casting It may often be desirable to apply the composition of the present invention as a master film yeast by techniques such as screen printing. When the dispersion is to be applied as a thick film yeast, conventional floating film organic media can be used with appropriate rheology adjustment and low volatility solvents. In this case, the composition is
so that they can easily pass through the screen,
It must have a suitable viscosity. Besides, they should be thixotropic in order to cure quickly after they are screened and thereby obtain good resolution. Although rheological properties are of primary importance, the organic medium also provides adequate wetting of solids and solvents, good drying rates, dry film strength to withstand rough handling, and good sinterability. Preferably, it is prescribed.

In view of all these criteria, a wide variety of inert liquids can be used as the organic medium. The organic medium for most thick film compositions is typically a solution of a resin in a solvent, often a solvent solution containing both the resin and a thixotropic agent. The solvent usually has a boiling point within the range of 130-350°C.

Particularly suitable resins for this purpose are polymethacrylates of lower alcohols and mottyl ether of ethylene glycol monoacetate.

The most widely used solvents for applications in floating films are kerosene, diptyl phthalate, butyl carpitol, butyl carpitol acetate, hexylene glycol and other solvents such as high boiling alcohols and alcohol esters. and thiols such as alpha or beta terpineol or mixtures thereof. Various combinations of these and other solvents are formulated to obtain the desired viscosity and volatility requirements for each application.

Among the commonly used thixotropic agents are hydrogenated castor oil and their derivatives.

Of course, no viscosity reduction (5he) is inherent in any suspension.
It is not always necessary to incorporate a thixotropic agent, as the properties of the solvent/resin in combination with art, hinning) may alone be suitable in this regard.

The ratio of organic medium to inorganic solids in the dispersion can vary widely and depends on the manner in which the dispersant is to be applied and the type of organic medium used.

Usually, to achieve good coverage, the dispersion is
Complementarily contains 60-90% solids and 40-10% organic medium by weight. Such dispersions are usually semi-solid in consistency and are commonly referred to as "R-st."

Yeast is conveniently produced in a 30-mill type mill. The viscosity of yeast is typically within the following ranges as measured at room temperature on a Brookfield viscometer at low, medium and high speeds: 0.2 100-5000 - 300-200
0 preferred 600-1500 most preferred 440-400: 100-25゛0 preferred 140-200 most preferred 584 7-40 -10-25
Preferences 12-18 The amount and type of organic medium most preferably utilized depends primarily on the final desired formulation viscosity and print thickness.

D. Capacity Processing As mentioned above, many multilayer capacitors are fabricated by printing a desired pattern of electrode metallization onto a dielectric substrate that is green tape. The printed dielectric substrates are stacked, laminated, and cut to form the i1 capacitor structure. The green dielectric material is then fired to remove the organic medium from the electrode material as well as the organic binder from the dielectric material. Removal of these materials is carried out by evaporation and pyrolysis during the calcination operation.

In some cases it may be desirable to also insert a pre-drying period before firing. The green tape typically has a thickness of about 12 to 3 mils, and when fired has a thickness of about 0.9 to 1.0 mils.

When firing the capacitor assembly described above, the first step is to slowly heat the assembly to 100-550°C (this is
It is preferred to use a method that is effective in removing all of the organic material without damage to the laminate assembly. Typically, this organic burnout period is 18-24 hours to ensure removal of organics. When this is completed, the assembly is then heated relatively quickly to the desired sintering temperature.

The desired sintering temperature is determined by the physical and chemical properties of the dielectric material. Usually the sintering temperature is selected to obtain maximum densification of the dielectric material. In the case of the dielectric composition of the invention, this temperature ranges from 900 to 1050<0>C. However, it is recognized by those skilled in the art of capacitor fabrication that maximum densification is not always necessary.

Accordingly, the term "sintering temperature" refers to the temperature (as well as the amount of time) that achieves the degree of densification of the dielectric material desired for a particular capacitor application. Although the sintering time also varies depending on the dielectric composition, a time of about 2 hours is usually suitable at this sintering temperature.

Once sintering is complete, the rate of cooling to external temperature is carefully controlled depending on the component's resistance to thermal shock.

The following properties that are relevant to the proper functioning of a given capacitor are listed in the examples.

E, capacitance scatter, o capacitance is calculated mathematically as C=KAN divided by t, where K is the dielectric constant, A is the area overlap of the electrodes, N is the number of dielectric layers, and t is the dielectric constant. is a measure of the ability of a material to store charge, expressed as body layer thickness.

The units of capacitance are farads or fractions thereof, such as microfarads (10-' farads), nanofarads (10-' farads), or picrofarads (1-12 farads).

F, dissipation factor Dissipation''* (DF) is a measure of the phase difference between voltage and current. In a perfect capacitor, the phase difference is 90
°. However, in practical dielectric systems, the amount σ is less than 90° due to leakage and decay losses. especially,
DF is the tangent of the angle σ.

G, Insulation Resistance Insulation resistance (IR) is a measure of a charged capacitor's ability to resist leakage during DC current. Insulation resistance is constant for any given dielectric system regardless of capacitance.

The following examples and comparative displays are presented to illustrate the advantages of the present invention. In the examples, the specification, and the claims, all parts, as far as examples are concerned,
Percentages, proportions, etc. are by weight.

Examples 1 to 5 The following processing steps resulted in a ratio of 0 to 4010
．． Two quantities of low firing dielectric compositions were made: 60 and 0.5010.50.

(1) 1 large mill treatment (2) drying (3) granulation (4) roasting (5) granulation (6) resin mill treatment Refers to the milling process carried out using

The organic medium is a solution of binder polymer in an organic solvent.

Three additional quantities of dielectric compositions with intermediate ψ ratios were prepared by blending appropriate proportions of the two above-mentioned materials. The resulting five compositions were then used in the manner described above to form green tapes, which were then used to fabricate multilayer capacitors that differed only in the dielectric material used. The properties of the capacitors formed from them are shown in Table 1 below: Table 1 PbO63,163,463,864,364,7Mg
CO58,17,87,57,26,9'rio2 9
．． 19.810.411.011.6WO319,71
9,018,317,516,8 (mol 1 PbTi05 3B, 6 41.0 43.5
45.9 48.5Pb(MgW)03 57.
7 55.4 55.0 50.7 48.3Mg0
3.7 3.6 5.5 5.4
5.4 Firing temperature ℃ 1038103810381058
1038 Sintered dielectric properties K (25℃ odor) Q5437 6140 7004
7 (5105790TCC', %a0.10℃
+, a, o +2.8 -10.9 -16.4
-25.535℃ -4,6-2,8+2.0
+15.5 +31.950'C-13,0-9,9
-4,1+24.7"+71.385℃ -50,2
−23,7−24,1+12.7 +131.3(υ
%, DF (IVA) 1.07 1.74 5.5
6' 6.91 4.90x -111
11 a O, 400, 4250, 450, 4
750,50b O,600,5750
,550,5250,50(1)5. c and TCC8
Based on 5,:, the potential is 13,000.

The above data show that substantial effects were obtained on all of the properties tested. With increasing ratio, the Curie peak shifts towards higher temperatures, so the values of K and DF at room temperature increase, not surprisingly. These data show that very high latent room temperature values can be obtained with the present invention.

Example 6-B Two amounts of low firing dielectric compositions were prepared in which the amount of ZnTi03 was 0 and 1.0% by weight.

First, a premix of MnO2, Coo, and PbTiO3 was prepared by ball milling a 55% water component. The ball milled mixture was then heated to 450
It was dried for 12 hours at 0.degree. C., granulated through a 40 mesh screen, smoked for 2 hours at 1550.degree. C., and then granulated once again. The remaining ingredients were then prepared by the following order: (1) Wet milling (2) Drying (3) Granulation (4) Smoking (5) Granulation (6) Resin milling with and without ZnTiO3 A mixture was prepared and portions thereof were blended to form a mixture with an intermediate amount of ZnTiO3. .

The milled dispersion of the composition solids in the acrylic polymer solution was then used to mold green tape, from which multilayer capacitors were manufactured in the manner described above. The electrical properties of capacitors formed from these are shown in Table 2 below.

Table 2 Effect of ZnTi03 addition on firing range on side bending
□ □ □ Dielectric composition ・(Weight s> PbO64,3659 63.6 MgCO37,17,07,0 Ti02 11.1 1t1 1tOw
o3 17.2 17.2 17.1C
oO0,20,20,2 Mn0 O,I Q,1 0.1
ZnTi05 - 0.5 1.0 usable sintering at 1038℃ None Yes Yes 10
At 10℃ Without Reeds With 982℃
In No None Yes The data in Table 2 shows that the addition of very small amounts of ZnTiO3
This shows that it was effective because it lowered the sintering temperature of the dielectric composition by 0°C.

Examples 9-16 A series of eight compositions were prepared by adding various amounts and types of doping agents to the compositions of the present invention, and their effects on the properties of the fired dielectrics, particularly the dissipation factor (DF). observed the effect of

In the case of Examples 9 to 11 and 16, the baking operation was followed by 5 r.
The compositions were prepared in one step in the following sequence, except that TiO3 and/or ZnTiO3 were added to the mixture.

(1) Wet milling (2) Drying (3) Granulation (4) Smoking (5) Granulation (6) Resin milling Then 1 Resin milling dispersion of composition solids in solution of acrylic polymer A green tape was cast using a green tape, and a multilayer capacitor was manufactured from it using the method described above. The electrical properties of capacitors formed from these are shown in Table 3 below.

A comparison of Examples 9 and 10 shows that Coo and MnO2 are jointly effective in lowering DF. Similarly, addition of COo alone (Example 14) resulted in quite low DF values. Examples 11 to 13 are MnO2, CeO
2 and NiO are each shown to be effective in lowering DF. However, comparing Example 15 to Control Example 16 shows that Fer205 did not reduce DF', but increased it.

Examples 17-20 Two paired compositions were prepared to provide Cd for lifetime performance.
The effect of adding SnO3 was observed. Starting with 5rT103, ZnTiO3 and Cd5f103 were added in step (4).
) was added to the smoldering product, the composition was prepared by the following sequence of steps: (1) wet milling (2) drying (3) granulation (4) smoldering (5) Granulation (6) Wet milling (force drying/8) Granulation (9) Resin milling Next, resin milling dispersion of the composition solid in solution of the acrylic polymer is used to cast green tape. From this, a multilayer capacitor was manufactured using the method described above. The electrical properties of capacitors formed from these are shown in Table 4 below: Table 4 Dielectric composition (wt%) PbO62,
061,462,061,4MgCO36,56,46
,56,4 Ti02 11.4 11.3 11.4
11. ! 1wo3 15.8 15.6
15.8 15.6Coo O,2
0,20,20,2Mn02 0.1
0.1 0.1 0. l5rTi03
3.5 3.5 3.5 5.5ZnTi03
0.5 0.5 0.5 0.5C
dSn05-1.0-1
．． 0 Powder properties Particle diameter μm 10 inches <0.95 <0.92 <
0.95 <0.9250% <1.80
<1.60 <1.80 <1.6090%
<5.45 <2.70 <3.45
<2.70 Surface area m2g 50.7 (Li 6.7(2) -5,76,7(2) Firing temperature C
968968968968 (1) 16 hours of milling (2) 32 hours of milling (3) 48 hours, 100V, 125°C This shows that it was effective in improving the results.

Examples 21-30 Two further series of compositions were prepared in which the effect of various dopant concentrations on fired dielectric properties was observed. In the first series (Examples 21-25), Mn0
2 from 0.1 to 0.5 and the second series (Example 2
6 to 30), the amount of C00 is 0.1 to 0.5
I raised it to Both series of compositions were produced and evaluated in the same manner as in Examples 9-16. The properties of ■, C made from these are shown in Table 5 below: Examples 31-39 A series of nine compositions were prepared in early summer, in which the amounts of WO2, MgCO3, pbo and 'rio2 were prepared. Made some changes. In particular, two compositions were prepared in which each of the four components listed above was present in excess or deficiency. MLCs were prepared in the manner described above using each of the compositions and a control using calcination temperatures of 996°C and 1024°C. The dielectric compositions and properties of MLCs made from them are shown in Table 6 below.

Table 6 Example A 37 Dielectric composition PbO62,1 Mgcog 44 'r1o2 10.9 WOs 15.6 TMO" 1,5 ZnTi05 0.5 SrTi05 5.0 Conditions pbo Excess firing temperature t: 9961024K (at 25°C) 7465 8078 % DF (IV/mil) α74 2.0035℃ −
4,4+6.3 50°C -12,8-t5 25°C eD3.3 to 85°C &4K &4 to -X-TMO-Transition metal oxide containing 5 tons of MnO2, 15% of 1 by weight.

(Continued) (Weight%) 62.0 6α7 6.66.5 I Q, 3 12.0 16.3 15.8 1.5 t5 0.5 Q, 5 3.0 5.0 'rtoz deficiency 'rio2 Excess 5699 6B50 951 10240.26 t
oo 122 4.52+6.6 -α4 -7.4
-5.2-7.6 -5.2 Now 5.9 +s,
.

-169-16,4+15.9 +12.7-37.1
-39.1 +52.0 +55.1g1″10.
9 K a.

” 2.8K 2.9K 0.6 FoO and 80% PbTi05 The above data indicate that small amounts of metal oxides are
It shows that it can have a very beneficial effect in reducing the F characteristics.

Patent applicant: 2 people other than E.I. du Pont de Nemoers & Compagnie

Claims (1)

[Claims] 1) Essentially formula (a): (Sr_xPb_1_-_xTiO_3)_
a(PbMg_rW_sO_3)_b (in the formula x=0 to 0
．． 3, r=0.45-0.55, a=0.45-0.6
, s=0.55-0.45, b=1.55-0.4 and Σ(r+s)=1 or Σ(a+b)=1). 95.5-9
9.4% by weight, and (b) essentially (1) Co, Ni,
0.1-1.0% by weight of a binary oxide of a transition metal selected from the group consisting of Cr, Mn and mixtures thereof, (2)
Cd titanate, Zn titanate or mixture thereof 0.2
and (3) 0.25 to 2.5% by weight of a multi-element oxide selected from the group consisting of Cd zirconate, Zn zirconate, Cd stannate, Zn stannate and mixtures thereof.
0% by weight of a mixture of metal oxides or their precursors (substantially all particles are
Maximum dimension is less than 10 μm and at least 0.5 m^
2/g) is dispersed in an organic medium consisting of a polymeric binder dissolved in an organic solvent. A dielectric green tape consisting of a layer of a composition obtained by removing an organic solvent from a composition for forming an object. 2) The green tape according to claim 1, wherein the organic solvent is a volatile non-aqueous solvent and the dispersion has a viscosity that allows molding. 3) (1) Essentially formula (a): (Sr_xPb_1_-_xTiO_3)_
a(PbMg_rW_sO_3)_b (in the formula x=0 to 0
．． 3, r=0.45-0.55, a=0.45-0.6
, s=0.55-0.45, b=1.55-0.4 and Σ(r+s)=1 or Σ(a+b)=1). 95.5-9
9.4% by weight, and (b) 0.1 to 1 binary oxide of a transition metal selected from the group consisting essentially of (1) Co, Ni, Cr, Mn and mixtures thereof;
．． 0% by weight, (2) 0.25-1.5% by weight of Cd titanate, Zn titanate or a mixture thereof, and (3) Cd zirconate.
, Zn zirconate, Cd stannate, Zn stannate and mixtures thereof 0.25
-2.0% by weight of a mixture of metal oxides or their precursors (substantially all particles have a largest dimension of less than 10 μm and at least 0.6% by weight)
A mixture of fine particles consisting of components (having a surface area of 5 m^2/g) is densified at a low calcination temperature, where the mixture is dispersed in an organic medium consisting of a polymeric binder dissolved in an organic solvent. Each of the plurality of layers of the dielectric green tape comprises a layer of a composition obtained by removing the organic solvent from the composition for forming a dielectric object.
applying a layer of conductive electrode material dispersed in an organic medium; (2) stacking a plurality of green tapes bearing the electrode layer to form an assembly of alternating layers of green tape and electrode material; and (3) firing the assembly of step (2) at 900-1050°C to remove the organic medium and organic binder and sinter the conductive electrode material and dielectric material. How to form integrated capacitors.