JP2005063707A - Electrode paste, and manufacturing method of ceramic electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode paste capable of improving characteristics of an electrode film by expressing a high temperature sintering restraining action and a low temperature sintering restraining action in a baking process. <P>SOLUTION: The electrode paste 1 contains at least metal powder, more than one kind of dielectric precursor material 8 forming a dielectric by baking, and dielectric powder. Sintering among metal fine particles 2 at low temperature is restrained by the dielectric precursor material 8 in a molecular state, and sintering among metal fine particles 2 at high temperature is restrained by the fine particles of the dielectric precursor material 8. The sintering can be restrained over a whole range of temperature ranging from low temperature to high temperature in the baking process. The paste is a kind of all-round electrode paste which can be utilized for high temperature sintering and low temperature sintering. The electrode paste for a thick film or a thin film can be provided by adjusting the viscosity by adding suitable quantity of organic solvent 10 and resin 12. It is suitable for the dielectric precursor material 8 to contain 0.1 to 10 mass% of metal against the total mass of the metal powder, and a suitable content of the dielectric powder is 0.1 to 30 mass%. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrode paste for forming an electrode in a ceramic electronic component. More specifically, the present invention relates to an electrode paste using a dielectric precursor and dielectric fine particles as a sintering inhibitor for metal fine particles forming an electrode, and a ceramic electronic component. It relates to a manufacturing method.
[0002]
[Prior art]
Usually, the electrode paste is composed of noble metal or base metal fine metal particles, an organic solvent in which the fine metal particles are dispersed, and a viscosity adjusting resin. The electrode paste is applied to the surface of the green sheet in a predetermined pattern to form an electrode paste film, and the green sheet and the electrode paste film are integrally fired to simultaneously form electrodes on the ceramic substrate.
[0003]
Ceramic powder is kneaded with an organic binder and a solvent to form a slurry, and the slurry is formed into a sheet to form a green sheet. Therefore, when the green sheet is fired, the organic component is removed, and the green sheet is changed into a ceramic substrate while contracting. At the same time, the electrode paste film also changes into an electrode film while shrinking due to removal of organic components. When there is a large difference in the firing shrinkage rate between the green sheet and the electrode paste film, there is a risk that the electrode film is peeled off from the ceramic substrate, or the electrode film is locally spheroidized by firing and the electrode film is interrupted.
[0004]
In general, since the metal fine particles have a relatively low melting point, they are melt-bonded to each other by firing, and the film made of the metal fine particles changes into a dense metal film while contracting greatly. On the other hand, since ceramic particles have a higher melting point than metal particles, they only cause surface melting even when fired, and their shrinkage rate is smaller than that of metal particles even when sintered together. For this reason, the firing shrinkage rate of the electrode paste film is generally larger than the firing shrinkage rate of the green sheet, the electrode film is easily peeled off from the ceramic substrate, and the electrode film is likely to be discontinuous.
[0005]
Therefore, it is necessary to make the firing shrinkage rates of the green sheet and the electrode paste film as close as possible. As one of the methods, a technique of mixing dielectric powder with electrode paste has been developed. This technique is disclosed in Japanese Patent Laid-Open No. 2001-291634 as an example of the prior art. The composition of the dielectric powder is substantially the same as that of the main component of the ceramic constituting the green sheet, and this added dielectric powder is called a co-material.
[0006]
When the dielectric powder is mixed in the electrode paste, the dielectric fine particles are interposed between the metal fine particles in the electrode paste film. When this electrode paste film is baked, the dielectric fine particles inhibit the fusion bond between the metal fine particles, so that the effect of suppressing the sintering of the metal fine particles appears. The action of suppressing the sintering of the metal fine particles immediately produces an effect of reducing the contraction rate of the electrode film. As described above, when the dielectric powder is added to the electrode paste, the effect of suppressing the sintering of the electrode paste film, that is, the effect of suppressing the shrinkage is exhibited.
[0007]
The dielectric powder is set to the same composition as the ceramic main component of the green sheet. This is because the firing shrinkage rate of the electrode paste film is as close as possible to the firing shrinkage rate of the green sheet. For example, the ceramic main component of the green sheet is BaTiO ₃ Then, as the dielectric powder of the electrode paste, similarly BaTiO ₃ A powder is selected. By adding such a dielectric powder, the electrode paste film approximates the composition of the green sheet, and the firing shrinkage characteristics of the electrode paste film and the green sheet approximate to prevent peeling of the electrode film.
[0008]
[Problems to be solved by the invention]
As described above, when dielectric powder is added to the electrode paste, the firing shrinkage rate of the electrode paste film is surely lowered. According to recent research, the reduction in firing shrinkage due to the forced addition of dielectric powder is effectively manifested at higher firing temperatures. However, even if the dielectric powder is added, a certain degree of firing shrinkage always occurs, and it is impossible to completely prevent the firing shrinkage only by adding the dielectric powder. In particular, it has been understood that when the firing temperature is low, the firing shrinkage rate is not sufficiently reduced only by the addition of dielectric powder. This means that even if dielectric powder is added, it is not a countermeasure for suppressing shrinkage in low-temperature firing even if it is a countermeasure for high-temperature firing.
[0009]
Moreover, even if it says high temperature baking, it is actually baked by passing through various temperature processes until reaching a high temperature. For example, even when firing at 1300 ° C., the temperature rises from room temperature to reach 1300 ° C., so that it is already fired even at an intermediate temperature between room temperature and 1300 ° C. before being fired for a long time at 1300 ° C. . Even if there is a shrinkage suppressing effect at 1300 ° C., if there is no shrinkage suppressing effect even when firing at an intermediate temperature of 500 ° C. or 1000 ° C. (low temperature firing), when subjected to high shrinkage at the low temperature firing stage, Inhibition of shrinkage is considered to be half the effect.
[0010]
The shrinkage phenomenon due to the low firing temperature must be determined for another reason. When the firing temperature is low, melting of the metal fine particles is suppressed, and it is considered that the surface of the metal fine particles is melted in the same manner as the ceramic particles, and the metal fine particles are partially melt-bonded between the surfaces. In the low-temperature firing, in the electrode paste film, the metal fine particles that have been separated through a small gap approach each other by firing and are bonded to each other, and shrinkage occurs due to the absence of the gap. Preventing shrinkage due to the disappearance of minute gaps results in suppression of shrinkage due to low-temperature firing.
[0011]
It is clear that shrinkage due to the disappearance of such a minute gap cannot be prevented by the presence of dielectric fine particles. In other words, if the size of the gap is equal to or larger than the particle size of the dielectric fine particles, it is possible to prevent the metal fine particles from being sintered by interposing the dielectric fine particles. However, when the size of the gap is smaller than the particle size of the dielectric fine particles, it becomes impossible to interpose the dielectric fine particles in the gap itself, and other means must be taken to prevent shrinkage.
[0012]
In addition, research is being conducted to reduce the particle size of the dielectric fine particles. In this method, the particle size of the dielectric fine particles is reduced to fill the gaps between the metal fine particles with the dielectric fine particles. However, when the particle size of the metal fine particles becomes small, the particle size of the dielectric fine particles for preventing sintering tends to be inevitably small. At present, nanosize is required as the particle size, and for example, development of dielectric ultrafine particles is required for ultrafine metal particles.
[0013]
FIG. 15 is a schematic diagram for explaining the relationship between the metal fine particle diameter D and the three pocket diameter d. In order to ensure the conductivity of the electrode film, it is required to set the density of the electrode film large. The electrode film density is maximized when the metal fine particles 2 are closely packed, and in this close-packed structure, the three pockets 4 are formed by the three metal fine particles 2 that are in contact with each other.
[0014]
The three pocket diameter d is defined by the maximum diameter of the particles that can enter the three pocket 4. If the dielectric fine particles 6 can be filled in the three pockets 4, it should be possible to maximize the electrode film density and suppress the sintering. In other words, it is necessary to design the diameter of the dielectric fine particles 6 to be not more than the three pocket diameter d. The relationship between the metal fine particle diameter D and the three pocket diameter d is shown in Table 1.
[0015]
<Table 1> Relationship between metal fine particle diameter D and three pocket diameter d
<Number><Metal fine particle diameter D><Three pocket diameter d>
No. 1 0.6μm 0.0929μm
No. 2 0.4μm 0.0618μm
No. 3 0.2μm 0.0309μm
No. 4 0.1μm 0.0154μm
[0016]
Ni fine particles as metal fine particles 2 and BaTiO as dielectric fine particles ₃ Let's take an example using fine particles. In the electrode paste conventionally used, 0.6 μm Ni fine particles are added to 0.1 μm BaTiO. ₃ Fine particles are mixed. In this case, since the three pocket diameter d is 0.0929 μm, 0.1 μm BaTiO is used. ₃ The fine particles are almost well filled into the three pockets.
[0017]
However, in order to increase the density of the multilayer ceramic electronic component, it is required to further reduce the thickness of the electrode film. For example, it has been studied to use Ni fine particles having a diameter D of 0.4 μm or 0.2 μm. At this time, the three pocket diameter d is as extremely small as 0.0618 μm or 0.0309 μm. In order to fill the three pockets 4 with dielectric fine particles, BaTiO having a diameter of 0.06 μm or 0.03 μm is used. ₃ Fine particles are required. Such dielectric fine particles are nanometer-sized BaTiO. ₃ Although called ultrafine particles, it is still in the process of research, but it is still difficult to put into practical use.
[0018]
As described above, in the prior art using an electrode paste in which metal fine particles and dielectric fine particles are mixed, when the diameter of the metal fine particles is reduced, the three pocket diameter is drastically reduced, and there is a limit to the diameter of the usable dielectric fine particles. There was a weak point to do. Thus, when the metal fine particles are close to each other, dielectric fine particles that fill the small gap cannot be expected at present.
[0019]
The firing temperature varies depending on the type of ceramic electronic component, and it is necessary to suppress shrinkage in both high-temperature firing and low-temperature firing. Further, as described above, even if high-temperature firing is performed, a temperature history from low temperature to high temperature is passed, so that not only high-temperature shrinkage countermeasures but also low-temperature shrinkage countermeasures must be taken at the same time. Furthermore, at the manufacturing site, in order to save energy and extend the life of the firing furnace, the temperature for firing ceramics tends to gradually decrease. Therefore, it is extremely important to solve the prevention of shrinkage of minute gaps that cannot be filled with current dielectric fine particles.
[0020]
Therefore, the present invention provides an electrode paste that can realize shrinkage suppression in high-temperature firing by adding dielectric fine particles, and can provide shrinkage suppression in low-temperature firing by supplementing and adding a novel substance. An object of the present invention is to provide an electrode paste corresponding to both high-temperature firing and low-temperature firing, and giving an optimum sintering suppression curve even for firing through an arbitrary temperature history. It is another object of the present invention to provide a novel method for manufacturing a ceramic electronic component in which an electrode paste film is formed on a green sheet using such an electrode paste and the electrode film is formed on a ceramic substrate by firing.
[0021]
[Means for Solving the Problems]
The present invention has been made to solve the above-mentioned problems, and a first embodiment of the present invention includes a metal powder, one or more dielectric precursors that form a dielectric by firing, and a dielectric powder. It is an electrode paste containing at least.
To achieve sintering suppression in the entire temperature range by using dielectric fine particles for high temperature sintering suppression and using one or more dielectric precursors that form a dielectric by firing for low temperature sintering suppression Successful. Large gaps between the metal fine particles are filled with dielectric fine particles to prevent firing shrinkage between the metal fine particles. Further, a small gap between the metal fine particles (not filled with dielectric fine particles) is filled with a molecular dielectric precursor to prevent firing shrinkage between the metal fine particles. The dielectric precursor is a compound that forms a dielectric (ceramics) when fired, and is selected from various metal compounds such as organometallic compounds, organometallic complexes, and organometallic resinates. The metal of these substances means a metal element constituting a dielectric. For example, BaTiO as a dielectric ₃ Ba and Ti are the metals when BaTiO is selected. ₃ The precursor compound of BaTiO3 is obtained by firing. ₃ Means a compound that forms For example, when titanium octylate and barium octylate are baked in an oxidizing atmosphere, organic substances are removed by combustion, and finally BaTiO 3 is removed. ₃ A dielectric is formed. In the electrode paste state, since the dielectric precursor is molecular, any small gaps between the metal fine particles are densely filled with the dielectric precursor. A minute nano-sized three pocket formed by nano-sized metal ultrafine particles can be filled with a dielectric precursor. When the electrode paste film is baked, the dielectric precursor becomes a dielectric in a filled state, and a dielectric can be formed in a gap of any shape. Therefore, this electrode paste can give an optimum sintering suppression curve for a wide range of temperature history from low temperature to high temperature received during firing, and the electrode paste film is prevented from shrinking as much as possible during the firing temperature history process. There is. In addition, even when the firing temperature varies depending on the type of electronic component, it is a universal electrode paste that can be used for a wide range of firing temperatures from high temperature firing to low temperature firing. Use of a dielectric powder having a small particle size can cope with ultrafine metal fine particles, and the multilayer ceramic electronic component can be miniaturized, densified and multi-layered through thinning of the electrode film.
[0022]
The second aspect of the present invention is an electrode containing at least a metal powder, one or more dielectric precursors that form a dielectric by firing, a dielectric powder, and an organic solvent that uniformly disperses these substances. It is a paste.
Since the metal powder, the dielectric powder, and the dielectric precursor are uniformly dispersed in the organic solvent to prepare the electrode paste, the metal powder, the dielectric powder, and the dielectric precursor are uniformly dispersed in the electrode paste. When an electrode paste film is formed using this electrode paste, a solution-like thin film paste can be formed, and the film thickness can be made uniform and the metal film density can be made uniform simultaneously with the thinning of the electrode film.
[0023]
According to a third aspect of the present invention, there is provided a metal powder, one or more dielectric precursors that form a dielectric by firing, a dielectric powder, an organic solvent that uniformly disperses these substances, and a viscosity adjusting agent. It is an electrode paste containing the resin.
Since an appropriate amount of resin for adjusting the viscosity is added, the viscosity of the electrode paste can be freely adjusted, and it is possible to freely meet market demands from high viscosity pastes to low pastes.
[0024]
A fourth aspect of the present invention is an electrode paste in which the dielectric precursor is an organometallic resinate.
An electrode paste in which the dielectric precursor is composed of an organometallic resinate. Organometallic resinates are optimal as the dielectric precursor. The organometallic resinate is an organometallic resinate, and a higher fatty acid metal salt is a representative substance. Examples of organometallic resinates include naphthenate, octylate, stearate, oleate, palmitate, laurate, myristate, benzoate, paratoylate, n-decanoate, metal Alkoxides, metal acetylacetonates and the like are used. By firing these organometallic resinates, BaTiO ₃ , Ba (Ti / Zr) O ₃ , (Ba / Ca) (Ti / Zr) O ₃ , SrTiO ₃ , Pb (Ti / Zr) O ₃ It is possible to easily form a dielectric having an arbitrary shape such as.
[0025]
The fifth embodiment of the present invention is an electrode paste in which the metal content of the dielectric precursor is 0.1 to 10% by mass with respect to the total amount of the metal powder.
If the metal content of the dielectric precursor is added by 0.1 to 10% by mass with respect to the total amount of the metal powder, an electrode film having good conductivity can be formed by reducing the firing shrinkage rate even in low-temperature firing. . The dielectric precursor is usually a metal oxide, and when it is adjusted to a range of 0.1 to 10% by mass of the metal powder, a high-level electrode film required for a ceramic electronic component can be formed. If it is less than 0.1% by mass, the low-temperature sintering is not sufficiently suppressed, and if it exceeds 10% by mass, the conductive performance of the electrode film is affected. Thus, by adding a small amount of a dielectric precursor to the metal component for electrode formation, it is possible to form a dense electrode film with a low firing shrinkage rate even in low-temperature firing.
[0026]
The sixth aspect of the present invention is an electrode paste in which the content of the dielectric powder is 0.1 to 30% by mass with respect to the total amount of the metal powder.
If the content of the dielectric powder is added in an amount of 0.1 to 30% by mass with respect to the total amount of the metal powder, the firing shrinkage rate can be reduced even in high-temperature firing, and an electrode film having good conductivity can be formed. If it is less than 0.1% by mass, the high-temperature sintering is not sufficiently suppressed, and if it exceeds 30% by mass, the conductive properties of the electrode film are affected. By adjusting the range of 0.1 to 30% by mass of the metal powder, an electrode film having advanced characteristics required for ceramic electronic components can be formed. In this way, by adding an appropriate amount of dielectric powder to the metal component for electrode formation, an electrode film having a small firing shrinkage ratio and high density and high surface smoothness can be formed even at high temperature firing.
[0027]
In the seventh aspect of the present invention, the average particle size of the metal fine particles constituting the metal powder is 0.1 to 0.5 μm, and the average particle size of the dielectric fine particles constituting the dielectric powder is 0.05 to The electrode paste is 0.3 μm.
Since fine metal fine particles with an average particle size of 0.1 to 0.5 μm are used, and fine dielectric fine particles with an average particle size of 0.05 to 0.3 μm are used at the same time, the electrode film is further thinned. It becomes possible to do. The reduction in the thickness of the electrode film can realize super-multilayering and ultra-high density of ceramic electronic components, and can contribute to further miniaturization of electronic devices and personal computers, particularly mobile phones.
[0028]
The eighth embodiment of the present invention is an electrode paste configured such that the composition of the dielectric precursor and the dielectric powder coincide with the main component of the dielectric forming the green sheet.
Since the composition of the dielectric powder and the dielectric precursor is configured to correspond to the main component of the dielectric forming the green sheet, the firing shrinkage rate of the electrode paste film is matched to the firing shrinkage rate of the green sheet as much as possible. It becomes possible. The green sheet is a material formed into a sheet shape by kneading dielectric powder, resin, and other components, and changes to a ceramic substrate made of a dielectric material by firing. The dielectric precursor becomes a dielectric upon firing, and the dielectric powder does not change even when fired, and remains a dielectric.
Since these dielectric compositions are composed of the same composition as the main component of the dielectric forming the green sheet, the firing shrinkage rate of the electrode film can be approximated to the firing shrinkage rate of the green sheet. Therefore, even if baked, the electrode film does not peel from the green sheet (ceramic substrate), and a stable electrode film can be excellently formed. Moreover, since the molecular dielectric precursor does not disturb the behavior of the metal fine particles during firing, the metal fine particles can be reliably sintered with each other, and there is an advantage that a stable and uniform electrode film can be formed even at low temperature firing.
[0029]
According to a ninth aspect of the present invention, an electrode paste film is formed on a green sheet using the electrode paste, and the green sheet and the electrode paste film are integrally fired to remove organic components. This is a method for manufacturing a ceramic electronic component in which an electrode film having a desired pattern is formed on a substrate.
If an electrode paste film is formed on the green sheet using the electrode paste, a good quality electrode film can be formed on the ceramic substrate by either high-temperature baking or low-temperature baking. This firing temperature is determined by the temperature at which the green sheet can be sintered, and can provide a revolutionary ceramic electronic component manufacturing method that can cope with the selection of the sintering temperature with a single electrode paste. Even if the electrode film formed by firing is an ultra-thin film, the conductivity is extremely high, and the firing shrinkage rate of the electrode film and the green sheet is almost the same, so an excessive stress acts between the electrode film and the ceramic substrate. Therefore, a long-life ceramic electronic component having high density and high conductivity can be provided. Examples of the ceramic electronic component include a ceramic circuit board, a ceramic capacitor, a ceramic inductor, a ceramic piezoelectric element, and a ceramic actuator. The present invention provides a method for manufacturing ceramic electronic parts that can cope with the conversion of many electronic parts into ceramics.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of an electrode paste and a method for producing a ceramic electronic component according to the present invention will be described in detail with reference to the accompanying drawings.
[0031]
FIG. 1 is a schematic explanatory view of an electrode paste 1 according to the present invention. An electrode paste 1 is prepared in the container 3. Metal powder made of metal fine particles 2, dielectric powder made of dielectric fine particles 6, dielectric precursor 8 having the same composition as the dielectric powder, and organic solvent for uniformly dispersing these materials 2, 6 and 8 10 and resin 12 for adjusting the viscosity are kneaded to form electrode paste 6. The electrode paste 1 is configured so as to have an appropriate viscosity by uniformly mixing and stirring the above-described five kinds of substances.
[0032]
The metal fine particles 2 may be at least one kind or two kinds of single noble metal fine particles made of Ir, Os, Rh, Pd, Ru, Au, Pt, Ag, alloy noble metal fine particles, or base metal fine particles made of other transition metals. . In recent years, from the viewpoint of cost reduction of semiconductors and electronic materials and cost stabilization, conversion from noble metal materials to base metal materials has been attempted, and Ni, Cu, and the like are being used as electrode metal materials instead of noble metals. Therefore, the cost of the electrode paste 1 can be significantly reduced by using base metal fine particles such as Cu fine particles and Ni fine particles in the present invention. In addition, the market price of Cu and Ni is more stable than that of noble metals, which can contribute to price stabilization of the electrode paste 1.
[0033]
The cross-sectional diameter (particle diameter) D of the metal fine particle 2 used in the present invention may be a metal fine particle on the order of μm or a metal ultrafine particle on the order of nm. More specifically, the present invention is not limited to 1 to 10 μm micron-sized metal fine particles and 0.1 to 1 μm submicron-sized metal fine particles, and 1 to 100 nm nano-sized metal ultrafine particles can also be used in the present invention. In particular, in the case of 0.1 to 0.5 μm metal fine particles, the material can be easily obtained, and the production of the electrode paste of the present invention is easy.
[0034]
In particular, since the molecular dielectric precursor 8 is used in the present invention, the molecular dielectric precursor can be filled even in a three pocket formed by nano-sized ultrafine metal particles. When ultrafine metal particles are used in the electrode paste 1, a nano-sized electrode film can be formed, and the three pockets of ultrafine metal particles are filled with a dielectric, so that an ultrathin electrode film can be realized. Contributes to high density and miniaturization of ceramic electronic components.
[0035]
In the present invention, a dielectric powder composed of dielectric fine particles 6 is added to the electrode paste 1. The dielectric fine particles 6 are fine ceramic fine particles and are made of the same material as a ceramic substrate formed by firing a green sheet described later. For example, the main component of the ceramic substrate is BaTiO ₃ If so, BaTiO as the dielectric fine particles 6 ₃ Ceramic fine particles are selected. From this point of view, the dielectric fine particles 6 are BaTiO. ₃ , Ba (Ti / Zr) O ₃ , (Ba / Ca) (Ti / Zr) O ₃ , SrTiO ₃ , (Ba / Sr) TiO ₃ , Pb (Ti / Zr) O ₃ And other dielectrics.
[0036]
When the dielectric fine particles 6 are added to the electrode paste 1, the dielectric fine particles 6 are interposed between the metal fine particles 2 and 2 by kneading the paste. Even when the electrode paste film is fired, the dielectric fine particles 6 have the effect of suppressing the sintering of the metal fine particles 2 and 2 and reducing the shrinkage rate due to the firing. Further, when the dielectric fine particles 6 are made of the same material as the main component of the green sheet, the shrinkage rate due to the firing of the electrode paste film approaches the shrinkage rate of the green sheet, and peeling of the electrode film can be prevented.
[0037]
The cross-sectional diameter (particle size) of the dielectric fine particles 6 used in the present invention may be a dielectric fine particle on the order of μm or a dielectric ultrafine particle on the order of nm. More specifically, the present invention is not limited to 1 to 10 μm micron-sized dielectric fine particles and 0.1 to 1 μm submicron-sized dielectric fine particles, and 1 to 100 nm nano-sized dielectric ultrafine particles can also be used in the present invention. . In particular, in the case of dielectric fine particles of 0.05 to 0.3 μm, the material acquisition is relatively easy, and the production of the electrode paste of the present invention is easy.
[0038]
In the present invention, the dielectric precursor 8 is added to the electrode paste 1. The dielectric precursor 8 means a molecular raw material compound that generates a dielectric by firing. Since the dielectric precursor 8 is a molecule, its particle size is extremely small and can enter any local region. Moreover, the material of the dielectric precursor 8 is set to the same composition as the main component of the dielectric constituting the green sheet, as with the dielectric fine particles 6.
[0039]
The ceramic fine particles constituting the green sheet are dielectric fine particles. This dielectric is, for example, barium titanate (BaTiO ₃ , Abbreviation BT), barium zirconate titanate, strontium titanate (SrTiO) ₃ , Abbreviated ST), barium strontium titanate ((Ba / Sr) TiO) ₃ ), Lead zirconate titanate (Pb (Ti / Zr) O) ₃ ), Calcium titanate, barium zirconate, lithium niobate, lithium tantalate, zinc oxide, alumina, zirconia, aluminum nitride, silicon nitride and the like. Among these, the main component of the ceramic capacitor green sheet is often barium titanate (BT).
[0040]
The dielectric precursor 8 is a molecular compound, and its size is extremely small as described above. That is, the dielectric precursor 8 easily enters the three pockets 4 formed by the metal fine particles 2 and functions to fill such fine regions. Further, it is considered that a thin coating film of the dielectric precursor 8 is formed on the surface of the metal fine particle 2. Therefore, when fired, the dielectric precursor 8 acts to suppress sintering of the metal fine particles 2 while being transformed into a dielectric. Moreover, since the composition of the dielectric precursor 8 is set to the same composition as the main component of the green sheet, it has the effect of bringing the firing shrinkage rate of the electrode paste film close to the firing shrinkage rate of the green sheet. Therefore, the dielectric precursor 8 together with the dielectric fine particles 6 prevents the electrode film from peeling off from the ceramic substrate.
[0041]
The sintering suppressing action of the dielectric fine particles 6 and the dielectric precursor 8 on the metal fine particles 2 will be described. The present inventors consider that the dielectric fine particles 6 are responsible for sintering suppression at high temperatures, and the dielectric precursor 8 is responsible for sintering inhibition at low temperatures. When the electrode paste 1 contains both the dielectric fine particles 6 and the dielectric precursor 8, it is considered that the electrode paste has a sintering suppressing action against a wide range of firing temperatures such as high temperature and low temperature. Since the firing temperature or firing profile is variously changed according to the material of the ceramic material or ceramic electronic component, the electrode paste of the present invention is effective. In addition, since the electrode paste is subjected to a wide range of temperature changes from a low temperature to a high temperature in one firing process, the electrode paste has an effect of suppressing sintering in the entire process of the temperature change.
[0042]
The micro mechanism of sintering suppression is considered as follows. The dielectric fine particles 6 are interposed between the metal fine particles 2 and 2, and the dielectric precursor 8 fills the three pockets 4 or covers the surface of the metal fine particles 2 thinly. At high temperatures, there is a possibility that the metal fine particles 2 are completely melted, and the bonding of the metal fine particles in which the dielectric fine particles 6 are melted is inhibited to suppress sintering. Further, since the metal fine particles 2 melt at a low temperature, the peritoneum due to the dielectric precursor 8 inhibits the bonding between the metal fine particles and suppresses the sintering. Due to such a double sintering inhibiting action, the electrode paste of the present invention exhibits sintering inhibition against both high temperature firing and low temperature firing. Therefore, the present invention can provide an epoch-making electrode paste that smoothly sinters the electrode paste in the temperature range from the low temperature firing region to the high temperature firing region and realizes the sintering suppression control.
[0043]
The dielectric precursor 8 is a raw material compound that generates the above-described dielectric by firing, and any compound that can form a dielectric by firing can be used. As this dielectric precursor, metal compounds such as organometallic compounds, organometallic complexes, organometallic resinates, metal oxides, and metal carbonates can be used. Here, the metal means a metal atom constituting a dielectric, for example, BaTiO. ₃ Ba and Ti, SrTiO ₃ Sr and Ti, Pb (Ti / Zr) O ₃ Pb, Ti, and Zr.
[0044]
BaTiO, the main dielectric ₃ The method of generating TiO ₂ And BaO or BaCO ₃ Mixed melting, thermal decomposition of barium oxalate titanate, sol-gel method of titanium alkoxide and barium alkoxide, condensation polymerization of titanium hydroxide and barium hydroxide, baking of titanium naphthenate and barium naphthenate, titanium octylate and barium octylate There are various methods such as calcination and hydrothermal synthesis. Therefore, the raw material components of these methods, namely TiO ₂ And BaO or BaCO ₃ The raw material compounds such as barium oxalate titanate, titanium alkoxide and barium alkoxide, titanium hydroxide and barium hydroxide, titanium naphthenate and barium naphthenate, titanium octylate and barium octylate constitute the dielectric precursor 8.
[0045]
If these dielectric precursors 8 are classified, an organic metal compound in which a metal atom and a carbon atom are directly bonded, an organic metal complex in which a ligand is bonded to a metal atom, a higher fatty acid metal salt having viscosity, and the like are included. It is composed of inorganic resin compounds such as metal resinates, metal oxides and metal carbonates.
[0046]
Among these, organometallic resinates are suitable as the dielectric precursor 8 of the present invention. Examples of organometallic resinates include naphthenate, octylate, stearate, oleate, palmitate, laurate, myristate, benzoate, paratoylate, n-decanoate, metal Alkoxides, metal metal acetylacetonates and the like are used.
[0047]
As the organic solvent 10, any solvent that can uniformly disperse the dielectric precursor 8 can be used. For example, alcohol, acetone, propanol, ether, petroleum ether, benzene, ethyl acetate, mineral spirit, other petroleum solvents, terpineol, dihydroterpineol, terpineol acetate, butyl carbitol, cellosolves, aromatics, diethyl phthalate, etc. Can be used. When the dielectric precursor 8 is completely dispersed (dissolved), the solution is colored and transparent.
[0048]
First, in the present invention, an intermediate solution in which the dielectric precursor 8 is uniformly dispersed and dissolved is prepared. After confirming that this solution is in a colored transparent state, it is determined that the dielectric precursor 8 is uniformly dispersed and dissolved in the organic solvent in the molecular state. When an organometallic resinate is used as the dielectric precursor 8, this intermediate solution is referred to as a resinate solution.
[0049]
When the metal fine particles 2 and the dielectric fine particles 6 are uniformly dispersed in the intermediate solution, the intermediate solution develops a metal color peculiar to the metal fine particles 2 depending on the amount of the metal fine particles 2 added. By this metal color spreading evenly throughout the solution, it can be determined that the metal fine particles 2 are uniformly dispersed in the solution.
[0050]
The resin 12 that can be used in the present invention is an organic resin that can adjust the viscosity of the electrode paste 1 and is preferably a material that can uniformly knead the metal fine particles 2, the dielectric fine particles 6, the dielectric precursor 8, and the organic solvent 10. For example, ethyl cellulose, nitrocellulose, butyral, acrylic copay balsam, dammar and the like can be used. Such a resin is kneaded with the solution to give an appropriate viscosity to the electrode paste.
[0051]
In the electrode paste 1, the dielectric powder is added in an amount of 0.1 to 30% by mass with respect to the total amount of the metal powder. If it is 0.1% by mass or less, sintering suppression at a high temperature becomes insufficient, and if it is 30% by mass or more, a problem tends to occur in the conductivity of the electrode film formed by firing the electrode paste. Further, the dielectric precursor 8 is added in an amount of 0.1 to 10% by mass with respect to the total amount of the metal powder. If it is 0.1% by mass or less, sintering suppression at low temperatures is insufficient, and if it is 10% by mass or more, there is a problem in the conductivity of the electrode film. Within these ranges, appropriate amounts of dielectric powder and dielectric precursor 8 are added to the electrode paste 1.
[0052]
FIG. 2 is a process diagram for manufacturing the ceramic electronic component 22 by firing. In (2A), the electrode paste film 16 is formed on the green sheet 14 in a predetermined shape. First, a ceramic powder composed of ceramic fine particles, an organic binder, and an organic solvent are kneaded to form a slurry. The slurry is formed into a sheet shape to form a green sheet 14. An electrode paste film 16 is formed by screen printing the electrode paste 1 on the surface of the green sheet 14.
[0053]
In (2B), organic substances are removed by firing, the green sheet 14 changes to a ceramic substrate 18, and the electrode paste film 16 changes to an electrode film 20. More specifically, in the green sheet 14, all organic substances are removed by firing, and the ceramic fine particles are sintered together to form the ceramic substrate 18. Further, in the electrode paste film 16, all organic substances are removed by firing, and the metal fine particles 2 are sintered together to form a conductive electrode film 20.
[0054]
FIG. 3 is a partially enlarged sectional view of the electrode paste film 16. The large circle represents the metal fine particle 2, the small circle represents the dielectric fine particle 6, and the triangle represents the dielectric precursor 8. In this embodiment, Ni fine particles (Ni-Particle) are used as the metal fine particles 2, and BaTiO 3 is used as the dielectric fine particles 6. ₃ Particles (Powder-Particle), BaTiO as dielectric precursor 8 ₃ Resinate-Particle is used.
[0055]
The dielectric fine particles 6 are interposed between the metal fine particles 2 and 2, whereas the dielectric precursor 8 is dispersed in the three pockets 4 and the fine gaps. The organic solvent 10 and the resin 12 that are not shown are dispersed throughout. It can be considered that when the electrode paste film 16 is fired, the distribution state of FIG. That is, the triangular dielectric precursor 8 is in the distributed state with BaTiO 3. ₃ To change. The dielectric fine particles 6 are also sintered with each other while BaTiO 3 is sintered. ₃ To change. The metal fine particles 2 are sintered together and changed into the electrode film 20 while being subjected to sintering suppression.
[0056]
By removing organic material and sintering, the green sheet 14 shrinks while BaTiO 2 shrinks. ₃ The ceramic substrate 18 becomes. The dielectric fine particles 6 and the dielectric precursor 8 are also BaTiO. ₃ As a result, the electrode film 20 is formed. Ceramic component is BaTiO ₃ Therefore, the firing shrinkage rates of the electrode paste film 16 and the green sheet 14 are close to each other. Accordingly, it is possible to prevent the electrode film 20 from being peeled off from the ceramic substrate 18 or being spheroidized and interrupted in the middle.
[0057]
Supplementing with reference to FIG. 2, a ceramic electronic component 22 is constituted by the electrode film 20 and the ceramic substrate 18. Since there is no peeling of the electrode film 20, the lifetime of the ceramic electronic component 22 can be extended. Further, a plurality of green sheets 14 on which the electrode paste film 16 is formed are stacked, and the whole is fired. As a result, the plurality of green sheets 14 and the electrode paste film 16 are changed to the ceramic substrate 18 and the electrode film 20 by firing, and a multilayer ceramic electronic component is manufactured. The ceramic electronic parts targeted by the present invention include ceramic circuit boards, ceramic capacitors, ceramic inductors, ceramic piezoelectric elements, and ceramic actuators.
[0058]
【Example】
[Example 1: 0.02 μm electrode paste]
Next, specific examples will be described. As the metal powder, a commercially available Ni powder having a particle size of 0.2 μm manufactured by a CVD method was used. The Ni powder was pulverized to obtain a monodispersed Ni powder having an average particle size of 0.2 μm. The pulverization treatment was performed by a wet treatment using n-hexane as a dispersion medium, adjusting the flow rate and the flow length with media mill.
[0059]
As a dielectric powder, BaTiO with a particle size of 0.1 μm ₃ Powder (BT-01 manufactured by Sakai Chemical Industry Co., Ltd.) was added in a variable amount of 0 to 10 mass% with respect to the Ni powder. As a dielectric precursor, BaTiO ₃ The resinate was added in an amount of 1% by mass based on the Ni powder. This BaTiO ₃ The resinate is composed of barium octylate and titanium octylate, which are a kind of organometallic resinates. BaTiO ₃ The reason why the resinate is 1% by mass is that it has been experimentally confirmed that it is the most efficient addition amount when no dielectric powder is added. Of course, BaTiO ₃ It was also confirmed that the resinate was effective when added in the range of 0.1 to 10% by mass. Terpineol was used as the organic solvent for dispersion, and ethylcellulose was used as the viscosity adjusting resin. The composition ratio of all components is shown in Table 2. When Ni powder is 100 mass% (mass%), the mass% of each component is shown.
[0060]
<Table 2> Composition of electrode paste
Ni metal powder (0.2 μm) 100% by mass
BaTiO ₃ Powder (0.1 μm) 0-10% by mass
BaTiO ₃ Resinate 1% by mass
Turpineol 12% by mass
Ethylcellulose 4% by mass
[0061]
BaTiO ₃ Components other than the Ba compound and Ti compound may be added as a resinate. For example, in the first example, barium octylate, magnesium octylate, titanium octylate, zirconium octylate and holmium octylate were mixed so that the metal mass ratio was Ba: Ti = 1.0: 1.0. BaTiO ₃ Resinate. In the second example, barium naphthenate, calcium naphthenate, magnesium naphthenate, titanium naphthenate, zirconium naphthenate, and holmium naphthenate have a metal mass ratio of Ba: Ti: Zr = 0.948: 0.48. : BaTiO mixed to 0.16 ₃ Resinate. Thus, BaTiO ₃ Various resinates can be prepared depending on the purpose.
[0062]
The dry density (green density, Green Density) of the electrode paste thus prepared was measured as follows. An electrode paste film having a thickness of about 200 μm was formed on the pet film using an applicator and dried at 100 ° C. for 1 hour, and then the dried electrode paste film was peeled off from the pet film. This dry electrode paste film was cut into a 20 mm disk shape using a punch, the thickness was measured with a micrometer, and the mass was measured with a precision balance. The green density was calculated from the mass / volume.
[0063]
FIG. 4 shows the density of dry electrode paste film (green density) and BaTiO. ₃ It is a relationship figure with content of powder. The vertical axis is the density of the dry electrode paste film (green density, Green Density), and the horizontal axis is BaTiO. ₃ It is the addition rate (mass%) of the powder. Ni fine particles have a particle size of 0.2 μm, and BaTiO ₃ The amount of resinate added is fixed at 1% by mass.
[0064]
From the graph in this figure, the following situation is estimated. BaTiO ₃ When the addition rate of the powder is 0% by mass, voids are formed between the Ni fine particles, and the green density decreases due to the presence of the voids. When it becomes 5 mass%, the space between the Ni fine particles is BaTiO. ₃ Since it is filled with powder, the green density reaches its maximum. When it becomes 10 mass%, BaTiO ₃ It was found that the green density decreased due to the space between the fine particles.
[0065]
As before, BaTiO with a diameter of 0.1 μm ₃ In the electrode paste in which the dielectric fine particles were mixed, 10% by mass of the dielectric fine particles was added with respect to the amount of Ni metal. On the other hand, in the present invention, the green density reaches the maximum at 5% by mass. ₃ The addition rate of the fine particles can be set to 5% by mass. Therefore, the addition amount of the dielectric is reduced to ½ that of the prior art, the electroconductivity of the electrode film is improved correspondingly, and the waste of the dielectric can be saved.
[0066]
Also, considering the green density before firing, if the content of the dielectric powder is adjusted to a range of 0.1 to 30% by mass with respect to the total amount of the metal powder, it can be used as the electrode paste of the present invention. I understood. That is, the dielectric powder is optimal at 5% by mass, but the dielectric powder can be used in the range of 0.1 to 30% by mass based on the change range of the green density.
[0067]
Next, the electrode paste film was baked to change into an electrode film, and the baking shrinkage rate was measured. The composition of the electrode paste is as shown in Table 2, and BaTiO. ₃ The amount of powder added was adjusted in three ways: 0, 5, 10 (mass%). 97% N of a disk-shaped sample prepared for green density measurement ₂ + 3% H ₂ Placed in a reducing atmosphere. Each sample was fired for 1 hour at a temperature increase rate of 3 ° C. per minute and set to four firing temperatures of 600 ° C., 800 ° C., 1000 ° C., and 1300 ° C.
[0068]
FIG. 5 is a graph showing the relationship between the firing shrinkage rate and firing temperature of an electrode film obtained using the electrode paste (0.2 μm Ni fine particles) of the present invention. The vertical axis represents the firing shrinkage (Shrinkage), and the horizontal axis represents the firing temperature (Temperature). The white circle is BaTiO ₃ Is 0 mass%, triangle is BaTiO ₃ Is 5% by mass, square is BaTiO ₃ Is 10% by mass. The black circle indicates the firing shrinkage rate of the green sheet alone.
[0069]
BaTiO ₃ It was found that the firing shrinkage rate of the electrode paste film decreased as the amount of added increased. When the firing shrinkage rate of the electrode paste film approaches the firing shrinkage rate of the green sheet, peeling of the electrode film does not occur. Judging from the whole graph, BaTiO ₃ When the amount of addition is 10% by mass, it is closest to the shrinkage curve of the green sheet. On the other hand, from the viewpoint of green density, the case of 5% by mass was optimal.
Judging from both firing shrinkage and green density, BaTiO ₃ It can be seen that a powder addition amount in the range of 0.1 to 10 (mass%) is suitable as the electrode paste, and is optimal in a range of 2 to 8 (mass%).
[0070]
FIG. 6 is a scanning electron microscope image at each sintering temperature of the electrode film (0.2 μm Ni fine particles) in the present invention. (6A) is BaTiO ₃ Powder is 0% by mass, (6B) is BaTiO ₃ 5% by mass of powder, (6C) is BaTiO ₃ The case where powder is 10 mass% is shown. In each case, BaTiO ₃ The amount of resinate added is fixed at 1% by mass.
[0071]
BaTiO ₃ When the powder is 0% by mass (6A), BaTiO is used at a firing temperature of 600 ° C. ₃ Sintering inhibition by the resinate is observed. At a firing temperature of 800 ° C., Ni fine particles have started neck growth. Grain growth starts at 1000 ° C., and it is observed that grain growth is remarkable at 1300 ° C. BaTiO ₃ Since no powder was added at all, it is considered that grain growth occurred at a high temperature of 1300 ° C., and the effect of suppressing grain growth was not observed.
[0072]
BaTiO ₃ When the powder is 5% by mass (6B), BaTiO ₃ Resin penetrates between Ni fine particles and suppresses sintering, and BaTiO ₃ Even when the powder is 10% by mass (6C), BaTiO ₃ A sintering suppression effect by the resinate was observed. Even if BaTiO3 powder is added, BaTiO3 ₃ It became clear that the sintering suppression effect by resinate was not diminished. That is, BaTiO ₃ The resinate was proved by an electron microscope to have a sintering inhibiting effect in low-temperature firing.
[0073]
In (6B) and (6C), when the firing temperature reaches 800 ° C and 1000 ° C, BaTiO ₃ It was observed that the powder suppressed the sintering of Ni fine particles. At 1300 ° C, BaTiO ₃ It was observed that the powder sinters and grows, enters between the Ni fine particles, and maintains the sintering suppression effect of the Ni particles. In this way, from the observation of the microstructure of the sintered surface, BaTiO in the low temperature region. ₃ The resinate suppresses sintering, and BaTiO is used at high temperatures. ₃ It has been demonstrated that the powder exhibits sintering suppression.
[0074]
[Example 2: Multilayer ceramic capacitor (electrode paste of Example 1)]
FIG. 7 is a cross-sectional view of a multilayer ceramic capacitor (MLCC) in which 10 layers are laminated using the electrode paste of the present invention. This electrode paste was selected from Example 1, Ni powder having a particle size of 0.2 μm was 100% by mass, BaTiO 3. ₃ 1% by mass of resinate and 0.1 μm particle diameter BaTiO ₃ It was prepared by adding 5% by mass of powder.
[0075]
An electrode paste film was formed on the green sheet by the screen printing method using the electrode paste. The electrode paste film formed in a predetermined pattern has a thickness of 0.7 to 0.9 μm. Ten green sheets were laminated, and the upper and lower surfaces were covered with cover sheets to form a multilayer ceramic capacitor multilayer body.
[0076]
Firing was performed in a state where the laminated body was pressed from above and below. The firing temperature was 1270 ° C. for 2 hours to produce a multilayer ceramic capacitor. This multilayer ceramic capacitor is cut at an appropriate cross section, and a scanning electron microscope image of this cross section is shown in FIG. The film thickness of the electrode film was 0.7 to 0.9 μm. It was found that the electrode film was excellently formed while maintaining a predetermined pattern without causing a peeling phenomenon or an interruption phenomenon. Next, the electrical characteristics of the multilayer ceramic capacitor were measured.
[0077]
FIG. 8 is a measurement diagram of the electric capacity of the multilayer ceramic capacitor. The horizontal line gives the average value of the capacitance, and the vertical line gives the variation range. The measurement was performed with an LCR meter (manufactured by Agilent Technologies). The average value of electric capacity was 38.6 (nF). The maximum value of variation was 41.9 (nF), and the minimum value was 34.8 (nF). It has a sufficient electric capacity as a 10-layer multilayer ceramic capacitor.
[0078]
FIG. 9 is a measurement diagram of the dielectric loss tan δ (%) of the multilayer ceramic capacitor. The horizontal line gives the average value of dielectric loss, and the vertical line gives the variation range. The measurement was performed with an LCR meter (manufactured by Agilent Technologies). The average value of dielectric loss was 2.40%. The maximum value of variation was 2.90%, and the minimum value was 2.26%. It was found that the dielectric loss of the 10-layer multilayer ceramic capacitor was kept below a certain level.
[0079]
FIG. 10 is a measurement diagram of the electric resistance R (Ω) of the multilayer ceramic capacitor. The horizontal line gives the average value of electrical resistance, and the vertical line gives the variation range. The measurement was performed with an insulation resistance meter (manufactured by Agilent Technologies). The average value of electrical resistance is 1.1 × 10 ¹⁰ (Ω), and the maximum variation is 2.8 × 10 ¹⁰ (Ω), the minimum value is 5.6 × 10 ⁹ (Ω). The insulation resistance was sufficient for a 10-layer multilayer ceramic capacitor.
[0080]
[Example 3: 0.1 μm electrode paste]
An electrode paste in which the particle size was changed as compared with Example 1 was prepared. As the metal powder, Ni powder having a particle diameter of 0.1 μm manufactured by a wet reduction method was used. The Ni powder was pulverized to obtain a monodispersed Ni powder having an average particle size of 0.1 μm. The pulverization treatment was performed by a wet treatment using n-hexane as a dispersion medium and adjusting the flow rate and flow length with media mill.
[0081]
As a dielectric powder, BaTiO having a particle size of 0.05 μm ₃ 12% by mass of powder (BT-01 manufactured by Sakai Chemical Industry Co., Ltd.) was added to the Ni powder. As a dielectric precursor, BaTiO ₃ Resinate was added in an amount of 2% by weight based on the Ni powder. This BaTiO ₃ The resinate is composed of barium naphthenate and titanium naphthenate, which are a kind of organometallic resinates. Terpineol was used as the organic solvent for dispersion, and ethylcellulose was used as the viscosity adjusting resin. The composition ratio of all components is shown in Table 3. When Ni powder is 100 mass% (mass%), the mass% of each component is shown.
[0082]
<Table 3> Composition of electrode paste
Ni metal powder (0.1 μm) 100% by mass
BaTiO ₃ Powder (0.05μm) 12% by mass
BaTiO ₃ Resinate 2% by mass
Turpineol 14% by mass
Ethylcellulose 5% by mass
[0083]
[Example 4: Multilayer ceramic capacitor (electrode paste of Example 3)]
FIG. 11 is a cross-sectional view of a multilayer ceramic capacitor (MLCC) in which 10 layers are laminated using the electrode paste of Table 3. This electrode paste is 100% by mass of Ni powder with a particle size of 0.1 μm, BaTiO. ₃ 2% by mass of resinate, 0.05 μm particle size BaTiO ₃ The powder was prepared by adding 15% by mass.
[0084]
An electrode paste film was formed on the green sheet by the screen printing method using the electrode paste. The electrode paste film formed in a predetermined pattern has a thickness of 0.6 to 1.0 μm. Ten green sheets were laminated, and the upper and lower surfaces were covered with cover sheets to form a multilayer ceramic capacitor multilayer body.
[0085]
Firing was performed in a state where the laminated body was pressed from above and below. The firing temperature was 1270 ° C. for 2 hours to produce a multilayer ceramic capacitor. This multilayer ceramic capacitor is cut in an appropriate cross section, and a scanning electron microscope image of this cross section is shown in FIG. The film thickness of the electrode film was 0.6 to 0.8 μm. It was found that the electrode film was excellently formed while maintaining a predetermined pattern without causing a peeling phenomenon or an interruption phenomenon. Next, the electrical characteristics of the multilayer ceramic capacitor were measured.
[0086]
FIG. 12 is a measurement diagram of the capacitance of the multilayer ceramic capacitor. The horizontal line gives the average value of the capacitance, and the vertical line gives the variation range. The average value of electric capacity was 44.0 (nF). The maximum value of variation was 45.9 (nF), and the minimum value was 35.7 (nF). The 10-layer multilayer ceramic capacitor has a sufficient electric capacity.
[0087]
FIG. 13 is a measurement diagram of the dielectric loss tan δ (%) of the multilayer ceramic capacitor. The horizontal line gives the average value of dielectric loss, and the vertical line gives the variation range. The average value of dielectric loss was 2.52%. The maximum variation was 2.79%, and the minimum value was 2.41%. It was found that the dielectric loss of the 10-layer multilayer ceramic capacitor was kept below a certain level.
[0088]
FIG. 14 is a measurement diagram of the electrical resistance R (Ω) of the multilayer ceramic capacitor. The horizontal line gives the average value of electrical resistance, and the vertical line gives the variation range. The average value of electrical resistance is 7.7 × 10 ⁹ (Ω) and the maximum variation is 8.8 × 10 ⁹ (Ω), the minimum value is 7.1 × 10 ⁹ Ω). The insulation resistance was sufficient for a 10-layer multilayer ceramic capacitor.
[0089]
The present invention is not limited to the above-described embodiments and embodiments, but includes various modifications and design changes within the technical scope without departing from the technical idea of the present invention. Not too long.
[0090]
【The invention's effect】
By using the first embodiment of the present invention, an electrode paste can be provided that suppresses high-temperature sintering with dielectric fine particles and suppresses low-temperature sintering with one or more dielectric precursors that form a dielectric by firing, A universal electrode paste capable of suppressing sintering in the entire temperature range can be provided. Therefore, the sintering suppressing effect can be maintained over the entire temperature range with respect to a wide range of temperature changes from low temperature to high temperature received during firing, and there is a dramatic improvement in electrode film characteristics. In addition, when the firing temperature is changed depending on the type of electronic component, that is, the same electrode paste is applied to a ceramic electronic component manufactured by low temperature firing and a ceramic electronic component manufactured by high temperature firing. There is an advantage that can be used. The electronic component industry using the electrode paste can bring about cost reduction and improvement of electrode characteristics.
[0091]
If the 2nd form of this invention is used, a metal powder, dielectric powder, and a dielectric precursor can be disperse | distributed uniformly to an organic solvent, and a solution-form electrode paste can be provided. Depending on the amount of organic solvent added, an electrode paste ranging from a high concentration to a low altitude can be produced. A thick electrode film can be formed with a high concentration electrode paste, and a thin electrode film can be formed with a low concentration electrode paste. In addition, the addition of the organic solvent increases the uniform dispersibility of the components, and the metal density of the electrode film can be made uniform.
[0092]
By using the third embodiment of the present invention, it is possible to provide an electrode paste in which the metal powder, the dielectric powder, and the dielectric precursor are uniformly dispersed in an organic solvent and the viscosity is freely adjusted by adding a resin. A high viscosity electrode paste can be produced if the amount of resin added is large, and a low viscosity electrode paste can be produced if the amount of resin added is small. A high-viscosity electrode paste can be used for a thick film, and a low-viscosity electrode paste can be used for a thin film. Thus, an electrode paste that can freely meet market demands can be realized.
[0093]
If the 4th form of this invention is used, the electrode paste which uses organometallic resinate as a dielectric precursor can be provided. The organometallic resinate is an organometallic resinate, and a higher fatty acid metal salt is a representative substance. The organometallic resinate contains many kinds of metal compounds, and it is extremely easy to change the metal species and the molecular size, and has an advantage that various electrode pastes ranging from noble metals to base metals can be provided.
[0094]
If the 5th form of this invention is used, the electrode paste which prepared the metal content of the dielectric precursor in 0.1-10 mass% with respect to the whole quantity of metal powder can be provided. By changing the metal content of the dielectric precursor within this range, an electrode paste that can adjust the degree of low-temperature sintering suppression while maintaining good conduction characteristics of the electrode film and satisfy the market demands freely There is an advantage that can provide.
[0095]
If the 6th form of this invention is used, the electrode paste prepared in 0.1-30 mass% of content of dielectric powder with respect to the whole quantity of metal powder can be provided. By changing the content of the dielectric powder within this range, it is possible to adjust the degree of suppression of high-temperature sintering while maintaining good conductivity characteristics of the electrode film, and an electrode paste that can freely satisfy various market requirements. There are benefits that can be provided.
[0096]
When the seventh embodiment of the present invention is used, the electrode film can be formed into an ultrathin film by using the smallest possible fine particles as metal fine particles and dielectric fine particles. The downsizing of ceramic electronic parts depends on the reduction in the thickness of the electrode film, and according to the present invention, it is possible to realize super multi-layer and super high density of ceramic electronic parts. Therefore, it is possible to contribute to further miniaturization of electronic devices and personal computers, particularly mobile phones, and to the realization of an advanced mobile society.
[0097]
When the eighth embodiment of the present invention is used, the composition of the dielectric powder and the dielectric precursor is made to coincide with the main component of the dielectric forming the green sheet. The shrinkage rate can be approximated. When the firing shrinkage rate approximates, the electrode film does not peel from the ceramic substrate, and the electrode film does not crack, so that there is an advantage that a dense electrode film having high conduction performance can be formed.
[0098]
By using the ninth aspect of the present invention, it is possible to provide an epoch-making method for manufacturing a ceramic electronic component that can be handled with one electrode paste when the firing temperature is selected according to the type of the ceramic electronic component. Unlike the prior art, since many types of electrode pastes are not prepared for each firing temperature, it is possible to contribute to the reduction of the manufacturing cost of the ceramic electronic component. Examples of the ceramic electronic component include a ceramic circuit board, a ceramic capacitor, a ceramic inductor, a ceramic piezoelectric element, and a ceramic actuator. In addition, there is an advantage that the present invention can be used in a method for manufacturing a new ceramic electronic component that will appear in the future.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view of an electrode paste 1 according to the present invention.
FIG. 2 is a process diagram for manufacturing a ceramic electronic component 22 by firing.
FIG. 3 is a partially enlarged cross-sectional view of an electrode paste film 16;
FIG. 4 shows the density of dry electrode paste film (green density) and BaTiO. ₃ It is a relationship figure with content of powder.
FIG. 5 is a graph showing the relationship between the firing shrinkage rate and the firing temperature of an electrode film obtained using the electrode paste (0.2 μm Ni fine particles) of the present invention.
FIG. 6 is a scanning electron microscope image at each sintering temperature of an electrode film (0.2 μm Ni fine particles) in the present invention.
FIG. 7 is a cross-sectional view of a multilayer ceramic capacitor (MLCC) in which 10 layers are laminated using the electrode paste of the present invention.
FIG. 8 is a measurement diagram of electric capacity of a multilayer ceramic capacitor.
FIG. 9 is a measurement diagram of dielectric loss tan δ (%) of a multilayer ceramic capacitor.
FIG. 10 is a measurement diagram of electric resistance R (Ω) of a multilayer ceramic capacitor.
11 is a cross-sectional view of a multilayer ceramic capacitor (MLCC) in which 10 layers are laminated using the electrode paste of Table 3. FIG.
12 is a measurement diagram of electric capacity of a multilayer ceramic capacitor using the electrode paste of Table 3. FIG.
13 is a measurement diagram of dielectric loss tan δ (%) of a multilayer ceramic capacitor using the electrode paste of Table 3. FIG.
14 is a measurement diagram of electrical resistance R (Ω) of a multilayer ceramic capacitor using the electrode paste of Table 3. FIG.
FIG. 15 is a schematic diagram for explaining a relationship between a metal fine particle diameter D and a three pocket diameter d.
[Explanation of symbols]
1 Electrode paste
2 Metal fine particles
3 containers
4 Three pockets
6 Dielectric particles
8 Dielectric precursor
10 Organic solvent
12 Resin
14 Green sheet
16 Electrode paste film
18 Ceramic substrate
20 Electrode membrane
22 Ceramic electronic parts

Claims (9)

An electrode paste comprising at least a metal powder, one or more dielectric precursors that form a dielectric by firing, and a dielectric powder. An electrode paste comprising at least a metal powder, one or more dielectric precursors that form a dielectric by firing, a dielectric powder, and an organic solvent that uniformly disperses these substances. It contains a metal powder, one or more dielectric precursors that form a dielectric upon firing, a dielectric powder, an organic solvent that uniformly disperses these substances, and a viscosity adjusting resin. Electrode paste. The electrode paste according to claim 12 or 3, wherein the dielectric precursor is an organometallic resinate. The electrode paste according to claim 1, wherein the metal content of the dielectric precursor is 0.1 to 10% by mass with respect to the total amount of the metal powder. The electrode paste according to claim 1, 2, or 3, wherein the content of the dielectric powder is 0.1 to 30% by mass with respect to the total amount of the metal powder. 2. The average particle size of metal fine particles constituting the metal powder is 0.1 to 0.5 μm, and the average particle size of dielectric fine particles constituting the dielectric powder is 0.05 to 0.3 μm. 2. The electrode paste according to 2 or 3. The electrode paste according to claim 1, 2 or 3, wherein the composition of the dielectric precursor and the dielectric powder are configured to match the main component of the dielectric forming the green sheet. An electrode paste film is formed on a green sheet using the electrode paste according to claim 1, 2, 3, 4, 5, 6, 7 or 8, and the green sheet and the electrode paste film are integrally fired. A method for producing a ceramic electronic component, comprising removing an organic component and forming an electrode film having a desired pattern on a ceramic substrate by firing.

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