Conductive pastes, electronic components, and multilayer ceramic capacitors

Abstract

This invention provides a conductive paste that exhibits minimal viscosity changes over time, slow shrinkage during the sintering process, and the ability to suppress cracking during the sintering process. [Solution] A conductive paste comprising conductive powder, ceramic powder, a dispersant, a binder resin, and an organic solvent, wherein the dispersant comprises at least one titanate organometallic compound.

Description

Technical Field

[0001] The present disclosure relates to a conductive paste, an electronic component, and a multilayer ceramic capacitor. In particular, the present disclosure relates to a conductor constituting an electronic component, particularly a conductive paste used for forming an internal electrode of a multilayer ceramic capacitor, and an electronic component having a conductor formed using this conductive paste or a multilayer ceramic capacitor provided with an internal electrode.

Background Art

[0002] With the miniaturization and high performance of electronic devices such as mobile phones and digital devices, miniaturization and high capacitance are desired for electronic components including multilayer ceramic capacitors. A multilayer ceramic capacitor has a structure in which a plurality of dielectric layers and a plurality of internal electrode layers are alternately laminated, and it is possible to achieve its miniaturization and high capacitance by thinning these dielectric layers and internal electrode layers.

[0003] A multilayer ceramic capacitor is manufactured, for example, as follows. First, a conductive paste for an internal electrode is printed on the surface of a dielectric green sheet containing a dielectric powder such as barium titanate (BaTiO3) and a binder resin in a predetermined electrode pattern and dried to form a dry film. Next, a laminate is obtained by laminating the dry film and the green sheet alternately so as to overlap. Next, this laminate is heat-bonded and integrated to form a bonded body. This bonded body is cut, and after performing a debinding process in an oxidizing atmosphere or an inert atmosphere, firing is performed to obtain a fired chip. Then, an external electrode paste is applied to both ends of the fired chip, and after firing, nickel plating or the like is applied to the surface of the external electrode to obtain a multilayer ceramic capacitor.

[0004] Generally, conductive pastes used to form internal electrode layers contain conductive powder, ceramic powder, binder resin, and organic solvents. Conductive pastes may also contain dispersants to improve the dispersibility of conductive powders. With the recent trend towards thinner internal electrode layers, conductive powders tend to have smaller particle sizes. When conductive powder particles are small, the specific surface area of ​​the particle surface increases, leading to higher surface activity of the conductive powder (metal powder), which can result in decreased dispersibility and reduced viscosity properties.

[0005] For this reason, attempts have been made to improve the viscosity characteristics of conductive pastes over time. For example, Japanese Patent Publication No. 2015-216244 discloses a conductive paste containing at least a metal component, an oxide, a dispersant, and a binder resin, wherein the metal component is Ni powder having a specific composition ratio for its surface composition, the acidity site of the dispersant is 500 to 2000 μmol / g, and the acidity site of the binder resin is 15 to 100 μmol / g. With this configuration, this conductive paste is said to have good dispersibility and viscosity stability.

[0006] Furthermore, Japanese Patent Publication No. 2013-149457 discloses a conductive paste for internal electrodes comprising a conductive powder, a resin, an organic solvent, a ceramic powder mainly composed of barium titanate (TiBaO3), and an agglomeration inhibitor, wherein the agglomeration inhibitor content is 0.1% by weight or more and 5% by weight or less, and the agglomeration inhibitor is a tertiary amine or secondary amine represented by a specific structural formula. This conductive paste for internal electrodes is said to suppress the agglomeration of the co-material components, have excellent long-term storage properties, and enable the thinning of multilayer ceramic capacitors.

[0007] On the other hand, in order to thin the internal electrode layer, it is required that the density of the dried film obtained by printing a conductive paste for the internal electrode onto the surface of the derivative green sheet and drying it be high. For example, Japanese Patent Publication No. 2006-063441 proposes a metal ultrafine powder slurry containing an organic solvent, a surfactant, and metal ultrafine particles, wherein the surfactant is oleoyl sarcosine, the metal ultrafine powder slurry contains 70% to 95% by mass of the metal ultrafine powder, and the surfactant is contained in an amount of more than 0.05 parts by mass and less than 2.0 parts by mass per 100 parts by mass of the metal ultrafine powder. In this metal ultrafine powder slurry, aggregation of ultrafine particles is prevented and no aggregated particles are present, so it is said to have excellent dispersibility and dried film density. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2015-216244 [Patent Document 2] Japanese Patent Publication No. 2013-149457 [Patent Document 3] Japanese Patent Publication No. 2006-063441 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] However, with the recent trend towards thinner electrode patterns, conductive pastes are required to exhibit further improvements in viscosity characteristics over time.

[0010] In light of these circumstances, this disclosure aims to provide a conductive paste that exhibits minimal viscosity changes over time. [Means for solving the problem]

[0011] A conductive paste according to one aspect of the present disclosure comprises conductive powder, ceramic powder, a dispersant, a binder resin, and an organic solvent. The dispersant is characterized by containing at least one phosphorus-containing titanate organometallic compound.

[0012] Preferably, the phosphorus-containing titanate organometallic compound includes at least one of bis(dioctyl pyrophosphate) oxyacetate titanate, tetraoctylbis(ditridecyl phosphite) titanate, or tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl) phosphite titanate.

[0013] Preferably, the dispersant contains the phosphorus-containing titanate organometallic compound in an amount of 0.01 parts by mass to 2 parts by mass per 100 parts by mass of the conductive powder, and the conductive powder is contained in an amount of 40% by mass to 60% by mass of the entire conductive paste.

[0014] The dispersant is preferably contained in an amount of 0.01% by mass or more and 3% by mass or less relative to the entire conductive paste.

[0015] The conductive powder preferably contains at least one metal powder selected from Ni, Pd, Pt, Au, Ag, Cu, or alloys thereof.

[0016] The conductive powder preferably has an average particle size of 0.05 μm or more and 1.0 μm or less.

[0017] The ceramic powder preferably contains a perovskite-type oxide.

[0018] An electronic component according to one aspect of the present disclosure is characterized in that it includes at least a conductor, the conductor being formed using a conductive paste according to one aspect of the present disclosure.

[0019] A multilayer ceramic capacitor according to one aspect of the present disclosure comprises at least a laminate in which a dielectric layer and an internal electrode layer are stacked, and the internal electrode layer is formed using a conductive paste according to one aspect of the present disclosure. [Effects of the Invention]

[0020] According to one aspect of the present disclosure, it is possible to provide a conductive paste with little viscosity change over time.

[0021] Therefore, by using the conductive paste of one aspect of the present disclosure, it is possible to further thin the electrode pattern including the conductor of the electronic component or the internal electrode of the multilayer ceramic capacitor, and it is possible to improve the productivity thereof.

Brief Description of the Drawings

[0022] [Figure 1] Using the dry films of the conductive pastes obtained in the examples and comparative examples of the present disclosure, pellets with a diameter of 0.5 cm and a height of 0.15 cm were produced, and using a thermomechanical analyzer (manufactured by Rigaku Corporation, TMA8311), in a hydrogen-nitrogen mixed gas atmosphere, when the temperature was raised from room temperature to 1300 °C at 5 °C / min., it is a graph showing the amount of dimensional change at each temperature with the dimension at 50 °C as the reference value. [Figure 2] FIG. 2 is a perspective view (FIG. 2A) and a cross-sectional view (FIG. 2B) showing a multilayer ceramic capacitor as an example of an embodiment of the present disclosure.

Modes for Carrying Out the Invention

[0023] [Conductive Paste] An example of the conductive paste of one embodiment of the present disclosure includes a conductive powder, a ceramic powder, a dispersant, a binder resin, and an organic solvent, and is characterized in that the dispersant contains a phosphorus-containing titanate organometallic compound.

[0024] Hereinafter, each component constituting the conductive paste of this example will be described in detail.

[0025] (Conductive Powder) The conductive powder is not particularly limited, and any metal powder applicable to the conductive paste application can be used. For example, at least one metal powder selected from Ni, Pd, Pt, Au, Ag, Cu, or alloys thereof can be used as the conductive powder.

[0026] Among these, metal powder made of Ni or a Ni alloy is preferred from the viewpoint of conductivity, corrosion resistance, and cost. As the Ni alloy, for example, an alloy of Ni with at least one element selected from the group consisting of Mn, Cr, Co, Al, Fe, Cu, Zn, Ag, Au, Pt, or Pd can be used. The Ni content in the Ni alloy is, for example, 50% by mass or more, preferably 80% by mass or more, based on the total conductive powder. The metal powder made of Ni or a Ni alloy may contain several hundred ppm of sulfur to suppress rapid gas generation due to partial thermal decomposition of the binder resin during the debindering process.

[0027] The average particle size of the conductive powder is preferably 0.05 μm to 1.0 μm, and more preferably 0.1 μm to 0.5 μm. When the average particle size of the conductive powder is within the above range, it can be suitably used as a conductive paste for the internal electrodes of thin-film multilayer ceramic capacitors, and for example, it is possible to improve the smoothness and density of the dried film.

[0028] The average particle size is a value obtained from observations using a scanning electron microscope (SEM). It is the average value obtained by measuring the particle size of multiple particles from images observed with an SEM at a magnification of 10,000x.

[0029] The conductive powder content is preferably 30% by mass or more and less than 70% by mass, and more preferably 40% by mass or more and 60% by mass or less, relative to the total conductive paste. When the conductive powder content is within the above range, the conductivity and dispersibility are excellent.

[0030] (Ceramic powder) The ceramic powder is not particularly limited, and for example, in the case of a conductive paste for the internal electrodes of a multilayer ceramic capacitor, it is appropriately selected from known ceramic powders depending on the type of multilayer ceramic capacitor to be applied. Examples of ceramic powders include perovskite-type oxides containing Ba and Ti, and barium titanate (BaTiO3) is preferred.

[0031] As the ceramic powder, a ceramic powder mainly composed of barium titanate and containing oxides as minor components may be used. Examples of oxides include oxides of Mn, Cr, Si, Ca, Ba, Mg, V, W, Ta, Nb, or one or more rare earth elements. Alternatively, as the ceramic powder, a perovskite-type oxide ferroelectric ceramic powder may be used in which the Ba or Ti atoms of barium titanate (BaTiO3) are substituted with other atoms, such as Sn, Pb, or Zr.

[0032] In conductive paste for internal electrodes, a ceramic powder with the same composition as the dielectric ceramic powder constituting the green sheet of a multilayer ceramic capacitor can be used as the ceramic powder. This suppresses crack generation due to a mismatch in shrinkage at the interface between the dielectric layer and the internal electrode layer during the sintering process. Examples of such ceramic powders include oxides of ZnO, ferrite, PZT, BaO, Al2O3, Bi2O3, R(rare earth element)2O3, and TiO2. One type of ceramic powder may be used, or two or more types may be used.

[0033] The average particle size of the ceramic powder is, for example, 0.01 μm or more and 0.5 μm or less, preferably in the range of 0.01 μm or more and 0.3 μm or less. Because the average particle size of the ceramic powder is within this range, when used as a conductive paste for internal electrodes, it is possible to form sufficiently fine, thin, and uniform internal electrodes.

[0034] The average particle size is a value obtained from observations using a scanning electron microscope (SEM). It is the average value obtained by measuring the particle size of multiple particles from images observed with an SEM at a magnification of 50,000x.

[0035] The ceramic powder content is preferably 1 to 30 parts by mass, and more preferably 3 to 30 parts by mass, per 100 parts by mass of conductive powder.

[0036] The ceramic powder content is preferably 1% to 20% by mass, and more preferably 3% to 20% by mass, relative to the total conductive paste. When the ceramic powder content is within the above range, the conductivity and dispersibility are excellent.

[0037] (Binder resin) The binder resin is not particularly limited, and any known resin can be used. Examples of binder resins include cellulosic resins such as methylcellulose, ethylcellulose, ethylhydroxyethylcellulose, and nitrocellulose, acrylic resins, and butyral resins such as polyvinyl butyral.

[0038] From the viewpoint of solubility in solvents and combustion decomposition properties, the binder resin preferably contains ethyl cellulose.

[0039] When used as a conductive paste for internal electrodes, the binder resin preferably contains butyral resin to improve adhesion strength with the green sheet, or butyral resin may be used alone as the binder resin.

[0040] The binder resin may be of one type or of two or more types. For example, both a cellulose-based resin and a butyral resin may be used as the binder resin. The molecular weight of the binder resin can be, for example, around 20,000 to 200,000.

[0041] The binder resin content is preferably 1 to 10 parts by mass, and more preferably 1 to 8 parts by mass, per 100 parts by mass of conductive powder.

[0042] The binder resin content is preferably 0.5% by mass or more and 10% by mass or less, and more preferably 1% by mass or more and 6% by mass or less, relative to the total conductive paste.

[0043] When the binder resin content is within the above range, it exhibits excellent conductivity and dispersibility.

[0044] (Organic solvents) The organic solvent is not particularly limited, and any known organic solvent capable of dissolving the binder resin can be used. Examples of organic solvents include acetate-based solvents such as dihydroterpinyl acetate, isobornyl acetate, isobornyl propinate, isobornyl butyrate, isobornyl isobutyrate, ethylene glycol monobutyl ether acetate, and dipropylene glycol methyl ether acetate; terpene-based solvents such as terpineol and dihydroterpineol; and hydrocarbon-based solvents such as tridecane, nonane, and cyclohexane. One type of organic solvent may be used, or two or more types may be used.

[0045] The content of the organic solvent is preferably 40 parts by mass or more and 100 parts by mass or less, and more preferably 65 parts by mass or more and 95 parts by mass or less, per 100 parts by mass of conductive powder.

[0046] The content of the organic solvent is preferably 20% by mass or more and 60% by mass or less, and more preferably 35% by mass or more and 55% by mass or less, relative to the entire conductive paste.

[0047] When the content of the organic solvent is within the above range, it exhibits excellent conductivity and dispersibility.

[0048] (Dispersant: Phosphorus-containing titanate organometallic compound) The conductive paste in this example contains at least one phosphorus-containing titanate organometallic compound as a dispersant. The inclusion of a phosphorus-containing titanate organometallic compound helps maintain the dispersion of the conductive powder in the conductive paste, thereby reducing the viscosity change of the conductive paste over time.

[0049] Phosphorus-containing titanate organometallic compounds include at least one of the following: bis(dioctyl pyrophosphate)oxyacetate titanate represented by formula (1), tetraoctylbis(ditridecyl phosphite) titanate represented by formula (2), or tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate represented by formula (3).

[0050] [ka]

[0051] [ka]

[0052] [ka]

[0053] By adding a phosphorus-containing titanate organometallic compound as a dispersant to a conductive paste, it is thought that the lone pairs of electrons in the titanate group donate electrons to the surface of the metal particles, resulting in a coordinate bond structure. Therefore, the phosphorus-containing titanate organometallic compound can efficiently adsorb to the surface of the metal particles and form a coordinate bond. Furthermore, the steric hindrance caused by its functional groups is thought to affect the adsorption to the metal particles constituting the conductive powder, thereby improving the stability of the viscosity of the conductive paste over time.

[0054] The conductive paste contains a phosphorus-containing titanate organometallic compound in an amount of 0.01 parts by mass to 2 parts by mass, preferably 0.02 parts by mass to 1 part by mass, per 100 parts by mass of conductive powder. When the phosphorus-containing titanate organometallic compound is contained within the above range, changes in viscosity over time can be suppressed and viscosity stability can be improved. However, if the content of the phosphorus-containing titanate organometallic compound exceeds 2 parts by mass, the viscosity of the paste may decrease significantly when printed on a green sheet.

[0055] Furthermore, the conductive paste may contain dispersants other than phosphorus-containing titanate organometallic compounds, to the extent that they do not impair the effects of the present invention. Other dispersants may include, for example, acidic dispersants containing higher fatty acids and polymeric surfactants, cationic dispersants other than acidic dispersants, nonionic dispersants, amphoteric surfactants, and polymeric dispersants. These dispersants may also be used individually or in combination of two or more.

[0056] In this case, the dispersant is contained in an amount of 0.01 parts by mass to 3 parts by mass, preferably 0.02 parts by mass to 2 parts by mass, per 100 parts by mass of conductive powder.

[0057] (Properties of conductive paste) The conductive paste in this example, by containing the above-mentioned components, maintains the dispersion state of the conductive powder in the conductive paste and reduces the change in viscosity of the conductive paste over time.

[0058] The viscosity of the conductive paste, when measured 24 hours after manufacture, preferably has a viscosity change of 13 days after manufacture (14 days after manufacture) within the range of -5 Pa·s to +10 Pa·s. The viscosity of the conductive paste can be measured, for example, using a rheometer. In this case, the shear rate dependence (flow curve) measurement is performed at a rotation speed of 4 sec. -1 It is preferable to measure under these conditions.

[0059] The viscosity change is more preferably in the range of -1 Pa·s to +5 Pa·s, and even more preferably in the range of greater than -1 Pa·s and less than +2 Pa·s.

[0060] Furthermore, by including the above-mentioned components, the conductive paste in this example maintains the dispersion state of the conductive powder in the conductive paste and allows for appropriate control of the sintering of the conductive powder.

[0061] The sintering behavior (shrinkage behavior) can be determined by preparing a predetermined pellet using a dried film of conductive paste and observing the dimensional change between 750°C and 800°C using a thermomechanical analyzer under predetermined conditions, for example, under a hydrogen-nitrogen mixed gas atmosphere, when the temperature is raised from room temperature to 1300°C at a rate of 5°C / min.

[0062] If rapid shrinkage occurs near this temperature, the sintering shrinkage behavior of the internal electrode layer and the dielectric layer (green sheet) becomes mismatched, resulting in the internal electrode layer being composed of an electrode film with low continuity. The conductive paste in this example prevents such rapid shrinkage behavior and exhibits a tendency toward gradual shrinkage. Therefore, the sintering shrinkage behavior of the internal electrode layer and the dielectric layer (green sheet) can be matched, making it possible to construct the internal electrode layer as an electrode film with high continuity.

[0063] (Method for manufacturing conductive paste) The method for manufacturing the conductive paste in this example is not particularly limited, and known methods can be used. The conductive paste can be manufactured, for example, by preparing each of the above components and stirring and kneading them using a three-roll mill, ball mill, mixer, etc.

[0064] In this process, applying a dispersant to the surface of the conductive powder beforehand allows the conductive powder to loosen sufficiently without agglomerating, enabling the dispersant to spread evenly across the surface and making it easier to obtain a uniform conductive paste.

[0065] Alternatively, a binder resin can be dissolved in an organic solvent for the vehicle to prepare an organic vehicle, and then conductive powder, ceramic powder, the organic vehicle, and a dispersant can be added to an organic solvent for the paste, and the mixture can be stirred and kneaded in a mixer to prepare a conductive paste.

[0066] [Multilayer ceramic capacitor (electronic component)] An example of a conductive paste according to one embodiment of the present disclosure can be suitably applied to the formation of conductors in electronic components, particularly the internal electrode layer of a multilayer ceramic capacitor having at least a laminate in which a dielectric layer and an internal electrode layer are stacked.

[0067] Examples of conductors in electronic components include electrodes that make up passive components such as resistors, inductors, and capacitors; wiring and electrodes in ceramic substrates, printed circuit boards, solar cells, and touch panels; and conductive adhesives used when mounting electronic components onto substrates.

[0068] The conductive paste in this example is particularly suitable for forming the internal electrode layer of a multilayer ceramic capacitor. Therefore, the structure and manufacturing method of a multilayer ceramic capacitor will be described below with reference to the drawings. In the drawings, schematic representations and changes in scale may be used as appropriate. The position and orientation of components will be described with reference to the XYZ Cartesian coordinate system shown in Figure 2, etc., as appropriate. In this XYZ Cartesian coordinate system, the X and Y directions are horizontal, and the Z direction is vertical (up and down).

[0069] Figure 2 (Figures 2A and 2B) schematically shows the structure of the multilayer ceramic capacitor 1. The multilayer ceramic capacitor 1 comprises a ceramic laminate 10 in which dielectric layers 12 and internal electrode layers 11 are alternately stacked, and an external electrode 20.

[0070] (1) To manufacture a multilayer ceramic capacitor 1 with such a structure using the conductive paste of this example, first, the conductive paste is printed onto a dielectric layer made of a ceramic green sheet, dried, and a dried film is formed.

[0071] More specifically, an unfired ceramic sheet, known as a ceramic green sheet, is prepared. Examples of this ceramic green sheet include a dielectric layer paste obtained by adding an organic binder such as polyvinyl butyral and a solvent such as terpineol to a predetermined ceramic raw material powder, such as barium titanate. This paste is then applied in a sheet-like manner to a support film such as a PET film, dried, and the solvent removed. The thickness of the dielectric layer made from the ceramic green sheet is not particularly limited, but from the viewpoint of miniaturizing multilayer ceramic capacitors, it is preferably between 0.05 μm and 3 μm.

[0072] Next, several sheets of this ceramic green sheet are prepared by printing (coating) the conductive paste of this example onto one side of the sheet using a known method such as screen printing, drying it, and forming a dried film. It is preferable that the thickness of the conductive paste (dried film) after printing be 1 μm or less after drying, from the viewpoint of thinning the internal electrode layer 11.

[0073] (2) A plurality of dielectric layers having a dried film on the upper surface are laminated by compression to obtain a laminate, and then the laminate is fired to integrate them, thereby producing a ceramic laminate 10 in which the internal electrode layer 11 and the dielectric layer 12 are alternately laminated.

[0074] More specifically, the ceramic green sheet is peeled from the support film, and then the dielectric layer made of the ceramic green sheet and the dried film formed on one side thereof are laminated alternately. After that, a laminate is obtained by heating and pressurizing. In addition, a configuration in which protective ceramic green sheets without conductive paste are further arranged on both sides of the laminate is also possible.

[0075] Next, the laminate is cut to a predetermined size to form green chips, and then the green chips are subjected to a debinder treatment and fired in a reducing atmosphere to produce the ceramic laminate 10. The atmosphere used for the debinder treatment is preferably air or an N2 gas atmosphere. The temperature used for the debinder treatment is, for example, 200°C to 400°C. Furthermore, it is preferable to maintain this temperature for 0.5 hours to 24 hours during the debinder treatment.

[0076] The firing process is carried out in a reducing atmosphere to suppress oxidation of the metal used in the internal electrode layer. The firing temperature of the laminate is, for example, between 1000°C and 1350°C, and the holding time during firing is, for example, between 0.5 hours and 8 hours.

[0077] By firing the green chips, the organic binder in the green sheet is completely removed, and the ceramic raw material powder is fired to form a ceramic dielectric layer 12. In addition, the organic vehicle in the dried film is removed, and the conductive powder (for example, nickel powder or nickel-based alloy powder) is sintered or melted and integrated to form internal electrodes, thus forming a laminated ceramic fired body in which multiple dielectric layers 12 and internal electrode layers 11 are alternately stacked.

[0078] Furthermore, annealing treatment may be applied to the multilayer ceramic sintered body after firing, from the viewpoint of incorporating oxygen into the dielectric layer to improve reliability and suppressing re-oxidation of the internal electrodes.

[0079] (3) Subsequently, a multilayer ceramic capacitor 1 is manufactured by forming a pair of external electrodes 20 on both ends of the ceramic laminate 10.

[0080] For example, the external electrode 20 comprises an external electrode layer 21 and a plating layer 22. The external electrode layer 21 is electrically connected to the internal electrode layer 11. Suitable materials for the external electrode 20 include, for example, copper, nickel, or alloys thereof.

[0081] In the multilayer ceramic capacitor of this example, it is preferable that the dielectric ceramic powder contained in the dielectric green sheet and the ceramic powder contained in the conductive paste are powders of the same composition. In the multilayer ceramic capacitor manufactured using the conductive paste of this example, sheet attack and peeling defects of the green sheet are suppressed even when the thickness of the dielectric green sheet is, for example, 3 μm or less. [Examples]

[0082] The present disclosure will be described in detail below based on examples and comparative examples, but the present disclosure is not limited in any way by the following examples.

[0083] [Evaluation Method] (Evaluation of the viscosity of conductive paste) Flow curve measurements were performed using a rheometer (Anton Paar M501 rheometer) at a shear rate of 4 seconds. -1 The value was defined as the viscosity of the conductive paste. The value of the conductive paste 24 hours after manufacturing was used as the reference viscosity, and after standing at room temperature (25°C) for 14 days after manufacturing, the flow curve was measured again. Then, the change in viscosity was calculated by subtracting the reference viscosity from the viscosity value after 14 days.

[0084] (Sintering behavior) Using the dried conductive paste films obtained in the examples and comparative examples, pellets with a diameter of 0.5 cm and a height of 0.15 cm were prepared. These pellets were then heated from room temperature to 1300°C at a rate of 5°C / min. under a hydrogen-nitrogen gas mixture atmosphere using a thermomechanical analyzer (Rigaku Corporation, TMA8311). The dimensional change at 750°C was calculated, with the dimensions at 50°C used as the baseline.

[0085] [Materials used] Excluding the phosphorus-containing titanate organometallic compound used as a dispersant, the following materials were used as constituent materials (conductive powder, ceramic powder, binder resin, and organic solvent) of the conductive paste.

[0086] (conductive powder) Nickel (Ni) powder (SEM average particle size 0.2 μm) was used as the conductive powder.

[0087] (Ceramic powder) Barium titanate (BaTiO3) powder (SEM average particle size 0.06 μm) was used as the ceramic powder.

[0088] (Binder resin) Ethyl cellulose resin and polyvinyl butyral resin (PVB resin) were used as binder resins. The binder resins were prepared as vehicles dissolved in dihydroterpineol.

[0089] (Organic solvents) Dihydroterpineol was used as the organic solvent.

[0090] [Example 1] As the phosphorus-containing titanate organometallic compound constituting the dispersant, bis(dioctyl pyrophosphate) oxyacetate titanate was used. This bis(dioctyl pyrophosphate) oxyacetate titanate is a type of phosphorus-containing titanate organometallic compound represented by formula (1).

[0091] A conductive paste was prepared by mixing 50% by mass of conductive (nickel) powder, 3.8% by mass of ceramic powder, 3% by mass of binder resin in a vehicle consisting of ethylcellulose resin and polyvinyl butyral resin, 0.5% by mass of bis(dioctyl pyrophosphate) oxyacetate titanate, and 100% by mass of terpineol.

[0092] [Example 2] A conductive paste was prepared and evaluated in the same manner as in Example 1, except that tetraoctylbis(ditridecylphosphite) titanate was used as the phosphorus-containing titanate organometallic compound. Tetraoctylbis(ditridecylphosphite) titanate is a type of phosphorus-containing titanate organometallic compound represented by formula (2).

[0093] [Example 3] A conductive paste was prepared and evaluated in the same manner as in Example 1, except that tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate was used as the phosphorus-containing titanate organometallic compound. Tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate is a type of phosphorus-containing titanate organometallic compound represented by formula (3).

[0094] [Comparative Example 1] A conductive paste was prepared and evaluated in the same manner as in Example 1, except that a dispersant was not added.

[0095] [Comparative Example 2] A conductive paste was prepared and evaluated in the same manner as in Example 1, except that isopropyl titanium triisostearate was used as a dispersant instead of a phosphorus-containing titanate organometallic compound.

[0096] [Comparative Example 3] A conductive paste was prepared and evaluated in the same manner as in Example 1, except that bis[2-[(2-aminoethyl)amino]ethanolate][2-[2-aminoethyl]amino]ethanolate-O](propane-2-oleate)titanate was used as a dispersant instead of a phosphorus-containing titanate organometallic compound.

[0097] Table 1 shows the titanate organometallic compounds used in Examples 1-3 and Comparative Examples 1-3 (for Examples 1-3, phosphorus-containing titanate organometallic compounds having a specific structure), as well as the change in viscosity of the conductive paste, for each example.

[0098] [Table 1]

[0099] (Evaluation results) The conductive pastes of Examples 1 to 3, which contained phosphorus-containing titanate organometallic compounds, showed significantly smaller changes in viscosity after 14 days of standing compared to the conductive paste of Comparative Example 1, which did not contain phosphorus-containing titanate organometallic compounds, and also compared to the conductive pastes of Comparative Examples 2 and 3, which used titanate organometallic compounds other than phosphorus-containing titanate organometallic compounds.

[0100] Furthermore, as shown in Figure 1, the rapid shrinkage behavior around 800°C observed in Comparative Example 1 was less pronounced in the conductive pastes of Examples 1 to 3, demonstrating that crack suppression is possible for multilayer ceramic capacitors. Thus, the conductive paste according to one embodiment of the present disclosure exhibits gradual shrinkage during the sintering process and can suppress cracks during the sintering process. [Explanation of Symbols]

[0101] 1. Multilayer ceramic capacitor 10 Ceramic Laminate 11 Internal electrode layer 12 Dielectric layer 20 External electrode 21 External electrode layer 22 Plating layer

Claims

1. A conductive paste comprising conductive powder, ceramic powder, dispersant, binder resin, and organic solvent, A conductive paste wherein the dispersant comprises at least one phosphorus-containing titanate organometallic compound.

2. The conductive paste according to claim 1, wherein the phosphorus-containing titanate organometallic compound comprises at least one of bis(dioctyl pyrophosphate) oxyacetate titanate, tetraoctylbis(ditridecyl phosphite) titanate, or tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl) phosphite titanate.

3. The conductive paste according to claim 1, wherein the dispersant contains 0.01 parts by mass or more and 2 parts by mass or less of the phosphorus-containing titanate organometallic compound per 100 parts by mass of the conductive powder, and the conductive powder is contained in an amount of 40% by mass or more and 60% by mass or less of the entire conductive paste.

4. The conductive paste according to claim 1, wherein the dispersant is contained in an amount of 0.01% by mass or more and 3% by mass or less with respect to the entire conductive paste.

5. The conductive paste according to claim 1, wherein the conductive powder comprises at least one metal powder selected from Ni, Pd, Pt, Au, Ag, Cu, or alloys thereof.

6. The conductive paste according to claim 1, wherein the conductive powder has an average particle size of 0.05 μm or more and 1.0 μm or less.

7. The conductive paste according to claim 1, wherein the ceramic powder comprises a perovskite-type oxide.

8. An electronic component comprising at least a conductor, wherein the conductor is formed using a conductive paste according to any one of claims 1 to 7.

9. A multilayer ceramic capacitor having at least a laminate in which a dielectric layer and an internal electrode layer are stacked, wherein the internal electrode layer is formed using the conductive paste described in any one of claims 1 to 7.

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