Glass powder, conductive paste, and method for producing multilayer ceramic capacitor

Abstract

To provide general-purpose glass powder and associated techniques ensuring sufficient adhesion performance to multilayer chips constituting various multilayer ceramic capacitors.SOLUTION: Glass powder disclosed herein is used in a conductive paste. The glass powder contains, in terms of oxide-equivalent mass ratios, the following components: SiO2: 6 wt.% to 18 wt.%; B2O3: 18 wt.% to 30 wt.%; ZnO: 26 wt.% to 47 wt.%; Al2O3: 2 wt.% to 17 wt.%; and CaO: 10 wt.% to 25 wt.%, and is substantially free from BaO.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing glass powder, conductive paste, and multilayer ceramic capacitors.

Background Art

[0002] In recent years, multilayer ceramic electronic components such as multilayer ceramic capacitors (MLCC), multilayer inductors, and multilayer piezoelectric elements (multilayer varistors) have been used in a wide range of fields. For example, an MLCC has a laminated chip in which dielectric layers containing a ceramic material and internal electrode layers containing a conductive material are alternately laminated. And external electrodes are formed on the outside (for example, the side surface) of the laminated chip to connect to each of the plurality of internal electrode layers. This external electrode is formed, for example, by firing a conductive paste containing conductive particles and glass powder.

[0003] In the external electrode, from the viewpoint of conduction reliability, adhesion performance to the laminated chip is required. In this regard, Patent Document 1 discloses a glassy frit in which the ratio of each element constituting the glass is set to a predetermined ratio in terms of oxide conversion, and a conductive composition for a ceramic capacitor terminal electrode dispersed in an organic vehicle.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in recent years, with the increasing demand for multilayer ceramic capacitors, various performances such as higher capacitance and temperature characteristics have been required. Therefore, the multilayer chips that make up the multilayer ceramic capacitors are also diversified depending on the main components. Accordingly, in the conductive paste for external electrode applications, adhesive performance for a wide range of materials is required.

[0006] The technology disclosed herein was created in view of such points, and aims to provide a general-purpose glass powder that can obtain sufficient adhesive performance for the multilayer chips that make up various multilayer ceramic capacitors. Further, as another aspect, it aims to provide a conductive paste containing the glass powder and a method for manufacturing a multilayer ceramic capacitor using the conductive paste.

Means for Solving the Problems

[0007] The glass powder disclosed herein is a glass powder used in a conductive paste, and the glass powder has the following composition in terms of mass ratio in terms of oxide: SiO2: 6 wt% to 18 wt%; B2O3: 18 wt% to 30 wt%; ZnO: 26 wt% to 47 wt%; Al2O3: 2 wt% to 17 wt%; CaO: 10 wt% to 25 wt%; and is characterized by substantially not containing BaO.

[0008] In the above glass powder, the mass ratio of the glass powder is controlled as described above in terms of oxide. Thereby, it was confirmed that when the glass powder melts and forms an external electrode, sufficient adhesiveness between the external electrode and the multilayer chip can be obtained. Further, according to the inventor's intensive study, it was found that when BaO is contained in the glass powder, the adhesive performance to the multilayer chip deteriorates. Therefore, the above glass powder substantially does not contain BaO. Thereby, a decrease in the adhesive performance to the multilayer chip can be suppressed.

[0009] In a preferred aspect of the glass powder disclosed herein, the glass powder substantially does not contain alkaline earth metal oxides other than CaO.

[0010] In a preferred embodiment of the glass powder disclosed herein, the softening point of the glass powder is 500°C or higher and 650°C or lower.

[0011] In a preferred embodiment of the glass powder disclosed herein, the median diameter D 50 of the glass powder is 1 μm or more and 3 μm or less.

[0012] In a preferred embodiment of the glass powder disclosed herein, the glass powder contains 20 wt% or more of B2O3 in terms of mass ratio in terms of oxide.

[0013] In a preferred embodiment of the glass powder disclosed herein, the glass powder contains 10 wt% or more of Al2O3 in terms of mass ratio in terms of oxide.

[0014] Also, as another aspect of the technology disclosed herein, a conductive paste containing the glass powder of the present disclosure, conductive particles, and a dispersion medium is provided. Thereby, when the above conductive paste is fired, sufficient adhesiveness with the multilayer chip can be obtained.

[0015] In a preferred embodiment of the conductive paste disclosed herein, the above conductive particles are Cu particles.

[0016] In a preferred embodiment of the conductive paste disclosed herein, when the entire conductive paste is 100 wt%, the above glass powder is contained in an amount of 4 wt% or more and 12 wt% or less.

[0017] Furthermore, as another aspect of the technology disclosed herein, a method for manufacturing a multilayer ceramic capacitor is provided. The method for manufacturing a multilayer ceramic capacitor disclosed herein includes a multilayer chip preparation step of preparing a multilayer chip, a paste application step of applying the conductive paste prepared in the above paste preparation step to the surface of the multilayer chip prepared in the above multilayer chip preparation step, and a firing step of firing the multilayer chip to which the conductive paste is applied. Here, the glass powder has the following composition in terms of mass ratio in terms of oxide: SiO2: 6 wt% to 18 wt%; B2O3: 18 wt% to 30 wt%; ZnO: 26 wt% to 47 wt%; Al2O3: 2 wt% to 17 wt%; CaO: 10 wt% to 25 wt%; and substantially free of BaO. Thereby, a multilayer ceramic capacitor with sufficient adhesion performance between the multilayer chip and the external electrode can be obtained.

[0018] In a preferred embodiment of the method for manufacturing a multilayer ceramic capacitor disclosed herein, the multilayer chip includes a dielectric layer mainly composed of a perovskite-type oxide.

[0019] In a preferred embodiment of the method for manufacturing a multilayer ceramic capacitor disclosed herein, as the perovskite-type oxide, it includes (CaSr)(TiZr)O3.

[0020] In a preferred embodiment of the method for manufacturing a multilayer ceramic capacitor disclosed herein, the firing step is performed at a firing temperature of 650 °C or higher and 850 °C or lower.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0022] Hereinafter, preferred embodiments of the technology disclosed herein will be described. Matters other than those specifically mentioned in this specification and necessary for the implementation of the technology disclosed herein can be understood as design matters of those skilled in the art based on the prior art in the relevant field. The technology disclosed herein can be implemented based on the content disclosed in this specification and the common general knowledge in the relevant field. Note that the notation "A~B" indicating a numerical range in this specification means "A or more and B or less".

[0023] [Glass powder] The glass powder disclosed herein is used for conductive paste applications. The glass powder of the present disclosure melts during paste firing to become a liquid glass component. And this liquid glass component fills the gaps in the sintered body of the conductive particles to densify the external electrodes and has the function of imparting adhesion performance. And the glass powder disclosed herein is characterized by containing the following composition in terms of mass ratio in terms of oxide and substantially not containing BaO. Hereinafter, the glass powder disclosed herein will be described. SiO2: 6 wt% to 18 wt%; B2O3: 18 wt% to 30 wt%; ZnO: 26 wt% to 47 wt%; Al2O3: 2 wt% to 17 wt%; CaO: 10 wt% to 25 wt%;

[0024] (1) Composition of the glass powder In this section, the specific composition of the glass powder disclosed herein will be described.

[0025] (a) Silicon oxide (SiO2) SiO2 is one of the components (glass skeleton components) that can form a glass skeleton alone. As the proportion of SiO2 in this glass skeleton component increases, the thermal stability of the glass powder improves. In addition, SiO2 also has the function of enhancing the chemical resistance of the glass powder. From this perspective, in the technology disclosed herein, the content ratio of SiO2 in the glass powder is set to 6 wt% or more. From the viewpoints of the thermal stability and chemical resistance of the glass powder, the content ratio of SiO2 is preferably 7.5 wt% or more, and more preferably 10 wt% or more. On the other hand, from the perspective that the viscosity becomes too high during melting as the content ratio increases, in the technology disclosed herein, the content ratio of SiO2 in the glass powder is set to 18 wt% or less. From this perspective, the content ratio of SiO2 in the glass powder is preferably 16.5 wt% or less, and more preferably 12 wt% or less.

[0026] (b) Boron oxide (B2O3) B2O3 is one of the glass skeleton components. That is, the glass powder disclosed herein is a borosilicate glass containing SiO2 and B2O3 in the glass skeleton. In this borosilicate glass, as the proportion of B2O3 in the glass skeleton increases, the fluidity of the glass component after melting tends to improve, resulting in sufficient adhesion performance. From this perspective, in the technology disclosed herein, the content ratio of B2O3 in the glass powder is set to 18 wt% or more. From the perspective of further improving the fluidity of the glass component, the content ratio of B2O3 is preferably 20 wt% or more, more preferably 23 wt% or more, and particularly preferably 24 wt% or more. On the other hand, if the proportion of B2O3 becomes too high, the fluidity of the glass component may increase too much, and the glass may ooze out onto the electrode surface. As a result, the metal component may be coated, which may inhibit conduction. Therefore, in the technology disclosed herein, the upper limit of the content ratio of B2O3 is set to 30 wt% or less. From the perspective of conduction reliability, the content ratio of B2O3 in the glass powder is preferably 27 wt% or less, and preferably 25 wt% or less.

[0027] (c) Zinc oxide (ZnO) ZnO is a component capable of modifying the glass skeleton (glass skeleton modifying component). This ZnO has the functions of enhancing the meltability of the glass and adjusting the viscosity of the glass components during firing, as well as improving water resistance, thermal shock resistance, etc. In the technology disclosed herein, from the perspective of improving water resistance, thermal shock resistance, etc., the content ratio of ZnO in the glass powder is set to 26 wt% or more. Note that from the perspective of improving water resistance, thermal shock resistance, etc., the content ratio of ZnO in the glass powder is preferably 32 wt% or more, more preferably 35 wt% or more, and particularly preferably 40 wt% or more. Thereby, an external electrode with even better durability can be formed. On the other hand, from the perspective of suppressing a decrease in adhesion performance due to excessive increase in the fluidity of the glass component, the upper limit of the content ratio of ZnO is set to 47 wt% or less. Note that from the perspective of suppressing a decrease in adhesion performance, the content ratio of ZnO in the glass powder is preferably 45 wt% or less, more preferably 43 wt% or less, and particularly preferably 41 wt% or less.

[0028] (d) Aluminum oxide (Al2O3) Al2O3 has the function of stabilizing the glass skeleton and contributes to the chemical resistance and adhesion performance of the external electrode after firing. In the technology disclosed herein, from the perspective of imparting general-purpose adhesion performance by the external electrode after firing, the content ratio of Al2O3 in the glass powder is set to 2 wt% or more. Note that from the perspective of forming an external electrode with more general-purpose adhesion performance, the content ratio of Al2O3 in the glass powder is preferably 2 wt% or more, more preferably 8 wt% or more, and particularly preferably 10 wt% or more. On the other hand, when the content ratio of Al2O3 in the glass powder increases, the fluidity of the glass components during firing decreases, and the adhesion performance tends to decrease. For this reason, from the perspective of causing sufficient fluidity in the glass components at the initial stage of firing, the upper limit of the content ratio of Al2O3 is set to 17 wt% or less. Note that from the perspective of more suitably improving the fluidity of the glass components at the initial stage of firing, the content ratio of Al2O3 is preferably 15 wt% or less, more preferably 14 wt% or less, and particularly preferably 12 wt% or less.

[0029] (e) Calcium oxide (CaO) CaO is a glass framework modifying component and has the function of reducing the viscosity of the glass component after melting. That is, when the glass powder containing CaO is fired, a highly fluid glass component that easily diffuses throughout the external electrode is produced. This greatly improves the denseness of the external electrode after firing and can contribute to sufficient adhesion performance of the glass powder. In addition to the above-described function, CaO also has the function of improving chemical resistance and abrasion resistance. In the technology disclosed herein, the content ratio of CaO in the glass powder is preferably 10 wt% or more, more preferably 11 wt% or more, and particularly preferably 15 wt% or more. On the other hand, when the content ratio of CaO in the glass powder increases, there is a tendency for the adhesion performance to decrease due to the excessive increase in the fluidity of the glass component. From the viewpoint of more preferably suppressing the decrease in adhesion performance, the content ratio of CaO is preferably 25 wt% or less, more preferably 24 wt% or less, and particularly preferably 20 wt% or less.

[0030] (f) Barium oxide (BaO) The glass powder disclosed herein is characterized by substantially not containing barium oxide (BaO). Glass powder containing a large amount of BaO tends to have a large coefficient of thermal expansion, so there is a risk of a decrease in adhesive force. Therefore, the glass powder according to the present disclosure substantially does not contain barium oxide (BaO). Note that "substantially not containing BaO" in this specification means that BaO is not intentionally added. Therefore, when a component that can be interpreted as BaO is contained in trace amounts derived from raw materials, manufacturing processes, etc., it is included in the concept of "substantially not containing BaO" in this specification. For example, when the content of BaO in the glass powder is 0.01 wt% or less (preferably 0.005 wt% or less, more preferably 0.001 wt% or less, still more preferably 0.0005 wt% or less, and particularly preferably 0.0001 wt% or less), it can be said that "substantially not containing BaO".

[0031] (g) Alkaline earth metal oxides Alkaline earth metal oxides other than calcium oxide (CaO) may cause a decrease in the adhesion to glass powder, although their effects are smaller compared to barium oxide. Therefore, in some preferred embodiments, the glass powder disclosed herein preferably substantially does not contain alkaline earth metal oxides other than calcium oxide. Here, examples of the "alkaline earth metal oxides other than calcium oxide" in this specification include magnesium oxide (MgO) and strontium oxide (SrO). Note that the phrase "substantially does not contain alkaline earth metal oxides other than calcium oxide" in this specification means that alkaline earth metal oxides other than calcium oxide are not intentionally added. Therefore, when components that can be interpreted as alkaline earth metal oxides other than calcium oxide are contained in trace amounts due to raw materials, manufacturing processes, etc., they are included in the concept of "substantially does not contain alkaline earth metal oxides other than calcium oxide" in this specification. For example, when the content of alkaline earth metal oxides (excluding calcium oxide) in the glass powder is 0.1 wt% or less (preferably 0.05 wt% or less, more preferably 0.01 wt% or less, still more preferably 0.005 wt% or less, and particularly preferably 0.001 wt% or less), it can be said that "substantially does not contain alkaline earth metal oxides other than calcium oxide".

[0032] (h) Other components Note that the above description is not intended to limit the composition of the glass powder disclosed herein to the above-described components. The glass powder disclosed herein may contain P2O5, Bi2O3, etc. as glass skeleton components other than SiO2 and B2O3. Further, as glass skeleton modifying components, components other than BaO, such as Li2O, Na2O, K2O, TiO2, MnO, FeO, Fe2O3, Fe3O4, SnO, SnO2, V2O5, ZrO2, Nb2O5, CuO, Cu2O, La2O3, CeO2, etc. may be contained. Although not limiting the technology disclosed herein, the total content ratio of these metal oxides is preferably 10 wt% or less, more preferably 7 wt% or less, still more preferably 5 wt% or less, and particularly preferably 3 wt% or less.

[0033] (2) Shape, etc. of glass powder Next, the content regarding the shape, etc. of the glass powder will be described.

[0034] (a) Median diameter Although not limiting the technology disclosed herein, the median diameter D of the glass powder 50 is preferably 10 μm or less, more preferably 7 μm or less, still more preferably 5 μm or less, and particularly preferably 3 μm or less. As the median diameter D of the glass powder 50 becomes smaller, the glass powder is more likely to melt during paste firing, so there is a tendency to sufficiently exhibit the adhesion performance. On the other hand, if the median diameter D of the glass powder 50 becomes too small, the inorganic particles (conductive particles, glass powder) in the paste tend to aggregate with each other, and the paste viscosity is likely to increase. From such a viewpoint, the median diameter D of the glass powder 50 is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 0.7 μm or more, and particularly preferably 1 μm or more. In addition, considering the adhesion performance of the external electrode after firing, the median diameter of the glass powder is preferably smaller than the median diameter of the conductive particles. Thereby, since the fine glass powder is arranged in the gaps between the coarse conductive particles, the glass component is likely to be filled in the gaps of the sintered body of the conductive particles during firing.

[0035] (b) Aspect ratio Next, the shape of the glass powder is not particularly limited. The glass powder may be spherical or non-spherical (for example, rugby ball shape, columnar, needle-like, etc.). From the viewpoint of suppressing the increase in the viscosity of the paste, the glass powder is preferably spherical or substantially spherical. For example, the average aspect ratio of the glass powder is typically 1 to 2, preferably 1 to 1.5.

[0036] (c) Softening point Further, the softening point of the glass powder is preferably 650°C or lower, more preferably 630°C or lower, still more preferably 610°C or lower, and particularly preferably 600°C or lower. This can produce a glass component with suitable fluidity even in low-temperature firing, thus contributing to the adhesion performance of the external electrode after firing. On the other hand, from the perspective of suppressing a decrease in adhesion performance due to excessive increase in the fluidity of the glass component, the softening point of the glass powder is preferably 500°C or higher, more preferably 520°C or higher, and particularly preferably 540°C or higher. Note that the "softening point" in this specification is the temperature at which the glass begins to soften and deform under its own weight. Typically, the softening point can be the "temperature at which the glass viscosity is about 10 7.6 dPa·s" measured in accordance with JIS R 3103-1(2001).

[0037] [Conductive Paste] As another aspect of the technology disclosed herein, a conductive paste is provided. The conductive paste of the present disclosure contains at least conductive particles, the glass powder having the above configuration, and a dispersion medium. Hereinafter, each component of the conductive paste disclosed herein will be described.

[0038] 1. Conductive Particles The conductive particles are the main component material of the external electrode after firing. For these conductive particles, metal particles having desired conductivity can be used without particular limitation. As an example of such conductive particles, single metals such as nickel (Ni), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), copper (Cu), ruthenium (Ru), rhodium (Rh), osmium (Os), iridium (Ir), aluminum (Al), tungsten (W), etc., and alloys containing these metals can be mentioned. Also, the conductive particles may be used alone with any one of the above-described metal materials, or in combination of two or more. Among the above-described conductive particles, Cu particles are particularly suitable as the main component of the external electrode because they are inexpensive and have suitable conductivity.

[0039] In addition, the content of the conductive particles in the conductive paste is not particularly limited and can be appropriately adjusted as needed. From the perspective of improving the electrical conductivity of the external electrode after firing, the content of the conductive particles is preferably 60 wt% or more, more preferably 65 wt% or more, and even more preferably 70 wt% or more. On the other hand, from the perspective of ensuring a certain amount or more of the glass powder content to sufficiently obtain the adhesiveness of the external electrode, the upper limit of the content of the conductive particles is preferably 90 wt% or less, more preferably 85 wt% or less, and even more preferably 80 wt% or less. In addition, the "content" in this specification means the mass ratio when the total mass of the conductive paste is 100 wt% unless otherwise specified.

[0040] Also, the particle size of the conductive particles is not particularly limited, and particle sizes that can be adopted in the field of conductive pastes can be applied without particular limitation. For example, the median diameter of the conductive particles may be 0.1 μm or more, 0.25 μm or more, 0.5 μm or more, or 1 μm or more. Also, the median diameter of the conductive particles may be 50 μm or less, 25 μm or less, or 10 μm or less. In addition, the "median diameter" in this specification is the particle diameter (equivalent volume sphere diameter) corresponding to 50% of the cumulative value from the smaller side of the particle diameter in the volume-based particle size distribution based on the laser diffraction scattering method.

[0041] Incidentally, the shape of the conductive particles is not particularly limited. For example, the shape of the conductive particles may be spherical or non-spherical. The non-spherical shape may be, for example, plate-like, scaly, flaky, irregular, or the like. From the viewpoint of facilitating an increase in the packing density of the conductive particles, as the spherical conductive particles, those having an aspect ratio of 1.2 or less, preferably 1.15 or less, for example 1.1 or less, can be preferably used. Further, from the viewpoint of facilitating an increase in the contact area of the conductive particles, as the non-spherical conductive particles, those having an aspect ratio exceeding 1.2, preferably 1.3 or more, 1.5 or more, for example 1.7 or more, and more preferably 2 or more, may be used. From the viewpoint of multiplying the above effects, the conductive particles may be a mixture of spherical and non-spherical ones. Thereby, when the solvent is removed from the paste by drying, a plurality of conductive particles can preferably come into contact with each other, and the electrical conductivity of the conductive film can be enhanced. Incidentally, the "average aspect ratio" in this specification is calculated based on electron microscope observation. Specifically, the aspect ratio is the ratio (b / a) of the length of the long side (b) to the length of the short side (a) when a rectangle circumscribing the particles is drawn in an electron micrograph. And the average aspect ratio is the arithmetic mean value of the aspect ratios obtained for 100 particles.

[0042] The content of the glass powder in the conductive paste is preferably adjusted as appropriate according to need. Incidentally, as the content of the glass powder increases, the adhesion performance of the external electrode after firing can be preferably obtained. From such a viewpoint, when the total mass of the conductive paste is 100 wt%, the content of the glass powder is preferably 4 wt% or more, more preferably 6 wt% or more, and even more preferably 7.5 wt% or more. On the other hand, considering suppressing a decrease in adhesion performance due to glass floating, the upper limit of the content of the glass powder is preferably 12 wt% or less, and more preferably 10 wt% or less.

[0043] 3. Dispersing medium The dispersion medium is a liquid medium for dispersing the above-mentioned powder materials (such as conductive particles, glass powder, etc.). The detailed components of such a dispersion medium are not particularly limited, and conventionally known dispersion media that can be used in the preparation of the conductive paste can be used. Further, since the dispersion medium is a component premised on disappearing by drying and firing, it preferably has a boiling point of about 150°C or higher and 300°C or lower (for example, about 170°C or higher and 270°C or lower).

[0044] Incidentally, as an example of the dispersion medium, an organic dispersion medium (non-aqueous dispersion medium) can be mentioned. As an example of such an organic dispersion medium, alcohol solvents such as methanol, sclarole, citronellol, phytol, geranyl linalool, texanol, benzyl alcohol, phenoxyethanol, 1-phenoxy-2-propanol, terpineol, dihydroterpineol, isoborneol, butyl carbitol, and diethylene glycol; ester solvents such as terpineol acetate, dihydroterpineol acetate, isobornyl acetate, carbitol acetate, and diethylene glycol monobutyl ether acetate; and mineral spirit, etc. Among these, alcohol solvents (for example, dihydroterpineol) can be preferably used.

[0045] Incidentally, the content ratio of the dispersion medium is preferably adjusted appropriately in consideration of the workability when applying the conductive paste. Since such workability during paste application can vary depending on the application means, the content ratio of the dispersion medium is not limited to a specific numerical value. As an example, when screen printing is adopted as the application means, the content of the dispersion medium can be adjusted within the range of 5 wt% to 20 wt% (preferably 10 wt% to 15 wt%).

[0046] 4. Other Additives In addition, the conductive paste disclosed herein can be used without particular limitation for conventionally known additives that can be used in this type of conductive paste, as long as the effects (adhesion performance) of the technology disclosed herein are not significantly impaired. For example, the conductive paste may contain a binder, a dispersant, a thickener, a plasticizer, a pH adjuster, a stabilizer, a leveling agent, an antifoaming agent, an antioxidant, a sintering aid, a preservative, a coloring agent (pigment, dye, etc.), and the like.

[0047] For example, a binder is an additive that contributes to the fixing property when the paste is applied to a laminated chip and to the improvement of the binding property between conductive particles. Also, like the dispersion medium, the binder is preferably a material that disappears during firing. Therefore, the binder is preferably an organic binder (typically, an organic compound having a burnout temperature of 500°C or lower). The specific components of the binder in the conductive paste disclosed herein are not particularly limited, and conventionally known binders can be used without particular limitation. Examples of such binders include organic polymer compounds such as rosin-based resins, cellulose-based resins, polyvinyl alcohol-based resins, polyvinyl acetal-based resins, acrylic-based resins, urethane-based resins, epoxy-based resins, phenol-based resins, polyester-based resins, and ethylene-based resins. Although it cannot be generally stated as it depends on the combination with the above-mentioned dispersion medium, among these organic compounds, cellulose-based resins, polyvinyl alcohol-based resins, polyvinyl acetal-based resins, acrylic-based resins, etc. are suitable as binders. The binder may be used alone with any one of the above-mentioned organic compounds, or in combination of two or more. Also, the binder may be a copolymer or a block copolymer obtained by copolymerizing these organic compounds. Note that the content of the binder is preferably appropriately adjusted so that suitable fixing property can be exhibited. For example, the content of the binder is preferably 1 wt% or more, more preferably 1.5 wt% or more, further preferably 2 wt% or more, and particularly preferably 2.5 wt% or more. On the other hand, from the viewpoint of preventing binder residue after firing, the content of the binder is preferably 10 wt% or less, more preferably 9 wt% or less, further preferably 8 wt% or less, and particularly preferably 7.5 wt% or less.

[0048] Also, the dispersant is an additive that suppresses the aggregation of inorganic particles (such as conductive particles and glass powder) in the paste. Specifically, the dispersant has a function of stabilizing the solid-liquid interface between the inorganic particles and the dispersion medium and preventing the aggregation of the inorganic particles. Therefore, the glass powder in the paste can be uniformly dispersed, and the adhesion performance of the glass powder can be more preferably exhibited. Note that the type of the dispersant and the like are not particularly limited, and a conventionally known dispersant can be appropriately selected as needed. As an example of such a dispersant, an anionic dispersant can be mentioned. Since the anionic dispersant has excellent adsorption power to inorganic particles, the inorganic particles can be appropriately dispersed over a long period of time. As such an anionic dispersant, a carboxylic acid-based dispersant can be mentioned. Specific examples of such a carboxylic acid-based dispersant include stearic acid, oleic acid, myristic acid, palmitic acid, linoleic acid, lauric acid, linolenic acid, and the like. Note that the conductive paste may also contain two or more types of dispersants. The content of such a dispersant is preferably adjusted within the range of 0.05 wt% to 5 wt% (preferably 0.1 wt% to 1 wt%, more preferably 0.1 wt% to 0.5 wt%).

[0049] [Uses of Conductive Paste] As described above, the conductive paste disclosed herein has been described. The conductive paste having the above configuration is used in the manufacture of multilayer ceramic electronic components such as multilayer ceramic capacitors (MLCCs), and is preferably used as an external electrode paste for forming external electrodes of the multilayer ceramic electronic components.

[0050] [Multilayer Ceramic Capacitor (MLCC)] Hereinafter, as an example of the use of the conductive paste disclosed herein, a multilayer ceramic capacitor (MLCC) will be described. FIG. 1 is a cross-sectional schematic diagram schematically explaining the configuration of an MLCC. As shown in FIG. 1, the multilayer ceramic capacitor (MLCC) 1 typically includes a multilayer chip 10 and external electrodes 40 formed on a pair of opposing end faces of the multilayer chip 10.

[0051] The multilayer chip 10 has a plurality of internal electrode layers 30 laminated via a dielectric layer 20. In an actual MLCC, the bonding boundaries between the dielectric layers 20 are integrated to the extent that they are not visible. Such a multilayer chip 10 is formed by applying a conductive paste, which is a precursor of the internal electrode layer 30, onto the surface of a ceramic green sheet, which is a precursor of the dielectric layer 20, and then simultaneously drying and firing them. Here, a part of the internal electrode layer 30 is exposed at the end faces (the left and right ends in FIG. 1) of the multilayer chip 10.

[0052] The dielectric layer 20 is typically composed of a sintered laminate (ceramic substrate) of ceramic green sheets containing a ceramic dielectric. The dielectric layer 20 can appropriately use one or more types selected from various ceramic dielectrics in a conventionally known MLCC according to applications and the like. Here, in some preferred embodiments, a dielectric layer 20 containing a perovskite-type oxide as a main component can be preferably employed. Note that the "perovskite-type oxide" in this specification has a composition represented by the general formula ABO3. Here, A in the formula represents an element occupying the A site of the perovskite crystal structure, and B in the formula represents an element occupying the B site of the perovskite crystal structure. Also, in this specification, the main component refers to the component having the highest content ratio in the entire dielectric layer 20. Typically, the main component occupies 50 mass% or more of the dielectric layer 20, preferably occupies 70 mass% or more, and more preferably occupies 90 mass% or more.

[0053] Examples of perovskite-type oxides include BaTiO3 (barium titanate), (CaSr)(TiZr)O3 (hereinafter also referred to as "CSTZ"), SrTiO3 (strontium titanate), CaTiO3 (calcium titanate), MgTiO3 (magnesium titanate), (Bi 1 / 2 Na 1 / 2 )TiO3 (bismuth sodium titanate, BNT), Pb(Zr x Ti 1―x )O3 (lead zirconate titanate, PZT), TiZnO3 (zinc titanate), Ba(Mg 1 / 3 Nb 2 / 3)Examples include O3 (magnesium niobate barium titanate), CaZrO3 (calcium zirconate), Ba(ZrTi)O3 (barium zirconate titanate, BZT), etc. Among them, as perovskite-type oxides, barium titanate or CSTZ can be preferably adopted, and CSTZ can be more preferably adopted.

[0054] However, the constituent components of the dielectric layer 20 are not limited to this, and components other than perovskite-type oxide components, for example, TiO2 (titanium dioxide, rutile), Ti3O5 (titanium pentoxide), HfO2 (hafnium oxide), ZrO (zirconium oxide), Al2O3 (aluminum oxide), 2MgO·SiO2 (forsterite), NbO (niobium oxide), BaNd2Ti5O 14 (barium neodymium titanate), and other metal oxides such as rare earth element oxides may also be used.

[0055] It is known to those skilled in the art that generally, due to the influence of environmental temperature, atmosphere, etc., oxygen deficiency, etc. occurs for charge compensation in the perovskite-type crystal structure, and ionic conductivity is exhibited. At this time, assuming the oxygen deficiency amount is δ, the perovskite-type crystal structure can be represented by the general formula ABO 3-δ and δ typically satisfies 0≦δ≦1. In the technology disclosed herein, such a composition deviation in the oxide having a perovskite-type crystal structure is naturally allowed. Similarly, the perovskite-type crystal structure is known to be robust against chemical solid solution and allows partial substitution by ions of different valences and sizes. For example, it is also known that the ratio of the A-site element to the B-site element can deviate from 1:1. In this specification, within the scope not departing from the essence of the technology disclosed herein, it is not limited to the ratio of the A-site element to the B-site element being exactly 1:1. For example, it is allowed for the ratio of the A-site element to the B-site element to deviate by about 1:0.95 to 1.05 (typically about 1:0.98 to 1.02).

[0056] Note that the internal electrode layer 30 in FIG. 1 can adopt the structure and materials in a conventionally known MLCC without particular limitation, and since it is not an element that limits the technology disclosed herein, a detailed description thereof is omitted.

[0057] In this MLCC 1, a pair of external electrodes 40 are provided on the side surface of the stacked chip 10 composed of the dielectric layer 20 and the internal electrode layer 30. As an example, the internal electrode layer 30 is connected to different external electrodes 40 alternately in the stacking order. Thereby, a small-sized and large-capacity MLCC is constructed in which capacitor structures each composed of the dielectric layer 20 and a pair of internal electrode layers 30 sandwiching the dielectric layer 20 are connected in parallel. Although not shown, a metal plating layer is formed on the surface of the external electrode 40.

[0058] Incidentally, in the MLCC 1, in order to maintain the conduction reliability between the internal electrode layer 30 and the external electrode 40, adhesiveness between the external electrode 40 and the stacked chip 10 (more specifically, between the external electrode 40 and the dielectric layer 20) is required. And the external electrode 40 of this MLCC 1 is formed by firing the conductive paste disclosed herein. As described above, the external electrode 40 formed using the conductive paste disclosed herein has excellent adhesiveness. For this reason, an MLCC 1 with high conduction reliability in which the external electrode 40 and the stacked chip 10 are firmly adhered (joined) can be obtained.

[0059] As an example of the use of the conductive paste containing the glass powder disclosed herein, MLCC has been described. Note that the use of the conductive paste containing the glass powder disclosed herein is not limited to the above-described MLCC. Other examples of multilayer ceramic electronic components in which the conductive paste containing the glass powder disclosed herein can be used include multilayer inductors, multilayer piezoelectric elements (multilayer varistors), and the like. In these electronic components as well, adhesion performance between the external electrode and the multilayer chip may be required. On the other hand, according to the conductive paste containing the glass powder disclosed herein, sufficient adhesion performance of the external electrode can be contributed. Therefore, by using the conductive paste containing the glass powder disclosed herein, highly reliable conductive multilayer inductors, multilayer varistors, and the like can be manufactured.

[0060] [Method for manufacturing multilayer ceramic capacitor] As another aspect of the technology disclosed herein, a method for manufacturing a multilayer ceramic capacitor (MLCC) is provided. Such a manufacturing method includes at least a paste preparation step, a paste application step, and a firing step. In the method for manufacturing an MLCC disclosed herein, in addition to the above steps, other steps may be further included at any stage, and the other manufacturing processes may be the same as those in the prior art.

[0061] 1. Paste preparation step In this step, a conductive paste containing glass powder, conductive particles, and a dispersion medium is prepared. The glass powder of the conductive paste prepared in this step is characterized by containing the following composition in terms of mass ratio in terms of oxide and substantially not containing BaO. Thereby, an external electrode having versatile adhesion performance can be stably formed. SiO2: 6 wt% - 18 wt%; B2O3: 18 wt% - 30 wt%; ZnO: 26 wt% - 47 wt%; Al2O3: 2 wt% - 17 wt%; CaO: 10 wt% - 25 wt%;

[0062] The conductive paste prepared in this step may have the above-described configuration except that it contains the glass powder of the above-described composition. Since it has already been described, duplicate explanations are omitted.

[0063] When preparing the conductive paste in this step, conductive particles and glass powder may be added to a dispersion medium and stirred using a conventionally known stirring and mixing device (for example, a roll mill, a magnetic stirrer, a planetary mixer, a disper, etc.).

[0064] 2. Multilayer Chip Preparation Step In this step, the multilayer chip 10 which is the main body of the MLCC1 is prepared. When preparing the multilayer chip 10 in this step, for example, first, a ceramic green sheet as a base material is prepared. In one example, a ceramic material as a dielectric material, a binder, an organic solvent, etc. are stirred and mixed to prepare a paste for forming a dielectric layer. Next, the prepared paste is spread on a carrier sheet by the doctor blade method or the like, and a plurality of unfired ceramic green sheets are formed. On the plurality of formed ceramic green sheets, a conductor film is formed so as to have a desired thickness (for example, in the sub-micron to micron level) in a predetermined pattern. This conductor film is a portion that becomes the internal electrode layer after firing. After creating a plurality of (for example, several hundred to several thousand) unfired ceramic green sheets with conductor films in this way, these are laminated and pressure-bonded. Thereby, an unfired multilayer chip is produced.

[0065] Next, the unfired multilayer chip produced above is fired under appropriate heating conditions (for example, a temperature of about 1000 to 1300°C). Thereby, the multilayer chip is simultaneously fired (baked) and integrally sintered. As described above, a multilayer chip 10 in which a large number of dielectric layers 20 and internal electrode layers 30 are alternately laminated can be obtained. However, this step is not limited to such means, and it can also be prepared by obtaining a pre-fired multilayer chip.

[0066] The multilayer chip 10 prepared in this project can use one that includes a dielectric layer used in the conventionally known MLCC as described above. In some embodiments, a multilayer chip including a dielectric layer mainly composed of a perovskite-type oxide can be preferably employed. Since the conductive paste of the present disclosure contains glass powder having the above-described composition, an external electrode 40 having sufficient adhesion performance with respect to the multilayer chip 10 is formed in the subsequent firing process. Therefore, even when the multilayer chip 10 including a dielectric layer mainly composed of a perovskite-type oxide is employed, the MLCC1 having excellent conduction reliability in which the external electrode 40 and the multilayer chip 10 are adhered with sufficient strength can be provided. Note that as the dielectric layer mainly composed of a perovskite-type oxide, barium titanate or CSTZ can be preferably employed, and CSTZ can be more preferably employed.

[0067] 3. Paste Coating Step In this step, the conductive paste is applied to a part (for example, a side surface) of the surface of the prepared multilayer chip. Examples of the method of applying the conductive paste include a dip coating method, a dispenser supply method, printing methods such as screen printing, gravure printing, offset printing, and inkjet printing, and a spray coating method. When forming the external electrode of the MLCC, the dip coating method is more preferable.

[0068] 4. Firing Step In this step, the multilayer chip coated with the conductive paste is fired at a predetermined temperature. Thereby, the MLCC including the multilayer chip and the external electrode is formed. In this step, the conductive particles in the paste are sintered to form a porous fired body, and the glass powder is melted and filled in the voids of the fired body. At this time, the glass powder of the conductive paste disclosed herein has a configuration in which SiO2, Al2O3, B2O3, ZnO, and CaO are in a predetermined ratio and substantially does not contain BaO. Thereby, the glass component can be appropriately diffused throughout the external electrode, and an external electrode having sufficient adhesion performance can be formed. Note that the firing temperature (maximum firing temperature) in this step is preferably 650°C to 850°C, and more preferably about 670°C to 800°C.

[0069] As described above, specific embodiments of the technology disclosed herein include those described in the following sections.

[0070] [Item 1] Glass powder used in a conductive paste, The glass powder has the following composition in terms of mass ratio in terms of oxides: SiO2: 6 wt% - 18 wt%; B2O3: 18 wt% - 30 wt%; ZnO: 26 wt% - 47 wt%; Al2O3: 2 wt% - 17 wt%; CaO: 10 wt% - 25 wt%; and substantially does not contain BaO, Glass powder.

[0071] [Item 2] The glass powder according to Item 1, which substantially does not contain alkaline earth metal oxides other than CaO.

[0072] [Item 3] The glass powder according to Item 1 or 2, whose softening point is 500 °C or higher and 650 °C or lower.

[0073] [Item 4] The median diameter D 50 of the glass powder is 1 μm or more and 3 μm or less, and is the glass powder according to any one of Items 1 to 3.

[0074] [Item 5] The glass powder according to any one of Items 1 to 4, which contains 20 wt% or more of B2O3 in terms of mass ratio in terms of oxides.

[0075] [Item 6] The glass powder according to any one of Items 1 to 5, which contains 10 wt% or more of Al2O3 in terms of mass ratio in terms of oxides.

[0076] [Item 7] A conductive paste containing glass powder according to any one of Items 1 to 6, conductive particles, and a dispersion medium. Conductive paste.

[0077] [Item 8] The conductive paste according to Item 7, wherein the conductive particles are Cu particles.

[0078] [Item 9] The conductive paste according to Item 7 or 8, wherein when the total amount of the conductive paste is 100 wt%, the glass powder is contained in an amount of 4 wt% or more and 12 wt% or less.

[0079] [Item 10] A paste preparation step of preparing a conductive paste containing glass powder, conductive particles, and a dispersion medium; A laminated chip preparation step of preparing a laminated chip; A paste application step of applying the conductive paste prepared in the paste preparation step to the surface of the laminated chip prepared in the laminated chip preparation step; A firing step of firing the laminated chip coated with the conductive paste; A method for manufacturing a multilayer ceramic capacitor, comprising: The glass powder has the following composition in terms of mass ratio in terms of oxide: SiO2: 6 wt% to 18 wt%; B2O3: 18 wt% to 30 wt%; ZnO: 26 wt% to 47 wt%; Al2O3: 2 wt% to 17 wt%; CaO: 10 wt% to 25 wt%; And substantially does not contain BaO. A method for manufacturing a multilayer ceramic capacitor.

[0080] [Item 11] The laminated chip includes a dielectric layer mainly composed of a perovskite-type oxide. The method for manufacturing a multilayer ceramic capacitor according to Item 10.

[0081] [Item 12] As the perovskite-type oxide, including (CaSr)(TiZr)O3, The method for manufacturing a multilayer ceramic capacitor according to Item 11.

[0082] [Item 13] The method for manufacturing a multilayer ceramic capacitor according to any one of Items 10 to 12, wherein the firing step is performed at a firing temperature of 650 °C or higher and 850 °C or lower.

[0083] [Test Example] Next, test examples related to the technology disclosed herein will be described. Note that the test examples shown below are not intended to limit the technology disclosed herein.

[0084] [Preparation of Glass Powder] (1) Samples 1 to 12 Here, glass powder (median diameter D 50 : 1.5 μm) for use in the evaluation described later was prepared. The compositions of the glass powders related to Samples 1 to 12 are shown in Table 1.

[0085] [Evaluation of Glass Powder] 1 - 1. Evaluation of Adhesion Strength In this test, the adhesion strength of the glass powder related to each sample prepared above was evaluated.

[0086] (1) Preparation of Test Specimens First, plate-shaped Cu particles (median diameter D 50: A 4μm (particle size) was prepared. For the above Cu particles, the glass powder according to each example was mixed at an externally added ratio of 11 wt%. Then, by press molding, a button-shaped pellet with a diameter of φ15 mm and a thickness of 1.5 mm was produced. Next, a mixture of CSTZ powder and a binder (aqueous polyvinyl alcohol solution) was press-molded and fired at 1280 °C for 2 hours in an air atmosphere. Thereby, a flat substrate with dimensions of 26 mm × 26 mm × 1.3 mm (hereinafter referred to as CSTZ substrate) was prepared. Then, the pellet obtained above was placed on the CSTZ substrate prepared above, and a firing treatment was carried out at 730 °C for 30 minutes in a nitrogen atmosphere. Thereby, a test piece with the pellet fired on the substrate was obtained.

[0087] (2) Adhesion Strength Test Using a 4000 universal bond tester manufactured by Nordson DAGE, the strength (adhesion strength) when a load was applied to the pellet and the pellet peeled off was measured at room temperature. Specifically, among the test pieces prepared above, the substrate portion was fixed to the testing machine, and a shear force was applied to the pellet in a direction horizontal to the bonding surface by a shear tool. Then, the strength when the pellet peeled off from the substrate was defined as the adhesion strength (N). Such an evaluation was performed with N = 3 for each sample, and the arithmetic mean value (Ave. value) of the adhesion strength was calculated. Then, for each sample, those with an Ave. value exceeding 20 N were considered qualified. The results are shown in Table 1. Note that the higher the adhesion strength value, the better the adhesion performance of the pellet (i.e., the glass powder) (i.e., the more difficult it is to peel off).

[0088]

Table 1

[0089] As shown in Table 1, in Samples 5 to 7 in which BaO was contained in the glass powder, sufficient adhesion performance to the CSTZ substrate could not be obtained. On the other hand, in Samples 1 to 4, sufficient adhesive strength was confirmed. From this, it was found that when the glass powder used in the conductive paste was the glass powder of the composition of the present disclosure as in Samples 1 to 4, sufficient adhesive strength to the CSTZ substrate could be obtained. On the other hand, no adhesive strength was obtained for the pellets obtained with the conductive paste of Samples 8 to 12. This is presumably because the composition of the glass powder used in the conductive paste of Samples 8 to 12 was outside the scope of the present disclosure.

[0090] 2-1. Examination of Adhesive Strength Due to Difference in Firing Temperature In order to further evaluate the adhesion performance of the glass powder of the present disclosure, in this test, the adhesive strength with respect to different firing temperatures was examined for the evaluation pastes according to Sample 1 and Sample 2. Specifically, first, pellets according to Sample 1 and CSTZ substrates were prepared by the same method as described above. Then, except that the firing treatment temperature was set to 710 °C, a test piece having a fired film formed on the CSTZ substrate was obtained in the same manner as in 1-1. above. An adhesive strength test was performed on such a test piece in the same manner as the method described above. Also, for Sample 2, pellets and CSTZ substrates were prepared under the same conditions, and an adhesive strength test was performed under the same conditions as Sample 1. The results are shown in Table 2.

[0091]

Table 2

[0092] As shown in Table 2, for Sample 1, it was confirmed that good adhesive strength could be obtained even when the pellets were fired at 710 °C. Also, for Sample 2, good adhesive strength was obtained when fired at 710 °C in the same manner.

[0093] 2-2. Examination of Adhesive Strength on Barium Titanate Substrate (BT Substrate) In this test, the adhesion strength of the glass powders related to Sample 1 and Sample 2 to the BT substrate was examined. Specifically, first, pellets related to Sample 1 were prepared by the same method as above. Next, a mixture of barium titanate powder and a binder was press-molded and fired at 1300 °C for 2 hours in an air atmosphere. As a result, a flat barium titanate substrate (hereinafter referred to as BT substrate) with dimensions of 26 mm × 26 mm × 1.3 mm was prepared. Then, the pellets related to Sample 1 were placed on the above BT substrate, and a firing treatment was carried out for 30 minutes in a nitrogen atmosphere. Thereby, test pieces were obtained. In addition, in order to evaluate the adhesion strength for each firing temperature, test pieces obtained by performing the above firing treatment at 730 °C or 710 °C were prepared respectively. An adhesion strength test was performed on such test pieces in the same manner as the method described above. Also, for Sample 2, pellets and a BT substrate were prepared under the same conditions, and an adhesion strength test was performed under the same conditions as Sample 1. The results are shown in Table 3.

[0094]

Table 3

[0095] As shown in Table 3, it was confirmed that good adhesion strength was obtained for both Sample 1 and Sample 2 even when the adhesion strength test was performed using a BT substrate instead of the CSTZ substrate. From the viewpoint of the firing temperature, it was confirmed that good adhesion strength was obtained even when firing was performed at 710 °C with respect to the BT substrate.

[0096] 3. Scratch Evaluation Here, in order to further evaluate the properties of the glass powder of the present disclosure, the glass powders related to Sample 1, Samples 4 to 5, and Sample 12 were evaluated by a scratch test.

[0097] (1) Preparation of Conductive Paste for Evaluation First, a conductive paste for evaluation was prepared. Specifically, first, 74 wt% of conductive particles (median diameter D 50: 4-μm plate-shaped Cu particles), 8 wt% glass powder according to Samples 1, 4 to 5, and 12, 5 wt% binder (acrylic resin, molecular weight 150,000 to 200,000), 12.7 wt% dispersion medium (dihydroterpineol), and 0.3 wt% dispersant (carboxylic acid-based dispersant) were mixed to prepare a conductive paste. Thereby, the conductive pastes for evaluation according to Samples 1, 4 to 5, and 12 were obtained.

[0098] (2) Formation of the evaluation electrode First, a laminated chip (laminated ceramic capacitor body) in which a dielectric layer mainly composed of CSTZ of 0402 size and an internal electrode are laminated was prepared. The conductive paste for evaluation of Sample 1 was applied to the portion where the internal electrode was exposed on the end face of the laminated chip. Note that the dip coating method was used for applying the paste. Then, using a hot air dryer, drying treatment was performed at 120°C for 10 minutes. And firing treatment was performed on the formed dry film. Note that the firing time was 10 minutes, and the total treatment time including the temperature rising time (time from the start of firing to the end of firing) was set to 1 hour. The firing atmosphere was set to a nitrogen atmosphere. Note that in this evaluation, in order to examine the difference in the scratching strength of the external electrode depending on the firing temperature, for each sample, those in which the firing temperature of the dry film was changed to 700°C, 715°C, 730°C, and 750°C respectively were prepared as evaluation electrodes. In this way, an evaluation electrode in which the conductive paste for evaluation of Sample 1 was formed on the surface of the laminated chip as an external electrode was fabricated. Also, for Samples 4, 5, and 12, evaluation electrodes were formed under the same conditions.

[0099] (3) Scratch test With respect to the evaluation electrode obtained above, the scratch strength (scraping strength) of the external electrode was evaluated at room temperature. After the test, the state of the external electrode was observed with an optical microscope. Fig. 2 is a photograph of the evaluation electrode formed using Sample 1 after the scratch test. Fig. 3 is a photograph of the evaluation electrode formed using Sample 4 after the scratch test. Fig. 4 is a photograph of the evaluation electrode formed using Sample 5 after the scratch test. Fig. 5 is a photograph of the evaluation electrode formed using Sample 12 after the scratch test. In Figs. 2 to 5, the bright part in the upper half indicates the external electrode formed on the substrate, and the dark part indicates that the external electrode has peeled off (been damaged) from the substrate.

[0100] As shown in Figs. 4 and 5, significant peeling of the external electrode after the scratch test was observed in the external electrodes obtained by firing Sample 5 and Sample 12. On the other hand, as shown in Figs. 2 and 3, in the external electrodes of Sample 1 and Sample 4, suppression of peeling of the external electrode was confirmed compared to Sample 5 and Sample 12, regardless of the firing temperature. From this, it was also found that the external electrodes of Sample 1 and Sample 4 have good scraping strength with respect to the multilayer chip (multilayer ceramic capacitor element).

[0101] Although the technologies disclosed herein have been described in detail above, these are merely examples, and various modifications can be made to the present disclosure without departing from its gist.

Explanation of Reference Numerals

[0102] 1 Multilayer Ceramic Capacitor (MLCC) 10 Multilayer Chip 20 Dielectric Layer 30 Internal Electrode Layer 40 External Electrode

Claims

1. Glass powder used in a conductive paste, wherein the glass powder has the following composition in terms of mass ratio in terms of oxides: SiO ２ : 6 wt% to 18 wt%; B ２ O ３ : 18 wt% to 30 wt%; ZnO: 26 wt% to 47 wt%; Al ２ O ３ : 2 wt% to 17 wt%; CaO: 10 wt% to 25 wt%; and substantially does not contain BaO, glass powder.

2. The glass powder according to claim 1, wherein the glass powder substantially does not contain alkaline earth metal oxides other than CaO.

3. The glass powder according to claim 1, wherein the softening point of the glass powder is 500°C or higher and 650°C or lower.

4. The median diameter D of the glass powder ５０ is 1 μm or more and 3 μm or less, and the glass powder according to claim 1.

5. The glass powder contains B in a mass ratio in terms of oxide conversion of ２ O ３ of 20 wt% or more. The glass powder according to claim 1.

6. The glass powder contains 10 wt% or more of Al in terms of the mass ratio in terms of oxide conversion. ２ O ３ The glass powder according to claim 5.

7. A conductive paste comprising the glass powder according to any one of claims 1 to 3, conductive particles, and a dispersion medium. Conductive paste.

8. The conductive paste according to claim 7, wherein the conductive particles are Cu particles.

9. The conductive paste according to claim 7, wherein when the entire conductive paste is 100 wt%, the glass powder is contained in an amount of 4 wt% or more and 12 wt% or less.

10. A paste preparation step of preparing a conductive paste containing glass powder, conductive particles, and a dispersion medium; A laminated chip preparation step of preparing a laminated chip; A paste application step of applying the conductive paste prepared in the paste preparation step to the surface of the laminated chip prepared in the laminated chip preparation step; A firing step of firing the laminated chip coated with the conductive paste; A method for manufacturing a multilayer ceramic capacitor, comprising: wherein the glass powder has the following composition in terms of mass ratio in terms of oxides: SiO ２ : 6 wt% to 18 wt%; B ２ O ３ : 18 wt% to 30 wt%; ZnO: 26 wt% to 47 wt%; Al ２ O ３ : 2 wt% to 17 wt%; CaO: 10 wt% to 25 wt%; and substantially does not contain BaO, A method for manufacturing a multilayer ceramic capacitor.

11. The method for manufacturing a multilayer ceramic capacitor according to claim 10, wherein the laminated chip includes a dielectric layer mainly composed of a perovskite-type oxide. The method for manufacturing a multilayer ceramic capacitor according to claim 10.

12. As the perovskite-type oxide, (CaSr)(TiZr)O ３ including The method for manufacturing a multilayer ceramic capacitor according to claim 11.

13. The firing step is performed at a firing temperature of 650°C or higher and 850°C or lower. The method for manufacturing a multilayer ceramic capacitor according to claim 10 or 11.

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