Ceramic electronic components and methods for manufacturing the same

Abstract

To provide a large-capacity ceramic electronic component capable of suppressing delamination and a manufacturing method for the same.SOLUTION: A ceramic electronic component has a plurality of dielectric layers alternately stacked on top of each other and a plurality of internal electrode layers, and an auxiliary electrode protruding inside one of the plurality of dielectric layers from at least one surface of a pair of internal electrode layers facing each other across one of the plurality of dielectric layers of the plurality of internal electrode layers. The angle of the protruding direction of the auxiliary electrode with respect to the surface is greater than 0 degrees and less than or equal to 45 degrees.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This invention relates to ceramic electronic components and methods for manufacturing the same. Regarding. [Background technology]

[0002] Ceramic electronic components such as multilayer ceramic capacitors, in which internal electrode layers and dielectric layers are alternately stacked, are known. Regarding ceramic electronic components, for example, Patent Document 1 discloses that in order to suppress delamination (peeling) between layers of a multilayer electronic component, a columnar ceramic sintered body (hereinafter referred to as a columnar member) is provided to bond the ceramic layers together, and further, an uneven region is formed on the surface of the ceramic layer to increase the bonding force between layers through an anchoring effect. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2017-174945 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, since the column members penetrate the internal electrode layer in the thickness direction, the area of ​​the internal electrode layer decreases, making it difficult to increase the capacity of the laminated electronic component. Furthermore, if only the uneven regions of the ceramic layer are provided in the laminated electronic component, the thinner the ceramic layer, the lower the anchoring effect becomes, making it difficult to obtain sufficient interlayer bonding force, thus making it difficult to suppress delamination.

[0005] This invention has been made in view of the above problems, and aims to provide a high-capacity ceramic electronic component and a method for manufacturing the same that can suppress delamination. [Means for solving the problem]

[0006] The ceramic electronic component according to the present invention has a plurality of alternately stacked dielectric layers and a plurality of internal electrode layers, and an auxiliary electrode that protrudes into the interior of one of the plurality of dielectric layers from the surface of at least one of a pair of internal electrode layers that face each other across one of the plurality of dielectric layers, wherein the angle of the protrusion direction of the auxiliary electrode with respect to the surface is greater than 0 degrees and 45 degrees or less.

[0007] In the ceramic electronic component described above, the angle of the protrusion direction of the auxiliary electrode relative to the surface may be greater than 0 degrees and 30 degrees or less.

[0008] In the ceramic electronic component described above, the angle of the protrusion direction of the auxiliary electrode relative to the surface may be greater than 0 degrees and 20 degrees or less.

[0009] In the ceramic electronic component described above, the distance from the tip of the auxiliary electrode to the surface in the thickness direction of the dielectric layer may be half or less of the thickness of one of the plurality of dielectric layers.

[0010] In the ceramic electronic component described above, the auxiliary electrode may have a plate shape.

[0011] In the ceramic electronic component described above, the auxiliary electrode may have a plate shape with an aspect ratio of 1.5 to 15.

[0012] The ceramic electronic component described above may have a plate shape with an aspect ratio of 3.5 to 15.

[0013] The ceramic electronic component according to the present invention has a plurality of alternately stacked dielectric layers and a plurality of internal electrode layers, and an auxiliary electrode that protrudes into the interior of one of the plurality of dielectric layers from at least one surface of a pair of internal electrode layers that face each other across one of the plurality of dielectric layers. The auxiliary electrode has a substantially elliptical plate shape with a width that widens in a direction perpendicular to the direction in which the auxiliary electrode protrudes. In the thickness direction of the dielectric layer, the distance from the tip of the auxiliary electrode to the surface is 1 / 10 or more of the thickness of one of the plurality of dielectric layers. and less than the thickness of one of the plurality of dielectric layers. .

[0014] The ceramic electronic component according to the present invention has a plurality of dielectric layers and a plurality of internal electrode layers laminated alternately, and among the plurality of internal electrode layers, an auxiliary electrode protruding into one of the plurality of dielectric layers from at least one surface of a pair of internal electrode layers facing each other with one of the plurality of dielectric layers interposed therebetween. The auxiliary electrode The auxiliary electrode has a substantially elliptical plate shape with a width that widens in a direction perpendicular to the direction in which it protrudes, the auxiliary electrode of aspect ratio teeth, is 1.5 to 15 ru .

[0015] The method for manufacturing a ceramic electronic component according to the present invention includes a step of adding boron nitride having a hexagonal crystal structure to a ceramic raw material, a step of generating a dielectric green sheet from the ceramic raw material to which the boron nitride is added, a step of printing an internal electrode pattern on the surface of the dielectric green sheet with a metal conductive paste, a step of forming a laminate by laminating the dielectric green sheets on which the internal electrode pattern is printed, and a step of firing the laminate in a reducing atmosphere so that the boron nitride changes into voids and the metal conductive paste flows into the voids adjacent to the internal electrode pattern. Furthermore, in the process of firing the laminate, the firing temperature is increased at a rate of 1000°C / hour or more within the range of 600 to 900°C. is the method.

[0016] In the method for manufacturing the above ceramic electronic component, the particles of the boron nitride may have a plate shape with an aspect ratio of 1.5 to 15.

[0017] In the method for manufacturing the above ceramic electronic component, in the step of adding the boron nitride to the ceramic raw material, the concentration of the boron nitride with respect to the ceramic raw material may be 0.01 to 0.30 (wt%).

[0019] In the method for manufacturing the above ceramic electronic component, in the step of firing the laminate, the firing temperature may be raised at a rate of 300 (°C / hour) or less within a range of 1000 to 1200 (°C). [[Effect of the Invention]]

[0020] According to the present invention, the capacitance of ceramic electronic components can be increased and delamination can be suppressed. [Brief explanation of the drawing]

[0021] [Figure 1] This is a perspective view showing an example of a multilayer ceramic capacitor. [Figure 2] This is a cross-sectional view of a multilayer ceramic capacitor along line AA in Figure 1. [Figure 3] This is a partial cross-sectional view of a multilayer chip showing an example of an auxiliary electrode. [Figure 4] This is a cross-sectional view showing the angle of the protruding direction of the auxiliary electrode. [Figure 5] This is a partial cross-sectional view of a multilayer chip showing an example of another auxiliary electrode. [Figure 6] This figure shows an example of the manufacturing process for multilayer ceramic capacitors. [Figure 7] This figure shows a photograph of hBN particles taken with a scanning electron microscope. [Figure 8] This is a cross-sectional view showing an example of the internal electrode printing process in a side view. [Figure 9] This is a cross-sectional view showing an example of the lamination process in a side view. [Figure 10] This is a partial cross-sectional view of the laminate before the start of the firing process. [Figure 11] This is a partial cross-sectional view of the laminate during the firing process. [Figure 12] This is a partial cross-sectional view of the laminate after the firing process. [Modes for carrying out the invention]

[0022] [Embodiment] (Configuration of multilayer ceramic capacitors) Figure 1 is a perspective view showing an example of a multilayer ceramic capacitor 1. The multilayer ceramic capacitor 1 comprises a stacked chip 2 with a substantially rectangular parallelepiped shape and external electrodes 3a and 3b provided on two opposing end faces of either the stacked chip 2. The multilayer ceramic capacitor 1 is an example of a ceramic electronic component. In the following description, the end faces of the stacked chip 2 in the stacking direction will be referred to as the top and bottom faces, and of the other four end faces, the end faces other than the two end faces on which the external electrodes 3a and 3b are provided will be referred to as the side faces.

[0023] The external electrodes 3a and 3b extend to the top, bottom, and both sides of the stacked chip 2. However, the external electrodes 3a and 3b are spaced apart from each other. The stacked chip 2 has the layer configuration described below.

[0024] Figure 2 is a cross-sectional view of the multilayer ceramic capacitor 1 along line AA in Figure 1. Note that the scale of the multilayer ceramic capacitor 1 shown in Figure 2 is different from that of the multilayer ceramic capacitor 1 in Figure 1 for convenience. The multilayer chip 2 has a structure in which dielectric layers 23 containing a ceramic material that functions as a dielectric and internal electrode layers 22a and 22b containing a base metal material are alternately stacked.

[0025] The edge of the internal electrode layer 22a is exposed to the end face of the multilayer chip 2 on which the external electrode 3a is provided and is electrically connected to the external electrode 3a. The edge of the internal electrode layer 22b is exposed to the end face of the multilayer chip 2 on which the external electrode 3b is provided and is electrically connected to the external electrode 3b. The internal electrode layers 22a and 22b are stacked alternately in the stacking direction of the multilayer ceramic capacitor 1, with the dielectric layer 23 in between.

[0026] The upper and lower surfaces of the stacked chip 2 are formed by cover layers 20 and 21, respectively. The upper cover layer 20 is adjacent to the uppermost internal electrode layer 22b in the stacking direction, and the lower cover layer 21 is adjacent to the lowermost internal electrode layer 22a in the stacking direction. The cover layers 20 and 21 are mainly composed of ceramic material. For example, the main components of the ceramic material are the same as those of the dielectric layer 23.

[0027] The external electrodes 3a and 3b are mainly composed of Ni, Cu, etc. A plating layer mainly composed of a metal such as Cu, Ni, Al, Zn, Sn or an alloy of two or more of these may be provided on the surfaces of the external electrodes 3a and 3b.

[0028] The dielectric layer 23 mainly consists of, for example, a ceramic material having a perovskite structure represented by the general formula ABO3. Note that the perovskite structure contains ABO deviated from the stoichiometric composition. 3-α For example, as the ceramic material, at least one of BaTiO3 (barium titanate), CaZrO3 (calcium zirconate), CaTiO3 (calcium titanate), SrTiO3 (strontium titanate), MgTiO3 (magnesium titanate), Ba 1-x-y Ca x Sr y Ti 1-z Zr z O3 (0≦x≦1, 0≦y≦1, 0≦z≦1), etc. can be selected and used. Ba 1-x-y Ca x Sr y Ti 1-z Zr z O3 includes barium strontium titanate, barium calcium titanate, barium zirconate, barium zirconium titanate, calcium zirconium titanate, and barium calcium zirconium titanate, etc.

[0029] The internal electrode layers 22a and 22b are mainly composed of base metals such as Ni (nickel), Cu (copper), Sn (tin), etc. As additives to the internal electrode layers 22a and 22b, noble metals such as Pt (platinum), Pd (palladium), Ag (silver), Au (gold), or Sn (tin) may be used. Also, the internal electrode layers 22a and 22b may use alloys containing these elements.

[0030] In addition, at least one of the pair of internal electrode layers 22a and 22b facing each other with the dielectric layer 23 interposed therebetween has an auxiliary electrode protruding into the dielectric layer 23. Hereinafter, the auxiliary electrode in the region indicated by the symbol P will be taken as an example for explanation.

[0031] Figure 3 is a partial cross-sectional view of the multilayer chip 2 showing an example of the auxiliary electrode 221b. Figure 3 shows a side view and a front view cross-section from the external electrode 3b side of the region indicated by the symbol P in Figure 2.

[0032] The auxiliary electrode 221b protrudes into the dielectric layer 23 from the surface 220b of one of the pair of internal electrode layers 22a and 22b that face each other across the dielectric layer 23. The auxiliary electrode 221b is formed integrally with the internal electrode layer 22b. Therefore, the main components of the auxiliary electrode 221b and the internal electrode layer 22b are the same.

[0033] The angle θb of the protrusion direction of the auxiliary electrode 221b relative to the surface 220b of the internal electrode layer 22b is greater than 0 degrees and less than or equal to 45 degrees. As will be described later, this angle θb depends on the direction of the hBN particles when boron nitride (hBN), which has a hexagonal crystal structure, is added to the ceramic raw material of the dielectric layer 23 during the manufacturing of the multilayer ceramic capacitor 1.

[0034] For example, when observing the stacked cross-section of the stacked chip 2 with a scanning electron microscope (SEM), unlike the schematic diagram shown in Figure 3, the surfaces of the internal electrode layers 22a and 22b are not flat but have irregularities, and the auxiliary electrode 221b is not straight but, for example, jagged. From this perspective, the definition of the angle θb in the protrusion direction is described in detail below.

[0035] Figure 4 is a cross-sectional view showing the angle θb in the protruding direction of the auxiliary electrode 221b. The surfaces 220a and 220b of the internal electrode layers 22a and 22b may be flat, but they may also be uneven and have irregularities. In addition, the auxiliary electrode 221b may be formed in a straight line, but it may also be distorted in a jagged manner.

[0036] The symbol Mw represents an enlarged view of the base region Sw of the auxiliary electrode 221b on surface 220b. Points P1c and P2c are the two ends of the base of the auxiliary electrode 221b on surface 220b. Point Pc is the midpoint of the line segment Lc connecting the two ends, P1c and P2c.

[0037] Five points Pk are set on the surface 220b (boundary with the dielectric layer 23) at a constant interval k (e.g., 5 μm) in the left-right direction on the plane of Figure 4, perpendicular to the stacking direction of the stacked chip 2 from point Pc. The straight line Ls is obtained by linearly approximating the 10 points Pk. The straight line Lh is obtained by connecting point Pc and the tip 221bp of the auxiliary electrode 221b. The angle between these two straight lines Ls and Lh is defined as the angle θb in the protruding direction of the auxiliary electrode 221b.

[0038] The angle θb in the protruding direction of the auxiliary electrode 221b is greater than 0 degrees and 45 degrees or less. Thus, the auxiliary electrode 221b protrudes into the dielectric layer 23 at a shallow angle of 45 degrees or less relative to the surface 220b of the internal electrode layer 22b. Therefore, when stress is applied to the internal electrode layer 22b and the dielectric layer 23 in the stacking direction, the anchoring effect of the auxiliary electrode 221b suppresses the separation of the internal electrode layer 22b and its adjacent dielectric layer 23.

[0039] In contrast, as in Patent Document 1, for example, when an uneven region is provided in the dielectric layer 23, the thinner the dielectric layer 23 becomes, the lower the anchoring effect becomes, making it difficult to obtain sufficient bonding force between the dielectric layer 23 and the internal electrode layer 22b, thus making it difficult to suppress delamination. The auxiliary electrode 221b protrudes into the dielectric layer 23 at a shallow angle of 45 degrees or less relative to the surface 220b of the internal electrode layer 22b, so a sufficient anchoring effect can be obtained even when the dielectric layer 23 is thin.

[0040] Furthermore, by setting the angle θb in the protruding direction to greater than 0 degrees and 45 degrees or less, an anchoring effect to the dielectric layer 23 can be obtained while ensuring insulation between the internal electrode layer 22b and the other internal electrode layer 22a facing it. Preferably, setting the angle θb in the protruding direction to 0 to 30 degrees can improve insulation with the opposing internal electrode. Even more preferably, setting the angle θb in the protruding direction to 0 to 20 degrees can further improve insulation with the opposing internal electrode.

[0041] Furthermore, the auxiliary electrode 221b allows for an increase in the area of ​​the internal electrode in contact with the dielectric layer 23 compared to when the auxiliary electrode 221b is not provided. This not only further increases the bonding force between the internal electrode layer 22b and the dielectric layer 23, but also increases the capacitance of the multilayer ceramic capacitor 1.

[0042] In the thickness direction of the dielectric layer 23, the distance Hb from the tip 221bp of the auxiliary electrode 221b to the surface 220b of the internal electrode layer 22b is preferably half or less of the thickness D of the dielectric layer 23. This ensures that the distance between the other internal electrode layer 22a facing the internal electrode layer 22b and the tip 221bp of the auxiliary electrode 221b is half or more of the thickness D of the dielectric layer 23, thereby ensuring sufficient insulation between the auxiliary electrode 221b and the internal electrode layer 22a. More preferably, the distance Hb may be set to less than one-third or one-quarter of the thickness D of the dielectric layer 23 to further enhance insulation.

[0043] Furthermore, in the thickness direction of the dielectric layer 23, the distance Hb from the tip 221bp of the auxiliary electrode 221b to the surface 220b of the internal electrode layer 22b is at least one-tenth of the thickness D of the dielectric layer 23. Therefore, even when the dielectric layer 23 is thin, the auxiliary electrode 221b can penetrate to a sufficient depth into the dielectric layer 23, thereby sufficiently increasing the bonding force between the internal electrode layer 22b and the dielectric layer 23. Consequently, when stress is applied to the internal electrode layer 22b and the dielectric layer 23 in the stacking direction, the anchoring effect of the auxiliary electrode 221b suppresses the separation of the internal electrode layer 22b and its adjacent dielectric layer 23.

[0044] Furthermore, the auxiliary electrode 221b has a plate shape. This plate shape depends on the shape of the hBN particles, as will be described later. The aspect ratio of the auxiliary electrode 221b is, for example, 1.5 to 15. By setting the aspect ratio in this way, the auxiliary electrode 221b can penetrate a sufficient area into the dielectric layer 23 even when the dielectric layer 23 is thin, thereby sufficiently increasing the bonding force between the internal electrode layer 22b and the dielectric layer 23. Therefore, when stress is applied to the internal electrode layer 22b and the dielectric layer 23 in the stacking direction, the anchoring effect of the auxiliary electrode 221b suppresses the separation of the internal electrode layer 22b and its adjacent dielectric layer 23.

[0045] Furthermore, it is preferable that the auxiliary electrode 221b has a substantially elliptical plate shape. With this shape, in the thickness direction of the dielectric layer 23, the width of the auxiliary electrode 221b extends from the surface 220b of the internal electrode layer 22b to a position about half the distance Hb mentioned above. As a result, the bonding force between the internal electrode layer 22b and the dielectric layer 23 is higher than when the auxiliary electrode 221b has, for example, a rectangular plate shape.

[0046] (Other examples of multilayer ceramic capacitors) In this example, the auxiliary electrode 221b is provided only in one internal electrode layer 22b, but it may also be provided in the other internal electrode layer 22a, as described below.

[0047] Figure 5 is a partial cross-sectional view of the multilayer chip 2 showing examples of other auxiliary electrodes 221a and 221b. In Figure 5, components common to Figure 3 are denoted by the same reference numerals, and their descriptions are omitted.

[0048] In this example, in addition to the auxiliary electrode 221b of one internal electrode layer 22b, an auxiliary electrode 221a is also provided in the other internal electrode layer 22a. The auxiliary electrode 221a protrudes from the surface 220a of the internal electrode layer 22a into the interior of the dielectric layer 23. The auxiliary electrode 221a is formed integrally with the internal electrode layer 22a. Therefore, the main components of the auxiliary electrode 221a and the internal electrode layer 22a are the same.

[0049] Furthermore, the angle θa of the protruding auxiliary electrode 221a with respect to the surface 220a of the internal electrode layer 22a is greater than 0 degrees and 45 degrees or less, similar to the angle θb of the other auxiliary electrode 221b. Therefore, when stress is applied to the internal electrode layer 22a and the dielectric layer 23 in the vertical direction, the anchoring effect of the auxiliary electrode 221a suppresses the separation of the internal electrode layer 22a and its adjacent dielectric layer 23.

[0050] Furthermore, the auxiliary electrode 221a allows for an increase in the area of ​​the internal electrode in contact with the dielectric layer 23 compared to when the auxiliary electrode 221a is not provided. This not only further increases the bonding force between the internal electrode layer 22a and the dielectric layer 23, but also increases the capacitance of the multilayer ceramic capacitor 1.

[0051] In the thickness direction of the dielectric layer 23, the distance Ha from the tip 221ap of the auxiliary electrode 221a to the surface 220a of the internal electrode layer 22a is preferably half or less of the thickness D of the dielectric layer 23. This ensures that the distance between the other internal electrode layer 22b facing the internal electrode layer 22a and the tip 221ap of the auxiliary electrode 221a is half or more of the thickness D of the dielectric layer 23, thereby ensuring sufficient insulation between the auxiliary electrode 221a and the internal electrode layer 22b. More preferably, the distance Ha may be set to one-third or one-quarter or less of the thickness D of the dielectric layer 23 to further enhance insulation.

[0052] Furthermore, in the thickness direction of the dielectric layer 23, the distance Ha from the tip 221ap of the auxiliary electrode 221a to the surface 220a of the internal electrode layer 22a is at least one-tenth of the thickness D of the dielectric layer 23. Therefore, even when the dielectric layer 23 is thin, the auxiliary electrode 221a can penetrate to a sufficient depth into the dielectric layer 23, thereby sufficiently increasing the bonding force between the internal electrode layer 22a and the dielectric layer 23. Consequently, when stress is applied to the internal electrode layer 22a and the dielectric layer 23 in the stacking direction, the anchoring effect of the auxiliary electrode 221a suppresses the separation of the internal electrode layer 22b and its adjacent dielectric layer 23.

[0053] Furthermore, the auxiliary electrode 221a has a plate shape. This plate shape depends on the shape of the hBN particles, as will be described later. The aspect ratio of the auxiliary electrode 221a is, for example, 1.5 to 15. By setting the aspect ratio in this way, the auxiliary electrode 221a can penetrate a sufficient area into the dielectric layer 23 even when the dielectric layer 23 is thin, thereby sufficiently increasing the bonding force between the internal electrode layer 22a and the dielectric layer 23. Therefore, when stress is applied to the internal electrode layer 22a and the dielectric layer 23 in the stacking direction, the anchoring effect of the auxiliary electrode 221a suppresses the separation of the internal electrode layer 22b and its adjacent dielectric layer 23.

[0054] Furthermore, it is preferable that the auxiliary electrode 221a has a substantially elliptical plate shape. With this shape, in the thickness direction of the dielectric layer 23, the width of the auxiliary electrode 221a extends from the surface 220a of the internal electrode layer 22a to a position about half the distance Hb mentioned above. As a result, the bonding force between the internal electrode layer 22a and the dielectric layer 23 is higher than when the auxiliary electrode 221a has, for example, a rectangular plate shape.

[0055] Furthermore, the aspect ratio of the auxiliary electrode 221a is preferably, for example, 3.5 to 15. By setting the aspect ratio in this way, the coupling force between the internal electrode layer 22a and the dielectric layer 23 can be further increased, and the capacitance value can be further increased.

[0056] (Manufacturing method for multilayer ceramic capacitors) Next, the manufacturing method of the multilayer ceramic capacitor 1 will be described. The auxiliary electrodes 221a and 221b mentioned above are produced by hBN particles added to the ceramic material, which is the raw material for the dielectric layer 23.

[0057] Figure 6 shows an example of the manufacturing process for a multilayer ceramic capacitor 1. The manufacturing process for the multilayer ceramic capacitor 1 is an example of a method for manufacturing ceramic electronic components.

[0058] (Process for producing raw material powder) First, the raw material powder preparation process St1 is carried out. In the raw material powder preparation process St1, ceramic powder (ceramic raw material) is prepared as a dielectric material for forming the dielectric layer 11. The A-site and B-site elements contained in the dielectric layer 11 are usually contained in the dielectric layer 11 in the form of a sintered body of ABO3 particles. For example, BaTiO3 is a tetragonal compound having a perovskite structure and exhibits a high dielectric constant. This BaTiO3 can generally be obtained by synthesizing barium titanate by reacting a titanium raw material such as titanium dioxide with a barium raw material such as barium carbonate. Various methods have been conventionally known for synthesizing the main component ceramic of the dielectric layer 11, such as the solid-phase method, the sol-gel method, and the hydrothermal method. In this embodiment, any of these can be used.

[0059] (Additive blending process) Next, the additive compounding process St2 is carried out. In the additive compounding process St2, various additive compounds are added to the ceramic powder obtained in the raw material powder preparation process St1. Examples of additive compounds include elements that improve reliability, such as insulation, and sintering aids that improve sinterability in the sintering process, as will be described later. Examples of this type of additive compound include oxides of Mg (magnesium), Mn (manganese), V (vanadium), Cr (chromium), rare earth elements (Y (yttrium), Sm (samarium), Eu (europium), Gd (gadolinium), Tb (terbium), Dy (dysprosium), Ho (holomium), Er (erbium), Tm (thulium), and Yb (ytterbium)), as well as oxides or glass of Ni, Li (lithium), B (boron), Na (sodium), K (potassium), and Si (silicon) as sintering aids.

[0060] Furthermore, hBN is added to the ceramic powder as an additive compound for forming auxiliary electrodes 221a and 221b. The addition of hBN is only necessary for the ceramic powder of the dielectric green sheet to which the internal electrode pattern described later will be printed. The hBN is added so that the hBN particles are randomly distributed within the dielectric green sheet, as described later.

[0061] Figure 7 shows a photograph of hBN particles taken with a scanning electron microscope (SEM). As can be seen from Figure 7, hBN particles have a crystalline structure that easily cleaves in one direction, and therefore contain many plate-shaped particles. The particle size of the hBN particles is preferably, for example, 0.3 to 10 (μm), and more preferably 0.6 to 5.0 (μm).

[0062] Furthermore, when adding hBN, the concentration of hBN relative to the main component of the ceramic powder is preferably 0.01 to 0.30 (wt%), and more preferably 0.05 to 0.10 (wt%). By setting the hBN concentration in this way, in the cross-sectional view shown in Figures 3 and 5, 0.05 to 3.0 auxiliary electrodes 221a, 221b are obtained for each internal electrode layer 22a, 22b, and sufficient bonding force is obtained between the internal electrode layers 22a, 22b and the dielectric layer 23.

[0063] Referring again to Figure 6, in the additive compounding step St2, for example, a ceramic material is prepared by wet mixing a compound containing the additive compound with ceramic powder, drying, and grinding. For example, the ceramic material obtained as described above may be ground to adjust the particle size as needed, or the particle size may be adjusted by combining it with a classification process. Through the above steps, a dielectric material for forming the dielectric layer 23 is obtained. For example, in one container, the amount of dielectric material used for multiple multilayer ceramic capacitors 1 is produced in the same process.

[0064] (Green sheet forming process) Next, the green sheet forming process St3 is performed. The green sheet forming process St3 is an example of a process for producing a dielectric green sheet from a dielectric material to which hBN has been added.

[0065] For example, the dielectric material obtained in additive blending step St2 is wet-mixed with a binder such as polyvinyl butyral (PVB) resin, an organic solvent such as ethanol or toluene, and a plasticizer. Using the resulting slurry, a dielectric green sheet with a thickness of, for example, 4 μm or more is coated onto a substrate using a die coater or doctor blade method and dried. The substrate is, for example, a PET (polyethylene terephthalate) film.

[0066] (Internal electrode printing process) Next, the internal electrode printing process St4 is performed. The internal electrode printing process St4 is an example of a process in which an internal electrode pattern is printed on the surface of a dielectric green sheet using a metal conductive paste.

[0067] Figure 8 is a cross-sectional view showing an example of the internal electrode printing process St4 in a side view. As shown in Figure 5, a metal conductive paste for forming internal electrodes, containing an organic binder, is printed onto a dielectric green sheet 52 on a substrate 51 by screen printing, gravure printing, or the like, thereby forming multiple internal electrode patterns 53 spaced apart from each other.

[0068] Ceramic particles are added to the metal conductive paste as a co-material. The main component of the ceramic particles is not particularly limited, but it is preferable that it be the same as the main component ceramic of the dielectric layer 11. For example, BaTiO3 with an average particle diameter of 50 nm or less may be uniformly dispersed. In the example in Figure 8, four layers of internal electrode patterns 53 are deposited on the dielectric green sheet 52 at predetermined intervals. The dielectric green sheet 52 on which the internal electrode patterns 53 are deposited becomes the lamination unit in the following lamination process St5. The dielectric green sheet 52 on which the internal electrode patterns 53 are printed is punched out to a predetermined size.

[0069] (Lamination process) Next, the lamination process St5 is performed. Lamination process St5 is an example of a process in which a laminate is formed by stacking dielectric green sheets 52 on which an internal electrode pattern 53 is printed.

[0070] Figure 9 is a cross-sectional view showing an example of the lamination process St5 in a side view. After peeling the dielectric green sheet 52 from the substrate 51, the internal electrode layers 22a, 22b and the dielectric layer 23 are alternately laminated, and each end of the internal electrode layers 22a, 22b is alternately exposed on both ends in the longitudinal direction of the dielectric layer 11 and alternately led out to the external electrodes 3a, 3b. For example, 10 layers are laminated, with the above-mentioned lamination unit considered as one layer. Cover sheets for forming cover layers 20, 21 are pressed onto the top and bottom of the laminate 5 obtained by this lamination, and cut to a predetermined chip size (for example, 3.2 mm × 1.6 mm) along the line indicated by the symbol W.

[0071] (Firing process) Referring again to Figure 6, the firing process St6 is performed after the lamination process St5. The firing process St6 is an example of a process in which the laminate 5 is fired in a reducing atmosphere so that the hBN changes into pores and the metal conductive paste flows into the pores adjacent to the internal electrode pattern 53.

[0072] Figure 10 is a partial cross-sectional view of the laminate 5 before the start of the firing process St6. Specifically, Figure 10 is an enlarged view of the region indicated by the symbol Q in Figure 9. The symbols La to Ld indicate the boundaries of the internal electrode patterns 53a, 53b (53) and the dielectric green sheet 52.

[0073] The internal electrode patterns 53a and 53b include, for example, nickel (Ni) particles 60. The dielectric green sheet 52 also includes, for example, barium titanate (BaTiO3) particles 61, hBN particles 62a and 62b, and other additive particles. The hBN particles 62a and 62b have a plate shape similar to the auxiliary electrodes 221a and 221b described above.

[0074] The central axis Xa of the hBN particle 62a is inclined at an angle θ with respect to the interface (symbol Lb) between the internal electrode pattern 53b and the dielectric green sheet 52. One end of the hBN particle 62a is in contact with the internal electrode pattern 53b, but the other end of the hBN particle 62a is located near the center in the thickness direction of the dielectric green sheet 52 and is not in contact with either internal electrode pattern 53a or 53b. The angle θ is greater than 0 degrees and less than or equal to 45 degrees, similar to the angles θa and θb of the auxiliary electrodes 221a and 221b described above.

[0075] The central axis Xb of the hBN particle 62b is parallel (angle 0 degrees) to the interface (symbol Lb) between the internal electrode pattern 53b and the dielectric green sheet 52. Both ends of the hBN particle 62b are located near the center in the thickness direction of the dielectric green sheet 52 and are not in contact with either of the internal electrode patterns 53a or 53b.

[0076] In the firing process St6, when the firing temperature reaches approximately 800°C, the hBN particles 62a and 62b are oxidized, generating boron oxide (B2O3) and nitrogen (N2). The nitrogen is released to the outside, but the boron oxide remains in the region where the hBN particles 62a and 62b were present.

[0077] Figure 11 is a partial cross-sectional view of the laminate 5 during the firing process St6. In Figure 11, components common to Figure 10 are denoted by the same reference numerals, and their explanations are omitted. When the firing temperature reaches approximately 900°C during the firing process St6, the boron oxide chemically reacts with the surrounding barium titanate particles 61. As a result, the regions where the hBN particles 62a and 62b were present become voids (pores) 63a and 63b.

[0078] When the firing temperature exceeds 1000°C, the nickel particles 60 of the internal electrode pattern 53b sinter and shrink first, followed by the barium titanate particles 61 of the dielectric green sheet 52 sinter and shrink. The nickel particles 60 flow due to the high temperature and flow from the internal electrode pattern 53b (metal conductive paste) into the void 63a.

[0079] Figure 12 is a partial cross-sectional view of the laminate 5 after the firing process St6. In Figure 12, components common to Figure 11 are denoted by the same reference numerals, and their explanations are omitted. The internal electrode patterns 53a and 53b become the internal electrode layers 22a and 22b, respectively, and the nickel particles 60 that flowed into the void 63b become the auxiliary electrode 221b.

[0080] Furthermore, the dielectric green sheet 52 becomes the dielectric layer 23. The other void 63b remains as it is in the dielectric layer 23.

[0081] (Re-oxidation process) Referring again to Figure 6, after the firing process St6, the re-oxidation process St7 is performed. In the re-oxidation process St7, the laminate 5 is re-oxidized in an N2 gas atmosphere at 600-1000°C.

[0082] (External electrode formation process) Next, the external electrode formation process St8 is performed. In the external electrode formation process St8, a metal paste containing metal powder, glass frit, binder, and solvent is applied to both end faces of the laminated chip 2 and dried. After that, the metal paste is baked. This forms the external electrodes 3a and 3b. The binder and solvent evaporate during the baking process.

[0083] (Plating process) Next, the plating process St9 is performed. In the plating process St9, metal coatings such as Cu, Ni, and Sn are applied to the external electrodes 3a and 3b by plating. Through these processes, the multilayer ceramic capacitor 1 described above is completed.

[0084] In the manufacturing process of the multilayer ceramic capacitor 1, it is preferable that the hBN particles have a plate shape with an aspect ratio of 1.5 to 15. This allows for the aspect ratio of the auxiliary electrode 221b to be obtained as described above.

[0085] Furthermore, in the firing process St6, when the firing temperature is in the range of 600 to 900 (°C), it is preferable to raise the firing temperature at a rate of 1000 (°C / hour) or higher. In this firing temperature range, as described above, the hBN particles 62a and 62b are converted to boron oxide, which acts as a sintering aid for the barium titanate particles 61. Therefore, if firing is performed at a high sintering temperature for a long time, the sintering of the barium titanate particles 61 is accelerated, which may deform the voids 63a into which the nickel particles 60 flow, and prevent the formation of auxiliary electrodes 221b with an appropriate shape.

[0086] Therefore, by controlling the temperature of the firing furnace to rapidly raise the firing temperature at a rate of 1000°C / hour or higher, the shape of the void 63a is maintained while the nickel particles 60 are quickly flowed into the void 63a. This allows for the formation of the auxiliary electrode 221b with high precision. It is preferable that the particle size of the nickel particles 60 be as small as possible so that they flow easily into the void 63b.

[0087] Furthermore, in firing process St6, when the firing temperature is within the range of 1000-1200°C, the firing temperature is set to 300°C / hour. below It is preferable to raise the temperature at this rate. By controlling the temperature of the firing furnace so that the firing temperature increases slowly in this way, it becomes possible to pour a sufficient amount of nickel particles 60 into the void 63b.

[0088] Furthermore, in order to suppress the conversion of hBN particles 62a and 62b to boron oxide at low firing temperatures, firing process St6 is carried out in a reducing atmosphere in the firing furnace. For this reason, the oxygen partial pressure in the firing furnace is set, for example, to 10 at 1000 degrees. -14 ~10 -13 (atm) is approximately, and at 1200 degrees, 10 -11 ~10 -10 (Atm)

[0089] In this example, barium titanate is given as the main component of the dielectric layer 23, but it is not limited to this, and other dielectric materials may be used as the main component. Similarly, nickel is given as the main component of the internal electrode layers 22a and 22b, but it is not limited to this, and other conductive materials such as copper may be used as the main component. [Examples]

[0090] (Comparison of capacitance of multilayer ceramic capacitors) Next, we will describe the comparison between the capacitance of the multilayer ceramic capacitor 1 in this embodiment and the capacitance of the multilayer ceramic capacitor 1 without auxiliary electrodes 221a and 221b (hereinafter referred to as the comparative example). The multilayer ceramic capacitor 1 in this embodiment is provided with only one auxiliary electrode 221b.

[0091] [Table 1]

[0092] For this comparison, 50 units each of the multilayer ceramic capacitor 1 for the examples and comparative examples were manufactured. The average values ​​of various parameters for each multilayer ceramic capacitor 1 for the examples and comparative examples are shown in Table 1 above. For each multilayer ceramic capacitor 1 for the examples and comparative examples, the surface area was set to 420 μm². 2 The thickness of the internal electrode layers 22a and 22b was set to 2 μm, and the thickness D of the dielectric layer 23 was set to 10 μm. In addition, for the multilayer ceramic capacitor 1 of the example, the angles θa and θb of the auxiliary electrodes 221a and 221b were set to 20.7 degrees, and the distances Ha and Hb from the tips 221ap and 221bp of the auxiliary electrodes 221a and 221b to the surfaces 220a and 220b of the internal electrode layers 22a and 22b were set to one-third of the thickness D of the dielectric layer 23.

[0093] In the manufacturing of the multilayer ceramic capacitor 1 of the example, the following steps were performed.

[0094] In the raw material powder preparation step St1 described above, ceramic powder containing BaTiO3 was prepared. The dielectric constant of BaTiO3 was 3000. In the additive blending step St2 described above, hBN was added to the ceramic powder as an additive compound to form auxiliary electrodes 221a and 221b. The particle size of the hBN particles at this time was 3-4 (μm). The concentration of hBN relative to the ceramic powder was 0.1 (wt%).

[0095] In the green sheet molding process St3 described above, a dielectric green sheet was produced from a dielectric material to which hBN was added. In the internal electrode printing process St4, an internal electrode pattern was printed on the surface of the dielectric green sheet using Ni as a metallic conductive paste. In the lamination process St5 described above, a laminate was formed by laminating dielectric green sheets with printed internal electrode patterns.

[0096] Furthermore, in the firing process St6 described above, the firing temperature was raised to 800°C at 1000°C / hour, and then to 1180°C at 300°C / hour. After that, the re-oxidation process St7 described above was performed. Next, in the external electrode formation process St8 described above, external electrodes 3a and 3b were formed on the laminate, and in the plating process St9 described above, plating was performed on the external electrodes 3a and 3b. On the other hand, in the manufacturing of the comparative example multilayer ceramic capacitor 1, hBN particles were not added in the additive compounding step St2 described above, but the other steps were the same as those in the example.

[0097] [Table 2]

[0098] The capacitance of the multilayer ceramic capacitor 1 manufactured in this manner was measured by applying a voltage of 5 (V) between the external electrodes 3a and 3b. The measurement results are shown in Table 2 above. The average capacitance of the multilayer ceramic capacitor 1 of the example was calculated to be 88.1 (nF), and the average capacitance of the multilayer ceramic capacitor 1 of the comparative example was calculated to be 79.7 (nF). Therefore, it is understood that the multilayer ceramic capacitor 1 of the example has a larger capacitance than the comparative example due to the auxiliary electrode 221b.

[0099] This is thought to be due to the following reasons. In the manufacturing of the multilayer ceramic capacitor 1 of the example, as described above, among the hBN particles added in the additive blending step St2, hBN particles located at an angle greater than 0 degrees and 45 degrees or less with respect to the surface 220a of the internal electrode layer 22b became pores in the firing step St6, and further, the metal conductive paste of the internal electrode flowed into these pores, forming the auxiliary electrode 221b. On the other hand, in the manufacturing of the multilayer ceramic capacitor 1 of the comparative example, no hBN particles were added, so the auxiliary electrode 221b was not formed. For this reason, the capacitance of the multilayer ceramic capacitor 1 of the example was larger than that of the multilayer ceramic capacitor 1 of the comparative example by the surface integral of the auxiliary electrode 221b.

[0100] Although embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims. [Explanation of symbols]

[0101] 1. Multilayer ceramic capacitor 2 stacked chips 3a,3b External electrode 20,21 Cover layer 22a,22b Internal electrode layer 23 Dielectric layer 52 Dielectric Green Sheet 53a, 53b Internal electrode patterns 62a,62b hBN particles 221a, 221b auxiliary electrodes

Claims

1. Multiple dielectric layers and multiple internal electrode layers stacked alternately, Among the plurality of internal electrode layers, an auxiliary electrode protrudes from at least one surface of a pair of internal electrode layers facing each other across one of the plurality of dielectric layers into the interior of one of the plurality of dielectric layers, A ceramic electronic component characterized in that the angle of the protrusion direction of the auxiliary electrode relative to the surface is greater than 0 degrees and 45 degrees or less.

2. The ceramic electronic component according to claim 1, characterized in that the angle of the protrusion direction of the auxiliary electrode with respect to the surface is greater than 0 degrees and 30 degrees or less.

3. The ceramic electronic component according to claim 1, characterized in that the angle of the protrusion direction of the auxiliary electrode with respect to the surface is greater than 0 degrees and 20 degrees or less.

4. The ceramic electronic component according to any one of claims 1 to 3, characterized in that, in the thickness direction of the dielectric layer, the distance from the tip of the auxiliary electrode to the surface is less than or equal to half the thickness of one of the plurality of dielectric layers.

5. The ceramic electronic component according to any one of claims 1 to 4, characterized in that the auxiliary electrode has a plate shape.

6. The ceramic electronic component according to claim 5, characterized in that the auxiliary electrode has a plate shape with an aspect ratio of 1.5 to 15.

7. The ceramic electronic component according to claim 5, characterized in that the auxiliary electrode has a plate shape with an aspect ratio of 3.5 to 15.

8. Multiple dielectric layers and multiple internal electrode layers stacked alternately, Among the plurality of internal electrode layers, an auxiliary electrode protrudes from at least one surface of a pair of internal electrode layers facing each other across one of the plurality of dielectric layers into the interior of one of the plurality of dielectric layers, The auxiliary electrode has a substantially elliptical plate shape with a width that widens in a direction perpendicular to the direction in which the auxiliary electrode protrudes. A ceramic electronic component characterized in that, in the thickness direction of the dielectric layer, the distance from the tip of the auxiliary electrode to the surface is 1 / 10 or more of the thickness of one of the plurality of dielectric layers, and less than the thickness of one of the plurality of dielectric layers.

9. Multiple dielectric layers and multiple internal electrode layers stacked alternately, Among the plurality of internal electrode layers, an auxiliary electrode protrudes from at least one surface of a pair of internal electrode layers facing each other across one of the plurality of dielectric layers into the interior of one of the plurality of dielectric layers, The auxiliary electrode has a substantially elliptical plate shape with a width that widens in a direction perpendicular to the direction in which the auxiliary electrode protrudes. A ceramic electronic component characterized in that the aspect ratio of the auxiliary electrode is 1.5 to 15.

10. A process of adding boron nitride having a hexagonal crystal structure to a ceramic raw material, A step of producing a dielectric green sheet from the ceramic raw material to which the boron nitride has been added, A step of printing an internal electrode pattern on the surface of the dielectric green sheet using a metal conductive paste, A step of forming a laminate by stacking the dielectric green sheets on which the internal electrode pattern is printed, The process includes firing the laminate in a reducing atmosphere such that the boron nitride changes into voids and the metal conductive paste flows into the voids adjacent to the internal electrode pattern, A method for manufacturing ceramic electronic components, characterized in that, in the step of firing the laminate, the firing temperature is increased at a rate of 1000°C / hour or more within the range of 600 to 900°C.

11. The method for manufacturing ceramic electronic components according to claim 10, characterized in that the boron nitride particles have a plate shape with an aspect ratio of 1.5 to 15.

12. The method for manufacturing a ceramic electronic component according to claim 10 or 11, characterized in that, in the step of adding the boron nitride to the ceramic raw material, the concentration of the boron nitride relative to the ceramic raw material is 0.01 to 0.30 (wt%).

13. A method for manufacturing ceramic electronic components according to any one of claims 10 to 12, characterized in that, in the step of firing the laminate, the firing temperature is increased at a rate of 300°C / hour or less within the range of 1000 to 1200°C.

Images