Multilayer ceramic electronic component and method for manufacturing the same

Abstract

To provide a multilayer ceramic electronic component in which a plating film is formed as a uniform continuous film at a predetermined plating portion in the case of forming an external terminal electrode by direct plating onto a front surface of a ceramic element, and a manufacturing method of the same.SOLUTION: A multilayer ceramic electronic component comprises: an element component 2 having an almost rectangular effective layer part A and a pair of cover layer parts B1 and B2 where the effective layer part A is positioned on both sides of a thickness direction of the effective layer part A; and a pair of external electrodes 3. The effective layer part A includes a plurality of inner electrode layers 5 and a plurality of first ceramic layers 4a. The plurality of inner electrode layers 5 and the plurality of first ceramic layers 4a are alternately laminated. The plurality of inner electrode layers 5 are exposed from a pair of end surfaces 8 for each polarity, respectively. Each of the pair of cover layer parts B1 and B2 includes a mixing region 25 where an anchor conductor 6 and a second ceramic layer 4b are mixed. The mixing region 25 is exposed to at least a pair of end surfaces 8 and a pair of main surfaces 7 of the element component 2. An exposure part of the inner electrode layer 5 of the effective layer part A and an exposure part of the mixing region 25 of the cover layer parts B1 and B2 are connected to the external electrodes 3.SELECTED DRAWING: Figure 2A

Description

Technical Field

[0001] The present disclosure relates to a multilayer ceramic electronic component having a thin-film external electrode and a method for manufacturing the same.

Background Art

[0002] The external terminal electrode of a multilayer ceramic capacitor has been formed by dipping and applying an external electrode paste in a paste pool on the end face of a ceramic body and baking it. However, since there are a glass phase and voids that do not contribute to conductivity in the baked external electrode, an external electrode with a thickness exceeding 20 μm is formed, and it has been difficult to form a thin-film external electrode with a thickness of 20 μm or less.

[0003] In Patent Document 1, a method of directly forming an external electrode by plating has been proposed. According to this method, a plating film is deposited with the exposed portion of the internal electrode on the end face of the ceramic body as a nucleus, and as the plating film grows, the exposed portions of adjacent internal electrodes are connected. Therefore, compared with the conventional method of baking a conductive paste, a thinner external electrode is obtained.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the prior art of Patent Document 1, since the distance between the exposed portions of the anchor conductors, which are called adjacent anchor tabs, must be made closer toward the top and bottom surfaces in the stacking direction, it is necessary to prepare a variety of thicknesses of the ceramic green sheet on which the anchor conductors are laid. Therefore, there is a problem that the manufacturing becomes complicated and the man-hours and manufacturing costs increase. The anchor conductor is a dummy electrode not involved in capacitance formation, and its exposed portion serves as a plating growth starting point, forms a plating film that becomes an external electrode, and fixes the plating film to the ceramic element body of the main body.

[0006] In such prior art, when forming an external electrode directly by plating on the surface of a ceramic element body, it is difficult to grow the plating film as a continuous film with a uniform thickness at a predetermined plating site and efficiently form the external electrode with a high adhesion strength. Therefore, there is a demand for a multilayer ceramic electronic component and a method for manufacturing the same that can efficiently form an external electrode having a high adhesion strength by forming the plating film as a continuous film with a uniform thickness at a predetermined plating site.

Means for Solving the Problems

[0007] The multilayer ceramic electronic component of the present disclosure includes a substantially rectangular parallelepiped effective layer portion, a component body having a pair of cover layer portions positioned on both sides of the effective layer portion in the thickness direction of the effective layer portion, and a pair of external electrodes. The effective layer portion has a plurality of internal electrode layers and a plurality of first ceramic layers, and the plurality of internal electrode layers and the plurality of first ceramic layers are alternately stacked. The plurality of internal electrode layers are exposed from a pair of end faces according to polarity. Each of the pair of cover layer portions has a mixed region in which an anchor conductor and a second ceramic layer are mixed. The mixed region is exposed at least on the pair of end faces and a pair of main faces of the component body. The exposed portion of the internal electrode layer of the effective layer portion and the exposed portion of the mixed region of the cover layer portion are connected to the pair of external electrodes.

[0008] The manufacturing method of the multilayer ceramic electronic component of the present disclosure includes a substantially rectangular parallelepiped body component and a pair of external electrodes. In the manufacturing method of the multilayer ceramic electronic component, the body component forms an effective layer portion by alternately laminating ceramic green sheets having internal electrode layers with different polarities, and includes a cover layer portion for protecting the effective layer portion. The cover layer portion is formed by laminating a ceramic green sheet to which an anchor conductor paste accompanied by sheet attack is applied to the ceramic green sheet, and after firing and chamfering the body component, direct plating is performed to form an underlayer of the external electrode.

Effect of the Invention

[0009] According to the multilayer ceramic electronic component of the present disclosure, on the surface of the second ceramic layer, a plating film is bonded to the exposed portion of the mixed region that is exposed in close proximity, and a thin-layer external electrode with strong adhesion strength is formed. Therefore, a higher-functional multilayer ceramic electronic component with an external electrode formed with high adhesion strength can be efficiently provided in a defined standard size.

[0010] According to the manufacturing method of the multilayer ceramic electronic component of the present disclosure, when direct plating is performed, there is no area where the distance between the exposed conductors is wide. Therefore, plating grows starting from the closely scattered conductor exposed portions, and a plating film with excellent adhesion strength can be efficiently formed.

Brief Description of the Drawings

[0011]

Figure 1A

Figure 1B

Figure 2A

Figure 2B

Figure 3A

Figure 3B

Figure 4A

Figure 4B

Figure 5A

Figure 5B

Figure 5C

Figure 6A

Figure 6B

Figure 7

Figure 8

Figure 9A

Figure 9B

Figure 9C

Figure 10

Figure 11

Figure 12A

Figure 12B

Figure 13A

Figure 13B

Figure 13C

Embodiments for Carrying Out the Invention

[0012] Hereinafter, with reference to the drawings, embodiments of the multilayer ceramic electronic component and its manufacturing method of the present disclosure will be described by giving a plurality of examples of a multilayer ceramic capacitor which is a multilayer ceramic electronic component. The multilayer ceramic electronic component targeted by the present disclosure is not limited to a multilayer ceramic capacitor as long as it is an electronic component having a surface electrode on the main surface, and can also be applied to various multilayer ceramic components such as multilayer piezoelectric elements, multilayer thermistor elements, multilayer chip coils, and ceramic multilayer substrates.

[0013] FIG. 1A is a perspective view showing an example of a multilayer ceramic electronic component according to an embodiment of the present disclosure. The drawings referred to hereinafter are schematic, and the dimensional ratios and the like shown in the drawings are not necessarily accurately illustrated. Also, in this specification, a rectangular coordinate system XYZ is defined for convenience.

[0014] The multilayer ceramic capacitor 1A of this embodiment includes a body component 2 having a substantially rectangular parallelepiped effective layer portion A and a pair of cover layer portions B1 and B2 located on both sides in the third direction Z which is the thickness direction of the effective layer portion A, and a pair of external electrodes 3. The effective layer portion A has a plurality of internal electrode layers 5 and a first ceramic layer 4a that constitutes the first ceramic layer alternately laminated, and the internal electrode layer 5 is exposed on each of the pair of end faces 8. Each of the pair of cover layer portions B1 and B2 has a mixed region 25 in which an anchor conductor 6 and a second ceramic layer 4b that constitutes the second ceramic layer are mixed, and the mixed region 25 is exposed at least on the pair of end faces 8 and the pair of main faces 7. The exposed portions of the internal electrode layer 5 (see FIGS. 2A and 2B) of the effective layer portion A and the exposed portions of the mixed region 25 of the cover layer portions B1 and B2 are connected to the external electrode 3.

[0015] FIG. 1B is a perspective view showing a modified example of the multilayer ceramic electronic component of the embodiment of the present disclosure. The multilayer ceramic capacitor 1B which is the multilayer ceramic electronic component of this embodiment is different from the multilayer ceramic capacitor 1A of the foregoing embodiment only in that the positions of the mixed region 25 and the external electrode 3 are different, and other configurations are the same. Therefore, corresponding configurations are denoted by the same reference numerals, and overlapping descriptions are omitted. In the multilayer ceramic capacitor 1B of this embodiment, the mixed region 25 is exposed at least on the pair of side faces 9 and the pair of main faces 7. The exposed portions of the internal electrode layer 5 of the effective layer portion A and the exposed portions of the mixed region 25 of the cover layer portions B1 and B2 are connected to the external electrode 3.

[0016] Both the multilayer ceramic capacitor 1A in FIG. 1A and the multilayer ceramic capacitor 1B in FIG. 1B have a substantially rectangular parallelepiped body component 2 and an external electrode 3. The body component 2 has an internal electrode layer 5. The internal electrode layer 5 is exposed at a pair of end faces 8 facing in the first direction X and is connected to the external electrode 3. In the multilayer ceramic capacitor 1A in FIG. 1A, the external electrode 3 wraps around from the end face 8 of the body component 2 to the adjacent main face 7 and each side face 9, and in the multilayer ceramic capacitor 1B in FIG. 1B, it wraps around from each side face 9 to the adjacent main face 7.

[0017] The length in the X direction of the portion of the mixed region 25 exposed on the side surface may be substantially the same as the length in the X direction of the portion of the internal electrode layer 5 exposed on the side surface.

[0018] Simultaneously with the miniaturization of the component, the thickness of the external electrode 3 has become thinner, and it is also possible to form the external electrode 3 by directly plating the portion of the external electrode 3.

[0019] Figures 2A and 2B are perspective views of the base component before direct plating of the present disclosure. Each of the base components shown in Figures 2A and 2B corresponds to the multilayer ceramic capacitors 1A and 1B of Figures 1A and 1B. The internal electrode layer 5 is exposed in a layered manner on the end face 8 or the side face 9, and the exposed portions of the anchor conductor 6 of the anchor conductor layer portion are exposed in a scattered manner in proximity on the main face 7, the end face 8, or the side face 9. Therefore, the exposed portions of the internal electrode layer 5 and the anchor conductor 6 are arranged in a plurality of rows in the stacking direction of the third direction Z. As a result, when direct plating is performed, since there is no region where the interval between the exposed anchor conductors 6 is wide, the plating film of the external electrode 3 grows starting from the exposed portions of the adjacent internal electrode layer 5 and the exposed portions of the anchor conductor 6 scattered in proximity, and a plating film with a uniform thickness is formed.

[0020] Furthermore, since the conventional anchor layer was layered, there was a case where the plating film was peeled off layer by layer of the anchor layer particularly on the main face. However, in the present disclosure, since the plating film is connected to the anchor conductors existing in a mesh shape inside the base component through the exposed portions of the anchor conductors, a plating film with excellent adhesion strength is formed.

[0021] Figure 3A is an enlarged cross-sectional view of a part of the base component as seen from the cutting plane line IIIA-IIIA of Figure 2A, and Figure 3B is an enlarged cross-sectional view of a part of the base component as seen from the cutting plane line IIIB-IIIB of Figure 2B. Figure 3A shows an enlarged cross-section of the ridge line portion between the main face 7 and the end face 8 of the multilayer ceramic capacitor 1A, and Figure 3B shows an enlarged cross-section of the ridge line portion between the main face 7 and the side face 9 of the multilayer ceramic capacitor 1B. The cross-section of the anchor conductor 6 between the second ceramic layers is curved. The two-dot chain line 20 in the figure conceptually shows the surface position after chamfering.

[0022] Figure 3B shows the state where the base component 2 in Figure 3A is fired, chamfered, and then a plating layer is directly formed. The exposed parts of the conductors on the surface after firing and barrel polishing of the base component 2 are scattered in small loop shapes on the main surface 7 side, and exist in a zigzag linear shape with a changing exposed width on the side surface 9 side. Since the respective exposed conductors are close to each other, a plating film that grows with them as nuclei is deposited and grown, and adjacent exposed conductors are connected to form a uniform plating film.

[0023] The uniform plating film obtained by the base component 2 serves as the base electrode of the external electrode 3. However, in this state, since the bonding force between the conductor exposed part and the plating film is weak, it is advisable to perform a high-temperature treatment. When the internal electrode layer 5 and the anchor conductor 6 are made of Ni and a Cu plating film is formed by electroless plating, high-temperature annealing is performed at 600°C to 1000°C under a low oxygen partial pressure. Due to the high-temperature annealing, mutual diffusion between Cu and Ni occurs, and the bonding between the two becomes stronger.

[0024] With reference to FIGS. 4A and 4B, a method for forming the zigzag anchor conductor 6 will be described. FIG. 4A shows an enlarged cross-section of a printed body of the internal electrode paste. A thin-layer ceramic green sheet 10 formed on a resin sheet 16 such as PET is prepared, and a conductive paste 22 for the internal electrode layer is printed thereon in a predetermined pattern. The layer of the conductive paste 22 for the internal electrode layer is an alignment layer parallel to the ceramic green sheet 10. For example, the thickness of the resin sheet 16 is 20 μm to 30 μm, the thickness of the ceramic green sheet 10 is 0.5 μm to 2 μm, and the thickness of the conductive paste 22 for the internal electrode layer after printing and drying is 0.5 μm to 2 μm. The conductive paste 22 for the internal electrode layer is obtained by mixing conductor metal powders such as Ni, Pd, Cu, and Ag, a sintering suppression auxiliary agent, and a resin binder in a solvent and kneading them.

[0025] FIG. 4B shows an enlarged cross-section of a printed body of the anchor conductor 6 used in the multilayer ceramic capacitors 1A and 1B of the embodiment of the present disclosure. The conductive paste 23 for the anchor conductor is printed in a predetermined pattern on the ceramic green sheet 10 in the same process as in FIG. 4A. As the solvent of the conductive paste 23 for the anchor conductor, a solvent that swells and dissolves the ceramic green sheet 10 is used. Due to the solvent contained in the conductive paste 23 for the anchor conductor, swelling and deformation occur, and after drying, the anchor conductor 6 and the ceramic green sheet 10 become mixed on the resin sheet 16 due to the sheet attack phenomenon. Concavities and convexities are formed on the surface of the conductive film. By laminating and pressing such mixed sheets, the bent anchor conductor 6 as shown in FIG. 3A is obtained.

[0026] In the present embodiment, the sheet attack phenomenon refers to a phenomenon in which when a conductive paste is applied on a ceramic green sheet, the organic solvent in the conductive paste dissolves the binder component contained in the ceramic green sheet. In recent years, further increase in capacitance has been demanded for multilayer ceramic capacitors, and further multilayerization and thinning have been studied. However, in such a multilayer ceramic capacitor with advanced thinning, when holes or wrinkles occur in the ceramic layer due to the sheet attack phenomenon, a problem occurs in that desired electrical characteristics cannot be obtained.

[0027] The solvent contained in the conductive paste 23 for the anchor conductor is a solvent having good compatibility with the ceramic green sheet 10. For example, any one of solvents such as decanol, tridecanol, terpineol, dihydroterpineol, butyl carbitol, butyl, carbitol acetate, butyl cellosolve, and butyl cellosolve acetate is used as the main solvent.

[0028] Figs. 5A to 5C are perspective views showing printed bodies used when manufacturing a green body part before firing. Fig. 5A is a perspective view showing a ceramic green sheet on which a pattern of an anchor conductor is printed. Figs. 5B and 5C are perspective views showing ceramic green sheets on which patterns of internal electrode layers with different polarities are printed. A printed body is a ceramic green sheet 10 on which an anchor conductor 6 or an internal electrode layer 5 is printed. In the printed body of Fig. 5A, the area where the anchor conductor 6 exists is mixed with the ceramic green sheet 10. The internal electrode layer 5 is formed by printing on the ceramic green sheet 10 with a predetermined electrode pattern.

[0029] Fig. 6A is an exploded perspective view schematically showing the laminated state of green sheets. After laminating the ceramic green sheets 10 on which the anchor conductor 6 and the internal electrode layer 5 are printed, pressure is applied to obtain a large mother laminate 11 as shown in Fig. 7. By cutting the mother laminate 11 longitudinally and transversely with a predetermined dimension at the position of a cutting line 12 drawn by a broken line, individual green body parts 2 can be obtained.

[0030] Fig. 6B is an exploded perspective view showing another example of the green sheet. Each ceramic green sheet 10 in Fig. 6B is substantially the same as the laminated pattern of the ceramic green sheet 10 in Fig. 5A, but a blank sheet 10a of the ceramic green sheet is inserted between the anchor conductor 6 and the internal electrode layer 5. It is preferable to increase the distance from the anchor conductor 6 closest to the effective layer A in the lamination direction to the internal electrode layer 5 adjacent to the anchor conductor 6 in the lamination direction. Also, if the solvent contained in the anchor conductor 6 oozes out and reaches the internal electrode layer 5, the internal electrode layer 5 will melt and deform. Therefore, by interposing the blank sheet 10a, the distance between the anchor conductor 6 and the internal electrode layer 5 can be increased. There is an effect of preventing the possibility that the solvent of the anchor conductor 6 seeps out after lamination and adversely affects the effective layer portion A that greatly affects the electrical characteristics. The inserted ceramic green sheet 10 may be different from the internal electrode layer 5 as long as it does not affect the electrical characteristics. It may be a single layer or a plurality of layers.

[0031] Note that the blank sheet 10a in FIG. 6B may be a green sheet using a binder with low wettability to the solvent contained in the anchor conductor 6. Since the penetration of the solvent of the anchor conductor 6 into the effective layer portion A can be blocked without increasing the thickness of the blank sheet 10a, there is an effect of reducing the reduction in the number of laminated blank sheets 10a of the effective layer portion A and the number of laminated blank sheets 10a.

[0032] Next, with reference to FIGS. 7 and 8, a second embodiment will be described. FIG. 7 is a perspective view showing a mother laminate pair, and FIG. 8 is a perspective view showing a multilayer ceramic electronic component according to the second embodiment of the present disclosure. In the present embodiment, as shown in FIG. 8, a multilayer ceramic capacitor having external electrodes 3 on six surfaces of each pair of main surfaces 7, end surfaces 8, and side surfaces 9 is taken as an example, and a side protection sheet is attached later after lamination to form an element component 2.

[0033] FIGS. 9A to 9C show a ceramic green sheet printed with an anchor conductor paste. FIG. 9A shows a green sheet printed with a pattern of an anchor conductor, and FIGS. 9B and 9C show ceramic green sheets 102 and 103 printed with patterns of internal electrode layers 5 having different polarities. The area where the anchor conductor 6 exists in FIG. 9A is a mixture of the anchor conductor 6 and the ceramic green sheet 101.

[0034] FIG. 10 is an exploded perspective view schematically showing the laminated state of the printed bodies shown in FIGS. 5A to 5C. After lamination, it is pressed to obtain a large mother laminate 11 as shown in FIG. 11, and is cut vertically and horizontally along a cutting planned line 12 of a predetermined dimension to obtain a pre-form body 13 of FIG. 12A.

[0035] FIG. 12A is an exploded perspective view showing a state where a protective layer 14 is attached to a side surface 9 of a green body precursor 13 with an internal electrode layer 5 exposed. FIG. 12B is a perspective view showing a green body component 2 with the protective layer 14 attached to the green body precursor 13. The exposed portions of the anchor conductors 6 are scattered with exposed portions forming a small circular, elliptical, or loop shape close to an oval on the main surface 7, and a plurality of linear exposed portions that are zigzag while changing the exposure width exist on the side surface 9.

[0036] The green body precursor 13 is fired, chamfered by barrel polishing, a base layer of the external electrode 3 is formed by direct plating, and an outer layer of the external electrode 3 is formed on the base layer by electrolytic plating, whereby the multilayer ceramic capacitor of FIG. 8 can be obtained. Such a multilayer ceramic capacitor having no external electrode 3 on the side surface 9 can be arranged in close proximity to each other on a circuit board on which they are mounted, thereby improving the mounting density of components.

[0037] The external electrode 3 may be formed by laying an electrolytic Ni plating layer serving as a barrier layer against solder after high-temperature annealing of the directly plated base layer, and laying an electrolytic Sn plating layer for ensuring solder wetting property on the surface layer.

[0038] Hereinafter, taking the green body component 2 of FIG. 1A as an example, its manufacturing method will be described.

[0039] First, a ceramic mixed powder obtained by adding an additive to BaTiO3, which is a ceramic dielectric material, is wet-milled and mixed with a bead mill. A polyvinyl butyral-based binder, a plasticizer, and an organic solvent are added to and mixed with this milled and mixed slurry to prepare a ceramic slurry.

[0040] Next, using a die coater, the sheet material of the ceramic green sheet 10 is formed on the carrier film. The thickness of the sheet material of the ceramic green sheet 10 is, for example, 1 μm or more and less than 10 μm. The thinner the thickness of the sheet material of the ceramic green sheet 10, the higher the capacitance of the multilayer ceramic capacitor can be. The forming of the sheet material of the ceramic green sheet 10 is not limited to only a die coater, and for example, it may be performed using a doctor blade coater or a gravure coater or the like.

[0041] The thickness of the sheet material of the ceramic green sheet 10 is desirably 10 μm or less. When forming the external electrode 3 by direct plating, plating grows with the layer end of the internal electrode layer 5 exposed on the side surface 9 of the element body 2 as a nucleus and forms a plating film combined with the plating that grows at the layer end of the adjacent internal electrode layer 5. Therefore, if the interval between the internal electrode layers 5 is 10 μm or more, the continuity of the plating film may be impaired.

[0042] On the other hand, a conductive paste 22 for the internal electrode layer is prepared. The conductive paste 22 for the internal electrode layer is, for example, a mixture obtained by putting metal powders such as Ni, Pd, Cu, Ag, or alloy powders thereof and a resin binder into a solvent and kneading them, and ceramic fine powders such as BaTiO3 for controlling sintering may be added.

[0043] As the solvent used for the conductive paste 22 for the internal electrode layer, a solvent that is not compatible with the sheet material of the ceramic green sheet 10 is used. If sheet attack caused by the solvent occurs with respect to the sheet material of the ceramic green sheet 10, it will cause a short circuit. Sheet attack refers to a phenomenon in which when the paste for the internal electrode contacts the sheet material of the ceramic green sheet 10, the organic solvent of the conductive paste 22 for the internal electrode layer dissolves the organic binder of the sheet material of the ceramic green sheet 10.

[0044] The conductive paste 22 for the internal electrode layer is obtained by, for example, putting metal powders such as Ni, Pd, Cu, Ag, or alloy powders containing them, and a resin binder together with a dispersant into a solvent and kneading them, and ceramic fine powders such as BaTiO3 for controlling sintering may be added.

[0045] As the solvent of the conductive paste 23 for the anchor conductor, a solvent having good compatibility with the sheet material of the ceramic green sheet 10 is used. For example, any one of solvents such as decanol, tridecanol, terpineol, dihydroterpineol, butyl carbitol, butyl carbitol acetate, butyl cellosolve, and butyl cellosolve acetate may be used as the main solvent.

[0046] Next, as shown in FIGS. 11 to 13, the internal electrode pattern and the anchor conductor pattern are printed in a predetermined pattern on the sheet material of the ceramic green sheet 10 using the gravure printing method. The printing of the conductive paste is not limited to the gravure printing method, and for example, the screen printing method or the like may be used. The actual printing pattern is printed on a large green sheet using a plate having a large number of individual electrode patterns.

[0047] The conductive paste 23 for the anchor conductor is printed on the layer of the anchor conductor 6, and the conductive paste 22 for the internal electrode layer is printed on the sheet material of the ceramic green sheet 10 in the effective layer portion A. After printing, the printed conductive paste 22 for the internal electrode layer is dried. However, at the location where the conductive paste 23 for the anchor conductor is printed, three-dimensional micro wrinkles are generated by sheet attack when viewed from the surface.

[0048] Next, a ceramic green sheet 10 printed with the internal electrode layer 5 and the anchor conductor 6 is laminated. FIG. 10 is an exploded perspective view schematically showing the laminated state of the ceramic green sheet 10 printed with the internal electrode layer 5 and the anchor conductor 6. On the support sheet 18, ceramic green sheets 10 printed with a predetermined number of conductive pastes 23 for the anchor conductor are laminated. Next, with a blank sheet 10a interposed therebetween, ceramic green sheets 10 having two types of internal electrode layers 5 with different polarities and stacked alternately are laminated alternately, and finally, after sandwiching the blank sheet 10a, ceramic green sheets 10 printed with a predetermined number of conductive pastes 23 for the anchor conductor are laminated. Note that the support sheet 18 may be an adhesive release sheet capable of adhesion and peeling, such as a weak adhesive sheet or a foamed release sheet.

[0049] In order to reduce the possibility that the solvent of the layer of the conductive paste 23 for the anchor conductor oozes out after lamination and adversely affects the effective layer portion A, the blank sheet 10a is inserted to increase the distance to the effective layer portion A, thereby enhancing the reliability of the component. The inserted blank sheet 10a may be a single layer or a plurality of layers.

[0050] Next, the laminate is pressure-bonded in a pressing process to obtain an integrated mother laminate 11 as shown in FIG. 11. The pressing of the mother laminate 11 can be performed using, for example, a hydrostatic pressure pressing apparatus. Heating may be performed during pressing to accelerate the adhesion of the ceramic green sheet 10. The phantom line 12 shown in FIG. 12 is a planned cutting line indicating the cutting position. Note that under the mother laminate 11, the support sheet 18 used when laminating the ceramic green sheet 10 is positioned.

[0051] Next, using a punching cutting device, the mother laminate 11 is cut to a predetermined dimension to obtain the elementary body precursor 13 of FIG. 1A or FIG. 1B. Note that the method of cutting the mother laminate 11 is not limited to the method using a punching cutting device, and for example, a dicing saw or the like may be used.

[0052] Next, the green body component 2 is degreased and sintered in a firing process. Degreasing is performed by heating the green body component 2 to 700 °C in a nitrogen atmosphere furnace, and then sintering is carried out by controlling the peak temperature to 1100 - 1250 °C in a reduction furnace with a hydrogen atmosphere to sinter the green body component 2.

[0053] Next, chamfering is performed by barrel polishing. The barrel polishing is carried out using a wet barrel in which a plurality of green body components 2 are placed together with an abrasive such as ceramic powder in a rotating pot and polished in water. FIGS. 2A and 2B are perspective views of the green body component 2 after chamfering. After chamfering, the green body component 2 has rounded edges and apex angles. All surfaces are polished, and a certain amount of the surface layer of the six sides is shaved off and removed. The exposed portions of the conductor on the surface after barrel polishing are small loop-shaped exposed portions scattered on the main surface 7 side as described above, and on the side surface 9 side, there are also zigzag linear exposed portions while changing the exposure width.

[0054] After chamfering, electroless plating is applied to the green body component 2 to form a copper plating film that serves as the base for the external electrode 3. The copper plating film grows with the exposed ends of the conductor of the internal electrode layer 5 and the anchor conductor 6 as nuclei. Since there is no large space in the empty space between the exposed conductors of both the anchor electrode portion and the internal electrode layer 5, that is, the conductor exposed portions are formed at a high density, the plating film of the direct plating precipitates and grows with these conductor exposed portions as nuclei, and the adjacent portions of the exposed conductors are connected at a high density to form a plating layer with a uniform thickness. The electroless plating may be a metal other than copper plating, such as Pd or Ni plating. After plating, annealing may be performed at a high temperature of 600 °C - 900 °C to form an alloy at the joint with the internal electrode layer 5 mainly composed of Ni, thereby increasing the bonding strength between the internal electrode layer 5 and the plating film.

[0055] Furthermore, in order to facilitate soldering, a plurality of plated outer layers with a Ni layer and a Sn layer or the like stacked may be provided. Through the above steps, the multilayer ceramic capacitors 1A and 1B as shown in FIGS. 2A and 2B are completed.

[0056] Next, a second embodiment will be described. FIGS. 6A and 6B are perspective views of an example of a multilayer ceramic capacitor in which the external electrode 3 extends from the end face 8 to the main face 7. Note that the same reference numerals are given to the parts corresponding to the above-described embodiment.

[0057] The process of preparing the sheet material of the ceramic green sheet 10 and the conductive paste 23 for the anchor conductor is as described in the first embodiment.

[0058] Using these materials, as shown in FIGS. 13A to 13C, the internal electrode pattern and the anchor conductor pattern are printed on the sheet material of the ceramic green sheet 10 created above by the gravure printing method to form the conductive paste 23 for the anchor conductor that becomes the internal electrode layer 5 in a predetermined pattern. The printing of the conductive paste for the anchor conductor is not limited to the gravure printing method, and for example, it may be performed using a screen printing method or the like. The actual printing pattern is printed on a large green sheet using a plate having a large number of individual electrode patterns.

[0059] The conductive paste 23 for the anchor conductor is printed on the anchor conductor layer, and the conductive paste 22 for the internal electrode layer is printed on the internal electrode sheet on the sheet material of the ceramic green sheet 10 in the effective layer portion A. After printing, the printed paste is dried. However, micro wrinkles are generated on the surface where the conductive paste 23 for the anchor conductor is printed. If cracks are observed, they are prevented by controlling the solvent type, solvent amount, and drying time of the conductive paste 23 for the anchor conductor.

[0060] Next, the ceramic green sheets 10 on which the internal electrode layer 5 and the conductive paste 23 for the anchor conductor are printed are laminated. FIG. 12A schematically shows the laminated state. Support sheet 18 The printed ceramic green sheet 10 is laminated. After inserting the blank sheet 10a, the ceramic green sheets 10 having two types of patterns with different polarities and a predetermined number of sets are alternately laminated, and the blank sheet 10a is inserted. Finally, the ceramic green sheets 10 printed with a predetermined number of conductive pastes 22 for the internal electrode layer and the conductive paste 23 for the anchor conductor are laminated.

[0061] The anchor conductor 6 is formed by drying the conductor paste on the ceramic green sheet, but it is undeniable that there is a remaining solvent component. If the remaining solvent component affects the effective layer, the ceramic green sheet of the effective layer may be deformed and the insulation may deteriorate. The blank sheet 10a of the ceramic green sheet is inserted between the anchor conductor 6 and the effective layer portion A to enhance the reliability, and a plurality of layers may be used. The support sheet 18 may be an adhesive release sheet capable of adhesion and peeling, such as a weak adhesive sheet or a foamed release sheet.

[0062] Next, the laminate is crimped in a pressing process to obtain an integrated mother laminate 11 as shown in FIG. 11. The pressing of the mother laminate 11 can be performed using, for example, a hydrostatic press device. The mother laminate 11 may be heated during pressing to bring the ceramic green sheets 10 into close contact with each other and accelerate the pressing time. The virtual line 12 in FIG. 11 is a cutting planned line indicating the cutting position. Although omitted in FIGS. 6A and 6B, a support sheet 18 used when laminating the ceramic green sheets 10 is located under the mother laminate 11.

[0063] Next, using a die-cutting device, the mother laminate 11 can be cut at a predetermined dimension along the cutting planned line 12 to obtain a body precursor 13 shown in FIG. 12A. The method of cutting the mother laminate 11 is not limited to the method using a die-cutting device, and for example, a dicing saw device may be used. The first surface 11a and the second surface 11b, the end surface 8 and the side surface 9 of the mother laminate 11 respectively correspond to the first surface 7A and the second surface 7B, the end surface 8, and the side surface 9 of the body component 2.

[0064] As shown by the base precursor 13 in Fig. 12B, in the anchor conductor part, the conductive paste 23 for the anchor conductor causes sheet attack on the ceramic green sheet 10, and the conductor layer and the ceramic layer of the ceramic green sheet 10 are mixed.

[0065] The formation of the protective layer 14 will be described with reference to Figs. 13A to 13C.

[0066] Fig. 13A is a front view showing a state in which one side surface 9 of the base precursor 13 is reversely fixed to the pedestal 24 via a peelable adhesive support sheet 18.

[0067] Fig. 13B is a front view showing a state in which the base precursor 13 is pressed against the ceramic green sheet 10 on the resin film 27. In this state, the ceramic green sheet 10 is attached to the side surface 9. To increase the adhesion force, it may be made into an adhesive ceramic green sheet, or heated at 40°C to 60°C during crimping, or an adhesive medium material that does not affect the final product may be used. The ceramic green sheet 10 before printing that will become the protective layer 14 may be a single-layer ceramic green sheet or a multi-layer ceramic green sheet. In such a case, the multi-layer ceramic green sheets 10 may have different components from each other.

[0068] Fig. 13C is a front view showing a state in which the ceramic green sheet 10 pressed against the side surface 9 of the base precursor 13 is pulled up. The surface of the ceramic green sheet 10 that is not in contact with the base component 2 of the sheet material remains on the resin sheet 16. Therefore, in this case, a sheet material of the ceramic green sheet 10 having a low breaking strength may be used.

[0069] After pasting the ceramic green sheet 10 on both sides or during the pasting process, the body part 2 may be further pressure-bonded by pressing to firmly adhere the sheet material of the ceramic green sheet 10 that becomes the protective layer 14. The perspective view of Fig. 12B shows the state of the body part 2 with the sheet material of the ceramic green sheet 10 having the protective layer 14 laid on the side surface 9 pasted thereon.

[0070] Note that the formation of the protective layer 14 is not limited to pasting on the side surface 9 of the body precursor 13. For example, it may be formed by applying a ceramic slurry to the side surface 9 and then drying.

[0071] The processes after the firing process are the same as those in the first embodiment, so detailed descriptions are omitted.

[0072] As described above, the embodiments of the present disclosure have been described in detail. However, the present disclosure is not limited to the above-described embodiments, and various changes, improvements, etc. are possible within the scope not departing from the gist of the present disclosure. Needless to say, all or part of each of the above embodiments can be combined as appropriate within a non-contradictory range.

Explanation of Reference Numerals

[0073] 1, 1A, 1B Multilayer ceramic capacitor 2 Body part 3 External electrode 4a, 4b Dielectric ceramic 5 Internal electrode layer 6 Anchor conductor 7 Main surface 8 End face 9 Side surface 10 Ceramic green sheet 11 Mother laminate 12 Scheduled cutting line 13 Body precursor 14 Protective layer 16 Resin sheet 17 Plating growth starting point 18 Support sheet 20 Surface position after polishing 22 Conductive paste for internal electrodes 23 Conductive paste for anchor conductors 24 Base 25 Mixed region A Active layer section B1, B2 Cover layer section

Claims

1. A body component having a substantially rectangular parallelepiped effective layer portion and a pair of cover layer portions located on both sides in the thickness direction of the effective layer portion, and a pair of external electrodes, The effective layer portion has a plurality of internal electrode layers and a plurality of first ceramic layers, Each of the plurality of internal electrode layers and the plurality of first ceramic layers is alternately laminated, and the plurality of internal electrode layers are exposed from a pair of end faces of the body component according to polarity, Each of the pair of cover layer portions has a plurality of anchor conductors and a plurality of second ceramic layers that are laminated, and further has a mixed region in which the plurality of anchor conductors and the plurality of second ceramic layers are mixed, The mixed region is exposed at least on the pair of end faces and a pair of main faces of the body component, and includes the plurality of bent anchor conductors in a cross section perpendicular to the main face and the end face, An exposed portion of the internal electrode layer of the effective layer portion and an exposed portion of the mixed region of the cover layer portion are connected to the pair of external electrodes, and the pair of external electrodes includes a base layer formed on the body component by direct plating, a multilayer ceramic electronic component.

2. The multilayer ceramic electronic component according to claim 1, wherein a distance from the internal electrode layer of the effective layer portion to the anchor conductor is wider than a distance between adjacent internal electrode layers of the effective layer portion.

3. The multilayer ceramic electronic component according to claim 1 or 2, wherein the external electrode further includes a plating film covering the surface of the base layer.

4. The multilayer ceramic electronic component according to claim 3, wherein a main component of the base layer is Cu.

5. In a method for manufacturing a multilayer ceramic electronic component including a substantially rectangular parallelepiped body component and a pair of external electrodes, the body component having an effective layer portion formed by alternately laminating ceramic green sheets having internal electrode layers of different polarities and a cover layer portion for protecting the effective layer portion, The step of forming the cover layer portion by laminating a ceramic green sheet to which an anchor conductor paste accompanied by sheet attack is applied to the ceramic green sheet; The step of firing the base component; The step of polishing the fired base component to expose at least one of a plurality of anchor conductors formed by sintering the anchor conductor paste on a pair of end faces of the base component, and exposing at least one of the plurality of anchor conductors on a pair of main faces of the base component; A method for manufacturing a multilayer ceramic electronic component, including a step of directly plating the polished base component to form a base layer of the pair of external electrodes.

6. The method for manufacturing a multilayer ceramic electronic component according to claim 5, wherein the anchor conductor paste uses any one of decanol, tridecanol, terpineol, dihydroterpineol, butyl carbitol, butyl carbitol acetate, butyl cellosolve, and butyl cellosolve acetate as a main solvent.

7. The method for manufacturing a multilayer ceramic electronic component according to claim 5 or 6, including a step of inserting at least one layer of ceramic green sheet between the cover layer portion and the effective layer portion.

8. The method for manufacturing a multilayer ceramic electronic component according to claim 7, wherein the at least one layer of ceramic green sheet is a ceramic green sheet highly resistant to sheet attack caused by the solvent of the anchor conductive paste.

9. The method for manufacturing a multilayer ceramic electronic component according to claim 5, including a step of heating the base component at a temperature of 600 ° C or higher and 1000 ° C or lower after the direct plating.

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