Method for manufacturing multilayer ceramic electronic component

Abstract

This method for manufacturing a multilayer ceramic electronic component comprises a first step for alternately laminating a dielectric ceramic material and an internal electrode material to manufacture a laminate sheet, a second step for cutting the lamiante sheet to manufacture a laminate, a third step for removing the internal electrode material exposed from the cut surface of the laminate and an electroconductive material bonded to the dielectric ceramic material, and a fourth step for affixing a protective layer to the cut surface from which the electroconductive material is removed. In the third step, the dielectric ceramic material is preferentially vaporized with respect to the internal electrode material.

Description

Manufacturing method for multilayer ceramic electronic components

[0001] The present disclosure relates to a method for manufacturing a multilayer ceramic electronic component.

[0002] A method for manufacturing a multilayer ceramic capacitor is known from the prior art, as described in Japanese Patent Application Laid-Open No. 2003-222299.

[0003] JP 2018-98248 A

[0004] The method for manufacturing a multilayer ceramic electronic component according to the present disclosure includes a first step of alternately stacking dielectric ceramic materials and internal electrode materials to form a laminate sheet; a second step of cutting the laminate sheet to form a laminate; a third step of removing the internal electrode material exposed at the cut surface of the laminate and conductive material adhering to the dielectric ceramic material; and a fourth step of attaching a protective layer to the cut surface from which the conductive material has been removed, wherein in the third step, the dielectric ceramic material is vaporized preferentially over the internal electrode material.

[0005] 7A and 7B are perspective views showing a multilayer ceramic capacitor manufactured by a method for manufacturing a multilayer ceramic electronic component according to an embodiment of the present disclosure; FIG. 7B is a perspective view showing an element component of the multilayer ceramic capacitor; FIG. 7C is a perspective view showing a precursor of the element component; FIG. 7D is a schematic view showing a state in which a conductive paste is printed on a ceramic green sheet; FIG. 7E is an external view showing a state in which a plurality of ceramic green sheets on which internal electrode layers are printed are stacked; FIG. 7F is a perspective view showing a laminate divided by an imaginary dividing line; FIG. 7G is a perspective view showing a plurality of laminates cut by an imaginary dividing line; FIG. 7H is a perspective view showing the laminate of FIG. 7 rotated so that one of the side surfaces is open; FIG. 7I is a schematic view showing that the internal electrode layers are preferentially vaporized by irradiating the laminate with a low-power laser beam; FIG. 7I is a schematic view showing that the dielectric layers are preferentially vaporized by irradiating the laminate with a high-power laser beam; FIG. 7J is a view showing a process of attaching a protective layer to the side surface of the laminate; FIG. 7J is a view showing a process of attaching a protective layer to the side surface of the laminate; FIG. 7J is a view showing a process of attaching a protective layer to the side surface of the laminate; FIG. 7J is a perspective view showing a laminate on which a protective layer has been formed.

[0006] In the manufacturing process of a multilayer ceramic capacitor, for example, a base laminate is produced by alternately stacking dielectric ceramic layers and internal electrodes, and the base laminate is cut to produce a laminate in which the internal electrodes are exposed on the cut surface, and a protective layer is then formed on the cut surface. When the base laminate is cut, stress caused by the cutting can cause the internal electrodes to sag, resulting in contact across the layers. Patent Document 1 describes a method of removing metal components on the cut surface by etching or laser treatment.

[0007] When metal components on the cut surface are removed using a laser, as in the method described in Patent Document 1, the internal electrodes are rapidly heated and evaporated by laser light irradiation, causing metal particles to scatter around and adhere to the exposed surface of the dielectric layer, or resolidification material from the metal vapor immediately after laser irradiation may adhere to the exposed surface of the dielectric layer. If a protective layer is formed while leaving metal particles or resolidification material on the cut surface, a decrease in breakdown voltage and short circuits between the internal electrodes are likely to occur, and internal insulation may not be sufficiently ensured. Therefore, there is a need for a method for manufacturing a multilayer ceramic electronic component that can reduce sagging of internal electrodes and residual conductive material such as metal on the cut surface and reduce contamination of the cut surface of the dielectric ceramic layer by conductive material.

[0008] The present disclosure will be described below with reference to the drawings. A method for manufacturing a multilayer ceramic capacitor, which is an example of a multilayer ceramic electronic component, will be described below. The drawings used in the following description are schematic, and the dimensional ratios and the like in the drawings do not necessarily correspond to the actual ones. In the multilayer ceramic electronic component according to the embodiment, either direction may be considered as up or down, but in this specification, for convenience, a Cartesian coordinate system XYZ is defined in some of the drawings.

[0009] In the following description, the positive side in the Z-axis direction is referred to as the upper side, and terms such as upper surface and lower surface may be used. The X-axis direction is also referred to as the first direction or length direction. The Y-axis direction is also referred to as the second direction or width direction. The Z-axis direction is also referred to as the third direction, height direction, or stacking direction.

[0010] First, a multilayer ceramic capacitor manufactured by a method for manufacturing a multilayer ceramic electronic component according to an embodiment of the present disclosure will be described.

[0011] FIG. 1 is a perspective view showing a multilayer ceramic capacitor 1 manufactured by a method for manufacturing a multilayer ceramic electronic component according to an embodiment of the present disclosure, FIG. 2 is a perspective view showing an element component 2 of the multilayer ceramic capacitor 1 of FIG. 1, and FIG. 3 is a perspective view showing a precursor of the element component 2 of FIG. 2. FIG. 2 is a view showing the element component 2 after firing, but it is also a view showing the element component 2 before firing. The element component 2 after firing has shrunk due to firing, but it has the same structure as the element component 2 before firing. FIG. 3 is a view showing a laminate 13 after firing, but it is also a view showing the laminate 13 before firing.

[0012] A multilayer ceramic capacitor 1, which is a multilayer ceramic electronic component manufactured according to this embodiment, includes a laminate 13 and dielectric protection layers 6A and 6B. As shown in FIG. 1 , the multilayer ceramic capacitor 1 may also include a first external electrode 3A and a second external electrode 3B for electrical connection to the outside (e.g., a circuit board). As shown in FIG. 2 , the laminate 13 and the dielectric protection layers 6A and 6B constitute an element component 2. The laminate 13 is a precursor of the element component 2 and is also referred to as an element precursor 13. The dielectric protection layers 6A and 6B are also referred to as protection layers 6.

[0013] As shown in Fig. 3, the laminate 13 is configured by alternately stacking dielectric layers 4 and internal electrode layers 5 in a third direction (Z-axis direction). The laminate 13 may have a substantially rectangular parallelepiped shape. The laminate 13 has a first surface 7A and a second surface 7B that face each other in the third direction. The laminate 13 has a first end surface 8A and a second end surface 8B that face each other in the first direction (X-axis direction), and a first cut surface 9A and a second cut surface 9B that face each other in the second direction (Y-axis direction).

[0014] The first external electrode 3A and the second external electrode 3B may be collectively referred to as the external electrode 3. Furthermore, the first surface 7A and the second surface 7B may be collectively referred to as the main surface 7, the first end surface 8A and the second end surface 8B may be collectively referred to as the end surface 8, and the first cut surface 9A and the second cut surface 9B may be collectively referred to as the cut surface 9. Furthermore, the direction perpendicular to the cut surface 9 may be referred to as the normal direction.

[0015] The dielectric layer 4 is made of an insulating material, such as BaTiO ３ (barium titanate), CaTiO ３ (Calcium titanate), SrTiO ３ (strontium titanate), BaZrO ３ (barium zirconate), CaZrO ３ It may be made of a ceramic material such as calcium zirconate.

[0016] The thinner the dielectric layers 4, the greater the capacitance of the multilayer ceramic capacitor 1. The thickness of the dielectric layers 4 may be, for example, 0.5 μm to 10 μm. The internal electrode layers 5 are made of a conductive material. The internal electrode layers 5 may be made of a metal material such as Ni (nickel), Cu (copper), Ag (silver), Sn (tin), Pt (platinum), Pd (palladium), Au (gold), or an alloy material containing these metal materials.

[0017] 3, the internal electrode layers 5 are exposed on a first cut surface 9A and a second cut surface 9B. The internal electrode layers 5 have end portions 51 exposed on the cut surface 9, and the end portions 51 extend in a first direction. The internal electrode layers 5 are exposed on a first end surface 8A or a second end surface 8B depending on the polarity.

[0018] As long as the characteristics of the capacitor can be ensured, the thinner the thickness T of the internal electrode layers 5, the fewer internal defects caused by internal stresses there will be, and the more reliable the multilayer ceramic capacitor 1 will be. When the multilayer ceramic capacitor 1 is a capacitor with a large number of layers, the thickness T of the internal electrode layers 5 may be, for example, 0.4 μm to 1.0 μm.

[0019] The protective layer 6 is made of an insulating material, such as BaTiO ３ , CaTiO ３ , SrTiO ３ , BaZrO ３ , CaZrO ３ The protective layer 6 may be made of the same ceramic material as the ceramic material that forms the dielectric layer 4.

[0020] One protective layer 6A is located on the first cut surface 9A and covers the internal electrode layers 5 exposed on the first cut surface 9A. The other protective layer 6B is located on the second cut surface 9B and covers the internal electrode layers 5 exposed on the second cut surface 9B.

[0021] 1, the external electrodes 3 include a first external electrode 3A and a second external electrode 3B. The first external electrode 3A is located on the first end surface 8A and is electrically connected to the internal electrode layer 5 exposed at the first end surface 8A.

[0022] The second external electrode 3B is located on the second end surface 8B and is electrically connected to the internal electrode layer 5 exposed on the second end surface 8B. The external electrode 3 may extend around at least one of the first surface 7A and the second surface 7B.

[0023] The first external electrode 3A may extend onto the first cut surface 9A and the second cut surface 9B, covering a portion of the protective layer 6 closer to the first end surface 8A. The second external electrode 3B may extend onto the first cut surface 9A and the second cut surface 9B, covering a portion of the protective layer 6 closer to the second end surface 8B. The first external electrode 3A and the second external electrode 3B are electrically insulated from each other.

[0024] The external electrodes 3 may be composed of an underlayer connected to the element component 2 and a plated outer layer located on the underlayer. In this case, it is possible to improve adhesion between the external electrodes 3 and the element component 2 while facilitating solder mounting of the multilayer ceramic capacitor 1 to a circuit board. The underlayer may be applied and baked onto the element component 2 after firing, or it may be applied to the element component 2 before firing and fired simultaneously with the element component 2. The plated outer layer may be formed by a plating method such as electroless plating or electrolytic plating.

[0025] The underlayer may be formed by direct plating. The underlayer and the plated outer layer may each consist of a single layer or multiple layers. The underlayer and the plated outer layer may be made of a metal material such as Ni, Cu, Ag, Pd, or Au, or an alloy material containing these metal materials. The external electrode 3 may have a conductive resin layer. The conductive resin layer may be located between the underlayer and the plated outer layer, or may be located on the plated outer layer.

[0026] On the cut surface 9 of the laminate 13, an internal electrode layer 5 of a first polarity and an internal electrode layer 5 of a second polarity different from the first polarity are adjacent to each other with a dielectric layer 4 sandwiched therebetween.

[0027] In this embodiment, protective layers 6 for electrical insulation between the internal electrode layers 5 of opposite polarity and for physical protection of the ends 51 are located on the first cut surface 9A and the second cut surface 9B. The protective layers 6 may be made of a ceramic material, in which case the protective layers 6 can have insulating properties and relatively high mechanical strength. Furthermore, when the protective layers 6 are made of a ceramic material, the laminate 13 and the protective layers 6 can be fired simultaneously. In FIG. 2 , the boundary between the laminate 13 and the protective layers 6 is indicated by a two-dot chain line, but the actual boundary is not clearly visible.

[0028] The thinner the protective layer 6, the smaller and larger the capacitance of the multilayer ceramic capacitor 1. The thickness of the protective layer 6 may be, for example, 5 μm to 30 μm.

[0029] The method for manufacturing a multilayer ceramic electronic component according to the present disclosure includes a first step of alternately stacking dielectric ceramic materials and internal electrode materials to form a laminate sheet, a second step of cutting the laminate sheet to form an element precursor, a third step of removing the internal electrode materials exposed at the cut surfaces of the element precursor and conductive material adhering to the dielectric ceramic materials, and a fourth step of applying a protective layer to the cut surfaces from which the conductive material has been removed. In the third step, the dielectric ceramic materials are vaporized preferentially over the internal electrode materials.

[0030] In this embodiment, in the first step of obtaining a base laminate in which the ceramic green sheets 10 on which the internal electrode layers 5 are laid are laminated together with upper and lower cover layers, a ceramic powder mixture in which additives are added to the ceramic material serving as the material for the dielectric layers 4 is wet-pulverized and mixed in a bead mill, and then a polyvinyl butyral binder, a plasticizer, and an organic solvent are added and mixed to prepare a ceramic slurry. The ceramic material is, for example, BaTiO ３ , CaTiO ３ , SrTiO ３ , BaZrO ３ etc. may also be used.

[0031] Next, the ceramic slurry is applied onto a carrier film using a sheet forming method such as a die coater method, a doctor blade coater method, or a gravure coater method to form a ceramic green sheet 10. The thickness of the ceramic green sheet 10 may be, for example, 0.5 to 10 μm. The thinner the ceramic green sheet 10, the greater the capacitance of the multilayer ceramic capacitor 1.

[0032] Next, a conductive paste that will become the internal electrode layers 5 is prepared using a powder mainly composed of a metal material such as Ni, Cu, Ag, Sn, Pt, Pd, or Au, or an alloy material containing these metal materials. Subsequently, the prepared conductive paste is printed in a band-like pattern on the ceramic green sheet 10 using a printing method such as gravure printing or screen printing.

[0033] 4 is a diagram schematically illustrating a state in which a conductive paste is printed on a ceramic green sheet 10. The ceramic green sheet 10 is also referred to as a dielectric ceramic material. The conductive paste printed on the ceramic green sheet 10 is also referred to as an internal electrode material. Hereinafter, the ceramic green sheet 10 may be referred to as a dielectric layer 4, and the conductive paste printed on the ceramic green sheet 10 may be referred to as an internal electrode layer 5.

[0034] As long as the characteristics as a capacitor can be ensured, the thinner the thickness of the internal electrode layers 5, the more likely it is to improve the reliability of the multilayer ceramic capacitor 1. When the multilayer ceramic capacitor 1 is a capacitor with a large number of layers, the thickness T of the internal electrode layers 5 may be, for example, 0.4 μm to 1.0 μm.

[0035] Next, as shown in FIG. 5 , a predetermined number of ceramic green sheets 10 with printed internal electrode layers 5 are stacked on top of a predetermined number of ceramic green sheets 10, each being offset by a predetermined distance, and finally a predetermined number of ceramic green sheets 10 are stacked. The predetermined distance may be half the width of each internal electrode layer 5 constituting the strip-shaped electrode pattern (see FIG. 4 ). FIG. 5 is an external view schematically showing a state in which multiple ceramic green sheets 10 with printed internal electrode layers 5 are stacked. Although not shown in FIG. 5 , the ceramic green sheets 10 are stacked on a support sheet 15 (see FIG. 6 ). The support sheet 15 can be an adhesive / release sheet that can be adhered and released, such as a weak adhesive sheet or a foam release sheet.

[0036] Next, the laminate of the plurality of ceramic green sheets 10 is pressed in the stacking direction to obtain a base laminate 11 in which the plurality of ceramic green sheets 10 are integrated, as shown in Fig. 6. The base laminate 11 is also called a laminate sheet. The base laminate 11 can be pressed using, for example, an isostatic press. In Fig. 6, imaginary parting lines 12 are indicated by two-dot chain lines on the surface of the base laminate 11.

[0037] Each laminate separated by the imaginary dividing lines 12 corresponds to the laminate 13 shown in Fig. 3. The main surface 7, end surface 8, and cut surface 9 of the base laminate 11 correspond to the main surface 7, end surface 8, and cut surface 9 of the laminate 13, respectively. As shown in Fig. 6, a support sheet 15 used when stacking the ceramic green sheets 10 is located on one side of the main surface 7 of the base laminate 11.

[0038] In the second step of cutting the base laminate 11 to obtain individual element precursors 13, the base laminate 11 is cut along imaginary parting lines 12 to produce a plurality of laminates 13 as shown in FIG. 7 . Hereinafter, the element precursor 13 before firing may be referred to as a laminate 13. The base laminate 11 can be cut using, for example, a dicing saw, a push-cutting cutter, or the like. The end faces 8 and cut surfaces 9 of the laminates 13 may be the cut surfaces of the base laminate 11.

[0039] The internal electrode layers 5 are exposed on the cut surface 9 of the laminate 13. The internal electrode layers 5, which are alternately stacked with the dielectric layers 4 sandwiched therebetween, are exposed on the end surface 8 of the laminate 13, separated by polarity. In the second step, as shown in Fig. 8 , the laminate 13 may be rotated 90° on the support sheet 15 about an axis perpendicular to the end surface 8, so that one of the cut surfaces 9 becomes an open surface. For example, the rotation may be performed by rotating the laminate 13 on an alignment jig using the magnetic force of an externally applied magnetic field, or by rotating the laminate 13 by sandwiching the element precursor 13 of Fig. 7 between two elastic plates and sliding the two elastic plates in opposite directions.

[0040] The cut surface 9 of the laminate 13 is coated with debris and metallic foreign matter in the cutting chips that are generated when the base laminate 11 is cut. The metallic foreign matter may cause short circuits between the internal electrode layers 5 of opposite polarity, so in order to manufacture a highly reliable multilayer ceramic capacitor 1, it is necessary to remove these foreign matters.

[0041] In the third step of removing the conductive material adhering to the internal electrode layers 5 and the dielectric layers 4 exposed from the cut surface 9 of the laminate 13, the dielectric layers 4 are preferentially vaporized. This is based on the finding that, as shown in FIGS. 9 and 10 , the internal electrode layers 5 are preferentially vaporized in the low output range of the ultraviolet (UV) laser (see FIG. 9 ), but the dielectric layers 4 are preferentially vaporized in the high output range of the ultraviolet laser (see FIG. 10 ).

[0042] In this embodiment, sagging of the exposed portions of the internal electrode layers 5 exposed on the cut surfaces 9 of the element precursor 13 is removed by etching. Thereafter, foreign matter such as re-solidified metal vapor remaining on the dielectric layers 4 due to the etching is removed by irradiating the cut surfaces 9 of the element precursor 13 with laser light 14 to preferentially vaporize the dielectric layers 4. This makes it possible to vaporize foreign matter such as re-solidified metal vapor adhering to the dielectric layers 4 without excessively offsetting the internal electrode layers 5.

[0043] The etching method may be, for example, chemical etching or etching by laser light 14. In the case of chemical etching, it can be performed by immersing the cut surface 9 where the internal electrode layers 5 of the element precursor 13 are exposed in a solution that dissolves the internal electrode layers 5, such as an acid aqueous solution or an alkaline aqueous solution, for 5 to 30 seconds at a temperature of room temperature to 100° C. or less. In the case of etching by laser light 14, an ultraviolet laser can be used, and it can be performed with low energy, for example, by irradiating with energy of about 0.1 μJ.

[0044] In the case of chemical etching, cleaning with pure water is required to remove acid or alkali, but the laminate 13 before firing cannot be exposed to water for a long time. Therefore, the surface of the laminate 13 does not become clean, and there is a risk that it may become contaminated with internal metals (metals or alloys constituting the internal electrode layers 5). In the case of etching with laser light 14, there is a risk of contamination due to re-solidification of evaporated metal vapor on the dielectric layer 4, but simply continuing to irradiate the laser light 14 only preferentially removes the internal electrode layers 5 and does not clean the surface of the laminate 13.

[0045] In the first embodiment, the dielectric layer 4 is preferentially vaporized and removed, so that debris on the cut surface 9 can be removed without excessively offsetting the internal electrode layers 5. Since the dielectric layer 4 is covered with dielectric vapor during laser cleaning, metal vapor (vapor of the metal or alloy that constitutes the internal electrode layers 5) is less likely to penetrate. Therefore, conductive substances that may adhere to the dielectric layer 4 can be removed.

[0046] In the second embodiment, sagging of the exposed portion of the internal electrode layer 5 exposed on the cut surface 9 of the element precursor 13 is removed by etching through irradiation with a low-power laser beam 14, and then the dielectric layer 4 is irradiated with a high-power laser beam 14 to vaporize and remove foreign matter such as re-solidified metal together with the dielectric layer 4. That is, in the second embodiment, by utilizing a threshold value that divides an energy range in which the internal electrode layer 5 is preferentially vaporized from an energy range in which the dielectric layer 4 is preferentially vaporized in an ultraviolet laser, the target to be vaporized and removed can be changed simply by changing the output of the laser beam 14, and the cut surface 9 can be cleaned in one go.

[0047] In order to remove foreign matter on the cut surface 9, the internal electrode layer 5 exposed on the cut surface 9 is irradiated with a low-power laser beam 14 from a direction perpendicular to the internal electrode layer 5. This irradiation vaporizes and removes the internal electrode layer 5. As a result, the metal constituting the vaporized internal electrode layer 5 scatters or re-solidifies due to vaporization and adheres to the dielectric layer 4, but by irradiating the cut surface 9 with a high-power laser beam 14, the metal and foreign matter adhering to the dielectric layer 4 are vaporized and removed together with the dielectric layer 4, so that the cut surface 9 can be purified.

[0048] In this embodiment, the laser beam 14 is irradiated from a direction perpendicular to the cut surface 9, but the laser beam 14 may be irradiated from a direction inclined with respect to the cut surface 9. Furthermore, the element precursor 13 and the laser beam 14 may be moved relatively to each other, and the laser beam 14 may be irradiated so as to scan the cut surfaces 9 of a plurality of element precursors 13. In this embodiment, depending on the level of energy of the laser beam 14, the internal electrode layers 5 or the dielectric layers 4 can be preferentially vaporized.

[0049] In this embodiment, when the cut surface 9 of the element precursor 13 was irradiated with the laser beam 14 of the ultraviolet pulse laser at an irradiation energy of 0.13 μJ, the internal electrode layer 5 of the cut surface 9 was recessed by 0.16 μm from the dielectric layer 4, and the internal electrode layer 5 was preferentially vaporized. When the cut surface 9 of the element precursor 13 was irradiated with the laser beam 14 of the ultraviolet pulse laser at an irradiation energy of 0.75 μJ, the dielectric layer 4 of the cut surface 9 was recessed by 0.17 μm from the internal electrode layer 5. This indicates that the internal electrode layer 5 was preferentially vaporized at an irradiation energy of 0.13 μJ, and the dielectric layer 4 was preferentially vaporized at an irradiation energy of 0.75 μJ.

[0050] In this embodiment, when the protective layer 6 was attached to the cut surface 9 of the element precursor 13 obtained by cutting the base laminate 11 and dividing it into individual pieces without cleaning, the insulation defect rate was 66%, when the cut surface 9 was irradiated with a 0.13 μJ laser beam 14, the insulation defect rate was 35%, and when the cut surface 9 was irradiated with a 0.75 μJ laser beam 14, the insulation defect rate was 16%. By combining the low-power laser beam 14 and the high-power laser beam 14, the insulation defect rate was reduced and the cut surface 9 was cleaned.

[0051] In another embodiment, one laser may be used to irradiate at low power to preferentially vaporize the sagging of the internal electrode layer 5, and then the irradiation energy may be switched to irradiate at high power to preferentially vaporize the dielectric layer 4. Alternatively, two lasers, one with low power and one with high power, may be used to irradiate the element precursor 13 with the low-power laser light 14 and then with the high-power laser light 14.

[0052] In this embodiment, the laser light 14 used for irradiation may be laser light emitted from a harmonic laser of a YAG (yttrium-aluminum-garnet) laser, a green laser, or a UV laser, or may be laser light emitted from a gas laser, such as an excimer laser or a carbon dioxide laser. The spot diameter of the laser light 14 is not particularly limited, but may be about several tens of μm. Furthermore, when the element precursor 13 is irradiated with the laser light 14, vapor containing foreign matter and vapor such as the internal electrode layers 5 that have been rapidly heated and evaporated by the laser light 14 may be sucked in from the direction of its movement, i.e., from a direction including a vector perpendicular to the cut surface 9.

[0053] After removing foreign matter from the first cut surface 9A of the laminate 13, foreign matter is removed from the second cut surface 9B. To make the second cut surface 9B an open surface, a support sheet other than the support sheet 15 that secures the laminate 13 may be used. This separate support sheet may be an adhesive sheet that peels off at a higher temperature than the support sheet 15. This separate support sheet is attached to the first cut surface 9A, which is the open surface after the foreign matter has been removed, and then heated to peel off the support sheet 15. In the laminate 13 in which the first cut surface 9A is supported by the separate support sheet, the second cut surface 9B becomes the open surface.

[0054] The removal of foreign matter from the second cut surface 9B can be performed in the same manner as the removal of foreign matter from the first cut surface 9A.

[0055] The fourth step of attaching the protective layer 6 to the cut surface 9 of the element precursor 13 is performed by forming a ceramic green sheet 10 that will become the protective layer 6 on the cut surface 9 from which foreign matter has been removed. FIGS. 11A to 11C are views illustrating the step of attaching the ceramic green sheet 10 that will become the protective layer 6 to the first cut surface 9A of the laminate 13 (the lower surface of the laminate 13 in FIG. 11A ). The attachment of the protective layers 6A and 6B may be performed after removing foreign matter from the first cut surface 9A and the second cut surface 9B. Alternatively, the removal of foreign matter from the first cut surface 9A and the attachment of the protective layer 6A to the first cut surface 9A may be performed, followed by the removal of foreign matter from the second cut surface 9B and the attachment of the protective layer 6B to the second cut surface 9B.

[0056] FIG. 11A shows a state in which the second cut surface 9B of the laminate 13 (the upper surface of the laminate 13 in FIG. 11A) is fixed to a base 20 via an adhesive and peelable support sheet 15.

[0057] 11B shows a state in which the laminate 13 is pressed against the ceramic green sheet 10 on the resin sheet 21. In the state shown in Fig. 11B, the ceramic green sheet 10 is attached to the cut surface 9, but to increase the adhesive strength of the ceramic green sheet 10, the ceramic green sheet 10 that will become the protective layer 6 may be made adhesive, or the ceramic green sheet 10 that will become the protective layer 6 may be heated when being pressed against the laminate 13. Alternatively, an adhesive medium material that does not affect the final product may be used.

[0058] The ceramic green sheet 10 to be the protective layer 6 may be a single-layer ceramic green sheet 10. The ceramic green sheet 10 to be the protective layer 6 may be a multi-layer ceramic green sheet 10, and in this case, the multi-layer ceramic green sheets 10 may have different components from each other.

[0059] 11C shows a state in which the base 20 is pulled up with the ceramic green sheet 10 attached to the first cut surface 9A of the laminate 13. The surface of the ceramic green sheet 10 that is not in contact with the laminate 13 remains on the resin sheet 21, so that the ceramic green sheet 10 that will become the protective layer 6 can be formed on the first cut surface 9A of the laminate 13. The ceramic green sheet 10 may have low breaking strength.

[0060] 11A to 11C show an example in which the ceramic green sheets 10 that will become the protective layers 6 are formed on each of the first cut surface 9A and the second cut surface 9B, but the ceramic green sheets 10 that will become the protective layers 6 may be simultaneously formed on both the first cut surface 9A and the second cut surface 9B. Also, in FIGS. 11A to 11C, the ceramic green sheets 10 are attached to the lower surface of the laminate 13 from below, but it is also possible to invert each of FIGS. 11A, 11B, and 11C.

[0061] In other words, the ceramic green sheet 10 that will become the protective layer 6 may be pressed from above onto the upper surface of the laminate 13 that is fixed on the base 20 via the support sheet 15, thereby forming the ceramic green sheet 10 that will become the protective layer 6.

[0062] After or during the formation of the ceramic green sheets 10 that will become the protective layers 6 on both cut surfaces 9, the laminate 13 with the ceramic green sheets 10 that will become the protective layers 6 attached to the cut surfaces 9 may be pressed to firmly adhere the ceramic green sheets 10 that will become the protective layers 6. The perspective view of Fig. 12 shows the laminate 13 with the ceramic green sheets 10 that will become the protective layers 6 formed on the first cut surface 9A and the second cut surface 9B, at the same stage as the base part 2 before firing.

[0063] The laminate 13 on which the ceramic green sheet 10 that will become the protective layer 6 is formed is degreased in a nitrogen atmosphere and then fired in a hydrogen or nitrogen mixed atmosphere to produce the element component 2 shown in Fig. 2. After the element component 2 is produced, external electrodes 3 are formed to produce the multilayer ceramic capacitor 1 shown in Fig. 1. The external electrodes 3 can be formed, for example, by applying and baking a conductive paste that will become a base layer to the element component 2, and then forming a plated outer layer.

[0064] The protective layer 6 may be formed by adhering a ceramic green sheet 10 to the cut surface 9, or by applying a ceramic slurry to the cut surface 9 and drying it.

[0065] The method for manufacturing a multilayer electronic component according to the present disclosure is not limited to the manufacture of multilayer ceramic capacitors, but can also be applied to the manufacture of multilayer piezoelectric elements, multilayer thermistor elements, multilayer chip coils, ceramic multilayer substrates, and the like.

[0066] According to the method for manufacturing a multilayer ceramic electronic component of the present disclosure, the dielectric ceramic material is vaporized preferentially relative to the internal electrode material, thereby reducing adhesion of evaporated metal from the internal electrode material to the cut surface, and a protective layer can be formed in a state where the conductive material adhering to the cut surface has been removed, thereby making it possible to manufacture a multilayer ceramic capacitor 1 with excellent reliability.

[0067] The present disclosure can be implemented in the following configurations (1) to (4).

[0068] (1) A method for manufacturing a multilayer ceramic electronic component, comprising: a first step of alternately stacking dielectric ceramic materials and internal electrode materials to form a laminate sheet; a second step of cutting the laminate sheet to form a laminate; a third step of removing the internal electrode materials exposed at the cut surfaces of the laminate and conductive material adhering to the dielectric ceramic materials; and a fourth step of applying a protective layer to the cut surfaces from which the conductive material has been removed, wherein in the third step, the dielectric ceramic materials are vaporized preferentially over the internal electrode materials.

[0069] (2) The method for producing a multilayer ceramic electronic component according to the above configuration (1), wherein the dielectric ceramic material is vaporized by irradiation with laser light from an ultraviolet pulse laser.

[0070] (3) The method for producing a multilayer ceramic electronic component according to the above configuration (1) or (2), wherein the third step includes an etching removal treatment for selectively etching away the internal electrode material exposed from the cut surface before vaporizing the dielectric ceramic material preferentially over the internal electrode material.

[0071] (4) The method for producing a multilayer ceramic electronic component according to the above configuration (3), wherein the etching removal treatment includes irradiation with laser light or chemical etching.

[0072] Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the above-described embodiments, and various modifications and improvements are possible within the scope of the gist of the present disclosure. It goes without saying that all or part of the components constituting each of the above-described embodiments can be combined as appropriate within the scope of not contradicting each other.

[0073] REFERENCE SIGNS LIST 1 Multilayer ceramic capacitor 2 Element component 3 External electrode 3A First external electrode 3B Second external electrode 4 Dielectric layer 5 Internal electrode layer 51 End 6 Dielectric protective layer (protective layer) 7 Main surface 7A First surface 7B Second surface 8 End surface 8A First end surface 8B Second end surface 9 Cut surface 9A First cut surface 9B Second cut surface 10 Ceramic green sheet 11 Base laminate 12 Virtual parting line 13 Laminate (element precursor) 14 Laser light 18 Support sheet 20 Base 21 Resin sheet

Claims

1. A method for manufacturing a multilayer ceramic electronic component, comprising: a first step of alternately stacking dielectric ceramic material and internal electrode material to form a laminate sheet; a second step of cutting the laminate sheet to form a laminate; a third step of removing the internal electrode material exposed at the cut surface of the laminate and conductive material adhering to the dielectric ceramic material; and a fourth step of applying a protective layer to the cut surface from which the conductive material has been removed, wherein in the third step, the dielectric ceramic material is vaporized preferentially over the internal electrode material.

2. The method for producing a multilayer ceramic electronic component according to claim 1, wherein the dielectric ceramic material is vaporized by irradiation with laser light from an ultraviolet pulse laser.

3. A method for manufacturing a multilayer ceramic electronic component according to claim 1 or 2, wherein the third step includes an etching removal treatment for selectively etching away the internal electrode material exposed from the cut surface before preferentially vaporizing the dielectric ceramic material relative to the internal electrode material.

4. The method for producing a multilayer ceramic electronic component according to claim 3, wherein the etching removal treatment includes irradiation with laser light or chemical etching.

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