Method for manufacturing multilayer ceramic electronic component

Abstract

This method for manufacturing a multilayer ceramic electronic component includes: a step of obtaining a mother laminate in which a ceramic green sheet on which an internal electrode layer is laid is laminated together with upper and lower cover layers; a step of obtaining an element precursor obtained by cutting the mother laminate into individual pieces; a step of irradiating the cut side surface where the internal electrode layer of the element precursor is exposed with a laser beam, forming an air flow only by the old negative part in an opening of a suction case whose tip narrows from a direction perpendicular or inclined with respect to the cut side surface, and sucking air around the cut side surface; and a step of sticking a protective layer on the cut side surface of the element precursor.

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 conventional multilayer ceramic electronic component is described in, for example, Japanese Patent Application Laid-Open No. 2003-222999.

[0003] Japanese Patent Application Laid-Open No. 2021-057438

[0004] A method for manufacturing a multilayer ceramic electronic component according to the present disclosure includes the steps of obtaining a base laminate by stacking ceramic green sheets, on which internal electrodes are provided, together with upper and lower cover layers; cutting the base laminate to obtain individual element precursors; irradiating the cut side surfaces of the element precursors, on which the internal electrodes are exposed, with laser light while sucking air around the cut side surfaces from a direction perpendicular to or inclined to the cut side surfaces; and attaching a protective layer to the cut side surfaces of the element precursors.

[0005] 7 is a perspective view 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. 8 is a perspective view showing an element component of the multilayer ceramic capacitor; FIG. 9 is a perspective view showing a precursor of the element component; FIG. 10 is a schematic view showing a state in which a conductive paste is printed on a ceramic green sheet; FIG. 11 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. 11 is a perspective view showing a laminate divided by an imaginary dividing line; FIG. 12 is a perspective view showing a plurality of laminates cut along an imaginary dividing line; FIG. 13 is a perspective view showing the laminate of FIG. 7 rotated so that one of the side surfaces is open; FIG. 14 is a schematic view showing a laser beam irradiated from a perpendicular direction to the cut side surface while suction is performed from an oblique direction; FIG. 15 is a schematic view showing a laser beam irradiation and suction performed from a direction perpendicular to the cut side surface; FIG. 16 is a schematic view showing a laser beam irradiated from a perpendicular direction to the cut side surface while suction is performed from a vertical direction and a laser beam irradiated from an oblique direction; FIG. 17 is a schematic view showing a laser beam irradiated from a vertical direction to one cut side surface while suction is performed from a vertical direction. 9 is a schematic diagram showing suction from a vertical direction while irradiating two cut side surfaces with laser light from the vertical direction. FIG. 9 is a schematic diagram showing suction from an inclined direction while irradiating two cut side surfaces with laser light from the vertical direction. FIG. 9 is a schematic diagram showing suction from a vertical direction and suction from an inclined direction on four cut side surfaces. FIG. 9 is a schematic diagram showing that the movement direction of the laser light and the suction direction are perpendicular to each other. FIG. 9 is a schematic diagram showing suction by a swirling flow in a suction unit. FIG. 9 is a schematic diagram showing suction by a swirling flow in a suction unit. FIG. 9 is a schematic diagram showing the method of FIG. 9 when performed upside down. FIG. 9 is a diagram showing a step of attaching a protective layer to the side surface of a laminate. FIG. 9 is a diagram showing a step of attaching a protective layer to the side surface of a laminate. FIG. 9 is a diagram showing a step of attaching a protective layer to the side surface of a laminate. FIG. 9 is a perspective view showing a laminate on which a protective layer has been formed.

[0006] Multilayer ceramic capacitors are important electronic components, and in the manufacturing process, the base laminate is cut to create a laminated chip with the internal electrodes exposed on the cut side, and then a protective layer is formed on this cut side afterwards.

[0007] When cutting the base laminate, foreign matter such as debris may adhere to the cut side surface. In Patent Document 1, in order to remove the foreign matter, an air current is passed along the side surface, and the more downstream the laminate, the later the laser light is irradiated, thereby removing the foreign matter adhering to the side surface of the laminate.

[0008] When the internal electrode is rapidly heated by the laser light irradiation, the foreign matter that evaporates scatters in all directions, and some of the foreign matter is scattered upstream of the airflow, creating the problem that the foreign matter adhering to the cut side surface cannot be completely removed.

[0009] Therefore, there is a need for a method for manufacturing a multilayer ceramic electronic component that does not leave foreign matter such as debris on the cut side surfaces when cleaning the cut side surfaces by irradiating them with laser light.

[0010] The present disclosure will be described below with reference to the drawings. The drawings used in the following description are schematic, and the dimensional ratios and the like in the drawings do not necessarily correspond to those in reality. In the multilayer ceramic electronic component according to the embodiment, either direction may be defined as up or down, but in this specification, for convenience, a Cartesian coordinate system x, y, z is defined in some of the drawings.

[0011] 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. The direction perpendicular to the cut side surface 9 may also be referred to as the normal direction.

[0012] 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.

[0013] 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 before firing. The element component 2 after firing has shrunk due to firing, but 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 before firing.

[0014] 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, 6B. As shown in FIG. 1 , the multilayer ceramic capacitor 1 may also include first and second external electrodes 3A, 3B for electrical connection to the outside. As shown in FIG. 2 , the laminate 13 and the dielectric protection layers 6A, 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, 6B are also referred to as protection layers 6.

[0015] As shown in Fig. 3, the laminate 13 is formed by alternately stacking dielectric layers 4 and internal electrode layers 5 in a third direction (Z-axis direction). The laminate 13 has 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 side surface 9A and a second cut side surface 9B that face each other in a second direction (Y-axis direction).

[0016] The first external electrode 3A and the second external electrode 3B may be collectively referred to as the external electrodes 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 side surface 9A and the second cut side surface 9B may be collectively referred to as the cut side surface 9.

[0017] 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 It may be made of a ceramic material such as barium zirconate.

[0018] 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.

[0019] 3, the internal electrode layers 5 are exposed on a first cut side surface 9A and a second cut side surface 9B. The internal electrode layers 5 have end portions 51 exposed on the cut side 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.

[0020] 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.

[0021] The protective layer 6 is made of an insulating material, such as BaTiO ３ , CaTiO ３ , SrTiO ３ , BaZrO ３ The protective layer 6 may be made of the same ceramic material as the ceramic material that forms the dielectric layer 4.

[0022] One dielectric protection layer 6A is located on the first cut side surface 9A and covers the internal electrode layer 5 exposed at the first cut side surface 9A. The other dielectric protection layer 6B is located on the second cut side surface 9B and covers the internal electrode layer 5 exposed at the second cut side surface 9B.

[0023] 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.

[0024] The second external electrode 3B is located on the second end surface 8B and is electrically connected to the internal electrode layer 5 exposed at the second end surface 8B. The external electrode 3 wraps around to the first surface 7A and the second surface 7B.

[0025] The first external electrode 3A wraps around onto the first cut side surface 9A and the second cut side surface 9B, covering a portion of the dielectric protection layer 6A closer to the first end surface 8A. The second external electrode 3B wraps around onto the first cut side surface 9A and the second cut side surface 9B, covering a portion of the dielectric protection layer 6B closer to the second end surface 8B. The first external electrode 3A and the second external electrode 3B are electrically insulated from each other.

[0026] The external electrodes 3 may be composed of an underlayer that connects to the element component 2 and a plated outer layer that facilitates solder mounting. The underlayer may be applied and baked onto the element component 2 after firing, or may be applied to the element component 2 before firing and fired simultaneously with the element component 2.

[0027] 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 underlayer and the plated outer layer may have a conductive resin layer as an intermediate layer or outer layer.

[0028] On the cut side surface 9 of the laminate 13, the positive internal electrode layer 5 and the negative internal electrode layer 5 are adjacent to each other with the dielectric layer 4 sandwiched therebetween.

[0029] In this embodiment, a protective layer 6 for electrical insulation between the internal electrode layers 5 of opposite polarity and for physical protection of the end portion 51 is located on the first cut side surface 9A and the second cut side surface 9B. The protective layer 6 may be made of a ceramic material, in which case the protective layer 6 can have insulating properties and relatively high mechanical strength. Furthermore, when the protective layer 6 is made of a ceramic material, the laminate 13 and the protective layer 6 can be fired simultaneously. In FIG. 2 , the boundary between the laminate 13 and the protective layer 6 is indicated by a two-dot chain line, but the actual boundary is not clearly visible.

[0030] 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 40 μm. Next, a method for manufacturing the multilayer ceramic capacitor 1 of the present disclosure will be described.

[0031] In this embodiment, in the process of obtaining the base laminate 11 by laminating the ceramic green sheets 10 on which the internal electrode layers 5 are laid together with upper and lower cover layers, first, a ceramic powder mixture obtained by adding additives 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.

[0032] Next, the ceramic slurry is applied onto a carrier film using a sheet forming method such as a die coater, doctor blade coater, or gravure coater 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.

[0033] 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.

[0034] 4 is a diagram schematically illustrating a state in which a conductive paste is printed on a ceramic green sheet 10. 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.

[0035] 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.

[0036] Next, as shown in FIG. 5 , a predetermined number of ceramic green sheets 10 each having an internal electrode layer 5 printed thereon are stacked on top of a predetermined number of ceramic green sheets 10, each stacked at a predetermined distance. 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 illustrating a state in which a plurality of ceramic green sheets 10 each having an internal electrode layer 5 printed thereon are stacked. Although not shown in FIG. 4 , the ceramic green sheets 10 are stacked on a support sheet 18 (see FIG. 6 ). The support sheet 18 may be a weak adhesive sheet or a foam release sheet, which can be adhered and released.

[0037] 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 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.

[0038] 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 side surface 9 of the base laminate 11 correspond to the main surface 7, end surface 8, and cut side surface 9 of the laminate 13, respectively. As shown in Fig. 6, a support sheet 18 used when stacking the ceramic green sheets 10 is located on one side of the main surface 7 of the base laminate 11.

[0039] In this embodiment, in the step of cutting the base laminate 11 to obtain the 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 precursors 13 before firing may be referred to as laminates 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 side faces 9 of the laminates 13 may be the cut side faces of the base laminate 11.

[0040] The internal electrode layers 5 are exposed on the cut side surfaces 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 surfaces 8 of the laminate 13, separated by polarity.

[0041] In this embodiment, the cut side surfaces 9 of the element precursor 13 where the internal electrode layers 5 are exposed are scanned and irradiated with laser light 14, and an airflow is formed on the cut side surfaces 9 by suction using a suction unit 15 having a tapered suction port 16 from a direction perpendicular or inclined to the cut side surfaces 9 of the element precursor 13, and foreign matter generated by the irradiation of the laser light is removed by the airflow by rolling and aligning the precursors of the cut element components, and as shown in FIG. 8 , the laminate 13 is rotated 90° on a support sheet 18 around an axis perpendicular to the end surface 8, so that one of the cut side surfaces 9 is made an open surface.

[0042] In other words, the plurality of laminates 13 are rotated so that one of the cut sides 9 faces the support sheet 18. The laminates 13 may be rotated, for example, on an alignment jig by the magnetic force of an externally applied magnetic field. In addition to rotation by magnetic force, the laminates 13 may also be rotated, for example, by sandwiching the precursor element 13 shown in FIG. 7 between two elastic plates and sliding the two elastic plates in opposite directions to rotate the laminates 13.

[0043] Foreign matter such as debris generated when the base laminate 11 is cut may adhere to the cut side surfaces 9 of the laminate 13. Adjacent internal electrode layers 5 of opposite polarity are exposed on the cut side surfaces 9 of the laminate 13, and metallic foreign matter in the cutting chips adhering to the cut side surfaces 9 may cause short circuits between the internal electrode layers 5 of opposite polarity. Therefore, in order to manufacture a multilayer ceramic capacitor 1 with excellent reliability, it is necessary to remove the foreign matter on the cut side surfaces 9.

[0044] Figure 9 is a schematic diagram showing that laser light 14 is irradiated onto the cut side surface 9 from a vertical direction while being sucked in from an inclined direction, Figure 10 is a schematic diagram showing that laser light 14 is irradiated onto the cut side surface 9 from a vertical direction and that suction is performed from an inclined direction, and Figure 11 is a schematic diagram showing that the cut side surface 9 is sucked in from a vertical direction and that laser light 14 is irradiated from an inclined direction.

[0045] 9 , in order to remove foreign matter on the cut side surface 9, a laser beam 14 is irradiated onto the cut side surface 9 from a direction perpendicular to the cut side surface 9, and a suction unit 15 sucks the laser beam 14 from a direction inclined at an angle β with respect to a normal line perpendicular to the cut side surface 9 through a suction port 16, thereby sucking in vapor smoke containing foreign matter (debris) of the internal electrode layer 5 evaporated by the irradiation of the laser beam 14 and air containing vapor. This suction creates an airflow on the cut side surface 9, and the vapor smoke containing the evaporated foreign matter and air containing vapor can be forcibly sucked in and removed by the airflow. In this embodiment, the suction unit 15 has a cylindrical suction case 15a with a tapered tip, and the suction port 16 is provided at the tip of the suction case 15a, and the cross section of the suction port 16 perpendicular to the axis may be configured to be, for example, rectangular or flat oval.

[0046] By bringing suction unit 15 close to the surface of cut side surface 9 and applying suction, an air current parallel to the surface of cut side surface 9 is formed, and steam smoke 17 can be removed along with the air current. Furthermore, by making opening (sometimes referred to as suction port) 16 rectangular or flattened oval, backflow of steam smoke containing the evaporated foreign matter, steam, and air is reduced, and even when relatively large foreign matter is present, the foreign matter can be sucked through suction port 16.

[0047] The laser light 14 is irradiated by scanning a short-pulse laser beam onto the cut side surface 9, so that foreign matter adhering to the cut side surface 9 absorbs the high energy of the laser light 14 and evaporates. In this embodiment, the laser light source of the laser light 14 may be a YAG laser, a harmonic laser of a YAG laser such as a green laser or a UV laser, or a gas laser such as an excimer laser or a carbon dioxide laser. The output of the laser light 14 is not particularly limited, but may be 1 to 20 W. The spot diameter of the laser light 14 is not particularly limited, but may be 30 to 200 μm.

[0048] The vapor smoke containing foreign matter and vapor from the internal electrode layer 5 and other such materials that have been rapidly heated and evaporated by the laser light 14 moves along a path having a vector perpendicular to the cut side surface 9. Therefore, by sucking air from a direction including this vector, the vapor smoke containing foreign matter and vapor can be more effectively removed, and the re-solidification and adhesion of the evaporated material to the cut side surface 9 can be reduced.

[0049] In this way, in the method of this embodiment, by opposing the irradiation of the laser light 14 and the suction of the suction section 15, it is possible to more effectively remove steam smoke containing foreign matter and steam, and reduce the re-solidification and adhesion of foreign matter to the cut side surface 9, and various embodiments are possible.

[0050] 9 , the laser beam 14 may be irradiated at an angle β of 0° with respect to the cut side surface 9, i.e., perpendicular to the cut side surface 9, while the suction unit 15 is positioned at an angle β of 0° or more and 60° or less with respect to the cut side surface 9, and suction may be performed. As a result, foreign matter of the evaporated internal electrode layer 5 and vapor smoke 17 are generated from the cut side surface 9 by the irradiation of the laser beam 14, and flow along a path having a vector perpendicular to the cut side surface 9, but the vapor smoke 17 is moved to the suction port 16 of the suction unit 15 by the suction force and removed therefrom. In this case, the distance between the objective lens provided in the condenser 22 of the laser beam 14 and the cut side surface 9 may be set to, for example, 200 mm.

[0051] 10, the laser beam 14 and the suction unit 15 may be positioned at an angle β of 0°, i.e., perpendicular to the cut side surface 9, and the irradiation of the laser beam 14 and the suction from the suction port 16 may be performed perpendicular to the cut side surface 9. This causes the steam smoke 17, which has a vertical vector generated by the irradiation of the laser beam 14, to coincide with the flow direction of the airflow caused by the suction force from the suction port 16, and therefore the steam smoke 17 can be efficiently removed.

[0052] 11 , the suction port 16 may be set at an angle of 0° relative to the cut side surface 9, i.e., to form a vertical airflow, and the laser beam 14 may be irradiated at an angle γ of 0° or more and 80° or less relative to the cut side surface 9. This allows a larger area of ​​the laminate 13 to be scanned by the laser beam 14, and also reduces the effect of the laser beam 14 being blocked by the steam smoke 17. In either case, the distance between the cut side surface 9 and the suction port 16 may be approximately 5 to 30 mm. In this case, in order to move the laser beam 14 and efficiently scan multiple cut side surfaces 9 within a wide area, for example, the laser beam 14 may be fixed or its movement range may be limited, while the table on which the laminate 13 is placed may be moved in accordance with the scanning speed of the laser beam 14. This allows for efficient removal of foreign matter over a wide area within the area where the steam smoke 17 can be removed by the airflow, while maintaining the irradiation angle of the laser beam 14 within a predetermined range.

[0053] In the present disclosure, the suction port 16 may be a flat nozzle with a tapered tip. A flat nozzle with a flat suction port 16 can generate a uniform and strong suction force from a flat, narrow, slit-shaped opening, and therefore can remove foreign matter more evenly than a square or round nozzle. The opening shape of the flat nozzle may be 5 to 10 mm wide and 20 to 100 mm long.

[0054] When suction port 16 is a flat nozzle, the arrangement of laser light 14 and suction unit 15 to be opposed to each other may be combined depending on the range of cut side surface 9 of laminate 13 to be irradiated at one time. For example, as shown in Fig. 12, the cut side surface 9 of one laminate 13 may be irradiated with laser light 14, and the irradiation of laser light 14 and suction port 16 may be performed in a direction perpendicular to the cut side surface 9 with a width a.

[0055] Because the suction unit 15 is a flat suction nozzle, it can uniformly and powerfully suction the steam smoke 17 on the cut side surface 9, thereby removing foreign matter evenly. When irradiating the cut side surface 9 with laser light 14 and suctioning with the suction port 16 from a direction perpendicular to the cut side surface 9, the ratio (D / H) of the distance H between the surface of the cut side surface 9 and the suction port 16 and the thickness D of the aperture of the flat nozzle is appropriately set in accordance with the laser conditions. (D / H) may be set so that 0.5<H / D<1.0. This makes it possible to maximize the efficiency of foreign matter removal, since the direction of scattering of foreign matter and steam coincides with the suction direction, even though the scanning area of ​​the laser light 14 is small.

[0056] 13, when laser light 14 is irradiated perpendicularly onto the cut side surfaces 9 of the two laminates 13 and suction is performed by suction port 16, the irradiation angle β of laser light 14 is within the range of the suction opening. This allows a unidirectional flow to be formed in the region closer to suction port 16 than boundary M, making the scanning region somewhat wider and reducing the influence of steam smoke 17 that blocks laser light 14. Furthermore, the tip of suction port 16 may have a convex shape 16a, and the angle of the cross section of the tip may be set to 10° to 60°, at which point pressure loss is minimized.

[0057] FIG. 14 is a schematic diagram showing suction from an inclined direction while irradiating two cut side surfaces 9 with laser light 14 from the vertical direction. FIG. 15 is a schematic diagram showing suction from a direction inclined by width c from the vertical direction to four cut side surfaces 9. As shown in FIG. 15, suction may be performed from the vertical direction to the cut side surfaces 9, and the cut side surfaces 9 of the four laminates 13 may be irradiated with laser light 14 at an inclination angle β of approximately 20 to 45°. This allows a unidirectional flow to be formed in the region closer to the suction port 16 than the boundary M, enlarging the scanning area of ​​the laser light 14 and relatively reducing the influence of steam smoke 17 that blocks the laser light 14.

[0058] Furthermore, if the moving speed of the laser beam 14 irradiating the cut side surface 9 is increased, the suction of the generated steam smoke 17 will be delayed, causing the steam smoke 17 to tend to stagnate on the cut side surface 9, and the laser beam 14 will be irradiated within the steam smoke 17, which may result in a decrease in irradiation efficiency. To reduce this, as shown in Figure 15, an airflow directed toward the suction port may be formed on the cut side surface 9, and the moving direction of the laser beam 14 may be widened by a width c at a right angle to the direction of the airflow.

[0059] 16 is a schematic diagram showing that the moving direction of the laser beam 14 and the moving direction of the suction port 16 are perpendicular to each other. For example, as shown in FIG. 16, the moving direction of the laser beam 14 may be set to the stacking direction of the internal electrode layers 5, and the vector direction of the horizontal component of the suction port 16 for sucking the vapor smoke 17 may be set to the longitudinal direction of the internal electrode layers 5 exposed to the cut side surface 9, thereby making the moving direction perpendicular to the moving direction of the laser beam 14. As a result, the vapor smoke 17 generated by the irradiation of the laser beam 14 is always moved perpendicular to the moving direction of the laser beam 14 by an airflow having an upward vector on the cut side surface 9, so that even if the moving speed of the laser beam 14 is increased, it is possible to avoid irradiating the laser beam 14 in the vapor smoke 17, thereby enabling high irradiation efficiency and uniform foreign matter removal.

[0060] 16, the direction of the horizontal vector component of the airflow relative to the cut side surface 9 may be set to the lamination direction of the laminate 13 exposed on the cut side surface 9. In this way, even if the internal electrodes are offset by the laser light 14, the suction airflow enters the offset groove in the internal electrode layer 5, so that the steam smoke 17 generated by the laser irradiation can be discharged from the offset groove. Also, by making the direction of the airflow parallel to the longitudinal direction of the cut surface of the laminate 13, the laminate 13 is less likely to tip over, and because it is inclined from the vertical direction, suction occurs with a vector in the direction of the steam smoke from the cut surface, enabling smooth removal of foreign matter without scattering the foreign matter.

[0061] 17 is a schematic diagram illustrating suction using a swirling airflow within the suction unit 15. According to the present disclosure, foreign matter may be removed from the cut side surface 9 by suction using a swirling airflow generated within a suction case with suction ports 16 installed directly above the side surface. By creating a swirling airflow for suction, foreign matter (debris) within the opening area can be sucked in. Furthermore, by forming the suction case 15a in a C-shape, the airflow flows over a wide area of ​​the cut side surface 9 toward the center of the suction case 15a, allowing all steam and smoke on the target surface to be collected.

[0062] In the present disclosure, the suction case 15a is tapered and has a suction port 16 at its tip. The tip of the suction port 16 may be convex toward the inside of the suction case 15a. This makes it difficult for relatively large foreign objects that fly out to the outside of the vortex due to the centrifugal force of the swirling flow of the cyclone flow to fall directly onto the cut side surface 9. The tip of the suction port 16 may also have a convex shape 16a, and the angle of the cross section of the tip may be 10° to 60°, which minimizes pressure loss.

[0063] In the present disclosure, the suction unit 15 may include a suction case 15a with a C-shaped cross section, as illustrated in FIG. 17 , a swirling flow generator 20, and a suction port 16 that opens facing the laminate 13. The opening may have a diameter of 10 mm to 50 mm. The distance between the suction port 16 and the cut side surface 9 may be 2 mm to 20 mm. The swirl flow generator 20 may be any device capable of generating a swirling flow within the suction case 15a, and is not particularly limited. For example, as illustrated in FIG. 17 , the swirl flow generator 20 may have a rotationally symmetric shape surrounding the irradiated laser beam 14, and may include an exhaust unit 21 that exhausts air from the suction port 16, with exhaust pipes 21a and 21b that exhaust air in different directions. The strength of the swirl flow may be any strength sufficient to collect the steam smoke 17, and is not particularly limited. For example, the swirl flow may be 2 to 20 m / sec on the surface of the cut side surface 9. The opening of the suction case 15a may be circular or rectangular.

[0064] By exhausting the air in the suction case 15a in different directions from the exhaust pipes 21a and 21b, the air sucked into the suction case 15a from the suction port 16 is sucked in in different directions within the suction case 15a and is sucked out while rotating, generating a swirling flow. In Fig. 17, the suction case 15a is formed by extending the wall portion 20a of the swirl flow generator 20 downward, reducing the diameter at the vertical center, and integrating it into a truncated cone shape that tapers toward the tip, but this is not limited to this. The suction port 16 is defined by a debris trap piece 16b fixed to the tip of the suction case 15a. The debris trap piece 16b is fixed to the tip of the suction case 15a and has a base portion consisting of a ring-shaped body that tapers toward the upstream side in the suction direction, i.e., downward in Fig. 17, and a cylindrical inner wall portion that extends from the inner periphery of the base toward the downstream side in the suction direction, i.e., upward in Fig. 17. An annular space is provided between the inner wall and the tip of the suction case 15a, and this space accommodates debris that falls along the inner wall surface of the suction case 15a, allowing the sucked-in debris to be collected. The distance between the suction port 16 and the cut side surface 9 is not particularly limited, but may be, for example, 2 mm to 20 mm.

[0065] FIG. 18 is a schematic diagram showing suction by a swirling flow in the suction unit 15. Also, in the present disclosure, as shown in FIG. 18, the suction unit 15 may be formed so that a suction case 15a is connected to the bottom of the swirl flow generator 20. In this embodiment, a debris trap piece 16b is fixed to the tip of the suction case 15a. The debris trap piece 16b has a base made of a ring-shaped body tapering toward the upstream side in the suction direction, i.e., downward in FIG. 18, and a ring-shaped wall portion coaxially connected to the base. An annular space is formed between the wall portion and the suction case 15a, and this space accommodates debris and other foreign matter that falls along the inner wall surface of the suction case 15a, allowing the sucked foreign matter to be collected. In this case, the convex shape 16a of the suction port 16 may also be angled at an angle of 10° to 60° at the tip, which minimizes pressure loss. This allows the volume of the suction case 15a to be increased, so that the suction force does not decrease even when the laser beam 14 is scanned over a large number of cut side surfaces 9, enabling efficient removal of foreign matter. By doing so, the foreign matter remaining on the cut side surfaces 9 is measured to be 500 μm in area on the cut side surfaces 9 when observed at 5000 times magnification using a scanning electron microscope. ２ The number of particles per particle can be 10 or less, preferably 0.

[0066] Furthermore, in the present disclosure, the process of removing the foreign matter can be performed from above the cut side surface 9 as described above, but the irradiation of the laser light 14 and the suction of the steam smoke 17 can also be performed from below the cut side surface 9.

[0067] In other words, the element precursor 13, which has been cut into individual pieces from the base laminate 11, is inverted upside down with respect to the support sheet 18 to expose the cut side surface 9 on the bottom side, and laser light 14 is irradiated onto the cut side surface 9 from below, while foreign matter generated by the irradiation of laser light 14 is removed by sucking the cut side surface 9 from below, from a direction perpendicular or inclined to the cut side surface 9, using a suction section having a convex suction port at the end of a suction case that is tapered at the tip.

[0068] Fig. 19 is a schematic diagram showing the method of Fig. 9 performed upside down. To turn the singulated element precursor upside down, the cut precursor element components are rolled and aligned, and as shown in Fig. 8, the laminate 13 is rotated 90° on the support sheet 18 about an axis perpendicular to the end face 8, leaving one of the cut side faces 9 open. After that, another support sheet (not shown) is attached to this, and the original support sheet 18 is peeled off. This exposes the cut side face 9, which is irradiated with the laser light 14, downward.

[0069] 19 , in order to remove foreign matter from the cut side surface 9, laser light 14 may be irradiated upward from below the cut side surface 9 at an angle of 0°, i.e., perpendicular to the cut side surface 9, while suction unit 15 is positioned at an angle of 0° to 60° from below the cut side surface 9 to perform suction. In this way, steam smoke 17 moves from the cut side surface 9 downwardly due to the irradiation of laser light 14, and steam smoke 17 moves to suction port 16 and is removed by the suction force from suction port 16.

[0070] In addition, foreign matter can be removed because vapor smoke 17 such as metal vapor falls below the cut side surface 9 and does not reattach to the cut side surface 9. Furthermore, although not shown, the cut side surface 9 that is open downward may be irradiated with laser light 14 and suctioned from suction port 16 from a vertical direction below the cut side surface 9, or alternatively, suction may be performed from a vertical direction below the cut side surface 9 and laser light 14 may be irradiated from the below of the cut side surface 9 at an angle of 0° or more and 80° or less.

[0071] After removing foreign matter from the first cut side surface 9A of the laminate 13, foreign matter is removed from the second cut side surface 9B. To make the second cut side surface 9B an open surface, a support sheet other than the support sheet 18 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 18. This separate support sheet is attached to the first cut side surface 9A, which is the open surface after the foreign matter has been removed, and then heated to peel off the support sheet 18. In the laminate 13 in which the first cut side surface 9A is supported by the separate support sheet, the second cut side surface 9B becomes an open surface.

[0072] The removal of foreign matter from the second cut side surface 9B can be carried out in the same manner as the removal of foreign matter from the first cut side surface 9A.

[0073] The step of attaching a protective layer to the cut side surface of the element precursor is performed by forming a ceramic green sheet 10 that will become the protective layer 6 on the cut side surface 9 from which foreign matter has been removed. Figures 20A to 20C are views showing the step of attaching the ceramic green sheet 10 that will become the protective layer 6 to the first cut side surface 9A of the laminate 13 (the lower surface of the laminate 13 in Figure 20A). Note that the attachment of the protective layer 6 may be performed after removing foreign matter from the first cut side surface 9A, and then the removal of foreign matter from the second cut side surface 9B and the attachment of the protective layer 6 may be performed.

[0074] FIG. 20A shows a state in which the second cut side surface 9B of the laminate 13 (the upper surface of the laminate 13 in FIG. 20A) is fixed to a base 24 via an adhesive and peelable support sheet 18.

[0075] 20B shows a state in which the laminate 13 is pressed against the ceramic green sheet 10 on the resin sheet 27. In the state shown in Fig. 20B, the ceramic green sheet 10 is attached to the cut side 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.

[0076] 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.

[0077] 20C shows a state in which the base 24 is pulled up with the ceramic green sheet 10 attached to the first cut side 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 27, so that the ceramic green sheet 10 that will become the protective layer 6 can be formed on the first cut side surface 9A of the laminate 13. The ceramic green sheet 10 may have low breaking strength.

[0078] 20A to 20C show an example in which the ceramic green sheet 10 that will become the protective layer 6 is formed on each of the first cut side surface 9A and the second cut side surface 9B, but the ceramic green sheet 10 that will become the protective layer 6 may be simultaneously formed on both the first cut side surface 9A and the second cut side surface 9B. Also, in FIGS. 20A to 20C, the ceramic green sheet 10 is attached to the lower surface of the laminate 13 from below, but it is also possible to invert each of FIGS. 20A, 20B, and 20C.

[0079] 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 24 via the support sheet 18, thereby forming the ceramic green sheet 10 that will become the protective layer 6.

[0080] After or during the formation of the ceramic green sheets 10 that will become the protective layers 6 on both cut side surfaces 9, the laminate 13 having the ceramic green sheets 10 that will become the protective layers 6 attached to the cut side 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. 21 shows the laminate 13 in which the ceramic green sheets 10 that will become the protective layers 6 are formed on the first cut side surface 9A and the second cut side surface 9B, and is at the same stage as the base part 2 before firing.

[0081] The laminate 13 on which the ceramic green sheets 10 that will become the protective layers 6 are 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, a conductive paste that will become the external electrodes 3 is applied to the element component 2 and baked to form the external electrodes 3, thereby producing the multilayer ceramic capacitor 1 shown in Fig. 1.

[0082] The protective layer 6 may be formed by adhering the ceramic green sheet 10 to the cut side surface 9, or by applying a ceramic slurry to the cut side surface 9 and drying it.

[0083] 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.

[0084] According to the manufacturing method of the present disclosure, foreign matter (debris) and vapor from the internal electrode that are rapidly heated and evaporated by irradiation with laser light travel along a path having a vector perpendicular to the cut side surface. By generating an airflow by suction from a direction including this vector and sucking in the foreign matter (debris) and vapor evaporated from the internal electrode, the foreign matter and vapor can be removed more effectively and the re-solidification of the foreign matter and vapor and their adhesion to the cut side surface can be reduced.

[0085] According to the method for manufacturing a multilayer ceramic electronic component of the present disclosure, foreign matter (debris) and vapor from the internal electrodes that are rapidly heated and evaporated by laser light irradiation travel along a path with a vector perpendicular to the cut side surface. By generating an airflow by sucking air through a suction port in a direction including this vector, the foreign matter (debris) and vapor evaporated from the internal electrodes are sucked in, thereby more effectively removing the foreign matter and vapor and reducing their re-solidification and adhesion to the cut side surface.

[0086] The present disclosure can be implemented in the following configurations (1) to (7).

[0087] (1) A method for manufacturing a multilayer ceramic electronic component, comprising: a step of obtaining a base laminate by laminating ceramic green sheets, on which internal electrodes are provided, together with upper and lower cover layers; a step of cutting the base laminate to obtain individual element precursors; a step of irradiating a laser beam onto the cut side surface of the element precursor where the internal electrodes are exposed, and creating an airflow only using a suction section having an opening of a suction case tapered to a tip from a direction perpendicular or inclined to the cut side surface, thereby sucking in air around the cut side surface; and a step of attaching a protective layer to the cut side surface of the element precursor.

[0088] (2) The method for producing a ceramic electronic component according to the above configuration (1), wherein the suction unit is a flat suction nozzle.

[0089] (3) A method for manufacturing a multilayer ceramic electronic component according to the above configuration (1) or (2), wherein the laser light is irradiated onto the cut side surface from a direction inclined to the cut side surface, and the airflow caused by air suction is a cyclone airflow.

[0090] (4) The method for producing a multilayer ceramic electronic component according to the above configuration (3), wherein a wind tunnel case having a C-shaped cross section and the suction port is used for the air suction, and the cyclone airflow is generated inside the wind tunnel case.

[0091] (5) The method for manufacturing a multilayer ceramic electronic component according to any one of the above configurations (1) to (4), wherein a debris trap having a cylindrical inner wall portion extending upward from the inner circumferential surface of the base portion is installed at the tip of the suction case.

[0092] (6) The method for manufacturing a multilayer ceramic electronic component according to any one of the above configurations (1) to (5), wherein the direction of a component of the airflow parallel to the cut side surface and the traveling direction of the laser light form a right angle.

[0093] (7) The method for producing a multilayer ceramic electronic component according to any one of the above configurations (1) to (6), wherein the air is sucked so that the direction of the vector component of the airflow parallel to the cut side surface is parallel to the stacking direction of the cut side surface of the element precursor.

[0094] (8) The method for manufacturing a multilayer ceramic electronic component according to any one of the above configurations (1) to (7), wherein the cut side surface faces downward, the cut side surface is irradiated with laser light from below, and the cut side surface is sucked from below.

[0095] (9) The method for manufacturing a multilayer ceramic electronic component according to any one of the above configurations (1) to (8), wherein the tip of the opening of the suction case has a convex shape with a cross-sectional angle of 10° to 60°.

[0096] 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 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 side surface 9A First cut side surface 9B Second cut side surface 10 Ceramic green sheet 11 Base laminate 12 Virtual parting line 13 Laminate (element precursor) 14 Laser light 15 Suction portion 15a Suction case 16 Opening 16a Convex portion 17 Steam smoke 18 Support sheet 19 Direction of movement of steam smoke 17 20 Swirl flow generator 20a Wall portion of swirl flow generator 20 21 Exhaust portion 21a Exhaust pipe 21b Exhaust pipe 22 Concentrator 51 End

Claims

1. A step of obtaining a mother laminate in which a ceramic green sheet with internal electrodes laid thereon is laminated together with upper and lower cover layers; a step of obtaining a body precursor by cutting the mother laminate into individual pieces; a step of irradiating a laser beam onto a cut side surface where the internal electrodes of the body precursor are exposed, and creating an air flow only with a suction part having an opening of a suction case whose tip becomes thinner from a direction perpendicular or inclined to the cut side surface, and sucking the air around the cut side surface; and a step of attaching a protective layer to the cut side surface of the body precursor. A method for manufacturing a laminated ceramic electronic component including these steps.

2. The method for manufacturing a laminated ceramic electronic component according to claim 1, wherein the suction part is a flat suction nozzle.

3. The method for manufacturing a laminated ceramic electronic component according to claim 1 or claim 2, wherein the laser beam is irradiated from a direction inclined to the cut side surface, and the air flow caused by air suction is a cyclone air flow.

4. For the suction of the air, a suction case having a cross-section in a C shape with a suction part for sucking air is used, the laser beam is irradiated from inside the suction case, and the cyclone air flow is generated inside the suction case. The method for manufacturing a laminated ceramic electronic component according to claim 3.

5. The method for manufacturing a laminated ceramic electronic component according to any one of claims 1 to 4, wherein a debris trap piece having a base part and a cylindrical inner wall part extending upward from the inner peripheral part of the base part is installed at the tip of the suction case.

6. The method for manufacturing a laminated ceramic electronic component according to any one of claims 1 to 5, wherein the direction of the component of the air flow parallel to the cut side surface and the traveling direction of the laser beam are perpendicular to each other.

7. The method for manufacturing a laminated ceramic electronic component according to any one of claims 1 to 6, wherein air is sucked so that the direction of the vector component of the air flow parallel to the cut side surface is parallel to the lamination direction of the cut side surface of the body precursor.

8. The method for manufacturing a laminated ceramic electronic component according to any one of claims 1 to 7, wherein the cut side surface is directed downward, the laser beam is irradiated onto the cut side surface from below, and the cut side surface is sucked from below.

9. The method for manufacturing a laminated ceramic electronic component according to any one of claims 1 to 8, wherein the tip of the opening of the suction case has a convex shape with an angle formed by the cross-section being 10° to 60°.

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