JP7312809B2 - Manufacturing method for multilayer ceramic electronic component - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of manufacturing a laminated ceramic electronic component to which a side margin portion is retrofitted.

Patent Document 1 discloses a technique for manufacturing a multilayer ceramic capacitor. In this technique, a laminate sheet in which ceramic sheets are laminated is cut to produce a plurality of laminates having the cut surfaces where the internal electrodes are exposed as side surfaces. Then, side margins are formed on the side surfaces of the laminate to ensure insulation around the internal electrodes.

In the technique described in Patent Literature 1, it is difficult to form side margin portions on the side surfaces of the laminate because the side surfaces of the laminate face the horizontal direction immediately after the laminate sheet is cut. For this reason, in this technique, the side surfaces of the laminate are directed upward by rolling the laminate by 90 degrees before forming the side margin portions.

JP 2012-209539 A

In the technique described in Patent Literature 1, when the laminate rolls, the ridge of the laminate functions as a support shaft serving as the rotation center of the rolling, so stress tends to concentrate on the ridge of the laminate. Therefore, in the technique of rolling the laminate, the ridges of the laminate are likely to be damaged such as chipping. As a result, the production yield of laminated ceramic capacitors is lowered.

SUMMARY OF THE INVENTION In view of the circumstances as described above, an object of the present invention is to provide a method of manufacturing a multilayer ceramic electronic component in which the ridges of a multilayer body are less likely to be damaged.

To achieve the above object, a method for manufacturing a multilayer ceramic electronic component according to one aspect of the present invention includes: a plurality of ceramic layers laminated in a uniaxial direction; a plurality of internal electrodes arranged between the plurality of ceramic layers; first and second main surfaces facing the uniaxial direction; is held by the holding member to produce a laminate.
By rolling the laminate on the holding member with the ridge as a spindle, the holding surface of the laminate held by the holding member is changed from the first main surface to the first side surface.
A side margin portion is formed on the second side surface of the laminate whose first side surface is held by the holding member.

In the laminated body having this configuration, the connection angle at the ridge connecting the first main surface and the first side surface, which functions as a support shaft serving as a rotation center for rolling, is an obtuse angle. Therefore, concentration of stress on the ridge is suppressed when the laminate rolls. Therefore, the ridges of the laminate are less likely to be damaged in the manufacturing method of the laminated ceramic electronic component.

The first and second sides may be parallel to each other.
The side margin portion may be formed by punching a ceramic sheet at the second side surface.
With this configuration, the second side surfaces of the plurality of laminated bodies after rolling can be arranged on the same plane. This makes it possible to collectively form the side margin portions on the second side surfaces of the plurality of laminates. Therefore, the manufacturing efficiency of the laminated ceramic electronic component is improved.

The obtuse angle may be smaller than 93°.
With this configuration, it is possible to minimize the change in the dimensions of the laminate due to the obtuse connection angle at the ridge. As a result, the mounting area of the multilayer ceramic electronic component can be kept small.

As described above, according to the present invention, it is possible to provide a method of manufacturing a multilayer ceramic electronic component in which the ridges of the multilayer body are less likely to be damaged.

1 is a perspective view of a laminated ceramic capacitor according to one embodiment of the present invention; FIG. FIG. 2 is a cross-sectional view of the multilayer ceramic capacitor taken along line AA' in FIG. 1; 2 is a cross-sectional view of the multilayer ceramic capacitor taken along line BB' of FIG. 1; FIG. 4 is a flow chart showing a method for manufacturing the laminated ceramic capacitor. It is a top view which shows the manufacturing process of the said laminated ceramic capacitor. It is a perspective view which shows the manufacturing process of the said laminated ceramic capacitor. It is a top view which shows the manufacturing process of the said laminated ceramic capacitor. It is a schematic diagram which shows the manufacturing process of the said laminated ceramic capacitor. It is a perspective view which shows the manufacturing process of the said laminated ceramic capacitor. It is a schematic diagram which shows the manufacturing process of the said laminated ceramic capacitor. It is a schematic diagram which shows the manufacturing process of the said laminated ceramic capacitor. It is a schematic diagram which shows the manufacturing process of the said laminated ceramic capacitor. It is a perspective view which shows the manufacturing process of the said laminated ceramic capacitor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The drawings show mutually orthogonal X, Y and Z axes where appropriate. The X-axis, Y-axis, and Z-axis are common in all drawings.

[Structure of Multilayer Ceramic Capacitor 10]
1 to 3 are diagrams showing a multilayer ceramic capacitor 10 according to one embodiment of the present invention. FIG. 1 is a perspective view of a laminated ceramic capacitor 10. FIG. FIG. 2 is a cross-sectional view of the multilayer ceramic capacitor 10 taken along line AA' in FIG. FIG. 3 is a cross-sectional view of the multilayer ceramic capacitor 10 taken along line BB' of FIG.

A laminated ceramic capacitor 10 includes a ceramic element body 11 , a first external electrode 14 and a second external electrode 15 . The outer surface of the ceramic body 11 has first and second end surfaces facing the X-axis direction, first and second side surfaces facing the Y-axis direction, and first and second main surfaces facing the Z-axis direction.

The external electrodes 14 and 15 cover the first and second end faces of the ceramic body 11 and face each other in the X-axis direction with the ceramic body 11 interposed therebetween. The external electrodes 14 and 15 extend from each end surface of the ceramic body 11 to the main surface and side surfaces. As a result, the external electrodes 14 and 15 have a U-shaped cross section parallel to the XZ plane and a cross section parallel to the XY plane.

The shape of the external electrodes 14 and 15 is not limited to that shown in FIG. For example, the external electrodes 14 and 15 may extend from the end face of the ceramic body 11 to only one main face, and have an L-shaped cross section parallel to the XZ plane. Also, the external electrodes 14 and 15 do not have to extend to any of the main surfaces and side surfaces.

The external electrodes 14 and 15 are made of a good electrical conductor. Good electrical conductors forming the external electrodes 14 and 15 include, for example, metals or alloys mainly composed of copper (Cu), nickel (Ni), tin (Sn), palladium (Pd), platinum (Pt), silver (Ag), gold (Au), and the like.

The ceramic body 11 is made of dielectric ceramics and has a laminate 16 and side margin portions 17 . The laminate 16 has first and second side surfaces S1, S2 facing the Y-axis direction and first and second main surfaces M1, M2 facing the Z-axis direction. The first and second major surfaces M1, M2 extend along the XY plane.

The laminate 16 further has first and second ridges R1, R2. The first ridge portion R1 connects the first main surface M1 and the first side surface S1 at an obtuse connection angle θ1 slightly larger than 90°. The second ridge portion R2 connects the first main surface M1 and the second side surface S2 at an acute connection angle θ2 slightly smaller than 90°. That is, the side surfaces S1 and S2 are slightly inclined with respect to the XZ plane.

Sides S1 and S2 of laminate 16 are preferably parallel to each other. Thereby, the side margin portions 17 can be efficiently formed on the side surfaces S<b>1 and S<b>2 of the laminate 16 . A method for forming the side margin portions 17 will be described in a method for manufacturing the laminated ceramic capacitor 10, which will be described later.

Also, the connection angle θ1 at the first ridge portion R1 of the laminate 16 is preferably smaller than 93°. The connection angle θ2 at the second ridge portion R2 of the laminate 16 is preferably larger than 87°. As a result, the dimension of the laminated body 16 in the Y-axis direction can be kept small, so that the mounting area of the laminated ceramic capacitor 10 can be kept small.

In the laminate 16, the ridges R1 and R2 may be ridgelines that directly connect the first main surface M1 and the side surfaces S1 and S2, but preferably rounded surfaces that gently connect the first main surface M1 and the side surfaces S1 and S2. As a result, stress is less likely to concentrate on the ridges R1 and R2 in the laminate 16, so that the ridges R1 and R2 are less likely to be damaged.

The laminate 16 has a structure in which a plurality of flat ceramic layers extending along the XY plane are laminated in the Z-axis direction. The laminate 16 has a capacitance forming portion 18 and a cover portion 19 . The cover portion 19 covers the capacitance forming portion 18 from above and below in the Z-axis direction, and constitutes main surfaces M1 and M2 of the laminate 16 .

The capacitance forming portion 18 has a plurality of sheet-like first and second internal electrodes 13 arranged between a plurality of ceramic layers and extending along the XY plane. The internal electrodes 12 and 13 are alternately arranged along the Z-axis direction. That is, the internal electrodes 12 and 13 face each other in the Z-axis direction with the ceramic layer interposed therebetween.

The first internal electrode 12 is led out only to the first end face of the ceramic body 11 , and the second internal electrode 13 is led out only to the second end face of the ceramic body 11 . Thereby, the first internal electrode 12 is connected only to the first external electrode 14 and the second internal electrode 13 is connected only to the second external electrode 15 .

The internal electrodes 12 and 13 are formed over the entire width of the capacitance forming portion 18 in the Y-axis direction and are exposed on both side surfaces S1 and S2 of the laminate 16 . The side margin portions 17 cover both side surfaces S1 and S2 of the laminate 16. As shown in FIG. Thereby, the insulation between the internal electrodes 12 and 13 on both side surfaces S1 and S2 of the laminate 16 can be ensured.

With such a configuration, in the multilayer ceramic capacitor 10, when a voltage is applied between the first external electrode 14 and the second external electrode 15, the voltage is applied to the plurality of ceramic layers between the first internal electrode 12 and the second internal electrode 13. As a result, in the multilayer ceramic capacitor 10 , electric charges corresponding to the voltage between the first external electrode 14 and the second external electrode 15 are stored.

In the ceramic body 11, dielectric ceramics with a high dielectric constant are used in order to increase the capacitance of each ceramic layer between the internal electrodes 12,13. Dielectric ceramics with a high dielectric constant include, for example, perovskite structure materials containing barium (Ba) and titanium (Ti), represented by barium titanate (BaTiO ₃ ).

The ceramic layer is _the calcium (SRTIO 3) system (SRTIO ₃ ) system, calcium titanate (CATIO 3) system, magnesium titanate (MGTIO ₃ ) system, calcium diltonate (CAZRO ₃ ) system, calcium dylconate (Zr, CA (Zr, ZR, CAZRO ₃ ) system. TI) may be configured in a zircon acid (BAZRO ₃ ) system, titanium oxide (TIO ₂ ) system, etc.

The internal electrodes 12 and 13 are made of a good electrical conductor. A typical good electrical conductor forming the internal electrodes 12 and 13 is nickel (Ni), and other metals or alloys mainly composed of copper (Cu), palladium (Pd), platinum (Pt), silver (Ag), and gold (Au).

The multilayer ceramic capacitor 10 according to the present embodiment only needs to include the laminate 16 and the side margin portions 17, and other configurations can be changed as appropriate. For example, the numbers of the first and second internal electrodes 12 and 13 can be appropriately determined according to the size and performance required of the multilayer ceramic capacitor 10 .

[Manufacturing Method of Multilayer Ceramic Capacitor 10]
FIG. 4 is a flow chart showing the manufacturing method of the multilayer ceramic capacitor 10. As shown in FIG. 5 to 13 are diagrams showing the manufacturing process of the multilayer ceramic capacitor 10. FIG. Hereinafter, a method for manufacturing the laminated ceramic capacitor 10 will be described along FIG. 4 with reference to FIGS. 5 to 13 as appropriate.

(Step S01: Ceramic sheet preparation)
In step S01, the first ceramic sheet 101 and the second ceramic sheet 102 for forming the capacitance forming portion 18, and the third ceramic sheet 103 for forming the cover portion 19 are prepared. The ceramic sheets 101, 102, 103 are configured as unfired dielectric green sheets containing dielectric ceramics as a main component.

The ceramic sheets 101, 102, 103 are formed into sheets using, for example, a roll coater or a doctor blade. The thicknesses of the ceramic sheets 101 and 102 are adjusted according to the thickness of the ceramic layers in the capacitor forming portion 18 after firing. The thickness of the third ceramic sheet 103 can be adjusted appropriately.

FIG. 5 is a plan view of the ceramic sheets 101, 102, 103. FIG. At this stage, the ceramic sheets 101, 102, 103 are constructed as large sheets that are not singulated. FIG. 5 shows cutting lines Lx and Ly used when singulating each laminated ceramic capacitor 10 . The cutting line Lx is parallel to the X-axis, and the cutting line Ly is parallel to the Y-axis.

As shown in FIG. 5, unfired first internal electrodes 112 corresponding to the first internal electrodes 12 are formed on the first ceramic sheet 101, and unfired second internal electrodes 113 corresponding to the second internal electrodes 13 are formed on the second ceramic sheet 102. No internal electrodes are formed on the third ceramic sheet 103 corresponding to the cover portion 19 .

The internal electrodes 112, 113 can be formed by applying any conductive paste to the ceramic sheets 101, 102. FIG. A method for applying the conductive paste can be arbitrarily selected from known techniques. For example, a screen printing method or a gravure printing method can be used to apply the conductive paste.

In the internal electrodes 112 and 113, gaps in the X-axis direction along the cutting line Ly are formed every other cutting line Ly. The gaps between the first internal electrodes 112 and the gaps between the second internal electrodes 113 are alternately arranged in the X-axis direction. That is, the cutting lines Ly passing through the gaps between the first internal electrodes 112 and the cutting lines Ly passing through the gaps between the second internal electrodes 113 are arranged alternately.

(Step S02: Lamination)
In step S02, ceramic sheets 101, 102, and 103 prepared in step S01 are laminated as shown in FIG. In the laminated sheet 104, the first ceramic sheets 101 and the second ceramic sheets 102 corresponding to the capacitance forming portion 18 are alternately laminated in the Z-axis direction.

In the laminated sheet 104, the third ceramic sheet 103 corresponding to the cover portion 19 is laminated on the upper and lower surfaces of the alternately laminated ceramic sheets 101 and 102 in the Z-axis direction. Although three third ceramic sheets 103 are laminated in the example shown in FIG. 6, the number of third ceramic sheets 103 can be changed as appropriate.

The laminated sheet 104 is integrated by pressing the ceramic sheets 101, 102, 103 together. For pressure bonding of the ceramic sheets 101, 102, 103, it is preferable to use, for example, hydrostatic pressurization or uniaxial pressurization. Thereby, it is possible to increase the density of the laminated sheet 104 .

(Step S03: Disconnect)
In step S03, the laminate sheet 104 obtained in step S02 is cut along cutting lines Lx and Ly to produce an unfired laminate 116. FIG. Laminate 116 corresponds to laminate 16 after firing. For cutting the laminated sheet 104, for example, a press cutting blade or a rotating blade can be used.

7 and 8 are schematic diagrams for explaining an example of step S03. FIG. 7 is a plan view of the laminated sheet 104. FIG. FIG. 8 is an end view of the laminated sheet 104 viewed from the X-axis direction. The laminated sheet 104 is cut by a press cutting blade F along cutting lines Lx and Ly while being held by a tape-shaped holding member T having adhesiveness.

As shown in FIG. 8, when cutting the laminated sheet 104 along the cutting line Lx, the push cutting blade F is inserted into the laminated sheet 104 with a slight inclination about the X axis with respect to the XZ plane. As a result, as shown in FIG. 9, an unfired laminate 116 is obtained in which the side surfaces S1 and S2 are parallel to each other and tilted with respect to the XZ plane.

In the laminate 116, the connection angle θ1 between the first main surface M1 and the first side surface S1 at the first ridge R1 and the connection angle θ2 between the first main surface M1 and the second side surface S2 at the second ridge R2 can be controlled by the inclination of the press cutting blade F with respect to the XZ plane. However, the method of controlling the connection angles θ1 and θ2 is not limited to this.

(Step S04: Side Margin Formation)
In step S04, unfired ceramic body 111 is produced by providing unfired side margin portions 117 on side surfaces S1 and S2 of laminated body 116 obtained in step S03 where internal electrodes 112 and 113 are exposed. 10 to 13 are diagrams showing the process of step S04.

FIG. 10A shows the state immediately after step S03. In this state, since the stacks 116 arranged on the holding member T in the X-axis and Y-axis directions are close to each other, it is difficult to handle each stack 116 . For this reason, the intervals between the laminates 116 arranged on the holding member T in the X-axis and Y-axis directions are widened.

Specifically, the holding member T shown in FIG. 10A is stretched in the X-axis and Y-axis directions. As a result, the gap between the laminates 116 on the holding member T is widened as shown in FIG. 10B. In addition, if necessary, such as when the holding member T used in step S03 does not have stretchability, the laminate 116 is replaced with another holding member T having stretchability in advance.

Even in the state shown in FIG. 10B, since the side surfaces S1 and S2 of each laminate 116 face the Y-axis direction, which is the in-plane direction of the surface of the holding member T, it is difficult to provide the side margin portions 117 on the side surfaces S1 and S2 of the laminate 116. Therefore, the orientation of the laminate 116 on the holding member T is changed.

Specifically, as shown in FIG. 11A, a flat working plate B extending along the XY plane is arranged on the second main surface M2 of the laminate 116. As shown in FIG. The working plate B preferably covers the second main surfaces M2 of all the laminates 116 on the holding member T collectively. The action plate B is preferably made of a non-slip elastic material such as silicone rubber.

Then, as shown in FIG. 11B, the action plate B is moved in the Y-axis direction. At this time, a moment is generated in the laminate 116 by a force applied from the working plate B in the Y-axis direction. As a result, the laminated body 116 rolls on the holding member T around the first ridge portion R1 connecting the first main surface M1 and the first side surface S1.

By rolling the laminate 116, the first side surface S1 is adhered to the holding member T after the first main surface M1 is peeled off from the holding member T. As shown in FIG. As a result, as shown in FIG. 11C, the holding surface of the laminate 116 held by the holding member T is changed from the first main surface M1 to the first side surface S1, and the second side surface S2 of the laminate 116 faces upward in the Z-axis direction.

In the laminated body 116, the first ridge R1, which functions as a support shaft for rolling, has an obtuse angle, so the stress applied to the first ridge R1 during rolling is dispersed. In other words, stress is less likely to concentrate on the first ridge portion R1 of the laminated body 116 during rolling. Therefore, in step S04, when the laminated body 116 rolls, the laminated body is less likely to be damaged such as chipped.

In the state shown in FIG. 11C, the second side surfaces S2 of all the laminates 116 on the holding member T face the upper side in the Z-axis direction, which is opposite to the holding member T side. An example of a method for forming the side margin portion 117 will be described with reference to FIG. 12 .

First, as shown in FIG. 12A, a ceramic sheet 117s is arranged so as to cover the laminate 116 arranged on the holding member T. Then, as shown in FIG. At this time, since the second side surfaces S2 of all the laminates 116 are on the same plane along the XY plane, the ceramic sheet 117s can be brought into close contact with the second side surfaces S2 of all the laminates 116. FIG.

The ceramic sheet 117s is configured as an unfired dielectric green sheet, similar to the ceramic sheets 101, 102 and 103 prepared in step S01. The ceramic sheet 117s is formed into a sheet shape using, for example, a roll coater or a doctor blade.

Then, from the state shown in FIG. 12A, the ceramic sheet 117s is cut along the contour of the second side surface S2 of each laminate 116. Then, as shown in FIG. A method for cutting the ceramic sheet 117s can be arbitrarily selected from known methods.

In the punching method, the ceramic sheet 117s is pressed from above in the Z-axis direction by an elastic member. As a result, a shearing force is applied along the contour of the second side surface S2 of each laminate 116 to the ceramic sheet 117s sandwiched between the elastic member and the second side surface S2 of the laminate 116 . Thereby, the ceramic sheet 117s can be punched out.

Subsequently, by replacing the laminated body 116 shown in FIG. 12B with another holding member T, the orientation of the laminated body 116 in the Y-axis direction is reversed. Side margin portions 117 are also formed on the first side surface S1 opposite to the second side surface S of the laminate 116, where the side margin portions 117 are not formed, in the same manner as described above.

As a result, as shown in FIG. 13, an unfired ceramic body 111 having side margin portions 117 formed on both side surfaces S1 and S2 of the laminate 116 is obtained. In the unfired ceramic body 111 , the side margin portions 117 cover both side surfaces S 1 and S 2 of the laminate 116 where the internal electrodes 112 and 113 are exposed.

Note that the method of forming the side margin portion 117 on the second side surface S2 of the laminated body 116 in the state shown in FIG. 11C is not limited to the above. For example, a pre-cut ceramic sheet 117 s may be attached to the second side surface S<b>2 of the laminate 116 . Alternatively, the ceramic slurry may be applied to the second side surface S2 of the laminate 116 by, for example, a dipping method.

(Step S05: Firing)
In step S05, the ceramic body 11 of the multilayer ceramic capacitor 10 shown in FIGS. 1 to 3 is produced by firing the unfired ceramic body 111 obtained in step S04. That is, by step S<b>05 , the laminated body 116 becomes the laminated body 16 and the side margin portion 117 becomes the side margin portion 17 .

The sintering temperature in step S<b>05 can be determined based on the sintering temperature of the ceramic body 111 . For example, when a barium titanate (BaTiO ₃ )-based material is used, the firing temperature can be about 1000 to 1300°C. Also, the firing can be performed, for example, in a reducing atmosphere or in a low oxygen partial pressure atmosphere.

(Step S06: External electrode formation)
In step S06, external electrodes 14 and 15 are formed on both ends of the ceramic body 11 obtained in step S05 in the X-axis direction to fabricate the multilayer ceramic capacitor 10 shown in FIGS. A method for forming the external electrodes 14 and 15 in step S06 can be arbitrarily selected from known methods.

By the above, the multilayer ceramic capacitor 10 is completed. In this manufacturing method, since the side margin portions 17 are attached later to the side surfaces S1 and S2 of the laminate 16 where the internal electrodes 12 and 13 are exposed, the positions of the Y-axis direction ends of the plurality of internal electrodes 12 and 13 in the ceramic body 11 are aligned within a range of 0.5 μm.

[Other embodiments]
Although the embodiments of the present invention have been described above, it is needless to say that the present invention is not limited to the above-described embodiments and can be modified in various ways.

For example, in the laminates 16 and 116, if the connection angle θ1 at the first ridge portion R1 is an obtuse angle, it is possible to realize a structure that is less likely to be damaged during rolling. Therefore, in the laminates 16 and 116, the connection angle θ2 at the second ridge portion R2 may not necessarily be an acute angle, and may be a right angle or an obtuse angle.

Further, in the above embodiment, the laminated ceramic capacitor 10 was explained as an example of the laminated ceramic electronic component, but the present invention can be applied to laminated ceramic electronic components in general. Examples of such multilayer ceramic electronic components include chip varistors, chip thermistors, and multilayer inductors.

DESCRIPTION OF SYMBOLS 10... Laminated ceramic capacitors 11, 111... Ceramic element bodies 12, 112... First internal electrodes 13, 113... Second internal electrodes 14, 114... First external electrodes 15, 115... Second external electrodes 104... Laminated sheets 16, 116... Laminated bodies 17, 117... Side margin portions M1, M2... Main surfaces S1, S2... Side surfaces R1, R2... Edges θ1, θ2... Connection angle T... Holding member F … Push cutting blade B … Working plate

Claims (3)

a plurality of ceramic layers laminated in a uniaxial direction; a plurality of internal electrodes arranged between the plurality of ceramic layers; first and second main surfaces facing the uniaxial direction; Producing a laminate whose first main surface is held by a holding member,
By rolling the laminate on the holding member with the first ridge as a spindle, the holding surface of the laminate held by the holding member is changed from the first main surface to the first side surface, the second side surface of the laminate held by the holding member is opposed parallel to the ceramic sheet, and the ceramic sheet is pressed against the second side surface and punched out to form a side margin portion;
firing the laminate having the side margins formed thereon;
A method for manufacturing a multilayer ceramic electronic component. A method for manufacturing a multilayer ceramic electronic component according to claim 1,
A method of manufacturing a multilayer ceramic electronic component, wherein the first and second side surfaces are parallel to each other. A method for manufacturing a multilayer ceramic electronic component according to claim 1 or 2,
the obtuse angle is less than 93°,
wherein the acute angle is greater than 87°;
A method for manufacturing a multilayer ceramic electronic component.

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