JP6433931B2 - Multilayer ceramic electronic component manufacturing method and multilayer ceramic electronic component manufacturing apparatus - Google Patents

Description

  The present invention relates to a method for manufacturing a multilayer ceramic electronic component to which a side margin portion is retrofitted, a manufacturing apparatus therefor, a ceramic body, and a multilayer ceramic electronic component using the same.

  In recent years, with the miniaturization and high performance of electronic devices, there is an increasing demand for miniaturization and large capacity for multilayer ceramic capacitors used in electronic devices. In order to meet this demand, it is effective to secure a sufficient crossing area of the internal electrodes laminated between the ceramic layers of the multilayer ceramic capacitor.

  On the other hand, in a general method for manufacturing a multilayer ceramic capacitor, due to the accuracy of each step (for example, patterning of internal electrodes, cutting of a laminated sheet, etc.) May decrease.

  Patent Documents 1 and 2 disclose techniques for retrofitting side margin portions. That is, in this technique, by cutting the laminated sheet, a laminated chip in which the internal electrode is exposed on the side surface is produced, and a side margin portion is provided on the side surface of the laminated chip. As a result, it is possible to prevent a decrease in the crossing area of the internal electrodes due to stacking deviation or the like, and to sufficiently secure the crossing area.

JP 2012-209539 A JP2012-191163

  However, in any of the manufacturing methods of Patent Documents 1 and 2, in the step of cutting the laminated sheet, dragging by the cutting blade occurs on the cut surface, and a short circuit failure is likely to occur between the internal electrodes exposed on the cut surface.

  In view of the circumstances as described above, an object of the present invention is to provide a method for manufacturing a multilayer ceramic electronic component capable of preventing a short circuit failure between internal electrodes on the cut surface of the multilayer sheet, a manufacturing apparatus therefor, a ceramic body, It is to provide a multilayer ceramic electronic component using the same.

In order to achieve the above object, in a method for manufacturing a multilayer ceramic electronic component according to one aspect of the present invention, a multilayer sheet having ceramic sheets stacked in a uniaxial direction and internal electrodes disposed between the ceramic sheets. Is prepared.
A first surface formed at the tip end in the uniaxial direction and inclined at a first angle with respect to the uniaxial direction, and formed side by side with the first surface in the uniaxial direction, the first surface with respect to the uniaxial direction. The laminated sheet is cut using a cutting blade having a second surface that is inclined at a second angle smaller than an angle of 1, and a curved surface that smoothly connects the first surface and the second surface. Thus, a multilayer chip having a side surface from which the internal electrode is exposed is manufactured.
A side margin is provided on the side surface of the multilayer chip.
In this configuration, since the curved surface is provided between the first surface and the second surface of the cutting blade, the cutting surface (that is, the side surface) is dragged by the angle between the first surface and the second surface. Can be prevented. Therefore, it is possible to prevent a short-circuit failure between the internal electrodes due to a scratch on the cut surface.

For example, producing the laminated chip may include cutting with the cutting blade such that the value of the surface roughness Ra of the side surface is 20 nm or less.
Thereby, the incidence rate of short-circuit failure between the internal electrodes can be sufficiently reduced.

Moreover, producing the said laminated chip | tip may include cut | disconnecting using the said cutting blade by which the said 1st surface was mirror-finished.
Thereby, generation | occurrence | production of a dragging | flaw can be prevented more effectively.

The manufacturing apparatus of the multilayer ceramic electronic component which concerns on the other form of this invention comprises a table, a cutting blade, and a drive part.
The said table mounts the lamination sheet which has the ceramic sheet laminated | stacked on the uniaxial direction, and the internal electrode arrange | positioned between the said ceramic sheets.
The cutting blade is formed at a tip end portion in the uniaxial direction and inclined at a first angle with respect to the uniaxial direction, and is formed side by side with the first surface in the uniaxial direction. A second surface that is inclined at a second angle smaller than the first angle, and a curved surface that smoothly connects the first surface and the second surface, and the tip portion Is arranged to face the table in the uniaxial direction.
The drive unit holds the cutting blade and drives the cutting blade in the uniaxial direction with respect to the table.
Even in this configuration, since the cutting blade having the curved surface is provided between the first surface and the second surface, the cutting surface (that is, the side surface) is dragged by the angle between the first surface and the second surface. It can be prevented from happening. Therefore, it is possible to prevent a short-circuit failure between the internal electrodes due to a scratch on the cut surface.

An unfired ceramic body for manufacturing a multilayer ceramic electronic component according to still another embodiment of the present invention includes a multilayer chip and a side margin portion.
The multilayer chip includes laminated ceramic layers, internal electrodes disposed between the ceramic layers, and side surfaces from which the internal electrodes are exposed.
The side margin portion is provided on the side surface of the multilayer chip.
Furthermore, the value of the surface roughness Ra of the side surface of the multilayer chip is 20 nm or less.
By setting the value of the surface roughness Ra of the side surface to 20 nm or less, a short circuit failure between the internal electrodes can be sufficiently prevented.

  A multilayer ceramic electronic component according to still another embodiment of the present invention may be one using the ceramic body.

  As described above, according to the present invention, a method for manufacturing a multilayer ceramic electronic component capable of preventing a short circuit failure between internal electrodes on the cut surface of the multilayer sheet, an apparatus for manufacturing the multilayer ceramic electronic component, a ceramic body, and a method for using the same The multilayer ceramic electronic component can be provided.

1 is a perspective view of a multilayer ceramic capacitor according to an embodiment of the present invention. It is sectional drawing along the AA 'line of the said multilayer ceramic capacitor. It is sectional drawing along the BB 'line of the said multilayer ceramic capacitor. It is a flowchart which shows the manufacturing method of the said multilayer ceramic capacitor. It is a top view of the lamination sheet prepared by step S01 of the said manufacturing method. It is a perspective view of the lamination sheet which shows step S02 of the said manufacturing method. It is a top view of the lamination sheet after step S03 of the said manufacturing method. It is sectional drawing of the lamination sheet which shows step S04 of the said manufacturing method. It is sectional drawing of the laminated chip which shows step S05 of the said manufacturing method. It is a perspective view of the unfired element body after step S05 of the manufacturing method. It is a mimetic diagram of a cutting device (manufacturing device of a multilayer ceramic capacitor) concerning this embodiment. It is a side view of the cutting blade with which the said cutting device is provided. It is a side view of the cutting blade which concerns on the comparative example of this embodiment. It is sectional drawing of the lamination sheet which shows said step S03 using the cutting blade which concerns on the said comparative example. It is a graph which shows the relationship between the surface roughness of a cut surface (side surface), and IR defect rate (initial insulation resistance defect rate) of a multilayer ceramic capacitor. It is a figure which shows typically the side surface of the lamination | stacking chip | tip after said step S03 using the cutting blade which concerns on the said comparative example. It is sectional drawing of the lamination sheet which shows said step S03 using the cutting blade concerning this embodiment. It is a figure which shows typically the side surface of the lamination | stacking chip | tip after said step S03 using the cutting blade which concerns on this embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the drawing, an X axis, a Y axis, and a Z axis that are orthogonal to each other are shown as appropriate. The X axis, Y axis, and Z axis are common in all drawings.

[Configuration of Multilayer Ceramic Capacitor 10]
1 to 3 are views showing a multilayer ceramic capacitor 10 according to an embodiment of the present invention. FIG. 1 is a perspective view of a multilayer ceramic capacitor 10. 2 is a cross-sectional view of the multilayer ceramic capacitor 10 taken along the line AA ′ of FIG. FIG. 3 is a cross-sectional view of the multilayer ceramic capacitor 10 taken along the line BB ′.

  The multilayer ceramic capacitor 10 includes an element body 11, a first external electrode 14, and a second external electrode 15. The external electrodes 14 and 15 are spaced apart from each other and face each other in the X-axis direction with the element body 11 interposed therebetween.

The element body 11 has two end surfaces facing the X-axis direction, two side surfaces facing the Y-axis direction, and two main surfaces facing the Z-axis direction. The ridges connecting the surfaces of the element body 11 are chamfered. In the element body 11, for example, the dimension in the X-axis direction can be set to 1.0 mm, and the dimension in the Y-axis and Z-axis directions can be set to 0.5 mm.
The shape of the element body 11 is not limited to such a shape. For example, each surface of the element body 11 may be a curved surface, and the element body 11 may have a rounded shape as a whole.

  The external electrodes 14 and 15 cover both end surfaces of the element body 11 in the X-axis direction, and extend to both side surfaces in the Y-axis direction and both main surfaces in the Z-axis direction that are connected to both end surfaces in the X-axis direction. Thereby, in both the external electrodes 14 and 15, the shape of the cross section parallel to the XZ plane and the cross section parallel to the XY axis is U-shaped.

Each of the external electrodes 14 and 15 is formed of a good conductor and functions as a terminal of the multilayer ceramic capacitor 10. As a good conductor for forming the external electrodes 14 and 15, for example, a metal mainly composed of nickel (Ni), copper (Cu), palladium (Pd), platinum (Pt), silver (Ag), gold (Au), etc. Or alloys can be used.
The external electrodes 14 and 15 may have a single layer structure or a multilayer structure.

The external electrodes 14 and 15 having a multilayer structure may be configured, for example, as a two-layer structure of a base film and a surface film or a three-layer structure of a base film, an intermediate film, and a surface film.
The base film can be, for example, a baking film of a metal or alloy whose main component is nickel, copper, palladium, platinum, silver, gold or the like.
The intermediate film can be, for example, a plating film of a metal or alloy mainly composed of platinum, palladium, gold, copper, nickel, or the like.
The surface film can be, for example, a plating film of a metal or alloy containing copper, tin, palladium, gold, zinc, or the like as a main component.

The element body 11 includes a laminated chip 16 and a side margin portion 17.
The side margin portions 17 have a flat plate shape extending along the XZ plane and cover both side surfaces of the multilayer chip 16 in the Y-axis direction.
The multilayer chip 16 includes a capacitance forming portion 18 and a cover portion 19. The cover portion 19 has a flat plate shape extending along the XY plane, and covers both main surfaces of the capacitance forming portion 18 in the Z-axis direction.
The side margin portion 17 and the cover portion 19 mainly have a function of protecting the capacitance forming portion 18 and ensuring insulation around the capacitance forming portion 18.

  The capacitance forming unit 18 includes a plurality of first internal electrodes 12 and a plurality of second internal electrodes 13. Each of the internal electrodes 12 and 13 has a sheet shape extending along the XY plane, and is alternately arranged in the Z-axis direction. The first internal electrode 12 is connected to the first external electrode 14 and is separated from the second external electrode 15. On the contrary, the second internal electrode 13 is connected to the second external electrode 15 and is separated from the first external electrode 14.

  Each of the internal electrodes 12 and 13 is formed of a good conductor and functions as an internal electrode of the multilayer ceramic capacitor 10. As a good conductor for forming the internal electrodes 12 and 13, for example, nickel (Ni), copper (Cu), palladium (Pd), platinum (Pt), silver (Ag), gold (Au), or a metal containing these alloys Material is used.

The capacitance forming unit 18 is formed of dielectric ceramics. In the multilayer ceramic capacitor 10, a dielectric ceramic having a high dielectric constant is used as a material for forming the capacitance forming portion 18 in order to increase the capacitance of each dielectric ceramic layer between the internal electrodes 12 and 13. Examples of the dielectric ceramic having a high dielectric constant include a perovskite structure material containing barium (Ba) and titanium (Ti) typified by barium titanate (BaTiO ₃ ). In addition to the barium titanate system, the dielectric ceramic constituting the capacitance forming unit 18 is not limited to strontium titanate (SrTiO ₃ ) system, calcium titanate (CaTiO ₃ ) system, magnesium titanate (MgTiO ₃ ) system, zircon. It may be a calcium oxide (CaZrO ₃ ) system, a calcium zirconate titanate (PCZT) system, a barium zirconate (BaZrO ₃ ) system, a titanium oxide (TiO ₂ ) system, or the like.

  The side margin part 17 and the cover part 19 are also formed of dielectric ceramics. The material for forming the side margin portion 17 and the cover portion 19 may be insulating ceramics. However, by using the same material as that for the capacitance forming portion 18, the manufacturing efficiency is improved and the internal stress in the element body 11 is reduced. It is suppressed.

  With the above configuration, in the multilayer ceramic capacitor 10, when a voltage is applied between the first external electrode 14 and the second external electrode 15, a plurality of pieces between the first internal electrode 12 and the second internal electrode 13 are provided. A voltage is applied to the dielectric ceramic layer. As a result, in the multilayer ceramic capacitor 10, charges corresponding to the voltage between the first external electrode 14 and the second external electrode 15 are stored.

  The configuration of the multilayer ceramic capacitor 10 is not limited to a specific configuration, and a known configuration can be appropriately adopted according to the size and performance required for the multilayer ceramic capacitor 10. For example, the number of internal electrodes 12 and 13 in the capacitance forming unit 18 can be determined as appropriate.

[Method of Manufacturing Multilayer Ceramic Capacitor 10]
FIG. 4 is a flowchart showing a method for manufacturing the multilayer ceramic capacitor 10. 5 to 10 are diagrams illustrating a manufacturing process of the multilayer ceramic capacitor 10. Hereinafter, a method for manufacturing the multilayer ceramic capacitor 10 will be described along FIG. 4 with reference to FIGS.

(Step S01: Preparation of ceramic sheet)
In step S01, a first ceramic sheet 101 and a second ceramic sheet 102 for forming the capacitance forming portion 18 and a third ceramic sheet 103 for forming the cover portion 19 are prepared.

  FIG. 5 is a plan view of the ceramic sheets 101, 102, 103. 5A shows the ceramic sheet 101, FIG. 5B shows the ceramic sheet 102, and FIG. 5C shows the ceramic sheet 103. The ceramic sheets 101, 102, 103 are configured as unfired dielectric green sheets, and are formed into a sheet shape using, for example, a roll coater or a doctor blade.

  In the step S01, the ceramic sheets 101, 102, 103 are not cut for each multilayer ceramic capacitor 10. FIG. 5 shows cutting lines Lx and Ly when cutting each multilayer 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, an unfired first internal electrode 112 corresponding to the first internal electrode 12 is formed on the first ceramic sheet 101, and an unfired first internal electrode 112 corresponding to the second internal electrode 13 is formed on the second ceramic sheet 102. A fired second internal electrode 113 is formed. Note that no internal electrode is formed on the third ceramic sheet 103 corresponding to the cover portion 19.

  The internal electrodes 112 and 113 can be formed using any conductive paste. For example, a screen printing method or a gravure printing method can be used to form the internal electrodes 112 and 113 using a conductive paste.

  The internal electrodes 112 and 113 are disposed over two regions adjacent to each other in the X-axis direction that are partitioned by the cutting line Ly, and extend in a band shape in the Y-axis direction. In the first internal electrode 112 and the second internal electrode 113, the regions partitioned by the cutting line Ly are shifted by one column in the X-axis direction. That is, the cutting line Ly passing through the center of the first internal electrode 112 passes through the region between the second internal electrodes 113, and the cutting line Ly passing through the center of the second internal electrode 113 passes through the region between the first internal electrodes 112. Passing through.

(Step S02: Lamination)
In step S02, the laminated sheet 104 is produced by laminating the ceramic sheets 101, 102, 103 prepared in step S01 in the Z-axis direction (uniaxial direction).

  FIG. 6 is a perspective view of the laminated sheet 104 obtained in step S02. In FIG. 6, for convenience of explanation, the ceramic sheets 101, 102, and 103 are shown in an exploded manner. However, in the actual laminated sheet 104, the ceramic sheets 101, 102, and 103 are integrated by being crimped by hydrostatic pressure or uniaxial pressure. Thereby, the high-density laminated sheet 104 is obtained. As will be described later, the laminated sheet 104 of FIG. 6 is separated into a plurality of laminated chips 116.

In the laminated sheet 104, the first ceramic sheets 101 and the second ceramic sheets 102 corresponding to the capacitance forming unit 18 are alternately laminated in the Z-axis direction.
In the laminated sheet 104, the third ceramic sheets 103 corresponding to the cover portions 19 are laminated on the uppermost and lowermost surfaces in the Z-axis direction of the ceramic sheets 101 and 102 that are alternately laminated. In the example shown in FIG. 6, three third ceramic sheets 103 are laminated, but the number of third ceramic sheets 103 can be changed as appropriate.

(Step S03: Cutting)
In step S03, an unfired laminated chip 116 is produced by cutting the laminated sheet 104 obtained in step S02. In step S03, the laminated sheet 104 is cut by pressing.

  FIG. 7 is a plan view of the laminated sheet 104 after step S03. The laminated sheet 104 is cut along the cutting lines Lx and Ly while being attached to the tape T1 as a holding member. Thereby, the lamination sheet 104 is separated into pieces and the lamination chip 116 is obtained.

  FIG. 8 is a cross-sectional view of the laminated sheet 104 showing the process of step S03. In step S03, the cutting device 200 provided with the cutting blade 20 is used. The cutting blade 20 is configured as a push cutting blade in the present embodiment. Details of the cutting blade 20 and the cutting device 200 will be described later.

First, as shown in FIG. 8A, the cutting blade 20 that is directed downward in the Z-axis direction is disposed above the laminated sheet 104 in the Z-axis direction.
Next, as shown in FIG. 8B, the cutting blade 20 is moved downward in the Z-axis direction until the cutting blade 20 reaches the tape T1, and the laminated sheet 104 is cut. At this time, the cutting blade 20 is not passed through the tape T1, so that the tape T1 is not cut.
Then, as shown in FIG. 8C, the cutting blade 20 is moved upward in the Z-axis direction, and the cutting blade 20 is pulled out from the laminated sheet 104.

Thereby, the laminated sheet 104 is separated into a plurality of laminated chips 116. At this time, the tape T1 connects the laminated chips 116 without being cut. Thereby, it becomes possible to handle a plurality of laminated chips 116 at a time in the subsequent steps, and the manufacturing efficiency is improved.
The cut surfaces of the laminated sheet 104 formed in step S03 become the Y-axis direction side faces P and Q and the X-axis direction end face of the laminated chip 116. In this manner, the multilayer chip 116 having the side surfaces P and Q from which the internal electrodes 112 and 113 are exposed is manufactured by this process.

(Step S04: Side margin portion formation 1)
In step S04, the unfired side margin portion 117 is formed on the side surface P of the multilayer chip 116 obtained in step S03.

  In step S04, a side margin sheet 117s for forming the side margin portion 117 is prepared. The side margin sheet 117s is configured as an unfired dielectric green sheet, similarly to the ceramic sheets 101, 102, and 103 prepared in step S01. The side margin sheet 117s is formed into a sheet shape using, for example, a roll coater or a doctor blade.

FIG. 9 is a cross-sectional view of the laminated chip 116 showing the process of step S04. In step S04, the laminated chip 116 is pasted from the tape T1 to the tape T2, and the side surface Q is held by the tape T2.
First, as shown in FIG. 9A, the side margin sheet 117s is disposed on the flat elastic body 400. The multilayer chip 116 is disposed with the side surface P facing the side margin sheet 117s.
Then, the side surface P of the multilayer chip 116 is pressed against the side margin sheet 117s. As a result, the side margin sheet 117 s is punched out by the side surface P of the multilayer chip 116.

  Thereafter, when the laminated chip 116 is pulled up from the side margin sheet 117s, only the side margin portion 117 punched out from the side margin sheet 117s and attached to the side surface P is removed from the elastic body 400 as shown in FIG. It leaves and remains on the laminated chip 116 side. Thereby, the laminated chip 116 in which the side margin portion 117 is formed on the side surface P is obtained.

The side margin portion 117 on the side surface P of the multilayer chip 116 may be formed by a method other than the above punching.
For example, a side margin sheet 117s cut in advance may be attached to the side surface P of the laminated chip 116.
Further, the side margin portion 117 may be formed by applying a ceramic paste to the side surface P of the multilayer chip 116 without using the side margin sheet 117s. As a method for applying the ceramic paste, for example, a dipping method can be used.

(Step S05: Side margin portion formation 2)
In step S05, an unfired side margin portion 117 is formed on the side surface Q of the multilayer chip 116 obtained in step S04. The formation of the side margin portion 117 on the side surface Q in step S05 can be performed in the same manner as the formation of the side margin portion 117 on the side surface P in step S04.

Thus, the unfired element body 111 shown in FIG. 10 is obtained.
The shape of the element body 111 can be determined according to the shape of the element body 11 after firing. For example, in order to obtain the element body 11 of 1.0 mm × 0.5 mm × 0.5 mm, the element body 111 of 1.2 mm × 0.6 mm × 0.6 mm can be produced.

(Step S06: Firing)
In step S06, the unfired element body 111 obtained in step S05 is fired to produce the element body 11 of the multilayer ceramic capacitor 10 shown in FIGS. Firing can be performed, for example, in a reducing atmosphere or in a low oxygen partial pressure atmosphere.

(Step S07: External electrode formation)
In step S07, the external electrodes 14 and 15 are formed on the element body 11 obtained in step S06, whereby the multilayer ceramic capacitor 10 shown in FIGS.

  In step S07, first, an unfired electrode material is applied so as to cover one X-axis direction end face of the element body 11, and an unfired electrode material is applied so as to cover the other X-axis direction end face of the element body 11. To do. The unfired electrode material applied to the element body 11 is baked, for example, in a reducing atmosphere or a low oxygen partial pressure atmosphere to form a base film on the element body 11. Then, an intermediate film and a surface film are formed on the base film baked on the element body 11 by a plating process such as electroplating, thereby completing the external electrodes 14 and 15.

  Note that part of the processing in step S07 may be performed before step S06. For example, before step S06, an unfired electrode material is applied to both end surfaces in the X-axis direction of the unfired element body 111. In step S06, the unfired element body 111 is fired and at the same time, The underlying layer of the external electrodes 14 and 15 may be formed by baking.

[Details of Cutting Process (Step S03)]
Hereinafter, the cutting process according to the present embodiment will be described in more detail.

FIG. 11 is a side view schematically showing the cutting device 200 used in step S03 of the present embodiment. In the present embodiment, the cutting device 200 functions as a manufacturing apparatus for a multilayer ceramic electronic component.
The cutting device 200 includes a cutting blade 20, a table 21, and a drive unit 22. The cutting device 200 is configured to be able to push through the laminated sheet 104 in the present embodiment.

The table 21 places the laminated sheet 104 thereon. The table 21 has a placement surface 211 for placing the laminated sheet 104 formed, for example, orthogonal to the Z-axis direction. Although not shown, the tape T1 bonded to the laminated sheet 104 may be placed on the placement surface 211.
The table 21 may further have a configuration for fixing the stacked sheet 104 placed thereon, for example, and may have a vacuum suction mechanism as such a configuration, for example.
The table 21 may have a table driving mechanism (not shown). The table drive mechanism may include a motor, for example, and may rotate the mounting surface 211 around the Z axis, or may translate it in the X axis direction and / or the Y axis direction.
The cutting blade 20 is disposed such that the tip portion faces the table 21 in the Z-axis direction.

The drive unit 22 holds the cutting blade 20 and drives the cutting blade 20 in the Z-axis direction with respect to the table 21. The drive unit 22 may include, for example, a holding mechanism that holds the cutting blade 20, a drive mechanism that drives the holding mechanism, and a control unit that controls the drive mechanism.
The holding mechanism is connected to the drive mechanism, and can hold the cutting blade 20 by sandwiching the cutting blade 20, for example.
The drive mechanism includes, for example, a motor, and drives the cutting blade 20 up and down in the Z-axis direction. Further, the drive mechanism may translate the cutting blade 20 in the X-axis direction and / or the Y-axis direction. In this case, the drive mechanism may include a plurality of motors.
The control unit includes, for example, a processor such as an MPU (Micro-Processing Unit) or a CPU (Central Processing Unit), and a memory. The control unit can control the driving of the cutting blade 20 based on the driving program stored in the memory.
Moreover, the drive part 22 is not limited to the structure holding the one cutting blade 20 like a figure, You may hold | maintain the some cutting blade 20. FIG. These cutting blades 20 may be driven by the same drive mechanism, or may be driven separately by different drive mechanisms. For example, the drive unit 22 can perform the cutting operation about 4 or 5 times per second.

  Note that the cutting device 200 may include an input device for operation instructions, data input, and the like in addition to the above configuration. The input device may be configured with buttons, a keyboard, a touch panel, and the like. Moreover, the cutting device 200 may have other configurations as necessary.

  FIG. 12A is a side view showing the cutting blade 20 according to the present embodiment, and FIG. 12B is an enlarged view of a portion surrounded by a two-dot chain line in FIG. The cutting blade 20 has a first surface 201, a second surface 202, and a curved surface 203.

The first surface 201 is formed at the tip end in the Z-axis direction and is inclined at a first angle θ1 with respect to the Z-axis direction. The first angle θ1 is, for example, 5 ° to 20 °, and can be set to 10 ° as an example.
The second surface 202 is formed side by side with the first surface 201 in the Z-axis direction, and is inclined at a second angle θ2 that is smaller than the first angle θ1 with respect to the Z-axis direction. The second angle θ2 is, for example, 0 ° to 15 °, and can be set to 4 ° as an example.
That is, the cutting blade 20 is formed in a two-step taper shape that becomes narrower in the lower direction in the Z-axis direction. In this way, the configuration having the two-step inclination has a viewpoint that it is easy to adjust the thickness of the entire cutting blade 20 by the angle of the second surface while ensuring the strength of the tip portion by a relatively gentle inclination, and ease of extraction. From the point of view, it is advantageous.

  The curved surface 203 smoothly connects the first surface 201 and the second surface 202. Specifically, the curved surface 203 can be a curved surface having an R dimension of 600 μm to 1000 μm.

  Furthermore, at least the first surface of the cutting blade 20 may be mirror-finished. The mirror finish here is a polishing process, for example, a process in which the value of the surface roughness Ra (details will be described later) is less than 0.3 μm.

  By cutting the laminated sheet using the cutting blade 20 having the curved surface 203, it is possible to prevent dragging on the side surfaces P and Q, which are cut surfaces, and to prevent a short circuit failure between the internal electrodes due to this. it can. Hereinafter, the effect of this embodiment is demonstrated in detail using a comparative example.

[Operational effects of this embodiment]
FIG. 13A is a side view showing a cutting blade 30 according to a comparative example of this embodiment, and FIG. 13B is an enlarged view of a portion surrounded by a two-dot chain line in FIG. The cutting blade 30 has a first surface 301 having the same inclination as the first surface 201 and the second surface 202 of the cutting blade 20, and a second surface 302. A corner 303 is formed between the first surface 301 and the second surface 302.

On the other hand, when such a cutting blade 30 is used, drag scratches are formed on the side surfaces P1 and Q1 which are cut surfaces.
FIG. 14 is a diagram illustrating the side surfaces P1 and Q1 of the laminated chip 116 immediately after the cutting process is performed using the cutting blade 30, and FIG. 14A is a schematic diagram illustrating an aspect of the side surfaces P1 and Q1. 14 (B) is an enlarged view of FIG. 14 (A), and FIG. 14 (C) is an enlarged cross-sectional view of side surfaces P1 and Q1.

  On the side surfaces P1 and Q1 shown in FIG. 14A, drag scratch H is formed along the Z-axis direction. Further, as shown in FIG. 14C, fine irregularities caused by the drag scar H are formed on the side surfaces P1 and Q1.

  Further, as shown in FIG. 14B, the extended portions R are formed by extending the internal electrodes 112 and 113 in the Z-axis direction due to the drag H. When the extended portion R reaches the other from one of the internal electrodes 112 and 113, the internal electrodes 112 and 113 are connected to each other via the extended portion R, and a short circuit occurs. Actually, the IR failure rate (initial insulation resistance failure rate) of the multilayer ceramic electronic component manufactured using the cutting blade 30 according to the comparative example was 75%.

  FIG. 15 is a graph showing the relationship between the surface roughness of the cut surface (side surface) and the IR defect rate (initial insulation resistance defect rate) of the multilayer ceramic capacitor, and the horizontal axis represents the surface roughness Ra [nm] of the cut surface. The vertical axis represents the IR defect rate [%].

  The “surface roughness Ra” described below refers to the arithmetic average roughness, and more specifically, that defined in JIS B 0031 (1994). Further, the surface roughness Ra in this test is calculated for a 50 μm × 50 μm region of the cut surface.

As shown in FIG. 15, it was confirmed that the IR defect rate tends to increase almost in proportion to the value of the surface roughness Ra. That is, as the drag scratch H increases, the multilayer ceramic capacitor 10 having the desired performance cannot be obtained.
Therefore, a mechanism for causing the drag H by the cutting blade 30 will be considered.

  FIG. 16 is an enlarged cross-sectional view of the laminated sheet 104 when the laminated sheet 104 is cut using the cutting blade 30 in the cutting step. In addition, in the same figure, illustration of the internal electrodes 112, 113, etc. in the laminated sheet 104 is omitted. In the cutting step, when the cutting blade 30 is moved downward in the Z-axis direction of the laminated sheet 104, the minute region of the laminated sheet 104 facing the first surface 301 has a resistance against the normal force from the first surface 301. Based on this, the frictional force F31 in the direction parallel to the first surface 301 is acting. On the other hand, a frictional force F32 in a direction parallel to the second surface 302 is applied to the minute region of the laminated sheet 104 facing the corner 303 based on the normal resistance from the second surface 302. The frictional force F32 is not parallel to the first surface 301. For this reason, the frictional force F32 acting in the vicinity of the corner 303 acts so as to bite into the cutting surface parallel to the first surface 301 formed in the traveling direction as the cutting blade 30 moves, and the drag wound H is generated. It is thought that it will be formed.

  From this consideration, the drag H is considered to be caused by the corner 303. Therefore, the cutting blade 20 of the present embodiment can prevent the formation of the drag scar H by having the curved surface 203 instead of the corner 303.

  FIG. 17 is an enlarged cross-sectional view of the laminated sheet 104 when the laminated sheet 104 is cut using the cutting blade 20 in the cutting step of Step S03. In addition, in the same figure, illustration of the internal electrodes 112, 113, etc. in the laminated sheet 104 is omitted. In step S03, when the cutting blade 20 is moved downward in the Z-axis direction of the laminated sheet 104, the minute region of the laminated sheet 104 facing the first surface 201 has a resistance against the normal force from the first surface 201. Based on this, the frictional force F21 in the direction parallel to the first surface 201 is acting. This friction force F21 is the same as the friction force F31 according to the comparative example described in FIG. On the other hand, the frictional forces F22, F23, and F24 in the direction in contact with the curved surface 203 act on the minute regions of the laminated sheet 104 facing the curved surface 203 based on the vertical drag from the curved surface 203, respectively. Note that the starting points of the frictional forces F22 to F24 are shown in FIG. 17 so as to be separated from the surface of the cutting blade 20 from F22 to F24, but all are added to a minute region of the laminated sheet 104 facing the curved surface 203. Shall. The angles of these frictional forces F22 to F24 gradually change from the first surface 201 toward the second surface 202. As a result, even when the cutting blade 20 moves downward in the Z-axis direction, a large force that bites into the cutting surface formed in parallel with the first surface 201 does not act, and drag scratches are not easily formed. .

FIG. 18 is a diagram illustrating the side surfaces P and Q of the laminated chip 116 after the cutting process is performed using the cutting blade 20, and FIG. 18A is a schematic diagram illustrating an aspect of the side surfaces P and Q. 18B is an enlarged view of FIG. 18A, and FIG. 18C is an enlarged cross-sectional view of the side surfaces P and Q.
On the side surfaces P and Q shown in FIG. 18 (A), almost no dragging scratches are formed. As shown in FIG. 18C, the side surfaces P and Q are hardly formed with fine irregularities, and the side surfaces P and Q are configured as substantially flat surfaces. The value of the surface roughness Ra of the side surfaces P and Q according to the present embodiment can be set to 20 nm or less, for example.

  For this reason, as shown in FIG. 18B, the extended portions are hardly formed in the internal electrodes 112 and 113, and the occurrence rate of the short circuit is very low. Actually, the IR failure rate (initial insulation resistance failure rate) of the multilayer ceramic capacitor produced using the cutting blade 20 according to the example was 5%.

  As described above, according to the cutting blade 20 of the present embodiment, since the first surface 201 and the second surface 202 are smoothly connected by the curved surface 203, drag scratches that easily occur during cutting occur. Hard to do. Thereby, a short circuit failure between the internal electrodes 112 and 113 can be prevented. Further, by using the cutting blade 20 having at least the first surface 201 having a mirror finish, it is possible to more reliably prevent the occurrence of dragging scratches on the cut surface. Furthermore, according to this embodiment, since the cutting blade 20 of the cutting device 200 can be characterized to prevent the occurrence of scratches on the cut surface, the inner surface can be increased without increasing the number of steps for smoothing the cut surface. A short circuit failure between the electrodes 112 and 113 can be prevented.

[Other Embodiments]
As mentioned above, although embodiment of this invention was described, this invention is not limited only to the above-mentioned embodiment, Of course, a various change can be added.

For example, the steps shown in FIG. 4 may be switched in order as necessary.
As an example, after the unfired laminated chip 116 singulated in step S03 is fired to form the laminated chip 16, the side margin portion 117 may be provided on the laminated chip 16. In this case, steps S04 to S06 can be performed on the laminated chip 16 after firing.

  In the above embodiment, the multilayer ceramic capacitor has been described as an example of the multilayer ceramic electronic component. However, the present invention is applicable to all multilayer ceramic electronic components in which internal electrodes that are paired with each other are alternately arranged. Examples of such a multilayer ceramic electronic component include a piezoelectric element.

DESCRIPTION OF SYMBOLS 10 ... Multilayer ceramic capacitor 11 ... Element body 12, 13 ... Internal electrode 14, 15 ... External electrode 16 ... Multilayer chip 17 ... Side margin part 18 ... Capacitance formation part 19 ... Cover part 104 ... Multilayer sheet 111 ... Unbaked element body 112, 113 ... Unfired internal electrode 116 ... Unfired laminated chip 117 ... Unfired side margin 200 ... Cutting device 20 ... Cutting blade 21 ... Table 22 ... Drive part P, Q ... Sides T1, T2 ... Tape

Claims (4)

Preparing a laminated sheet having ceramic sheets laminated in a uniaxial direction and internal electrodes disposed between the ceramic sheets;
A first surface formed at the tip end in the uniaxial direction and inclined at a first angle with respect to the uniaxial direction, and formed side by side with the first surface in the uniaxial direction, the first surface with respect to the uniaxial direction. possess a second surface inclined at a small second angle than the first angle, and a curved surface smoothly connecting the first surface and the second surface, a, R dimension of the curved surface 600μm~ By cutting the laminated sheet using a cutting blade of 1000 μm, to produce a laminated chip having a side surface where the internal electrode is exposed,
A method of manufacturing a multilayer ceramic electronic component, wherein a side margin is provided on the side surface of the multilayer chip. It is a manufacturing method of the multilayer ceramic electronic component according to claim 1,
Producing the multilayer chip includes cutting using the cutting blade so that the value of the surface roughness Ra of the side surface is 20 nm or less. A method for manufacturing a multilayer ceramic electronic component. It is a manufacturing method of the multilayer ceramic electronic component according to claim 1 or 2,
Producing the multilayer chip includes cutting using the cutting blade having the first surface mirror-finished. A method for manufacturing a multilayer ceramic electronic component. A table on which a laminated sheet having ceramic sheets laminated in a uniaxial direction and internal electrodes disposed between the ceramic sheets is placed;
A first surface formed at the tip end in the uniaxial direction and inclined at a first angle with respect to the uniaxial direction, and formed side by side with the first surface in the uniaxial direction, the first surface with respect to the uniaxial direction. And a curved surface that smoothly connects the first surface and the second surface, and the R dimension of the curved surface is 600 μm to A cutting blade which is 1000 μm and the tip portion is arranged to face the table in the uniaxial direction;
An apparatus for manufacturing a multilayer ceramic electronic component, comprising: a driving unit that holds the cutting blade and drives the cutting blade in the uniaxial direction with respect to the table.

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