JP6828405B2 - Manufacturing method of multilayer ceramic electronic components - Google Patents

Description

The present invention relates to a method for manufacturing a laminated ceramic electronic component.

A multilayer ceramic capacitor is an example of a multilayer ceramic electronic component. In order to manufacture a multilayer ceramic capacitor, for example, a ceramic green sheet on which an internal electrode is formed is laminated, the obtained raw component body is fired, and then an external electrode is attached to the opposite end faces of the sintered component body. To form. As a result, a monolithic ceramic capacitor is obtained in which the internal electrodes drawn out on the end faces on both sides are electrically connected to the external electrodes.

In recent years, as electronic components have become smaller and more sophisticated, multilayer ceramic capacitors are required to be smaller and have higher capacities. In order to reduce the size and increase the capacity of the multilayer ceramic capacitor, it is effective to increase the effective area of the internal electrodes occupying the ceramic green sheet, that is, the area of the internal electrodes facing each other.

For example, Patent Document 1 describes a step of producing a mother block, which includes a plurality of laminated ceramic green sheets and internal electrode patterns arranged along a plurality of interfaces between the ceramic green sheets. By cutting the mother block along a cutting line in the first direction and a cutting line in the second direction orthogonal to each other, it has a laminated structure composed of a plurality of ceramic layers in a raw state and a plurality of internal electrodes. In addition, a step of obtaining a plurality of green chips in which the internal electrodes are exposed on the cutting side surface that appears by cutting along the cutting line in the first direction, and a ceramic paste is applied to the cutting side surface to obtain raw materials. A method for manufacturing a laminated ceramic electronic component including a step of obtaining a raw component body by forming the ceramic protective layer of the above and a step of firing the raw component body is disclosed.

Japanese Patent No. 5678905

In the method described in Patent Document 1, the area of the internal electrodes facing each other is increased by cutting the mother block so that the internal electrodes are exposed on the side surface. However, a method such as dicing is used to cut the mother block, and the internal electrodes hang down due to the stress during cutting. Therefore, the shorter the distance between the internal electrodes, the more the internal electrodes come into contact with each other across the layers. (Hereinafter, also referred to as a short-circuited portion) is likely to occur on the cut side surface. Further, the cut side surface tends to be rough due to the stress at the time of cutting. If chip parts are manufactured in such a state, the short-circuit defect rate at the stage after degreasing increases. From the above, it has been difficult to obtain a good cut side surface in the method for manufacturing a high-capacity multilayer ceramic capacitor.

The above problem is not limited to the case of manufacturing a multilayer ceramic capacitor, but is a common problem in the case of manufacturing a multilayer ceramic electronic component other than a multilayer ceramic capacitor.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for manufacturing a laminated ceramic electronic component having a good cut side surface.

In the first aspect, the method for manufacturing a laminated ceramic electronic component of the present invention includes a plurality of laminated ceramic green sheets and internal electrode patterns arranged along a plurality of interfaces between the ceramic green sheets. , A plurality of ceramic layers in a raw state and a plurality of interiors by cutting the mother block along a cutting line in a first direction and a cutting line in a second direction orthogonal to each other. A step of obtaining a plurality of green chips having a laminated structure composed of electrodes and having the internal electrodes exposed on the cutting side surface appeared by cutting along the cutting line in the first direction, and the cutting side surface. A step of performing a grinding process using abrasive grains, a step of obtaining a raw part body by forming a raw ceramic protective layer on the cut side surface after the grinding process, and a step of firing the raw part body. It is characterized by having a process.

In the first aspect of the present invention, it is possible to remove the sagging of the internal electrode generated during cutting by performing a grinding process using abrasive grains on the cut side surface of the green chip in which the internal electrode is exposed. Therefore, it is possible to prevent the occurrence of a short-circuited portion. As a result, a good cut side surface can be obtained.

In the first aspect of the method for manufacturing a laminated ceramic electronic component of the present invention, a plurality of green chips arranged in row and column directions are spaced apart from each other before the step of performing the grinding process. Further, the step of aligning the cut side surfaces of the plurality of green chips to form an open surface by rolling the plurality of the green chips is further provided, and the above-mentioned grinding is performed on the cut side surface formed as the open surface. It is preferable to carry out the treatment. In this case, it is possible to efficiently perform the grinding process on the cut side surface and the formation of the ceramic protective layer.

In the second aspect, the method for manufacturing a laminated ceramic electronic component of the present invention includes a plurality of laminated ceramic green sheets and internal electrode patterns arranged along a plurality of interfaces between the ceramic green sheets. , A step of manufacturing a mother block and cutting the mother block along a cutting line in the first direction to have a laminated structure composed of a plurality of ceramic layers in a raw state and a plurality of internal electrodes. In addition, a step of obtaining a plurality of rod-shaped green blocks in which the internal electrodes were exposed on the cutting side surface appeared by cutting along the cutting line in the first direction, and abrasive grains were used for the cutting side surface. The step of performing the grinding process, the step of forming the raw ceramic protective layer on the cut side surface after the grinding process, and the rod-shaped green block body on which the raw ceramic protective layer is formed are orthogonal to the first direction. It is characterized by including a step of obtaining a plurality of raw component bodies by cutting along a cutting line in the second direction, and a step of firing the raw component body.

In the second aspect of the present invention, the cut side surface of the rod-shaped green block body in which the internal electrode is exposed is subjected to a grinding process using abrasive grains to remove the sagging of the internal electrode generated during cutting. Therefore, it is possible to prevent the occurrence of a short-circuited portion. As a result, a good cut side surface can be obtained.

In the second aspect of the method for manufacturing a laminated ceramic electronic component of the present invention, a state in which a plurality of rod-shaped green block bodies arranged in a predetermined direction are spaced apart from each other before the step of performing the grinding process. Then, by rolling the plurality of rod-shaped green block bodies, the step of aligning the cut side surfaces of the plurality of rod-shaped green block bodies to form an open surface is further provided, and the above-mentioned open surface is formed. It is preferable to perform the above-mentioned grinding process on the cut side surface. In this case, it is possible to efficiently perform the grinding process on the cut side surface and the formation of the ceramic protective layer.

Hereinafter, when the first aspect and the second aspect of the present invention are not particularly distinguished, it is simply referred to as "the method for manufacturing a laminated ceramic electronic component of the present invention".

In the method for manufacturing a laminated ceramic electronic component of the present invention, the grinding process is preferably a polishing process using free abrasive grains. In the polishing treatment using the free abrasive grains, since the polishing debris is discharged well, the sagging of the internal electrode can be efficiently removed. Further, by periodically supplying the free abrasive grain slurry at room temperature, it is possible to suppress heat generation during processing. Further, by using fine abrasive grains, the surface of the cut side surface can be smoothed.

In the method for manufacturing a laminated ceramic electronic component of the present invention, the grinding process may be a polishing process using fixed abrasive grains. The sagging of the internal electrode can also be removed by the polishing treatment using the fixed abrasive grains.

In the method for producing a laminated ceramic electronic component of the present invention, the average particle size of the abrasive grains is preferably 10 nm or more and 1000 nm or less. By using fine abrasive grains, the resistance at the time of grinding can be lowered, so that the sagging of the internal electrode can be efficiently removed.

In the method for manufacturing a laminated ceramic electronic component of the present invention, the abrasive grains are preferably diamond abrasive grains. Since diamond abrasive grains are excellent in detergency and have little influence on the firing atmosphere, excessive grain growth during firing can be suppressed, and laminated ceramic electronic components of appropriate quality can be manufactured.

In the method for manufacturing a laminated ceramic electronic component of the present invention, the pressure applied to the green chip or the rod-shaped green block body is preferably 0.001 MPa or more and less than 0.010 MPa in the step of performing the grinding process. By controlling the pressure when performing the grinding process, the sagging of the internal electrodes can be efficiently removed.

In the method for manufacturing a laminated ceramic electronic component of the present invention, the surface roughness Ra of the cut side surface after the grinding treatment is preferably 50 nm or less. By reducing the surface roughness of the cut side surface, the short-circuit defect rate can be reduced.

In the method for manufacturing a laminated ceramic electronic component of the present invention, the raw ceramic protective layer is formed by attaching a green sheet for a ceramic protective layer or applying a paste for a ceramic protective layer, and the ceramic protective layer is formed. It is preferable that the green sheet for ceramics or the paste for the ceramic protective layer does not substantially contain Mg. So far, by forming a raw ceramic protective layer using a green sheet for a ceramic protective layer or a paste for a ceramic protective layer containing Mg, a heterogeneous phase is formed at the end of the internal electrode to reduce the short-circuit defect rate. There is a known way to make it. On the other hand, in the method for manufacturing a laminated ceramic electronic component of the present invention, the short-circuit defect rate can be reduced even if the green sheet for the ceramic protective layer or the paste for the ceramic protective layer does not substantially contain Mg. ..

In the method for manufacturing a laminated ceramic electronic component of the present invention, the raw ceramic protective layer is preferably formed by applying a paste for a ceramic protective layer. Compared to the method of attaching the ceramic protective layer green sheet, the method of applying the ceramic protective layer paste causes less damage to the green chip or the rod-shaped green block body when forming the raw ceramic protective layer. .. Therefore, the short defect rate can be further reduced.

In the method for manufacturing a laminated ceramic electronic component of the present invention, the thickness of the ceramic green sheet for manufacturing the mother block is preferably 1 μm or less. In the method for manufacturing a laminated ceramic electronic component of the present invention, since the internal electrodes hang down, the occurrence of short-circuited portions is prevented even when the ceramic green sheet is thin, that is, the distance between the internal electrodes is short. can do.

According to the present invention, it is possible to provide a method for manufacturing a laminated ceramic electronic component having a good cut side surface.

FIG. 1 is a perspective view schematically showing an example of a multilayer ceramic capacitor obtained by the method for manufacturing a multilayer ceramic electronic component of the present invention. FIG. 2 is a perspective view schematically showing an example of a component main body constituting the multilayer ceramic capacitor shown in FIG. 1. FIG. 3 is a perspective view schematically showing an example of a green chip prepared for manufacturing the component body shown in FIG. 2. FIG. 4 is a plan view schematically showing an example of a ceramic green sheet on which an internal electrode pattern prepared for producing the green chip shown in FIG. 3 is formed. 5 (a) is a perspective view for explaining a process of laminating the ceramic green sheet shown in FIG. 4, and FIGS. 5 (b) and 5 (c) are laminated with the ceramic green sheet shown in FIG. It is a top view for demonstrating the process to perform. FIG. 6 is a perspective view for explaining a process of cutting the mother block. FIG. 7 is a perspective view showing a state in which a plurality of green chips arranged in the row and column directions are spaced apart from each other. 8 (a) and 8 (b) are perspective views for explaining a process of rolling the green chip. 9 (a) and 9 (b) are diagrams for explaining a process of performing a grinding process. FIG. 10 is a diagram for explaining a process of forming a raw ceramic protective layer. FIG. 11A is a Ni element mapping image on the cut side surface of the multilayer ceramic capacitor of Comparative Example 1, and FIG. 11B is a Ni element mapping image on the cut side surface of the multilayer ceramic capacitor of Example 1.

Hereinafter, a method for manufacturing the laminated ceramic electronic component of the present invention will be described.
However, the present invention is not limited to the following configurations, and can be appropriately modified and applied without changing the gist of the present invention. It should be noted that a combination of two or more individual desirable configurations of the present invention described below is also the present invention.

As an embodiment of the method for manufacturing a multilayer ceramic electronic component of the present invention, a method for manufacturing a multilayer ceramic capacitor will be described as an example. The manufacturing method of the present invention can also be applied to multilayer ceramic electronic components other than multilayer ceramic capacitors.

First, a multilayer ceramic capacitor obtained by the method for manufacturing a multilayer ceramic electronic component of the present invention will be described.
FIG. 1 is a perspective view schematically showing an example of a multilayer ceramic capacitor obtained by the method for manufacturing a multilayer ceramic electronic component of the present invention. FIG. 2 is a perspective view schematically showing an example of a component main body constituting the multilayer ceramic capacitor shown in FIG. 1.

The multilayer ceramic capacitor 11 shown in FIG. 1 includes a component body 12. As shown in FIG. 2, the component main body 12 has a rectangular parallelepiped shape or a substantially rectangular parallelepiped shape, and has a pair of main surfaces 13 and 14 facing each other and a pair of side surfaces 15 and 16 facing each other. It has a pair of end faces 17 and 18.

FIG. 3 is a perspective view schematically showing an example of a green chip prepared for manufacturing the component body shown in FIG. 2.
As will be described later, the component body 12 shown in FIG. 2 has raw ceramic protective layers 22 and 23 on a pair of side surfaces (hereinafter referred to as cut side surfaces) 20 and 21 of the green chip 19 shown in FIG. 3 facing each other. It is obtained by firing each of the formed products. In the following description, the portion of the component body 12 after firing derived from the green chip 19 will be referred to as a laminated portion 24.

As shown in FIGS. 2 and 3, the laminated portion 24 in the component main body 12 includes a plurality of ceramic layers 25 extending in the directions of the main surfaces 13 and 14 and laminated in a direction orthogonal to the main surfaces 13 and 14, and ceramics. It has a laminated structure composed of a plurality of pairs of internal electrodes 26 and 27 formed along the interface between the layers 25. The component body 12 has a pair of ceramic protective layers 22 and 23 arranged on the cut side surfaces 20 and 21 of the laminated portion 24 so as to provide the side surfaces 15 and 16, respectively. The thicknesses of the ceramic protective layers 22 and 23 are preferably the same as each other.

In addition, in FIGS. 1 and 2, for convenience of explanation, the boundary between the laminated portion 24 and each of the ceramic protective layers 22 and 23 is clearly shown, but such a boundary does not appear clearly. You may.

As shown in FIGS. 2 and 3, the internal electrode 26 and the internal electrode 27 face each other via the ceramic layer 25. When the internal electrode 26 and the internal electrode 27 face each other, electrical characteristics are exhibited. That is, in the multilayer ceramic capacitor 11 shown in FIG. 1, a capacitance is formed.

The internal electrode 26 has an exposed end exposed on the end surface 17 of the component body 12, and the internal electrode 27 has an exposed end exposed on the end surface 18 of the component body 12. On the other hand, since the ceramic protective layers 22 and 23 described above are arranged, the internal electrodes 26 and 27 are not exposed on the side surfaces 15 and 16 of the component body 12.

As shown in FIG. 1, the multilayer ceramic capacitor 11 is further placed on at least one pair of end faces 17 and 18 of the component body 12 so as to be electrically connected to the exposed ends of the internal electrodes 26 and 27, respectively. It includes external electrodes 28 and 29, respectively, which are formed.

The external electrodes 28 and 29 are formed on at least one pair of end faces 17 and 18 of the component body 12, respectively, and in FIG. 1, they wrap around to each part of the main faces 13 and 14 and the side surfaces 15 and 16. Has a part.

As the conductive material constituting the internal electrode, for example, Ni, Cu, Ag, Pd, Ag—Pd alloy, Au or the like can be used.

As the ceramic material constituting the ceramic layers and a ceramic protective layer, for _example, it can be used a dielectric ceramic composed mainly of _{BaTiO 3, CaTiO 3, SrTiO 3} , CaZrO 3 , or the like.

The ceramic material constituting the ceramic protective layer preferably has at least the same main component as the ceramic material constituting the ceramic layer. In this case, it is particularly preferable that a ceramic material having the same composition is used for both the ceramic layer and the ceramic protective layer.

As described above, the manufacturing method of the present invention can be applied to multilayer ceramic electronic components other than multilayer ceramic capacitors. For example, when the laminated ceramic electronic component is a piezoelectric component, a piezoelectric ceramic such as PZT-based ceramic is used, and in the case of a thermista, a semiconductor ceramic such as a spinel-based ceramic is used.

The external electrode is preferably composed of a base layer and a plating layer formed on the base layer. As the conductive material constituting the base layer, for example, Cu, Ni, Ag, Pd, Ag—Pd alloy, Au or the like can be used. The base layer may be formed by applying a conductive paste on the unfired component body and applying a cofire method in which the part body is fired at the same time as the component body, or the conductive paste is applied on the fired component body. It may be formed by applying a post-fire method of baking. Alternatively, the base layer may be formed by direct plating, or may be formed by curing a conductive resin containing a thermosetting resin.

The plating layer formed on the base layer preferably has a two-layer structure of Ni plating and Sn plating on the Ni plating.

Next, as an example of the manufacturing method of the multilayer ceramic electronic component of the present invention, the manufacturing method of the multilayer ceramic capacitor 11 shown in FIG. 1 will be described.

First, a ceramic green sheet to be a ceramic layer is prepared. The ceramic green sheet is formed on a carrier film, for example, by using a die coater, a gravure coater, a micro gravure coater, or the like.

The thickness of the ceramic green sheet is usually 3 μm or less, preferably 1 μm or less, and more preferably 0.6 μm or less.

Next, the conductive paste is printed on the ceramic green sheet with a predetermined pattern.

FIG. 4 is a plan view schematically showing an example of a ceramic green sheet on which an internal electrode pattern prepared for producing the green chip shown in FIG. 3 is formed.
As shown in FIG. 4, an internal electrode pattern 32 to be each of the internal electrodes 26 and 27 is formed by printing a conductive paste with a predetermined pattern on the ceramic green sheet 31 to be the ceramic layer 25. Will be done. Specifically, a plurality of rows of band-shaped internal electrode patterns 32 are formed on the ceramic green sheet 31.

The thickness of the internal electrode pattern is not particularly limited, but is preferably 1.5 μm or less.

After that, a predetermined number of ceramic green sheets on which the internal electrode pattern is formed are laminated while being shifted, and a predetermined number of ceramic green sheets on which the internal electrode pattern is not formed are laminated above and below the ceramic green sheets.

FIG. 5A is a perspective view for explaining a process of laminating the ceramic green sheets shown in FIG.
As shown in FIG. 5A, a predetermined number of ceramic green sheets 31 on which the internal electrode pattern 32 is formed are laminated at predetermined intervals along the width direction, that is, while shifting by half the width direction dimension of the internal electrode pattern 32. .. Further, a predetermined number of ceramic green sheets on which the internal electrode pattern is not printed are laminated on the upper and lower surfaces thereof.

5 (b) and 5 (c) are plan views for explaining a step of laminating the ceramic green sheets shown in FIG. 5 (b) and 5 (c) show enlarged ceramic green sheets of the first layer and the second layer, respectively.
5 (b) and 5 (c) show the cutting lines 33 in the width direction (vertical direction in FIGS. 5 (b) and 5 (c)) orthogonal to the direction in which the band-shaped internal electrode pattern 32 extends. , Each part of the cutting line 34 in the longitudinal direction (the left-right direction in FIGS. 5B and 5C) orthogonal to this is shown. The band-shaped internal electrode pattern 32 has a shape in which two internal electrodes 26 and 27 are connected to each other by the drawer portions, and are continuous along the longitudinal direction. In FIGS. 5 (b) and 5 (c), cutting lines 33 and 34 are shown in common.

As a result of the laminating step, a mother block including a plurality of laminated ceramic green sheets and internal electrode patterns arranged along a plurality of interfaces between the ceramic green sheets is obtained. The obtained mother block is pressed in the stacking direction by means such as a hydrostatic pressure press.

A plurality of green chips are obtained by cutting the pressed mother blocks along a cutting line in the first direction and a cutting line in the second direction that are orthogonal to each other. For this cutting, for example, methods such as dicing, push-cutting, and laser cutting are applied.

FIG. 6 is a perspective view for explaining a process of cutting the mother block.
In FIG. 6, the mother block 35 is cut along a cutting line 33 in the first direction and a cutting line 34 in the second direction orthogonal to each other to obtain a plurality of green chips 19 arranged in the row and column directions. In FIG. 6, the uppermost internal electrode pattern 32 located inside the mother block 35 is shown by a broken line. In FIG. 6, six green chips 19 are taken out from one mother block 35, but in reality, a larger number of green chips 19 are taken out.

As shown in FIG. 3, each green chip 19 has a laminated structure composed of a plurality of ceramic layers 25 in a raw state and a plurality of internal electrodes 26 and 27. The cut side surfaces 20 and 21 of the green chip 19 are surfaces that are revealed by cutting along the cutting line 33 in the first direction, and the cut end faces 36 and 37 are surfaces that are revealed by cutting the cutting line 34 in the second direction. All of the internal electrodes 26 and 27 are exposed on the cut side surfaces 20 and 21. Further, only the internal electrode 26 is exposed on one cut end face 36, and only the internal electrode 27 is exposed on the other cut end face 37.

As shown in FIG. 6, the mother block 35 may be cut while being attached to the expandable adhesive sheet 38 so that the plurality of green chips 19 are arranged in the row and column directions. preferable. In this case, the adhesive sheet 38 can be expanded by an expanding device (not shown).

FIG. 7 is a perspective view showing a state in which a plurality of green chips arranged in the row and column directions are spaced apart from each other.
By expanding the adhesive sheet 38 shown in FIG. 6, as shown in FIG. 7, the plurality of green chips 19 arranged in the row and column directions are brought into a state in which the distance between them is widened.

Subsequently, it is preferable to perform a rolling step in which the cut side surfaces of the plurality of green chips are aligned to form an open surface by rolling the plurality of green chips.

8 (a) and 8 (b) are perspective views for explaining a process of rolling the green chip.
By rotating the green tip 19 shown in FIG. 8 (a) by 90 degrees, as shown in FIG. 8 (b), the cut side surface 20 can be an open surface facing upward.

Grinding processing using abrasive grains is performed on the cut side surface. When the above-mentioned rolling step is performed, it is preferable that the grinding process is performed on the cut side surface facing upward by the rolling step.

The grinding process may be performed at any stage after cutting the mother block and before forming the raw ceramic protective layer. Therefore, for example, the cutting surface before the rolling process may be subjected to the grinding process, or the cutting surface obtained by cutting may be subjected to the grinding process without performing the rolling process.

9 (a) and 9 (b) are diagrams for explaining a process of performing a grinding process. 9 (a) and 9 (b) are enlarged views of the vicinity of the cut side surface shown from the end face direction of the green chip.
As shown in FIG. 9A, a sagging 26A of the internal electrode 26 exists on the cutting side surface 20 due to the stress at the time of cutting. By performing a grinding process on the cut side surface 20 to the position of the grinding line XX shown in FIG. 9A, the sagging 26A of the internal electrode 26 can be removed as shown in FIG. 9B. it can.

The grinding process includes, for example, a grinding process using fixed abrasive grains (dicing, grinding, etc.), a polishing process using fixed abrasive grains (dry polishing, tape polishing, etc.), and a polishing process using free abrasive grains (wrapping). , Polishing, etc.). These processes may be combined. The grinding process by dicing can be performed by performing two dicings on the mother block, and the first dicing is distinguished as the cutting process and the second dicing as the grinding process. In this case, it is preferable that the average particle size of the abrasive grains used for the second dicing is smaller than the average particle size of the abrasive grains used for the first dicing.

From the viewpoint of preventing the occurrence of short-circuited portions, polishing treatment using fixed abrasive grains or polishing treatment using free abrasive grains is preferable, and from the viewpoint of smoothing the surface of the cut side surface, the free abrasive grains are used. The polishing treatment used is more preferable. As the polishing treatment using the fixed abrasive grains, tape polishing is preferable. Polishing is preferable as the polishing treatment using free abrasive grains. In this case, only polishing may be performed, or polishing may be performed after wrapping as a pretreatment. The size of the abrasive grains differs between lapping and polishing, and the polishing process using abrasive grains larger than polishing is called lapping.

In the grinding process using abrasive grains, the average particle size of the abrasive grains is preferably 10 nm or more, more preferably 50 nm or more, and further preferably 100 nm or more. The average particle size of the abrasive grains is preferably 1000 nm or less. In particular, when polishing treatment such as polishing is performed, the average particle size of the abrasive grains is more preferably 800 nm or less, and further preferably 500 nm or less. By using fine abrasive grains, the resistance at the time of grinding can be lowered, so that the sagging of the internal electrode can be efficiently removed.

In the grinding process using abrasive grains, the material of the abrasive grains is not particularly limited, but diamond abrasive grains are preferable. Since diamond abrasive grains are excellent in detergency and have little influence on the firing atmosphere, excessive grain growth during firing can be suppressed, and laminated ceramic electronic components of appropriate quality can be manufactured.

In the grinding process using abrasive grains, the pressure applied to the green tip is preferably 0.001 MPa or more. In particular, when polishing treatment such as polishing is performed, the pressure applied to the green chip is more preferably 0.005 MPa or more. The pressure applied to the green chip is preferably less than 0.010 MPa, more preferably less than 0.008 MPa. By controlling the pressure when performing the grinding process, the sagging of the internal electrodes can be efficiently removed.

The surface roughness Ra of the cut side surface after the grinding treatment is preferably 50 nm or less, and more preferably 20 nm or less. By reducing the surface roughness of the cut side surface, the short-circuit defect rate can be reduced.
The surface roughness Ra can be measured using an optical interference type surface roughness meter (NewView manufactured by ZYGO).

After the grinding process, a raw ceramic protective layer is formed on the cut side surface. The raw ceramic protective layer is formed, for example, by attaching a green sheet for the ceramic protective layer or applying a paste for the ceramic protective layer.

FIG. 10 is a diagram for explaining a process of forming a raw ceramic protective layer.
As shown in FIG. 10, the raw ceramic protective layer 22 can be formed by attaching the ceramic protective layer green sheet to the cut side surface 20 after the grinding treatment or by applying the ceramic protective layer paste. it can.

It is preferable that the green sheet for the ceramic protective layer or the paste for the ceramic protective layer contains the same ceramic raw material as the main component as the ceramic green sheet for producing the mother block.

Further, it is preferable that the green sheet for the ceramic protective layer or the paste for the ceramic protective layer does not substantially contain Mg.

After forming the raw ceramic protective layer, a drying step is performed if necessary. In the drying step, the green chips 19 on which the raw ceramic protective layer 22 is formed are placed in, for example, an oven set at 120 ° C. for 5 minutes.

Next, it is preferable that a rolling step similar to the step described with reference to FIG. 8 is performed. That is, it is preferable that the rolling step is performed by rolling the plurality of green chips so that the cut side surfaces of the plurality of green chips are aligned to form an open surface. In this case, by rotating the green tip 180 degrees, the cut side surface on the opposite side can be made an open surface facing upward.

The cut side surface on the opposite side may also be subjected to a grinding process using abrasive grains in the same manner as described above to form a raw ceramic protective layer. The conditions of the grinding process may be the same or different. In addition, after forming the raw ceramic protective layer, a drying step is performed if necessary. From the above, a raw component body is obtained.

The resulting raw part body is fired. The firing temperature is, for example, in the range of 900 ° C. or higher and 1300 ° C. or lower, although it depends on the ceramic material and the metal material contained in the raw component body.

External electrodes 28 and 29 are formed by applying a conductive paste to both end faces 17 and 18 of the component body after firing, baking the paste, and plating if necessary. The conductive paste may be applied to the raw component body, or the conductive paste may be baked at the same time as the raw component body is fired.

In this way, the monolithic ceramic capacitor 11 shown in FIG. 1 is manufactured.

In the above-described embodiment, the mother block is cut into a cutting line in the first direction and a cutting line in the second direction to obtain a plurality of green chips, and then the cut side surface is ground to obtain a raw ceramic protective layer. Was formed, but it can be changed as follows.

That is, by cutting the mother block only along the cutting line in the first direction, a plurality of rod-shaped green blocks in which the internal electrodes are exposed on the cutting side surface appeared by the cutting along the cutting line in the first direction are obtained. Then, the cut side surface is ground to form a raw ceramic protective layer, and then cut into a cutting line in the second direction to obtain a plurality of raw component bodies, and then the raw component body is formed. It may be fired. After firing, a laminated ceramic electronic component can be manufactured by performing the same steps as in the above-described embodiment.

Hereinafter, examples will be described in which the method for manufacturing the laminated ceramic electronic component of the present invention is disclosed more specifically. The present invention is not limited to these examples.

[Manufacturing of multilayer ceramic capacitors]
(Example 1)
A polyvinyl butyral binder, a plasticizer, and ethanol as an organic solvent were added to BaTIO ₃ as a ceramic raw material, and these were wet-mixed with a ball mill to prepare a ceramic slurry. Next, this ceramic slurry was sheet-molded by the lip method to obtain a rectangular ceramic green sheet. Next, a conductive paste containing Ni was screen-printed on the ceramic green sheet to form an internal electrode pattern containing Ni as a main component.

A mother block was obtained by laminating a plurality of ceramic green sheets on which the internal electrode pattern was formed while shifting them in the width direction, and laminating ceramic green sheets on which the internal electrode pattern was not printed. The obtained mother block was pressed in the stacking direction by a hydrostatic pressure press.

By cutting the pressed mother block into a chip shape, a green chip in which individual internal electrodes were exposed on both end surfaces and both side surfaces was obtained. After cutting, ultrasonic cleaning was performed with pure water.

One cut side surface of the green chip was subjected to a polishing treatment using free abrasive grains as a grinding treatment. In Example 1, polishing was performed using a diamond slurry (abrasive) having an average particle diameter of 0.5 μm and a cotton cloth-based polishing pad. The polishing conditions were a revolution speed of 20 rpm, an applied pressure of 7 kPa, and a time of 10 minutes.

After the polishing treatment, ultrasonic cleaning was performed with pure water, and then the water content was dried. Subsequently, a green sheet for a ceramic protective layer was attached to the cut side surface after the polishing treatment to form a raw ceramic protective layer. The composition of the green sheet for the ceramic protective layer is the same as the composition of the ceramic green sheet.

The other cut side surface of the green chip was also subjected to a polishing treatment using free abrasive grains in the same manner as described above, and then a raw ceramic protective layer was formed. As a result, a raw component body was obtained.

The obtained raw component body was degreased in a nitrogen atmosphere and then calcined in a hydrogen / nitrogen mixed atmosphere. After firing, an external electrode was formed by applying and baking a conductive paste to prepare a multilayer ceramic capacitor of Example 1.

(Example 2)
A green chip was produced by the same method as in Example 1. One cut side surface of the green chip was subjected to a polishing treatment using fixed abrasive grains as a grinding treatment. In Example 2, as the polishing treatment, tape polishing using a polishing tape provided with an abrasive having an average particle diameter of 0.5 μm was performed. The conditions for tape polishing were a speed of 50 mm / sec, an applied pressure of 10 kPa, and a number of reciprocations of 25 times.

Then, as in Example 1, a raw ceramic protective layer was formed. The other cut side surface of the green chip was also subjected to a polishing treatment using fixed abrasive grains in the same manner as described above, and then a raw ceramic protective layer was formed. In addition, the external electrodes were formed by the same method as in Example 1 to produce the multilayer ceramic capacitor of Example 2.

(Comparative Example 1)
The external electrodes were formed in the same manner as in Example 1 except that the cut side surface of the green chip was not ground, and the multilayer ceramic capacitor of Comparative Example 1 was produced.

[Evaluation]
(Complete short circuit)
Using a scanning electron microscope (SEM), the cut side surface before forming the external electrode was photographed at a magnification of 7000 times. Among the 14 to 16 internal electrodes, the number of points where the Ni particles were in contact with each other completely across the layers was measured. The results are shown in "Complete short circuit points" in Table 1. When the number of completely short-circuited points was 0, it was evaluated as ⊚ (excellent), and when it was 1 or more, it was evaluated as × (impossible).

(Surface roughness)
Using a light interference type surface roughness meter (NewView manufactured by ZYGO), the surface roughness Ra of the cut side surface before forming the external electrode was measured. The results are shown in "Surface Roughness" in Table 1. When the surface roughness Ra was 20 nm or less, it was evaluated as ⊚ (excellent), when it was larger than 20 nm and 50 nm or less, it was evaluated as ◯ (good), and when it was larger than 50 nm, it was evaluated as × (impossible).

(Short rate after degreasing)
The capacitance of each of 100 multilayer ceramic capacitors was measured with an LCR meter, and the occurrence rate of short-circuit defects was calculated. The results are shown in "Short rate after degreasing" in Table 1. When the short-circuit rate after degreasing was less than 80%, it was evaluated as ⊚ (excellent), when it was 80% or more and less than 100%, it was evaluated as ◯ (good), and when it was 100%, it was evaluated as × (impossible).

As shown in Table 1, in Comparative Example 1 in which the cut side surface was not ground after cutting the mother block and before forming the raw ceramic protective layer, a completely short-circuited portion was generated. On the other hand, in Examples 1 and 2 in which the cut side surface was ground, the number of completely short-circuited portions was 0. In particular, in Example 1 in which the polishing treatment using free abrasive grains was performed, the surface roughness of the cut side surface after the polishing treatment was small, and the short-circuit rate after degreasing was significantly lower than in Comparative Example 1.

FIG. 11A is a Ni element mapping image on the cut side surface of the multilayer ceramic capacitor of Comparative Example 1, and FIG. 11B is a Ni element mapping image on the cut side surface of the multilayer ceramic capacitor of Example 1.
Similar to the results in Table 1, in Comparative Example 1 in which the cut side surface was not ground, as shown in FIG. 11 (a), the completely short-circuited portion (the portion circled in FIG. 11 (a)). ) Was confirmed, whereas in Example 1 in which the cut side surface was ground, a completely short-circuited portion was not confirmed as shown in FIG. 11 (b).

11 Multilayer ceramic capacitors (multilayer ceramic electronic components)
12 Part body 13, 14 Main surface 15, 16 Side surface 17, 18 End surface 19 Green chip 20, 21 Cut side surface 22, 23 Ceramic protective layer 24 Laminated part 25 Ceramic layer 26, 27 Internal electrode 26A Internal electrode sag 28, 29 External Electrode 31 Ceramic green sheet 32 Internal electrode pattern 33 Cutting line in the first direction 34 Cutting line in the second direction 35 Mother block 36, 37 Cut end face 38 Adhesive sheet

Claims (11)

A step of producing a mother block, which includes a plurality of laminated ceramic green sheets and internal electrode patterns arranged along a plurality of interfaces between the ceramic green sheets.
By cutting the mother block along a cutting line in the first direction and a cutting line in the second direction orthogonal to each other, a laminated structure composed of a plurality of ceramic layers in a raw state and a plurality of internal electrodes is formed. A step of obtaining a plurality of green chips having, and having the internal electrodes exposed on the cutting side surface that appears by cutting along the cutting line in the first direction.
A step of performing a grinding process using abrasive grains on the cut side surface, and
The process of obtaining a raw part body by forming a raw ceramic protective layer on the cut side surface after the grinding process, and
The process of firing the raw part body is provided .
Prior to the step of performing the grinding process, the plurality of green chips are rolled by rolling the plurality of green chips in a state where the plurality of green chips arranged in the row and column directions are widely spaced from each other. Further provided with a step of aligning the cut side surfaces of each of the above to make an open surface.
A method for manufacturing a laminated ceramic electronic component, which comprises performing the grinding process on the cut side surface formed as an open surface . A step of producing a mother block, which includes a plurality of laminated ceramic green sheets and internal electrode patterns arranged along a plurality of interfaces between the ceramic green sheets.
By cutting the mother block along the cutting line in the first direction, the mother block has a laminated structure composed of a plurality of ceramic layers in a raw state and a plurality of internal electrodes, and the cutting in the first direction. A step of obtaining a plurality of rod-shaped green blocks in which the internal electrodes are exposed on the cut side surface that appears by cutting along the line, and
A step of performing a grinding process using abrasive grains on the cut side surface, and
The step of forming a raw ceramic protective layer on the cut side surface after the grinding process, and
A step of obtaining a plurality of raw component bodies by cutting the rod-shaped green block body on which the raw ceramic protective layer is formed along a cutting line in a second direction orthogonal to the first direction.
The process of firing the raw part body is provided .
Prior to the step of performing the grinding process, a plurality of the rod-shaped green block bodies arranged in a predetermined direction are rolled in a state where the distance between the rod-shaped green block bodies is widened. Further provided with a step of aligning the cut side surfaces of each of the rod-shaped green block bodies to form an open surface.
A method for manufacturing a laminated ceramic electronic component, which comprises performing the grinding process on the cut side surface formed as an open surface . The method for manufacturing a laminated ceramic electronic component according to claim 1 or 2 , wherein the grinding process is a polishing process using free abrasive grains. The method for manufacturing a laminated ceramic electronic component according to claim 1 or 2 , wherein the grinding process is a polishing process using fixed abrasive grains. The method for manufacturing a laminated ceramic electronic component according to any one of claims 1 to 4 , wherein the average particle size of the abrasive grains is 10 nm or more and 1000 nm or less. The method for manufacturing a laminated ceramic electronic component according to any one of claims 1 to 5 , wherein the abrasive grains are diamond abrasive grains. The laminated ceramic electron according to any one of claims 1 to 6 , wherein the pressure applied to the green chip or the rod-shaped green block body in the step of performing the grinding process is 0.001 MPa or more and less than 0.010 MPa. How to manufacture parts. The method for manufacturing a laminated ceramic electronic component according to any one of claims 1 to 7 , wherein the surface roughness Ra of the cut side surface after the grinding treatment is 50 nm or less. The raw ceramic protective layer is formed by attaching a green sheet for a ceramic protective layer or applying a paste for a ceramic protective layer.
The method for producing a laminated ceramic electronic component according to any one of claims 1 to 8 , wherein the green sheet for the ceramic protective layer or the paste for the ceramic protective layer does not substantially contain Mg. The method for manufacturing a laminated ceramic electronic component according to any one of claims 1 to 9 , wherein the raw ceramic protective layer is formed by applying a paste for a ceramic protective layer. The method for manufacturing a laminated ceramic electronic component according to any one of claims 1 to 10 , wherein the thickness of the ceramic green sheet for manufacturing the mother block is 1 μm or less.

Images