JP4160858B2 - Manufacturing method of multilayer ceramic electronic component - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a multilayer ceramic electronic component such as a multilayer ceramic capacitor, a multilayer varistor, a multilayer chip inductor, and a multilayer wiring board.
[0002]
[Prior art]
Conventionally, a multilayer ceramic electronic component such as a multilayer ceramic capacitor is usually manufactured by a multi-cavity technique.
[0003]
Specifically, for example, a temporary laminate is formed by laminating a plurality of ceramic green sheets having a substantially uniform thickness with a predetermined conductor pattern interposed therebetween, and a plurality of components constituting the temporary laminate are formed. The individual ceramic green sheets are pressure-bonded to each other by a conventionally known press forming method, and the pressure-bonded laminate is cut with a cutter for each substrate area corresponding to each multilayer ceramic electronic component. A plurality of monolithic ceramic electronic components can be obtained simultaneously by firing.
[0004]
In the conventional manufacturing method described above, an isostatic press is used to press-mold the temporary laminate. In this hydrostatic press, first, the above-mentioned temporary laminate is placed on the upper surface of a flat rigid plate made of stainless steel, stainless alloy, aluminum or the like, and this is applied to an outer package made of a flexible material such as rubber or plastic. Then, the inside of the outer package is degassed and sealed, thereby bringing the inner surface of the outer package into close contact with the upper surface and peripheral surface of the temporary laminate and the lower surface of the rigid plate. Next, the temporary laminate wrapped with the outer envelope is placed in a pressure vessel of a hydrostatic press, and a pressurized fluid is injected into the pressure vessel to generate a high pressure in the pressure vessel. This is performed by pressurizing the laminated body from the periphery of the outer package so that the ceramic green sheets constituting the temporary laminated body are pressed against each other.
[0005]
Further, each substrate region of the obtained pressure-bonded laminate includes a region where a large amount of conductive paste is interposed therein, a region where no conductive paste is present, or a region where almost no conductive paste is interposed. Since the thickness of the pressure-bonded laminate is different between the two regions, the surface that was in contact with the rigid body in the hydrostatic pressing process described above is a flat surface, whereas the surface that was in contact with the outer envelope As a result, unevenness due to the presence or absence of the conductor paste is formed (for example, see Patent Document 1).
[0006]
Then, in the step of dividing the pressure-bonded laminate, as shown in FIG. 6, the pressure-bonded laminate is placed on the split stage 20 with the flat surface that was in contact with the rigid plate facing down during the hydrostatic pressing. A plurality of multilayer ceramic electronic components corresponding to the individual substrate regions 22 are obtained by cutting along the outer periphery of each substrate region 22 from above the pressure-bonded laminate using the cutter 21.
[0007]
[Patent Document 1]
JP-A-4-72864 [0008]
[Problems to be solved by the invention]
However, according to the above-described conventional method for manufacturing a multilayer ceramic electronic component, the lower surface of the pressure-bonded laminated body arranged so as to be in contact with the rigid body in the isostatic pressing process is flat. Therefore, when the cutter 21 is inserted from above the pressure-bonded laminated body with the flat surface in contact with the upper surface of the split stage 20, the corner between the lower surface and the side surface of the individual piece 22 obtained by the split is obtained. In many cases, “burrs”, “chips”, and the like occur, which has been one of the causes for significantly reducing the productivity of multilayer ceramic electronic components.
[0009]
The present invention has been devised in view of the above-described problems, and its purpose is to “burr” and “chip” at the corners between the bottom surface and the side surface of the multilayer ceramic electronic component obtained by division from the pressure-bonded laminate. It is an object of the present invention to provide a method for manufacturing a multilayer ceramic electronic component that can effectively prevent the occurrence of the above and improve productivity.
[0010]
[Means for Solving the Problems]
The method for manufacturing a multilayer ceramic electronic component according to the present invention includes a plurality of ceramic green sheets having a plurality of substrate regions, and a plurality of conductor patterns corresponding to the substrate regions between the substrate regions. A step of preparing a temporary laminated body formed by stacking, and placing the temporary laminated body on the flat portion of a rigid plate having a flat portion on at least an upper surface, and allowing the rigid plate and the temporary laminated body to be The inner surface of the outer envelope body is tightly attached to the upper surface and the peripheral surface of the temporary laminated body and the lower surface of the rigid plate by being stored in a flexible outer envelope body and deaerated and sealed in the outer envelope body. Placing the temporary laminate and the rigid plate in a pressure vessel filled with a pressurized fluid in a state where the temporary laminate and the rigid plate are accommodated in the outer envelope, and hydrostatically pressing the temporary laminate with the pressurized fluid. To form a pressure-bonded laminate. Forming a depression corresponding to the boundary portion of the substrate region on the upper surface of the pressure-bonded laminate, and then removing the pressure-bonded laminate from the outer package; and an upper surface of the pressure-bonded laminate on which the depression is formed. Is placed on the split stage facing down, and after that, by using a cutter, the pressure-bonded laminate is cut from the lower surface side of the pressure-bonded laminate along the outer periphery of each substrate region. And obtaining a plurality of laminated ceramic electronic components.
[0011]
According to the method for manufacturing a multilayer ceramic electronic component of the present invention, the pressure-bonded laminate is formed with the upper surface of the pressure-bonded laminate in which a depression is formed at a position corresponding to the outer periphery of each substrate region facing the divided stage in the hydrostatic press process Since the pressure-bonded laminate is divided by inserting a cutter from the lower surface side of the flatly formed pressure-bonded laminate, the depression on the upper surface of the pressure-bonded laminate is formed during this division. It functions as an end point of the division, and the occurrence of “burrs”, “chips” and the like in the individual multilayer ceramic electronic parts obtained by the division is effectively prevented. Thereby, the productivity of the multilayer ceramic electronic component can be improved.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a method for producing a multilayer ceramic electronic component of the present invention will be described with reference to the accompanying drawings.
[0013]
FIG. 1 is a cross-sectional view showing a multilayer ceramic capacitor as a multilayer ceramic electronic component manufactured by the manufacturing method of the present invention, wherein 1 is a multilayer body, 2 is a dielectric layer, 3 is a first internal electrode, and 4 is a second layer. The internal electrodes 5a and 5b are a pair of external electrodes.
[0014]
The multilayer ceramic capacitor shown in FIG. 1 is formed by laminating a plurality of rectangular dielectric layers 2 to form a substantially rectangular parallelepiped laminate 1, and within each laminate 1, each dielectric layer 2-2 is formed. 2, the first internal electrode 3 and the second internal electrode 4 are alternately interposed in a partially opposed state, and both main surfaces located in the vicinity of each end surface from both end surfaces of the laminate 1 and It has a structure in which external electrodes 5a and 5b are deposited and formed on the side surfaces.
[0015]
The plurality of first internal electrodes 3 disposed inside the multilayer body 1 are commonly connected to the external electrode 5a on one end surface side of the multilayer body 1, and the plurality of second internal electrodes 4 are The other end surface of the multilayer body 1 is commonly connected to the external electrode 5b, and when an electric field is applied between the pair of external electrodes 5a and 5b, the first internal electrode 3 and the second internal electrode 4 A predetermined capacitance corresponding to the dielectric constant, thickness, opposing area, and number of layers of the dielectric layer 2 positioned therebetween is formed.
[0016]
The dielectric layer 2 is formed to a thickness of 1 μm to 3 μm per layer by a dielectric material mainly composed of, for example, barium titanate, calcium titanate, strontium titanate, etc. 1 internal electrode 3 and 2nd internal electrode 4 are formed by the conductor material which has metals, such as nickel, copper, nickel / copper, silver / palladium, as a main component, for example in the thickness of 0.5 micrometer-1.5 micrometers. The opposing area of both internal electrodes is set to 0.04 to 30 mm ² , for example.
[0017]
Further, when the first and second inner electrodes 3 and 4 are made of nickel / copper, the outer electrodes 5a and 5b are formed to a thickness of 20 μm to 150 μm, for example, with a conductor material mainly composed of copper, and the surface thereof In order to improve the solder wettability of the surface when soldering the multilayer ceramic capacitor onto the wiring board, nickel plating, gold plating, or the like is applied.
[0018]
Next, a method for manufacturing the above-described multilayer ceramic capacitor will be described with reference to FIGS.
[0019]
(Process 1)
First, as shown in FIG. 2, a temporary laminate 11 in which a plurality of ceramic green sheets 12 are laminated is prepared.
[0020]
The temporary laminated body 11 has a size that allows a plurality of laminated ceramic capacitors to be cut out, and has a plurality of substrate regions 10 corresponding to the laminated ceramic capacitors.
[0021]
The plurality of ceramic green sheets 12 constituting the temporary multilayer body 11 are for forming the dielectric layer 2 of the multilayer ceramic capacitor. For example, the dielectric layer 2 is composed mainly of barium titanate. In the case of consisting of a dielectric material, an appropriate organic solvent, glass frit, organic binder, etc. are added to and mixed with the barium titanate powder to form a slurry, and this is adopted using a conventionally known doctor blade method, It is formed by processing into a sheet with a predetermined shape and a predetermined thickness, and the obtained ceramic green sheets 12 are temporarily laminated by preliminarily laminating them one by one using a conventionally known green sheet laminating method or the like. A body 11 is produced.
[0022]
The temporary laminate 11 includes a plurality of conductor patterns 13 and 14 corresponding to the substrate region 10 between the ceramic green sheets 12-12, specifically, the first internal electrodes 3. The conductive pattern 13 to be formed and the conductive pattern 14 to be the second internal electrode 4 are alternately interposed so as to partially face each other.
[0023]
When the first and second internal electrodes 3 and 4 are made of nickel / copper, the conductor patterns 13 and 14 are prepared by adding and mixing an appropriate organic solvent, glass frit, organic binder, etc. to the nickel / copper powder. The obtained conductor paste is printed and applied in a predetermined pattern on one main surface of each ceramic green sheet 12 by a conventionally known screen printing method or the like before the above-described ceramic green sheets 12 are laminated. 12-12. In addition, the dielectric material contained in the ceramic green sheet 12 may be added and mixed separately in the above-described conductor paste.
[0024]
At this time, inside the temporary laminate 11, there are areas where the conductor patterns 13, 14 are present in large numbers and areas where there are not so many, specifically, the conductor patterns 13, 14 between all the ceramic green sheets. There is a central portion of each existing substrate region and a peripheral portion of each substrate region in which the conductor pattern 13 or the conductor pattern 14 is interposed every two layers of the ceramic green sheet, and a boundary portion between adjacent substrate regions 10 In FIG. 5, only one of the conductor pattern 13 and the conductor pattern 14 is present.
[0025]
(Process 2)
Next, the temporary laminate 11 obtained in step 1 is placed on the flat portion of the rigid plate 16 having a flat portion on the upper surface, and the rigid plate 16 and the temporary laminate 11 are placed inside the outer package 17. It is stored and the inside of the outer package 17 is deaerated and sealed.
[0026]
The rigid plate 16 is formed with a predetermined thickness from a metal material such as stainless steel, stainless alloy, or aluminum, and supports the temporary laminate 11 with a flat portion provided on the upper surface thereof. Such a rigid plate 16 needs to have a rigidity that does not cause a large deformation in the hydrostatic press process described later. For example, a rockwell C scale hardness such as SUS430, SKD11, or SKH51 having a hardness of 55 HRC or more. It is preferable to use it.
[0027]
Further, the outer packaging body 17 is formed into a bag shape by a flexible material having appropriate flexibility and capable of degassing and sealing the inside, such as rubber, nylon, and other plastics. The temporary laminated body 11 and the rigid plate 16 described above are accommodated in the outer packaging body 17 and the air in the outer packaging body 17 is discharged using a vacuum device or the like. The temporary laminate 11 is sealed by sealing the seal portion by heat welding or the like. Thus, by vacuum packing using the outer package 17, the inner surface of the outer package 17 is brought into close contact with the upper surface and peripheral surface of the temporary laminate 11 and the lower surface and side surfaces of the rigid plate 16.
[0028]
At this time, the degree of vacuum inside the outer package 17 is preferably set to −0.1 mPa or less, for example.
[0029]
(Process 3)
Next, as shown in FIG. 3, the temporary laminate 11 and the rigid plate 16 are placed in the outer container 17 and placed in the pressure vessel 15 of the hydrostatic press device into which the pressurized fluid 18 is injected, The temporary laminate 11 is hydrostatically pressed with the pressurized fluid 18.
[0030]
As the pressurized fluid 18 injected into the pressure vessel 15, a fluid such as silicone oil or water is preferably used. When silicone oil is used as the pressurized fluid 18, the temperature is set to, for example, 100 By raising one of the walls constituting the pressure vessel 15 inward or by injecting a pressurized fluid 18 into the pressure vessel 15 while applying high pressure. A predetermined pressure is applied to the outer packet body 17, whereby the pressure from the pressurized fluid 18 is uniformly applied to the upper surface and the peripheral surface of the temporary press-bonded body 11 housed in the outer packet body 17. At this time, the pressure by the hydrostatic press applied to the temporary laminate 11 is set to, for example, about 50 MPa to 150 MPa, so that each ceramic green sheet 12 is well bonded to other ceramic green sheets adjacent to the top and bottom thereof. Thus, the pressure-bonded laminate 11 ′ is formed. In addition, when using water as the pressurized fluid 18, after raising the temperature to the temperature of 50 to 60 degreeC, for example, the above-mentioned hydrostatic pressure press is performed.
[0031]
At this time, as shown in FIG. 4, a predetermined recess 19 corresponding to the boundary portion of the substrate region 10 is formed on the upper surface of the pressure-bonded laminate 11 ′, and the depth thereof is, for example, about 100 μm to 400 μm.
[0032]
(Process 4)
Next, the pressure-bonded laminate 11 ′ obtained in step 3 is taken out from the inside of the outer package 17, and divided as shown in FIG. 5 with the upper surface of the pressure-bonded laminate 11 ′ in which the recess 19 is formed facing downward. After placing on the stage 20 and then cutting the pressure-bonded laminate 11 ′ from the lower surface side (flat surface side) of the pressure-bonded laminate 11 ′ along the outer periphery of each substrate region 10 using the cutter 21. Is divided into a plurality of pieces 22 corresponding to the substrate region 10.
[0033]
The pressure-bonded laminate 11 ′ is taken out by opening the seal part of the outer package 17, and examples of the cutter 21 used for division include a long blade and a rotary blade.
[0034]
When a blade is used as the cutter 21, the pressure-bonded laminate 11 ′ is divided by pressing the blade tip against a predetermined portion (boundary portion of the substrate region 10) on the lower surface of the pressure-bonded laminate 11 ′ and cutting it as it is. The
[0035]
In this case, a depression 19 is formed on the upper surface of the pressure-bonded laminate 11 ′ at a position corresponding to the outer periphery of each substrate region 10, and the surface on which such a depression 19 is formed faces the divided stage 20 side. Since the pressure-bonded laminate 11 ′ is placed on the split stage 20, and the cutter 21 is inserted from the flat surface (lower surface) side of the pressure-bonded laminate 11 ′, the pressure-bonded laminate 11 ′ is divided. During the division, the depression 19 on the upper surface of the pressure-bonded laminate functions as an end point of the division. Therefore, “burrs” and “chips” hardly occur on the outer peripheral portion of each individual piece 22 obtained by the division, and the productivity of the multilayer ceramic electronic component can be improved.
[0036]
(Process 5)
Next, the individual pieces 22 obtained in step 4 are fired, and finally, the external electrodes 5a and 5b are deposited and formed at predetermined positions of the individual pieces 10.
[0037]
The individual pieces 22 are formed to have a substantially rectangular parallelepiped shape. For example, by firing at a temperature of 1100 ° C. to 1400 ° C., the ceramic green sheet 12 becomes the dielectric layer 2 and the conductive pattern 13 made of a conductive paste. , 14 become the first internal electrode 3 and the second internal electrode 4.
[0038]
Further, the external electrodes 5a and 5b are formed from both end surfaces of each piece 22 to both main surfaces and side surfaces located in the vicinity thereof. For example, a conductive paste mainly composed of a metal such as copper is conventionally used as a dipping method or the like. Is applied to both end faces of the individual piece 22 and the vicinity thereof, and this is baked at a high temperature, whereby a multilayer ceramic capacitor as a product is manufactured.
[0039]
In addition, this invention is not limited to the above-mentioned embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention.
[0040]
For example, in the above-described embodiment, the multilayer ceramic capacitor has been described as an example of the multilayer ceramic electronic component. However, the present invention can be applied to other multilayer ceramic electronic components such as a multilayer varistor, a multilayer chip inductor, and a multilayer wiring board. Needless to say.
[0041]
In the above-described embodiment, a plurality of temporary laminates 11 may be placed in a pressure vessel of a hydrostatic pressure press apparatus and simultaneously hydrostatic pressure pressed.
[0042]
Furthermore, in the above-described embodiment, the pressure-bonded laminate 11 ′ is fired after being divided. Alternatively, the pressure-bonded laminate 11 ′ may be fired and then divided.
[0043]
【The invention's effect】
According to the method for manufacturing a multilayer ceramic electronic component of the present invention, the pressure-bonded laminate is formed with the upper surface of the pressure-bonded laminate in which a depression is formed at a position corresponding to the outer periphery of each substrate region facing the divided stage in the isostatic pressing process. Since the pressure-bonded laminate is divided by inserting a cutter from the lower surface side of the flatly formed pressure-bonded laminate, the depression on the upper surface of the pressure-bonded laminate is formed during this division. It functions as an end point of the division, and the occurrence of “burrs”, “chips” and the like in the individual multilayer ceramic electronic parts obtained by the division is effectively prevented. Thereby, the productivity of the multilayer ceramic electronic component can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor manufactured by a manufacturing method of the present invention.
2 is a cross-sectional view of a temporary laminate 11 used in the method for producing a multilayer ceramic capacitor shown in FIG.
FIG. 3 is a schematic view showing a state in which the temporary laminated body 11 is accommodated in the outer packaging body 17 and disposed in the pressure vessel 15 of the hydrostatic pressure press device.
FIG. 4 is a schematic cross-sectional view of a pressure-bonded laminate 11 ′ obtained by pressure-bonding the temporary laminate 11 with an isostatic press.
FIG. 5 is a schematic cross-sectional view showing a process of dividing the pressure-bonded laminate 11 ′.
FIG. 6 is a cross-sectional view for explaining a conventional method of manufacturing a multilayer ceramic electronic component.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Laminated body 2 ... Dielectric layer 3 ... 1st internal electrode 4 ... 2nd internal electrode 5a, 5b ... External electrode 10 ... Substrate area | region 11 ... Temporary Laminated body 11′—Press-bonded laminated body 12—Ceramic green sheets 13, 14—Conductor pattern 15—Pressure vessel 16 of hydrostatic pressure press device—Rigid plate 17—Outer package 18— .... Pressurized fluid 19 ... depression 20 ... split stage 21 ... cutter 22 ... piece

Claims (1)

Preparing a temporary laminate having a plurality of substrate regions and a plurality of ceramic green sheets laminated via a plurality of conductor patterns corresponding to the substrate regions between the substrate regions; ,
The temporary laminate is placed on at least the flat portion of a rigid plate having a flat portion on the upper surface, and the rigid plate and the temporary laminate are accommodated in a flexible outer packaging. Degassing and sealing the outer envelope so that the inner surface of the outer envelope is in close contact with the upper surface and peripheral surface of the temporary laminate and the lower surface of the rigid plate;
The temporary laminate and the rigid plate are placed in the outer envelope and placed in a pressure vessel into which a pressurized fluid is injected, and the temporary laminate is hydrostatically pressed with the pressurized fluid, thereby pressing the temporary laminate. Forming a laminate, forming a depression corresponding to the boundary of the substrate region on the upper surface of the pressure-bonded laminate, and then removing the pressure-bonded laminate from the outer package;
The pressure-bonded laminate in which the depressions are formed is placed on the division stage with the upper surface facing downward, and then the pressure-bonded laminate is placed on the outer periphery of each substrate region from the lower surface side of the pressure-bonded laminate using a cutter. A plurality of multilayer ceramic electronic components corresponding to individual substrate regions by cutting along a plurality of multilayer ceramic electronic components.

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