JP4449544B2 - Method for forming internal electrode pattern and method for producing multilayer ceramic electronic component using the same - Google Patents

Description

  The present invention relates to a method for forming an internal electrode pattern used for a multilayer ceramic electronic component such as a multilayer ceramic capacitor, and a method for manufacturing a multilayer ceramic electronic component using the same.

Conventionally, various proposals have been made to use a metal thin film as an internal electrode of a multilayer ceramic electronic component. For example, Patent Document 1 discloses that a release layer, a metal layer, and an adhesive layer are sequentially laminated on one surface of a transfer substrate. An internal electrode transfer foil of a multilayer ceramic capacitor in which a layer and an adhesive layer have a predetermined internal electrode pattern shape is disclosed.
JP 2003-86454 A

  The conventional internal electrode transfer foil transfers a part of a continuous metal layer by a release layer and an adhesive layer provided above and below the metal layer. However, when the number of laminated layers is relatively small, for example, 100 layers or less. Even if it can be transferred with high accuracy, in the case of multi-layered up to several hundred layers, it may be transferred to unnecessary parts other than the internal electrode part when transferring to the ceramic sheet due to the difference in level due to the presence or absence of accumulated internal electrodes. In addition, there is a problem that a portion that cannot be transferred to a desired shape occurs due to imperfect transfer.

  In addition, there is a method of transferring a metal thin film to an internal electrode shape by a method such as etching or photolithography in advance, but in this case, many processes are required and mass production is required because expensive equipment is required. It was inferior to.

  The present invention relates to a method for forming an internal electrode pattern capable of accurately transferring an internal electrode to a desired shape even in the case of, for example, several hundreds of layers and multi-layers, and manufacture of a multilayer ceramic electronic component using the same. It is intended to provide a method.

In order to achieve this object, the present invention provides a method for forming an internal electrode pattern of a multilayer ceramic electronic component, comprising: a metal thin film formed by an assembly of columnar bodies and having a shape viewed from the surface divided into fine areas by cracks. A first step of forming on the first support, a second step of forming a resin layer on the second support in a shape corresponding to the non-formed portion of the internal electrode, and the first support A third step in which the metal thin film and the resin layer on the second support are overlapped so that the metal thin film and the resin layer face each other and pressed together with the support, and after pressurization in the third step An internal electrode pattern forming method comprising a fourth step of peeling off the second support and removing a metal thin film on the non-formed portion of the internal electrode together with the resin layer, wherein the metal thin film is accurately formed in a desired shape. Can transfer well.

  In addition, by using a metal thin film that is formed by a collection of columnar bodies and whose shape viewed from the surface is divided into fine areas by cracks, it is possible to reduce occurrence of unnecessary transfer portions and insufficient transfer portions. The internal electrode pattern can be formed with higher accuracy.

  Furthermore, by producing a multilayer body using the above internal electrode pattern forming method, cutting into individual pieces and firing to obtain a multilayer ceramic electronic component, for example, a multilayer ceramic with less variation in capacitance and less short-circuit defects Electronic parts can be produced.

  The internal electrode pattern forming method according to the present invention uses a resin layer corresponding to the internal electrode non-formed portion to remove the metal thin film corresponding to the non-formed portion, and removes the internal electrode pattern of the metal thin film by a highly productive method. Since the multilayer ceramic electronic component is manufactured using this, the internal electrode can be transferred with high accuracy even in the case of a multi-layer such as several hundred layers. Short circuit failure can be suppressed.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings, taking a multilayer ceramic capacitor as an example.

  FIG. 7 is a partially cutaway perspective view of the multilayer ceramic capacitor 41, in which the dielectric layers 42 and the internal electrodes 43 are alternately stacked to form a multilayer body, and the end surfaces of the internal electrodes 43 are opposed to the multilayer body. They are laminated so as to be alternately exposed on both end faces, and are alternately connected to a pair of external electrodes 44 formed on both end faces of the laminate.

A method for manufacturing such a multilayer ceramic capacitor will be described below. First, ceramic powder that contains barium titanate as the main component and is mixed with a ceramic raw material powder containing rare earth oxides and additives such as SiO ₂ , MgO, and MnO _2, and calcined and ground as necessary. Create a body.

  The ceramic powder is mixed with a binder such as polyvinyl butyral resin or acrylic resin, a plasticizer such as phthalate ester, and a solvent such as butyl acetate to produce a ceramic slurry.

  The ceramic slurry is coated on a film 11 such as polyethylene terephthalate (hereinafter abbreviated as PET) using a method such as a doctor blade as shown in FIG. This ceramic sheet forms a dielectric layer by firing.

  Separately, a Ni metal thin film 22 is formed on the first support 21 such as a PET film or a polyimide film by vapor deposition using a vapor deposition apparatus schematically shown in FIG. The first support 21 is supplied from the unwinding roll 29, the Ni metal thin film 22 is deposited while being cooled by the cooling drum 28, and the first support 21 supplied with the Ni metal thin film 22 is applied to the take-up roll 30. It is wound up.

  Note that the vacuum chamber 23 of the vapor deposition apparatus in FIG. 2 is depressurized by an exhaust pipe 31 attached to the lower portion of the vacuum chamber 23.

Here, the Ni metal thin film 22 is formed by the Ni vapor 27 evaporated from the deposited metal (Ni) 26, and at the same time, the Ar gas 24 is supplied from the gas nozzle 25 toward the portion where the Ni metal thin film is formed, and the vacuum is applied. The degree of vacuum of the tank 23 was 8 × 10 ⁻² Pa under Ar gas supply, and the feed rate of the support 21 was 20 m / min. The Ni metal thin film 22 thus formed has a thickness of 0.5 μm. According to the observation result of the cross section, the Ni metal thin film 22 is formed by a collection of fine columnar bodies continuous in the vertical direction. The shape seen from the surface of 22 had a structure divided into fine areas by cracks.

  Further, a resin paste containing a polyvinyl butyral resin and a plasticizer is prepared, and a pattern shape corresponding to a portion where an internal electrode is not formed on the second support 32 as shown in FIG. 3 using a method such as gravure printing. A first resin layer 33 was formed.

  Next, as shown in FIG. 4, the Ni metal thin film 22 formed on the first support 21 and the patterned resin layer corresponding to the internal electrode non-formation portion formed on the second support 32. 33 are stacked so as to face each other, and after pressing from the supports 21 and 32 side, the support 32 is peeled off. As shown in FIG. 5, a patterned Ni metal thin film 22 corresponding to the internal electrode non-formation portion is formed. The internal electrode pattern 34 was produced by removing together with the resin layer 33 on the support 32. The metal thin film 22 becomes an internal electrode by firing. When removing the internal electrode non-forming portion, the Ni metal thin film is formed by a collection of fine columnar bodies whose cross sections are continuous in the vertical direction, and the shape viewed from the surface of the Ni metal thin film is divided into fine areas by cracks. Therefore, the internal electrode non-formed part can be easily removed, and the internal electrode pattern after removing the non-formed part is not removed and there is no part that has been removed or removed too much. A shape was obtained.

  The internal electrode pattern 34 thus produced and the ceramic sheet 12 are alternately 300 layers via an adhesive layer (not shown) separately formed in advance on a PET film with a thickness of 0.01 μm to 0.5 μm. The laminated body 35 as shown in FIG. 6 was produced by laminating, cut into predetermined dimensions so as to have a size of 3.2 mm × 1.6 mm after firing, and fired.

This adhesive layer contains polyvinyl butyral resin, an organic substance such as a plasticizer, and barium titanate having a specific surface area of 20 m ² / g, and has a bonding property between the dielectric layer and the internal electrode during the firing process of the laminate. And can prevent the occurrence of structural defects such as delamination.

  In addition to barium titanate, the ceramic powder to be included in the adhesive layer can be obtained by using magnesium oxide and aluminum oxide, and these three types of ceramic powders may be used in combination. In particular, barium titanate is a metal thin film. It has a function of entering the cracks formed on the surface of the metal and connecting the dielectric layers above and below the internal electrode made of a metal thin film, and has a greater effect of suppressing internal structural defects than the other two types of ceramic powder. Furthermore, since barium titanate is the same as the main component of the dielectric layer, even if the amount added to the adhesive layer is increased, the influence on characteristics such as capacitance is small.

Any of the above ceramic powders preferably has a specific surface area of 10 m ² / g or more.

  Thereafter, external electrodes were formed on both end faces where the internal electrodes were exposed, and a sample for measuring capacitance and short-circuit rate (sample number 1) was obtained.

  Regarding the electrostatic capacity, 100 samples were measured in a constant temperature bath of 20 ° C. at a frequency of 1 kHz and an input signal level of 1.0 Vrms, and the electrostatic capacity variation was evaluated by a difference R between the maximum value and the minimum value.

With respect to the short-circuit rate, the resistance value of the 100 samples after the capacitance measurement was measured using an insulation resistance meter, and the number of resistance values of 10 ³ Ω or less was expressed as a percentage to obtain the short-circuit rate.

  Further, as a comparative example by the conventional method, a peeling layer is formed in the shape of an internal electrode pattern on a PET film by the method described in Japanese Patent Application Laid-Open No. 2003-86454, and Ar gas is different from the first embodiment on this. The Ni metal thin film 22 was formed by the same method as that of the first embodiment except that is not supplied.

  When the cross-sectional structure of the Ni metal thin film 22 was observed, the vertical shape of the Ni vapor deposition film was not a continuous columnar structure, but a structure consisting of large columnar bodies intermittent in the vertical direction, and the surface structure was cracked. It was a continuous structure with little or no.

  An adhesive layer having an internal electrode pattern shape was formed on the Ni metal thin film 22, and 300 layers were laminated while being transferred to a ceramic sheet in the same manner as in the first embodiment.

  In this lamination process, the internal electrode pattern is partially formed in an insufficient shape, and there are many portions where the metal thin film is transferred to the periphery of the predetermined internal electrode pattern shape until it reaches the non-formed portion. It was.

  The laminated body 35 after being laminated is cut in a predetermined size so as to be 3.2 mm × 1.6 mm after firing in the same manner as in the first embodiment, fired, and formed with external electrodes. The same measurement was performed using the measurement sample (sample number 2) of the comparative example.

  For the multilayer ceramic capacitor sample numbers 1 and 2, the results of the measurement of the average value of capacitance and the variation in capacitance and the short-circuit rate are shown in Table 1 below.

  The variation in capacitance is expressed as an R value that is the difference between the maximum value and the minimum value of the capacitance.

  As is clear from Table 1, Sample No. 1 according to an embodiment of the present invention has a small R value indicating a variation in capacitance of 0.5 μF and a short rate of 0.1%. On the other hand, in the sample number 2 of the comparative example, the R value is 1.8 μF, the variation in capacitance is large, and the short-circuit rate is as large as 35%. This is because the transfer of the metal thin film 22 according to the conventional method of Sample No. 2 has almost no cracks on the surface of the metal thin film 22, and the metal thin film 22 is formed as a continuous structure, so that the transfer is performed up to a portion where transfer is not desired. This leads to variations in capacitance and an increase in the short-circuit rate.

  In the present embodiment, the metal thin film 22 is patterned into an internal electrode shape by removing the metal thin film 22 in the internal electrode non-formed portion using the patterned resin layer 33 corresponding to the internal electrode non-formed portion. This is because when the metal thin film is transferred to the internal electrode pattern shape on the ceramic sheet through the resin layer formed in the internal electrode pattern shape, the resin layer is not formed depending on the adhesion of the ceramic sheet, that is, the internal electrode This is because the non-formed portion may be transferred onto the ceramic sheet.

  In order to avoid the above problems, in the present invention, the metal thin film 22 previously patterned into the shape of the internal electrode is transferred onto the ceramic sheet 12.

  In the embodiment of the present invention, the ceramic sheet 12 formed on the film 11 such as PET is used. However, the present invention is not limited to this. For example, ceramic powder and polyethylene having a molecular weight of 40,000 or more are used. It is also possible to use a ceramic sheet obtained by kneading, etc., forming into a sheet shape, and further biaxially stretching.

  In this case, since the ceramic sheet containing polyethylene has low adhesiveness, even if the metal thin film is transferred to the internal electrode pattern shape on the ceramic sheet through the resin layer formed in the internal electrode pattern shape as described above. Good.

  The internal electrode pattern forming method according to the present invention is highly mass-productive in that the ceramic electronic component manufacturing method uses a resin layer corresponding to the internal electrode non-formed portion to remove the metal thin film corresponding to the non-formed portion. The internal electrode pattern of the metal thin film is formed by the method, and the multilayer ceramic electronic component is manufactured using the metal thin film pattern. Therefore, the internal electrode can be accurately transferred even in the case of multi-layers such as several hundred layers. This is useful for manufacturing parts.

Sectional drawing of the ceramic sheet formed on the film in one embodiment of this invention Schematic diagram of the deposition equipment Sectional drawing of the resin layer formed on the said 2nd support body Sectional drawing for demonstrating the method to form the internal electrode pattern Sectional drawing for demonstrating the method to form the internal electrode pattern Cross section of the same laminate Partial cutaway perspective view of the same multilayer ceramic capacitor

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 PET film 12 Ceramic sheet 21 1st support body 22 Metal thin film 23 Vacuum tank 24 Ar gas 25 Gas nozzle 26 Deposition metal 27 Ni vapor 28 Cooling drum 29 Unwinding roll 30 Winding roll 31 Exhaust pipe 32 2nd support body 33 Resin layer 34 Internal electrode pattern 35 Multilayer body 41 Multilayer ceramic capacitor 42 Dielectric layer 43 Internal electrode 44 External electrode

Claims (4)

A method for forming an internal electrode pattern of a multilayer ceramic electronic component, comprising : forming a metal thin film formed by a collection of columnar bodies and having a shape viewed from the surface divided into fine areas by cracks on a first support; The second step of forming a resin layer on the second support in a shape corresponding to the non-formed portion of the internal electrode, the metal thin film on the first support, and the second support A third step of superposing the upper resin layer with the metal thin film and the resin layer facing each other and pressurizing the whole support; and peeling off the second support after pressurizing the third step; A method for forming an internal electrode pattern, comprising a fourth step of removing the metal thin film on the non-formed portion of the internal electrode together with the resin layer. In a method for manufacturing a ceramic electronic component including a step of laminating ceramic sheets and internal electrodes alternately, a first metal thin film formed by a collection of columnar bodies and having a shape viewed from the surface divided into fine areas by cracks is first. A first step of forming a resin layer on the second support, a second step of forming a resin layer on the second support in a shape corresponding to the non-formed portion of the internal electrode, and the first support A third step in which the metal thin film and the resin layer on the second support are overlapped so that the metal thin film and the resin layer face each other and pressed together with the support; and after the pressurization in the third step, the first A fourth step of peeling the support of 2 and removing the metal thin film of the non-formed portion of the internal electrode together with the resin layer to form an internal electrode pattern, a ceramic sheet and a metal thin film having the internal electrode pattern formed thereon, Alternately stacked The a fifth step, a sixth step of the manufacturing method of a multilayer ceramic electronic component including a firing cutting the laminate to produce a laminate Te. 3. The multilayer ceramic according to claim 2 , wherein the fifth step of laminating the metal thin film on which the internal electrode pattern is formed and the ceramic sheet is laminated with a second resin layer interposed at an interface between the metal thin film and the ceramic sheet. Manufacturing method of electronic components. The method for producing a multilayer ceramic electronic component according to claim 3 , wherein the second resin layer contains one or more ceramic powders selected from barium titanate, magnesium oxide, and aluminum oxide.

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