JP2004221304A - Method for manufacturing electronic parts having internal electrode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing electronic parts having an internal electrode such as a laminate ceramic capacitor capable of effectively suppressing the deterioration of an electrostatic capacity. <P>SOLUTION: This method for manufacturing electronic parts having an internal electrode comprises a process for burning a green chip formed by laminating a green sheet to which an electrode layer formed with a predetermined pattern by a film thinning method is bonded with another green sheet. The electrode layer containing alloy having nickel (Ni) and tungsten (W) where the content of those respective components is Ni: 80 to 100 mol.% (excluding 100 mol.%) and W: 0 to 20 mol.% (excluding 0 mol.%) with thickness ranging from 0.1 to 1 μm is used to burn the green chip at temperatures ranging from 1,000 to 1,300 °C in an atmosphere having oxygen partial pressures of 10<SP>-14</SP>to 10<SP>-8</SP>Pa. Thus, it is possible to provide electronic parts having an internal electrode such as a laminate ceramic capacitor capable of effectively suppressing the deterioration of an electrostatic capacity. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０１２６】
【表２】

【０１２７】
【表３】

【０１２８】
【表４】

【０１２９】
【表５】

【０１３０】
【表６】

【０１３１】
【表７】

【０１３２】
表１に示すように、ＮｉとＷの含有量（単位はｍｏｌ％）に関し、Ｎｉ：Ｗ＝１００：０であると、静電容量の低下を抑制できなかった。Ｎｉ：Ｗ＝７５：２５であると、静電容量の低下は抑制できたが、抵抗率が増大し、ｔａｎδが増加した。これに対し、Ｎｉ：Ｗ＝８０〜１００（ただし１００は除く）：０〜２０（ただし０は除く）であると、抵抗率とｔａｎδの増加を引き起こすことなく、静電容量の低下を抑制できることが確認された。
【０１３３】
表２に示すように、合金薄膜の厚みに関し、合金膜厚み＝０．０５μｍであると、電極層が球状化してしまい、静電容量の低下を抑制できなかった。これに対し、合金膜厚み＝０．１〜１μｍであると、電極層の球状化を生じることなく、静電容量の低下を抑制できることが確認された。
【０１３４】
表３に示すように、焼成時の焼成温度に関し、焼成温度＝９５０℃であると、誘電体層が焼結不足となり、静電容量の低下を抑制できなかった。焼成温度＝１３５０℃であると、電極層が球状化するとともに酸化し、誘電体層へ拡散してしまい、静電容量の低下を抑制できなかった。これに対し、焼成温度＝１０００〜１３００℃であると、焼結不足や電極層の球状化や電極層の誘電体層への拡散を生じることもなく、静電容量の低下を抑制できることが確認された。
【０１３５】
表４に示すように、焼成時の酸素分圧に関し、酸素分圧＝１０^−１５ Ｐａであると、電極層が球状化するとともに途切れ、静電容量の低下を抑制できなかった。酸素分圧＝１０^−７Ｐａであると、電極層が球状化するとともに酸化し、誘電体層へ拡散してしまい、静電容量の低下を抑制できなかった。これに対し、酸素分圧＝１０^−１４ 〜１０^−８Ｐａであると、電極層の球状化，途切れや電極層の誘電体層への拡散を生じることもなく、静電容量の低下を抑制できることが確認された。
【０１３６】
表５〜７に示すように、アニール時の保持温度、酸素分圧および温度保持時間に関し、保持温度＝５５０℃、酸素分圧＝１０^−３Ｐａおよび温度保持時間＝３〜４時間であると、ｔａｎδが大きくなる傾向にあるが、いずれも許容範囲内であった。保持温度＝９５０℃、酸素分圧＝１０^２ Ｐａおよび温度保持時間＝２１時間であると、静電容量の低下が進む傾向にあるが、いずれも許容範囲内であった。これに対し、保持温度＝６００〜９００℃、酸素分圧＝１０^−２〜１０^１Ｐａおよび温度保持時間＝８〜２０時間であると、ｔａｎδも低く抑えつつ、静電容量の低下を抑制できることが確認された。
【０１３７】
【発明の効果】
以上説明してきたように、本発明によれば、静電容量の低下を効果的に抑制することができる積層セラミックコンデンサなどの内部電極を持つ電子部品の製造方法を提供することができる。
【図面の簡単な説明】
【図１】図１は本発明の一実施形態に係る積層セラミックコンデンサの概略断面図である。
【図２】図２（Ａ）〜図２（Ｃ）は電極層の転写方法を示す要部断面図である。
【図３】図３（Ａ）〜図３（Ｃ）は図２の続きの工程を示す要部断面図である。
【図４】図４（Ａ）〜図４（Ｃ）は電極層が接着されたグリーンシートの積層方法を示す要部断面図である。
【図５】図５（Ａ）〜図５（Ｃ）は図４の続きの工程を示す電極層が接着されたグリーンシートの積層方法を示す要部断面図である。
【図６】図６（Ａ）〜図６（Ｃ）は図５の続きの工程を示す要部断面図である。
【図７】図７は本発明の一実施例に係る合金粉末のＸ線回折チャートである。
【符号の説明】
２… 積層セラミックコンデンサ
４… コンデンサ素体
６，８… 端子電極
１０… 誘電体層
１０ａ… グリーンシート
１２… 内部電極層
１２ａ… 電極層
２０… キャリアシート（第１支持シート）
２２… 剥離層
２６… キャリアシート（第３支持シート）
２８… 接着層
３０… キャリアシート（第２支持シート）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing an electronic component having internal electrodes such as a multilayer ceramic capacitor.
[0002]
[Prior art]
A multilayer ceramic capacitor as an example of an electronic component having an internal electrode has an element body having a multilayer structure in which a plurality of dielectric layers and internal electrode layers are alternately arranged, and a pair of external elements formed at both ends of the element body. It is known to be composed of terminal electrodes.
[0003]
In this multilayer ceramic capacitor, first, a required number of dielectric layers before firing and internal electrode layers before firing are alternately laminated in a required number to produce an element body before firing. It is manufactured by forming a pair of external terminal electrodes at both ends.
[0004]
As the dielectric layer before firing, a ceramic green sheet is used, and as the internal electrode layer before firing, an internal electrode paste or a metal thin film having a predetermined pattern is used.
[0005]
The ceramic green sheet can be manufactured by a sheet method, a stretching method, or the like. The sheet method is a method in which a dielectric paint containing a dielectric powder, a binder, a plasticizer, an organic solvent, and the like is coated on a carrier sheet such as PET using a doctor blade method or the like, and is heated and dried to manufacture. . The stretching method is a method of biaxially stretching a film-shaped molded product obtained by extruding a dielectric suspension in which a dielectric powder and a binder are mixed in a solvent.
[0006]
The internal electrode paste having a predetermined pattern is manufactured by a printing method. The printing method is a method in which a conductive material containing a metal such as Pd, Ag-Pd, and Ni, and a conductive paint containing a binder, an organic solvent, and the like are applied and formed on a ceramic green sheet in a predetermined pattern. The metal thin film having a predetermined pattern is manufactured by a thin film method such as sputtering.
[0007]
As described above, when manufacturing the multilayer ceramic capacitor, the dielectric layer before firing and the internal electrode layer before firing are simultaneously fired. Therefore, the conductive material contained in the internal electrode layer before firing must have a melting point higher than the sintering temperature of the dielectric powder contained in the dielectric layer before firing, not react with the dielectric powder, It is required not to diffuse into the body layer.
[0008]
Conventionally, in order to satisfy these requirements, a noble metal such as Pt or Pd has been used as a conductive material included in the internal electrode layer before firing. However, the noble metal itself is expensive, and as a result, the resulting multilayer ceramic capacitor has a disadvantage that the cost is high. Therefore, conventionally, the sintering temperature of the dielectric powder was lowered to 900 to 1100 ° C., and an Ag-Pd alloy was used as a conductive material included in the internal electrode layer before firing, or an inexpensive base metal such as Ni was used. Is widely known.
[0009]
By the way, in recent years, with the miniaturization of various electronic devices, multilayer ceramic capacitors mounted inside the electronic devices have been reduced in size and increased in capacity. In order to reduce the size and increase the capacity of the multilayer ceramic capacitor, it is required to laminate not only dielectric layers but also internal electrode layers that are thin and have few defects.
[0010]
However, when the case where Ni is used as the conductive material included in the internal electrode layer before firing is exemplified, the melting point of Ni is lower than that of the dielectric powder included in the dielectric layer before firing. For this reason, when these were co-fired, a large difference occurred between the two sintering temperatures. If there is a large difference in the sintering temperature, sintering at a high temperature may cause cracking or peeling of the internal electrode layer, while sintering at a low temperature may cause poor firing of the dielectric powder.
[0011]
Also, if the thickness of the internal electrode layer before firing is too thin, the Ni particles contained in the conductive material become spherical due to grain growth during firing in a reducing atmosphere, and adjacent Ni particles connected before firing are connected. Voids are formed at arbitrary locations due to an interval between them, and as a result, it becomes difficult to continuously form internal electrode layers after firing. When the internal electrode layers are not continuous after firing, there is a problem that the capacitance of the multilayer ceramic capacitor is reduced.
[0012]
On the other hand, Patent Documents 1 and 2 disclose a technique in which an alloy of Ni and W is used as a conductive material constituting an internal electrode layer after firing. According to the techniques described in Patent Documents 1 and 2, spheroidization due to grain growth of alloy particles contained in the conductive material seems to be relatively prevented. However, in these techniques, although not explicitly described, it is considered that after baking at a normal oxygen partial pressure, annealing is performed at a relatively high temperature in a short time, so that W is easily oxidized and finally obtained. There is a strong possibility that the capacitance of the resulting multilayer ceramic capacitor will decrease.
[0013]
[Patent Document 1] JP-A-2000-169923
[Patent Document 2] Japanese Patent Application Laid-Open No. 2002-60877
[0014]
[Problems to be solved by the invention]
An object of the present invention is to provide a method of manufacturing an electronic component having an internal electrode such as a multilayer ceramic capacitor capable of effectively suppressing a decrease in capacitance.
[0015]
[Means for Solving the Problems]
To achieve the above object, according to the present invention,
A method of manufacturing an electronic component having internal electrodes, comprising a step of firing a green chip formed by laminating a green sheet to which an electrode layer formed in a predetermined pattern by a thin film method is adhered together with another green sheet. ,
It contains nickel (Ni) and tungsten (W), and the content of each component is as follows: Ni: 80 to 100 mol% (excluding 100 mol%), W: 0 to 20 mol% (however, 0 mol) % Excluding), using an electrode layer having a thickness of 0.1 to 1 μm,
10^-14-10^-8A method for producing an electronic component having internal electrodes, characterized by firing at a temperature of 1000 to 1300 ° C. in an atmosphere having an oxygen partial pressure of Pa.
[0016]
This invention
A step of forming an electrode layer in a predetermined pattern by a thin film method on the surface of the release layer containing the dielectric,
A step of forming an adhesive layer by a transfer method on the surface of the electrode layer or the surface of a green sheet containing substantially the same dielectric as the dielectric contained in the release layer,
Pressing the adhesive layer against the surface of the green sheet or the surface of the electrode layer, and bonding the electrode layer to the green sheet;
A step of laminating the green sheet to which the electrode layer is adhered together with other green sheets to form a green chip,
And a step of baking the green chip.
[0017]
Preferably, after the step of firing the green chip, 10^-2A step of annealing at a temperature of 600 to 900 ° C. for 4 to 20 hours in an atmosphere having an oxygen partial pressure of 10 to 10 Pa.
[0018]
Preferably, in the X-ray diffraction chart, the peak intensity of the diffraction line on the crystal plane (111) plane is I (111), the peak intensity of the diffraction line on the crystal plane (200) plane is I (200), and the crystal plane ( Assuming that the peak intensity of the diffraction line on the (220) plane is I (220), the relations of (I (111) / I (200)) ≧ 3 and (I (111) / I (220)) ≧ 3 are satisfied. An electrode layer containing an alloy having a main surface is used.
[0019]
Preferably, an electrode layer containing an alloy having a crystallite size of 10 to 100 nm is used.
[0020]
In the present invention, the electrode layer is formed on the surface of the release layer by a thin film method. The thin film method is not particularly limited, but examples include a sputtering method, a vacuum evaporation method, and a CVD method. Especially, a sputtering method is preferable. When the electrode layer is formed by the thin film method, the binder and the plasticizer component are evaporated under vacuum, and the peeling layer is damaged by sputtered particles and evaporated particles.
However, this works in the direction of weakening the strength of the release layer, so that the electrode layer is conveniently transferred to the surface of the green sheet.
[0021]
In the present invention, the material and production method of the green sheet are not particularly limited, and a ceramic green sheet formed by a doctor blade method, a porous ceramic green sheet obtained by biaxially stretching an extruded film, and the like. It may be.
[0022]
The release layer includes a dielectric substantially the same as the dielectric constituting the green sheet. For this reason, even if the release layer adheres and remains on the surface of the electrode layer, the remaining release layer does not pose a problem. Because, the remaining release layer is sufficiently thin compared to the green sheet, and furthermore, since it contains the same dielectric as the dielectric constituting the green sheet, even if it is laminated with the green sheet and fired simultaneously, This is because it becomes a part of the dielectric layer like the green sheet.
[0023]
Preferably, the release layer includes a binder resin substantially the same as the binder resin included in the green sheet. Preferably, the adhesive layer includes a binder resin substantially the same as the binder resin included in the green sheet. Preferably, the electrode layer includes substantially the same binder resin as the binder resin included in the green sheet. Preferably, the binder resin partially contains a butyral-based resin, or is composed of only a butyral-based resin.
[0024]
The release layer, the adhesive layer, the electrode layer, and the green sheet may contain a plasticizer together with the binder resin, and the plasticizer is preferably contained in an amount of 25 to 100 parts by mass with respect to 100 parts by mass of the binder resin. Preferably, the content ratio of the binder to the dielectric contained in the release layer is equal to or lower than the content ratio of the binder to the dielectric contained in the green sheet. Preferably, the content ratio of the plasticizer to the dielectric contained in the release layer is equal to or higher than the content ratio of the plasticizer to the dielectric contained in the green sheet. Preferably, the content ratio of the release agent to the dielectric contained in the release layer is higher than the content ratio of the release agent to the dielectric contained in the green sheet.
[0025]
Preferably, the thickness of the green sheet is 3 μm or less. Preferably, the thickness of the release layer is equal to or less than the thickness of the electrode layer. The thickness of the release layer is set to preferably 60% or less of the thickness of the electrode layer, more preferably 30% or less. The lower limit of the thickness of the release layer is determined by the particle size of the dielectric material that can be used for the release layer, and is preferably 0.1 to 0.2 μm. Preferably, the pressure for bonding the electrode layer to the surface of the green sheet is 0.2 to 15 MPa. The temperature during pressurization is preferably about 40 to 100 ° C.
[0026]
Since W has a higher melting point than Ni, this raises the sintering temperature of the conductive material and approaches the sintering temperature of the dielectric powder. On the other hand, since W is more easily oxidized than Ni, W is oxidized under normal Ni baking conditions. Oxidation of W causes a decrease in capacitance. In the present invention, the pre-firing internal electrode layer containing the Ni—W alloy having the specific composition is fired in an atmosphere in which the oxygen partial pressure is lower than normal Ni firing conditions. Thereby, while increasing the sintering start temperature of the Ni—W alloy that constitutes the internal electrode layer, spheroidization due to grain growth is suppressed, and the internal electrode is continuously formed. Can be suppressed. In the present invention, preferably, after the baking, annealing is performed at a temperature lower than a normal Ni annealing condition for a longer time. By this annealing treatment, re-oxidation of the dielectric layer is achieved, semiconductor formation is prevented, and high insulation resistance can be obtained.
[0027]
According to the present invention, it is produced by any one of the above methods,
An electronic component having an internal electrode is provided.
[0028]
According to the present invention, it is possible to provide an electronic component having internal electrodes such as a multilayer ceramic capacitor in which a decrease in capacitance is effectively suppressed.
[0029]
Although the electronic component having the internal electrode is not particularly limited, a multilayer ceramic capacitor, a piezoelectric element, a chip inductor, a chip varistor, a chip thermistor, a chip resistor, and other surface mount (SMD) chip type electronic components are exemplified.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described based on embodiments shown in the drawings. put it here,
FIG. 1 is a schematic sectional view of a multilayer ceramic capacitor according to one embodiment of the present invention,
2 (A) to 2 (C) and FIGS. 3 (A) to 3 (C) are cross-sectional views of main parts showing a method of transferring an electrode layer.
FIGS. 4A to 4C, FIGS. 5A to 5C, and FIGS. 6A to 6C show a method of laminating a green sheet to which an electrode layer is adhered. Sectional view,
FIG. 7 is an X-ray diffraction chart of the alloy powder according to one embodiment of the present invention.
[0031]
First, an overall configuration of a multilayer ceramic capacitor will be described as one embodiment of an electronic component manufactured by the method according to the present invention.
[0032]
As shown in FIG. 1, the multilayer ceramic capacitor 2 according to the present embodiment has a capacitor body 4, a first terminal electrode 6, and a second terminal electrode 8. The capacitor body 4 has a dielectric layer 10 and an internal electrode layer 12, and the internal electrode layers 12 are alternately stacked between the dielectric layers 10. One of the alternately laminated internal electrode layers 12 is electrically connected to the inside of the first terminal electrode 6 formed outside the first end 4 a of the capacitor body 4. The other alternately laminated internal electrode layers 12 are electrically connected to the inside of the second terminal electrode 8 formed outside the second end 4 b of the capacitor body 4.
[0033]
In this embodiment, the internal electrode layer 12 is formed by transferring the electrode layer 12a to the ceramic green sheet 10a as shown in FIGS. Although it is made of a material, its thickness is larger than that of the electrode layer 12a by the amount of shrinkage in the horizontal direction due to baking.
[0034]
The material of the dielectric layer 10 is not particularly limited, and is made of a dielectric material such as calcium titanate, strontium titanate, and / or barium titanate. The thickness of each dielectric layer 10 is not particularly limited, but is generally several μm to several hundred μm. In particular, in the present embodiment, the thickness is reduced to preferably 5 μm or less, more preferably 3 μm or less.
[0035]
Although the material of the terminal electrodes 6 and 8 is not particularly limited, copper, a copper alloy, nickel, a nickel alloy or the like is usually used, but silver or an alloy of silver and palladium can also be used. The thickness of the terminal electrodes 6 and 8 is not particularly limited, but is usually about 10 to 50 μm.
[0036]
The shape and size of the multilayer ceramic capacitor 2 may be appropriately determined according to the purpose and use. When the multilayer ceramic capacitor 2 has a rectangular parallelepiped shape, it is usually vertical (0.6 to 5.6 mm, preferably 0.6 to 3.2 mm) × horizontal (0.3 to 5.0 mm, preferably 0.3 to 5.0 mm). 1.6 mm) × thickness (0.1 to 1.9 mm, preferably 0.3 to 1.6 mm).
[0037]
Next, an example of a method for manufacturing the multilayer ceramic capacitor 2 according to the present embodiment will be described.
[0038]
(1) First, a dielectric paste is prepared in order to manufacture a ceramic green sheet that will constitute the dielectric layer 10 shown in FIG. 1 after firing.
[0039]
The dielectric paste is usually composed of an organic solvent-based paste or an aqueous paste obtained by kneading a dielectric material and an organic vehicle.
[0040]
As the dielectric material, various compounds that can be used as composite oxides and oxides, for example, carbonates, nitrates, hydroxides, organometallic compounds, and the like can be appropriately selected and used as a mixture. The dielectric material is usually used as a powder having an average particle size of about 0.1 to 3.0 μm. In order to form an extremely thin green sheet, it is desirable to use a powder finer than the green sheet thickness.
[0041]
The organic vehicle is obtained by dissolving a binder in an organic solvent. The binder used for the organic vehicle is not particularly limited, and various ordinary binders such as ethyl cellulose, polyvinyl butyral, and acrylic resin are used, but butyral-based resins such as polyvinyl butyral are preferably used.
[0042]
The organic solvent used for the organic vehicle is not particularly limited, and organic solvents such as terpineol, butyl carbitol, acetone, and toluene are used. The vehicle in the aqueous paste is obtained by dissolving a water-soluble binder in water. The water-soluble binder is not particularly limited, and polyvinyl alcohol, methyl cellulose, hydroxyethyl cellulose, water-soluble acrylic resin, emulsion, and the like are used. The content of each component in the dielectric paste is not particularly limited, and may be a usual content, for example, about 1 to 5% by mass of a binder and about 10 to 50% by mass of a solvent (or water).
[0043]
The dielectric paste may contain additives selected from various dispersants, plasticizers, dielectrics, glass frit, insulators, and the like, if necessary. However, the total content thereof is desirably 10% by mass or less. When a butyral resin is used as the binder resin, the content of the plasticizer is preferably 25 to 100 parts by mass with respect to 100 parts by mass of the binder resin. If the amount of the plasticizer is too small, the green sheet tends to become brittle, and if the amount is too large, the plasticizer oozes out and handling is difficult.
[0044]
Then, using this dielectric paste, a doctor blade method or the like is used, as shown in FIG. 3A, on a carrier sheet 30 as a second support sheet, preferably 0.5 to 30 μm, more preferably 0 to 30 μm. The green sheet 10a is formed with a thickness of about 0.5 to 10 μm. The green sheet 10a is dried after being formed on the carrier sheet 30. The drying temperature of the green sheet 10a is preferably 50 to 100C, and the drying time is preferably 1 to 5 minutes.
[0045]
(2) Separately from the carrier sheet 30, as shown in FIG. 2A, a carrier sheet 20 as a first support sheet is prepared, a release layer 22 is formed thereon, and An electrode layer 12a having a predetermined pattern is formed.
[0046]
As the carrier sheets 20 and 30, for example, a PET film or the like is used, and it is preferable that the carrier sheets 20 and 30 are coated with silicon or the like in order to improve releasability. The thickness of these carrier sheets 20 and 30 is not particularly limited, but is preferably 5 to 100 μm. The thicknesses of the carrier sheets 20 and 30 may be the same or different.
[0047]
The release layer 22 preferably contains the same dielectric particles as the dielectric constituting the green sheet 10a shown in FIG. The release layer 22 contains a binder, a plasticizer, and (a release agent) in addition to the dielectric particles. The particle size of the dielectric particles may be the same as the particle size of the dielectric particles contained in the green sheet, but is preferably smaller.
[0048]
The thickness t2 of the release layer 22 is preferably not more than the thickness t1 of the electrode layer 12a, and is preferably not more than 60%, more preferably not more than 30% of the thickness t1 of the electrode layer 12a.
[0049]
The method for applying the release layer 22 is not particularly limited. However, since it is necessary to form the release layer 22 in an extremely thin manner, an application method using, for example, a wire bar coater is preferable. The thickness of the release layer can be adjusted by selecting wire bar coaters having different wire diameters. That is, in order to reduce the coating thickness of the release layer, a wire having a small wire diameter may be selected, and in order to form a thick layer, a wire having a large wire diameter may be selected. The release layer 22 is dried after the application. The drying temperature is preferably from 50 to 100 ° C., and the drying time is preferably from 1 to 10 minutes.
[0050]
The binder for the release layer 22 is made of, for example, an acrylic resin, polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol, polyolefin, polyurethane, polystyrene, or an organic material composed of a copolymer thereof, or an emulsion. The binder included in the release layer 22 may be the same as or different from the binder included in the green sheet 10a, but is preferably the same.
[0051]
Examples of the plasticizer for the release layer 22 include, but are not particularly limited to, phthalic acid esters, adipic acid, phosphoric acid esters, and glycols. The plasticizer contained in the release layer 22 may be the same as or different from the plasticizer contained in the green sheet 10a.
[0052]
The release agent for the release layer 22 is not particularly limited, and examples thereof include paraffin, wax, and silicone oil. The release agent contained in the release layer 22 may be the same as or different from the release agent contained in the green sheet 10a.
[0053]
The binder is contained in the release layer 22 in an amount of preferably 2.5 to 200 parts by mass, more preferably 5 to 30 parts by mass, and particularly preferably about 8 to 30 parts by mass with respect to 100 parts by mass of the dielectric particles. .
[0054]
The plasticizer is preferably contained in the release layer 22 in an amount of 0 to 200 parts by mass, preferably 20 to 200 parts by mass, and more preferably 50 to 100 parts by mass with respect to 100 parts by mass of the binder.
[0055]
The release agent is preferably contained in the release layer 22 in an amount of 0 to 100 parts by mass, preferably 2 to 50 parts by mass, more preferably 5 to 20 parts by mass with respect to 100 parts by mass of the binder.
[0056]
After the release layer 22 is formed on the surface of the carrier sheet 30, as shown in FIG. 2A, an electrode layer 12 a that will constitute the internal electrode layer 12 after firing is formed on the surface of the release layer 22 in a predetermined pattern. Form.
[0057]
The thickness of the formed electrode layer (alloy thin film) 12a is preferably about 0.1 to 1 μm, and more preferably about 0.1 to 0.5 μm. The electrode layer 12a may be composed of a single layer, or may be composed of two or more layers having different compositions.
[0058]
The electrode layer 12a is formed on the surface of the release layer 22 by a thin film method such as vapor deposition or sputtering.
[0059]
When the electrode layer 12a is formed on the surface of the peeling layer 22 by a sputtering method, which is a kind of a thin film method, it is performed as follows.
[0060]
In the present invention, an alloy having a specific composition is used as a sputtering target material. The alloy used in the present invention contains nickel (Ni) and tungsten (W). The content of Ni in the alloy is 80 to 100 mol% (excluding 100 mol%), and preferably 83 to 94 mol%. The content of W in the alloy is 0 to 20 mol% (excluding 0 mol%), preferably 6 to 17 mol%. When the amount of W exceeds 20 mol%, problems such as an increase in resistivity occur. The alloy may contain various trace components such as P at about 0.1 mol% or less.
[0061]
The alloy used in the present invention can be produced by, for example, a plating method, a vapor deposition method, a sputtering method, or the like.
[0062]
In this embodiment, sputtering is performed using the above alloy as a target material.
[0063]
As the sputtering conditions, the ultimate vacuum degree is preferably 10^-2Pa or less, more preferably 10^-3Pa or less, Ar gas introduction pressure is preferably 0.1 to 2 Pa, more preferably 0.3 to 0.8 Pa, output is preferably 50 to 400 W, more preferably 100 to 300 W, and sputtering temperature is preferably 20 to 150 W. ° C, more preferably 20 to 120 ° C.
[0064]
In the present invention, since an alloy having a specific composition is used as the sputter target, the composition of the obtained metal thin film is a Ni alloy thin film having the same ratio as the target.
[0065]
The electrode layer 12a formed on the surface of the release layer 22 has a peak of the crystal plane (111) of 2θ = 45 ° in the X-ray diffraction chart when Cu-kα rays are used as the X-ray source shown in FIG. The peak of the crystal plane (200) was observed near 2θ = 52 °, and the peak of the crystal plane (220) was observed near 2θ = 77 °. When I (111), the peak intensity of the diffraction line on the crystal plane (200) plane is I (200), and the peak intensity of the diffraction line on the crystal plane (220) plane is I (220), (I (111) ) / I (200)) ≧ 3 and (I (111) / I (220)) ≧ 3, preferably containing an alloy having a main surface, more preferably (I (111) / I ( 200)) ≧ 5 and (I (111) / I (220) ) Comprises an alloy that has a main surface that satisfies the relationship of ≧ 5. In the present invention, it is preferable to use a metal having such crystal orientation as the electrode layer 12a.
[0066]
When (I (111) / I (200)) and (I (111) / I (220)) are small, inconveniences such as spheroidization and interruption may occur. The upper limits of (I (111) / I (200)) and (I (111) / I (220)) are 1:10 and 1:20, respectively.
[0067]
The electrode layer 12a formed on the surface of the release layer 22 contains an alloy having a crystallite size of preferably 10 to 100 nm, more preferably 20 to 40 nm. If the crystallite size is too small, problems such as spheroidization and interruption occur, and if the crystallite size is too large, problems such as variation in film thickness occur.
[0068]
(3) Separately from the carrier sheets 20 and 30, as shown in FIG. 2A, an adhesive layer transfer sheet having an adhesive layer 28 formed on the surface of a carrier sheet 26 as a third support sheet is used. prepare. The carrier sheet 26 is configured by a sheet similar to the carrier sheets 20 and 30.
[0069]
The composition of the adhesive layer 28 is the same as that of the release layer 22 except that it does not contain dielectric particles. That is, the adhesive layer 28 includes a binder, a plasticizer, and a release agent. The adhesive layer 28 may include the same dielectric particles as the dielectric constituting the green sheet 10a. However, when the adhesive layer having a thickness smaller than the particle diameter of the dielectric particles is formed, the dielectric particles may be used. Should not be included. When dielectric particles are included in the adhesive layer 28, the ratio of the dielectric particles to the binder weight is preferably smaller than the ratio of the dielectric particles included in the green sheet to the binder weight.
[0070]
The binder and plasticizer for the adhesive layer 28 are preferably the same as the release layer 22, but may be different.
[0071]
It is preferable that the plasticizer is contained in the adhesive layer 28 in an amount of 0 to 200 parts by mass, preferably 20 to 200 parts by mass, more preferably 50 to 100 parts by mass with respect to 100 parts by mass of the binder.
[0072]
The thickness of the adhesive layer 28 is preferably about 0.02 to 0.3 μm. If the thickness of the adhesive layer 28 is too thin, the adhesive strength is reduced, and if it is too thick, defects (gaps) tend to occur.
[0073]
The adhesive layer 28 is formed on the surface of the carrier sheet 26 as the third support sheet by, for example, a bar coater method, a die coater method, a reverse coater method, a dip coater method, a kiss coater method, and dried as necessary. The drying temperature is not particularly limited, but is preferably room temperature to 80 ° C., and the drying time is preferably 1 to 5 minutes.
[0074]
(4) In order to form an adhesive layer on the surface of the electrode layer 12a shown in FIG. That is, as shown in FIG. 2B, the adhesive layer 28 of the carrier sheet 26 is pressed against the surface of the electrode layer 12a, heated and pressurized, and then the carrier sheet 26 is peeled off, as shown in FIG. 2C. Thus, the adhesive layer 28 is transferred to the surface of the electrode layer 12a.
[0075]
The heating temperature at that time is preferably 40 to 100 ° C., and the pressure is preferably 0.2 to 15 MPa. Pressing may be performed by a press or a calender roll, but is preferably performed by a pair of rolls.
[0076]
After that, the electrode layer 12a is bonded to the surface of the green sheet 10a formed on the surface of the carrier sheet 30 shown in FIG. For this purpose, as shown in FIG. 3B, the electrode layer 12a of the carrier sheet 20 is pressed together with the carrier sheet 20 onto the surface of the green sheet 10a via the adhesive layer 28, and is heated and pressurized. 2), the electrode layer 12a is transferred to the surface of the green sheet 10a. However, since the carrier sheet 30 on the green sheet side is peeled off, the green sheet 10a is transferred to the electrode layer 12a via the adhesive layer 28 when viewed from the green sheet 10a side.
[0077]
The heating and pressurizing at the time of transfer may be pressurizing and heating by a press or pressurizing and heating by a calendar roll, but are preferably performed by a pair of rolls. The heating temperature and the pressing force are the same as when the adhesive layer 28 is transferred.
[0078]
2 (A) to 3 (C), a single layer of the electrode layer 12a having a predetermined pattern is formed on the single green sheet 10a. In order to stack the green sheets 10a on which the electrode layers 12a are formed, for example, the steps shown in FIGS. 4A to 6C may be repeated. 4 (A) to 6 (C), members common to those shown in FIGS. 3 (A) to 4 (C) are denoted by the same reference numerals, and the description thereof is partially omitted. .
[0079]
First, as shown in FIGS. 4A to 4C, the adhesive layer 28 is transferred to the surface (back surface) of the green sheet 10a on the side opposite to the electrode layer. Thereafter, as shown in FIGS. 5A to 5C, the electrode layer 12a is transferred to the back surface of the green sheet 10a via the adhesive layer 28.
[0080]
Next, as shown in FIGS. 6A to 6C, the green sheet 10a is transferred to the surface of the electrode layer 12a via the adhesive layer 28. Thereafter, by repeating these transfers, a laminate in which a large number of the electrode layers 12a and the green sheets 10a are alternately laminated is obtained.
[0081]
(5) Then, after the laminate is finally pressed, the carrier sheet 20 is peeled off. The pressure at the time of final pressurization is preferably 10 to 200 MPa. The heating temperature is preferably from 40 to 100C.
[0082]
Thereafter, the laminate is cut into a predetermined size to form a green chip. Then, the green chip is subjected to binder removal processing and firing.
[0083]
In the case of using a Ni alloy as a base metal as the conductor material of the internal electrode layer as in the present invention, the oxygen partial pressure in the binder removal atmosphere is reduced to 10%.⁻⁴⁵-10⁵It is preferably Pa. As other binder removal conditions, the temperature raising rate is preferably 5 to 300 ° C / hour, more preferably 10 to 50 ° C / hour, and the holding temperature is preferably 200 to 400 ° C, more preferably 250 to 350 ° C. The temperature and the temperature holding time are preferably 0.5 to 20 hours, more preferably 1 to 10 hours. The debinding atmosphere is preferably air or a reducing atmosphere. As the atmosphere gas in the reducing atmosphere, for example, N 2 is used.₂And H₂It is preferable to use a mixed gas of humidified and used.
[0084]
In the present invention, the firing of the green chips is carried out at an oxygen partial pressure of preferably 10%.^-14-10^-8Pa, more preferably 10^-11-10^-9Performed in an atmosphere of Pa. If the oxygen partial pressure during firing is too low, the conductive material of the internal electrode layer may cause abnormal sintering and may be interrupted, while if the oxygen partial pressure is too high, the internal electrode layer tends to oxidize. . In particular, W used as a part of the internal electrode material in the present invention is useful for preventing spheroidization after sintering, but has the property of being easily oxidized as compared with Ni. Therefore, under normal Ni firing conditions, that is, under a relatively high oxygen partial pressure, W is oxidized, and a decrease in capacitance is inevitable. In the present invention, in order to prevent W from being oxidized, the green chip is fired in an atmosphere having a low oxygen partial pressure. That is, if the green chip is fired at the oxygen partial pressure in the above range, W is not oxidized. As a result, it is possible to contribute to suppressing a decrease in capacitance without causing spheroidization of the internal electrode.
[0085]
In the present invention, firing of the green chip is performed at a low temperature of 1300 ° C. or less, more preferably 1000 to 1300 ° C., and particularly preferably 1150 to 1250 ° C. If the firing temperature is too low, the green chip will not be dense. Conversely, if the firing temperature is too high, the internal electrodes will be interrupted, the capacitance-temperature characteristics will deteriorate due to the diffusion of the conductive material, and the reduction of the dielectric will occur. Because.
[0086]
Other firing conditions include a heating rate of preferably 50 to 500 ° C / hour, more preferably 200 to 300 ° C / hour, and a temperature holding time of preferably 0.5 to 8 hours, more preferably 1 to 3 hours. The time and the cooling rate are preferably 50 to 500 ° C / hour, more preferably 200 to 300 ° C / hour. The firing atmosphere is preferably a reducing atmosphere.₂And H₂Is preferably used in a dry (dry) state.
[0087]
In the present invention, it is preferable to anneal the fired capacitor chip body. Annealing is a process for reoxidizing the dielectric layer, whereby the accelerated life of the insulation resistance (IR) can be significantly increased, and the reliability is improved.
[0088]
In the present invention, it is preferable that the annealing of the capacitor chip body after firing is performed under a higher oxygen partial pressure than the reducing atmosphere at the time of firing.^-2-10 Pa, more preferably 10^-1It is performed in an atmosphere of 〜１０10 Pa. If the oxygen partial pressure during annealing is too low, reoxidation of the dielectric layer 2 is difficult, and if it is too high, the internal electrode layer 3 tends to be oxidized.
[0089]
In the present invention, the holding temperature or the maximum temperature during annealing is preferably 900 ° C. or lower, more preferably 600 to 900 ° C., and particularly preferably 750 to 850 ° C. In the present invention, the holding time at these temperatures is preferably 4 to 20 hours, more preferably 8 to 20 hours, and further preferably 10 to 14 hours. If the holding temperature or the maximum temperature during annealing is less than the above-mentioned range, the dielectric resistance material tends to be insufficiently oxidized, thereby shortening the insulation resistance life. Not only does it decrease, but it also reacts with the dielectric substrate, which tends to shorten its life. Note that the annealing may include only the temperature increasing process and the temperature decreasing process. That is, the temperature holding time may be set to zero. In this case, the holding temperature is synonymous with the maximum temperature.
[0090]
That is, the present invention is characterized in that annealing is performed at a relatively low holding temperature or the maximum temperature for a long time. As described above, W used as a part of the internal electrode material in the present invention is more easily oxidized than Ni. Therefore, if annealing is performed under normal Ni annealing conditions, that is, at a relatively high temperature for a short time, W is oxidized, and a decrease in capacitance is inevitable. In the present invention, in order to prevent oxidation of W, annealing is performed at a relatively low holding temperature or the maximum temperature for a long time. That is, W is not oxidized by annealing for a long time at the holding temperature or the maximum temperature in the above range. As a result, it is possible to contribute to suppressing a decrease in capacitance without causing spheroidization of the internal electrode.
[0091]
As other annealing conditions, the cooling rate is preferably 50 to 500 ° C./hour, more preferably 100 to 300 ° C./hour. As the atmosphere gas for annealing, for example, humidified N₂It is preferable to use gas or the like.
[0092]
Note that N₂In order to humidify the gas, for example, a wetter may be used. In this case, the water temperature is preferably about 0 to 75 ° C.
[0093]
The binder removal treatment, firing and annealing may be performed continuously or independently. When these are continuously performed, after removing the binder, the atmosphere is changed without cooling, and then the temperature is raised to the holding temperature at the time of firing, firing is performed, and then cooling is performed, and the temperature reaches the holding temperature of annealing. It is preferable to change the atmosphere sometimes and perform annealing. On the other hand, when these are performed independently, during firing, N₂Gas or humidified N₂After raising the temperature in a gas atmosphere, it is preferable to change the atmosphere and continue to raise the temperature further.₂Gas or humidified N₂It is preferable to change to a gas atmosphere and continue cooling. When annealing, N₂After raising the temperature to the holding temperature in a gas atmosphere, the atmosphere may be changed, and the entire annealing process is performed by humidified N₂A gas atmosphere may be used.
[0094]
The thus obtained sintered body (element body 4) is subjected to end face polishing by, for example, barrel polishing, sand plasting or the like, and the terminal electrode paste is baked to form the terminal electrodes 6, 8. The firing conditions for the terminal electrode paste are, for example, humidified N₂And H₂It is preferable to set the temperature at 600 to 800 ° C. for about 10 minutes to 1 hour in a mixed gas of the above. Then, a pad layer is formed by plating or the like on the terminal electrodes 6 and 8 as necessary. Note that the terminal electrode paste may be prepared in the same manner as the above-mentioned electrode paste.
[0095]
The multilayer ceramic capacitor of the present invention thus manufactured is mounted on a printed circuit board or the like by soldering or the like, and is used for various electronic devices and the like.
[0096]
In the manufacturing method of the multilayer ceramic capacitor according to the present embodiment, the internal electrode layer before firing including the Ni-W alloy having the specific composition is fired in an atmosphere having a lower oxygen partial pressure than normal Ni firing conditions. Thereby, while increasing the sintering start temperature of the Ni—W alloy that constitutes the internal electrode layer, spheroidization due to grain growth is suppressed, and the internal electrode is continuously formed. Can be suppressed. In the present embodiment, after the baking, annealing is performed at a temperature lower than normal Ni annealing conditions for a longer time. By this annealing treatment, re-oxidation of the dielectric layer is achieved, semiconductor formation is prevented, and high insulation resistance can be obtained.
[0097]
In this embodiment, the dry type electrode layer 12a can be easily and accurately transferred onto the surface of the green sheet 10a without breaking or deforming the green sheet 10a. In particular, an adhesive layer 28 is formed on the surface of the electrode layer or the green sheet by a transfer method, and the electrode layer 12a is adhered to the surface of the green sheet 10a via the adhesive layer 28. The formation of the adhesive layer 28 eliminates the need for high pressure and heat when bonding and transferring the electrode layer 12a to the surface of the green sheet 10a, and enables bonding at lower pressure and lower temperature. Therefore, even when the green sheet 10a is extremely thin, the green sheet 10a is not broken, and the electrode layer 12a and the green sheet 10a can be satisfactorily laminated, and a short circuit does not occur.
[0098]
Further, for example, by making the adhesive strength of the adhesive layer 28 stronger than the adhesive strength of the release layer 22 and making the adhesive strength of the release layer 22 stronger than the adhesive strength between the green sheet 10a and the carrier sheet 30. The carrier sheet 30 on the green sheet 10a side can be selectively and easily peeled off.
[0099]
Furthermore, since the adhesive layer 28 is not formed directly on the surface of the electrode layer 12a or the green sheet 10a by a coating method but formed by a transfer method, the components of the adhesive layer 28 permeate the electrode layer 12a or the green sheet 10a. And an extremely thin adhesive layer 28 can be formed. For example, the thickness of the adhesive layer 28 can be reduced to about 0.02 to 0.3 μm. Even if the thickness of the adhesive layer 28 is small, the components of the adhesive layer 28 do not penetrate into the electrode layer 12a or the green sheet 10a, so that the adhesive strength is sufficient and the composition of the electrode layer 12a or the green sheet 10a is adversely affected. There is no fear of giving.
[0100]
As described above, the embodiments of the present invention have been described. However, the present invention is not limited to these embodiments at all, and it goes without saying that the present invention can be implemented in various modes without departing from the gist of the present invention. .
[0101]
For example, the method of the present invention is not limited to a method for manufacturing a multilayer ceramic capacitor, but can be applied to a method for manufacturing other electronic components having internal electrodes.
[0102]
【Example】
Hereinafter, the present invention will be described based on more detailed examples, but the present invention is not limited to these examples.
[0103]
Preparation of each paste
First, BaTiO₃Powder (BT-02 / Sakai Chemical Industry Co., Ltd.) and MgCO₃, MnCO₃, (Ba_0.6Ca_0.4) SiO₃And rare earth (Gd₂O₃, Tb₄O₇, Dy₂O₃, Ho₂O₃, Er₂O₃, Tm₂O₃, Yb₂O₃, Lu₂O₃, Y₂O₃) Was wet-mixed with a ball mill for 16 hours and dried to obtain a dielectric material. The average particle size of these raw material powders was 0.1 to 1 μm. (Ba_0.6Ca_0.4) SiO₃Is BaCO₃, CaCO₃And SiO₂Was wet-mixed with a ball mill for 16 hours, dried, and then fired in air at 1150 ° C., and wet-pulverized with a ball mill for 100 hours.
In order to paste the obtained dielectric material, an organic vehicle was added to the dielectric material and mixed with a ball mill to obtain a dielectric green sheet paste. The organic vehicle is based on 100 parts by mass of the dielectric material, polyvinyl butyral: 6 parts by mass as a binder, bis (2-ethylhexyl) phthalate (DOP): 3 parts by mass, ethyl acetate: 55 parts by mass, toluene: The mixing ratio was 10 parts by mass and 0.5 parts by mass of paraffin as a release agent.
[0104]
Next, the dielectric green sheet paste was diluted twice with ethanol / toluene (55/10) at a weight ratio to obtain a release layer paste.
[0105]
Next, the same paste for a dielectric green sheet as described above except that the dielectric particles and the release agent were not added was diluted by a factor of 4 with toluene to obtain a paste for an adhesive layer.
[0106]
Green sheet formation
First, a green sheet having a thickness of 1.0 μm was formed on a PET film (second support sheet) using the above-mentioned paste for a dielectric green sheet using a wire bar coater.
[0107]
Formation of electrode layer
The release layer paste was applied and dried on another PET film (first support sheet) using a wire bar coater to form a 0.2 μm thick release layer.
[0108]
Next, a mask on which a predetermined pattern to be an internal electrode was formed was set on the surface of the release layer, and an electrode layer (Ni alloy thin film) having a predetermined thickness (see each table) was formed by a sputtering method. As the sputtering conditions, the ultimate vacuum degree: 10^-3Pa or less, Ar gas introduction pressure: 0.5 Pa, output: 200 W, temperature: room temperature (20 ° C.). Also, a sputtering target obtained by mixing Ni and W into a predetermined composition as shown in each table and cutting out into a shape having a diameter of about 4 inches and a thickness of 3 mm was used.
[0109]
Evaluation of electrode layer (sputtering thin film)
X-ray diffraction confirmed that W was dissolved in Ni. The crystallite size (unit: nm) was determined from the half width. FIG. 7 shows X-ray diffraction charts of sputtered thin films of an example sample (Ni = 97 mol%) of Table 1 described later and a reference example sample (Ni = 100 mol%) of Table 1 similarly. In the X-ray diffraction chart shown in FIG. 7, it is confirmed that the peak of the crystal plane (111) of the Ni alloy particles occurs near 2θ = 45 °, and the peak of the crystal plane (200) occurs near 2θ = 52 °. . Although the peak of the crystal plane (220) occurs near 2θ = 77 °, it is not shown in FIG. The heights of these X-ray diffraction peaks are taken as X-ray diffraction intensities, and the crystal plane (200) and the intensity ratio of the crystal plane (111) to the crystal plane (200) are derived by the above-described relationship, so that the metal The crystal orientation of the thin film was evaluated.
Specifically, the I (111) / I (200) value and the I (111) / I (220) value of the sputtering thin film in the X-ray diffraction chart shown in FIG. 7 are shown in each table. The X-ray diffraction chart of the sputtered thin film was measured with a powder X-ray (Cu-Kα ray) diffractometer under the following conditions. The X-ray generation conditions were as follows: output: 45 kV-40 mA, scan width: 0.2 ° / min. The X-ray detection conditions were as follows: parallel slit: 1.0 °, divergent slit: 1.0 °, attended slit: 0.30 mm.
[0110]
The thickness (thickness) of the sputtering thin film was determined by observing with a SEM.
[0111]
Formation of adhesive layer
The above adhesive layer paste is applied to a separate PET film (third support sheet), the surface of which has been subjected to a release treatment with a silicone resin, by a wire bar coater and dried to form an adhesive layer having a thickness of 0.2 μm. 28 were formed.
[0112]
Formation of final laminate (element body before firing)
First, the adhesive layer 28 was transferred to the surface of the electrode layer 12a by the method shown in FIG. At the time of transfer, a pair of rolls was used, the pressure was 0.1 MPa, and the temperature was 80 ° C.
[0113]
Next, the internal electrode layer 12a was bonded (transferred) to the surface of the green sheet 10a via the bonding layer 28 by the method shown in FIG. At the time of transfer, a pair of rolls was used, the pressure was 0.1 MPa, and the temperature was 80 ° C.
[0114]
Next, the internal electrode layers 12a and the green sheets 10a were successively laminated by the method shown in FIGS. 4 to 6 to finally obtain a final laminate in which 21 internal electrode layers 12a were laminated. The laminating conditions were a pressure of 5 MPa and a temperature of 120 ° C.
[0115]
Production of sintered body
Next, the final laminate was cut into a predetermined size, subjected to binder removal treatment, baked, and annealed (heat treated) to produce a chip-shaped sintered body.
[0116]
The binder removal is
Heating rate: 15-50 ° C / hour,
Holding temperature: 400 ° C,
Retention time: 2 hours,
Cooling rate: 300 ° C / hour,
Atmosphere gas: dry N₂And H₂Gas mixture,
Oxygen partial pressure: 10^-3Pa,
I went in.
[0117]
Firing
Heating rate: 200-300 ° C / hour,
Retention temperature: Refer to each table,
Retention time: 2 hours,
Cooling rate: 300 ° C / hour,
Atmosphere gas: dry N₂And H₂Gas mixture,
Oxygen partial pressure: Refer to each table,
I went in.
[0118]
Annealing (re-oxidation)
Heating rate: 200-300 ° C / hour,
Retention temperature: Refer to each table,
Retention time: Refer to each table,
Cooling rate: 200 ° C / hour,
Atmosphere gas: Humidified N₂gas,
Oxygen partial pressure: Refer to each table,
I went in. The humidification of the atmosphere gas was performed at a water temperature of 0 to 75 ° C. using a wetter.
[0119]
Next, after polishing the end face of the chip-shaped sintered body by sand blasting, the external electrode paste was transferred to the end face, and humidified N₂+ H₂In an atmosphere, firing was performed at 800 ° C. for 10 minutes to form external electrodes, and a sample of the multilayer ceramic capacitor having the configuration shown in FIG. 1 was obtained.
[0120]
The size of each sample thus obtained was 3.2 mm × 1.6 mm × 0.6 mm, the number of dielectric layers sandwiched between the internal electrode layers was 21, the thickness was 1 μm, The thickness of the internal electrode layer was 0.5 μm. Each sample was evaluated for electrical characteristics (capacitance C, resistivity, dielectric loss tan δ). The results are shown in each table. The electrical characteristics (capacitance C, resistivity, dielectric loss tan δ) were evaluated as follows.
[0121]
The capacitance C (unit: μF) was measured for the sample at a reference temperature of 25 ° C. using a digital LCR meter (4274A manufactured by YHP) under the conditions of a frequency of 1 kHz and an input signal level (measurement voltage) of 1 Vrms. The capacitance C is preferably 0.7 μF or more.
[0122]
The resistivity (unit: Ω · m) was determined by measuring the sputtered film (before firing) formed on a glass substrate using a resistivity meter (NPS, Σ-5) at 25 ° C. using a DC four-point probe method. (Current 1 mA, 2 seconds). The resistivity is preferably 70 × 10^-8Ω · m or less was regarded as good.
[0123]
The dielectric loss tan δ (unit:%) was measured at 125 ° C. with a digital LCR meter (4274A manufactured by YHP) under the conditions of a frequency of 1 kHz and an input signal level (measurement voltage) of 1 Vrms. The dielectric loss tan δ is preferably less than 0.1%.
[0124]
In addition, these characteristic values were obtained from the average value of the values measured using n = 10 samples.
[0125]
[Table 1]

[0126]
[Table 2]

[0127]
[Table 3]

[0128]
[Table 4]

[0129]
[Table 5]

[0130]
[Table 6]

[0131]
[Table 7]

[0132]
As shown in Table 1, with respect to the contents of Ni and W (unit: mol%), when Ni: W = 100: 0, the decrease in capacitance could not be suppressed. When Ni: W = 75: 25, the decrease in capacitance could be suppressed, but the resistivity increased and tan δ increased. On the other hand, when Ni: W = 80 to 100 (except 100): 0 to 20 (except 0), it is possible to suppress a decrease in capacitance without causing an increase in resistivity and tan δ. Was confirmed.
[0133]
As shown in Table 2, with respect to the thickness of the alloy thin film, when the thickness of the alloy film was 0.05 μm, the electrode layer was spheroidized, and the decrease in capacitance could not be suppressed. On the other hand, it was confirmed that when the thickness of the alloy film was 0.1 to 1 μm, the decrease in capacitance could be suppressed without causing the electrode layer to be spherical.
[0134]
As shown in Table 3, with respect to the firing temperature during firing, when the firing temperature was 950 ° C., the dielectric layer was insufficiently sintered, and the decrease in capacitance could not be suppressed. When the firing temperature was 1350 ° C., the electrode layer was spheroidized and oxidized and diffused into the dielectric layer, so that the decrease in capacitance could not be suppressed. On the other hand, if the firing temperature is 1000 to 1300 ° C., it is confirmed that the decrease in capacitance can be suppressed without causing insufficient sintering, spheroidization of the electrode layer, and diffusion of the electrode layer into the dielectric layer. Was done.
[0135]
As shown in Table 4, with respect to the oxygen partial pressure during firing, the oxygen partial pressure = 10^-15When the pressure was Pa, the electrode layer became spherical and interrupted, and the decrease in capacitance could not be suppressed. Oxygen partial pressure = 10^-7When the pressure is Pa, the electrode layer is spheroidized and oxidized, and diffuses into the dielectric layer, so that a decrease in capacitance cannot be suppressed. On the other hand, oxygen partial pressure = 10^-14-10^-8It was confirmed that when the pressure was Pa, it was possible to suppress a decrease in capacitance without causing spheroidization and interruption of the electrode layer and diffusion of the electrode layer into the dielectric layer.
[0136]
As shown in Tables 5 to 7, regarding the holding temperature, oxygen partial pressure and temperature holding time during annealing, holding temperature = 550 ° C., oxygen partial pressure = 10^-3When Pa and the temperature holding time were 3 to 4 hours, tan δ tended to increase, but all were within the allowable range. Holding temperature = 950 ° C., oxygen partial pressure = 10²When Pa and the temperature holding time are 21 hours, the capacitance tends to decrease, but both are within the allowable range. On the other hand, holding temperature = 600-900 ° C., oxygen partial pressure = 10^-2-10¹It was confirmed that when Pa and the temperature holding time were 8 to 20 hours, it was possible to suppress a decrease in capacitance while suppressing tan δ to be low.
[0137]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a method for manufacturing an electronic component having an internal electrode such as a multilayer ceramic capacitor capable of effectively suppressing a decrease in capacitance.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a multilayer ceramic capacitor according to one embodiment of the present invention.
FIGS. 2A to 2C are cross-sectional views of a main part showing a method of transferring an electrode layer.
3 (A) to 3 (C) are cross-sectional views of relevant parts showing a step that follows the step shown in FIG. 2;
FIGS. 4A to 4C are cross-sectional views of a main part showing a method of laminating a green sheet to which an electrode layer is adhered.
5 (A) to 5 (C) are cross-sectional views of relevant parts showing a method of laminating a green sheet to which an electrode layer is adhered, showing a step subsequent to FIG.
6 (A) to 6 (C) are cross-sectional views of relevant parts showing a step following that shown in FIG. 5. FIG.
FIG. 7 is an X-ray diffraction chart of the alloy powder according to one embodiment of the present invention.
[Explanation of symbols]
2. Multilayer ceramic capacitor
4 ... capacitor body
6, 8 ... terminal electrode
10 ... Dielectric layer
10a ... Green sheet
12 Internal electrode layer
12a ... electrode layer
20 Carrier sheet (first support sheet)
22 ... release layer
26 ... Carrier sheet (third support sheet)
28 ... adhesive layer
30 ... Carrier sheet (second support sheet)

Claims (6)

A method for producing an electronic component having internal electrodes, comprising a step of firing a green chip formed by laminating a green sheet to which an electrode layer formed in a predetermined pattern by a thin film method is adhered together with another green sheet. ,
It contains nickel (Ni) and tungsten (W), and the content of each component is as follows: Ni: 80 to 100 mol% (excluding 100 mol%), W: 0 to 20 mol% (however, 0 mol) % Except), using an electrode layer having a thickness of 0.1 to 1 μm,
A method for producing an electronic component having internal electrodes, characterized by firing in an atmosphere having an oxygen partial pressure of 10 ^-14 to 10 ^-8 Pa at a temperature of 1000 to 1300C. 2. The internal part according to claim 1, further comprising a step of annealing at a temperature of 600 to 900 ° C. for 4 to 20 hours in an atmosphere having an oxygen partial pressure of 10 ⁻² to 10 Pa after the step of firing the green chip. A method for manufacturing electronic components having electrodes. In the X-ray diffraction chart, the peak intensity of the diffraction line on the crystal plane (111) is I (111), the peak intensity of the diffraction line on the crystal plane (200) is I (200), and the crystal plane (220) plane is obtained. Alloy having a main surface satisfying the relations of I (111) / I (200)) ≧ 3 and I (111) / I (220)) ≧ 3, where I (220) is the peak intensity of the diffraction line of The method for producing an electronic component having an internal electrode according to claim 1, wherein the method comprises using an electrode layer containing: 4. The method for manufacturing an electronic component having internal electrodes according to claim 1, wherein an electrode layer containing an alloy having a crystallite size of 10 to 100 nm is used. 5. The method for manufacturing an electronic component having internal electrodes according to claim 1, wherein an electrode layer formed in a predetermined pattern by a sputtering method is used. An electronic component having an internal electrode, manufactured by the method according to any one of claims 1 to 5.

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