JPS631726B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing ceramic electronic components that is easy to manufacture, inexpensive, and has stable characteristics. Conventionally, when manufacturing electrode materials for ceramic electronic components that utilize the functional properties of dielectrics, piezoelectrics, semiconductors, etc., Ag, Ag-Pd, Ag-
Baked electrode methods mainly using noble metals such as Pt, Ag-Ni, etc. have been put into practical use. However, with the recent rise in the price of precious metals, various plating methods are being developed.
However, these methods also have many drawbacks.
For example, it is possible to form baked silver electrodes on the surface of the porcelain body and then provide nickel electrodes or copper electrodes by electrolytic plating, but with this method, the surface of the baked metal layer is rough and has many small holes. Therefore, during the plating process, the plating liquid penetrates into the small holes, which deteriorates the adhesion strength between the fired metal layer and the porcelain body. Another method used is the electroless plating method, which generally involves first subjecting tin chloride and palladium chloride to a catalytic activation treatment through a chemical reaction.
However, there are many problems when used as electrodes for ceramic electronic components. In other words, depending on the type of electrode material and related materials and the mounting method, the tensile strength (reduced to 1/2 compared to silver-baked electrodes) and electrical properties (deterioration of properties due to life tests) were significantly degraded. . For example, when forming electrodes on ceramic capacitors, piezoelectric elements, and semiconductor elements, the electroless nickel plating method tends to form electrodes on the entire circumferential surface of the substrate due to the nature of the method. An electrode is formed, but in this case, the creepage withstand voltage distance is determined by the thickness of the substrate, and the concentration of the electric field at the edge of the electrode tends to cause dielectric breakdown, so the thickness of the substrate cannot be made very thin. It was hot. In contrast to these methods, the partial plating method involves applying a resin plating resist to the required portions of the porcelain surface in advance when forming a metal layer with a desired pattern on the porcelain surface, then activating the porcelain surface and applying the plating resist. There are various methods such as removing the metal layer and then applying electroless plating to form a metal layer on the porcelain surface, vacuum evaporation method, photo etching method, etc., but all of them give satisfactory results as electrodes for ceramic electronic components. I can't get it. In other words, the adhesion of the plating is poor with conventional plating methods, and the thickness of capacitor products aimed at miniaturization is as thin as 0.1 to 0.3 m/m, and the shapes vary from 4.5 to 16 φ. This was difficult when considering mass production. Furthermore, if electrodes are formed on the entire surface in order to obtain as large a capacitance value as possible, the life characteristics will be extremely poor as described above, and from the viewpoint of reliability, it is necessary in the design to provide an edge on the electrode portion of the porcelain surface. It was hot. The present invention is directed to a method for manufacturing ceramic electronic components that eliminates many of the above-mentioned drawbacks and has extremely stable lifetime characteristics. That is, in the present invention, Ag components of 99.5 to 55 wt%, Co,
A mixed paint consisting of an electrode material containing one or more of Fe, Sn, Mo, W, Mn, Zn, and Cu components in a ratio range of 0.5 to 45 wt% and an organic binder is applied, and then 350 Heat treatment is performed at a temperature range of ℃~880℃ to form a 0.1~1.5μ metal fine particle layer on the substrate, and then Pd, Pt, Ph, Os, Ir, Ru
The method of the present invention is characterized by performing a substitution treatment in a solution containing at least one kind of metal ions, and then forming a nickel or copper metal electrode by an electroless plating method. The electrode thus obtained has much better properties than those obtained by the conventional baked silver electrode method and can provide sufficient functionality. Examples of the present invention will be described below. PbTiO ₃ −BaTiO ₃ − is used as a dielectric ceramic substrate.
Using SrTiO ₃ −Bi ₂ O ₃ based body, thickness 0.15~
After performing surface treatment with hydrofluoric acid and nitric acid to roughen the surface of a 1.3m/m, 4φ to 12φ substrate,
A spraying or printing method was used using a mask that left edges of 1 m/m on both sides of the substrate (device).
In addition, to create a paint containing one or more types of Ag compounds, Ag powder and various metal powders are used, and the proportion of the metal components is 5 to 5.
30wt%, 5 to 10wt% of organic binder components such as amide, phenol, and cellulose, and solvent components such as ethyl celloselb, butyl carbitol, and alcohol as the remainder, and the viscosity for printing (approximately 30,000 to 60,000 cps). For spraying (100~
400 cps) and applied to both sides of the ceramic substrate. After drying at a temperature of 80℃ to 100℃ to evaporate the solvent, baking is performed in an electric furnace at a temperature range of 450℃ to 880℃ to form a layer of metal or alloy fine particles of 0.1 to 1.5μ. , Pt, Ph, Os, Ir, Ru
A substitution treatment was performed in a solution containing 0.001 wt% of metal ions such as, and then immersed in a plating solution containing nickel sulfate and sodium hypophosphite to form a nickel film. For copper plating, a copper film was formed using copper sulfate. Next, as a method with lead terminals,
Lead wires were attached using a dipping method using a Pb-Sn based solder material, and then impregnated with a phenol based coating resin and wax to create a finished product. In addition, in the present invention, it is necessary to apply a paste containing an Ag component and one or more of Mo, W, Mn, Zn, and Cu components, and then perform baking at a temperature between 350°C and 880°C. The purpose is to form a stable metal fine particle layer on the ceramic substrate surface. If the temperature is below 350°C, the resin component will remain, making the formation of the metal electrode unstable and reducing the tensile strength after plating. Moreover, the loss angle also worsens.
At temperatures above 880°C, some of the metal components will melt, making plating difficult. Further, the electrical characteristics are also deteriorated, which is not preferable. Silver content: 99.5% or more, Co, Fe, Sn, Mo,
If the W, Mn, Zn, or Cu content is less than 0.5%, the adhesive strength with the substrate decreases, which is not preferable. Also, Ag content 55wt%
Below, Co, Fe, Sn, Mo, W, Mn, Zn, and Cu components of 45 wt % or more are not preferable because an oxide film is formed, the electrical properties deteriorate, and the adhesive strength with the substrate decreases. In addition, in the present invention, 0.1 to 1.5μ after paint baking
The function as an electrode is created by depositing metals such as Pt, Pd, Ph, Os, Ir, and Ru on the metal particle layer, and then plating with Ni and Cu. Baked silver, which is conventionally used as an electrode material for capacitors, has a film thickness of 3 to 20 μm after baking.
The film layer itself can be used as an electrode layer, but the metal particle layer of the present invention after baking is extremely thin, less than 1.5μ, and does not function as an electrode by itself. Also, it cannot be soldered, so Pd, Pt, Ph, Os,
Only by plating Ni and Cu after the metal deposition of Ir and Ru, can it be used as an electrode function and can also be soldered. In addition, the present invention can fully exhibit its function as long as the metal particle layer exists within the range of 0.1 to 1.5μ after baking, and when used as an electrode for a capacitor, if the metal particle layer is 1.5μ or more, Compared to conventional baked silver (silver thickness 5 to 20 μm), it does not have any advantages in terms of price, and is undesirable because Ag ion migration occurs particularly in the humidity load life characteristics. Although only dielectric ceramic materials have been described in this example, there is no problem with other ceramic materials that can withstand temperatures of 350°C or higher, such as piezoelectric materials, insulators, and ceramic semiconductors, and conventional immersion electroless plating methods can be used. This is a method for manufacturing ceramic electronic components using a new plating method that is completely different from the previous method. In the present invention, a small amount of glass powder, Bi ₂ O ₃ , Pb ₃ O ₄ ,
B ₂ O ₃ etc. are also effective. Also, trace amounts of Co and Cr in Ni plating etc. also have the effect of increasing hardness. Furthermore, it is also effective to add small amounts of carbon powder, clay, etc. to prevent "sagging" during screening. In the table below, Nos. 1, 9, 10, 16, 17, and 23 are comparative examples outside the present invention. For Nos. 1 to 9, the paint baking temperature was kept constant at 750℃, and the metal layer thickness was kept constant at about 0.5μ.
Ag components and Co, Fe, Sn, Mo, W, Mn, Zn, Cu
No. 1 has low adhesion strength to ceramic, while No. 9 has a different ratio of metal components.
Ni, Co, Fe, Sn metal components

【table】

【table】

[Table] When the amount increased, the adhesive strength and furthermore the dielectric properties deteriorated significantly. Nos. 2 to 8 show good characteristics, and Nos. 3 to 5 are particularly good. In addition, in the above table, Co, Fe, Sn, Mo,
In the component ratio columns for W, Mn, Zn, and Cu, enter the total amount of all metal components listed in 〓.
The ratio of each metal component may be set arbitrarily, and the point is that the total amount of metal components other than the Ag component may be within the range of the present invention. Nos. 10 to 16 are examples in which the baking temperature was changed, and the optimum temperature is No.
It was 13 or 14. Both the low temperature example No. 10 and the high temperature example No. 16 have low dielectric properties and low adhesive strength. Nos. 17 to 23 have different thicknesses of the metal layers after baking, and No. 17 is not preferred because it has extremely low adhesion to ceramics and the dielectric loss tangent deteriorates after life. With the thick film of No. 23, the amount of plating deposited is extremely large, making it difficult to obtain the dimensional accuracy as designed, which is undesirable. When mass producing porcelain capacitors, the allowable range of capacitance value is determined according to the grade of EIA and JIS standards, and reproducibility and yield are significantly better within the determined range than those that simply have high characteristic values. Productivity is good, and the present invention also reduces thickness.
It exhibits stable characteristics within the range of 1.5μ to 0.1μ. In addition, Nos. 1 to 23 have Ag components and Cu
Regarding the composition ratio of the components, Nos. 24 to 27 are examples using other metal powders, and all of them show good characteristics. As described in the above examples, the ceramic electronic components obtained by the present invention can be easily locally plated on ceramic substrates, are significantly cheaper than conventional baked silver electrodes, and have excellent characteristics. It is also in good condition and can adequately cope with the current soaring price of precious metals.
Furthermore, it is a method for manufacturing ceramic electronic components of great industrial value, which is suitable for industrial mass production.

Claims (1)

[Claims] 1 Ag component is 99.5 to 55 wt%, Co, Fe, Sn, Mo,
An electrode material containing one or more of W, Mn, Zn, and Cu components in a ratio range of 0.5 to 45 wt%;
A mixed paint consisting of an organic binder is applied to the required locations on the ceramic substrate, and then heated at 350℃ to 880℃.
Heat treatment is carried out in the temperature range of 0.1~
Form a 1.5μ metal particle layer, then Pd, Pt, Rh,
A substitution treatment is performed to precipitate the metal on the metal particle layer in a solution containing at least one of Os, Ir, and Ru metal ions, and then a nickel or copper metal electrode is formed by electroless plating. A method of manufacturing a ceramic electronic component, characterized by: 2 Printable or sprayable paste contains 99.5 to 55wt% Ag, Co, Fe, Sn, Mo, W,
Using a mixed paint consisting of an electrode material containing one or more of Mn, Zn, and Cu components in a ratio range of 0.5 to 45 wt% and an organic binder, the surface is roughened by chemical or mechanical treatment. The coated ceramic substrate is coated so that the edge portion remains, and then heat treated at a temperature range of 350℃ to 880℃ to form a metal particle layer of 0.1 to 1.5μ on the substrate.
A substitution treatment is performed to precipitate the metal ions on the metal particle layer in a solution containing at least one of the metal ions Pd, Pt, Rh, Os, Ir, and Ru, and then electroless plating is applied to nickel. Or a method for producing ceramic electronic components, which comprises forming copper-plated metal electrodes.