JPS634335B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for easily and inexpensively manufacturing ceramic electronic components with stable properties. Conventionally, electrodes of ceramic electronic components that utilize the functional characteristics of dielectric elements, piezoelectric elements, semiconductor elements, etc. have been made using Ag, Ag-Pd, Ag-
Baked electrodes mainly made of noble metals such as Pt and Ag-Ni are used. However, with the recent rise in the price of precious metals, various methods of forming electrodes by plating are being developed. However, these methods also have many drawbacks. For example, it is possible to form a baked silver electrode containing glass frit on the surface of a ceramic body, and then form a nickel electrode or a copper electrode by electrolytic plating or the like.
In this method, since the surface of the baked metal layer is rough and has many small pores, the plating liquid penetrates into the small pores during the plating process, resulting in the adhesion of the baked metal layer and the ceramic body. It had the disadvantage of deteriorating strength. Another method used is the electroless nickel plating method, which generally involves first reacting tin chloride and palladium chloride to subject the surface of the element to a catalytic activation treatment. However, this method has many problems when used as electrodes for ceramic electronic components. In other words, not only does the tensile strength decrease depending on the type and mounting method of the electrode material and related materials (reduced to 1/2 compared to a silver-baked electrode), but also the product characteristics etc. It deteriorated rapidly. For example, in the method of electroless nickel plating on a ceramic electronic component body, due to the nature of the method, nickel is likely to be formed on the entire circumferential surface of the substrate, and in that case, the plating film on the circumferential side is ground away to form a counter electrode. However, the creepage withstand voltage distance is determined by the thickness of the substrate, and dielectric breakdown is likely to occur due to concentration of the electric field at the peripheral edge of the electrode, making it impossible to make the substrate very thin. Furthermore, instead of these methods, it is also possible to use a partial plating method. When forming a metal layer with a desired pattern on the surface of a ceramic body, a plating resist is applied to the required locations on the surface of the ceramic body in advance.
This method then activates the surface, removes the plating resist, and then performs electroless plating to form a metal layer on the surface of the ceramic body. There are various other methods such as vacuum evaporation and photoetching, but none of these methods has been able to produce satisfactory results as electrodes for ceramic electronic components. In other words, with conventionally known plating methods, the adhesion of the plating is poor;
In particular, if we take a capacitor as an example, the thickness of the capacitor body for the purpose of miniaturization is 0.1 to 0.3 mm.
It is thin and varies in diameter from 4.5 to 16 mm, making it difficult to implement when considering mass production. Furthermore, in order to obtain as large a capacitance value as possible, if electrodes were formed on the entire two opposing surfaces of the element body, the life characteristics would be extremely poor as described above, and there would be many problems in terms of reliability. Ta. The present invention eliminates many of the drawbacks of the conventional methods and provides a method for manufacturing ceramic electronic components with significantly stable life characteristics. That is, in the method of the present invention, a paste containing one or more of compounds such as Co, Ni, and Fe is applied to necessary localized areas of a ceramic substrate, and then baked at a temperature within the range of 350 to 900°C, and then, Co, Ni, Co, Ni,
A substitution treatment in which particles of Fe metal or its alloy are precipitated, and then the surface of the metal or alloy is replaced with at least one of Pd or Pt in a solution containing at least one of Pd or Pt ions. Then, electrodes of nickel, cobalt, and copper are formed by electroless plating. The electrode obtained by this method has very good characteristics and can provide sufficient functionality. The method of the present invention will be described below with reference to Examples. First, BaTiO ₃ − was used as a ceramic substrate.
A BaZrO ₃ -based dielectric ceramic body was used. Its thickness is 0.3mm and diameter is 12mm. The paste was applied by spraying or printing using a mask that left edges (edges) of 1 mm on both sides of this substrate. In addition, for the purpose of improving the adhesive strength and characteristics between the ceramic surface and the electrode, it is also a good method to roughen the ceramic surface by chemical treatment or mechanical treatment in advance. Note that pastes containing Co, Ni, and Fe compounds include nitrates, acetates, oxalates, and naphthenates of Co, Ni, and Fe, and organic compounds such as amide, phenolic, and cellulose. Using a binder component, a solvent such as ethyl cellosolve, butyl carbitol, or alcohol, the viscosity is 40,000C/S/P for printing, and the viscosity is 100~100 for spraying.
It was made by adjusting to 300C/S/P. The components are 0.01 to 7.5% by weight of the metal component, 3 to 35% by weight of the organic binder component, and 70 to 7.5% of the solvent component.
It is 97% by weight. This was applied to the front and back surfaces of a ceramic substrate in a film thickness of 1 to 15 μm. Then 80~300℃
After drying at a temperature of 350 to 900 using an electric furnace,
Baking at a temperature within the range of 350-900 °C in a non-oxidizing atmosphere,
Formed fine particles of Co, Fe, Ni metals or alloys. Thereafter, a substitution treatment was performed with a solution containing 0.01% Pd or Pt ions, and then immersed in a plating solution containing nickel sulfate and sodium hypophosphite to form a nickel film. In addition, Pd or Pt
Solutions were prepared by dissolving PdCl ₂ or H ₂ PtCl ₆ .6H ₂ O in HCl, water, or alcohol, and further diluting with water. Next, lead wires were attached using a dipping method using a solder material mainly based on Sn--Pb, and then impregnated with a phenol-based coating resin and wax to obtain a finished product. In the present invention, it is necessary to apply a paste containing components of Co, Ni, and Fe compounds and then heat treat it in a non-oxidizing atmosphere. This is to form fine particles. Also, it is preferable to bake at a temperature within the range of 350 to 900 degrees Celsius, because at temperatures lower than 350 degrees Celsius, resin components will remain, making it difficult to form a metal electrode uniformly and reducing its adhesive strength. This is because the temperature is higher than 900° C., which is not preferable because the dielectric properties and life characteristics deteriorate. After precipitating Co, Ni, and Fe metal or alloy particles by heat treatment, 0.0005 to 3% by weight is added.
If the substitution treatment is performed in a solution containing Pd or Pt compounds within the above range, no substitution treatment or substitution treatment outside the above range will cause the subsequent electroless plating of Ni, Co, Cu, etc. to rise slowly and uniformly. This is because it is difficult to obtain a plating film with good quality, the dielectric properties and other properties are poor, and large variations occur. In the above explanation, nitrates, acetates, oxalates, naphthenates, etc. as compounds of Co, Ni, and Fe were used, but other compounds may be used as long as they remain as a metal fine particle layer after baking. There is no problem even if it is. In addition, after forming the metal fine particle layer, Pd,
By Pt substitution and electroless plating, nickel, copper,
After forming the cobalt electrode, the adhesive strength can be increased by performing heat treatment at a temperature within the range of 200 to 400°C. Furthermore, by using a ceramic substrate whose surface has been roughened by chemical treatment with diluted hydrofluoric acid or by mechanical treatment,
It was possible to increase the adhesion strength of the plating film. The Nickelmetski method uses a reducing agent to precipitate nickel metal from nickel ions,
In addition to sodium hypophosphite, a boron hydride compound can be used as the reducing agent. Additionally, terminal attachments such as lead wires contain phosphorus components.
The Ni plating surface has a Pb component of 50% to 75% and a Sn component of
It is sufficient to use a solder material with a high Pb component of 50% to 25%, and the Ni plating surface containing a boron component should have a Pb component of 50 to 25% and a Sn component of 50 to 75%.
A solder material with many components may be used. For copper plating, for example, copper sulfate may be used as a metal salt, formalin as a reducing agent, EDTA as a complexing agent, and sodium hydroxide as an alkali agent. The table below shows a comparison of Examples and Comparative Examples of the method of the present invention. The dielectric constant ε and dielectric loss tangent tan δ as dielectric properties in the table are 1KHz at a temperature of 20℃.
The life test was conducted under the conditions of applying a DC voltage of 1000V for 1000 hours in a high-temperature, high-humidity atmosphere with a temperature of 85°C and a relative humidity of 85%.

【table】

[Table] In the above table, sample No. 1, 8, 9, 14, 15,
Nos. 19 and 20 are comparative examples outside the scope of the present invention. Sample No.
In Nos. 1 to 8, the baking temperature was kept constant at 600°C and the content of nickel nitrate was varied. As is clear from the table, Samples Nos. 2 to 7 exhibit good properties, and Samples Nos. 4 and 5 in particular exhibit extremely good properties even after the life test. Samples No. 9 to 14 contained 1.5% by weight of nickel nitrate.
Examples within the scope of the present invention, in which the baking temperature is kept constant and the baking temperature is varied, are very good. Samples Nos. 15 to 21 were samples in which the content of palladium chloride in the replacement treatment solution was changed, and the characteristics were improved by treatment with a replacement solution containing palladium chloride within the range of the present invention. In addition, PbTiO ₃ −PbZrO ₃ based piezoelectric materials,
The method of the present invention also showed good characteristics for BaTiO ₃ -based semiconductor materials. In this way, compared to conventionally used silver-baked electrode materials, the electrodes obtained by the method of the present invention are completely comparable, especially in terms of price, which is less than 1/20, and in terms of characteristics. It is extremely stable, and the method of the present invention is suitable for industrial mass production and has great industrial value.

Claims (1)

[Claims] 1. Ni in the range of 0.01 to 7.5% by weight in terms of metal components in a printable or sprayable resin paste;
A paste containing at least one component of Fe, Co compounds is used, and after being applied onto a ceramic substrate, it is baked at a temperature in the range of 350 to 900°C, and then heated at a temperature in the range of 350 to 900°C in a non-oxidizing atmosphere. Heat treatment is performed at a temperature within a range to precipitate particles of at least one metal or alloy of Ni, Fe, and Co, and further, at least one of Pd or Pt in a range of 0.0005 to 3% by weight calculated as a metal component. The surface of the above metal or alloy is coated with Pd or Pt in a solution containing a compound of
1. A method of manufacturing a ceramic electronic component, which comprises performing a substitution treatment to replace at least one of the following, and then forming a metal electrode by an electroless plating method. 2. A method of manufacturing a ceramic electronic component according to claim 1, characterized in that a ceramic substrate whose surface has been roughened by chemical treatment or mechanical treatment is used.