JPS631728B2 - - 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., materials such as Ag, Ag-Pd, Ag-Pt, and Ag- that contain glass frit on the surface of the ceramic body have been used. A baked electrode method using precious metals such as Ni has 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 electroless plating, 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. i.e. types of electrode materials and related materials;
Depending on the mounting method, the tensile strength (reduced to 1/2 compared to a silver-baked electrode), electrical properties (deterioration of properties by life test), etc. 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 yield satisfactory results as electrodes for ceramic electronic components. I can't. In other words, the adhesion of the plating with conventionally known plating methods is poor, and for example, in the case of capacitors, the thickness of the capacitor product, especially for miniaturization, is 0.1.
It is as thin as ~0.3mm and has various shapes ranging from 4.5 to 16φ, making it difficult to mass-produce it. 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, a paint containing 99.5 to 0.5 wt% of Ag and 0.5 to 99.5 wt% of Ni is applied to necessary parts of a ceramic substrate for dielectrics, piezoelectrics, semiconductors, etc., and then heated at 300°C to 800°C. Heat treatment is performed at a temperature range of
The method of the present invention is characterized by performing a substitution treatment in a solution containing at least one type of metal ion among the above, 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. First, Pb (Mg1/3Nb2/3) is used as the piezoelectric substrate.
O ₃ −PbTiO ₃ −PbZrO ₃ series, thickness 0.5mm, shape 12φ
element as a dielectric ceramic substrate.
A BaTiO ₃ -BaZrO ₃ -CaTiO ₃ element with a thickness of 0.15 mm and a shape of 6.5 φ was used, and a substrate whose surface was roughened by nitric acid treatment was used. A spraying or printing method was used using a mask that left a 1 mm edge (end surface). In addition, the method for creating paint with Ag-Ni components is as follows:
Using 0.2μ Ag powder and 0.5μ Ni powder, metal components are approximately 3 to 40 wt%, resin organic binders such as cellulose and acrylic are approximately 3 to 15 wt%, turpentine oil, butycarbitol acetate, and ethyl cell. Using about 82 to 57 wt% of solvent components such as Solve, the viscosity for printing (about 30,000 to 60,000 CPS) was adjusted to the one for spraying (about 100 to 400 CPS), and was applied to the front and back surfaces of ceramic substrates. Although the metal powder used had a particle size of 0.5μ, it differs slightly depending on the application, such as for screens and spraying, but there is no problem as long as the average particle size is 7μ or less. Thereafter, after drying at a temperature of 80° C. to 100° C. to evaporate the solvent, baking was performed using an electric furnace at a temperature range of 300° C. to 800° C. to form a metal fine particle layer. The necessity of baking between 300°C and 800°C is to form a strong metal layer on the ceramic substrate surface. If the heat treatment temperature is below 300°C, the organic substances will not be completely scattered, and the nickel, Electroless plating of copper, etc. becomes incomplete and tensile strength decreases. Further, in terms of electrical characteristics, the loss angle is deteriorated, which is not preferable. At temperatures above 800°C, the metal components oxidize, making plating difficult. Further, the electrical characteristics are also deteriorated, which is not preferable. After that, substitution treatment was performed for 1 minute in a solution containing 0.05wt% of Pd, Pt, Os, Ir, Ru metal ions, and for Ni plating, nickel sulfate was replaced with sodium hypophosphite (or hydrazine, boron hydride). A nickel film was formed by immersing it in a plating solution containing a chemical compound, etc.). Electroless plating of copper was carried out using copper sulfate as the copper plating, formalin as the reducing agent, Rothsiel's salt as the complexing agent, and sodium hydroxide as the alkaline agent. still
After baking the Ag-Ni component base active metal at a temperature within the range, apply 1 of organic acid, ammonia water, nitric acid, and sulfuric acid solution.
After being immersed in the seed or mixed solution for about 1 minute, Pd,
When immersed in a metal ion solution of Pt, Os, Ir, or Ru, the dimensional accuracy of plating can be improved and the adhesion of plating to unnecessary parts can be prevented. Incidentally, in the Ag-Ni component, if the ratio of Ag component is 99.5% or more and Ni component is 0.5% or less, the adhesive strength between the substrate and the plating decreases, which is not preferable. Also, if the Ag content is less than 0.5% and the Ni content is more than 99.5%, an oxide film is likely to form, making plating difficult.
This is not preferable because the electrical properties deteriorate and the adhesive strength with the substrate also decreases. In the present invention, the metal particle layer after baking the paste is 1.5μ or less (not including 0).
Pd, Pt, Os, Ir, Ru metals are precipitated, and
The function as an electrode is achieved for the first time by electroless plating with Ni, Cu, etc. It should be noted that baked silver, which has been conventionally used as an electrode material for capacitors, needs to be formed with a thick film thickness of 3 to 20 μm after baking, and the film layer itself can be used as an electrode layer. The metal particle layer after baking is extremely thin, less than 1.5μ, and does not function as an electrode by itself, nor can it be soldered.After the subsequent metal precipitation of Pd, Pt, Os, Ir, and Ru, By plating with Ni and Cu, it can be used as an electrode for the first time, and it can also be soldered.
The present invention can fully exhibit its function as long as the metal particle layer after baking is present at a thickness of 1.5μ or less, and when used as an electrode for ceramic electronic components such as capacitors, the thickness is 1.5μ or more. In this case, the adhesive strength after plating decreases, and when electroless plating is applied, the plating adheres to areas other than the designated areas, and it is difficult to perform plating with high dimensional accuracy.Especially, the electrical properties deteriorate in the humidity load life characteristics. Significant.
Also, as the thickness increases, conventional baked silver (silver thickness 3~
Compared to 20μ), the features are weaker in terms of price. Although piezoelectric and dielectric ceramic materials have been described in this example, there is no problem with other insulators, semiconductor ceramics, and other ceramic materials that can withstand temperatures of 300°C or higher.
This is a method for manufacturing ceramic electronic components using a new plating method that is completely different from the conventional immersion electroless plating method. In the present invention, in order to improve the adhesive strength, a small amount (5wt% or less) of glass powder or a low melting point metal such as bismuth oxide, boric acid, or lead oxide with a melting point of 850°C or less is used as a sintering agent for the Ag-Ni component. Oxide or bismuth naphthenate, which becomes an oxide after firing, is also effective. In addition, when printing paint, conventional baking electrodes contain more than 50wt% of the total metal component, which makes it difficult for "sagging" to occur during printing, but in the present invention, the paint has a resin component. , Contains a large amount of solvent, and is more likely to sag than conventional products. To prevent these, a small amount (20wt% or less) of inorganic raw materials such as carbon powder and clay with a powder particle size of 2μ or less is used.
It is effective when added. Furthermore, addition of small amounts of Co, Cr, etc. in Ni and Cu electroless plating also has the effect of increasing hardness. The same effect can also be obtained by using a metal compound as a part of the Ag-Ni metal component. In addition, Cu, Zn,
It is also possible to improve plating adhesion by adding a small amount of metal powder such as Cr.

【table】

【table】

【table】

[Table] Table 1 shows the characteristics of capacitors using BaTiO ₃ -BaZrO ₃ -CaTiO ₃ -based dielectric ceramic.
Samples 10, 11, 17, and 24 are comparative examples outside the present invention. No.1
~10 are examples in which the ratio of Ag-Ni components was changed and the paint baking temperature was kept constant at 400℃, and the average thickness of the Ag-Ni metal layer after heat treatment was kept constant at 0.5μ. The adhesion of Ni plating becomes larger than the later designed dimensions, which is undesirable, and the adhesion strength with the ceramic substrate is weak, and the initial electrical characteristics are also low, and the deterioration of the characteristics is particularly significant after the life test. Ni like No.10
When using only the components, the adhesion of Ni plating was poor, and the tensile strength and dielectric properties were also extremely poor. No.2～
No. 9 shows good characteristics, especially No. 5, 6, and 7.
has excellent tensile strength. Nos. 11 to 17 are examples in which the baking temperature was varied, and the optimum temperature was around 350°C to 450°C. Both the low temperature example No. 11 and the high temperature example No. 17 have low dielectric properties and low adhesive strength. Nos. 18 to 24 are those in which the thickness of the metal layer after baking is changed, and the optimum thickness is around 0.3 to 0.8 μ, and when it becomes thick like No. 24, the adhesive strength is extremely reduced, which is not preferable. Sho No.
1 to 24 are examples in which Ni plating was applied, and the Ni plating thickness was approximately 1.5μ,
Generally speaking, there seems to be a relationship between Ni plating thickness and adhesive strength, but in the method of the present invention, almost no difference is observed, and a plating thickness of about 1 μm to 3 μm is sufficient. Nos. 25 to 27 are examples in which Cu plating was applied.
Although it shows slightly lower characteristics than Ni-metsuki,
There is no practical problem at all. Table 2 shows Pb(Mg1/3Nb2/3)O ₃ −PbTiO ₃ −
This is an example in which a PbZrO ₃ -based piezoelectric material is used, and Nos. 1, 10, 11, 17, and 23 are comparative examples outside the present invention, and Nos. 1 to 10 are the ratios of Ag-Ni components. These are examples in which the ratio was varied and other paint heat treatment temperatures, metal layer thickness, etc. were kept constant, and No. 1 had low tensile strength and electrical properties. In terms of characteristics, Nos. 5 and 6 show excellent values. No.
As shown in No. 10, the electrical properties and tensile strength are low when the Ni component is alone. Nos. 11 to 17 are examples in which the baking temperature was varied, and the optimum temperature was around 350°C to 450°C.
No.11 has extremely low tensile strength at low temperatures, and No.11 has extremely low tensile strength at low temperatures.
At a high temperature of 17, some of the underlying active metal melted, resulting in poor plating adhesion and poor properties.
Nos. 18 to 23 have different thicknesses of the metal particle layer after baking, and the optimal thickness is around 0.1 to 0.8μ.
If it becomes thicker, the tensile strength will drop significantly, which is not preferable. Note that Nos. 1 to 23 are examples in which Ni plating was applied, while Nos. 24 and 25 are examples in which Cu plating was applied, and although they show slightly lower characteristics than Ni plating, they are completely ineffective in practical use. No problem. As described in the examples above, the ceramic electronic components obtained by the present invention can be easily plated on the required portions of the ceramic substrate, and are significantly cheaper in price than conventional baked-on 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 0.5 wt%, Ni component is 0.5 to 0.5 wt%.
A mixed paint consisting of an electrode material within a ratio range of 99.5wt% and an organic binder is applied to the required locations on a ceramic substrate, and then heat treated in a temperature range of 300℃ to 800℃ to form a coating of 1.5μ or less on the substrate. A metal particle layer is formed, and then a substitution treatment is performed to precipitate the metal on the metal particle layer in a solution containing at least one metal ion among Pd, Pt, Os, Ir, and Ru, and then no Method 2 for manufacturing ceramic electronic components characterized by forming nickel or copper metal electrodes by electrolytic plating method 2 After heat treatment at 300°C to 800°C, the ceramic electronic parts are heated in one or a mixed solution of organic acid, aqueous ammonia, nitric acid, and sulfuric acid. A method of manufacturing a ceramic electronic component according to claim 1, which comprises immersion. 3. Claim 1, characterized in that a paste containing 5 wt% or less of glass powder and a low-melting metal oxide (including those that become oxides after sintering) with a melting point of 850°C or less is used as a sintering agent. 2. Method for manufacturing ceramic electronic components as described in Section 1. 4 20wt% inorganic raw materials with powder particle size of 2μ or less
2. A method of manufacturing a ceramic electronic component according to claim 1, characterized in that the following paste is used. 5 Using a mixed paint consisting of an electrode material with a ratio of 99.5 to 0.5 wt% Ag and 0.5 to 99.5 wt% Ni and an organic binder in a paste that can be printed or sprayed, chemical treatment or mechanical Pt is coated on a ceramic substrate whose surface has been roughened by surface treatment so that the edge portion remains, and then heat treated in a temperature range of 300℃ to 800℃ to form a metal particle layer of 1.5μ or less on the substrate. Pd, Os, Ir, Ru
A substitution treatment is performed to precipitate the metal on the metal particle layer in a solution containing at least one kind of metal ion, and then a nickel or copper metal electrode is formed by an electroless plating method. A method for manufacturing ceramic electronic components. 6. The method for producing ceramic electronic components according to claim 5, which comprises immersing the ceramic electronic component in one or a mixed solution of organic acid, aqueous ammonia, nitric acid, and sulfuric acid after heat treatment at 300°C to 800°C. 7. Claim 5, characterized in that a paste containing 5wt% or less of glass powder and a low-melting metal oxide (including those that become oxides after firing) with a melting point of 850°C or less is used as a sintering agent. 2. Method for manufacturing ceramic electronic components as described in Section 1. 8 20wt of inorganic raw material with powder particle size of 2μ or less
6. The method of manufacturing a ceramic electronic component according to claim 5, characterized in that a paste containing % or less is used.