JPS5948950B2 - Active metal material paste for electroless plating and plating method using it - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal material paste for base activation of electroless plating on ceramic materials that is easy to manufacture, inexpensive, and has stable properties, and a plating method using the paste.

Conventionally, Ag. Ag-Pd. Ag1Pt. Ag-Ni
Baked electrode methods using precious metals such as , 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 and copper electrodes as metal electrodes by electrolytic plating, but with this method, the surface of the baked metal layer is rough and many small Due to the presence of the holes, the plating liquid penetrates into the small holes during the plating process, resulting in a disadvantage of deteriorating the adhesion strength between the fired metal layer and the porcelain body. Another method used is electroless plating,
It was common for electroless nickel metallization to first undergo a catalytic activation treatment through a chemical reaction between tin chloride and palladium chloride. However, there are many problems when used as electrodes for ceramic electronic components. That is, depending on the type of electrode material and related materials and the mounting method, tensile strength (reduced to 1/2 compared to silver-baked electrodes), electrical properties (deterioration of properties due to 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 dielectric breakdown is likely to occur due to concentration of the electric field at the peripheral edge of the electrode, so the thickness of the substrate cannot be made very thin. It was hot. In addition, 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.
There are various methods such as activating the porcelain surface, removing the plating resist, and then applying electroless plating to form a metal layer on the porcelain surface, vacuum evaporation method, photo etching method, etc., but none of them are suitable for ceramics. Satisfactory results cannot be obtained as electrodes for electronic components. In other words, the adhesion of plating is poor with conventional plating methods, and in particular, the thickness of capacitor products aimed at miniaturization is 0.1
It is as thin as ~0.3 mm, and has various shapes ranging from 4.5 to 16 φ, making it difficult to mass-produce it. Furthermore, in order to obtain as much capacitance as possible, if electrodes are formed on the entire surface, as mentioned above, the life characteristics will be extremely poor, and from the standpoint of reliability, it is necessary in the design to provide an edge around the electrode part on the porcelain surface. It was hot. The present invention provides a plating base active metal material paste that can be easily attached to required locations on ceramic materials by a new method different from the conventional electroless plating method as described above, and a plating method using the paste. .

That is, the present invention uses a metal varnish made by completely dissolving a silver compound in a solvent as a base active metal for electroless nickel or copper plating on ceramic materials such as dielectrics, semiconductors, piezoelectrics, and insulators. 0.05 in terms of metallic silver component in one or more vehicles of fat-soluble, water-soluble, amphoteric resins such as base derivatives, rubber derivatives, vinyl derivatives, etc.
~30 Wt% is dispersed to form an electroless plating base active metal material paste, and the paste is applied to the required areas of the ceramic material by screen printing, spraying or other methods, and then heated at a temperature of 350°C to 850°C. Apply baking treatment within the range and then perform electroless copper plating, or
Or Pd. Pt. Rh. Os. It is characterized by performing a substitution treatment in a solution containing at least one of Ir and Ru ions, and then performing electroless nickel or copper plating, and is obtained by the method of the present invention. The electrode has superior properties such as adhesive strength and electrical properties compared to those obtained by conventional chemical reduction plating methods.

An embodiment of the present invention and reasons for limitation will be described below.

The method for preparing the active paste for electroless plating is A.
Using a silver compound such as gNO3, AgNO2, Ag2SO4, AgCN, etc., using a solvent such as H2O or butyl carbitol, turpine oil, or ethyl alcohol, and using a resin such as ethyl cellulose, cellulose succinate, butyl rubber, or polyvinyl butyral as an organic binder. , the metal component is 0.05 to 30 wt%, the resin component is 1 to 10 wt%, and the remainder is a solvent component, and the viscosity is about 30,000 to 60,000 C for screen printing.
The PS was adjusted to have a viscosity of about 100 to 400 CPS for spraying, and was used to form a base activation paste for electroless plating on ceramic materials.

In order to improve the dimensional accuracy of screen printing, it is possible to significantly improve the printing accuracy by adding a carbon component within the range of 0.1 to 30 wt%. Conventional silver paste has a metal content of 80wt% or more, so there is no sagging during printing, but when the resin content increases, sagging occurs, so this is the best way to prevent this. There is an effect. Note that the effect is weak up to 1 Wt%, and 3
If it exceeds 0 wt%, the carbon component will not be completely dispersed during baking and the carbon component will remain, which will adversely affect electrical properties, etc., which is not preferable. In addition, instead of the carbon component, it is also effective to add CacO3, SiO2, MgO, clay powder, etc. having a particle size of 2 microns or less as an inorganic raw material. Next, as a method of using ceramic materials, a BaTlO3-BaZrO3-CaTiO3-based element body is used as a dielectric ceramic substrate used for electronic parts, and the thickness is 0.15 mm to 2 mm and the shape is 4 to 20 φ.
Using a spraying and printing method using a mask that leaves a 0.5 mm edge on both sides of the element, the temperature is 80°~ after coating.
After drying at a temperature of 100°C to evaporate the solvent, baking is performed using an electric furnace at a temperature range of 350 to 850°C to precipitate metal silver particles.

The necessity of baking between 350° and 850°C is to form a strong metallic silver particle layer on the surface of the ceramic substrate; at temperatures up to 350°C, resin components remain and Ni. Cu
If the temperature exceeds 850° C., the silver particles will melt, which is not preferable. Then Pd. Pt. Rh, 0
s. Ir. Substitution treatment was performed for 1 minute in a solution containing 0.05 wt% Ru ions, and after washing with water, the Ni plating was made using nickel sulfate containing sodium hypophosphite (or hydrazine, boron hydride compounds, etc.). A nickel film is formed by immersing it in a plating solution, and a copper film is formed using copper sulfate as Cu plating, formalin as a reducing agent, Rothsel salt as a complexing agent, and sodium hydroxide as an alkaline agent. I did this. The active metal material for electroless plating of the present invention can fully exhibit its function as long as the particle layer of metallic silver is 1 μm or less, and when used as a capacitor electrode, it cannot be used as a conventional material for a layer of metal silver of 1 μm or more. Compared to baked silver (silver thickness: 5 μm to 20 μm), it has no features in terms of price, and is undesirable because Ag ion migration occurs particularly in the humidity load life characteristics.

In addition, in the present invention, the metal silver particle layer after paste baking is plated with electroless Cu or Pd
lPt. ．． RhlOs. Ir. At least one Ru ion
Electroless Ni.Cu after precipitating metal ions (including seeds)
By plating, it functions as an electrode.

Baked silver, which has conventionally been used as an electrode material for capacitors, has a thick film thickness of 3 to 20 μm after baking, and the film layer itself can be used as an electrode layer. The metallic silver particle layer is extremely thin, less than 1μ, and does not function as an electrode by itself, nor can it be soldered, etc., and cannot be used for subsequent electroless Cu plating deposition or Pd. Pt. Rh, 0s. Ir. After Ru ion precipitation, electroless Ni. Only by Cu plating can it be used as an electrode function, and can it also be soldered. Although this implementation has been described only for dielectric ceramic materials, it can also be applied to other piezoelectric materials, insulators, glass, semiconductors, etc.
There is no problem at all as long as the ceramic material can withstand temperatures above .degree. C., and it is a new method of forming a plating base that is completely different from the conventional immersion electroless plating method, and it is particularly effective when used for local plating.

Claims (1)

[Claims] 1. A metal varnish made by completely dissolving a silver compound in a solvent, and one or two of a fat-soluble resin, a water-soluble resin, and an amphoteric resin.
Dispersed in a vehicle of more than 0.05% as a metal component
An electroless plating base active metal material paste containing 30% by weight. 2 A metal varnish made by completely dissolving a silver compound in a solvent is mixed with one or two of fat-soluble resins, water-soluble resins, and amphoteric resins.
Dispersed in a vehicle of at least 0.05% as a metal component
~30% by weight and additionally 0 carbon powder
．． An electroless plating base active metal material paste containing 1 to 30 percent by weight. 3 A metal varnish made by completely dissolving a silver compound in a solvent is mixed with one or two of fat-soluble resin, water-soluble resin, and amphoteric resin.
Dispersed in a vehicle of more than 0.05% as a metal component
An active metal material paste for electroless plating, which contains 30% by weight and further contains 2% by weight or less of an inorganic raw material having a powder particle size of 2μ or less. 4 A metal varnish made by completely dissolving a silver compound in a solvent is mixed with one or two of fat-soluble resin, water-soluble resin, and amphoteric resin.
Dispersed in a vehicle of more than 0.05% as a metal component
Applying an electroless plating base active metal material paste containing 30 weight percent to the ceramic material,
A plating method characterized by performing a baking treatment within a temperature range of 0 to 850°C to precipitate metal fine particles, and then performing electroless copper plating. 5 A metal varnish made by completely dissolving a silver compound in a solvent is mixed with one or two of fat-soluble resins, water-soluble resins, and amphoteric resins.
Dispersed in a vehicle of more than 0.05% as a metal component
30% by weight and additionally 0.3% by weight of carbon powder.
Applying an electroless plating base active metal material paste containing 1 to 30 weight percent of the paste to the ceramic material;
A plating method characterized by performing a baking treatment within a temperature range of 50 to 850°C to precipitate metal fine particles, and then performing electroless copper plating. 6 A metal varnish made by completely dissolving a silver compound in a solvent is mixed with one or two of fat-soluble resins, water-soluble resins, and amphoteric resins.
Dispersed in a vehicle of more than 0.05% as a metal component
An electroless plating base active metal material paste containing 30% by weight and further adding 2% by weight or less of an inorganic raw material having a powder particle size of 2 μ or less is applied to the ceramic material, and the paste is applied within a temperature range of 350 to 850°C. A plating method characterized by performing a baking treatment to precipitate fine metal particles, and then performing electroless copper plating. 7 A metal varnish made by completely dissolving a silver compound in a solvent is mixed with one or two of fat-soluble resins, water-soluble resins, and amphoteric resins.
Dispersed in a vehicle of more than 0.05% as a metal component
Applying an electroless plating base active metal material paste containing 30 weight percent to the ceramic material,
Baking treatment is performed within a temperature range of 0 to 850°C to precipitate metal fine particles, and then Pd, Pt, Rh, Os, I
Replacement treatment is performed in a solution containing at least one of r and Ru ions, followed by electroless nickel plating,
A plating method characterized by performing any of electroless copper plating. 8 A metal varnish made by completely dissolving a silver compound in a solvent is mixed with one or two of fat-soluble resins, water-soluble resins, and amphoteric resins.
Dispersed in a vehicle of more than 0.05% as a metal component
30% by weight and additionally 0.3% by weight of carbon powder.
Applying an electroless plating base active metal material paste containing 1 to 30 weight percent of the paste to the ceramic material;
Baking treatment is performed within a temperature range of 50 to 850°C to precipitate metal fine particles, and then Pd, Pt, Rh, Os,
A plating method characterized by performing a substitution treatment in a solution containing at least one type of Ir and Ru ions, and then performing either electroless nickel plating or electroless copper plating. 9 A metal varnish made by completely dissolving a silver compound in a solvent is mixed with one or two of fat-soluble resins, water-soluble resins, and amphoteric resins.
Dispersed in a vehicle of more than 0.05% as a metal component
An electroless plating base active metal material paste containing 30% by weight and further adding 2% by weight or less of an inorganic raw material having a powder particle size of 2 μ or less is applied to the ceramic material, and the paste is applied within a temperature range of 350 to 850°C. Baking treatment is performed to precipitate metal fine particles, and then Pd
, Pt, Rh, Os, Ir, and Ru ions are subjected to substitution treatment in a solution containing at least one kind of ion, and then either electroless nickel plating or electroless copper plating is performed. plating method.