JPS6115983A - Catalyst for electroless plating - Google Patents

Abstract

PURPOSE:To obtain a catalyst for electroless copper plating reducing the damage of an apparatus and preventing the occurrence of halo phenomenon by adding a complex obtd. by dissolving a compound of Pd, Ag, Cu or Ni in an amide. CONSTITUTION:One or more kinds of compounds selected among compounds of Pd (II), Ag ( I ), Cu ( I ), Cu (II) and Ni (II) such as PdCl2 are dissolved in an amide such as dimethylformamide, and the resulting complex is diluted with water, alcohol or the like to obtain an catalyst for electroless copper plating. When a body to be plated is successively immersed in the catalyst soln. and a reducing soln., metallic particles of Pd, Ag, Cu or Ni are formed on the surface of the body. The body is then immersed in an electroless plating soln. The pH of the catalyst soln. is 3-14, a plating apparatus is hardly damaged, and uniform plating is obtd. The inner layer circuit of a multilayered printed wiring board is not corroded.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a catalyst for electroless plating.

(Prior Art) Electroless plating such as electroless copper plating is widely used in the field of Indo wiring boards to form circuits on insulating substrates such as laminates. In this case, the surface to which electroless plating is applied is activated, that is, catalyst nuclei for electroless plating are formed. Copper ions and the like in the electroless plating solution precipitate and grow as metallic copper etc. around this catalyst nucleus, forming a copper film and forming a circuit. In order to activate the insulating substrate, fine particles of metallic palladium, metallic silver, metallic copper, and metallic nickel, which serve as catalysts for electroless plating, are formed on the surface of the insulating substrate. Conventionally, this metal, for example, for Pd, P d C1h +S ncl*”'> P d”'+
It is obtained through a reaction similar to Sncl 4, and therefore contains many impurities such as Sn and CJ. In addition, it uses a strongly acidic liquid, which can cause damage to equipment and halo phenomena in the inner layer circuits of multilayer circuits. I was doing things like that.

(Objective of the Invention) The object of the present invention is to minimize damage to the equipment during the activation process.
K provides a catalyst for electroless plating that does not cause the 4-phenomenon.
be.

(Structure of the Invention) The present invention includes a complex obtained by dissolving at least one compound of palladium (II), silver (I), copper (T), copper (II), and nickel (I[) in an amide. This is a catalyst for electroless plating.

As the amide, formamide, dimethylformamide, diethylformamide, dimethylacetamide, dimethylacrylamide, etc., and mixtures thereof are used.

Palladium (If), silver (I), copper (I), copper (II)
As nickel (II) and compounds, chlorides, fluorides, bromides, iodides, nitrates, sulfates, oxides, sulfides, etc. and mixtures thereof are used. Among these, chlorides are particularly preferred.

Amide Vc-enhanced palladium, etc. is dissolved to form a complex of amide/palladium, etc., and these complexes are diluted with water or alcohol to a concentration of 0.01 to 1.0%, pH 3 to 14, preferably PH 11.5 to 12. It is made into a solution of .5 and becomes a catalyst for electroless plating.

When an insulating substrate such as a ceramic laminate, a plastic molded product, a cover such as a plastic film, or a kimono is immersed in the above catalyst for electroless plating, and then immersed in a reducing solution,
Palladium, silver, copper, and nickel metal particles are generated on the surface of the plated object. Reducing solutions include formaldehyde, stannous chloride, and sodium borohydride (NaBH).
4') A solution of a reducing substance such as glucose in water, alcohol, etc. is used. The concentration is 0.01-10% preferably α
At 1-1%, it's out! 6 to 14 are preferred.

These reducing agents may be used alone or in combination, or stabilizers, sensitizers, etc. may be added as appropriate.

Electroless plating is performed by immersing the object to be plated, on which metal particles such as palladium have been produced in this way, in an electroless plating solution. As the electroless plating solution, a normal electroless plating solution for copper, nickel, etc. is used.

If the object to be plated is pretreated before being immersed in the electroless copper plating catalyst of the present invention containing an amide/palladium complex or the like, the plating activation effect will be improved.

Such pre-treatment includes removing F4 with hydrogen peroxide or sulfuric acid.
13-6 hydrogen peroxide solution with a concentration of 0.1-10%, 1
1 (3-6 hydrochloric acid, 3-6 sulfuric acid, bisphenol A
An epoxy resin solution prepared by dissolving a type of epoxy resin in water, alcohol, or methyl ethyl ketone at a concentration [L1 to 10%] or the above-mentioned reducing solution is used.

Example 1 Double-sided copper-clad glass/epoxy laminate (thickness 1°6ff1
m) After drilling and cleaning, soak in dimethylformamide for 2 hours.
．． A solution containing 0% PdC6z (wt%, same hereinafter) was diluted with water, and the solution containing 0.1% PdCl 2 was treated for 5 minutes, drained, and then washed with 1% sodium hydroxide. Add 1 part of sodium borohydride (NaBH4) to the solution.
The substrate was immersed for 5 minutes while rocking in a solution in which the substrate was dissolved, and then immersed for 20 minutes in an electroless copper plating solution CUST-201 (manufactured by Hitachi Chemical Co., Ltd., part name) for rinsing. With electroless steel plating, copper was deposited uniformly in the holes of the glass poxy printed circuit board, and no halo phenomenon was observed.

Example 2 Double-sided copper clad paper/epoxy laminate (thickness 1.6m111)
Drilled and cleaned.

Then 1.0% sodium borohydride (NaBH4)
1% sodium hydroxide aqueous solution for 30 seconds.

Next, a solution of 1% PbCl2 in formamide was added to 0.
．． Dissolved in 3% sodium hydroxide aqueous solution [105% Pb (referred to as Jz solution). Immerse the substrate in the bath preparation solution for 5 minutes and shake well. Next, drain the liquid and add α1% hydroxide. 1.0% sodium borohydride (
The substrate was treated for 3 minutes in a reducing solution containing NaBHL), immersed in an electroless copper plating solution CUST-201 (manufactured by Hitachi Chemical Co., Ltd.) for 20 minutes, and then rinsed with water.

In electroless steel plating, copper was deposited uniformly in the holes of the substrate, and there was no halo phenomenon (effects of the invention).The following effects are achieved in the present invention.

(I) Since the field of electroless plating catalyst is 6 to 14,
There is little damage to the plating device.

(2) Uniform plating can be obtained.

Claims (1)

[Claims] 1. Palladium (II), silver (I), copper (I) in amide
A catalyst for electroless plating comprising a complex obtained by dissolving at least one of a compound of copper (II), copper (II), and nickel (II).