JPH1112786A - Conduction treating liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a stable conductive film in the initial period of conduction and to rapidly complete a polymn. reaction by adhering a conductive monomer to an insulated surface, then constituting a conduction treating liquid to impart electrical conductivity by oxidation polymn. of this monomer of an org. acid or its salts and an inorg. acid and the conductive monomer. SOLUTION: The conductive monomer is composed of a monomer consisting of a 5-membered heterocyclic group contg. sulfur or nitrogen, for example, pyrrole, thiophene, furan or its deriv. The amt. thereof to be added is preferably in a range of 0.01 to 0.3 wt.%. While the inorg. acid is generally sulfuric acid, other examples thereof include hydrochloric acid, phosphoric acid, etc. The content thereof is in a range of 1 to 20 wt.%. The examples of the org. acid or its salts include p-toluenesulfonic acid or its salt, etc. The content thereof is preferably set in a range of 0.1 to 30 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a conductive film on the surface of an insulating material by utilizing the oxidative polymerization of a monomer by a chemical method. The present invention relates to an acidic conductive solution which can be advantageously used for forming a conductor in a hole.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open Nos. 5-506125 and 4-188696 disclose means for imparting conductivity to the inner wall of a through hole in advance in order to electroplate the inner wall of the through hole of an insulating substrate. As described above, a processing solution containing an organic monomer for forming a conductive polymer film by oxidative polymerization and a solvent or a solubilizing agent, such as pyrrole and N-methyl-2, instead of the conventional electroless plating.
-A method has been proposed in which a mixture with pyrrolidone is used to form a conductive polymer film on the surface of an insulator on the inner wall of a through-hole, and then to perform electrolytic copper plating.

For example, a predetermined area of an insulating substrate is drilled, followed by a cleaning activation step (desmear step) including polishing and cleaning, an etching step for roughening the copper foil surface, and a modification of the surface of the object to be plated. After conducting a conditioning process, a permanganic acid treatment process to form a manganese oxide serving as a polymerization catalyst, a process of applying an organic monomer to form a conductive polymer film, and an oxidative polymerization process, For example, copper plating is performed to form through holes in the insulating substrate. Among these steps, the oxidative polymerization step is a step of forming a conductive polymer on the surface of an insulator by a chemical reaction in an acidic solution containing an oxidizing substance using manganese oxide as a polymerization catalyst.

[0004]

However, in such a process, in the initial state (new solution) of the electroconductive treatment liquid, the conductivity of the film is not sufficient.
There has been a problem that a conductive solution must be used to some extent using a dummy.

An object of the present invention is to make it possible to form a film having a stable conductivity even at the initial stage of conductivity, and to complete the polymerization reaction in a short time.

[0006]

Means for Solving the Problems The electroconductive treatment liquid of the present invention causes a conductive monomer to adhere to an insulating surface, and thereafter,
The conductive treatment liquid for imparting conductivity by oxidative polymerization of the conductive monomer is made of an organic acid or a salt thereof, an inorganic acid, and a conductive monomer.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The conductive monomer of the present invention may contain a monomer comprising a sulfur or nitrogen-containing 5-membered heterocyclic group, for example, pyrrole, thiophene, furan or a derivative thereof. Addition amount is 0.01
The range is preferably from 0.3 to 0.3% by weight. The reason is 0.01
If the content is less than 10% by weight, a uniform conductive film cannot be obtained,
If the content exceeds 0.3% by weight, the life of the processing solution is reduced.

[0008] Among the basic components of the electroconductive treatment solution used in the present invention, the inorganic acid is generally sulfuric acid, but other examples include hydrochloric acid and phosphoric acid. The content is preferably in the range of 1 to 20% by weight, and if it is less than 1% by weight, a stable oxidation reaction cannot be performed, resulting in insufficient conductivity. When the content exceeds 20% by weight, the effect is not improved.
Not economic.

Further, examples of the organic acid or salts thereof used include p-toluenesulfonic acid or a salt thereof, and polystyrenesulfonic acid or a salt thereof. The content is preferably set in the range of 0.1 to 30% by weight, and if it is less than 0.1% by weight, it is difficult to form a uniform conductive film, and if it exceeds 20% by weight, it is not effective. It is not economical without improvement.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Basic composition of conductive treatment solution used in the present invention,
The conditions are shown below. 98% sulfuric acid 100 ml / l p-toluenesulfonic acid 150 g / l Temperature: 25 ± 1 ° C

Example 1 A glass-based epoxy resin copper-clad laminate of 60 × 100 m
m, length of 5mm by etching on both sides of 0.4mmt plate
0mm, width 1.5mm, 3mm, 5mm, 7.5mm,
10mm, 15mm, 20mm exposed resin part 7
Windows having different types of areas were formed, and immersed in a sodium persulfate solution (80 g / l) for 3 minutes to perform an etching treatment. Then, after washing thoroughly with water, conditioner CLD-100 (trade name, manufactured by Hitachi Chemical Co., Ltd.)
At 40 ° C. for 5 minutes for surface treatment. Next, after sufficient washing with water, it was immersed in a potassium permanganate solution (60 g / l) at 85 ° C. for 3 minutes to perform a surface treatment. Thereafter, the substrate was sufficiently washed with water, and immersed in a conductive monomer solution CAD-100 (trade name, manufactured by Hitachi Chemical Co., Ltd.) at room temperature for 2 minutes to give a monomer. Next, the obtained copper-clad laminate is immersed for 2 minutes in a conductive treatment solution obtained by adding 0.1 g / l of a thiophene derivative to the above-mentioned basic solution without washing with water, to form a conductive polymer film on the surface of the insulator. And the hue of the film was observed. Further, as a copper sulfate plating bath, copper sulfate pentahydrate 60 g / l, sulfuric acid 180
g / l, chlorine ion 50 ppm and brightener CG-12
Copper plating was performed at 2 A / dm2 for 5 minutes using a bath of 5 ml / l (trade name, manufactured by Meltex Co., Ltd.), and the deposition property of the plating was evaluated. When the conductive polymer film is not formed uniformly, not only the growth of the plated copper becomes uneven, but also the time until it is covered with the plated copper increases, It was evaluated that the width of the window to be shortened was evaluated.

Example 2 The same coating treatment was carried out except that 1 g / l of a thiophene derivative was added to the above-mentioned basic bath, and the hue and plating depositability of the coating were evaluated.

Comparative Example 1 The same treatment as in Example 1 was performed except that the new solution of the basic bath was used, and the hue of the film and the plating deposition property were evaluated.
Table 1 shows the results of Examples 1 and 2 and Comparative Example.

[0014]

[Table 1] Note) Symbol: ○ Completely covered △ Slightly incomplete covered × It takes time to be covered

As explained above, according to the present invention,
Conductive treatment liquid for thiophene or its derivative (new solution)
Can form a uniform conductive polymer film stably from the beginning, and in the case of through-hole plating, the plating coating speed is high and a conductive plating that can form a uniform plated copper A processing solution can be provided.

[0016]

As described above, according to the present invention, it is possible to form a film having stable conductivity even in the initial stage of conductivity, and to provide a conductive film capable of completing a polymerization reaction in a short time. A treatment solution can be provided.

Claims (2)

[Claims] 1. A conductive monomer is attached to an insulating surface,
Thereafter, a conductive treatment liquid comprising an organic acid or a salt thereof, an inorganic acid, and a conductive monomer, as a conductive treatment liquid for imparting conductivity by oxidative polymerization of the conductive monomer. 2. The conductive solution according to claim 1, wherein the conductive monomer is a monomer comprising a 5-membered heterocyclic group having sulfur or nitrogen.