JPH10303550A - Pretreatment liquid for plating using conductive polymer film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a conductive polymer film having good conductivity by composing pretreatment liquid, which is used before forming a conductive polymer film used for forming a metal layer on the inner wall of the hole of a printed wiring board having conductive circuit layers of more than both surfaces, of three components of an inorganic acid, sulphonic acid or its salt, and a solution containing a nonionic surface active agent. SOLUTION: Pretreatment liquid for plating using a conductive polymer film is composed of three components of an inorganic acid, such as sulfuric acid hydrochloric acid, and phosphoric acid, sulphonic acid or its salt, and a solution containing a nonionic surface active agent. Using the pretreatment liquid can form a uniform conductive polymer film having good conductivity on the surface of the insulating material on the inner wall of a through hole or non-through hole of a both-surface printed board or multi-layer printed board.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pretreatment liquid used before forming a conductive polymer film used for forming a metal layer on an inner wall of a hole in a printed wiring board having a conductive circuit layer having two or more conductive circuits.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 4-507480 and Japanese Patent Application Laid-Open No. 506125/1992 disclose a method for electrically connecting the inner wall of a hole when performing metal plating by electroplating the inner wall of the hole on both sides or a multilayer printed wiring board. As shown in the official gazette, instead of the conventional electroless copper plating, an organic monomer such as pyrrole, furan, thiophene or a derivative thereof is chemically oxidized and polymerized on the insulating surface of the inner wall of the hole to conduct the electroconductive process. A method has been proposed in which after forming a conductive polymer film, the inner wall of the hole is metallized by electroplating.

[0003] That is, for example, a hole is drilled in a predetermined portion of a printed wiring board on both sides or more, and then a cleaning activation step (desmear step) including polishing and cleaning, and further,
Soft etching process for roughening the surface of copper foil, conditioning process for removing oils and fats on the surface of the object to be plated, permanganic acid treatment process for forming a manganese oxide layer serving as a polymerization catalyst, organic monomer application process, oxidative polymerization process Thus, a conductive polymer film was formed on the surface of the insulator, and the inner wall of the hole was metallized by direct electroplating. Among them, in the oxidative polymerization step, as an oxidative polymerization agent of the organic monomer, for example, an inorganic acid such as sulfuric acid, hydrochloric acid, phosphoric acid or persulfate, hydrogen peroxide, ferric chloride, iron (III) such as ferric sulfate, etc. ) Salts and their mixtures are used.

[0004]

However, in the method of making the insulating surface of the penetrating or non-penetrating hole of the double-sided or multi-layer printed wiring board conductive by the above-mentioned oxidizing polymer, the formed conductive layer is not uniform. However, since the conductivity of the through or non-through holes varies, the thickness of the plated film in the holes after the electroplating becomes non-uniform, and further, the copper foil surface after the conductive treatment is oxidized. .

According to the present invention, a conductive polymer film having good conductivity is formed on an insulator surface on the inner surface of a hole of a double-sided or multilayer printed wiring board, and before forming a uniform plating film thickness in the hole after electroplating. It is intended to provide a processing solution.

[0006]

According to the present invention, there is provided a pretreatment liquid for plating using a conductive polymer film, which is used for forming a metal layer on the inner wall of a hole of a printed wiring board having a conductive circuit layer having two or more surfaces. A pretreatment liquid used before forming a polymer film, which is an aqueous solution containing an inorganic acid such as sulfuric acid, hydrochloric acid, phosphoric acid, and the like, a sulfonic acid or a salt thereof, and a nonionic surfactant.
It is characterized by consisting of components.

[0007]

DETAILED DESCRIPTION OF THE INVENTION As the inorganic acid used in the present invention, sulfuric acid, hydrochloric acid, phosphoric acid and the like can be used.
The range of ５０50% by volume is preferred. When the content is less than 0.1% by volume, the oxidative polymerization is insufficient, the conductivity is reduced,
If it exceeds 50% by volume, the effect is not improved and it is not economical.

The sulfonic acid or a salt thereof used in the present invention preferably has a molecular weight of 5,000 to 6,000,000 and a general formula represented by the following formula 1, specifically, polystyrene sulfonic acid, polystyrene sulfonic acid and the like. Sodium acid, potassium polystyrene sulfonate, ammonium polystyrene sulfonate, lithium polystyrene sulfonate and the like can be used.

[0009]

Embedded image

The content is preferably in the range of 0.1 to 100 g / l. If the content is less than 0.1 g / l, the object of the present invention will not be achieved. It is not economical without improvement.

As the nonionic surfactant used in the present invention, those having a general formula represented by the following formula 2 are preferable. Specifically, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene Oleyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether and the like can be used, and the content is 0.1 to 50 g.
/ L range is preferred. If the content is less than 0.1 g / l, the object of the present invention will not be achieved, and if it exceeds 50 g / l, the effect will not be improved and it will not be economical. Further, the processing temperature is preferably from 10 ° C to 30 ° C, and the processing time is preferably from 10 seconds to 5 minutes.

Embedded image

[0012]

【Example】

Example 1 A through-hole having a diameter of 0.6 mm was formed by drilling at a predetermined position of a glass epoxy copper-clad laminate in which copper foil (18 μm) was bonded on both sides. Next, after removing burrs by surface polishing, the substrate was treated with a soft etching solution containing 80 g / l of sodium persulfate and 20 ml / l of concentrated sulfuric acid at room temperature for 3 minutes. After sufficient washing with water, the plate was treated with 50 ml / l of a cleaner conditioner CLC-301 (trade name, manufactured by Hitachi Chemical Co., Ltd.) at 60 ° C. for 5 minutes.
After sufficient washing with water, the mixture was treated at 85 ° C. for 3 minutes with an aqueous solution of potassium permanganate at 60 g / l as an aqueous solution of permanganate. After that, wash enough water,
Then, after treatment with an organic monomer aqueous solution containing 1% of a thiophene derivative and about 1% of an emulsifier at 25 ° C. for 2 minutes, 1 g of sodium polystyrene sulfonate /
1, polyoxyethylene nonyl phenyl ether 3 g /
After treatment with an aqueous solution of 20 ml / l of sulfuric acid at 25 ° C. for 2 minutes to form a conductive polymer film on the insulator surface of the through hole, the resistance value of the through hole is measured and the copper foil surface is observed. did.

Example 2 The procedure of Example 1 was repeated except that the polymer was treated at 25 ° C. for 2 minutes with an aqueous solution consisting of potassium polystyrene sulfonate 2 g / l, polyoxyethylene octyl phenyl ether 5 g / l, and sulfuric acid 30 ml / l as the oxidative polymerization agent. The same treatment was performed, the resistance value of the through hole was measured, and the surface of the copper foil was observed.

Example 3 The procedure of Example 2 was repeated except that the polymer was treated at 25 ° C. for 2 minutes with an aqueous solution containing 5 g / l of ammonium polystyrene sulfonate, 3 g / l of polyoxyethylene octyl phenyl ether and 15 ml / l of sulfuric acid as the oxidative polymerization agent. The same treatment was performed, the resistance value of the through hole was measured, and the surface of the copper foil was observed.

Example 4 In Example 3, an aqueous solution containing 1 g / l of polystyrene sulfonic acid, 5 g / l of polyoxyethylene nonylphenyl ether and 5 ml / l of sulfuric acid as an oxidative polymerization agent was used at 25 ° C.
The same treatment was performed except that the treatment was performed for 2 minutes, the resistance value of the through hole was measured, and the surface of the copper foil was observed.

Comparative Example 1 In Example 4, 10 ml / l of sulfuric acid was used as an oxidative polymerization agent.
25 ° C. with an aqueous solution consisting of 10 g / l of sodium persulfate,
The same treatment was performed except that the treatment was performed for 2 minutes, the resistance value of the through hole was measured, and the surface of the copper foil was observed.

Comparative Example 2 In Example 4, as an oxidative polymerization agent, sulfuric acid 20 ml / l,
The same treatment was performed except that the treatment was performed at 25 ° C. for 2 minutes with an aqueous solution containing 5 g / l of ferric sulfate, the resistance value of the through hole was measured, and the copper foil surface was observed. Table 1 shows the results of Examples 1 to 4 and Comparative Examples 1 and 2.

[0018]

[Table 1] As shown in Table 1, the conductive polymer film formed with the pretreatment liquid of the example had better and more uniform conductivity than that of the comparative example.

[0019]

As described above, according to the present invention, a conductive polymer film having good and uniform conductivity is formed on the insulating surface of a through hole or a non-through hole of a double-sided or multilayer printed wiring board. It is possible to provide a plating pretreatment liquid using a conductive polymer film capable of being used.

Claims (2)

[Claims] 1. A pretreatment liquid used before forming a conductive polymer film used for forming a metal layer on an inner wall of a hole of a printed wiring board having a conductive circuit layer having two or more sides, comprising sulfuric acid,
Inorganic acids such as hydrochloric acid and phosphoric acid, and sulfonic acids or salts thereof,
A pretreatment liquid for plating using a conductive polymer film, comprising three components of an aqueous solution containing a nonionic surfactant. 2. A sulfonic acid or a salt thereof having a molecular weight of 500.
The conductive polymer film according to claim 1, wherein the general formula is represented by the following formula 1 and the nonionic surfactant is represented by the following formula 2 within a range of 0 to 6,000,000. Pretreatment solution for plating using. Embedded image Embedded image