JP2002309376A - Catalyst impartation method for electroless copper plating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst impartation method for electroless copper plating capable of forming an electroless plating film having a good appearance and an adhesion property without using expensive noble metals as catalytic metals. SOLUTION: This catalyst impartation method for electroless copper plating comprises bringing a material to be plated into contact with an aqueous solution containing a tin compound, into contact with the aqueous solution containing a copper compound, then into contact with the aqueous solution containing a reducing agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for applying a catalyst for electroless copper plating and a method for electroless copper plating.

[0002]

2. Description of the Related Art Conventionally, a method of forming a metal thin film on a non-conductive material such as a resin, glass, or ceramic by a wet method is performed by adsorbing a catalyst for electroless plating on a non-conductive substrate. A method of forming a metal thin film by an electroless plating method is a general method.

[0003] In such a method, palladium is widely used as a catalyst for electroless plating because of its extremely high catalytic activity, and is usually used as a sensitizer activator method, a catalyst accelerator method, or the like. According to the method described above, a catalyst application method in which a Sn / Pd mixed catalyst is adsorbed on a non-conductive substrate is adopted.

However, in recent years, metallic palladium has
The demand for catalysts for automobile exhaust gas and the like has increased, and prices have risen sharply. Therefore, demand for catalysts for electroless plating other than palladium compounds has been increasing.

[0005] Many studies and reports have been made on electroless plating catalysts that replace palladium, but many of them use expensive noble metals such as Pt, Au, Ag, and Ru. There is a demand for a method capable of forming a favorable electroless plating film using an inexpensive catalyst substance.

[0006] Further, even when stainless steel, titanium, or the like is to be plated, it is possible to perform electroless plating by adding a catalyst, but an oxide film is easily formed on these materials. Therefore, there is a disadvantage that the formed electroless plating film has poor adhesion. For this reason,
There is a demand for a pretreatment method capable of forming an electroless plating film having excellent adhesion to these materials.

[0007]

SUMMARY OF THE INVENTION The main object of the present invention is to:
An object of the present invention is to provide an electroless copper plating catalyst applying method capable of forming an electroless copper plating film having good appearance and excellent adhesion without using expensive noble metals as a catalyst metal.

[0008]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, the object to be plated was brought into contact with an aqueous solution containing a tin compound and an aqueous solution containing a copper compound sequentially. After that, by further contacting with an aqueous solution containing a reducing agent and activating it, an electroless copper plating film having a good appearance and excellent adhesion can be formed without using a noble metal compound as a catalyst substance. Have been found possible, and the present invention has been completed here.

That is, the present invention provides the following electroless copper plating catalyst application method and electroless copper plating method. 1. A method for applying a catalyst for electroless copper plating, comprising: bringing an object to be plated into contact with an aqueous solution containing a tin compound, then contacting with an aqueous solution containing a copper compound, and then contacting with an aqueous solution containing a reducing agent. 2. The aqueous solution containing a tin compound is an aqueous solution containing a water-soluble tin compound in an amount of 0.001 to 1 mol / l as a tin metal amount, and the aqueous solution containing a copper compound is an aqueous solution containing a water-soluble copper compound in an amount of copper metal, 0.001-2mol
/ L containing an aqueous solution containing at least one compound selected from amine borane, borohydride compound, hypophosphite, aldehyde and hydrazine in an amount of 0.001 to 0.5 mol. Item 1. The method for applying a catalyst for electroless copper plating according to Item 1, which is an aqueous solution containing 1 / l. 3. An electroless copper plating method, comprising: applying an electroless copper plating catalyst to an object to be plated by the method of the above item 1 or 2, and then performing an electroless copper plating treatment.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for applying a catalyst for electroless copper plating of the present invention, an object to be plated is brought into contact with an aqueous solution containing a tin compound, and then contacted with an aqueous solution containing a copper compound. The method is characterized by contacting with an aqueous solution containing an agent.

In the method of the present invention, the type of the object to be plated is not particularly limited, and a conductive material such as metal; acrylonitrile / butadiene / styrene resin (ABS resin);
Polyimide resin, epoxy resin, polycarbonate (P
C), various kinds of materials such as resins such as polyethylene terephthalate (PET), non-conductive materials such as glass and ceramics, and printed wiring boards can be used as the objects to be plated. In particular, according to the method for applying a catalyst of the present invention, it is possible to form an electroless copper plating film having good adhesion even on materials such as stainless steel and titanium in which an oxide film is easily formed.

In the method of the present invention, first, a pretreatment such as a degreasing treatment, a conditioning treatment, and an etching treatment is performed on an object to be plated, if necessary. About these processing methods, you may follow a conventional method.

Next, after the object to be plated is brought into contact with an aqueous solution containing a tin compound, it is brought into contact with an aqueous solution containing a copper compound.

In the present invention, any tin compound can be used without particular limitation as long as it is a water-soluble compound. Specific examples thereof include stannous sulfate and stannous chloride. Tin compounds can be used alone or in combination of two or more. The concentration of the tin compound in the aqueous solution containing the tin compound is 0.001 as a tin metal amount.
To about 1 mol / l, preferably 0.01 to 1 mol / l.
More preferably, it is about 0.5 mol / l.

The aqueous solution containing the tin compound can be used in a pH range in which the tin compound can be stably dissolved.
It may be about 3 or less. As the pH adjuster, for example, an inorganic acid such as sulfuric acid, hydrochloric acid, and acetic acid can be used.

The method of bringing the object to be plated into contact with the aqueous solution containing the tin compound is not particularly limited. Generally, the object to be plated may be immersed in the processing solution. Methods and the like can also be adopted.

The conditions for the treatment with the aqueous solution containing the tin compound are not particularly limited, and the solution temperature and the treatment time can be selected from a wide range, but the solution temperature of the treatment solution should be about 10 to 60 ° C. Preferably, 20 to 40 ° C
It is more preferable to set the degree. At this time, by increasing the temperature of the processing solution, it is possible to increase the amount of the tin compound adsorbed on the object to be plated. However, if the temperature of the processing solution is too high, a tetravalent tin compound is generated. This is not preferable because precipitation easily occurs. Processing time is 0.5-1
It is preferably about 0 minutes, and more preferably about 1 to 5 minutes.

The copper compound which can be added to the aqueous solution containing the copper compound may be any water-soluble compound, and specific examples thereof include copper sulfate, copper chloride, copper nitrate, and copper acetate. The copper compounds can be used alone or as a mixture of two or more.

The concentration of the copper compound in the aqueous solution containing the copper compound is 0.001 to 2 mol as the copper metal concentration.
1 / l, preferably 0.05 to 0.5 m
It is more preferably about ol / l.

The pH of the aqueous solution containing the copper compound may be within a range in which the copper compound contained in the aqueous solution can be stably dissolved, and is usually about pH 3 to 9, preferably 4 to 6.
It should be about the degree. In adjusting the pH, acetic acid, succinic acid, malonic acid,
A metal complexing agent such as maleic acid, tartaric acid or citric acid may be added.

The method of bringing the object to be plated into contact with the aqueous solution containing the copper compound is not particularly limited. Generally, the object to be plated may be immersed in the processing solution. Methods and the like can also be adopted.

The conditions for the treatment with the aqueous solution containing the copper compound are not particularly limited, and the solution temperature, the treatment time and the like can be selected from a wide range. However, the solution temperature of the treatment solution is usually about 10 to 80 ° C. Preferably 20 to 40
It is more preferable to set the temperature to about ° C. Processing time is 1 to 1
The time is preferably about 0 minutes, more preferably about 2 to 5 minutes.

Next, an activation treatment is performed by bringing the object to be plated into contact with an aqueous solution containing a reducing agent. As the reducing agent, a water-soluble compound having a reducing action can be used. Specific examples of the reducing agent include dimethylamine borane (DMAB) and trimethylamine borane (TMA).
Amine borane such as B); borohydride compounds such as potassium borohydride and sodium borohydride; hypophosphites such as sodium hypophosphite and potassium hypophosphite;
Aldehydes such as formalin; hydrazine; The reducing agents can be used alone or in combination of two or more. The concentration of the reducing agent is 0.001 to
It is preferably about 0.5 mol / l, and 0.01
More preferably, it is about 0.2 mol / l. The pH of the aqueous solution is not particularly limited, and may be appropriately set according to the type of the reducing agent to be used, within a range where the reducing performance is good and the stability of the reducing agent is not hindered. Usually, pH
It is preferred to be about 3 or more.

The method for bringing the object to be plated into contact with an aqueous solution containing a reducing agent is not particularly limited.
What is necessary is just to immerse the object to be plated in the treatment liquid, but other methods such as spraying the treatment liquid can also be adopted.

The conditions for the treatment with the aqueous solution containing the reducing agent are not particularly limited, and the temperature of the solution, the treatment time and the like can be selected from a wide range. Preferably, 50 to 70
It is more preferable to set the temperature to about ° C. Processing time is 1-2
It is preferably about 0 minutes, more preferably about 3 to 10 minutes.

After applying the catalyst by the above method, electroless copper plating is performed to form an electroless copper plating film.

As the electroless copper plating solution, various known electroless copper plating solutions can be used. Examples of such an electroless copper plating solution include copper compounds, formaldehyde as a reducing agent, glyoxylic acid, dimethylamine borane, sodium hypophosphite, etc., ethylenediaminetetraacetic acid as a complexing agent, tartaric acid, and salts thereof. Other than the above, there may be mentioned, as necessary, a self-catalytic electroless copper plating solution composed of an aqueous solution containing a pH adjuster, a stabilizer, and other additives (cyan compound, dipyridyl, thiourea, etc.). Can be. Regarding the conditions for copper plating, general plating conditions may be appropriately adopted according to the type of plating solution to be used.

Further, after forming an electroless copper plating film,
If necessary, various types of electroplating can be performed according to a conventional method.

In the method of the present invention, usually before each treatment, in order to prevent the treatment liquid from being brought in from the preceding step,
Perform a water washing process.

After applying the electroless copper plating catalyst according to the method of the present invention, the electroless copper plating is carried out to obtain a good and uniform appearance on various materials such as a non-conductive material and a conductive material. An electroless copper plating film having excellent and good adhesion can be formed. In particular, according to the method of the present invention, it is possible to form an electroless copper plating film having good adhesion even on materials such as stainless steel and titanium in which an oxide film is easily formed.

[0031]

According to the method for applying a catalyst of the present invention, excellent catalytic activity for electroless copper plating can be imparted to various objects to be plated without using an expensive noble metal compound as a catalyst substance.

The electroless copper plating film formed using the catalyst application method of the present invention is a uniform plating film having excellent adhesion.

[0033]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1 ABS resin (manufactured by Mitsubishi Rayon Co., Ltd., size 5 × 10c)
The m) and the object to be plated, this, CrO ₃ 400 g /
1 and H ₂ SO ₄ were immersed in a chromic acid etching solution containing 400 g / l at 70 ° C. for 10 minutes to perform an etching treatment.

Thereafter, 2% of 35% HCl was added to an aqueous solution containing 10 ml / l of stannous chloride as shown in Table 1 below.
After immersion at 5 ° C. for 2 minutes, it was immersed in an aqueous solution containing copper acetate at 25 ° C. for 2 minutes, and further immersed in an aqueous solution containing dimethylamine borane (DMAB) as a reducing agent at 60 ° C. for 5 minutes.

Then, it was placed in an electroless copper plating bath (OPC-build copper, manufactured by Okuno Pharmaceutical Co., Ltd.) at 50 ° C. for 10 minutes.
After immersion in electroless copper plating by immersion for minutes, the appearance and adhesion of the plating film were examined. The appearance of the plating film was visually evaluated, and the adhesion of the plating film was evaluated by attaching a cellophane tape to the plating film and determining whether or not the plating film was peeled off when the film was rapidly peeled off. The results are shown in Table 1 below.

[0037]

[Table 1] Example 2 Copper-clad through-hole board with epoxy resin on both sides (Matsushita Electric Works, Ltd.)
Made, R-1705, size 5 × 10 cm) as an object to be plated, sodium persulfate at 10 g / l and 98% sulfuric acid at 1 ml.
1 / l for 2 minutes at 25 ° C. in an etching solution containing an etching solution. Then, 98% sulfuric acid 100
It was immersed in a ml / l solution at 25 ° C for 2 minutes to remove the smut on the surface of the copper foil.

Thereafter, 35% HCl was added to an aqueous solution containing 10 ml / l of stannous chloride in an amount shown in Table 2 below.
After immersion at 5 ° C. for 2 minutes, immersion in an aqueous solution containing copper acetate at 25 ° C. for 2 minutes, and further immersion in a solution containing dimethylamine borane (DMAB) as a reducing agent at 60 ° C.
Soak for minutes.

Then, it was placed in an electroless copper plating solution (OPC-build copper, manufactured by Okuno Pharmaceutical Co., Ltd.) at 50 ° C. for 10 minutes.
After immersion in electroless copper plating by immersion for a minute, the deposition property in the through hole and the adhesion of the copper foil surface were examined.

The deposition property in the through-hole was evaluated by visually observing the deposition state of the plating film. The adhesion of the copper foil surface is as follows. After forming the electroless copper plating film, form an electrolytic copper plating film with a thickness of 30 μm, make a V-shaped cut in the surface of the electrolytic copper plating film to the epoxy resin surface, and peel off the plating film. At that time, the peeled state was visually observed and evaluated. When the plating film and the copper foil were peeled off from the epoxy resin surface while keeping the adhesion, the adhesion between the copper foil and the electroless copper plating film was good, and thus the adhesion was evaluated as good.

[0041]

[Table 2]

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4K022 AA02 AA03 AA04 AA13 BA08 CA04 CA06 CA18 CA19 DA01 DB02 DB03 DB05 DB06 5E343 AA01 AA11 BB24 BB71 CC71 DD33 ER02 ER07 GG02

Claims (3)

[Claims] 1. An electroless copper plating method comprising: bringing an object to be plated into contact with an aqueous solution containing a tin compound, then contacting with an aqueous solution containing a copper compound, and then contacting with an aqueous solution containing a reducing agent. Catalyst application method. 2. The aqueous solution containing a tin compound is prepared by converting a water-soluble tin compound to a tin metal amount of 0.001-1 mol / mol.
l containing aqueous solution, the aqueous solution containing a copper compound, the water-soluble copper compound, as a copper metal amount, 0.001 to
An aqueous solution containing 2 mol / l, and the aqueous solution containing a reducing agent contains at least one compound selected from an amine borane, a borohydride compound, a hypophosphite, an aldehyde, and hydrazine in an amount of 0.001 to 0.1. 5mol / l
The method for applying a catalyst for electroless copper plating according to claim 1, which is an aqueous solution. 3. A method for electroless copper plating, comprising applying an electroless copper plating catalyst to an object to be plated by the method according to claim 1 or 2, and then performing an electroless copper plating treatment.