JPS5841346B2 - Metsuki method - Google Patents

Description

[Detailed description of the invention] This invention relates to a novel plating method.

Generally known plating methods include electroplating and chemical plating.

In the case of electroplating, the plating speed is very fast, so it is widely used industrially.

However, electroplating cannot directly plate an insulating material such as plastic, and it is necessary to apply a thin chemical plating before electroplating.

In addition, when electroplating something with many floating islands, such as a printed circuit, it is necessary to provide an electrode on each floating island, which makes the work extremely troublesome.

On the other hand, chemical plating does not require an electric field at all, so even printed circuits with many floating islands can be easily and uniformly plated.

However, the plating speed of chemical plating is extremely slow compared to electroplating, and most commercially available plating solutions are 1 μm to 3.5 μm per hour.

Therefore, when a thickness of 20 to 30 .mu.m is required, there is a drawback that the open plated object must be immersed in the plating solution for several hours to 30 hours.

This invention aims to provide a plating method that eliminates the disadvantage of slow plating speed even though it is a chemical plating method in principle.The present invention is characterized by the fact that a pair of electrodes are placed in the chemical plating solution together with the object to be plated. The purpose of this method is to provide a plating device and pass a current between both electrodes to perform plating.

For example, as shown in the figure, a pair of electrodes 21 and 22 are provided in the chemical plating solution 1, and the objects to be plated 3a, 3b, . The electrodes are placed at intervals that allow for sufficient circulation, and plating is performed while passing current from the power source 4 between the electrodes 21 and 2□.

In this case, the current is 0.000 rf/Ll of chemical plating solution.
It may be adjusted as appropriate within the range of 05 to 10A.

The desirable current value is 0.2 to 3 per 500 TL of plating solution.
Although it is about A, it is more desirable to find the optimum value depending on the type of chemical plating solution.

This is because if a large current is applied to a solution with a high plating speed, the solution may decompose in a short period of time.

. The current may be either alternating current or direct current, and the plating speed changes depending on the current value or electric field strength, but as will be clear from the examples described later, the approximate value is AC IA1.
The speed increases by about 3 to 3.5 times with 5 ooml.

Of course, it differs somewhat depending on the type of plating solution.

Furthermore, the way the plating is done is different depending on whether the current is alternating current or direct current.

First, in the case of alternating current, a plating layer is uniformly formed on both sides of the object to be plated.

On the other hand, in the case of direct current, the surface facing the positive electrode is heavily plated, and the surface facing the negative electrode is plated very little or not at all.

For example, when the object to be plated is a metal such as stainless steel or nickel that is difficult to plate with a copper plating solution, the surface facing the negative electrode was not plated at all even when direct current was applied.

At present, it is not clear why the plating speed is increased by passing a current through the plating solution, but there is no doubt that the chemical plating solution is considerably activated by the current or electric field.

For example, if you try to plate a stainless steel plate without an electric field using Hitachi Chemical's -5 chemical copper plating solution, it will not plate at all, but this can be proven by the fact that it was plated by passing an AC or DC current of about LA1500TLl.

The electrode material is not particularly limited, but it is desirable that it be a material that does not have an adverse effect on the chemical plating solution and is resistant to plating.

Hereinafter, the effects of this invention will be clarified through Examples.

Example 1 A chemical copper plating solution manufactured by Hitachi Chemical with -5 prepared in a standard composition was prepared in 500 columns, adjusted in a water bath so that the plating solution reached 50°C, and stirred with a magnetic cooler. Plating was carried out for 15 minutes while applying a current of 0.2 AC according to the method shown in the figure.

As the object to be plated, a nickel plate measuring 6 mm x 4 mm x 0.05 mm was used, and as an electrode, a stainless steel plate with a thickness of 0.8 mm was used.

As a result, uniform copper plating was achieved on both sides of the nickel plate.

The plating layer had a thickness of 0.77 cm/111 cm on one side.

Example 2 The same process as in Example 1 was performed except that the traffic current was set to 0.5A.

As a result, both sides were uniformly plated with copper, and the plating layer was 1.1 square centimeters per 1 d of each side.

Example 3 The same process as in Example 1 was performed except that the alternating current was changed to IA.

As a result, uniform copper plating was achieved on both sides, with a plating layer thickness of 1.681119 per 1 d of one side.

Example 4 The same process as in Example 1 was performed except that the alternating current was 1.5A.

As a result, both sides are uniformly plated with copper, and the plating layer is IC1 on one side. It was 2.271n9 per L.

Example 5 The same process as in Example 3 was performed except that the number of objects to be plated as described in Example 1 was changed to three.

As a result, all three sheets were uniformly plated with copper on both sides, and the plating layer was 165 to 1.7 rfu per side. Met.

Example 6 The same process as in Example 1 was performed except that the DC current was 0.5 A.

As a result, only the surface facing the positive electrode was plated, and the plating layer was 1.05 m9 per 1.

Example 7 The same process as in Example 1 was performed except that the DC current IA was used.

As a result, as in Example 6, only the surface facing the positive electrode was plated, but the plating layer was 1.35 mg per 1 d.

Example 8 The same process as in Example 1 was performed except that the chemical plating solution was kept at room temperature (approximately 20° C.).

As a result, almost no plating was achieved.

However, when the alternating current was changed to IA, uniform plating was achieved on both sides.

The plating layer had a thickness of about 0.791 r19 per 1 on one side.

Comparative Example The same process as in Example 1 was carried out except that there was no electric field.

Both sides were plated, but the plating layer was 1 cf on one side? The plating rate was 0.57r19 per L, which demonstrated that the plating rate was considerably slower than in Example 1.

[Brief explanation of the drawing]

The figure is for explaining the plating method according to the present invention. 1... Chemical plating solution, 21, 22...
Electrodes, 8a to 3e...Things to be plated, 4...
··power supply.

Claims (1)

[Claims] 1. A plating method characterized by providing a pair of electrodes together with the object to be plated in a chemical plating solution, and plating by passing an electric current between the two electrodes.