JP2000199069A - Electroless nickel plating method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute good electroless nickel plating stably over a long period without causing the autolysis of an electroless nickel plating soln. in a method of executing electroless nickel plating after palladium treatment. SOLUTION: In an electroless nickel plating method in which the object to be treated is subjected to palladium treatment to adhere metallic palladium nuclei to the surface of the object to be treated, and, thereafter, the object to be treated is dipped into an electroless nickel plating soln. 2 to form an electroless nickel plating film on the surface of the object to be treated adhered with metallic palladium nuclei, a waste soln. from the electroless nickel plating soln. is used as a strike soln. 10, and the object to be treated adhered with the metallic palladium nuclei is dipped into the strike soln. and is subsequently dipped into the electroless nickel plating soln.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for electroless nickel plating of glass, ceramics, plastics and the like, particularly, a glass substrate of a hard disk, and more particularly, to a sensitizing-activating treatment of an object to be plated. The present invention relates to a method of performing electroless nickel plating after performing palladium treatment (metal palladium adhesion treatment) such as palladium treatment, and an apparatus used for the method.

[0002]

2. Description of the Related Art When electroless nickel plating is applied to a non-conductive plating object such as glass, ceramic, plastic or the like, a known palladium treatment (such as a sensitizing-activating treatment) is used. It is necessary to apply a metal palladium adhesion treatment) to attach a metal palladium nucleus to the surface of the object to be plated, and then to immerse the object in an electroless nickel plating solution.

[0003] However, when the object to be treated to which the metal palladium nuclei are adhered by performing the palladium treatment as described above is immersed in an electroless nickel plating solution, the adhered metal palladium nuclei are dropped into the plating solution. Even if the amount of the metal palladium peeled off is small, electroless nickel plating occurs using the metal palladium as a nucleus, and the plating solution eventually decomposes.
For example, the initial plating solution has a nickel ion concentration of 6 g.
/ L, the nickel ion consumption of 6 g / L is 1
When the metal palladium is dropped into the plating solution as described above, self-decomposition of the plating solution often occurs in about 0.3 turns. By the way, when such metal palladium does not peel off, the replenishment usually has a liquid life of several turns.

Therefore, a method for stabilizing an electroless nickel plating solution in a method of performing electroless nickel plating after performing the above-described palladium treatment is desired.

The present invention has been made in view of the above circumstances, and a method of performing electroless nickel plating stably for a long time in a method of performing electroless nickel plating after palladium treatment on a glass substrate of a hard disk, and the like. An object of the present invention is to provide an electroless nickel plating apparatus to be used.

[0006]

According to the present invention, in order to achieve the above object, (1) treating an object to be treated with palladium and attaching a metal palladium nucleus to the surface of the object to be treated, In the electroless nickel plating method of forming an electroless nickel plating film on the surface of the workpiece to which the metal palladium nucleus adheres by dipping in an electrolytic nickel plating solution, a drainage from the electroless nickel plating solution is used as a strike solution. Then, after the object to be treated to which the metal palladium nucleus is attached is immersed in the strike solution, the object is immersed in the electroless nickel plating solution. A palladium treatment tank containing a palladium treatment liquid for palladium treatment,
In an electroless nickel plating apparatus having an electroless nickel plating tank containing an electroless nickel plating solution,
A strike tank containing a drainage from the electroless nickel plating solution is interposed between the palladium treatment tank and the electroless nickel plating tank. Provide an electrolytic nickel plating apparatus.

According to the present invention, an object to be treated having a metal palladium nucleus adhered to its surface by palladium treatment is first immersed in a strike solution consisting of a drainage from an electroless nickel plating solution, and a certain amount of electroless nickel plating is deposited. After the occurrence of, the electroless nickel plating is performed by immersion in the electroless nickel plating solution, so that the metal palladium nucleus is hardly peeled off in the electroless nickel plating solution, so that the self-decomposition of the electroless nickel plating solution is unlikely to occur, The plating solution can be held stably for a long period of time. Therefore, the present invention is effectively applied to electroless nickel plating on a glass substrate of a hard disk.

In this case, the above-described electroless nickel plating method and apparatus are effectively employed in an automatic supply / discharge system described later.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the electroless nickel plating method of the present invention comprises a first step of palladium-treating an object to be treated and attaching a metal palladium nucleus to the surface of the object, and then a metal step. The object to be treated with the palladium nuclei adhered thereto is immersed in a strike solution consisting of a drainage of the electroless nickel plating solution to cause the second electroless nickel plating deposition.
And a third step of immersing the object in an electroless nickel plating solution.

Here, examples of the object to be processed include non-conductive materials such as glass, ceramic, and plastic.

As the palladium treatment, a known treatment method can be employed. For example, water-soluble first compounds such as stannous chloride
After immersion in an acidic aqueous solution of a tin salt (sensitizer), immersion in an acidic aqueous solution (activator) of a water-soluble palladium salt such as palladium chloride, or a sensitizing-activating treatment, or a water-soluble stannous salt and a water-soluble solution Any method of attaching a metal palladium nucleus to an object to be plated, such as a catalyzing-accelerating treatment of immersion in a catalyzer containing a neutral palladium salt and then immersion in an acid or alkali aqueous solution, can be employed.

Further, as the electroless nickel plating solution,
Any one may be used as long as it uses hypophosphite as a reducing agent, and a commercially available electroless nickel plating solution can also be used. In the present invention, the electroless nickel plating solution also includes an electroless composite nickel plating solution in which a composite material such as fluororesin particles is dispersed.
In some cases, a boron-based reducing agent such as dimethylamine borane may be used as the reducing agent.

FIG. 1 shows an electroless nickel plating apparatus according to one embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a plating tank containing an electroless nickel plating solution 2 therein. An overflow solution storage wall 3 is attached to an upper portion of the side of the plating tank 1, and a plating solution overflowing the side of the plating tank 1 is stored in the wall 3. One end of a circulation pipe 4 is connected to the bottom of the wall 3, and the other end of the circulation pipe 4 is disposed above the plating tank 1. The circulation pipe 4 is provided with a circulation pump 5 and a filter 6 in order from one end to the other end thereof, and the fine particles in the plating solution overflowing into the wall 3 and flowing into the wall 3. Is removed by the filter 6 and circulated, but when the automatic supply / discharge system is activated, a part of it is returned to the plating tank 1 from the other end of the circulation pipe 4 and the rest is discharged to the drainage column 7. The water is sent to a strike tank 9 through a guide pipe 8 connected to a drainage column 7. An overflow liquid storage wall 11 is also provided on the upper side of the strike tank 9, and the drainage (strike liquid 10) from the plating solution 2 in the strike tank 9 overflows the side of the strike tank 9. And wall 11
It is designed to flow in. The strike liquid that has flowed into the wall body 11 is discharged through the discharge pipe 12, is subjected to appropriate waste liquid treatment, and is discarded.

Here, a replenishing solution supply pipe 13 is disposed above the plating tank 1, and the replenishing solution is supplied to the plating solution from the pipe 13, whereby the increased amount of the plating solution is supplied as described above. It flows into the wall 3 by overflow. In this case, a new solution having the same composition as the plating solution can be used as the replenisher, or a concentrated solution thereof, consumption of a water-soluble nickel salt, a reducing agent, a pH adjuster (alkali such as sodium hydroxide), or the like. Although it is possible to use an aqueous solution containing the components, a part of the plating solution discharged into the wall 3 due to the overflow is circulated, and the remaining plating solution is extracted, so that the electroless nickel in the plating tank 1 is removed. In the plating solution 2, the accumulation of phosphite generated when hypophosphite is used as a reducing agent is suppressed, and the physical properties, appearance, and deposition rate of the plating film are reduced due to the accumulation of phosphite. Such disadvantages are suppressed.

Further, the extracted plating solution still has plating ability, and is used as a strike solution 1
When used as 0, good electroless plating is deposited on the plating object to which the metal palladium nuclei are attached.

Further, in FIG. 1, reference numeral 14 denotes a palladium treatment tank. Although not shown, a washing tank is provided between the palladium treatment tank 14 and the strike tank 9.

When an object to be processed is electrolessly nickel-plated using the above plating apparatus, first, a palladium treatment tank 14 is formed.
After attaching a metal palladium nucleus on the surface of the workpiece in
This is immersed in strike liquid 10 in strike tank 9,
A thin electroless nickel plating film is formed on the object to be treated, and then immersed in a plating solution 2 in a plating bath 1 to form a predetermined thickness of the electroless nickel plating film.

Therefore, according to the above method, the metal palladium nuclei adhering to the object to be processed by the palladium treatment may be peeled off to the strike solution 10, but the metal palladium nuclei are mixed in the plating solution 2 in the plating tank 1. Therefore, the plating solution is less likely to undergo self-decomposition, and good electroless nickel plating can be performed over a long period of time in combination with the partial removal of the replenisher plating solution. In this case, the strike solution is extracted for adjusting the composition of the electroless nickel plating solution, and should be discarded as it is, so that there is no waste.

[Experimental Example] Using the apparatus shown in FIG. 1, a commercially available electroless nickel plating solution (reducing agent: sodium hypophosphite, amount of Ni ions at the time of building bath 6 g / L) was used, and the amount of replenishment at one time was Ni
Replenish the respective aqueous solutions of nickel sulfate and its corresponding sodium hypophosphite and pH adjuster (sodium hydroxide) so that the ion becomes 0.1 g / L, and repeat the above replenishment 120 times to obtain a 1000 L plating solution. Updated to be updated.

Therefore, at this time, 100 per replenishment is required.
0 ÷ 120 = 8.3 L of replenisher is supplied, and the same amount of drainage is discharged. This drained liquid was used as a strike liquid. In the initial stage, 400 liters of the drainage liquid previously discharged as described above was used as the strike liquid, and in the experiment, the 8.3 liters of the drainage liquid discharged simultaneously with each replenishment was converted into a strike liquid. On the other hand, 8.3 L of liquid is naturally discharged from the strike liquid.

A glass substrate which has been subjected to a sensitizing-activating treatment as an object to be plated is placed in the above-mentioned strike solution and subjected to initial deposition of electroless nickel plating (plating conditions: 90 ° C., 1 minute). The main plating was performed with a plating solution to a film thickness of 6.5 μm (plating conditions: 90 ° C., bath ratio (processed object area / amount of plating solution): 1.5 dm).
² / L).

As a result, no self-decomposition of the electroless nickel plating solution occurred even after the replenishment was performed 1200 times.

On the other hand, when the above-described strike solution treatment was not performed, the plating solution self-decomposed after 18 replenishments.

[0024]

According to the present invention, in a method of performing electroless nickel plating after palladium treatment, stable electroless nickel plating can be stably performed over a long period without causing self-decomposition of an electroless nickel plating solution. The present invention is particularly effective for plating a glass substrate of a hard disk.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an embodiment of an electroless nickel plating apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plating tank 2 Electroless nickel plating solution 3 Overflow liquid accommodation wall 4 Circulation pipe 5 Circulation pump 6 Filter 7 Drain column 8 Induction pipe 9 Strike tank 10 Strike liquid 11 Overflow liquid accommodation wall 12 Drain pipe 13 Replenisher Supply pipe 14 Palladium treatment tank

Claims (2)

[Claims] An object to be treated is subjected to palladium treatment to attach a metal palladium nucleus to the surface of the object to be treated, and the object to be treated is immersed in an electroless nickel plating solution to adhere the metal palladium nucleus to the object to be treated. In the electroless nickel plating method of forming an electroless nickel plating film on the surface, the drainage from the electroless nickel plating solution is used as a strike solution, and the object to be treated with the metal palladium nucleus is immersed in the strike solution. And then immersing in the electroless nickel plating solution. 2. An electroless nickel plating apparatus comprising: a palladium treatment tank containing a palladium treatment liquid for palladium treating a plating solution; and an electroless nickel plating tank containing an electroless nickel plating solution. 2. The electroless nickel plating method according to claim 1, wherein a strike tank containing a drainage from the electroless nickel plating solution is interposed between the palladium treatment tank and the electroless nickel plating tank. Electroless nickel plating equipment.