JP3064712B2 - Electroless plating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroless plating apparatus used in the field of surface treatment.

[0002]

2. Description of the Related Art Conventionally, in electroless plating, various stirring operations have been performed in order to eliminate variation in the concentration distribution of the electroless plating solution in the electroless plating solution tank and to perform uniform electroless plating. . For example, Japanese Patent Application Laid-Open No. 54-123233,
Stirring by blowing gas disclosed in JP-A-59-161895 can be mentioned. Further, JP-A-63-
No. 312983 discloses a method in which a gas containing finely divided oxygen is blown into the electroless plating solution to replenish the dissolved oxygen because the concentration of dissolved oxygen in the electroless plating solution decreases as the plating reaction proceeds. ing.

However, according to the control of the dissolved oxygen concentration in the electroless plating solution in the conventional electroless plating method, the stability of the quality of the electroless plating solution cannot be said to be sufficient, and the aging of the electroless plating solution has progressed. The degree varies. Therefore, there is a need for an electroless plating method in which the deposition of a plating film on an object to be plated is stable for a long time.

The instability of the quality of the conventional electroless plating solution tends to occur in a short time when the temperature of the outside air is low. That is, when the supplied gaseous oxygen dissolves in the plating solution, the rate of dissolution of oxygen in the plating solution is reduced, and as a result, it is assumed that the deposition of the plating film on the object to be plated varies.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned drawbacks, and an object of the present invention is to provide a plating film for an object to be plated for a long time without being affected by the outside air. An object of the present invention is to provide an electroless plating apparatus that stabilizes the amount of deposition.

[0006]

According to a first aspect of the present invention, there is provided an electroless plating apparatus comprising an oxygen dissolving tank (1) for an electroless plating solution.
A supply device (12) for storing or taking in a gas containing oxygen, a detection device for detecting the temperature of the gas, and a temperature of the gas of 30 ° C. or more based on the detected signal. A controller (6) for sending an instruction signal so that the temperature is within a range from the temperature of the electroless plating solution to below the temperature of the electroless plating; a temperature controller (5) for adjusting the temperature of the gas based on the instruction signal from the controller (6); A gas diffuser (4) for diffusing gas, which has reached a predetermined temperature in the temperature controller (5), into the electroless plating solution in the oxygen dissolving tank (13) is provided.

[0007]

According to the electroless plating method of the present invention, the temperature of the gas containing oxygen to be supplied is limited to a temperature range of 30 ° C. to the temperature of the electroless plating solution, thereby dissolving oxygen in the electroless plating solution. Since the amount is stable, the plating film is stably deposited for a long time.

The gas containing oxygen is supplied by a supply device (12) for storing or taking in the gas, a detecting device for detecting the temperature of the gas, and a gas temperature of 30 ° C. based on the detected signal.
A controller (6) having a transmitter for sending an instruction signal so as to be in a temperature range of the electroless plating solution temperature, and a temperature controller (6) for adjusting the gas temperature based on the instruction signal from the controller (6). 5) A diffuser pipe (4) for diffusing the gas which has reached a predetermined temperature in the temperature controller (5) into the electroless plating solution in the electroless plating solution tank (1) and / or the oxygen dissolving tank (13). ) Is supplied to the electroless plating solution. As a result, the plating film of the object to be plated is stably deposited for a long time.

Hereinafter, the present invention will be described in detail.

An electroless plating apparatus according to the present invention will be described with reference to FIGS.

FIG. 1 is a block diagram of an electroless plating apparatus according to a reference example of the present invention, and FIG. 2 is a block diagram of an electroless plating apparatus according to the embodiment.

In the electroless plating apparatus shown in FIG. 1, an electroless plating solution tank (1) is filled with an electroless plating solution, and an object to be plated (3) is immersed in the electroless plating solution. Is applied. The electroless plating apparatus includes a supply device (12) for storing or taking in a gas containing oxygen. Examples of the supply device (12) include an oxygen cylinder when the gas is oxygen, and a blower when the gas is air. Further, a detecting device for detecting the temperature of the gas, and a temperature of the gas of 30 ° C. or more based on the detected signal.
A controller (6) for sending an instruction signal so as to be in a temperature range of the electroless plating solution temperature, and a temperature controller (5) for adjusting a gas temperature based on the instruction signal from the controller (6). As the temperature controller (5), for example, a heater may be used if only gas is heated. Further, there is provided a diffuser pipe (4) for diffusing the gas at a desired temperature into the electroless plating solution in the electroless plating solution tank (1). As the air diffuser (4), for example, in order to finely differentiate oxygen in the gas and dissolve it in the electroless plating solution, for example, a hollow porous fluororesin diffuser or a hollow porous ceramic diffuser is used. No. Providing the air diffusion tube (4) below the object to be plated (3) enhances the efficiency of dissolving oxygen in the electroless plating solution and increases the concentration distribution of the electroless plating solution in the electroless plating solution tank (1). This is preferable because the variation in is reduced. In addition, if necessary, the temperature controller (5)
A valve (7) for adjusting the supply amount of the gas whose temperature has been adjusted by (1), a flow meter (8) for measuring the supply amount of the gas passing through the valve (7), a temperature controller (5) and an electroless plating solution tank Prepare during (1).

As shown in FIG. 2, the electroless plating apparatus of the present invention is provided with an air diffusion tube (4) for diffusing the gas in an oxygen dissolution tank (13) instead of the electroless plating solution tank (1). A pump (14) for circulating the electroless plating solution between the electroless plating solution tank (1) and the oxygen dissolving tank (13), and a circulation pipe (15).

Next, the electroless plating method will be described with reference to FIG.

The electroless plating solution tank (1) is filled with an electroless plating solution for plating. As this electroless plating solution, various known electroless plating solutions are used,
Examples include electroless copper plating and electroless nickel plating. The temperature of the plating solution is generally maintained at 50 ° C to 90 ° C.

In the above, a gas containing oxygen is stored or taken in using a supply device (12) such as an oxygen cylinder or a blower. The temperature of the gas is detected by a detection device provided in the controller (6), and based on the detected signal, the temperature of the gas is adjusted to a temperature range of 30 ° C. to the temperature of the electroless plating solution. Send an instruction signal to 5). The temperature of the gas is adjusted to a predetermined temperature by the temperature controller (5) based on the instruction signal from the controller (6). Also,
If necessary, the temperature of the gas is adjusted, and the opening / closing degree of the valve (7) is adjusted so that the gas supply amount is kept constant by the flow meter (8).

Then, the gas having reached a desired temperature is
The gas is diffused into the electroless plating solution from a diffuser tube (4) provided in the electroless plating solution tank (1). Since the gas containing oxygen to be diffused is in the temperature range of 30 ° C. to the temperature of the electroless plating solution, the temperature of the electroless plating solution does not decrease. Therefore, the dissolution rate of oxygen in the electroless plating solution is reduced. And stabilizes the deposition amount of the plating film over a long period of time.

According to the electroless plating method of the present invention, as shown in FIG. 2, an air diffusion tube (4) is provided in an oxygen dissolution tank (13) instead of the electroless plating solution tank (1). (1
A gas containing oxygen in the temperature range of 30 ° C. to the electroless plating solution temperature is diffused into the plating solution in 3), and the oxygen dissolving tank (1) is diffused.
There is a method of circulating the electroless plating solution in 3) and the electroless plating solution in the electroless plating solution tank (1). When the oxygen dissolving tank (13) is provided, the electroless plating solution adjusted to a desired dissolved oxygen concentration in the oxygen dissolving tank (13) is sent to the electroless plating solution tank (1), so that the gas is directly transferred to the plating object. This is useful when you do not want to apply (3).

In the present invention, the electroless plating solution in the electroless plating solution tank (1) measures the concentration of a metal ion, the concentration of a reducing agent, the pH value, etc., and changes the electroless plating solution with the plating reaction. In order to maintain the composition of the solution, a metal ion compound, a reducing agent for the metal ion, and a pH adjuster are newly supplied to the electroless plating solution as appropriate.

[0020]

EXAMPLES Reference Example 1 Electroless copper plating was performed using the electroless plating apparatus shown in FIG. The electroless plating solution tank (1) was filled with the following electroless copper plating solution. In addition, sodium hydroxide was added to this electroless copper plating solution as a pH adjuster, and the pH was measured to be 12.0. A copper plate was immersed in the electroless copper plating solution as a plating object (3). The copper ion concentration, formalin concentration, and pH value of the electroless copper plating solution in the electroless plating solution tank (1) are measured, and the copper ion, formalin, and hydroxide are adjusted so that the above-mentioned concentration and pH become constant with the plating reaction. Supplemented with sodium.

Conditions for the electroless copper plating solution: Copper sulfate --------------- 10 g / liter EDTA--30 g / liter -Formalin --------- 5g / liter ・ Cyanide additive --10mg / liter ・ Polyethylene glycol -200mg / liter ・ pH --------------- 12.0 ・ Liquid temperature ---- −−−−− 60 ° C. As the gas containing oxygen, oxygen from an oxygen cylinder as the supply device (12) was used. The temperature of the oxygen is controlled by the controller (6).
Oxygen was heated by a temperature controller (5) to 40 ± 5 ° C. based on a signal detected by a detection device provided therein.
A diffuser tube (4) made of porous fluororesin is provided at the bottom of the electroless plating solution tank (1), and the oxygen is supplied to the electroless plating solution tank (1).
The inside of the electroless plating solution was diffused. The dissolved oxygen concentration of the electroless plating solution during the plating process could be maintained at a constant value of 1 ppm.

As a result, the electroless copper plating was performed up to 15 turns indicating the aging degree of the plating. However, no copper was deposited in the electroless plating solution tank (1), and during this time, the plating object (3)
The deposition of the plating film on the surface was good.

REFERENCE EXAMPLE 2 The same electroless copper plating as in Reference Example 1 except that the gas containing oxygen of Reference Example 1 was introduced by a blower as a supply unit (12) using air instead of oxygen in an oxygen cylinder. The test was carried out under the conditions of gas temperature.

As a result, the electroless copper plating was performed up to 15 turns indicating the aging degree of the plating. However, no copper was deposited in the electroless plating solution tank (1).
The deposition of the plating film on the surface was good.

Reference Example 3 Electroless nickel plating was performed using the same electroless plating apparatus as in Reference Example 1. The electroless plating solution tank (1) is filled with the following electroless nickel plating solution, and the object to be plated (3)
The copper plate was subjected to electroless nickel plating. The nickel ion concentration, sodium hypophosphite concentration, and pH value of the electroless nickel plating solution in the electroless plating solution tank (1) were measured, and nickel ions were added so that the concentration and pH became constant with the plating reaction. Supplemented with sodium hypophosphite, sodium hydroxide or sulfuric acid.

Conditions for electroless nickel plating solution Nickel sulfate hexahydrate 30 g / liter Sodium hypophosphite 30 g / liter Glycine 20 g / l sodium citrate 20 g / l lead-based additive 10 mg / l pH- −−−−−−−−−−−−−− 5.5 liquid temperature −−−−−−−−−−−−− 90 ° C. The gas containing oxygen uses air, and the feeder (12) Was taken in by a blower. The temperature of the air was heated by a temperature controller (5) to 60 ± 5 ° C. based on a signal detected by a detection device provided in the controller (6). A diffuser tube (4) made of porous fluororesin was provided at the bottom of the electroless plating solution tank (1), and the air was diffused into the electroless nickel plating solution in the electroless plating solution tank (1). The dissolved oxygen concentration of the electroless nickel plating solution during the plating process is 0.1.
It could be kept at a constant value of 5 ppm.

As a result, electroless nickel plating was performed up to 12 turns indicating the aging degree of the plating. However, no nickel was deposited in the electroless plating solution tank (1). The deposition of the plating film was good.

Example 1 Electroless copper plating was performed using an electroless plating apparatus shown in FIG. Conditions for electroless copper plating, plating object (3)
Was the same as in Reference Example 1.

The gas containing oxygen uses air, and the feeder (1
2) was taken in by the blower. The temperature of the air was heated by the temperature controller (5) to 40 ± 5 ° C. based on a signal detected by a detection device provided in the controller (6).

An air diffusion tube (4) made of porous fluororesin is provided at the bottom of the oxygen dissolution tank (13), and the air is supplied to the oxygen dissolution tank (1).
Air was diffused from the diffuser tube (4) to the electroless plating solution in 3).
The pump (14) provided in the pipe (15) is operated, and the electroless plating solution in the oxygen dissolving tank (13) is sent to the electroless plating solution tank (1), and the electroless plating liquid is electrolessly supplied to another pipe (16). The electroless plating solution in the plating solution tank (1) was returned to the oxygen dissolving tank (13), and the electroless plating solution in the oxygen dissolving tank (13) and the electroless plating solution tank (1) was circulated. The concentration of dissolved oxygen in the electroless copper plating solution in the electroless plating solution tank (1) during plating is 1
ppm could be maintained at a constant value.

As a result, the electroless copper plating was performed up to 15 turns indicating the aging degree of the plating. However, no copper was deposited in the electroless plating solution tank (1).
The deposition of the plating film on the surface was good.

Comparative Example 1 Electroless copper plating was performed in the same manner as in Reference Example 2 except that the temperature of the air in Reference Example 2 was changed to 20 ± 5 ° C. The dissolved oxygen concentration of the electroless copper plating solution in the electroless plating solution tank (1) during the plating process was 0.3 ppm, which was lower than that of the example.

As a result, copper deposition occurred in the electroless plating solution tank (1) in 11 turns indicating the aging degree of plating.

[0034]

According to the electroless plating apparatus of the present invention,
It is possible to improve the deposition of a plating film on an object to be plated for a long time without being affected by the outside air.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electroless plating apparatus according to a reference example of the present invention.

FIG. 2 is a block diagram of an electroless plating apparatus according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electroless plating solution tank 3 Plated object 4 Air diffuser 5 Temperature controller 6 Controller 7 Valve 8 Flow meter 12 Feeder 13 Oxygen dissolving tank 14 Pump 15 Piping

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yasushi Yoshii 1048 Odakadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd. (56) References JP 4-157170 (JP, A) JP 63-69999 ( JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C23C 18/00-18/54

Claims (1)

(57) [Claims] An electroless plating apparatus having an oxygen dissolving tank (13) for an electroless plating solution, a supply device (12) for storing or taking in a gas containing oxygen, a detection device for detecting the temperature of the gas, A controller (6) that sends an instruction signal based on the detected signal so that the temperature of the gas is in a temperature range from 30 ° C. or more to a liquid temperature of electroless plating, and based on the instruction signal from the controller (6). Temperature controller (5) for adjusting the temperature of gas, this temperature controller (5)
The electroless plating apparatus according to claim 1, further comprising a diffuser pipe (4) for diffusing gas having a predetermined temperature into the electroless plating solution in the oxygen dissolving tank (13).