JPS58759B2 - Equipment for plating processing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for plating, and particularly to an apparatus for performing plating at high speed.

The plating process performed by the apparatus of the present invention is mainly intended for printed wiring boards, and therefore the present invention will be described in connection with this.

Conventionally, various measures have been taken to shorten the time required for plating printed wiring boards.

That is, in general: (a) Either a powerful filter pump is used, a separate pump is installed, or air is injected to strongly agitate the plating solution in the plating tank. (b) Either use an oscillating cathode and oscillate the Niblint wiring board itself, which is suspended from the cathode and immersed in the plating solution. (C) Use a combination of (a) and (b) above for the required time. We are trying to shorten the time.

These conventional methods are relatively effective when the printed wiring board to be processed is small in size, but have a drawback in that sufficient effects cannot be expected when the printed wiring board is large.

That is, plating a large substrate requires a correspondingly large anode panel, which acts as a baffle plate, thus creating a uniform plating solution flow on the surface of the workpiece and ensuring a sufficient supply of metal ions. This is because the purpose of preventing adhesion of generated hydrogen gas bubbles cannot be achieved.

On the other hand, when plating long but flexible printed wiring boards, a roll-to-roll method is generally adopted, and the printed wiring board to be applied is rolled up on an unwinding roll and transferred to a long plating tank. After moving up and down in the plating solution many times through a number of rolls arranged vertically within the plating solution, it is wound up by a take-up roll.

When implementing this conventional method, if the feeding speed of the printed wiring board is increased, the resulting tensile force may cause deformation of the printed wiring board material itself, and therefore, this method rather lengthens the plating process time. The main focus is on achieving uniform plating, which is different from speeding up the plating process.

It is therefore a principal object of the present invention to provide an apparatus for plating which can completely avoid and overcome the slanting defects of prior art apparatus.

A specific object of the present invention is to provide a simple and inexpensive apparatus in which the plating solution is circulated and thus the workpiece can be plated at high speed.

These objects of the invention, as well as other aspects that will become apparent from a more thorough understanding of the invention, as well as the various advantages achieved by the invention, will be discussed in conjunction with the embodiments illustrated in the accompanying drawings. It will become clear from the detailed description below.

In the accompanying drawings, FIG. 1 illustrates one embodiment of the apparatus of the present invention for performing double-sided plating on a printed wiring board.

In the apparatus, generally designated by the reference numeral 10, 12 and 12' respectively indicate the housing halves forming a closed plating tank, the spaces within which are to be plated. It is divided into two chambers 16 and 16' by a printed wiring board 14, which is a workpiece and constitutes a cathode.

A plating solution is press-fitted into the chamber 16 from an inlet 12a provided in the housing half 12 as shown by arrow a.

The press-fitted plating solution passes through the pores 18a formed in a large number in the first dispersion plate 18, reaches the anode body 20, passes through the anode body 20, and passes through the through holes 22a formed in a large number in the second dispersion plate 22. The board 1 is brought into contact with one surface of the printed wiring board 14 through
4 is plated, and then, as indicated by the arrow, it is sucked through the pores 22b formed in the surface of the second dispersion plate 220, which faces the surface of the substrate 14 to be plated.

The waste plating solution sucked into the hole cavity 22c from the pore 22b is collected in a conventional manner, filtered, regenerated, and then returned to the inlet 12a via a pump (not shown).
It can be press-fitted into the chamber 16.

The anode body 20 illustrated in FIG.
a and metal grains 20b housed in the housing, so that the plating solution can pass through the anode body 20 while gradually dissolving the metal grains 20b.

On the other hand, a first dispersion plate 18', an anode body 20', and a second dispersion plate 22' similar to those in the chamber 16 are provided in the chamber 16', and the plating solution is forced into the chamber 16' through the introduction port 12'a. Substrate 1
The other surface of the chamber 4 is plated, but the manner in which the plating solution is circulated is exactly the same as in the chamber 16, so a description thereof will be omitted.

Incidentally, if plating is required only on one side of the printed wiring board 14, it is a matter of course that the chamber 16 or 16'
In this case, it is only necessary to press the plating solution into one of the housing halves (12 or 12') and the related elements (18, 20 and 22') housed within the housing half.
, or 18', 20', and 22') can be omitted.

Further, although both housing halves 12 and 12' have been described together as forming a closed plating tank, it is not necessary that the apparatus shown in FIG. 1 be constructed in a closed manner.

That is, FIG. 1 is a partial vertical sectional view showing one embodiment of the device of the present invention, but this will become clear if it is assumed that FIG. 1 is a cross sectional view of the device viewed from above.

In this case, the printed wiring board 14 is held between the housing halves 12 and 12', and the first and second distribution plates 18 and 18 are
', 22.degree. 22' and the anode bodies 20, 20' can be subjected to a predetermined plating process while suspended from a suitable support structure (not shown).

FIG. 2 shows a second embodiment of the present invention apparatus for plating printed wiring boards.

In the present device 100, 112 is a box constituting a plating tank, 118 and 122 are first and second dispersion plates that correspond to 18 and 22 in FIG. 1 and have the same structure,
Reference numeral 124 denotes a lid body that suppresses the spouting of the plating solution press-fitted into the chamber 116, and the anode body 120 is provided on the lid body.

The printed wiring board 114, which is the object to be plated and constitutes the cathode, is suspended by an appropriate support (not shown), and the part to be processed passes through the slit 124a formed in the lid 124. Immersed in plating solution.

The plating solution flows into the case 112 from an inlet 112a formed in the case 112 (see arrow a), passes through the first and second distribution plates 118 and 122, and flows toward the lid 124, where it is applied to the printed wiring board 114. After being subjected to the plating treatment, it is sucked and discharged from the casing 112 through the pores 122b provided in the second dispersion plate 122.

The discharged plating solution can be recycled to the inlet 112a, if necessary, in the same manner as described in connection with FIG. 1.

Figure 3 shows a long flexible printed wiring board, i.e. conventional RO
The outline of the casing of the apparatus of the present invention, which is used for plating according to the method of the present invention, is shown for printed wiring boards that have been plated using the ll-to-roll method.

The housing has one arm portion 312 and the other half portion 312', each half having an inlet 312a through which the plating solution is introduced;
312'a and connecting flange parts 312b, 312'
It has b.

Both flange portions 312b and 312'b are clamped by appropriate clamping means (not shown) to prevent the plating solution introduced into the case from leaking to the outside. The flange portions forming the feeding portion and the leaving portion of the wiring board 314 are slightly spaced apart from each other.

In the flange portions 312b, 312'b where the separation portion exists, a gutter groove 312c for accommodating the elastic strips 316, 316';
312'c is formed so that the tops of the elastic strips come into pressure contact with each other to prevent liquid leakage.

The elastic strips 316, 316' may be made of an elastic material that is stable against the plating solution, such as synthetic rubber.

In addition, the first dispersion plate 18 or 18', the anode body 20 or 20', and the second dispersion plate 22 or 22' shown in FIG. 1 are attached to each half of the housing shown in FIG. 3. be done.

The invention will now be explained in more detail with reference to examples.

Example 1 Copper plating treatment Electroless plating was applied in advance in an apparatus having a processing area of 500 x 330 mm and in which the anode body 20 and the first and second dispersion plates 18 and 22 were arranged as shown in FIG. 100
Printed wiring board with 200 through holes
×250mm) were placed.

An aqueous solution containing 200 g/l of CuSO4 and 150 g/l of H2SO4 was used as a copper plating solution, and was heated to 20 amp/dcm2.5 at room temperature using two pumps (the flow rate of each pump was 2001/min and the water head was 10 m). Copper plating treatment was carried out under the following conditions.

The thickness of the plating layer for the five sample substrates was 24 to 2.
The surface was smooth and uniform in appearance.

Example 2 Full plating process As shown in FIG. 2, a platinum anode body 120 was suspended from a polyvinyl chloride lid 124, and a phosphoric acid gold plating solution ("Oroglow 17" commercially available from Nippon Ronal Co., Ltd.) was placed in the chamber 116.
1” - containing 15 g/l as metallic gold) in a pump (40
0W, 801/min).

Thereafter, the plug terminals of the printed wiring board obtained in Example 1 were fully plated.

A plating layer thickness of 2 μm was obtained on each of the five sample substrates under plating conditions of a temperature of 40° C., 20 Amp/dcm, and 2.20 seconds.

[Brief explanation of the drawing]

In the accompanying drawings, FIG. 1 is a partial vertical sectional view showing the first embodiment of the device of the present invention, FIG. 2 is a drawing similar to FIG. 1 showing the second embodiment, and FIG. 3 is a diagram showing the device of the present invention. FIG. 2 is a schematic vertical cross-sectional view of a housing portion, and is a cross-sectional view showing a housing structure particularly suitable for processing a long flexible printed wiring board. The correspondence between the illustrated main parts of the apparatus of the present invention and reference numerals is as follows. Plating solution...No reference numeral, casing for storing plating solution...-12, 12'; 112, 124; 312
312', anode body...20; 120, plate body to be processed...14; 114; 314 (printed wiring board), plate body...22, 22'; 122 (
second dispersion plate), through hole of second dispersion plate...22a,
Suction hole cavity...22c, opening communicating with the suction hole cavity...22b; 122b.

Claims (1)

[Claims] 1. A housing containing a plating solution, an anode body disposed immersed in the plating solution inside the housing, and a workpiece disposed opposite to the anode body constituting a cathode. A plating apparatus is characterized in that a plate having a large number of through holes and an opening communicating with an internal suction hole formed on one side is disposed in close proximity to the plate to be processed. Equipment for plating processing.