JPH05148694A - Electroplating device for printed wiring board - Google Patents

Abstract

PURPOSE:To easily form a plating layer uniform in thickness on the principal plane of a printed wiring board, etc. CONSTITUTION:This device is provided with a plating tank 1, an anode 5 arranged in the tank 1, a support 4 (plating jig) for dipping a printed wiring board 2 opposed to the anode 5 in a plating soln. in the tank 1, a shielding unit 9 having plural openings 8 on the side confronted with the board 2 and surrounding the anode 5, means 10 and 12 for reciprocating the unit 9 almost in parallel with the board 2 and an electric circuit 14 for supplying a requiste plating current to the board 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board electroplating apparatus, and more particularly to a wiring board electroplating apparatus suitable for performing panel copper plating or patterned copper plating on a main surface of a board.

[0002]

2. Description of the Related Art For example, in a manufacturing process of a printed wiring board (wiring board), an electroplating method is known as one means for forming a required conductor layer or circuit pattern on a main surface of an insulating substrate. That is, an insulating substrate such as a pheno
Apply a copper electroplating layer on the surface of a laminated board made of resin-based resin or the like, on a thin copper foil layer or chemical plating layer that has been laminated in advance, or on a circuit pattern including the inner wall surface of the through hole. Means for constructing thick conductor layers or circuit patterns are known.

In order to carry out such an electroplating process, an electroplating apparatus whose schematic structure is shown in cross section in FIG. 4 is used. That is, an electroplating apparatus including an electroplating bath main body 1 and a plating jig 4 that supports a substrate 2 to be plated and is immersed in a plating solution 3 contained in the plating bath main body 1 is used. The plating jig 4 is connected to a power source via a rectifier and causes the substrate to be plated 2 that supports it to function as a cathode. Further, in FIG. 4, reference numeral 5 denotes an anode (anode) connected to the positive power source, which is housed in a net-shaped anode case 6 and arranged in the plating tank body 1.

The electroplating of the wiring board by the electroplating apparatus thus constructed is performed as follows. That is, the plating jig 4 corresponding to each substrate 2 to be plated having the same size, circuit pattern area or density.
Is prepared, and the plating current is adjusted to control the amount of movement of metal cations to the cathode (the substrate 2 to be plated), whereby the required plating layer is deposited. Further, in order to prevent the electric current, that is, metal cations, from flowing from the surroundings to the plated substrate 2, the anode 5
Plating tank body 1 between the cathode and the cathode (substrate to be plated 2)
Shielding plates 7 are fixedly arranged on the bottom and sides.

[0005]

However, the above electroplating apparatus has the following problems. That is, the arrangement of the shielding plate 7 can prevent the metal cations from wrapping around from the bottom and sides of the plating tank main body 1, but FIG. 5 schematically shows the distribution state by taking the case of copper plating as an example. As described above, the distance between the anode 5 and the cathode (the substrate 2 to be plated) is different in each part of the substrate 2 to be plated, so that there are places where copper ions are concentrated. Therefore, there is a problem in that the thickness of the deposited plating layer varies by about ± 5 μm and a highly reliable wiring board cannot be obtained.

The present invention has been made to solve the above problems, and a plating layer having a uniform thickness can be easily formed on the surface of a substrate by controlling the direction of the current generated by the movement of metal cations. An object of the present invention is to provide an electroplating device for a wiring board that can be formed by deposition.

[0007]

An electroplating apparatus for wiring boards according to the present invention includes a plating tank body, an anode disposed in the plating tank body, and a substrate to be plated facing the anode. A support body that is immersed and supported in a plating solution in the bath main body, and a shield that has a plurality of openings on the side facing the substrate to be plated that is immersed and supported by the support body, and that is surrounded by the anode. It is characterized by comprising a unit, a movable means for reciprocating the shielding unit substantially parallel to the substrate to be plated, and an electric circuit for supplying a required plating current to the substrate to be plated.

[0008]

According to the electroplating apparatus for wiring boards of the present invention, the shielding unit is arranged around the anode so as to surround the anode, and a plurality of shielding units are provided on the side facing the substrate to be plated. Of the metal cations emitted from the anode, only the ions that have passed through the opening of the shielding unit reach the substrate to be plated, which is the cathode. That is, the emission direction of the metal cations, in other words, the direction in which the plating current flows is limited to the position direction of the opening of the shielding unit. And
Since such a shielding unit is reciprocated by the movable means in a direction parallel to the substrate to be plated, and the position of the open portion also moves in the same direction, the direction of the plating current changes periodically accordingly. As a result, a plating layer having a uniform thickness is deposited on the main surface of the substrate to be plated.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 and FIG. 2 respectively show an example of the essential configuration of an electroplating apparatus for wiring boards according to the present invention. FIG. 1 is a front view and FIG. 2 is a top view. In FIG. 1, the substrate to be plated and the plating jig that supports it are omitted for clarity.

In these figures, 1 is an electroplating bath main body, 2 is a substrate to be plated, 3 is a plating solution contained in the electroplating bath body 1, and 4 is a substrate to be plated 2 which will be described later. A plating jig (support) that is immersed in the plating solution 3 so as to face the anode is shown. Reference numeral 5 denotes an anode such as a copper ball, which is housed in a net-shaped anode case 6 and arranged in the plating tank body 1. Furthermore, the entire anode 5 is the plating support (jig) 4
A box-shaped shielding unit 9 provided with a plurality of vertical slit-shaped openings 8 at regular intervals on the surface facing the substrate 2 to be plated, which is supported by the substrate and immersed in the electroplating bath main body 1. It is surrounded by. The upper flange portion of the shielding unit 9 is locked to a rail 10 horizontally arranged on the upper end portion of the plating tank body 1 via a roller 11, and an air cylinder 12 is connected to one end of the rail 10. ing. Here, the operation of the air cylinder 12 is controlled by the air switching valve 13. That is, the shielding unit 9 is configured to be reciprocally movable in the left and right directions along the rail 10 by the air cylinder 12.

Further, 15 is an electric circuit for supplying a required plating current to the substrate 2 to be plated through the cathode power feeding portion, while supplying a required plating current to the anode 5 through the anode power feeding portion, and 15 is a shield. A circulation means for causing the plating solution 3 to flow in a certain direction in the unit 9 or the like,
A plating solution injection pipe 16, a plating solution suction pipe 17 and a circulation pump 18 are provided.

Next, an operation or an example of use of the electroplating apparatus for a wiring board having the above structure will be described. First, the required substrate 2 to be plated is mounted on the plating support (jig) 4 and immersed in the plating solution 3 contained in the electroplating bath main body 1. Then, in this state, the circulation pump 18 is operated to circulate the plating solution 3 in the electroplating bath main body 1, while the air cylinder 12 is operated to move the shielding unit 9 along the rail 10. At this time, if it moves to the left or right direction to the required limit, the air switching valve 1
The operation direction of the air cylinder 12 is switched to the opposite direction by switching 3 and the operation is appropriately repeated, so that the shielding unit 9 is continuously reciprocated. In this way, while circulating the plating solution 3 and moving the shielding unit 9, the electric circuit 14 that supplies the plating current is driven to proceed with the required electroplating process.

In such a plating process, as shown schematically in FIGS. 3 (a) and 3 (b) by taking the case of copper plating as an example, among the copper ions released from the anode 5, Only the material passing through the opening 8 of the shield unit 9 reaches the substrate 2 to be plated, which is the cathode, so that the plating current flows only in the position direction of the opening 8 of the shield unit 9. Further, the shielding unit 9 having such an open portion 8 is reciprocated by the air cylinder 12 in a direction substantially parallel to the main surface of the substrate 2 to be plated. The movement of the plating current periodically changes the direction of the plating current. Therefore, on the main surface of the substrate 2 to be plated, the anode 5
A plating layer having a uniform thickness and having a uniform thickness as a whole is deposited without being affected by the position and distance between the two. Specifically, it is possible to reduce the thickness variation of the plating layer to ± 2 μm.

In the above configuration example, the air cylinder 12 is used as the air switching valve 1 as means for reciprocating the shielding unit 9 in a direction substantially parallel to the main surface of the substrate 2 to be plated.
Although it was switched by 3 and reciprocated along the rail 10, the means of continuous reciprocation of the shielding unit 9 (movement of the opening 8) is not limited to the means exemplified above.

[0016]

As is clear from the above description, according to the electroplating apparatus for wiring boards of the present invention, the direction of the plating current generated by the movement of the metal cations from the anode to the cathode is not biased in one direction. Therefore, a uniform plating layer having a desired thickness can be easily deposited on the main surface of the wiring board.

[Brief description of drawings]

FIG. 1 is a front view showing a configuration example of a main part of an electroplating apparatus for a wiring board according to the present invention.

FIG. 2 is a top view showing a configuration example of a main part of an electroplating apparatus for a wiring board according to the present invention.

FIG. 3 schematically shows a distribution of plating current in the electroplating apparatus for a wiring board according to the present invention, where a is a plan view showing a current distribution state when the shielding unit is at a position, and b is a shield. The top view which shows a current distribution when a unit moves an open part from the position of the said a.

FIG. 4 is a front view showing a configuration of a main part of a conventional electroplating apparatus for wiring boards.

FIG. 5 is a plan view schematically showing a distribution state of a plating current in a conventional electroplating apparatus for wiring boards.

[Explanation of symbols]

1 ... Electroplating bath main body 2 ... Plated substrate 3 ... Plating solution 4 ... Plated substrate support (plating jig) 5
... Anode 6 ... Anode case 7 ... Shield plate
8 ... Opening part 9 ... Shielding unit 10 ... Rail
11 ... Roller 12 ... Air cylinder 13 ... Air switching valve 14 ... Plating current supply electric circuit 15 ... Plating solution circulation means 16 ... Plating solution injection pipe 17 ... Plating solution suction pipe 18 ... Circulation pump

Claims (1)

[Claims] 1. A plating bath main body, an anode (anode) disposed in the plating bath main body, and a support for supporting the substrate to be plated by dipping and supporting the substrate to be plated in a plating liquid in the plating bath main body. A shield unit having a plurality of open portions on the side facing the substrate to be plated, which is supported by immersion in a plating solution by the support, and arranged around the anode, and the shielding unit with respect to the substrate to be plated. And an electric circuit for supplying a required plating current to the substrate to be plated, and an electroplating apparatus for a wiring substrate.