JPS5938758B2 - Masking plate for partial plating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a masking plate for partial plating for performing partial plating on a circuit board or the like on which a conductive pattern is formed on an insulating substrate, and the masking plate is used together with a partial plating device. Ru.

The conventional method of mounting an IC or LSI using a circuit board is to form the IC or LSI from a metal plate such as Kovar, and mount it on a gold-plated lead frame.
Previously, bonding was used to attach this to a circuit board, but recently, IC or LSI
It has become common to attach and bond directly to the circuit board. Ta. For this reason, in order to bond bonding wires led out from each electrode of an IC or LSI, as was done for lead frames, a bondable metal such as gold is used as a conductor of a circuit board.

It became necessary to apply approximately 1 to 5 microns to the body pattern. Further, it is strongly desired from an economical point of view to save expensive money that this plated portion be provided only in the area where bonding is to be performed, as is done on the lead frame. However, unlike lead frames, which are made entirely of metal, circuit boards
A conductor pattern is formed on an insulating substrate.

For this reason, the method used for lead frames, i.e.
In an apparatus that performs partial plating by spraying a plating solution from a plating solution injection nozzle serving as an anode and placing an object to be plated through a masking plate for partial plating, the masking plate is used for partial plating as shown in FIG. This method is used for partial plating of circuit boards by using an insulating rubber with a window and a thin metal plate placed inside the insulating rubber, and taking the cathode lead from one end of the lead frame. It was difficult to do so for the following reasons. To use this method, it is necessary to remove plated leads from all of the conductor patterns on the circuit board, and the work of attaching and removing such plated leads becomes difficult as the number of conductor patterns increases, and it becomes difficult in the manufacturing process. too,
There were also problems from an economic perspective. Another conventional method is to form a pattern by shortening each conductor pattern, then apply a plating resist except for the partially plated parts, and then apply gold plating to form the pattern. , after removing the plating resist,
Another method is to remove the shortened portion of each conductor pattern. However, even with this method, there are labor-intensive operations such as applying plating resist, peeling, and removing the shoting part, and there are
There were major economic disadvantages. The present invention eliminates the conventional drawbacks, simplifies partial plating on circuit boards, etc., and
It is an object of the present invention to provide a masking plate for partial plating of a partial plating apparatus that can be suitable for mass production.

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

First, as shown in Fig. 1, the partial plating device used in the example includes a pressure box 1 for uniformly spraying the plating liquid from each nozzle, and a plating liquid as an anode attached to the pressure box. injection nozzle 2,
It is composed of a support 3 for attaching and positioning an object to be plated such as a circuit board, a cover 6, a plating liquid layer, a plating liquid pressure pump, etc.

During plating, a masking plate 4 is manufactured on the support 3 so that the plating liquid hits only the desired portions, and an object to be plated such as a circuit board 5 is mounted on the masking plate 4, and plating is performed. It's becoming like that. The material of the pressure box, object support, and cover is plastic or F, which can withstand the temperature of the plating solution.
RP is mainly used.

The material of the plating liquid injection nozzle as an anode is titanium.
This is plated with platinum or rhodium. As shown in FIG. 3, the structure of the masking plate for partial plating of the present invention, which is used in the partial plating apparatus to perform partial plating, is as shown in FIG. It consists of a thin metal plate 11 and an insulating frame 10 formed around the inner periphery of the window for partial plating.

The thin metal plate used for the masking plate is made of stainless steel or the like, and this reinforces the conductive rubber, which is easily expanded and contracted by heat, and improves dimensional stability.

Furthermore, when removing the cathode for plating, in this plating device, it is removed from the masking plate, but if it is removed directly from the conductive rubber, the resistance of the conductive rubber is large, so
Since there are various problems such as variations in plating thickness depending on the nozzle position, this thin metal plate also serves as a terminal for taking the cathode lead. The conductive rubber and the insulating frame are preferably made of materials that can withstand heat, plating liquid, etc., such as silicone rubber.

The method for manufacturing this masking plate is as follows: A thin metal plate is set as the middle layer in a mold made so that the desired partially plated portion becomes a window, and a conductive rubber material is poured into this and molded. Next, it is removed from the mold, placed in a molding circle to form an insulating frame around the inner periphery of the partially plated window, and the insulating frame material is added and molded to complete the masking plate.

In addition, forming the insulating frame on the inner periphery of the partially plated window is as follows:
This is due to the following reasons.

When plating is performed using a masking plate consisting only of conductive rubber and a thin metal plate placed inside the masking plate, plating is deposited on the inner periphery of the window at the partially plated part, and after plating, the plating on this part is removed from the masking plate. It peels off from the board, remains on the conductor patterns of the circuit board, and bridges between the conductor patterns, causing a serious problem in terms of the functionality of the circuit board. As a result of various studies to prevent this bridging phenomenon, it was found that this phenomenon could be prevented by forming an insulating frame around the inner periphery of the window in the partially-plated area, and that there was no problem with partially-plated. It is something that was given. Here, a method of partial plating using the masking plate of the present invention will be described below. First, the circuit board 5 is set on the substrate 3 to be plated via the masking plate 4, the cover 6 is attached to the top of the circuit board 5, and pressure is applied to bring the masking plate 4 and the circuit board 5 into close contact with each other. The plating liquid is sprayed from the injection nozzle 2 of the metal thin plate 1 of the masking plate 4 to the cathode lead.
1, and by passing a direct current through the conductor pattern through the thin metal plate 11 and the conductive rubber 9, partial plating can be performed.

Incidentally, the partial plating using the masking plate of the present invention is not limited to gold plating, and can be any type of plating such as silver plating or nickel plating.

Further, the partial plating device is not limited to the one used in this embodiment, but any device that can use the masking plate of the present invention may be used.

As described above, according to the present invention, it is possible to easily and mass-produce partial plating of circuit boards, etc., on which conductive patterns are formed on insulating substrate soil, and the plating can also be performed on lead frames. It is as good as the partial plating of .

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing a partial plating device used in an embodiment of the present invention, FIG. 2 a is a plan view of a masking plate used for partial plating of a lead frame, and FIG.
3A is a plan view showing one embodiment of the masking plate of the present invention, and FIG. 3B is a sectional view of FIG. 1. ．． ．． ．． ．． ．． Pressure Box, 2...
Plating liquid injection nozzle, 3... object support, 4... masking plate, 5... object to be plated, 6... cover.

Claims (1)

[Claims] 1. A masking plate for partial plating consisting of a conductive rubber having a window for partial plating, a thin metal plate placed inside the conductive rubber, and an insulating frame formed around the inner periphery of the window for partial plating.