JPH0138395B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for performing primary copper plating in a printed circuit board manufacturing process.

Generally, the printed circuit board manufacturing process involves a primary copper plating process in which copper plating is applied to the entire surface of the board material such as a phenol board, and a pattern plate is created by masking the primary copper plating and using electrolytic copper plating (secondary copper) and solder plating. The process is roughly divided into the process of etching the pattern plate and the process of etching the pattern plate. The primary copper plating process is divided into pretreatment, chemical plating (copper), and electroplating (copper), and conventionally, primary copper plating has been performed by one of the following two methods. In other words, one method uses basket 1 in Figure 1 and rack 2 in Figure 2. First, a large number of vertical printed circuit boards P (materials) are stacked horizontally in the basket 1 with a gap m between them. In this state, it is immersed in a chemical plating tank (not shown). When the chemical plating is completed and the car 1 is lifted out of the plating tank, the substrate P is removed from the car 1 and attached to the rack 2. The rack 2 has a vertical frame shape and is designed to hold several substrates P in the same vertical plane within the rack 2.
is held in the rack 2 and immersed in an electroplating bath (not shown). However, according to this method, there are problems in that it takes time and effort to transfer the substrate P from the basket 1 to the rack 2, and the substrate P is easily soiled during the operation. Furthermore, the equipment is divided into two, for example, transport and recovery equipment for car 1 and rack 2.
Since it is necessary to provide separate transportation and recovery equipment, there is a problem that equipment costs and occupied space increase.

In contrast to this conventional method, the other conventional method performs both chemical plating and electroplating while holding the substrate P in rack 2. According to this one rack method, the problems that occur when using cage 1 are avoided. Solvable. However, the one-rack method has the disadvantage of poor productivity because only a small number of substrates P can be processed at a time. Another drawback is that chemical plating has a poor load factor. In other words, chemical plating has the characteristic that the chemical reaction will not proceed properly unless the processing area (more than a certain number of substrates) exceeds a certain value for the amount of liquid, whereas in the one-lucky method, substrates are immersed in the chemical plating liquid at the same time. Since the number of substrates to be processed is small, there is a problem that the processing area is insufficient for the amount of liquid and the processing conditions are deteriorated.

In order to solve the above-mentioned conventional problems, the present invention has the following features:
A plurality of printed circuit boards are housed in a basket in an inclined position at intervals vertically, and while housed in the basket, the printed circuit boards are sequentially immersed in both a chemical plating bath and an electroplating bath. is inserted into the above-mentioned gap between printed circuit boards after chemical plating treatment, and will be explained with reference to the drawings as follows.

In FIG. 3, which is a schematic perspective view, the apparatus according to the invention includes a chemical plating bath 5 and an electroplating bath 6 for primary copper plating, and a large number of printed circuit boards (for example, 12 or more; only five are shown in FIG. 3). It is equipped with a cage 7 for accommodating P, and an anode 8 (positive electrode) for electroplating. Both plating tanks 5 and 6 are provided in the middle of the processing tank group 9, and before and after the plating tanks 5 and 6, tanks 10 for pre-processing, post-processing, etc. are provided. The substrates P in the cage 7 are parallel to each other and stacked one above the other with a gap 1 in between. Each board P is inclined at an angle D of 45 degrees, for example, the long sides a and b of the board P are horizontal, the short sides c and d are inclined, and the long sides a and b of the car 7 are Horizontal conveyance direction F (processing tank group 9
The car 7 is housed in a position perpendicular to the longitudinal direction of the car 7.

As shown in FIG. 4, which is an enlarged perspective view, the basket 7 includes a rectangular parallelepiped frame 11, and a large number of horizontal shelf-shaped supports supporting the long sides a and b (FIG. 3) of the substrate P on the vertical supports 12 of the frame 11. A member 13 is attached, and a lower end of a vertical member 16 is connected to a longitudinally intermediate portion of both side parts 15 of the upper frame parallel to the transport direction F. The member 16 is provided with a hook 17 at its upper end, and a transport robot (not shown) locks the hook 17 so that the car 7 can be transported up and down and in the direction of arrow F.

In FIG. 3, 20 and 21 are partition walls between the electroplating tank 6 and the tanks 5 and 10 before and after it, 23 is one side wall of the tank 6, and the partition walls 20 and 21 and the bottom wall (not shown) are the side walls. Opposite side to 23 (top right of Figure 3)
The anode 8 with the vertical end wall 25 at the tip protrudes toward the
A storage section 26 is formed. Tank 6 and storage section 26
There is no partition between them, and they communicate with each other. 27 and 28 are protrusions of the partition walls 20 and 21. A plurality of anodes 8 are provided in a plate shape, each inclined in the same direction as the substrate P, and stacked one above the other with a gap l' having the same size as the gap l. The anode 8 is a holder 3 fixed to the edge on the end wall 25 side.
Holder 3 is held in the above position by holder 3.
The upper end of 0 is attached to the extension part 27 using rollers 31, etc.
It is designed to be able to run along the upper edge of 28. 32 is a rail for the roller 31. Although not shown, an anode power source is connected to the holder 30 via a current collecting brush mechanism or a flexible cable, and the holder 30 is moved by a drive mechanism equipped with a motor, a chain, an air cylinder, etc. There is. The number, vertical position, etc. of the anodes 8 are set so that each anode 8 can be inserted into the gap l between the substrates P, P as described later.

When performing the primary copper plating process, first, the basket 7 containing the pretreated printed circuit boards P in the inclined stacked state is immersed in the chemical plating tank 5 for a predetermined time. When the chemical plating is completed, the car 7 is pulled up and conveyed in the direction of arrow F, and then immersed in the electroplating tank 6. Next, the anode 8 advances toward the side wall 23, and as shown in FIG.
Two sheets of anode 8 are inserted. The area of each anode 8 is sufficiently large, and the anodes 8 face each other over substantially the entire surface of each substrate P. When the anode 8 is energized for a certain period of time and electroplating is completed, the anode 8 is retreated into the storage section 26 shown in FIG. 3, and the basket 7 is lifted up and sent to the next process.

As explained above, according to the present invention, a plurality of printed circuit boards P are stacked and housed in the basket 7, and the basket 7 can be immersed in both the chemical plating tank 5 and the electroplating tank 6 in turn, so that the conventional Thus, the work of transferring the substrate P from the basket 1 (FIG. 1) to the rack 2 (FIG. 2) can be eliminated, and both chemical plating and electroplating can be performed continuously. Therefore, manpower can be saved and the substrate P can be prevented from being soiled during transfer. Furthermore, there is no need to divide the conveyance equipment into one for cars and one for racks as in the past, and the equipment can be integrated into one, thereby reducing equipment costs and occupying space. Since the substrates P are stacked, a large number of substrates P can be stored in the basket 7, and compared to the conventional one-rack system where a small number of substrates are processed, it is possible to increase the number of substrates processed each time and improve productivity. .

Since the anode 8 is interposed in the gap l between the substrates P, P, even when a large number of substrates P are stacked, the anode 8 can be placed adjacent to each substrate P. It is possible to improve the plating finish by making the energization state uniform. Since the substrates P are piled up and immersed in the chemical plating tank 5, the processing area for the amount of liquid can be maintained at a required value or more, and deterioration of the load factor can be prevented and a preferable chemical reaction can be carried out.

Apart from the present invention, it is also conceivable to lay the substrates P horizontally and stack them one above the other, or to stack the substrates P vertically, but the present invention has the following advantages over these methods. First, if the substrates P are placed horizontally and stacked one on top of the other, the plating liquid will remain on the horizontal substrates P when the baskets are pulled up from the tanks 5 and 6, making it difficult to be discharged. There is a problem that the substrate P may leak out and mix into another tank, or the substrate P may be immersed in the next plating tank while the plating solution remains on the top surface. On the other hand, when the substrate P is tilted as in the present invention, the plating liquid quickly flows out from the top of the substrate P when it is pulled up.
The above problem does not occur.

When the present invention is compared with the method of making the substrate P vertical, the present invention is superior in terms of the length of the plating tank, the injection nozzle for high-speed plating, etc. as described below.
That is, as shown in Fig. 6, which is a schematic side view, for example, 40
If 12 boards P are arranged in a vertical position with a gap m of mm apart, the length L' of the entire board group in the transport direction will be 40 x 12 = 480 mm, even if the thickness of the boards P is ignored. On the other hand, in the 45° inclination method according to the present invention, for example, the fifth
As shown in the figure, the length L of the entire board group in the transport direction is (short side d
Length: e.g. 500mm)×1/√2=500/√2mm
Therefore, it becomes extremely short. Therefore, according to the present invention, the length of each plating tank and the total length of the plating tank group 9 can be made shorter, and the installation area of the plating tank group 9 in a factory can be reduced.

The high-speed plating nozzle 40 is installed, for example, in the vicinity of the partition wall 21 in FIG.
A plating liquid drain 41 is provided near the lower end of the plating liquid. When the nozzle 40 for high-speed plating is arranged, new plating liquid can be constantly supplied to the surface of the substrate P, so the plating processing time can be shortened, and in the present invention, such a nozzle 40 can be installed without problems. It becomes possible. On the other hand, in the vertical system shown in Fig. 6, the nozzle 40 must be installed directly above the gap m, but if this is done, the nozzle 40 will get in the way and the car cannot be raised or lowered. Installation of the nosol 40 is practically impossible. In the vertical method, it is conceivable to install the nozzle 40 near the side wall 23 and spray the plating liquid parallel to the long side b of the substrate as shown in FIG. b (e.g. 1500mm)
is much longer than the short sides c and d (generally 500 mm or less), so in the method shown in Figure 7, the flow rate of the plating liquid will be uneven between the short sides c and d, making it difficult to perform plating uniformly. I can't finish it.

In the case of embodying the present invention, an anode 8 is placed on standby above the electroplating tank 6 as shown in FIG. After electroplating is completed, the board P is placed in tank 6.
After pulling the anode 8 above the substrates P, P
You can also pull it out from between.

[Brief explanation of drawings]

1 and 2 are schematic perspective views of a conventional basket and rack, FIG. 3 is a perspective view of a device according to the invention, and FIG.
The figure is an enlarged view of the cage, FIG. 5 is a schematic side view of the device in an anode-interposed state, FIG. 6 is a schematic side view of the device other than the present invention, and FIG. 7 is the same as in FIG.
The arrow view, FIG. 8 is a side view of another embodiment according to the present invention. 5...Chemical plating tank, 6...Electro plating tank, 7
...basket, 8...anode, (positive electrode), l...gap, P...printed board.

Claims (1)

[Scope of Claims] 1. A plurality of printed circuit boards are stored in a basket in an inclined position and stacked vertically with a gap between them, and the basket is immersed in a chemical plating bath to chemically plate the printed circuit boards, and then the basket is placed in a basket. A printed circuit board characterized in that an electrode for electroplating is interposed in the gap between the printed circuit boards in the basket, and then electroplating is performed in an electroplating bath with the printed circuit boards housed in the basket. Primary copper plating method. 2. A basket containing a plurality of printed circuit boards stacked one above the other with a gap between them in an inclined position, a chemical plating tank and an electroplating tank for primary copper plating into which the cage is immersed, and the above-mentioned gap between the printed circuit boards. 1. A device for primary copper plating of printed circuit boards, comprising an interposed electroplating electrode.