JPS62136588A - High-speed electroplating method - Google Patents

Abstract

PURPOSE:To pass a plating liquid along the surface of a sheet material to be plated having through-holes and to quickly plate said material by segmenting a plating chamber to two chambers by said sheet material and generating a liquid pressure difference between the plating liquids of the two chambers in the stage of subjecting the above-mentioned sheet material to electroplating. CONSTITUTION:The sheet material 18 to be plated having the through-holes 13' is immersed into the plating liquid in the plating chamber 49. The plating chamber 49 is segmented to the 1st plating chamber 46 and the 2nd plating chamber 47 by the above-mentioned sheet material 18. The liquid pressure difference is then generated between the plating liquids of the two chambers 46, 47. The electroplating is executed while the plating liquid is passed from the higher pressure side to the lower pressure side through the through-holes 13'.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a high-speed electroplating method that allows plating to be performed in a short time.

(Conventional technology) Conventionally, when electroplating was performed, the object to be plated was immersed in a plating solution, but since mere immersion takes time, electroplating is performed while the plating solution is flowing. High-speed electroplating methods have been proposed (for example, Japanese Patent Publication No. 1988-1958 filed by the same applicant).

(Problems to be Solved by the Invention) When the above-mentioned plating method is applied to plate materials constituting, for example, printed wiring boards, the plating solution flowing along each surface of the plate materials causes damage to these surfaces. Predetermined plating will be applied in a short time. By the way, a large number of small diameter through holes are formed in the plate material to be plated for connection of electrical component terminals, etc., and these through holes are formed to be substantially perpendicular to the surface of the plate material to be plated.

For this reason, in the above-mentioned plating method, the plating solution stagnates inside the through-hole, resulting in the inconvenience that it takes a long time to apply a predetermined plating to the inner peripheral surface of the through-hole.

(Objective of the Invention) The present invention was made in view of the above-mentioned circumstances, and when plating a plate material having a large number of through holes such as a printed wiring board, the inner circumferential surface of the through holes is The purpose is to enable a specified plating to be performed in a short time.

(Structure of the Invention) A feature of the present invention for achieving the above object is that the plating chamber is divided into two chambers by the plate material to be plated, and the plating liquid in both chambers is separated by the plate material to be plated. The point is that it creates a hydraulic pressure difference.

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

First, the completed printed wiring board 1 will be explained with reference to FIG.

In the figure, the printed wiring board l is glass! A substrate material 2 made of fiber-reinforced epoxy resin, a wiring circuit section 3 formed on both sides of this substrate material 2, and a connection circuit section 4 that penetrates the substrate material 2 and connects the rewiring circuit section 3.3. It has Both surfaces of the substrate material 2 are covered with a heat-resistant resin solder resist 6, leaving lands 5 for connecting parts such as ICs. This solder resist 6 prevents solder from adhering to areas other than the lands 5 unnecessarily when the above-mentioned components are soldered onto the printed wiring board 1, and also improves the insulation properties of the printed wiring board 1.

The wiring circuit section 3 includes a thin first copper layer 8 plated on both sides of the substrate material 2, and a thick second copper layer 8 plated on each of the first copper layers 8 and integrated with the first copper layer 8. It has a copper layer 9 and a solder layer 10 that covers the first copper layer 8 and the second copper layer 9 to promote soldering. Further, the connection circuit section 4 has a through hole 13 formed in the substrate material 2, and the inner peripheral surface of the through hole 13 has a first
Copper layer 8. A second copper layer 9 and a solder layer 10 are provided.

Next, the manufacturing procedure of the printed wiring board 1 will be explained with reference to FIGS. 3 to 1O. This printed wiring board
The manufacturing method is called a semi-additive method.

In FIG. 3, the substrate material 2 is a catalytic laminate of a reducing substance. Then, palladium or the like is adsorbed onto the surface of the substrate material 2 by the binary substance, thereby providing activation as a plating pretreatment.

Next, as shown in FIG. 4, a first copper layer 8 is deposited and adhered to the surface of the substrate material 2 by electroless copper plating, whereby a first intermediate molded product 14 is formed. in this case,
The thickness of the first copper layer 8 is 2 to 5 μl, thereby imparting electrical conductivity to the surface of the first intermediate molded product 14.

Further, by plating the inner peripheral surface of the through hole 13, a new through hole 13' is formed here.

Next, as shown in FIG. 5, photosensitive dry films 15.15 are bonded to both surfaces of the first intermediate molded product 14 by heating and pressing. Further, a circuit pattern corresponding to the wiring circuit section 3 is exposed on both of these dry films 15 and 15,
By developing both these dry films 15.1
5 are formed with circuit pattern grooves 16 and 16, respectively.

This is the second intermediate molded product 18 which is a plate material to be plated.

Next, as shown in FIG. 6, electrolytic copper plating is applied to the first copper layer 8 of the circuit pattern groove 16 of the second intermediate molded product 18 and the first copper layer 8 of the inner peripheral surface of the through hole 13'. A second copper layer 9 is deposited on top and adheres closely. This is the third intermediate molded product 19.

Next, as shown in FIG. 7, a solder layer 10 is deposited and adhered to the second copper layer 9 of the third intermediate molded product 19 by electro-solder plating, and this is the fourth intermediate molded product 20. .

Next, as shown in FIG.
The dry film 15 is peeled off from the intermediate molded product 20, and then the first copper layer 8 is removed from the peeled portion of the dry film 15.
is removed by etching with an aqueous solution of cupric chloride or the like.

This is the fifth intermediate molded product 21.

Next, as shown in FIG. 9, the fifth intermediate molded product 21 is heated to melt the solder layer 10.
covers the first copper layer 8 and the second copper layer 9.

Then, as shown in FIG. 10 already explained, the fifth
The dry film 1 is applied to both sides of the substrate material 2 of the intermediate molded product 21.
The solder resist 6 in which holes for the lands 5 are formed is crimped in the same manner as in 5. This completes the production of the printed wiring board l.

The electrolytic copper plating of the second intermediate molded product 18 during the manufacturing procedure of the printed wiring board 1 will be explained in detail with reference to FIGS. 1 and 2.

First, the apparatus used for the above plating will be explained.

FIG. 2 shows a flow sheet of the electrolytic copper plating apparatus 24. This electrolytic copper plating device 24 has a main body portion 2 for electroplating the second intermediate molded product 18 which is the wave plated plate material.
5, and a plating solution supply means 27 for supplying an acidic steel plating solution P such as copper sulfate from a plating solution tank 26 to the main body portion 25.

The plating solution supply means 27 has a pump 28 , and the suction side of the pump 28 is connected to the plating solution tank 26 , and the discharge side of the pump 28 has a supply header 30 .
will be contacted. To this supply side, the blowfish 30 and the main body part 2
It communicates with the plating solution P inlet side of No. 5 through a first supply passage 31 and a second supply passage 32. In addition, this main body portion 25
The outlet side of the plating solution P is connected to a discharge side header 35 through a first discharge passage 33 and a second discharge passage 34, and this discharge side header 35 is connected to the plating solution tank 26.

Further, a first solenoid valve 37 for fully opening and fully closing the first supply passage 31 is provided in the middle of the first supply passage 31, and a first manual valve 37 for adjusting the opening degree of the first supply passage 31 is provided. A valve 38 is provided between the supply header 30 and the first solenoid valve 37 . Reference numeral 39 denotes a first flow meter that measures the flow rate of the plating solution P in the first supply passage 31.

On the other hand, a second electromagnetic valve 40, a second manual valve 41, and a second flow meter 42 are also provided in the middle of the second supply passage 32 in the same manner as described above.

Further, the main body portion 25 will be explained with reference to FIG.

Inside the housing 43 of the main body part 25 is a plating chamber 49, and a pair of electrodes 44, 44 are provided in the plating chamber 49, and these electrodes 44 are designed to serve as anodes (as shown in FIG. 1). It is connected to a power supply device (not shown). The electrodes 44, 44 are arranged at a predetermined interval, and the gap between these electrodes 44, 44 extends so as to connect the inlet side and the outlet side of the plating solution P in the main body 25. Furthermore, a support fitting 45.45 for supporting the second intermediate molded product 18 is disposed within the housing 43, and both of these support fittings 45.4
5 is a cathode (illustrated in Fig. 1). The second intermediate molded product 18 is mounted approximately at the center between the electrodes 44, 44 so that the plating chamber 49 is partitioned into a first plating chamber 46 and a second plating chamber 47 by the support fittings 45, 45.

The first plating chamber 46 includes the first supply passage 31 and the first plating chamber 46 .
The second supply passage 32 and the second discharge passage 34 are connected to the other second plating chamber 47 .

The plating solution tank 2 is then driven by the pump 28.
When plating solution P is supplied from 6 to main body portion 25 through first supply passage 31 and second supply passage 32, plating solution P flows along the surface of second intermediate molded product 18.

Further, a liquid pressure difference is created between the plating solution P in the first plating chamber 46 and the second plating chamber 47. That is, by operating the first manual valve 38, the opening degree of the first supply passage 31 is increased. Therefore, the flow rate of the plating tank P flowing through this first supply passage 31 is large, and the flow rate at this time is, for example, 4 rags (indicated by reference numeral F1 in the figure). In this case, the pressure loss at the first manual valve 38 is small. Therefore, the pressure of this plating solution P is kept high.

On the other hand, by operating the second manual valve 41, the second supply passage 3
The opening degree of No. 2 is set small. Therefore, the flow rate of the plating solution P flowing through the second supply passage 32 is small, and the flow velocity at this time is, for example, 3.0 m/s (indicated by reference numeral F2 in the figure). In this case, since the pressure loss at the second manual valve 41 is large, the pressure of the plating solution P becomes small.

Then, since the pressures are different between the first plating chamber 46 and the second plating chamber 47, the plating solution P passes through the through hole 13' from the first plating chamber 46 where the pressure is high to the second plating chamber 47 where the pressure is low. It will flow (indicated by reference numeral F3 in the figure).

Therefore, the entire surface of the first copper layer 8 that is not covered with the dry film 15 on the surface of the second intermediate molded product 18 comes into contact with the new plating solution P. Therefore, when performing electrolytic copper plating on the surface of this second intermediate molded product 18, the first part of the circuit pattern groove 16 of this second intermediate molded product 18
A second copper layer 9 having a similar thickness is plated on the copper layer 8 and on the inner peripheral surface of the first copper layer 8 in the through hole 13' in a short time.

(Effects of the Invention) According to the present invention, since the plating solution is made to flow along the surface of the plate material to be plated, both sides of the plate material to be plated can be plated in a short time. In addition, because a liquid pressure difference was created between the two plating solutions separated by the plate material, the plating solution passed through the through hole from the high pressure side to the low pressure side between the two plating solutions separated by the plate material. Therefore, it will flow. Therefore, electroplating is promoted also on the inner peripheral surface of the through hole of the plate material to be plated.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, in which Fig. 1 is an enlarged sectional view of the main body of an electrolytic copper plating apparatus, Fig. 2 is a flow sheet of the electrolytic copper plating apparatus, and Figs. 3 to 10 are diagrams of a printed wiring board. It is an explanatory diagram of a manufacturing procedure. 13'... Through hole, 18... Second intermediate molded product (plate material to be plated), 24Φ, electrolytic copper plating device, 25... Main body, 49... Plating chamber, P... Plating solution.

Claims (1)

[Claims] 1. When electroplating a plate material to be plated having a through hole in the plating solution stored in the plating chamber and flowing the plating solution, the plate material to be plated is placed in the plating chamber. A high-speed electroplating method characterized by dividing the plating solution into chambers and creating a liquid pressure difference between the plating solutions in both chambers separated by the plate material to be plated.