JPH0765209B2 - Electroplating equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electroplating apparatus capable of performing plating in a short time.

(Prior Art) In the past, when electroplating was performed, the object to be plated was immersed in a plating solution, but simple immersion takes time, so electroplating is performed while flowing the plating solution. A high-speed electroplating method has been proposed (for example, Japanese Patent Publication No. 60-1958, which is the application of the applicant).

(Problems to be Solved by the Invention) When the plating method as described above is applied to a plated material that constitutes a printed wiring board, for example, the plating solution flowing along each surface of the plated material causes Predetermined plating is applied in a short time. By the way, a large number of through-holes having a small diameter are formed in the plate material to be plated for connection of electric component terminals and the like, and these through holes penetrate through the plate material in the plate thickness direction. Therefore, in the above plating method, the plating solution settles in the through holes,
There is an inconvenience that it takes a long time to perform a predetermined plating on the inner peripheral surface of the through hole. Therefore, a fluid pressure difference is generated between the surface plating solutions at the respective ends of the through holes so that the plating solution is forced to flow in the through holes, whereby the inner peripheral surface of the through holes is also short. It is also proposed that the plating be performed in time.

However, in the above configuration, a part of the plating solution may flow in a place far from the plate material to be plated, resulting in useless flow, which may lead to plating in a short time.

Furthermore, the plating solution may become non-uniform unless it is sufficiently mixed and more homogenized before being used for plating.

(Object of the Invention) The present invention has been made by paying attention to the above circumstances, and when plating a plate material having a large number of through holes which constitutes a printed wiring board, an inner peripheral surface of the through holes is formed. Also, the purpose is to allow a predetermined plating to be performed in a short time.

In addition, it is possible to prevent unnecessary flow of a part of the plating solution that flows away from the plate material to be plated, and to perform plating in a shorter time.
The purpose of the present invention is to sufficiently mix and further homogenize with a simple constitution before subjecting to plating.

(Structure of the Invention) A feature of the present invention for achieving the above-mentioned object is to provide the plate material to be plated so that the plate material to be plated partitions the plating chamber into a first plating chamber and a second plating chamber. A first supply of a plating solution into the first plating chamber at one end of the first plating chamber in the longitudinal direction of the cross-sectional shape of the plating plate material
The supply passage is connected, and the other end is connected with a first discharge passage for discharging the plating solution in the first plating chamber, while the one end of the second plating chamber is connected with the plating solution in the second plating chamber. A second supply passage that connects the second supply passage and discharges the plating solution in the second plating chamber to the other end.
Connecting the discharge passages, projecting each electrode from the inner wall surface of the plating chamber to the vicinity of each surface of the plate material to be plated, and the gap between the protruding end surface of each electrode and each surface of the plate material to be plated. From the first and second supply passages,
A flow path of the plating solution flowing toward the second discharge passage, the flow rates of the plating solution flowing through the first and second supply passages are variable, and the first and second plating chambers are provided. The above-mentioned electrodes are located on the extension of the hole core of each opening of the second supply passage.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

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

In the figure, the printed wiring board 1 includes a substrate material 2 made of glass fiber reinforced epoxy resin, a wiring circuit portion 3 formed on both surfaces of the substrate material 2, and both wiring circuit portions 3 penetrating the substrate material 2. , 3 is connected to the connection circuit section 4.
Both sides of the substrate material 2 have lands 5 for connecting components such as ICs.
It is covered with a solder resist 6 made of a heat resistant resin. This solder resist 6 is used when soldering the above-mentioned components onto the printed wiring board 1 by soldering the solder paste 5
Besides, it prevents unnecessary attachment and improves the insulating property of the printed wiring board 1.

The wiring circuit section 3 is formed by depositing thin first copper layers 8 on both sides of the substrate material 2 and a thick second copper layer 8 on each of the first copper layers 8 and being integrated with the first copper layers 8. It has a copper layer 9 and a solder layer 10 which covers the first copper layer 8 and the second copper layer 9 and promotes soldering. Further, the connection circuit portion 4 has a through hole 13 penetrating in the board thickness direction in the substrate material 2, and the inner peripheral surface of the through hole 13 is similar to the wiring circuit portion 3 in the first copper layer 8 , A second copper layer 9 and a solder layer 10 are provided.

Next, a procedure for manufacturing the printed wiring board 1 will be described with reference to FIGS. 3 to 10. The method for manufacturing the printed wiring board 1 is called a semi-additive method.

In FIG. 3, the substrate material 2 is a catalyst-containing laminated plate of a reducing substance. Then, palladium or the like is adsorbed on the surface of the substrate material 2 by the reducing substance, thereby providing activation as a pretreatment for plating.

Next, as shown in FIG. 4, the first copper layer 8 is deposited and adhered to the surface of the substrate material 2 by electroless copper plating, whereby the first intermediate molded product 14 is molded. In this case, the thickness of the first copper layer 8 is 2 to 5 .mu.m, so that the surface of the first intermediate molded product 14 is given conductivity. Further, a new through hole 13 'is formed here by plating the inner peripheral surface of the through hole 13.

Next, as shown in FIG. 5, the photosensitive dry films 15 and 15 are pressure-bonded to both surfaces of the first intermediate molded product 14 by heating and pressing. Further, by exposing and developing a circuit pattern corresponding to the wiring circuit portion 3 on both of these dry films 15 and 15, circuit pattern grooves 16 and 16 are formed in these both dry films 15 and 15, respectively. This is the second intermediate molded product 18 which is the plate material to be plated.

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

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

Next, as shown in FIG.
The dry film 15 is peeled from the intermediate molded product 20, and then the first copper layer 8 at 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, and the solder layer 10 covers the first copper layer 8 and the second copper layer 9. .

Then, as shown in FIG. 10 already described, the solder resist 6 in which holes for the lands 5 are formed on both surfaces of the substrate material 2 of the fifth intermediate molded product 21 in the same manner as the dry film 15 is formed.
Is crimped. This completes the production of the printed wiring board 1.

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

First, the apparatus used for the plating will be described.

FIG. 2 shows a flow sheet of the electrolytic copper plating apparatus 24. The electrolytic copper plating device 24 supplies a main body 25 for electroplating the second intermediate molded product 18 as the plate material to be plated, and an acidic copper plating solution P such as copper sulfate in a plating solution tank 26 to the main body 25. A plating solution supply means 27 is provided.

The plating solution supply means 27 has a pump 28, and this pump
A suction side of 28 is connected to the plating solution tank 26, and a supply side header 30 is connected to a discharge side of the pump 28. The plating solution P for the supply header 30 and the main body 25
The inlet side is communicated with the first supply passage 31 and the second supply passage 32. The outlet side of the plating solution P of the main body 25 is connected to the discharge side header 35 by the first discharge passage 33 and the second discharge passage 34, and the discharge side header 35 is connected to the plating solution tank 26.

A first solenoid valve 37 for fully opening and closing the first supply passage 31 is provided in the middle of the first supply passage 31, and a first manual valve for adjusting the opening degree of the first supply passage 31. Valve 38
Is provided between the supply side header 30 and the first solenoid valve 37. 39 is a first flow meter for measuring the flow rate of the plating solution P in the first supply passage 31.

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

The main body 25 will be described with reference to FIG.

The inside of the housing 43 of the main body portion 25 is a plating chamber 49, and a pair of electrodes 44, 44 are provided in the plating chamber 49, and both electrodes 44 serve as an anode (reference numeral 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 the 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. Further, support fittings 45, 45 for supporting the second intermediate molded product 18 are arranged in the housing 43, and both of the support fittings 45, 45 are cathodes (reference numeral is shown in FIG. 1). The second intermediate molded product 18 has a first plating chamber 49 formed by the support fittings 45, 45 at approximately the center between the electrodes 44, 44.
The plating chamber 46 and the second plating chamber 47 are mounted so as to be separated from each other.

Particularly, in FIG. 1, at the one end (right end) of the first plating chamber 46 in the longitudinal direction of the sectional shape of the second intermediate molded product 18 (in the left-right direction toward FIG. 1), The first supply passage 31 is connected to the inside of the first plating chamber 46 with the first supply passage 31, and the other end portion (left end portion) is configured to discharge the plating liquid P inside the first plating chamber 46. 33 are connected. On the other hand, in the same as above, the second supply for supplying the plating solution P into the second plating chamber 47 at one end (right end) of the second plating chamber 47 in the longitudinal direction of the sectional shape of the second intermediate molded product 18. The passage 32 is connected, and the second discharge passage 34 for discharging the plating solution P in the second plating chamber 47 is connected to the other end (left end).

The respective electrodes 44 are made to project from the inner wall surface of the plating chamber 49 facing the respective surfaces of the second intermediate molded product 18 to the vicinity of the respective surfaces of the second intermediate molded product 18 as above. The gap between the projecting end surface of the second intermediate molded product 18 and each surface of the second intermediate molded product 18 flows from the first supply passage 31 and the second supply passage 32 toward the first discharge passage 33 and the second discharge passage 34. The flow paths 51, 51 for the liquid P are used.

Further, in the above case, the hole core 5 of each opening of the first supply passage 31 and the second supply passage 32 into the first plating chamber 46 and the second plating chamber 47.
The electrodes 44, 44 are located on the extension of 2, 53.

Then, the main body portion 25 is driven from the plating solution tank 26 through the first supply passage 31 and the second supply passage 32 by driving the pump 28.
When the plating solution P is supplied to the above, the plating solution P once collides with each of the electrodes 44, 44 and disturbs its flow, whereby the plating solution P is provided for plating in the flow paths 51, 51. Before, it was well mixed and more homogenized.

Next, the plating solution P passes through the flow paths 51, 51,
That is, along each surface of the second intermediate molded product 18, the first
The fluid flows toward the discharge passage 33 and the second discharge passage 34.

Further, a hydraulic pressure difference is generated between the plating solutions P in the first plating chamber 46 and the second plating chamber 47. That is, the opening of the first supply passage 31 is increased by operating the first manual valve 38. Therefore, the flow rate of the plating solution P flowing through the first supply passage 31 is large, and the flow velocity at this time is, for example, 4 m / s (reference numeral F _{1 in the} figure). In this case, since the pressure loss at the first manual valve 38 is small, the pressure of the plating solution P is kept large.

On the other hand, the opening degree of the second supply passage 32 is reduced by operating the second manual valve 41. Therefore, this second supply passage
The flow rate of the plating solution P flowing through 32 is small, and the flow velocity at this time is, for example, 3.0 m / s (indicated by symbol F _{2 in the} figure). in this case,
Since the pressure loss at the 24th manual valve 41 is large, the pressure of the plating solution P becomes small.

Then, since the first plating chamber 46 and the second plating chamber 47 have different pressures, the plating solution P flows from the first plating chamber 46 having a high pressure to the second plating chamber 47 having a low pressure through the through hole 13 '. It will flow (see symbol F _{3 in the} figure).

Therefore, the surface of the first copper layer 8 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 as a whole. Therefore, when electrolytic copper plating is performed on the surface of the second intermediate molded product 18, on the first copper layer 8 of the circuit pattern groove 16 of the second intermediate molded product 18,
The second copper layer 9 having the same thickness is plated on the inner peripheral surface of the first copper layer 8 of the through hole 13 'in a short time.

(Effect of the Invention) According to the present invention, the plated plate material is provided so that the plated plate material partitions the plating chamber into the first plating chamber and the second plating chamber, and in the longitudinal direction of the cross-sectional shape of the plated plate material, A first supply passage for supplying a plating solution into the first plating chamber is connected to one end of the first plating chamber, and a first discharge passage for discharging the plating solution in the first plating chamber is connected to the other end. On the other hand, at the end of the second plating chamber, the second plating chamber
A second supply passage for supplying a plating solution into the plating chamber is connected, and a second discharge passage for discharging the plating solution in the second plating chamber is connected to the other end of the plating chamber so that the inner wall surface of the plating chamber can be used for plating. Each electrode is projected to the vicinity of each surface of the plate material, and the gap between the projecting end surface of each electrode and each surface of the plate material to be plated is set from the first and second supply passages to the first and second supply passages. It serves as a flow path for the plating solution that flows toward the discharge path.

Therefore, the plating solution supplied to the plating chamber from the first and second supply passages flows through each flow passage, that is, along each surface of the plate material to be plated. Therefore, it is possible to prevent wasteful flow of a part of the plating solution flowing in a place far from the plate material to be plated. Therefore, the plating is applied in a short time accordingly. Further, as described above, since the unnecessary flow of the plating solution is prevented, the accuracy of flow rate control is improved,
The plating accuracy is improved, and the plating solution can be reduced, so that the plating chamber can be made compact.

Further, since the flow rates of the plating solutions flowing through the first and second supply passages are made variable, the flow rates of the plating solutions in the respective flow passages are made different so that the plating solutions at both ends of the through-holes are separated from each other. A pressure difference can be created. Therefore, since the plating solution is forced to flow in the through hole due to the difference in the liquid pressure, electroplating is performed in a short time even on the inner peripheral surface of the through hole.

Furthermore, since each of the electrodes is located on the extension of the hole core of each opening of the first and second supply passages into the first and second plating chambers, the first and second supply passages pass through the first and second supply passages. The plating solution that has flowed into the second plating chamber once collides with each of the electrodes and is disturbed in its flow. Therefore, since the plating solution is sufficiently mixed and homogenized in the above-mentioned flow path before being used for plating, the plating by this plating solution is also uniform, and in terms of product quality. preferable.

Moreover, as described above, since the plating solution is homogenized by using the electrodes, it is sufficient to provide no additional member for homogenization, so that the structure of the plating apparatus is simplified.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 is an enlarged sectional view of a 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 show printed wiring boards. It is explanatory drawing of a manufacturing procedure. 13 '... Through hole, 18 ... Second intermediate molded product (plate material to be plated), 24 ... Electrolytic copper plating device, 25 ... Main body part, 31 ...
First supply passage, 32 ... Second supply passage, 33 ... First discharge passage, 34 ... First discharge passage, 43 ... Housing, 44 ... Electrode, 46 ... First plating chamber, 47 ... Second plating room, 49 ……
Plating chamber, 51 ... Flow path, 52,53 ... Hole core, P ... Plating solution.

Claims (1)

[Claims] 1. A plate material to be plated having a through hole penetrating in the plate thickness direction is dipped in a plating solution stored in a plating chamber, and a pair of electrodes is dipped in the plating solution so as to sandwich the plate material to be plated. In the electroplating apparatus configured to perform electroplating on the plate material to be plated while flowing the plating solution, the plate material to be plated is divided into a first plating chamber and a second plating chamber. A plate member is provided, and a plating solution is supplied into the first plating chamber at one end of the first plating chamber in the longitudinal direction of the cross-sectional shape of the plate member to be plated.
The supply passage is connected, and the other end is connected with a first discharge passage for discharging the plating solution in the first plating chamber, while the one end of the second plating chamber is connected with the plating solution in the second plating chamber. A second supply passage that connects the second supply passage and discharges the plating solution in the second plating chamber to the other end.
The discharge passages are connected to each other so that each of the electrodes is projected from the inner wall surface of the plating chamber to the vicinity of each surface of the plate material to be plated, and the protruding end surfaces of each electrode and each surface of the plate material to be plated are The gap is a flow path of the plating solution flowing from the first and second supply passages toward the first and second discharge passages, and the flow rates of the plating solutions flowing through the first and second supply passages are variable, Further, the electroplating apparatus is characterized in that each of the electrodes is located on an extension of a core of each opening of the first and second supply passages into the first and second plating chambers.