JPH0356696A - Wet electroplating device - Google Patents

Abstract

PURPOSE:To circulate a plating soln. through a tiny through hole and to uniformly plate the inner surface of the tiny through hole by arranging a printed board having the tiny through holes vertically in a plating soln. and applying a DC current to the electrodes set on both sides of the board. CONSTITUTION:The printed board 7 having through holes 7a is vertically arranged with a fixing jig 5 in the plating soln. 11 contg. copper sulfate and acidified with sulfuric acid, a couple of electrodes 2 and 2 are set on both sides, and a current is applied from a DC power source 12 with the board 7 as a cathode and the electrodes 2 and 2 as the anodes. The SO4<2-> ion and OH<-> ion generated by electrolysis pass through the through holes 7a to form an electrolytic line, a couple of electrodes 8 and 9 are further arranged outside the electrodes 2 to form another through-hole electrolytic line 10, and a current is applied to both lines. Consequently, Cu<2+> ion is supplied to the through hole 7a, the inside of the through hole 7a is uniformly plated with Cu, and the conductors on both sides of the board 7 are electrically connected through the through hole 7a.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a wet electrolytic treatment apparatus for treating a printed circuit board having micropores by this method.

[Conventional technology]

Conventionally, when processing a workpiece having minute through-holes using a wet method, the smaller the diameter of the holes, the more the processing effect (hereinafter referred to as
(simply written as ``t night'') is difficult to enter, and there are areas that cannot be treated because air bubbles accumulate in the holes and the liquid cannot come into contact with the inside of the holes, or even if the liquid enters the micropores and the air bubbles escape. There was a problem in that it was difficult to exchange the fluid inside the hole with fresh fluid from outside.

In printed circuit boards, a particular problem is the wet processing process for electrically connecting conductors on both sides through holes, and this process can be broadly divided into hole cleaning, degreasing, catalyticization, electroless copper plating, and electroplating. It is generally made of copper plating. Since all of these treatments, including washing with water and hot water, are performed using a hot method, it is important to solve the above-mentioned problems, especially in the case of substrates having micropores.

[Problem to be solved by the invention 1] As a device for solving these problems,
Those disclosed in Japanese Patent Publication No. 210694, Japanese Patent Publication No. 61-479l8, Japanese Patent Publication No. 9036 Sho 63, etc. have been proposed.

The first proposal (Japanese Unexamined Patent Publication No. 61-210694) is to separate the processing liquid on both sides of the substrate by the substrate, allow the liquid to flow through holes, and then pressurize the liquid on both sides of the substrate alternately. This is a device that allows liquid to flow.

The second proposal (Japanese Patent Publication No. 61-47918) is an apparatus in which the liquid flows down and the liquid is caused to flow into the hole by causing pressurization and negative pressure to be generated on the substrate surface by a liquid flow turbulent member.

The third proposal (Japanese Patent Publication No. 63-9036) is a device that uses a nozzle to impinge a high-speed liquid stream on a hole to cause the liquid to flow into the hole.

However, in the conventional example described above, the first proposal uses a device that allows liquid to flow into the hole using pressurized flow, so it is necessary to devise measures to prevent liquid from leaking inside the device, making the structure complicated. Furthermore, there were other drawbacks such as problems with the pressure resistance of the object to be treated. In the second proposal, although it is not necessary to have a sealed structure, the effect of pressurization and negative pressure is small if only the liquid is allowed to flow down, and in a substrate with micropores, the liquid is made to flow by the pressure difference generated on both sides of the substrate. is insufficient.

In addition, in the third proposal, although it is possible to generate a pressure difference by ejecting a high-speed liquid flow from a nozzle that is sufficient to push out the liquid in the micropores, it is a method that causes the liquid to collide perpendicularly to the substrate. In order to push the material into the hole, it is desirable to bring the nozzle close to the substrate and make the nozzle diameter smaller than the hole diameter. However, the more pressure is applied, the more the substrate will move away from the nozzle, so In addition, it was necessary to provide a suitable support to prevent the substrate from warping.However, in both methods, when the hole diameter is 0.1 mm, it is difficult to obtain liquid flow using pressure. If this was attempted, the fluidity of the liquid would become extremely poor, making it practically impossible.

The present invention has been made to solve the above-mentioned problems, and provides a wet electrolytic treatment apparatus that can smoothly flow a treatment liquid into micropores provided in a workpiece by a simple means. The purpose is to

[Means to solve the problem]

In order to solve the above-mentioned problems, the wet electrolytic treatment apparatus of the present invention provides a wet electrolytic treatment apparatus in which, when a workpiece having micropores is treated by a wet method, a liquid flows through the workpiece through the micropores of the workpiece. A pair of electrodes are arranged on both sides of the object to be processed.

[Function] According to the present invention, it is possible to easily flow the liquid in the pores of a workpiece having micropores using an electrochemical method.

That is, by arranging the object to be treated so that only the ions can pass through it, and by arranging a pair of electrodes to sandwich the object and electrolyzing it, the ions pass through the micropores, and the target ions are generated. It is configured to be supplied into the microhole. The solution in this case is a liquid containing an electrolyte for the amount of ion transfer, and the electrolysis method may be any method such as direct current, alternating current, pulse method, etc. However, although it is desirable that only the micropores are the ion passages in the arrangement of the object to be treated, the effect will not be sufficient even if there is some gap for ions to pass through from the bottom or side of the object. Demonstrated.

Furthermore, in through-hole plating of printed circuit boards etc. that have minute holes, the printed circuit board to be processed is arranged so that ions pass through the through-holes in the same manner as described above, and the opposite sides are electrically connected. Installed to sandwich the object to be processed. Thereafter, by appropriately electrolyzing this system, ions are supplied into the pores of the object to be treated, and through-hole plating is uniformly and satisfactorily deposited within the pores.

In addition, when electrolyzing each system, it is possible to energize them at the same time, to energize them mutually, and to change the polarity at any time using an electrode separate from the object to be treated, etc., either singly or in combination. This allows ions to move more smoothly.

【Example〕

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

FIG. 1 is a schematic cross-sectional view showing an embodiment device according to the present invention;
FIG. 2 is an enlarged view of the main part of FIG. 1 for explaining this embodiment.

The apparatus shown in FIG. So. The aqueous solution 4 is separated into an anode chamber 2a and a cathode chamber 1a by fixing the object 6 having micropores in the aqueous solution 4 with the object fixing jig 5. 1a is provided with a cathode 1, and by connecting these electrodes to a power source 3 and energizing them, as shown in FIG. 2, so.
”- ions and OH- ions form the micropores 6a of the object 6.
, and move to the anode 2 side, so that the microhole 6a serves as an ion passage.

In this way, the liquid can flow smoothly in the micropores 6a of the object to be treated 6, the air bubbles in the holes can also flow, and the processing liquid can pass through the pore walls.

Next, an example of through-hole plating processing will be described with reference to FIG.

FIG. 3 is a schematic cross-sectional view of a through-hole plating apparatus for a printed circuit board having microholes.

A sulfuric acid acid solution containing copper sulfate is used as the electrolyte 11, the electrolyte is separated by fixing the printed circuit board 7 with a fixing jig 5, an anode 2 is provided in the compartment, and a DC power source 12 is installed with the printed circuit board side as a cathode. By connecting and energizing, the ion flow generated by electrolysis passes through the through-hole holes 7a, forming an electrolytic system path for the through-holes. Furthermore, a pair of electrodes 8 and 9 are provided to form a through-hole plating electrolytic system path 10 separate from the above-mentioned through-hole electrolytic system path, and by appropriately supplying current to each electrolytic system path, Cu'' ions are supplied to the through-hole holes 7a. Then, plating is deposited inside the through-hole holes 7a.

The electrolytic conditions for the through-hole electrolytic system line 12 and the other through-hole plating electrolytic system line 10 are, for example, as shown in FIG. An AC pulse waveform 10a is supplied from each path, and the supplies from each path are staggered with respect to each other.

Thus, in through-hole plating of a printed circuit board having microholes, the printed circuit board as the object to be processed is arranged so that ions pass through the through-hole hole 7a,
By electrically connecting the counters and installing the object to be processed between them, and electrolyzing the system appropriately, ions are supplied into the through-hole holes 7a of the printed circuit board 7, and the through-hole plating is uniformly applied inside the holes. It is deposited quickly and well.

In this embodiment, the ions can be moved more smoothly by changing the polarity at any time using an electrode separate from the printed circuit board that is the object to be processed.

[Effects of the Invention] As described above, according to the present invention, the processing liquid can be effectively caused to flow into the micropores provided in the object to be processed using simple means. Furthermore, the present invention can be applied to through-hole plating of printed circuit boards and the like having minute holes, and the through-hole plating can be deposited uniformly and satisfactorily within the holes.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view showing an embodiment of the device according to the present invention, Fig. 2 is an enlarged view of the main part of Fig. 1 to explain the embodiment, and Fig. 3 is a print having micropores. FIG. 4 is a schematic cross-sectional view of a through-hole plating apparatus for a substrate, and is a diagram showing electrolytic conditions of the apparatus shown in FIG. 3. 1... Cathode 2... Anode 3... Power supply 4... Electrolytic solution 5... Processing object fixing jig 6... Processing object 7... Through-hole printed circuit board 8, 9... Electrode 10... Ion transfer electrode 11... Copper plating solution 12... Power supply for through-hole plating

Claims (3)

[Claims] (1) When processing a workpiece having micropores by a wet method, the workpiece is arranged so that liquid flows through the workpiece's micropores, and a pair of electrodes are placed on both sides of the workpiece. A wet electrolytic treatment device characterized by being equipped with. (2) The object to be processed is arranged so that the liquid flows through the micropores of the object, and the electrode for through-hole plating is connected to the micropore, and the object is electrically connected to the object. A wet electrolytic treatment apparatus, characterized in that a pair of electrodes are disposed on both sides of the object to be treated without contact, and through-hole plating is performed in the microholes by separately energizing the electrodes. (3) Claim 2 characterized in that the polarity of the electrode is changed at any time by energizing simultaneously or alternately with the energizing of the through-hole plating, or by further energizing.
The wet electrolytic treatment device described.