JPS5989783A - Electroplating device - Google Patents

Abstract

PURPOSE:To enable plating operation at a high speed by superposing mask plates formed with liquid passage holes in the positions corresponding to the through-holes of a substrate for forming through-holes on the substrate having said holes and forming a plating layer on the conductive layer on the internal circumferential surface of each hole. CONSTITUTION:A cover 2 is opened and a substrate 8 is placed on the 1st mask plate 4, then the cover 2 is closed and the substrate 8 is sandwiched between the 1st and 2nd masks 4, 6. The through-holes 9 of the substrate 8 and the liquid passage holes 11 of the plates 4, 6 coincide with each other in this stage. A high pressure pump 14 is thereafter started to fill the plating soln. 13 in a plating soln. tank 12 in a plating cell 1. The soln. 13 passes through a perforated plate 16 and flows toward the upper side approximately constantly over the entire region thus flowing at a high velocity in the holes 11 of the plates 4, 6 and the holes 9 of the substrate 8. A power source device 19 for plating is turned on in this stage to inpress a voltage between an anode 17 and the conductive layer 10 of the substrate 8, thereby forming a plating layer 20 on the inside circumferential surface and land part of each hole 9 which are not covered by the plates 4, 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an 11-ton plating device for electroplating the inner peripheral surface of a through hole for forming a through hole.

Conventionally, for example, through-holes have been formed in a double-sided printed circuit board in the following manner. That is, first, a conductive layer is formed by chemical copper plating on the entire surface of a printed circuit board in which a hole for forming a through hole is formed, and a metal resist is printed on both sides of the printed circuit board, leaving a land area around the hole. The backside printed circuit board is immersed in the plating solution and swung, and a predetermined voltage is applied between the conductive layer and the anode in the plating solution, thereby removing the portion not covered with the plating resist, that is, the inner periphery of the through hole. An electroplated layer was formed on the surface and land portions.

However, in the above method, it is difficult for the plating solution to flow through the through-holes, so when the current density is increased to perform high-speed plating, metal ions are depleted in the plating solution near the through-holes. As a result, a large amount of hydrogen gas is generated due to the discharge of hydrogen ions, leading to a decrease in current efficiency and abnormal precipitation that makes the plating locally non-uniform. Climbing or cracking may occur. However, even if the plating solution is allowed to flow through the through-hole, relatively weak plating resist may rise from the substrate due to abnormal precipitation caused by the turbulence generated in the vicinity of the through-hole, which is undesirable. For this reason, in the past, it was not possible to sufficiently increase the current density and, furthermore, it was not possible to perform high-speed plating work.

The present invention has been made in view of the above circumstances, and its objects are to provide a substrate having a through hole for forming a through hole, and a mask having a liquid passage hole formed in the substrate at a position corresponding to the IIJ distribution hole. By having a configuration in which plating is applied to the conductive layer formed on the inner circumferential surface of the through hole while flowing the plating solution into the through hole, the current density can be increased and high speed plating work can be achieved. The purpose of the present invention is to provide a peek plating device capable of performing plating.

The first example of the present invention will be explained below with reference to FIGS. 1 to 3. 1 is plated t1, which is a container-shaped tray 2
It is configured so that it can be opened and closed. Reference numeral 3 denotes a lower frame provided at the periphery of the opening of the plating tank 1, and a T-shaped support step 3a is formed on the inner circumferential side of the lower frame, and the first mask plate 4 is fitted into this support step 3aK in a liquid-tight manner. Fixed. Reference numeral 5 designates an upper frame provided at the periphery of the opening of the lid 2, which also has a stepped portion 5at similar to the lower frame 5.
A second mask plate 6 is liquid-tightly fitted and fixed to this crotch portion 5a. 7 is the first and second mask plate 4.6
Rubber sheets for sealing are attached to the upper and lower surfaces of the holder, and are made of, for example, hard rubber with a hardness of 600 to 150°. Reference numeral 8 denotes a board made of a double-sided copper-clad laminate in which copper foil 8b is adhered to both sides of a board 8a made of a glass epoxy board. It is detachably arranged so as to be sandwiched between the mask plates 4 and 6. Then, a through hole 9 for forming a through hole is bored at a predetermined position in this substrate 8 using, for example, a No. A layer 10 is formed. In addition, the first and second mask plates 4 and 6 described in ml
is made of a glass epoxy plate made of the same material as the base material of the substrate 8, and has a through hole at a position corresponding to each through hole 9 of the substrate 8 with the same diameter as the through hole 9 or slightly enlarged to form a land. A liquid hole 11 is formed. These liquid passage holes 11 were drilled using an NC drilling machine in the same way as the through holes 9, and they were drilled using NO tape that was the same as that used for drilling the through holes 9 or with only the hole diameter changed. The formation position of the hole 11 is made to precisely match that of the through hole 9. Reference numeral 12 denotes a plating solution tank that stores a plating solution 16. This plating solution 16 is supplied into the plating tank 1 by a high-pressure pump 14, and passes through the solution hole 11 of the mask plate 4.6 and the through hole 9 of the substrate 8. and reaches inside the lid 2, and from inside this lid 2 a circulation pipe 15
It returns to the plating solution tank 12 via the plating solution tank 12.

Reference numeral 16 denotes a titanium porous plate disposed within the plating side 1, which is placed near the first mask plate 4 so as to face substantially parallel to the mask plate 4. Melt. 17
1 is an anode disposed at the bottom of the plating bath 1, and 18 is a cathode side lead wire provided in contact with the conductive M10 of the substrate 8. These anode 17 and lead wire 18 are connected to a plating power supply 19.
are connected.

Next, the operation of the above configuration will be explained. First, open the short 2 and place the substrate 8 on the mask plate 4 of @1, close the lid 2, and sandwich the substrate 8 between both the mask plates 4 and 6 of sl and jg2. do. In this state, the through hole 9 of the substrate 8 and the
and the liquid passage holes 11 of each second mask plate 4.6 coincide with each other. After that, when the high-pressure pump 14 is started, the plating solution 13 in the plating solution tank 12 fills the plating tank 1, and in the process of passing through the perforated plate 16, the plating solution 13 flows upward while keeping the momentum substantially constant over the entire area. When the high speed 19 is turned on and a predetermined voltage is applied between the anode 17 and the conductive layer 10 of the substrate 8, During the process in which the plating solution flows through the through holes 9, the first and second mask plates 4 of the four electrical layers 10 of the substrate 8
．． 6, that is, the inner peripheral surface of the through hole 9 and the land portion, the T stopper lid 2 is opened and the substrate 8t is taken out.

According to the above embodiment, since new plating solution 13 can be constantly supplied at high speed to the part where the plating layer 20 is to be formed, the concentration of plating solution C metal ions near the plating part decreases, unlike the conventional method. This makes it possible to prevent hydrogen gas from being generated, thereby making it possible to obtain a sufficiently high current density and perform plating at high speed. Incidentally, with conventional plating equipment, the rounding required to form a copper plating layer of approximately 50 μm in the through hole 9 for forming a null hole requires a maximum of approximately 1.5 to 2.5 μm.
It used to take about 40 to 60 minutes at a current density of A4, but in this embodiment, the plating solution 13' flowing through the through hole 9
When the current density is set to about 5 to 30 m/n+in, the current density can be set to about 10 to 50 m, and the time required to form a steel plating layer of the same thickness as the conventional one is about 2 to 50 m.
It took me 6 minutes. In addition, since the first and second mask plates 4.6 are sufficiently strong compared to conventional printed metkinocyst layers, even if the plating solution 15 is passed through the through holes 9 at a high speed, the through holes 9 can be closed. The turbulence generated on the inlet and outlet sides will not break the mask plate 4.degree. 6, nor will it float up from the substrate 8. Moreover, since the first and second mask plates 4.6 can be used repeatedly, when plating a large number of substrates 8 of the same type, compared to the conventional method in which plating resist must be printed one by one for each substrate. This will greatly reduce plating costs.

In addition, since the areas to be electroplated are the inner periphery of the through-hole and the land area for through-hole formation, the plated area is extremely small and has the same shape, making the plating thickness distribution extremely uniform. We refuse to make efforts to improve quality.

Furthermore, especially if the perforated plate 16 is arranged in the plating bath 1 near the first mask plate 4 as in this example,
Even under the circumstances that the high-pressure pump 14 discharges the plating solution 15 into the plating tank 1 with a strong force, causing turbulence in the plating tank 1, when the plating solution 13 passes through the perforated plate 16, Since the flow becomes a laminar flow that flows straight upward and the momentum of the flow is made uniform over the entire area of the perforated plate 16,
The plating solution 13 flows as a laminar flow inside the through hole 9 without any disturbance, and the speed of the plating plate 13 flowing through it is also made uniform over the entire area of the substrate 8, and as a result, the layer thickness of the plating layer 20 is reduced to 1.
Even within a single through hole 9 or for each through hole 9, uniformity can be achieved as much as possible. Further, in this practical example, the perforated plate 16 is simply disposed near and facing the first mask plate 4;
A positive potential lower than 7 may be applied. In this way, the plating layer 20 can be formed with a more substantially uniform thickness for the through holes 9 formed at any position on the substrate 8. This is because when no positive potential is applied to the porous plate 16, the distribution of electric lines of force between the substrate 8 and the anode 17 tends to become denser toward the periphery of the substrate 8, as described above. It is believed that by applying a positive voltage lower than that to the anode to the porous plate 16, it is possible to make the distribution of electric lines of force on the surface of the substrate 8 as uniform as possible between the central part and the peripheral part.

Moreover, in this practical example, in particular, the first and second mask plates 4,
Since the material of No. 6 was made the same as that of the base material of substrate B,
The expansion and contraction rates of the second mask plate 4.6 and the substrate 8 due to temperature changes or moisture absorption are made equal. Thereby, it is possible to prevent misalignment between the through hole 9 and the liquid passage hole 11 due to expansion and contraction of the substrate 8 and the mask plate 4°6.

4 and 5 show a second leprosy example of the present invention,
The difference from the above embodiment is that a flexible (so-called) V-kimple printed circuit board 20 is used as the substrate, and the plating bath 1 is
The long strip-shaped flexible printed circuit board 20 is wound around a drum 21 provided on one side, and is passed between the first and second mask plates 4 and 6 of the plating tank 1 on the other side of the plating tank 1. It is arranged so that it can be wound up by a winding drum 22 provided on one side. This flexible printed circuit board 2
0, 9 groups of through holes for forming a large number of through holes are formed in advance, and these 9 groups of through holes form the first and second mask plates 4.0.
The flexible printed circuit board 20 is intermittently wound around the winding drum 22 so as to correspond to the 11 groups of liquid passage holes formed in 6.
The high voltage bomb 014 and the plating power supply device 19 are operated in accordance with the timing.

In addition, in each of the above embodiments, each of the first and second mask plates 4.6
A rubber sheet 7 for sealing is pasted on each of the rubber sheets, but these may be provided as necessary.

In addition, the present invention is not limited to the embodiments described above and shown in the drawings. For example, the lid 2 of the plating 11 is provided with a detection electrode for detecting the ejection of the plating solution, and this detection electrode is connected to the substrate 8, 2 The plating power supply device 19 may be activated at the same time as the flow through the through-hole 9 is detected, and various modifications can be made without departing from the gist of the invention.

As described above, the present invention includes a substrate for growing through holes for forming through holes, and a mask plate that is attached to this substrate and has liquid passage holes formed at positions corresponding to the through holes, and The feature is that plating is performed on the conductive layer formed on the inner circumferential surface of the through hole while the plating liquid is flowing inside the hole.As a result, new plating liquid is constantly supplied into the through hole. This has the excellent effect of increasing the blood flow density, which in turn allows plating to be performed at high speed, and further reduces plating costs by repeatedly using the mask plate.

[Brief explanation of the drawing]

1 to 6 show a first embodiment of the present invention. FIG. 1 is an overall vertical sectional view, FIG. 2 is an enlarged vertical sectional view of the substrate and mask plate, and FIG. 3 shows the state after plating. 2, 4 and 5 show a second example of the present invention, FIG. 4 is a view corresponding to FIG. 1, and FIG. 5 is a partial plan view of a flexible printed circuit board. In the figure, 4.6 is a first and second mask plate, 8.degree. 20 is a substrate, 9 is a through hole, 10 is a conductive layer, 11 is a liquid passage hole, 13 is a plating solution, and 16 is a porous plate. Applicant: Yamada Plating Industry Co., Ltd. 8P! 11mg No. 2 Amendment to figure procedure December 20, 1980 Mr. Commissioner of the Japan Patent Office■, Small case indication patent application No. 199426 No. 2, Title of invention Electroplating device 3, person making the amendment voluntarily 6 Subject of amendment Detailed description of the invention in the specification. 7. Contents of the amendment (1) The sentence “flowing through the perforated plate 16” written from line 12 to line 16 K on page 8 of the specification is deleted and the text is inserted here. Add the following text. "The perforated plate 16 can prevent the local discharge pressure of the high-pressure pump 14 from reaching the substrate 8" (2), page 9, No. 2
Add the following sentence next to "I can do it." written on the 0th line. ``In addition, whether the diameter of the through hole 9 or the liquid passage hole 11 is relatively large,
If the positional accuracy of the through hole 10 is not required, it is not necessarily necessary to use the same material. ” (3) Delete the words “according to the timing” from lines 14 to 15 on page 10. (4) The phrase "may be done, etc." written on page 11, line 5 of the same is deleted and the following sentence is added here. Alternatively, a voltage may be applied before the plating solution passes through, so that when the plating solution flows, a current flows from the k. It may also be placed inside the lid 2, etc.

Claims (1)

[Claims] 1. A mask plate having a substrate having a through hole for forming a through hole, and a mask plate having a liquid passage hole formed in a position corresponding to the through hole, which is applied to the substrate, An electroplating device characterized in that plating is performed on the conductive layer formed on the inner circumferential surface of the through hole while a plating solution is passed through the hole. 2. The electroplating apparatus according to claim 1, wherein a perforated plate is provided near the plating solution inflow side of the substrate and facing the substrate.