JP2001254197A - Method of manufacturing printed circuit board and electroplating device used in its electroplating stage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing printed circuit board by which the deposition characteristics in electrolytic pattern plating when the wiring pattern has roughness and fineness is made equal to or better than that in panel plating, a printed circuit board having a pattern having great roughness and fineness is manufactured by a pattern process, and a fine pattern is easily formed, and its electroplating device used in the electroplating. SOLUTION: A resist pattern to form a printed wiring pattern is formed on a printed circuit board 3 with conductivity imparted to the surface and the inner wall face of a through-hole, then an electroplating is deposited on the printed wiring pattern by a carrier-conveying electroplating device, using a pulse current consisting of a positive current and negative current to manufacture the printed circuit board, and the carrier-conveying electroplating device used in the plating is provided with a pulse current supply means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a printed wiring board for manufacturing a printed wiring board such as a double-sided printed wiring board or a multilayer printed wiring board, and a carrier transport type electrolytic plating used in the electrolytic plating step of the method. It concerns the device.

[0002]

2. Description of the Related Art Conventionally, three methods, that is, a pattern method, a panel pattern method, and a panel tenting method, which will be described below, are typically used as a method of manufacturing a printed wiring board. (1) The pattern method is as follows: 1A: a step of drilling a double-sided board or a multilayer board 1B: a step of imparting conductivity to the drilled inner wall and surface of the double-sided board or the multilayer board by electroless copper plating or the like 1C: double-sided board Step of forming a resist pattern for forming a printed wiring pattern on a board or multilayer board 1D: Step of performing electrolytic copper plating / solder plating using this resist pattern as a mask 1E: Step of removing resist pattern 1F: Solder plating This is a method comprising a step of removing exposed copper as an etching resist using an etching solution.

(2) The panel pattern method is as follows: 2A: a step of perforating a double-sided board or a multilayer board 2B: imparting conductivity to the perforated inner wall and surface of the double-sided board or the multilayer board by electroless copper plating or the like. Step 2C: Step of performing panel copper plating 2D: Step of forming a resist pattern for forming a printed wiring pattern on a double-sided board or multilayer board 2E: Step of performing electrolytic copper plating / solder plating using this resist pattern as a mask 2F: Step of stripping resist pattern 2G: Step of removing exposed copper using an etching solution using solder plating as an etching resist.

(3) The panel tenting method is as follows: 3A: a step of making a hole in a double-sided board or a multilayer board. 3B: A conductive property is applied to the holed inner wall and surface of the double-sided board or the multilayer board by electroless copper plating or the like. Step of applying 3C: Step of performing copper plating on panel 3D: Step of forming a resist pattern for forming a printed wiring pattern on a double-sided board or a multilayer board 3E: Using this resist pattern as an etching resist, removing exposed copper with an etching solution 3F: removing the resist pattern.

[0005] Among these methods, in the case of the pattern method (1), electrolytic copper plating of about 30 µm is formed only on a printed wiring pattern formed on a base copper foil (18 µm). Since the thickness of the unnecessary portion, that is, the thickness of copper removed by etching can be reduced and the size of side etching at the time of etching can be reduced, a fine pattern can be formed in the case of a uniform wiring pattern. Having. However, when the wiring pattern is dense and dense, current concentrates on the sparse part, so that the variation in plating thickness on the pattern becomes large, which causes a problem in pattern formation, and also causes a problem in pattern formation. There was a problem that a short circuit occurred between them and a problem in forming a solder resist.

On the other hand, in the case of the panel pattern method and the panel tenting method of (2) and (3), since the panel copper plating of about 20 to 30 μm is performed as the primary copper, the plating thickness in the case of the dense / dense pattern is obtained. Can solve the problem of variation in the thickness, but on the other hand, the copper thickness of the unnecessary portion is 3
The thickness is as large as 8 to 48 μm (base copper foil 18 μm + panel copper plating thickness 20 to 30 μm), and therefore, the size of side etching at the time of etching is also large, and there is a problem that it is difficult to form a fine pattern. Was. Also, as a problem of the apparatus used in the plating step, in the case of a carrier transport type electrolytic plating apparatus, the current output from the rectifier is supplied from the end of the carrier bar through the carrier bar receiver (= power supply block). Therefore, the longer the length of the carrier bar, the greater the effect of the voltage drop in the length direction. The potential is higher at the end of the carrier bar and lower at the center. For this reason, there has been a problem that the plating thickness varies between the printed wiring boards racked by the same carrier, and the product quality becomes non-uniform.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to address the above-mentioned problems, and the first object of the present invention is to reduce the plating thickness in electrolytic pattern plating when the wiring patterns are sparse and dense. It is an object of the present invention to provide a method of manufacturing a printed wiring board which can make deposition characteristics such as variation, throwing power, and gloss appearance equal to or more than those obtained by panel plating. Another object of the present invention is to provide a method of manufacturing a printed wiring board that enables a printed wiring board having a large pattern of large and small densities to be manufactured by a pattern method and that can easily form a fine pattern. A further object of the present invention is a carrier transport type electrolytic plating apparatus used in the electrolytic plating step of the above-described method for manufacturing a printed wiring board, wherein the plating thickness of a plurality of printed wiring boards racked by the same carrier bar is reduced. An object of the present invention is to provide an electrolytic plating apparatus capable of eliminating variations.

[0008]

In order to solve the above-mentioned problems, a method of manufacturing a printed wiring board according to the present invention comprises a method of forming a printed wiring pattern on a printed wiring board having a surface and an inner wall surface provided with conductivity. After passing through the process of forming a resist pattern for forming, electrolytic plating is deposited on the printed wiring pattern and through holes using a pulse current consisting of a positive current and a negative current by a carrier transport type electrolytic plating device. By properly setting the current value ratio and the current time ratio of the pulse current composed of the positive current and the negative current, electrolytic plating having characteristics equal to or higher than that obtained by panel plating can be performed only on the printed wiring pattern. The plating thickness between multiple printed wiring boards that can be deposited and racked on the same carrier bar Suppressing the variability, it can allow for producing a printed wiring board by pattern method having a large pattern of density.

Further, the method of manufacturing a printed wiring board according to the present invention is the same as the above-described method of manufacturing a printed wiring board,
In the electrolytic plating step, a potential in a longitudinal direction of a carrier bar racking the printed wiring board is substantially equalized, and a plurality of the printed wiring boards racked by the carrier bar are energized substantially uniformly to perform electrolytic plating. It is characterized in that it is deposited.Electroplating can be deposited by energizing a plurality of printed wiring boards racked by a carrier bar substantially uniformly, thereby eliminating variations in plating thickness on the printed wiring board. be able to.

Further, according to the present invention, there is provided a method of manufacturing a printed wiring board, comprising the steps of:
In the electrolytic plating step, the ratio of the negative current value to the positive current value in the pulse current is set to 2. O or less, wherein the ratio of the positive current time to the reverse current time is set to 20 to 30: 1, and electrolytic plating having a glossy appearance is deposited, and the ratio of the positive current to the negative current in the pulse current is And the ratio of the current time to 2. Below O and 20
By setting the ratio to ３０30: 1, a uniform electrodeposition property and a decrease in throwing power can be suppressed, and the plating surface can be brought into a gloss state equivalent to that obtained by panel plating.

Further, in the method for manufacturing a printed wiring board according to the present invention, in the above-described method for manufacturing a printed wiring board, in the electrolytic plating step, after the electrolytic plating is performed by using the pulse current, the method is continuously performed. It is characterized by adding plating by DC current, and after electroplating using pulsed current, the plating surface with DC current is thinly added continuously, so that the plating surface is as bright as that by panel plating. State.

On the other hand, an electrolytic plating apparatus according to the present invention is an electrolytic plating apparatus of a carrier transport type used in the electrolytic plating step of the above-described method for manufacturing a printed wiring board, wherein a printed wiring board racked by a carrier bar is provided. A pulse current supply means for supplying a pulse current composed of a positive current and a negative current, wherein a resist pattern is formed, and a printed wiring pattern and a through-hole of a printed wiring board racked by a carrier bar are provided. Electrolytic plating can be deposited by supplying a pulse current consisting of a positive current and a negative current to the hole.

[0013] The electroplating apparatus according to the present invention is the electroplating apparatus as described above, wherein the pulse current feeding means feeds a pulse current output from a rectifier to a printed wiring board racked by a carrier bar. Therefore, the anode cable and the cathode cable connected between the rectifier and the carrier bar and the anode bus bar have a twisted wiring structure, and the anode cable and the cathode cable have the same length, With such a configuration, it is possible to perform electrolytic plating while uniformly supplying current to a plurality of printed wiring boards racked by a carrier bar without smoothing (smoothing) the pulse current output from the rectifier.

Further, the electrolytic plating apparatus according to the present invention is the electrolytic plating apparatus described above, wherein the pulse current supply means supplies the pulse current output from the rectifier to the printed wiring board racked by the carrier bar. Therefore, a power supply block is provided at a plurality of positions where the carrier bar is equally divided in the length direction to supply power. With this configuration, the potential over the entire length direction of the carrier bar is reduced. Electroplating can be performed while supplying a substantially uniform pulse current to the printed wiring board irrespective of the positions of the plurality of racked printed wiring boards.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a longitudinal sectional view showing the structure of a carrier transport type electroplating apparatus used in the first embodiment of the present invention, FIG. 2 is a plan view showing its wiring structure, and FIG.
(A) shows a pulse current feeding position to the carrier bar of the electrolytic plating apparatus, (B) shows a pulse current waveform in the length direction thereof, and (B) shows a ratio of a current value of the pulse current to a current time ( C), FIG. 4 is a longitudinal sectional view showing the structure of a carrier transport type electrolytic plating apparatus used in the second embodiment of the present invention, FIG. 5 is a plan view showing the wiring structure thereof, and FIG. 6 is a carrier of the electrolytic plating apparatus. FIG. 3A is a diagram showing a pulse current supply position to a bar, FIG. 3B is a diagram showing a pulse current waveform in the length direction thereof, and FIG. 3C is a diagram showing a ratio of a current value of the pulse current to a current time.

An object of the present invention is to make it possible to manufacture a printed wiring board having a large pattern with high and low density by a pattern method and to easily form a fine pattern. After drilling, through a process of forming a resist pattern for forming a printed wiring pattern on a printed wiring board with conductivity imparted to the drilled inner wall and surface by electroless copper plating etc., the carrier transport method In the step of electrolytic plating using the electrolytic plating apparatus described above, the electrolytic plating is deposited on the wiring patterns and through holes of the printed wiring board using a pulse current composed of a positive current and a negative current. In order to maximize the effect of the electrolytic plating by the pulse current, a plurality of printed wirings racked by a carrier bar are used without smoothing (smoothing) the pulse current waveform output from the rectifier in the electrolytic plating process. It is important that the plate be evenly energized.

For this reason, in a carrier transport type electroplating apparatus, a wiring structure from a rectifier to a carrier bar and an anode bus bar and a uniform waveform on a plurality of printed wiring boards racked in the length direction with respect to the carrier bar. A configuration for supplying the current is required. Figures 1 and 2
In the drawing, reference numeral 1 denotes a plating tank filled with a plating solution 2, which is immersed in a state in which the printed wiring board 3 is racked through a clip 5 on a carrier bar 4. It is supposed to be. The carrier bar 4 is supported by a carrier bar receiver 7 via a power supply block 6, and the carrier bar 4 is energized by contact between the power supply block 6 and the carrier bar receiver 7. An anode bus bar 8 is provided on both sides of the carrier bar 4 in parallel.

The carrier bar 4 and the anode bus bar 8
A cathode cable 10 and an anode cable 11 for supplying a pulse current composed of a positive current and a negative current output from the rectifier 9 are wired and connected via a carrier bar receiver 7. The cathode cable 10 and the anode cable 11 are connected to the rectifier 9
In order to prevent rounding (smoothing) due to reactance of the pulse current waveform output from the circuit board and to evenly energize the plurality of printed wiring boards 3 racked by the carrier bar 4, twist as shown in S part of FIG. Wiring structure
Both ends of the carrier bar 4 and the anode bus bar 8 are connected with an equal length.

According to this embodiment, the printed wiring board 3 having conductivity provided on the surface and the inner wall surface of the through hole is provided with:
After a step of forming a resist pattern for forming a printed wiring pattern, in a step of electroplating using a carrier transport type electroplating apparatus, a wiring pattern and a through hole of the printed wiring board 3 are added to FIG.
As shown in (A), the carrier bar 4 and the anode bus bar 8
And a pulse current composed of a positive current and a negative current having an output waveform as shown in FIG. 3 (B) and a current value ratio and a current time ratio appropriately set as shown in FIG. 3 (C). By energizing, it is possible to deposit electrolytic plating having characteristics equal to or higher than that of panel plating only on the printed wiring pattern.

Then, the electrolytic plating is deposited using a pulse current, and the plurality of printed wiring boards 3 racked in the longitudinal direction of the carrier bar 4 are evenly energized, so that the printing within the same carrier bar 4 is performed. Since it is possible to suppress the variation in plating thickness between the wiring boards 3 and to perform uniform plating, it is possible to manufacture the printed wiring board 3 having a large density pattern by a pattern method, and it is easy to form a fine pattern. Can be

When electrolytic plating is performed using a pulse current composed of a positive current and a negative current, the negative current has a plating peeling action, so that the ratio of the negative current value to the positive current value is large and the negative current time is long. Thus, fine irregularities occur on the plating surface, and the deposited plating becomes dull. Therefore,
For the purpose of facilitating inspection with a reflection type optical inspection machine, or to obtain a glossy appearance due to appearance problems, in order to make the electrolytic plating surface to be deposited the same glossy state as that by panel plating, The following two methods can be used.

(1) The ratio of the negative current value to the positive current value shown in FIG. 3C is 2.0 or less, and the ratio of the positive current time to the reverse current time is 20 to 30: 1. However, as the ratio of the negative current value decreases and the ratio of the positive current time to the reverse current time increases, the uniform electrodeposition and the throwing power decrease. 2.
0, the ratio of the positive current time to the reverse current time is preferably 20: 1. (2) The ratio of the negative current value to the positive current value in the electrolytic plating process is 2.5 in order to obtain a glossy appearance while ensuring characteristics that the circuit thickness is constant irrespective of the density of the pattern, with a throwing power of 100% or more. After electroplating using a pulse current of ~ 3.5, plating by direct current is added thinly continuously.

Thus, according to the above-described embodiment, it is possible to deposit electrolytic plating having characteristics equal to or higher than those obtained by panel plating, that is, variations in plating thickness, throwing power, and glossy appearance only on a printed wiring pattern. Since it is possible to form a fine pattern by etching, it is possible to reduce the variation in plating thickness between printed wiring boards, while taking advantage of the pattern method,
The problem can be solved and a product of stable quality can be manufactured.

The method of supplying power to the plurality of printed wiring boards 3 racked by the carrier bar 4 is affected by the voltage drop when power is supplied from the ends of the carrier bar 4 and the anode bus bar 8, and FIG. ), The potential is high at the ends of the carrier bar 4 and the anode bus bar 8, and the potential is low at the center. Therefore, compared to the current waveform output from the rectifier 9, the carrier is racked at the end of the carrier bar 4. As shown in FIG. 3B, the waveform of the current transmitted to the printed wiring board 3 is distorted in a direction in which the positive current and the reverse current increase, and the positive current and the reverse current weaken toward the center of the carrier bar 4. The waveform will be disturbed.

Therefore, the pulse current from the rectifier 9 is not directly applied to the ends of the carrier bar 4 and the anode bus bar 8,
As shown in FIG. 6A, power is supplied by providing a power supply block 12 made of copper, titanium, or the like at a plurality of positions where the carrier bar 4 is equally divided in the length direction as in the second embodiment shown in FIG. Since the potential in the length direction of the carrier bar 4 can be made substantially uniform over the entire length, regardless of the racking positions of the plurality of printed wiring boards 3 racked by the carrier bar 4, as shown in FIG. The pulse current waveform supplied to the printed wiring board 3 can be made uniform. In this case, as shown in FIG. 4, the carrier bar 4 is provided with an insulating material 13 interposed between the power supply block 6 and the end of the carrier bar 4 in order to cut off the current supply from the end of the carrier bar 4. .

According to the second embodiment as well, the effect of the pulse current can be maximized as described above, and the pulse current waveform output from the rectifier 9 in the electrolytic plating step is smoothed (smoothed). It is possible to carry out electrolytic plating with a uniform plating without causing variations in plating thickness by uniformly supplying power to the plurality of printed wiring boards 3 racked by the carrier bar 4. The power supply block 12 is provided at a plurality of positions where the carrier bar 4 is equally divided in the length direction to supply power.
Should be 2 or more, and the larger the value, the more uniform the potential in the length direction.

[0027]

As described above in detail, according to the method for manufacturing a printed wiring board according to the present invention and the electrolytic plating apparatus used in the electrolytic plating step, a pulse current consisting of a positive current and a negative current is used. Electrolytic plating having characteristics equal to or higher than panel plating can be deposited only on a printed wiring pattern. Therefore, it is easy to form a fine pattern by etching, to eliminate the disadvantages while taking advantage of the patterning method, to reduce the variation in plating thickness between printed wiring boards, and to stabilize product quality. Become like

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration of a carrier transport type electrolytic plating apparatus used in a first embodiment of the present invention.

FIG. 2 is a plan view showing a wiring structure of the electroplating apparatus according to the first embodiment of the present invention.

FIG. 3A is a diagram showing a pulse current supply position to a carrier bar in an electrolytic plating apparatus according to an embodiment of the present invention, FIG. 3B is a diagram showing a pulse current waveform in a length direction thereof, and FIG. FIG. 9C is a diagram showing a ratio between the current and the current time.

FIG. 4 is a longitudinal sectional view illustrating a configuration of a carrier transport type electroplating apparatus used in a second embodiment of the present invention.

FIG. 5 is a plan view showing a wiring structure of an electrolytic plating apparatus according to a second embodiment of the present invention.

FIG. 6A is a diagram showing a pulse current supply position to a carrier bar in the electrolytic plating apparatus according to the embodiment of the present invention, FIG. 6B is a diagram showing a pulse current waveform in the length direction thereof, and FIG. FIG. 9C is a diagram showing a ratio between the current and the current time.

[Description of Signs] 1 ... Plating tank, 3 ... Printed wiring board, 4 ... Carrier bar, 6, 12 ... Power supply block, 7 ... Carrier bar receiver,
8 ... Anode busbar, 9 ... Rectifier, 10 ... Cathode cable,
11… Anode cable

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 3/42 620 H05K 3/42 620B F term (Reference) 4K024 AB01 AB08 BB11 BC01 CA08 CB04 CB05 EA07 FA07 FA08 GA02 GA16 5E317 AA24 BB01 BB11 CC32 CC33 CC42 CC44 CD15 GG01 5E343 AA07 BB24 DD46 FF16 FF18 GG06

Claims (7)

[Claims] 1. A process for forming a resist pattern for forming a printed wiring pattern on a printed wiring board having conductivity imparted to the surface and the inner wall surface of a through hole, and then performing a printed wiring by a carrier transport type electrolytic plating apparatus. A method for manufacturing a printed wiring board, wherein electrolytic plating is deposited on a pattern and a through hole using a pulse current composed of a positive current and a negative current. 2. In the electroplating step, a potential in a longitudinal direction of a carrier bar racking the printed wiring board is substantially equalized, and a plurality of printed wiring boards racked by the carrier bar are substantially uniformly energized. The method for producing a printed wiring board according to claim 1, wherein electrolytic plating is performed by depositing. 3. In the electroplating step, a ratio of a negative current value to a positive current value in the pulse current is set to 2. O or less, the ratio of the positive current time to the reverse current time is 20 to 3
The method for producing a printed wiring board according to claim 1, wherein electrolytic plating having a glossy appearance is deposited at a ratio of 0: 1. 4. The printed wiring according to claim 1, wherein, in the electroplating step, after electroplating is performed using the pulse current, plating by direct current is continuously added. Plate manufacturing method. 5. A carrier transport type electroplating apparatus used in an electroplating step of the method for manufacturing a printed wiring board according to claim 1, wherein the printed wiring board racked by a carrier bar comprises: An electrolytic plating apparatus comprising: a pulse current supply unit that supplies a pulse current including a positive current and a negative current. 6. An anode cable connected between the rectifier and the carrier bar and the anode busbar to supply the pulse current output from the rectifier to the printed wiring board racked by the carrier bar, as the pulse current supply means. The electrolytic plating apparatus according to claim 5, wherein the cathode cable has a twisted wiring structure, and the anode cable and the cathode cable have the same length. 7. A power supply means for supplying a pulse current output from a rectifier to a plurality of positions equally divided in a length direction of the carrier bar in order to supply a pulse current output from a rectifier to a printed wiring board racked by the carrier bar. 6. A power supply system comprising a block.
An electroplating apparatus according to item 1.