JP2525298B2 - Method for manufacturing printed wiring board - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a printed wiring board.

[0002]

2. Description of the Related Art Conventionally, a circuit pattern is formed by etching the copper foil of a copper clad laminate having a copper foil adhered to the surface of a resin substrate, and a resistor pattern is formed on the surface of the portion where the copper foil is removed. A printed wiring board having a printed structure is used. This resistor pattern is for directly sliding a metal slider on the resistor pattern to form a resistor.

Here, FIG. 7 is a diagram showing a manufacturing process of a printed wiring board of this type. 8 (a) to (c)
FIG. 8A is a side sectional view showing a state of the printed wiring board at steps 201, 205, and 206 of FIG. 7, respectively.

As shown in FIG. 7, first, the copper clad laminate 10 is cut into a desired shape (step 201). The state at this time is shown in FIG. As shown in the figure, the copper clad laminate 1
In No. 0, the adhesive layer 13 is applied on the hard resin substrate 11, and the copper foil 15 is attached thereon.

Next, as shown in FIG. 7, the surface of the copper foil 15 of the copper clad laminate 10 was polished, washed with water and dried (step 20).
2) After that, a pattern for etching is printed, dried (step 203), and etched (step 204). Then, the etching pattern is peeled off, washed with water and dried (step 205). The state at this time is shown in FIG.

Then, the resistor pattern 17 is printed on the surface a (see FIG. 8B) of the portion separated by the etching (step 206). The state at this time is shown in FIG.
Shown in

Then, as shown in FIG. 7, after the surface pretreatment (step 207), a solder resist is printed and dried (step 208) to manufacture a printed wiring board.

[0008]

By the way, in FIG. 8A, the lower surface of the copper foil 15 (that is, the surface to be adhered to the adhesive layer 13) is formed in order to improve the adhesiveness with the adhesive layer 13. , Is roughly trolled.

Therefore, in the state of FIG. 8B where the copper foil 15 is removed by etching, the exposed surface a of the adhesive layer 13 is also rough because the surface state of the copper foil 15 is transferred. It's rough.

Therefore, as shown in FIG. 8C, when the resistor pattern 17 is printed on the surface of the rough and rough adhesive layer 13, the resistor pattern 17 has an uneven thickness, which causes There is a problem in that the resistance value varies depending on the resistor pattern 17, and not only the total resistance value varies but also the resistance value change when the slider is brought into sliding contact with the resistor pattern 17 becomes non-linear.

The present invention has been made in view of the above points, and a printed wiring board capable of reducing variations in resistance value of a resistor pattern printed on a portion of a metal foil-clad laminate, which is removed by etching the metal foil. The present invention provides a method for manufacturing the same.

[0012]

In order to solve the above problems, the present invention provides an adhesive 13 on the surface of a hard resin substrate 11.
A method of manufacturing a printed wiring board, comprising: a step of etching a metal foil 15 adhered by the method to form a circuit pattern; and a step of printing a resistor pattern 17 on a surface of a portion removed by the etching. Immediately before the step of printing the resistor pattern 17, the adhesive layer 13 attached to the surface of the resin substrate 11 is attached to the rotary brush 19,
21 is provided.

Particularly in the present invention, the rotary brush 19,
The surface roughness of the adhesive layer 13 after polishing by 21 was set to 2 μm or less per 50 μm in length in the brushing direction of the rotary brushes 19 and 21.

[0014]

As described above, the surface of the adhesive layer 13 is polished by the rotating brushes 19 and 21 immediately before the step of printing the resistor pattern 17, so that the surface becomes smooth and the resistor pattern is formed on the surface of the adhesive layer 13. When 17 is printed, the thickness of the resistor pattern 17 becomes uniform. As a result, the resistance value of the resistor pattern 17 becomes uniform in each portion, and the variation can be reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a diagram showing a manufacturing process of a printed wiring board according to the present invention. 2 (a) to 2 (d)
Are the steps 101, 105, 106 and 10 of FIG. 1, respectively.
It is a figure which shows the state of the printed wiring board at the time of 7.

As shown in FIG. 1, first, the copper clad laminate 10 is cut into a desired shape (step 101). The state at this time is shown in FIG. As shown in the figure, the copper clad laminate 1
In No. 0, the adhesive layer 13 is applied on the hard resin substrate 11, and the copper foil 15 is attached thereon.

Next, as shown in FIG. 1, the copper clad laminate 10 is
The surface of the copper foil 15 was polished, washed with water and dried (Step 10
2) After that, a pattern for etching is printed, dried (step 103), and etched (step 104). Then, the etching pattern is peeled off, washed with water and dried (step 105). The state after step 105 is shown in FIG.

Then, in the present invention, as shown in FIG. 1, the entire surface of the copper clad laminate 10 is polished (step 1).
06).

As shown in FIG. 2 (c), this surface polishing is performed by polishing the surface of the copper-clad laminate 10 with the surface-polishing rotary brushes 19 and 21.
Specifically, the copper clad laminate 10 is placed under the rotating brushes 19 and 21.
By moving or reciprocating in the direction of the arrow (the rotating brushes 19 and 21 may be moved). The number of times of polishing with the rotating brushes 19 and 21 is
It may be once or more than once.

FIG. 3 is a side view showing the rotary brushes 19 and 21. As shown in FIGS. 2C and 3, the rotating brush 1
9 and 21 are so-called feather cloth brushes in which feather cloths 20 and 22 made of resin fibers are attached to the outer circumferences of cylindrical shafts 23 and 27. When polishing the surface of the copper-clad laminate 10 with the rotating brushes 19 and 21, the
As shown in (c), water drops 2 are applied to the rotary brushes 19 and 21.
6 is dropped.

By this surface polishing, the surface a of the exposed portion of the adhesive layer 13 [see FIG. 2 (b)] is polished and the irregularities thereof are smoothed.

Next, as shown in step 107 of FIG. 1, a resistor pattern 17 is printed on the surface a of the exposed portion of the adhesive layer 13. The state after printing is shown in FIG.

Then, as shown in step 108 of FIG. 1, after the surface pretreatment, a solder resist is printed and dried in step 109 to manufacture a printed wiring board.

As described above, since the exposed surface of the adhesive layer 13 is polished by the rotating brushes 19 and 21 immediately before the step of printing the resistor pattern 17, the surface of the adhesive layer 13 becomes smooth and the adhesive When the resistor pattern 17 is printed on the surface of the layer 13, the resistor pattern 17 has a uniform thickness, so that the resistance value of the resistor pattern 17 is uniform.

4 to 6 show the printed wiring board 30 manufactured by the manufacturing method according to the present invention, and FIG.
It is a figure which shows the specific example of comparative examination of the printed wiring board 30 'manufactured by the conventional manufacturing method shown in FIG.

First, FIG. 4 is a plan view showing the printed wiring boards 30 and 30 'used for the comparative examination. That is, as shown in the figure, a desired circuit pattern 25 (that is, the copper foil 15 left after etching) is formed by etching the copper foil of the copper-clad laminate, and in the case of the present invention, the entire surface is polished. In the case of the prior art, the resistor pattern 17 is printed on the surface of the portion where the copper foil has been removed without polishing, and the printed wiring board 30 according to the present invention and the conventional printed wiring board 30 'are respectively printed. I am configuring. The resistor pattern 17 of the printed wiring boards 30 and 30 'is a resistor pattern for a slide type variable resistor in which a metal slider is brought into sliding contact therewith to change its resistance value. The arrow shown in the figure indicates the direction of brushing by the rotating brush.

FIG. 5 shows these printed wiring boards 30, 3
It is a figure which shows the result of having measured the surface roughness of the adhesive agent layer 13 which is going to print the 0'resistor pattern 17, FIG. 1 (a) relates to this invention, FIG. It shows what it takes.

In the case of the printed wiring board 30 according to the present invention, since the surface is polished, the surface roughness is about 1 μm or less per length of 50 μm as shown in FIG. On the other hand, the conventional printed wiring board 3
In the case of 0, since the surface is not polished, the surface roughness is about 5 μm or less per 50 μm in length, as shown in FIG.

The surface roughness indicates the surface roughness in the brushing direction indicated by the arrow in FIG. Therefore, if the surface roughness is measured in a direction different from the brushing direction, the roughness will be different and will usually be higher.

FIG. 6A shows a printed wiring board 3 of the present invention.
It is a figure which shows the variation of the total resistance value of the resistor pattern 17 of 0, and FIG.6 (b) is a figure which shows the variation of the total resistance value of the resistor pattern 17 of the conventional printed wiring board 30 '.

As shown in the figure, the resistance value of the resistor pattern 17 of the printed wiring board 30 according to the present invention is almost uniform, whereas the resistance value of the resistor pattern 17 of the conventional printed wiring board 30 'is small. The values vary considerably.

As described above, in the case of the present invention, since the surface of the adhesive layer 13 is polished, the adhesive layer 13 is polished.
This is because the thickness of the resistor pattern 17 printed on the surface of is uniform in each part.

In order to significantly reduce the variation in the resistance value, the surface roughness of the adhesive layer 13 has a length of 50 in the brushing direction of the rotary brushes 19 and 21.
It is particularly preferable that the height of the irregularities per μm is 2 μm or less.

Although the copper foil is used as the metal foil forming the wiring pattern in the above embodiment, the present invention is not limited to this, and other metal foil such as aluminum foil may be used.

[0035]

As described above in detail, according to the method for manufacturing a printed wiring board of the present invention, when the resistor pattern is printed on the portion of the metal foil-clad laminate which is removed by etching the metal foil. Further, it has an excellent effect that variation in resistance value of the resistor pattern can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a manufacturing process of a printed wiring board according to the present invention.

2 (a) to 2 (d) are diagrams showing states of the printed wiring board at steps 101, 105, 106, and 107 of FIG. 1, respectively.

FIG. 3 is a side view showing rotating brushes 19 and 21.

FIG. 4 is a plan view showing printed wiring boards 30 and 30 ′ used for comparative examination of the present invention and a conventional example.

FIG. 5 is a diagram showing the results of measuring the surface roughness of the adhesive layer 13 on which the resistor patterns 17 of the printed wiring boards 30 and 30 'are printed, and FIG. 5 (a) is a printed wiring board of the present invention. The figure which shows the measurement result of the board | substrate 30, and the figure (b) is a figure which shows the measurement result of the conventional printed wiring board 30 '.

6 (a) is a diagram showing variations in the total resistance value of the resistor pattern 17 of the printed wiring board 30 of the present invention, and FIG. 6 (b) is a resistor of the conventional printed wiring board 30 '. FIG. 7 is a diagram showing variations in the total resistance value of the pattern 17.

FIG. 7 is a diagram showing a manufacturing process of a conventional printed wiring board.

8A to 8C are diagrams showing states of the printed wiring board at the steps 201, 205, and 206 of FIG. 7, respectively.

[Explanation of symbols]

 11 Resin Substrate 13 Adhesive Layer 15 Copper Foil 17 Resistor Pattern 19, 21 Rotating Brush 25 Circuit Pattern 30 Printed Wiring Board

Claims (2)

(57) [Claims] 1. A step of forming a circuit pattern by etching a metal foil adhered to the surface of a hard resin substrate with an adhesive, and a step of printing a resistor pattern on the surface of the portion removed by the etching. A method of manufacturing a printed wiring board comprising: a step of polishing a layer of adhesive adhered to the surface of the resin substrate with a rotating brush immediately before the step of printing the resistor pattern. Method for manufacturing printed wiring board. 2. The surface roughness of the adhesive layer after polishing with the rotating brush is such that the unevenness height is 2 μm or less per 50 μm in length in the brushing direction of the rotating brush. Wiring board manufacturing method.