JP3082364B2 - Printed circuit board manufacturing method - 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 circuit board, and more particularly to a method for printing a mark formed on a solder resist.

[0002]

2. Description of the Related Art As shown in FIG. 12, a printed circuit board has a conductor pattern 8, a solder resist 7, and a mark 6 printed on the solder resist 7 provided on the surface of an insulating substrate 9. That is, various conductive patterns 8 are formed on the surface of the insulating substrate 9 in the printed circuit board 5. The conductor pattern 8 includes a wiring 81, a pad 8
2, lands 83 of through holes, and the like. The metal surfaces of the pads 82 and the lands 83 of the conductor patterns 8 are exposed to join the mounted components.

[0003] The other portions are covered with a solder resist 7 as shown by the thin oblique lines in FIG. On the solder resist 7, marks 6 for designating mounting components are formed as shown by black thick characters or black thick line frames such as F7 and R202 in FIG. The mark 6 is formed by printing a mark ink on the surface of the solder resist 7 as described later. Here, an example of a conventional method of manufacturing a printed circuit board will be described with reference to FIGS.

First, as shown in FIG. 8A, a pad 82 as a conductor pattern is formed on a printed circuit board 5, for example. Next, pretreatment polishing for solder resist printing is performed. Then, as shown in FIG. 8B, the entire surface of the solder resist 7 is printed on the front side of the printed circuit board 5 and further preliminarily dried. Also, as shown in FIG. 8C, the solder resist 7 is printed on the entire back surface of the printed circuit board 5 in the same manner as the front surface side, and is further preliminarily dried. And
On the printed circuit board 5, a mark printing portion and a remaining area where the solder resist is to be left are exposed using a mask and ultraviolet rays (not shown). Next, FIG.
As shown in (1), the printed circuit board 5 is developed to remove the excess solder resist 7 other than the mark printing portion and the remaining area.

Then, the remaining solder resist 7 is cured by heating. Next, as shown in FIG. 9B, a mark 6 is printed on the solder resist 7 on the front side of the printed circuit board 5 and is thermally cured. Similarly, the back side of the insulating substrate 9 is shown in FIG.
As shown in FIG. 3C, the mark 6 is printed on the solder resist 7 and cured by heat. Through the above steps, the printed board 5 having the mark 6 printed on the surface of the printed board 5 is obtained.

[0006]

However, in the conventional method of manufacturing a printed circuit board, as shown in FIGS. 10 and 11, dripping 61 and bleeding 62 of the mark ink occur. That is, in the mark printing process, the mark 6 is printed on the convex solder resist 7 in the mark printing process as shown in FIGS. 9B and 9C. It is caused by protruding from the upper surface of the solder resist 7.

Further, the bleeding 62 of the mark ink is caused by bleeding of excess ink. The bleeding 62 is generated when the printed circuit board 5 is soldered.
This hinders the solder from adhering to the pads 82 and the lands 83, and causes solder joint failure. The present invention
In view of such a conventional problem, an object of the present invention is to provide a method of manufacturing a printed circuit board capable of accurately performing mark printing without causing dripping or bleeding of mark ink.

[0008]

According to the present invention, a printed circuit board is formed by forming a conductor pattern on the surface of an insulating substrate, applying a solder resist on the surface thereof, and sequentially performing an exposure process, a development process, and a curing process on the solder resist. a method of manufacturing a character on the middle solder resist of the step, in forming a mark such as the shape, the solder
After the resist is exposed , the mark
Print, and then develop the solder resist.
And then subjecting the solder resist to a hardening treatment . The most remarkable point in the present invention is that mark printing is performed immediately after exposure processing of the solder resist, and then development processing of the solder resist is performed.

Here, an example of the method of manufacturing a printed circuit board according to the present invention will be described. First, a printed circuit board on which a pattern is formed is prepared. Next, pretreatment polishing for solder resist printing is performed. Then, the entire surface of the solder resist is printed on the front surface side of the printed circuit board, and further pre-dried. Also, on the back side of the printed circuit board,
As in the case of the front side, the entire surface of the solder resist is printed, and further, preliminary drying is performed. Then, a portion of the printed board on which the solder resist is to be left, that is, the surface of the printed board including a mark printed portion other than the heat sink, the pad, and the land is exposed using a mask and ultraviolet rays.

Next, mark printing is performed on the mark printing portion on the front side of the printed circuit board, and the mark ink is pre-cured. Next, on the mark printing part on the back side of the printed circuit board,
As with the front side, mark printing is performed and the mark ink is pre-cured. As a result, the printed circuit board having the solder resist printed on the entire surface of the printed circuit board and having the mark printed on the mark printing section can be obtained. Next, development processing is performed to remove unnecessary portions of the solder resist. Next, thermal curing of the solder resist and the mark ink is performed.

[0011]

In the present invention, mark printing is performed immediately after exposure processing of the solder resist, and then development processing of the solder resist is performed. According to this method, at the time of mark printing, since the surface of the solder resist is smooth, no dripping of the mark ink occurs. Further, since a small amount of bleeding is removed by developing the solder resist, adhesion of mark ink to pads and the like is prevented. Therefore, there is no defective soldering when mounting electronic components. Therefore, according to the present invention, it is possible to provide a method of manufacturing a printed circuit board that can accurately print a mark without attaching mark ink to a pad or the like on the printed circuit board.

[0012]

EXAMPLE 1 A method of manufacturing a printed circuit board according to an example of the present invention will be described with reference to FIGS. First, as shown in FIG.
A printed board 5 on which a conductor pattern such as 2 is formed is prepared. Next, pretreatment polishing for solder resist printing is performed. Next, as shown in FIG. 1B, a solder resist 7 is printed on the entire front surface of the printed circuit board 5 by a single-sided screen printing method. Further, preliminary drying of the printed circuit board is performed. Also, on the back side of the printed circuit board 5,
As shown in FIG. 1C, the solder resist 7 is printed and pre-dried as in the case of the front side.

Then, a portion of the printed circuit board 5 where a solder resist is to be left, such as a mark printed portion, is exposed using a mask and ultraviolet rays. Next, as shown in FIG. 2A, the mark 6 is printed on the solder resist 7 on the front surface side of the printed circuit board 5 using a mark ink by a single-sided screen printing method. Then, the first preliminary curing of the mark ink is performed. Also, as shown in FIG. 2b, the mark 6 is printed on the back side of the printed circuit board 5 as in the front side, and the second pre-curing is performed. Then Figure 2c
Perform development as shown in (1) to remove excess solder resist. Next, final heat curing is performed.

The conditions of each processing step in the method of manufacturing a printed circuit board will be described. The pre-treatment polishing before printing the solder resist was performed by scrub polishing. In the preliminary drying of the solder resist 7 and the second preliminary curing of the mark ink, hot air of 80 ° C. is applied for 10 minutes.
C. hot air was blown for 5 minutes, and 150 ° C. hot air was blown for 30 minutes in the final heat curing. Exposure is 400mj
/ Cm ^{2 with} an ultraviolet scattering light exposure machine. In development,
Spraying was performed for 1 minute with a developer containing 1% NaCO ₃ . FIG. 3 is a cross-sectional view of a printed circuit board obtained by the above method, and FIG. 4 is a perspective view of the printed circuit board.
As shown in both figures, the mark 6 is formed only on the solder resist 7, and there is no dripping or bleeding of the mark ink on the pad 82.

As described above, in the printed circuit board manufacturing method of this embodiment, mark printing is performed immediately after the exposure processing of the solder resist 7, and then development processing of the solder resist is performed. According to this method, when printing the mark, the entire surface of the solder resist 7 is smooth, so that no dripping of the mark ink occurs. Then, even if the bleeding of the mark ink occurs, the bleeding portion is removed by the developing process of the solder resist 7. Therefore, the adhesion of the mark ink to the pads 82 and the like can be prevented, and there is no occurrence of a defective soldering at the time of mounting electronic components.

Embodiment 2 A method of manufacturing a printed circuit board according to this embodiment is shown in FIG.
Solder resist and marks are printed simultaneously on both the front and back sides of a printed circuit board. That is, first, as shown in FIG. 5A, a printed circuit board 5 on which a pattern is formed is prepared and polished in a pretreatment. Next, as shown in FIG. 5B, a solder resist 7 is printed on both sides of the printed circuit board 5 by a double-sided simultaneous screen printing method. Then, as in the first embodiment, preliminary drying and exposure are performed. Next, FIG.
As shown in FIG. 3C, the marks 6 are printed on both sides of the printed circuit board 5 by the double-sided simultaneous screen printing method. Then, it is pre-cured. Thereafter, similarly to the first embodiment, as shown in FIG. 5D, the solder resist 7 is developed and final heat curing is performed. The conditions of each processing step in the above-described method for manufacturing a printed circuit board are the same as those in Example 1 except that preliminary curing after mark printing was performed for 20 minutes.

In this embodiment, as in the first embodiment, a printed circuit board on which the mark 6 is accurately printed can be obtained. Furthermore, in the manufacturing method of this embodiment, since the solder resist 7 and the mark 6 are simultaneously screen-printed on both sides, productivity can be improved. In addition, at the time of pre-curing before development, the pre-drying time of the mark can be made longer than in the case of Embodiment 1, so that the adhesion between the solder resist and the mark ink at the time of development can be more easily ensured. Also, in this embodiment, the same effect as in the first embodiment can be obtained.

Embodiment 3 As shown in FIGS. 6 and 7, a method of manufacturing a printed circuit board according to the present embodiment
After forming a mark 6 and performing a developing process, a solder resist 7 and a mark 6 are formed on the back surface side, and the developing process is performed. That is, as shown in FIG. 6A, a printed circuit board 5 on which a pattern is formed is prepared and polished in a pretreatment. Next, as shown in FIG. 6B, a solder resist 7 is printed on the front side of the printed circuit board 5 by a single-sided screen printing method.
Then, preliminary drying and exposure are performed. Next, as shown in FIG. 6C, the mark 6 is printed on the solder resist 7 by a one-sided screen printing method, and is pre-cured. next,
As shown in FIG. 6D, the excess solder resist is removed by development, and then heat-cured. First of all,
The solder resist 7 and the mark 6 can be formed only on the front side of the printed circuit board 5.

Further, on the back side of the printed circuit board 5, similarly to the front side, as shown in FIGS.
Print and expose solder resist 7 and then mark 6
To form The conditions of each processing step in the above manufacturing method are the same as those in Example 1 except that the pre-curing after the mark printing was performed for 20 minutes. Example 1 by the above method
Similarly to the above, a printed board on which the mark 6 is accurately printed can be obtained. Further, according to the manufacturing method of this example, even if the insulating substrate 5 is thin, the solder resist 7 having no development residue remains.
Can be formed.

That is, in FIG. 6B, when the solder resist 7 on the front surface side of the printed circuit board is exposed, if the insulating substrate 1 is thin, the irradiation light is transmitted to the rear surface side, and back exposure may occur. . However, in this example, the solder resist 7 has not yet been printed on the back side. Therefore, even if the insulating substrate 1 is thin, there is no residual development of the solder resist on the portion where the solder resist is to be removed. Therefore, according to the manufacturing method of this embodiment, accurate mark printing can be performed without adhesion of the mark ink to the pad, and a printed board having no development residue of the solder resist even on a thin insulating substrate can be obtained. be able to.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a manufacturing process of a printed circuit board according to a first embodiment.

FIG. 2 is an explanatory view of a manufacturing process following FIG. 1;

FIG. 3 is a cross-sectional view of a main part of the printed circuit board according to the first embodiment.

FIG. 4 is a perspective view of a main part of a printed circuit board in the first embodiment.

FIG. 5 is an explanatory view of a printed circuit board manufacturing process in the second embodiment.

FIG. 6 is an explanatory diagram of a printed circuit board manufacturing process in the third embodiment.

FIG. 7 is an explanatory view of the manufacturing process following FIG. 6;

FIG. 8 is an explanatory view of a printed circuit board manufacturing process in a conventional example.

FIG. 9 is an explanatory view of the manufacturing process following FIG. 8;

FIG. 10 is a sectional view of a main part of a printed circuit board in a conventional example.

FIG. 11 is a perspective view of a main part of a printed circuit board in a conventional example.

FIG. 12 is a plan view of a main part of a printed circuit board in a conventional example.

[Explanation of symbols]

 5. . . Printed circuit board, 6. . . Mark, 7. . . 7. Solder resist, . . Conductor pattern, 82. . . Pad, 83. . . Rand, 9. . . Insulating substrate,

Claims (1)

(57) [Claims] 1. A printed circuit board, comprising: forming a conductor pattern on the surface of an insulating substrate; applying a solder resist to these surfaces; and performing an exposure process, a development process, and a curing process on the solder resist in order. In forming a mark such as a character or a shape on the solder resist in the middle of the process, the exposure of the solder resist is performed and then the mark is formed.
Print the mark for forming the solder, and then
And then harden the solder resist
A method for manufacturing a printed circuit board, comprising performing processing .