JP3533682B2 - Manufacturing method of 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 used in various electronic devices such as video, word processors and personal computers.

[0002]

2. Description of the Related Art In recent years, with the miniaturization and lightening of electronic equipment, the multifunctionalization, and the increasing number of chips and surface mounting of electronic components mounted on printed wiring boards, high-density wiring has been formed on printed wiring boards. However, higher multilayers and higher accuracy are required. Among them, the solder resist forming method for printed wiring boards, which can respond to high precision and high quality of soldering in electronic component soldering, which has a great influence on the reliability of electronic equipment, is better than the conventional screen printing method. A photographic developing method with high image quality is being replaced.

A method of manufacturing a solder resist for a printed wiring board using a conventional photographic development method will be described below.

FIG. 2 shows a method for manufacturing a solder resist for a printed wiring board using a conventional photographic development method.
In FIG. 2, 1 is a printed wiring board, 1a is an insulating substrate,
1b is a copper foil, 1c is a conductor pattern obtained from the copper foil 1b, 2 is an etching resist, 3 is a solder resist,
3a is a photographic development type solder resist ink, 4 is a road map, 5 is ultraviolet rays generated from a high pressure mercury lamp, and 6 is a mask film for forming a solder resist.

A method of manufacturing the printed wiring board having the above structure will be described. First, the copper foil 1b of the copper clad laminate obtained by laminating the copper foil 1b on the insulating substrate 1a cut to a predetermined size is etched as shown in FIG. 2A using a screen printing method or a photo developing method. A resist 2 is formed. Then, the copper clad laminate having the etching resist 2 formed thereon is etched with a chemical solution such as cupric chloride to etch the copper foil 1b having no etching resist 2 formed thereon, and then the etching resist 2 is peeled off. As shown in (b), a printed wiring board 1 having a conductor pattern 1c and lands for soldering electronic components formed on an insulating substrate 1a.
To get

Next, the printed wiring board 1 on which the conductor patterns 1c and lands for soldering electronic parts are formed is shown in FIG.
As shown in (c), a photo-developing solder resist ink 3a is applied on the entire surface by a method such as a screen printing method, a spray method or a curtain coater method, followed by touch-drying.

The printed wiring board 1 is then dried by touch.
2 is conveyed to the exposure device, aligned with the solder resist forming mask film 6 as shown in FIG. 2 (d) and brought into close contact therewith, and then the radiation wavelength range generated from the mercury lamp in the exposure device is 300 to 300 nm. Approximately 1 by 400 nm UV light 5
The integrated light amount is exposed for about 0 to 15 seconds at about 250 to 300 mj / cm ² .

The exposed printed wiring board 1 is developed by removing the unexposed portion of the photographic developing type solder resist ink 3a with a developing solution of a predetermined component, and the printed wiring board 1 is dried at a temperature of 150 to 180 ° C. by a hot air circulation dryer or the like. By performing the heat treatment for about 1 hour, the characteristics such as the solder resist adhesion and hardness are improved, and the solder resist 3 is formed on the printed wiring board 1 as shown in FIG.

Next, the roadmap ink is printed by screen printing on the insulating substrate 1a of the printed wiring board 1 and on the formed solder resist 3, and the temperature of 150 to 1 is obtained.
After the heat treatment is performed at 80 ° C. for about 20 minutes, as shown in FIG. 3 (f), it is a character symbol such as the mounting position, shape and type of the electronic component mounted on the printed wiring board 1. A road map 4 is formed.

[0010]

However, in the above-mentioned conventional structure, the exposure time of the photo-developing solder resist ink 3a and the photo-developing solder resist ink 3a after development are increased.
In addition, since the heating temperature of the roadmap ink after printing is high and the heat treatment time is long, the manufacturing process of forming the solder resist 3 and the roadmap 4 of the printed wiring board 1 is complicated and long. is there. In particular,
In the exposure process of the photo-developing type solder resist ink 3a, the printed wiring boards must be exposed one by one, so the exposure process of the printed wiring boards becomes a stop point of all the processes, which is a bottleneck in improving the throughput. It was

Furthermore, from the high pressure mercury lamp, ultraviolet rays 5
The heat generated together causes a dimensional change or distortion in the mask film 6 for forming the solder resist, which makes it difficult to form the solder resist 3 with high positional accuracy and the insulating substrate 1.
Since excessive heat shrinkage occurs in a, the printed wiring board 1 is warped more than allowable, and it becomes difficult to perform accurate alignment between the print bed of the printing press and the printed wiring board 1 during roadmap ink printing. However, there is a problem that the manufacturing yield in the roadmap 4 forming step is significantly reduced.

The present invention solves the above-mentioned conventional problems, and simplifies the steps of forming a solder resist and a roadmap of a printed wiring board, and at the same time manufactures a printed wiring board with high accuracy and high yield. The purpose is to provide a method.

[0013]

In order to achieve this object, a method of manufacturing a printed wiring board according to the present invention is directed to a printed wiring board on which a conductor pattern is formed by applying a photo-developing solder resist ink to an ultraviolet radiation region. And developing in the visible region, exposing the developed photo-developing solder resist ink in the ultraviolet radiation region, printing a roadmap on the printed wiring board or photo-developing solder resist ink, and heat treatment It consists of a process and.

[0014]

With this structure, the exposure of not only the ultraviolet region but also the visible region can accelerate the polymerization of the photographic development type solder resist ink, which can be exposed in a short time and the throughput of the printed wiring board can be remarkably improved. You can In addition, the photo-developing type solder resist ink formed after development is exposed to ultraviolet rays, and the heat treatment of the photo-developing type solder resist ink and the heat treatment after printing the roadmap ink are performed separately. This can be performed simultaneously, and it is possible to suppress the occurrence of warpage due to contraction of the printed wiring board due to cumulative heating, and it is possible to realize a highly accurate printed wiring board and an efficient method for manufacturing the printed wiring board.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a method of manufacturing a printed wiring board according to the first embodiment of the present invention. In FIG. 1, 11 is a printed wiring board, 11a is an insulating substrate, and 11b.
Is a conductor pattern, 12 is a solder resist, 12a is a photo-developing solder resist ink, 13 is a road map, 1
Reference numeral 4 is a light ray A emitted from the metal halide lamp, 15 is a light ray B emitted from the low-pressure mercury lamp, and 16 is a mask film for forming a solder resist.

A method of manufacturing the printed wiring board having the above structure will be described below.

First, the insulating substrate 11 cut into a predetermined size.
An etching resist is formed on the copper foil of the copper clad laminate in which the copper foil is laminated on a by screen printing or photo development. Then, the copper clad laminate having the etching resist formed thereon is etched with a chemical solution such as cupric chloride to etch the copper foil having no etching resist formed thereon, and then the etching resist is peeled off to form a conductive pattern 11b or an insulating pattern on the insulating substrate 11a. A printed wiring board 11 having lands for soldering electronic components is obtained.

Next, as shown in FIG. 1A, a method such as a screen printing method, a spray method or a curtain coater method is applied to the printed wiring board 11 on which the conductor patterns 11b and lands for soldering electronic parts are formed. Photographic development type solder resist ink (for example, Taiyo Ink Co., Ltd .; PSR-4000) 12a is applied to the entire surface by using, and then touch dry.

Next, the printed wiring board 11 on which the photographic development type solder resist ink 12a that has been dried by touch is formed is conveyed to the exposure device and the mask film 16 for forming the solder resist formed of polyester is aligned. 1B, the radiation wavelength range of ultraviolet rays generated from the metal halide lamp in the exposure apparatus is 300 to 400 nm and the visible radiation wavelength range is 400 nm.
By the light ray A (14) in the ~ 600 nm portion, the integrated light amount 2
It is exposed for 50 to 300 mj / cm ² (about 5 to 10 seconds).

Next, the exposed printed wiring board 11 is
As shown in FIG. 1 (c), an unexposed portion of the photographic development type solder resist ink 12a is developed and removed by a developer containing an alkaline aqueous solution containing sodium carbonate as a main component, washed with water and dried, and then transferred to an irradiation device. Be transported.

Printed wiring board 11 conveyed to the irradiation device
Is a light beam B emitted from a low-pressure mercury lamp in the irradiation device.
In the ultraviolet radiation wavelength region of (15), which has a wavelength range of 200 to 300 nm, the total amount of light 200 mj / cm ² (about 5
And the solder resist 12 is formed.

Due to the irradiation with the light beam B (15) in the short wavelength region, the surface and the layer near the surface of the formed solder resist 12 become strong due to the promotion of polymerization, and become a transport device to the step of forming the road map 13. It is possible to suppress the occurrence of scratches and the like due to mechanical contact with a printing machine for roadmap printing or the like.

The reason for irradiating the light without exposing it to the light of the short wavelength side at the time of exposure is that the ultraviolet light of the short wavelength side (200
(nm or less) prevents the ultraviolet rays (300 nm to 400 nm) necessary for forming the solder resist 12 from passing through the solder resist forming film 16 due to deterioration of the material of the solder resist forming film 16. Because of that.

Next, the insulating substrate 11 of the printed wiring board 11
The roadmap ink is printed by screen printing on the surface a and on the formed solder resist 12, and the temperature of 15
Heat treatment is performed at 0 to 180 ° C. for about 1 hour, and FIG.
As shown in, a road map 13 is formed on the printed wiring board 11, which is a character symbol such as the mounting position, shape, and type of the electronic component to be mounted.

The amount of warpage that occurs in the printed wiring board in the method for manufacturing a printed wiring board according to this embodiment is 1 to 3 mm at maximum when the size of the printed wiring board is 500 mm × 500 mm, which is a conventional method for manufacturing a printed wiring board. The amount of warpage generated in the printed wiring board at 10 to 15 mm can be reduced. Therefore, accurate alignment between the print bed of the printing machine and the printed wiring board is facilitated during roadmap ink printing, and roadmap formation defects due to warpage of the printed wiring board in the roadmap formation process can be reduced to almost zero. The effect was obtained.

As described above, according to this embodiment, the exposure time of the photographic development type solder resist ink dried by touch with the finger can be treated in a short time of about 50% of that in the conventional case, so that the printed wiring board can be processed. The manufacturing yield of can be significantly improved.

Further, the heat treatment by a hot-air circulation dryer after the exposure and development of the photo-developing type solder resist ink, which has conventionally been performed separately, and the heat treatment by a hot-air circulation dryer after the printing of the roadmap ink, etc. Since and can be done at the same time after printing the roadmap ink,
It is possible to suppress the occurrence of warpage due to the shrinkage of the printed wiring board due to the heat treatment at the time of forming the solder resist, and it is possible to easily realize accurate alignment at the time of roadmap ink printing.

By using a microwave type electrodeless mercury lamp instead of the low-pressure mercury lamp as the light source of the light ray A, it becomes possible to cope with the case where the photographic developing type solder resist ink is relatively thick.

Further, in this embodiment, the printed wiring board 1 is used.
Although 1 is a single-sided printed wiring board, it may be a double-sided printed wiring board, a multilayer printed wiring board, or the like.

[0031]

As described above, according to the present invention, by exposing the visible region as well as the ultraviolet region, it is possible to accelerate the polymerization of the photographic development type solder resist ink, and it is possible to perform the exposure in a short time. The manufacturing throughput can be significantly improved. In addition, by irradiating the photo-developing solder resist ink formed after development with an ultraviolet region, the heat treatment of the photo-developing solder resist ink and the heat treatment after roadmap ink printing can be performed at the same time. As a result, it is possible to suppress warpage due to contraction of the printed wiring board due to thermal heating, and it is possible to realize an excellent printed wiring board manufacturing method capable of manufacturing a high-precision printed wiring board.

[Brief description of drawings]

FIG. 1 is a sectional view of each step of a method for manufacturing a printed wiring board according to an embodiment of the present invention.

FIG. 2 is a sectional view of each step of a conventional method for manufacturing a printed wiring board.

[Explanation of symbols]

11 Printed wiring board 11a insulating substrate 11b Conductor pattern 12 Solder resist 12a Photographic solder resist ink 13 Roadmap 14 Ray A 15 Ray B 16 mask film

Claims (2)

(57) [Claims] 1. A step of applying a photo-developing solder resist ink on a printed wiring board on which a conductor pattern is formed, exposing and developing with light in the ultraviolet radiation region and the visible region, and the developed photo-developing solder resist ink. A method for producing a printed wiring board, comprising: a step of irradiating the substrate with light in an ultraviolet radiation region; and a step of printing a road map on a printed wiring board or a photo-developing solder resist ink and performing heat treatment. 2. A photographic development type solder resist ink is used.
UV radiation wavelength range of 0 to 400 nm and 400 to 600 n
The photo-developing solder resist ink formed after development by exposure with light in the visible radiation wavelength range of m is 100 to 300.
The method for manufacturing a printed wiring board according to claim 1, wherein the irradiation is performed with light in the ultraviolet radiation wavelength region of nm.