JPH09248975A - Screen plate and method of manufacturing printed wiring board using the same - Google Patents

Abstract

(57) Abstract: [PROBLEMS] To improve the yield of forming a high-density / fine wire conductor pattern in a screen plate used for manufacturing a printed wiring board used in various electronic devices and the like. SOLUTION: A screen plate 4 for printing a printed wiring board.
In, the squeegee 5 is formed in the wide area emulsion non-forming portion 11a in parallel with the sliding direction to form the emulsions 1a to 1c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen plate for manufacturing a printed wiring board used in various electronic devices such as personal computers and word processors, and a method for manufacturing a printed wiring board using the screen plate. .

[0002]

2. Description of the Related Art In recent years, printed wiring boards, which are widely used in various electronic devices, have been remarkably increased in wiring density and surface mounting of electronic parts due to downsizing and multifunction of electronic devices. The conductor pattern formed on the top and the land on which electronic parts are mounted are becoming narrower in pitch, finer in line and smaller in shape, and high resolution and high positional accuracy of the etching resist are required. Is getting more and more difficult.

A conventional method for manufacturing a screen plate and a printed wiring board will be described below. FIG. 4 is a sectional view and a plan view showing a manufacturing process of forming a conductor pattern of a conventional screen plate and a printed wiring board. In FIG. 4, 21 is an insulating substrate, 22 is a copper foil, 23 is an etching resist, 24 is a screen plate for etching resist printing, 25 is an emulsion non-forming portion, 26 is an emulsion forming portion (emulsion portion), 27 is a squeegee, 28 is a gauze, 29 is an emulsion, 30 is a mask film for forming a conductor pattern, 31 is a conductor pattern, and 32 is a peeled emulsion.

The formation of the conductor patterns of the screen plate and the printed wiring board configured as described above will be described below. First, as shown in FIG. 4A, the emulsion 29 is applied and dried on the screen plate 24 woven of a linear synthetic resin in a net form, and the conductive pattern forming mask film 30 and the emulsion surface are brought into close contact with each other. The screen plate is exposed by irradiating with 400 mJ / cm ² of ultraviolet rays.

Next, as shown in FIG. 4 (b), the unexposed portion is developed and removed with water, and dried with warm air at 20 to 40 ° C. Next, as shown in FIG. 4D, a screen plate 24 is placed on the copper clad laminate 21 cut into a predetermined size, an etching resist ink is applied on the screen plate, and the squeegee 27 is placed on the screen plate. By sliding on the top, the etching resist ink is printed and transferred onto the copper-clad laminated substrate. next,
Ultraviolet irradiation of 800 to 1500 mJ / cm ² is performed to cure and form an etching resist. The etching resist non-forming portion is etched using a solution of cupric chloride or the like, and the etching resist is peeled off to form a conductor pattern 31 as shown in FIGS. 4 (e) and 4 (f).

[0006]

Although there are photo-developing methods such as dry film and electrodeposition resist in order to cope with high-density wiring, it is difficult to form a conductor pattern on a printed wiring board in terms of productivity and cost. The screen printing method is often used as described above. However, in the conventional manufacturing method,
As shown in FIG. 4 (c), the emulsion forming portion 26 adjacent to the large area emulsion non-forming portion 25 receives the friction of sliding by the squeegee in a concentrated manner, so that the emulsion 32 is easily peeled off from the gauze 28 of the screen. The etching resist ink is not transferred and printed due to clogging of the gauze 28 of the non-emulsion forming portion 25, and the conductor pattern is lost or broken by etching as shown in FIGS. 4 (e) and 4 (f), and the reliability of the printed wiring board is impaired. There was a problem.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a printed wiring board that significantly improves the yield of the manufacturing process and also improves the reliability of electronic equipment.

[0008]

To achieve this object, the present invention achieves the intended object by forming an emulsion in a non-emulsion forming portion having a relatively large area.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is a screen plate in which an emulsion is formed in a relatively large area of the non-emulsion forming portion. It has the effect of reducing the concentrated load on the emulsion portion adjacent to the emulsion non-forming portion having a large area, and can prevent the emulsion from peeling off.

The invention according to claim 2 is the screen plate according to claim 1 in which a dot-like or linear emulsion is formed in the emulsion non-forming part, and the concentrated load on the emulsion forming part is reduced. In addition, when the etching resist is formed, a desired print pattern can be formed without causing a defective portion.

The invention according to claim 3 is the screen plate according to claim 2, wherein the emulsion is formed only in the relatively large area of the non-emulsion forming portion among a plurality of non-emulsion forming portions adjacent to each other. That is, it is possible to reduce the concentrated load on the emulsion forming portion and to form a desired print pattern without forming a defect when forming an etching resist having a relatively large area and a relatively small area. Have.

The invention according to claim 4 provides the screen plate according to claim 3, in which an emulsion having a higher density of emulsion formation is formed toward an emulsion non-forming portion having a relatively narrow area. It has the effect of dispersing the concentrated load on the emulsion forming part.

The invention according to claim 5 is the screen plate according to claim 2 in which the emulsion is formed in parallel and continuously with the sliding direction of the squeegee, and the concentrated load on the emulsion forming part is prevented without interruption. It has the effect of being able to.

According to a sixth aspect of the present invention, there is provided a step of forming an etching resist on a copper foil on an insulating substrate by using the screen plate according to any one of the first to fifth aspects, and a copper on the insulating substrate. This is a method for manufacturing a printed wiring board that has a step of etching foil, and uses a screen plate that can reduce the concentrated load on the emulsion forming part due to squeegee sliding during printing and prevent emulsion peeling. , The etching resist ink is smoothly printed and transferred to the copper foil on the insulating substrate to form an etching resist, and the copper foil is etched to form a conductor pattern, which has the effect of producing a high-quality printed wiring board. .

Embodiments of the present invention will be described below with reference to FIGS. 1, 2 and 3.

(Embodiment 1) FIG. 1 is a top view showing details of a screen plate according to Embodiment 1 of the present invention, and FIGS. 2 (a) to 2 (c) and 3 (a) to 3 (c). [Fig. 4A] is a view showing a manufacturing process of the screen plate in the first embodiment of the present invention. 1 to 3, 1 is an emulsion, 2 is a gauze, 3 is a pattern forming mask film, 4 is a screen plate, 5 is a squeegee, 6 is an etching resist ink, 7 is an insulating substrate, 8 is a copper foil, 9 Is a conductor pattern, 10 is an emulsion forming portion, and 11 is an emulsion non-forming portion. In the screen plate 4 for printing of the printed wiring board, the mesh gauze 2 in the stainless steel frame is used.
Photosensitive emulsion 1 is applied to the fixed one, and 20 to 40
Dry with warm air of ℃, vacuum-contact the mask film 3 for pattern formation as shown in FIG.
UV exposure of 0 mJ / cm ² is performed. Next, as shown in FIG. 2B, the photosensitive emulsion 1 in the unexposed portion is swollen and developed with water and dried with warm air at 20 to 40 ° C. 1 and 2
40 to 6 in the large area non-emulsion forming portion 11a as shown in (b).
Emulsions 1a to 1c having a width of 0 μm are formed in parallel and continuously in the sliding direction of the squeegee, and a linear portion 1a and wide point portions 1 are formed.
b, the screen plate 4 having a narrow dot-like portion 1c is formed, and the density of emulsion formation is increased toward the emulsion non-forming portion 11b side having a narrow area.

Therefore, even if the squeegee 5 slides on the screen plate 4 as shown in FIG. 2 (c), a load is applied without interruption due to the presence of the emulsions 1a to 1c formed parallel to the sliding direction of the squeegee 5. Can be dispersed.

FIG. 3 is a diagram showing a manufacturing process of a printed wiring board. As shown in FIG. 3A, the screen plate 4 is placed on a copper clad laminate cut into a predetermined size, and an etching resist ink is applied to the screen plate 4,
Slide the squeegee 5 over the screen plate 4 to remove the insulating substrate 7.
The etching resist ink is printed and transferred onto the upper copper foil 8. At this time, approximately 40 linear and dot-shaped emulsions 1a to 1c are present in the wide area non-emulsion forming portion 11a of the screen plate 4.
It is formed with a width of up to 60 μm, but the etching resist 6 can be formed on the copper foil 8 without causing a defect due to the bleeding around the substrate contact surface side of the emulsion 1 of the etching resist ink 6 or bleeding. it can. Then 800
The etching resist 6 is cured by irradiating with ultraviolet rays of up to 1200 mJ / cm ² , and the etching resist 6 and the etching resist 6 are peeled off using a solution such as cupric chloride. Such a conductor pattern 9 is formed.

In the embodiment of the present invention, the emulsion shape is a quadrangle whose longitudinal direction is the sliding direction of the squeegee.
Similar effects can be obtained with a mesh shape, a circular shape, or a triangular shape. Further, the structure of the printed wiring board is a single-sided printed wiring board, but a double-sided / multilayered printed wiring board can be implemented in the same manner.

[0020]

As described above, the present invention uses a screen plate in which an emulsion is formed in an emulsion non-forming portion having a relatively large area,
Since the conductor pattern of the printed wiring board is formed, the concentrated load on the emulsion forming part due to squeegee sliding during printing is reduced, emulsion peeling can be prevented, and the conductor line width can be reduced due to non-transfer of the etching resist ink. Or missing,
Defects such as disconnection and short circuit can be reduced, and the production yield can be improved.

[Brief description of drawings]

FIG. 1 is a plan view showing a screen plate according to a first embodiment of the present invention.

2 (a) to (c) are cross-sectional views showing a method of manufacturing a screen printing plate according to Embodiment 1 of the present invention.

3A to 3C are cross-sectional views, cross-sectional views, and plan views showing a method for manufacturing a printed wiring board of the present invention.

4A to 4C are cross-sectional views showing a conventional method for manufacturing a screen plate, and FIGS. 4D to 4F are cross-sectional views, cross-sectional views, and plan views showing a conventional method for manufacturing a printed wiring board.

[Explanation of symbols]

 1 Emulsion 1a to 1c Emulsion 2 Mesh 3 Pattern forming mask film 4 Screen plate 5 Squeegee 6 Etching resist 7 Insulating substrate 8 Copper foil 9 Conductor pattern 10 Emulsion forming part 11a, 11b Emulsion non-forming part

Claims (6)

[Claims] 1. A screen plate having a relatively large area in which a mesh-like gauze is attached to a plate frame and an emulsion is applied to the gauze in the plate frame to form an emulsion, and the non-formation part of the emulsion is used as a printing pattern. A screen plate with emulsion formed in the non-emulsion formation area. 2. The screen plate according to claim 1, wherein a dot-shaped or linear emulsion is formed in the non-emulsion-formed portion. 3. The screen plate according to claim 2, wherein the emulsion is formed only in an emulsion non-forming portion having a relatively large area among a plurality of emulsion non-forming portions adjacent to each other. 4. The screen plate according to claim 3, wherein the emulsion is formed with a higher formation density as it approaches a non-emulsion forming portion having a relatively narrow area. 5. The screen plate according to claim 2, wherein the emulsion is formed in parallel with the sliding direction of the squeegee. 6. A step of printing an etching resist on a copper foil on an insulating substrate using the screen plate according to claim 1, and a step of etching the copper foil on the insulating substrate. And a method for manufacturing a printed wiring board having the same.