JPH0632079A - Production of metal mask for screen printing - Google Patents

Abstract

PURPOSE:To produce a mask having a high dimensional accuracy by a method wherein a projected part of a first photoresist is provided on a part of a metal plate, this resist is treated to be electrically conductive, a printing pattern of a second photoresist is formed, the surface is electroplated, and a mask partially having a recessed part is formed by removing the aforesaid metal plate and the first and second photoresists. CONSTITUTION:A projected part of a first photoresist 2 is provided on a part of a metal plate 1. The resist 2 is treated to be electrically conductive. A printing pattern of a second photoresist 4 is formed. The surface is electroplated with a metal 6. By removing the metal plate 1, and the resists 2, 4, a title metal mask partially having a recessed part us produced. Namely, since the recessed part is completely integrally formed with the other part, a gap is never generated between the recessed part and the other part during printing, and the strength of the mask is as high as that of a normal metal mask having no recessed part. Therefore, there is no possibility of a leakage of a solder paste and such a danger as a short circuit of an electronic circuit. In addition, since a physical force is not applied, a high dimensional accuracy is obtained.

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 metal mask used for screen-printing a solder paste when surface-mounting an electronic component on a printed circuit board, and more particularly, to a method for manufacturing an electronic mask. The present invention relates to a method for manufacturing a metal mask for printing a solder paste on a printed circuit board partially having protrusions due to mounting of components.

[0002]

2. Description of the Related Art Generally, a solder paste is printed with a metal mask in a state where a printed board, which is an object to be printed, is flat, that is, in a state where no parts are mounted.
However, due to the diversification of electronic devices in recent years, it is often required to mount some parts in advance and then mount other parts again. At this time, the metal mask and the printed circuit board may not come into close contact with each other due to the protrusions of the electronic components already mounted, and printing may be impossible.

As a method for solving this problem,
As in the invention described in JP-A-63-16659,
An opening is provided in the portion of the metal mask where the convex portion of the electronic component hits, and a protective cover is placed in the opening.
The method of printing in Ji has been proposed. However, according to this method, there is a risk that the solder paste may leak from the joint between the protective cover and the metal mask during printing, and the electronic circuit may be shorted. Therefore, the solder paste cannot be printed on the portion where the cutout portion of the squeegee abuts during printing, and the degree of freedom in design is hindered.

Therefore, as in the inventions disclosed in Japanese Utility Model Laid-Open No. 60-29650 and Japanese Utility Model Laid-Open No. 63-106664, there is a method in which a concave portion is provided in a part of a metal mask and a convex portion formed by an electronic component is allowed to escape there. Invented. As a method of forming a concave portion in a part of the metal mask, for example, a portion where the convex portion of the electronic component hits, and a printing pattern is opened by etching or the like, and the opening of the portion where the electronic component hits is previously formed. A method of fixing the bowl-shaped lid that has been created with an adhesive or the like, or after opening only the printing pattern by etching, etc., the convex part of the electronic component is hit by the physical force of a punch or the like. A method of deforming a part is common.

[0005]

However, the former of the above-mentioned recess forming methods has a problem in reliability such as the risk of the adhesive section peeling off during printing, and the latter is deformed by physical force. There is a problem that the distortion caused spreads over the entire pattern and deteriorates the dimensional accuracy during printing. Therefore, the present invention is
An object of the present invention is to provide a method for manufacturing a metal mask for screen printing, which does not have such a problem.

[0006]

According to the present invention, a convex portion is provided on a part of a metal plate by a first photoresist, and then the first photoresist is subjected to a conductive treatment, and further a second photoresist is applied. In the method for producing a metal mask for screen printing, which is characterized by partially forming recesses by performing electrolytic plating after forming a printing pattern by, and removing the metal plate and photoresist. The above problems have been solved.

[0007]

[Operation] According to the present invention, it is possible to easily and surely obtain a metal mask having a concave portion for allowing a convex portion of an electronic device component to escape. Since the concave portion of this metal mask is completely integrated with the other portions, it has the same strength as a normal metal mask having no concave portion.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described with reference to the accompanying drawings. 1A to 1I are views for explaining a process of manufacturing a metal mask according to an embodiment of the present invention. First,
A layer of a photoresist 2 is formed on the surface of a metal plate 1 serving as a plating base material (FIG. 1 (b)), and a photomask 3 in which a portion requiring a recess is drawn is brought into close contact with the layer to form a photomask. The resist 2 is exposed (FIG. 1 (c)). When the photoresist 2 is subjected to a phenomenon treatment after the exposure is completed, the photoresist 2
Since the non-exposed portion is removed and a predetermined pattern is formed on the metal plate 1 (FIG. 1 (d)), the photoresist is subjected to a conductive treatment. The conductive treatment method includes a method of applying a solution of a conductor dissolved or dispersed in a liquid to the photoresist 2 and a method of applying a catalyst for electroless plating to the photoresist and then performing electroless plating. .

Next, a layer of photoresist 4 is formed on the entire surface. The thickness of the photoresist 4 needs to be equal to or larger than the thickness of the metal mask to be created (see FIG. 1).
(E)). Then, a photomask 5 having a printing pattern drawn thereon is brought into close contact therewith, and the photoresist 4 is exposed (FIG. 1 (f)). After the exposure is completed, the photoresist 4 is developed to remove the unexposed portion of the photoresist 4 and form a predetermined pattern on the metal plate 1 (FIG. 1 (g)).

Further, by subjecting the metal plate 1 to electrolytic plating, plating is formed on the metal plate 1 and the photoresist 2 as indicated by 6 in FIG. 1 (h). After that, the metal plate 1, the photoresist 2 and the photoresist 4 are removed to obtain a metal mask partially having a recess (FIG. 1 (i)). The plating material may be nickel or any other material that can withstand printing solder paste. At the time of printing, as shown in FIG.
The convex portion 9 is used while being housed in the concave portion 7 of the metal mask.

[0011]

The metal mask having a partially recessed portion manufactured by the method according to the present invention has the recessed portion and the other portion completely integrated with each other. Has no strength and has the same strength as a normal metal mask with no recesses. Therefore, since the solder paste does not leak out, there is no danger that the electronic circuit is shorted. Further, since a physical force such as a punch is not applied during the manufacturing process, it is possible to manufacture a metal mask with high dimensional accuracy.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a method according to the present invention in the order of steps.

FIG. 2 is a cross-sectional view showing a usage state of the metal mask according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal plate used as a plating base material 2 Photoresist (for concave part formation) 3 Photomask (for concave part formation) 4 Photoresist (for printing pattern formation) 5 Photomask (for printing pattern formation) 6 Plating layer 7 Metal mask recess 8 Printed circuit board 9 Printed circuit board protrusion

Claims (1)

[Claims] 1. A convex portion is provided on a part of a metal plate with a first photoresist, and then the first photoresist is subjected to a conductive treatment, and a printing pattern is formed with a second photoresist. After that, electrolytic plating is performed and the metal plate and the photoresist are removed to partially form recesses, and a method for producing a metal mask for screen printing.