JPH05267802A - Printed wiring board for surface mounting - Google Patents

Abstract

(57) [Summary] [Purpose] In printed wiring boards used for various electronic devices, etc., eliminate solder resist residue in the recognition mark area and eliminate recognition errors of automatic component mounters.
An object of the present invention is to provide a surface-mounting printed wiring board that improves production in an electronic device manufacturing process. [Structure] By arranging a recognition mark 12b around the recognition mark 12b for image processing of an automatic component mounting machine and providing an independent conductor pattern 12a, the solder resist ink for photographic development is exposed. The ultraviolet light incident on the boundary between the non-light-shielding portion and the light-shielding portion of the mask film, transmitting the solder resist ink for photo development, and reflected by the surface portion of the insulating substrate 11 is blocked by the conductor pattern 12a formed around the recognition mark 12b. It is possible to prevent the polymerization of the solder resist ink for photographic development in the solder resist non-formed portion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mounting printed wiring board used in various electronic devices such as personal computers and word processors.

[0002]

2. Description of the Related Art In recent years, printed wiring boards, which have been widely used in various electronic devices, have increased wiring density and increased use of surface mount electronic components as electronic devices have become smaller, lighter and more multifunctional. However, electronic components are being mounted almost by automatic component mounters. Therefore, the printed wiring board is required to have high reliability. Especially in the case of the surface mounting printed wiring board for automatic mounting, it is necessary to recognize various automatic mounting machines for image processing so that electronic components can be surely mounted at predetermined positions. Marks are being provided on printed wiring boards.

A conventional surface mount printed wiring board will be described below. FIG. 4 shows the recognition mark area and shape of the conventional surface-mounting printed wiring board as shown in FIG.
(F) shows a manufacturing process of forming a solder resist in a recognition mark area of a conventional surface mounting printed wiring board. In the figure, 1 is an insulating substrate, 2a is a conductor pattern, 2b is a recognition mark, 3a is a photographic developing solder resist ink, 3b is a formed solder resist, 4
Is a mask film for forming a solder resist, 5 is ultraviolet light for exposure, and 6 is a residual solder resist after development.

The operation of forming the solder resist in the recognition mark area of the surface-mounting printed wiring board having the above structure will be described below.

First, an etching resist is formed on a copper clad laminate (not shown) obtained by laminating a copper foil on a glass cloth base epoxy resin laminate by a screen printing method or a photo developing method, and then a second chloride Etching is performed using a solution of copper or the like, and as shown in FIG.
a and the recognition mark 2b are formed, and the etching resist is peeled off. Next, as shown in FIG. 5 (b), the photographic developing solder resist ink 3a is applied onto the insulating substrate 1 on which the conductor pattern 2a and the recognition mark 12b are formed, and dried by touching with hot air or the like. Next, FIG. 5 (c)
As shown in FIG. 5D, after the mask film 4 for forming the solder resist is brought into close contact with the surface of the solder resist ink 3a for photographic development which has been dried by touch with the finger, and exposed by the ultraviolet light 5.
As shown in FIG. 3, the unexposed portion is developed with a predetermined developing solution, and curing is accelerated by hot air or the like to form the solder resist 3b.

After that, the surface-mounting printed wiring board completed through processing steps such as road map formation and outer shape processing is conveyed to an electronic component mounting step, and after application of cream solder, it is mounted on the insulating substrate 1 by an automatic component mounting machine. After the recognition mark 2b formed on the image is subjected to image processing and position correction,
Surface mounting electronic components are mounted at predetermined positions.

[0007]

However, in the above-mentioned conventional configuration, when the photographic developing solder resist ink 3a is of a high sensitivity type, or when the solder resist 3 is formed in a portion where the conductor pattern 2a is not formed in a wide area, that is, the conductor is formed. In the recognition mark 2b area in which the prohibited area of the pattern 2a is set, when the touch-dried solder resist ink 3a for photo development is exposed by the ultraviolet light 5,
As shown in (d), ultraviolet light 5 incident through the mask film 4 for forming a solder resist is transmitted through the photographic developing solder resist ink 3a, and the insulating substrate 1 is etched to have irregularities of about 5 μm at maximum. Diffuse reflection is caused on the surface portion, and the solder resist ink 3a for photographic development in the solder resist non-forming portion is polymerized (hereinafter referred to as halation), and recognition after development is performed as shown in FIGS. 5 (e) and 5 (f). A solder resist residue 6 is generated in the solder resist non-formed portion in the area for the mark 2b. In this solder resist residue 6, the incident ultraviolet light 5 is concentrated at the rectangular corner portion of the light shielding portion even though the light shielding portion corresponding to the solder resist non-forming portion of the mask film 4 for forming the solder resist is rectangular. As shown in FIG. 5 (f), it tends to have a shape close to a hollow circle. Depending on the residual solder resisting amount of about 6, the image processing of the recognition mark 2b by the automatic component mounting machine of the surface mounting printed wiring board becomes unstable, and a recognition error occurs that causes a problem in position correction and mounting of the surface mounting electronic component. However, there is a problem in that it induces and significantly impairs the productivity of the electronic device manufacturing process.

The present invention solves the above-mentioned conventional problems by eliminating residual solder resist due to halation in the recognition mark area of the surface mounting printed wiring board, eliminating the recognition error of the automatic component mounting machine, and An object of the present invention is to provide a surface mounting printed wiring board that improves the production in the device manufacturing process.

[0009]

To achieve this object, a surface mounting printed wiring board according to the present invention has a predetermined area around a recognition mark formed by a conductor pattern for image processing of an automatic component mounting machine. In addition, a conductor pattern surrounding the recognition mark and independent of the recognition mark is provided.

[0010]

With this configuration, coating on the printed wiring board,
When the touch-dried solder resist ink for photo development is exposed to ultraviolet light, the light incident from the solder resist forming part, that is, the boundary between the non-light-shielding part of the mask film and the light-shielding part, passes through the solder resist ink for photo-developing and becomes an insulating substrate. Although it is reflected on the surface of the recognition mark, it is blocked by the conductor pattern formed around the recognition mark, and it becomes possible to prevent ultraviolet light from reaching the solder resist non-formed portion in the recognition mark area. It is possible to prevent polymerization of the solder resist ink for photographic development in the forming part.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the area and shape of the recognition mark in the embodiment of the present invention, and FIGS. 2A to 2C show the solder resist formation in the recognition mark area of the surface mounting printed wiring board in the embodiment of the present invention. 3A and 3B show a manufacturing process, and FIGS. 3A and 3B show regions and shapes of a recognition mark in another embodiment.

In the figure, 11 is an insulating substrate, 12a is a conductor pattern, 12b is a recognition mark, 13a is a solder resist ink for photo development, 13b is a formed solder resist, 14 is a mask film for forming solder resist, and 15 is a mask film. Is ultraviolet light for exposure.

First, prior to the manufacture of a surface mounting printed wiring board, a master film for manufacturing such as a conductor pattern and a solder resist is prepared from information such as a circuit diagram, a component position, a dimension drawing such as an outer shape and a mounting reference position, and a component list. design. When manufacturing the manufacturing master film for the conductor pattern 12a,
A recognition mark 12b for automatic electronic component mounting is provided at a predetermined position, and at the same time, a conductor pattern 12a independent of the recognition mark 12b is provided around the recognition mark 12b area to have a rectangular outer shape and a hollow inner shape as shown in FIG. Give it a circular shape. At the same time, as shown in FIG. 1, the mask film 14 for forming the solder resist 13b is provided with a solder resist pattern in contact with the circular hollow rectangular conductor pattern 12a around the recognition mark 12b of the mask film for forming the conductor pattern 12a. Keep it.

Next, a conductor pattern 12a is formed on a copper clad laminate (not shown) by a method similar to the conventional one, and the insulating substrate 1 on which the conductor pattern 12a is formed as shown in FIG. 2 (a).
1 is coated with an alkali developing type photographic developing solder resist ink 13a by means of screen printing, a roll coater or a curtain coater, and the temperature is 60 to 80 ° C. for about 15 to 30 minutes in a hot air circulating oven or the like. Touch dry under the conditions.

Next, as shown in FIG. 2 (b), a mask film 14 for forming a solder resist is brought into close contact, and ultraviolet light 1 is emitted.
5 and irradiate with a light amount of about 300 to 700 mJ / cm ² . At the time of exposure, the ultraviolet light 15 incident from the boundary between the non-light-shielding portion and the light-shielding portion of the mask film 14 passes through the solder resist ink 13a for photo development and is reflected by the surface portion of the insulating substrate 11, but blocked by the conductor pattern 12a. Also, the ultraviolet light 15 concentrated at the light shielding corners of the solder resist non-forming portion of the mask film 14 is also blocked by the conductor pattern 12a, and the ultraviolet light 15 is reflected to the solder resist 13b non-forming portion in the recognition mark 12b area. Never reach.

Then, as shown in FIG. 2 (c), the unexposed portion is developed and removed with a developing solution containing sodium carbonate as a main component. Then, in order to improve the coating film characteristics of the formed solder resist 13b, a temperature of 130 to 1 is set in a hot air circulation furnace or the like.
Heating is performed under the conditions of 60 ° C. and time of 30 to 60 minutes.

After that, the surface mounting printed wiring board completed through processing steps such as road map formation and outer shape processing is transferred to the electronic component mounting step, and after applying cream solder, it is mounted on the insulating substrate 11 by an automatic component mounting machine. The recognition mark 12b formed on the image is subjected to image processing, and after position correction,
The surface mounting electronic component is mounted at a predetermined position.

In the printed wiring board for surface mounting according to the embodiment of the present invention, no solder resist remains due to halation in the solder resist non-forming portion of the recognition mark 12b area after development, and according to the embodiment of the present invention. When comparing the surface mounting printed wiring board and the conventional surface mounting printed wiring board, the recognition error in the automatic component mounting machine was several percent in the past, but it was completely recognized in the surface mounting printed wiring board of the present invention. There wasn't.

In the embodiment of the present invention, the photographic developing solder resist ink 13a is of the alkali developing type, but the photographic developing solder resist ink 13a may be of the solvent developing type. The conductor pattern 12a around the recognition mark 12b, which is independent of the recognition mark 12b, has a rectangular outer shape and a circular hollow inner shape.
As shown in FIG. 2A, when the hollow inner shape is a quadrangle without a corner, and the recognition mark 12b has a triangular shape, the outer shape and the hollow inner shape may be similar to a triangle as shown in FIG. 2B. Although the surface mounting printed wiring board is a single-sided printed wiring board, it goes without saying that it may be a double-sided or multilayer printed wiring board.

[0020]

As described above, according to the present invention, the recognition mark is enclosed in a predetermined area around the recognition mark formed by the conductor pattern for image processing of the automatic component mounting machine, and the conductor is independent of the recognition mark. By providing a pattern, solder resist residue due to halation in the recognition mark area of the surface mounting printed wiring board can be eliminated, the recognition error of the automatic component mounting machine can be eliminated, and the production of the electronic device manufacturing process can be improved. It is also possible to realize a printed wiring board for surface mounting.

[Brief description of drawings]

FIG. 1 is a plan view of a recognition mark area and a shape of a surface mounting printed wiring board according to an embodiment of the present invention.

2 (a) to 2 (c) are sectional views of essential steps showing a manufacturing process of forming a solder resist of a surface mounting printed wiring board.

3A and 3B are plan views of a recognition mark area and a shape of a surface mounting printed wiring board according to another embodiment of the present invention.

FIG. 4 is a plan view of a recognition mark area and a shape of a conventional surface mounting printed wiring board.

5 (a) to 5 (f) are cross-sectional views and plan views of a main process for explaining a manufacturing process and operation of forming a solder resist of a conventional surface mounting printed wiring board.

[Explanation of symbols]

 11 Insulating Substrate 12a Conductor Pattern 12b Recognition Mark 13a Photographic Solder Resist Ink 13b Solder Resist 14 Mask Film 15 Ultraviolet Light

Claims (2)

[Claims] 1. A recognition mark formed of a conductor pattern for image processing of an automatic component mounting machine, wherein the recognition mark is surrounded by a predetermined area around the recognition mark and is independent of the recognition mark. Printed wiring board for surface mounting with conductor pattern. 2. The printed wiring board for surface mounting according to claim 1, wherein the shape of the conductor pattern surrounding the recognition mark is a hollow quadrangle having a square outer shape and a circular inner shape.