JP2000196222A - Manufacture of printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To resolve surface mounting trouble caused by a shape of a print mark formed by a screen print method in a surface of a printed wiring board. SOLUTION: In the manufacturing method of a printed wiring board, after an outer layer circuit conductor 3 of a both-sided and multilayer printed wiring board is formed, a solid print part 8 for a print mark 5 is formed before formation of solder resist, and a solder resist film 4 is formed thereon. As a result, a print mark, etc., are formed by a pattern of solder resist, a wiring board surface can be finished smoothly and part mounting reliability is improved since a surface part can be mounted stably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a printed wiring board for mounting surface-mounted components.

[0002]

2. Description of the Related Art A conventional printed wiring board will be described with reference to FIG. As shown in FIG. 2A, a circuit conductor 3 including a surface-mounted land 2 for component mounting is formed on both surfaces and on the surface of a substrate 1 of a multilayer printed wiring board by a subtractive method or an additive method. Next, FIG.
As shown in (b), a photosensitive solder resist is formed on the entire surface of the outer layer or a predetermined part by a dipping method, a curtain coater method, an electrostatic coating method, a spraying method, a printing method or the like, and is temporarily dried. In the subsequent exposure step, a predetermined mask film is used to block ultraviolet rays from the photosensitive solder resist at the position of the surface mounting land 2 for component mounting on the surface, while the other surface of the surface is protected. The photosensitive solder resist at a desired location is irradiated with ultraviolet rays to be photopolymerized. Next, in the developing step, the ultraviolet light shielding portion is removed and removed, and a cured film of the photosensitive solder resist film 4 is formed in a predetermined shape through the main drying step. Then, as shown in FIG. 2C, in the next step, a marking mark 5 such as a character, a symbol, or a product number for a component mounting or a service mark is formed on a predetermined portion of the upper surface of the solder resist film 4 by a screen printing method. Form. In the above-mentioned conventional method, the marking mark 5 for component mounting, which is formed by the screen printing method and is particularly provided between the surface-mounted land 2 for surface component mounting.
Is a solder bridge prevention coating for preventing poor soldering of surface mount components. Usually, an imposed component is mounted on the marking mark 5 for component mounting in many cases. In this case, the surface mounting components mounted on the conventional convex marking mark 5 formed between the surface-mounted lands 2 for mounting the surface components are mounted in a point contact state, resulting in an unstable mounting state. Therefore, an unstable soldering failure indicating a mounting failure state of the surface-mounted surface-mounted component 6 shown in FIG. Soldering failure).

[0003]

In the above-mentioned conventional example, as shown in FIG.
When the marking mark 5 is installed between the imposed lands 2,
Since a convex portion is formed on the surface of the printed wiring board on which the components are mounted, the surface-mounted components are mounted in a point contact state and become unstable, and mounting failure due to soldering occurs. The present invention eliminates protrusions on the component mounting surface, smoothes the gaps between the surface mounting lands of the surface mounting component, and enables accurate component mounting. This is to improve the mounting reliability.

[0004]

In order to solve the above-mentioned problems, a circuit conductor is formed on a surface of an outer layer of a printed wiring board.
Thereafter, the present invention provides a method for manufacturing a printed wiring board in which solid printing for a marking mark such as a character, a symbol mark, and a product number is performed, and a solder resist film is formed on the upper surface thereof.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described with reference to FIG. In a method of manufacturing a printed wiring board, first, a hole is formed in an arbitrary portion of a double-sided copper-clad laminate or a multilayer printed wiring board in which an inner layer is formed. After that, electrolytic or electroless copper plating is applied to the wiring board surface and the inner wall of the hole,
By connecting through-hole conductors between both surfaces or between the inner layer and the outer layer, a photosensitive film is adhered to the surface, and a surface circuit conductor is formed by a photo tenting method or the like.

FIG. 1A is a perspective view and a sectional view of a printed wiring board formed by the above method. After a surface circuit conductor 3 including a surface-mounted land 2 for component mounting and the like is formed on both surfaces or on the surface of a substrate 1 of a multilayer printed wiring board as shown in FIG. A solid printing unit 8 for a seal mark for mounting is printed by a screen method. In this case, in the area, the solid printing unit 8 for the marking mark actually used is printed with a square, circular, triangular, or irregular shaped filling pattern within a size range in which the marking mark is formed.

Next, as shown in FIG. 1 (c), a photosensitive solder resist is applied to the printed wiring board by a dipping method, a curtain coater method, an electrostatic coating method, a spray method, a printing method, and the like. Preliminary drying is performed at 80 ° C. for 15 minutes.

Thereafter, using a light-shielding mask film having a predetermined shape of the land for soldering such as the surface-attached land 2 and a predetermined display shape of the seal mark 5, exposure with ultraviolet light is performed from directly above, development, and exposure of the light-shielding portion. The conductive solder resist portion is peeled off and a solder resist film 4 is formed on the surface of the printed wiring board so as to expose the imposed land 2 and the marking mark 5. Finally, the formation of the photosensitive solder resist film 4 is completed by performing post-curing at 150 ° C. for 30 minutes.

Through the above steps, the surface of the printed wiring board is formed on the surface of the printed wiring board with a photosensitive solder resist having a predetermined pattern such as a land 2 and a marking mark 5 as shown in FIG. A film 4 is formed. Due to the above surface formation, unlike the conventional marking mark 5 shown in FIG. 2 (c), the surface of the wiring board for the surface mounting component mounted on the mounting surface land 2 is a smooth photosensitive solder having no convex portions. A finer marking mark is formed on the resist surface as compared with a marking mark formed by a conventional printing method. Also,
The imposed components are mounted horizontally and orderly, and the reliability of component mounting is improved.

[0010]

As described above, according to the present invention, the surface between the lands with the surface of the printed wiring board is smoothed by the solder resist, so that the surface-mounted parts are formed at a plurality of points by the solder resist or on a wider plane. In this case, as compared with the case of mounting on a convex marking mark in the related art, more stable, high reliability, high precision, and high density component mounting can be realized. In addition, in the subsequent process of forming the outer shape of the wiring board, the direct impact of the printed display ink can be reduced, so that the additional effect of eliminating the problem of partial peeling or chipping of the marking mark can be obtained. Can be

[Brief description of the drawings]

FIG. 1 is a perspective view and a cross-sectional view showing a procedure of a manufacturing method of the present invention.

2A and 2B are a perspective view and a cross-sectional view illustrating a procedure of a conventional manufacturing method.

[Explanation of symbols]

 1: base material 2: land with surface 3: circuit conductor 4: solder resist film 5: marking mark 6: surface-mounted part 8: solid printed part for marking mark 9: solder fillet

Continued on the front page F term (reference) 5E314 AA27 BB02 BB11 CC03 CC04 CC06 DD07 DD09 FF01 GG17 GG18 5E319 AA03 AB05 AC02 BB01 CC22 GG01 GG03 5E338 AA02 AA16 DD18 DD22 DD32 EE41 EE51

Claims (1)

[Claims] 1. A method of forming a circuit conductor on an outer layer surface of a printed wiring board, performing solid printing for a marking mark for displaying characters, symbol marks, and product numbers, and forming a solder resist film on the upper surface thereof. A method for manufacturing a printed wiring board, which is a feature.