JPH0444293A - Printed circuit board - Google Patents

Abstract

PURPOSE:To make it possible to effectively utilize the area of a printed circuit board, thereby to package surface packaging parts with high density, by making a through-hole part to conduct to both sides or a conductive part of the internal layer of a printed circuit board in a land part of surface packaging parts, and by coating opening edges of a through-hold part with a conductive material. CONSTITUTION:A through-hole part 7 is made in the same plane of a land part 1 for soldering an electrode part 4 of surface packaging parts 3 including chip parts. The opening edge 8 of the through-hole is coated with conductor foil 9, and makes homogeneous surface as well as that of the land part 1. In addition, the opening edge 8 of the through hole part 7 is sealed with the conductor foil 9 and a conductive material 10. Therefore, there is no worry for inferior soldering performance due to the flow-in of solder 5 in the trhough-hole.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a printed wiring board on which electronic components can be mounted with high density.

BACKGROUND OF THE INVENTION In recent years, printed wiring boards have become very important as they enable higher-density packaging in order to miniaturize electronic devices.

Hereinafter, a conventional printed wiring board will be described with reference to the drawings.

Figure 4 is a plan view showing the state when chip components are mounted at high density on a conventional printed wiring board.
is a chip component 3 provided on the top surface of a printed wiring board 2
Land portions 4 for soldering are electrode portions provided at both ends of the chip component 3, and are soldered to the land portions 1 with solder 5. Reference numeral 6 denotes a through-hole portion for electrically connecting with a conductor portion (not shown) provided on the other surface or inner layer of the printed wiring board 2.

In the printed wiring board 2 configured as described above, the through hole portion 6 is connected to the land portion 1 and provided at one end thereof, and therefore, the area on the upper surface of the printed wiring board 2 is occupied by an area other than the area on which electronic components are mounted. An area for providing the through hole portion 6 is required.

Problems to be Solved by the Invention However, in the above configuration, when chip components 3 and the like are mounted at high density, the area occupied by the through-hole portion 6 provided in the printed wiring board 2 is larger than the area occupied by the chip components 3.
This causes a reduction in the mounting area. On the other hand, when attempting to increase the packaging density by forming through-hole portions 6 inside the land portions 1, when the solder 5 melts in the reflow soldering method, it flows into the through-hole portions 6 and chips There is a problem in that the amount of solder 5 used to connect components 3 and the like becomes non-uniform, resulting in insufficient soldering quality.

The present invention is intended to solve the above-mentioned problems, and an object of the present invention is to provide a printed wiring board on which surface-mounted components and the like can be mounted with high density.

Means for Solving the Problems In order to achieve the above object, the present invention provides a through-hole section that conducts to the screen or the conductor section of the inner layer of the printed wiring board in the land section for soldering the electrode section of the surface mount component. The opening end of the through-hole portion is coated with a conductive material.

Effect of the Invention With the above-described configuration, the present invention makes it possible to arrange the through-hole portion of the printed wiring board and the land portion for soldering surface-mounted components within the same area, thereby reducing the area of the printed wiring board. It can be used effectively, and therefore even higher density packaging can be achieved.

Embodiment Hereinafter, regarding an embodiment of the present invention, parts that are the same as those in FIGS. 1 to 3 and 4 will be given the same reference numerals, detailed explanations will be omitted, and differences will be explained.

1 and 2 show the configuration of an embodiment of the present invention, in which the through hole portion 7 is provided inside the land portion 1.
The opening end 8 of the through hole 7 is covered with a conductive foil 9 made of copper foil or the like. Further, the inside of the through hole 7 is filled with a conductive material 10 made of a conductive paste, a metal wire, a copper plating material, or the like.

Next, the operation of the above configuration will be explained.

In the above embodiment, the through-hole portion 7 is provided on the same surface of the land portion 1 in order to solder the electrode portion 4 of the surface-mounted component 3 such as a chip component, and the opening of the through-hole portion 7 is The end 8 is covered with a conductive foil 9 and forms a uniform surface along with the surface of the land portion 1. The second thing I want to do is
As is clear from the figure, there is no need to form a through-hole section 6 connected to the land section 1 as seen in the conventional example, and even higher density mounting is possible. Since it is sealed by the foil 9 and the conductive material 10, the solder 5 will not flow in and the soldering quality will not deteriorate.

Next, the manufacturing method of this example will be explained using FIGS.

As shown in Fig. 3 ta+, a through-hole portion 7 is drilled in a printed wiring board 2 made of glass epoxy/resin etc. with copper foil 11 on both sides using a drill etc. Fig. 3 1b))
A conductive portion 12 (mainly copper) is provided on the inner surface of the through-hole portion 7 and the surface of the copper foil 11 by plating (FIG. 3(C)). Next, a conductive material 10 is formed by filling the inside of the through hole portion 7 with a conductive paste, metal wire, copper plating material, etc. (FIG. 3(d)). Furthermore, after forming a plating layer 13 by plating the surface of these copper foils 11 and the surface of the conductive material 10 that closed the open end 8 of the through-hole portion 7 (FIG. 3(el)), unnecessary portions are etched and wiring is formed. Forming a pattern (Fig. 3 (f)
).

As described above, according to the above embodiment, by forming the through hole portion 7 in the land portion 1 to which the surface mount component is soldered, the area for mounting the surface mount component 3 can be increased, and a higher density can be achieved. Implementation becomes possible.

In addition, as a method for forming the plating layer 13 in this embodiment, it is also possible to press and laminate copper foils in addition to plating copper.

Effects of the Invention As described above, according to the present invention, a through-hole portion that is electrically connected to both surfaces of a printed wiring board or a conductor portion of an inner layer is provided in a land portion for soldering an electrode portion of a surface mount component. - Since the open end of the round part is covered with conductive foil, there is no need to provide a through hole part other than the land part, and the area of the printed wiring board can be used effectively, so surface mount components can be mounted at high density. This has the effect that it can be implemented in

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part showing the configuration of a printed wiring board according to an embodiment of the present invention, FIG. 2 is a partial plan view showing a state in which surface-mounted components are mounted on the same printed wiring board, and FIG.
~(f+ is a process diagram showing the manufacturing method of the same printed wiring board, and FIG. 4 is a partial plan view showing a state in which components are mounted on a conventional printed wiring board. 1...Land part, 2 ...Printed wiring board, 3...Chip parts (surface mount parts), 4
... Electrode part, 7... Through hole part,
8... Open end, 9... Conductor foil. Name of agent Patent attorney Shigetaka Awano Haka 12 No. 3 Figure 14 FA 1 --- Uny (Deto-Jisuishu 7-- Suno L-71, -1 Shisho P ε --- Opening tg

Claims (1)

[Claims] A printed wiring board having a double-sided or multilayer structure, wherein a through-hole portion that conducts to a conductor portion on both surfaces or an inner layer is provided in a land portion for soldering an electrode portion of a surface mount component, and the through-hole portion is provided in a land portion for soldering an electrode portion of a surface mount component. A printed wiring board whose open end is covered with conductive foil.