JPH0318092A - Solder plating method for printed circuit board - Google Patents

Abstract

PURPOSE:To attain the uniform thickness of a plated layer and to change the layer thickness partially according to a necessity by a method wherein a cream solder is screen-printed on a copper foil pattern wiring formed on a printed circuit board, after which the printed circuit board after printing is heated in a heating oven to fuse the cream solder and the solder plating is done. CONSTITUTION:On the surface of a copper foil pattern 2 formed on a printed circuit board 1, a resist film is formed except a part 3 prepared for solder plating. A screen film 41 having a mesh part 51 which is the same as the solder plating prepared part 3 in shape and size is printed on the printed circuit board 1, and a cream solder 6' is printed on the prepared part 3 on the copper foil of the printed circuit board 1 while corresponding the mesh part 51 to the prepared part 3. Next, the formed printed circuit board 1 is heated in a heating oven to fuse the cream solder to make the solder plating on the copper foil. Thus, the thickness of a plated layer can be made uniform and the thickness can be changed partially according to a necessity.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is applicable to each l! I This relates to a solder plating method for circuit printed circuit boards used in electronic devices. Unique technology〉 Usually, solder plating is performed to improve the strength of the T14m pattern on the printed circuit board, to improve the cross-sectional area to reduce immunity, or to prevent oxidation of the copper foil surface. However, the method is to solder using a soldering iron! There are two methods: a manual method in which the solder is melted and spread onto the copper foil pattern, and a spray method in which molten solder is sprayed onto the copper foil pattern during the printed circuit board manufacturing process.

The 'fX problem' that the invention aims to solve> However, since the former example described above is done manually, the thickness of the solder plating layer becomes uneven, resulting in unevenness, making it even more difficult to achieve uniform plating, especially when covering a wide area. It is.

In addition, in the latter conventional example, the thickness of the plating layer is several hundred [
μ], which has drawbacks such as not being able to fully satisfy the purpose.

The present invention provides a solder plating method that eliminates the drawbacks of the conventional method and allows the thickness of the plating layer to be made uniform and to locally change the layer thickness as required.

<Means for Solving the Problems> After cream solder is screen printed on the copper foil pattern of a printed circuit board, the printed circuit board is led to and passed through a heating furnace to perform solder plating.

Effect> When the cream solder printed on the 114M pattern passes through a heating furnace, it receives heat and melts, and is welded to the copper foil pattern. Embodiments> Hereinafter, the present invention will be explained in detail using embodiments shown in the drawings. As shown in FIG. 1, solder plating is to be performed on the surface of a copper foil pattern 2 formed on a printed circuit board 1. Shape the resist resin film except for the planned area 3. In this case, the portion 3 to be solder plated may be exposed in the form of a resist resin film or by peeling off afterward.

A screen film 4 is formed with a mesh portion 5 having the same shape and size as the portion 3 to be solder plated. are stacked vertically on the printed circuit board 1, with the mesh portion 51 corresponding to the planned portion 3, as shown in FIG. By moving the cream solder 6 to the screen? Cream solder 6'' is printed on the planned area 3 on fl4M of the printed circuit board 1 through the mesh portion 5I of the film 4. Next, the printed circuit board 1 shaped as shown in Fig. 2 is guided into a heating furnace. By heating, the cream solder melts and solder plating is applied on the g!! foil.

Also, in order to locally change the thickness of the solder plating, as shown in FIGS. 3 and 4, mesh ffls5, 5. By setting the depth alla2 (al≠a2) at four places 4゛, 4'', the mesh part 5 of the screen film 4■
The amount of solder plating that permeates to the printed circuit board side through steps (1) and (5) is controlled, and by heating this, it is possible to form solder plating with locally different thicknesses on f:RY5.

Effects of the Invention The present invention, as described above, allows solder plating with a uniform thickness to be applied to copper foil. Furthermore, it is possible to extremely easily provide solder plating with locally different thicknesses on the same printed circuit board as required. Furthermore, since it is done by printing, mass production is possible, and the plating thickness can be applied without variation as originally planned.

[Brief explanation of drawings]

1 to 4 show an embodiment of the present invention, FIG. 1 is a perspective view showing 58 areas before printing, and FIG. 2 is a vertical I in the printed state.
! FIG. 3 is a partial plan view of the screen film, and FIG. 4 is a longitudinal sectional side view of a printing state different from that in FIG. 2. ? ...Printed circuit board, 2...mti pattern 3...solder plating planned area 4■41...Screen I/Ichigo 7 ilm

Claims (1)

[Claims] 1. A printed circuit board characterized in that after cream solder is screen printed on a copper pipe of pattern wiring on a printed circuit board, the printed printed circuit board is led to and passed through a heating furnace to melt the cream solder and perform solder plating. solder plating method.