JPH0714674U - Printed wiring board - Google Patents

Abstract

(57) [Abstract] [Purpose] To eliminate the solder balls generated by soldering when mounting electronic components. [Structure] A metal pattern 3 is formed around the electronic component mounting land 2. Even if the solder balls generated by the soldering are scattered around, they disappear because they are soldered by the metal pattern 3.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a printed wiring board for connecting and assembling at least one electronic component by soldering.

[0002]

[Prior art]

 As a conventional technique for mounting an electronic component on a printed wiring board by soldering, there is known one disclosed in Japanese Utility Model Laid-Open No. 64-42769. FIG. 6 shows this conventional technique, and includes a hot air jet head 61 for jetting heated air, an arm 62 for supporting the hot air jet head 61, and an air nozzle 63 for jetting air heated by the hot air jet head 61 to scatter solder. A particle removal device is configured. In this device, the air nozzle 63 is brought close to the leads 66 of the electronic component 65 soldered to the printed wiring board 64, and moves along the array of the leads 66, and blows out by blowing hot air higher than the melting point of the solder. This removes the solder balls that have been removed.

[0003]

[Problems to be solved by the device]

 In the above-mentioned conventional technique, the solder balls scattered at the time of soldering the leads 66 can be removed from the mounting part of the electronic component 65, but in the actual production, the solder balls scatter to other parts on the printed wiring board. This solder ball has to be removed separately, which is troublesome, and a scattered solder particle removing device has to be used, and its operation is complicated and there is a problem of poor operability.

The present invention has been made in consideration of the above circumstances, and an object thereof is to provide a printed wiring board having a structure for removing solder balls with a simple improvement.

[0005]

[Means and Actions for Solving the Problems]

 As shown in FIG. 1, a printed wiring board 1 of the present invention has at least one or more electronic component mounting lands 2 and a solderable metal pattern 3 provided in the vicinity of the electronic component mounting lands 2. And are provided. According to the above configuration, the solder supplied to the electronic component mounting land 2 is melted by heating and the solder balls are scattered around the land 2, but the scattered solder balls are scattered around the solder ball in advance. Sn drops, which are metal atoms in the solder ball, enter the fine gaps on the metal surface of the metal pattern 3 and diffuse, forming an alloy layer and soldered to the metal pattern 3. As a result, the scattered solder balls disappear. Particularly in soldering using cream solder, the solder particles in the cream solder may flow and spread to the outside of the electronic component mounting land 2 due to softening of the flux component during the temperature rise. Even if the solder particles reach the temperature at which the cream solder melts, they may not be integrated and may remain as solder balls around the electronic component mounting land 2. However, in the above configuration, due to the surface tension of the solder itself, soldering may occur. Since it is drawn into either the possible metal pattern 3 or the electronic component mounting land 2, the solder ball can be eliminated.

[0006]

Embodiment 1 FIGS. 2 and 3 show Embodiment 1 of the present invention, in which the same elements as in FIG. 1 are designated by the same reference numerals. A plurality of electronic component mounting lands 2 and a metal pattern 3 provided around the lands 2 so as to surround the lands 2 are arranged on the printed wiring board 1. In this case, the flux 3a is applied to the upper surface of the metal pattern 3 as shown in FIG.

In the above configuration, the cream solder supplied to the electronic component mounting land 2 is melted by heating and the solder balls are scattered around. However, the metal pattern 3 coated with the flux 3a removes the scattered solder balls. Since it is soldered, it can be eliminated. Therefore, in the present embodiment, even with respect to the solder balls which are scattered and are not easily subjected to the flux effect and the solderability is poor, the flux 3a applied to the metal pattern 3 can sufficiently exert the effect and soldering can be performed. You can make the solder ball disappear.

[0008]

Second Embodiment FIG. 4 shows a second embodiment of the present invention. In this embodiment, a large number of electronic component mounting lands 2 are pattern-formed side by side on a printed wiring board 1. The metal patterns 3 are arranged around the electronic component mounting lands 2, but the metal patterns 3 between the adjacent lands 2 are common to the lands 2.

Also in this embodiment, the cream solder supplied to the electronic component mounting land 2 is melted by heating and the solder balls are scattered, but the scattered solder balls disappear because the metal pattern 3 is soldered. be able to. According to the present embodiment, there is an advantage that it can be applied to the arrangement of the densified lands for mounting electronic components.

[0010]

Third Embodiment FIG. 5 shows a third embodiment of the present invention. In this embodiment, the metal pattern 3 is formed around the electronic component mounting land 2, but the lip portion 4 extending in the direction of the electronic component mounting land 2 is integrally formed with the metal pattern 3. The lip portion 4 is provided corresponding to a place where a large amount of solder balls are produced. Also in this embodiment, the cream solder supplied to the electronic component mounting land 2 is melted by heating and the solder balls are scattered, but disappears because the solder balls are soldered by the metal pattern 3 provided with the lip portion 4. Can be made. According to the present embodiment, it is possible to sufficiently absorb and eliminate the solder balls even in a place where the amount of generated solder balls is large.

[0011]

[Effect of device]

 As described above, in the present invention, since the metal pattern is provided around the electronic component mounting land, the solder balls scattered during soldering can be easily removed.

[Brief description of drawings]

FIG. 1 is a plan view showing the basic configuration of the present invention.

FIG. 2 is a plan view showing a first embodiment of the present invention.

3 is a cross-sectional view taken along the line AA in FIG.

FIG. 4 is a plan view showing a second embodiment.

FIG. 5 is a plan view showing a third embodiment.

FIG. 6 is a perspective view showing conventional soldering.

[Explanation of symbols]

 1 printed wiring board 2 land for mounting electronic components 3 metal pattern

Claims (1)

[Scope of utility model registration request] 1. In a printed wiring board for connecting electrodes of an electronic component by soldering, at least one or more electronic component mounting lands and a solderable metal provided in the vicinity of the electronic component mounting land. A printed wiring board having a pattern.