Circuit board device and its mounting method

Abstract

In a circuit board, when lands provided on a rear surface of a substrate are each separated into a mainland and a sub-land, warping or other defects of the substrate can be ignored when soldering, and the substrate can be mounted with a high bonding strength. On the rear surface of a module substrate, partitions are each provided to separate a metal film into the mainland and the sub-land. Accordingly, when the substrate is mounted on a motherboard, solder applied beforehand from each end-surface electrode to the mainland can be largely protruded downward from the mainland, and warping or other defects of the substrate can be ignored by this protruding portion of the solder. In addition, in the state in which the substrate is mounted, since the solder is pushed out from between the mainland and the motherboard and overflows the partition, both the mainland and the sub-land can be soldered to the motherboard side, and hence stable bonding can be obtained at a large bonding area.

Description

technical field [0001] The present invention relates to a circuit board device and its mounting method for partially assembling electronic parts to be suitable for mounting on a mother board. Background technique [0002] Generally, as a circuit board device, for example, there is a structure in which a plurality of electronic components are partially assembled on a module printed circuit board (for example, refer to Patent Document 1). [0003] [Patent Document 1] JP-A-2001-127188 [0004] This circuit board device based on the prior art is composed of the following parts: a printed circuit board with electronic parts mounted on the front side and mounted on the motherboard on the back side; And connected to a plurality of end-face electrodes of electronic parts; connected to the end-face electrodes, and arranged on the back side of the printed circuit board, and soldered together with the end-face electrodes to a plurality of bosses on one side of the motherboard (land)....

AI Technical Summary

Problems solved by technology

[0009] However, if a large boss is formed, the solder that should protrude toward the mother board side will spread and become thinner along the boss during the solder mounting operation, so as long as a large amount of solder does not adhere to the boss, it will cause soldering. Insufficient protrusion size, unable to absorb warping of the printed circuit board, and prone to poor connection of bosses

[0010] In view of this point, when a large amount of solder is attached to the boss, not only the consumption of solder will increase uselessly, but also when the printed circuit board is mounted, the solder that melts and spreads between the boss and the mother board will sometimes cause adjacent There is a short circuit between the bosses, so there is a limit to increasing the amount of solder attached

[0011] Therefore, in the prior art, since it is difficult to obtain a suitable size for the boss area and the protruding size of the solder at the same time, it is impossible to mount the printed circuit board on the motherboard with sufficient strength, or the connection state of each boss, etc. become unstable, or become less reliable

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