| 摘要 |
PROBLEM TO BE SOLVED: To prevent the occurrence of voids when a soldering section between a BGA(ball grid array) and a printed wiring board is filled with an insulating resin. SOLUTION: On the lower surface of a BGA or FPBGA(ball grid array or fine-pitch ball grid array), four grooves 1 are arranged in a grid-like state. Each groove 1 is formed between arrays of bumps 2 and the width and depth of the groove 1 are adjusted so that the groove 1 may not deteriorate the function of the BGA or FPBGA. At the time of injecting an insulating resin 8 into a soldering section, the resin 8 is injected from a certain side of the BGA or FPBGA. Of the injected resin 8, the part which gets in the grooves 1 flows in the grooves 1 as shown by the arrows A prior to the part which gets in the other section than the grooves 1 due to a capillary action and the part which gets in the other section than the grooves 1 flows in the directions shown by the arrows B and spreads around the bumps 2. |
