| 摘要 |
PROBLEM TO BE SOLVED: To make the forms and the heights of solder bumps to be uniform by executing solder printing through the use of a solder printing mask where the opening area of through holes is changed in accordance with via-on/off and the holes are arranged. SOLUTION: Through holes 22A and 22B for filling solder paste are formed on the opening of a solder resist layer in a solder printing mask 20. The through holes 22A are those (via-on holes) for forming solder bumps on via holes. On the other hand, through holes 22B are those (via-off holes) for forming the solder bumps on a smooth conductor circuit. The diameters of the through holes 22A on the mask of via-on are made to be larger than those on the mask of via-off. Thus, the filling quantify of solder paste into the via holes increases, therefore inconvenience in the forming of the solder bumps owing to non-filling to the via holes and a filling lack after printing is eliminated, and the heights of the solder bumps can be made uniform. |
