| 摘要 |
<p>PURPOSE: To increase the wiring density by aligning the position for forming solder bump with the position of via hole thereby shortening the wiring length. CONSTITUTION: The position for forming a solder bump 1 is aligned with the position of via hole 5. More specifically, the solder bump 1 fills the via hole 5 made in the mounting surface and covers directly above the via hole 5. Since additional wiring from the via hole 5 is not required for the pad forming the solder bump, the wiring length can be shortened and the wiring density can be increased. Furthermore, the opening diameter X of solder resist 4 can be set larger than the opening diameter Y of via hole 5 when such structure is employed. Consequently, the requirements of the resist 4, e.g. resolution, an film thickness, are relaxed and the selection width of the solder resist 4 is widened.</p> |
