| 摘要 |
PURPOSE: To prevent breakages, without generating clearances between an electrode and a solder bump and improve the productivity by providing a curvature on the tip end of a solder bump formed on a substrate and flattening a joint surface between the solder bump and substrate. CONSTITUTION: In a bump transfer substrate 11, a solder bump 12 is formed on a base material 13 by forming successively a curvature part 12d on a columnar part 12c, and a curvature is formed on the tip end 12a of the curvature part 12d. The tip end 12a is a plane, having a curvature of the tip end of the curvature part 12d, and the solder bump 12 is provided with the columnar part 12c, whose bottom is flat and which is placed on the one main surface 13a of the base material 13. When the solder bump 12 is transferred to an electrode on a semiconductor element using the bump transfer substrate 11, the electrode and solder bump 12 can be joined with each other without generating a clearance therebetween, even if a recessed part is formed in an insulating film and the electrode on the semiconductor element because the tip end 12a of the solder bump 12 has a curvature. Thus, voids can be eliminated, and the productivity be improved. |
