To make it possible to obtain a solder paste having a large volume by applying a copper pad as a cover on a supporting board, removing the mask material at the upper part of the copper pad, forming a hole, setting the diameter of the base part of the hole at the width smaller than the specified value corresponding to the diameter of the copper pad, and enlarging the diameter toward the opening direction.

A resist film or a polymer film is applied as a mask layer 2 on copper pad 4 covering a supporting board 1. Then, a hole 3 is formed in the mask layer 2 by laser abrasion at the upper part of the copper pad 4. The diameter of the hole 3 is made to correspond to the diameter of the copper pad 4 at the base bottom of the supporting board 1 and made to be smaller than 100μm. Furthermore, the diameter of the hole 3 at the upper side of the copper pad 4 is made larger than the copper pad 4. Then, solder paste is filled in the hole 3. Thereafter, reflowing is performed, and the mask layer 2 is removed. Thus, the solder paste having the large volume can be utilized.