| 摘要 |
PROBLEM TO BE SOLVED: To form a gap between an electronic component and a substrate without using an electronic component and a substrate with a complicated constitution and without requiring a complicated production process. SOLUTION: In this invention, using solder paste in which an Sn-Bi-based powder alloy 11 obtained by making an Sn-Bi-based alloy into a powdery shape as a first metal and Cu powder 12 obtained by making Cu having a melting point higher than that of the Sn-Bi-based alloy into a powdery shape as a solder material mixed in a flux, the component electrode 23 in a leadless component 20 and the component connection land 6 in a printed circuit board 5 are thermally welded at a heating temperature higher than the melting point of the Sn-Bi-based alloy and lower than the melting point of the Cu powder, thus the component electrode 23 in the leadless component 20 lies on the Cu powder 12 remaining as solid without being dissolved, and a gap corresponding to the diameter of the Cu powder 12 can be formed. COPYRIGHT: (C)2008,JPO&INPIT |
