| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent the deterioration of the connection reliability of solder by preventing the progress of oxidation on the surface of the solder. SOLUTION: When a semiconductor integrated circuit element 5, the semiconductor circuit element of which is mounted on a first substrate 3 is mounted of the second substrate 2 of the whole device 5, the upper and lower projections 13 and 12 of a first substrate 1 are respectively welded to a solder 14. The upper projection 13 is welded to the circuit device 5 via the solder 14 and the lower projection 12 is welded to the second substrate 2 via the solder 14. Since the upper projection 13 is welded by locally heating the projection 13, the heat energy produced when the projection 13 is heated is not transferred to the lower projection 12. Therefore, the lower projection 12 is not oxidized, and welding reliability will not deteriorate chemically. The welding reliability will not deteriorate physically also, because the projections 12 and 13 turn into a flexible structure, when the projections 12 and 13 heated due to a glue-like material held between the projections 12 and 13 and the projections 12 and 13, and the lower projection 12 is welded uniformly to the second substrate 2 and will not cause dimensional variation, when the projection 12 is welded to the second substrate 2.</p> |
