| 摘要 |
PURPOSE:To improve connection reliability of a solder plated single in-line memory module by making a fusing point of solder plating of an outside electrode not lower than a melting heating temperature of solder cream when a lead of an IC is mounted on a component package electrode. CONSTITUTION:Solder plating 5 of fusing point of 183 deg.C of 37% lead - 63% tin is applied to a thickness of 10 to 20mum by electrolytic plating on a component mount electrode 3 of a 35mum-thick copper foil printed on a printed substrate 2 of a single in-line memory module of an outside electrode and an outside electrode 4. Then, low fusing point solder cream 6 of a fusing point of 157 deg.C of 15% lead - 80% indium - 5% silver is applied to a thickness of 200mum on the solder plating 5 alone on the component mount electrode 3. A lead 7 of an IC 1 is positioned and brought into contact with low fusing point solder cream 6 and the IC 1 is mounted on the printed substrate 2. Thereafter, the low fusing solder cream 6 is heated and molten at a reflow temperature of 170 deg.C and the lead 7 is soldered to the component mount electrode 3. |
