| 摘要 |
PURPOSE:To prevent the short circuit between an IC and the edge of a solder and to alleviate stress due to difference in thermal expansions between a substrate and the IC, by making a basis metal layer, which is included in a solder bump, thick, and reducing the volume of the solder in one bump. CONSTITUTION:An IC 3 with a solder bump is bonded to a resin circuit substrate 6 having a conducting pattern 7 with a face down attitude. At this time, the thickness of the core 1 of a basis metal such as copper, which is included in the solder bump 2, is made to be 20-35mum. Then, at the time of bonding, the solder layer of several tens of mum remains between the core 1 of the metal and the conducting pattern immediately beneath the bump. After the bonding, the solder is solidified. Then the short circuit between the IC 3 and the edge of the solder is prevented. The stress due to the difference in thermal expansions between the substrate 6 and the IC 3 is alleviated. |
