| 摘要 |
PURPOSE:To prevent occurrence of a crack in the lower side of a bonding pad part even when a thermal stress of a temperature cycle or the like is applied thereto, by a method wherein, in a first fore-end part wherein a bonding pad and an alloy are formed and connected together electrically, the ratio between the thickness of the first fore-end part and the width of the alloy therein are made to be a prescribed one. CONSTITUTION:To a ball-shaped bonding part 5' of a wire 5 for a connector on a bonding pad part 6 of a pellet 4, a shearing force due to shrinkage of molding resin is applied from the direction of the outside of the pellet toward the center thereof. Since this shearing force presses an Au ball 5', a moment is caused, a tensile stress is generated in the end part of the Au ball, and a crack occurs when the tensile stress exceeds a breaking strength of the pellet. When the thickness of the Au ball is made small by a mechanism, a pressed area (sectional area) of the Au ball decreases and therefore the stress diminishes, thus causing no crack. When an area of junction formed by an Au-Al alloy 10 is widened, likewise, a concentrated stress applied to the end of the Au ball diminishes and therefore the occurrence of a crack 14 can be prevented. In the relationship between the thickness (d) of the Au ball and the width l of the Au-Al alloy on a pad in the area of junction, in particular, the occurrence of the crack can be prevented most effectively when the d/l ratio is 0.2 or below. |
