| 摘要 |
PURPOSE:To prevent the portion lying under a ball-bonded section from being damaged, by cooling gradually the Cu ball after the melted Cu ball is formed, in order to enlarge the crystal grain size of the ball, in the case where Cu- bonding is done. CONSTITUTION:Using a wire-bonder, a pad section of a pellet 8 on an island 7 of a lead frame and a lead section 9 of the lead frame are connected. In the case where Cu wire 2 is ball-bonded to the pad section of the pellet 8, a molten Cu ball 2' is formed at the tip of the wire 2 and is gradually cooled, and then ball bonding of the wire 2 is done. At this time, the crystal grain size of the ball 2' may be enlarged and the hardness of the ball 2' may be relaxed. In this way, damage of the pellet 8 can be avoided. |
