| 摘要 |
PURPOSE:To improve the joint strength of a bump and to prevent the bump from rolling easily by using the bump consisting of a non-spherical core material made of a high-melting-point material and the coating material of the core material made of a low-melting-point material for joint two substrates. CONSTITUTION:A material with a diameter of for example, 0.1-1.0mm consisting of a high-melting-point material is used for a core material A, a low-melting- point material is used for a coating material 2A, and a thin wire with the core material for bump is cut into a desired length and is used as a bump. Namely, the thin wire with the core material for bump is passed into the opening of a capillary 7, the thin wire is led out of the opening edge of the capillary 7 by a required length, the tip of the thin wire is aligned onto a pad 3, and then a spark voltage is applied for melting. Then, the tip is pressed against the pad 3 on the printed circuit board 4 and ultrasonic vibration is given to the thin wire for contact bonding. Then, cutting is made at a desired height above the pad 3 with a clamp and the bump is aligned to the pad 5 of the printed circuit board 6 before reflow. |
