| 摘要 |
PURPOSE:To make a high-cost evaporation apparatus unnecessary and to reduce a cost for an apparatus and a running cost sharply by immersing a silicon wafer whose provisional soldering operation has been completed in an organic liquid which has been heated at a temperature of higher than the melting point of a solder. CONSTITUTION:A solder 9 of a definite amount is attached provisionally to an aluminum electrode pad 8 by using an ultrasonic wire bonder. The large part of an oxide film 8A on the surface of aluminum of the pad 8 is left, but one part of the oxide film 8A is broken due to ultrasonic energy; the solder 9 and the pad 8 are bonded and fixed provisionally in the broken part. After a flux has been supplied to the pad 8 on a wafer 1, the wafer 1 is immersed in an organic liquid 10 which has been heated at a temperature of higher than the melting point of the solder 9. Then, a spherical solder bump electrode 11 whose height is stable at 50-150mum is formed on the pad 8. By this setup, a high-cost evaporation apparatus is made unnecessary; a cost for an apparatus and a running cost can be reduced sharply. |
