PURPOSE: To form a solder bump in high bump height directly without shaping a foundation metal onto an electrode, and to obtain a method, through which a process can be simplified, by bringing molten solder containing aluminum into contact with an electrode section and applying ultrasonic waves to molten solder.
CONSTITUTION: An electrode 33 is exposed from an insulating film 34 coating a substrate 31, molten solder 23 containing aluminum is brought into contact with at least the electrode section 33 and ultrasonic waves are applied to the molten solder, and a natural oxide film on the surface of the electrode 33 is broken while a solder layer 35 is attached selectively through alloying with the electrode 33. An ultrasonic soldering device shown in the figure is used, high-temperature solder of 95Zn-Al is employed as solder, a double-sided adhesive tape for a high temperature is stuck onto the rear of an silicon wafer 11 to which the electrode 33 consisting of Al-2%Si-2%Cu is shaped, and the silicon wafer 11 is arranged lengthwise under the state in which it is bonded with a glass plate, and dipped into ejected molten solder 23. An ultrasonic vibrator 25 is inserted into molten solder 23 in the vicinity of the silicon wafer 11, and ultrasonic waves are applied to molten solder 23.
IWASE NOBUO
SAITO KAZUYOSHI
HIRATA SEIICHI
