Method and device for making a metal bump with an increased height

A device for making metal bumps includes a hard conical tubular member having a vertical passage which is conical in shape and has a larger diameter at a bottom such that a lower portion of the vertical passage is larger than an upper portion of the vertical passage, whereby a metal wire is inserted into the vertical passage of the hard conical tubular member, with a lower end of the metal wire protruded downwardly out of the vertical passage, the lower end of the metal wire is melted to form a ball, the hard conical tubular member is approached to a raised platform formed on a top of a chip, and a load is applied to the metal wire and the metal wire is heated and bonded on the pad of die and ultrasonic energy is applied to deform the melted metal so as to fill up the lower portion of the vertical passage thereby forming a metal bump on the raised platform of the chip, and finally the hard conical tubular member is removed to pull off the necking position between the metal wire and a top of the metal bump thereby leaving the metal bump on the raised platform of the chip.