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

Abstract

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.

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