A bump connection is formed by stacking at least two metallic balls of different kinds of metals on a conductor of an electronic component such as a semiconductor device. The bump connection is obtained by forming the metallic balls using metallic wires. An apparatus for forming the connection includes a support, capillary member for having a wire pass therethrough, a pair of clamps for clamping the wire, and a nulltorchnull (e.g., electrode, gas flame) which heats the tip of the wire, forming the ball. Successive balls can be formed by this apparatus atop the initially formed ball to provide a stacked configuration.