Flexible contactless wire bonding structure and methodology for semiconductor device

Abstract

A semiconductor device such as a field-effect transistor, improved to reduce device resistance, comprises a leadframe which includes a die paddle integral with a first set of leads and a second set of leads that is electrically isolated from the first set, a semiconductor die having its lower surface positioned on, and electrically connected to, the die paddle, and a conductive layer on the upper surface of the die. At least one electrically conductive wire, preferably plural wires, extend laterally across the second surface of the semiconductor die, are in electrical contact with the conductive layer, and interconnect corresponding second leads on opposite sides of the die. The plural wires may be welded to leads in succession by alternate ball and wedge bonds on each lead. The conductive layer may be an aluminized layer on which is formed a thin layer a solderable material, such as tin. A solder is deposited on the tin layer, enmeshing the wires. The wires, which preferably are made of copper, then may be bonded to the electrically conductive layer by melting the solder paste, preferably by heating the leadframe, allowing the solder to reflow and wet the wires, and then cool to produce a low resistance mass between the leads.