High-Speed Laser Plating for Wire-Bonding Pad Formation

Abstract

The present paper proposes high-speed laser plating for forming wire-bonding pads on a Cu leadframe using Ag nanoparticles. The novelty of the process lies in the implementation of drop-on-demand laser plating on the specially designed leadframe. Various aspects of the proposed method are investigated, including experimental set-up, multistep ink-jet printing, laser-plating parameters, quality of the sintered film, and wire bondability. It is found that both the quality of the sintered Ag pad and wire bondability are comparable to those of an electroplated Ag film when the near-infrared CW laser irradiates the pad for a short time of milliseconds. The superiority of the high-speed laser plating is confirmed from the viewpoints of material consumption, the necessity of pre- and post-processing, thermal damage to the pad and substrate, and environmental protection.