Abstract
The present study aims to develop a method of forming a functional film for wire bonding by using dry laser plating. The paste containing 82 mass% Ag (100 nm in average diameter) was coated on a Cu lead-frame by a spin coater. After being sintered with an Nd:YAG laser (1064 nm in wavelength), the paste became a bulk structure with a thickness of 3 μm. When a ・25 ・m Au wire was bonded on the pad, average pull strength of 7.4 cN was obtained. This value is similar to that of an electroplated Ag film. However, excessive laser power promotes the diffusion of Cu to the Ag film, resulting in poor wire bondability.
