A Comparative Study on Various Au Wire Rinse Compositions and Their Effects on the Electronic Flame-Off Errors of Wire-Bonding Semiconductor Package

In this study, we identify the origin of electronic flame-off (EFO) errors based on the type of rinse applied for the surface treatment of gold (Au) wires in the wire-bonding semiconductor packaging process. Hydrocarbon and silicone surfactants are commonly used for Au wire surface treatment, and five different 1.0 wt% rinse solutions with varying compositions are applied to the Au wire surface. To determine the origin of EFO errors, an experiment is conducted to examine the reactivity of the rinse-coated Au wires with silicon (Si)-containing dust, which is inevitably generated in the wire-bonding process. Optical microscopy and field-emission scanning electron microscopy show that a large amount of dust is adsorbed onto the surface of the Au wire coated with a Si-containing rinse. This is attributed to the Si component in the rinse, which interacts with the electric arc during the EFO process. Si-CH3 bonds break at a high thermal energy, thereby enabling the formation of low-activation-energy nonpolar <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sigma $ </tex-math></inline-formula> bonds with Si-containing dust. As these defects negatively impact productivity and reliability, we suggest using Si-free organic rinses for Au wire surface treatment in the wire-bonding process to reduce the defect rates associated with contamination.