An Innovative Hybrid Cleaning Approach for Contaminant Removal in Semiconductor Packaging

Delamination poses a significant challenge in semiconductor industry, particularly in electric vehicle (EV) components, impacting their performance and reliability. It occurs when the adhesion between the encapsulation material and the leadframe fails, often due to thermal stress. Roughened leadframes have been adopted to enhance their interlocking among them. However, this approach inadvertently introduces surface contamination during flux cleaning, which can compromise wire bonding quality. The presence of such contamination underscores the need for more sophisticated cleaning methods. This study investigates a hybrid cleaning solution designed to reduce surface contamination on roughened leadframes. Conventional immersion-type cleaning has shown limitations in effectively addressing this issue. Therefore, a hybrid method combining immersion-type flux cleaning with subsequent spray-in-air cleaning process using deionized (DI) water is proposed. This dual approach leverages the advantages of both immersion and high-pressure DI water spray, improving cleaning efficiency and minimizing contamination. Extensive testing under various conditions has demonstrated a marked reduction in surface contamination compared to conventional methods, significantly lowering the risk of defects such as non-stick on lead (NSOL) or non-stick on pad (NSOP). The paper discusses the mechanism behind this hybrid cleaning approach, offering a pathway forward for optimizing flux cleaning on roughened leadframes and enhancing overall wire bonding reliability.