
Ion Trapping Agents for Semiconductor Packaging: Controlling Ionic Impurities in Epoxy Encapsulants
Introduction As semiconductor packages become smaller, denser, and more highly integrated, material purity becomes increasingly important to long-term device reliability. Epoxy molding compounds (EMCs), liquid encapsulants, underfills, adhesives, and other polymeric packaging materials protect semiconductor devices from mechanical stress and environmental exposure. However, these materials can also contain trace ionic impurities originating from raw materials, synthesis residues, additives, fillers, processing steps, or external contamination. Among these impurities, mobile ions such as chloride (Cl⁻), sodium (Na⁺), potassium (K⁺), and other ionic species can become problematic when moisture, electrical bias, and elevated temperature are present. Research on microelectronic encapsulants has shown that