Study on Material Properties and Copper-to-Copper Wire Bonding of Cu-Pt-Au-Pd Fine Micro-Alloyed Wires

Wire bonding is the most widely used method for encapsulation, connecting chips and external contact points by metal wires. Copper is the most common material for wire bonding. However, the poor oxidation and corrosion resistance necessitates modification such as micro-alloying and coating with precious metals. Research indicates that doping within 1 wt.% of micro-alloy can improve the tensile properties, fatigue life, oxidation resistance, and corrosion resistance of wires without affecting resistance. However, coated wires have issues such as coating peeling or element solid solution during electrification. Excessive doping will reduce thermal conductivity and increase resistance. During chlorination, coated wires suffer from galvanic corrosion and pitting, leading to severe degradation of tensile properties. In contrast, micro-alloyed wires maintain high strength and elongation. In terms of bonding, replacing aluminum substrates with copper substrates can reduce resistance by 1.130 Ω and prevent the embrittlement of joint points caused by intermetallic compound (IMC) layers. In conclusion, PAP (platinum, gold, palladium) micro-alloyed copper wire with copper substrate is a feasible alternative to traditional copper-coated wires and aluminum substrates.