Light Enhanced Cu to Cu Bonding with Different Electromagnetic Radiations

An innovative and efficient surface modification pre-treatment that enhances Cu-to-Cu direct bonding through electromagnetic irradiation, including pulsed Xenon flash and near infrared rays is proposed. Without vacuum, short but critical electromagnetic radiation exposure on faying faces prior to bonding can significantly improve the joint strength up to 50% or even more. Copper atom diffusion acceleration by increased compressive residual surface stresses resulting from sudden heating/cooling accounts for the joint reinforcement.