Study on the influencing factors of peeling strength of aluminum nitride DBC substrates

Aluminum nitride direct bonded copper (DBC) substrates were fabricated by direct bonding of copper and aluminum nitride under high temperature. Combined with the high current carrying capability of copper and the good insulation property of ceramic substrates, aluminum nitride DBC substrates had high thermal conductivity and electrical insulation, high current capacity, excellent mechanical strength and so on. The substrates were widely applied to power electronics field, such as smart grid, motor car and automotive electronics. In this paper, influencing factors of peeling strength in the production process were discussed. The dense oxide layer was formed on the surface of aluminum nitride in the 1150 °C under oxygen atmosphere. Oxidizing oxygen-free copper by high-temperature oxidation method helped to reduce interface cavity and improve the bonding strength of the copper and aluminum nitride. When the calcination conditions of direct bonded copper were 1068 °C and 600ppm of oxygen content, the peeling strength of the substrates could be reach 75N/cm.