Direct Bonded Copper

Direct bonded copper (DBC) substrates consist of a ceramic isolator, Al₂O₃ (aluminium oxide) or AlN (aluminium nitride), onto which pure copper is bonded in a high temperature melting and diffusion process.

The great heat conductivity of Al₂O₃ (24 W/mK) and AlN (130 to 180 W/mK) as well as the high heat capacity and spread of the thick copper coating (200 - 600 µm) make DBC substrates irreplaceable in power electronics.

The mechanical wear of the usually uncased silicon chips is low, since their thermal expansion coefficient of 7.1 ppm/K for Al₂O₃ and 4.1 ppm/K for AlN is much closer to that of silicon (4 ppm/K) than that of substrates on a metal or plastics basis.

Due to the use of pure copper, ampacity is unbeatable compared to alternative technologies. Similar to PCBs, layout may be customised.