Direct Bond Copper (DBC) on Ceramic Used for Power Circuits

DBC involves diffusion bonding highly conductive copper foils directly to ceramic substrates, and is especially useful for manufacturing hybrid circuits and packages with high power-handling capability.

Chemically etched direct bond copper (DBC) substrates are commonly used in power modules, because of their very good thermal conductivity. They are composed of a ceramic tile (commonly alumina–aluminum oxide) with a sheet of copper bonded to one or both sides by a high-temperature oxidation process. Circuit patterns can be photoetched on both sides to form an electrical circuit.

One of the main advantages of photo etched DBC substrates is their low coefficient of thermal expansion, which is close to that of silicon (compared to pure copper). This ensures good thermal cycling performances (up to 50,000 cycles). The DBC substrates also have excellent electrical insulation and good heat spreading characteristics.

Photo etching is the fastest and easiest method of fabricating DBC circuits. The ability to carry far higher power loads than conventional “microelectronics” and the built-in heatsink effect of the ceramic makes etched DBC the material of choice for many power and RF/microwave applications.