| 摘要 |
A silicon nitride circuit board comprises a silicon nitride substrate having oxide layers at surfaces thereof, and copper system circuit plates directly bonded to the silicon nitride substrate thorough the oxide layer by the use of the DBC (copper directly bonding) method. The oxide layer disposed on the surface of the silicon nitride substrate consists essentially of an aluminum oxide layer. This aluminum oxide layer is formed by the process of coating/calcinating a super fine grain alumina sol. The aluminum oxide layer is dense and stable compared with an Si-O system oxide layer which is formed on the silicon nitride substrate by the use of the thermal oxidization method. In particular, the aluminum oxide layer formed by the process of coating/calcinating the super fine grain alumina sol is superior in interface bonding ability with the silicon nitride substrate. Therefore, when the copper system circuit plate is bonded to the silicon nitride substrate by the use of the DBC method, the poor bonding and the blistering can be controlled to be generated, and then the thermal resistance due to the oxide layer can be controlled to be increased. <IMAGE> |
