Circuit board with aluminium tracks on alumina base - uses metallic base with alumina layer over which granular aluminium is deposited and selectively oxidised to form conductive paths

摘要

One or both of the sides of the aluminium substrate is covered by an insulating layer of aluminium oxide. On this bed are built layers of interconnections. The interconnections are made from a granular layer of aluminium (10), deposited by a plasma arc, which is selectively anodized using a mask to leave aluminium conductors (12) and alumina insulating zones (20) between the conductors. The pads for connecting components are built up by successive layers to the same level and corrected between stages to the same level. The substrate may be of aluminium or of aluminium alloy. By interconnecting electronic components on an aluminium substrate (22) the thermal conductivity and component density can be greatly improved.