摘要 |
Methods for controlling thermal conductivity paths in a metal core circuit board, as well as methods to provide selective electrical isolation, are described. In one embodiment, grooves are formed in an aluminum substrate surrounding areas where electrical components are to be mounted on the substrate. The grooves are oxidized along with the opposing surface of the substrate to create a vertical oxide ring around the area for electrical and lateral thermal isolation. This also allows the substrate to be made relatively thick for mechanical strength. Other features include forming copper around oxidized sides of the substrate for connection between top and bottom copper layers; plating up copper to be co-planar with a raised dielectric layer; forming indentions in the substrate for containing a dielectric so the dielectric is co-planar with the remaining surface; forming copper vias through the substrate; and planarizing the substrate surface so that conductors and dielectric layers are co-planar.
|