Patent ID: 7574793

Claim:
A process of forming a circuit board assembly, the process comprising the steps of: providing green tapes of which at least a first plurality thereof consist essentially of low thermal conductivity, electrically-nonconductive materials in a binder and of which at least a second plurality thereof contains thermally-conductive particles dispersed in a matrix comprising electrically-nonconductive materials and a binder, the thermally-conductive particles having a higher coefficient of thermal conductivity than the electrically-nonconductive materials of the green tapes; forming vias through at least some of the first plurality of the green tapes; depositing an electrically-conductive material within the vias and depositing an electrically-conductive material on surfaces of the first plurality of the green tapes; collating and laminating the green tapes together to form a green substrate; co-firing the green substrate to form a co-fired substrate comprising at least first and second regions superimposed and bonded to each other, the first region comprising first ceramic layers that are superimposed and formed by the first plurality of the green tapes, the second region comprising a second ceramic layer formed by the second green tape, at least some of the first ceramic layers of the first region being bonded to each other, the electrically-conductive material on the surfaces of the first plurality of the green tapes forming conductor lines between adjacent pairs of the first ceramic layers, the vias filled with the electrically-conductive material forming electrically-conductive vias that electrically interconnect the conductor lines on the first ceramic layers; and then mounting a surface-mount integrated circuit (IC) device to a first surface of the substrate defined by one of the first ceramic layers.