Integrated circuit package with thermal path layers incorporating staggered thermal vias

A package for an integrated circuit comprising:

• a plurality of cavity-defining layers of thermally and electrically insulating material with conductive strips and vias applied on and through at least some of said cavity-defining layers providing for the conduction of electrical signals, said layers including apertures so that each of said plurality of cavity-defining layers includes at least one aperture, said apertures collectively defining a die cavity;
• a thermally and electrically conductive heat spreader for conducting heat from said die cavity;
• and
• a thermally conductive electrical barrier between said plurality of layers and said heat spreader, said barrier including at least first and second layers primarily of electrically insulating material, said first and second layers being in contact, said first layer including a first pattern of thermally conductive vias extending therethrough, said second layer including a second pattern of thermally conductive vias extending therethrough, said first and second patterns being staggered so that the vias of said first and second layers define an electrically insulating thermal path between said die cavity and said heat spreader.