A heat conductive substrate (50) is mounted within a through-opening (60) of a printed circuit board (52). An integrated circuit (42) then is mounted to one side of the heat conductive substrate, while a heat sink (90) is fixed in thermal contact to the other side of the substrate. There is no direct thermal contact between the IC and the PC board. The heat conductive substrate is mounted to the PC board by applying a controlled pressure to normal surfaces of multiple portions (71) of the substrate. Such pressure reducing the thickness and expands the area of the pressed portions locking the substrate to the PC board. An air gap (75) occurs between the substrate and the PC board everywhere except for the pressed regions of the substrate. Such pressed regions occur along the periphery (67) of the substrate.