An electronic circuit component having particular utility in multi-layer circuit board construction formed essentially of a flexible dielectric sheet of material used as the board base to which is attached circuit runs etched from copper sheets clad to the dielectric sheet prior to etching. Generally, circuitry runs are separated according to alignment with either the X or Y axis with the runs on each side of the dielectric sheet being parallel to only one of those axes. Integration of communication between X and Y runs is by means of plated through holes to which circuit elements may be attached. Flatpack integrated circuits are attached to the board oriented with their covers toward and their heat sink base portions away from the board. By placing all flatpacks on one side of the flexible board structure and looping the structure back on itself, a high circuit component density can be achieved with the heat sink portions of flatpacks exposed exteriorly of the loops of the structure facilitating placing the flatpacks in heat conducting contact with a casing.