[INNER LAYER STRUCTURE OF A CIRCUIT BOARD]

摘要

The present invention provides an inner layer structure of a circuit board. The inner layer structure of the present invention uses column-shaped or conned-shaped bumps to replace the conventional PTH process, and uses the bumps as media to electrically connect two adjacent patterned conducting layers. Hence, inner layer structure of the present invention can effectively simplify the layout design and the fabrication complexity, and increase the layout density of the circuit board.