Method for manufacturing a circuit board with buried element having high density pin count and the circuit board structure

A method for manufacturing a circuit board with buried high density pins, comprising:

• electroplating a carrier plate such that a first metal layer is formed on said carrier plate;
• forming a first circuit on one side surface of said first metal layer, wherein said first circuit includes a plurality of copper pads;
• covering a photoresist layer over said first metal layer and said first circuit;
• patterning said photoresist layer such that only said first circuit is covered by said photoresist layer after the patterning process;
• etching said first metal layer covered by remaining portions of said photoresist layer, thereby removing said photoresist layer entirely;
• providing an adhesive layer between some of said copper pads and a buried element in order to fix said buried element over said adhesive layer, wherein said buried element has a plurality of high density I/O (Input/Output) pins, each is aligned with a micro copper window defined between an adjacent pair of said copper pads and is staggered with a copper window defined by one of said copper pads adjacent to said micro copper window, wherein establish said copper window as a target point;
• sequentially forming an insulating layer and a second metal layer over said first circuit and said buried element and removing said carrier plate and etching said first metal layer until said adhesive layer is exposed from said first metal layer via said micro copper window while said insulating layer is exposed from said first metal layer via said copper window;
• optically aligning said target point and employing a drilling process to drill through the insulation layer between corresponding pair of said I/O pin and said micro copper window so as to form a micro through hole in alignment with said I/O pin and a through hole extending through said insulating layer and said second metal layer and in alignment with said copper window;
• electroplating to form a conduction layer which covers said micro through hole and said through hole;
• and
• etching said conduction layer in order to remove portions of said first metal layer until exposing said first circuit and simultaneously forming a plurality of micro conduction holes and a plurality of conduction holes for establishing electrical communication between said I/O pins of said buried element with said micro conduction holes and said conduction holes.