Method of manufacturing circuit board

A method of manufacturing a circuit board, comprising:

• forming an open substrate, wherein the open substrate comprises;
• a substrate body having a top surface and a bottom surface and having a thickness;
• an opening in the substrate body, wherein the opening has a first sidewall and a second sidewall opposite to the first sidewall;
• and
• at least one first fixing portion and at least one second fixing portion extending from the substrate body toward the opening, wherein the first fixing portion and the second fixing portion are respectively protruded from the first sidewall and the second sidewall;
• recessing the first fixing portion and the second fixing portion from the top surface of the substrate body to form a cavity above remaining portions of the first fixing portion and the second fixing portion, and to make the remaining portions of the first fixing portion and the second fixing portion have heights smaller than the thickness of the substrate body;
• placing a heat dissipation block in the cavity and on upper surfaces of the remaining portions of the first fixing portion and the second fixing portion;
• and
• inserting the heat dissipation block in the opening to clamp the heat dissipation block between the first fixing portion and the second fixing portion, wherein the heat dissipation block comprises a ceramic or a composite material.