Circuit substrate and method for manufacturing the same

A method for manufacturing a circuit substrate, comprising:

• forming a core substrate such that the core substrate has a cavity penetrating through the core substrate and an intracavity projection structure projecting from at least one side surface of the cavity;
• accommodating a plurality of metal blocks in the cavity of the core substrate such that the intracavity projection structure is positioned between the metal blocks and separating the metal blocks from contacting each other in the cavity of the core substrate;
• forming a first build-up layer comprising an insulating resin layer on a first side of the core substrate such that the insulating resin layer covers the cavity of the core substrate;
• forming a second build-up layer comprising an insulating resin layer on a second side of the core substrate such that the insulating resin layer covers the cavity of the core substrate;
• and
• filling a filling resin into a gap formed between the cavity and the metal blocks such that the plurality of metal blocks is positioned in the cavity of the core substrate,
• wherein the forming of the first build-up layer comprises forming a plurality of first conductors connected to the plurality of metal blocks, respectively, such that each of the first conductors conducts one of electricity and heat, and the forming of the second build-up layer comprises forming a plurality of second conductors connected to the plurality of metal blocks, respectively, such that each of the second conductors conducts one of electricity and heat.