Patent ID: 7356916

Claim:
A method of manufacturing a circuit board, the method comprising: forming a board material including providing a via hole to a prepreg in stage B that has film on both faces thereof, filling the via hole with conductive material, said conductive material being constituted by conductive paste including conductive particles and a thermosetting resin component, after filling the via hole with conductive material, removing the film from both the faces of the prepreg in stage B; and heating and pressing a layered body including the board material; wherein the prepreg in stage B includes a thermosetting resin, and a reinforcing member made of fiber and having a thickness T 1 , said reinforcing member having oppositely facing surfaces, and said thermosetting resin forming resin layers on said oppositely facing surfaces of said reinforcing member; and wherein said heating and pressing of the layered body involves pressing the prepreg in stage B to a thickness T 2 by forming a flow-out-section by a flow of the thermosetting resin of the prepreg in stage B, said heating and pressing is carried out such that a thickness ratio T 2 /T 1 is maintained in a range from 1 to not more than 1.5 to prevent the conductive particles from flowing laterally along a surface of the board material.