MANUFACTURING METHOD OF COMPONENT BUILT-IN SUBSTRATE

To uniformize a resin thickness in an inter-layer insulation layer on a core substrate.SOLUTION: A manufacturing method of an electron component built-in substrate, includes steps of: preparing a core substrate which has a first surface and a second surface opposite to the first surface, and is provided with a penetration hole; arranging an electronic component in the penetration hole; preparing a prepreg which is formed by impregnating a resin into a core material and of which a thickness from a fourth surface to the core material is larger than a thickness from a third surface to the core material; laminating the prepreg onto the core substrate in a direction where the fourth surface becomes a first surface side of the core substrate; and forming an inter-layer insulation layer by compressing and heating the prepreg. At the time of compression and heating of the prepreg, the resin contained in the prepreg is filled in a gap between a sidewall of the penetration hall and the electronic component, and thereby a difference between the thickness of the prepreg from the fourth surface to the core material and the thickness from the third surface to the core material on the first surface of the core substrate becomes smaller than a difference between the thickness from the fourth surface to the core material and the thickness from the third surface to the core material on the prepreg before the lamination.SELECTED DRAWING: Figure 1J 【課題】コア基板上の層間絶縁層における樹脂厚みの均一化【解決手段】電子部品内蔵基板の製造方法は、第１面とその反対の第２面を有し貫通孔が形成されたコア基板を準備することと、貫通孔内に電子部品を配置することと、芯材に樹脂を含浸させてなり、第４面から芯材までの厚みが第３面から芯材までの厚みよりも大きなプリプレグを準備することと、プリプレグを、その第４面がコア基板の第１面側となる向きで、コア基板上に積層することと、プリプレグを加圧および加熱することで層間絶縁層を形成することと、を含み、プリプレグの加圧および加熱時に、プリプレグに含まれる樹脂を貫通孔の側壁と電子部品との隙間に充填させることで、コア基板の第１面上でのプリプレグの第４面から芯材までの厚みと第３面から芯材までの厚みとの差を、積層前のプリプレグにおける第４面から芯材までの厚みと第３面から芯材までの厚みとの差よりも小さくすることを含む。【選択図】図１Ｊ