| 摘要 |
PROBLEM TO BE SOLVED: To provide a multilayer substrate in which build-up layers are laminated on both surface of a core layer having a through hole via, and which reduces a stress occurring due to a difference between linear expansion coefficients of a filling resin and a surrounding component in the through hole via to inhibit damage on the substrate.SOLUTION: A multilayer substrate comprises: a core layer 20 composed of an electrical insulating resin; a surface side build-up layer 30 which is arranged on a surface 20a of the core layer 20 and on which surface wiring 61-63 is formed; a rear face side build-up layer 40 which is arranged on a rear face of the core layer 20 and on which rear face wiring 71, 72 is formed; a through hole 81a which is provided in the core layer 20 and pierces the core layer 20; a Cu conductor film 81b formed on an internal surface of the through hole 81a; and a through hole via 81 composed of an electrical insulating filling resin 81c filling the through hole 81a. In a substrate thickness direction, a linear expansion coefficient α3 of the filling resin 81c is closer to a linear expansion coefficient α2 of the Cu conductor film 81b than a linear expansion coefficient α1 of the resin which composes the core layer 20. |
