Wiring substrate and method for manufacturing wiring substrate

A method for manufacturing a wiring substrate, comprising:

• forming a second resin insulating layer on a first resin insulating layer such that the second resin insulating layer is in contact with a surface of the first resin insulating layer;
• irradiating laser upon the second resin insulating layer such that a recess penetrating through the second resin insulating layer and exposing the first resin insulating layer is formed;
• and
• forming a conductor layer comprising conductor material filled in the recess formed through the second resin insulating layer such that the conductor layer is embedded in the second resin insulating layer,
• wherein the second resin insulating layer are formed on the surface of the first resin insulating layer such that the first resin insulating layer and the second resin insulating layer have different processability with respect to the laser and that an absorbance coefficient of the second resin insulating layer with respect to the laser is larger than an absorbance coefficient of the first resin insulating layer with respect to the laser, and the forming of the conductor layer includes forming a metal film layer on a surface of the second resin insulating layer in the recess and a surface of the first resin insulating layer at the bottom of the recess and forming a plating film layer on the metal film layer such that the plating film layer fills the recess.