Wiring board and method for manufacturing wiring board

A method for manufacturing a wiring board, the method comprising:

• providing a substrate having a first surface and a second surface opposite to the first surface, wherein first wiring patterns and second wiring patterns are respectively disposed on the first surface and the second surface of the substrate;
• superimposing a first resin substrate containing a thermoplastic polymer on the first wiring patterns of the substrate;
• superimposing a second resin substrate on the second wiring patterns of the substrate;
• and
• heating the substrate, the first resin substrate, and the second resin substrate in a superimposed state to obtain a wiring board having the first wiring patterns and the second wiring patterns buried therein,
• wherein the first resin substrate positioned between the first wiring patterns disposed in a first in-plane direction of the same plane has an elastic modulus at a heating temperature of 140° C. in heating in the superimposed state equal to or less than 0.1 MPa in a first region to a first thickness position corresponding to a thickness of the first wiring pattern with a surface on a side superimposed on the substrate as a first starting point,
• the second resin substrate positioned between the second wiring patterns disposed in a second in-plane direction of the same plane has an elastic modulus at a heating temperature of 140° C. in heating in the superimposed state equal to or less than 0.1 MPa in a second region to a second thickness position corresponding to a thickness of the second wiring pattern with a surface on a side superimposed on the substrate as a second starting point, and
• a dielectric loss tangent of the wiring board is equal to or less than 0.006;
• wherein the first resin substrate further contains a compound having a melting point lower than a melting point of the thermoplastic polymer.