Circuit board and structure using the same

1. A circuit board comprising:

an insulating layer comprising a resin; and

a conductive layer disposed over the insulating layer, the conductive layer comprising

a metal carbide layer being in contact with the insulating layer and comprising a metal carbide comprising a carbon and a first metal, wherein the first metal is chromium;

a first metal layer being in contact with the metal carbide layer and comprising the first metal; and

a second metal layer in contact with the first metal layer and comprising a second metal different from the first metal, the second metal being selected from the group consisting of copper, gold, silver, platinum and aluminum, wherein the second metal layer is connected to the metal carbide layer via the first metal layer.

2. The circuit board according to claim 1 , wherein the resin has neither glass-transition temperature nor melting point.

3. The circuit board according to claim 1 , further comprising:

a plurality of insulating layers;

wherein the conductive layer is on a top layer of the insulating layers.

4. A structure comprising:

a circuit board according to claim 1 ; and

an electronic device mounted over the circuit board and electrically connected to the conductive layer.

5. The circuit board according to claim 1 , further comprising:

a via conductor in a via hole in the insulating layer, the via conductor comprising:

an extended portion of the metal carbide layer bonded to an inner wall of the via hole,

an extended portion of the first metal layer bonded to the extended portion of the metal carbide layer,

an extended portion of the second metal layer bonded to the extended portion of the first metal layer.

6. The circuit board according to claim 1 , wherein a thickness of the first metal layer is larger than a thickness of the metal carbide layer.