Copper-clad laminate, wiring board, and copper foil with resin

A copper foil with resin comprising:

• a resin layer;
• and
• a copper foil existing to be in contact with at least one surface of the resin layer, the copper foil having a layer treated with a silane coupling agent having an amino group in the molecule as a silane coupling agent layer,
• wherein the resin layer contains a resin composition containing a polymer having a structural unit represented by the following Formula (1) in a molecule or a semi-cured product of the resin composition,
• a chromium element amount, on an exposed surface on which the cured resin layer is exposed by an etching treatment of the copper foil existing to be in contact with a surface of the cured resin layer with a copper chloride solution when the resin layer provided in the copper foil with resin is cured, measured by X-ray photoelectron spectroscopy is 7.5 at % or less with respect to a total element amount measured by X-ray photoelectron spectroscopy, and
• a surface roughness of the exposed surface is 1.1 um or less in terms of ten-point average roughness , and
• wherein a thickness of the silane coupling agent layer is sufficient to cause a nitrogen element amount, on the exposed surface, measured by X-ray photoelectron spectroscopy to be 1.0 at % to 5.0 at % with respect to a total element amount measured by X-ray photoelectron spectroscopy:
• wherein in Formula (1), Z represents an arylene group, R1 to R3 each independently represent a hydrogen atom or an alkyl group, and R4 to R6 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.