Flexible copper clad laminate

A flexible copper clad laminate comprising a copper foil on at least one surface of a polyimide resin laminate,

• wherein the copper foil has a surface-treated layer containing an Ni—Zn alloy on the at least one surface of an original copper foil (untreated copper foil) contacting the polyimide resin laminate, the ratio of the amount of Zn with respect to the total of Ni and Zn in the surface-treated layer is 6 wt % or more and 15 wt % or less, and the amount of Ni is 0.45 to 3 mg/dm2 and the amount of Zn is 0.08 mg/dm2 or more,
• wherein the polyimide resin laminate comprises a polyimide resin layer having a coefficient of linear thermal expansion of 1×10−6[1/K] or more and 30×10−6[1/K] or less, and a thermoplastic polyimide resin layer having a coefficient of linear thermal expansion of exceeding 30×10−6[1/K] and 60×10−6[1/K] or less, and
• wherein the thermoplastic polyimide resin layer is bonded to the copper foil.