Method for manufacturing flexible metal-clad laminated plate

A method for manufacturing a flexible metal-clad laminated plate, the method comprising steps of:

• (a) obtaining a laminated body by laminating a polyimide resin film including a non- thermoplastic polyimide layer and an adhesive layer containing thermoplastic polyimide, the adhesive layer being provided on at least one side of the non-thermoplastic polyimide layer, and a metal foil, wherein a linear expansion coefficient of the non-thermoplastic polyimide is in a range of 20 ppm or less, and a linear expansion coefficient of the thermoplastic polyimide is in a range of 20 ppm to 100 ppm;
• and
• (b) subjecting the laminated body obtained in the step (a) to heat treatment under an inert gas atmosphere and a pressure of 0.20 to 0.98 MPa at a temperature of a glass transition temperature Tg of the thermoplastic polyimide−20° C. to the glass transition temperature Tg+50° C.