To make the surface of an insulation film, forming a resist layer for forming a wiring trench, hydrophobic in a dual damascene method in order to improve adhesion tightness and avoid the separation of the resist layer.

A lower layer wiring layer 6 comprising a barrier metal layer 4 and a metal wiring layer 5 is formed in a lower layer wiring trench 3 formed in a lower layer insulation film 2 on a semiconductor substrate 1. Then, after a protective insulation film 7 and an upper layer insulation film 8 are formed on the substrate, a contact hole 8a is formed in the upper layer insulation film 8. Then, the surface of the upper layer insulation film 8 is washed by an amine- system chemical solution. Then, the surface is washed by deionized water for ten minutes or longer to remove the amine-system chemical solution. Then, the upper layer insulation film 8 is etched by a resist layer 12 having an opening 12a including the contact hole 8a as a mask to form an upper layer wiring trench 8b connected with the contact hole 8a. Then, an upper layer wiring layer 15 comprising a barrier metal layer 13 and a metal wiring layer 14 is formed.