A semiconductor device, comprising: a semiconductor substrate; an integrated circuit structure formed on said semiconductor substrate; and a multi-layer wiring structure formed above said integrated circuit structure; wherein said multi-layer wiring structure comprises: a lower wiring structure; an interlayer insulating film covering said lower wiring structure; a wiring trench located in said interlayer insulating film from an upper surface thereof, and a via hole passing through said interlayer insulating film from a lower surface of said wiring trench in an inner area thereof and reaching said lower wiring structure, said via hole having a diameter smaller than a width of said wiring trench; said multi-layer wiring structure being characterised by an insulating pillar pattern projecting upward from the lower surface of said wiring trench in an area outside of said via hole, the insulating pillar pattern being made of a same material as said interlayer insulating film, wherein said insulating pillar pattern is provided in a first area of said wiring trench near said via hole and is absent in a second area of said wiring trench remote from said via hole; and a dual damascene copper or copper alloy wiring filling said wiring trench and said via hole. a semiconductor substrate; an integrated circuit structure formed on said semiconductor substrate; and a multi-layer wiring structure formed above said integrated circuit structure; wherein said multi-layer wiring structure comprises: a lower wiring structure; an interlayer insulating film covering said lower wiring structure; a wiring trench located in said interlayer insulating film from an upper surface thereof, and a via hole passing through said interlayer insulating film from a lower surface of said wiring trench in an inner area thereof and reaching said lower wiring structure, said via hole having a diameter smaller than a width of said wiring trench; said multi-layer wiring structure being characterised by an insulating pillar pattern projecting upward from the lower surface of said wiring trench in an area outside of said via hole, the insulating pillar pattern being made of a same material as said interlayer insulating film, wherein said insulating pillar pattern is provided in a first area of said wiring trench near said via hole and is absent in a second area of said wiring trench remote from said via hole; and a dual damascene copper or copper alloy wiring filling said wiring trench and said via hole. a lower wiring structure; an interlayer insulating film covering said lower wiring structure; a wiring trench located in said interlayer insulating film from an upper surface thereof, and a via hole passing through said interlayer insulating film from a lower surface of said wiring trench in an inner area thereof and reaching said lower wiring structure, said via hole having a diameter smaller than a width of said wiring trench; said multi-layer wiring structure being characterised by an insulating pillar pattern projecting upward from the lower surface of said wiring trench in an area outside of said via hole, the insulating pillar pattern being made of a same material as said interlayer insulating film, wherein said insulating pillar pattern is provided in a first area of said wiring trench near said via hole and is absent in a second area of said wiring trench remote from said via hole; and a dual damascene copper or copper alloy wiring filling said wiring trench and said via hole.