Patent ID: 7148571

Claim:
A semiconductor device, comprising: a first interlayer insulating layer; a plurality of wiring lines which are formed of copper (Cu), said plurality of wiring lines formed on said first interlayer insulating layer, at least two of said wiring lines being separated from each other by at least a distance predetermined to approach a value, approximately 0.2 to 0.3 μm, for which atoms of said Cu will be unlikely to diffuse through an insulator between said wiring lines in a quantity sufficient to allow a breakdown in an electrical insulation between said wiring lines; a first insulating layer which has a property that Cu atoms diffuse into said insulating layer in accordance with a diffusion gradient but is unlikely to enter said insulating layer beyond said predetermined distance, which said predetermined distance thereby effectively insulates between said plurality of wiring lines; and a second interlayer insulating layer formed on said first insulating layer having the property that the Cu is unlikely to enter therein, wherein said diffusion gradient of said first insulating layer has a surface region whose Cu concentration is equal to or higher than 10 19 atoms/cm 3 and approaches no more than an order of magnitude of 10 18 atoms/cm 3 within one-half of said predetermined distance.