Patent ID: 6433402
Filing Date: 2002-08-13
Classification: H01L

Abstract:
A semiconductor device comprising:an interlayer dielectric (ILD); a plurality of trenches in the ILD, the plurality of trenches comprising: a plurality of small trenches having a width no greater than a first width; and a plurality of large trenches having width greater than the first width; and metal lines filling the trenches; wherein: the metal lines filling the small trenches comprise substantially pure copper (Cu) or a first Cu alloy; and the metal lines filling the large trenches comprise a lower layer of substantially pure Cu or the first Cu alloy and an upper layer of a second Cu alloy on the lower layer, the second Cu alloy containing an element in a sufficient amount such that the electromigration resistance of the second Cu alloy is greater than that of substantially pure Cu and greater than that of the first Cu alloy.