Patent ID: 6793796
Filing Date: 2004-09-21
Classification: C25D,H01L,H05K

Abstract:
A method of electroplating a metal onto a surface comprising a field region and a plurality of recessed features, the recessed features having a range of aspect ratios, the surface having a metal seed layer, the method comprising:contacting the surface with an electroplating solution comprising metal ions, a suppressor additive, an accelerator additive, and a leveler additive under conditions wherein the metal seed layer is cathodically polarized with respect to the electroplating solution prior to or less than approximately 5 seconds following the contacting; applying a DC cathodic current density through the surface, the current density having a first value that is sufficiently small that depletion of metal ions and the additives is absent at both the field region and the recessed features, to create a substantially conformal thin conductive metal film on the surface; applying a DC cathodic current density having a second value through the surface, the second value such that electroplating occurs preferentially on bottoms of recessed features having the largest aspect ratios; increasing the current density from the second value until all recessed features have aspect ratios less than about 0.5; and further increasing the current density to a third value that provides a condition of conformal plating, filling said recessed features and plating metal onto the field region.