Electroplating process for avoiding defects in metal features of integrated circuit devices
First Claim
1. 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.
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Accused Products
Abstract
Electroplating methods using an electroplating bath containing metal ions and a suppressor additive, an accelerator additive, and a leveler additive, together with controlling the current density applied to a substrate, avoid defects in plated films on substrates having features with a range of aspect ratios, while providing good filling and thickness distribution. The methods include, in succession, applying DC cathodic current densities optimized to form a conformal thin film on a seed layer, to provide bottom-up filling, preferentially on features having the largest aspect ratios, and to provide conformal plating of all features and adjacent field regions. Including a leveling agent in the electroplating bath produces films with better quality after subsequent processing.
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Citations
22 Claims
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1. 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:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of electroplating a metal onto a continuous conducting surface comprising a field region and a plurality of recessed features having a range of aspect ratios, the method comprising:
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contacting the surface with an electroplating solution comprising metal ions, a suppressor additive, an accelerator additive, and a leveler additive;
applying a DC cathodic current density through the surface, the current density having a first value such that electroplating occurs preferentially on bottoms of recessed features having the largest aspect ratios;
increasing the current density from the first value until all recessed features have aspect ratios of less than about 0.5; and
further increasing the current density to a second value that provides a condition of conformal plating, filling said recessed features and plating metal onto the field region. - View Dependent Claims (20, 21, 22)
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Specification