<p>For filling an interconnect opening of an integrated circuit formed on a semiconductor substrate, an underlying material is formed at any exposed walls of the interconnect opening. A sacrificial layer of protective material is formed on the underlying material at the walls of the interconnect opening. The underlying material and the sacrificial layer of protective material are formed without a vacuum break. The protective material of the sacrificial layer is soluble in an acidic catalytic solution used for depositing a catalytic seed layer. The semiconductor substrate having the interconnect opening is placed within an acidic catalytic solution for depositing a catalytic seed layer. The sacrificial layer of protective material is dissolved away from the underlying material by the acidic catalytic solution such that the underlying material is exposed to the acidic catalytic solution. A catalytic seed layer formed from the acidic catalytic solution is deposited on the exposed underlying material at the walls of the interconnect opening. The conductive fill for filling the interconnect opening is grown from the catalytic seed layer by electroless deposition. The present invention may be used to particular advantage when the underlying material is comprised of tantalum as a diffusion barrier material, and when the protective material of the sacrificial layer is comprised of magnesium. In that case, the acidic catalytic solution includes palladium chloride and/or tin chloride with hydrochloric acid for dissolving the sacrificial layer of protective material.</p>
Dr. Krishnashree Achuthan and Lopatin, S., “Formation without vacuum break of sacrificial layer that dissolves in acidic activation solution within interconnect”, 2002.