Patent ID: 8430992

Claim:
An apparatus for forming a protective self aligned buffer layer within a metal layer in a partially fabricated semiconductor device, the apparatus comprising: (a) a process chamber having an inlet for introduction of reactants; (b) a support for holding the partially fabricated semiconductor device in position during formation of the protective self aligned buffer layer; and (c) a controller, associated with the process chamber, the controller comprising program instructions for: (i) pre-cleaning the partially fabricated semiconductor device to at least partially remove metal oxide from the metal layers by treating the surface of the partially fabricated semiconductor device with a plasma comprising a reducing gas; (ii) after the pre-cleaning, contacting the partially fabricated semiconductor device with a nitrogen containing reactant for a period of time in an absence of plasma, wherein the nitrogen containing reactant interacts with the exposed metal surface of a metal layer, to form a metal nitride at the surface of said metal layer, thereby passivating said metal surface; and (iii) subsequently contacting the partially fabricated semiconductor device with a second reactant in an absence of plasma, such that the second reactant reacts with unpassivated metal atoms of the metal layer and chemically transforms the top portion of the metal layer into a first protective self-aligned buffer layer, wherein said first protective self-aligned buffer layer resides entirely within said metal layer.