Abstract: In integrated circuits having copper interconnect and low-k interlayer dielectrics, a problem of open circuits after heat treatment was discovered and solved by the use of a first liner layer of Ti, followed by a conformal liner layer of CVD TiN, followed in turn by a final liner layer of Ta or TaN, thus improving adhesion between the via and the underlying copper layer while reducing the increase in resistance caused by alloying between the Ti and the Copper to an acceptable amount.

Abstract: A conductive layer in a semiconductor device is protected against chemical attack by a photoresist developer by forming a protective film overlying the conductive layer. The protective film is formed using a chemical reaction that occurs through defects in a passivation layer that was previously formed overlying the conductive layer. The chemical reaction substantially occurs at the surface of the conductive layer and chemically converts portions thereof in forming the protective film. Preferably, the conductive layer is aluminum or an alloy thereof containing copper and/or silicon, and the protective film is aluminum oxide formed on the aluminum layer to protect it from corrosion by tetramethyl ammonium hydroxide (TMAH). The passivation layer is TiN, and the chemical reaction used is oxidation of the aluminum layer through defects in the overlying TiN layer by placing in an ozone asher.