Cu-Oxide-Assisted Selective Pyrolysis of Organic Nanolayer on Patterned SiO2-Cu Surface

Organic nanolayers attract much attention for the isolation and adhesion promotion of the Cu line and insulator in Cu interconnection of microelectronic devices. This paper proposes a strategy for selective formation of adhesion nanolayer on the insulator surface with etching it on Cu surface by Cu-oxide-assisted pyrolysis. After deposition of a uniform polyelectrolyte layer on both SiO2 and Cu surfaces, heat treatment at 350 degrees C in ambient nitrogen was applied. Then, a larger thickness decrease was observed on the polyelectrolyte layer on Cu when compared to that on SiO2. According to the TDS and XPS analysis, the polyelectrolyte layer was relatively stable on SiO2 up to the intrinsic decomposition temperature of the material, but on the Cu surface it decomposed to volatile small molecules at a lower temperature due to Cu2O-assisted oxidization. This substrate dependent selective pyrolysis was examined for 100 nm width Cu lines and SiO2 spaces, and then a patterned polyelectrolyte layer on the SiO2 surface was obtained with a single nanometer scale edge resolution.