Deposition of Copper Films with Surface-Activating Agents

Abstract

The low-temperature deposition of clean, conformal copper film by a vapor phase process using Cu(I) β-diketimine complex 1 is described. The process is similar to the digital CVD process described earlier with the related Cu(I) complex 2 in requiring pulse-and-purge cycles of reagents. However, here a surface-activating agent is used to capture the Cu precursor on the substrate surface through an acid–base reaction, rather than relying on a thermal decomposition of the Cu precursor from the vapor phase. The substrate temperature for the acid–base reaction is significantly lower than that for the thermal reaction, avoiding thermal degradation of the precursor during the deposition reaction, and is just high enough to volatilize the copper complex. The deposition process involves pule-and-purge cycles of pyrazole, copper precursor, and reducing agent. Thin, clean, conformal copper films on Au–Si and Ru–Si substrates are generated.