Evaluation of a novel unfluorinated copper precursor for chemical vapor deposition
A kinetics of the chemical vapor deposition (CVD) of copper using novel unfluorinated precursor, copper(I)(N(1(dimethylvinylsiloxy)-1-methylethano)-2-imino-4-pentanoate), namely Cu-KI5, was studied. Since its great thermal stability, Cu-KI5 allowed high source temperature to provide high vapor pressure, for example Cu-KI5 has a vapor pressure of 0.22.2Torr at the temperature range of 100140C. Furthermore, copper could be deposited by direct reduction from Cu-KI5 instead of disproportionation. By using formic acid (HCOOH) as a reducing agent, copper films were deposited on ruthenium substrate at temperature range of 150350C. The activation energy was 48.9kJ/mol in surface reaction limited region ( 210C) at the total pressure of 5Torr. Secondary ion mass spectroscopy (SIMS) analysis showed that CVD copper film of high purity (>99.99%) was deposited at 250C. The as-deposited copper films grown at 150300C exhibited strong ?111? preferred orientation. The minimum resistivity of the copper film was 1.77??cm obtained at the deposition temperature of 250C. In the surface reaction limited region, kinetic data extracted from experiments enabled 2-D computational simulation to predict copper deposition into trench structures. Simulation results showed excellent step coverage, which was larger than 90% for aspect ratio of 10:1. Cu-KI5 is a promising Cu-CVD precursor for the fabrication of ultra large scale integration (ULSI) or through silicon via (TSV) copper interconnects.
unfluorinated precursor metallization copper cvd kinetic analysis