Kinetics of Deposition of Cu Thin Films in Supercritical Carbon Dioxide Solutions from a F-Free Copper(II) β -Diketone Complex

Kinetics of deposition of Cu thin films in supercritical carbon dioxide solutions from copper bis(di-isobutyrylmethanate) {Cu[(CH 3 ) 2 CH(CO)CH(CO)CH(CH 3 ) 2 ] 2 }, Cu(dibm) 2 ), a F-free copper(II) complex, via hydrogen reduction were studied. A flow-type reaction system was employed to control each deposition parameter independently and at a constant value. Apparent activation energies for Cu growth were determined for a temperature range of 200―260°C as a function of hydrogen concentration. The determined values varied from 0.35 to 0.63 eV and decreased as hydrogen concentration increased. At a deposition temperature of 200°C, growth rate followed a Langmuir-type dependence against Cu(dibm) 2 and hydrogen concentrations, showing first-order dependence at lower concentrations and zero-order dependence at higher concentrations. At a higher deposition temperature of 240°C, no saturation in the growth rate was observed. A Langmuir―Hinshelwood-type growth mechanism was discussed, and a rate equation for growth was proposed, taking into account the temperature dependence of both the rate constant of the rate-determining reaction and adsorption equilibrium constants. The hydrogen concentration dependence of the apparent activation energy for Cu growth was discussed with this rate equation.