Effects of Bias, Pressure and Temperature in Plasma Damage of Ultra Low-k Films

摘要

1. Degree of plasma damage (hydrophilisation) depends on chemistry, pressure, ion energy and temperature. 2. Comparison of samples 2-5 with 19-20 (Figure 2) demonstrates that Ar ion bombardment densifies the film but they remain sufficiently hydrophobic. NH_3 plasma even without intensive ion bombardment makes low-k film extremely hydrophilic. 4. Temperature decreases degree of hydrophobisation but increases densification. 3. Degree of damage in N_2/H_2 plasma depends on exposure time. Maximum damage in SF_6/O_2 plasma is succeeded very fast and no time dependence was observed. Degree of damage in CF_4/O_2 plasma is much smaller than in SF_6/O_2 plasma, probably because of limitation of penetration of O radicals by adsorbed CFx radicals and CFx polymer. 4. Helium pre-treatment and He additive to H_2 plasma decrease the plasma damage, especially at moderate temperatures.