Sub-45 nm SiO2 Etching with Stacked-Mask Process Using High-Bias-Frequency Dual-Frequency-Superimposed RF Capacitively Coupled Plasma

By using a stacked mask process (S-MAP) with spun-on-carbon (SOC) films 38 nm line patterns were successfully etched by controlling the ion energy using high-bias-frequency dual-frequency-superimposed (DFS) rf capacitively coupled plasma ill combination with the low hydrogen content SOC film. It was found that ions with higher energy enhance the fluorination of SOC and induce pattern wiggling under fluorine exposure. By Using a higher bias frequency to control the ion energy distribution and reduce the maximum ion energy, the SOC pattern wiggling, was effectively suppressed. [DOI: 10.1143/JJAP.47.8026]