Low Temperature Process with Flourine Addition

An alternative for the pure high temperature $\rm O_2$ process is a $\rm O_2/CF_4$ chemistry. This process can be carried out also at room temperature because the F radicales remove H from the resist, leaving open bonds that can be attacked even by room temperature by oxygen. There is the additional advantage that also some inorganic residues can be removed by the flourine radicals for the price of slightly reduced selelectivity to Si as well as SiO2. Additional species can be added to the process above for dedicated purposes e. g. to enhance selectivity, improve residue removal (or make them at least water soluble) so used chemistries could consist of: $\rm O_2$, $\rm CF_4$, $\rm CHF_3$, $\rm CH_2F_2$, $\rm N_2/H_2$, $\rm NH_3$, $\rm H_20$.