Patent ID: 8906810

Claim:
A method of etching self-aligned vias and trenches in a multi-layer film stack supported by a temperature controlled electrostatic chuck in a plasma processing apparatus wherein the temperature controlled electrostatic chuck adjusts the temperature of the multi-layer film stack during etching of the self-aligned vias and trenches, the method comprising alternating steps of (a) etching low-k material beneath a metal hard mask (MHM) of titanium nitride containing material while maintaining the chuck at about 45 to 80° C. and (b) MHM rounding and Ti-based residues removal while maintaining the chuck at about 90 to 130° C. and repeating (a) and (b) at least once; wherein the low-k material and the metal hard mask in the repeating step (a) are the same as the low-k material and the metal hard mask in the original step (a).