Patent ID: 8691701

Claim:
A method for forming etched features in a low-k dielectric layer disposed below a photoresist mask in a plasma processing chamber, comprising: etching features into the low-k dielectric layer through the photoresist mask; and stripping the photoresist mask after the features are etched into the low-k dielectric layer, wherein the stripping the photoresist mask comprises a plurality of cycles, wherein each cycle comprises: a fluorocarbon stripping phase, comprising: flowing a fluorocarbon stripping gas into the plasma processing chamber, wherein the fluorocarbon stripping gas comprises fluorocarbon; forming sidewalls during the fluorocarbon stripping phase; forming a plasma from the fluorocarbon stripping gas; forming sidewalls using the plasma; stripping at least some of the photoresist mask using the plasma; and stopping the flow of the fluorocarbon stripping gas into the plasma processing chamber; and a reduced fluorocarbon stripping phase, comprising: flowing a reduced fluorocarbon stripping gas that has a lower fluorocarbon flow rate than the fluorocarbon stripping gas into the plasma processing chamber, wherein the fluorocarbon of the fluorocarbon stripping gas is at least one of C 4 F 6 and C 4 F 8 ; forming the plasma from the reduced fluorocarbon stripping gas; removing at least some of the sidewalls using the plasma; stripping at least some of the photoresist mask using the plasma; and stopping the flow of the reduced fluorocarbon stripping gas.