In-situ plasma ash/treatment after via etch of low-k films for poison-free dual damascene trench patterning

摘要

After via etch, a low-k dielectric layer (104) is treated with an in-situ O2 plasma. Resist poisoning is caused by a N source that causes an interaction between low-k films (104), such as OSG, and DUV resist (130, 132). The in-situ plasma treatment immediately removes the source of poisoning to reduce or eliminate poisoning at trench patterning.