Suppression of 193-nm photoresist deformation by H2 addition to fluorocarbon plasma in via-hole etching

Suppression of 193-nm photoresist deformation by H2 addition to fluorocarbon plasmas in via-hole etching is investigated for sub-65-nm-node dual-damascene patterning. Photoresist deformation causes profile distortion and results in degradation of reliability, such as the line-to-line time dependent dielectric breakdown. To prevent profile distortion, H2 addition to fluorocarbon plasma is investigated in terms of fluorocarbon polymer and photoresist modification. XPS, FT-IR, and highlight etching investigations reveal that the H2 plasma treatment extracts oxygen from the photoresist and modifies it. This modification suppresses the photoresist deformation and H2 addition to fluorocarbon plasmas can have the same effects as the H2 plasma treatment. Finally, a highly reliable damascene interconnection is successfully achieved.