Suppression of 193-nm photoresist deformation by H-2 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, H-2 addition to fluorocarbon plasma is investigated in terms of fluorocarbon polymer and photoresist modification. XPS, FT-IR, and highlight etching investigations reveal that the H-2 plasma treatment extracts oxygen from the photoresist and modifies it. This modification suppresses the photoresist deformation and H-2 addition to fluorocarbon plasmas can have the same effects as the H-2 plasma treatment. Finally, a highly reliable damascene interconnection is successfully achieved. (c) 2006 Elsevier B.V. All rights reserved.