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.

The anisotropic etching of organic films such as anti reflective coating (ARC) and resist for dry development using inductively coupled plasma (ICP) was studied. In ARC etching, the controllability of critical dimension (CD) and the selectivity to underlayers were investigated for O2 based gas chemistries by adding N2, He, CHF3, Cl2, HBr and SO2. The SO2/O2 chemistry has the advantage of both the CD controllability and the selectivity to underlayers. Field emission Auger electron spectroscopy (FE-AES) analysis revealed that the SO2 gas is useful for sidewall protection due to the sulfur deposition. In dry development etching, the controllability of the etched profile was investigated. It was dicovered that the Vpp (peak to peak voltage of RF bias) increases with increasing SO2 flow ratio to O2 so that a recession occurs in the silylated layer due to high ion energy. A vertical profile was obtained for a 0.13 µm pattern of resist and poly-Si optimizing SO2/O2 gas chemistry.