Improvement of dry etching resistance of resists by deep UV cure

The improvement of dry etching resistance of photoresists by the deep UV cu re has been attempted. We have tried deep UV cure under N-2 gas flow for Kr F chemically amplified resists and obtained the same level of etching rates as novolak resists. While the rates increased under dry air. The resists a fter deep UV cure under both N-2 and dry air were found to be cross-linked. The increase of carbonyl in Fourier transform infrared (FT-IR) spectra und er dry air may suggest that oxygen atoms in the polymer structure reduce th e etching resistance. For ArF resists, the combination of the incorporation of acryl unit into methacrylate polymer and deep UV cure under N-2 was an effective method for improving the dry etching resistance. Using the model ArF resist consisting of acryl polymer, we obtained the same dry etching re sistance as a KrF resist with inhibiting film shrinkage by optimizing the p arameters of the deep UV cure.