Effective and environmentally friendly remover for photo resist and ashing residue for use in Cu/low-k process

The authors have developed an effective removal solvent for photo resist and its ashing residue for use in copper wire/low-dielectric interlayer devices that significantly lowers the risk of harming the environment. The inhibition of Cu corrosion is very important in these devices, and benzotriazole (BTA, C₆H₅N₃) is usually used as the corrosion inhibitor. However, BTA creates mutagenicity and biodegrades poorly. The authors investigate several typical heterocyclic nitrogen compounds as Cu inhibitors to replace BTA and study their optimum compositions. It has been found that uric acid (C₅H₄N₄O₃) is the best corrosion inhibitor for Cu. Moreover, this remover, which was composed mainly of amino alcohol, uric acid, and H₂O, can be applied to low-k films by optimizing its H₂O ratio. It not only effectively removed the ashing residue on Cu/low-k devices but also effectively reduced the environmental impact because the rinse wastewater containing remover can be completely treated at the fabrication site with ordinary biological processes.