Development of top coat materials for ArF immersion lithography

We have investigated higher hydrophobic developer-soluble topcoat by combination of developer-soluble unit with higher hydrophobic unit. We have already reported a series of fluoropolymers, FUGU having a partially fluorinated monocyclic structure and having acidic hydroxyl group which act as dissolution unit into alkaline solution. In addition, recently we have developed new series of highly fluorinated monomers which was expected to act as hydrophobic unit. In this paper, we describe results of co-polymersization of FUGU with these hydrophobic monomers and evaluation of them. Some of them showed good hydrophobicity keeping moderate developer solubility. Furthermore, we found that higher hydrophobic developer-soluble materials were achieved by adding small amount of highly hydrophobic polymer to developer-soluble polymer, for example FUGU, and in fact this type of blending polymer showed high hydrophobicity keeping high dissolution. We have obtained various kind of new type of topcoat materials whose receding angle varied from 70-90 degree and patterning profile without dissolution residue could be obtained by using two beam interference.