A composition for forming an underlayer film for lithography for imparting excellent optical characteristics and etching resistance to an underlayer film for lithography, an underlayer film being formed of the composition and having a high refractive index (n) and a low extinction coefficient (k), being transparent, having high etching resistance, containing a significantly small amount of a sublimable component, and a method for forming a pattern using the underlayer film are provided. The composition for forming an underlayer film contains a naphthalene formaldehyde polymer having a specific unit obtained by reacting naphthalene and/or alkylnaphthalene with formaldehyde, and an organic solvent.
本发明提供了一种用于形成光刻用底层膜的组合物,该组合物可赋予光刻用底层膜优异的光学特性和抗蚀刻性,由该组合物形成的底层膜具有高折射率(n)和低消光系数(k)、透明、高抗蚀刻性、含有显著少量的可升华成分,以及使用该底层膜形成图案的方法。用于形成底层膜的组合物包含一种
萘甲醛聚合物(其特定单元通过
萘和/或烷基
萘与
甲醛反应而获得)和一种有机溶剂。