In current semiconductor manufacturing processes, hardmasks have become more prevalent in patterning of small features. A silicon-containing hardmask, which can be spun onto wafers, is desirable in terms of mass production throughput and cost of ownership. Previously, we reported a paper on silicon-based anti-reflective spin-on hardmask materials for 193 nm lithography. In this paper, hardmask materials for 45 nm pattern of immersion ArF lithography are described. To achieve 45 nm patterning, a different base resin platform from the previous paper has been used. Furthermore, we have improved the etch resistance by changing our synthesis method without modifying the resin platform and silicon contents. Despite these changes, an excellent storage stability, which is one of the essential requirements for the materials, is still maintained. Characterization and lithographic performance of 45 nm immersion ArF lithography using our new materials are described in detail.