Reaction mechanisms in silicon-based resist materials: polysilanes for deep-UV, EUV, and x-ray lithography

The present paper describes mechanisms of photo- and radiation induced reactions in silicon based resist materials: polysilanes with Si-branchings and Si-H bondings, as a candidate for EUV and X-ray resist materials. Polysilanes have been previously confirmed to show positive-type resist properties for UV light, electron beams (EB), X-rays, etc. at any conditions. However the cross-linking reaction of the polymer became dominant in the polysilane with Si-branchings upon irradiation to UV light, EB, and ion beams. The efficiency of the cross-linking reaction strongly depended on the ratio of Si-branching giving polymer gels in the polysilane with higher amount of Si-branching than 5% even for (gamma) -ray irradiation. Polyhydrosilanes containing vinyl groups revealed to cause efficient cross-linking reactions with the presence of catalysts for hydrosilylation upon exposure to deep UV or X-rays, leading to high-sensitive negative resist materials for EUV lithography.