Silicon Containing Organic-Inorganic Hybrid Materials as EUV Photoresists

The opportunities posed by extreme ultraviolet (EUV) lithography are encouraging the development of new resist platforms. The absorbance characteristic of materials required for the EUV lithography demands the use of polymers containing highly transparent silicon atoms. At the same time, very low levels of outgassing of silicon containing fragments are required due to the vacuum environment present during exposure and the extremely high cost of the EUV tools. These two contradictory requirements have led us to pursue new types of silicon containing hybrid materials as a resist platform; chemically amplifiable polysilanes and silsesquiazanes. In the former case, the direct incorporation of acid sensitive groups into the polymer backbone allows for a solubility switch upon exposure. In the later system, a silicon-nitrogen backbone structure can be cleaved upon exposure to induce a solubility switch. These hybrid materials possess many useful properties including low absorbance, low outgassing, and high sensitivity. Silsesquiazanes having different substituents and branching ratios were synthesized. The properties of the polymers will be discussed in the context of their lithographic performance.