Hydrogen silsesquioxane as a high resolution negative-tone resist for extreme ultraviolet lithography

Hydrogen silsesquioxane (HSQ) was evaluated as a high resolution negative-tone photoresist for extreme ultraviolet (EUV) lithography. The following imaging properties of HSQ were evaluated in EUV exposure: sensitivity, contrast, resolution, and line edge roughness (LER). In this article we report that HSQ has a sensitivity of $11.5mJ∕cm2$ with a contrast of 1.64 in EUV exposure and is able to resolve $26nm$ dense lines (⁠$70nm$ thick film) with a LER of $5.1nm$ $(3σ)$⁠. These results, especially with regard to the sensitivity and low line edge roughness, imply that this class of materials may hold distinct advantages over traditional chemically amplified resists and should be further explored for application in EUV lithography.