Innovative optical crosslinking process on PFAS-free underlayers for enhanced sustainability in EUV lithography

As the semiconductor industry advances toward smaller pitches, the increasing complexity of process steps and nodes raises significant concerns regarding environmental degradation and climate change. In energy-intensive semiconductor manufacturing, electricity consumption presents a complex challenge, and energy solutions aimed at developing sustainable semiconductor technologies have emerged as a critical focus. In a previous study, we demonstrated an energy-efficient optical crosslinking system using light-curable underlayers for Extreme Ultraviolet Lithography (EUVL) without heat treatment, offering a solution to this challenge. This approach replaces conventional thermal baking, which consumes significant electricity energy due to the high temperature required to completely crosslink the Spin-on Carbon (SOC) and Spin-on Glass (SOG). In this work, we introduced not only an innovative optical crosslinking process but also novel per-and perfluoroalkyl substances (PFAS)-free underlayers provided by Brewer Science, which mitigate permanent environmental impacts and reduce the potential for bioaccumulation. We confirmed complete film crosslinking for the PFAS-free underlayers at a low dose, achieving approximately an 85% reduction of SOC and a 60% reduction of SOG in energy savings without compromising patterning performance. By leveraging innovative SCREEN track technologies and PFAS-free underlayers, this technological differentiation allows the semiconductor industry to prioritize energy sustainability as a key value and offers significant improvements in energy consumption. This contributes to balancing environmental sustainability with advancements in semiconductor technology.