The semiconductor integrated circuit (IC) industry has experienced rapid growth. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. However, such scaling down has also been accompanied by increased complexity in design and manufacturing of devices incorporating these ICs, and, for these advances to be realized, similar developments in device fabrication are needed.
In one exemplary aspect, photolithography (or simply “lithography”) is a process used in micro-fabrication, such as semiconductor fabrication, to selectively remove parts of a thin film or a substrate. The process uses light to transfer a pattern (e.g., a geometric pattern) from a photomask to a light-sensitive layer (e.g., a photoresist layer) on the substrate. Recently, an extreme ultraviolet (EUV) radiation source has been utilized to provide reduced feature sizes due to its short exposure wavelengths (e.g., less than 100 nm). However, at such small dimensions, roughness of the edges of patterned features has become difficult to control during lithography processes. Accordingly, efforts have been made in modifying structures and compositions of photoresist materials to control such roughness and ensure proper patterning results. Though such modifications have been generally beneficial, they have not been entirely satisfactory. For these reasons and others, additional improvements are desirable.