A combination of specular and off-specular neutron reflectometry was used to measure the buried lateral roughness of the reaction-diffusion front in a model extreme ultraviolet lithography photoresist. Compositional heterogeneity at the latent reaction-diffusion front has been proposed as a major cause of line edge roughness in photolithographic features. This work marks the first experimental observation of the longitudial and lateral compositional heterogeneity of a latent image, revealing the buried lateral length scale as well as the amplitude of inhomogeneity at the reaction-diffusion front. These measurements aid in determining the origins of line edge roughness formation, while exploring the materials limits of the current chemically amplified photoresists.
Citation: Applied Physics Letters
Pub Type: Journals
diffusion, line edge roughness, neutron reflectivity, off-specular reflectivity, photolithography