Combinatorial Methods Study of Confinement Effects on the Reaction Front in Ultrathin Chemically Amplified Photoresists

Sub‐100 nm lithography requires more understanding of photoresist material properties and processing conditions to achieve necessary critical dimension control of patterned structures. As resist thickness and feature linewidth decrease, fundamental material properties of the confined resist polymer can deviate from bulk values and impact important processing parameters such as the postexposure bake (PEB) temperature. The significance of these confinement‐induced deviations on image or linewidth spread have just been reported recently by Goldfarb et al.. Using a high throughput combinatorial method, we explore this problem much more efficiently, and thoroughly, while offering an increased amount of data. In this work, we employed temperature and thickness gradients to characterize the spatial extent of the reaction‐diffusion process in a model chemically amplified photoresist system as a function of PEB temperature and protected polymer thickness. Bilayer samples were prepared with a bottom layer of a prot...