The effects of amine base quencher on the photoacid catalyzed deprotection reaction-diffusion front in model photoresists was measured by combination of neutron reflectivity and Fourier transform infrared spectroscopy. Modulation in the location of the base in reference to the diffusing photoacid catalyst illuminates the complex role base plays in defining the reaction-diffusion front shape through changes in the spatial reaction extent. Despite similar total extents of reaction, comparison of uniform base and model photodegradable base geometries demonstrate distinct reaction time and base concentration effects on the latent deprotection profile shape. These differences arise from the modification of the initial deprotection extent through neutralization of the photoacid and subsequent feedback in the reaction-diffusion process. Use of the model photodegradable base results in a sharper front due to these effects.Lastly, aqueous hydroxide development of these latent images demonstrates a limit to the improvement in feature quality obtained from sharpening of the deprotection profile with these base additives.
Citation: Journal of Vacuum Science and Technology B
Pub Type: Journals
chemically amplified photoresists, diffusion, neutron reflectivity, photolithography