Pattern characterization of deep-ultraviolet photoresists by near-field infrared microscopy

A fiber-based near-field infrared (IR) microscope was used to achieve chemical contrast at subwavelength spatial resolution. The chief technical points enabling near-field infrared absorption measurements with respect to absorption sensitivity were discussed. The major contrast mechanisms involved in image formation were also studied. The correlations between the topography induced by acid catalyzed chemistry and characteristic IR absorption of the deprotected polymer were depicted by the IR images of polymer resists.