Transmission near-field scanning microscope for infrared chemical imaging

We report transmission infrared near-field scanning microscopy (IR-NSOM) imaging of chemically amplified photoresist polymers patterned by ultraviolet exposure. Chemical specificity was attained using infrared wavelengths tuned to the 3 μm OH stretch absorption band of the polymer, a band sensitive to the chemical changes characteristic of the lithographic photochemical process of this material. Contrast mechanisms are discussed together with the IR-NSOM specifics, such as the fabrication of an infrared near-field probe with high throughput, which lead to an attainable resolution of λ/10 and a transmission sensitivity of 1%. © 1999 American Institute of Physics.