Infrared Band-Specific Near Field Optical Microscopy Probing of Chemically Amplified Polymer Photoresists

University Of Colorado At Boulder, Boulder CO

Investigators

Abstract

This project will explore mechanisms, line dimensions, and acid diffusion rates in acid catalyzed, chemically amplified deep ultraviolet (UV) photoresists using infrared near field scanning optical microscopy(IR NSOM). The objectives are to (1)develop a higher resolution variant of tunable laser infrared near field scanning optical microscopy, (2)push the limits of spatial resolution to 10 nm, (3)use the method to study state-of-the-art samples of photolithographically generated lines in deep-UV chemically amplified polymer photoresists, and (4) to probe the diffusion properties of the acid species. IR NSOM is a chemically band-specific optical characterization technique that offers an adaptable method to study features and line dimensions. It can be applied in many situations and as new chemical components are introduced into polymer chemistries for deep-UV lithographic applications for smaller line dimensions. The basis for the contrast mechanism is that the absorption features in the polymer films before and after UV exposure and post exposure bake show dramatic wavelength-specific changes in infrared vibrational bands. When the contrast is properly accounted for with regard to both absorption and index of refraction changes, the method provides a highly sensitive way of detecting chemical transformations on a nanoscopic scale. Wavelength-specific IR NSOM is expected to provide an important new route to characterize line dimensions and to study acid diffusion rates quantitatively. %%% The project addresses basic research issues in a topical area of materials science with high technological relevance. New experimental tools are now becoming available to allow high resolution of elementary chemical and diffusion processes which when better understood allow advances in fundamental materials science and technology. The basic knowledge and understanding gained from the research is expected to contribute to improving the ability to lithographically define smaller and higher resolution components for advanced devices and circuits. An important feature of the program is the integration of research and education through the training of students in a fundamentally and technologically significant area. ***