Cinética química em fotorresinas usando espectrometria de massa LDI-ToF de alta resolução

Abstract

Positive photoresists are photosensitive materials widely used in lithographic processes in microelectronics and optic for component relief manufacturing. The photoresists are used as masks for transferring of geometric patterns to produce more than 95% of the integrated circuits employed in microelectronics. In optics, the photoresists are used in the fabrication of periodic structures with diffractive optical properties. An important technique of the characterization of such photoresists is the mass spectrometry. This spectrosmetry tool is very powerful in the study of surfaces, control processes of film growth in microelectronics and other branching of science. In this context, this work presents results of the degradation processes of the AZ-1518 photoresist due to exposure to ultraviolet radiation. The degradation products occasioned by the action of ultraviolet radiation is analyzed by time-of-flight mass spectrometry using laser desorption ionization (LDI). The chemical kinetics of photoresist, according to the method proposed by Dill, shows that the rate of temporal variation of the concentration of photoactive compound is proportional to the intensity of incident light. This parameter is measured using the exposure to a typical mercury arc lamp spectrum (365, 405 and 436 nm wavelengths). In view of the results presented, takes us up to believe that the technique of laser desorption ionization is able to identify the molecular modifications in the photoresist due to exposure to ultraviolet light showing differences in the relative intensities of the mass spectra of the samples unexposed and exposed to ultraviolet radiation. Because of the variations in the relative intensities of the mass spectra of the samples that received different exposure energies, it was possible to characterize the chemical kinetics of the AZ-1518 photoresist. This result shows that the technique of laser desorption ionization is appropriate for the study of chemical kinetics of photosensitive materials and to obtain the Dill parameter of positive photoresists.