Positive AZ-1518 photoresist are examples of photosensitive materials widely used in lithographic processes in microelectronics and optic for component relief manufacturing. This photoresist is composed of the photoactive compound (PAC) and the matrix material, which is a thick resin called novolak. When exposed to ultraviolet radiation induced chemical reactions modify their chemical and physical properties. Homogeneous thin films of these photosensitive materials were prepared on glass substrates. This work aims to measure the refractive index of films, exposed and unexposed to ultraviolet radiation, using the Abelès method. From the refractive index changes measurements in photosensitive films would be possible to obtain the fractional rate of decay of photoactive compound (PAC) per unit of intensity. Measurements of this rate provide important indications of microscopic chemical kinetics of photosensitive materials. The results show that the accuracy of the method is sufficient to measure the refractive index changes of these photosensitive materials type.
positive photoresist; Abelès method; thin films; ultraviolet radiation
