DETERMINATION OF THE REFRACTIVE INDEX DEPENDENCE OF EXPOSED POSITIVE PHOTORESISTS ON THE PRELIMINARY HEAT TREATMENT CONDITIONS
P. E. Konoshenko1,2, S. L. Mikerin1, V. P. Korolkov1
1Institute of Automation and Electrometry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
2Novosibirsk State Technical University, Novosibirsk, Russia
Keywords: refractive index, photoresist, heat treatment, exposure
Abstract
The knowledge of the photoresist refractive index is useful for a number of applied tasks of controlling microelectronics technological processes, as well as for experimental studies of the characteristics of prototyped diffractive and micro-optical structures with deep microrelief. As this optical parameter depends on the photoresist treatment conditions, the spectral dependences provided at times by manufacturers may be insufficient. Research results of determining the refractive index dependence of positive photoresists S1818 G2 (MICROPOSIT) and FP-3535 (FRAST-M) in the wavelength range of 500-1600 nm on preliminary heat treatment conditions in the range of 15-30 min and exposure to actinic radiation are presented. The treatment of the investigated photoresists to obtain the refractive index within 1.61-1.64 in the visible spectral range and 1.59-1.61 in the near infrared spectral range of the emission spectrum is provided. An anomalous dispersion zone in the 570-640 nm wavelength range has been detected in films of the S1818 G2 dyed photoresist, which is often used in experimental characterization research in diffractive optical element prototyping. The dispersion curves for the Russian photoresist FP-3535 have been obtained for the first time.
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