Neon soft x-ray lithography source based on low energy fast miniature plasma focus device

Abstract

Fast Miniature Plasma Focus Device (FMPF-3) device used for our experiments is of sub-kilojoule (100 – 240 J) energy capacity. It is an order of magnitude lesser than the other well established plasma focus devices that are generally used for neon soft x-ray emission studies. The prospect of enhancement of soft X-ray (SXR) (900 – 1600 eV) emission from this FMPF-3 device of 235 J (at 14 kV) storage energy have been thoroughly investigated with the motive of developing it as a neon soft X-ray lithography source. A detailed investigation on the influence of different geometrical parameters of the anode, the pressure of the filling gas and high-Z gas admixture on the SXR emission was done to enhance the neon SXR yield from FMPF-3. Apart from studying the influence of variation of above mentioned parameters on the soft X-ray emission, their influence on plasma dynamics has also been investigated using laser Shadowgraphy to analyze and understand the fundamental reason behind their influence and the results are presented. Definite understanding on the influence of the associated components on plasma dynamics would provide some crucial information for plasma researchers in the interpretation of their obtained results. This study also includes some preliminary studies which were done to understand the dosage and heat treatment requirements of the SU8 photoresist essential for pattern generation using X-ray lithography. Using Synchrotron as the X-ray source, SU8 photoresist was characterized in terms of its process parameters for various photoresist thicknesses. Accurate monitoring of the cross linking of the molecular chains of the photoresist due to the variation of process parameters was done using Fourier Transform Infra-Red (FTIR) spectrometer and the results are discussed.