RESEARCH ACTIVITIES OF PHOTOLITHOGRAPHY BY SYNCHROTRON-RADIATION FROMINDUS-1 AND INDUS-2

Our electron storage ring Indus-1 (450 MeV, 100 mA) will soon be commi ssioned. The critical wavelength is 61 Angstrom. Using the wiggler, sp ectral flux can be enhanced at 10 Angstrom. Hence our research work is oriented to: (i) development of master masks both for contact and pro ximity printing, (ii) a study of the effects of VUV and soft X-rays fr om synchrotron source on photoresists in SXRL. Mylar is chosen in this region as a master mask substrate for its excellent optical propertie s. Using the conventional photoresist system in UV lithography, patter n details of 5 mu m were printed on Mylar deposited with Au-Cr films. Later on, by depositing Ti-Pd-Au films and Waycoat resists, pattern de lineation by optical lithography gave resolution features as small as 1.2 mu m. Resists of both positive and negative tones were used. UV ex posure (10 mW/cm(2) for 7 s) was done under ambient conditions. Contra st details of pattern were estimated by measuring the optical densitie s. To investigate the fundamental aspects of resist decomposition by S R radiation, (5 to 20 Angstrom) from Indus-2, mass spectrometric analy sis of residual gases is performed. It is most probable, that the PMMA and Novolac-based resists with light sensitive resins may be changed to a chemically different layer for example a highly cross linked laye r. Resist coated Si wafers were held inside a multiport UHV chamber fi tted with QMS and gauge heads, which was evacuated to 1 X 10(-6) Pa by TMP and sputter ion pump. Unfiltered UV radiation excited the resists whose energy is measured using a thermopile. Chemical reactions of th e resists, when exposed by DW, soft X-ray or electron beam are discuss ed. Resist annealing may be essential to withstand SR radiation. The a bove experimental data from the resists irradiated by synchrotron radi ation is of paramount importance especially when we do SXRL work in In dus-2. We also plan to introduce the LIGA process for making special o ptical and micromechanical devices using SXRL. Results and experiments of the above works are discussed.