Positive resists for electron-beam and X-ray lithography

For the first time the method of chemical modification of polymethylmethacrylate (PMMA) as a positive radiation resist which allows 2-3 fold increase of PMMA sensitivity to radiation without the lost of its high resolution has been proposed. Organohydridedisilanes (DS) have been used as modificators of the polymer. These modificators include Si-Si bonds weaker than C-C bonds which make a contribution to the increase of efficiency of the polymer chain scissions upon irradiation. Lines of 0.14 /spl mu/m width were produced in the 0.41 /spl mu/m thick PMMA films by electron-beam lithography. Based on the PMMA copolymers modified by DS two resists of 5-8 times higher sensitivity than PMMA and similar contrast have been developed.