Novel resists for nanolithography

This thesis describes the experimental study of two new families of low molecular mass electron beam resists for nanolithography. The field of nanolithography is introduced and the motivations for the development of new electron beam resists are examined. The experimental techniques used in this work are then described, and a summary of the results presented in the research papers included in the thesis is presented. The detailed results are presented via these papers in the final chapter, and referred to, in the first three chapters, as Papers I to VI. A systematic study of the response of eleven methanofullerenes and thirteen polysubstituted triphenylene derivatives to electron beam irradiation is presented. Films of the compounds have been prepared on the hydrogen terminated silicon (100) surface by spin coating from solution in solvents such as chloroform. The film thicknesses could be controlled by varying the solution concentration or the rotational frequency of the sample during deposition. The films were irradiated using a 20 keV electron beam. All of the compounds demonstrated negative tone resist behaviour after development with non-polar solvents such as monochlorobenzene. The methanofullerene resists demonstrated sensitivities of #approx# 8.2 x 10"-"3 to #approx# 8.5 x 10"-"4 C/cm"2 with the increase in sensitivity being approximately proportional to the increase in molecular mass. In comparison the sensitivity of C_6_0 is #approx# 1 x 10"-"2 C/cm"2. The polysubstituted triphenylene derivatives demonstrated negative tone sensitivities in the range #approx# 1.5 x 10"-"3 to #approx# 6.5 x 10"-"3 C/cm"2, again increasing in an approximately linear manner with molecular mass. The derivative hexapentyloxytriphenylene behaved as a positive tone resist for electron doses between #approx# 3 x 10"-"4 and #approx# 2.5 x 10"-"3 C/cm"2 with developers such as 2-pentanol. The negative tone resolution of the compounds was found to be at least as good as 20 nm in most cases and #approx# 14 nm in the case of hexa-pentyloxytriphenylene. The etch durabilities of these compounds, for dry plasma etching with SF_6, are very high -- at least double that of a conventional high durability novolac resist for the methanofullerenes and approximately double the novolac durability for the polysubstituted triphenylene derivatives. (author)Available from British Library Document Supply Centre-DSC:DXN047675 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo