Feasibility study of CARL DUV-positive resist for 30-kV electron beam application and status of further resist development

Within top layer imaging techniques (TLI) the CARL [Microelectron. Eng. 20 (1993) 305; Microlithography World (1999) 2 and 16] technology (chemical am plification of resist lines) is widely used in i-line and DUV lithography. Because of the post development liquid silylation, which smoothes the struc ture edges by implantation of long chain silicon molecules, CARL has the ad vantage of a very low line edge roughness [J. Vac. Sci. Technol. B 17 (1999 ) 3122]. Further advantages are the additional gain in process window in di rection of overexposure and the possibility to shrink contact holes to smal ler sizes. These advantages are also interesting for mask and ASIC producti on. We studied the possibility of using the DUV-positive CARL resist in a 3 0-kV e-beam application and found this resist to be not usable for high-res olution implementation. Therefore we investigated the influence of the indi vidual resist components on the lithographic performance. Polymers consisti ng of chemically identical monomers were synthesized in different molecular ratios and processed as resists without other additives. Surprisingly only the solubility of the polymers showed an influence on the e-beam sensitivi ty. Next step was to examine different types of photoactive compounds (PAG) , e.g., with ionic or non ionic character, as e-beam sensitive catalysts. F inal goal of this status report was the development of a 70-nm node e-beam resist with a sufficient sensitivity, usable for fast mask and direct writi ng. (C) 2001 Published by Elsevier Science BY.