An evaluation of nitrobenzylester chemistry for chemical amplification resist process.
01 January 1988
Three esters, 2-nitrobenzyl-, 2,4-dinitrobenzyl-, and 2,6-dinitrobenzyl tosylate, were synthesized and evaluated as photoprotected toluene sulfonic acids. These materials are of interest because they are nonionic, highly soluble agents for the deep UV photogeneration of acid, and may be particularly useful in certain microelectronic applications where the demand for a low dielectric constant material dictates the use of nonionic materials in processing. The effectiveness of these tosylate esters as photogenerators of acid was evaluated by determining their quantum efficiency, thermal and hydrolytic stability, and by comparing the lithographic sensitivities of resist systems consisting of the esters and poly(t-BOC)alpha-methystyrene. The 2,6-dinitrobenzyl tosylate system exhibited a sensitivity of ~100 mJ/cm sup 2 upon conventional UV or 248nm excimer laser exposure, and has a contrast of 3. 2.