Structural effects of DNQ-PAC backbone on resist lithographic properties

Model backbones without hydroxyl groups and fully esterified diazonaphthoquinone PACs were studied to identify critical structural parameters for dissolution inhibition in conventional diazonaphthoquinone/novolac photoresist systems. Hydrophobicity, presence of a site interactive with novolac, and proximaity of DNQ groups were identified as critical parameters. In general, the inhibiting ability of model compounds or PACs were found to be correlated with their retention time on reverse phase HPLC, a measure of hydrophobicity. Evidence is shown there to support the suggestion that the DNQ group provides a strong hydrogen bonding site to enhance efficiency of inhibition. PACs having DNQ groups in close proximity had lower inhibition than PACs with DNQs far apart.