A computational probe into the dissolution inhibitation effect of diazonaphthoquinone photoactive compounds on positive tone photosensitive polyimides

Abstract

Positive tone photosensitive polyimides ( p -PSPIs) composed of poly(amic acid) (PAA) and a diazonaph- thoquinone photoactive compound (DNQ PAC) have been greatly contributed to the progress of microelectronics. However, the relationships among PAC molecular structures, hydrogen-bonding interactions, and dissolution inhibitation for p -PSPIs have not been well understood. In this study, multiscale molecular modeling was utilized to evaluate such relationships. Density functional theory (DFT) calculations were used to predict the polarity of various DNQ PAC models and their corresponding indenylidene ketene (IK) compounds. Molecular dynamics (MD) simulations were performed to mimic the interactions between DNQ PAC and PAA polymer chains by calculating parameters such as the energy of mixing ( Δ E mix ) and Flory − Huggins parameter ( χ AB ). The computational results showed that χ AB values of PACs containing mono functional phenols signi fi cantly di ff ered before and after UV exposure. Their corresponding suppositional p -PSPI fi lms were found to form a “ skin layer ” by covering a high concentration of PAC on the surface of the fi lm. Experimental dissolution behavior measurements of selected p - PSPI fi lms strongly supported the computational observations. Succinctly, this work demonstrated the applicability of atomistic molecular simulations for the evaluation of dissolution inhibitation e ff ect of DNQ PACs and to understand the possible dissolution inhibition mechanisms of p -PSPIs