Micropattern Formation of Photosensitive Imide Block Copolymer Thick Films

In order to determine the optimal composition for thick films above 10 μm of a photosensitive imide block copolymer/sensitizer composite, we examined the dissolution rates of the exposed and unexposed area, their dissolution contrast and pattern profile during the development of films prepared using a nonprecursor-type imide block copolymer (PI 21-101) with the addition of various sensitizer concentrations of diazonaphthoquinone derivative (THBP-200) from 15 wt% to 50 wt%. The dependence of the dissolution rate on THBP-200 concentration for the ?lms not subjected to the exposing process signifies that the dissolution inhibition above 30 wt% is effective to an alkaline development solution. The dissolution contrast with 30-wt% THBP-200 was found to be 15.4, which is remarkably higher than that with THBP-200 concentrations of 15 wt% and 20 wt% that are the optimal composition for thin films. With the condition of a THBP-200 concentration of 30 wt%, the optimum composition for the present thick films, a good via-hole pattern with a hole size of 20 μm was successfully formed on a film with about 10 μm in thickness.