A new photoresist based on poly(propyleneimine) dendrimer

Poly(propyleneimine)-based alkaline soluble dendrimer 2 was prepared by the Michael addition reaction of poly(propyleneimine) dendrimer (PPID) with N-(2-hydroxy-5-methylphenyl)-2-propenamide. The obtained 2 was well-dissolved in common organic solvents and its film was transparent above 300 nm. The dissolution behavior of the 2 film containing 30 wt% of 1-{1,1-bis[4-(2-diazo-1 (2H)naphthalenone-5-sulfonyloxy)-phenyl]ethyl}-4-{1-[4-(2-diazo-1 (2H)naphthalenone-5-sulfonyloxy)phenyl]-methylethyl}-benzene (DNQ) after exposure was studied and it was found that the conventional base developer, a 2.38 wt% aqueous tetramethylammonium hydroxide TMAH solution was too alkaline to obtain sufficient dissolution contrast. Therefore, a diluted TMAH developer [0.7 wt%] was used for the positive-type system. Then an unexposed area was completely insoluble, on the other hand an exposed area showed an adequate dissolution rate. The photoresist system containing 30 wt% of DNQ showed a sensitivity of 80 mJ/cm² and a contrast of 5.3 with 365 nm light. A series of process, that is, imagewise exposure, heat treatment, flood exposure, and development for the resist system resulted in negative-type image.