Positive-Working Alkaline-Developable Photosensitive Polyimide Precursor Based on Poly(amic acid) and Dissolution Inhibitor.

A poly(amic acid) (PAA) was prepared by ring-opening polyaddition of 4, 4′-hexafluoroisopropyridenebis(phthalic anhydride) and 1, 3-bis(4-aminophenoxy)benzene. The PAA film was very soluble to a tetramethylammonium hydroxide (TMAH) aqueous solution, whereas the dissolution inhibitor, 2, 3, 4-tris(1-oxo-2-diazonaphthoquinone-5-sulfonyloxy)-benzophenone (D5SB) effectively suppresses the solubility. This film could lead to polyimide exhibiting good thermal stability. An UV-vis.spectrum of the PAA film indicated excellent tranceparency to i-line (365nm) and the PAA containing 20wt% of D5SB showed a sensitivity of 100mJ/cm2 and contrast of 7.1, after exposed to i-line followed by developing with a 0.1% TMAH aq. at room temperture. When this pattern printed film was heated at 200°C for 24hour to derive polyimide film, the pattern was maintained without any flow through the imidization.