New positive‐type photosensitive polymer based on poly(2,6‐dihydroxy‐1,5‐naphthylene) and diazonaphthoquinone

A positive working photosensitive polymer based on poly(2,6‐dihydroxy‐1,5‐naphthylene) (PDHN) with 1‐(1,1‐bis{4‐[2‐diazo‐1(2H)naphthalene‐5‐sulfonyloxy]phenyl}ethyl)‐4‐(1‐{4‐[2‐diazo‐1(2H)naphthalene‐5‐sulfonyloxy]phenyl}methylethyl) benzene (S‐DNQ) as a photosensitive compound has been developed. PDHN (number‐average molecular weight: 13,000; polydispersity index: 1.9) was prepared by oxidative coupling polymerization of the 2,6‐dihydroxynaphthalene‐benzylamine complex using iron(III) chloride hexahydrate in the solid state. A 10 wt % loss temperature of PDHN was 450 °C in air, and the film of 1 μm thickness showed excellent transparency above 400 nm. The resist system consisting of PDHN and S‐DNQ gave a clear positive pattern when it was exposed to 436 nm of light, followed by development with a 0.50 wt % aqueous tetramethylammonium hydroxide solution at 25 °C. The sensitivity (D) and contrast (γ) were 300 mJ/cm² and 2.1, respectively. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 393–398, 2002