Diphenyliodonium Salts with Diazoxide Group for A Photo-acid Generator

We designed diphenyliodonium salts with diazoxide group for a photo-acid generator (PAG) in chemically amplified resists. The absorption coefficients at 365 nm for the new PAGs were 103 -104 orders, originating in diazoxide structure. The quantum yield for acid generation irradiating 365 nm wavelength light of diphenyliodonium 1-diazo-2-hydroxynaphthalene-4-sulfonate (AZO-DPI) and diphenyliodonium 1-diazo-2-hydroxy-6-nitronaphthalene-4-sulfonate (NO2-AZO-DPI) was 0.21 and 0.14, respectively. The thermal stability of AZO-DPI and NO2-AZO-DPI were 144.2 and 153.2°C, respectively. The photosensitivity of AZO-DPI and NO2-AZO-DPI irradiating 365 nm wavelength light in polymer bearing ethoxyethyl protecting group were 120 and 98 mJ/cm2, respectively. The diphenyliodonium salt is the promising PAG sensitizing for 365 nm chemically amplified resists.