Acid generation and deprotecting reaction by diphenyliodonium 9,10-dimethoxyanthracene-2-sulfonate in a novolak positive photoresist based on chemical amplification |
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Authors: | Kazuhiko Naitoh Tsuguo Yamaoka Akira Umehara |
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Abstract: | In a positive photoresist composed of diphenyliodonium 9,10-dimethoxyanthracene-2-sulfonate as a novel photoacid generator, bisphenol A protected with tertbutoxycarbonyl group as a dissolution inhibitor, and a novolak resist matrix, the efficiency of photo-acid generation and deprotective reaction were investigated by means of UV-visible and IR spectroscopies. The quantitative measurement of photogenerated acid by using the acid-sensitive dye exhibited 0.18 as the quantum yield of acid generation in novolak resin film. The lithographic evaluation of this system as a chemically amplified resist was studied. The catalytic chain length for the acid-catalyzed deprotection step was determined as about 100 when 10 min post-exposure bake (PEB) at 80°C was given. The sensitivity and the resolution as a positive resist are 180 mJ/cm2 and higher than 1 μm, respectively under the PEB conditions mentioned above. |
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Keywords: | Photoacid generator Chemical amplification Positive photoresist |
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