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Sensitivity of diazoquinone resists to optical and electron‐beam exposure
Author(s) -
Kaplan Michael,
Meyerhofer Dietrich
Publication year - 1980
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760201607
Subject(s) - resist , materials science , absorption (acoustics) , irradiation , photochemistry , electron , chromophore , cathode ray , quantum yield , wavelength , solubility , radiation , absorption spectroscopy , analytical chemistry (journal) , optoelectronics , fluorescence , optics , chemistry , nanotechnology , organic chemistry , composite material , physics , layer (electronics) , quantum mechanics , nuclear physics
This paper compares the response of resists consisting of novolak resin and diazoquinone sensitizers (inhibitors) to optical and electron‐beam radiation. In both cases, irradiation destroys the sensitizer leading to an increased rate of solubility in alkaline developer. For optical exposure in the near‐uv region, the light is absorbed only by the chromophore sites and a unique quantum efficiency of 0.30 ± 0.03 can be measured for a range of wavelengths and sensitizers (10.5 ± 1.0 eV/bleached site). In the case of electron‐beam exposure, the initial rate of bleaching in pure sensitizer implies that 7.6 ± 0.6 sites are destroyed per 100 eV absorbed (13 ± 1 eV/molecule). In mixtures of sensitizer and resin (i.e., resists), this inherent sensitivity, or G ‐value, based on the calculated absorption by the sensitizer only, increases by almost a factor of 2 as the proportion of resin is increased. While the electron and optical exposure both destroy the sensitizer center, absorption spectra and solubility properties show that the end products of the chemical reactions are not the same in the two cases. In addition, high doses of electrons produce cross‐linking and insolubilization of the resin.