Kinya Usuda

Highly Sensitized Electron-Beam Resist By Means Of A Quenching Process

It was found that the sensitivity of poly(2,2,2-trifluoroethyl-a-chloroacrylate) (EBR-9) is greatly enhanced to around 0.1μC/ci when EBR-9 is quenched at 160°C/sec after baking. This sensitivity is about 27 times higher than that obtained by cooling at 65t/min in an atmosphere of still air. This result indicates that the sensitivity of an electron-beam resist depends on the cooling rate. In particular, a change in the cooling rate within the glass-transition region of EBR-9 leads to a drastic change in sensitivity. One method of thermal analysis, differential scanning calorimetry(DSC), made it clear that the slower the resist is cooled through the glass-transition region, the more enthalpy relaxation is produced. Furthermore, it was proved that a resist with much reduced enthalpy indicates a lower solubility rate, and that the annealing method was valid to estimate the reduced enthalpy using DSC. It is concluded that the quenched resist becomes more sensitive as a result of the enhanced solubility because of little enthalpy relaxation.