Pressure dependence of photoresist removal rate using hydrogen radicals

Abstract

Photoresists play a key role in lithography processes for the fabrication of electronic devices, but must be removed after processing. The removal method using hydrogen radicals, which are produced on a tungsten hot-wire catalyst, is effective to resolve some environmental and industrial problems in usual methods. However, the removal rate is not as good as that of the usual methods. We have previously described that the removal rate is enhanced just by decreasing Hydrogen pressure but the rate limitations not clarified. In present study, we examined the removal rate dependence on the pressure and revealed that the upper limitation of the enhancement is achieved at 0.50 Pa. The removal rate at 0.50 Pa was 8.3 times higher than that at 20 Pa when the surface temperature was 250 °C.