Ion-Bombardment-Induced Improvement of Photoresist Mask Properties for RF Sputter-Etching

This is the authors' abstract. We don't add key points for this paper.

Ion-bombarded photoresists were found to have improved mask properties for sputter-etching. The photoresist bombarded with Ar ions with an intensity of the order of 10 15 ions cm -2 has a smaller etching rate than the unbombarded photoresist and shows no traces of thermoplastic flow and no surface morphology degradation, even when it is sputter-etched without any intentional thermal contact, which is often made for preventing the photoresist mask degradation. Although reduction in the photoresist pattern dimensions and in the photoresist removal rate by the oxygen plasma ashing technique occurs when the photoresist is ion-bombarded, it is confirmed that these drawbacks do not impede the application of the improved photoresist. Delineation of fine gold patterns for an absorber for an X-ray lithography mask is demostrated as an example of the application of the improved photoresist mask for sputter-etching.