Articles you may be interested inFocused helium and neon ion beam induced etching for advanced extreme ultraviolet lithography mask repair Infinitely high selective inductively coupled plasma etching of an indium tin oxide binary mask structure for extreme ultraviolet lithography Improvement of imaging properties by optimizing the capping structure in extreme ultraviolet lithography Among the core extreme ultraviolet lithography ͑EUVL͒ technologies, mask fabrication is of considerable importance due to the use of new reflective optics having a completely different configuration from that of conventional photolithography. This study investigated the etching properties of attenuated phase-shift mask materials for EUVL, such as TaN ͑attenuator layer͒, Al 2 O 3 ͑spacer͒, Mo ͑phase shifting layer͒, Ru ͑buffer/capping/etch-stop layer͒, and Mo-Si multilayer ͑reflective layer͒ by varying the Cl 2 / Ar gas flow ratio, dc self-bias voltage ͑V dc ͒, and etch time in inductively coupled plasmas. For the fabrication of the attenuated EUVL mask structure proposed herein, the TaN, Al 2 O 3 , and Mo layers need to be etched with no loss of the Ru layer on the Mo-Si multilayer. The TaN and Al 2 O 3 layers were able to be etched in BCl 3 / Cl 2 / Ar plasmas with a V dc of −100 V and the Mo layer was etched with an infinitely high etch selectivity over the Ru etch-stop layer in a Cl 2 / Ar plasma with a V dc of −25 V even with increasing overetch time.

Currently, extreme ultraviolet lithography (EUVL) is being investigated for next generation lithography. Among the core EUVL technologies, mask fabrication is of considerable importance due to the use of new reflective optics with a completely different configuration than those of conventional photolithography. This study investigated the etching properties of indium tin oxide (ITO) binary mask materials for EUVL, such as ITO (absorber layer), Ru (capping/etch-stop layer), and a Mo–Si multilayer (reflective layer), by varying the Cl2/Ar gas flow ratio, dc self-bias voltage (Vdc), and etch time in inductively coupled plasmas. The ITO absorber layer needs to be etched with no loss in the Ru layer on the Mo–Si multilayer for fabrication of the EUVL ITO binary mask structure proposed here. The ITO layer could be etched with an infinitely high etch selectivity over the Ru etch-stop layer in Cl2/Ar plasma even with a very high overetch time.