Investigation of the effects of bottom anti-reflective coating on nanoscale patterns by laser interference lithography

Enhanced resolution of the structures can be achieved by employing the bottom anti-reflective coating (BARC) material in laser interference lithography process. The purpose of the BARC is to control the reflection of light at the surface of the wafer to minimize the effects caused by reflection. Lloyd's mirror interferometer is utilized for the experiment with 257 nm wavelength Ar-Ion laser used as the light source to generate one-dimensional nanoscale patterns. By adjusting reflectivity through application of the BARC material, scattering of the patterns are reduced. The effects of BARC material are explored to confirm the reduction of the vertical standing wave, which is the main cause of undesirable nanoscale patterns. It is also highlighted that improvements through utilization of BARC material enables smaller pattern size with a set pitch size by controlling the exposure energy.