Resists for Helium Ion Beam Lithography: Recent Advances

Since the fabrication of micro-/nanoelectronic devices are marching toward ultralow node technology with dense patterns to meet the current industry demands, continuous advancement is needed in terms of material design and lithographic techniques. In this perspective, helium ion beam lithography (HIBL) has gained tremendous attention of the scientific society to realize high-performance device fabrication with advanced technology. Salient features of the helium ion beam including sub-nanometer spot size, high-intensity lighter ion (with respect to gallium and neon ions) make the HIBL technique a competitive next-generation lithography tool. This review describes, in brief, the significance of HIBL technology in comparison with electron beam lithography (EBL); however, it presents in detail the development made in the area of resists for HIBL. One of the important characteristics of He+ beam is, reduced backscattering leads to minimizing the proximity effects in contrast with EBL. Furthermore, it emphasizes the developments of various resist materials to perform high-resolution patterns at comparable line-edge roughness/line-width roughness (LER/LWR) values. HIBL performances of various classes of materials are presented here to give a overall conception of the technique. The materials including organic, inorganic, organic-inorganic hybrids, and nanoscale materials which have shown promising patterning under He+ beam irradiation have been included and discussed in this work.