Progresses on new generation laser direct writing technique

Laser direct writing (LDW) system is a maskless, highly efficient, and cost-effective micro-/nanofabrication tool and has been widely used in many fabrication fields such as Micro-Electro-Mechanical System (MEMS), photomask, various micro-/nanostructures, and so forth. With rapid development of nanotechnologies, LDW system with higher fabrication resolution and more application scenarios has been evoking interest. In recent years, New-Generation LDW (New-Ge LDW) system has been developed for meeting requirements mentioned above and has already provided many opportunities to explore new micro-/nanofabrication technologies. The New-Ge LDW system improves fabrication resolution based on a new working principle of laser-matter non-linear interaction, which is quite different from traditional LDW that is limited to Rayleigh's criterion. The new principle brings two technical breakthroughs: (1) exceeding limitation of diffraction limit (Rayleigh's criterion) realizing nanoscale fabrication; (2) breaking through limitation of single acceptor material (organic photoresist) enabling any material to be as resist materials such as metals, semiconductors, organic materials, and so forth, thus greatly expanding usage scenarios of the New-Ge LDW. Many works have exhibited that the New-Ge LDW has tremendous potential in fabrication of various nanodevices and nanostructures for different material systems. It is necessary and urgent to review the New-Ge LDW from principle to equipment and to technological methods and latest applications.