Fabrication of a multi-level lens using independent-exposure lithography and FAB plasma etching

Micro lenses are needed for slim micro optical systems. A multi-level lens can be adapted to satisfy the requirements for a thin lens. Several techniques can be employed to produce multi-level lenses, including microelectromechanical system processes, laser fabrication, and mechanical manufacturing. In this study, a method involving independent-exposure lithography and fast atom beam plasma etching is presented for the fabrication of a multi-level lens. The advantages of the method are a non-repetitive process and precise fabrication due to the principle of independent exposure in the electron beam lithography process. The designed and produced multi-level lens reveals a four-level staircase, and has a focal length of 714.5 μm, a thickness of 0.723 μm, and a minimum width of 0.966 μm.