Photolithography (Lithography)

Photolithography is to make device patterns on the surface of semiconductor substrate. During photolithography, ultraviolet light passes through the pattern windows of the mask, and the intensity that the photoresist receives is uniform. This chapter discusses the lithography process. In the lithography process, the design of photomask is also an important topic. The chapter focuses on the alignment mark on the mask used for manual alignment. Several points need to be considered in the design of the alignment mark, which are often encountered in university laboratories and clean rooms. To avoid absorption, the light system of an extreme ultraviolet lithography machine adopts a reflective mirror structure, and the photomask also adopts this structure. The optical system is placed in a vacuum chamber, and the wafer and the mask are also placed in a vacuum chamber.