Characterization and removal of contaminants in lithography

Photolithography is a foundational technique for manufacture compact chips in semiconductor industries. Regulating and cleaning contaminants in lithographic processes are crucial for achieving the higher resolution and smaller feature sizes, which contain a variety of physical phenomena related to fluid dynamics. In this review, we will first introduce the basic principles of two mainstream lithography, namely deep ultraviolet (DUV) lithography and extreme ultraviolet (EUV) lithography. We critically review several types of contaminants such as droplets, bubbles, particles and chemical organic pollutants, highlighting the advanced techniques for identifying the nano-substances and fluid behaviours. Then the control strategies for mitigating contaminants are reviewed, especially for the contamination removal on photomask, the improvement on the purity of immersion liquid and efficient cleaning treatment for wafer surface. This review underscores the critical need for advanced contaminant management strategies in photolithography, integrating innovative cleaning techniques that promise to elevate lithographic performance and drive future developments in semiconductor technology.