Haze and pellicle material selection for haze free

The problem of haze occurrence in photolithography is one of the most important problems in the lithography industry. Understanding the conditions and mechanisms that generate haze defects provide important clues for preparing pellicle, photomask, and lithography environments for haze-free photolithography. In the pellicle industry, self-help efforts are being made to reduce the contribution of pellicles to haze occurrence, but haze occurs in the complex causal relationship of pellicles, photomasks, and lithography (fab environments). Therefore, haze reduce is difficult to solve with pellicle industry's efforts only. In this paper, we investigated microscopic images and occurrence mechanisms of haze defects formed from actually suspected chemicals, IC results of sulfate and ammonium ions, ArF light (excimer laser) resistance of anodized and new frame, also summarized the results of haze occurrence from previous research, and examined the occurrence pattern and location according to haze cause. Based on this, we propose the pellicle solution to control the haze reduction such as material selection of pellicle.