| Popis: |
The key challenge to enable a good defectivity control for extreme ultraviolet (EUV) single expose at 32nm pitch is to understand what are the main drivers for defect generation. CD is one of the main contributors, and has many sources of variability (reticle, imaging, die layout, scanner). The paper will first discuss the quantification of defectivity sensitivity to CD, and identification of the main sources of CD variations (EUV flare, black border, etch, APC, mask bias etc...). All those effects do not have the same consequences on the defect level (only nanobridges will be considered as they are the main defect type). At this pitch, CD margin is becoming critical, an any small variation can lead to pattern collapse/bridge regime. In a second part, we will discuss the different options for a better CD control and evaluate their impact on the overall defectivity level (reticle, process and tool will be considered). An Intrafield CD uniformity improvement of 40% can lead to a defect density reduction by about 30%. |
