True metrology with reduced resist shrinkage effect for process window optimization and EUV stochastic effects analysis

As semiconductor technology progresses toward smaller nodes, the precision and accuracy of metrology have become increasingly critical, particularly in extreme ultraviolet (EUV) lithography. True metrology is essential due to the challenges posed by shrinking resist dimensions and thickness, where resist shrinkage constitutes a larger proportion of the overall measurement error. This effect introduces inaccuracies across various pattern structures within logic layouts, making it necessary to mitigate shrinkage for reliable process control. Accurate metrology is especially crucial in evaluating the process windows of After Develop Inspection (ADI) and After Etch Inspection (AEI), both of which are vital for ensuring robust manufacturability. Determining the best focus is critical in smaller dimensions, as resist shrinkage can shift the perceived optimal focus, leading to inaccuracies. Frequency-based Line Edge Roughness (LER) analysis plays a crucial role in defining this accurate best focus, as it aligns well with low-shrinkage ADI critical dimensions (CDs). Additionally, the resist profile and smaller pixel analysis are instrumental in understanding and mitigating EUV stochastic effects. By integrating these advanced analytical techniques, this study aims to enhance the reliability of metrology, optimize process windows, and improve process control in advanced semiconductor manufacturing.