The tight process window of advanced lithography in the semiconductor industry is further challenged by the growing contribution of photo-mask related CD variations [1]. In previous technology generations, global measurement and global correction were sufficient to compensate for critical dimension uniformity (CDU) variations deriving from various sources. However, in the low K 1 regime for 45nm nodes and below, cross-coupled effects such as Mask Error Enhancement Factor (MEEF) and mask CDU can easily consume the overall CD budget related to lithographic process steps (see table 3).ASML's DoseMapper was designed to correct system (e.g. scanner, track) and non-system (e.g. mask) related errors [2] controlled by an Automated Process Control (APC) system. It was introduced as a method for correcting intra-field and inter-field variations, relying on feedback from printed wafer based metrology. Here we propose using AMAT's IntenCD TM map for supplying dense CDU measurement results from the reticle as a feed-forward input to DoseMapper. The IntenCD TM application characterizes CD uniformity of 'features of interest' across the mask in the form of a dense map with high accuracy and throughput.The case studies presented in this paper are the result of collaboration between AMAT and ASML to demonstrate the benefit of feeding IntenCD output into DoseMapper CD analyzer which translates the mask CD map into a scanner dose recipe.The integrated solution can be implemented in manufacturing factories to shorten turnaround time and improve the exposure process window. It can be used to compensate for CDU effects due to mask production as well as contributions due to life time deterioration.

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In this paper we compare the imaging properties of lithographic test structures formed on test masks with different reticle absorbers for use in1.35 NA immersion lithography. We will look into different aspects like process windows and CD fingerprints. Beyond that we look into the topographic effects caused by the different absorbers, the mask 3D effects. We will study the interaction between the different masks and immersion scanner. Special attention is given towards the correctability of the intrafield CD fingerprint by mask and scanner applying dose corrections.

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