Scatterometry Characterization of Spacer Double Patterning Structures

DPT overlay errors result in CD distortions and CD non-uniformity leads to overlay errors demanding increased critical dimension uniformity (CDU) and improved overlay control. Scatterometry techniques are used to characterize the CD uniformity, focus and dose control. We will present CD distribution (CDU) and profile characterization for spacer double patterning structures by advanced scatterometry methods. Our result will include NISR, and spectroscopic ellipsometry (SE) characterization of CDU sensitivity in spacer double patterning stack. We will further show the results of spacer DP structures by NISR and SE measurements. Metrology comparison at various process steps including litho, etch and spacer and validation of CDU and profile; all benchmarked against traditional CDSEM measurements.