Defect Printability Studies at SEMATECH Il-Yong Jang* a , Ranganath Teki a , Vibhu Jindal a , Frank Goodwin a Masaki Satake b , Ying Li b , Danping Peng b Sungmin Huh c , Seong-Sue Kim c a SEMATECH, 257 Fuller Road Suite 2200 Albany, NY 12203 USA b Luminescent Technologies, Inc., 2300 Geng Road, Suite 250, Palo Alto, CA 943032 c Semiconductor R&D Center, Samsung Electronics Co., LTD., San#16 Banwol-Dong, Hwasung-City, Gyeonggi-Do, 445-701 Korea ABSTRACT We describe SEMATECH’s recent defect printability work categorizing native phase defects by type and dimension using a NXE3100 EUV scanner and DPS (Defect Printability Simulator) software developed by Luminescent Technologies. Since the critical dimension (CD) error on a wafer simulated by the DPS is strongly affected by the multilayer (ML) geometry, it was very important to select the optimal multilayer (ML) growth model for each defect. By investigating the CD results obtained from 27 nm HP node imaging on NXE3100 and comparing those with simulation results, it was clear that reconstructed ML geometry generated by the AFM measurement showed much better simulation accuracy than conformal ML geometry. In order to find a typical ML growth model to predict the best ML geometry for a given dimension and height of defect, we calibrated a general ML growth model with AFM data and obtained ML growth model parameters. Using the fitted ML geometry generated from ML growth model parameters, CD error for 22 nm HP node was simulated and the result showed that conformal ML geometry is good for 24 nm defect simulation while not appropriate for 36 nm defect simulation. Keywords: EUV mask, defect printability, phase defect, printability simulation, multilayer growth model 1. INTRODUCTION As extreme ultraviolet (EUV) lithography technology has matured, patterning quality using current EUV exposure tools is improving. However challenges in the mask defect and review infrastructure may slow the introduction of EUV lithography to mass production. While the number of phase defects on EUV mask blanks has been decreasing noticeably through the efforts of mask blank suppliers, the defect levels of EUV mask blanks require further improvement. SEMATECH has studied EUV defect printability using programmed pit and bump defects imaged by the actinic inspection tool (AIT) at Berkeley and has shown how the critical spherical equivalent volume diameter (SEVD) of the defect affects printability under different exposure conditions [1]. However, because these studies used programmed defects on EUV blanks, they could not predict most cases of defect printability in EUV high volume manufacturing (HVM) since HVM masks are affected by native phase defects under the absorber pattern. Recent study showed that blank defects which are 23 nm in SEVD could be detected by the most advanced optical inspection tool and the defects start to be printed at 22 nm HP node [2], however it is not easy to predict the real defect printability using SEVD alone, because native defects have various sizes and shapes even though they have the same SEVD. Furthermore it is very difficult to estimate the defect printability of native defects using only simulation software because geometry of the ML strongly depends on the defect diameter. ML geometry should be selected carefully to assure simulation accuracy. Therefore we must know how phase defect size increases as ML stacks are added. Although real ML geometry would provide the most accurate information about which geometry should be used for simulation, it is cost-prohibitive to break a production mask just to get the cross section image. Therefore it is necessary to have quantified data indicating which ML geometry is the best to use as a simulation input parameter for various phase defect diameters. Accordingly, SEMATECH has started a new project to investigate the printability of native phase defects on pattern masks using state- of-the-art commercial mask manufacturing tools, SEMATECH’s own failure analysis (FA) tools and DPS software. Based on the defect libraries created during last two years [1] and actinic printing results obtained from NXE3100 exposure, the results of native defect printability and its relationship with ML geometry will be presented in this paper. *mason.jang@sematech.org; phone +1-518-649-1119; fax +1-518-649-1344 Photomask and Next-Generation Lithography Mask Technology XX, edited by Kokoro Kato, Proc. of SPIE Vol. 8701, 870111 · © 2013 SPIE CCC code: 0277-786X/13/$18 · doi: 10.1117/12.2028069 Proc. of SPIE Vol. 8701 870111-1 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 09/16/2013 Terms of Use: http://spiedl.org/terms