19 March 2015 The analysis method of the DRAM cell pattern hotspot
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It is increasingly difficult to determine degree of completion of the patterning and the distribution at the DRAM Cell Patterns. When we research DRAM Device Cell Pattern, there are three big problems currently, it is as follows. First, due to etch loading, it is difficult to predict the potential defect. Second, due to under layer topology, it is impossible to demonstrate the influence of the hotspot. Finally, it is extremely difficult to predict final ACI pattern by the photo simulation, because current patterning process is double patterning technology which means photo pattern is completely different from final etch pattern. Therefore, if the hotspot occurs in wafer, it is very difficult to find it.

CD-SEM is the most common pattern measurement tool in semiconductor fabrication site. CD-SEM is used to accurately measure small region of wafer pattern primarily. Therefore, there is no possibility of finding places where unpredictable defect occurs. Even though, "Current Defect detector" can measure a wide area, every chip has same pattern issue, the detector cannot detect critical hotspots. Because defect detecting algorithm of bright field machine is based on image processing, if same problems occur on compared and comparing chip, the machine cannot identify it. Moreover this instrument is not distinguished the difference of distribution about 1nm~3nm. So, "Defect detector" is difficult to handle the data for potential weak point far lower than target CD.

In order to solve those problems, another method is needed. In this paper, we introduce the analysis method of the DRAM Cell Pattern Hotspot.
© (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Kyusun Lee, Kyusun Lee, Kweonjae Lee, Kweonjae Lee, Jinman Chang, Jinman Chang, Taeheon Kim, Taeheon Kim, Daehan Han, Daehan Han, Aeran Hong, Aeran Hong, Yonghyeon Kim, Yonghyeon Kim, Jinyoung Kang, Jinyoung Kang, Bumjin Choi, Bumjin Choi, Joosung Lee, Joosung Lee, Jooyoung Lee, Jooyoung Lee, Hyeongsun Hong, Hyeongsun Hong, Kyupil Lee, Kyupil Lee, Gyoyoung Jin, Gyoyoung Jin, "The analysis method of the DRAM cell pattern hotspot", Proc. SPIE 9424, Metrology, Inspection, and Process Control for Microlithography XXIX, 94241D (19 March 2015); doi: 10.1117/12.2084992; https://doi.org/10.1117/12.2084992

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