Binary Mask Defect Printability for 130-nm ArF Lithography

摘要

Recent observations indicate that wafer CD control for the 0.13-μm node is sensitive to non-phase defects between 0.1 μm and 0.25 μm on a 4X reticle, as a function of the location of the sub-killer defect. Since more and more small defects can be detected by today's advanced mask defect inspection tools, it is important to determine whether these detected defects can impact wafer lithography process window. The experimental result is based on a typical 0.13-μm process using a pre-designed Defects Sensitivity Monitor (DSM) reticle to address the printability of these programmed defects. The defects in different pattern density areas behave differently on printed wafers. The location of sub-killer defects affects wafer CD variation. Greater than 10% CD error was found for clear defects on chrome features such as a 180-nm bump and 220-nm divot. The location of chrome defects on clear area is also critical. If the defect is located unfavorably, a 180-nm isolated spot defect produces more than 10% CD error. We also found that CD error is most sensitive to defects appeared on dense main features such as bump and divot, but not so sensitive with a neighboring chrome spot as long as the chrome spot is well separated away the main feature. In addition to printability, experimental results showing CD variation as a function of defect size and location quantitatively will be presented. Hence, DSM reticle has been shown to be effective in characterizing CD error sensitivity and in setting up defect inspection criteria for reticle quality control.