Abstract
Line-edge roughness (LER) characterization is vital in modern semiconductor industry. An EKEI (enhanced knife edge interferometry)-based method for photomask LER characterization, being capable of a 0.01μm LER measurement accuracy, was proposed in this paper. The changes in fringe pattern caused by edge roughness were derived and analyzed through cross-correlation index. A negative relationship between the cross-correlation and the LER value was observed. The results are validated by both simulation and experiment, indicating that the proposed method can detect both roughness changes and residual pollution on photomask edge.
Volume Subject Area:
Manufacturing Processes
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