Nanoimprint lithography is a candidate for lithography for the hp32nm and hp22nm nodes. Molds or templates for it are being developed on the basis of the process of making phase-shift photomasks. The combination of a 50 kV-VSB (variable shaped beam) EB writer and a chemically amplified resist (CAR) does not have a resolution sufficient for 1X patterning. On the other hand, a combination of a 100 kV-SB (spot beam) EB writer and a non-CAR satisfies the resolution requirement, but this combination leads to an extremely low throughput due to low resist sensitivity.To increase the throughput, we have examined double patterning and double exposure with hybrid use of two different types of writers, a 50 kV-VSB writer, JBX-9000MV, for delineating fine features and a 100 kV-SB writer, JBX-9300FS, for delineating rough features. Overlay accuracy is a key item in such hybrid writing. The results of an overlay accuracy evaluation together with a throughput improvement will be reported in this paper. An estimation of the time for writing a gate layer has given a good example; the writing time for hybrid writing is reduced to about half of the time for 100kV-SB writing. The overlay accuracy for double patterning is found to be 20nm (3σ). However, we are confident that we will be able obtain an overlay accuracy of 10nm (3σ) by improving the image placement accuracy of the JBX-9300FS. An example of double exposure is also shown.
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