Feasibility study of an embedded transparent phase-shifting mask in ArF lithography

We have proposed the combination of the new transparent phase-shifting mask with the off-axis illumination, and have carried out the feasibility study on it, for the objective of the extension in optical lithography. We have demonstrated that 0.10 mu m line pattern fabrication is achieved with sufficient process margin by applying the transparent phase-shifting mask to ArF lithography. Especially, this new technology is characterized that the resolution of isolated line pattern is more strongly enhanced as compared with other resolution enhancement technologies, the combination of the attenuated phase-shifting mask with the off-axis illumination and the alternating phase-shifting mask technology. However, the application of the transparent phase-shifting mask is restricted within limited pattern size less than about 0.15 mu m. For applying this new technology to actual logic device patterns, we have also proposed the embedded transparent phase-shifting mask in which the transparent phase shifter and the opaque layer are assigned to the fine features and the larger features, respectively. In the next stage, we will. study the application to logic device patterns.