The simulation of application of high transmittance AttPSM for sub-100 nm pattern in 248 nm lithography

In contrast to the normal transmittance (T < 10%) attenuated phase-shifting mask (AttPSM), the high transmittance AttPSM assisted with Cr scattering bars could enhance the resolution of aerial image down to about 0.1 mum isolated line in clear-field mask. With transmittance T = 35% of the 0.1-mum isolated line as embedded layer, the optimized width of scattering bars is 0.085 mum, the distance between Cr scattering bar and 0.1 mum isolated line is 0.205 mum, and DOF is 0.53 Rm under the optimized quadrupole illumination with 0.51/0.27 (sigma (offset)/sigma (radius)). Compared to transmittance 5 and 15% of embedded layer, the negative and positive factors of mask error enhancement factor (MEEF) could be kept in the range of - 2 to + 2 for isolated lines wider than 80 mum at transmittance 35%, assisted with the 0.085-mum width of Cr scattering bars. (C) 2001 Published by Elsevier Science B.V.