Most of simulation tools and OPC engines use Kirchhoff (thin mask) approximation for imaging calculation. Some commercial simulation tools have implemented the rigorous algorithm to solve the Maxwell's equations for the electric and magnetic fields. Currently, a rigorous algorithm is being used for the case of high topographical mask such as CPL and alternating PSM. However, the mask topographical effect of binary mask and attenuated PSM is not negligible in the case of hyper NA lithography. Implementing the rigorous algorithm on full chip OPC is impractical due to its OPC runtime limitation. Thin mask and rigorous simulation modeling are compared to check whether the current algorithms of OPC tools can sufficiently reflect the mask topography effect of hyper NA lithography and whether a combination of currently usable algorithms can cover the mask topography effect. OPC modeling is generally executed based on measured CD data. However we do not have usable hyper NA scanners, so the OPC modeling is executed based on full physical simulation data to the resist image, which we will define as a "Virtual OPC modeling".
[1]
Chris A. Mack,et al.
The impact of mask topography on binary reticles at the 65-nm node
,
2004,
SPIE Photomask Technology.
[2]
Peter De Bisschop,et al.
Mask and wafer topography effects in immersion lithography
,
2005,
SPIE Advanced Lithography.
[3]
Andrew R. Neureuther,et al.
Simplified models for edge transitions in rigorous mask modeling
,
2001,
SPIE Advanced Lithography.
[4]
Konstantinos Adam.
Modeling of electromagnetic effects from mask topography at full-chip scale
,
2004,
SPIE Advanced Lithography.
[5]
Andreas Erdmann,et al.
Mask modeling in the low k1 and ultrahigh NA regime: phase and polarization effects (Invited Paper)
,
2005,
Other Conferences.