| Popis: |
As the extreme ultraviolet (EUV) lithography technology progresses towards and below sub-7nm generations, polarization effects will begin to have an impact. As numerical apertures increase, the consequences at both the mask and the wafer plane need to be understood. Contrast losses at large angles can occur from non-ideal interference at the wafer plane (i.e. TM vs. TE polarization). While such loss of infidelity can be low for near wavelength half-pitch generations, additional image degradation can be attributed to polarization effects for higher resolution generations. Some of this arises from the mask. The polarized reflectance from a EUV photomask is influenced by the multilayer reflective stack as well as the polarizing effect of the patterned features. This paper explores the polarization effects that are induced by EUV masks for sub-7nm lithography generations. From the results, it was found that there is polarization-dependent induction and attenuation of current in EUV mask structures as mask pitch decreases. |
