Abstract
This paper describes mask topography effects of alternating phase shift masks for DUV lithography. First two options to achieve intensity balancing are discussed. Global phase errors of +-10° cause a CD change of 3 nm and 8 nm CD placement errors. The CD placement appears to be the parameter affected most by phase errors. A sloped quartz edge with an angle of 3° causes a CD change of 10 nm. The CD sensitivity on local phase errors, i. e. quartz bumps or holes was also studied. The critical defect size of a quartz bump was seen to be 180 nm (5 x) for 150 nm technology. For the investigation the recently developed topography simulator T-Mask was used. The simulator was first checked against analytical tests and experimental results.