Process-induced wafer distortion: its measurement and effects on overlay in stepper-based advanced lithography

摘要

Abstract: The distortion introduced by some manufacturing stepson wafers can sometimes have a strong effect on overlayresults. Thermal processes, for example, can introducewafer distortions that cannot be completely compensatedby the stepper alignment system with a consequentdegradation in overlay. A new methodology which canmeasure the process induced distortion on wafers(exposed with a stepper system) at different steps in astandard process flow has been developed and isdescribed in this paper. This method does not requireany external metrology instruments apart from astandard precision stepper and the method is compatiblewith all process layers. Experimental results ofapplication of the method on manufacturing process arepresented. !10