Different approaches to overcome existing limits in optical micro and nanometrology

Abstract

Modern  products  are  becoming  more  miniaturised,  more  complex  and  have  an increasing  number  of  functionalities.  The  critical  dimensions  of  structures  written in silicon  are  becoming  considerably  smaller  than  the  wavelength  of  the  applied light source and this trend is to be sustained for the coming years until the next -generation patterning  with  extreme  UV  light  is  used  in  practice.  As the feature sizes are decreasing, so the theoretical and practical constraints of making them and ensuring their quality are increasing. The same holds true for other industrial branches such as machine  construction  and  automotive  engineering  where  the  surface-quality requirements of critical components and the overall complexity of the products have dramatically  grown  over  the  past  few  years. Consequently, modern production and inspection technologies are confronted with a bundle of challenges. In this paper we first  discuss  the  challenges  to  optical  measurement  techniques  and  their  physical limitations. Afterwards some modern approaches are discussed such as active wave front control, model based metrology and multi -scale sensor fusion. On example of the inspection of non-resolved semiconductor structures and micro components we present new practical ways to cope with the mentioned challenges.