Lithographic imaging-driven pattern edge placement errors at 10nm node

Abstract

Demand for ever increasing level of microelectronics integration continues unabated, driving the reduction of the integrated circuit critical dimensions, and escalating requirements for image overlay and pattern dimension control. The challenges to meet these demands are compounded by requirement that pattern edge placement errors be at single nanometer levels. Layout design together with the patterning tools performance play key roles in determining location of the pattern edges at different device layers. However, complexities of the layout design often lead to stringent tradeoffs for viable optical proximity correction and imaging strategy solutions. As a result, in addition to scanner overlay performance, pattern imaging plays a key role in the pattern edge placement. The imaging contributes to edge displacement by impacting the image dimensions and by shifting the images relative to their target locations. In this report we discuss various aspects of advanced image control at 10 nm integrated circuit design rules. We analyze the impact of pattern design and scanner performance on pattern edges. We present an example of complex, three step litho-etch patterning involving immersion scanners. We draw conclusion on edge placement control when complex images interact with wafer topography.