Resist reflow for 193-nm low-K1 lithography contacts

Contact patterning for advanced lithography generations is increasingly being viewed as a major threat to the continuation of Moore's Law. There are no easy patterning strategies which enable dense through isolated contacts of very small size. Lack of isolated contact focus latitude, high dense contact mask error factor and incredibly low defectivity rate requirements are severe issues to overcome. These difficulties mean that new and complex patterning methods for contacts at the 90nm and 65nm device generations are being considered. One possible option for improving the process window of contact patterning is resist reflow. Resist reflow can supplement almost any other optical extension method for contact lithography. Previous results have shown the significant benefits of this method for CD control on semi-dense and isolated contact for the 100nm device generation. This work extends the previous work by investigating very dense pitch through isolated contact patterning at 193nm low K1 lithography regimes. The encouraging overall CD control and process window of reflowed contacts using the ARCH TIS2000 bilayer resist system is analyzed through pitch for different imaging options. An investigation of the capability of resist reflow in combination with optimized reticle and illumination for the 65nm device generation is also presented as are details of defectivity levels for reflowed contacts on 90nm device products.