Evaluation of IDEALSmile for 90 nm FLASH Memory Contact Holes Imaging with ArF Scanner

According to sizes dictated by ITRS roadmap, contact holes are one of the most challenging features to be printed in the semiconductor manufacturing process. The development of 90 nm technology NOR FLASH memories requires a robust solution for printing contact holes down to 100 nm on 200 nm pitch. The delay of NGL development, as well as open issues related to 157 nm scanner introduction, pushes the industry to find a solution for printing such tight features using existing ArF scanner. IDEALSmile (Innovative Double Effective source Aided Lithography with Single Mask Implemented Lithographic Enhancement) technology from Canon was proven to be a good candidate for achieving such high resolution with sufficiently large through pitch process window using a binary mask, relatively cheap and simple to be manufactured, modified illumination, single exposure, without any negative impact on throughput and no increase of cost of ownership. This paper analyses main issues related to the introduction of this new resolution enhancement technology on a real FLASH memory device, highlighting advantages as well as known problems still under investigation.