Latest ArF light source with speckle reduction technology for immersion lithography improving chip yield

Chipmakers have used cross-platform of both EUV exposure and ArF immersion multi-patterning exposure depending on cost effectiveness at each layer. ArF immersion exposure has been required lower linewidth roughness(LWR) to reduce cross matched machine overlay(xMMO) which is the overlay between the different platforms. ArF light sources essentially produce speckle as non-uniform intensity distribution resulting from interference effects generated within a beam. It leads to increase LWR, which results in increasing xMMO. The latest ArF immersion light source, GT66A is introduced a new optical pulse stretcher(OPS) that increases pulse duration to reduce speckle by 30% to improves LWR, which reduces xMMO. This technology will improve chip yield for chipmakers in the processes mixed ArF immersion exposure and EUV exposure.