Probing defects in metal oxide resists with an electrical yield vehicle

The industry is currently undergoing a transition from low-NA to high-NA EUV lithography. Metal Oxide Resists (MORs) will play an important role in extending the operating point of high-NA scanner to tight pitch. Understanding the impact that lithographic parameters of metal oxide resists have on the performance of high-NA relevant line/space pitches is mostly unknown. We have observed that the lithographic performance of a metal oxide resist differs significantly depending on the choice of underlayer, post-exposure-bake (PEB), and development technique. Developing an electrical defectivity vehicle that can assess both resist breaks and bridges and can be responsive to lithographic changes, overcomes the limitations of conventional e-beam or optical inspection-based defect metrology. In this presentation, we have assessed the impact that parameters such as underlayer, post-exposure-bake (PEB), and development optimization have on electrical yield for pitch 26 metal lines both for the current 0.33 NA EUV scanner, as well as the 0.55 NA EUV scanner.