Recent progress of materials and processes for EUV lithography. Ready for HVM? (Conference Presentation)

Abstract

Extreme ultraviolet (EUV) lithography is considered to be the most effective strategy for realize 7 nm generation manufacturing and beyond. With recent rapid progress on the source power improvement, process and material explorations are more and more accelerated to achieve HVM requirements. Therefore, a key factor for the realization of EUV lithography is the choice of EUV resist material that is capable of resolving below 15-nm half pitch with high sensitivity. It has been thought that the main challenge of EUVL is satisfying Resolution (R) – LWR (L) – Sensitivity (S) requirements simultaneously. On the other hand, recent reports indicate defectivity caused by stochastic effect have to consider as well as RLS-tradeoff improvement. For 7 nm node application, traditional chemically amplified resist (CAR) system is first candidate because of its well-studied property through KrF and ArF manufacturing process for many years, e.g. stability, metal contamination and post-litho process compatibility. However its low EUV absorption property enhancing photon-shot-noise (PSN) effect is one major disadvantage of conventional CAR system, especially for low dose resist process construction. In the past, several researches aiming high EUV absorption CAR system were reported, but material design and its lithographic performance still need detailed investigation. The present study aims to clarify how we can overcome RLS-tradeoff and reduce defects. Accordingly, we investigated the PSN effect using progress dependency study and material design requirements to achieve high EUV absorption resists. Lithographic results of high EUV absorption resists based on the study were also described.