Extreme ultraviolet (EUV) lithography faces major challenges for smaller nodes due to the impact of stochastic and processing failures.1 One of the main challenges for pitch shrink at these nodes is the optimization of the trade-off between break type defects versus bridge type defects as the process window between these defect modes gets smaller.2 In this paper, we examine EUV defect reduction techniques for Chemically Amplified Resist (CAR) and Metal Oxide Resist (MOR) via coater/developer process development combined with optimized etching processes.
We demonstrated a high selective and anisotropic plasma etch of Si3N4 and SiC. The demonstrated process consists of a sequence of ion modification and chemical dry removal steps. The Si3N4 etch with H ion modification showed a high selectivity to SiO2 and SiC films. In addition, we have developed selective etch of SiC with N ion modification. On the other hand, in the patterning etch processes, the fabrication of multi-layer films requires the precision of atomic scale XY CD controllability in complex hole patterns. In order to solve the requirement, we have developed Advanced Quasi- Atomic Layer Etching (ALE) technology which achieved X-Y CD control in oval patterns, along with a wider X-Y CD control margin. Furthermore, in the memory fabrication process, it is required to vertically etch the organic film mask pattern in high aspect ratio (A/R) feature. Therefore, we have developed a new approach that combines atomic layer deposition (ALD) technique and organic film etch process. With this method, we are able to achieve the vertical mask profile. Thus, we will show that these new process technologies have a significant potential to solve critical challenges in the various processes in advanced nodes.
In patterning etch processes, the fabrication of multilayer films requires the precision of atomic scale X-Y CD controllability in complex hole patterns, and reduction of local variability such as Line Edge Roughness (LER), Line Width Roughness (LWR) and Local CDU (LCDU). In order to solve these requirements, we have developed Advanced Quasi-ALE technology which achieved reduction of LCDU, along with a wider X-Y CD control margin. In this paper, we introduce the three benefits of our atomic scale CD and variability control process technology; (1) XY CD control in oval patterns, (2) LCDU reduction and (3) wider etching window using Advanced Quasi-ALE technique. Hence, we will show that it has a significant potential to solve critical challenges in the patterning processes of N5 and beyond.