Improvements in the imaging performance of a high volume manufacturing EUV scanner with a special emphasis on the added value of the new illuminator for increased pupil flexibility

Abstract

With the introduction of the NXE:3400B EUV scanner, ASML brings to the market the next generation NXE system. In this paper we present the results of a subset of a larger investigation that aimed at assessing the imaging performance of the NXE:3400B in various scenarios. The use cases we chose for the presentation here are contact holes, which are typical building blocks for logic and memory applications. In this paper we evaluate typical lithographic metrics. Starting from the exposure latitude, we show that contact holes of already 17nm half-pitch can be printed. Next, we show that the full wafer CD uniformity improvement is mainly driven by a high reticle CD uniformity. After that, we explore the capabilities of the new NXE:3400B illuminator and investigate an improved illumination setting for relaxed staggered contact holes of half pitch >21nm, and show a 20% local CD uniformity improvement (from 4.6 to 3.6nm) for regular contact holes of 18nm half-pitch, without throughput loss.