Over the past years, ASML has taken the NXE pellicle concept (2015) from the concept level to pilot production (2016) and subsequently to a final product (2017 and onwards). In this paper we will show the progress in pellicle development that was made over the past year. After ASML started volume production of pellicles with the previous film generation, a new film generation was introduced end 2018. This new generation of pellicles shows considerable improvements in imaging performance, stability, EUV power capability and EUV reflectivity. The current generation of pellicle films show an EUV power capability of 250 Watts; improvements were also made in the imaging performance, where the EUV reflectivity of the pellicle reduced to below 0.04%. The EUV transmission of the latest pellicles increased to 83%.
A second phase in the immersion era is starting with the introduction of ultra high NA (NA >1) systems. These systems are targeting for 45 nm node device production and beyond. ASML TWINSCAN XT:1700i features a maximum NA of 1.2 and a 26x33 mm2 scanner field size. The projection lens is an in-line catadioptric lens design and the AERIAL XP illumination system enables conventional an off-axis illumination pupil shapes in either polarized or un-polarized modes at maximum light efficiency. In this paper a description and a performance overview of the TWINSCAN XT:1700i is given. We will present and discuss lithographic performance results, with special attention at low-k1 imaging using high NA and polarized illumination. Overlay, focus and productivity performance will also be presented.
This paper presents the progress of the 157 nm lithography program at ASML and Carl Zeiss SMT in 2003. The major technical problems are solved and the first full field 157 nm scanner was shipped to the industry for starting the process development. The progress in CaF2 material as well as production of CaF2 lens elements allow system to be produced for the 55 nm node. Contamination is shown to be at very low levels and a solution to reduce the influence of hard pellicles below 1 nm distortion is found. The first imaging results show a high depth of focus for 75 nm dense lines.
ASML's recently announced TWINSCAN$TM) lithography platform is specifically designed to meet the specific needs of handling and processing 300 mm substrates. This new platform, already supporting a family of Step & Scan lithography systems for I-line and 248 nm DUV, is designed to further support optical lithography at its limits with systems for 193 nm and 157 nm. The conflicting requirements associated with higher productivity on one side, and more extensive metrology on the other, have led to the development of a platform with two independent wafer stages operating in parallel. The hardware associated with exposure, and the hardware and sub-systems required for metrology, are located in two separate positions. While a wafer is exposed on one stage, wafer unload/load and measurements of the horizontal and vertical wafer maps are done in parallel on the second stage. After the two processes are completed, where the exposure sequence typically is the longest, the two stages are swapped. The process is continued on the second stage, while the first stage unloads the exposed wafer and starts the process again.