Birgit Mecking

Optical lithography solutions for sub-65-nm semiconductor devices

In this paper we present a status update of the exposure tool developments for sub 65 nm CD’s. Main development path is 157-nm lithography. ASML follows a two step approach volume will be presented. Step 1 is based on the Micrascan step and scans platform and step 2 is based on the TWINSCAN platform. The progress of the development and first results on prototypes are discussed. This includes optics, purging, and pellicle status. The impact of CaF2 birefringence (intrinsic and stress induced) on lens performance is evaluated. Experimental data on optical path purging is presented. The pellicle status is reviewed, and results of hard pellicle testing in KrF scanners are presented. For the Micrascan system, first imaging and overlay results are presented.

157-nm technology: Where are we today?

In this paper we present a status overview of the development of 157-nm lithography. Solutions and challenges in the exposure system design are discussed. The solutions and challenges include optics, purging, and reticle handling issues. The impact of CaF2 birefringence (intrinsic and stress induced) on lens performance is evaluated. Experimental data on optical path purging and radiation cleaning is presented. The pellicle dilemma is reviewed, and feasibility of a thick glass plate pellicle is discussed. Additionally, a status summary on resist process development is given.

Optical lithography with 157-nm technology

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.