Defect transfer from immersion exposure process to etching process using novel immersion exposure and track system

For lithography technology to support the scaling down of semiconductor devices, 193-nm immersion exposure processing is being introduced to mass-production at a rapid pace. At the same time, there are still many unclear areas and many concerns to be addressed with regards to defects in 193-nm immersion lithography. To make 193-nm immersion lithography technology practical for mass production, it is essential that the defect problems be solved. Importance must be attached to understanding the conditions that give rise to defects and their transference in the steps between lithography and etching processes. It is apparent that double patterning (DP) will be the mainstream technology below 40nm node. It can be assumed that the risk of the defect generation will rise, because the number of the litho processing steps will be increased in DP. Especially, in the case of Litho-Etch-Litho-Etch (LELE) process, the concept of defect transfer becomes more important because etch processing is placed between each litho processing step. In this paper, we use 193-nm immersion lithography processing to examine the defect transference from lithography through the etching process for a representative 45nm metal layer substrate stack for device manufacturing. It will be shown which types of defects transfer from litho to etch and become killer defects.