Superior ArF PR etching selectivity and via CD control using fluorocarbon polymer deposition technique for 45nm-node

The fabrication process of semiconductor is more and more difficult as dimension scaling down. Especially, the via critical dimension (CD) and profile controls are the main challenges of ArF photo resist (PR) masking steps. This paper presents the unique technique using the masking protection step which is added at appropriate step in the via etch process to improve the via post etch profile. This technique has many merits such as using of single PR, easy control of CD, simple etching process and lower cost. The tri-layer process is currently is used in via process in device of 45nm-node. It is expected the much complicated photo layers are needed for device beyond 45nm-node. In this paper, a novel technique by controlling deposition of polymer from the protection layer is proposed. The results show superior PR etching selectivity to achieve good via CD and post etch profile and good clean efficiency of deposited polymer around via bottom and side wall.