Multi-layer BARCs for Hyper-NA immersion lithography process

摘要

Organic Bottom Anti-Reflective Coatings (BARCs) has been used in the lithography process. BARCs may play an important role to control reflections and improve swing ratios, CD variations, reflective notching, and standing waves. In 32-45nm node, application of the immersion lithography technique is not avoided to obtain the high resolution. To obtain the high resolution, numerical aperture (NA) of the optical system needs the Hyper-NA lens of 1.0 or more but come up to the problem of affections the polarized light in the Hyper-NA lens. The substrate of reflection control also will become more difficult by using single BARCs system and the thin film resist becomes the necessity and indispensable at Hyper-NA lithography. To achieve an appropriate reflection control, to suppress the CD difference to the minimum, and to prevent the pattern collapse, hard mask with the spin coating film and antireflection characteristic is needed. In order to solve these issues, we designed and developed new materials with the suitable optical parameter, square resist shape and large dry etching selectivity. These Multi-layer materials of each process are spin-coated by using the current system and conventional ArF photo resist or immersion resist is available in this process. This paper presents the detail of our newest materials for Hyper NA lithography.