The demand for even denser semiconductor devices is driving efforts to reduce pattern dimensions in semiconductor lithography. It has been found that 193-nm immersion lithography technology can achieve smaller patterns without having to modify the infrastructure technology of existing state-of-the-art 193-nm dry lithography. This has made 193-nm immersion lithography a promising technology for next-generation mass production processes. It is now under full-scale development and is about to enter a commercial stage applicable to mass production. In 193-nm immersion lithography, the space between the optical projection system and silicon wafer is filled with liquid thereby immersing the resist film in de-ionized water during exposure. This generates a number of concerns, such as the penetration of moisture into the resist, the leaching of resist components into deionized water, and the presence of residual moisture, all of which can lead to defects that can affect post-processing. It has been reported; however, that rinse processing before and after exposure can be effective in reducing such defects [1]. Also, the trend toward finer patterns has resulted in large aspect ratios that can lead to pattern collapse, but the application of a surfactant has been found to ease this problem. Controlling the drying process after rinsing has also been found to reduce residue adhering to the resist. The stability of process data is considered to be a crucial factor in the adapting of 193-nm immersion lithography to mass production. In this report, we obtain long-term data on defects and critical dimension (CD), examine this data for process stability, and discuss the applicability of 193-nm immersion lithography to mass production.

Date Published: 2 April 2007
PDF: 10 pages
Proc. SPIE 6519, Advances in Resist Materials and Processing Technology XXIV, 65190C (2 April 2007);

Published in SPIE Proceedings Vol. 6519:
Advances in Resist Materials and Processing Technology XXIV
Qinghuang Lin, Editor(s)