High Refractive Index Fluid for Next Generation ArF Immersion Lithography

ArF immersion lithography using a high-refractive-index fluid (HIF) is considered to be one of the most promising candidates for hp38nm or below. We have developed JSR HIL-001 and HIL-002 as new immersion fluids, the refractive index and transmittance of which are 1.64, >98%/mm and 1.65, >99%/mm (193.4nm, 23&deg:C), respectively. Using HIL-001 immersion and a two-beam interferometric exposure tool, hp30nm imaging has been demonstrated. However, despite the remarkable advances of recent HIF research, there is still a lot of issue about whether an organic fluid can be used in immersion lithography, since optical and photochemical behaviors of organic fluids at ArF wavelength have not been well understood so far. Besides, cost and disposal issues will be encountered when the organic immersion fluid is substituted for water. In this paper, we will address such problems by reporting our updated results on research of JSR HILs.