Second generation fluids for 193 nm immersion lithography

S. Peng, R. H. French, Q W Y L CWRCM.  2004.  


Water is the first generation immersion fluid for 193 nm immersion lithography. With a fluid refractive index of 1.436 and an optical absorbance of 0.01/cm at 193 nm, water immersion technology can enable optical lithography for the {ITRS’} 65 nm half-pitch node. However, to achieve numerical apertures above 1.35 and to go beyond the 45 nm node, low absorbance fluids with indices higher than 1.6 are needed for the second generation of immersion lithography. We have developed a number of Gen. 2 high index fluids for immersion lithography at 193 nm. These highly transparent fluids have 193 nm indices up to 1.67. 32 nm 1:1 line space imaging has been demonstrated using two of our Gen 2 candidate fluids, representing major advance in optical lithography. To understand the behavior and performance of different fluid classes, we use spectral index measurements to characterize the index dispersion, coupled with Urbach absorption edge analysis, and Lorentz oscillator modeling.

Conference Name:

Proceedings of {SPIE}

Conference Location:

San Jose, {CA}, {USA}



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