Immersion lithography exposure systems: today's capabilities and tomorrow’s expectations

Mulkens, Jan; Streefkerk, Bob; Hoogendorp, Martin; Moerman, R.; Leenders, Martijn; Jong, F. de; Stavenga, Marco; Boom, H.B.K.

doi:10.1117/12.606799

Cited by 7 publications

(4 citation statements)

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“…The Rayleigh equation applicable for immersion lithography, NA n k hp IF 1 (where hp is the 1:1 half pitch feature size, is the lithographic wavelength, n IF is the immersion fluid's index of refraction at the lithographic wavelength, NA is the numerical aperture of the stepper's lens, and k 1 is a measure of the lithographic process capability) allows one to see that the stepper NA is limited by the fluid's index. For example with water, the upper limit of the stepper's NA is 1.3 or 1.35.…”

Section: Roadmap For 193i Lithographic Opportunitymentioning

confidence: 99%

Second generation fluids for 193 nm immersion lithography

Peng

French

Qiu

et al. 2005

Optical Microlithography XVIII

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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.

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Section: Roadmap For 193i Lithographic Opportunitymentioning

confidence: 99%

Second generation fluids for 193 nm immersion lithography

Peng

French

Qiu

et al. 2005

Optical Microlithography XVIII

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“…Most of the issues related to ArF immersion lithography, especially for exposure tool, such as focusing, overlay and edge shot treatment have already been solved within a couple of years [1][2] . No fatal issue has been observed with 90nm node devices fabricated using full-field ArF immersion scanner [3][4] .…”

Section: Introductionmentioning

confidence: 99%

Studies on immersion defects using mimic immersion experiments

et al. 2006

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Top coat process is required for immersion lithography in order to prevent both the chemical contamination of scanner optics with eluted chemicals from resist material and the formation of residual droplet under the immersion exposure with high scanning speed. However, defect density of ArF immersion lithography with alkaline developer soluble type top coat material is much higher than that of ArF dry lithography. Mimic immersion experiments comprised of soaking of exposed conventional dry ArF resist with purified water followed by drying step were performed in order to study the immersion specific defects. It was suggested that the origin of immersion specific defects with alkaline developer soluble type top coat was the remaining water on and in the permeable top coat layer that might interfere the desired deprotection reaction of resist during post exposure bake (PEB). Therefore, application of post exposure rinse process that can eliminate the impact of the residual micro water droplets before PEB is indispensable for defect reduction. Post exposure rinse with optimized purified water dispense sequence was noticed to be valid for defect reduction in mimic immersion lithography, probably in actual immersion lithography.

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“…Thus, the immersion fluid enables light containing the higher spatial frequency information (which propagates at larger values of θ) to be coupled into the resist . However, building a lens system capable of hyper-NA imaging with a practical field and lens size has required shifting from all refractive dioptric lens designs to mirror-containing catadioptric designs. ,,− The numerical apertures of state-of-the-art 193 nm water immersion lithography scanners are 1.3−1.35 NA …”

Section: Introductionmentioning

confidence: 99%